BRUCH MEMBRANE AND THE MECHANISM OF MYOPIZATION: A New Theory

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.

The structure and function of the human choroid

In this manuscript, the structure of the human choroid is reviewed with emphasis of the macro- and microscopic anatomy including Bruch's membrane, choriocapillaris, Sattler's and Haller's layer, and the suprachoroid. We here discuss the development of the choroid, as well as the question of choroidal lymphatics, and further the neuronal control of this tissue, as well as the pathologic angiogenesis. Wherever possible, functional aspects of the various structures are included and reviewed.

Intravitreal panitumumab and myopic macular degeneration

BACKGROUND

In experimental studies, intravitreally applied antibodies against epidermal growth factor (EGF), EGF family members (amphiregulin, neuregulin-1, betacellulin, epigen, epiregulin) and against the EGF receptor (EGFR) were associated with a reduction in lens-induced axial elongation and decrease in physiological eye elongation in guinea pigs and in non-human primates. Here, we investigated the intraocular tolerability and safety of a fully human monoclonal IgG2-antibody against EGFR, already in clinical use in oncology, as a potential future therapeutic approach for axial elongation in adult eyes with pathological myopia.

METHODS

The clinical, monocentre, open-label, multiple-dose, phase-1 study included patients with myopic macular degeneration of stage 4, who received intravitreal injections of panitumumab in various doses and in intervals ranging between 2.1 months and 6.3 months.

RESULTS

The study included 11 patients (age:66.8±6.3 years), receiving panitumumab injections in doses of 0.6 mg (4 eyes; 1×1 injection, 3×2 injections), 1.2 mg (4 eyes; 1×1 injection, 2×2 injections, 1×3 injections) and 1.8 mg (3 eyes; 1×1 injection, 2×2 injections), respectively. None of the participants showed treatment-emergent systemic adverse events or intraocular inflammatory reactions. Best-corrected visual acuity (1.62±0.47 logarithm of the minimal angle of resolution (logMAR) vs 1.28±0.59 logMAR; p=0.08) and intraocular pressure (13.8±2.4 mm Hg vs 14.3±2.6 mm Hg; p=0.20) remained unchanged. In nine patients with a follow-up of >3 months (mean:6.7±2.7 months), axial length did not change significantly (30.73±1.03 mm vs 30.77±1.19 mm; p=0.56).

CONCLUSIONS

In this open-labelled, phase-1 study with a mean follow-up of 6.7 months, panitumumab repeatedly administered intravitreally up to a dose of 1.8 mg was not associated with intraocular or systemic adverse effects. During the study period, axial length remained unchanged.

TRIAL REGISTRATION NUMBER

DRKS00027302.

Relationship between the structure and microcirculation of the optic disc region and myopic traction maculopathy in highly myopic eyes

PURPOSE

To explore the characteristics and influencing factors structural and microcirculatory of optic disc and peripapillary tissue in eyes with myopia traction maculopathy (MTM).

METHODS

There were 100 eyes from 77 patients in this study. We used 1:1 matching axial length in myopic eyes. Patients were divided into two groups according to the presence or absence of MTM. Fundus structure parameters were obtained by swept source optical coherence tomography (SS-OCT), and the optic disc microcirculation parameters were obtained by OCT angiography (OCTA).

RESULTS

MTM group were older (P = 0.001) and had poorer Best-corrected Visual Acuity (BCVA) (P = 0.011), the optic disc-fovea distance (DFD) was longer (P < 0.019), optic disc tilt was greater (P < 0.001), area of peripapillary atrophy (PPA) was larger (P < 0.001), and PPA/optical disc area (ONH) was higher (P < 0.001). The peripapillary scleral thickness (PST) was lower in the MTM group (P < 0.001). The mean peripapillary choroidal thickness (PCT) (P < 0.001) and PCT in the 10 orientations were significantly lower in the MTM group than in the NMTM group (all P < 0.01). Vascular density in the nasosuperior (NS) region of the optic disc was significantly lower in the MTM group (P = 0.037). The generalized estimating equation suggested that PPA area (P = 0.028), mean PCT (P = 0.008), superior PCT (P = 0.027), inferonasal PCT (P = 0.040), temporoinferior PCT (P = 0.013), and PST (P = 0.046) correlated with MTM. Age, axial length, optic disc tilt, PPA area, mean PCT, and optic disc central zone (0-2 mm) vascular density (all P < 0.05) were significantly correlated with PST.

CONCLUSIONS

The enlarged PPA area and thinner PCT and PST in eyes with MTM are more significant. Lower PST in high myopia was related to abnormalities of PCT and microcirculation.

TRIAL REGISTRATION

Clinical Trial Registration number: ChiCTR2100046590.

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.

Characteristics and Prevalence of Staphyloma Edges at Different Ages in Highly Myopic Eyes

Purpose

The purpose of this study was to determine the characteristics of staphyloma edges in highly myopic eyes and how they progress.

Methods

We conducted a cross-sectional analysis using baseline data and a longitudinal study with follow-up data from 256 patients (447 eyes) with high myopia, with a mean (SD) follow-up of 3.79 (0.78) years. Participants were divided into four age groups: children (<13), youth (13-24), mature (25-59), and elderly (>60). Ultrawide-field swept-source optical coherence tomography was used to analyze staphyloma edges, which were divided into four areas: nasal to the optic disc (OD), superior to the macula, inferior to the macula, and temporal to the macula.

Results

Staphylomas were significantly more prevalent in the mature (42.49%) and the elderly (51.35%) groups than in the children (13%) and youth (9%) groups. Staphyloma edges were predominantly superior to the macula in the mature and elderly groups. In contrast, staphylomas were rare in children and youth, with their edges mainly located nasal to the OD. The edges of staphylomas located superior and temporal to the macula were more likely to be associated with myopic traction maculopathy. During the follow-up period, 11 new staphyloma edges developed primarily in the mature group (64%). Additionally, 12 edges had an increased degree of protrusion over time, with most cases occurring in the mature (75%) group.

Conclusions

The prevalence and location of staphyloma edges show significant variations depending on age. As time progresses, staphyloma edges manifest at distinct sites and increase their protrusion, potentially playing a role in the emergence of fundus complications.

Intraocular cetuximab: Safety and effect on axial elongation in young Guinea pigs with lens-induced myopization

This study aimed to examine the intraocular tolerability of the epidermal growth factor receptor antibody cetuximab, when applied intravitreally, and its effect on axial elongation. Guinea pigs aged 2-3 weeks were subjected to bilateral plano glasses and bilateral lens-induced myopization (LIM) as a single procedure for group I (n = 8) and group II (n = 8), respectively. In the animals of group III (n = 8), group IV (n = 8), and group V (n = 8), the right eyes of the animals, in addition to LIM, received four weekly intravitreal injections of cetuximab (Erbitux®) in doses of 6.25 μg, 12.5 μg, and 25 μg, respectively. As controls, the left eyes, in addition to LIM, received corresponding intraocular injections of phosphate-buffered saline. The animals underwent regular ophthalmoscopic examinations and biometry for axial length measurements. With increasing doses of cetuximab, the inter-eye difference in axial elongation (at study end, left eyes minus right eyes) were significantly the smallest in group I (0.00 ± 0.02 mm) and group II (-0.01 ± 0.02 mm), they were larger in group III (0.04 ± 0.04 mm) and group IV (0.10 ± 0.03 mm), and they were the largest in group V (0.11 ± 0.01 mm). The inter-eye difference in axial elongation enlarged (P < 0.001) with the number of injections applied. Retinal thickness at the posterior pole (right eyes) was significantly thicker in group V than in group II (P < 0.01). The density of apoptotic cells (visualized by TUNEL-staining) did not vary significantly between any of the groups (all P > 0.05). The results suggest that intravitreal injections of cetuximab in young guinea pigs with LIM resulted in a reduction in axial elongation in a dose-dependent and number of treatment-dependent manner. Intraocular toxic effects, such as intraocular inflammation, retinal thinning, or an increased density of apoptotic cells in the retina, were not observed in association with the intravitreally applied cetuximab.

Dynamic changes in ocular shape during human development and its implications for retina fovea formation

The human fovea is known for its distinctive pit-like appearance, which results from the displacement of retinal layers superficial to the photoreceptors cells. The photoreceptors are found at high density within the foveal region but not the surrounding retina. Efforts to elucidate the mechanisms responsible for these unique features have ruled out cell death as an explanation for pit formation and changes in cell proliferation as the cause of increased photoreceptor density. These findings have led to speculation that mechanical forces acting within and on the retina during development underly the formation of foveal architecture. Here we review eye morphogenesis and retinal remodeling in human embryonic development. Our meta-analysis of the literature suggests that fovea formation is a protracted process involving dynamic changes in ocular shape that start early and continue throughout most of human embryonic development. From these observations, we propose a new model for fovea development.

