Inclusion Criteria:  Clinically diagnosed with rod-cone degeneration and at least two; pathogenic or likely pathogenic mutations in one of the Usher type 2 genes; Willing and able to complete the informed consent process; Ability to return for all study visits over 48 months; Age ≥ 16 years.  Both eyes must meet all of the following:  Clinical diagnosis of a rod-cone degeneration; Clear ocular media and adequate pupil dilation to permit good quality photographic imaging; Ability to perform kinetic and static perimetry reliably; Baseline visual acuity ETDRS letter score of 54 or more [approximate Snellen equivalent 20/80 or better]; Stable fixation; Clinically determined [on Octopus 900 Pro] kinetic visual field III4e area 7,5°, or more in the study eye.  Exclusion Criteria:  Mutations in genes that cause autosomal dominant RP, X-linked RP, or presence of biallelic mutations in autosomal recessive RP/retinal dystrophy genes other than Usher genes; Expected to enter experimental treatment trial at any time during this study History of more than 1 year of cumulative treatment, at any time, with an agent associated with pigmentary retinopathy (including hydroxychloroquine, chloroquine, thioridazine, and deferoxamine).  If either eye has any of the following, the patient is not eligible:  Current vitreous hemorrhage; Current or any history of rhegmatogenous retinal detachment; Current or any history of (e.g., prior to cataract or refractive surgery) spherical equivalent of the refractive error worse than -8 Diopters of myopia; History of intraocular surgery (e.g., cataract surgery, vitrectomy, penetrating keratoplasty, or LASIK) within the last 3 months; Current or any history of confirmed diagnosis of glaucoma (e.g., based on glaucoma visual field, nerve changes, or glaucoma filtering surgery); Current or any history of retinal vascular occlusion or proliferative diabetic retinopathy; Expected to have cataract removal surgery during the study; History or current evidence of ocular disease that, in the opinion of the investigator, may confound assessment of visual function; History of treatment for retinitis pigmentosa that could affect the progression of retinal degeneration (including participation in a clinical trial within the last year or a retained drug delivery device).  If either ear has any of the following, the patient is not eligible:  The audiometric PTA(1-2-4kHz) for the best hearing ear should not exceed 75dB HL; Patients with bilateral cochlear implants cannot participate in the study; A planned, second, cochlear implantation during the study.