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OPTX 20/20 and Press-On Optics bifocal segments: an evaluation
S M Bell1, K J Gurholt, R L Yolton
1Pacific University, College of Optometry, Forest Grove, Oregon, USA.
Journal of the American Optometric Association
|October 6, 1997
Summary
Removable bifocal segments from OPTX 20/20 offer better optical quality and near vision for higher powers, while Press-On Optics segments are comparable for lower powers. Both provide satisfactory adhesion for temporary use.
Area of Science:
- Ophthalmology
- Optometry
- Vision Science
Background:
- Evaluation of OPTX 20/20 and Press-On Optics removable bifocal segments.
- Assessment focused on optical quality, visual effects, and environmental stability.
Purpose of the Study:
- To compare the optical performance and visual impact of two types of removable bifocal segments.
- To determine the stability of these segments under simulated environmental conditions.
Main Methods:
- Optical quality assessed by measuring sphere, cylinder, and spherical equivalent powers in central and peripheral segments (+1.00 to +2.50 D).
- Visual acuity and contrast sensitivity were evaluated.
- Adhesion to CR-39 carriers tested under simulated environmental conditions.
Main Results:
- OPTX 20/20 segments showed better optical quality and a 1 Snellen line advantage in near acuity at +2.00 D.
- Some OPTX 20/20 and Press-On Optics segments failed ANSI standards due to unwanted cylinder power.
- Contrast sensitivity was not significantly different between the two types for low and mid-spatial frequencies.
Conclusions:
- OPTX 20/20 segments offer superior optical characteristics and visual acuity for higher powers.
- Lower power OPTX 20/20 segments exhibited reduced optical quality due to distortion and cylinder.
- Both segment types demonstrated adequate adhesion, suitable for temporary, removable bifocal additions.