Understanding Posterior Staphyloma in Pathologic Myopia: Current Overview, New Input, and Perspectives

Posterior staphyloma (PS) is considered the hallmark of pathologic myopia and is defined as an outpouching of a circumscribed portion of the eyeball with a radius of curvature smaller than that of the adjacent zone. Although more common in eyes with high myopia, it can affect those without it. The presence of PS is associated with a structurally and functionally worse course of high myopia that can lead to visual disability. Unfortunately, the pathogenesis of PS is unclear so far. Thus, due to the increasing prevalence of myopia which has been further exacerbated by the advent of COVID-19 lockdown, researchers are eager to elucidate the pathogenesis of pathologic myopia and that of its complications, especially PS, which will allow the development of preventive strategies. The aim of this work was to review the morphological characteristics of PS with emphasis on similarities with peripapillary staphyloma and to discuss the pathogenesis of PS considering recent suggestions about that of peripapillary staphyloma.

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.

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.

Characteristics of the Peripapillary Structure and Vasculature in Patients With Myopic Anisometropia

Purpose

To evaluate the interocular differences of the peripapillary structural and vascular parameters and that of association with axial length (AL) in participants with myopic anisometropia using swept-source optical coherence tomography.

Methods

This prospective cross-sectional study included 90 eyes of 45 participants. Each participant's eyes were divided into the more and less myopic eye respectively according to spherical equivalent. The β- and γ-parapapillary atrophy (PPA) areas, Bruch's membrane opening distance, border length, and border tissue angle were measured manually. Peripapillary choroidal vascularity index and choroidal thickness (CT) values in superior, nasal, inferior, and temporal were calculated using a custom-built algorithm based on MATLAB.

Results

The interocular difference in AL and spherical equivalent was 0.62 ± 0.26 mm and -1.50 (-2.13, -1.25) diopters (D), respectively. The interocular difference in spherical equivalent was highly correlated with that of the AL. The β- and γ-PPA areas were significantly greater in more myopic eyes. The mean and inferior peripapillary choroidal vascularity index and all regions of peripapillary CT were significantly lower in the more myopic eyes. The interocular difference in AL was significantly positively correlated with the interocular differences in γ-PPA area and border length and negatively correlated with the interocular differences in temporal choroidal vascularity index and mean, inferior, and temporal peripapillary CT. There was an independent correlation between the interocular differences in AL and the interocular differences in γ-PPA area, inferior, and temporal peripapillary CT.

Conclusions

Significant differences between both groups were detected in most peripapillary parameters, especially in peripapillary CT. The γ-PPA area, border length, and peripapillary CT were significantly correlated with the elongation of AL.

Translational Relevance

The current study characterized and analyzed the peripapillary parameters in myopic anisometropia, which helped to monitor myopic progression.

Evaluation of Retinal Layer Thicknesses in Patients with Keratoconus Using Retinal Layer Segmentation Analysis

OBJECTIVE

To conduct an evaluation of the effects of irregular astigmatism on the retinal nerve fiber layer (RNFL) and the retinal layers observed using spectral-domain optical coherence tomography (SD-OCT) in patients who had keratoconus (KC).

MATERIALS AND METHODS

A total of 255 eyes from 255 individuals, comprising 72 eyes of KC patients, 70 eyes of patients with astigmia, and 113 eyes of healthy controls were included in the analysis. RNFL scan maps (comprising global, temporal, superotemporal, inferotemporal, nasal, inferonasal, and superonasal maps) and macular thickness (MT) maps of a standard from the Early Treatment Diabetic Retinopathy Study (ETDRS) grid were assessed. The measurements were segmented automatically using Spectralis software, and included the RNFL, inner and outer plexiform layers (IPL, OPL), inner and outer nuclear layers (INL, ONL), ganglion cell layer, retinal pigment epithelium (RPE) in the central 6-mm ETDRS subfield.

RESULTS

The RNFL thickness in the KC group was lower when compared with the other two groups; however, statistically significant differences were noted in the global, temporal, superotemporal, and inferotemporal sectors (p < 0.05 for all). All of the central MT parameters showed significant variation among the groups, while a statistically significant decrease was noted in the KC group, except in the inferior outer sector (p = 0.741). In the segmentation analysis, the KC group had the significantly lowest IPL, ONL, RPE, and outer retinal layer (ORL) thickness among the groups (p < 0.05 for each). The astigmatic group was similar to the control group with regard to these parameters (p > 0.05 for each).

CONCLUSION

The eyes in the KC group appeared to have a thinner RNFL and MT when compared to those in the astigmatic and control groups. The ORLs, especially the ONL and RPE, were the most affected component of the macula in the KC group.

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.

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

Myopic axial elongation is associated with various non-pathological changes. These include a decrease in photoreceptor cell and retinal pigment epithelium (RPE) cell density and retinal layer thickness, mainly in the retro-equatorial to equatorial regions; choroidal and scleral thinning pronounced at the posterior pole and least marked at the ora serrata; and a shift in Bruch's membrane opening (BMO) occurring in moderately myopic eyes and typically in the temporal/inferior direction. The BMO shift leads to an overhang of Bruch's membrane (BM) into the nasal intrapapillary compartment and BM absence in the temporal region (i.e., parapapillary gamma zone), optic disc ovalization due to shortening of the ophthalmoscopically visible horizontal disc diameter, fovea-optic disc distance elongation, reduction in angle kappa, and straightening/stretching of the papillomacular retinal blood vessels and retinal nerve fibers. Highly myopic eyes additionally show an enlargement of all layers of the optic nerve canal, elongation and thinning of the lamina cribrosa, peripapillary scleral flange (i.e., parapapillary delta zone) and peripapillary choroidal border tissue, and development of circular parapapillary beta, gamma, and delta zone. Pathological features of high myopia include development of macular linear RPE defects (lacquer cracks), which widen to round RPE defects (patchy atrophies) with central BM defects, macular neovascularization, myopic macular retinoschisis, and glaucomatous/glaucoma-like and non-glaucomatous optic neuropathy. BM thickness is unrelated to axial length. Including the change in eye shape from a sphere in emmetropia to a prolate (rotational) ellipsoid in myopia, the features may be explained by a primary BM enlargement in the retro-equatorial/equatorial region leading to axial elongation.

Analysis of Bilaterality and Symmetry of Posterior Staphyloma in High Myopia

The purpose of this study was to examine bilaterality and symmetry of posterior staphyloma (PS) in high myopic eyes. Methods: This cross-sectional and non-interventional study assessed 473 high myopic eyes [axial length (AL) ≥ 26 mm] of 259 patients. Patients underwent an ophthalmological examination including multimodal-imaging and myopic maculopathy grading according to Atrophic/Tractional/Neovascular (ATN) system, presence and subtype of PS, and severe pathologic myopia (PM). Bilaterality of PS and subtype's symmetry between eyes of the same patient was assessed. Four groups were analyzed: (1) bilateral vs. unilateral PS's eyes. Within bilateral group, symmetric vs. asymmetric subtypes according to (2) Curtin's classification, (3) Ohno-Matsui's classification, and (4) primary/compound subtypes. Results: Out of the total, 334 myopic eyes of 167 patients were included. The 92.8% (n = 310/334) of the eyes presented PS and was bilateral in 85.6% (n = 143/167) of the patients. Bilateral eyes showed significantly (p < 0.01) greater AL, severe PM, A and N components vs. unilateral PS. AL-difference between both eyes was greater in unilateral PS (p < 0.01). Among bilateral PS, the subtype was symmetric in 79 (55.2%), 84 (58.7%), and 115 (80.4%) patients according to Curtin's classification, Ohno-Matsui's classification, and primary/compound; respectively. The asymmetric group presented worse best-corrected visual acuity (p < 0.01), higher AL (p < 0.01), incidence of PM, and severe PM (p < 0.05). Conclusions: PS was bilateral in most of the patients without clinical differences between both eyes, being symmetrical in more than half of bilateral cases. Patients with bilateral PS showed higher myopic maculopathy, AL, and incidence of severe PM than unilateral PS.

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.

