Visual function testing, Visual Field Analysis and Visual evoked potentials were described in detail previously [22], [25].
In considering the appropriate unit of analysis (i.e., eye or person), we found that the gains in visual function are greater when the analysis focused on those who received cataract extractions in both eyes rather than those who received the first eye only.
At this stage we also performed analysis of visual function.
Our results were consistent with what we found from analysis of visual function tests performed in the lab [ 19].
In fact, in our analysis, the visual function measures in our participants while on placebo were better than the expected natural course of RP.
For the objective analysis of the visual function in mice, we examined the second-order kernel of mfERGs, which is impaired in patients with glaucoma.
The other additional analysis performed was a comparison between changes in visual function under treatment and the natural course of retinitis pigmentosa, considering that this natural course entails a gradual deterioration of visual function.
Both ways will be employed to ensure the robustness of findings: comparison of visual function in two treatment groups on a continuous scale, and event analysis, where we define a case as progressed if a measurement in visual function test is outside of a 95% confidence interval of the original distribution for this test on two consecutive biannual examinations.
Statistical analysis was performed to determine whether any differences existed between visual function measures from each group (refractive error, visual acuity, binocular status, accommodative function and reading speed and accuracy).
Using three main perimetric testing techniques and standardized field analysis our study aimed firstly to increase our understanding of visual function and in particular visual fields in patients who have undergone a PPV for complications of PDR.
For all visual function measures there were no significant differences between the groups before intervention (one way analysis of variance [ANOVA] p > 0.05).
