Objective: to compare the disease progression in retinitis pigmentosa-affected kids receiving vitamin A supplements to those who do not. Study design and type: Non-randomised retrospective study Methodology: The study comprised 55 children receiving vitamin A and 25 not taking vitamin A who had various hereditary forms of typical retinitis pigmentosa. The data analysis was done in December 2022 and the patient examinations took place between June 2016 to May 2022 We used age adjusted dose of vitamin A ≤15 000 IU/d. By using repeated-measures longitudinal regression, we may estimate the mean exponential rates of change of the full-field cone electroretinogram amplitude to 30-Hz flashes without and with confounding variables. Results: The mean and SD age of the 55 kids in the vitamin A cohort was 9.1± 1.9years, and 38 (69%) of them were boys. The estimated mean rates of change using the unadjusted model were 0.0713 loge units/y (6.9% per year) for the group receiving vitamin A and 0.1419 loge units/y (13.2% per year) for the control cohort (difference, 0.0706 loge units/y; 95% CI for the difference, 0.0149-0.1263 loge units/y; P =.01). The modified model supported the observation that the vitamin A group saw a slower mean rate of decrease (difference, 0.0771 loge-unit per year; 95% CI for the difference, 0.0191-0.1350 loge-unit per year; P =.009).Regarding ocular safety, there were no differences between cohorts in the mean exponential rates of change in visual acuity and visual field area, nor in the incidences of falling to a visual field diameter of 20° or less or a visual acuity of 20/200 or less in at least 1 eye.