Myopic glaucomatous eyes with or without optic disc shape alteration: a longitudinal study

Evaluating glaucoma in myopic eyes: Challenges and opportunities

The increasing global prevalence of myopia presents a significant public health concern, and growing evidence has demonstrated that myopia is a major risk factor for the development of open-angle glaucoma. Therefore, timely detection and management of glaucoma in myopic patients are crucial; however, identifying the structural alterations of glaucoma in the optic nerve head (ONH) and retinal tissues of myopic eyes using standard diagnostic tools such as fundus photography, optical coherence tomography (OCT), and OCT angiography (OCTA) presents challenges. Additionally, myopia-related perimetric defects can be confounded with glaucoma-related defects. We comprehensively examine the challenges encountered in evaluating glaucoma in myopic eyes through various diagnostic tools, including fundus photography, OCT of the ONH, retinal nerve fiber layer, and macular ganglion cell layer, OCTA, and perimetry. We also explore potential opportunities to address these challenges, providing insights for clinicians to effectively manage myopic glaucoma patients in clinical practice.

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.

Implications of optic disc rotation in the visual field progression of myopic open-angle glaucoma

PURPOSE

To investigate the relationship between the characteristics of optic disc rotation and visual field (VF) progression in patients with myopic open-angle glaucoma (OAG).

METHODS

We included 53 eyes from 53 myopic OAG patients who were followed-up over a 3-year period. The characteristics of optic disc rotation including the degree of optic disc rotation, direction of optic disc rotation, and optic disc rotation-VF defect correspondence were investigated. The rates of global and regional VF progression were compared with different characteristics of optic disc rotation.

RESULTS

Thirty-seven eyes (69.8%) showed inferior optic disc rotation and 41 (77.4%) eyes showed optic disc rotation-VF defect correspondence. The inferiorly rotated optic discs with corresponding superior VF defect had faster VF progression in the superior peripheral region (P = 0.028) and superiorly rotated optic discs with corresponding inferior VF defect had faster VF progression in the inferior peripheral region (P = 0.031). The VF progression was restricted to the superior hemifield in the eyes with inferiorly rotated optic discs and corresponding superior VF defects.

CONCLUSION

In myopic OAG patients, the direction of optic disc rotation might predict faster VF progression in the corresponding peripheral region.

Measurement of the Tilt Angle of the Optic Disc Using Spectral-Domain Optical Coherence Tomography and Related Factors in Myopia

Purpose

This study presents a novel, three-dimensional method for measuring the tilt angle of the tilted optic disc (TOD) using spectral-domain optical coherence tomography (SD-OCT) and investigates the correlation between ocular-related parameters and TOD.

Methods

We included the right eyes of 243 healthy young individuals, categorized by axial length. We measured the ovality index (OI) and dihedral angle (DA) using SD-OCT infrared ray fundus photographs and high-resolution cross-sectional images of the optic disc, respectively. The relationships between OI, DA, and ocular-related parameters were analyzed.

Results

Eyes in the longer axial length group exhibited a lower OI and a higher DA, along with thinner nasal and inferonasal circumpapillary retinal nerve fiber layer (cpRNFL) and thicker temporal and superotemporal cpRNFL. There was a significant relationship between DA and cpRNFL thickness. The new method utilizing DA to measure the tilt angle of TOD demonstrated high repeatability.

Conclusions

We propose a novel, three-dimensional, and quantitative method for evaluating the tilt degree of TOD. A higher degree of myopia indicated a greater tilt angle of the TOD, and a greater TOD suggested additional changes in cpRNFL thickness. These findings should be considered when interpreting increased susceptibility and early assessment of glaucoma in myopia.

Translational Relevance

DA could serve as a superior indicator for describing TOD morphology during eyeball elongation and evaluating its impact on related parameters of the optic disc and peripapillary structures in the myopic population.

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.

Prevalence and Factors Associated with Optic Disc Tilt in the Primary Open-Angle African American Glaucoma Genetics Study

PURPOSE

To investigate the prevalence and factors associated with optic disc tilt in the eyes of Black Americans with glaucoma.

DESIGN

Cross-sectional.

PARTICIPANTS

Subjects with glaucoma participating in the Primary Open-Angle African American Glaucoma Genetics (POAAGG) study.

METHODS

Stereo pairs of optic disc images were assessed independently by POAAGG-certified nonphysician graders for quantitative features including maximum and minimum linear disc diameters, and qualitative features including gradeability of images, shape of the cup, rim plane position, β-peripapillary atrophy, sloping region adjacent to the outer disc margin, and rim pallor. Discrepancies were adjudicated by an ophthalmologist. Descriptive statistics and P values were generated for associations of tilt with demographic and ocular characteristics. Stepwise multivariable analysis was performed with logistic regression using Generalized Estimating Equations (GEEs) to account for inter-eye correlation within subjects.

