Abstract
Purpose :
In the treatment of retinal diseases, it is important to evaluate whether if the vision loss was due to retinal disease versus refractive errors or media opacities. The Potential Acuity Meter (PAM) assesses visual potential by projecting a Snellen eye chart onto the retina using a light beam with a 0.1 mm pinhole aperture. We wish to compare the utility of the PAM to the Retinal Acuity Meter (RAM) in assessing potential visual acuity (VA) in patients with retinal disorders. The RAM uses a modified pinhole spectacle and an illuminated near card held fixed at 40 cm.
Methods :
Patients with retinal disorders seen between August and November 2016 in the retina service at the University of California, San Diego were eligible. All participants were measured with the RAM and PAM to assess the potential VA. Patients with significant non-retinal disorders were excluded. The best-corrected VA by refraction was compared to RAM and PAM measurements.
Results :
54 eyes from 48 patients were enrolled. 8 eyes had a history of retinal detachment status-post pars plana vitrectomy (PPV). 12 eyes had epiretinal membranes (ERM),10 were status-post ERM peel. 8 eyes had dry age-related macular degeneration (AMD). 4 had wet AMD treated with anti-VEGF. 5 had proliferative diabetic retinopathy, 1 eye had undergone PPV. 7 had diabetic macular edema treated with anti-VEGF. 7 eyes had a history of macular hole status-post PPV. 3 eyes had vitreomacular traction. 3 eyes had retinal vein occlusion treated with anti-VEGF and steroids.1 eye had post-cataract cystoid macular edema. 3 eyes had posterior vitreous detachment. 2 had diabetes with mild retinopathy.
Average overall ETDRS VA was 20/96 (corrected VA= 20/80, uncorrected VA= 20/128). Average PAM was 20/50 and RAM was 20/40 (p< 0.001). Both PAM and RAM readings were correlated to corrected VA, r2= 0.37 and r2= 0.47, respectively.
Conclusions :
This study demonstrated that while RAM and PAM both correlated with corrected EDTRS VA, the correlation was mildly higher for RAM. Also, the RAM had a tendency to give a better potential VA than the PAM. These findings may suggest that perhaps the RAM may better assess the potential VA than does PAM, given the higher illumination of the near card compensating for the decreased contrast sensitivity seen in patients with retinal disorders.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.