Exfoliation syndrome

Minimal phenotypes in transgenic mice with the human LOXL1/LOXL1-AS1 locus associated with exfoliation glaucoma

Exfoliation syndrome is a leading cause of secondary glaucoma worldwide. Among the risk-factors for exfoliation syndrome and exfoliation glaucoma that have been investigated, a genetic association with 15q24.1 is among the most striking. The leading candidates for the causal gene at this locus are LOXL1 and/or LOXL1-AS1, but studies have not yet coalesced in establishing, or ruling out, either candidate. Here, we contribute to studies of the 15q24.1 locus by making a partially humanized mouse model in which 166 kb of human genomic DNA from the 15q24.1 locus was introduced into the mouse genome via BAC transgenesis (B6-Tg(RP11-71M11)Andm). Transgenic expression of human genes in the BAC was only detectable for LOXL1-AS1. One cohort of 34 mice (21 experimental hemizygotes and 13 non-carrier control littermates) was assessed by slit-lamp exams and SD-OCT imaging at early (1-2 months) and mid (4-5 months) time points; fundus exams were performed at 5 months of age. A second smaller cohort (3 hemizygotes) were aged extensively (>12 months) to screen for overt abnormalities. Across all genotypes and ages, 136 slit-lamp exams, 128 SD-OCT exams, and 42 fundus exams detected no overt indices of exfoliation syndrome. Quantitatively, small, but statistically significant, age-related declines in ganglion cell complex thickness and total retinal thickness were detected in the hemizygotes at 4 months of age. Overall, this study demonstrates complexity in gene regulation from the 15q24.1 locus and suggests that LOXL1-AS1 is unlikely to be a monogenic cause of exfoliation syndrome but may contribute to glaucomatous retinal damage.

Former smoking as a risk factor for visual field progression in exfoliation glaucoma patients in Sweden

PURPOSE

The present study aimed to identify whether former smoking was a risk factor for visual field progression in exfoliation glaucoma patients.

METHODS

Prospective nonrandomised cohort study. The study included patients diagnosed with exfoliation glaucoma. All included patients were followed for three years (± three months) with reliable visual fields. At least five reliable visual fields needed to be included in the study. Exfoliation glaucoma was defined using the European Glaucoma Society Guidelines. The visual fields were tested using the 24-2 test strategy of the Humphrey Field Analyzer. Smoking was assessed through questionnaires. Outcomes: Visual field progression. Three different approaches were used: difference in mean deviation (MD), rate of progression (ROP), and guided progression analysis (GPA).

RESULTS

In total, n = 113 patients were included; among them, n = 57 were smokers. Smoking was a significant predictor for visual field progression in the three models (MD/ROP/GPA) studied (p = 0.01/p = 0.001/p ≤ 0.001), even adjusting for intraocular pressure (IOP). Other predictors were included in the MD model: IOP at diagnosis (p = 0.04) and selective laser trabeculoplasty (SLT) treatment (p = 0.01). Other predictors were in the ROP model: Visual field index (p = 0.005), number of medications (p = 0.001) and SLT treatment (p = 0.001). The number of medications was another predictor in the GPA model (p = 0.002).

CONCLUSIONS

Former smoking induced visual field deterioration in all models studied. Smoking status should be considered when establishing the glaucoma diagnosis. Increased glaucoma care should be provided to former smokers to slow the progression of the disease.

High-risk factors for zonular complications during cataract surgery in eyes with pseudoexfoliation syndrome

AIMS

To predict high-risk factors for zonular complications during cataract surgery due to pre-existing severe zonular dehiscence in eyes with pseudoexfoliation (PXF) syndrome.

METHODS

315 eyes of 315 consecutive patients with PXF scheduled for phacoemulsification surgery underwent preoperative examination of various ocular parameters using an anterior segment-optical coherence tomography and other devices. When zonular complications occurred during surgery due to zonular dehiscence, scleral fixation of the intraocular lens (IOL) or implantation of a capsular tension ring (CTR) was performed. High-risk factors for these intraoperative zonular complications were examined using classification-tree and logistic regression analyses.

RESULTS

Of the 315 eyes, 31 (9.84%) underwent scleral IOL fixation or CTR implantation. High-risk factors identified by classification-tree analysis were a small pupillary diameter after mydriasis <6.30 mm, a shallow anterior chamber depth <2.074 mm and lens decentration >0.260 mm. Based on exact logistic regression analysis, the OR was 4.81-fold higher for eyes with poor mydriasis than for eyes without poor mydriasis (p=0.006, 95% CI 1.49 to 18.23), 23.99-fold higher for eyes with poor mydriasis and a shallow anterior chamber (p<0.001, 5.92 to 109.02) and 287.39-fold higher for eyes with poor mydriasis, a shallow chamber and great lens decentration (p<0.001, 50.46 to infinity).

CONCLUSION

In eyes with PXF, high-risk factors for zonular complications during cataract surgery due to pre-existing severe zonular dehiscence were poor mydriasis, shallow anterior chamber and large lens decentration, suggesting the importance of evaluating these conditions preoperatively.

Prevalence and prediction of intraoperative floppy iris syndrome in patients with pseudoexfoliation syndrome

OBJECTIVE

To investigate the incidence of intraoperative floppy iris syndrome (IFIS) in patients with pseudoexfoliation syndrome (PXF) and analyze preoperative ocular predicting factors.

DESIGN

A retrospective case-control study METHODS: The study included 224 eyes with PXF and 287 control eyes without PXF. One eye per patient, who underwent cataract surgery at the Wolfson Medical Center between January 2020 to December 2021, was included. Medical records of the patients were reviewed. Data collected included demographic characteristics, medical history, preoperative comprehensive ophthalmic examination, biometry, surgical procedure details, and IFIS occurrence. The association of IFIS with preoperative ocular parameters was analyzed through both univariant and multivariant analyses.

RESULTS

Patients with PXF were older and had a higher prevalence of glaucoma (77.6 ± 6.4 years vs 74.2±7.6 years; p < 0.001, and 20.1 % vs 9.8 %, p < 0.001, respectively). Prevalence of α-blockers treatment was similar in both groups. IFIS rate among the PXF group was 12.5% (n = 28) compared to 7.3% (n = 21) in the control group (p < 0.05). When omitting patients exposed to α-blockers, the PXF group exhibited a significantly higher IFIS rate (9.9% vs 4.8%; p < 0.05). Pupil dilation diameter was significantly lower among PXF patients (5.8 ± 1.1 mm vs 6.9 ± 0.99 mm; p < 0.001). Biometric evaluation revealed significant differences in anterior segment depth (ACD) and lens thickness (LT). Multivariate analysis indicated that PXF and decreased mydriatic pupil size remained significant predictors of IFIS.

CONCLUSION

This study establishes an association between PXF and an increased risk of IFIS during cataract surgery, independent of α-blockers treatment.

A Prospective Comparison of 180 Versus 360-Degree Gonioscopy-Assisted Transluminal Trabeculotomy Outcomes in Pseudoexfoliation Glaucoma

PRCIS

Analysis of surgical success and intraocular pressure (IOP), best-corrected visual acuity (BCVA), and antiglaucomatous medication (AGM) changes between segmental 180-degree and 360-degree gonioscopy-assisted transluminal trabeculectomy (GATT) in patients with pseudoexfoliation glaucoma (PEXG) showed no significant difference.

OBJECTIVE

To compare surgical outcomes of segmental 180-degree and 360-degree GATT in patients with PEXG.

MATERIALS AND METHODS

Prospective, comparative study of 65 PEXG eyes, who underwent segmental 180-degree GATT (GATT 180-degree group, 31 eyes) and 360-degree GATT (GATT 360-degree group, 34 eyes) in a tertiary academic center over a 12-month of follow-up. Primary outcome was qualified and complete surgical success rates for criterion A (IOP <18 mm Hg and >30% reduction) and criterion B (IOP <15 mm Hg and >30% reduction). Secondary outcome measures included IOP reduction, BCVA change, AGM use, and postoperative complications.

RESULTS

The probabilities of qualified and complete success rates both for criteria A and B did not significantly differ between the groups ( P > 0.05). IOP and BCVA levels were similar at each time point ( P > 0.05). IOP reduction was 59.3 ± 9.5% in the GATT 180-degree group and 55.8 ± 18.1% in the GATT 360-degree group ( P = 0.33). No significant difference in the mean number of AGM was present at the 12-month visit (1.2 ± 1.1 in GATT 180-degree group vs 1.5 ± 1.2 in GATT 360-degree group, P = 0.25). Significantly higher incidences of postoperative hyphema and IOP spikes were observed in the GATT 360-degree group ( P = 0.01 and P = 0.008, respectively).

CONCLUSION

Both segmental 180-degree and 360-degree GATT similarly reduced IOP and AGM with comparable surgical success rates in patients with PEXG at the end of 12 months. Postoperative hyphema and IOP spike rates were significantly higher after 360-degree GATT. Segmental 180-degree GATT may be sufficient to adequately modulate IOP with a lower incidence of postoperative complications in PEXG.