Macular outer nuclear layer, ellipsoid zone and outer photoreceptor segment band thickness, axial length and other determinants

The study aims to assess the thickness of the retinal outer nuclear layer (ONL), ellipsoid zone (EZ) and photoreceptor outer segment (POS) band in various macular regions and its associations with axial length and other parameters. Participants of the Beijing Eye Study 2011 underwent a series of examinations including spectral-domain optical coherence tomography of the macula. The current study included 2213 participants without retinal or optic nerve diseases (age: 61.7 ± 8.4 years; range 50-93 years); axial length: 23.15 ± 0.95 mm; range 18.96-29.15 mm). The ONL (fovea: 98.9 ± 8.8 µm), EZ (fovea: 24.1 ± 0.5 µm) and POS band (fovea: 24.3 ± 3.5 µm) were the thickest (P < 0.001) in the fovea (defined as the thinnest central point), followed by the temporal inner, nasal inner, inferior inner, superior inner, inferior outer, temporal outer, nasal outer, and superior outer region. In multivariable analysis, a thicker retinal ONL was associated (correlation coefficient r: 0.40) with shorter axial length (beta: - 0.14; P < 0.001) and shorter disc-fovea distance (beta: - 0.10; P = 0.001), after adjusting for younger age (beta: - 0.26; P < 0.001), male sex (beta: 0.24; P < 0.001), lower serum cholesterol concentration (beta: - 0.05; P = 0.04), and thicker subfoveal choroidal thickness (beta: 0.08; P < 0.001). The POS thickness increased with shorter axial length (beta: - 0.06; P < 0.001) and shorter optic disc-fovea distance (beta: - 0.05; P = 0.03), after adjusting for younger age (beta: - 0.34; P < 0.001), male sex (beta: 0.15; P < 0.001), and thicker subfoveal choroidal thickness (beta: 0.24; P < 0.001). As a conclusion, the photoreceptor ONL, EZ and POS band vary in thickness between different macular regions and differ in their correlations with axial length, disc-fovea distance, age, sex, and subfoveal choroidal thickness. The ONL thickness decrease with longer axial length and longer disc-fovea distance may point to an axial elongation-associated retinal stretching in the macula.

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

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

Central corneal thickness and its associations in a Russian population. The Ural eye and Medical Study

BACKGROUND

To assess central corneal thickness (CCT) and its associations in a Russian population.

METHODS

The population-based Ural Eye and Medical Study included 5899 (80.5%) out of 7328 eligible individuals. As part of an ophthalmological and general examination, CCT was measured by Scheimflug imaging.

RESULTS

The study included 5792 (98.2%) participants (age:58.8 ± 10.6 years;range: 40-94 years) with available bilateral CCT measurements. Mean CCT was larger in Russians than non-Russians (549.5 ± 32.8 µm versus 539.2 ± 33.9 µm; P < 0.001). In multivariable analysis, thicker CCT was associated (regression coefficient r:0.43) with younger age (standardized regression coefficient beta:-0.09; non-standardized regression coefficient B:-0.29;95% confidence interval (CI):-0.39,-0.20; P < 0.001), male sex (beta:0.05; B:3.10; 95%CI:1.18,5.03; P = 0.002), urban region of habitation (beta:0.10; B:6.83; 95%CI:4.61, 9.05; P < 0.001), Russian ethnicity (beta:0.04; B:3.48; 95%CI:1.04, 5.91; P = 0.005), higher level of education (beta:0.04; B:0.97;95%CI:0.29,1.66; P = 0.006), higher serum bilirubin concentration (beta:0.05;B:0.15; 95%CI:0.07,0.23;P < 0.001), lower corneal refractive power (beta:-0.09;B:11.92; 95%CI:-2.50,-1.35; P < 0.001), smaller anterior chamber angle (beta:-0.07;B:-0.38;95%CI:-0.52,-0.24;P < 0.001), higher IOP readings (beta:0.38; B:3.47; 95%CI:3.21,3.73; P < 0.001), and higher rise in IOP readings by medical mydriasis (beta:0.07; B:0.88;95%CI:0.54,1.22;P < 0.001). In that model, CCT was not associated with body height (P = 0.14), previous cataract surgery (P = 0.10), axial length (P = 0.18) or prevalence of glaucoma (P = 0.11). The mean inter-eye difference in CCT was 8.52 ± 13.9 µm (median:6.0;95CI:8.16,8.88). A higher inter-eye CCT difference was associated with older age (beta:0.08; B:0.11;95%CI:0.07,0.15; P = 0.01), lower level of education (beta:-0.04;B:-0.34; 95%CI:-0.60,-0.08; P < 0.001) and status after cataract surgery (beta:0.04; B:2.92;95%CI:1.02,4.83; P = 0.003).

INTRODUCTION CONCLUSIONS

In this ethnically mixed population from Russia with an age of 40+ years, mean CCT (541.7 ± 33.7 µm) was associated with parameters such as younger age, male sex, Russian ethnicity, and higher educational level. These associations may be taken into account when the dependence of IOP readings on CCT are considered. Glaucoma prevalence was unrelated to CCT.

Retinal peripapillary microvasculature in indirect traumatic optic neuropathy predicted prognosis of endoscopic trans-ethmosphenoid optic canal decompression

PURPOSES

The purpose of this study is to quantify the alteration of retinal peripapillary microvasculature and structure in unilateral indirect traumatic optic neuropathy (ITON) and figure out predicted factors of visual improvement for ITON patients with endoscopic trans-ethmosphenoid optic canal decompression (ETOCD) after one month.

METHODS

Twenty healthy controls and 72 unilateral ITON patients were included. Optical coherence tomography angiography was used to analyse radial peripapillary capillary (RPC) density, peripapillary retinal nerve fibre layer (pRNFL) thickness, superficial retinal capillary plexus (SRCP) and deep retinal capillary plexus (DRCP) density. Associations between preoperative parameters and postoperative best-corrected visual acuity (BCVA) were determined. The receiver operating characteristic (ROC) curves were used to figure out predicted factors of visual improvement for ITON after ETOCD one month.

RESULTS

In ITON eyes, the preoperative global RPC density, pRNFL thickness and SRCP density were reduced compared with unaffected eyes (p ≤ 0.001). Multivariate linear regression showed that preoperative global RPC density (Standardized β = -0.273), SRCP density (Standardized β = -0.183), DRCP density (Standardized β = -0.098) and preoperative BCVA (Standardized β = 0.795) were associated with the postoperative BCVA (All p < 0.001). The area under the curve (AUC) of preoperative global RPC density to predict visual improvement after ETOCD was 0.816, while the AUCs of preoperative BCVA, global pRNFL thickness, SRCP and DRCP density were 0.575, 0.756, 0.516 and 0.615, respectively.

CONCLUSIONS

The alteration of peripapillary area, especially the reduced RPC density, occurred in ITON eyes. The preoperative RPC density was associated with postoperative BCVA and was shown to be highly predictive for visual improvement after ETOCD one month.

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.

The characteristics of dome-shaped macula in Chinese children aged 4-6 years using optical coherence tomography angiography

PURPOSE

To evaluate the characteristics of dome-shaped macula (DSM) in children aged 4-6 years with normal visual acuity using optical coherence tomography angiography.

METHOD

This is a cross-sectional study. A total of 19 children aged 4-6 years were included. The results of optical coherence tomography angiography images were analysed to identify and quantify retinal structural and vascular parameters in DSM children. The dome height, dome base, and sub-dome choroidal thickness were manually measured. Participants with DSM and those without DSM from our previous study were compared on these parameters.

RESULTS

Nineteen eyes of the preschool subjects with normal visual acuity showed horizontal DSM on optical coherence tomography (OCT). The DSM was significantly smooth and low in the children, and we did not observe differences between sex and age. Compared to the children without DSM, the average axial length was longer, and the average macular vessel density was lower in the DSM group, especially in the deep retinal vascular density. Additionally, the dome height was positively correlated with the sub-dome choroidal thickness. When the dome base/height was increased, the fovea avascular zone (FAZ) area was larger.

CONCLUSION

Dome-shaped macula was detected in the preschool children in the process of the emmetropization with normal visual acuity. The changes in macular structure and vasculature provide new ideas for further investigation into the characteristics of DSM formation.

Myopic macular Bruch's membrane defects

Purpose

To examine histologic characteristics of macular Bruchś membrane defects (BMD) in axially elongated eyes.

Design

Histomorphometric study.

Methods

Using light microscopy, we examined enucleated human globes for BMDs.

Results

In 247 eyes, BMDs were detected in 15 (6.1%) eyes (axial length:27.0-36.0 mm), in 10 of them in the macular region. Prevalence and size of BMDs (mean:1.93 ± 1.62 mm; range:0.22mm-6.24 mm) correlated with longer axial length (OR:1.52; 95%CI:1.19,1.94; P = 0.001) and higher prevalence of scleral staphylomas (OR:16.3; 95%CI:2.67,99.3; P < 0.001). The BMDs were smaller than corresponding gaps in the retinal pigment epithelium (RPE) (1.93 ± 1.62 mm versus 2.61 mm ± 1.73 mm; P = 0.003), and larger than corresponding gaps in the inner nuclear layer (0.43 ± 0.76 mm; P = 0.008) and inner limiting membrane bridges (0.13 ± 0.33 mm; P = 0.001). Choriocapillaris thickness, BM thickness and RPE cell density did not vary (all P > 0.05) between the BDM border and adjacent areas. In the BMD, choriocapillaris and RPE were absent. The sclera was thinner in the BDM area than in adjacent areas (0.28 ± 0.19 mm versus 0.36 ± 0.13 mm; P = 0.006).

