Purchase this article with an account.
Elke K. Altpeter, Beate Leo-Kottler, Bjoern R. Blanke, Angelika I. Cordey, Nhung X. Nguyen, Susanne Trauzettel-Klosinski; Reading Ability And Fixation In Patients With Leber's Hereditary Optic Neuropathy. Invest. Ophthalmol. Vis. Sci. 2012;53(14):4376.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Leber's hereditary optic neuropathy (LHON) is a rare genetic disease (1:50000) with a juvenile onset. The patients develop a central scotoma due to a degeneration of retinal ganglion cells which is associated with mitochondrial mutations of the ND4, ND6 and ND1 gene.The aim of this study was to evaluate the adaptation and reading strategies in LHON patients because they have more difficulties compared with patients with other central scotomas of other origin such as age related macular degeneration or hereditary maculopathy.
From a total of 180 patients from our clinic with a positive genetic analysis of LHON, only 31 patients matched with the inclusion criteria: visual acuity more than 0.02, central scotoma, reading possible with magnifying aid.12 male patients completed the examination which included best corrected visual acuity (EDTRS), magnifying need, reading speed (with magnifying aid) using IReST cards (International Reading Speed Texts), fixation by corneal reflexes and by SLO (Rodenstock scanning laser ophthalmoscope), perimetry (Tübingen Automated Perimeter 30°), slitlamp-examination and funduscopy.
The mean age at examination was 40 (±0.15), range 20-70 years. The mean best corrected distance visual acuity with the better eye was 1.3 logMar (±0.23) (0,05 or 10/200).The mean magnifying need was 16x (± 7). Reading speed was 51 (± 17) words per minute, all but one patient used an electronic magnifying device.In the binocular assessment by corneal reflexes 6 patients showed a fixation in of 5°-15° upgaze, 3 fixated centrally, 3 patients fixated downgaze 5-15°.The mean central scotoma size was 15° (±7°).The characteristic finding at the SLO was the highly unstable eccentric fixation in 9 patients using a fixation area of 1-2 optic disc diameters. 3 patients with the lowest magnification need (6x) used 2 different defined preferred retinal loci (near-central).
The reason for the rehabilitation problem in LHON patients is the highly unstable eccentric fixation with a large fixation area. This leads to difficulties in adaptation with developing an ineffective reading behaviour.
This PDF is available to Subscribers Only