Enhanced Optic Nerve Expansion and Altered Ultrastructure of Elastic Fibers Induced by Lysyl Oxidase Inhibition in a Mouse Model of Marfan Syndrome

Two major constituents of exfoliation material, fibrillin-1 and lysyl oxidase-like 1 (encoded by FBN1 and LOXL1), are implicated in exfoliation glaucoma, yet their individual contributions to ocular phenotype are minor. To test the hypothesis that a combination of FBN1 mutation and LOXL1 deficiency exacerbates ocular phenotypes, the pan-lysyl oxidase inhibitor β-aminopropionitrile (BAPN) was used to treat adult wild-type (WT) mice and mice heterozygous for a missense mutation in Fbn1 (Fbn1C1041G/+) for 8 weeks and their eyes were examined. Although intraocular pressure did not change and exfoliation material was not detected in the eyes, BAPN treatment worsened optic nerve and axon expansion in Fbn1C1041G/+ mice, an early sign of axonal damage in rodent models of glaucoma. Disruption of elastic fibers was detected only in Fbn1C1041G/+ mice, which increased with BAPN treatment, as shown by histologic and immunohistochemical staining of the optic nerve pia mater. Transmission electron microscopy showed that Fbn1C1041G/+ mice had fewer microfibrils, smaller elastin cores, and a lower density of elastic fibers compared with WT mice in control groups. BAPN treatment led to elastin core expansion in both WT and Fbn1C1041G/+ mice, but an increase in the density of elastic fiber was confined to Fbn1C1041G/+ mice. LOX inhibition had a stronger effect on optic nerve and elastic fiber parameters in the context of Fbn1 mutation, indicating the Marfan mouse model with LOX inhibition warrants further investigation for exfoliation glaucoma pathogenesis.

In Search of Mouse Models for Exfoliation Syndrome

PURPOSE

Exfoliation syndrome (XFS) is a systemic connective tissue disorder with elusive pathophysiology. We hypothesize that a mouse model with elastic fiber defects caused by lack of lysyl oxidase like 1 (LOXL1 encoded by Loxl1), combined with microfibril deficiency due to Fbn1 mutation (encoding fibrillin-1, Fbn1C1041G/+) will display ocular and systemic phenotypes of XFS.

METHODS

Loxl1-/- was crossed with Fbn1C1041G/+ to create double mutant (dbm) mice. Intraocular pressure (IOP), visual acuity (VA), electroretinogram (ERG), and biometry were characterized in 4 genotypes (wt, Fbn1C1041G/+, Loxl1-/-, dbm) at 16 weeks of age. Optic nerve (ON) area was measured by ImageJ, and axon counting was achieved by AxonJ. Deep whole-body phenotyping was performed in wt and dbm mice. Two-tailed Student t test was used for statistical analysis.

RESULTS

There was no difference in IOP between the 4 genotypes. VA was significantly reduced only in dbm mice. The majority of biometric parameters showed significant differences in all 3 mutant genotypes compared with wt, and dbm had exacerbated anomalies compared with single mutants. Dbm mice showed reduced retinal function and significantly enlarged ON area compared with wt. Dbm mice exhibited severe systemic phenotypes related to abnormal elastic fibers, such as pelvic organ prolapse and cardiovascular and pulmonary abnormalities.

CONCLUSIONS

Ocular and systemic findings in dbm mice support functional overlap between fibrillin-1 and LOXL1, 2 prominent components of exfoliation material. Although no elevated IOP or reduction of axon numbers was detected in dbm mice at 16 weeks of age, their reduced retinal function and enlarged ON area indicate early retinal ganglion cell dysfunction. Dbm mice also provide insight on the link between XFS and systemic diseases in humans.

Harnessing Standing Sound Waves to Treat Intraocular Blood Cell Accumulation

Certain ocular conditions result from the non-physiological presence of intraocular particles, leading to visual impairment and potential long-term damage. This happens when the normally clear aqueous humor becomes less transparent, thus blocking the visual axis and by intraocular pressure elevation due to blockage of the trabecular meshwork, as seen in secondary open-angle glaucoma (SOAG). Some of these "particle-related pathologies" acquire ocular conditions like pigment dispersion syndrome, pseodoexfoliation and uveitis. Others are trauma-related, such as blood cell accumulation in hyphema. While medical and surgical treatments exist for SOAG, there is a notable absence of effective preventive measures. Consequently, the prevailing clinical approach predominantly adopts a "wait and see" strategy, wherein the focus lies on managing secondary complications and offers no treatment options for particulate matter disposal. We developed a new technique utilizing standing acoustic waves to trap and direct intraocular particles. By employing acoustic trapping at nodal regions and controlled movement of the acoustic transducer, we successfully directed these particles to specific locations within the angle. Here, we demonstrate control and movement of polystyrene (PS) particles to specific locations within an in vitro eye model, as well as blood cells in porcine eyes (ex vivo). The removal of particles from certain areas can facilitate the outflow of aqueous humor (AH) and help maintain optimal intraocular pressure (IOP) levels, resulting in a non-invasive tool for preventing secondary glaucoma. Furthermore, by controlling the location of trapped particles we can hasten the clearance of the AH and improve visual acuity and quality more effectively. This study represents a significant step towards the practical application of our technique in clinical use.

Lack of evidence for GWAS signals of exfoliation glaucoma working via monogenic loss-of-function mutation in the nearest gene

PURPOSE

Exfoliation syndrome (XFS) is a systemic disease of elastin-rich tissues involving a deposition of fibrillar exfoliative material (XFM) in the anterior chamber of the eye, which can promote glaucoma. The purpose of this study was to create mice with CRISPR/Cas9-induced variations in candidate genes identified from human genome-wide association studies (GWAS) and screen them for indices of XFS.

METHODS

Variants predicted to be deleterious were sought in the Agpat1, Cacna1a, Loxl1, Pomp, Rbms3, Sema6a, and Tlcd5 genes of C57BL/6J mice using CRISPR/Cas9-based gene editing. Strains were phenotyped by slit-lamp, SD-OCT imaging, and fundus exams at 1-5 mos of age. Smaller cohorts of 12-mos-old mice were also studied.

RESULTS

Deleterious variants were identified in six targets; Pomp was recalcitrant to targeting. Multiple alleles of some targets were isolated, yielding 12 strains. Across all genotypes and ages, 277 mice were assessed by 902 slit-lamp exams, 928 SD-OCT exams, and 358 fundus exams. Homozygosity for Agpat1 or Cacna1a mutations led to early lethality; homozygosity for Loxl1 mutations led to pelvic organ prolapse, preventing aging. Loxl1 homozygotes exhibited a conjunctival phenotype of potential relevance to XFS. Multiple other genotype-specific phenotypes were variously identified. XFM was not observed in any mice.

CONCLUSIONS

This study did not detect XFM in any of the strains. This may have been due to species-specific differences, background dependence, or insufficient aging. Alternatively, it is possible that the current candidates, selected based on proximity to GWAS signals, are not effectors acting via monogenic loss-of-function mechanisms.

Macula vessel density and its relationship with the central visual field mean sensitivity across different stages of exfoliation glaucoma

CLINICAL RELEVANCE

Alterations in ocular microvasculature may contribute to pathogenesis of exfoliation glaucoma (XFG) and may improve monitoring this aggressive type of open angle glaucoma.

BACKGROUND

This work aims to compare the macula vessel density and the relationship between macula vessel density and central visual field mean sensitivity between eyes with XFG and eyes with primary open-angle glaucoma (POAG) of different stages.

METHODS

In this cross-sectional observational study, the macula vessel density values were compared among 52 POAG cases (26 early stage, 26 moderate to advanced stage) and 53 XFG cases (27 early stage, 26 moderate to advanced stage). The vessel density values were evaluated with optical coherence tomography angiography. Vasculature-function and structure-function relationships were analysed by comparing macula vessel density, inner macula thickness and visual field mean sensitivity in early and moderate to advanced stages of XFG and POAG eyes separately.

RESULTS

The early stage XFG eyes had a significantly lower global macula vessel density compared with early stage POAG eyes (42.81 ± 3.85% and 46.56 ± 3.90%, respectively; p = 0.02). However, the tendency of XFG eyes for a lower vessel density compared with the POAG eyes did not exhibit any significance in moderate to advanced stages of glaucoma (37.39 ± 5.65% and 38.35 ± 4.67%, respectively; p = 0.9). The macula vessel density (%)-visual field mean sensitivity (1/Lambert) correlation was statistically significant in early stage XFG eyes (r = 0.464 p = 0.01), while no such correlation was notable for the early stage POAG eyes (r = -0.029 p = 0.89).

CONCLUSION

The macula vessel density appears to be more severely affected in early stage XFG than POAG of similar severity, suggesting a relatively greater value of vascular insufficiency in XFG. The significant vasculature-function association in early stage XFG, which was absent in early stage POAG, may infer the importance of macula vessel density in monitoring functional loss in early stages of XFG.

[Intraoperative Complications in Cataract Surgery]

Cataract surgery is frequently and successfully performed in the developed world. The indications for the operation have shifted on one hand towards healthier patients seeking freedom from glasses and on the other hand towards more complex cases. How should the patient be informed? What complications can occur intraoperatively, and what treatment options are available for these complications?This article offers a focus on conditions such as zonulopathy and pseudoexfoliation that can pose challenges to cataract surgery. It discusses the use of specialized tools such as capsular tension rings and capsular hooks and precise maneuvers to minimize stress on weakened zonules in order to ensure in-the-bag fixation of the IOL.Furthermore, the article addresses appropriate actions towards intraoperative complications such as anterior or posterior capsule ruptures and loss of nuclear fragments into the vitreous cavity.Exploring innovative advancements, this article presents the latest alternatives for intracapsular lens fixation, such as sutureless scleral fixation and emerging lens designs in cases where there is insufficient capsular support.Ultimately, the primary objective remains delivering optimal outcomes even for complex cases, and minimizing post-surgical issues. Numerous tools and techniques are available.

Pseudoexfoliation Syndrome Presenting With Bilateral Visual Impairment and Intraocular Pressure Discrepancy: A Case Report

Pseudoexfoliation syndrome (PEX) presents a significant clinical challenge due to its diverse ocular manifestations, including glaucoma and zonular weakness of the lens, which can lead to irreversible visual impairment if left untreated. We report a case of a 78-year-old male presenting with bilateral visual impairment persisting for four years, with a more pronounced decline in the right eye over the past six months. Examination revealed aphakia with pseudoexfoliative material in the right eye, a cataract with pseudoexfoliative material in the left eye, and a notable intraocular pressure (IOP) discrepancy. Surgical intervention was required for both eyes, with cataract extraction and IOP-lowering procedures performed to preserve vision and prevent further deterioration. This case underscores the importance of timely recognition and comprehensive management of PEX-related ocular complications to optimize visual outcomes and quality of life for affected individuals. Close collaboration between ophthalmologists and other healthcare professionals is essential to address the multifaceted nature of PEX and tailoring treatment strategies to individual patient needs. Further research is needed to elucidate the underlying pathophysiology of PEX and refine therapeutic approaches to mitigate its detrimental effects on vision.