Conclusions

BMDs as hallmarks of myopic macular degeneration are characterized by longer gaps in the RPE and smaller gaps in the outer nuclear layer and inner nuclear layer, by localized scleral thinning, and by a spatial association with scleral staphylomas. Thickness of the choriocapillaris and density of the RPE cell layer, both absent within the BDMs, do not vary between the BMD border and adjacent regions. The results suggest an association between BDMs and absolute scotomas, stretching of the adjacent retinal nerve fiver layer, and an axial elongation-associated stretching effect on BM as etiology of the BDMs.

Inner limiting membrane bridges within Bruch's membrane defects in pathological myopia

The purpose of the study was to examine peculiarities of the inner limiting membrane (ILM) in axially elongated eyes. The histomorphometric study included human globes enucleated due to reasons such as painful secondary angle-closure glaucoma or malignant uveal melanomas. Using light microscopy, we searched for regions with ILM-specific features in association with a marked axial elongation. Out of 279 eyes (279 patients) (mean age: 61.8 ± 13.9 years; axial length: 25.5 ± 3.1 mm (range: 20.0-37.0 mm)), two eyes (axial length: 30 mm and 34 mm, respectively) showed one region and two regions, respectively, characterized by ILM presence and absence of all other retinal layers, retinal pigment epithelium, Bruch´s membrane (BM) and choroid. The length of these regions, called ILM-bridges, was 1.06 mm, 0.73 mm, and 0.62 mm, respectively. All ILM-bridges were spatially associated with a larger, underlying BM defect and with localized scleral thinning without a staphylomatous scleral configuration. The distance between the ILM-bridges and the optic disc ranged between 1.92 mm and 4.21 mm. In univariable analysis, ILM-bridge number increased with longer axial length (beta: 0.19; P = 0.002) and higher BM defect prevalence (beta: 0.21; P = 0.001), while in multivariable analysis, the ILM-bridges number remained to be significantly correlated only with a higher prevalence of BM defect (beta: 0.15; P = 0.048). ILM-bridges occur in eyes with pathologic myopia in spatial association with underlying, larger BM defects. They may be due to an axial elongation-associated local stretching and rupture of all other retinal layers, caused by the BM defect-related enlargement of the retinal undersurface. Future studies may explore whether these histologic observations support the notion of the ILM having a relatively high biomechanical strength against myopic stretching-associated forces.

Photoreceptor density in relation to axial length and retinal location in human eyes

The purpose of the study was to examine the density of retinal photoreceptors and retinal pigment epithelium (RPE) cells in relation to myopic axial elongation in human eyes. Using light microscopy, we assessed the density of photoreceptors and RPE cells at the ora serrata, equator, and midperiphery (equator/posterior pole midpoint), and the RPE cell density additionally at the posterior pole, in enucleated human globes. The study included 78 eyes (mean age: 59.2 ± 15.6 years; range: 32-85 years) with a mean axial length of 27.3 ± 3.6 mm (range: 21.5-37.0 mm). Close to the ora serrata, at the equator and midperiphery, photoreceptor and RPE cell density was 246 ± 183, 605 ± 299 and 1089 ± 441 photoreceptors/mm and 56.1 ± 13.7, 45.2 ± 15.1, and 48.8 ± 15.6 RPE cells/mm, respectively. Densities of both cell types in all three regions were positively correlated with each other (all P < 0.001) and decreased with longer axial length (all P < 0.001) and longer distance between the ora serrata and the posterior pole (all P < 0.001), most marked at the midperiphery and least marked close to the ora serrata. The PRE cell density at the posterior pole was not significantly (P = 0.35) related to axial length. The photoreceptor density at the ora serrata (beta:- 0.33) and equator (beta: - 0.27) and RPE cell density at the ora serrata (beta: - 0.27) decreased additionally with the presence of glaucoma. The findings suggest that the axial elongation-related decrease in photoreceptor and RPE cell density is most marked at the midperiphery, followed by the equator and finally the ora serrata region. It suggests that the axial elongation-related enlargement of the eye wall predominantly takes place in the retro-equatorial region, followed by the equatorial region.

Morphological characteristics of the optic nerve head and impacts on longitudinal change in macular choroidal thickness during myopia progression

PURPOSE

The aim of this study was to investigate the association between morphological characteristics of Bruch's membrane opening distance (BMOD), border length (BL), border tissue angle (BTA), peripapillary atrophy (PPA) as well as axial length (AL) and incident decreased macular choroidal thickness (mChT) in young healthy myopic eyes.

METHODS

A total of 323 participants aged 17-30 years were included in the current 2-year longitudinal study. Each participant underwent detailed ocular examinations at baseline and follow-up. Data of AL, refraction error, PPA area, BMOD, BL, BTA and mChT were measured individually. Incident decreased mChT was defined as follow-up mChT of participants decreased into the lowest quartile of baseline mChT.

RESULTS

Subjects with longer AL, longer BMOD were more likely to have incident decreased mChT (odds ratio [OR], 1.56; 2.09, respectively, per 1 Z-score increment), whereas larger BTA was less likely to develop decreased mChT (odds ratio [OR], 0.51, per 1 Z-score increment). The area under the receiver operating curve (AUROC) of basic risk model for incident decreased mChT was 0.6284. After adding BMOD, BTA and AL separately to the basic risk model, the AUROC of the combination could reach 0.6967, 0.6944 and 0.7383, respectively. After combining BMOD, BTA and AL to the basic model, the AUROC of the combination showed the highest AUROC of 0.7608.

CONCLUSIONS

Bruch's membrane opening distance and AL are significant risk factors for incident decreased mChT, whereas BTA played protective role in the deterioration of mChT. In addition, a combination of BMOD, BTA and AL could serve as earlier predictors of the attenuation of mChT in myopia progression.

Axial Length and Choriocapillaris Flow Deficits in Non-pathological High Myopia

PURPOSE

To examine the relationship between axial length (AL) and choriocapillaris (CC) flow deficits percentage (FD%) in non-pathological highly myopic eyes.

DESIGN

Prospective cross-sectional study.

METHODS

This study included Chinese patients with non-pathological high myopia, which was defined by an AL of > 26 mm and a META-PM classification grade of <2. Swept-source optical coherence tomography angiography was used to obtain 6 × 6 mm images of the macular CC. The CC FD% was measured in the fovea, parafovea, and perifovea subfields.

RESULTS

A total of 1017 individuals (1017 eyes) with a mean age of 35.95 ± 14.11 years were included. After adjusting for age, sex, intraocular pressure, body mass index, systolic blood pressure, and image quality score, the overall CC FD% increased by 0.27% (95% CI 0.02, 0.52; P = .034) for each mm increase in AL. Among subfields, longer AL was associated with a higher CC FD% in the perifovea (β = 0.53, 95% CI 0.30, 0.77; P < .001), and was not associated with a higher CC FD% in the parafovea (β = 0.08, 95% CI -0.26, 0.42; P = .652) and fovea (β = 0.001, 95% CI -0.50, 0.50; P = .999).

CONCLUSIONS

The CC FD% increased with a longer AL in high myopia in the perifovea region but not in the fovea and parafovea fields. These findings may be of interest in elucidating the etiology of myopic axial elongation.

In Vivo Retinal Pigment Epithelium Imaging using Transscleral Optical Imaging in Healthy Eyes

Objective

To image healthy retinal pigment epithelial (RPE) cells in vivo using Transscleral OPtical Imaging (TOPI) and to analyze statistics of RPE cell features as a function of age, axial length (AL), and eccentricity.

Design

Single-center, exploratory, prospective, and descriptive clinical study.

Participants

Forty-nine eyes (AL: 24.03 ± 0.93 mm; range: 21.9-26.7 mm) from 29 participants aged 21 to 70 years (37.1 ± 13.3 years; 19 men, 10 women).

Methods

Retinal images, including fundus photography and spectral-domain OCT, AL, and refractive error measurements were collected at baseline. For each eye, 6 high-resolution RPE images were acquired using TOPI at different locations, one of them being imaged 5 times to evaluate the repeatability of the method. Follow-up ophthalmic examination was repeated 1 to 3 weeks after TOPI to assess safety. Retinal pigment epithelial images were analyzed with a custom automated software to extract cell parameters. Statistical analysis of the selected high-contrast images included calculation of coefficient of variation (CoV) for each feature at each repetition and Spearman and Mann-Whitney tests to investigate the relationship between cell features and eye and subject characteristics.

Main Outcome Measures

Retinal pigment epithelial cell features: density, area, center-to-center spacing, number of neighbors, circularity, elongation, solidity, and border distance CoV.

