Clinical Course and Risk Factors for Visual Field Progression in Normal-Tension Glaucoma With Myopia Without Glaucoma Medications

Implications of myopia in diagnosis and screening of open angle glaucoma

PURPOSE OF REVIEW

Rapid increase in the prevalence of myopia has been documented worldwide. Myopia, especially high myopia, is not only an important risk factor for having open angle glaucoma (OAG), but also has a strong linking with the progression of OAG. Since myopic axial length (AXL) elongation is associated with nonglaucomatous optic nerve head (ONH) and visual field abnormalities, myopia poses a challenge in differential diagnosis of OAG. This review provides an overview of literature studying relationships between myopic AXL-elongation and diagnosis and prognosis of OAG, and functional and structural changes in the eye.

RECENT FINDINGS

Studies using optical coherence tomography (OCT), OCT-angiography, those using standard automated perimetry (SAP), other perimetric or electrophysiological methods showed dose-dependent effects of myopic AXL elongation on the structural changes in the ONH and parapapillary tissues, and functional abnormalities of an eye. Large cohort studies showed approximately one quarter of eyes with nonpathologic high myopia were complicated with various patterns of visual field defects including glaucoma-like ones.

SUMMARY

Findings of cross-sectional and longitudinal studies obtained using various fundus imaging devices must be integrated to perimetric results to improve differential diagnosis of OAG in myopic eyes, in which artificial intelligence technology may be useful.

Glaucoma Progression in Treatment-Naïve Patients With Normal Tension Glaucoma With Myopia-Role of Intraocular Pressure

PRCIS

While myopia has been recognized as a positive prognostic factor for normal tension glaucoma (NTG) progression in the adult population, some myopic NTG eyes exhibited significant progression within 2 years when left untreated, even under low intraocular pressure (IOP).

OBJECTIVE

To determine the natural history and risk factors associated with progressive retinal nerve fiber layer (RNFL) thinning in previously stable, treatment-naïve, patients with NTG with myopia.

METHODS

This study included 111 myopic NTG eyes without IOP-lowering treatment for at least 1 year and without disease progression during the treatment-free period. The RNFL thickness was measured, and a visual field test was performed every 6-12 months for >2 years. Patients with progressive changes were classified as the P(+) group, whereas those without progression were classified as the P(-) group. Cox proportional hazards model assessed risk factors of progression, whereas linear regression determined factors associated with the rate of RNFL thinning.

RESULTS

Progressive change was observed in 25 of the 111 participants [P(+) group, 22.5%]. A family history of glaucoma, higher mean IOP, and maximum IOP during the follow-up were significant factors both for being in the P(+) group and for a faster RNFL thinning. None with a mean IOP <11 mm Hg were in the P(+) group. Davies test identified that 14.2 mm Hg was a significant breakpoint ( P = 0.042), above which the rate of RNFL thinning increased significantly with the mean IOP ( R2 = 0.252, P = 0.034).

CONCLUSIONS

Patients with myopic NTG untreated for IOP, especially those with a family history of glaucoma or higher IOP, are at increased risk of progression. Early treatment initiation is advised for high-risk patients with myopic NTG, even when their condition appears stable.

How to diagnose glaucoma in myopic eyes by detecting structural changes?

Myopia is rapidly escalating globally, especially in East and Southeast Asia, where its prevalence among younger populations reaches alarming levels of 80-90 %. This surge contributes to a myopia epidemic linked to several ocular complications, including glaucoma. As myopic individuals age, the risk of developing glaucoma increases, and an additional concern arises from the growing frequency of refractive surgeries among younger individuals, making precise optic nerve assessments critical before surgery. Evaluating the optic nerve head (ONH) in myopic eyes is challenging, as structural changes due to myopia often resemble glaucomatous alterations. Techniques such as optical coherence tomography (OCT) have improved the examination of ONH microstructures, but interpreting results remains complex due to potential false-positive findings. Myopic eyes exhibit unique changes, such as peripapillary atrophy and altered neuroretinal rim configurations, making it crucial to distinguish these from true glaucomatous signs. Recent advancements in OCT technology and the establishment of myopia-specific normative databases have enhanced diagnostic accuracy. Parameters such as minimum rim width, ganglion cell-inner plexiform layer thickness and temporal raphe sign show promise in differentiating between glaucomatous and nonglaucomatous changes. Ultimately, a comprehensive approach incorporating multiple OCT metrics is essential for accurately diagnosing glaucoma in myopic patients. By integrating various structural evaluations and leveraging advanced imaging techniques, clinicians can better navigate the complexities of glaucoma diagnosis amidst the challenges posed by myopia. This review highlights the need for increased attention and tailored strategies in managing glaucoma risk within this increasingly affected population.

Effects of trabeculectomy on the postoperative central visual field as revealed by refraction values

PURPOSE

To evaluate the effects of trabeculectomy on the rate of deterioration of the central visual field (VF) in patients with normal-tension glaucoma (NTG), as revealed by refraction values.

STUDY DESIGN

Retrospective case series.

METHODS

We retrospectively analyzed 28 eyes, including 12 high myopic (spherical equivalent [SE] < - 6 diopters without pathological myopia) and 16 non-high myopic (SE ≥ - 6 diopters) eyes. The rate of VF deterioration (dB/year) was determined using linear regression analysis of 30 -2 and 10 -2 VF tests. The Wilcoxon signed-rank test was used to compare deterioration rates between groups. To assess the influence of initial post-surgery effects, statistical analyses were conducted with and without data from the initial postoperative VF exam.