Outcome of manual small incision cataract surgery in patients with pseudoexfoliation syndrome and pseudoexfoliation glaucoma

PURPOSE

The study aimed to analyze the surgical outcome of manual small incision cataract surgery (MSICS) in patients with pseudoexfoliation syndrome (PXF) and pseudoexfoliation glaucoma (PXG) and compare them with those of controls.

SETTINGS AND DESIGN

This prospective, observational, and comparative study included 150 cases of PXF with cataracts, 150 cases of PXG with cataracts, and 200 cases of cataracts without PXF as controls.

METHODS

MSICS was performed in all cases under peribulbar anesthesia. Intraoperative complications, if any, were noted. Best-corrected visual acuity (BCVA), intraocular pressure (IOP), and postoperative complications were recorded at follow-up on day 1, day 7, and after 1 month.

STATISTICAL ANALYSIS USED

IBM SPSS 24.0 statistics, SPSS South Asia Pvt Ltd.

RESULTS

Lines of improvement in BCVA were significantly better in the control group (8.7 ± 1.7) than that in the PXF (7.5 ± 2.1) and PXG groups (6.4 ± 2.7). IOP significantly decreased from baseline to 1 month postoperatively in the PXG group than in the PXF and control groups (mean difference: 3.8 ± 7.5 mm Hg). Intraoperative iridodialysis and zonular dialysis were significantly high in the PXG group with a proportion of 4 and 20%, respectively. Postoperative choroidal detachment and hyphema, six cases each, were found significantly high in the PXG group.

CONCLUSION

Although the BCVA improvement was less and the complications were high in patients with pseudoexfoliation, especially those with PXG, the reduction in IOP was significant. MSICS can be considered favorably in patients with PXF and PXG, with adequate precautions to manage anticipated complications.

Glaucoma, Pseudoexfoliation and Hearing Loss: A Systematic Literature Review

Purpose: To investigate the relationship between glaucoma, pseudoexfoliation and hearing loss (HL). Methods: A systematic literature search following PRISMA guidelines was conducted using the PubMed, Embase, Scopus and Cochrane databases from 1995 up to 28 August 2023. Results: Thirty studies out of the 520 records screened met the inclusion criteria and were included. Most articles (n = 20) analysed the association between pseudoexfoliation syndrome (XFS) and HL, showing XFS patients to have higher prevalence of sensorineural hearing loss (SNHL) at both speech frequencies (0.25, 0.5, 1 and 2 kHz), and higher frequencies (4 and 8 kHz) compared to controls in most cases. No significant differences in prevalence or level of HL between XFS and pseudoexfoliative glaucoma (XFG) were detected in most studies. Eight articles analysed the relationship between primary open-angle glaucoma (POAG) and HL. Overall, a positive association between the two conditions was highlighted across all studies except for two cases. Similarly, articles focusing on NTG and HL (n = 4) showed a positive association in most cases. The role of autoimmunity and, in particular, the presence of antiphosphatidylserine antibodies (APSA) in patients with NTG and HL suggested an underlying autoimmune or vascular mechanism contributing to their pathogenesis. Only one study analysed the relationship between angle-closure glaucoma (ACG) and HL, showing higher incidence of ACG in patients with SNHL compared to normal hearing controls. Conclusions: Most studies detected an association between XFS and HL as well as POAG/NTG/ACG and HL, suggesting the presence of a similar pathophysiology of neurodegeneration. However, given the strength of the association of XFS with HL, it remains unclear whether the presence of XFG is further associated with SNHL. Further research specifically targeted to assess the correlation between glaucoma, XFS and HL is warranted to provide a more comprehensive understanding of this association.

Characteristic Differences between Normotensive and Hypertensive Pseudoexfoliative Glaucoma

PURPOSE

To compare the differences between eyes with pseudoexfoliative glaucoma (PXG) when they are divided into two groups (hypertensive PXG and normotensive PXG) according to the intraocular pressure (IOP).

METHODS

This is a retrospective study. Data from 86 hypertensive PXG eyes and 80 normotensive PXG eyes were included. Hypertensive PXG was defined as PXG with IOP ≥ 22 mmHg, and normotensive PXG was defined as with IOP ≤ 21 mmHg). Central corneal thickness (CCT) was measured by ultrasound pachymetry. Lamina cribrosa thickness (LT) was evaluated using swept-source optical coherence tomography.

RESULTS

No significant differences were observed between hypertensive and normotensive PXG in terms of age, gender, axial length, hypertension, or diabetes. Normotensive PXG eyes had thinner CCT than hypertensive PXG eyes (p = 0.02). To compare LT, a sub-analysis was performed after matching age, VF MD and retinal nerve fiber layer thickness. The normotensive PXG group (n = 32) demonstrated significantly thinner LT compared with the hypertensive PXG group (n = 32) at similar ages and levels of glaucoma severity (p < 0.001).

CONCLUSIONS

Eyes with normotensive PXG demonstrated thinner CCT and LT compared with those with hypertensive PXG, suggesting structural vulnerability to glaucoma.

Clinical outcomes of Ahmed glaucoma valve implantation in primary open-angle glaucoma and pseudoexfoliative glaucoma

PURPOSE

To investigate the clinical outcomes of Ahmed glaucoma valve (AGV) implantation in primary open-angle glaucoma (POAG) and pseudoexfoliative glaucoma (PEXG).

METHODS

The patients who underwent AGV implantation for POAG and PEXG between January 2015 and December 2021 in a single tertiary center eye clinic were reviewed retrospectively. Thirty-one eyes with the diagnosis of POAG constituted Group 1 and 40 eyes with the diagnosis of PEXG constituted Group 2. The primary outcome measures were intraocular pressure (IOP) changes after AGV implantation and surgical success at the last visit. We evaluated complete and qualified surgical success using the following three criteria: (1) IOP ≤ 21mmH g, (2) IOP ≤ 18 mmHg, and (3) IOP ≤ 15 mmHg, as well as the absence of any serious complications, such as light perception loss and phthisis bulbi, and additional de novo glaucoma surgery.

RESULTS

The mean follow-up times were 25.2 (± 21.4) months and 27.6 (± 19.8) months for Groups 1 and 2, respectively (p > 0.05). In Groups 1 and 2, the mean preoperative IOPs were 31.9 ± 9.4 mmHg and 32.3 ± 8.4 mmHg, respectively, which significantly reduced to 14.5 ± 0.7 mmHg and 11.6 ± 0.6 mmHg, respectively at the last postoperative visit (p < 0.001 for both). The mean IOP value at the last visit was statistically significantly lower in Group 2 (p = 0.006). At the last visit, the number of eyes with qualified success according to criteria 1, 2, and 3 was 26 (83.9%), 25 (80.6%), and 18 (58.1%), respectively, in Group 1 and 39 (97.5%), 39 (97.5%), and 32 (80%), respectively, in Group 2. The comparison of the qualified success rates showed statistically significantly higher rates in Group 2 for criterion 2 (p = 0.038).

CONCLUSION

AGV implantation had high success rates in both POAG and PEXG, but at the final visit, lower IOP levels were reached in the latter.

Comparison of Schlemm's Canal Morphology Parameters Between Propensity Score-Matched Primary Open-Angle Glaucoma and Exfoliation Glaucoma

Purpose

This study aimed to histologically compare the status of Schlemm's canal (SC) and Schlemm's canal endothelial (SCE) cells between trabeculectomy specimens from patients with primary open-angle glaucoma (POAG) and exfoliation glaucoma (EXG).

Methods

A total of 182 eyes from 152 patients with POAG and 138 eyes from 116 patients with EXG underwent immunohistochemical staining for thrombomodulin. Equal numbers of cases were selected from both groups using propensity score matching. The following parameters were evaluated: total SC length, staining positive and negative SC length (PSC and NSC, respectively), opened and closed SC length, staining positive and opened SC length, staining positive and closed SC length, staining negative and opened SC length (NOSC), and staining negative and closed SC length.

Results

After matching for age and gender, 87 cases were selected in each group. The EXG group had significantly higher preoperative IOP and medication scores. PSC was significantly longer in the POAG group, while NSC and NOSC were longer in the EXG group. Multiple regression analysis of these 174 cases revealed that PSC was significantly shorter in the EXG group. After matching for age, gender, preoperative IOP, and medication score, 64 cases were selected in each group, and NOSC was significantly longer in the EXG group.

Conclusions

These findings suggest that in EXG, SCE loss occurs independently of background factors such as aging and medication use. The loss of SCE may have a more critical impact on IOP elevation in EXG compared to POAG.

Identification of biomarker candidates for exfoliative glaucoma from autoimmunity profiling

BACKGROUND

Exfoliative glaucoma (XFG) is a subtype of open-angle glaucoma characterized by distinctive extracellular fibrils and a yet unknown pathogenesis potentially involving immune-related factors. The aim of this exploratory study was to identify biomarkers for XFG using data from autoimmunity profiling performed on blood samples from a Scandinavian cohort of patients.

METHODS

Autoantibody screening was analyzed against 258 different protein fragments in blood samples taken from 30 patients diagnosed with XFG and 30 healthy donors. The 258 protein fragments were selected based on a preliminary study performed on 3072 randomly selected antigens and antigens associated with the eye. The "limma" package was used to perform moderated t-tests on the proteomic data to identify differentially expressed reactivity between the groups.

