Myopia: Histology, clinical features, and potential implications for the etiology of axial elongation

Myopia and Rate of Peripapillary Retinal Nerve Fiber Layer Thickness in Diabetic Patients Without Retinopathy: A 2-Year Longitudinal Study

PURPOSE

The aim of this study was to investigate the association between myopia and longitudinal changes in peripapillary retinal nerve fiber layer (pRNFL) thickness in type 2 diabetic patients without diabetic retinopathy (DR).

METHODS

A total of 1069 participants with a median follow-up time of 1.9 years were included in this study. The participants were categorized into four groups based on the presence of myopia (≤ -0.5 diopter [D]) and diabetes without DR, including a control group (n = 412), diabetes group (n = 416), myopia group (n = 115), and diabetes + myopia group (n = 126). Peripapillary average and sectoral RNFL measurements were obtained using 6 × 6 mm swept-source optical coherence tomography (SS-OCT) scans centered at the optic disc. The change rate of pRNFL, adjusted for age and sex, was calculated and compared among the four groups to investigate the impact of myopia and diabetes.

RESULTS

The baseline estimated pRNFL thickness after adjustment for covariates was 113.7 μm, 116.2 μm, 108.0 μm, and 105.6 μm in the control, diabetes, myopia, and diabetes + myopia group, respectively (diabetes > control > myopia = diabetes + myopia, p < 0.001). The respective average pRNFL loss in the four groups was -0.48 μm/year, -1.11 μm/year, -1.23 μm/year, and -2.62 μm/year (all p < 0.01). The diabetes + myopia group exhibited a greater rate of average pRNFL reduction compared to the other groups (all p < 0.001). Multivariate analysis using a linear mixed-effects model showed that age, diabetes, axial length (AL), and baseline pRNFL thickness were significantly associated with the rate of average pRNFL reduction.

CONCLUSIONS

The diabetes group showed a faster rate of average pRNFL thickness reduction compared to healthy controls, regardless of the presence of myopia. The average pRNFL thickness decreased more rapidly when diabetes and myopia were present simultaneously than in the individual diabetes or myopia group. Both diabetes and myopia were associated with accelerated pRNFL loss.

Association Between Myopia and Pupil Diameter in Preschoolers: Evidence from a Machine Learning Approach Based on a Real-World Large-Scale Dataset

INTRODUCTION

Previous studies have explored the connections between various ocular biological parameters with myopia. Our previous study also found that pupil data can predict the myopic progression during the interventions for myopia. However, studies exploring the association between pupil diameter and myopia in preschoolers with myopia were lacking. Hence this study was aimed to investigate the association between pupil diameter and myopia in preschoolers with myopia based on a real-world, large-scale dataset.

METHODS

Data containing 650,671 preschoolers were collected from a total of 1943 kindergartens in Shenzhen, China. Refraction and pupil parameters were collected. After data filtering, the occurrence of myopia and its association with age, gender, pupil diameter, and other variables, were analyzed. Random forest (RF) and eXtreme gradient boosting (XGBoost) were selected from seven machine learning algorithms to build the model. The mean decrease accuracy (MDA), mean decrease Gini (MDG), and gain feature importance (GFI) techniques were employed to quantify the importance of pupil diameter and other features.

RESULTS

After the assessments, 51,325 valid records with complete pupil data were included, and 3468 (6.76%) were identified as myopia based on the calculated cycloplegic refraction. Preschoolers with myopia presented reduced pupil diameter and greater variation (5.00 ± 0.99 mm) compared to non-myopic preschoolers (6.22 ± 0.67 mm). A nonlinear relationship was found according to the scatterplots between pupil diameter and refraction (R2 = 0.14). Especially preschoolers with myopia had reduced pupil diameter compared to emmetropic preschoolers, but hyperope did not experience additional pupil enlargement. After adjusting for other covariates, this relationship is still consistent (P < 0.001). XGBoost and RF algorithms presented the highest performance and validated the importance of pupil diameter in myopia.

CONCLUSIONS

Based on a real-world large-scale dataset, the current study illuminated that preschoolers with myopia had a reduced pupil diameter compared to emmetropic preschoolers with a nonlinear pattern. Machine learning algorithms visualized and validated the pivotal role of pupil diameter in myopia.

TRIAL REGISTRATION

chictr.org Identifier: ChiCTR2200057391.

Retinal Changes From Hyperopia to Myopia: Not All Diopters Are Created Equal

Purpose

To quantitatively characterize retinal changes across different quantiles of refractive error in 34,414 normal eyes of 23,064 healthy adults in the UK Biobank.

Methods

Twelve optic disc (OD), foveal and vascular parameters were derived from color fundus photographs, correcting for ocular magnification as appropriate. Quantile regression was used to test the independent associations between these parameters and spherical equivalent refraction (SER) across 34 refractive quantiles (high hyperopia to high myopia)-controlling for age, sex and corneal radius.