RESULTS

Trabeculectomy significantly reduced intraocular pressure (IOP) in myopic (14.1 to 9.0 mmHg, P ≤ 0.01) and non-myopic (13.4 to 9.5 mmHg, P ≤ 0.01) eyes. Postoperatively, the 10-2 VF deterioration rate significantly decreased in myopic (- 1.31 to - 0.55 dB/year, P = 0.01) and non-myopic (- 0.80 to - 0.30 dB/year, P = 0.03) eyes. Excluding the first postoperative VF exam, the deterioration rates were - 0.51 ± 0.24 dB/year and - 0.54 ± 0.89 dB/year, respectively, indicating a minor impact on progression assessment.

CONCLUSIONS

Trabeculectomy may mitigate central VF deterioration in myopic NTG patients, emphasizing the potential benefits of timely surgical intervention. Further studies are needed to determine the optimal timing for surgery.

Assessing Glaucoma Severity and Progression in Individuals with Asymmetric Axial Length: An Intrapatient Comparative Study

PURPOSE

To investigate whether a difference exists in intereye glaucoma severity and progression in patients with asymmetric axial length.

DESIGN

Long-term observational study.

PARTICIPANTS

Patients older than 20 years with a diagnosis of glaucoma at Seoul National University Hospital, Seoul, Korea, between 2010 and 2020.

METHODS

Patients with a diagnosis of glaucoma in both eyes with an axial length difference of more than 1.0 mm were included. Each individual's eyes were classified into longer eye and shorter eye, and the baseline and follow-up clinical data were analyzed using the paired T-test and McNemar test.

MAIN OUTCOME MEASURES

Differences in clinical characteristics in patients with asymmetric axial length.

RESULTS

A total of 190 eyes of 95 patients with glaucoma with asymmetric axial length were included in the study. The patients' mean age was 51.2 ± 12.3 years, and the mean follow-up period was 10.1 ± 3.9 years. No difference was found in baseline intraocular pressure (IOP) or central corneal thickness between longer eyes and shorter eyes. Among the baseline disc parameters, ovality index, β-zone and γ-zone parapapillary atrophy (PPA) area were larger (P < 0.001) in the longer eyes. In the baseline OCT data, the retinal nerve fiber layer (RNFL) thickness (P = 0.009) and ganglion cell-inner plexiform layer (GCIPL) thickness (P < 0.001) were thinner in the longer eyes. According to a baseline visual field (VF) test, the mean deviation and VF index (VFI) values were significantly lower (P < 0.001, P = 0.034) in the longer eyes. Based on an analysis of glaucoma progression, the rate of change of superior GCIPL (longer eyes, -0.65 μm/year; shorter eyes, -0.40 μm/year), mean deviation (longer eyes, -0.40 dB/year; shorter eyes, -0.21 dB/year), and VFI (longer eyes, -0.92%/year; shorter eyes, -0.46%/year) were larger (P = 0.006, P = 0.005, P < 0.001) in the longer eyes. Additionally, the greater the difference in IOP fluctuation, the greater the difference in the rate of change between mean deviation and VFI.

CONCLUSIONS

When an axial length difference of more than 1.0 mm was present, glaucoma tended to be more severe and to progress faster in the longer eyes.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Peripapillary Versus Macular Thinning to Detect Progression According to Initial Visual Field Loss Location in Normal-Tension Glaucoma

PURPOSE

To investigate the predictive capabilities of peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell-inner plexiform layer (mGCIPL) thinning to detect visual field (VF) progression in normal-tension glaucoma patients with an initial parafoveal scotoma (IPFS) or nasal step (INS).

DESIGN

Retrospective cohort study.

METHODS

A total of 185 early-stage glaucoma eyes, followed for 10 years, were retrospectively stratified into IPFS and INS groups. Progressive pRNFL and mGCIPL thinning were assessed using spectral-domain optical coherence tomography and VF progression using both event- or trend-based analysis. Kaplan-Meier survival analysis compared VF survival in each VF phenotype with or without progressive pRNFL and mGCIPL thinning. Cox proportional regression analysis identified VF progression factors.

RESULTS

VF progression was detected in 42 IPFS (n = 86) and 47 INS (n = 99) eyes. Among VF progressors, pRNFL thinning was significantly faster in INS group compared to IPFS group (P < .01), while mGCIPL thinning was similar (P = .16). At 5 years, eyes with progressive mGCIPL thinning showed significantly lower VF survival in both VF phenotypes (all P < .05). Progressive pRNFL thinning showed significantly lower VF survival only in INS eyes (P = .015). Cox multivariate regression revealed that mGCIPL thinning predicted subsequent VF progression in IPFS eyes, while mGCIPL and pRNFL thinning had significant associations with VF progression in INS eyes.

CONCLUSIONS

mGCIPL outperforms pRNFL at early follow-up in detecting VF progression in IPFS eyes but not INS eyes. Appropriate selection of structural parameters (mGCIPL vs. pRNFL) maximizes early VF progression detection according to initial VF defect location.

Longitudinal changes in optical coherence tomography angiography characteristics in normal-tension glaucoma with or without high myopia

PURPOSE

To evaluate the structural, microvascular, and functional progression of normal tension glaucoma (NTG) with or without high myopia by examining longitudinal changes in optical coherence tomography angiography (OCTA) and visual field (VF) parameters.

METHODS

We evaluated 61 NTG eyes and classified 25 of the eyes with axial lengths (ALs) of ≥26 mm as highly myopic. We assessed the rate of change in OCTA parameters, namely radial peripapillary capillary (RPC) vessel density (VD), parafovea VD, deep parafovea VD, retinal nerve fibre layer (RNFL) thickness, and ganglion cell complex thickness. We evaluated the correlation of the rate of change in OCTA parameters with VF loss and AL.

