Optic nerve head anatomy in myopia and glaucoma, including parapapillary zones alpha, beta, gamma and delta: Histology and clinical features

Effects of Deep Optic Nerve Head Structures on Bruch's Membrane Opening- Minimum Rim Width and Peripapillary Retinal Nerve Fiber Layer

PURPOSE

To explore the effects of deep optic nerve head (ONH) structures on Bruch's membrane opening (BMO)-minimum rim width (MRW) and peripapillary retinal nerve fiber layer thickness (pRNFLT) in healthy eyes.

DESIGN

Prospective cross-sectional study.

METHODS

Two hundred five healthy eyes of 141 subjects (mean ± standard deviation of age and axial length (AXL): 46.9 ± 10.0 years and 24.79 ± 1.15 mm) were enrolled. Best fit multivariable linear mixed models identified factors associated with BMO-MRW and pRNFLT. Explanatory variables included age, gender, AXL, BMO and anterior scleral canal opening (ASCO) area and ovality, magnitude of BMO and ASCO shift, peripapillary choroidal thickness, lamina cribrosa (LC) parameters, prelaminar thickness, and peripapillary scleral (PPS) angle.

RESULTS

Thinner BMO-MRW was associated with older age, smaller ASCO/BMO offset magnitude, larger BMO area, thinner prelaminar thickness, deeper LC, and thinner pRNFLT (P = .011, <.001, .004, <.001, <.001, <.001 respectively). Thinner pRNFLT was associated with shorter AXL, smaller ASCO area, a more posteriorly bowed PPS, shallower LC and thinner BMO-MRW. (P = .030, .002, .035, .012, <.001 respectively) CONCLUSIONS: BMO-MRW and pRNFLT were influenced by several deep ONH structures such as BMO and ASCO position shift, BMO or ASCO area, prelaminar thickness, PPS bowing and LC depth in addition to patient characteristics such as age and AXL. The degree and/or direction of associations varied between deep ONH structures and BMO-MRW or pRNFLT. Despite both BMO-MRW and pRNFLT being surrogate parameters for RGC loss, a complex relationship with ONH deep-layer morphology was indicated.

How is eyeball growth associated with optic nerve head shape and glaucoma? The Lamina cribrosa/Bruch's membrane opening offset theory

The optic nerve head (ONH) is a complex structure wherein the axons of the retinal ganglion cells extrude from the eyeball through three openings: 1) the Bruch's membrane opening (BMO) in the retinal layer, 2) the anterior scleral canal opening in the anterior scleral layer, and 3) the lamina cribrosa (LC). Eyeball expansion during growth induces an offset among openings, since the expansion affects the inner retinal and outer scleral layers differently: the posterior polar retinal structure is preserved by the preferential growth in the equatorial region, whereas no such regional difference is observed in the scleral layer. The various modes and extents of eyeball expansion result in diverse directionality and amount of offset among openings, which causes diverse ONH morphology in adults, especially in myopia. In this review, we summarize the ONH changes that occur during myopic axial elongation. These changes were observed prospectively in our previous studies, wherein LC shift and subsequent offset from the BMO center could be predicted by tracing the central retinal vascular trunk position. This offset induces the formation of γ-zone parapapillary atrophy or externally oblique border tissue. As a presumptive site of glaucomatous damage, the LC/BMO offset may render the LC pores in the opposite direction more vulnerable. To support such speculation, we also summarize the relationship between LC/BMO offset and glaucomatous damage. Indeed, LC/BMO offset is not only the cause of diverse ONH morphology in adults, but is also, potentially, an important clinical marker for assessment of glaucoma.

Peripapillary RNFL cross-sectional area and its association with other parameters in a Chinese population

BACKGROUND

Quantitative analysis of retinal nerve fibers is important for the diagnosis and treatment of optic nerve diseases. Peripapillary retinal nerve fiber layer (RNFL) cross-sectional area may give a more accurate quantitative assessment of retinal nerve fibers than RNFL thickness but there have been no previous reports of the peripapillary RNFL cross-sectional area or other parameters. The purpose of the current study was to determine peripapillary RNFL cross-sectional area and its association with other factors in an adult Chinese population.

METHODS

RNFL cross-sectional area was measured during peripapillary circular optical coherence tomography (OCT) scan with a diameter of 12° centered on the optic disc. Correlation between RNFL cross-sectional area and other parameters was evaluated by linear regression analysis in a cross-sectional study of an adult Chinese population.

RESULTS

A total of 2404 eyes from 2404 subjects were examined. Multivariate linear regression analysis showed that larger RNFL cross-sectional area correlated with younger age (p < 0.001), female gender (p = 0.001), no history of diabetes (p = 0.012) and larger optic disc area (p < 0.001).

CONCLUSIONS

Peripapillary RNFL cross-sectional area is correlated positively with optic disc area, suggesting that eyes with larger optic discs have thicker RNFL. Further studies are needed to confirm whether this correlation is due to differences in the numbers of retinal nerve fibers or other factors.

Peripapillary fluid: Obvious and not so obvious!

Intraretinal or subretinal fluid in the peripapillary area can be clinically visualized in conditions such as peripapillary choroidal neovascularization, optic disc pit maculopathy, and optic nerve head tumors and granulomas. Optical coherence tomography (OCT) helps to visualize peripapillary fluid in many other chorioretinal conditions such as peripapillary pachychoroid syndrome, posterior uveitis, central retinal vein occlusion, malignant hypertension, hypotonic maculopathy as well as neuro-ophthalmological conditions such as glaucoma, microcystic macular edema and disc edema due papilledema, non-arteritic anterior ischemic optic neuropathy, neuroretinitis, and diabetic papillopathy. Often, the differential diagnosis of peripapillary fluid is a bit tricky and may lead to misdiagnosis and improper management. We describe a diagnostic algorithm for peripapillary fluid on OCT and outline the salient features and management of these conditions.

OCT Optic Nerve Head Morphology in Myopia IV: Neural Canal Scleral Flange Remodeling in Highly Myopic Eyes

PURPOSE

To compare the prevalence, location and magnitude of optic nerve head (ONH) OCT-detected, exposed neural canal (ENC), externally oblique choroidal border tissue (EOCBT) and exposed scleral flange (ESF) regions in 122 highly myopic (Hi-Myo) versus 362 nonhighly myopic healthy (Non-Hi-Myo-Healthy) eyes.

DESIGN

Cross-sectional study.

METHODS

After OCT radial B-scan, ONH imaging, Bruch's membrane opening (BMO), the anterior scleral canal opening (ASCO), and the scleral flange opening (SFO) were manually segmented in each B-scan and projected to BMO reference plane. The direction and magnitude of BMO/ASCO offset and BMO/SFO offset as well as the location and magnitude of ENC, EOCBT and ESF regions, perineural canal (pNC) retinal nerve fiber layer thickness (RNFLT) and pNC choroidal thickness (CT) were calculated within 30° sectors relative to the Foveal-BMO (FoBMO) axis. Hi-ESF eyes were defined to be those with an ESF region ≥100 µms in at least 1 sector.

RESULTS

Hi-Myo eyes more frequently demonstrated Hi-ESF regions (87/122) than Non-Hi-myo-Healthy eyes (73/362) and contained significantly larger ENC, EOCBT, and ESF regions (P < .001) which were greatest in magnitude and prevalence within the inferior-temporal FoBMO sectors where Hi-Myo pNC-RNFLT and pNCCT were thinnest. BMO/ASCO offset and the BMO/SFO offset were both significantly increased (P < .001) in the Hi-Myo eyes, with the latter demonstrating a greater increase.

CONCLUSIONS

ENC region tissue remodeling that includes the scleral flange is enhanced in Hi-Myo compared to Non-Hi-Myo-Healthy eyes. Longitudinal studies are necessary to determine whether the presence of an ENC region influences ONH susceptibility to aging and/or glaucoma.

Fundus Tessellation and Parapapillary Atrophy, as Ocular Characteristics of Spontaneously High Myopia in Macaques: The Non-Human Primates Eye Study

Purpose

This study aimed to evaluate the ocular characteristics associated with spontaneously high myopia in adult nonhuman primates (NHPs).

Methods

A total of 537 eyes of 277 macaques with an average age of 18.53 ± 3.01 years (range = 5-26 years), raised in a controlled environment, were included. We measured ocular parameters, including spherical equivalent (SE), axial length (AXL), and intraocular pressure. The 45-degree fundus images centered on the macula and the disc assessed the fundus tessellation and parapapillary atrophy (PPA). Additionally, optical coherence tomography (OCT) was used to measure the thickness of the retinal nerve fiber layer (RNFL).

Results

The mean SE was -1.58 ± 3.71 diopters (D). The mean AXL was 18.76 ± 0.86 mm. The prevalence rate of high myopia was 17.7%. As myopia aggravated, the AXL increased (r = -0.498, P < 0.001). Compared with non-high myopia, highly myopic eyes had a greater AXL (P < 0.001), less RNFL thickness (P = 0.004), a higher incidence of PPA (P < 0.001), and elevated grades of fundus tessellation (P < 0.001). The binary logistic regression was performed, which showed PPA (odds ratio [OR] = 4.924, 95% confidence interval [CI] = 2.375-10.207, P < 0.001) and higher grades of fundus tessellation (OR = 1.865, 95% CI = 1.474-2.361, P < 0.001) were independent risk characteristics for high myopia.

