Ultrasound biomicroscopy of zonular anatomy in clinically unilateral exfoliation syndrome

Evaluation of changes of anterior segment parameters in patients with pseudoexfoliation syndrome after cataract surgery using anterior segment optical coherence tomography

The aim of the study was to compare the anterior segment parameters after cataract surgery in pseudoexfoliation syndrome (PEX) and control eyes. We conducted a prospective comparative study of 36 eyes (PEX group), 16 eyes (PEXG group) and 46 eyes (control group) of 98 patients after phacoemulsification with intraocular lens implantation. Before surgery, 1 week, 1 month and 3 months postoperatively, anterior chamber parameters were evaluated by swept source anterior segment optical coherence tomography (AS-OCT). Anterior chamber depth (ACD), angle opening distance (AOD500/750), trabecular-iris space area (TISA500/750), trabecular-iris angle (TIA500/750) and lens vault (LV) were assessed at each study visit. Preoperatively, ACD, AOD500/750 and TISA500/750 were significantly smaller, while LV was significantly greater in PEX and PEXG eyes than in controls. 3 months postoperatively all irido-corneal parameters and ACD were significantly greater in all study groups without intergroup differences. ACD and LV significantly increased in PEX group between 1 and 3 months after surgery while being stable in control group. Relative increases in ACD, AOD500, TISA750, TIA500/750 were significantly higher in PEX and PEXG groups than in controls. Our study finds that ACD and iridocorneal parameters in AS-OCT demonstrated significantly greater relative increases 3 months after phacoemulsification in PEX and PEXG groups than in control eyes. Significantly greater deepening of anterior chamber and opening of the irido-corneal angle may be a reason for different refractive outcomes and IOP control in patients with PEX and PEXG after routine cataract surgery.

Assessment of Zonular Integrity in Phakic Eyes Following Pars Plana Vitrectomy Using Ultrasound Biomicroscopy: A Prospective Paired Eye Comparative Study

PURPOSE

To assess zonular integrity in phakic patients post vitrectomy using ultrasound biomicroscopy (UBM).

DESIGN

Prospective, comparative, nonrandomized, double-masked, paired eye study.

METHODS

We used ultrasound biomicroscopy (UBM) to evaluate phakic patients with a history of unilateral pars-plana vitrectomy.

INCLUSION CRITERIA

(1) phakic patients with history of pars plana vitrectomy in one eye as the only procedure; (2) normal unoperated fellow eye; and (3) complete gas or air resolution from the vitreous cavity at the time of UBM assessment.

EXCLUSION CRITERIA

(1) monocular patients; (2) history of intraoperative lenticular trauma; (3) the use of silicone oil tamponade; (4) history of trauma or pseudoexfoliation in either eye; (5) history of other ocular conditions that can affect the integrity of zonules, such as uveitis or ectopia lentis; (6) eyes with extreme myopia or long axial length (> -8.00 D or >30.0 mm); (7) history of intravitreal injection in either eye; (8) age <18 years.

TECHNIQUE

A high-frequency (50 MHz) UBM device was used by a masked technician to obtain radial section images from zonular bundles at 8 different clock positions. Image quality was assessed in real time, captured, and saved. Two experienced masked observers (H.C. and C.B.) then assessed the quality of the images and graded the zonular findings. Only patients with adequate studies have been included. A unique grading system that was specifically devised for this study was used as the following: (0) clear, well-defined zonule(s); (1) uneven, disrupted zonules or stretched zonules; and (2) extensive loss of zonules. Each clock hour was graded according to this system and the total score was then calculated for each eye. In the primary outcome, 2 main groups were analyzed: vitrectomized eyes and healthy contralateral nonvitrectomized eyes. The mean total UBM score (TUS) from each group was compared and analyzed.