MAIN OUTCOME MEASURES

Tilt Ovality Index (TOI) of >1.30 and Stereoscopically Identified optic disc Tilt (SIT).

RESULTS

Among 1251 subjects with data on both eyes, 104 (8.3%) had TOI. Subjects with TOI were less likely to be male (adjusted odds ratio [aOR], 0.46, 95% confidence interval [CI], 0.29-0.74, P < 0.001). Eyes with TOI were less likely to have large cup disc ratios (aOR, 0.18, 95% CI, 0.06-0.53, P < 0.001) and less likely to have cylinder-shaped cups compared with conical-shaped cups (aOR, 0.31, 95% CI, 0.19-0.49, P < 0.001). Among 1007 subjects with data on both eyes, 254 (25.2%) had SIT. Subjects with SIT were younger (aOR, 0.95, 95% CI, 0.93-0.96, P < 0.001), and eyes with SIT were more likely to have oval-shaped discs compared with round discs (aOR, 1.82, 95% CI, 1.32-2.52, P < 0.001), more likely to have a sloping region adjacent to the outer disc margin instead of being flat (aOR, 3.26, 95% CI, 2.32-4.59, P < 0.001), and less likely to have cylinder-shaped cups compared with conical-shaped cups (aOR, 0.59, 95% CI, 0.41-0.85, P < 0.001). Both TOI and SIT were not associated with myopia.

CONCLUSIONS

There are substantial numbers of tilted optic discs in glaucoma patients with African ancestry. They occur more frequently in female subjects and younger subjects and are associated with several ocular features but not with myopia.

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.

Progressive Optic Disc Tilt in Young Myopic Glaucomatous Eyes

Purpose

To explore the progressive change and associated factors of optic disc tilt in young myopic glaucomatous eyes by analyzing long-term follow-up data.

Methods

Optic disc images were obtained from spectral-domain optical coherence tomography enhanced depth imaging from at least five different visits. At each visit, the disc tilt angle (DTA), defined as the angle between the Bruch's membrane opening plane and the optic canal plane, was estimated at the central frame that passes through the optic disc. Glaucoma progression was assessed on the basis of changes noted on serial optic disc and retinal nerve fiber layer photographs or changes in the visual field (VF). A linear mixed effect model was used to assess the influence of parameters (age, sex, baseline and follow-up intraocular pressure, retinal nerve fiber layer thickness, VF mean deviation, axial length, central corneal thickness), and presence of glaucomatous progression upon DTA change.

Results

A total of 26 eyes of 26 young myopic primary open-angle glaucoma patients (axial length >24.0 mm; mean age, 25.1 ± 4.0 years; mean follow-up, 3.3 ± 0.9 years) were included. DTA was 7.0 ± 3.4 degrees at baseline and 8.3 ± 3.8 degrees at last visit, which represents a significant difference (p < 0.001). Worse VF mean deviation (p < 0.001) and longer axial length (p = 0.006) were significantly associated with DTA increase.

Conclusions

Young myopic glaucomatous eyes showed progressive optic disc tilting. Progressive optic disc tilting in young myopic glaucomatous eyes may be related to either continuous axial myopic shift or glaucomatous structural change.

Age-Related Physiologic Thinning Rate of the Retinal Nerve Fiber Layer in Different Levels of Myopia

Purpose

To investigate the effect of refractive error on the physiologic thinning rate of the retinal nerve fiber layer (RNFL) in healthy eyes. Materials and Methods. This study analyzed 223 eyes of 141 healthy subjects followed for more than 5 years and underwent at least five serial spectral domain optical coherence tomography (SD-OCT) examinations. Longitudinal RNFL measurements were analyzed by linear mixed models incorporating follow-up duration, baseline RNFL thickness, spherical equivalent (SE), age, intraocular pressure, and visual field mean deviation. Thinning rates were classified according to SE into three groups: nonmyopic (NM; >0 D), mild-to-moderately myopic (MM; >–6 D and ≤0 D), and highly myopic (HM; ≤–6 D).

Results

The overall slopes of change in RNFL thickness over time in the NM, MM, and HM groups were −0.305 ± 0.128, −0.294 ± 0.068, and −0.208 ± 0.097 μm/yr, respectively. Slopes of RNFL thickness changes in these groups were −0.514 ± 0.248, −0.520 ± 0.133, and −0.528 ± 0.188 μm/yr, respectively. Slopes of RNFL thickness changes in these groups were −0.514 ± 0.248, −0.520 ± 0.133, and −0.528 ± 0.188 μm/yr, respectively. Slopes of RNFL thickness changes in these groups were −0.514 ± 0.248, −0.520 ± 0.133, and −0.528 ± 0.188 μm/yr, respectively. Slopes of RNFL thickness changes in these groups were −0.514 ± 0.248, −0.520 ± 0.133, and −0.528 ± 0.188 μm/yr, respectively. Slopes of RNFL thickness changes in these groups were −0.514 ± 0.248, −0.520 ± 0.133, and −0.528 ± 0.188 

Conclusions

Refractive error did not affect the physiologic thinning rate of RNFL when assessed by SD OCT.