Conclusions

In NHPs, a higher grade of fundus tessellation and PPA were significant biomarkers of high myopia.

Translational Relevance

The study demonstrates adult NHPs raised in conditioned rooms have a similar prevalence and highly consistent fundus changes with human beings, which strengthens the foundation for utilizing macaques as an animal model in high myopic studies.

Optic Nerve Head Pulsatile Displacement in Open-Angle Glaucoma after Intraocular Pressure Reduction Measured by Optical Coherence Tomography: A Pilot Study

This study investigated the effect of intraocular pressure (IOP) reduction on pulsatile displacement within the optic nerve head (ONH) in primary open-angle glaucoma (POAG) patients with and without axial myopia. Forty-one POAG patients (19 without myopia, 9 with axial myopia and 13 glaucoma with no intervention) participated. Swept-source optical coherence tomography (OCT) videos of the ONH were obtained before and after IOP-lowering treatment (medical or surgical) achieving a minimum IOP drop of 3 mmHg. A demons registration-based algorithm measured local pulsatile displacement maps within the ONH. Results demonstrated a significant 14% decrease in pulsatile tissue displacement in the non-myopic glaucoma cohort after intervention (p = 0.03). However, glaucoma patients with axial myopia exhibited no statistically significant change. There were no significant changes in the pulsatile ONH deformation in the control group. These findings suggest a potential link between IOP reduction and reduced pulsatile displacement within the ONH in POAG patients without myopia, offering new insights into the disease's pathophysiology and warranting further investigation into underlying mechanisms and clinical implications.

Comparing the morphology of optic nerve head and lamina cribrosa in full-term and preterm school-aged children

OBJECTIVES

To evaluate the morphology of lamina cribrosa (LC) in preterm school-aged children.

METHODS

A study of 120 eyes from 120 patients, including 42 full-term children (control group), 41 preterm children without retinopathy of prematurity (ROP), 16 children with ROP treated with intravitreal bevacizumab (IVB), and 21 children with ROP treated with laser. Five parameters of LC were measured by optical coherence tomography, including Bruch's membrane opening (BMO) diameter, minimum rim width (MRW), LC depth, prelaminar tissue (PLT) thickness, and LC curvature index (LCCI).

RESULTS

The PLT thickness increased with age in full-term and preterm children (β = 30.1, P = 0.003 and β = 19.6, P < 0.001, respectively). LC depth and LCCI showed no differences between full-term and preterm children. Worse refractive errors in preterm children were associated with greater MRW and PLT thickness (β = -17.1, P = 0.001 and β = -5.7, P = 0.03, respectively). However, this relationship was not found in full-term children. Laser-treated children had greater MRW, PLT, temporal peripapillary retinal nerve fibre layer, and foveal thickness than full-term or other preterm children (all P < 0.05).

CONCLUSIONS

Prematurity and ROP treatment may have an impact on the structural development of the LC. Refractive status plays a vital role in the LC structure of preterm children. This highlights the refractive errors of preterm children at school age that merit greater attention.

Characteristics of beta parapapillary atrophy in primary angle-closure suspect

OBJECTIVE

To investigate the characteristics of beta parapapillary atrophy (β-PPA) in patients with primary angle-closure suspect (PACS).

METHODS AND ANALYSIS

In total, 215 and 259 eyes with PACS and non-PACS (NPACS), respectively, were enrolled in this observational, cross-sectional study. Stereoscopic fundus and optical coherence tomography images were used to characterise β-PPA; the former was also used to measure the major β-PPA parameters. Univariate and multiple logistic regression analyses were used to identify the factors correlated with the presence of β-PPA and with β-PPA parameters.

RESULTS

The β-PPA occurrence rates were 48.80% and 44.40% in the PACS and NPACS groups, respectively, with no significant difference between groups. Compared with that in the NPACS group, the β-PPA area was significantly larger (p=0.005) in the PACS group, but the angular extent and maximum radial length did not differ between groups (p=0.110 and 0.657, respectively) after adjusting for age and axial length. The presence of β-PPA was associated with older age (OR 1.057, 95% CI 1.028 to 1.088, p<0.001) and larger disc area (OR 1.716, 95% CI 1.170 to 2.517, p=0.006). A larger β-PPA area was associated with older age (p=0.014), greater vertical cup-to-disc ratio (p=0.028), larger disc area (p<0.001) and PACS diagnosis (p=0.035).

CONCLUSION

48.80% of participants with PACS had β-PPA, which is slightly larger than NPACS. The area of β-PPA was larger in PACS, while the angular extent and maximum radial length did not differ between groups.

Quantification of peripapillary nerve fibre elevation and its association with axial length, optic disc tilt, and parapapillary atrophy area in young, healthy eyes

BACKGROUND

Eyes with peripapillary nerve fibre elevation (pNFE) may have a gap between the optic nerve papillary margin on colour fundus photography and Bruch's membrane opening on cross-sectional optical coherence tomography (OCT). This study was conducted to evaluate the quantification of the height of pNFE in young healthy eyes and examine the relationship between pNFE height and axial length.

METHODS

A prospective, observational, cross-sectional study was performed involving 117 right eyes. All participants (mean age 25.8 years) underwent comprehensive ophthalmologic examination involving axial length, fundus photography, and peripapillary and optic disc OCT. pNFE height was defined as the distance between the retinal surface plane and the upper edge of the pNFE in optic disc cross-sectional OCT images. Optic disc tilt was evaluated using a sine curve on retinal nerve fibre layer B-scan images. Parapapillary atrophy (PPA) area in colour fundus images was calculated using ImageJ and corrected using Bennett's formula. We evaluated relationships between pNFE height, axial length, optic disc papillary tilt, and PPA area using Spearman's correlation analysis.

RESULTS

Sixty-five eyes had pNFE, with a mean pNFE height of 84.7 μm. pNFE height was significantly positively correlated with axial length (r = 0.32, p < 0.001), optic disc tilt (r = 0.25, p = 0.008), and PPA area (r = 0.27, p = 0.004).

CONCLUSIONS

pNFE is not rare in young healthy eyes. Eyes with higher pNFE had a longer axial length and larger optic disc tilt and PPA area.

Targeting mechanics-induced trabecular meshwork dysfunction through YAP-TGFβ Ameliorates high myopia-induced ocular hypertension

High myopia is a risk factor for primary open angle glaucoma (POAG). The pathological mechanism of high myopia induced POAG occurrence is not fully understood. In this study, we successfully established the guinea pig model of ocular hypertension with high myopia, and demonstrated the susceptibility of high myopia for the occurrence of microbead-induced glaucoma compared with non-myopia group and the effect of YAP/TGF-β signaling pathway in TM pathogenesis induced by high myopia. Moreover, we performed stretching treatment on primary trabecular meshwork (TM) cells to simulate the mechanical environment of high myopia. It was found that stretching treatment disrupted the cytoskeleton, decreased phagocytic function, enhanced ECM remodeling, and promoted cell apoptosis. The experiments of mechanics-induced human TM cell lines appeared the similar trend. Mechanically, the differential expressed genes of TM cells caused by stretch treatment enriched YAP/TGF-β signaling pathway. To inhibit YAP/TGF-β signaling pathway effectively reversed mechanics-induced TM damage. Together, this study enriches mechanistic insights of high myopia induced POAG susceptibility and provides a potential target for the prevention of POAG with high myopia.

Association of macular outward scleral height with axial length, macular choroidal thickness and morphologic characteristics of the optic disc in Chinese adults

PURPOSE

To identify the relationship of macular outward scleral height (MOSH) with axial length (AL), macular choroidal thickness (ChT), peripapillary atrophy (PPA), and optic disc tilt in Chinese adults.

METHODS

In this cross-sectional study, 1088 right eyes of 1088 participants were enrolled and assigned into high myopia (HM) and non-HM groups. MOSH was measured in the nasal, temporal, superior, and inferior directions using swept-source optical coherence tomography images. The clinical characteristics of MOSH and the association of MOSH with AL, macular ChT, PPA, and tilt ratio were analysed.

RESULTS

The mean age of participants was 37.31 ± 18.93 years (range, 18-86 years), and the mean AL was 25.78 ± 1.79 mm (range, 21.25-33.09 mm). MOSH was the highest in the temporal direction, followed by the superior, nasal, and inferior directions (all p < 0.001). The MOSH of HM eyes was significantly higher than that of non-HM eyes, and it was positively correlated with AL in the nasal, temporal, and superior directions (all p < 0.001). Macular ChT was independently associated with the average MOSH (B = -0.190, p < 0.001). Nasal MOSH was positively associated with the PPA area and the presence of a tilted optic disc (both p < 0.01). Eyes with a higher MOSH in the superior (odds ratio [OR] = 1.008; p < 0.001) and inferior directions (OR = 1.006; p = 0.009) were more likely to have posterior staphyloma.

CONCLUSION

MOSH is an early indicator of scleral deformation, and it is correlated positively with AL and negatively with ChT. A higher nasal MOSH is associated with a larger PPA area and the presence of a tilted optic disc. Higher MOSH values in the superior and inferior directions were risk factors for posterior staphyloma.

CLINICAL TRIAL REGISTRATION

The study was registered at www.