Results

More negative SER was nonlinearly associated with greater Euclidian (largely horizontal) OD-fovea distance, larger OD, less circular OD, more obliquely orientated OD (superior pole tilted towards the fovea), brighter fovea, lower vascular complexity, less tortuous vessels, more concave (straightened out towards the fovea) papillomacular arterial/venous arcade and wider central retinal arterioles/venules. In myopia, these parameters varied more strongly with SER as myopia increased. For example, while every standard deviation (SD) decrease in vascular complexity was associated with 0.63 D (right eye: 95% confidence interval [CI], 0.58-0.68) to 0.68 D (left eye: 95% CI, 0.63-0.73) higher myopia in the quantile corresponding to -0.60 D, it was associated with 1.61 D (right eye: 95% CI, 1.40-1.82) to 1.70 D (left eye: 95% CI, 1.56-1.84) higher myopia in the most myopic quantile. OD-fovea angle (degree of vertical separation between OD and fovea) was found to vary linearly with SER, but the magnitude was of little practical importance (less than 0.10 D variation per SD change in angle in almost all refractive quantiles) compared with the changes in OD-fovea distance.

Conclusions

Several interrelated retinal changes indicative of an increasing (nonconstant) rate of mechanical stretching are evident at the posterior pole as myopia increases. These changes also suggest that the posterior pole stretches predominantly in the temporal horizontal direction.

Global prevalence of myopic macular degeneration in general population and patients with high myopia: A systematic review and meta-analysis

The prevalence of myopic macular degeneration (MMD) in the general population and patients with high myopia worldwide has not been fully investigated. Therefore, we screened all population-based studies that reported the prevalence of MMD, and pooled prevalence of MMD using a random-effect model. Subgroup analyses were performed to explore the differences in MMD prevalence in the general population and patients with high myopia according to ethnicity, region of residence (urban/rural), and grading system. Finally, 16 studies were included in this meta-analysis. Results obtained from 2,963 patients from seven countries on four continents indicated that the pooled prevalence of MMD in patients with high myopia was 49.0% (95% CI: 31.5%-66.7%). Results obtained from 71,052 participants from 10 countries on four continents suggested that the pooled prevalence of MMD in the general population was 1.7% (95% CI: 1.1%-2.6%). In the general population, living in urban areas and East Asians were associated with a high prevalence of MMD. Among patients with high myopia, only East Asians were at a higher risk of developing MMD. In conclusion, MMD was particularly prevalent in patients with high myopia. Compared with Europeans, East Asians (Chinese and Japanese) have a higher propensity of developing MMD, both in the general population and in patients with high myopia. It remains unclear whether the higher prevalence of MMD in patients with high myopia in East Asia is caused by differences in given age or given degree of myopia.Systematic review registration number: 202270014 (INPLASY.COM).

Degradation of Photopic and Mesopic Contrast Sensitivity Function in High Myopes With Partial Posterior Vitreous Detachment

Purpose

The purpose of this study was to evaluate the effects of posterior vitreous detachment (PVD) on visual quality in patients with high myopia, as well as investigate the associated factors of photopic and mesopic contrast sensitivity function (CSF) in high myopia.

Methods

Visual quality was comprehensively assessed in patients with high myopia. Visual acuity, contrast sensitivity (CS) at four spatial frequencies (3, 6, 12, and 18 cycles per degree [c.p.d.]) under photopic and mesopic conditions, as well as the modulation transfer function cutoff value (MTFcutoff), the objective scatter index (OSI), the Strehl ratio (SR), and internal aberrations, were measured in this cross-sectional study.

Results

This study included 94 eyes from 47 subjects with bilateral high myopia, including 23 eyes with complete PVD (cPVD), 21 eyes with partial PVD (pPVD), and 50 eyes without PVD (nPVD). There was no significant difference in visual quality between the cPVD group and the nPVD group. Whereas in eyes with pPVD, there was a degradation of overall photopic CSF (versus nPVD, P = 0.048), photopic CS at 3 c.p.d. (versus cPVD, P = 0.009 and versus nPVD, P = 0.032), photopic CS at 18 c.p.d. (versus nPVD, P = 0.033), overall mesopic CSF (versus nPVD, P = 0.033), and secondary astigmatism (versus cPVD, P = 0.044). Under photopic conditions, the factors affecting CSF were pPVD and SR, whereas the factors affecting mesopic CSF were pPVD, OSI, and ganglion cell-inner plexiform layer thickness.

Conclusions

The pPVD impaired visual quality in patients with high myopia compared to nPVD or cPVD, and pPVD could be a factor explaining CSF at both photopic and mesopic illumination.

