Correlations between the optic nerve head morphology and ocular biometrics in highly myopic eyes

Using choroidal thickness to detect myopic macular degeneration

AIM

To explore the usage of choroidal thickness measured by swept-source optical coherence tomography (SS-OCT) to detect myopic macular degeneration (MMD) in high myopic participants.

METHODS

Participants with bilateral high myopia (≤-6 diopters) were recruited from a subset of the Guangzhou Zhongshan Ophthalmic Center-Brien Holden Vision Institute High Myopia Cohort Study. SS-OCT was performed to determine the choroidal thickness, and myopic maculopathy was graded by the International Meta-Analysis for Pathologic Myopia (META-PM) Classification. Presence of MMD was defined as META-PM category 2 or above.

RESULTS

A total of 568 right eyes were included for analysis. Eyes with MMD (n=106, 18.7%) were found to have older age, longer axial lengths (AL), higher myopic spherical equivalents (SE), and reduced choroidal thickness in each Early Treatment Diabetic Retinopathy Study (ETDRS) grid sector (P<0.001). The area under the receiver operating characteristic (ROC) curves (AUC) for subfoveal choroidal thickness (0.907) was greater than that of the model, including age, AL, and SE at 0.6249, 0.8208, and 0.8205, respectively. The choroidal thickness of the inner and outer nasal sectors was the most accurate indicator of MMD (AUC of 0.928 and 0.923, respectively). An outer nasal sector choroidal thickness of less than 74 µm demonstrated the highest odds of predicting MMD (OR=33.8).

CONCLUSION

Choroidal thickness detects the presence of MMD with high agreement, particularly of the inner and outer nasal sectors of the posterior pole, which appears to be a biometric parameter more precise than age, AL, or SE.

Quantitative analysis of optic disc changes in school-age children with ametropia based on artificial intelligence

AIM

To explore changes in the optic disc and peripapillary atrophy (PPA) in school-age children with ametropia using color fundus photography combined with artificial intelligence (AI) technology.

METHODS

Based on the retrospective case-controlled study, 226 eyes of 113 children aged aged 6-12y were enrolled from October 2021 to May 2022. According to the results of spherical equivalent (SE), the children were divided into four groups: low myopia group (66 eyes), moderate myopia group (60 eyes), high myopia group (50 eyes) and emmetropia control group (50 eyes). All subjects underwent un-aided visual acuity, dilated pupil optometry, best-corrected visual acuity (BCVA), intraocular pressure, ocular axis measurement and color fundus photography.

RESULTS

The width of PPA, horizontal diameter ratio of PPA to the optic disc and area ratio of PPA to the optic disc were significantly different among the four groups (P<0.05). The width of the nasal and temporal neuroretinal rim, the roundness of the optic disc, the height of PPA, the vertical diameter ratio of PPA to the optic disc, and the average density of PPA in the high myopia group were significantly different compared with the other three groups (P<0.05). There were strong negative correlations between SE and area ratio of PPA to the optic disc (r=-0.812, P<0.001) and strong positive correlation between axial length (AL) and area ratio of PPA to the optic disc (r=0.736, P<0.001).

CONCLUSION

In school-age children with high myopia, the nasal and temporal neuroretinal rims are narrowed and even lost, which have high sensitivity. The area ratio of the PPA to the optic disc could be used as an early predictor of myopia progression, which is of great significance for the development prevention and management of myopia.

Comparison of Optic Disc Ovality Index and Rotation Angle Measurements in Myopic Eyes Using Photography and OCT Based Techniques

Purpose

To compare optic nerve head (ONH) ovality index and rotation angle measurements based on semi-automated delineation of the clinical ONH margin derived from photographs and automated BMO configuration derived from optical coherence tomography (OCT) images in healthy and glaucomatous eyes with high-, mild- and no axial myopia.

Methods

One hundred seventy-five healthy and glaucomatous eyes of 146 study participants enrolled in the Diagnostic Innovations in Glaucoma Study (DIGS) with optic disc photographs and Spectralis OCT ONH scans acquired on the same day were stratified by level of axial myopia (non-myopic [n = 56, axial length (AL) <24 mm], mild-myopic [n = 58, AL 24–26 mm] and high-myopic [n = 32, AL >26 mm]. The clinical disc margin of each photograph was manually annotated, and semi-automated measurements were recorded of the ovality index and rotation angle based on a best-fit ellipse generated using ImageJ software. These semi-automated photograph-based measurements were compared to ovality index and rotation angle generated from custom automated BMO-based analysis using segmented OCT ONH volumes. R² values from linear mixed effects models were used to describe the associations between semi-automated, photograph-based and automated OCT-based measurements.

