Scleral thickness in highly myopic eyes measured by enhanced depth imaging optical coherence tomography

Characteristics of myelinated retinal nerve fibres in associated straatsma syndrome

PURPOSE

To study cases diagnosed of myelinated retinal nerve fibres (MRNF) continuous with the optic disc and describe the plausible pathogenic mechanism for the ocular features in Straatsma syndrome.

METHODS

This retrospective observational study includes clinically diagnosed MRNF cases. MRNF, myopia, and amblyopia defined Straatsma syndrome. MRNF were classified into three types based on location: type 1 in the superior retina, type 2 in the superior and inferior retina, and type 3 in the inferior retina. MRNF size was measured on Optomap® (Optos, Daytona, UK) images and posterior staphyloma location was noted. Demographics and best-corrected refractive error in logMAR units was recorded. Descriptive statistics and Spearman's corelation test were used to analyse MRNF size's relationship to refractive error and logMAR visual acuity.

RESULTS

The study included a total of 19 MRNF eyes from 18 patients. Seventeen (89%) eyes had Straatsma syndrome. Median age was 23.50 [range: 4-75] years. One (6%) patient exhibited bilateral presentation. The median logMAR visual acuity was 0.4 log units (interquartile range: 0.18-1.20) and mean refractive error was -7.21 ± 5.32. Type 2 MRNF (n = 14,74%) was the commonest. Average MRNF size was 34.37 ± 40.73 sq.mm. Posterior staphyloma was noted in 17 eyes, all in close MRNF association. Significant positive corelation was noted between logMAR visual acuity and MRNF size (r = 0.5, p = 0.028).

CONCLUSION

Large size MRNF corelated with poor visual acuity in the study. The paper explains the possible pathogenetic mechanisms for the ocular findings seen in MRNF.

Axial length and pharmacologic pupillary dilation in highly myopic patients

PURPOSE

To determine how high myopia impacts pharmacological pupillary dilation, and to evaluate the relationship between the extent of pharmacologic pupillary dilation and axial length.

METHODS

Patients were grouped into high myopes, defined as one or both eyes having a refractive error greater than - 6 diopters, and controls (between - 2 and + 2 diopters). Dilation was achieved with 1 drop each of tropicamide 1% and phenylephrine 2.5%. Pupil size was measured at full and dim light prior to dilation, then 15 and 30 min after dilation. Biometry was measured for each patient. Statistical analyses were performed using the Mann-Whitney-Wilcoxon tests, two-sample Welch's t-tests, and linear mixed effect models and generalized estimating equations models accounting for inter-eye correlation.

RESULTS

Forty patients (20 high myopes and 20 controls, 80 eyes total) participated in the study. High myopes had larger pupils at baseline and achieved significantly greater pupillary size (7.08 mm, 95% CI: 6.97 to 7.19 mm) than controls (6.23 mm, 95% CI: 5.94 to 6.52 mm) after 30 min of dilation (P < .0005). Fully dilated pupil size at 30 min was significantly correlated with both refractive error (r =  - 0.57, P < .0005) and axial length (r = 0.47, P < .0005). Generalized estimating equations and linear mixed effect models identified other predictive variables of pupil size after dilation including age and white-to-white diameter.

CONCLUSIONS

Highly myopic patients dilate to a larger pupillary size compared to other patients. Predicting dilation based on extent of myopia could facilitate intraocular surgery planning and reduce clinic wait times for myopic patients.

PRESERFLO MicroShunt in Severe Myopia: A Case Report and Review of the Literature

The PRESERFLO™ MicroShunt (MP; Santen Inc., Osaka, Japan) is a minimally invasive bleb surgery (MIBS) manufactured to treat primary open-angle glaucoma (POAG), with lower postoperative adverse effects than with conventional filtering surgeries. We describe here the case study of a 58-year-old woman who presented with bilateral severe myopia with bilateral advanced POAG and unreached target pressure under quadritherapy, who was successfully managed by PM surgery. A review of the literature completes our observation. At presentation, the patient had a spherical equivalent of - 7.50 RE and - 7.75 LE with an IOP of 22 mmHg right and left eye (RLE) under quadritherapy, and with severe bilateral visual field loss, including scotomas within the central 5°. The patient presented with systemic hypertension treated with an antihypertensive drug. Two selective laser trabeculoplasties (SLT), performed 3 months apart, were first tried on the LE, without any change in IOP at 2 months. After considering the high risk of postoperative complications, a PM operation was proposed, with a targeted IOP in the mid-fifteens RLE. The patient's eyes underwent PM surgery with mitomycin C (MMC) MMC0.2 mg/mL for 3 minutes without any complications. The LE required 2 consecutive needlings with 1 mL MMC0.2 mg/mL. At 24 months after surgery, the two eyes gave successful results without the need for any additional medical therapy, and with well-functioning conjunctival blebs. The PM was an effective alternative to the gold standard trabeculectomy in our severely myopic patient. A comparative study between conventional filtering operations and this MIBS in highly myopic patients would confirm our observation.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

CLINICAL TRIAL REGISTRATION

The study was registered at www.

CLINICALTRIALS

gov (Reg. No. NCT03446300).

Intraocular pressure-lowering effects of ripasudil on open-angle glaucoma in eyes with high myopia and pathological myopia

The aim is to study the intraocular pressure (IOP)-lowering effects of additional administration of ripasudil in open-angle glaucoma (OAG) patients including high myopia (HM) and pathological myopia (PM). Study design is retrospective cohort study. We assessed the changes in the mean IOP between the HM eyes (axial length ≧ 26.5 mm 33 eyes) and the non-HM eyes (axial length < 26.5 mm 29 eyes) at 4 and 12 weeks from baseline. We also assessed the IOP changes between the PM eyes (21 eyes) and the non-PM eyes (41 eyes). The significant IOP reduction by the ripasudil administration was observed at 4 weeks in the non-HM eyes and at 12 weeks in HM and non-HM eyes. And the IOP reduction in the HM eyes was significantly less than the non-HM eyes at 4 and 12 weeks. IOP reduction by ripasudil had statistically significant association with the baseline IOP and presence of PM. Furthermore, significant IOP reduction by the ripasudil administration was observed at 4 and 12 weeks in the non-PM eyes, but not in the PM eyes. The additional administration of ripasudil was effective in the HM eyes, but less than non-HM eyes. And the PM may negatively contribute to reducing the IOP by ripasudil.

Changes in Expression in BMP2 and Two Closely Related Genes in Guinea Pig Retinal Pigment Epithelium during Induction and Recovery from Myopia

PURPOSE

We previously reported differential gene expression of the bone morphogenetic protein 2 (Bmp2) in guinea pig retinal pigment epithelium (RPE) after 1 day of hyperopic defocus, imposed with a negative contact lens (CLs). The study reported here sought to obtain insights into the temporal profiles of gene expression changes in Bmp2, as well as those of two closely related genes, the inhibitor of DNA binding 3 (Id3) and Noggin (Nog), both during myopia induction and when the CL treatment was terminated to allow recovery from induced myopia.

METHODS

To induce myopia, 2-week-old pigmented guinea pigs (New Zealand strain, n = 8) wore monocular -10 diopter (D) rigid gas-permeable (RGP) CLs for one week, while the other eye served as a control. Ocular measurements were made at baseline, 3 days, and 7 days after the initiation of CL wear, with treatment then being terminated and additional measurements being made after a further 3 days, 1 week, and 2 weeks. Spherical equivalent refractive errors (SERs), axial length (AL), choroidal thickness (ChT), and scleral thickness (ScT) data were collected using retinoscopy, optical biometry (Lenstar), and spectral domain optical coherence tomography (SD-OCT), respectively. RPE samples were collected from both eyes of the guinea pigs after either 1 day or 1 week of CL wear or 1 day or 2 weeks after its termination, and RNA was subsequently isolated and subjected to quantitative real-time PCR (qRT-PCR) analyses, targeting the Bmp2, Id3, and Nog genes.