Translational Relevance

Clinicians need to closely monitor patients with high myopia with pPVD due to the potential decline in visual quality and the development of vitreoretinal disorders.

Prevalence of Myopic Maculopathy Among the Very Old: The Ural Very Old Study

Purpose

To assess the prevalence of myopic macular degeneration (MMD) in very old individuals.

Methods

The population-based Ural Very Old Study (UVOS) included 1526 (81.1%) of 1882 eligible inhabitants aged ≥85 years. Assessable fundus images were available for 930 (60.9%) individuals (mean age, 88.6 ± 2.7 years). MMD was defined by macular patchy atrophies (i.e., MMD stage 3 and 4 as defined by the Pathologic Myopia Study Group).

Results

MMD prevalence was 21 of 930 (2.3%; 95% CI, 1.3-3.3), with 10 individuals (1.1%; 95% CI, 0.4-1.7) having MMD stage 3 and 11 participants (1.2%; 95% CI, 0.5-1.9) MMD stage 4 disease. Within MMD stage 3 and 4, prevalence of binocular moderate to severe vision impairment was 4 of 10 (40%; 95% CI, 31-77) and 7 of 11 (64%; 95% CI, 30-98), respectively, and the prevalence of binocular blindness was 2 of 10 (20%; 95% CI, 0-50) and 3 of 11 (27%; 95% CI, 0-59), respectively. In minor myopia (axial length, 24.0 to <24.5 mm), moderate myopia (axial length, 24.5 to <26.5 mm), and high myopia (axial length, ≥26.5 mm), MMD prevalence in the right eyes was 0 of 46 eyes (0%), 3 of 40 eyes (8%; 95% CI, 0-16), and 7 of 9 (78%; 95% CI, 44-100), respectively; MMD prevalence in the left eyes was 1 in 48 eyes (2%; 95% CI, 0-6), 4 of 36 eyes (11%; 95% CI, 0-22), and 3 of 4 eyes (75%; 95% CI, 0-100), respectively. In multivariable analysis, a higher MMD prevalence (odds ratio, 8.89; 95% CI, 3.43-23.0; P < 0.001) and higher MMD stage (beta, 0.45; B, 19; 95% CI, 0.16-0.22; P < 0.001) were correlated with longer axial length but not with any other ocular or systemic parameter.

Conclusions

MMD prevalence (stages 3 and 4) in very old individuals increased 8.89-fold for each mm axial length increase, with a prevalence of ≥75% in highly myopic eyes. In old age, highly myopic individuals have a high risk of eventually developing MMD with marked vision impairment.

Association between Axial Length to Corneal Curvature Radius Ratio and Myopia in Adult Patients

Purpose

To analyze the distribution characteristics of axial length to corneal curvature radius ratio (AL/CR) and other ocular biometric parameters in adult myopia patients and their association with myopia.

Methods

A cross-sectional study was conducted among patients with no eye diseases except ametropia who attended the optometry clinic of the First Affiliated Hospital of Hainan Medical College from January 2022 to June 2022. In total, 187 eyes (right eye) of 187 myopic patients aged 18-35 years were selected by random sampling. Based on the results of spherical equivalent (SE, (D)) obtained by postdilation optometry, all subjects were divided into three groups: mild myopia (≤-0.50D and >-3.00D, 42 eyes), moderate myopia (≤-3.00D and >-6.00D, 80 eyes), and high myopia (≤-6.00D, 65 eyes). The axial length (AL), corneal curvature radius (CR), and AL/CR were measured and compared between the three groups. The association between AL and AL/CR of the eye and SE was analyzed by multiple linear regression. Also, the predictive ability of AL/CR for high myopia was investigated by ROC curve.

Results

There were no statistically significant differences in age, gender, or intraocular pressure between the three groups. The mean values of AL/CR in mild, moderate, and high myopia groups were 3.17 ± 0.06, 3.31 ± 0.08, and 3.43 ± 0.10, respectively, and the difference between the groups was statistically significant (P < 0.001). Linear regression analysis showed that both AL and AL/CR were strongly negatively correlated with SE (P < 0.05), while CR had a weak positive correlation with SE without statistically significant differences (P > 0.05). The adjusted linear regression equation shows that for every 0.1 unit increase in AL/CR, SE increases by 1.54 D. Compared with 0.830 (95% confidence interval: 0.769 to 0.900) for AL, the area under ROC curve of AL/CR was 0.896 (95% confidence interval: 0.851 to 0.941), indicating that the diagnostic value of AL/CR for high myopia was higher than that of AL (P <  0.01). When the Youden index reached its maximum (0.626), the AL/CR cutoff point was 3.309, and the sensitivity and specificity were 0.954 and 0.672, respectively.