CLINICALTRIALS

gov (Reg. No. NCT03446300).

Morphological differences of the neuroretinal rim between temporally tilted and non-tilted optic discs in healthy eyes

This study aimed to compare morphological differences of the neuroretinal rim between the temporally tilted and non-tilted optic discs in healthy eyes. We prospectively enrolled participants aged 20-40 years with temporally tilted or non-tilted optic discs. The optic nerve head parameters were analyzed using spectral domain-optical coherence tomography. The angle between the Bruch's membrane opening (BMO) plane and BMO-minimum rim width (BMO-MRW) was termed "BMO-MRW angle". Peripapillary retinal nerve fiber layer thickness (pRNFLT) and BMO-based parameters were compared between the temporally tilted and non-tilted disc groups. As a result, 55 temporally tilted disc eyes and 38 non-tilted disc eyes were analyzed. Global pRNFLT, global BMO-MRW, and total BMO-minimum rim area (BMO-MRA) were similar between the two groups (p = 0.138, 0.161, and p = 0.410, respectively). In the sectoral analysis, temporally tilted disc group exhibited thicker BMO-MRW in the temporal sector (p = 0.032) and thinner in the nasal superior and nasal sectors (p = 0.025 and p = 0.002, respectively). Temporally tilted disc group showed larger BMO-MRA in the temporal, temporal superior, and temporal inferior sectors (p < 0.001, p < 0.001, and p < 0.016, respectively), alongside a higher BMO-MRW angle in the temporal sector and lower in the nasal superior and nasal sectors. In conclusion, the neuroretinal rim, represented by BMO-MRW and BMO-MRA, showed morphological differences between temporally tilted and non-tilted optic discs in healthy eyes. BMO-MRW and BMO-MRA showed temporalization in the same manner as pRNFLT in the temporally tilted disc eyes. The BMO-MRW angle showed that in temporally tilted disc eyes, optic nerve fibers met the BMO plane steeply in the nasal sector and gently in the temporal sector than in non-tilted disc eyes, suggesting potential stress region of optic nerve fibers in temporally tilted disc eyes.

Drusen in the macula and parapapillary region

PURPOSE

To examine histological characteristics and differences between drusen beneath the retinal pigment epithelium (small hard drusen) located in the macula and located in the parapapillary region.

METHODS

We histomorphometrically examined human eyes enucleated due to uveal melanomas or secondary angle-closure glaucoma.

RESULTS

The study included 106 eyes (age, 62.6 ± 15.2 years) with macular drusen (n = 7 globes) or parapapillary drusen (n = 29 eyes) and 70 eyes without drusen. In all drusen, periodic-acid-Schiff-positive material was located between the RPE basal membrane and the inner collagenous layer of Bruch's membrane (BM). Macular drusen as compared with parapapillary drusen had lower height (15.2 ± 10.1 µm versus 34.3 ± 19.8 µm; P = 0.003), while both groups did not differ significantly in basal drusen width (74.0 ± 36.3 µm versus 108.7 ± 101.0 µm; P = 0.95). Eyes with macular drusen and eyes without drusen did not differ significantly in BM thickness (2.74 ± 0.44 µm versus 2.55 ± 0.88 µm; P = 0.57) or in RPE cell density (35.4 ± 10.4 cells/480 µm versus 32.8 ± 7.5 cells/480 µm; P = 0.53), neither in the drusen region nor in the drusen vicinity, while BM thickness (4.60 ± 1.490 µm; P < 0.001) and RPE cell density (56.9 ± 26.8 cells/480 µm; P = 0.005) were higher at the parapapillary drusen. Eyes with macular drusen, eyes with parapapillary drusen, and eyes without drusen did not differ significantly in choriocapillaris density (all P > 0.10) and thickness (all P > 0.35). Limitations of the study, among others, were a small number and size of drusen examined, diseases leading to enucleation, lack of serial sections, limited resolution of light microscopy, and enucleation-related and histological preparation-associated artefacts.

CONCLUSIONS

The findings of this study, also taking into account its methodological limitations, suggest that macular drusen and parapapillary drusen shared the morphological feature of periodic-acid-Schiff-positive material between the RPE basal membrane and BM and that they did not vary significantly in choriocapillaris thickness and density. RPE cell density and BM thickness were higher in parapapillary drusen than in macular drusen.

3D printed fibroblast-loaded hydrogel for scleral remodeling to prevent the progression of myopia

Pathologic myopia has seriously jeopardized the visual health of adolescents in the past decades. The progression of high myopia is associated with a decrease in collagen aggregation and thinning of the sclera, which ultimately leads to longer eye axis length and image formation in front of the retina. Herein, we report a fibroblast-loaded hydrogel as a posterior scleral reinforcement (PSR) surgery implant for the prevention of myopia progression. The fibroblast-loaded gelatin methacrylate (GelMA)-poly(ethylene glycol) diacrylate (PEGDA) hydrogel was prepared through bioprinting with digital light processing (DLP). The introduction of the PEGDA component endowed the GelMA-PEGDA hydrogel with a high compression modulus for PRS surgery. The encapsulated fibroblasts could consistently maintain a high survival rate during 7 days of in vitro incubation, and could normally secrete collagen type I. Eventually, both the hydrogel and fibroblast-loaded hydrogel demonstrated an effective shortening of the myopic eye axis length in a guinea pig model of visual deprivation over three weeks after implantation, and the sclera thickness of myopic guinea pigs became significantly thicker after 4 weeks, verifying the success of sclera remodeling and showing that myopic progression was effectively controlled. In particular, the fibroblast-loaded hydrogel demonstrated the best therapeutic effect through the synergistic effect of cell therapy and PSR surgery.

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.

Central visual field damage in glaucoma eyes with choroidal microvasculature dropout with and without high axial myopia

PURPOSE

To characterise the relationship between a deep-layer microvasculature dropout (MvD) and central visual field (VF) damage in primary open-angle glaucoma (POAG) patients with and without high axial myopia.

DESIGN

Cross-sectional study.

METHODS

Seventy-one eyes (49 patients) with high axial myopia and POAG and 125 non-highly myopic POAG eyes (97 patients) were enrolled. Presence, area and angular circumference of juxtapapillary MvD were evaluated on optical coherence tomography angiography B-scans and en-face choroidal images.

RESULTS

Juxtapapillary MvD was detected more often in the highly myopic POAG eyes (43 eyes, 86%) than in the non-highly myopic eyes (73 eyes, 61.9%; p=0.002). In eyes with MvD, MvD area and angular circumference (95% CI) were significantly larger in the highly myopic eyes compared with the non-highly myopic eyes (area: (0.69 (0.40, 0.98) mm2 vs 0.31 (0.19, 0.42) mm2, p=0.011) and (angular circumference: 84.3 (62.9, 105.8) vs 74.5 (58.3, 90.9) degrees, p<0.001), respectively. 24-2 VF mean deviation (MD) was significantly worse in eyes with MvD compared with eyes without MvD in both groups (p<0.001). After adjusting for 24-2 MD VF, central VF defects were more frequently found in eyes with MvD compared with eyes without MvD (82.7% vs 60.9%, p<0.001). In multivariable analysis, higher intraocular pressure, worse 24-2 VF MD, longer axial length and greater MvD area and angular circumference were associated with worse 10-2 VF MD.

CONCLUSIONS

MvD was more prevalent and larger in POAG eyes with high myopia than in non-highly myopic POAG eyes. In both groups, eyes with MvD showed worse glaucoma severity and more central VF defects.

A two-year longitudinal observational study of the peripapillary microvasculature in pediatric type 1 diabetes mellitus patients without visual impairment or diabetic retinopathy

•Neurodegeneration precede microcirculatory deterioration in DR. Early signs can be seen in DM patients without visible DR symptoms, such as glial cell apoptosis and thinner retinal nerve fiber layer.•Peripapillary microvascular abnormalities in the peripapillary region may affect the normal metabolism of neurons and eventually aggravate the process of DR.•Prompting ongoing research to monitor the peripapillary microcirculation and microvasculature among T1DM children for early detection and prevention.•In longitudinal observation, the vessel density of the peripapillary superficial capillary plexus were slightly affected, while vessel density, blood flow, vessel morphological abnormalities and flow impairment area were significantly deteriorated in the deep capillary plexus.•The peripapillary deep capillary plexus is more susceptible and vulnerable to DR progression and could be used as a target for DR screening.

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.

Optical Coherence Tomographic Optic Nerve Head Morphology in Myopia III: The Exposed Neural Canal Region in Healthy Eyes-Implications for High Myopia

PURPOSE

To determine the prevalence and magnitude of optical coherence tomography (OCT) exposed neural canal (ENC), externally oblique choroidal border tissue (EOCBT), and exposed scleral flange (ESF) regions in 362 non-highly myopic (spherical equivalent -6.00 to 5.75 diopters) eyes of 362 healthy subjects.

DESIGN

Cross-sectional study.

METHODS

After OCT optic nerve head (ONH) imaging, Bruch membrane opening (BMO), the anterior scleral canal opening (ASCO), and the scleral flange opening (SFO) were manually segmented. BMO, ASCO, and SFO points were projected to the BMO reference plane. The direction and magnitude of BMO/ASCO offset as well as the magnitude of ENC, EOCBT, and ESF was calculated within 30° sectors relative to the foveal-BMO axis. Hi-ESF eyes demonstrated an ESF ≥100 µm in at least 1 sector. Sectoral peri-neural canal choroidal thickness (pNC-CT) was measured and correlations between the magnitude of sectoral ESF and proportional pNC-CT were assessed.