RESULTS

Mean interocular differences (treated-control) in AL and SER were significantly different from baseline after 3 and 7 days of CL wear, consistent with induced myopia (p < 0.001 for all cases). Termination of CL wear resulted in the normalization (i.e., recovery) of the ALs and SERs of the treated eyes within 7 days, and the earlier significant ChT thinning with CL wear (p = 0004, day 7) was replaced by rapid thickening, which remained significant on day 7 (p = 0.009) but had normalized by day 14. The ChT changes were much smaller in magnitude than the AL changes in both phases. Interocular differences in the ScT showed no significant changes. The Bmp2 and Id3 genes were both significantly downregulated with CL wear, after 1 day (p = 0.012 and 0.016) and 7 days (p = 0.002 and 0.005), while Bmp2 gene expression increased and Nog gene expression decreased after the termination of CL wear, albeit transiently, which was significant on 1 day (p = 0.004 and 0.04) but not 2 weeks later. No change in Id3 gene expression was observed over the latter period. Conclusions: The above patterns of myopia induction and recovery validate this negative RGP-CL model as an alternative to traditional spectacle lens models for guinea pigs. The defocus-driven, sign-dependent changes in the expression of the Bmp2 gene in guinea pig RPE are consistent with observations in chicks and demonstrate the important role of BMP2 in eye growth regulation.

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.

Outcomes of standalone ab interno trabeculotomy in the treatment of open-angle glaucoma in eyes with high myopia

BACKGROUND

We retrospectively evaluate the long-term efficacy and safety of trabeculotomy glaucoma surgery in treating open-angle glaucoma (OAG) in eyes with high myopia (HM).

METHODS

This study included 20 eyes with HM (axial length ≥ 26.5 mm) and OAG; age, preoperative IOP (intraocular pressure), and sex-matched 20 non-HM eyes (axial length < 26.5 mm) served as controls. Each eye underwent standalone ab interno trabeculotomy using a Kahook dual blade. A follow-up examination was performed 36 months after surgery. The main outcome measure was the operative success rate (i.e., a ≥ 20% pre- to post-operative reduction in IOP with or without IOP-lowering medication). Kaplan-Meier analysis was employed as a measure of surgical success. The secondary outcome measures were postoperative IOP, the number of glaucoma medications, and postoperative complications.

RESULTS

IOP and the number of glaucoma medications were statistically significantly reduced at all postoperative follow-up examinations. The Kaplan-Meier analysis demonstrated that the probability of postoperative success at 36 months was 45% and 65% for HM and non-HM eyes, respectively. In the HM group, the presence of pathological myopia was statistically significant risk factor for surgical failure. No critical postoperative complications were detected.

CONCLUSIONS

In our study, the long-term efficacy of ab interno trabeculotomy in HM eyes with OAG was inferior to that in non-HM eyes with OAG. Our findings suggest that surgical indications for trabeculotomy in HM should be determined based on the presence of pathological myopia.

Does PLEX® Elite 9000 OCT Identify and Characterize Most Posterior Pole Lesions in Highly Myopic Patients?

High myopia (HM) is defined as an axial length (AL) ≥ 26 mm that may result in various pathologies that constitute pathologic myopia (PM). The PLEX^® Elite 9000 (Carl Zeiss AC, Jena, Germany) is a new swept-source optical coherence tomography (SS-OCT) underdevelopment that allows wider, deeper and more detailed posterior-segment visualization; it can acquire ultra-wide OCT angiography (OCTA) or new ultra-wide high-density scans in one image. We assessed the technology's ability to identify/characterize/quantify staphylomas and posterior pole lesions or image biomarkers in highly myopic Spanish patients and estimate the technology's potential to detect macular pathology. The instrument acquired 6 × 6 OCTA, 12 × 12 or 6 × 6 OCT cubes, and at least two high-definition spotlight single scans. A hundred consecutive patients (179 eyes; age, 51.4 ± 16.8 years; AL, 28.8 ± 2.33 mm) were recruited in one center for this prospective observational study. Six eyes were excluded because images were not acquired. The most common alterations were perforating scleral vessels (88.8%), classifiable staphyloma (68.7%), vascular folds (43%), extrafoveal retinoschisis (24%), dome-shaped macula (15.6%), and more uncommonly, scleral dehiscence (4.46%), intrachoroidal cavitation (3.35%), and macular pit (2.2%). The retinal thickness of these patients decreased, and the foveal avascular zone increased in the superficial plexus compared with normal eyes. SS-OCT is a novel potent tool that can detect most main posterior pole complications in PM and may provide us with a better understanding of the associated pathologies; some pathologies were identifiable only with this new kind of equipment, such as perforating scleral vessels, which seem to be the most common finding and not so frequently related to choroidal neovascularization, as previously reported.

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.

Ultraviolet A at levels experienced outdoors suppresses transforming growth factor-beta signaling and collagen production in human scleral fibroblasts

Previous studies have highlighted the importance of outdoor time in reducing the risk of myopia progression. Although ultraviolet A (UVA) radiation dominates in terms of energy with respect to the UV radiation reaching the Earth's surface, its effects on the exposed anterior sclera have not been well studied. This study was designed to investigate the UVA-induced biological effects at peak sunlight levels in human scleral fibroblasts (HSFs). Using next-generation sequencing (NGS), we analyzed the differentially expressed genes (DEGs) in UVA-treated and normal HSFs. Further, we then identified the functions and key regulators of the DEGs using bioinformatics analysis, and verified the effects of UVA on gene and protein expression in HSFs using real-time PCR, western blotting, and immunofluorescence imaging. The highest level of solar UVA (365 nm) was 3.4 ± 0.18 (mW/cm²). The results from the functional analysis of the DEGs were related to structural changes in the extracellular matrix (ECM) and protein metabolism. Transforming growth factor-β1 (TGF-β1) and Smad3 were predicted to be potential upstream regulators, associated with ECM organization. Exposure to a single wavelength of UVA (365 nm, 3 mW/cm²) for 1 h for 5 consecutive days induced the downregulation of the mRNA of ECM genes including COL1A1, COL3A1, COL5A1, VCAN and collagen I protein in HSF. UVA downregulated Smad3 protein and reduced TGF-β-induced collagen I protein production following UVA exposure in HSF. In conclusion, high UVA exposure reduces TGF-β signaling and collagen I production by modulating Smad levels in HSF. The effects of overexposure to high-intensity UVA on myopia control require further investigations.

Anterior scleral thickness in patients of central serous chorioretinopathy: A Case–control study

BACKGROUND

The aim of this study was to determine whether anterior scleral thickness (AST) varies significantly between patients with central serous chorioretinopathy (CSCR) versus normal individuals. To validate scleral thickness measurements by ultrasound biomicroscopy (UBM) vis a vis anterior segment optical coherence tomography (ASOCT).

METHODS

This case-control study analyzed 50 eyes of 50 patients with CSCR (cases) and compared it with that of 50 eyes of 50 age- and gender-matched controls. In cases, AST was measured at 1 mm and 2 mm temporal to the temporal scleral spur by ASOCT and UBM. In controls, AST was measured only by ASOCT. In all participants, posterior choroidal thickness (CT) was measured subfoveally, 1 mm nasal and 1 mm temporal to fovea by enhanced depth imaging optical coherence tomography.

