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Diffractive properties of the Diffrax bifocal contact lens
1Centre for Eye Research, School of Optometry, Queensland University of Technology, Brisbane, Australia.
Summary
The Pilkington Diffrax lens functions optically as a diffractive bifocal contact lens. Its chromatic aberration and over-refraction performance align with theoretical predictions for bifocal contact lenses.
Area of Science:
- Ophthalmology
- Optics
- Vision Science
Background:
- Bifocal contact lenses aim to correct presbyopia by providing clear vision at multiple distances.
- Diffractive optics offer a potential mechanism for multifocal correction in contact lenses.
Purpose of the Study:
- To optically verify the performance of the Pilkington Diffrax diffractive bifocal contact lens.
- To assess the lens's longitudinal chromatic aberration and over-refraction characteristics.
Main Methods:
- Optical bench testing of the Pilkington Diffrax lens.
- In-situ evaluation of the lens on the eye.
- Measurement of longitudinal chromatic aberration.
- Assessment of over-refraction compared to distance subjective refraction.
Main Results:
- The Pilkington Diffrax lens exhibits optical behavior consistent with a diffractive bifocal contact lens.
- Longitudinal chromatic aberration measurements align with theoretical predictions.
- On-eye over-refraction results match the predicted distance subjective refraction.
Conclusions:
- The Pilkington Diffrax lens functions as a diffractive bifocal contact lens.
- The lens's optical performance, including chromatic aberration and refractive correction, is validated by the study.
- Findings support the theoretical model for this type of bifocal contact lens design.