Visual loss and perimetric sensitivity in eyes with retinitis pigmentosa

To investigate the various perimetric parameters that best predict reduction of best-corrected visual acuity (BCVA) to worse than 0.5 in the near future in eyes with retinitis pigmentosa (RP).

The most recent records obtained by Humphrey Field Analyzer (HFA) central 10-2 perimetry were studied for the right eyes of 123 patients (60 men and 63 women) with typical RP. The correlation between various parameters of perimetric sensitivity and BCVA was retrospectively studied. The receiver operating characteristic (ROC) curves were used to find the best parameter to discriminate eyes with BCVA ≥0.5 from those with BCVA <0.5.

Spearman rank correlation coefficients with logMAR BCVA were the highest for the foveal threshold (FT) and mean sensitivity of the test points within 1.4° of the fixation point (MS1.4). The ROC curve analysis revealed that the area under the curve was the largest for the MS1.4 among all the perimetric parameters for discriminating eyes with BCVA ≥0.5 from those with BCVA <0.5. The cutoff value of 30 dB showed 100 % specificity and 57 % sensitivity.

The risk of vision decreasing below 0.5 in the near future may be predicted when the mean sensitivity within 1.4° of the fixation point in the HFA 10-2 reaches 30 dB in eyes with RP.