RESULTS

The mean AST, as measured by ASOCT among cases and controls was 703.86 μm and 667.54 μm, respectively (P = 0.006). The mean AST by ASOCT and UBM in cases were 703.86 μm and 657.42 μm, respectively (P = 0.001). AST measurement by ASOCT and UBM showed a positive and statistically significant correlation (r = 0.431, P = 0.000). The mean CT among cases and controls was 443.56 μm and 373.88 μm, respectively (P = 0.000). We found a weak positive correlation (r = 0.11) in cases and weaker positive correlation in controls, between CT and AST measured by ASOCT.

CONCLUSIONS

Our findings suggest that AST varies significantly between patients with CSCR versus normal individuals. We found poor agreement of AST when measured by ASOCT and UBM.

Scleral melt and uveal prolapse following 23-gauge pars plana vitrectomy

Purpose

To report a case of uncontrolled juvenile open angle glaucoma (JOAG), with secondary high axial myopia who presented with scleral melting and uveal prolapse post pars plana-vitrectomy.

Observations

A 17-year-old male juvenile glaucoma patient, not known to have any systemic disease underwent a right eye 23-gauge-pars plana vitrectomy for retinal detachment repair. Three weeks following his surgery he presented complaining of tearing and photophobia in the operated eye in the absence of any ocular pain. Clinical exam revealed enlarged sclerotomy sites with localized conjunctival and episcleral injection, scleral thinning and uveal prolapse. Infectious and serologic work up were obtained to rule out an infectious etiology or underlying autoimmune disease. Patient was successfully managed with topical steroids and a donor scleral patch graft.

Conclusion and importance

This report addresses multiple risk factors for a devastating complication that may occur in predisposed patients, with primary or secondary axial myopia and a compromised sclera. This group of patients can be at risk of post-operative scleral melting and thinning and should be identified pre-operatively and monitored closely during their post-operative course.

The Anterior Segment Biometrics in High Myopia Eyes

INTRODUCTION

The aim of this study was to investigate and compare the anterior segment biometrics in high myopia and control groups.

METHODS

Thirty-four eyes of 34 high myopia patients and 42 eyes of 42 control subjects were included. Schlemm's canal (SC) area, trabecular meshwork (TM) thickness and length, scleral spur (SS) length, and anterior scleral thickness (AST) were measured using swept-source optical coherence tomography. Associations between SC area, TM thickness, TM length, SS length, and AST were also estimated.

RESULTS

SC area, TM thickness, and SS length were significantly associated with AST0 (AST at 0 mm from SS) in both high myopia and control groups. AST0 (702.61 ± 78.05 vs. 729.12 ± 95.87 μm, p = 0.085) and SS length (206.25 ± 52.25 vs. 212.09 ± 51.86 μm, p = 0.556) were not significantly different between high myopia and control groups, whereas SC area (6,622.68 ± 1,130.06 vs. 6,105.85 ± 1,297.84 μm2, p = 0.015) was significantly greater and TM thickness (96.15 ± 34.40 vs. 107.93 ± 29.97 μm, p = 0.048) was significantly thinner in high myopia group than in control group.

CONCLUSION

SC area and TM thickness were significantly associated with AST0, while AST0 and SS length were not significantly different between high myopia and control groups. The changes in SC and TM dimensions in high myopia eyes might be caused by factors other than AST0 and SS length.

Subfoveal scleral thickness is associated with peripheral retinal changes in high myopia in children and adolescents

BACKGROUND

This study aims to identify the risk factors in peripheral retinal changes (PRC) associated with high myopes among children and adolescents.

METHODS

This is a cross-sectional study on children and adolescents diagnosed with high myopia. The subjects involved underwent a series of ocular examinations, including the dilated fundus examination for PRC and the swept-source optical coherence tomography for foveal retinal, choroidal and scleral thickness measurement. Then, the variables were compared among the eyes with high risk, low risk, and no PRC. Spearman correlation was applied to evaluate the relationship between the parameters and the extent of PRC. Logistic regression was performed to identify the potential risk factors.

RESULTS

A total of 117 eyes from 117 subjects were recruited. The prevalence of PRC was 57.3% (67 eyes), while that of high-risk PRC was 22.2% (26 eyes). Significant differences were found in the mean subfoveal scleral thickness, spherical equivalent refraction, and axial length among the eyes with high-risk, low-risk, and no PRC (p < 0.01, p < 0.01, p = 0.048, respectively). Compared with spherical equivalent (r = 0.32, p < 0.01) and axial length (r = 0.18, p = 0.05), subfoveal scleral thickness exhibited higher correlation coefficient with PRC (r =  - 0.38, p < 0.01). Subfoveal scleral thickness and spherical equivalent refraction were identified as the independent risk factors for PRC and high-risk PRC.

CONCLUSION

It was demonstrated that there was a correlation between subfoveal scleral thickness and PRC. The eyes with thinner subfoveal scleral thickness carried a higher risk of PRC.

Investigation of Macular Structural and Microcirculatory Characteristics of Posterior Staphyloma in High Myopic Eyes by Swept Source Optical Coherence Tomography Angiography

Purpose: To investigate the characteristics of macular structures and microcirculation of posterior staphyloma (PS) and explored factors related to PS in eyes with high myopia.

Methods: There were 114 eyes of 82 patients in this study. Using 1:1 matching of the axial length of myopic eyes, patients were divided into no PS (NPS) and PS groups. Comprehensive ophthalmic examinations were performed on all patients. Structural parameters were acquired using swept source optical coherence tomography (SS-OCT). OCT angiography (OCTA) was used to measure the microcirculation parameters. Generalized estimated equation and linear correlation analysis were used for the statistical analysis.

Results: Patients with PS had a thinner retinal thickness (RT) and choroid thickness (CT) (all p < 0.05) in the measurement areas and a significantly lower subfoveal scleral thickness (SFST) (p < 0.001) than those without PS. Retinal deep vascular complex density (DVD) (all p < 0.05) and choriocapillaris perfusion area (CCPA) (all p < 0.001) were significantly lower in the measurement areas of the PS group than in those of the NPS group. There was no significant difference in the retinal superficial vascular density between the two groups. Generalized estimating equation indicated that SFST (B = 0.079, p = 0.001), parafoveal RT (B = −0.162, p = 0.041), foveal CT (B = 0.292, p = 0.013), parafoveal CT (B = −0.157, p = 0.023), foveal CCPA (B = 0.691, p = 0.003) and parafoveal CCPA (B = −0.026, p = 0.004) were significantly correlated with PS. Age (r = −0.323, p = 0.001), spherical equivalent refraction (SER) (r = 0.289, p = 0.004), subfoveal CT (r = 0.398, p < 0.001), foveal DVD (r = 0.346, p < 0.001), foveal CT (r = 0.429, p < 0.001), and foveal CCPA (r = 0.387, p < 0.001) were strongly correlated with SFST.

Conclusions: The macular structures and microcirculation in the PS group were different from those in the NPS group. SFST, CT, and CCPA were significantly correlated with PS. Lower SFST in PS was correlated with abnormalities of CT and microcirculation.

Application of Artificial Intelligence and Deep Learning for Choroid Segmentation in Myopia

PURPOSE

To investigate the correlation between choroidal thickness and myopia progression using a deep learning method.

METHODS

Two data sets, data set A and data set B, comprising of 123 optical coherence tomography (OCT) volumes, were collected to establish the model and verify its clinical utility. The proposed mask region-based convolutional neural network (R-CNN) model, trained with the pretrained weights from the Common Objects in Context database as well as the manually labeled OCT images from data set A, was used to automatically segment the choroid. To verify its clinical utility, the mask R-CNN model was tested with data set B, and the choroidal thickness estimated by the model was also used to explore its relationship with myopia.