Conclusion

This study showed that AL and AL/CR in adult myopia patients were significantly negatively correlated with SE, and the corralation between AL/CR and SE is greater than that between AL and SE. Therefore, AL/CR can be used to analyze the dynamic changes of SE in the development of adult myopia independently of optometry on a certain basis, and it is especially suitable for the diagnosis of high myopia in adults. This trial is registered with ChiCTR2300069070.

Influencing factors comparing different vault groups after phakic implantable collamer lens implantation: review and meta-analysis

BACKGROUND

Studies on the factors affecting vault after posterior chamber phakic Implantable Collamer Lens (ICL) have been carried out, but most of them are single-centered and subjective selections of parameters. The present study aimed to systematically analyze the factors for vault.

METHODS

A systematic review of case series, case-control, and cohort studies derived from the articles published in PubMed, the Cochrane Library, Embase, Web of Science, CNKI, CBM, Wanfang and VIP, as well as ClinicalTrials, which were conducted to search for studies on factors of vault using four core terms: phakic intraocular lenses, vault, risk factor and observational study, from January 01, 1997, to February 20, 2023. The included studies were meta-analyzed quantitatively and described qualitatively. Subsequently, meta-regression and subgroup analysis were used.

RESULTS

We identified 13 studies (1,607 subjects), and 14 factors were considered. Meta-analysis showed that anterior chamber depth (ACD), horizontal corneal white-to-white (hWTW), ICL-size, and age are dual effects of the abnormal vaults; anterior chamber volume (ACV) and lens thickness (LT) are a one-way effect; while axial length (AL), ICL- spherical equivalent (ICL-SE) and Km are insignificant. In addition, descriptive analysis of anterior chamber angle (ACA), horizontal sulcus to sulcus (hSTS), ciliary processes height (T value), crystalline lens rise (CLR), and gender showed that all factors except gender tend to have significant effects on vault. Sensitivity analysis showed stable combined results. Country and design respectively affect the heterogeneity in ACD and ICL-size at low vault, while design affects the heterogeneity in ACD at high vault. No publication bias exists.

CONCLUSIONS

Vault after ICL is related to multiple factors, especially anterior segmental biologic parameters, and they are weighted differently. We hope to provide a reference for the selection and adjustment of ICL.

Effectiveness of a Spectacle Lens with a Specific Asymmetric Myopic Peripheral Defocus: 12-Month Results in a Spanish Population

BACKGROUND

Different designs of ophthalmic lenses have been studied to control the progression of myopia in children. This study aims to evaluate the short-term efficacy of a new design of ophthalmic lens with asymmetric myopic peripheral defocus (MPDL) on myopia progression in children compared to a control group wearing a single-vision lens (SVL).

METHODS

Children aged 5 to 12 with myopia up to -0.50 D, astigmatism and anisometropia under 1.50 D, and corrected visual acuity over 20/20 were randomized to either the study group (MPDL) or control group (SVL). The myopia progression was evaluated by measuring axial length (AL) growth (IOL Master; Zeiss) over a period of one year.

RESULTS

Ninety-two subjects were recruited. Forty-six children were randomly assigned to the control group, and 46 to the study group. In total, 83 children completed the clinical trial, with a mean age of 10.81 [9.53-11.92] years, among which 59.04% were female. After one year of treatment, there was less AL elongation in the study group compared to the control group (0.16 ± 0.16 mm vs. 0.24 ± 0.16 mm, p = 0.034).

CONCLUSIONS

The MPDL significantly reduced the absolute growth of AL by 39% (p = 0.014) and relative growth of AL by 37.3% (p = 0.012) after 12 months in comparison to the control group in a Spanish population.

A Novel Exploration of the Choroidal Vortex Vein System: Incidence and Characteristics of Posterior Vortex Veins in Healthy Eyes

Purpose

The purpose of this study was to investigate the incidence and characteristics of posterior vortex veins (PVVs) in healthy eyes and explore their relationship with age and refractive status.

Methods

This retrospective cross-sectional analysis encompassed 510 eyes from 255 consecutive healthy participants. Wide-field optical coherence tomography angiography (WF-OCTA) imaging was used to assess the presence of PVVs. Eyes were classified according to refractive status (emmetropia, low and moderate myopia, and high myopia) and age (minors and adults). The incidence and characteristics of eyes with PVVs were analyzed.

Results

Participants (mean age = 30.60 ± 21.12 years, 47.4% men) showed a mean refractive error of -2.83 ± 3.10 diopters (D; range = -12.00 to +0.75). PVVs were observed in 16.1% (82/510) of eyes. Of these, 39% (32/82) had PVVs in one eye and 61% (50/82) in both eyes. The mean number of PVVs per eye was 1.65 ± 1.05 (range = 1-6). PVVs are mainly around the optic disc (78%, 64/82) of eyes with PVVs and less in the macular area (6.1%, 5/82) or elsewhere (15.9%, 13/82). PVV incidence correlated with refractive status: 10.3% (22/213) in emmetropia, 16.6% (31/187) in low and moderate myopia, and 26.4% (29/110) in high myopia (P = 0.001), but not with age. Refractive status was the key predictor of PVV occurrence (odds ratio [OR] = 1.45, 95% confidence interval [CI] = 1.02-2.06, P = 0.038).