RESULTS

Multiple associated genes were highlighted as possible biomarker candidates including FUT2, CDH5, and the LOX family genes. Using seven variables, our binary logistic regression model was able to classify the cases from the controls with an AUC of 0.85, and our reduced model using only one variable corresponding to the FUT2 gene provided an AUC of 0.75, based on LOOCV. Furthermore, over-representation gene analysis was performed to identify pathways that were associated with antigens differentially bound to self-antibodies. This highlighted the enrichment of pathways related to collagen fibril formation and the regulatory molecules mir-3176 and mir-876-5p.

CONCLUSIONS

This study suggests several potential biomarkers that may be useful in developing further models of the pathology of XFG. In particular, CDH5, FUT2, and the LOX family seem to have a relationship which merits additional exploration.

Secondary glaucoma: Toward interventions based on molecular underpinnings

Glaucoma is a heterogeneous group of progressive diseases that leads to irreversible blindness. Secondary glaucoma refers to glaucoma caused by a known underlying condition. Pseudoexfoliation and pigment dispersion syndromes are common causes of secondary glaucoma. Their respective deposits may obstruct the trabecular meshwork, leading to aqueous humor outflow resistance, ocular hypertension, and optic neuropathy. There are no disease-specific interventions available for either. Pseudoexfoliation syndrome is characterized by fibrillar deposits (pseudoexfoliative material) on anterior segment structures. Over a decade of multiomics analyses taken together with the current knowledge on pseudoexfoliative glaucoma warrant a re-think of mechanistic possibilities. We propose that the presence of nucleation centers (e.g., vitamin D binding protein), crosslinking enzymes (e.g., transglutaminase 2), aberrant extracellular matrix, flawed endocytosis, and abnormal aqueous-blood barrier contribute to the formation of proteolytically resistant pseudoexfoliative material. Pigment dispersion syndrome is characterized by abnormal iridolenticular contact that disrupts iris pigment epithelium and liberates melanin granules. Iris melanogenesis is aberrant in this condition. Cytotoxic melanogenesis intermediates leak out of melanosomes and cause iris melanocyte and pigment epithelium cell death. Targeting melanogenesis can likely decrease the risk of pigmentary glaucoma. Skin and melanoma research provides insights into potential therapeutics. We propose that specific prostanoid agonists and fenofibrates may reduce melanogenesis by inhibiting cholesterol internalization and de novo synthesis. Additionally, melatonin is a potent melanogenesis suppressor, antioxidant, and hypotensive agent, rendering it a valuable agent for pigmentary glaucoma. In pseudoexfoliative glaucoma, where environmental insults drive pseudoexfoliative material formation, melatonin's antioxidant and hypotensive properties may offer adjunct therapeutic benefits. This article is categorized under: Neurological Diseases > Molecular and Cellular Physiology.

Genetic Aspects of Glaucoma: An Updated Review

Glaucoma is a group of diverse diseases characterized by cupping of the optic nerve head due to the loss of retinal ganglion cells. It is the most common cause of irreversible blindness throughout the world; therefore, its timely diagnosis and early detection through an ophthalmological examination are very important. We, herein, present the information on the epidemiology, pathophysiology, clinical diagnosis, and treatment of glaucoma. We also emphasize the investigations of the last decades that have allowed identifying numerous genes and susceptibility genetic factors. We have also described in detail the genes whose mutations cause or contribute to the development of the disease.

Diagnostic ability of vessel density of the optic nerve head and macula versus structural parameters with optical coherence tomography in pseudoexfoliative glaucoma

PURPOSE

To evaluate the diagnostic ability of the vessel density (VD) of the optic nerve head (ONH) and the macula on optical coherence tomography (OCT) angiography and the retinal nerve layer thickness (RNFL) thickness and the macular ganglion cell complex (GCC) thickness on OCT in patients with pseudoexfoliative glaucoma (PXG).

METHODS

Cross-sectional study including PXG patients and healthy controls. Demographic and clinical data were noted for all participants. Optical coherence tomography (OCT) and OCT angiography (OCTA) images of the ONH and macular area were obtained with the RS-3000 Advance OCT (Nidek Co., Gamagori, Japan). The RNFL and GCC thickness of different sectors was provided by the software. Macular VD of the superficial capillary plexus (SCP) and ONH VD of the radial peripapillary capillary plexus (RPCP) were registered. Groups were compared and area under the receiver operating characteristic (AUROC) curves were used to determine the power of discrimination of each parameter.

RESULTS

RNFL and GCC thickness and ONH and macular VD were significantly lower in PXG patients compared with healthy controls (all, p<0.05). The best discrimination parameter was the average RNFL thickness (AUROC: 0.928). ONH VD AUROC was better than that of macular VD (AUROC: 0.897 and 0.780, respectively). ONH VD AUROC was comparable to RNFL thickness (p<0.001).

CONCLUSIONS

The diagnostic ability of ONH vessel density in PXG appears comparable to that of the structural parameters, RNFL and GCC thickness, obtained with OCT, and may be a valuable tool in clinical practice.

Current understanding of genetics and epigenetics in pseudoexfoliation syndrome and glaucoma

Pseudoexfoliation is a complex, progressive, and systemic age-related disorder. The early stage of deposition of extracellular fibrillar material on ocular and extraocular tissues is termed as pseudoexfoliation syndrome (PEXS). The severe advanced stage is known as pseudoexfoliation glaucoma (PEXG), which involves increased intraocular pressure and optic nerve damage. Through genome-wide association and candidate gene studies, PEX has been associated with numerous genetic risk variants in various gene loci. However, the genetic basis of the disease fails to explain certain features of PEX pathology, such as the progressive nature of the disease, asymmetric ocular manifestation, age-related onset, and only a subset of PEXS individuals developing PEXG. Increasing evidence shows an interplay of genetic and epigenetic factors in the pathology of complex, multifactorial diseases. In this review, we have discussed the genetic basis of the disease and the emerging contribution of epigenetic regulations in PEX pathogenesis, focusing on DNA methylation and non-coding RNAs. Aberrant methylation patterns, histone modifications, and post-transcriptional regulation by microRNAs lead to aberrant gene expression changes. We have reviewed these aberrant epigenetic changes in PEX pathology and their effect on molecular pathways associated with PEX. We have further discussed some possible genetic/epigenetic-based diagnoses and therapeutics for PEX. Although studies to understand the role of epigenetic regulations in PEX are just emerging, epigenetic modifications contribute significantly to PEX pathogenesis and may pave the way for better and targeted therapeutics.

Matrix Metalloproteinases in Glaucoma: An Updated Overview

Matrix metalloproteinases (MMPs) are important regulators of the extracellular matrix (ECM) and are involved in many stages of cellular growth and development. An imbalance of MMP expression is also the basis of many diseases, including eye diseases, such as diabetic retinopathy (DR), glaucoma, dry eye, corneal ulcer, keratoconus. This paper describes the role of MMPs in the glaucoma and their role in the glaucomatous trabecular meshwork (TM), aqueous outflow channel, retina, and optic nerve (ON). This review also summarizes several treatments for glaucoma that target MMPs imbalance and suggests that MMPs may represent a viable therapeutic target for glaucoma.

Genetic background determines severity of Loxl1-mediated systemic and ocular elastosis in mice

Pseudoexfoliation syndrome (PEX) is a systemic, age-related disorder characterized by elastosis and extracellular matrix deposits. Its most significant ocular manifestation is an aggressive form of glaucoma associated with variants in the gene encoding lysyl oxidase-like 1 (LOXL1). Depending upon the population, variants in LOXL1 can impart risk or protection for PEX, suggesting the importance of genetic context. As LOXL1 protein levels are lower and the degree of elastosis is higher in people with PEX, we studied Loxl1-deficient mice on three different genetic backgrounds: C57BL/6 (BL/6), 129S×C57BL/6 (50/50) and 129S. Early onset and high prevalence of spontaneous pelvic organ prolapse in BL/6 Loxl1-/- mice necessitated the study of mice that were <2 months old. Similar to pelvic organ prolapse, most elastosis endpoints were the most severe in BL/6 Loxl1-/- mice, including skin laxity, pulmonary tropoelastin accumulation, expansion of Schlemm's canal and dilation of intrascleral veins. Interestingly, intraocular pressure was elevated in 50/50 Loxl1-/- mice, depressed in BL/6 Loxl1-/- mice and unchanged in 129S Loxl1-/- mice compared to that of control littermates. Overall, the 129S background was protective against most elastosis phenotypes studied. Thus, repair of elastin-containing tissues is impacted by the abundance of LOXL1 and genetic context in young animals.

Investigating the Impact of Sun/UV Protection and Ease of Skin Tanning on the Risk of Pseudoexfoliation Glaucoma: A Mendelian Randomization Study

Purpose

To investigate the potential causal associations between the use of sun/ultraviolet (UV) protection and ease of skin tanning and the risk of pseudoexfoliation glaucoma (PXG) in European populations.

Methods

Single nucleotide polymorphisms (SNPs) associated with the use of sun/UV protection and ease of skin tanning were selected from the UK Biobank genome-wide association study database consisting of 498,751 European participants. SNPs of PXG were obtained from the FinnGen study including 3424 PXG cases and 326,434 controls. Two-sample Mendelian randomization (MR) analyses were performed to assess the association between the use of sun/UV protection and ease of skin tanning and risk of PXG.

Results

Inverse variance weighted regression of genetic susceptibility predicted that both use of sun/UV protection and ease of skin tanning were potentially positively associated with the decreased risk of PXG in the European ancestry (use of sun/UV protection: odds ratio [OR] = 0.47; 95% confidence interval [CI], 0.24-0.92; P = 0.028; ease of skin tanning: OR = 0.81; 95% CI, 0.67-0.97; P = 0.025).