RESULTS

Compared with the result of manual segmentation in data set B, the error of the automatic choroidal inner and outer boundary segmentation was 6.72 ± 2.12 and 13.75 ± 7.57 µm, respectively. The mean dice coefficient between the region segmented by automatic and manual methods was 93.87% ± 2.89%. The mean difference in choroidal thickness over the Early Treatment Diabetic Retinopathy Study zone between the two methods was 10.52 µm. Additionally, the choroidal thickness estimated using the proposed model was thinner in high-myopic eyes, and axial length was the most significant predictor.

CONCLUSIONS

The mask R-CNN model has excellent performance in choroidal segmentation and quantification. In addition, the choroid of high myopia is significantly thinner than that of nonhigh myopia.

TRANSLATIONAL RELEVANCE

This work lays the foundations for mask R-CNN models that could aid in the evaluation of more intricate changes occurring in chorioretinal diseases.

Visually guided chick ocular length and structural thickness variations assessed by swept-source optical coherence tomography

Chicks are an excellent model for studying myopia. To study the change of the ocular structures in chicks, ultrasound is mostly used. However, it suffers from limited spatial resolution. In this study, we investigated the axial length (AL) and the thickness of different ocular structures in chicks' eye undergoing visually induced changes using a swept-source optical coherence tomography (SS-OCT) system in vivo. Two groups of chicks wore a translucent plastic goggle (n = 6) over the right eye to induce form-deprivation myopia. Following 12 days of form deprivation, goggles were removed in one group of chicks (n = 3), and they were allowed to experience 5 days of unrestricted vision (recovery). Goggles remained in place for a total of 17 days for the remaining 3 chicks. A separate group of 3 chicks were untreated and served as normal control. Ocular dimensions were measured in control, myopic, and recovered eyes using an SS-OCT system. We found myopic chick eyes had significantly thicker AL, lens thickness (LT), anterior chamber depth (ACD), and vitreous chamber depth (VCD), but significantly thinner retina thickness (RT) and choroid thickness (ChT) compared to the control eyes. Following 5 days of recovery, the cornea thickness (CT), retina pigment epithelium thickness (RPET), and ChT were significantly thicker, while the ACD and LT became significantly thinner compared to that of myopic eyes. SS-OCT can serve as a promising tool to provide measurements of the entire ocular structures, for evaluating the change of thickness and depth of different ocular structures in chicks in vivo. The change of AL in the myopic and recovered chick eyes can be attributed to the thickness alterations of different ocular structures. Altogether, this work demonstrated the feasibility of SS-OCT in chick myopic research and exhibited new insights into the changes of ocular structures in chicks experiencing myopia after unrestricted vision recovery.

Effects of lumican expression on the apoptosis of scleral fibroblasts: In vivo and in vitro experiments

Lumican serves an important role in the maintenance of sclera biomechanical properties. However, whether lumican expression is altered in myopia and the mechanisms of action involved are unknown. In the present study, the expression of lumican in cultured scleral fibroblasts and in the scleral tissue of a rat model of form-deprivation myopia was assessed. It was confirmed that diopter was decreased, whereas axial length was increased in modeled eyes relative to normal control eyes, indicating that the model of myopia was successfully established. These pathologic changes were accompanied by the upregulation of lumican and tissue inhibitor of metalloproteinases (TIMP)-2, as well as the downregulation of matrix metalloproteinase (MMP)-2 and MMP-14. The same trends in TIMP-2, MMP-2 and MMP-14 expression were observed when lumican was overexpressed in cultured scleral fibroblasts. Additionally, cell proliferation decreased whereas apoptosis increased compared with those of control cells. Inhibiting lumican expression had no effect on cell proliferation or apoptosis, but stimulated the expression of MMP-2 and MMP-14 while decreasing that of TIMP-2. The results suggested that lumican overexpression contributed to myopia by promoting apoptosis in scleral fibroblasts via the modulation of TIMP-2, MMP-2 and MMP-14 expression.

Long-term progression of myopic maculopathy in degenerative myopia as imaged by SD-OCT and IR imaging

CLINICAL RELEVANCE

Clinicians can benefit from developing an understanding of the natural disease progression of myopic maculopathy in degenerative myopia using optical coherence tomography (OCT).

BACKGROUND

The prevalence of high myopia is constantly increasing. In this work, infrared imaging and OCT is used to study the natural course of the disease.

METHODS

This is a retrospective longitudinal study. Medical records of 72 patients with high myopia (< 6.00 D) and a minimum five-year follow-up period were analysed. Collected data on all enrolled patients included demographic characteristics and medical history, as well as recordings on best-corrected visual acuity, slitlamp examination, OCT, and fluorescein angiography in cases of suspected myopic choroidal neovascularisation. Images were independently marked by two graders.

RESULTS

The mean age of patients was 54.6 ± 14.4 years (59.72% female) with baseline logMAR best-corrected visual acuity of 0.22 ± 0.28. At baseline examination, 70.83% of the study group showed signs of maculopathy and 62.5% diffuse or patchy atrophy. During follow-up, 22.2% of patients with any type of atrophy showed enlarged affected areas. Two patients with baseline lacquer cracks developed new lesions. There was a weak correlation between patient age and maculopathy progression (r = 0.233; p = 0.03). While central retinal thickness was not associated with maculopathy progression (p = 0.203), a moderate correlation was found between choroidal thickness and maculopathy progression (r = -0.516; p < 0.001).

CONCLUSION

Lesion characteristics in myopic degeneration have been elucidated, taking advantage of the ongoing technological advances in retinal imaging. The understanding of disease patterns and progression is essential for appropriate management of patients, while discovering biomarkers which lead to choroidal neovascularisation development is of urgent importance to establish international diagnostic criteria and treatment protocols.

Retinal applications of swept source optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA)

The advent of optical coherence tomography (OCT) revolutionized both clinical assessment and research of vitreoretinal conditions. Since then, extraordinary advances have been made in this imaging technology, including the relatively recent development of swept-source OCT (SS-OCT). SS-OCT enables a fast scan rate and utilizes a tunable swept laser, thus enabling the incorporation of longer wavelengths than conventional spectral-domain devices. These features enable imaging of larger areas with reduced motion artifact, and a better visualization of the choroidal vasculature, respectively. Building on the principles of OCT, swept-source OCT has also been applied to OCT angiography (SS-OCTA), thus enabling a non-invasive in depth-resolved imaging of the retinal and choroidal microvasculature. Despite their advantages, the widespread use of SS-OCT and SS-OCTA remains relatively limited. In this review, we summarize the technical details, advantages and limitations of SS-OCT and SS-OCTA, with a particular emphasis on their relevance for the study of retinal conditions. Additionally, we comprehensively review relevant studies performed to date to the study of retinal health and disease, and highlight current gaps in knowledge and opportunities to take advantage of swept source technology to improve our current understanding of many medical and surgical chorioretinal conditions. We anticipate that SS-OCT and SS-OCTA will continue to evolve rapidly, contributing to a paradigm shift to more widespread adoption of new imaging technology to clinical practice.

Quantitative OCT angiography of the retinal microvasculature and choriocapillaris in highly myopic eyes with myopic macular degeneration

PURPOSE

To quantify retinal and choriocapillaris (CC) microvasculature in highly myopic (HM) eyes with myopic macular degeneration (MMD) using swept-source optical coherence tomography angiography (SS-OCTA).

