C. Bellusci

Association of Optic Disc Size with Development and Prognosis of Leber’s Hereditary Optic Neuropathy

PURPOSE To study the optic nerve head (ONH) morphology of patients with Lebers hereditary optic neuropathy (LHON) in a large family from Brazil carrying the 11778/ND4 mutation and in a case series of unrelated Italian families bearing different mitochondrial DNA (mtDNA) pathogenic mutations. METHODS Enrolled in the study were 15 LHON-affected patients (LHON-affected) and 45 LHON unaffected mutation carriers (LHON carriers) belonging to the previously reported Brazilian SOA-BR LHON pedigree and 56 LHON-affected and 101 LHON carriers from 45 unrelated LHON Italian pedigrees molecularly defined. The LHON-affected were subgrouped according to the extent of visual recovery. All individuals underwent optic nerve head (ONH) analysis by optical coherence tomography. RESULTS In the Brazilian sample, the mean optic disc area was significantly larger in LHON carriers than in the control group (P=0.002). In the Italian sample, the mean optic disc area and vertical disc diameter were significantly higher in LHON carriers than in both LHON-affected (respectively, P=0.008 and P<0.001) and control subjects (P<0.001 in both cases). The LHON-affected with visual recovery had a significantly larger vertical disc diameter when compared with those without visual recovery (P=0.03). CONCLUSIONS The results, revealing that the ONH size is larger in LHON carriers than in LHON-affected, suggest a protective role for this anatomic trait. Such a hypothesis is reinforced by the observation that, among the LHON-affected, larger discs correlated with visual recovery and better visual outcome. The findings may be relevant for prognosis and provide a mechanism for identifying nuclear-modifying genes implicated in the variability of penetrance in LHON.

Retinal nerve fiber layer thickness in nonarteritic anterior ischemic optic neuropathy: OCT characterization of the acute and resolving phases.

BackgroundTo evaluate longitudinal changes in retinal nerve fiber layer (RNFL) thickness in patients with nonarteritic anterior ischemic optic neuropathy (NAION) using optical coherence tomography (OCT).MethodsProspective, observational case series study. Sixteen eyes from 15 consecutive patients affected with NAION were analyzed. The fellow unaffected eyes served as controls.Patients were divided into three different study groups: (1) patients with visual field (VF) defect confined to the inferior hemifield (five eyes), (2) patients with diffuse VF loss (seven eyes), and (3) patients with central or centrocecal scotoma (four eyes). The main outcome was peripapillary RNFL thickness measurement by Stratus-OCT.ResultsIn group 1, OCT demonstrated RNFL involvement limited to the temporal , superior and nasal optic disc quadrants, both in acute and athophic stages. Diffuse RNFL damage involving all quadrants around the disc was observed in group 2 patients. Group 3, by contrast, revealed RNFL atrophy limited to the superior and temporal sectors of the disc.ConclusionsOCT can identify different patterns of RNFL involvement specific to different classic VF defects in eyes with NAION. Our results corroborate previous histologic findings in optic nerves affected with NAION.