Conclusions

We found genetic evidence supporting a potential causal association between UV protection and a decreased risk of PXG in European population. Further research will help elucidate the underlying mechanisms and promote UV protection for eyes, especially in people with a high risk of PXG.

Evaluation of expression pattern of cellular miRNAs (let-7b, miR-29a, miR-126, miR-34a, miR-181a-5p) and IL-6, TNF-α, and TGF-β in patients with pseudoexfoliation syndrome

Pseudoexfoliation syndrome (PEX) is a critical clinical and biological extracellular matrix systemic disorder. Despite the unknown nature of PEX etiopathogenesis, it is proven to be associated with various genes and factors. The present research focused on analyzing the expression of miR and inflammatory cytokines in PEX. Serum and aqueous humor (AH) were collected prior to cataract surgery or trabeculectomy from 99 participants (64 with PEX glaucoma, and 35 controls). Real-time PCR was used for assessing the expression pattern of some miRNAs namely let-7b, miR-29a, miR-126, miR-34a, and miR-181a-5p. ELISA was carried out to explore the transcription of some inflammatory cytokines such as TGF-β, TNF-α, and IL-6. The indication of our results was a significant enhancement in the expression of let-7, miR-34a, and miR-181a-5p in PEX in contrast to the control group. Notwithstanding a significant suppression in miR-29a, and miR-126 expression levels in PEX in contrast to the control group. Analysis of ROC curve revealed that miR-29a and miR-34a are able to act as useful markers in order to discriminate the PEX group from the PEX negative subjects which were determined as the control group. According to the results obtained, the mean levels of TGF-β, TNF-α, and IL-6 upregulated among PEX subjects in contrast to control samples. In conclusion, our findings indicated that the selected cytokines alongside the selected miRNAs could be introduced as a biomarker panel in the diagnosis of PEX.

Early postoperative visual acuity changes after trabeculectomy and factors affecting visual acuity

PURPOSE

To investigate the early visual acuity (VA) changes that occur after trabeculectomy and their reversal with recovery.

METHOD

Two hundred ninety-two eyes of 292 patients after initial trabeculectomy as a standalone procedure fulfilling the following conditions were included: 1) patients with a postoperative follow-up of at least 3 months; 2) patients with preoperative corrected VA less than 0.5 logMAR equivalent; 3) patients with reliable results of visual field; and 4) patients who had open angle glaucoma. VA and intraocular pressure (IOP) changes during the first 3 months after surgery and factors affecting VA postoperatively at 3 months were investigated.

RESULTS

The mean IOPs (mmHg) after trabeculectomy were significantly lower than preoperatively during the entire period (P < 0.0001). The mean corrected VA for all patients was 0.06 ± 0.17, 0.24 ± 0.38, 0.19 ± 0.26, and 0.14 ± 0.27 preoperatively and at 1 week, 1 month, and 3 months postoperatively, respectively, showing a significant decrease from the preoperative period at all time points (P < 0.0001). VA loss of two or more levels was observed in 13 eyes (4.45%) at 3 months postoperatively. Foveal threshold (FT), shallow anterior chamber (SAC), and choroidal detachment (CD) affected the change in VA before and at 3 months after surgery (P < 0.0001, P = 0.0002, P = 0.0004, respectively). The factors that had significant effects on VA change were FT, SAC, and CD in POAG, FT and hypotonic maculopathy in NTG, and FT in XFG (p < 0.05).

CONCLUSION

The frequency of serious vision loss was 4.45% for two or more levels of vision loss, and early postoperative VA changes after trabeculectomy may not be reversed even 3 months later. VA loss is influenced by preoperative FT, postoperative SAC and CD, but the impact of postoperative complications vary with disease type.

Choroidal thickness measurements of subjects with pseudoexfoliative syndrome and pseudoexfoliative glaucoma: A contralateral eye study

AIM

In this study, we aimed to investigate the peripapillary choroidal thickness (PPCT) and macular choroidal thickness (MCT) in pseudoexfoliation (PEX) syndrome and compare the data of the contralateral eyes according to the presence of biomicroscopic eye involvement and glaucoma.

METHOD

In this cross-sectional case-control study, PPCT and MCT measurements were analyzed in 162 eyes of 81 subjects with PEX syndrome, diagnosed biomicroscopically with the detection of PEX material. The sample included 63 eyes with pseudoexfoliation glaucoma (PG), 49 eyes with visible PEX material alone without glaucoma (PM), 50 fellow eyes without biomicroscopically visible PEX material (F), and 48 eyes of 24 healthy individuals (controls) without any sign of PEX in the detailed ophthalmologic examination. The PEX syndrome group consisted of 25 PM-F, 25 PG-F, 19 PG-PG, and 12 PM-PM eye pairs. The PPCT and MCT values were compared between the eye-pairs of the subjects with the PEX syndrome.

RESULTS

The mean PPCT measurements were 183.3 ± 8.1 µm, 158.5 ± 5.4 µm, 167.8 ± 5.9 µm, and 149.9 ± 5.5 µm for the eyes in the control, F, PM, and PG groups, respectively. The eyes in the PG group had statistically significantly lower measurements than those in the control group (p < 0.01). In the contralateral eye comparison of the subjects with PEX syndrome, no significant difference was found in relation to the mean PPCT and MCT measurements between the PM-F, PG-F, and PG-PG eye pairs (p > 0.05 for all).

CONCLUSION

Although the eye groups with PEX syndrome had lower mean PPCT measurements than the controls, the contralateral eye analysis of the asymmetrically involved eye pairs showed no significant differences.

Evaluating the impact of ocular UV exposure for the development for pseudoexfoliation syndrome in a South Indian population

CLINICAL RELEVANCE

Pathophysiology of pseudoexfoliation syndrome (XFS) can be influenced by environmental factors such as solar exposure/occupational factors and genetic factors.

BACKGROUND

The study aims to assess the association of lifetime ocular UV exposure and its impact on the risk of development of XFS.

METHODS

All eligible subjects underwent a comprehensive ocular examination. XFS was defined as precipitates on the pupillary border, cornea, and angle of anterior chamber or lens in at least one eye without any clinical signs of glaucoma. A standardised questionnaire was administered to assess the lifetime UV exposure. Conjunctival ultraviolet autofluorescence (CUVAF) photography was taken to detect the conjunctival changes with exposure to UV radiation. Ascorbic acid concentration in the aqueous humour was measured.

RESULTS

A total of 404 subjects of which 274 (controls) and 130 (XFS cases) were studied. There were 204 males (50.5%) and 200 females (49.5%).Lifetime UV exposure (OR: 1.14, 95% CI: 1.02-1.30, p: 0.032), CUVAF damage (OR: 1.03, 95% CI: 1.01-1.06, p: 0.008) and outdoor worker (OR: 1.87, 95% CI: 1.18-3.00, p: 0.008) were positively associated with XFS. Usage of spectacles (OR: 0.63, 95% CI: 0.39-0.95, p: 0.030) and ascorbic acid concentration in aqueous (OR: 0.47, 95% CI: 0.23-0.99, p: 0.038) were found to be protective against XFS.

CONCLUSION

Besides genetic factors, environmental factors such as lifetime ocular UV exposure and outdoor work are significantly associated with the risk of XFS. CUVAF can be used as a non-invasive tool to detect preclinical sun damage in outdoor workers.

The Ins and Outs of Clusterin: Its Role in Cancer, Eye Diseases and Wound Healing

Clusterin (CLU) is a glycoprotein originally discovered in 1983 in ram testis fluid. Rapidly observed in other tissues, it was initially given various names based on its function in different tissues. In 1992, it was finally named CLU by consensus. Nearly omnipresent in human tissues, CLU is strongly expressed at fluid-tissue interfaces, including in the eye and in particular the cornea. Recent research has identified different forms of CLU, with the most prominent being a 75-80 kDa heterodimeric protein that is secreted. Another truncated version of CLU (55 kDa) is localized to the nucleus and exerts pro-apoptotic activities. CLU has been reported to be involved in various physiological processes such as sperm maturation, lipid transportation, complement inhibition and chaperone activity. CLU was also reported to exert important functions in tissue remodeling, cell-cell adhesion, cell-substratum interaction, cytoprotection, apoptotic cell death, cell proliferation and migration. Hence, this protein is sparking interest in tissue wound healing. Moreover, CLU gene expression is finely regulated by cytokines, growth factors and stress-inducing agents, leading to abnormally elevated levels of CLU in many states of cellular disturbance, including cancer and neurodegenerative conditions. In the eye, CLU expression has been reported as being severely increased in several pathologies, such as age-related macular degeneration and Fuch's corneal dystrophy, while it is depleted in others, such as pathologic keratinization. Nevertheless, the precise role of CLU in the development of ocular pathologies has yet to be deciphered. The question of whether CLU expression is influenced by these disorders or contributes to them remains open. In this article, we review the actual knowledge about CLU at both the protein and gene expression level in wound healing, and explore the possibility that CLU is a key factor in cancer and eye diseases. Understanding the expression and regulation of CLU could lead to the development of novel therapeutics for promoting wound healing.

Oxidative Stress: A Suitable Therapeutic Target for Optic Nerve Diseases?

Optic nerve disorders encompass a wide spectrum of conditions characterized by the loss of retinal ganglion cells (RGCs) and subsequent degeneration of the optic nerve. The etiology of these disorders can vary significantly, but emerging research highlights the crucial role of oxidative stress, an imbalance in the redox status characterized by an excess of reactive oxygen species (ROS), in driving cell death through apoptosis, autophagy, and inflammation. This review provides an overview of ROS-related processes underlying four extensively studied optic nerve diseases: glaucoma, Leber's hereditary optic neuropathy (LHON), anterior ischemic optic neuropathy (AION), and optic neuritis (ON). Furthermore, we present preclinical findings on antioxidants, with the objective of evaluating the potential therapeutic benefits of targeting oxidative stress in the treatment of optic neuropathies.

