This is a prospective Multi-Center Observational Study to assess the reliability and validity of the Multi-Luminance Y-Mobility Test (MLYMT) and Multi-Luminance Shape Discrimination Study (MLSDT) Main Outcome Measures: (i) Performance scores in normal and severely visually impaired subjects with a clinical diagnosis of retinitis pigmentosa (RP) on MLYMT and MLSDT at multiple luminance levels and (ii) reliability and content validity of MLYMT and MLSDT.

Two assessment visits will be conducted in order to evaluate functional visual performance in severely vision impaired subjects with RP and normally sighted subjects. Two visits will occur at week 0 and week 4 with functional vision assessments occurring at both visits in order to assess visit-to-visit variability. For the MLYMT, navigational vision will be assessed using each eye and binocularly at up to 6 different light levels (range 0.3 to 100 lux). Subjects will also perform the Multi-Luminance Shape Discrimination Test (MLSDT) which assesses near object recognition under different lighting levels. MLYMT and MLSDT performance will be evaluated together with Best Corrected Visual Acuity (BCVA), Visual Field (VF) and responses to visual function questionnaires. Subjects will be assigned to one of two cohorts based on presence or absence of RP in addition to BCVA performance.

Inclusion Criteria:

1. Age ≥ 18 years
2. Able to comprehend and give informed consent.
3. Able to comply with testing and all protocol tests.
4. Eligible for 1 of 2 cohorts listed below:

Cohort 1: Normally Sighted Participants with clinically normal ocular findings and BCVA better than logMAR 0.3 (as confirmed by ETDRS letter score > 73) in each eye Cohort 2: Severely Sight Impaired Participants with BCVA no better than logMAR 1.6 in better seeing eye, and worse than LogMAR 1.9 in the worse seeing eye, and a clinical diagnosis of advanced RP

Exclusion Criteria:

1. Concurrent participation in any interventional clinical trial or receipt of an investigational drug within the previous 6 months
2. Presence of any condition other than RP Disease that impairs visual acuity or visual fields e.g., visually significant cataract or visual field loss in glaucoma
3. Presence of neurological condition that impairs visual acuity or visual field, e.g., hemianopia secondary to stroke
4. Individuals who refuse or are incapable of performing mobility testing
5. Individuals with retinal prosthesis (such as ARGUS-II)
6. Participation in Nanoscope studies NTXMCO-002 (RESTORE) or NTXMCO-004 (STARLIGHT)

This study will enroll approximately 35 adult subjects, to one of 2 cohorts. Subjects who meet all the inclusion criteria and for whom none of the exclusion criteria apply will be eligible for enrollment.

The results of the clinical trial will be made available when the study is completed. The results will be published on this site and be available to conference presentations and publications.

12 months after the study is completed

Reliability and Validity of MLYMT and MLSDT