Abstract
Purpose: :
Visual acuity is used as the gold standard for visual function evaluation, but it reflects just one of the characteristics of visual function, that frequently does not correlate with patients perception or disability. Knowledge of fixation characteristics, stability and retinal sensitivity may be important for understanding patient’s quality of vision and perhaps planning treatment. We analyzed the characteristics of retinal fixation and sensitivity in patients with different eye diseases using MP-1 microperimetry and correlated them with best corrected visual acuity measurements (BCVA).
Methods: :
We evaluated fixation stability (% of fixation points within 2° and 4° diameter circle) and retinal sensivity (within the 2° and 4° diameter circle) in 104 eyes (62 patients) with different retinal pathologies by means of microperimetry MP-1. 22 were healthy eyes, 21 had hypertensive retinopathy, 3 glaucoma, 12 retinitis pigmentosa, 1 retinal detachment, 11age related macular degeneration (AMD) , 16 high myopia, 18 diabetes. Mean age was 55,11 ± 15,47.
Results: :
BCVA was 0.01 ±0.67 logMAR. Fixation within the 2° and 4° diameter circle was 82.27± 17.78% and 94.12 ±11.04% respectively. Mean retinal sensitivity within the central 2° and 4° diameter circle was 16.26± 4,21dB and 16.51± 4.05 dB respectively. Fixation stability correlates most with retinal sensitivity indipendently on the retinal disease (r: 0.96; r:0,97). BCVA correlates better to retinal sensivity than to fixation stability (r= 0.70 vs r=0,24 for the central 2° and r=0,72 vs r=0,29 for the 4° diameter circle respectively).
Conclusions: :
Our data demonstrate that microperimetry and in particular retinal sensitivity measurements represent a better functional testing than BCVA for quantifying visual function in a great variety of diseases, because it incorporates a functional measure that may potentially supplement the predictive value of visual acuity.
Keywords: visual acuity • retina • perimetry