Regional variation in the incidence of pseudo-exfoliation in the Andhra Pradesh Eye Disease Study (APEDS)

BACKGROUND

To report the 15-year incidence rate of pseudo-exfoliation (PXF),  PXF glaucoma and regional variation among rural participants in the Andhra Pradesh Eye Disease Study (APEDS) III.

METHODS

This population-based longitudinal study was carried out at three rural study sites. Individuals of all ages who participated at baseline with a mean 15-year follow-up visit were included. Detailed Comprehensive ophthalmic examination was performed on all participants. The main outcome measure was development of PXF during the follow-up period in participants who were phakic in one or both eyes without PXF at baseline.

RESULTS

Among 5395 participants, 5108 (94.6%) met the inclusion criteria. There were 93 (1.82%; 95% confidence interval (CI), 1.47-2.22) cases of incident PXF. Their median baseline age (1st, 3rd quartiles) was 51 (44, 59) years and the male: female ratio was 1.3:1. There was no case of incident PXF in participants aged <30 years at baseline. The incidence rate per 100 person years (95% CI) among all ages and those aged ≥30 years at baseline was 1.73 (1.64-1.82) and 3.73 (3.53-3.93), respectively. PXF material was located on iris as well as anterior surface of lens and it was often bilateral. Participants living in two study sites and increasing age were associated with the incidence of PXF. The 15-year incidence of PXF glaucoma (95% CI) in participants ≥30 years of age at baseline was 0.33% (0.14-0.66).

CONCLUSION

There is significant regional variation in incidence of PXF in south India which warrants further investigation.

Pseudoexfoliation Syndrome-Clinical Characteristics of Most Common Cause of Secondary Glaucoma

Pseudoexfoliation syndrome (XFS) is a condition in which excess material builds up not only in the structures of the anterior chamber but also throughout the body. The frequency of the syndrome varies significantly (0.3-18%) depending on the region and the method of examination. Environmental risk factors for XFS include a large number of sunny days, proximity to the equator, dietary factors such as higher consumption of coffee and tea, long-term alcohol consumption, exposure to UV, and outdoor work. The pathognomonic sign of XFS is the presence of white material on the lens capsule and other anterior chamber components. In addition, a characteristic Sampaolesi line can be observed during gonioscopy. Systemic alterations indicative of XFS have been observed in the extracellular matrix of the eyelid skin, the heart, lungs, liver, kidneys, gallbladder, meninges, and endothelium of the blood vessels. XFS is the most common cause of secondary open-angle glaucoma, which is called pseudoexfoliative glaucoma and is more severe than primary open-angle glaucoma. It is plausible that a combination of environmental factors and genetic alterations promotes the onset of pseudoexfoliation syndrome, which requires additional research.

Dickkopf-1 and ROCK2 upregulation and associated protein aggregation in pseudoexfoliation syndrome and glaucoma

AIMS

The etiology of pseudoexfoliation (PEX), a stress-induced fibrillopathy and a leading cause of secondary glaucoma worldwide, remains limited. This study aims to understand the role of the Wnt antagonist Dickkopf-related protein 1 (DKK1) in PEX pathophysiology and assess its candidature as a biomarker for PEX.

MAIN METHODS

Expression levels of DKK1 and Wnt signaling genes were assayed in the anterior ocular tissues of study subjects by qRT-PCR, Western blotting, and immunohistochemistry. Protein aggregation was studied through Proteostat staining. Role of DKK1 in protein aggregation and regulation of target Wnt signaling genes was elucidated through overexpression and knockdown studies in Human Lens Epithelial cells (HLEB3). Levels of DKK1 in circulating fluids were assayed through ELISA.

KEY FINDINGS

DKK1 upregulation was observed in lens capsule and conjunctiva tissues of PEX individuals compared to controls correlating with an upregulation of the Wnt signaling target, ROCK2. Proteostat staining showed increased protein aggregates in lens epithelial cells of PEX patients. HLE B-3 cells overexpressed with DKK1 showed increased protein aggregates along with upregulation of ROCK2, and knockdown of DKK1 in HLE B-3 cells demonstrated downregulation of ROCK2. Further, ROCK2 inhibition by Y-27632 in DKK1 overexpressed cells showed that DKK1 regulated protein aggregation via ROCK2. Also, increased levels of DKK1 were observed in patients' plasma and aqueous humor compared to controls.

SIGNIFICANCE

This study shows that DKK1 and ROCK2 might play a role in protein aggregation in PEX. Further, elevated levels of DKK1 in aqueous humor serve as a fair classifier of pseudoexfoliation glaucoma.

Long-Term Evaluation of Pseudoexfoliation Syndrome Post-Cataract Extraction

The study aimed to examine the effect of cataract extraction on ophthalmologists' ability to detect pseudoexfoliation (PXF) syndrome. A total of 31 patients admitted for elective cataract surgery were enrolled in this prospective comparative study. Prior to surgery, patients underwent slit-lamp examination and gonioscopy conducted by experienced glaucoma specialists. Subsequently, patients were re-examined by a different glaucoma specialist and comprehensive ophthalmologists. Pre-operatively, 12 patients were diagnosed with PXF on the basis of a Sampaolesi line (100%), anterior capsular deposits (83%), and pupillary ruff deposits (50%). The remaining 19 patients acted as controls. All patients were re-examined 10-46 months post-operatively. Of the 12 patients with PXF, 10 (83%) were correctly diagnosed post-operatively by glaucoma specialists and 8 (66%) by comprehensive ophthalmologists. There was no statistically significant difference in PXF diagnosis. However, detection of anterior capsular deposits (p = 0.02), Sampaolesi lines (p = 0.04), and pupillary ruff deposits (p = 0.01) were significantly lower post-operatively. Diagnosis of PXF is challenging in pseudophakic patients as the anterior capsule is removed during cataract extraction. Therefore, PXF diagnosis in pseudophakic patients relies mainly on the presence of deposits at other anatomical sites, and careful attention to these signs is required. Glaucoma specialists may be more likely than comprehensive ophthalmologists to detect PXF in pseudophakic patients.

Results of Nailfold Videocapillaroscopy in Patients with Pseudoexfoliative Glaucoma

The aim of this study was to evaluate the nailfold videocapillaroscopic examination results from patients with pseudoexfoliative glaucoma (XFG) and to assess the relationship between the results of this examination and the patient's clinical status in the XFG group.

MATERIAL AND METHODS

The studied group consisted of 39 Caucasian patients with XFG and 32 patients in a control group. The patients were classified into two subgroups: the hypertensive pseudoexfoliative glaucoma (hXFG) subgroup and the normotensive pseudoexfoliative glaucoma (nXFG) subgroup. The nailfold videocapillaroscopy (NVC) was performed on all participants. The results of each NVC were classified as having a normal or abnormal pattern.

RESULTS

There was no statistical difference between the results of an abnormal NVC pattern in the study group vs. the control group (p = 0.8773). Microhemorrhages were shown in 30.0% of patients with nXFG vs. the control group (6.25%) (p = 0.0520). Microhemorrhages tended to be more frequent in the XFG group (p = 0.1221). A prevalent number of tortuous capillaries was observed in hXFG patients with advanced glaucomatous neuropathy. Dilatation in the capillaries and microbleedings were observed in the group of patients with lower IOP values. Tortuosity in the capillaries was significantly more frequent in PEXG patients (XFG vs. control: p = 0.0386). No relationships between the results of NVC and age, c/d, BCVA, time of treatment, and visual field defect were found.

CONCLUSIONS

Specific features of NVC examination differentiate nXFG from hXFG patients. Some capillaroscopic features may correlate with the patient's clinical status of XFG.

Optic nerve head vessel density in patients with pseudoexfoliation syndrome/glaucoma: a systematic review and meta-analysis

PURPOSE

Exfoliative material has been shown to accumulate in ocular and systemic tissues. We aimed to perform a systematic review and meta-analysis of the current literature evaluating optic nerve head vessel density (VD) using optical coherence tomography angiography (OCTA) in patients with XFS and XFG.

METHODS

Studies were retrieved from PubMed, Scopus, and Web of Science databases. Studies comparing patients with XFS and/or XFG patients to healthy controls, using the optic nerve head-centred 4.5 × 4.5 mm square OCTA scan protocol were included. Pooled results are presented as standardised mean differences with 95% confidence intervals (CI). Meta-regression analysis was performed between mean difference in circumpapillary VD between XFG and controls and mean pRNFL thickness in patients with XFG.

RESULTS

Fifteen studies with 1475 eyes were included in this review. Whole image VD and circumpapillary VD (cpVD) were significantly decreased in patients with XFS [-0.78(95% Cl: -1.08, -0.47); [-0.55(95% Cl: -0.80, -0.30); respectively] and XFG [-1.85(95% CI: -2.33, -1.36); -1.84 (95% CI: -2.30, -1.39); respectively] compared to healthy controls. Furthermore, pRNFL thickness decreased in patients with XFS [-0.55(95% Cl: -0.72, -0.35)] and XFG [-1.78(95% Cl: -2.21, -1.36)] compared to healthy controls. Meta-regression showed that pRNFL thickness decreased with increasing mean cpVD difference in XFG patients compared to healthy controls.

CONCLUSIONS

OCTA provides non-invasive, objective and reproducible assessment of peripapillary VD and is important for the detection of vasculopathy in patients with XFS or XFG. This study provides strong evidence for decreased cpVD in the eyes of patients with XFS and XFG.

Retinal Nerve Fiber Layer and Ganglion Cell Complex Thickness in Adult Children of Patients With Pseudoexfoliation Glaucoma

PRCIS

The adult children of patients with pseudoexfoliation glaucoma (PXG) had universally lower retinal nerve fiber layer (RNFL) thickness and ganglion cell complex (GCC) thickness values compared with individuals with a negative family history of PXG.

