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Elham Hatef Naimi, Mostafa Hanout, Owhofasa Agbedia, Ahmadreza Moradi, Diana Do, David Guyton, Quan Dong Nguyen; Longitudinal Comparison of Visual Acuity as Measured by ETDRS Chart and by Potential Acuity Meter in Eyes with Macular Edema and Its Relationship with Macular Sensitivity and Thickness. Invest. Ophthalmol. Vis. Sci. 2013;54(15):4921. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To conduct a longitudinal comparison of visual acuity measured by the ETDRS chart and by the Potential Acuity Meter (PAM) in eyes with macular edema under medical treatment for edema and its relationship with macular sensitivity and thickness
Patients with macular edema (ME) are enrolled in an ongoing prospective study. Patients have follow up visits every 2-4 weeks. At the initial and each follow up visit, best refractive correction for all patients is determined using the ETDRS protocol, and best-corrected visual acuity (BCVA) is assessed using the ETDRS chart as well as by the PAM. Macular sensitivity and thickness are measured by an automatic fundus perimetry/tomography system [OPKO/OTI]. The relationships between BCVA measurements with each of the two systems and macular sensitivity/ thickness are evaluated using mixed-effect modeling.
Thirty-eight eye-visits of 14 patients are included in the study. Five patients (10 eyes) had one follow up visit after the initial one. Ages range from 49 to 84 years (median: 66 yrs). BCVA using the ETDRS chart ranges from 20/20 to 20/200 (median: 20/50). BCVA measured by the PAM ranges from 20/20 to 20/400 (median: 20/40). Macular thickness ranges from 112 to 743 microns (median: 346). Macular sensitivity ranges from 0 to 20 dB (median: 10). Differences between BCVA measured with the two systems are evaluated using LogMAR values. The mean LogMAR value using the ETDRS chart is 0.45 (95% confidence interval (CI): 0.35, 0.56) while it is 0.44 (95% CI: 0.31, 0.57) using the PAM (P-value > 0.05). The LogMAR values using the ETDRS chart as well as the PAM are correlated (r= 88%). The difference between LogMAR value for BCVA measured with PAM and the ETDRS chart changes by an average of 0.004 (95% confidence interval (CI): 0.002, 0.011) per 1 unit increase in macular thickness while adjusted for macular sensitivity and other confounders.
There is a high correlation between VA measurements with the PAM and the ETDRS chart. VA values measured with the PAM are very close to those measured with the ETDRS chart, although a better VA median may be obtained for PAM values. The difference between LogMAR values for BCVA measured with PAM and the ETDRS chart changes slightly with every micron increase in macular thickness.
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