Abstract
Purpose: :
To analyze by OCT the Optic Nerve Head (ONH) in patients with Leber’s Hereditary Optic Neuropathy (LHON) with and without recovery of visual acuity.
Methods: :
52 patients (mean age: 34.03±12.3 years) with LHON, as defined by the presence of a pathogenic mtDNA point mutation, were compared to an age matched control group of 45 individuals. Patients were further stratified according to the presence (29 patients) and absence (23 patients) of recovery of visual acuity and according to the mtDNA mutation (11778, 3460 and 14484). Stratus OCT was used to analyze the ONH (Fast optic disc acquisition protocol). One randomly selected eye was considered for each patient and control individual. Groups were compared by one–way ANOVA analysis of variance followed by Bonferroni post–hoc test.
Results: :
All LHON patients revealed a reduced rim area, integrated rim volume and rim width (p <0.0001) and increased cup area, CD vertical ratio and CD area (p<0.0001) compared to controls. The rim area was significantly reduced in LHON patients with no recovery as compared to patients with visual recovery (p=0.022). Moreover, the vertical disc diameter in LHON patients with no recovery was reduced compared to controls (p=0.048), while LHON patients with visual recovery were similar to controls. Accordingly, after stratifying the data by mutation, the 14484 patients, who presented the highest rate of visual recovery (5 out of 6), showed also the largest disk area (p=0.034).
Conclusions: :
The differential OCT analysis of ONH morphology in LHON patients with and without recovery of visual acuity is strongly suggestive that a smaller optic disk represents a negative prognostic factor influencing the final visual outcome. This observation is indirectly confirmed by the further finding that the 14484 patients, well known for a better visual prognosis, presented with larger disk area. This OCT study provides for the first time credit to the previously proposed hypothesis that the anatomical size of the optic disk may influence the clinical expression of LHON.
Keywords: neuro-ophthalmology: optic nerve • optic disc