The Photopic Negative Response: An Objective Measure of Retinal Ganglion Cell Function in Patients With Leber's Hereditary Optic Neuropathy.

Purpose: The photopic negative response (PhNR) is a slow negative component of a flash photopic full-field ERG that has been shown to be specific for retinal ganglion cell (RGC) activity. Direct evaluation of RGC function is desirable in patients with Leber's hereditary optic neuropathy (LHON) in which the loss of central acuity can make it difficult to monitor patients with standard metrics. The purpose of this study was to evaluate the use of PhNR as an objective noninvasive clinical metric in LHON. Methods: Full-field photopic ERG recordings were collected in subjects with the mt.11778G>A/ND4 LHON mutation using a red on blue stimulus. The PhNR was identified using a computer-based automated detection system, and data were manually examined to remove movement artifacts. Results: The PhNR amplitude was compared between controls (n = 13), carriers (n = 17), and affected (n = 6). Mean PhNR amplitude decreased significantly across groups (P < 0.0001). Post hoc Tukey's test revealed a significant decrease in PhNR amplitude between carriers and controls (P < 0.05) and between carriers and affected (P < 0.01). Conclusions: We are able to demonstrate that the PhNR amplitude is significantly decreased in patients affected by LHON compared to carriers in a well-described pedigree. Surprisingly, there was also a decrease in PhNR in carriers, suggesting potential subclinical RGC dysfunction in some carriers. This is important in patients affected with LHON who typically have a dense central scotoma. The PhNR may be a useful objective outcome measure for future clinical trials.

Bilateral optic neuritis in wegener granulomatosis.

A 32-year-old patient with recurrent sinusitis had severe visual loss from optic neuropathy. Imaging revealed severe bone destruction and soft tissue densities of the paranasal sinuses and enhancement of the dura of the frontal sinuses, optic canals, and superior orbital fissures bilaterally. Endoscopic sinusectomy with biopsy showed granulomatous vasculitis compatible with Wegener granulomatosis (WG). The patient was treated with intravenous and oral corticosteroids and oral cyclophosphamide that led to rapid and dramatic visual recovery. This case draws attention to the fact that optic neuritis may be an early inflammatory manifestation of WG and that rapid diagnosis and aggressive anti-inflammatory treatment is critical before inflammation of arteries leads to infarction and irreversible visual loss.