Results

Macular RPE cell features were extracted from TOPI images at an eccentricity of 1.6° to 16.3° from the fovea. For each feature, the mean CoV was < 4%. Spearman test showed correlation within RPE cell features. In the perifovea, the region in which images were selected for all participants, longer AL significantly correlated with decreased RPE cell density (R Spearman, Rs = -0.746; P < 0.0001) and increased cell area (Rs = 0.668; P < 0.0001), without morphologic changes. Aging was also significantly correlated with decreased RPE density (Rs = -0.391; P = 0.036) and increased cell area (Rs = 0.454; P = 0.013). Lower circular, less symmetric, more elongated, and larger cells were observed in those > 50 years.

Conclusions

The TOPI technology imaged RPE cells in vivo with a repeatability of < 4% for the CoV and was used to analyze the influence of physiologic factors on RPE cell morphometry in the perifovea of healthy volunteers.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Safety and tolerability of intravitreal cetuximab in young and adult rabbits

To assess safety and tolerability of intraocularly applied cetuximab as epidermal growth factor receptor antibody, we conducted the experimental study which consisted of groups of adult rabbits (body weight: 2.4 kg) and young rabbits (body weight: 1.6 kg). All animals received three intravitreal injections of 0.5 mg cetuximab (Erbitux) (0.10 mL; 5 mg cetuximab/mL) into their right eyes in 4-week intervals, while the contralateral eyes received intravitreal injections of Ringer's solution. All animals underwent regular ophthalmological examinations at baseline and two-week intervals. Four weeks after the last injection, the animals were sacrificed, and the eyes were enucleated, fixed and examined by light microscopy. The study included 10 adult rabbits (age: 18 weeks; range: 17–19 weeks) and 8 young rabbits (age: 8 weeks; range: 7–10 weeks). Biometric measurements of axial length, anterior chamber depth and lens thickness and intraocular pressure readings did not differ significantly (all P > 0.05, Bonferroni corrected) between the right (study) eyes and the left (control) eyes, neither in the young nor in the adult rabbit group. Signs of intraocular inflammation or fundus peculiarities were not detected. Thickness of the outer nuclear layer, inner nuclear layer, combined outer and inner nuclear layer and outer plexiform layer, and total retina, measured at the posterior pole, posterior pole/equator midpoint, equator, and ora serrata region, did not vary significantly between study eyes and control eyes (all P > 0.05, Bonferroni corrected). The results suggest that repeated intravitreal application of cetuximab did not result in any detected intraocular toxic or destructive effect in young and adult rabbits, concurring with the notion of an intraocular tolerability of cetuximab.

Characteristics of the Optic Nerve Head in Myopic Eyes Using Swept-Source Optical Coherence Tomography

Purpose

To investigate the characteristics of the optic nerve head (ONH) in myopia using swept-source optical coherence tomography (SS-OCT).

Methods

Participants were divided into three groups according to the axial length (AL). The optic disc morphology, retinal nerve fiber layer (RNFL) thickness, and radial peripapillary capillary (RPC) vessel density (VD), optic disc tilt, rotation, Bruch's membrane opening distance (BMOD), border length (BL), border tissue angle, focal lamina cribrosa (LC) defects, β- and γ-zone peripapillary atrophy (PPA), microvasculature dropout (MvD), choroidal thickness (CT), and the choroidal vascularity index (CVI) were compared. Linear regression analysis evaluated relationships between spherical equivalent, AL, and ONH parameters.

Results

One hundred five, 98, and 118 eyes were included in groups 1, 2, and 3, respectively. With AL increasing, the mean, superior and temporal CT, central mean and temporal, pericentral mean, inferior and nasal RPC VD, and temporal CVI decreased, whereas the mean and temporal RNFL thickness, optic disc, RIM and β-PPA area, presence and area of γ-PPA, BMOD and BL increased. Compared to other groups, group 3 depicted a larger cup area, more focal LC defect and total and juxtapapillary MvD; a lower central superior, inferior and nasal, pericentral superior, and temporal RPC VD. Group 1 demonstrated more tilted disc, larger inferior and nasal CT, mean, superior, inferior, and nasal CVI.

Conclusions

Myopia eyes have larger ONH changes, PPAs, regional RNFL, and MvD, but smaller regional CTs, RPC VD, and CVIs. SS-OCT may be useful in detecting ONH variations during myopia.

Progression and associated factors of lacquer cracks/patchy atrophies in high myopia: the Beijing Eye Study 2001-2011

PURPOSE

To assess the development and progression of lacquer cracks/patchy atrophies (LCs/PAs) in high myopia.

METHODS

The case control study included highly myopic eyes (refractive error ≤  - 6.0 diopters), examined in the population-based Beijing Eye Study 2001/2011. Using fundus photographs taken in 2001 and 2011 and optical coherence tomographic images obtained in 2011, we assessed the incidence and enlargement of pre-existing LC/PAs.

RESULTS

The study included 89 highly myopic eyes (age: 65.0 ± 9.4 years). Newly developed or enlarged LC/PAs were detected in 17 (19.1%; 95% confidence interval (CI): 11.0, 27.0) eyes, with a new LC development without previous LCs, enlargement of a pre-existing LC, LC enlargement to a PA, development of a new PA without any previous LCs, and enlargement of a pre-existing PA detected in 3, 3, 5, 3, and 3 eyes, respectively. In 14 (82.4%; 95%CI: 62.3, 100) of the 17 eyes with LC/PA development or enlargement, the LC/PAs elongated perpendicularly to, and widened in, the direction of gamma zone enlargement. Higher prevalence of LC/PA enlargement was associated (multivariable analysis) with higher myopic maculopathy stage in 2001 (odds ratio (OR): 7.83; 95%CI: 2.65, 23.2; P < 0.001) and higher frequency of parapapillary delta zone enlargement (OR: 32.0; 95%CI: 3.07, 334; P < 0.001). Prevalence of LC/PA enlargement was lower than the prevalence of changes in other myopic maculopathy features (disc-fovea distance elongation: 71%; choroidal vessel shift: 55%; reduction in ophthalmoscopical disc size: 34%; ophthalmoscopic disc size enlargement: 25%). All eyes with LC/PA enlargement showed a pre-existing and enlarging gamma zone.

CONCLUSIONS

Development and enlargement of LC/PAs were associated with enlargement of parapapillary delta zone and often occurred in association with the direction of gamma zone enlargement.

Epiregulin, epigen and betacellulin antibodies and axial elongation in young guinea pigs with lens-induced myopization

Background

To examine an effect of intravitreally applied antibodies against epidermal growth factor family members, namely epiregulin, epigen and betacellulin, on ocular axial elongation.

Methods

The experimental study included 30 guinea pigs (age:3–4 weeks) which underwent bilateral lens-induced myopization and received three intraocular injections of 20 µg of epiregulin antibody, epigen antibody and betacellulin antibody in weekly intervals into their right eyes, and of phosphate-buffered saline into their left eyes. Seven days after the last injection, the animals were sacrificed. Axial length was measured by sonographic biometry.

Results

At baseline, right eyes and left eyes did not differ (all P > 0.10) in axial length in neither group, nor did the interocular difference in axial length vary between the groups (P = 0.19). During the study period, right and left eyes elongated (P < 0.001) from 8.08 ± 0.07 mm to 8.59 ± 0.06 mm and from 8.08 ± 0.07 mm to 8.66 ± 0.07 mm, respectively. The interocular difference (left eye minus right eye) in axial elongation increased significantly in all three groups (epiregulin-antibody:from 0.03 ± 0.06 mm at one week after baseline to 0.16 ± 0.08 mm at three weeks after baseline;P = 0.001); epigen-antibody group:from -0.01 ± 0.06 mm to 0.06 ± 0.08 mm;P = 0.02; betacellulin antibody group:from -0.05 ± 0.05 mm to 0.02 ± 0.04 mm;P = 0.004). Correspondingly, interocular difference in axial length increased from -0.02 ± 0.04 mm to 0.13 ± 0.06 mm in the epiregulin-antibody group (P < 0.001), and from 0.01 ± 0.05 mm to 0.07 ± 0.05 mm in the epigen-antibody group (P = 0.045). In the betacellulin-antibody group the increase (0.01 ± 0.04 mm to 0.03 ± 0.03 mm) was not significant (P = 0.24).

Conclusions

The EGF family members epiregulin, epigen and betacellulin may be associated with axial elongation in young guinea pigs, with the effect decreasing from epiregulin to epigen and to betacellulin.

Reduced Radial Peripapillary Capillary in Pathological Myopia Is Correlated With Visual Acuity

Purpose

To quantify the radial peripapillary capillary (RPC) density and the peripapillary retinal nerve fiber layer (pRNFL) thickness in pathological myopia and examine associations among these factors and best-corrected visual acuity (BCVA).