RESULTS

Among the 61 NTG eyes, rates of loss of RPC VD, parafovea VD, deep parafovea VD, and RNFL thickness were significantly different from zero despite the nonsignificant rate of change in VF mean deviation (MD). Changes in these OCTA parameters did not differ significantly in highly myopic NTG eyes. The rate of change in VF MD was significantly correlated with the rate of change in parafovea VD in highly myopic and non-highly myopic NTG eyes. In highly myopic NTG eyes, AL was negatively correlated with the rates of loss of RNFL thickness, VF MD, and VF PSD.

CONCLUSION

NTG eyes with a relatively stable VF exhibited loss of VD and RNFL thickness. VF progression in NTG was correlated with decreasing parafovea VD, indicating a structure-function correlation. Greater AL may indicate faster VF loss and RNFL thinning in highly myopic NTG eyes.

Natural History and Risk Factors for Glaucoma Progression in Chinese Patients With Normal-Tension Glaucoma

Purpose

To characterize the natural history of normal-tension glaucoma (NTG) in Chinese patients.

Methods

The prospective observational cohort study included patients with untreated NTG with a minimum follow-up of 2 years. Functional progression was defined by visual field (VF) deterioration, while structural progression was characterized by thinning of the retinal nerve fiber layer (RNFL) or ganglion cell inner plexiform layer (GCIPL).

Results

Among 84 participants (mean age, 60.5 years; mean deviation, -5.01 decibels [dB]) with newly diagnosed NTG followed for an average of 69.7 months, 63.1% progressed during the observation period. Specifically, 29.8% progressed by VF, and 48.8% progressed by either RNFL or GCIPL. In Cox proportional hazards analysis, disc hemorrhage (hazard ratio [HR], 2.82; 95% confidence interval [CI], 1.48-5.35), female gender (HR, 1.98; 95% CI, 1.08-3.62), and mean IOP during the follow-up period (HR, 1.14 per mm Hg; 95% CI, 1.00-1.31) were significant predictors of glaucomatous progression. Additionally, longer axial length (AL; HR, 0.57 per millimeter; 95% CI, 0.35-0.94) was protective against VF progression faster than -0.50 dB/y, and higher minimum diastolic blood pressure (DBP; HR, 0.96 per mm Hg; 95% CI, 0.92-1.00) was protective against structural progression.

Conclusions

Nearly two-thirds of untreated Chinese patients with NTG progressed over an average follow-up of 70 months by VF, RNFL, or GCIPL. Disc hemorrhage, female gender, higher mean IOP, shorter AL, and lower minimum DBP were significant predictors for disease progression.

Optic neuropathy in high myopia: Glaucoma or high myopia or both?

Due to the increasing prevalence of high myopia around the world, structural and functional damages to the optic nerve in high myopia has recently attracted much attention. Evidence has shown that high myopia is related to the development of glaucomatous or glaucoma-like optic neuropathy, and that both have many common features. These similarities often pose a diagnostic challenge that will affect the future management of glaucoma suspects in high myopia. In this review, we summarize similarities and differences in optic neuropathy arising from non-pathologic high myopia and glaucoma by considering their respective structural and functional characteristics on fundus photography, optical coherence tomography scanning, and visual field tests. These features may also help to distinguish the underlying mechanisms of the optic neuropathies and to determine management strategies for patients with high myopia and glaucoma.

Different glaucoma progression rates by age groups in young myopic glaucoma patients

We aimed to investigate the age-related glaucoma progression rates in myopic normal tension glaucoma (NTG). In this long-term retrospective cohort (7.2 ± 3.5 years), we grouped patients based on their age at initial presentation: group A (age < 30 years, 60 eyes), group B (30 ≤ age < 40, 66 eyes), and group C (40 ≤ age < 50 years, 63 eyes). We used a linear mixed-effects model to estimate retinal nerve fiber layer (RNFL) defect width enlargement rates. Group A showed a significantly faster rate of RNFL defect progression (3.01 ± 1.74°/year) than those of groups B and C (2.05 ± 1.55°/year and 2.06 ± 1.29°/year, P = 0.004 and 0.002). The difference was more marked when calculated for the first 10 years of follow-up in group A, B, and C (3.95 ± 2.70°/year, 2.39 ± 1.64°/year, and 1.98 ± 1.31°/year), and between the periods of age < 30 years, 30 ≤ age < 40 years, and 40 ≤ age < 50 years within group A. This is the first evidence of rapid glaucoma progression in the young adulthood and stabilization in older age in myopic NTG. Clinicians should consider the potentially aggressive course of glaucoma, especially in younger patients with myopic NTG, in contrast to the general slow progression in adulthood.

Association of Bergmeister Papilla and Deep Optic Nerve Head Structures With Prelaminar Schisis of Normal and Glaucomatous Eyes

PURPOSE

To investigate factors associated with the severity of prelaminar schisis (PLS) in heathy subjects and glaucoma patients.

DESIGN

Prospective cross-sectional study.

METHODS

A total of 217 eyes of 217 subjects (110 normal eyes and 107 open angle glaucoma eyes) were studied. Frequency and severity of PLS were compared between normal and glaucomatous eyes. Multivariate logistic models were used to assess factors associated with the severity of PLS. Factors considered were age, axial length, glaucomatous damage indices, Bruch membrane opening (BMO) and anterior scleral canal opening parameters, tractional forces (posterior vitreous staging and presence of Bergmeister papilla), circumpapillary choroidal thickness, lamina cribrosa (LC) parameters, and peripapillary scleral (PPS) angle.

