Functional Visual Outcome of 1^st vs 2^nd Affected Eye in Treated LHON Patients at 1 Year

Abstract

Purpose: Leber’s Hereditary Optic Neuropathy (LHON) is a mitochondrial optic neuropathy with no definitive therapy. Involvement of the first eye is usually followed by the second eye within a few months. Thus, the second eye is exposed to systemic treatment, such as quinone therapy, earlier relative to its onset. We carried out a retrospective chart review to test our hypothesis that functional visual outcome is better in the 2^nd affected eye at 1 year in treated LHON patients.

Methods: Charts from 2009 to 2014 were analyzed at a university affiliated eye institute. Patients were diagnosed with LHON, and were seen at 1 year ± 2 months after conversion for the 2nd eye. 20 patients were identified and all were given quinone therapy for the duration of the year. 14 began treatment after both eyes were affected (hence earlier for 2^nd eye) and 6 began after one eye was affected (hence before visual loss in the 2^nd eye). Average time to treatment after involvement of the 1^st eye was 172 days. LogMAR visual acuity (VA), retinal nerve fiber layer (RNFL) thickness, and mean deviation (MD) were recorded for 1^st and 2^nd eyes affected. A two-tailed Student’s t-test was used for statistical analysis.

Results: At 1 year in the 1^st affected eye, patients treated after both eyes were affected had an average VA of 1.73 ± 1.67, an average MD of -21.44 ± 7.39, and an average RNFL thickness of 64.75 ± 13.25. In the 2^nd affected eye, they had an average VA of 1.78 ± 1.77, an average MD of -15.82 ± 11.93, and an average RNFL thickness of 66.13 ± 10.97. At 1 year in patients treated after both eyes were affected, P values for the 1^st vs 2^nd affected eye were 0.4546 for VA, 0.1768 for MD, and 0.5342 for RNFL thickness. At 1 year in the 1st affected eye, patients treated between affected eyes had an average VA of 2.00 ± 2.08, an average MD of -29.08 ± 3.17, and an average RNFL thickness of 65.60 ± 11.01. In the 2^nd affected eye, they had an average VA of 1.93 ± 2.10, an average MD of -24.22 ± 4.99, and an average RNFL thickness of 60.20 ± 9.73. At 1 year in patients treated between affected eyes, P values for the 1^st vs 2^nd affected eye were 0.1620 for VA, 0.1556 for MD, and 0.1540 for RNFL thickness.

Conclusions: In this LHON cohort, there was a trend but no statistically significant difference in visual outcome between the 1^st and 2^nd affected eye at 1 year. Hence, the timing of quinone therapy does not appear to be critical.