Conclusions

This study confirms PVVs' presence in healthy eyes, highlighting their inherent existence and susceptibility to alterations due to refractive conditions. These findings enhance our understanding of the vortex vein system and its distribution within the eyes.

Bruch's membrane and Brücke's muscle in the pars plana region

PURPOSE

To examine Bruch's membrane (BM) in association with the longitudinal part of the ciliary muscle (LPCM) in the pars plana region.

METHODS

Using light microscopy, we histomorphometrically assessed BM and the LPCM in the pars plana region.

RESULTS

The histomorphometric study included 51 eyes (51 patients; mean age: 60.8 ± 15.0 years; axial length: 26.0 ± 3.3 mm; range: 21.0-36.0 mm). The LPCM (total length: 4.60 ± 1.10 mm) ended 1.15 ± 0.56 mm anterior to the ora serrata. Within the pars plana region, the LPCM (length: 2.58 ± 0.98 mm) had direct contact with BM for 1.95 ± 0.99 mm (71.1 ± 18.4% of the BM undersurface), while a capillary layer was interposed between the BM and the LPCM for 0.70 ± 0.40 mm (29.0 ± 18.4%). In the pars plana region free of LPCM close to the ora serrata, the percentage of BM covered by the capillary layer was higher than in the pars plana region containing the LPCM (63.0 ± 42.1% vs. 29.0 ± 18.4%; p < 0.001). At the LPCM end, BM was in direct contact with a collagenous tissue from the LPCM and was focally thickened as compared to BM with an underlying capillary layer (9.5 ± 5.3 μm vs. 4.3 ± 1.2 μm; p < 0.001).

CONCLUSIONS

The direct contact of BM with the LPCM in the pars plana in association with focal BM thickening at the LPCM end suggests an insertion of LPCM on the BM. Taking into account the biomechanical strength of BM, it may imply a functional unit of the LPCM with BM in the process of accommodation with a secondary movement of the posterior BM and tertiary thickening of the subfoveal choroidal space.

Optic Nerve Head Curvature Flattening Is Associated with Central Visual Field Scotoma

This study aimed to develop a new index, the average curvature ratio (ACR), to represent the optic nerve head (ONH) tilting and investigate its clinical relevance. Myopic eyes were included and divided into two subgroups: flat ONH (ACR < 1.0) and convex ONH (ACR ≥ 1.0). The occurrences of central and peripheral visual field (VF) defects were compared between the two groups. A total of 375 myopic eyes were recruited, and 231 and 144 eyes were included in the flat and convex ONH groups, respectively. Central scotoma occurred more frequently in the flat ONH group. According to the Patella-Anderson criteria, the number of eyes with central scotoma was 103 (44.6%) in the flat and 44 (30.6%) in the convex ONH groups (p = 0.009). According to Kook's criteria, the number of eyes with central scotoma was 122 (52.8%) in the flat and 50 (34.7%) in the convex ONH groups (p < 0.001). Peripheral scotoma was not significantly different between the groups. In the correlation analysis, the ACR was positively correlated with spherical equivalence, but not with axial length or central corneal thickness. The ACR reflects the degree of the ONH tilt and is a good index for estimating central VF damage in myopic eyes.

Three cases of macular retinal detachment exacerbated during follow-up with myopic foveoschisis around myopic choroidal neovascularization

Purpose

Myopic choroidal neovascularization (CNV) and myopic traction maculopathy are major complications of pathologic myopia, and myopic foveoschisis (MF) is one of several symptoms that can be included under the general term "myopic traction maculopathy"; however, only a few cases will have MF around the myopic CNV. We report three cases with MF around myopic CNV that followed different clinical courses observed using swept-source optical coherence tomography.

Observations

Case 1 was a 69-year-old woman with an axial length of 29.71 mm, myopic CNV, and MF in the left eye. One month after intravitreal injection of ranibizumab (IVR), a macular retinal detachment (RD) expanded. Vitrectomy and gas tamponade were performed during month 2; the macular RD and MF resolved gradually thereafter. Case 2 was a 54-year-old man with an axial length of 30.59 mm, myopic CNV, and MF in the right eye; after IVR, a macular RD developed and gradually expanded until month 4; the RD and MF resolved spontaneously and resolved during month 8. Case 3 was a 66-year-old woman with an axial length of 28.63 mm, myopic CNV, and MF in the left eye. A macular RD expanded 1 month after a previous vitrectomy for MF; after intravitreal injection of aflibercept, the macular RD and MF resolved gradually in month 12. In all cases, the CNV was accompanied by subretinal fluid, and two of the three cases had outer lamellar holes.