PURPOSE

This study aimed to evaluate RNFL and GCC thicknesses in the adult children of individuals with PXG compared with people without a parental history of PXG.

MATERIALS AND METHODS

This cross-sectional observational study included 40 eyes of 40 adults with confirmed parental history of PXG and 40 eyes of 40 healthy adults with no parental history of PXG. RNFL and macular GCC thicknesses were measured by spectral-domain optical coherence tomography (Nidek RS-3000 Advance) and compared between the groups. All subjects also underwent visual field testing (program 30-2 of the Humphrey Field Analyzer), and their mean deviation and pattern SD values were compared.

RESULTS

Compared with adults without parental PXG, those with a parental history of PXG had significantly lower RNFL thickness overall (mean 98.2 vs 109.5 µm) and in all quadrants (inferior, superior, nasal, and temporal) ( P <0.001 for all). They also had significantly lower GCC thickness overall (mean 97.9 vs 109.4 µm) and in both hemispheres (superior and inferior) ( P <0.001 for all). There was no significant difference between the groups in terms of mean deviation or pattern SD values ( P >0.05).

CONCLUSION

PXG in a parent was associated with significantly thinner RNFL and GCC compared with those with no history of PXG in a parent. Longer follow-up and prospective controlled clinical studies are needed to evaluate whether these findings may serve as an early indicator of glaucoma in the adult children of known PXG patients.

Systemic immuno-inflammatory index in patients with pseudoexfoliation syndrome and pseudoexfoliative glaucoma

Background

In recent years, the role of some hematological parameters used as chronic inflammation markers in the pathogenesis of many ocular and systemic diseases has been investigated. For ocular diseases such as uveitis, keratoconus, and retinal vein occlusion, the neutrophil/lymphocyte ratio (NLR) and systemic immune-inflammatory index (SII) have been reported to be useful inflammatory biomarkers. It has also been reported that low-grade chronic inflammation plays a role in the formation of pseudoexfoliation.

Objective

To evaluate the NLR, SII, and platelet-lymphocyte ratio (PLR) in patients with pseudoexfoliation syndrome (PEXS) and pseudoexfoliative glaucoma (PEXG).

Design

This was a retrospective case-control study.

Methods

This study evaluated the clinical and laboratory data of 34 patients with PEXS, 33 patients with PEXG, and 33 control patients. Detailed eye examination notes in patient files and blood count measurements were recorded.

Results

SII values were the highest in the PEXS group, followed by the PEXG and control groups (582.01 ± 339.9, 478.14 ± 211.7, and 413.98 ± 129.5, respectively) (p = 0.043). In paired comparisons, the SII values of the PEXS group were significantly higher than the control group (p = 0.011). The mean NLR rate was highest in the PEXS group, followed by the PEXG and the control groups (2.46 ± 1.6, 2.17 ± 0.8, and 1.69 ± 0.4, respectively) (p = 0.023). In paired comparisons, the mean NLR levels were higher in the PEXS and the PEXG groups than in the control group (p = 0.03 and p = 0.01, respectively). There was no significant difference between the groups in terms of PLR. According to receiver operating characteristic curve analysis, the optimal cut-off value for estimating PEXS was found as >449.4 for SII and 1.78 for NLR (p = 0.011 and p = 0.031, respectively).

Conclusions

In PEXS patients, both SII and NLR were significantly higher, albeit in a small group of patients, and SII may be a helpful and supportive parameter for NLR in risk estimation in these patients. There was a statistically significant difference only in NLR in patients with PEXG when compared with the control group. However, these results need to be supported by future longitudinal and larger studies to identify any possible link between hematological inflammatory markers and pseudoexfoliation.

Single nucleotide polymorphisms in LOXL1 as biomarkers for progression of exfoliation glaucoma in Sweden

PURPOSE

Exfoliation glaucoma is a common and aggressive type of glaucoma with high prevalence in Scandinavia. The aim of this study was to elucidate whether the allele frequencies of two single nucleotide polymorphisms (SNPs) located in LOXL1 were associated with the progression of exfoliation glaucoma in Swedish patients.

METHODS

In this non-randomised cohort study, we enrolled patients with exfoliation glaucoma, and they performed at least five reliable visual field tests. Blood samples were collected, and genotyping was performed using competitive allele-specific PCR genotyping. Glaucoma progression was evaluated using the guided glaucoma progression analysis (GPA), mean deviation (MD) difference and rate of progression (ROP). In addition, associations between allele frequencies and glaucoma progression were tested using logistic regression for GPA and linear regression for MD and ROP.

RESULTS

We enrolled a total of 130 patients in the study. The general genetic model showed statistical significance for LOXL1_rs2165241 (p = 8 × 10^-7 , Fisher's exact test) and LOXL1_rs1048661 (p = 2 × 10^-6 , Fisher's exact test). Regression analyses using an additive genetic model showed significant values for LOXL1_rs2165241SNP in relation to GPA, MD and ROP as outcomes (p = 1.8 × 10^-4 , 4 × 10^-2 , 6 × 10^-4 ) and for LOXL1_rs1048661 SNP in relation to GPA, MD and ROP (p = 7 × 10^-5 , 8 × 10^-3 , 2 × 10^-4 ).

CONCLUSIONS

This was the first study to show an association of the SNPs LOXL1_rs2165241 and LOXL1_rs1048661 with the progression of exfoliation glaucoma. Further large-scale studies are required to verify these findings.

Lysyl oxidase-like 1 deficiency alters ultrastructural and biomechanical properties of the peripapillary sclera in mice

•

Lysyl oxidate-like 1 knockout (Loxl1^-/-) mice have decreased vision without elevated intraocular pressure.

•

Loxl1^-/- mice exhibit biometric changes of the anterior segment of the eye.

•

Loxl1^-/- mice have altered elastin and collagen structure in peripapillary sclera.

•

Structural alternations of peripapillary sclera correlate with its increased stiffness in Loxl1^-/- mice.

Lysyl oxidase-like 1 encoded by the LOXL1 gene is a member of the lysyl oxidase family of enzymes that are important in the maintenance of extracellular matrix (ECM)-rich tissue. LOXL1 is important for proper elastic fiber formation and mice lacking LOXL1 (Loxl1^−/−) exhibit systemic elastic fiber disorders, such as pelvic organ prolapse, a phenotype associated with exfoliation syndrome (XFS) in humans. Patients with XFS have a significant risk of developing exfoliation glaucoma (XFG), a severe form of glaucoma, which is a neurodegenerative condition leading to irreversible blindness if not detected and treated in a timely fashion. Although Loxl1^−/− mice have been used extensively to investigate mechanisms of pelvic organ prolapse, studies of eyes in those mice are limited and some showed inconsistent ocular phenotypes. In this study we demonstrate that Loxl1^−/− mice have significant anterior segment biometric abnormalities which recapitulate some human XFS features. We then focused on the peripapillary sclera (PPS), a critical structure for maintaining optic nerve health. We discovered quantitative and qualitive changes in ultrastructure of PPS, such as reduced elastic fibers, enlarged collagen fibrils, and transformed collagen lamella organization detected by transmission electron microscopy (TEM). Importantly, these changes corelate with altered tissue biomechanics detected by Atomic Force Microscopy (AFM) of PPS in mice. Together, our results support a crucial role for LOXL1 in ocular tissue structure and biomechanics, and Loxl1^−/− mice could be a valuable resource for understanding the role of scleral tissue biomechanics in ocular disease.

Towards preventing exfoliation glaucoma by targeting and removing fibrillar aggregates associated with exfoliation syndrome

Exfoliation syndrome presents as an accumulation of insoluble fibrillar aggregates that commonly correlates with age and causes ocular complications, most notably open-angle glaucoma. Despite advances in understanding the pathogenesis and risk factors associated with exfoliation syndrome, there has been no significant progress in curative pharmacotherapy of this disease. It is thought that the ability to target the fibrillar aggregates associated with exfoliation may offer a new therapeutic approach, facilitating their direct removal from affected tissues. Phage display techniques yielded two peptides (LPSYNLHPHVPP, IPLLNPGSMQLS) that could differentiate between exfoliative and non-affected regions of the human lens capsule. These peptides were conjugated to magnetic particles using click chemistry to investigate their ability in targeting and removing exfoliation materials from the anterior human lens capsule. The behavior of the fibrillar materials upon binding to these magnetic particles was assessed using magnetic pins and rotating magnetic fields of various strengths. Ex vivo studies showed that the magnetic particle-peptide conjugates could generate enough mechanical force to remove large aggregates of exfoliation materials from the lens capsule when exposed to a low-frequency rotating magnetic field (5000 G, 20 Hz). Biocompatibility of targeting peptides with and without conjugated magnetic particles was confirmed using MTT cell toxicity assay, live/dead cell viability assay, and DNA fragmentation studies on primary cultured human trabecular meshwork cells. This is a novel, minimally invasive, therapeutic approach for the treatment of exfoliation glaucoma via the targeting and removal of exfoliation materials that could be applied to all tissues within the anterior segment of the eye.

Exfoliation Syndrome and Exfoliation Glaucoma in the Navajo Nation

(1) Background: Exfoliation syndrome (XFS) is a common cause of secondary open angle glaucoma. In 1971, Faulkner et al. estimated the prevalence of XFS among 50 Navajo Nation residents as 38%. Given that XFS can cause irreversible blindness secondary to glaucoma (XFG), this study aims to identify the current prevalence of XFS among Navajo Nation residents within the Four Corners region of the U.S. (2) Methods: A retrospective chart review was conducted from 2016 to 2021 for patients aged 18 and older. All patients with XFS or XFG diagnosed by slit lamp exam were identified through chart review. (3) Results: Of the 1152 patient charts available for review, eight patients (11 eyes) were diagnosed with XFS with three patients (4 eyes) demonstrating concomitant XFG. Within this XFS population, 50% of the patients identified as male, with a mean age of 73 years. The overall prevalence of XFS was 0.7% and the overall prevalence of XFG was found to be 0.26%. The rate of XFG among patients with XFS was 37.5%. (4) Conclusion: Compared to Faulkner's study of Navajo Nation residents in 1971, our findings show a considerably lower prevalence of XFS at 0.7%. We present the largest study to date of XFS among this population.