Methods

The cohort was composed of 41 eyes as control and 79 eyes with high myopia (59 simple high myopia, 20 pathological myopia). Optical coherence tomography angiography was done to obtain RPC density and pRNFL thickness, superficial retinal capillary plexus (SRCP), and deep retinal capillary plexus (DRCP) density. The axial length (AL) was measured. Correlations among BCVA, RPC density, pRNFL thickness, AL, and other parameters were determined.

Results

For pathological myopia, the densities of RPC, SRCP, and DRCP were significantly less than those of the control and simple high myopia groups (p ≤ 0.005). There was no statistical difference in pRNFL thickness between pathological myopia and simple high myopia (p = 0.063), whereas there was significant difference in global pRNFL thickness between pathological myopia and control (p = 0.008). The global RPC density showed the greatest area under the curve (AUC = 0.962, sensitivity = 94.74%, specificity = 90.00%, cutoff value = 47.8%) for pathological myopia, whereas the AUC of pRNFL thickness, SRCP, and DRCP were only 0.675, 0.824, and 0.865, respectively. The univariate and multiple linear regression models showed that RPC density, SRCP density, and AL were correlated with BCVA (All p < 0.05). In the final BCVA model with multiple generalized estimating equation analysis, AL, RPC density and interaction between RPC and AL were shown (all p < 0.03). For an eye with AL ≥ 27.94 mm, global RPC density was predicted to be less than 48.77% with a high risk of visual impairment.

Conclusion

Peripapillary alterations, both the decreasing RPC density and pRNFL thickness, occurred in pathological myopia compared with the control. The RPC density was associated with BCVA, and this relationship was affected by AL.

Choriocapillaris Flow Deficits in Normal Chinese Imaged by Swept-Source Optical Coherence Tomographic Angiography

PURPOSE

To evaluate the ocular and systemic determinants of the choriocapillaris flow deficits percentage (CC FD%) in normal eyes.

DESIGN

Observational cross-sectional study.

METHODS

Healthy Chinese participants without ocular or systemic diseases underwent detailed ophthalmic evaluations, including swept-source optical coherence tomography angiography (SS-OCTA) with 6- × 6-mm macular choriocapillaris images. The CC FD% was assessed in circular regions with diameters of 1.0 and 5.0 mm, rings with 1.0- to 2.5-mm diameters, and rings with 2.5- to 5.0-mm diameters.

RESULTS

The study included 830 individuals (mean ± SD age 58.66 ± 8.75 years). CC FD% (mean ± SD 22.05% ± 1.13%) was the lowest in the 2.5- to 5.0-mm ring, followed by the 1.0- to 2.5-mm ring, and highest in the 1.0-mm circle. In multivariable analysis, a higher CC FD% was associated with older age (β = 0.16 [95% confidence interval {CI}] 0.08-0.24, P < .001), higher intraocular pressure (β = 0.34 [95% CI 0.25-0.42], P < .001), higher serum concentrations of high-density lipoprotein cholesterol (β = 0.24 [95% CI 0.17-0.32], P < .001), and lower image quality score (β = -0.22 [95% CI -0.30 to -0.14], P < .001). CC FD% was also independent of axial length.

CONCLUSIONS

In healthy adult Chinese individuals, a higher CC FD% was associated with older age, higher intraocular pressure, and higher high-density lipoprotein cholesterol serum concentration. These factors may influence clinical assessments of the choriocapillaris. The lack of an association between CC FD% and axial length is consistent with similar findings for Bruch membrane thickness, macular retinal thickness, and macular retinal pigment epithelium cell density.

Histopathology of myopic cobblestones

PURPOSE

To search for the histological correlate of peripheral 'cobblestones' in highly myopic eyes.

METHODS

The histomorphometric investigation included histologic sections of enucleated eyes of Caucasian patients. Using light microscopy, we measured the thickness of the retina, Bruch's membrane (BM) and choriocapillaris.

RESULTS

The study included 50 eyes (mean age:60.6 ± 18.7 years;axial length:26.5 ± 3.8 mm), with cobblestone regions detected in 7 eyes. BM thickness and choriocapillaris thickness in the cobblestone region were thinner (1.1 ± 0.2 µm versus 2.4 ± 0.8 µm; p < 0.001 and 1.6 ± 0.5 µm versus 2.6 ± 1.9 µm; p = 0.02, respectively), and just outside of the cobblestone region they were thicker (3.3 ± 0.6 µm versus 2.4 ± 0.8 µm; p = 0.005 and 5.7 ± 1.6 µm versus 2.6 ± 1.9 µm; p = 0.002, respectively) than in corresponding regions of eyes without cobblestones. Within the group of eyes with cobblestones, BM thickness (1.1 ± 0.2 mm versus 3.3 ± 0.6 mm; p < 0.001), choriocapillaris thickness (1.6 ± 0.5 mm versus 5.7 ± 1.6 mm; p < 0.001) and choriocapillaris density (48±15 µm/300 µm versus 159 ± 66 µm/300 µm;PP=0.002) were significantly lower in the cobblestone region than just outside of the cobblestone region. The cobblestone regions were characterized by firm adhesion of disorganized retina with thinned BM, few retinal pigment epithelium (RPE) islands within cobblestone regions, and absence of regional scleral or overall choroidal thinning. BM was mono-layered within, and double-layered outside of cobblestone regions, with the inner layer missing within the cobblestone region (except for the RPE islands).

CONCLUSIONS

Peripheral cobblestone regions in highly myopic eyes are characterized by marked BM thinning with absence of an inner BM layer, almost complete RPE absence, choriocapillaris thinning and firm connection of a disorganized retina to BM. These findings may help elucidating the process of axial elongation in myopic eyes.

Decreasing myopic lacquer crack and widening parapapillary gamma zone: case report

Background

Myopic axial elongation may be due to an equatorial enlargement of Bruch’s membrane (BM), leading to a prolate eye shape and increasing strain with BM and the retinal pigment epithelium (RPE) layer at the posterior pole. The increased BM strain may cause an enlargement of Bruch’s membrane opening (BMO) of the optic nerve head, with the subsequent development and enlargement of parapapillary gamma zone as BM-free parapapillary zone. The increased strain within BM and RPE may also cause lacquer cracks (LCs) as linear breaks in the RPE and / or BM. Studies suggested that a more marked gamma zone enlargement is associated with lower prevalence of LCs or macular BM defects. Here report on the disappearance of a LC during a 10-year follow-up of a highly myopic eye, concurrent with a marked increase in gamma zone.

Case presentation

A 56-year-old woman showed in her right eye (axial length measured 30.69 mm) a LC, vertically oval optic disc, and parapapillary gamma zone in 2001. When re-examined in 2006, gamma zone had enlarged, while the LC was no longer detectable. In 2011, the LC was not visible neither upon ophthalmoscopy and or upon optical coherence tomography (OCT), while gamma zone had further enlarged. The gamma zone enlargement occurred in a direction perpendicular to the direction of the former LC.

Conclusions

The observation suggest that a LC can decrease in width, in temporal association with an enlargement of gamma zone. It fits with the notion that an enlargement of the BMO (i.e., enlarging gamma zone) may lead to a relaxation of the BM strain and subsequently to a decrease in the width of the LC.

Wide-field swept source optical coherence tomography evaluation of posterior segment changes in highly myopic eyes

BACKGROUND

To investigate the features in the posterior pole of highly myopic (HM) eyes using a wide-field high-resolution swept source optical coherence tomography (SS OCT).

METHODS

This observational cross-sectional study involved 262 eyes of 139 patients, who were diagnosed as HM and had consecutively been examined by SS OCT in the Ophthalmology Department of the Peking Union Medical College Hospital between March 2019 and December 2019. The characteristics of OCT images were documented and analyzed.

RESULTS

In our study, SS OCT could demonstrate the entire layer of the choroid and detect the sclera in all eyes. The mean subfoveal retinal/choroidal/scleral thickness were 204.84 ± 119.86 μm, 92.80 ± 75.78 μm and 394.734 ± 123.09 μm, respectively. 138 eyes (52.67%) had posterior precortical vitreous pocket. Myopic foveoschisis was detected in 110 eyes (41.98%), and significantly associated with the presence of posterior staphyloma. 36 eyes (13.74%) had DSM in our study, of which 8 eyes (22.22%) showed a round dome, 16 (44.44%) were horizontal oval-shaped, 9 (25%) were vertical oval-shaped and 3 (8.34%) were oblique oval-shaped. Both SFCT and SFST were inversely and significantly associated with age and refractive errors. Macular neovascularization was significantly correlated with intrascleral vessels. Different deformation of the sclera and posterior staphyloma were vividly identified on SS OCT images.