RESULTS

The frequency of PLS was 70.9% in normal eyes and 72.0% in glaucomatous eyes. There was no difference in frequency and severity between the groups. The presence of Bergmeister papilla was the strongest predictor of a more severe PLS in both normal and glaucomatous eyes (odds ratio [OR] + 9.78, 12.5; both P < .001). A larger PPS angle in normal eyes (OR = 1.19; P = .003) and a larger BMO area and a deeper LC depth in glaucomatous eyes (OR = 1.08, 1.05; both P = .038) were associated with severity of PLS.

CONCLUSIONS

The severity of PLS was strongly associated with the presence of Bergmeister papilla, suggesting a traction-related phenomenon. Correlation of PLS severity with larger BMO area and deeper LC depth, which are optic nerve head structures associated with glaucoma, suggested its possible relationship with glaucomatous damage.

Papillomacular bundle defect (PMBD) in glaucoma patients with high myopia: frequency and risk factors

Little is known about the papillomacular bundle defect (PMBD) in glaucoma. As such, we investigated the frequency of PMBD in glaucoma patients with high myopia, and its risk factors. In this retrospective, cross-sectional study, retinal nerve fiber layer (RNFL) defect was analyzed in 92 glaucomatous eyes with high myopia (axial length of 26.0 mm or more or an average spherical value of - 6.0 diopters or less). After dividing them into two groups with and without PMBD, the clinical characteristics of the groups were compared and analyzed. The mean age of the patients was 52.1 ± 10.5 years, and there were 53 males and 39 females. PMBD were observed in 55 eyes (59.8%). There was no significant intergroup difference in baseline or follow-up intraocular pressure (IOP). Parapapillary atrophy (PPA)-to-disc-area ratio (OR 3.83, CI: 1.58-10.27, p = 0.010), lamina cribrosa defect (LCD; OR 2.92, CI: 1.14-8.13, p = 0.031) and central visual field defect (CVFD; OR 3.56, CI: 1.38-9.58, p = 0.010) were significantly associated with the PMBD..

Deep Optic Nerve Head Morphology in Tilted Disc Syndrome and Its Clinical Implication on Visual Damage

Purpose

To study deep optic nerve head (ONH) morphology in tilted disc syndrome (TDS) and identify factors associated with retinal nerve fiber layer (RNFL) defect.

Methods

In patients with TDS, we evaluated the optic disc shape using the Bruch's membrane opening (BMO)-anterior scleral canal opening (ASCO) offset and measured the border tissue (BT) length, depth, and angle in the direction of the tilt, using radial ONH optical coherence tomography (OCT). We compared the parameters between the TDS groups with and without RNFL defects.

Results

Twenty-one eyes had no glaucomatous RNFL defect, and 38 eyes had a glaucomatous RNFL defect. The group with RNFL defects had a higher baseline IOP, larger tilt axis of BMO-ASCO optic disc margin (76.4° ± 14.5° vs. 87.9° ± 15.4°, P = 0.012), larger BMO-lamina cribrosa insertion (LCI) angle (25.6° ± 9.3° vs. 43.6° ± 15.2°, P < 0.001), and more lamina cribrosa (LC) defects (4.3% vs. 30.6%, P = 0.028) than without RNFL defects. The tilt axis and BMO-LCI angle were significant factors after adjusting for baseline IOP and LC defect. The BMO-LCI angle had excellent diagnostic power for glaucomatous RNFL defect in TDS, similar to the visual field mean deviation.

Conclusions

OCT-based large deep ONH BT angle and tilt axis were factors associated with the presence of RNFL defects in TDS. The results suggest a mechanism of RNFL defect associated with structural ONH deformation. Further investigations are warranted to understand the role of ONH structures in a general population with and without optic disc tilt.

Deep Optic Nerve Head Structures Associated With Increasing Axial Length in Healthy Myopic Eyes of Moderate Axial Length

PURPOSE

To elucidate which swept-source optical coherence tomography (OCT)-derived optic nerve head (ONH) parameters are associated with longer axial length (AXL) in healthy myopic eyes.

DESIGN

Prospective cross-sectional observational study.

METHODS

Two hundred eleven healthy eyes of 140 participants (96 emmetropic-mild myopic [AXL: 22.2-24.5 mm], 83 moderately myopic [24.5-26.0 mm], and 32 highly myopic [26.0-27.4 mm] eyes) were enrolled. Bruch membrane opening (BMO), anterior scleral canal opening (ASCO) area and ovality, minimum rim width, parameters defining misalignment between the BMO and ASCO planes, OCT-defined region of perineural canal retinal epithelium atrophy and externally oblique choroidal border tissue, circumpapillary retinal nerve fiber layer thickness (cpRNFLT), circumpapillary choroidal thickness (cpChT), lamina cribrosa parameters, and peripapillary scleral (PPS) angle were calculated from BMO-centered radial scans reconstructed from 3D raster scans. Multivariate linear mixed models were used to elucidate ONH parameters that are independently associated with AXL.

RESULTS

Longer AXL was associated with a greater misalignment between ASCO and BMO planes, larger region of externally oblique choroidal border tissue, thinner cpChT, larger PPS angle, larger ASCO area, and thicker cpRNFLT (all P < .040 after Bonferroni's correction for number of included explanatory variables).

