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Purpose: Non-linear regression analysis was used to determine dark adaptation indices in people with retinitis pigmentosa and in control subjects., Methods: Dark adaptation data were collected for 13 people with retinitis pigmentosa and 21 controls using the Goldmann-Weekers Dark Adaptometer. Data were analysed using an exponential non-linear regression model and dark adaptation indices derived. The results were compared to age-related values., Results: The mean cone threshold of the group with RP (4.73 +/- 0.19 log units) was significantly greater than that found in the control group (3.69 +/- 0.12 log units). The rate of cone dark adaptation in the RP group was not significantly different from that of the control group. The a break in the RP group (6.46 +/- 0.70 minutes) was delayed when compared to the control group (4.29 +/- 0.21 minutes) and the rate of rod dark adaptation in the RP group was slower (10 +/- 2 per cent per minute) than that of the control group (15 +/- 1 per cent per minute)., Conclusions: This study has shown that a relatively simple data analysis can provide a more quantitative and intuitive description of dark adaptation rates in people with retinal disease. This technique will enable more effective use of dark adaptometry as a supplement to objective electrophysiology, when monitoring people with retinitis pigmentosa.

Abstract: Purpose: This study examined which color vision test was superior in the detection of acquired color vision deficiencies and the relative magnitudes of red–green (RG) and blue–yellow (BY) discrimination losses in retinitis pigmentosa (RP). Methods: Color vision examinations were conducted using Standard Pseudoisochromatic Plates Part 2 (SPP Part 2) and a flicker threshold test (TMT) in 21 RP and 21 age- and sex-matched normals. The TMT test consists of luminance, BY and RG flicker tests. Relative Operating Characteristic analysis (ROC) was used to determine the effectiveness of each test. Bigger ROC area gain and high performance (%) indicate a better test. Regression and correlation analyses were used to determine the relative magnitudes of RG and BY discrimination losses for the SPP Part 2. For TMT the findings were represented graphically where the mean log sensitivity was plotted against the frequency of mean luminance; RG and BY flicker individually and the range was plotted with the 5th and 95th percentile. Results: Both tests were able to determine BY and RG acquired color vision deficiencies in RP patients. SPP Part 2 showed the highest area gain (0.39) and performance (78%). The TMT generally showed less area gain and performance compared to SPP Part 2. Pearson''s correlation coefficient analysis on the RG and BY SPP Part 2 test plates showed a strong relationship (r =0.96, p <0.0001) between RG and BY discrimination losses suggesting that RP patients suffer roughly equal losses in RG and BY discrimination. Analysis of the TMT also showed an equal loss of sensitivity across all the frequencies in all three tests suggesting an overall reduction of sensitivity confirming the non-specific frequency and non-color specific loss. Conclusions: The SPP Part 2 appears to be a superior test compared to TMT in detecting acquired color vision deficiencies in RP patients. RP subjects also suffer both RG and BY acquired color vision deficiencies. [Copyright &y& Elsevier]