RESULTS

Seventy-three Hi-ESF (20.2%) and 289 non-Hi-ESF eyes (79.8%) were identified. BMO/ASCO offset as well as ENC, EOCBT, and ESF prevalence and magnitude were greatest inferior temporally where the pNC-CT was thinnest. Among Hi-ESF eyes, the magnitude of each ENC region correlated with the BMO/ASCO offset magnitude, and the sectors with the longest ESF correlated with the sectors with proportionally thinnest pNC-CT.

CONCLUSIONS

ONH BMO/ASCO offset, either as a cause or result of ONH neural canal remodeling, corresponds with the sectoral location of maximum ESF and minimum pNC-CT in non-highly myopic eyes. Longitudinal studies to characterize the development and clinical implications of ENC Hi-ESF regions in non-highly myopic and highly myopic eyes are indicated.

Automatic Detection and Classification of Hypertensive Retinopathy with Improved Convolution Neural Network and Improved SVM

Hypertensive retinopathy (HR) results from the microvascular retinal changes triggered by hypertension, which is the most common leading cause of preventable blindness worldwide. Therefore, it is necessary to develop an automated system for HR detection and evaluation using retinal images. We aimed to propose an automated approach to identify and categorize the various degrees of HR severity. A new network called the spatial convolution module (SCM) combines cross-channel and spatial information, and the convolution operations extract helpful features. The present model is evaluated using publicly accessible datasets ODIR, INSPIREVR, and VICAVR. We applied the augmentation to artificially increase the dataset of 1200 fundus images. The different HR severity levels of normal, mild, moderate, severe, and malignant are finally classified with the reduced time when compared to the existing models because in the proposed model, convolutional layers run only once on the input fundus images, which leads to a speedup and reduces the processing time in detecting the abnormalities in the vascular structure. According to the findings, the improved SVM had the highest detection and classification accuracy rate in the vessel classification with an accuracy of 98.99% and completed the task in 160.4 s. The ten-fold classification achieved the highest accuracy of 98.99%, i.e., 0.27 higher than the five-fold classification accuracy and the improved KNN classifier achieved an accuracy of 98.72%. When computation efficiency is a priority, the proposed model's ability to quickly recognize different HR severity levels is significant.

Analysis of the relationship between axial length, optic disc morphology, and regional variations in retinal vessel density in young adults with healthy eyes

Purpose

To investigate the relationship between optic disc morphology, axial length, and regional distribution of retinal vessels in healthy eyes of young adults.

Methods

Nine hundred and two healthy eyes were enrolled in this university-based, cross-sectional study. Spectral-domain optical coherence tomography angiography was used to measure the parapapillary retinal vessel density. We automated the process of calculating optic disc tilt and rotation by using a program written in Python. Relationships between optic disc rotation, optic disc tilt, parapapillary vessel density, and other ocular parameters were analyzed using regression models.

Results

As axial length increased, optic disc morphology became more tilted and rotated inferiorly. The superficial vessel density (SVD) and radial peripapillary capillary density (RPCD) gradually decreased in all regions except for the temporal quadrant. Increased temporal SVD (OR [95% CI] = 1.081 [1.039, 1.124], p < 0.001), reduced nasal SVD (OR [95% CI] = 0.898 [0.861, 0.937], p < 0.01), and short relative lens position (OR [95% CI] = 0.126 [0.032, 0.495], p = 0.003) were significantly associated with the presence of a tilted optic disc. Inferior disc rotation was associated with decreased superior deep vessel density (DVD) and increased inferior DVD and temporal DVD after adjusting for sex and axial length.

Conclusion

The tilted and rotated optic discs were associated with the distribution of SVD and DVD, respectively. We should fully consider the influence of optic disc morphology on parapapillary vessel density in eyes with myopia.

Features of Peripapillary Hyperreflective Ovoid Mass-Like Structures in Nonarteritic Anterior Ischemic Optic Neuropathy Patients and Normal Controls

Purpose

To determine the characteristics of peripapillary hyperreflective ovoid mass-like structures (PHOMS) in patients with nonarteritic anterior ischemic optic neuropathy (NAION) and in normal adults.

Methods

A total of 406 included eyes were divided into four groups: acute NAION group, chronic NAION group, unaffected group, and normal eyes group. PHOMS were detected on optical coherence tomography slices from optical coherence tomography angiography scans centered on the optic nerve head (ONH). The differences in age, sex, and ONH parameters were investigated between eyes with PHOMS and eyes without PHOMS among groups.

Results

The prevalence of PHOMS in acute eyes (43.48%) and fellow eyes (28.20%) was significantly higher than that in normal eyes (11.76%) (acute vs. normal, P < 0.001; fellow vs. normal, P = 0.014). In the acute group, the PHOMS score of size was negatively correlated with age in acute eyes (r = -0.486, P = 0.03). The size of PHOMS was negatively correlated with age and cup/disc ratio and positively correlated with retinal nerve fiber layer thickness in the nasal and inferior sectors in the normal groups. No differences in age, sex, ONH parameters, or visual field defects were found between eyes with PHOMS and eyes without PHOMS.

Conclusions

The prevalence of PHOMS increased significantly in acute nonoptic disc drusen (NODD)-NAION eyes and fellow eyes. PHOMS could also be found among normal adults. PHOMS may be a nonspecific sign secondary to ONH edema and axoplasmic stasis.

Translational Relevance

The high prevalence of PHOMS in acute NODD-NAION eyes may indicate axoplasmic stasis secondary to tissue edema.

Relationship of Choroidal Microvasculature Dropout and Beta Zone Parapapillary Area With Visual Field Changes in Glaucoma

PURPOSE

To evaluate the association between rates of choroidal microvasculature dropout (MvD) change, beta zone parapapillary atrophy (β-PPA) area change, and visual field (VF) changes in eyes with primary open-angle glaucoma (POAG).

DESIGN

Retrospective, observational cohort study.

METHODS

In a tertiary glaucoma clinic, we included 76 eyes from 58 patients with POAG with and without localized MvD, who had ≥2 years of follow-up with a minimum of 4 visits with optical coherence tomography angiography and optical coherence tomography scans. β-PPA area was evaluated using scanning laser ophthalmoscopy-like images and compared with the area of MvD on an en face choroidal vessel density map during the follow-up period. Joint longitudinal mixed effects models were used to estimate the rates of change in β-PPA area or MvD area and VF mean deviation (MD).

RESULTS

Mean rates of change in β-PPA and MvD area were 0.037 mm2 (95% confidence interval [CI] 0.030-0.043 mm2) per year and 0.039 mm2 (95% CI 0.029-0.048 mm2) per year, respectively, over the mean follow-up of 4.1 years. In multivariable models, MvD area enlargement was significantly associated with faster rates of VF MD loss (0.03 mm2 [95% CI 0.02-0.04 mm2] per 1-dB worse, P < .001) but not β-PPA area enlargement (0.04 mm2 [95% CI 0.03-0.05 mm2] per 1-dB worse, P = .252).

CONCLUSION

MvD area rates, but not β-PPA area rates, were associated with VF MD loss changes in eyes with POAG. Assessment of MvD is useful for the detection of patients with glaucoma who are at an increased risk of faster VF loss.

Computational study on the effects of central retinal blood vessels with asymmetric geometries on optic nerve head biomechanics

Optic nerve head (ONH) biomechanics are associated with glaucoma progression and have received considerable attention. Central retinal vessels (CRVs) oriented asymmetrically in the ONH are the single blood supply source to the retina and are believed to act as mechanically stable elements in the ONH in response to intraocular pressure (IOP). However, these mechanical effects are considered negligible in ONH biomechanical studies and received less attention. This study investigated the effects of CRVs on ONH biomechanics taking into consideration three-dimensional asymmetric CRV geometries. A CRV geometry was constructed based on CRV centerlines extracted from optical coherence tomography ONH images in eight healthy subjects and superimposed in the idealized ONH geometry established in previous studies. Mechanical analyses of the ONH in response to the IOP were conducted in the cases with and without CRVs for comparison. Obtained results demonstrated that the CRVs induced anisotropic ONH deformation, particularly in the lamina cribrosa and the associated upper neural tissues (prelamina) with wide ranges of spatial strain distributions. These results indicated that the CRVs result in anisotropic deformation with local strain concentration, rather than function to mechanically support in response to the IOP as in the conventional thinking in ophthalmology.

Topical Atropine for Childhood Myopia Control: The Atropine Treatment Long-Term Assessment Study

Importance

Clinical trial results of topical atropine eye drops for childhood myopia control have shown inconsistent outcomes across short-term studies, with little long-term safety or other outcomes reported.

Objective

To report the long-term safety and outcomes of topical atropine for childhood myopia control.

Design, Setting, and Participants

This prospective, double-masked observational study of the Atropine for the Treatment of Myopia (ATOM) 1 and ATOM2 randomized clinical trials took place at 2 single centers and included adults reviewed in 2021 through 2022 from the ATOM1 study (atropine 1% vs placebo; 1999 through 2003) and the ATOM2 study (atropine 0.01% vs 0.1% vs 0.5%; 2006 through 2012).