CONCLUSIONS

This study provided a relatively comprehensive picture of posterior pole in HM eyes. Such good visualization of ocular fundus provided by wide-field SS OCT could be useful for the therapy option, disease condition monitoring and pathogenesis investigation.

CLINICAL AND MORPHOLOGIC FEATURES OF POSTERIOR STAPHYLOMA EDGES BY ULTRA-WIDEFIELD IMAGING IN PATHOLOGIC MYOPIA

PURPOSE

To investigate morphologic features along posterior staphyloma edges in eyes with pathologic myopia using ultra-widefield optical coherence tomography imaging.

METHODS

Highly myopic patients (refractive error < -8 diopters or axial length ≥26.5 mm) were consecutively examined by prototype ultra-widefield optical coherence tomography with a scan width of 23 mm and depth of 5 mm. Staphyloma edges were assessed for scleral, choroidal, and retinal status, as well as measurements of angle size. Findings were correlated with pigmentary changes observed on Optos fundus photography, and multivariate logistic regression analyses were performed.

RESULTS

In 164 eyes diagnosed with posterior staphyloma by ultra-widefield optical coherence tomography, choroidal thinning and scleral protrusion were hallmark features of staphyloma edges, observed simultaneously in more than 95% of staphylomatous eyes. Outer neural retinal thinning was observed in 80 eyes (48.8%), whereas 15 eyes (9.1%) showed retinal pigment epithelium damage. The mean angle at the staphyloma edge was 23° ± 12.4° (range 8° to 77°). Larger angles were significant predictors of retinal thinning (adjusted odds ratio: 1.17, confidence interval: 1.09-1.25), and the staphyloma was detected by Optos pseudocolor fundus photography (adjusted odds ratio: 1.08, confidence interval: 1.02-1.15).

CONCLUSION

These morphologic findings may provide a basis for exploring the natural evolution of posterior staphyloma as part of the development of pathologic myopia.

Dome-Shaped Macula versus Ridge-Shaped Macula Eyes in High Myopia Based on the 12-line Radial Optical Coherence Tomography Scan Pattern. Differences in Clinical Features

PURPOSE

To study clinical features in patients with ridge-shaped macula (RSM) compared with those with dome-shaped macula (DSM) having been previously classified by the number of swept-source optical coherence tomography (SS-OCT) radial scans affected.

METHODS

Retrospective observational study including 49 highly myopic eyes from 31 patients who underwent SS-OCT. DSM eyes were defined as those that showed a complete round inward convexity in all their axes, presenting an inward convexity ≥50 µm in the 12-line radial OCT scans. Eyes that did not meet this criterion and had at least one flat radial scan were grouped into the RSM group, defined as a macular inward convexity in some meridians across the fovea, whereas the opposite perpendicularly oriented meridians were flat. Age, spherical equivalent, axial length (AL), and best-corrected visual acuity (BCVA) were collected. Height of the bulge, scleral and choroidal thicknesses, Bruch´s membrane defects, and presence of perforating scleral vessels were recorded.

RESULTS

Thirty-seven (75.5%) eyes were classified into the RSM group and 12 (24.5%) into the DSM group. Twenty-six (53.0%) eyes showed macular elevation only in the horizontal direction. Mean AL showed statistically significant differences (28.8 ± 2.7 vs. 30.5 ± 1.5 mm in the RMS vs. DSM group, respectively) and the presence of Bruch´s membrane defects was more frequently seen in DSM (p < 0.001). Mean age, spherical equivalent, BCVA, height of the inward convexity, retinal foveal thickness, foveal scleral thickness, subfoveal choroidal thickness, and the presence of perforating scleral vessels did not show significant differences between groups.

CONCLUSION

This study shows the reliability of using the 12 equal radial OCT scans as an objective method to define and differentiate DSM versus RSM. Patients with RSM showed differences in AL compared with those with DSM, being longer in DSM, and regarding the presence of Bruch´s membrane defects, being more common in DSM. This may contribute to identifying those patients that, in daily clinical practice, have a higher risk of developing complications due to their myopia.

Continued Increase of Axial Length and Its Risk Factors in Adults With High Myopia

Importance

Pathologic myopia due to an excessive increase of axial length is associated with severe visual impairments. Systematic analyses to determine the rate of and the risk factors associated with the axial elongation in adults with high myopia based on long-term follow-up of a large population are needed.

Objective

To determine the risk factors associated with axial elongation in adults with high myopia.

Design, Setting, and Participants

This cohort study used the medical records of 43 201 patient visits in a single-hospital database that were collected from January 3, 2011, to December 28, 2018. A total of 15 745 medical records with the patients' sex, best-corrected visual acuity (BCVA), axial length, type of myopic maculopathy, and the presence or absence of choroidal neovascularization (CNV) were reviewed. Data were analyzed from April 3, 2019, to August 5, 2020.

Main Outcomes and Measures

Changes in the axial length at each examination were calculated. The significance of the associations between the annual increase of the axial length and age, sex, baseline axial length, types of myopic maculopathy, and a history of CNV was determined. Generalized linear mixed models were used to evaluate the strength of the risk factors associated with an increase of the axial length in high myopia.

Results

Among 1877 patients with 9161 visits included in the analysis, the mean (SD) age was 62.10 (12.92) years, and 1357 (72.30%) were women. The mean (SD) axial length was 29.66 (2.20) mm with a mean (SD) growth rate of 0.05 (0.24) mm/y. Among the 9161 visits, 7096 eyes (77.46%) had myopic maculopathy and 2477 eyes (27.04%) had CNV. The odds ratio for inducing a severe elongation of the axial length was 1.46 (95% CI, 1.38-1.55) for female sex, 0.44 (95% CI, 0.35-0.56) to 0.63 (95% CI, 13 0.50-0.78) for older than 40 years, 1.33 (95% CI, 1.15-1.54) for BCVA of less than 20/400, 1.67 (95% CI, 1.54-1.81) to 2.67 (95% CI, 2.46-2.88) for baseline axial length of 28.15 mm or greater, 1.06 (95% CI, 0.96-1.17) to 1.39 (95% CI, 1.24-1.55) for the presence of maculopathy, and 1.37 (95% CI, 1.29-1.47) for prior CNV.

Conclusions and Relevance

This cohort study found continuing axial elongation in adults with high myopia. The risk factors for elongation do not appear to be modifiable, so prevention of myopia may be the best approach to reduce the incidence of pathologic myopia and its complications in the future.

Association between the posterior ocular contour pattern and progression of myopia in children: A prospective study based on OCT imaging

PURPOSE

This study aims to reveal the relationship between the posterior ocular contour and the subsequent progression of myopia in children.

METHODS

Children aged 8-12 years with myopia received baseline measurements and were instructed to wear their glasses every day and return for a follow-up visit after one year. Axial length and other ocular parameters were measured using a noncontact biometer. The contour of the posterior eye was calculated and analysed based on images from spectral domain optical coherence tomography (SD-OCT). Univariate and multivariate linear regression models were created to analyse the relationship between the contour of the posterior eye and the progression of myopia.

RESULTS

Baseline posterior ocular contour measurements correlated with baseline axial length and spherical equivalent refraction (SER) (all p < 0.05). Eyes that were more myopic tended to have a more prolate posterior ocular contour. Although the baseline contour of the retinal pigment epithelium (RPE) and chorioscleral interface (CSI) showed no significant relationship with the progression of myopia (all p > 0.05), interestingly, when the baseline contour of the RPE was more prolate than that of the CSI, the axial length increased during the following year (R²  = 0.62; p < 0.01). The multivariate model, when adjusted for other variables, further validated the independent role of this variable.

CONCLUSIONS

The difference between the RPE and CSI contours correlated with the subsequent progression of myopia in children. This finding can help inform clinicians regarding the management of children at the onset of myopia and potentially provide an avenue for experimental research on the mechanism of myopia development.

Choroidal shift in myopic eyes in the 10-year follow-up Beijing eye study

The aim of the study was to assess longitudinal changes in the spatial relationship of the choroidal vasculature to retinal vasculature in myopic eyes. In the population-based longitudinal Beijing Eye Study in 2001/2011, we examined all highly myopic eyes with assessable fundus photographs and a randomized group of non-highly myopic. Using fundus photographs, we qualitatively assessed changes in the location of major choroidal vessels in relationship to retinal vessels. The study consisted of 85 highly myopic eyes (58 participants;age:64.8 ± 9.4 years) and 85 randomly selected non-highly myopic eyes. A choroidal shift in relationship to the retinal vessels was detected more often in the highly myopic group than the non-highly myopic group (47/85 (55%) vs 6/85 (7%); P < 0.001). In the highly myopic group, the choroidal vessel shift occurring on the disc-fovea line in 39 (44%) eyes, was similar to, or smaller than, the enlargement in gamma zone width in 26 (67%) eyes and in 11 (28%) eyes respectively. The choroidal vessel shift was larger (P = 0.002) in eyes without choroidal vessels in gamma zone than in eyes with large choroidal vessels in gamma zone. In 14 (17%) eyes, a localized centrifugal choroidal shift was observed in association with an increase in the stage of myopic maculopathy. The results suggest that highly myopic eyes show a change in the position of large choroidal vessels in relationship to retinal vessels, in association with development or enlargement of gamma zone and an increase in the stage of myopic maculopathy.