METHODS

162 HM eyes (spherical equivalent ≤ -6.0 dioptres or axial length (AL) ≥26.5 mm) from 98 participants were enrolled, including 60 eyes (37.0%) with tessellated fundus, 54 eyes (33.3%) with peripapillary diffuse chorioretinal atrophy (PDCA), 27 eyes (16.7%) with macular diffuse chorioretinal atrophy (MDCA) and 21 eyes (13.0%) with patchy or macular atrophy. PLEX Elite 9000 SS-OCTA was performed to obtain perfusion densities (PD) of the superficial and deep retinal capillary plexus, and CC signal voids (number, area and density).

RESULTS

Retinal PD decreased with increasing severity of MMD. Multivariable analysis showed that after adjustment of age and other factors, retinal PD decreased significantly in eyes with longer AL (β≤-0.51, p<0.001) and with an MMD severity of MDCA or worse (β≤-1.63, p<0.001). Reduced retinal PD were significantly associated with worse vision (β≤-0.01, p≤0.04). In terms of CC signal voids, multivariable analysis showed that longer AL (p<0.001), but not MMD severity (p≥0.12) was significantly associated with CC signal void changes in the earliest stage of MMD.

CONCLUSION

We demonstrate significant OCTA alterations in the retina and CC in HM eyes with varying severities of MMD. In eyes with early-stage PDCA, lower retinal PD and more extensive CC signal voids are predominantly associated with increasing AL. In contrast, in eyes with MDCA or worse, MMD itself was associated with sparser retinal and CC circulation.

Anterior Scleral Thickness in Myopic Eyes and Its Association with Ocular Parameters

PURPOSE

This study was designed to determine whether the anterior scleral thickness is affected by axial elongation and to investigate the association between anterior scleral thickness and various ocular parameters in myopic eyes.

METHODS

This cross-sectional study included 79 healthy myopic participants. Anterior scleral thickness was measured in 8 meridians (superior-nasal, superior, superior-temporal, temporal [T], inferior-temporal, inferior [I], inferior-nasal, and nasal [N]) using anterior segment optical coherence tomography. Bruch's membrane opening (BMO) area, width of β-parapapillary atrophy with and without Bruch's membrane (PPA+BM and PPA-BM), and the global peripapillary and subfoveal choroidal thickness were additionally measured. Age- and sex-adjusted partial correlation analysis and linear regression analysis were performed to examine the effects of axial length and various ocular parameters on anterior scleral thickness in myopic eyes.

RESULTS

The mean age of the included participants was 27.03 ± 2.70 years. Overall, the anterior scleral thickness varied topographically according to the meridians and distance from the scleral spur. In the partial correlation analysis controlled for the effect of age and sex, increasing axial length was related to anterior scleral thinning at several measurement points along the T, I, and N meridians. Among the several ocular parameters, multivariate linear regression analysis with age, sex, and axial length as covariates revealed that central corneal thickness, intraocular pressure, and BMO area were significantly associated with anterior scleral thickness.

CONCLUSION

In conclusion, there was a close relationship between the anterior scleral thickness and several ocular parameters in myopic eyes. These features should be taken into consideration when managing myopia, and our results might have important implications for understanding the pathogenesis of scleral changes during axial elongation.

Anterior Sclera Undergoes Thinning with Increasing Degree of Myopia

Purpose

Considering that ocular expansion is associated with scleral thinning, this study investigated variation in scleral thickness (anterior scleral thickness [AST] and posterior scleral thickness [PST]) in different meridians across emmetropes and a wide range of myopes.

Methods

A total of 95 participants (mean age, 24 ± 4 years) including emmetropes (spherical equivalent refractive error, ±0.75 diopters [D]; n = 20) and myopes (-1.00 to -27.25 D; n = 75) underwent ocular imaging with swept-source optical coherence tomography. All the images were analyzed using semiautomated custom-designed software to determine scleral thickness in 1-mm intervals. AST was estimated from limbus to 5 mm (n = 95), and PST from fovea to 5 mm (n = 25; high myopes only) along the horizontal and vertical meridian.

Results

The median spherical equivalent refractive error and axial length were -4.25 D (IQR, -12.50 to -1.00 D) and 25 mm (IQR, 23.72-28.35 mm), respectively. The anterior sclera was thinnest in the superior and thickest in the inferior region (475.3 ± 19.0 vs. 605.9 ± 18.6 µm; P < 0.001). The inferior AST alone decreased significantly with increasing magnitude of myopia (r = 0.27; P = 0.008). There were no differences in AST between nasal and temporal meridians (583.24 ± 15.00 vs. 587.09 ± 27.00 µm; P > 0.05). The mean subfoveal PST for the subset of high myopes was 251.7 ± 12.0 µm which was thinner than mean AST along all the meridians by more than 45%. The averaged scleral thickness peripheral to fovea (1-5 mm) was similar along different meridians (P > 0.05).

Conclusions

The relative significant thinning of the anterior sclera along the inferior meridian with increasing degree of myopia compared with the other three meridians indicates the potential role of AST, especially in the inferior meridian, to act as a marker for myopia progression.

CHARACTERIZATION OF THE CHOROIDAL VASCULATURE IN MYOPIC MACULOPATHY WITH OPTICAL COHERENCE TOMOGRAPHIC ANGIOGRAPHY

PURPOSE

To characterize the choriocapillaris (CC) in highly myopic eyes with myopic maculopathy, using optical coherence tomographic angiography.

METHODS

Prospective, clinic-based study of 42 eyes of 38 patients with high myopia (≤-6 diopters and axial length ≥26.5 mm). Myopic maculopathy was graded from fundus photographs according to the Meta-Analysis for Pathologic Myopia classification. Macular 3 × 3 mm en face optical coherence tomographic angiographic images were obtained with swept-source optical coherence tomographic angiography and graded for CC flow impairment as follows: 1) intact CC, 2) focal (<1 mm), and 3) extensive (>1 mm).

RESULTS

Of the 42 eyes, 17 (39.5%) had tessellated fundus, 20 (46.5%) had diffuse, and 6 (14.0%) had patchy atrophy. Choriocapillaris flow impairment was observed in all eyes with diffuse and patchy atrophy. Even in eyes with tessellated fundus only, CC signal voids were seen in 3 eyes (17.6%). With increasingly severe myopic maculopathy, the pattern of CC flow impairment changed from predominantly focal to predominantly extensive.

CONCLUSION

Choriocapillaris flow impairment was observed in many highly myopic eyes, even in those with mild fundus changes, and worsened with increasing severity of myopic maculopathy. Longitudinal studies are needed to assess whether CC flow impairment predicts the risk of myopic maculopathy progression.

Corneal biomechanical properties in myopic eyes evaluated via Scheimpflug imaging

BACKGROUND

To investigate the biomechanical properties of the cornea in myopic eyes using corneal visualization Scheimpflug technology (Corvis ST). The relationships between the biomechanical properties of the cornea and the degree of myopia were also investigated.

METHODS

265 eyes of 265 subjects were included. Based on spherical equivalent (SE) in diopters (D), participants were divided into four groups: low myopia/control (SE: - 0.50 to - 3.00D), moderate myopia (SE: - 3.00 to - 6.00D), high myopia (SE: - 6.00 to - 10.00D) and severe myopia (SE greater than - 10.00D). Axial length (AL), anterior segment parameters, and corneal biomechanical properties were obtained with the Lenstar LS900, Pentacam HR and Corvis ST, respectively.