Main Outcome Measures

Change in cycloplegic spherical equivalent (SE) with axial length (AL); incidence of ocular complications.

Results

Among the original 400 participants in each original cohort, the study team evaluated 71 of 400 ATOM1 adult participants (17.8% of original cohort; study age, mean [SD] 30.5 [1.2] years; 40.6% female) and 158 of 400 ATOM2 adult participants (39.5% of original cohort; study age, mean [SD], 24.5 [1.5] years; 42.9% female) whose baseline characteristics (SE and AL) were representative of the original cohort. In this study, evaluating ATOM1 participants, the mean (SD) SE and AL were -5.20 (2.46) diopters (D), 25.87 (1.23) mm and -6.00 (1.63) D, 25.90 (1.21) mm in the 1% atropine-treated and placebo groups, respectively (difference of SE, 0.80 D; 95% CI, -0.25 to 1.85 D; P = .13; difference of AL, -0.03 mm; 95% CI, -0.65 to 0.58 mm; P = .92). In ATOM2 participants, the mean (SD) SE and AL was -6.40 (2.21) D; 26.25 (1.34) mm; -6.81 (1.92) D, 26.28 (0.99) mm; and -7.19 (2.87) D, 26.31 (1.31) mm in the 0.01%, 0.1%, and 0.5% atropine groups, respectively. There was no difference in the 20-year incidence of cataract/lens opacities, myopic macular degeneration, or parapapillary atrophy (β/γ zone) comparing the 1% atropine-treated group vs the placebo group.

Conclusions and Relevance

Among approximately one-quarter of the original participants, use of short-term topical atropine eye drops ranging from 0.01% to 1.0% for a duration of 2 to 4 years during childhood was not associated with differences in final refractive errors 10 to 20 years after treatment. There was no increased incidence of treatment or myopia-related ocular complications in the 1% atropine-treated group vs the placebo group. These findings may affect the design of future clinical trials, as further studies are required to investigate the duration and concentration of atropine for childhood myopia control.

Prevalence and Cause of Loss of Visual Acuity and Visual Field in Highly Myopic Eyes: The Beijing Eye Study

PURPOSE

To explore the prevalence and causes of loss of visual acuity and visual field in highly myopic eyes.

DESIGN

Population-based study.

PARTICIPANTS

4439 subjects of the Beijing Eye Study underwent ophthalmological and systemic examinations including frequency doubling technology perimetry.

METHODS

High myopia was defined by a refractive error of ≤-6 diopters (D) or axial length >26.0 mm.

MAIN OUTCOME MEASURES

Prevalence of vision impairment causes.

RESULTS

212 highly myopic eyes from 154 participants were included with a mean age of 56.2 ± 9.6 years, a mean refractive error of -9.87 ± 3.70 D and a mean axial length of 27.2 ± 1.3 mm. We observed moderate/severe vision impairment (MSVI) in 40 eyes (18.9%; 95% confidence interval [CI], 13.6-24.2) and blindness in 10 eyes (4.7%; 95% CI, 1.8-7.6). Primary causes for MSVI and blindness were myopic macular degeneration (MMD) (29/50; 58%), age-related macular degeneration (1/50; 2%), and branch macular retinal vein occlusion (1/50; 2%). Secondary causes were MMD (4/50; 8%) and optic nerve atrophy (14/50, 28%), further differentiated into non-glaucomatous optic atrophy (NGOA) (9/50; 18%) and glaucomatous optic atrophy (GOA) (5/50; 10%). Prevalence of MMD as vision impairment cause increased significantly from 1/61 (1.6%) in the refractive error group of -6.00 to ≥-7.00 D, to 16/25 (64%) in the group of <-15.0 D. Higher MMD prevalence correlated with higher myopic refractive error (P < 0.001) and increased likelihood of concomitant optic neuropathy (P < 0.001). Similarly, prevalence of optic neuropathy as vision impairment cause increased from 0/61 (0%) in the refractive error group of -6.00 D to ≥-7.00 D, to 9/25 (36%) in the group of <-15.0 D. Higher optic neuropathy prevalence correlated with more myopic refraction (P < 0.001) and older age (P = 0.02).

CONCLUSIONS

In this population-based recruited cohort of highly myopic patients, optic neuropathy accounted for vision impairment in 9.0% eyes, which was lower than the prevalence of MMD as vision impairment cause (18.9%). Notably, optic neuropathy became a significant contributor to vision impairment in more advanced high myopia, reaching 36% in the group with refractive error of <-15.0 D.

FINANCIAL DISCLOSURE(S)

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

External validation of a deep learning detection system for glaucomatous optic neuropathy: a real-world multicentre study

OBJECTIVES

To conduct an external validation of an automated artificial intelligence (AI) diagnostic system using fundus photographs from a real-life multicentre cohort.

METHODS

We designed external validation in multiple scenarios, consisting of 3049 images from Qilu Hospital of Shandong University in China (QHSDU, validation dataset 1), 7495 images from three other hospitals in China (validation dataset 2), and 516 images from high myopia (HM) population of QHSDU (validation dataset 3). The corresponding sensitivity, specificity and accuracy of this AI diagnostic system to identify glaucomatous optic neuropathy (GON) were calculated.

RESULTS

In validation datasets 1 and 2, the algorithm yielded accuracy of 93.18% and 91.40%, area under the receiver operating curves (AUC) of 95.17% and 96.64%, and significantly higher sensitivity of 91.75% and 91.41%, respectively, compared to manual graders. On the subsets complicated with retinal comorbidities, such as diabetic retinopathy or age-related macular degeneration, in validation datasets 1 and 2, the algorithm achieved accuracy of 87.54% and 93.81%, and AUC of 97.02% and 97.46%, respectively. In validation dataset 3, the algorithm achieved comparable accuracy of 81.98% and AUC of 87.49%, with a sensitivity of 83.61% and specificity of 81.76% on GON recognition specifically in the HM population.

CONCLUSIONS

With acceptable generalization capability across varying levels of image quality, different clinical centres, or certain retinal comorbidities, such as HM, the automatic AI diagnostic system had the potential to provide expert-level glaucoma detection.

Parapapillary βBM and γ Zones Played Different Roles in Axial Elongation Among Young Adolescents Using Optical Coherence Tomography

Purpose

To evaluate the influencing factors of parapapillary βBM and γ zones incidence in young adolescents and to explore their associations with axial length progression.

Methods

In this prospective cohort study, 976 seventh-grade students from nine secondary schools in Beijing, China, were enrolled and followed up 1 year later. Parapapillary βBM zone was defined as retinal pigment epithelium loss while Bruch's membrane was present. Parapapillary γ zone was defined as the absence of retinal pigment epithelium and Bruch's membrane. Logistic regression model was used to analyze the influencing factors of βBM and γ zone incidence. A linear mixed model was used to analyze the associations between parapapillary zones and axial elongation.

Results

Of the 976 participants, 139 (14.2%) had only βBM zone, 398 (40.8%) had only γ zone, and 171 (17.5%) had both. At follow-up, the incidence of βBM zone was 11.5% (76/659), and the incidence of γ zone was 9.7% (39/404). Optic disc tilt, thinner subfoveal choroid, and longer axial length at baseline showed a higher risk of γ zone incidence. The absence of γ zone at baseline showed a faster axial length progression. When the baseline axial length was 25 mm or longer, the βBM zone was also related to the axial elongation.

Conclusions

The γ zone was associated with axial length progression, and the βBM zone was also associated with the axial length progression when the axial length exceeded 25 mm, which was consistent with the notion that excessive axial length growth not only is the extension of the eyeball but also has its own pathologic changes.

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.

Parapapillary gamma zone associated with increased peripapillary scleral bowing: the Beijing Eye Study 2011

AIMS

To investigate the association between the backward configuration of the peripapillary sclera (PPS), measured as PPS angle (PPSA), and presence and extent of parapapillary gamma zone.

METHODS

Out of the population-based Beijing Eye Study 2011, we randomly selected individuals free of optic nerve and retinal diseases. With Spectralis optical coherence tomography, we measured gamma zone (zone free of Bruch's membrane (BM)) and determined the PPSA, defined as the angle between the anterior scleral surface lines from both sides of the optic nerve head (ONH).

RESULTS

The study included 678 individuals with age of 59.5±7.6 years (range: 50-90) and axial length of 23.5±1.3 mm (20.9-29.2). Gamma zone was more prevalent in eyes with larger PPSA (p=0.006) after adjustment for axial length (p<0.001) and BM opening area (p<0.001). Gamma zone width was positively associated with PPSA, axial length and BM opening area (all p<0.001) in multivariable analysis. Circular gamma zone was accompanied with larger PPSA as compared with focal gamma zone (19.9°±7.2° vs 6.3°±5.3°, p<0.001). Focal temporal gamma and focal inferior gamma had similar mean PPSA (p=0.69). However, the horizontal PPSA was significantly larger than the vertical PPSA in inferior gamma (6.9°±6.3° vs 4.7°±6.6°; p=0.005), while they were comparable in temporal gamma (6.1°±5.8° vs 6.3°±6.4°; p=0.073).