Intravitreal application of epidermal growth factor in non-exudative age-related macular degeneration

PURPOSE

To assess the safety of intravitreally applied epidermal growth factor (EGF).

METHODS

The clinical interventional, prospective, single-centre, case series study included patients with age-related macular degeneration-related geographic atrophy (GA), in whom the eye with the worse best-corrected visual acuity (BCVA) underwent a single, or repeated, intravitreal injection of EGF (0.75 µg in 50 µL). At baseline and afterwards, the eyes underwent ophthalmological examinations.

RESULTS

The study included seven patients (mean age:70.0±12.2 years (range: 54-86 years), with five patients receiving a single injection and two patients receiving two intravitreal injections in an interval of 4 weeks. Mean duration of follow-up was 97±97 days (median:35 days; range: 7-240 days). Mean BCVA was lower at baseline than at study end (1.41±0.44 logMAR vs 0.97±0.12 logMAR; p=0.03). Mean size of the GA lesions did not differ significantly between baseline and study end (29 212±22 887 pixels vs 29 300±22 905 pixels; p=0.59) nor did the mean perimetric mean defect (-10.3±5.9 dB vs 12.0±8.8 dB; p=0.35) or the electroretinographical b-wave amplitude (44.53±31.7 µV vs 64.5±25.5 µV; p=0.12). After a second injection 4 weeks after the first injection, one of two patients developed a cystoid macular oedema in association with an induced incomplete posterior vitreous detachment. It persisted for 3 weeks. Visual acuity in this eye improved from 1.0 logMAR at baseline to 0.80 logMAR at study end.

CONCLUSIONS

Except for one eye with temporary, self-resolving cystoid macular oedema, single and repeated intravitreal applications of EGF (0.75 µg) in patients with GA did not lead to intraocular inflammations or any observed intraocular side effect.

TRIAL REGISTRATION NUMBER

ISRCTN12733334.

PROGRESSION OF MYOPIC MACULOPATHY IN CHINESE CHILDREN WITH HIGH MYOPIA: A Long-Term Follow-Up Study

PURPOSE

To investigate the progression of myopic maculopathy and associated factors in highly myopic Chinese children.

METHODS

In this retrospective observational case series, biometric fundus features were morphometrically measured on photographs. Myopic maculopathy was defined as recommended by the Meta-analysis of Pathologic Myopia Study Group.

RESULTS

The study included 274 children (mean age: 11.7 ± 2.5 years; mean refractive error: -7.66 ± 1.87 diopters [D]) with a mean follow-up of 4.9 ± 1.2 years. Myopic maculopathy progression was detected in 52 eyes (18.9%; 95% confidence interval [CI]: 14.3-23.7%). In multivariable analysis, myopic maculopathy progression was associated with a decrease in refractive error (odds ratio [OR]: 0.72; 95% CI: 0.56-0.92; P < 0.001) (i.e., higher myopization) and enlargement of parapapillary gamma zone (OR: 7.68; 95% CI: 1.63-36.2; P = 0.002). Incident peripapillary diffuse choroidal atrophy, noted in 47 of 236 eyes (20.0%; 95% CI: 14.8-25.2%), was correlated with a decrease in refractive error (OR: 0.70; 95% CI: 0.54-0.92; P = 0.009) (i.e., higher myopization) and greater gamma zone enlargement (OR: 8.28; 95% CI: 1.33-51.7; P = 0.02).

CONCLUSION

Myopia in schoolchildren may have a considerable risk of progressing to myopic maculopathy. Enlargement of parapapillary gamma zone was a main independent risk factor.

Location of Parapapillary Gamma Zone and Vertical Fovea Location. The Beijing Eye Study 2011

Purpose

To assess the spatial relationship between the locations of the parapapillary gamma zone and the fovea.

Methods

In a non-glaucomatous subgroup of the population-based Beijing Eye Study population, we measured the mean angle between the optic disc–fovea line and the horizontal (disc–fovea angle), the vertical distance of the fovea from the horizontal through the optic disc center (fovea vertical distance), and the location and width of the widest part of parapapillary gamma zone.

Results

The study included 203 individuals (203 eyes; mean axial length, 24.4 ± 1.5 mm; range, 22.03–28.87 mm). The widest gamma zone part was located most often temporal horizontally (51.7%), then inferiorly (43.8%), superiorly (2.5%), and nasally (2.0%). The disc–fovea angle (mean, 7.50° ± 4.00°; range, –6.30° to –23.25°) was significantly higher (P = 0.003; i.e., fovea located more inferiorly) in eyes with the widest gamma zone inferiorly (8.46° ± 4.37°) than in eyes with the widest gamma zone temporally (6.71° ± 3.46°) and in eyes with the widest gamma zone temporally, superiorly, or nasally combined (6.75° ± 3.53°; P = 0.003). The fovea vertical distance (mean, 0.65 ± 0.33 mm; range, –0.20 to 1.67 mm) was longer (P = 0.001; i.e., fovea located more inferiorly) in eyes with the widest gamma zone inferiorly (0.73 ± 0.33 mm) than in eyes with the widest gamma zone temporally (0.58 ± 0.30 mm) and in eyes with a temporal, superior, or nasal gamma zone combined (0.58 ± 0.31 mm; P = 0.001). The fovea vertical distance increased (multivariate analysis) with the widest gamma zone location inferiorly (β = 0.25; P = 0.001) and wider width of the gamma zone (β = 0.19; P = 0.01).

Conclusions

An inferior fovea location is associated with a wider inferior gamma zone and vice versa, supporting the notion of an inferior shifting of Bruch's membrane as the cause for an inferior gamma zone.

IMI Pathologic Myopia

Pathologic myopia is a major cause of visual impairment worldwide. Pathologic myopia is distinctly different from high myopia. High myopia is a high degree of myopic refractive error, whereas pathologic myopia is defined by a presence of typical complications in the fundus (posterior staphyloma or myopic maculopathy equal to or more serious than diffuse choroidal atrophy). Pathologic myopia often occurs in eyes with high myopia, however its complications especially posterior staphyloma can also occur in eyes without high myopia.

Owing to a recent advance in ocular imaging, an objective and accurate diagnosis of pathologic myopia has become possible. Especially, optical coherence tomography has revealed novel lesions like dome-shaped macula and myopic traction maculopathy. Wide-field optical coherence tomography has succeeded in visualizing the entire extent of large staphylomas. The effectiveness of new therapies for complications have been shown, such as anti-VEGF therapies for myopic macular neovascularization and vitreoretinal surgery for myopic traction maculopathy.

Myopia, especially childhood myopia, has been increasing rapidly in the world. In parallel with an increase in myopia, the prevalence of high myopia has also been increasing. However, it remains unclear whether or not pathologic myopia will increase in parallel with an increase of myopia itself. In addition, it has remained unclear whether genes responsible for pathologic myopia are the same as those for myopia in general, or whether pathologic myopia is genetically different from other myopia.

CLINICAL FEATURES OF PATCHY CHORIORETINAL ATROPHY IN PATHOLOGIC MYOPIA

PURPOSE

To reveal clinical features of patchy atrophy in pathologic myopia and investigate the status of the Bruch membrane and retinal pigment epithelium by swept-source optical coherence tomography.

METHODS

This study reviewed highly myopic patients who visited the high myopia clinic between January 2015 and February 2018. Wide-field photographs and wide-field fundus autofluorescence fundus images were used as the primary method for identifying PAs, and swept-source optical coherence tomography images were used for investigating the retinochoroid status of PAs.

RESULTS

Four hundred fifty-six PAs were detected in 137 eyes (118 patients). Patchy atrophys were located most often in the macular area (28.3%), followed by the inferior (25.9%), temporal (18.9%), nasal (14.5%), and superior (12.5%) region. All 210, PAs which had been fully or partially scanned by swept-source optical coherence tomography, showed a retinal pigment epithelium defect, and 174 (82.9%) PAs showed a Bruch membrane defect on the available scans. In 101 (82.8%) of 122 PAs with clearly detectable borders of the retinal pigment epithelium and Bruch membrane defect, the Bruch membrane defects were smaller than the retinal pigment epithelium defects. A dome-shape inward bulging of the sclera was observed in 10 PAs.

CONCLUSION

These morphological findings may provide a basis for exploring the biomechanical etiology of the PAs as part of the development of pathologic myopia.