CONCLUSIONS

A greater misalignment between BMO and ASCO planes, thinner choroid, a more posteriorly bowed PPS, an enlargement of ASCO, and thicker cpRNFLT were each associated with longer AXL. An enhanced understanding of these AXL-associated configurations should provide essential information to improve our ability to detect glaucoma-induced ONH morphology in myopic eyes.

Myopic tilted disc: Mechanism, clinical significance, and public health implication

Myopic tilted disc is a common structural change of myopic eyes. With advancing ocular imaging technology, the associated structural changes of the eye, particularly the optic nerve head, have been extensively studied. These structural changes may increase patients' susceptibility to axonal damage and the risk of developing serious optic neuropathies including glaucoma. They also lead to diagnostic difficulties of disease suspects and treatment dilemmas of patients, which implicate clinical practice and subsequently the health care system. In the context of the mounting prevalence of myopia worldwide and its implications to irreversible visual impairment and blindness, it is essential to gain a thorough understanding of the structural changes of myopia. Myopic tilted disc has been extensively investigated by different study groups. However, generalizing the knowledge could be difficult because of the variable definitions of myopic tilted disc utilized in these studies and the complexities of the changes. The current review aimed to clarify the concepts and discuss various aspects of myopic tilted disc, including the definitions, association with other myopia-related changes, mechanism of tilted disc development, structural and functional changes, and clinical implications.

The natural history of untreated ocular hypertension and glaucoma

Glaucoma is a chronic, progressive disease leading to irreversible blindness if left untreated; however, since reducing intraocular pressure has proven to be successful in slowing disease progression, little is known about the natural history of untreated glaucoma. This knowledge can be valuable in guiding management decisions in the era of personalized medicine. A systematic search was performed in Medline (PubMed), Embase, and Web of Science in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRIMSA) guidelines. The rate of structural and/or functional progression and conversion to glaucoma or to a more advanced stage of glaucoma are discussed for ocular hypertension and different types of open-angle glaucoma. Forty-three studies were included. Different rates of progression were found both among and within the different diagnostic groups that belong to the open-angle glaucoma spectrum. The highest rate was found in pseudoexfoliation glaucoma, followed by high tension glaucoma, normal tension glaucoma, and ocular hypertension, in decreasing order. The lowest rate was observed in glaucoma suspects. The known rates of progression provide valuable prognostic information for ophthalmologists and patients. Nonetheless, due to high variability among patients, individual progression cannot be accurately predicted and repeated follow-up examinations are required to estimate individual progression.

Finite element modeling of effects of tissue property variation on human optic nerve tethering during adduction

Tractional tethering by the optic nerve (ON) on the eye as it rotates towards the midline in adduction is a significant ocular mechanical load and has been suggested as a cause of ON damage induced by repetitive eye movements. We designed an ocular finite element model (FEM) simulating 6° incremental adduction beyond the initial configuration of 26° adduction that is the observed threshold for ON tethering. This FEM permitted sensitivity analysis of ON tethering using observed material property variations in measured hyperelasticity of the anterior, equatorial, posterior, and peripapillary sclera; and the ON and its sheath. The FEM predicted that adduction beyond the initiation of ON tethering concentrates stress and strain on the temporal side of the optic disc and peripapillary sclera, the ON sheath junction with the sclera, and retrolaminar ON neural tissue. However, some unfavorable combinations of tissue properties within the published ranges imposed higher stresses in these regions. With the least favorable combinations of tissue properties, adduction tethering was predicted to stress the ON junction and peripapillary sclera more than extreme conditions of intraocular and intracranial pressure. These simulations support the concept that ON tethering in adduction could induce mechanical stresses that might contribute to ON damage.

Features and changes in retinal nerve fiber layer thickness in high myopic ocular hypertension: a 1-year prospective follow-up

PURPOSE

To observe the features and changes in peripapillary retinal nerve fiber layer (pRNFL) thickness in highly myopic ocular hypertension (HM-OHT) patients.

STUDY DESIGN

Prospective observation study.

METHODS

Individuals who met the inclusion criteria were recruited into three groups: the healthy high myopia (HM), non-highly myopic ocular hypertension (OHT) and HM-OHT group. The spherical equivalent refraction, axial length, intraocular pressure, central corneal thickness and pRNFL thickness were collected and compared between groups. The OHT and HM-OHT group were followed up for 12 months. The changes in pRNFL thickness across the follow-up times were analyzed.

RESULTS

The study included 92 subjects. The mean pRNFL thicknesses were 102.5 ± 11.1 μm in the HM (31 people), 101.9 ± 11.7 μm in the OHT (34 people) and 102.2 ± 12.0 μm in the HM-OHT group (27 people). There was no statistical difference in the mean pRNFL thickness among the three groups. The HM-HOT group and HM group had thicker temporal sectoral (p < 0.05) pRNFL thickness and thinner superior sectoral (p = 0.015) pRNFL thickness than the OHT group. During the 12-month follow-up, the mean pRNFL thickness of the HM OHT group decreased, with an annual reduction of -0.93 ± 0.14 μm. There was a significant difference across the three visits (p < 0.05), while there were no significant differences in the OHT group (p = 0.591).

CONCLUSIONS

After ocular magnification correction, the HM-OHT group did not have thinner pRNFL thickness than the other two groups. However, the thickness decreased significantly over time.

Association of progressive optic disc tilt with development of retinal nerve fibre layer defect in children with large cup-to-disc ratio

BACKGROUND/AIMS

Whereas myopic optic disc deformation has been posited as a risk factor for glaucomatous damage, longitudinal studies evaluating their association have been sparse. We investigated whether the optic nerve head (ONH)'s morphological alteration during myopia progression play any role in development of retinal nerve fibre layer defect (RNFLD) in children with a large vertical cup-to-disc ratio (vCDR).