CONCLUSIONS

A more backward bowing of the PPS was linearly and spatially associated with the presence, size and extent of gamma zone. It suggested that the BM and the sclera were closely related in participating the biomechanical behaviour of the ONH.

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.

Choriocapillaris and progressive ganglion cell-inner plexiform layer loss in non-glaucomatous eyes

AIMS

To explore the relationship between choriocapillaris (CC) flow deficit percentage (FD%) and ganglion cell-inner plexiform layer (GCIPL) thickness in a population-based sample of non-glaucomatous eyes.

METHODS

This is a longitudinal cohort study and prospective cross-sectional study. Non-glaucoma Chinese subjects aged 18 years or older were enrolled. All participants underwent a detailed ophthalmic examination, including swept-source optical coherence tomography (SS-OCT) and SS-OCT angiography. Average, inner average, outer average and nine Early Treatment Diabetic Retinopathy Study sub-regions of GCIPL thickness and CC FD% were measured. The correlation between CC FD% and GCIPL was assessed using a linear regression model, and the relationship between the rate of change of GCIPL thickness and CC FD% was further validated in a 2year longitudinal study.

RESULTS

In the cross-sectional study including 3514 participants (3514 non-glaucoma eyes), a higher CC FD% was significantly associated with a thinner GCIPL (β=-0.32; 95% CI -0.43 to -0.21; p<0.001). Further, in a longitudinal study (453 eyes of 453 participants), a faster increase in CC FD% was found to be significantly associated with a faster decrease in GCIPL thickness (β=-0.10; 95% CI -0.17 to -0.03; p=0.004) after adjusting for age, sex, axial length and image quality score.

CONCLUSIONS

This is the first time to show that CC FD% and GCIPL thickness were correlated in both cross-sectional and longitudinal studies of non-glaucomatous individuals, which may potentially provide further insights on the role of CC perfusion in glaucoma development and progression.

Optic Nerve Head Abnormalities in Nonpathologic High Myopia and the Relationship With Visual Field

PURPOSE

To describe the optic nerve head (ONH) abnormalities in nonpathologic highly myopic eyes based on swept-source optical coherence tomography (OCT) and the relationship with visual field (VF).

DESIGN

Secondary analysis from a longitudinal cohort study.

METHODS

Highly myopic patients without myopic maculopathy of category 2 or higher were enrolled. All participants underwent a swept-source OCT examination focused on ONH. We differentiated between 3 major types (optic disc morphologic abnormality, papillary/peripapillary tissue defect, and papillary/peripapillary schisis) and 12 subtypes of ONH abnormalities. The prevalence and characteristics of ONH abnormalities and the relationship with VF were analyzed.

RESULTS

A total of 857 participants (1389 eyes) were included. Among the 1389 eyes, 91.86%, 68.61%, and 34.92% of them had at least 1, 2, or 3 ONH abnormalities, respectively, which corresponded to 29.55%, 31.79%, and 35.67% of VF defects, respectively. Among the 12 subtypes of the 3 major types, peripapillary hyperreflective ovoid mass-like structure, visible retrobulbar subarachnoid space, and prelaminar schisis were the most common, respectively. Perimetric defects corresponding to OCT abnormalities were more commonly found in eyes with peripapillary retinal detachment, peripapillary retinoschisis, and peripapillary hyperreflective ovoid mass-like structure. Glaucoma-like VF defects were more common in eyes with deep optic cups (28.17%) and with optic disc pit/pit-like change (18.92%).

CONCLUSIONS

We observed and clarified the ONH structural abnormalities in eyes with nonpathologic high myopia. These descriptions may be helpful to differentiate changes in pathologic high myopia or glaucoma.

Choriocapillaris, Photoreceptors, and Inner Retinal Layer in Spatial Relationship to Parapapillary Alpha, Beta, Gamma, and Delta Zones

Purpose

To examine the spatial relationships between the retinal inner nuclear layer (INL), outer nuclear layer (ONL), retinal pigment epithelium (RPE) layer, Bruch's membrane (BM), and choriocapillaris in the parapapillary region.

Methods

Human eyes enucleated due to uveal melanomas or secondary angle-closure glaucoma were histomorphometrically examined. We compared the tissue dimensions between four groups of eyes categorized based on the presence/absence of high myopia and glaucoma.

Results

The investigation consisted of 100 globes (axial length: 25.6 ± 3.1 mm; range: 20.0-35.0 mm). In non-highly myopic nonglaucomatous eyes, the INL, ONL, RPE, BM, and choriocapillaris ended approximately at the end of the RPE layer, with no significant (all P ≥ 0.10) difference between the layers in their distance to the RPE-layer end. From non-highly myopic nonglaucomatous eyes to non-highly myopic glaucomatous eyes, highly myopic nonglaucomatous eyes, and eventually highly myopic glaucomatous eyes, the choriocapillaris, INL, and ONL increasingly extended into the beta zone, most marked for the choriocapillaris and least marked for the ONL. A larger extension of the choriocapillaris into the parapapillary beta zone correlated with longer axial length (standardized regression coefficient β, 0.24; B, 23.0; 95% confidence interval [CI], 1.6-44.5; P = 0.04) and wider parapapillary beta zone (β, 0.59; B, 0.32; 95% CI, 0.22-0.41; P < 0.001); a larger extension of the INL correlated with longer axial length (β, 0.34; B, 43.7; 95% CI, 11.6-75.7; P = 0.009), longer gamma zone (β, 0.52; B, 0.28; 95% CI, 0.15-0.41; P < 0.001), and diagnosis of non-highly myopic glaucoma (β, 0.28; B, 267; 95% CI, 80.8-454; P = 0.006); and a larger extension of the ONL into parapapillary beta zone correlated with longer axial length (β, 0.50; B, 32.2; 95% CI, 21.6-42.8; P < 0.001) and wider parapapillary beta zone (β, 0.28; B, 0.10; 95% CI, 0.04-0.16; P < 0.001).

Conclusions

Nonglaucomatous non-highly myopic eyes differ from highly myopic eyes and glaucomatous eyes in the spatial relationship of the parapapillary tissue layers.

Refractive Error Changes Due to COVID-19 Pandemic Confinement in Children from Puerto Rico: A Retrospective Study

SIGNIFICANCE

The progression of myopia increased in children after the pandemic confinement. A myopic shift in the refractive error of the Hispanic population was found regardless of the refractive status of the school-aged children studied.

PURPOSE

This study aimed to evaluate the refractive error in Puerto Rican children before and after the COVID-19 pandemic. We were interested in whether there was a significant change in refractive error attributed to online learning during the pandemic lockdown.

METHODS

A retrospective record review of children aged 7 to 18 years who underwent a comprehensive visual evaluation between 2018 and 2021 at the Inter American Eye Institute in Puerto Rico was performed. The spherical equivalent pre- and post-lockdown was compared. The study excluded the best-corrected visual acuities worse than 20/40, any corneal or retinal disease, and amblyopia.

RESULTS

In total, 801 records were included in this study. The mean age was 12.7 ± 3.2 years, with 50.3% male and 49.7% female children. The mean spherical equivalent for the right and left eyes was similar ( r = 0.93, P ≤ .001). A significant difference in the mean spherical equivalent was found pre- and post- lockdown (0.22 ± 0.59 D, t800 = 10.44, P ≤ .001). A myopic shift post-lockdown was significant for all ages except those in the 7- (0.13 ± 0.79 D, t28 = 0.84, P = .40) and 8-year-old range (0.12 ± 0.65 D, t40 = 1.22, P = .23), respectively. No significant change was found between sexes before (0.16 ± 0.12 D; t799 = 1.38, P = .16) and after (0.15 ± 0.13 D; t799 = 1.19, P = .23) confinement.

CONCLUSIONS

The current study revealed a significant myopic shift in Hispanic school-aged children as a result of the pandemic confinement.

OCT Optic Nerve Head Morphology in Myopia II: Peri-Neural Canal Scleral Bowing and Choroidal Thickness in High Myopia-An American Ophthalmological Society Thesis

PURPOSE

To use optical coherence tomography (OCT) to characterize optic nerve head (ONH) peri-neural canal (pNC) scleral bowing (pNC-SB) and pNC choroidal thickness (pNC-CT) in 69 highly myopic and 138 healthy, age-matched, control eyes.

DESIGN

Cross-sectional, case control study.

METHODS

Within ONH radial B-scans, Bruch membrane (BM), BM opening (BMO), anterior scleral canal opening (ASCO), and pNC scleral surface were segmented. BMO and ASCO planes and centroids were determined. pNC-SB was characterized within 30° foveal-BMO (FoBMO) sectors by 2 parameters: pNC-SB-scleral slope (pNC-SB-SS), measured within 3 pNC segments (0-300, 300-700, and 700-1000 μm from the ASCO centroid); and pNC-SB-ASCO depth relative to a pNC scleral reference plane (pNC-SB-ASCOD). pNC-CT was calculated as the minimum distance between the scleral surface and BM at 3 pNC locations (300, 700, and 1100 μm from the ASCO).

RESULTS

pNC-SB increased and pNC-CT decreased with axial length (P < .0133; P < .0001) and age (P < .0211; P < .0004) among all study eyes. pNC-SB was increased (P < .001) and pNC-CT was decreased (P < .0279) in the highly myopic compared to control eyes, and these differences were greatest in the inferior quadrant sectors (P < .0002). Sectoral pNC-SB was not related to sectoral pNC-CT in control eyes, but was inversely related to sectoral pNC-CT (P < .0001) in the highly myopic eyes.