RESULTS

Thirty-five patients were recruited into this study. Eleven patients were male and 24 were female. The mean age was 66.3 years. Thirty patients had vitrectomy for vitreomacular interface disorders (either macular hole or epiretinal membrane), 1 patient had vitreous hemorrhage and the remaining 4 patients had rhegmatogenous retinal detachments. With regard to tamponade agents, SF6 was used in 21 (60%) patients, air in 9 (26%) patients, and C3F8 in 5 (14%) patients. The mean TUS in the vitrectomized eyes was 2.28 (SD 1.83) vs 2.24 (SD 1.77) in the nonvitrectomized eyes (P = .9531). Overall, in the comparative analysis of mean scores based on 2 graders' assessments for each clock position in vitrectomized and nonvitrectomized eyes, there were no significant differences noted between the groups.

CONCLUSION

This study found no evidence for a difference in the mean total UBM score in eyes following vitrectomy when compared to their contralateral healthy, nonvitrectomized eyes. This likely indicates that vitrectomy may not affect the integrity of zonules in phakic patients, at least for patients with vitreomacular interface disorders undergoing uncomplicated surgery.

Repeatability and reproducibility of anterior lens zonule length measurement using ArcScan Insight 100 very high-frequency ultrasound

OBJECTIVES

This study aimed to evaluate the intra-examiner repeatability and inter-examiner reproducibility in lens zonular length measurements using very high-frequency digital ultrasound (Insight 100).

METHODS

Two examiners performed ultrasound imaging independently in each subject. The length of temporal and nasal zonules were then measured with a built-in software. Coefficient of variations (CVs) of the three repeated measurements were used to determine intra-examiner variances. Inter-examiner reproducibility was evaluated using intraclass correlation coefficients (ICCs) and the Bland-Altman method.

RESULTS

40 eyes of 40 subjects (14male and 26female; mean age 23.9 ± 2.4 years) were included in the study. The CVs for intra-examiner measurement were 2.74% temporally and 4.32% nasally for Examiner 1, and were 1.96% temporally and 1.75% nasally for Examiner 2. For inter-examiner reproducibility, all ICCs were above 0.9. However, there were significant differences between the two examiners in temporal zonular length measurements (p = 0.001), and the differences mainly came from measuring the zonular length manually (p = 0.001) rather than recording images (p = 0.480). No significant differences were found between two measurements by the same examiner after one month (all p > 0.05, all ICCs＞0.8).

CONCLUSION

The Insight 100 device can be used to measure the length of anterior lens zonule with relatively good repeatability and reproducibility.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov identifier is NCT05657951.

Evaluation of Anterior Segment Parameters in Pseudoexfoliation Disease Using Anterior Segment Optical Coherence Tomography

PURPOSE

To compare anterior segment and angle parameters between pseudoexfoliation syndrome (PEX) and PEX glaucoma (PEXG) and normal control subjects using anterior segment optical coherence tomography (AS-OCT) imaging.

DESIGN

Cross-sectional study.

METHODS

One hundred and two subjects with PEXG, PEX, and normal eyes as the control group were recruited from an academic referral institution. All subjects underwent a complete ophthalmologic examination, axial length measurement, and AS-OCT imaging. Anterior segment and angle parameters were evaluated.

RESULTS

After excluding 4 eyes because of poor imaging of the scleral spur, data from 34 eyes with PEXG, 33 eyes with PEX, and 31 eyes of normal control subjects were analyzed. Anterior chamber depth was significantly shallower in eyes with PEXG compared with eyes of control subjects (P < .001). The differences in anterior chamber angle parameters (AOD500, AOD750, TISA500,and TISA750) were significant among study groups, with lower values in the PEXG group compared with the PEX and control subject groups. Lens vault (mean [mm]±SD) was higher in the PEXG (0.46 ±0.21) and PEX (0.427 +0.28) groups compared with the control group (0.305+ 0.20).

CONCLUSIONS

PEXG eyes have the narrowest anterior chamber angle parameters. There is a progressive decrease in angle parameters from control subjects to the PEX group to the PEXG group. Narrow anterior chamber angle and anterior chamber depth may have a role in the progression of PEX to PEXG. Detection of narrow angle in these patients may help clinicians manage the disease more properly.

