A Prospective Observational Study to Assess the Reliability and Validity of the MLSDT

Inclusion Criteria: * Males and females, age ≥ 18 years * Able to comprehend and give informed consent. * Able to comply with testing and all protocol tests. * Eligible for 1 of 3 cohorts listed below: Cohort 1: Normal-Sighted Participants with clinically normal ocular findings and BCVA range 20/16 to \<20/40 in each eye (ETDRS letter score 71 - 90) Cohort 2: Moderately-Sight Impaired Participants with a BCVA range of 20/40 to \<20/200 (ETDRS letter score of 36 - 70) and a clinical diagnosis of STGD/GA Cohort 3: Severely-Sight Impaired Participants with a BCVA range of 20/200 to 20/800 (ETDRS letter score of 5 - 35) and a clinical diagnosis of advanced STGD/GA * Clinical diagnosis of STGD for cohorts 2 and 3 * Clinical diagnosis for GA (due to AMD) for cohorts 2 and 3 * Participants who have had anti-VEGF therapy 2 weeks prior to enrollment have to demonstrate 3 months of vision stability and be fluid free on OCT. Exclusion Criteria: * Concurrent participation in any interventional clinical trial or receipt of an investigational drug within the previous 6 months * Presence of any condition other than STGD or GA from AMD on slit lamp exam or dilated ophthalmoscopy that impairs visual acuity or visual fields e.g., corneal opacity, visually significant cataract or visual field loss in glaucoma * No intra-vitreal injection with anti-VEGF two weeks prior to the study * Presence of neurological condition that impairs visual acuity * Individuals who refuse or are incapable of performing the MLSDT of BCVA tests * Individuals with retinal prosthesis (such as ARGUS-II)