CONCLUSIONS

Our data suggest that pNC-SB is increased and pNC-CT is decreased in highly myopic eyes and that these phenomena are greatest in the inferior sectors. They support the hypothesis that sectors of maximum pNC-SB may predict sectors of greatest susceptibility to aging and glaucoma in future longitudinal studies of highly myopic eyes. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Racial and Ethnic Differences in the Roles of Myopia and Ocular Biometrics as Risk Factors for Primary Open-Angle Glaucoma

Purpose

Assess how the roles of refractive error (RE) and ocular biometrics as risk factors for primary open-angle glaucoma (POAG) differ by race and ethnicity.

Methods

Data from the Los Angeles Latino Eye Study (LALES) and the Chinese American Eye Study (CHES), two population-based epidemiological studies, were retrospectively analyzed. Multivariable logistic regression and interaction term analyses were performed to assess relationships between POAG and its risk factors, including RE and axial length (AL), and to assess effect modification by race/ethnicity.

Results

Analysis included 7601 phakic participants of LALES (47.3%) and CHES (52.7%) with age ≥ 50 years. Mean age was 60.6 ± 8.3 years; 60.9% were female. The prevalence and unadjusted risk of POAG were higher in LALES than CHES (6.0% and 4.0%, respectively; odds ratio [OR] = 1.55; P < 0.001). In the multivariable analysis, significant risk factors for POAG included Latino ethnicity (OR = 2.25; P < 0.001), refractive myopia (OR = 1.54 for mild, OR = 2.47 for moderate, OR = 3.94 for high compared to non-myopes; P ≤ 0.003), and longer AL (OR = 1.37 per mm; P < 0.001). AL (standardized regression coefficient [SRC] = 0.3) was 2.7-fold more strongly associated with POAG than high myopia status (SRC = 0.11). There was no modifying effect by race/ethnicity on the association between RE (per diopter) or AL (per millimeter) and POAG (P = 0.49).

Conclusions

Although the POAG risk conferred by myopic RE and longer AL is similar between Latino and Chinese Americans, the difference in POAG prevalence between the two groups is narrowed by higher myopia prevalence among Chinese Americans. Racial/ethnic populations with higher myopia incidence may become disproportionately affected by POAG in the context of the global myopia epidemic.

Progress in clinical characteristics of high myopia with primary open-angle glaucoma

High myopia (HM) is a significant risk factor for the occurrence and progression of primary open-angle glaucoma (POAG). Identification with POAG in the HM population is an emergent challenge. Patients with HM have a significantly higher probability of complicating POAG than those without HM. When HM is associated with POAG, the changes to the fundus caused by both of them are confused with each other, making the diagnosis of early glaucoma difficult. This article reviews available researches on HM with POAG, summarizing the characteristics of the fundus structure such as epidemiology, intraocular pressure, optic disc, ganglion cell layer, retinal nerve fiber layer, vascular density, and visual field.

Graphene-based microfluidic perforated microelectrode arrays for retinal electrophysiological studies

Perforated microelectrode arrays (pMEAs) have become essential tools for ex vivo retinal electrophysiological studies. pMEAs increase the nutrient supply to the explant and alleviate the accentuated curvature of the retina, allowing for long-term culture and intimate contacts between the retina and electrodes for electrophysiological measurements. However, commercial pMEAs are not compatible with in situ high-resolution optical imaging and lack the capability of controlling the local microenvironment, which are highly desirable features for relating function to anatomy and probing physiological and pathological mechanisms in retina. Here we report on microfluidic pMEAs (μpMEAs) that combine transparent graphene electrodes and the capability of locally delivering chemical stimulation. We demonstrate the potential of μpMEAs by measuring the electrical response of ganglion cells to locally delivered high K+ stimulation under controlled microenvironments. Importantly, the capability for high-resolution confocal imaging of the retina tissue on top of the graphene electrodes allows for further analyses of the electrical signal source. The new capabilities provided by μpMEAs could allow for retinal electrophysiology assays to address key questions in retinal circuitry studies.

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.

Longitudinal Changes of Bruch's Membrane Opening, Anterior Scleral Canal Opening, and Border Tissue in Experimental Juvenile High Myopia

Purpose

To investigate the relative positional changes between the Bruch's membrane opening (BMO) and the anterior scleral canal opening (ASCO), and border tissue configuration changes during experimental high myopia development in juvenile tree shrews.

Methods

Juvenile tree shrews were assigned randomly to two groups: binocular normal vision (n = 9) and monocular -10 D lens treatment starting at 24 days of visual experience to induce high myopia in one eye while the other eye served as control (n = 12). Refractive and biometric measurements were obtained daily, and 48 radial optical coherence tomography B-scans through the center of the optic nerve head were obtained weekly for 6 weeks. ASCO and BMO were segmented manually after nonlinear distortion correction.

Results

Lens-treated eyes developed high degree of axial myopia (-9.76 ± 1.19 D), significantly different (P < 0.001) from normal (0.34 ± 0.97 D) and control eyes (0.39 ± 0.88 D). ASCO-BMO centroid offset gradually increased and became significantly larger in the experimental high myopia group compared with normal and control eyes (P < 0.0001) with an inferonasal directional preference. The border tissue showed a significantly higher tendency of change from internally to externally oblique configuration in the experimental high myopic eyes in four sectors: nasal, inferonasal, inferior, and inferotemporal (P < 0.005).

Conclusions

During experimental high myopia development, progressive relative deformations of ASCO and BMO occur simultaneously with changes in border tissue configuration from internally to externally oblique in sectors that are close to the posterior pole (nasal in tree shrews). These asymmetric changes may contribute to pathologic optic nerve head remodeling and an increased risk of glaucoma later in life.

[Post-SMILE-What myopes know about their secondary emmetropic eyes]

BACKGROUND

Small incision lenticule extraction (SMILE) is popular among young myopic adults for long-term correction of myopia; however, the excessive axial lengths of myopic eyes and the associated risks for more serious eye diseases later on remain with surgical correction of the refractive error. These risks are greater the higher the myopia is. Are patients well informed about this and to what extent does further eye growth occur even after SMILE?

MATERIAL AND METHODS

Myopic young adults who underwent binocular SMILE before 2019 were given the opportunity to have their eyes examined at a follow-up visit (biometry using IOL-Master 700 [Zeiss, Oberkochen, Germany], subjective refraction, examination of the anterior and posterior segments of the eye using the slit lamp) and to participate in a survey. Patients with a preoperative axial length ≥ 25.5 mm and a preoperative axial length < 25.5 mm (high myopia) were statistically evaluated separately.

RESULTS

A total of 44 patients (age 30.39 ± 2.39 years) appeared at the visit and the SMILE was 3.18 ± 0.82 years ago: The spherical equivalent at the follow-up visit was -0.05 ± 0.21 dpt in the weaker myopes and -0.18 ± 0.23 dpt in the high myopes. Of the respondents 27% estimated that SMILE would reduce the risk of retinal detachment and cataract, with 80% of high myopes underestimating the individual risk of retinal detachment. Also, 57% said they would not see an ophthalmologist until within 1 week if they had symptoms consistent with acute retinal detachment, and only 27% would go to an emergency room immediately. In general, 59% reported having normal health awareness and 41% reported going for annual ophthalmological check-ups.

CONCLUSION

The collected axial lengths and refractions show no relevant change in the eyes regarding progression of myopia; however, the patients' statements in the survey point out that most patients are not aware of the risk of serious eye diseases (retinal detachment, cataract). Therefore, repeated risk education and close postoperative care are needed, especially in preoperatively highly myopic patients.

Histology of the optic nerve head with special reference to the layer-specific distribution of composite fibers at and near the lamina cribrosa: An immunohistochemical study using specimens from elderly donated cadavers

BACKGROUND

This study aimed to demonstrate the composite fibers of the lamina cribrosa (LC) and their layer-specific distributions. The elastic fiber-rich septa, showing a cribriform arrangement in the optic nerve, may continue into the LC.

METHODS

Orbital content, including the long course of the optic nerve, was obtained from 25 elderly cadavers. Sagittal and cross-sections were prepared from each specimen. In addition to elastica Masson staining, immunohistochemistry was performed for elastin, glial fibrillary acidic protein (GFAP), S100 protein (S100), and CD68 in microglia.

RESULTS

The LC beam usually had fewer elastic fibers than the septa, but an elastic fiber-rich zone was observed along the scleral flange. GFAP-positive fibers were rich in the prelaminar area, whereas S100-positive fibers were rich in all layers of the LC. Double-positive (GFAP+/S100+) fibers were present in the prelaminar area. In contrast, S100-single positive fibers were evident in the LC and retrolaminar areas and were likely to insert into a sclera-choroid border area. The density of macrophages and microglia was not different between the septa and LC. Individual variations were observed in the distribution and density of the nerve-associated fibrous tissues.

CONCLUSION

The LC beam was quite different from the septa in the composite fibers and architecture. Transverse fibers, dominant in the LC beam, corresponded to fibrous processes of astrocytes and other nerve-associated fibrous tissues. Many of these nerve elements suggest low mechanical properties of the LC.

