Abstract
Abstract: :
Purpose: Visual function after photodynamic therapy (PDT) for age–related subfoveal choroidal neovascularisation is generally evaluated by measuring distant visual acuity. We investigated the effect of PDT on other aspects of visual function such as reading acuity, text acuity and contrast sensitivity, in order to determine its possibly additional value in clinical decision making. Methods: We compared the measurements of reading acuity (RA), text acuity (TA), and contrast sensitivity (CS) to visual acuity (ETDRS) measurements at baseline and after one year in 50 patients who received PDT for age–related subfoveal choroidal neovascularisation. RA and TA were measured with use of the Laboratory of Experimental Ophthalmology (LEO) chart. Visual acuity (VA) was measured with use of the Early Treatment Diabetic Retinopathy (ETDRS) chart. CS was measured with the Pelli–Robson chart. For comparison all ETDRS and logarithmic scale results were transformed into an equal scale from 0 (no detection of visual function) to 100 (full visual function). Results: After transformation mean VA at baseline was 58.5±13.4 SD, mean CS was 65.0±15.0 SD, mean TA was 61.5±14.6, and mean RA was 55.1±14.7. After one year PDT–treatment, mean VA–loss was 9.8±23.9, mean CS loss was 6.7±23.6, mean TA loss was 12.0±22, and mean RA loss was 10.0±21.0. Mean values of CS, TA and RA did not significantly differ. The loss of VA was significantly correlated to CS loss (r=0.54,p<0.001), TA loss (r=0.64, p<0.001) and RA loss (r=0.72, p<0.001). Conclusions: Measurements of reading acuity, text acuity and contrast sensitivity at baseline and after one year of PDT–treatment seem to correlate well to the measurements of ETDRS letter counting. For this reason, extensive measurements of visual function may not be of additional value in clinical decision making.
Keywords: age-related macular degeneration • photodynamic therapy • visual acuity