Clinical Assessment of a Customized Free-form Progressive Addition Lens Spectacle

Clinical Assessment of a Customized Free-form Progressive Addition Lens Spectacle

The purpose of this study was to compare objective clinical measures of visual performance and subjective measures of satisfaction and preference between standard progressive addition lens (PAL) spectacles and a new type of free-form surfaced, optically customized PAL spectacle.

In a double-masked crossover trial, 95 experienced wearers wore customized free-form PAL spectacles (Test) and standard non-free-form PAL spectacles (Control) for one week each. All subjects wore both Test and Control spectacles, and the pair to be worn first was randomly assigned. At dispensing and after 1 week of wear, subjects were tested for distance and near visual acuity (VA) under both high and low contrast; in addition, 30 degree off-axis VA was measured using a novel apparatus, as was the horizontal extent of undistorted vision at reading distance. Subjects also completed a set of questionnaires detailing their satisfaction levels, adaptation times, and preferences for Test or Control spectacles for different visual tasks.

Inclusion Criteria:

• Presbyope
• Experienced PAL spectacle wearer
• Correctable to at least 20/25 in both eyes
• Able and willing to use Test and Control spectacles for 1 week each as primary form of presbyopia correction
• Able and willing to complete all laboratory measurements and questionnaire batteries

Exclusion Criteria:

• Purchasing free-form PAL spectacles from the UC Berkeley Eyewear Center
• Having eye conditions or diseases that could potentially cause a decrease in visual acuity over the course of participation in the study
• Having eye conditions or diseases that could potentially interfere with ability to use Test and Control spectacles as primary form of presbyopia correction