Zonular defects in loxl1-deficient zebrafish

BACKGROUND

To investigate the roles of the lysyl oxidase-like 1 (loxl1) gene in zebrafish eye development and the potency of loxl1 deficiency in mimicking the ocular manifestations of exfoliation syndrome (XFS).

METHODS

CRISPR/Cas9 technology was used to generate a frameshift coding deletion in zebrafish loxl1. Expression profiles and ocular manifestations of the wildtype, heterozygous mutant (loxl1^+/- ) and homozygous mutant (loxl1^-/- ) zebrafish were analysed in a range of developmental stages from zebrafish larvae to dissected adult zebrafish eyes.

RESULTS

The loxl1 deficiency caused zonular bundling disorders in juvenile zebrafish and accumulation of pearl-like particles adhering to the adult zebrafish zonule. The bundles appeared to lack form and were thinner in both loxl1^+/- and loxl1^-/- zebrafish compared with the wildtype (p < 0.01 for all Bonferroni post-hoc analyses). The zonule of loxl1^-/- zebrafish appeared stretched, ragged and torn, with isolated fibres also detected. The particles in loxl1^-/- zebrafish were more numerous (counts: 92.33 ± 10.02/100 μm² vs. 58.33 ± 5.03/100 μm² , p = 0.006), but smaller in size (diameter: 0.21 ± 0.03 μm vs. 0.43 ± 0.04 μm, p = 0.002) compared with those in loxl1^+/- . Transmission electron microscopy revealed thinning or even loss of elastic lamina in loxl1^+/- Bruch's membrane (BM) (thickness of elastic lamina: 92.94 ± 18.19 nm in the wildtype vs 35.65 ± 14.76 nm in loxl1^+/- , p = 0.003). The breakage of BM was observed in loxl1^-/- .

CONCLUSIONS

The loxl1^-/- zebrafish is a promising animal model of XFS zonular pathology.

Characteristics of Patients with Pseudoexfoliation Syndrome at a Tertiary Eye Care Center in Jordan: A Retrospective Chart Review

PURPOSE

To present the clinical profile of patients with pseudoexfoliation (PXF) and describe its association with pseudoexfoliation glaucoma and cataract surgery complications at a university hospital in Jordan.

METHODS

Electronic chart search was performed among patients aged ≥ 50 years who attended the Jordan University Hospital between January 2015 and March 2018, to identify patients with pseudoexfoliation. Data derived from history and ophthalmic examination regarding laterality of pseudoexfoliation, presence of glaucoma, glaucoma surgery, cataract, cataract surgery, lens instability, and complications of cataract surgery were collected and analyzed.

RESULTS

Of 19,753 patient records searched, 962 (477 male and 485 female) had PXF (4.9%). The mean (SD) age was 71.8 (8.1) years. Pseudoexfoliation was unilateral in 539 patients (56.0%). The mean age of patients with clinically bilateral PXF was significantly higher than those with clinically unilateral PXF (p = 0.001). Pseudoexfoliation glaucoma was present in 237 of 962 (25.4%) patients with PXF and was significantly associated with clinically bilateral PXF (p < 0.001) and male gender (p = 0.001). In 454 (48.9%) patients (638 eyes) who underwent cataract surgery, there was no statistically significant difference in the rate of intraoperative complications between PXF eyes and the fellow eyes of clinically unilateral PXF eyes (p = 0.37), or between patients with clinically unilateral and clinically bilateral PXF (p = 0.78).

CONCLUSION

In this large hospital-based study, the frequency of PXF was 4.9%. Glaucoma was present in one fourth of patients and was significantly associated with clinically bilateral PXF and male gender. Cataract surgery complication rates were not statistically different between PXF and the fellow eyes of clinically unilateral PXF eyes. Surgeons need to be aware of the potential increased risk of intraoperative complications in both groups.

