A multifocal electroretinography study to evaluate risk of developing macular hole in the fellow eye of patients suffering with unilateral macular hole

Background

Visual outcome of eyes has often been found to be unsatisfactory even after successful closure of a macular hole, owing to factors like persistent metamorphopsia, scotoma, and reduced sensitivity. Therefore, it becomes critical to evaluate and study the probability and risk of developing a macular hole in the fellow eyes of the patient. This study analyzed the multifocal electroretinographic responses to help predict the risk of macular hole development in fellow eyes.

Methods

In total 26 fellow eyes, 26 eyes with macular hole, and 50 eyes of 25 controls were enrolled prospectively. The retinal responses from the different rings were compared in the three groups. Optical coherence tomography was done to rule out macular pathology or vitreomacular traction in the fellow eyes.

Results

All the fellow eyes under observation showed significantly reduced mean amplitudes of retinal response densities, in all rings as compared with controls (31.45 ± 10.38 versus 48.87 ± 7.55, p = 0.00). Three of the fellow eyes developed a macular hole during the 24 months observation period. The prevalence of fellow eye involvement was 11.5%. Relative risk of developing macular hole in the fellow eye ranged from 25 to 75.

Conclusion

All the fellow eyes, including those that did not develop a macular hole, showed significantly reduced responses on multifocal electroretinogram. This indicates that macular hole may not be a focal disease. It may have widespread functional deficit which is bilateral in nature and suggestive of a degenerative or ischemic insult.

Optical coherence tomography angiography findings in fellow eyes of choroidal neovascularisation associated with central serous chorioretinopathy

AIM

To evaluate the optical coherence tomography angiography (OCTA) features of fellow eyes of patients with unilateral choroidal neovascularisation (CNV) associated with chronic central serous chorioretinopathy (CSCR).

METHODS

Medical records of patients with chronic CSCR who had undergone OCT angiography of both the eyes were reviewed. Patients with evidence of unilateral CNV detected by conventional imaging (OCT, fluorescein angiography and/or indocyanine green angiography) were included in the study. The OCT and OCTA characteristics of fellow eyes were analysed.

RESULTS

Forty patients (80 eyes-40 fellow eyes) with chronic CSCR with evidence of CNV in one eye were included. Mean age of the patients was 54.9±9.9 years and 82.5 % were males. Twenty-five (62.5%) fellow eyes had flat irregular pigment epithelial detachment on OCT, out of which 21 had internal hyper-reflectivity. A definite vascular network was picked up by OCTA in 9 of these 40 fellow eyes (22.5%) which was not detected on conventional imaging. In addition, two eyes had an ill-defined hyper-reflectivity, which could not be classified as a definite network at that point of time. The networks detected on OCTA in fellow eyes were mostly inactive, suggesting a subclinical neovascularisation.

CONCLUSION

One-fourth of fellow eyes showed vascular network which could not be diagnosed on conventional imaging which highlights the importance of imaging both the eyes of chronic CSCR for early detection of CNV using OCTA. Further longitudinal studies are needed to assess the clinical course of such subclinical vascular networks in CSCR.

Mechanism of delayed conduction of fellow eyes in patients with optic neuritis

To test the hypothesis that latency delay in the fellow eyes of optic neuritis (ON) patients and to compensate for delayed transmission of visual information, latency change of multi-focal visual evoked potential (mfVEP) traces in fellow eyes of 15 ON patients were analyzed. Patients with low risk (LR) for developing multiple sclerosis (MS) were examined separately from MS patients to isolate effect of cortical plasticity from potential pathological changes in disseminated disease. The small increase in latency in fellow eyes of LR group was statistically not significant. In MS patients, the latency was significantly delayed (P<0.02). The magnitude of the latency change in the fellow eyes did not correlate with the severity of latency delay in the affected eyes (R²<0.02, P=0.3). The differences between ON patients with and without MS, reported here, suggest that the presence of disseminated disease plays critical role in latency delay of the fellow eye.