Conclusion and Importance

The MF around the myopic CNV may lead to exacerbated MF and RD during follow-up, and the subretinal fluid caused by the CNV might facilitate MF progression. Since this condition is rare, further investigation of this entity is needed to determine appropriate management.

Collagen Mimetic Peptides Promote Repair of MMP-1-Damaged Collagen in the Rodent Sclera and Optic Nerve Head

The structural and biomechanical properties of collagen-rich ocular tissues, such as the sclera, are integral to ocular function. The degradation of collagen in such tissues is associated with debilitating ophthalmic diseases such as glaucoma and myopia, which often lead to visual impairment. Collagen mimetic peptides (CMPs) have emerged as an effective treatment to repair damaged collagen in tissues of the optic projection, such as the retina and optic nerve. In this study, we used atomic force microscopy (AFM) to assess the potential of CMPs in restoring tissue stiffness in the optic nerve head (ONH), including the peripapillary sclera (PPS) and the glial lamina. Using rat ONH tissue sections, we induced collagen damage with MMP-1, followed by treatment with CMP-3 or vehicle. MMP-1 significantly reduced the Young's modulus of both the PPS and the glial lamina, indicating tissue softening. Subsequent CMP-3 treatment partially restored tissue stiffness in both the PPS and the glial lamina. Immunohistochemical analyses revealed reduced collagen fragmentation after MMP-1 digestion in CMP-3-treated tissues compared to vehicle controls. In summary, these results demonstrate the potential of CMPs to restore collagen stiffness and structure in ONH tissues following enzymatic damage. CMPs may offer a promising therapeutic avenue for preserving vision in ocular disorders involving collagen remodeling and degradation.

High Myopia Normative Database of Peripapillary Retinal Nerve Fiber Layer Thickness to Detect Myopic Glaucoma in a Chinese Population

PURPOSE

To develop and validate the performance of a high myopia (HM)-specific normative database of peripapillary retinal nerve fiber layer (pRNFL) thickness in differentiating HM from highly myopic glaucoma (HMG).

DESIGN

Cross-sectional multicenter study.

PARTICIPANTS

A total of 1367 Chinese participants (2325 eyes) with nonpathologic HM or HMG were included from 4 centers. After quality control, 1108 eyes from 694 participants with HM were included in the normative database; 459 eyes from 408 participants (323 eyes with HM and 136 eyes with HMG) and 322 eyes from 197 participants (131 eyes with HM and 191 eyes with HMG) were included in the internal and external validation sets, respectively. Only HMG eyes with an intraocular pressure > 21 mmHg were included.

METHODS

The pRNFL thickness was measured with swept-source (SS) OCT. Four strategies of pRNFL-specified values were examined, including global and quadrantic pRNFL thickness below the lowest fifth or the lowest first percentile of the normative database.

MAIN OUTCOMES MEASURES

The accuracy, sensitivity, and specificity of the HM-specific normative database for detecting HMG.

RESULTS

Setting the fifth percentile of the global pRNFL thickness as the threshold, using the HM-specific normative database, we achieved an accuracy of 0.93 (95% confidence interval [CI], 0.90-0.95) and 0.85 (95% CI, 0.81-0.89), and, using the first percentile as the threshold, we acheived an accuracy of 0.85 (95% CI, 0.81-0.88) and 0.70 (95% CI, 0.65-0.75) in detecting HMG in the internal and external validation sets, respectively. The fifth percentile of the global pRNFL thickness achieved high sensitivities of 0.75 (95% CI, 0.67-0.82) and 0.75 (95% CI, 0.68-0.81) and specificities of 1.00 (95% CI, 0.99-1.00) and 1.00 (95% CI, 0.97-1.00) in the internal and external validation datasets, respectively. Compared with the built-in database of the OCT device, the HM-specific normative database showed a higher sensitivity and specificity than the corresponding pRNFL thickness below the fifth or first percentile (P < 0.001 for all).

CONCLUSIONS

The HM-specific normative database is more capable of detecting HMG eyes than the SS OCT built-in database, which may be an effective tool for differential diagnosis between HMG and HM.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Deep learning-based estimation of axial length using macular optical coherence tomography images

Background

This study aimed to develop deep learning models using macular optical coherence tomography (OCT) images to estimate axial lengths (ALs) in eyes without maculopathy.

