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

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

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

Conditions
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Presbyopia

Intervention / Treatment
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* Device: Standard, non-free-form, non-customized PAL spectacles
* Device: Individually customized free-form surfaced PAL spectacles


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 39 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Randomized Order of Interventions 1<br>Randomized to first wear standard, non-free-form, non-customized PAL spectacles, then second, crossover to wear individually customized free-form surfaced PAL spectacles | Device: Standard, non-free-form, non-customized PAL spectacles<br>* Control spectacles include several different PAL brands as selected by patients in the UC Berkeley Optometry Clinic and purchased in the Eyewear Center; after successful fitting and purchase, potential subjects were recruited for the trial.<br>Device: Individually customized free-form surfaced PAL spectacles<br>* Test spectacles are Zeiss Individual, free-form surfaced, and customized using the iTerminal device to account for individual back vertex distance, wrap angle and pantoscopic tilt<br>* Other names: Zeiss Individual, Carl Zeiss Vision, Inc., Germany;|
| Active Comparator: Randomized Order of Interventions 2<br>Randomized to first wear individually customized free-form surfaced PAL spectacles, then second, crossover to wear standard, non-free-form, non-customized PAL spectacles | Device: Standard, non-free-form, non-customized PAL spectacles<br>* Control spectacles include several different PAL brands as selected by patients in the UC Berkeley Optometry Clinic and purchased in the Eyewear Center; after successful fitting and purchase, potential subjects were recruited for the trial.<br>Device: Individually customized free-form surfaced PAL spectacles<br>* Test spectacles are Zeiss Individual, free-form surfaced, and customized using the iTerminal device to account for individual back vertex distance, wrap angle and pantoscopic tilt<br>* Other names: Zeiss Individual, Carl Zeiss Vision, Inc., Germany;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Visual Acuity, High Contrast, Distance Chart | Standard assessment of high contrast visual acuity at distance, as in normal clinical practice, using Baily-Lovey charts and the M&S Technologies Smart System II visual acuity projection system. | Post-1 week of wear of Test Spectacles and post-1 week of wear of Control Spectacles | 
| Visual Acuity, Low Contrast, Distance Chart | Standard assessment of low contrast visual acuity at distance, as in normal clinical practice, using Baily-Lovey charts and the M&S Technologies Smart System II visual acuity projection system. | Post-1 week of wear of Test Spectacles and post-1 week of wear of Control Spectacles | 
| Visual Acuity, High Contrast, Near Chart | Standard assessment of high contrast visual acuity at near, as in normal clinical practice, using Baily-Lovey charts and the M&S Technologies Smart System II visual acuity projection system. | Post-1 week of wear of Test Spectacles and post-1 week of wear of Control Spectacles | 
| Visual Acuity, Low Contrast, Near Chart | Standard assessment of low contrast visual acuity at near, as in normal clinical practice, using Baily-Lovey charts and the M&S Technologies Smart System II visual acuity projection system. | Post-1 week of wear of Test Spectacles and post-1 week of wear of Control Spectacles | 
| 30-degree Off-axis Distance Visual Acuity, High Contrast Chart | Measured with subject immobilized in specially designed apparatus, keeping head pointed straight forward and moving only the eyes to left or right to view the off-axis chart | Post-1 week of wear of Test Spectacles and post-1 week of wear of Control Spectacles | 
| 30-degree Off-axis Distance Visual Acuity, Low Contrast Chart | Measured with subject immobilized in specially designed apparatus, keeping head pointed straight forward and moving only the eyes to left or right to view the off-axis chart | Post-1 week of wear of Test Spectacles and post-1 week of wear of Control Spectacles | 
| Horizontal Extent of Undistorted Vision at Reading Distance | Novel apparatus designed to immobilize head and allow subject to indicate point of peripheral optical distortion on a modified Amsler-type grid | Post-1 week of wear of Test Spectacles and post-1 week of wear of Control Spectacles | 
| Questionnaire Battery | Forced-choice Likert scale preference questionnaire | At study exit, after both Test and Control spectacles had been worn for 1 week each | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Presbyopia, Progressive addition lenses, Customized free-form, Bifocals, Subjective assessment, Visual performance, Visual acuity, Amsler grid