METHODS

Sixty-five normotensive eyes of 65 children aged under 8 years with (1) vCDR ≥0.5 but no additional signs of glaucoma and (2) who could be tracked at young adulthood (18-28 years) were included. Children's spherical equivalent (SE), intraocular pressure, vCDR and optic disc tilt ratio were recorded. Rare events logistic regression analysis was employed to identify factors associated with RNFLD-development risk.

RESULTS

The study group's mean age was 5.4±1.3 years, its average vCDR was 0.62±0.07, and the average SE was -0.3±1.4 dioptres ((D), range -3.15 to 2.75D) at the baseline. After an average follow-up of 16.1±3.0 years, the mean vCDR was 0.64±0.09, and the mean SE, -3.2±2.2D (range -7.25 to 0.00 D). Among the 65 eyes, 12 (18.5%) developed RNFLD. A greater SE change (OR=1.737, p=0.016) and a greater increase in tilt ratio (OR=2.364, p=0.002) were both significantly associated with higher RNFLD-development risk.

CONCLUSION

In this cohort of Korean children with large vCDR, progressive optic disc tilt in the course of myopia progression was associated with higher RNFLD-development risk. This finding suggests that morphological alterations in the ONH during axial elongation might represent an underlying susceptibility to glaucomatous damage in large-vCDR children.

Association of Optic Disc Tilt and Torsion with Open-Angle Glaucoma Progression Risk: Meta-Analysis and Meta-Regression Analysis

PURPOSE

To evaluate the association of optic disc deformation with open-angle glaucoma (OAG) progression risk.

DESIGN

Meta-analysis and meta-regression analysis.

METHODS

Reports on the association of optic disc tilt and/or torsion with OAG progression published to June 2020 were identified in the PubMed, EMBASE, and Cochrane databases. Tilt ratio was measured as the longest-to-shortest diameter ratio of the optic disc. The angle (in degrees) between the vertical meridian and the disc's long axis was defined as the torsional angle. We used random-effects models to combine the pooled effects. Random-effects meta-regression was used to quantify the study characteristics' potential moderating influences. The protocol was registered in the PROSPERO International Database (CRD42020201151).

RESULTS

Eleven longitudinal studies (1100 participants) were included. For 10 of them evaluated for tilt ratio and glaucoma progression, the pooled hazard ratio (HR) was 0.988 (95% confidence interval [CI] 0.921-1.059; I² = 59%) per 0.1-unit increase. In the meta-regression-based subgroup analysis, risk tended to decrease as the patients' mean age increased (P = .08). For 7 of the studies (605 patients) reporting data on torsion and glaucoma progression, the pooled HR was 0.936 (95% CI 0.860-1.018; I² = 32%) per 10-degree increase. The meta-regression analyses showed that the glaucoma progression assessment methods had a modulating influence (P = .01). In studies assessing just functional glaucomatous progression, the pooled HR was 0.890 (95% CI 0.831-0.952; I² = 0%).

CONCLUSION

Evidence for the effects of optic nerve deformation on glaucoma progression is still lacking. Future research using stratified analysis according to age and tailored diagnostic criteria will allow for more rigorous analyses for this topic.

Rates of Retinal Nerve Fiber Layer Thinning in Distinct Glaucomatous Optic Disc Phenotypes in Early Glaucoma

PURPOSE

To compare spectral-domain optical coherence tomography (SDOCT) measured circumpapillary retinal nerve fiber layer (cpRNFL) among 4 glaucomatous optic disc phenotypes in early glaucoma.

DESIGN

Clinical cohort study METHODS: In this study, 218 early glaucoma eyes that had at least 3 years of follow-up and a minimum of 4 SDOCT scans were recruited. The optic discs were classified into 4 types based on appearance: 76 generalized cup enlargement (GE), 53 focal ischemic (FI), 22 myopic glaucomatous (MY), and 67 senile sclerotic (SS). A linear mixed effects model was used to compare the rates of global and regional cpRNFL thinning among optic disc phenotypes.

RESULTS

After adjusting for confounders, the SS group (mean [95% CI]: -1.01 [-1.30, -0.73] µm/y) had the fastest mean rate of global cpRNFL thinning followed by FI (-0.77 [-0.97, -0.57] µm/y), MY (0.59 [-0.81, -0.36] µm/y), and GE (-0.58 [-0.75, -0.40] µm/y) at P < .001. The inferior temporal sector had the fastest rate of cpRNFL thinning among the regional measurements except for the MY group (-0.68 [-1.10, -0.26] µm/y, P = .002). In the multivariable analysis, GE (P = .002) and MY (P = .010) phenotypes were associated with significantly slower global rates of cpRNFL thinning compared with the SS phenotype.

CONCLUSIONS

Rates of cpRNFL thinning were different among the 4 glaucomatous optic disc phenotypes. Those patients with early glaucoma with SS phenotype have the fastest cpRNFL thinning. These patients may benefit from more frequent monitoring and the need to advance therapy if cpRNFL thinning is detected.

