Spectral Sensitivity Analysis for Testing of Rod or Cone Function in Patients with RPE65 Genotype
Wegscheider E.1, Wabbels B.1, Schillinger R.1, Preising M.1, Hamel C.2, Lorenz B.1
1Dept. of Paediatric Ophthalmology, Stabismology and Ophthalmogenetics, University Hospital, Regensburg; 2Inserm U 254, Montpellier/F
Purpose: RPE65 is an essential protein in the recycling of retinol. Absence of RPE65 is associated with virtual absence of active rhodopsin in the rods of RPE65-/- mice. Despite this, ERG studies with high intensity flashes indicated rod mediated answers. As Patients with the RPE65 genotype have some color vision, cone mediated vision appears possible.
Method: A total of 7 patients aged 10-43 years suffering from an early onset retinal degeneration associated with mutations in the RPE65 gene underwent spectral sensitivity testing under dark adapted conditions and three patients also under light adapted conditions using a HFA modified for automated scotopic and spectrally resolved perimetry (16 monochromatic filters 400 - 700 nm, mean bandwidth 9.6 nm).
Results: In the group 15 years and younger (4 patients) V.A. ranged from 0.1- 0.3. No photophobia was present, and bright light was necessary for optimal visual performance. The two older patients (19 and 27 years) had only residual visual function and were photophobic. In contrast, the oldest patient had a VA of 0.1 and was able to distinguish colors like the patients under 15 years. Spectral sensitivity testing
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