Monitoring and management of the patient with pseudoexfoliation syndrome: current perspectives

Pseudoexfoliation syndrome (PES) is a complex and age-related systemic disorder characterized by the progressive accumulation and granular deposition of pseudoexfoliative material in various intraocular and extraocular tissues. The diagnosis of PES is so important because it is a major risk factor for complications during cataract surgery and the most frequent cause of secondary glaucoma. In addition to ocular complications, PES is related with numerous systemic abnormalities, for which the list is growing steadily. Therefore, management and monitoring of patients with PES are crucial. The aim of this paper was to review current perspectives on monitoring patients with PES and addressing management of ocular and systemic associations of this clinically important and biologically fascinating disease.

Anterior segment imaging in glaucoma: An updated review

Anterior segment imaging allows for an objective method of visualizing the anterior segment angle. Two of the most commonly used devices for anterior segment imaging include the anterior segment optical coherence tomography (AS-OCT) and the ultrasound biomicroscopy (UBM). AS-OCT technology has several types, including time-domain, swept-source, and spectral-domain-based configurations. We performed a literature search on PubMed for articles containing the text “anterior segment OCT,” “ultrasound biomicroscopy,” and “anterior segment imaging” since 2004, with some pertinent references before 2004 included for completeness. This review compares the advantages and disadvantages of AS-OCT and UBM, and summarizes the most recent literature regarding the importance of these devices in glaucoma diagnosis and management. These devices not only aid in visualization of the angle, but also have important postsurgical applications in bleb and tube imaging.

[PEX syndrome. Clinical diagnosis and systemic manifestations]

As a result of demographic changes pseudoexfoliation (PEX) syndrome, an age-related systemic disorder of the extracellular matrix, will become an increasingly important issue in clinical practice. Apart from its well-known association with cataract and glaucoma, PEX syndrome predisposes to a broad spectrum of spontaneous and surgical ocular complications due to characteristic alterations of all anterior segment tissues. In view of the high risk of glaucoma development and potential complications during cataract surgery, an accurate and early diagnosis of PEX syndrome is of considerable clinical relevance. Since the characteristic central PEX deposits are lacking in up to 50 % of patients, a reliable diagnosis requires pupillary dilation. Early stages of the disease may be recognized on the basis of subtle alterations of the lens surface in addition to poor pupillary dilation and pigment-related signs including pigment dispersion and peripupillary atrophy. Any asymmetric clinical signs, e.g., regarding pupil width, pigmentation, cataract and intraocular pressure, should alert the ophthalmologist to the potential presence of PEX syndrome. Although the description of PEX syndrome as a systemic disorder of the extracellular matrix associated with the deposition of PEX material in the skin, blood vessel walls and various organ systems dates back to the early 1990s, a causal relationship between the abnormal material deposits and systemic diseases has not yet been clearly established. A growing number of smaller studies have found suggestive evidence for associations between PEX syndrome and cardiovascular/cerebrovascular diseases. The current evidence, however, is ambiguous and requires further investigation through multicenter or population-based, prospective, randomized clinical studies.

Anterior segment imaging in glaucoma

Anterior segment imaging allows objective assessment of the anterior segment of the eye, particularly the anterior chamber angle. Both qualitative and quantitative analyses are possible and aid in detecting and managing closed-angle and open-angle mechanisms in various forms of glaucoma. This review focuses primarily on anterior segment optical coherence tomography and ultrasound biomicroscopy, with emphasis on principles of technology, commercially available devices, and clinical applications in glaucoma with potential advantages and disadvantages of each technology.

Changing trends of imaging in angle closure evaluation

Primary angle closure glaucoma (PACG) is a significant cause of visual disability worldwide. It predominantly affects the Eastern and South Asian population of the world. Early detection of anatomically narrow angles is important, and the subsequent prevention of visual loss from PACG depends on an accurate assessment of the anterior chamber angle (ACA). Gonioscopy has given way to modern day imaging technologies such as ultrasound biomicroscopy (UBM) and more recently, anterior segment optical coherence tomography (AS-OCT). Ultrasound biomicroscopy provides objective, high-resolution images of anterior segment anatomy, including the cornea, iris, anterior chamber, anterior chamber angle, and ciliary body. Optical coherence tomography (OCT) is a noncontact optical signal acquisition and processing device that provides magnified, high-resolution cross-sectional images of ocular tissues. Recent technological advances towards three-dimensional visualization broadened the scope of AS-OCT in ophthalmologic evaluation. Optical coherence tomography systems use low-coherence, near-infrared light to provide detailed images of anterior segment structures at resolutions exceeding that of UBM. This paper summarizes the clinical application of UBM and OCT for assessment of anterior segment in glaucoma.

