Relation Between Macular Thickness and Central Visual Function in Patients Affected by Retinitis Pigmentosa: New Clinical Outcomes

Abstract

Purpose:: To determine the correlation between macular sensitivity (microperimetry), macular thickness (OCT Stratus), 30 Hz flicker and visual acuity in patients affected by retinitis pigmentosa with visual acuity better than 0.4.

Methods:: Thirty eyes of 15 consecutive patients were underwent to static threshold perimetry with the MP1 Micro Perimeter (Nidek Inc., Italy), optical coherence tomography (OCT3) and 30 Hz flicker in order to calculate macular sensitivity, retinal thicknesses and retinal function. Visual acuity were measured with Early Treatment Diabetic Retinopathy Study (ETDRS) charts. We have subdivided the macular region in 5 fields and we have correlated the thickness and the retinal sensitivity of each field. We have moreover correlated 30 Hz flicker and the visual acuity to the thickness and the sensibility in each field.

Results:: A significant correlation coefficient was noted between retinal sensitivity and normalized macular thickness in foveal region (r=0.502, P=0.024). Moreover the Pearson correlation analysis showed high significant correlation between visual acuity and macular sensitivity in everyone of the 5 fields (P<0.01). At last the 30 Hz flicker correlated significantly with sensitivity in the superior region (r=0.551, P=0.041), but we have not found correlation between 30 Hz flicker and thickness.

Conclusions:: The macular sensitivity seems to be appropriate helpful variable of visual function, independent of macular thickness data and 30 Hz flicker. The RP progression may be well documented by adding macular sensitivity mapping by microperimetry to macular thickness, 30 Hz flicker and visual acuity determination. The microperimetry could be considered a supplementary predictive value of the retinal function as well correlated with all the morphologic and functional parameters.

Keywords: retinal degenerations: hereditary • macula/fovea • visual acuity