RESULTS

Mean (±SD) SE was - 7.29 ± 4.31D (range: - 0.63 to - 25.75D). Mean AL was 26.31 ± 1.82 mm (range: 21.87 to 31.94 mm). Significant differences were detected within the four groups in terms of six corneal biomechanical parameters: deformation amplitude (DA), time from start until second applanation (A2-time), length of flattened cornea at the second applanation (A2-length), corneal velocity during the first and second applanation (A2-velocity), time from start to highest concavity (HC-time), and central curvature at highest concavity (HC radius). AL was positively associated with DA whereas negatively associated with A1-velocity and A2-length. SE was positively associated with A2-time, HC-time and A2-velocity, whereas negatively associated with DA. IOP was positively associated with four corneal biomechanical parameters and negatively associated with three parameters.

CONCLUSIONS

Eyes with severe myopia showed greater DA, lesser A2 time, HC time, and faster A2-velocity compared to low to high myopia. This suggests the cornea becomes weaker and more deformable with elongation of axial length with corresponding increases in myopia. DA, A2-time and A2-velocity could be useful corneal biomechanical indicators in patients with myopia.

Comparison of Corneal Biomechanical Properties among Axial Myopic, Nonaxial Myopic, and Nonmyopic Eyes

Purpose

To compare corneal deformation characteristics using ultra-high-speed Scheimpflug camera (Corvis ST) in patients with nonmyopic (NM), mild-to-moderate nonaxial myopic (MM), and high axial myopic (HM) eyes.

Methods

In this cross-sectional study, normal subjects aged >40 years with no history of ocular laser/surgery were classified according to axial length (AL) and spherical equivalence (SE) into three groups: (1) NM (SE > −0.50 D and AL < 26 mm), (2) MM (SE −6.00 D to −0.50 D and AL < 26 mm), and (3) HM (SE ≤ −6.00 D and AL ≥ 26 mm). Seven parameters including corneal deformation amplitude (CDA), inward/outward corneal applanation length, inward/outward corneal velocity (ICV and OCV), peak distance, and radius were measured. Pearson correlation and linear mixed-effects model were done.

Results

A total of 180 eyes were recruited. 98 eyes were NM, 30 eyes were MM, and 52 eyes were HM. There were significant correlations of OCV to the degree of refractive error (r = 0.203, p < 0.001) and AL (r = −0.242, p < 0.001). After adjusting for age, sex, intraocular pressure, and corneal thickness, there was significantly higher CDA (β = 0.07, p < 0.001), faster OCV (β = −0.08, p < 0.001), and smaller radius (β = −0.39, p=0.01) in the HM group compared to the NM group.

Conclusion

The higher CDA, faster OCV, and smaller radius found in the HM may suggest that these eyes have reduced ocular stiffness and may be less stable and more prone to stress.

Variation of Peripapillary Scleral Shape With Age

Purpose

To define the shape of the anterior surface of the peripapillary sclera (PPS) and evaluate its relationship with age and ocular determinants in a population-based Chinese cohort.

Methods

The optic nerve heads of 619 healthy Chinese subjects were imaged with spectral-domain optical coherence tomography. To assess the shape of the PPS/Bruch's membrane (BM), we measured the angle between a line parallel to the nasal anterior PPS/BM boundary and one parallel to the temporal side. A negative value indicated that the PPS/BM followed an inverted v-shaped configuration (peak pointing toward the vitreous), whereas a positive value indicated that it followed a v-shaped configuration (peak pointing toward the orbital tissues). A linear regression model was used to evaluate the relationship between the PPS angle and other ocular parameters.

Results

The mean PPS angle was 3.68° ± 6.73° and the BM angle was 9.69° ± 5.05°. The PPS angle increased on average by 0.233 deg/y. A v-shaped PPS was significantly associated with age (β = 0.087, P = 0.004), peripapillary choroidal thickness (β = -0.479, P < 0.001), lamina cribrosa depth (β = 0.307, P < 0.001), and BM angle (β = 0.487, P < 0.001) after adjusting for best corrected visual acuity, central corneal thickness, and axial length.

Conclusions

The anterior surface of PPS of an elderly adult population had a v-shaped configuration and was more pronounced with increasing age, thin peripapillary choroid, and a deep cup. Such a change in shape with age could have an impact on the biomechanical environment of the optic nerve head.

Distribution of scleral thickness and associated factors in 810 Chinese children and adolescents: a swept-source optical coherence tomography study

Purpose

To explore the subfoveal thickness of sclera (SST), choroid (SCT) and retina (SRT) as well as their relationship in healthy Chinese children with varying levels of refractive error.

Methods

A total of 810 healthy Chinese schoolchildren and adolescents underwent a series of comprehensive ocular examinations, as well as swept‐source optical coherence tomography (OCT) after induced cycloplegia. The thicknesses of the sclera, choroid and retina below the central fovea were measured manually, and each measurement was compared across different refractive statuses. Independent factors associated with the thickness of each layer were analysed.

Results

The mean SST, SCT and SRT were 524 ± 57 μm, 195 ± 49 μm and 224 ± 19 μm, respectively. The SSTs and SCTs of myopes were significantly thinner than those of emmetropes and hyperopes (all p < 0.001). Although the choroid seemed to be thicker in hyperopes (225 ± 46 μm) than in emmetropes (211 ± 45 μm), no statistically significant difference was observed between emmetropes and hyperopes in the sclera and choroid. Thinner SSTs and SCTs were associated with greater levels of myopia, whereas the SRT was similar in children with different myopic levels. SST (p < 0.001) and SCT (p = 0.003) as well as age (p < 0.001), sex (p < 0.001) and axial length (p < 0.001) were independently associated with spherical equivalent refraction (SER). Older age (p = 0.013), myopic‐shifted SER (p < 0.001), thicker SCT (p < 0.001) and thinner SRT (p = 0.012) were independently associated with a thinner SST.

Conclusion

The subfoveal sclera and choroid were thinner in myopes than in emmetropes and hyperopes, while the retina remains constant. Age, refractive error and choroidal and retinal thicknesses are related to subfoveal scleral thickness.

Myopic maculopathy: Current status and proposal for a new classification and grading system (ATN)

Myopia is a highly frequent ocular disorder worldwide and pathologic myopia is the 4th most common cause of irreversible blindness in developed countries. Pathologic myopia is especially common in East Asian countries. Ocular alterations associated with pathologic myopia, especially those involving the macular area-defined as myopic maculopathy-are the leading causes of vision loss in patients with pathologic myopia. High myopia is defined as the presence of a highly negative refractive error (>-6 to -8 diopters) in the context of eye elongation (26-26.5 mm). Although the terms high myopia and pathologic myopia are often used interchangeably, they do not refer to the same eye disease. The two key factors driving the development of pathologic myopia are: 1) elongation of the axial length and 2) posterior staphyloma. The presence of posterior staphyloma, which is the most common finding in patients with pathologic myopia, is the key differentiating factor between high and pathologic myopia. The occurrence of staphyloma will, in most cases, eventually lead to other conditions such as atrophic, traction, or neovascular maculopathy. Posterior staphyloma is for instance, responsible for the differences between a myopic macular hole (MH)-with and without retinal detachment-and idiopathic MH. Posterior staphyloma typically induces retinal layer splitting, leading to foveoschisis in myopic MH, an important differentiating factor between myopic and emmetropic MH. Myopic maculopathy is a highly complex disease and current classification systems do not fully account for the numerous changes that occur in the macula of these patients. Therefore, a more comprehensive classification system is needed, for several important reasons. First, to more precisely define the disease stage to improve follow-up by enabling clinicians to more accurately monitor changes over time, which is essential given the progressive nature of this condition. Second, unification of the currently-available classification systems would establish standardized classification criteria that could be used to compare the findings from international multicentric studies. Finally, a more comprehensive classification system could help to improve our understanding of the genetic origins of this disease, which is clearly relevant given the interchangeable-but erroneous-use of the terms high and pathologic myopia in genetic research.

