Abstract
Purpose: :
To analyze visual function and foveal characteristics in a group of patients affected by oculocutaneous albinism (OCA).
Methods: :
10 patients (5 females and 5 males) affected by oculocutaneous albinism (OCA) and 1 patient (a female) affected by Hermansky Pudlak Syndrome (HPS) were considered. Mean age was 23.5 years (range 4-43 years). All patients underwent: molecular characterizations, clinical examinations (ocular motility, visual acuity, biomicroscopic examination of iris transillumination and macular translucency), instrumental evaluations included macular cross sectional and macular thickness studies by spectral domain OCT (Heildelberg, Germany) and visual evoked potential (VEP).
Results: :
All patients presented: horizontal nystagmus, iris transillumination and translucent macular pigment epithelium. OCT images (macular cross section and thickness) and mean best corrected visual acuity were respectively: in four patients nearly planar thickness across macula, mean foveal thickness of 332,8 ± 30,1 µm and 0.8 ± 0.1 logMAR; in two patients doming of macular region, mean foveal thickness of 291,5 ± 55,6 µm and 0.7 ± 0.2 logMAR; in five patients shallow foveal depression, excavation of inner retinal neurons in region of increased retinal profile, mean foveal thickness of 319,5 ± 13,91 µm and 0.5 ± 0.3 LogMAR. In all patients OCT showed changes in photoreceptor layer, persisting nerve fiber layer and presence of multiple inner retinal layers at the center of the fovea. VEP documented excessive decussation of the retinostriate fibers at the optic chiasm in all subjects.
Conclusions: :
In albino patients both clinical and instrumental examinations could be useful to better analyze visual function and foveal morphology. Clinical evaluation may disclose nystagmus, iris transillumination and macular translucency that are correlated with low visual acuity. In our study OCT examination shows better the relation between the spectrum of foveal development (from absence to shallow), the abnormal displacement of retinal layers and visual function.
Keywords: retinal development • visual development • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)