Peripapillary and fovea avascular zone optical coherence tomography angiography parameters in exfoliation glaucoma versus primary open-angle glaucoma versus healthy eyes

Purpose

To examine the differences in the peripapillary vascular parameters and foveal-avascular-zone (FAZ) vascularity parameters between primary open-angle-glaucoma (POAG) patients versus exfoliation-glaucoma (XFG) patients versus healthy subjects.

Methods

This is cross-sectional study and a comparative clinical study. POAG and XFG patients and healthy subjects underwent a comprehensive ophthalmic examination, including visual field optical coherence tomography (OCT) and OCT angiography (OCTA) of the optic disc and FAZ. Differences in peripapillary vessel density (VD), perfusion density (PD), and FAZ area and circularity were examined between all groups, as well as correlations between clinical parameters and vascularity parameters for each glaucoma group.

Results

A total of 109 subjects (one eye for each patient) were analyzed, including 45 with POAG, 30 with XFG, and 34 controls. The average peripapillary VDs were the lowest among the XFG patients and the highest among the controls (P < 0.05, ANOVA). The average peripapillary PD of the central ring was the lowest in the XFG group and the highest in the control group (P = 0.02, ANOVA). A significant negative correlation was found between the average peripapillary VDs and PDs of the inner ring and full ring and disease severity of the POAG patients. There was a significant positive correlation between the average peripapillary PDs of the central rings and full ring and the central macular thickness of the XFG patients (P < 0.01 and P < 0.04, respectively, Pearson correlation).

Conclusion

The peripapillary vascular parameters of the POAG and XFG patients were lower compared to those of normal participants. A correlation between clinical characteristics of POAG and XFG patients and PD was found. This may hint to a vascular mechanism in glaucoma either primary or secondary to intra-ocular pressure/OAG damage.

Socio-Demographic, lifestyle and eye-related factors associated with quality of life Among people with glaucoma in Serbia

PURPOSE

The purpose of this study was to examine socio-demographic, lifestyle and ophthalmological factors associated with poorer Vision Related Quality of Life (VRQoL) in people with glaucoma.

METHODS

This cross-sectional study included 306 consecutive patients with glaucoma who presented for regular check-ups at the referral center in Belgrade (Serbia) from August 2015 to September 2016. The diagnosis of glaucoma was based on the glaucomatous disc cupping and reproducible visual field impairment on one or both eyes. Quality of life was examined using the validated Glaucoma Quality of Life-15 (GQL-15) and the National Eye Institute Visual Function Questionnaire 25 (NEI VFQ 25).

RESULTS

A series of adjusted linear regression models showed that glaucoma patients with higher educational attainment, who were employed and still driving had better VRQoL. Worse visual acuity and visual field defect, being in later glaucoma stages, having lower intraocular pressure, having two laser interventions as well as having pseudo-exfoliative glaucoma was associated with worse VRQoL. Intake of fewer medications and having had no trabeculectomies on better eye as well as taking less drops per day on worse eye were associated with better VRQoL.

CONCLUSIONS

Several socio-demographic, lifestyle and ocular factors can impact VRQoL in glaucoma patients. Identifying people who are at risk of having worse VRQoL could allow for earlier interventions, such as changes in therapy, undergoing surgery, use of mobility aids etc.

Hearing Loss in Exfoliation Syndrome: Systematic Review and Meta-Analysis

OBJECTIVE

To determine if exfoliation syndrome (XFS) is associated with hearing loss (HL) or vestibular dysfunction.

DATA SOURCES

PubMed, Scopus, CINAHL, and Cochrane Library through April 1, 2022.

REVIEW METHODS

Two reviewers independently screened abstracts, selected articles for inclusion, and extracted data. Studies included for qualitative analysis conducted audiometric, tympanometric, or vestibular evaluations on all subjects.

RESULTS

Twenty-one publications (1148 patients with XFS and 1212 controls) were included in the systematic review, and 16 publications (968 patients with XFS and 1147 controls) in the meta-analysis. Greater severity of HL was seen for patients with XFS compared to controls across all frequencies (odds ratio [OR] 8.8 [7.3-10.2]). Patients with XFS were more likely to have moderate to profound sensorineural HL (OR 1.8 [1.3-2.5]), and less likely to have none to mild HL (OR 0.34 [0.17-0.67]) or no HL (OR 0.37 [0.28-0.50]). Three studies found patients with XFS had lower tympanometric peaks. Two studies found that abnormal vestibular testing results could be more common for patients with XFS.

CONCLUSIONS

HL is associated with XFS. A sensorineural component to HL is confirmed, and mixed HL is possible. Given the high prevalence and infrequent diagnosis of XFS, the authors hypothesize that the current understandings of presbycusis might be improved by further investigation in XFS. Laryngoscope, 2022.

Short-term surgical outcomes of twin-site combined phaco-emulsification and mitomycin-C augmented trabeculectomy in pseudo-exfoliation glaucoma versus primary open-angle glaucoma

Purpose

To compare the short-term outcomes of combined phaco-emulsification with posterior chamber intra-ocular lens and mitomycin augmented trabeculectomy in patients with pseudo-exfoliation glaucoma (PXFG) versus primary open-angle glaucoma (POAG).

Methods

A total of 144 eyes of 144 patients were enrolled in this prospective interventional comparative study, 72 each of which had PXFG and POAG, respectively. All patients underwent twin-site combined phaco-trabeculectomy at a tertiary eye center in India between December 2017 and December 2018 and were followed up for a period of 12 months. The main outcome measures were intra-ocular pressure (IOP), best corrected visual acuity (BCVA), total surgical time, rate of intra-operative and post-operative complications, and the number of ocular hypotensive medications needed. Success rates were determined via Kaplan-Meier survival analysis.

Results

The mean age was 63.9 ± 7.9 years in the POAG group and 66.4 ± 6.8 years in the PXFG group (P - 0.04). The baseline BCVA, IOP, and cup-disc ratio were comparable between two groups. Intra-operative complications and post-operative outcomes were comparable between the two groups. There was a significant drop in anti-glaucoma medications in both groups. Six patients, three (4.2%) in each group, were lost to follow-up after 6 months. Three patients (4.2%) in PXFG needed additional glaucoma intervention for controlling IOP, one patient needed a non-valved glaucoma drainage device, and two patients required diode cyclo-photocoagulation within the follow-up period.

Conclusion

Patients with PXFG had a longer surgical time than POAG. Similar success and complication rates were observed following combined twin-site phaco-trabeculectomy in both POAG and PXFG at 1 year. Combined glaucoma surgery resulted in good IOP control, improvement in BCVA, and lower requirement of ocular hypotensives in both the groups.

Risk factors for early-onset exfoliation syndrome

Although exfoliation syndrome (XFS) is an age-related, late-onset disease, early-onset XFS has been reported, and its associated factors remain unknown. In this study, we investigated the clinical features and risk factors of early-onset XFS. The participants were divided into two groups according to age at the time of XFS diagnosis: early-onset (< 60 years) or late-onset (≥ 70 years) group. Among the 302 eyes of 240 patients with XFS, the early-onset group included 41 eyes (14%) of 33 patients, and the late-onset group included 163 eyes (54%) of 126 patients; the mean age was 54.8 ± 5.0 and 76.6 ± 4.9 years, respectively (p < 0.001). All eight cases diagnosed with XFS at the earliest age, ranging from 36 to 52 years, underwent trabeculectomy before the diagnosis of XFS. Multivariable logistic regression analysis showed that a history of trabeculectomy (odds ratio [OR] = 11.435, p < 0.001), presence of iridectomy (OR = 11.113, p < 0.001), and longer axial length (OR = 2.311, p = 0.003) were significantly associated with the development of early-onset XFS. Collectively, patients with early-onset XFS were more likely to have undergone trabeculectomy and have more axial myopia compared with those with late-onset XFS. These findings suggest that surgical trauma compromising the blood-aqueous barrier may trigger early manifestation of XFS.

Acoustic Manipulation of Intraocular Particles

Various conditions cause dispersions of particulate matter to circulate inside the anterior chamber of a human eye. These dispersed particles might reduce visual acuity or promote elevation of intraocular pressure (IOP), causing secondary complications such as particle related glaucoma, which is a major cause of blindness. Medical and surgical treatment options are available to manage these complications, yet preventive measures are not currently available. Conceptually, manipulating these dispersed particles in a way that reduces their negative impact could prevent these complications. However, as the eye is a closed system, manipulating dispersed particles in it is challenging. Standing acoustic waves have been previously shown to be a versatile tool for manipulation of bioparticles from nano-sized extracellular vesicles up to millimeter-sized organisms. Here we introduce for the first time a novel method utilizing standing acoustic waves to noninvasively manipulate intraocular particles inside the anterior chamber. Using a cylindrical acoustic resonator, we show ex vivo manipulation of pigmentary particles inside porcine eyes. We study the effect of wave intensity over time and rule out temperature changes that could damage tissues. Optical coherence tomography and histologic evaluations show no signs of damage or any other side effect that could be attributed to acoustic manipulation. Finally, we lay out a clear pathway to how this technique can be used as a non-invasive tool for preventing secondary glaucoma. This concept has the potential to control and arrange intraocular particles in specific locations without causing any damage to ocular tissue and allow aqueous humor normal outflow which is crucial for maintaining proper IOP levels.