Optical Coherence Tomography Measurement and Visual Outcome in Acute Central Retinal Artery Occlusion

Normalized Reflectivity of Middle Limiting Membrane on SD-OCT: A Measure of Acute Ischemia in CRVO

PURPOSE

To validate the quantification of the prominent middle limiting membrane (PMLM) sign, a marker of mild-to-moderate acute ischemic damage on optical coherence tomography (OCT), by measuring middle limiting membrane (MLM) reflectivity in patients with central retinal vein occlusion (CRVO) and to investigate the prognostic impact of this measure.

METHODS

Spectral Domain (SD)-OCT B-scans of 30 patients with CRVO, either sole CRVO or combined central retinal artery and vein occlusion (CCRAVO), were analyzed retrospectively and graded as PMLM present or absent. Normalized MLM reflectivity was calculated as a ratio of the maximum reflectivity within a MLM target layer and the average reflectivity of the retinal pigment epithelium (RPE).

RESULTS

Discrimination between OCT B-scans graded as PMLM present or absent based on ROC analysis was far superior with normalized MLM reflectivity (AUC >0.90) than using MLM reflectivity without normalization (AUC = 0.70). Normalized MLM reflectivity was significantly higher in study eyes than healthy fellow eyes as well as in patients with CCRAVO versus sole CRVO. Although normalized MLM reflectivity correlated significantly with baseline and outcome BCVA, we found no significant difference comparing patients with ischemic CRVO versus non-ischemic CRVO.

CONCLUSIONS

Quantifying MLM reflectivity requires normalization due to shadowing, which is usually caused by retinal haemorrhages in CRVO. RPE reflectivity proved to be a suitable reference layer. Greater normalized MLM reflectivity as a measure of mild-to-moderate acute ischemic damage indicated a worse prognosis regarding visual function in CRVO, however, it allows no risk assessment regarding the development of capillary non-perfusion or anterior segment neovascularization.

Correlation of visual acuity changes and optical coherence tomography imaging in patients with central retinal artery occlusion post-arterial thrombolysis

This retrospective study investigates the correlation between visual acuity changes and structural modifications observed through optical coherence tomography (OCT) in patients with central retinal artery occlusion (CRAO) treated with urokinase. Conducted at the Neuro-Ophthalmology Center of Xi'an People's Hospital from January 2022 to May 2023, the study included 217 CRAO patients (217 eyes), comprising 157 males and 60 females, aged 18 to 83 years (mean age: 57.8 ± 13.3 years). Key data were collected on visual acuity, ocular motility, and various imaging techniques at admission and post-thrombolysis. Results showed a significant improvement in visual acuity from 2.4 ± 0.5 to 1.9 ± 0.7 (P < 0.001) after treatment. Notably, patients with severe retinal damage had poorer visual recovery compared to those with milder damage. OCT analysis revealed a decrease in macular foveal retinal thickness from 415.5 ± 107.7 μm to 362.1 ± 93.8 μm (P < 0.001). Correlation analysis confirmed an association between visual acuity and retinal thickness (P < 0.001). Inter-observer variability for OCT grading was assessed using Cohen's Kappa, which yielded a Kappa value of 0.873 (P < 0.001). This study underscores the relationship between visual recovery and retinal structural changes in CRAO patients, emphasizing the efficacy of urokinase treatment, particularly in mild to moderate cases, and the need for personalized therapeutic strategies based on condition severity.

Evaluation of optic coherence tomography findings in patients with inflammatory bowel disease

BACKGROUND

Ocular complications are known to appear in inflammatory bowel disease (IBD). Among these, posterior segment complications can lead to substantial morbidity. The aim of the study is to evaluate the retinal nerve fiber layer (RNFL), ganglion cell-inner plexiform layer (GCIPL), and macula thickness measurement in patients with IBD.

METHODS

A total of 118 patients with IBD (42 Crohn's disease (CD), 76 ulcerative colitis (UC)) and 52 healthy subjects were included in the study. RNFL, GCIPL, and macula thickness were measured using spectral-domain optical coherence tomography (SD-OCT).

RESULTS

The central macular thickness was increased, mean and all superior quadrants of GCIPL thickness measurements were significantly decreased, but RNFL thickness wasn't changed in CD compared to healthy subjects. Although the central macular thickness increased, no change was observed in mean RNFL and GCIPL in UC compared to healthy subjects. Mean RNFL, GCIPL, and macular thickness did not differ during the remission and active phases of the disease in IBD. There was no difference in RNFL, GCIPL, and macular thicknesses in CD patients in terms of the location and behavior of the disease. A significant thickness increase was found in extensive type UC for inferior RNFL value compared to the left side and proctitis.