Update on the Utility of Optical Coherence Tomography in the Analysis of the Optic Nerve Head in Highly Myopic Eyes with and without Glaucoma

Glaucoma diagnosis in highly myopic subjects by optic nerve head (ONH) imaging is challenging as it is difficult to distinguish structural defects related to glaucoma from myopia-related defects in these subjects. Optical coherence tomography (OCT) has evolved to become a routine examination at present, providing key information in the assessment of glaucoma based on the study of the ONH. However, the correct segmentation and interpretation of the ONH data employing OCT is still a challenge in highly myopic patients. High-resolution OCT images can help qualitatively and quantitatively describe the structural characteristics and anatomical changes in highly myopic subjects with and without glaucoma. The ONH and peripapillary area can be analyzed to measure the myopic atrophic-related zone, the existence of intrachoroidal cavitation, staphyloma, and ONH pits by OCT. Similarly, the lamina cribosa observed in the OCT images may reveal anatomical changes that justify visual defects. Several quantitative parameters of the ONH obtained from OCT images were proposed to predict the progression of visual defects in glaucoma subjects. Additionally, OCT images help identify factors that may negatively influence the measurement of the retinal nerve fiber layer (RNFL) and provide better analysis using new parameters, such as Bruch’s Membrane Opening-Minimum Rim Width, which serves as an alternative to RNFL measurements in highly myopic subjects due to its superior diagnostic ability.

Medical Application of Geometric Deep Learning for the Diagnosis of Glaucoma

Purpose

(1) To assess the performance of geometric deep learning in diagnosing glaucoma from a single optical coherence tomography (OCT) scan of the optic nerve head and (2) to compare its performance to that obtained with a three-dimensional (3D) convolutional neural network (CNN), and with a gold-standard parameter, namely, the retinal nerve fiber layer (RNFL) thickness.

Methods

Scans of the optic nerve head were acquired with OCT for 477 glaucoma and 2296 nonglaucoma subjects. All volumes were automatically segmented using deep learning to identify seven major neural and connective tissues. Each optic nerve head was then represented as a 3D point cloud with approximately 1000 points. Geometric deep learning (PointNet) was then used to provide a glaucoma diagnosis from a single 3D point cloud. The performance of our approach (reported using the area under the curve [AUC]) was compared with that obtained with a 3D CNN, and with the RNFL thickness.

Results

PointNet was able to provide a robust glaucoma diagnosis solely from a 3D point cloud (AUC = 0.95 ± 0.01).The performance of PointNet was superior to that obtained with a 3D CNN (AUC = 0.87 ± 0.02 [raw OCT images] and 0.91 ± 0.02 [segmented OCT images]) and with that obtained from RNFL thickness alone (AUC = 0.80 ± 0.03).

Conclusions

We provide a proof of principle for the application of geometric deep learning in glaucoma. Our technique requires significantly less information as input to perform better than a 3D CNN, and with an AUC superior to that obtained from RNFL thickness.

Translational Relevance

Geometric deep learning may help us to improve and simplify diagnosis and prognosis applications in glaucoma.

Anatomic Peculiarities Associated with Axial Elongation of the Myopic Eye

PURPOSE

To describe anatomical peculiarities associated with axial elongation in the human myopic eye.

METHODS

Reviewing the results of previous histomorphometrical investigations of enucleated human globes, as well as reviewing findings obtained in population-based studies and hospital-based clinical investigations of myopic patients and non-myopic individuals.

RESULTS

Myopic axial elongation is associated with a change from a mostly spherical eye shape to a prolate ellipsoid form. It is combined with choroidal and scleral thinning, most pronounced at the posterior pole and less pronounced in the fundus midperiphery. In the fundus midperiphery, the retina and density of the retinal pigment epithelium (RPE) and photoreceptors decrease with a longer axial length, while in the macular region, retinal thickness, RPE cell density, and choriocapillaris thickness are not related to axial length. With axial elongation, a parapapillary gamma zone develops, leading to an enlargement of the optic disc-fovea distance and a decrease in angle kappa. Axial elongation is also correlated with an increase in the surface and volume of Bruch's membrane (BM), while BM thickness remains unchanged. Axial elongation causes moderately myopic eyes to show a shift of BM opening to the foveal direction so that the horizontal disc diameter becomes shorter (with a consequent vertical ovalization of the optic disc shape), a temporal gamma zone develops, and the optic nerve exit takes an oblique course. Features of high myopia are an enlargement of the RPE opening (myopic parapapillary beta zone) and BM opening (secondary macrodisc), elongation and thinning of the lamina cribrosa, peripapillary scleral flange (parapapillary delta zone) and peripapillary choroidal border tissue, secondary BM defects in the macular region, myopic maculoschisis, macular neovascularization, and cobblestones in the fundus periphery.

CONCLUSIONS

These features combined may be explained by a growth in BM in the fundus midperiphery leading to axial elongation.

Change in the ophthalmoscopical optic disc size and shape in a 10-year follow-up: the Beijing Eye Study 2001-2011

BACKGROUND

To assess prevalence and associated factors of changes in the ophthalmoscopic optic disc size and shape.

METHODS

The case-control study included all highly myopic eyes (myopic refractive error ≤-6.0 diopters) and a randomly selected group of non-highly myopic eyes, examined in the population-based Beijing Eye Study 2001 and 2011.

RESULTS

The study included 89 highly myopic eyes (age:65.0±9.8 years) and 86 non-highly myopic eyes. Reduction in ophthalmoscopic disc size (prevalence, high myopia: 30 (33.7%) eyes; non-high myopia: 7 (8.1%) eyes) was associated with non-circular gamma zone enlargement (OR: 19.4; 95% CI: 6.7 to 56.6; p<0.001) and disc-fovea line elongation (OR: 2.80;95% CI: 1.12 to 6.98; p=0.03). Disc size reduction was correlated with a disc diameter shortening in direction of the widest gamma zone enlargement (correlation coefficient r=34; p=0.01). The perpendicular disc diameter remained mostly unchanged, resulting in an ovalisation of the ophthalmoscopic disc shape. Enlargement of the ophthalmoscopic disc size (prevalence, high myopia: 22 (24.7%) eyes; non-high myopia: 4 (4.7%) eyes) was associated with circular gamma zone enlargement (4.99; 95% CI: 1.95 to 12.8; p=0.001) and high myopia (OR: 4.29; 95% CI: 1.34 to 13.8; p=0.01).

CONCLUSIONS

Myopic axial elongation may lead first to a Bruch's membrane (BM) opening (BMO) shift into the foveal direction leading to BM overhanging into the nasal intrapapillary compartment, development and enlargement of gamma zone at the temporal disc side, reduction in the ophthalmoscopically visible disc area and ovalisation of the ophthalmoscopic disc shape. In a second step, an axial elongation-associated BMO enlargement may lead to a circular gamma zone increase and, due to the retraction of BM at the nasal disc border, to an enlargement of the ophthalmoscopically visible optic disc.

Parapapillary gamma zone enlargement in a 10-year follow-up: the Beijing Eye Study 2001-2011

PURPOSE

To assess prevalence and associated factors of parapapillary gamma zone enlargement (GZE).

METHODS

Using fundus photographs and optical coherence tomographic images of participants of the population-based Beijing Eye Study, we examined gamma zone changes in a 10-year follow-up.

RESULTS

The study included 89 highly myopic eyes (61 participants; age: 65.0 ± 9.8 years) and 86 randomly selected non-highly myopic eyes. GZE prevalence was significantly higher in highly myopic eyes than non-highly myopic eyes (75/89; 84%; 95% CI: 77, 92 versus 18/86; 21%; 95% CI:12, 30; p < 0.001). None of the eyes showed a reduction in gamma zone size. Higher prevalence of segmental GZE without enlargement of Bruch's membrane opening (BMO) (mean: 26/175; 14.9%; 95% CI: 9.5, 20.2) was associated with optic disc size reduction (OR: 43.3; 95% CI: 10.9, 172; p < 0.001), disc-fovea distance elongation (OR: 15.4; 95% CI: 3.12, 76.4; p = 0.001) and lower prevalence of high axial myopia (OR: 0.08; 95% CI: 0.01, 0.44; p = 0.001). Higher prevalence of circular GZE (mean: 38/175; 21.7%; 95% CI: 16, 28) was correlated with optic disc enlargement (OR: 4.30; 95% CI: 1.58, 11.7; p = 0.004), and higher prevalence of myopic maculopathy progression (OR: 4.04; 95% CI: 1.60, 10.2; p = 0.003), or alternatively, higher prevalence of high myopia (OR: 4.44; 95% CI: 1.76, 11.2; p = 0.002). Circular GZE or BMO enlargement was associated with lower prevalence of macular BM defect enlargement (p = 0.035). GZE occurred perpendicular to the orientation of myopic lacquer cracks in 12 out of 17 (71%; 95% CI: 46, 95) eyes with lacquer cracks. Segmental GZE occurred in 49 (89%) out of 55 eyes in the same direction as shortening of the disc diameter developed.

CONCLUSIONS

The observations support the possibility of a posterior myopic axial elongation-associated BMO shift, leading to a segmental GZE in non-highly myopic eyes, followed by a circular GZE in highly myopic eyes. Large gamma zone might be protective against macular Bruch's membrane defects.