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

PURPOSE

To investigate the natural clinical course and the risk factors of visual field (VF) progression in untreated normal-tension glaucoma (NTG) with myopia with a minimum 3-year follow-up.

DESIGN

Retrospective cohort study.

METHODS

Kaplan-Meier survival analysis and log-rank test were used to compare survival experiences between the groups. The hazard ratios (HRs) for the associations between potential risk factors and glaucomatous progression were determined using Cox proportional hazards model.

RESULTS

The average follow-up period for the included 97 patients was 71.1 ± 29.7 months and 32 eyes showed progression during the observation period. In NTG with myopia, Kaplan-Meier survival curve showed progression cases in 10.3% at 36 months and 24.8% at 60 months. When age and disc tilt direction were classified into 2 groups, a higher cumulative probability of progression was observed in those aged ≤50 years than >50 years (P = .001) and in those with disc tilt direction <45 degrees than disc tilt direction ≥45 degrees (P = .002). In Cox proportional hazards model, younger age, presence of disc hemorrhage, and more temporally tilted disc or parapapillary atrophy were associated with progression.

CONCLUSIONS

NTG with myopia seems to have a slow progression rate even without glaucoma medications. Only 10.3% and 24.8% of patients showed VF progression at 3 years and 5 years of follow-up in untreated NTG with myopia. To predict VF progression in untreated NTG with myopia, it seems that age and disc morphology should be considered.

Effect of Antiplatelet/Anticoagulant Use on Glaucoma Progression in Eyes With Optic Disc Hemorrhage

PURPOSE

To assess whether the use of antiplatelets (APs)/anticoagulants (ACs) affects glaucoma progression in eyes with optic disc hemorrhage (DH).

METHODS

One hundred and nineteen eyes from 119 patients with primary open-angle glaucoma in whom a DH was observed at least once during the follow-up period (mean follow-up duration: 6.2 y) were included in this retrospective observational study. Cox proportional hazard models were used to identify the association between putative factors, including AP/AC use, and glaucoma progression. Glaucoma progression was assessed on the basis of changes noted on serial optic disc and retinal nerve fiber layer photographs or changes in the visual field.

RESULTS

Nineteen of the 119 patients took AP/AC drugs daily [AP/AC use group (AG)], while the others did not [no use group (NG)]. The follow-up period to progression was significantly different between the 2 groups (61.2±23.5 mo for the AG and 47.6±22.0 mo for the NG; P=0.016). Kaplan-Meier analysis revealed a greater cumulative probability of glaucoma progression in the NG than in the AG, with borderline statistical significance (P=0.081). Higher mean intraocular pressure during the follow-up period was a risk factor for glaucoma progression (hazard ratio, 1.107; P=0.014), while AP/AC drug use protected against glaucoma progression (hazard ratio, 0.576; P=0.046).

CONCLUSIONS

According to our result, use of AP/AC drugs was associated with lower risk of glaucoma progression in eyes with DH.

Sub-classification of myopic glaucomatous eyes according to optic disc and peripapillary features

Purpose

To investigate the sub-classification of myopic glaucomatous eyes by optic disc and peripapillary features.

Methods

Optic disc tilt and torsion were determined from retinal nerve fiber layer photographs. Based on the location of the Bruch’s membrane (BM) opening within the β-zone of the peripapillary atrophy (PPA) area, the widths of β-zone PPA (PPA1W), PPA_+BM (PPA2W), and PPA_-BM (PPA3W) were measured with enhanced depth imaging spectral-domain optical coherence tomography. Cluster analysis that employed partitioning around medoids was performed with these parameters, the presence of inward rotation of BM ending axial length (AXL), and central corneal thickness.

Results

A total of 115 eyes (AXL≥24 mm) were included. Two clusters produced maximum overall silhouette widths (average = 0.43). Visual field (VF) mean deviation was not different between cluster 1 (52 eyes; -4.02±3.01 dB) and cluster 2 (63 eyes; -5.21±5.62 dB; p = 0.174). In cluster 1 compared to cluster 2, optic disc tilt was significantly greater, PPA1W and PPA3W were longer, and AXL was longer (all p<0.001). The presence of an inward rotation of BM ending was more frequent in cluster 2 (p = 0.043). Forty-one eyes (78.8%) in cluster 1 had superior VF defects while 10 eyes (19.2%) had inferior defects, and only one eye (2%) had defects in both hemifields. Eyes in cluster 2 were more evenly distributed: 55.6% had superior defects, 34.9% had inferior defects, and 9.5% had defects in both hemifields (p = 0.023).

Conclusions

Myopic glaucomatous eyes characterized by optic disc and peripapillary configurations can be classified as two distinct types, and the most distinct difference between the two was degree of optic disc tilt and width of PPA. The location of VF defects were also significantly different between two clusters.