Long-Term Effectiveness and Safety of Tafluprost, Travoprost, and Latanoprost in Korean Patients with Primary Open-Angle Glaucoma or Normal-Tension Glaucoma: A Multicenter Retrospective Cohort Study (LOTUS Study)

This multicenter retrospective cohort study compared the effectiveness and safety of long-term tafluprost, travoprost, or latanoprost in patients with primary open-angle glaucoma (POAG) or normal-tension glaucoma (NTG). Data were extracted from electronic medical records of 300 patients treated with tafluprost, travoprost, or latanoprost for >6 months. Propensity matching for age and sex was used for effectiveness and safety comparisons. The primary endpoint was visual field (VF) progression via mean deviation (MD) slope. Secondary endpoints were change of MD, intraocular pressure, pattern standard deviation, VF index, and advanced glaucoma intervention study score. Treatment-related adverse events (AEs) were also compared between groups. Overall, 216 POAG or NTG patients were matched into Match Set 1 (72 patients/group), and 177 NTG-only patients in Match Set 2 (59 patients/group) according to: age (mean: 61, 62 years) and sex (male: 53, 56%). There were no statistically significant between-group differences regarding MD slope (p = 0.413, p = 0.374 in Match Sets 1 and 2, respectively). There were no significant between-group differences/tendencies regarding secondary endpoints. No AEs were serious, and there were no significant between-group differences regarding reported AEs. In patients with POAG or NTG, long-term tafluprost, travoprost, or latanoprost showed similar effects. All three prostaglandin analogs had good long-term safety profiles.

Characteristics of progressive temporal visual field defects in patients with myopia

Temporal visual field damage (VFD) is the common type of non-glaucomatous VF defects found in eyes with myopia. However, little is known about the factors associated with its progression. We investigated the characteristic of myopic eyes with progressive temporal VF defects. This retrospective, observational study included a total of 116 eyes: 39 eyes with temporal VFDs and an axial length greater than 24.5 mm, 77 eyes with typical glaucomatous VFDs who were followed up more than 5 years. VF progression was evaluated with Trend-based global progression analysis. In the temporal VFD group, the greater tilt ratios, the higher prevalence of β-zone peripapillary atrophy (β-PPA), the substantial increase in β-PPA were found, compared to the typical glaucomatous VFD groups (all P-values ≤ 0.001). The temporal VFD group had the slower progression than the typical glaucomatous VFD group on trend-based GPA (P = 0.047). In the multivariate linear regression analysis, the change of β-PPA area over years was related to temporal VFD progression (B, − 0.000088, P = 0.003). In conclusion, myopic eyes with the temporal VFD, which come with growing β-PPA area, should be monitored with extra caution.

Glaucoma conversion of the contralateral eye in unilateral normal-tension glaucoma patients: a 5-year follow-up study

BACKGROUND/AIMS

To investigate clinical characteristics and risk factors for glaucoma conversion of the contralateral eye in unilateral normal-tension glaucoma (NTG) patients.

METHODS

A retrospective observational cohort study was conducted on a total of 76 subjects who had been diagnosed with unilateral NTG at the baseline and followed up for more than 5 years. Glaucoma conversion in the contralateral eye was defined as increased thinning of neuro-retinal rim, development of retinal nerve fibre layer defect and/or development of glaucomatous visual field defect.

RESULTS

During the mean follow-up period of 7.3±2.4 years, 21 of 76 (27.6%) subjects were confirmed to have developed glaucoma in the non-glaucomatous contralateral eye. The 5-year rate of glaucoma conversion in contralateral eyes was 19.7%. The maximum width of β-zone parapapillary atrophy (MWβPPA)-disc diameter (DD) ratio at the baseline and the presence rate of disc haemorrhage during follow-up period were significantly greater in the contralateral eyes of the conversion group than in those of the non-conversion group (p=0.011, <0.001, respectively). A multivariate Cox-proportional hazard model revealed intraocular pressure (IOP) over 17 mm Hg (HR 5.05, p=0.031), central corneal thickness (CCT) under 491 μm (HR 4.25, p=0.025) and MWβPPA-DD ratio over 0.32 (HR 6.25, p=0.003) in contralateral eye at the baseline as the independent risk factors for glaucoma conversion.

CONCLUSIONS

Among unilateral NTG patients, those with low CCT and high MWβPPA-DD ratio as well as high IOP in the contralateral eye are more likely to develop glaucoma in that eye during long-term follow-up.

Pre-perimetric Open Angle Glaucoma with Young Age of Onset: Natural Clinical Course and Risk Factors for Progression

PURPOSE

To investigate the natural clinical course of more than 5 years and the risk factors of progression in patients with pre-perimetric open angle glaucoma (OAG) of "young age of onset (under age 40)" without treatment.

DESIGN

Retrospective observational case series.

METHODS

Optic disc photography, red-free retinal nerve fiber layer (RNFL) photography, optical coherence tomography, and visual field (VF) examinations were performed every 6 months. Glaucoma progression was defined as structural or functional deterioration. A linear mixed-effects model was used to estimate the rate of structural and functional changes. Kaplan-Meier survival analysis and log-rank testing were used to compare survival experiences, and Cox proportional hazards modeling was performed to identify risk factors for glaucoma progression.

RESULTS

Of the 98 eyes of 98 patients (mean age, 30.6 years old), glaucoma progression was detected in 42 eyes (42.9%). The rate of average RNFL thickness thinning was -0.46 ± 0.50 μm/y, and the mean deviation (MD) change was -0.03 ± 0.13 dB/y. The glaucoma progression probability at 5 years was 39% by structural criteria and 5% by functional criteria. Older age at diagnosis (P = .004), presence of temporal raphe sign (horizontal straight line on macular ganglion cell-inner plexiform layer thickness map) (P = .011), lamina pore visibility (P = .034), and greater pattern standard deviation (P = .005) were significant factors for glaucoma progression.