Methods

A total of 2,664 macular OCT images from 444 patients' eyes without maculopathy, who visited Beijing Hospital between March 2019 and October 2021, were included. The dataset was divided into training, validation, and testing sets with a ratio of 6:2:2. Three pre-trained models (ResNet 18, ResNet 50, and ViT) were developed for binary classification (AL ≥ 26 mm) and regression task. Ten-fold cross-validation was performed, and Grad-CAM analysis was employed to visualize AL-related macular features. Additionally, retinal thickness measurements were used to predict AL by linear and logistic regression models.

Results

ResNet 50 achieved an accuracy of 0.872 (95% Confidence Interval [CI], 0.840-0.899), with high sensitivity of 0.804 (95% CI, 0.728-0.867) and specificity of 0.895 (95% CI, 0.861-0.923). The mean absolute error for AL prediction was 0.83 mm (95% CI, 0.72-0.95 mm). The best AUC, and accuracy of AL estimation using macular OCT images (0.929, 87.2%) was superior to using retinal thickness measurements alone (0.747, 77.8%). AL-related macular features were on the fovea and adjacent regions.

Conclusion

OCT images can be effectively utilized for estimating AL with good performance via deep learning. The AL-related macular features exhibit a localized pattern in the macula, rather than continuous alterations throughout the entire region. These findings can lay the foundation for future research in the pathogenesis of AL-related maculopathy.

Prevalence and Associations of Nonglaucomatous Optic Nerve Atrophy in High Myopia: The Ural Eye and Medical Study

PURPOSE

To assess the prevalence of nonglaucomatous optic nerve atrophy (NGOA) in highly myopic individuals.

DESIGN

Population-based study.

PARTICIPANTS

The Ural Eye and Medical Study included 5899 (80.5%) of 7328 eligible individuals (80.5%).

METHODS

Nonglaucomatous optic nerve atrophy, graded into 5 arbitrary stages, was characterized by decreased visibility of the retinal nerve fiber layer (RNFL) on photographs, neuroretinal rim pallor, abnormally thin retinal arteriole diameter, and abnormally thin peripapillary RNFL as measured by OCT.

MAIN OUTCOME MEASURES

Nonglaucomatous optic nerve atrophy prevalence and degree.

RESULTS

Of 5709 participants (96.9%) with axial length measurements, 130 individuals (2.3%) were highly myopic, of whom 116 individuals (89.2%; age, 57.8 ± 11.1 years; axial length, 27.0 ± 1.2 mm) had available fundus photographs and OCT images and were included into the study. Nonglaucomatous optic nerve atrophy prevalence was 34/116 individuals (29.3%; 95% confidence interval [CI], 21.0-38.0), and mean NGOA degree in eyes with NGOA was 1.7 ± 1.0 arbitrary units. Higher NGOA degree correlated (multivariable analysis; regression coefficient, r2 = 0.59) with longer axial length (β, 0.22; P = 0.007), wider temporal parapapillary γ zone width (β, 0.50; P < 0.001), higher prevalence of diabetes (β, 0.20; P = 0.005), and higher systolic blood pressure (β, 0.15; P = 0.03). Higher NGOA prevalence was associated with longer axial length (odds ratio [OR], 7.45; 95% CI, 2.15-25.7), wider temporal parapapillary γ zone (OR, 6.98; 95% CI, 2.61-18.7), and higher systolic blood pressure (OR, 1.05; 95% CI, 1.01-1.10).

CONCLUSIONS

In this ethnically mixed population from Russia with an age of 40 years or more, high axial myopia showed a relatively high prevalence of NGOA, increasing with longer axial length and wider temporal parapapillary γ zone. For each 1 mm of axial elongation and γ zone widening, the odds for NGOA increased 7.45-fold and 6.98-fold, respectively. The axial elongation-associated and γ zone-related increase in the distance between the retinal ganglion cells and the optic disc may lead to a lengthening and stretching of the retinal ganglion cell axons and may be of importance pathogenetically. In highly myopic eyes, NGOA may be a reason for visual field and central visual acuity loss, unexplainable by myopic macular pathologic features.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Mendelian randomization study confirms causal relationship between myopia and vitreous disorders

PURPOSE

This study aims to investigate the potential bidirectional causal relationship between myopia and vitreous disorders from a genetic perspective, as vitreous disorders have been found to be closely associated with myopia development.

METHODS

To achieve this, a two-sample Mendelian randomization (MR) design was employed. The study utilized pooled statistics from independent genome-wide association studies. Myopia was chosen as the exposure factor, while five different vitreous disorders were considered as outcomes. The primary analytical method was the inverse variance weighting (IVW) method, supplemented by sensitivity analysis.