Sequential traumatic corneal open globe rupture in a patient with osteogenesis imperfecta type I

Purpose

To report a case of sequential open globe rupture in a young patient with osteogenesis imperfecta type I following minor accidental blunt injury. This represented the patient's sole clinical manifestation of connective tissue disease, leading to a diagnosis of osteogenesis imperfecta type I at the age of 12 years old.

Observations

A 12-year-old male presented with right eye pain following accidental blunt trauma at school while wearing protective lenses. One year ago, he required surgical repair of a left open globe following blunt trauma during a middle school basketball game. His exam was significant for a full-thickness corneal laceration, necessitating open globe repair of his right eye, which was remarkably difficult given the poor tissue constitution of the cornea and sclera. He was referred to a genetics specialist, where he was found to have a pathogenic heterozygous splice site variant in the COL1A1 gene, consistent with osteogenesis imperfecta type I.

Conclusions and importance

Connective tissue disease should be considered in any case of open globe rupture following minor trauma, even in the absence of other clinical manifestations of the disease. The surgical management of these patients is particularly challenging due to the fragility of the connective tissue. Early diagnosis of connective tissue disease is important to preserve visual acuity and prevent further damage to the eyes.

Ocular biometric characteristics of cataract patients in western China

BACKGROUND

We aimed to measure ocular biometric characteristics in older cataract patients from western China.

METHODS

Ocular biometry records were retrospectively analyzed for 6933 patients with cataracts (6933 eyes) at least 50 years old who were treated at West China Hospital of Sichuan University.

RESULTS

Partial coherence laser interferometry gave the following population averages: axial length (AL), 24.32 ± 2.42 mm; anterior chamber depth (ACD), 3.08 ± 0.47 mm; keratometric power (K), 44.23 ± 1.66 diopters; and corneal astigmatism (CA), 1.00 ± 0.92 diopters. The percentage of individuals with AL > 26.5 mm was 13.66%, while the percentage with CA > 1.0 diopters was 35.54%. Mean AL and ACD showed a trend of decrease with increasing age (P < 0.001). AL correlated positively with ACD (Spearman coefficient, 0.542) and CA (0.111), but negatively with K (- 0.411) (all P < 0.01). K also correlated negatively with ACD (- 0.078, P < 0.01).

CONCLUSIONS

These results show, for the first time, that older cataract patients from western China have similar ocular biometric characteristics as other populations. The high prevalence of severe axial myopia warrants further investigation.

Three-Dimensional Eye Shape, Myopic Maculopathy, and Visual Acuity: The Zhongshan Ophthalmic Center-Brien Holden Vision Institute High Myopia Cohort Study

PURPOSE

To investigate the relationship among eye shape, myopic maculopathy, and visual acuity in highly myopic eyes using 3-dimensional (3D) magnetic resonance imaging (MRI).

DESIGN

Observational case series.

PARTICIPANTS

The study included 190 eyes of 95 participants with bilateral high myopia from the Zhongshan Ophthalmic Center-Brien Holden Vision Institute High Myopia Cohort Study, with spherical power ≤-6.00 diopters (D) in both eyes.

METHODS

The participants underwent best-corrected visual acuity (BCVA), fundus photography, cycloplegic refraction, and ocular biometry. Posterior staphyloma was identified with 3D MRI, and ocular shapes were categorized into spheroidal, ellipsoidal, conical, nasally distorted, temporally distorted, and barrel shapes according to the inferior view from T2-weighted 3D MRI (Achieva 3.0T; Philips Medical Systems, Best, the Netherlands). Myopic maculopathy was graded as C0 to C4 according to the International Photographic Classification and Grading System using fundus photography. The statistical significance of the differences in distribution of myopic maculopathy and BCVA in eyes with different ocular shapes was determined using Pearson's chi-square tests.

MAIN OUTCOME MEASURES

Distributions of myopic maculopathy and BCVA in relation to different eye shapes.

RESULTS

The mean spherical equivalent and axial length were -11.74±4.10 D and 28.18±1.73 mm in the right eyes, respectively. The same ocular shapes were observed in both eyes in 69 participants (72.6%). The predominant shape was spheroidal (53.7%), followed by nasally distorted and conical types (both 14.7%). C2 and above myopic maculopathy was observed in all barrel-shaped eyes, in 75% temporally distorted eyes, and in 71.4% nasally distorted and conical eyes. In eyes with posterior staphyloma (n = 22), 18 (81.8%) had C2 and above myopic maculopathy compared with 40 eyes (54.8%) without posterior staphyloma (n = 73). Eyes with temporal and nasal distortion, and eyes with staphyloma were more likely to have BCVA <20/40.

CONCLUSIONS

Not all highly myopic eyes are deformed. Spheroid was the predominant ocular shape in this series of young patients with high myopia bilaterally. Barrel-shaped and temporally distorted eyes present significant myopic maculopathy, whereas eyes with posterior staphyloma display more severe chorioretinal atrophy. Eyes of more deformed shapes tend to have more severe myopic maculopathy and worse BCVA.

Detection of retrobulbar blood vessels in optical coherence tomography angiographic images in eyes with pathologic myopia

Purpose

To report the detection of retrobulbar blood vessel in the optical coherence tomography angiographic (OCTA) images of two eyes with pathologic myopia.

Observations

Two eyes of 2 cases with pathologic myopia were examined by OCTA (RTVue XR Avanti, Optovue, and Cirrus 5000, Zeiss). Case 1 was a 64-year-old man, and Case 2 was a 65-year-old woman. In Case 1, the thickness of the subfoveal choroid was 38 μm and the sclera was 274 μm, and they were 17 μm and 214 μm, respectively, in Case 2. The axial length was 35.8 mm in Case 1 and 29.5 mm in Case 2. The choroidal vessels were clearly visible in the choriocapillary slab in both the RTVue and the Cirrus images. The vessels were visible in the area of the retinal pigment epithelial and choriocapillaris atrophy due to the pathologic myopia. The retrobulbar blood vessels temporal to fovea were seen in the OCTA images at the level of the outer aspect of the sclera in both cases. Cross sectional images of the retrobulbar blood vessel in both cases were observed under the sclera in serial scan images overlaid with blood flow.

Conclusions

and Importance: These in situ images of the retrobulbar blood vessels that were obtained by OCTA was possible because of the thinness of the choroid and sclera and atrophy of the choriocapillaris in these eyes with pathologic myopia. We conclude that OCTA might have utility to study the retrobulbar vascular alterations in eyes with pathologic myopia.

Current and predicted demographics of high myopia and an update of its associated pathological changes

PURPOSE

Excessive axial elongation of the eye in high myopia can cause biomechanical stretching leading to various ocular complications. The purpose of this review is to provide an update on various pathologic changes, especially in the chorio-retina and sclera that have been reported recently using advanced ophthalmic bio-imaging modalities such as optical coherence tomography, magnetic resonance imaging and fundus photography.

RECENT FINDINGS

The prevalence rates of pathologic myopia (myopic retinopathy and maculopathy) mirror the prevalence rates of high myopia as the risks of pathologic myopia increase with high myopia. Peripapillary and sub-foveal choroidal thinning, scleral thinning, and deformed/irregular eye shapes were found to be strongly associated with various pathologic myopic lesions, especially with posterior staphyloma and chorio-retinal atrophy. Considering the increasing prevalence rate of myopia and pathologic myopia, these degenerative changes are likely to increase dramatically over the next few decades due to the rapid growth in the number of individuals with high myopia and the ageing population.

