Development of a validated computer-based instrument (software program) for the assessment of intermediate visual acuity.

Development of a validated computer-based instrument (software program) for the assessment of intermediate visual acuity (IVA). It is known that no validated method for the evaluation of IVA exists.

Primary objective of the study is to validate a specific computer-based chart (optotype) that will enable: a) comparative studies among different groups of presbyopic patients with refractive errors (ie. myopia, hyperopia, and/or astigmatism), and, b) assessment of the efficacy of surgical refractive procedures (ie. LASIK) on presbyopic patients.

Intermediate Visual acuity chart is similar to the prevalent Jaeger chart. It consists of short blocks of text in various type sizes.The computer screen is set at a specific reading distance (1 meter) and the patient is asked to read the passage with the smallest type he/she can see. According to the smallest text he/she can read, IVA is classified from IVA1 (which is considered the equivalent of 20/20 distance visual acuity) to IVA5

Validation of the computer-based IVA chart will be done by correlating the results of the IVA chart to the corresponding ones from the validated 20/20 distant and Jaeger near visual acuity charts, in a random sample of study participants with different refractive errors and different near and distant visual acuities.

Inclusion Criteria:

• native Greek participants or foreigners with perfect knowledge (verbal and written) of Greek language

Exclusion Criteria:

• glaucoma or suspicion for glaucoma,
• corneal disease or suspicion for corneal disease
• fundus disease or suspicion for fundus disease
• pregnancy or nursing,
• underlying autoimmune disease
• mental or neurologic disease

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