CONCLUSIONS

IBD may cause an increase in macular thickness. This finding may be related to the inflammation or ischemia of the retina. The use of SD-OCT in ophthalmologic examination in patients with IBD may enable early detection of retinal changes and alert the clinician to complications of IBD.

Inner Retinal Thinning Comparison between Branch Retinal Artery Occlusion and Primary Open-Angle Glaucoma

Purpose: to assess the tomographic retinal layers' thickness in eyes affected by branch retinal artery occlusion (BRAO) and to compare it to those of patients affected by primary open angle glaucoma (POAG). Methods: retrospective review of 27 patients; 16 with BRAO (16 eyes) and 11 with POAG (20 eyes) were identified among those who received SD-OCT scans, including analysis of macular retinal nerve fiber layer (mRNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), neuroretinal rim (NRR), circumpapillary RNFL at 3.5 mm and hemisphere asymmetry (HA). Results: the total IPL and INL thinning difference between the two groups was statistically significant (p = 0.0067 and p < 0.0001, respectively). The HA difference for the total macular thinning, mRNFL, GCL, IPL and INL (p < 0.0001) was also statistically significant. The analysis of the average total retinal thinning, total mRNFL and GCL thinning showed no statistically significant difference between the two groups. Conclusions: unilateral inner retinal thinning may represent a sign of temporal BRAO, particularly for INL thinning and HA difference over 17µm in total retinal layer thinning. This information is particularly useful in the diagnosis of previous, undiagnosed BRAO and may help prevent further retinal arterial occlusion and possible cerebrovascular incidents.

Central Retinal Artery Occlusion in COVID-Associated Mucormycosis

Introduction

Significant surge of mucormycosis was reported in the Indian Subcontinent during the second wave of the COVID-19 pandemic. COVID-associated mucormycosis (CAM) was defined as the development of features of mucormycosis with prior or current history of COVID-19 infection. Rapid angioinvasion is an important characteristic of mucormycosis. Authors intended to find out the prevalence of retinal arterial occlusion and its association with vascular embolic occlusion elsewhere in the body among CAM patients in this study.

Methods

This was an observational study. All consecutive-confirmed cases of mucormycosis (n = 89) and age-/gender-/risk factor-matched controls (n = 324) admitted in the designated COVID center were included in the study. All cases and controls underwent comprehensive ophthalmological, otorhinological, and neurological examinations. All necessary investigations to support the clinical diagnosis were done. Qualitative data were analyzed using the Chi-square test. Quantitative data for comparison of means between the cases and controls were done using unpaired t-test.

Results

Twenty-one (23.59%) patients manifested the defined outcome of central retinal artery occlusion (CRAO). Among age-matched control, with similar diabetic status, none had developed the final outcome as defined (P < 0.05). About 90.47% of subjects with CRAO presented with no perception of light vision. Thirteen subjects (61.9%) with the final outcome developed clinical manifestations of stroke during the course of their illness with radiological evidence of watershed infarction (P = 0.001). Orbital debridement was performed in 9 (42.85%) subjects while orbital exenteration was done in 8 (38.09%) subjects.

Conclusions

CRAO in CAM patients was found to have aggressive nature turning the eye blind in a very short period of time. CRAO can serve as a harbinger for subsequent development of more debilitating and life-threatening conditions such as stroke among CAM patients.

Measurement of Foveal Retinal Thickness in Myopic Patients Using Different Display Modes on Optical Coherence Tomography: A Retrospective, Cross-Sectional Study

INTRODUCTION

The aim of this work is to investigate the differences in the measurement of foveal retinal thickness in myopic patients between two display modes (1:1 pixel and 1:1 micron) on optical coherence tomography (OCT).

METHODS

Horizontal OCT line scan through the central fovea was used for manual measurement of foveal retinal thickness under the two display modes, and the values were compared using Wilcoxon signed-rank test. Correlations between the OCT image tilting angle (OCT ITA) and differences in OCT measurement were analyzed by Spearman's test.