Ultrasound biomicroscopy findings in fireworks-related blunt eye injuries

PURPOSE

To present ultrasound biomicroscopic (UBM) findings and their clinical correlations in people with optically hazy media after injury at the Persian Wednesday Eve fireworks festival.

METHODS

Ultrasound biomicroscopy was performed on a series of 32 eyes with severe closed-globe injuries by P40 ultrasound biomicroscope.

RESULTS

The median age of the participants was 19 years, and 81.3% were male. All but one had gross hyphema. Seventy-five percent had an extension of the injury (at least) to Birmingham Eye Trauma Terminology zone II. Ultrasound biomicroscopy detected 3 more iridodialyses and 10 more cyclodialyses in addition to the respective 5 and 3 that were diagnosed clinically. Ten cases of angle recession were observed, and 5 were suggestive of subluxation of the crystalline lens. Two cases were suspected for anterior segment intraocular foreign body on clinical examination, but UBM and computed tomography scanning together ruled out such a diagnosis.

CONCLUSIONS

Our study showed the value of UBM in the assessment of severely contused eyes and hyphema. It made possible evaluation for dialyses and recessions at presentation. Ultrasound biomicroscopy illustrated diverse subclinical disruptions in clinically invisible anterior segment structures.

Non-contact in vivo confocal scanning laser microscopy in exfoliation syndrome, exfoliation syndrome suspect and normal eyes

PURPOSE

This study aimed to evaluate the efficacy of non-contact confocal laser microscopy in detecting structural alterations of the cornea, iris and lens in fellow eyes of patients with clinically unilateral exfoliation syndrome (XFS) and XFS suspects.

METHODS

In a prospective observational case series, eyes of 12 patients with clinically unilateral XFS, six XFS suspects and six age-matched controls were divided into four groups. Group A included eyes with clinically visible exfoliation material (XFM) on the pupillary border or anterior lens capsule (n = 12); group B included fellow eyes of clinically unilateral XFS patients without visible XFM (n = 12); group C comprised eyes in XFS suspects with signs of pigment dispersion without visible XFM (n = 10), and group D consisted of control eyes with no evidence of XFM or pigment dispersion (n = 12). The cornea, iris and lens were imaged using a non-contact lens prototype for the Rostock Cornea Module (HRT II). Images were analysed by two observers masked to the clinical findings.

RESULTS

Visible XFM (group A) on the lens capsule was characterized by hyperreflectivity in the granular and central disc areas and hyporeflective spaces in the intermediate zones. Similar hyperreflectivity was noted in four of 12 and one of 10 eyes in groups B and C, respectively, but in none in group D. Corneal endothelial hyperreflective deposits were found in eight of 12, four of 12 and one of 10 eyes in groups A, B and C, respectively, and no eyes in group D.

CONCLUSIONS

This technology permits visualization of XFM and ⁄ or XFMrelated changes in the cornea and lens in the unaffected eyes of patients with clinically unilateral XFS. It may allow early detection of XFS and impact glaucoma screening and clinical surveillance decisions.

Angle imaging: advances and challenges

Primary angle closure glaucoma (PACG) is a major form of glaucoma in large populous countries in East and South Asia. The high visual morbidity from PACG is related to the destructive nature of the asymptomatic form of the disease. Early detection of anatomically narrow angles is important and the subsequent prevention of visual loss from PACG depends on an accurate assessment of the anterior chamber angle (ACA). This review paper discusses the advantages and limitations of newer ACA imaging technologies, namely ultrasound biomicroscopy, Scheimpflug photography, anterior segment optical coherence tomography and EyeCam, highlighting the current clinical evidence comparing these devices with each other and with clinical dynamic indentation gonioscopy, the current reference standard.