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Elham Hatef Naimi, Afsheen Khwaja, Millena Bittencourt, Mohamed Ibrahim, Yasir Sepah, Jangwon Heo, Diana Do, David Guyton, Quan Dong Nguyen; Is Visual Acuity an Accurate Predictor of Macular Sensitivity? Visual Acuities as Measured by the ETDRS Chart and by the Potential Acuity Meter as Predictors of Macular Sensitivity Measured by an Automatic Fundus Perimetry/Tomography System. Invest. Ophthalmol. Vis. Sci. 2012;53(14):2674.
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To compare visual acuities as measured by the ETDRS chart and by the Potential Acuity Meter (PAM) as predictors of macular sensitivity measured by an automatic fundus perimetry/tomography system.
Patients with macular edema (ME) secondary to diabetic retinopathy, uveitis, age-related macular degeneration, and vein occlusion were enrolled. Best refractive correction for all patients was determined using the ETDRS protocol, and best-corrected visual acuity (BCVA) was assessed using the ETDRS chart as well as by the PAM. Macular sensitivity was measured by an automatic fundus perimetry/tomography system [Scanning laser ophthalmoscope/ Spectral domain optical coherence tomography (SLO/OCTTM), OPKO/OTI]. The relationship between the BCVA measurements with each of the two systems, and macular sensitivity was evaluated using mixed-effect modeling with random intercepts while adjusting for age, gender, underlying disease, macular thickness, fixation stability, and fixation location.
Fifty-two eyes of 30 patients were included in the study. Ages ranged from 23 to 87 years (median: 62 yrs). Nineteen patients (63%) had diabetic ME, 8 (27%) uveitic ME, 1 (3%) AMD, and 2 (7%) had vein occlusion. BCVA using the ETDRS chart ranged from 20/25 to 20/400 (median: 20/80). BCVA measured by the PAM ranged from 20/20 to 20/400 (median: 20/40). Macular sensitivity ranged from 0 to 18 decibels (dB) (median: 8). Differences between BCVA measured with the two systems were evaluated using LogMAR values. The mean LogMAR value using the ETDRS chart was 0.41 (95% confidence interval (CI): 0.34, 0.49) while it was 0.34 (95% CI: 0.26, 0.42) using the PAM (P-value: 0.003). The LogMAR values using the ETDRS chart as well as the PAM were highly correlated (r= 0.78). Macular sensitivity decreased by an average of 6.00 dB (95% confidence interval (CI): -14.18, 2.25) per 1 unit increase in LogMAR value for BCVA measured with the ETDRS chart. The macular sensitivity decreased by an average of 8.66 dB (95% CI: -16.31, -1.01) per 1 unit increase in LogMAR value for BCVA measured with the PAM.
There is a high correlation between VA measurements with the PAM and the ETDRS chart. VA values measured with the PAM were statistically significantly better than those measured with the ETDRS chart. Macular sensitivity varied with different values of VA measured with the two systems. VA measured with the PAM is a more sensitive predictor of macular sensitivity.
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