RESULTS

127 participants with a median age of 28 years, a median spherical equivalent (SE) of - 8.5 D, and a median axial length (AL) of 27.04 mm. There were significant differences between the two display modes, with a median absolute difference (median relative difference) of 13.33 μm (2.75%) for the central foveal thickness (CFT), 5.33 μm (1.28%) for the Henle fiber and outer nuclear layer thickness (HFL + ONL), 3 μm (6.47%) for the external limiting membrane to ellipsoid zone distance (ELM-EZ), and 4 μm (8.77%) for the ellipsoid zone to retinal pigment epithelium distance (EZ-RPE) (all p < 0.05). The differences in foveal retinal thickness between the two display modes were significantly correlated with the OCT ITA (r = 0.732 for CFT, 0.561 for HFL + ONL, 0.642 for ELM-EZ, and 0.471 for EZ-RPE, all p < 0.05).

CONCLUSIONS

Disparities between the two display modes were found in the manual measurement of foveal retinal thickness and correlated to the OCT ITA.

Analysis of risk and protective factors associated with retinal nerve fiber layer defect in a Chinese adult population

AIM

To investigate the risk and protective factors associated with the retinal nerve fiber layer defect (RNFLD) in a Chinese adult population.

METHODS

This study was a cross-sectional population-based investigation including employees and retirees of a coal mining company in Kailuan City, Hebei Province. All the study participants underwent a comprehensive systemic and ophthalmic examination. RNFLD was diagnosed on fundus photographs. Binary logistic regression was used to investigate the risk and protective factors associated with the RNFLD.

RESULTS

The community-based study included 14 440 participants. There were 10 473 participants in our study, including 7120 males (68.0%) and 3353 females (32.0%). The age range was 45-108y, averaging 59.56±8.66y. Totally 568 participants had RNFLD and the prevalence rate was 5.42%. A higher prevalence of RNFLD was associated with older age [P<0.001, odds ratio (OR): 1.032; 95% confidence interval (CI): 1.018-1.046], longer axial length (P=0.010, OR: 1.190; 95%CI: 1.042-1.359), hypertension (P=0.007, OR: 0.639; 95%CI: 0.460-0.887), and diabetes mellitus (P=0.019, OR: 0.684; 95%CI: 0.499-0.939). The protective factors of RNFLD were visual acuity (P=0.038, OR: 0.617; 95%CI: 0.391-0.975), and central anterior chamber depth (P=0.046, OR: 0.595; 95%CI: 0.358-0.990).

CONCLUSION

In our cross-sectional community-based study, with an age range of 45-108y, RNFLD is associated with older age, longer axial length, hypertension, and diabetes mellitus. The protective factors of RNFLD are visual acuity and central anterior chamber depth. These can help to predict and evaluate RNFLD related diseases and identify high-risk populations early.

Analysis of Microvasculature in Nonhuman Primate Macula With Acute Elevated Intraocular Pressure Using Optical Coherence Tomography Angiography

Purpose

To investigate responses of macular capillary vessel area density (VAD) of superficial and deep retinal vascular plexuses to elevations in intraocular pressure (IOP) in cynomolgus macaque monkeys using optical coherence tomography angiography (OCTA).

Methods

In five general anesthetized male cynomolgus monkeys, the IOP was increased incrementally by 10 mmHg from baseline (10 mmHg) to 70 mmHg and then decreased back to 10 mmHg (recovery state). Structural OCT (30° × 30°) and OCTA (20° × 15°) centered on the macula were obtained at each IOP and 3, 15, and 30 minutes after recovery. En face images of the superficial vascular complex (SVC) and deep vascular complex (DVC) were extracted, and VAD (%) compared with that at baseline was calculated.

Results

The VADs in the SVC and DVC at baseline and at 30 mmHg IOP were 34.96%, 34.15%, 35.38%, and 30.12%, respectively. The VAD plateaued until 30 mmHg; however, the VAD was affected more in the DVC than in the SVC (P = 0.008) at 30 mmHg. It showed a significant reduction at 40 mmHg (16.52% SVC, P = 0.006; 18.59% DVC, P = 0.012). In the recovery state, the SVC showed full retention of baseline VAD, but the DVC maintained VAD approximately 70% of that at baseline. Structural OCT showed hyperreflectivity in the nuclear layer, retinal swelling, and an undifferentiated ellipsoid zone from 50 mmHg.

Conclusions

Despite physiological autoregulation, perifoveal microcirculation was affected at high IOP ≥ 40 mmHg, especially in the DVC, which explains the pathological mechanism of macular vulnerability in ischemic diseases.