Assessment of Three Basic Progressive Lens Designs

The purpose of the study is to evaluate the preference, adaptability, and visual performance of three progressive lens designs. The difference in these lens designs is a variation of zone sizes for intermediate and near vision. The clinical trial helps manufacturers and eye care practitioners to give detailed suggestions to patients. Study participants will be experienced progressive addition lens wearers, which will be recruited by advertisements, by email, and with direct person-to-person solicitation. The study will be conducted at the Eye Care Institute at the Patient Care Center Western University of Health Sciences, Pomona, CA, 91766. For each participant, the study is completed in around two months and requires three separate visits.

Inclusion criteria

• Age: 45 to 70 years old.
• Visual Acuity: far & near monocular: cc ≥ 20/20 (decimal cc ≥ 1.0)
• Normal binocular vision (at distance & near: no strabismus on cover testing, aligning prism of less than 2Δ horizontally or vertically, stereoacuity of 2' or better at distance and near).
• Prescription is in the range:

• Spherical power: less than +/-6.00 D
• Cylindrical power: less than -2.75 D
• Addition: 1.50 D - 2.50 D
• Difference in power (spherical equivalent) between eyes: less than 2.00 D

Exclusion criteria

• Have never worn any progressive lens design.
• First prescription for progressive lenses.
• Prescription found during visit#1 varies from current prescription more than 0.50 D in any meridian.
• Currently wearing single vision lenses with accommodative support.
• Double vision or prismatic prescription in current glasses.
• Known ocular disease including strabismus, any pathology, any eye surgeries that may affect visual acuity.
• Use of systemic or ocular medications that are likely to affect vision.
• Balance problem/vertigo problem.
• Concurrent participation in other vision-related research.