RESULTS

The study yielded significant findings indicating a positive association between myopia and vitreous disorders. The genetic prediction of myopia consistently demonstrated a positive correlation with vitreous disorders, as evidenced by IVW (odds ratio [OR] = 18.387; P < 0.01), MR Egger (OR = 2784.954; P < 0.01), weighted median (OR = 30.284; P < 0.01), and weighted mode (OR = 57.381; P < 0.01). All sensitivity analyses further validated these associations. Furthermore, a significant association was observed between myopia and other unspecified vitreous body disorders (IVW: OR = 57.729; P < 0.01).

CONCLUSION

Studies mainly conducted in European populations have confirmed that myopia, extending beyond early high myopia, plays a crucial role in influencing vitreous disorders and that there is a unidirectional causal relationship between myopia and vitreous disorders. Additionally, a causal relationship was identified between myopia and other unspecified vitreous disordes. These findings introduce fresh perspectives for the clinical management of unspecified vitreous disorders and contribute to the understanding of the effect of myopia on vitreous disorders. Myopia prevention and treatment will aid in slowing down the process of vitreous liquefaction and subsequently decrease the incidence of malignant eye conditions.

IMI-Nonpathological Human Ocular Tissue Changes With Axial Myopia

Purpose

To describe nonpathological myopia-related characteristics of the human eye.

Methods

Based on histomorphometric and clinical studies, qualitative and quantitative findings associated with myopic axial elongation are presented.

Results

In axial myopia, the eye changes from a spherical shape to a prolate ellipsoid, photoreceptor, and retinal pigment epithelium cell density and total retinal thickness decrease, most marked in the retroequatorial region, followed by the equator. The choroid and sclera are thin, most markedly at the posterior pole and least markedly at the ora serrata. The sclera undergoes alterations in fibroblast activity, changes in extracellular matrix content, and remodeling. Bruch's membrane (BM) thickness is unrelated to axial length, although the BM volume increases. In moderate myopia, the BM opening shifts, usually toward the fovea, leading to the BM overhanging into the nasal intrapapillary compartment. Subsequently, the BM is absent in the temporal region (such as parapapillary gamma zone), the optic disc takes on a vertically oval shape, the fovea-optic disc distance elongates without macular BM elongation, the angle kappa reduces, and the papillomacular retinal vessels and nerve fibers straighten and stretch. In high myopia, the BM opening and the optic disc enlarge, the lamina cribrosa, the peripapillary scleral flange (such as parapapillary delta zone) and the peripapillary choroidal border tissue lengthen and thin, and a circular gamma and delta zone develop.

Conclusions

A thorough characterization of ocular changes in nonpathological myopia are of importance to better understand the mechanisms of myopic axial elongation, pathological structural changes, and psychophysical sequelae of myopia on visual function.

Glaucoma and Myopia: Diagnostic Challenges

The rising global prevalence of myopia is a growing concern for clinicians, as it predisposes patients to severe ocular pathologies including glaucoma. High myopia can be associated with clinical features that resemble glaucomatous damage, which make an accurate glaucoma diagnosis challenging, particularly among patients with normal intraocular pressures. These patients may also present with established visual field defects which can mimic glaucoma, and standard imaging technology is less useful in disease detection and monitoring due to the lack of normative data for these anatomically unique eyes. Progression over time remains the most critical factor in facilitating the detection of early glaucomatous changes, and thus careful longitudinal follow-up of high-risk myopic patients is the most important aspect of management. Here, we review our current understanding of the complex relationship between myopia and glaucoma, and the diagnostic challenges and limitations of current testing protocols including visual field, intraocular pressure, and imaging. Furthermore, we discuss the clinical findings of two highly myopic patients with suspected glaucoma.

Swept-Source OCT Mid-Peripheral Retinal Irregularity in Retinal Detachment and Posterior Vitreous Detachment Eyes

Irregularities in retinal shape have been shown to correlate with axial length, a major risk factor for retinal detachment. To further investigate this association, a comparison was performed of the swept-source optical coherence tomography (SS OCT) peripheral retinal shape of eyes that had either a posterior vitreous detachment (PVD) or vitrectomy for retinal detachment. The objective was to identify a biomarker that can be tested as a predictor for retinal detachment. Eyes with a PVD (N = 88), treated retinal detachment (N = 67), or retinal tear (N = 53) were recruited between July 2020 and January 2022 from hospital retinal clinics in South Australia. The mid-peripheral retina was imaged in four quadrants with SS OCT. The features explored were patient age, eye axial length, and retinal shape irregularity quantified in the frequency domain. A discriminant analysis classifier to identify retinal detachment eyes was trained with two-thirds and tested with one-third of the sample. Retinal detachment eyes had greater irregularity than PVD eyes. A classifier trained using shape features from the superior and temporal retina had a specificity of 84% and a sensitivity of 48%. Models incorporating axial length were less successful, suggesting peripheral retinal irregularity is a better biomarker for retinal detachment than axial length. Mid-peripheral retinal irregularity can identify eyes that have experienced a retinal detachment.