examines the influence of lens-induced defocus on contrast sensitivity-a crucial aspect of visual performance.Each participant experiences both positive and negative defocus through different lenses, with measurements taken for contrast sensitivity using the Pelli-Robson chart. Outcomes are evaluated at baseline, 2 weeks, and 4 weeks to understand the effect of defocus over time.

Additional data on symptoms like visual fatigue and computer vision syndrome are gathered using the Visual Fatigue Questionnaire (VFQ) and the Computer Vision Syndrome Questionnaire (CVS-Q), respectively. This study's findings could be instrumental in refining optical treatments, offering insights into how defocus impacts visual function across refractive conditions. Results may ultimately benefit optometric practices by guiding lens prescriptions for improved contrast sensitivity and quality of life for myopic and non-myopic individuals alike.

Inclusion Criteria:

• Adults aged 18 to 50 years.
• Participants with a confirmed diagnosis of myopia or non-myopia.
• Best corrected visual acuity of 20/30 or better.
• No history of ocular surgery or significant ocular disease.
• Informed consent was obtained.

Exclusion Criteria:

• Individuals with a history of systemic diseases affecting vision (e.g., diabetes, hypertension).
• Presence of binocular vision anomalies or strabismus.
• Pregnant or nursing women.
• Any current use of medications affecting visual function (e.g., medications causing visual side effects).