SUMMARY

The current prevalence rates of pathologic myopia in older adults might have significantly underestimated the future prevalence rates and warrants age of onset of myopia being considered a major risk factor for pathologic myopia. Using advanced technology, identification of novel quantifiable chorio-retinal and scleral parameters in pathologic myopia would help to identify people at risk of developing pathologic myopia and potentially may revolutionise the management of myopia especially in risk prognostication and monitoring of disease progression.

An examination of the relation between intraocular pressure, fundal stretching and myopic pathology

Pathological myopia is one of the leading causes of visual impairment worldwide. Myopic development and progression is biomechanical and dominated by axial elongation. This clinical perspective examines some of the stretch-related fundal changes, which are associated with axial elongation and myopic pathology. The biomechanics of stretching of the fundus appears to depend on genetically and/or visual experience-based scleral changes, which reduce its thickness and elastic modulus so that it becomes more susceptible to the distending forces of intraocular pressure. These changes include reduced collagen synthesis, altered collagen fibres, tissue loss, altered proteoglycans and increased matrix metalloproteinase activity. Such changes are associated with reduced scleral rigidity and related increased potential to stretch in response to intraocular pressure. As axial elongation progresses, the sclera appears likely to continue to reduce in thickness and in its capacity to resist intraocular pressure, especially when pressure becomes elevated. Tessellation, lacquer cracks, myopic crescents, staphylomata, chorioretinal atrophy and retinal detachment are examined within a model for stretching of the fundus. Age, refractive error and axial length, for example, are associated with increased pathological progression. Myopic pathological progression can become dominated by vascular changes and include a greater risk of loss of acuity and blindness. Measures to control myopic pathology, which successfully slow or prevent stretching of the fundus, appear to be key factors in reducing or even avoiding permanent visual loss associated with this condition. For example, limiting axial elongation and related myopic fundus pathology by inhibiting changes which reduce the elastic modulus of scleral tissue is a desirable outcome from interventions to control myopia. Similarly, reducing exposure to the distending stress of elevated intraocular pressure appears to be a desirable form of intervention to control myopia, especially if myopic pathology can be reduced or prevented.

The height of the posterior staphyloma and corneal hysteresis is associated with the scleral thickness at the staphyloma region in highly myopic normal-tension glaucoma eyes

AIMS

To evaluate the characteristics of the posterior segments of eyes with high myopia and normal-tension glaucoma (NTG) and identify which ocular factors are most associated with scleral thickness and posterior staphyloma height.

METHODS

The study included 45 patients with highly myopic NTG and 38 controls with highly myopic eyes (≤-6D or axial length ≥26.0 mm). The subfoveal retinal, choroidal, scleral thickness and the posterior staphyloma heights were examined from enhanced depth imaging spectral-domain optical coherence tomography and compared between two groups.

RESULTS

Highly myopic NTG eyes had thinner subfoveal scleral thickness (473.03±43.75 vs 579.46±75.87 µm, p<0.001) and higher posterior staphyloma (97.80±70.10 vs 62.83±32.01 µm, p=0.027) than highly myopic, non-glaucomatous eyes. Subfoveal scleral thickness was significantly correlated with age, axial length, corneal hysteresis and the posterior staphyloma height of the superior quadrant, the nasal quadrant and the arithmetic mean of four quadrants in highly myopic NTG eyes. Corneal hysteresis (β=2.694, p=0.015), corneal resistance factor (β=-2.916, p=0.010) and the posterior staphyloma height of the nasal quadrant (β=-0.463, p=0.017) were significantly associated with the subfoveal scleral thickness in highly myopic NTG eyes.

CONCLUSION

Subfoveal scleral thinning and non-uniform posterior staphyloma were closely related in highly myopic NTG eyes. Corneal hysteresis, corneal resistance factor and the nasal posterior staphyloma height were associated with the scleral thickness.

Type 1 neovascularization with polypoidal lesions complicating dome shaped macula

Dome-shaped macula is described as an inward bulge of the macula within a posterior staphyloma in highly myopic eyes. Choroidal neovascularization is a known complication that can cause visual loss in dome-shaped macula. Herein, we describe a patient who presented with features of polypoidal choroidal neovascularization that developed on a background of high myopia with dome-shaped macula.

Effect of pathological myopia on biomechanical properties: a study by ocular response analyzer

AIM

To evaluate the ocular response analyzer (ORA) measurements of patients with pathological myopia in comparison with those of emmetropic control subjects, and to investigate the correlation between these ORA measurements and spherical equivalent (SE).

METHODS

Measurements of 53 eyes of 53 subjects with pathological myopia (SE>-6.00 D) were compared with those of 60 eyes of 60 emmetropic controls. Corneal hysteresis (CH), corneal resistance factor (CRF), noncontact tonometer intraocular pressure (IOPg), and corneal-compensated IOP (IOPcc) were obtained for each subject. The refractive error value was determined as SE via a cycloplegic refraction test.

RESULTS

The mean age was 54.1±18.9y (ranging from 5 to 88) in the pathological myopic group and 56.2±19.0y (ranging from 6 to 89) in the control group. There were no significant differences between the groups concerning age and sex. CH and CRF were significantly lower in the pathological myopic group than in the control group (P<0.001, P=0.005, respectively). IOPcc and IOPg were significantly higher in the pathological myopic group than in the control group (P<0.001, P=0.009, respectively). There were significantly positive correlations between CH and SE (r=0.565, P<0.001) and between CRF and SE (r=0.364, P=0.007). There were significantly negative correlations between IOPcc and SE (r=-0.432, P=0.001) and between IOPg and SE (r=-0.401, P=0.003).

CONCLUSION

The present study displayed that pathological myopia affected biomechanical properties measured by ORA. The results of corneal biomechanical properties measured by ORA may need to be appreciated by taking refraction into account. Further, pathological myopia might be related with the increased IOP.

Dome-shaped macular configuration: longitudinal changes in the sclera and choroid by swept-source optical coherence tomography over two years

PURPOSE

To study longitudinal changes in the posterior pole in eyes with dome-shaped macular configuration within the staphyloma.

DESIGN

Prospective, longitudinal study.

METHODS

We prospectively examined the macular area in 35 eyes (26 patients) with dome-shaped macular configuration and high myopia (mean spherical equivalent, -14.83 ± 4.50 diopters) using swept-source optical coherence tomography. Scleral and choroidal thicknesses were measured at the fovea and at 4 parafoveal locations 2000 μm from the foveal center. Height of the macular bulge was measured as well.

RESULTS

During the mean follow-up of 24.8 ± 2.5 months, the scleral thickness significantly decreased at the fovea from 496.1 ± 95.7 μm to 484.7 ± 96.2 μm (P < .001) and at all 4 parafoveal locations (P < .001, respectively). The scleral thinning was asymmetric, with an estimated decrease per year of 5.6 μm at the foveal center, 11.1 μm superiorly, 12.1 μm inferiorly, 10.4 μm temporally, and 5.8 μm nasally. The ocular concavities deepened over time, and mean macular bulge height increased from 136.5 ± 60.9 μm to 157.6 ± 67.0 μm (P < .001). The choroid within the staphyloma showed generalized thinning during follow-up. Mean choroidal thickness decreased significantly at the fovea from 28.3 ± 17.2 μm at baseline to 22.9 ± 17.2 μm (P < .001).

CONCLUSIONS

Progressive asymmetric scleral thinning occurred in the macular region of eyes with dome-shaped macular configuration. The scleral thinning was more pronounced in the parafoveal area than at the foveal center, resulting in an increase of the macular bulge height.