CONCLUSIONS

In untreated pre-perimetric OAG patients with a "young age of onset" condition, the estimated MD slope for the disease course of more than 5 years was -0.03 dB/y, and the average RNFL thinning rate was -0.46 μm/y. The predictors for progression were structural parameters of temporal raphe sign, lamina pore visibility, and functional parameter of pattern standard deviation.

The Dynamic Scleral Extracellular Matrix Alterations in Chronic Ocular Hypertension Model of Rats

Intraocular pressure (IOP) generates stress and strains in the laminar cribrosa and sclera, which may affect the development and progression of glaucoma. Scleral stiffness and material components have changed under elevated IOP. However, the detailed changes of the components of the hypertensive sclera are not well understood. In this study, we aimed to investigate the changes of the main components in the scleral extracellular matrix (ECM), and matrix metalloproteinase 2 (MMP2) and their relationship with time under chronic elevated IOP in Sprague–Dawley rats. An ocular hypertension model was established in the right eyes by anterior chamber injection with 0.3% carbomer solution. The left eye was used as the contralateral control. Immunofluorescent imaging of the tissue frozen sections, Western blot analysis, and quantitative PCR (qPCR) were performed to detect the expressions of type I collagen (COL1), elastin, and MMP2 in the sclera. The ocular hypertension model was successfully established. As compared to the left eyes, the immunofluorescence imaging, Western blot analysis, and qPCR showed that COL1, elastin, and MMP2 were significantly increased in the right eyes at 1 week (all P < 0.05). At 2 weeks, COL1 in the right eyes tended to be lower than that in the left eyes, while elastin and MMP2 were still higher (all P < 0.05) in the right eyes. When the IOP was elevated for 4 weeks, both COL1 and MMP2 were lower than those in the left eyes (all P < 0.05), while elastin between the two eyes was similar (P > 0.05). Under this 4-week hypertensive state, COL1 and elastin were initially elevated at 1 week, and then obviously reduced from 2 to 4 weeks. Consistently, MMP2 was gradually increased, with a peak at 2 weeks, and then decreased at 4 weeks. In conclusion, the chronic elevated IOP induced dynamic scleral ECM alterations in rats in a pressure- and time-dependent manner. MMP2 may play an important role in the balance between ECM synthesis and degradation and could potentially be a novel target for glaucoma intervention.

Hemisphere opposite to vascular trunk deviation is earlier affected by glaucomatous damage in myopic high-tension glaucoma

PURPOSE

To investigate whether the position of the central vascular trunk, as a surrogate of lamina cribrosa (LC) shift, is associated with the initial hemisphere of visual field defect in myopic high-tension glaucoma (HTG) eyes.

METHODS

The deviation of the central vascular trunk was measured from the center of the Bruch's membrane opening (BMO), which was delineated by OCT imaging. The angular deviation was measured with the horizontal nasal midline as 0° and the superior location as a positive value. The initial hemisphere developing visual field defect was defined as three connected abnormal points (having a P value with less than 0.5% probability of being normal) appearing in only one hemisphere in pattern deviation plots. If those points were observed in both hemispheres initially, the eye was classified as bi-hemispheric visual field defect.

RESULTS

Initially, 36 eyes (44%) had superior visual field defects, 27 (33%) inferior visual field defects, and 18 (22%) bi-hemispheric visual field defects. After a mean follow-up of 5 years, the number of bi-hemispheric visual field defects had increased to 34 (42%). A logistic regression analysis revealed that inferior deviation of vascular trunk was the only factor associated with initial inferior visual field defect (P = 0.001), while initial bi-hemispheric visual field defects were associated with worse mean deviation at initial visits (P<0.001). A conditional inference tree analysis showed that both the angular deviation (P<0.001) and initial mean deviation (P = 0.025) determined the initial hemispheres developing visual field defect.

CONCLUSIONS

Although both hemispheres were involved as glaucoma progression, the axons on the side counter to the vascular trunk deviation were damaged earlier in HTG. This finding implies the LC shift could add additional stress to axons exposed to high intraocular pressure.

Bilaminar Structure of the Human Optic Nerve Sheath

PURPOSE/AIM

We aimed to characterize the connective tissue microanatomy, elastin abundance, and fiber orientation in the human optic nerve sheath, also known as the optic nerve dura mater, for correlation with its biomechanical properties.

MATERIALS AND METHODS

Seven whole human orbits aged 4-93 years, and five isolated human optic nerve sheaths aged 26-75 years were formalin fixed, paraffin embedded, coronally sectioned, stained by Masson trichrome and van Gieson's elastin methods, and analyzed quantitatively for elastin fiber abundance and orientation. Elastin area fraction was defined as area stained for elastin divided by total area.

RESULTS

While unilaminar in children, the adult ON sheath exhibited distinct inner and outer layers. Collagen was denser and more compact in the inner layer. Elastin area fraction was significantly greater at 6.0 ± 0.4% (standard error of mean) in the inner than outer layer at 3.6 ± 0.4% (P < 10^-5). Elastin fibers had three predominant orientations: longitudinal, diagonal, and circumferential. Of circumferential fibers, 63 ± 4.7% were in the inner and 37 ± 4.7% in the outer layer (P < 10^-4). Longitudinal and diagonal fibers were uniformly distributed in both layers. Elastin density and sheath thickness increased significantly with age (P < .01).

CONCLUSIONS

The adult human optic nerve sheath is bilaminar, with each layer containing elastin fibers oriented in multiple directions consistent with isotropic properties. Differences in laminar elastin density and orientation may reflect greater tensile loading in the inner than in the outer layer.