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A. Berezovsky, J.M. Pereira, P.Y. Sacai, S.C. Fantini, S.R. Salomao; Visual Acuity and Rod Function in Patients With Retinitis Pigmentosa . Invest. Ophthalmol. Vis. Sci. 2003;44(13):3104.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To investigate visual acuity and rod function, and to correlate them to different clinical parameters in patients with retinitis pigmentosa (RP). Methods: A consecutive group of 182 patients with RP (104 males and 78 females), aging from 6-79 years (mean= 36.3±18.1) had their monocular best corrected visual acuity (BCVA) measured by the ETDRS chart and rod function assessed by full-field ERG and dark-adapted thresholds. The distribution of different genetic subtypes of RP was 22.0% autosomal dominant, 14.8% X- linked, 23.1% autossomal recessive and 40.1% isolated. History of consanguinity was found in 35 (19.2%) patients. Forty-one patients (22.5%) were 20 years old or less, 69 (38%) ranged from 21-40 years, 54 (29.7%) from 41-60 years, and 18 (9%) were 61 years or older. Peak-to-peak amplitude and b-wave implicit time were measured and statistically analyzed (one-way ANOVA). Pearson correlation was performed between rod amplitude and dark-adapted threshold and rod amplitude and visual acuity. Results: Visual acuity was 20/40 or better in 56 patients (30%), 20/50-20/150 in 45 patients, 20/200-20/400 in 39 patients (21.4%) and were worse than 20/400 in 42 patients (23%). In the group with better acuity scores, 27% were autossomal dominant, 22.2% X-linked, 36.5% recessive and 32.4% isolated. No statistical differences were found in visual acuity among the four RP subtypes. Nyctalopia has begun earlier in X-linked patients, when compared with the remaining groups (p=0.011). A negative correlation was found between dark-adapted threshold and scotopic rod amplitude (Pearson correlation coefficient= -0.493 and P= 0.000). There were no significant relationships between visual acuity and both ERG and dark-adapted thresholds. No statistical differences were detected in ERG parameters, dark-adapted thresholds and visual acuity between consanguineous and non-consanguineous patients. Conclusions: In a cohort of RP patients, 30.7% had vision of 20/40 or better. Rod function loss was highly correlated when assessed either electrophysiologically (ERG) and psychophysically (dark-adapted threshold). No correlation was found between rod response measured by ERG, dark-adapted threshold measured psychophysically and visual acuity.
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