Natural History Study of Patients With EYS-Associated RP

• Characterize the natural history of retinal degeneration associated with biallelic pathogenic mutations in the EYS gene over 4 years, as measured using functional, structural, and patient-reported outcome measures
• Investigate whether structural outcome measures can be validated as surrogates for functional outcomes in individuals with biallelic pathogenic mutations in the EYS gene
• Evaluate risk factors (genotype, phenotype, environmental, and comorbidities) for progression of the outcome measures at 4 years in individuals with biallelic pathogenic mutations in the EYS gene
• Evaluate variability and symmetry of left and right eye outcomes over 4 years in individuals with biallelic pathogenic mutations in the EYS gene

Inclusion criteria

• Willing to participate in the study and able to communicate consent during the consent process
• Ability to return for all study visits over 48 months
• Age ≥ 18 years
• Must meet one of the Genetic Screening Criteria, defined below:

Screening Group A: At least 2 disease-causing variants in the EYS gene which are homozygous or heterozygous in trans, based on a report from a clinically-certified lab (or a report from a research lab that has been pre-approved by the Study Committee) Screening Group B: Only 1 disease-causing variant in the EYS gene, based on a report from a clinically-certified lab (or a report from a research lab which has been pre-approved by the Study Committee) Screening Group C: At least 2 disease-causing variants in the EYS gene which are unknown phase, based on a report from a clinically-certified lab (or a report from a research lab which has been pre-approved by the Study Committee) Note pertaining to all Screening Groups: if a participant has a variant(s) of unknown significance, he/she would still qualify as long as there is at least 1 disease-causing variant(s) on the EYS gene.

Ocular Inclusion Criteria:

Both eyes must meet all of the following:

• Clinical diagnosis of retinal dystrophy
• Clear ocular media and adequate pupil dilation to permit good quality photographic imaging

Exclusion criteria

• Mutations in genes that cause autosomal dominant retinitis pigmentosa (ADRP), X-linked retinitis pigmentosa (RP), or presence of biallelic mutations in autosomal recessive RP/retinal dystrophy genes other than EYS.
• 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)

Ocular exclusion Criteria:

If either eye has any of the following, the participant 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 glaucomatous visual functions changes or nerve changes, or history of glaucoma filtering surgery)
• Current or any history of retinal vascular occlusion or proliferative diabetic retinopathy
• History or current evidence of ocular disease that, in the opinion of the investigator, may confound assessment of visual function
• History or evidence of active treatment for retinitis pigmentosa that could affect the progression of retinal degeneration, including:
• Any use of ocular stem cell or gene therapy
• Treatment with an ophthalmic oligonucleotide within the last 9 months (last treatment date is less than 9 months prior to Screening Visit date)
• Treatment with any other product within five times the expected half-life of the product (time from last treatment date to Screening Visit date is at least 5 times the half-life of the given product)