Results

Average (95% CI) axial length was 23.3 (23.0, 23.3) mm, 24.8 (24.7, 25.0) mm and 26.8 (26.6, 27.0) mm in non-myopic, mild-myopic and high-myopic eyes, respectively (ANOVA, p ≤ 0.001 for all). The R² association (95% CI) between semi-automated photograph-based and automated OCT-based assessment of ONH OI for all eyes was [0.26 (0.16, 0.36); p < 0.001]. This association was weakest in non-myopic eyes [0.09 (0.01, 0.26); p = 0.02], followed by mild-myopic eyes [0.13 (0.02, 0.29); p = 0.004] and strongest in high-myopic eyes [0.40 (0.19, 0.60); p < 0.001]. No significant associations were found between photography- and OCT-based assessment of rotation angle with R² values ranging from 0.00 (0.00, 0.08) in non-myopic eyes to 0.03 (0.00, 0.21) in high-myopic eyes (all associations p ≥ 0.33).

Conclusions

Agreement between photograph-based and automated OCT-based ONH morphology measurements is limited, suggesting that these methods cannot be used interchangeably for characterizing myopic changes in the ONH.

Quantification of an oval optic disc in relation to myopic foveoschisis using swept-source optical coherence tomography

Background

To investigate the relationship between an oval optic disc and the occurrence of myopic foveoschisis (MF) using swept-source optic coherence tomography (SS-OCT).

Methods

Fifty eyes of 25 patients with unilateral MF were included in this retrospective observational study. The biometric features of the optic disc and peripapillary structures were evaluated using SS-OCT.

Results

The ovality index (OI) of the optic disc was significantly smaller (P = 0.003) and the optic disc tilt angle was greater (P = 0.023) in the eyes with MF than in the contralateral eyes. The optic disc tilt angle was significantly correlated with the OI (P = 0.000). Generalized estimating equation (GEE) model (linear regression) demonstrated that spherical equivalent refraction (P = 0.001), narrow macular staphyloma (P = 0.001) and the occurrence of MF (P = 0.026) were the independent factors associated with the OI. Narrow macular staphyloma was more frequent (P = 0.020) and the staphyloma was deeper (P = 0.006) in eyes with MF. GEE model (logistic regression) revealed that narrow macular staphyloma was the only independent factor related to the occurrence of MF (P = 0.013).

Conclusions

An oval optic disc in eyes with MF resulted from the increased tilt around the vertical disc axis. The optic disc tilt was related to narrow macular staphyloma, which was the only independent factor associated with the occurrence of MF. The clinical relevance needs further exploration through longitudinal analysis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02319-9.

The influence of axial myopia on optic disc characteristics of glaucoma eyes

This study characterizes differences in glaucomatous eyes with and without high axial myopia using custom automated analysis of OCT images. 452 eyes of 277 glaucoma patients were stratified into non (n = 145 eyes), mild (n = 214 eyes), and high axial myopia (axial length (AL) > 26 mm, n = 93 eyes). Optic disc ovality index, tilt and rotation angle of Bruch´s membrane opening (BMO) and peripapillary choroidal thickness (PCT) were calculated using automated and deep learning strategies. High myopic optic discs were more oval and had larger BMO tilt than mild and non-myopic discs (both p < 0.001). Mean PCT was thinnest in high myopic eyes followed by mild and non-myopic eyes (p < 0.001). BMO rotation angle, global retinal nerve fiber layer (RNFL) thickness and BMO-minimum rim width (MRW) were similar among groups. Temporal RNFL was thicker and supranasal BMO-MRW was thinner in high myopic eyes. BMO tilt and PCT showed moderate and temporal RNFL and nasal BMO-MRW showed weak but significant associations with AL in multivariable analyses (all p < 0.05). Large BMO tilt angle and thin PCT are characteristics of highly myopic discs and were not associated with severity of glaucoma. Caution should be exercised when using sectoral BMO-MRW and RNFL thickness for glaucoma management decisions in myopic eyes.