Inclusion Criteria:  RP patients with the best-corrected visual acuity (BCVA) between 20/30 and 20/120.  Exclusion Criteria:  Patients with other types of retinal dystrophy Systemic or syndromic RP RP patients with cystoid macular edema (CME) and the presence of cystoid changes in the foveal area RP patients with other concomitant ocular diseases RP patients with a history of any ocular surgery or intravitreal injection within 6 months before the study enrollment RP patients who have received any supplemental drugs during the past three months before the study enrollment