This clinical study aims to understand how glasses with a small reading addition affect the way the eyes focus and work together in young adults with normal near vision.
Some people experience focusing difficulties or visual discomfort during near-vision activities such as reading or using digital devices. This study will evaluate whether glasses with a small reading addition can help reduce these difficulties and improve visual comfort.
Researchers will compare two different pairs of glasses designed to provide additional support for near vision. They will assess how each pair affects eye focusing and eye coordination using standard optometric examinations.
Participants will:
* Wear three pairs of glasses, each for approximately 4 weeks. * Complete eye examinations to evaluate focusing ability and eye coordination. * Answer questionnaires about visual comfort, eye strain, and overall quality of vision.
1.Voluntary person, fluent in English willing to follow the protocol, able to read and understand the information form and give his free and informed consent
2.Aged between 18 and 35 years old
3.Non-presbyopic
4.Wears glasses for at least 6 hours per day
1.Pregnant woman or nursing
2.Persons deprived of their liberty by a judicial or administrative decision and persons hospitalized without consent and persons admitted to a health or social institution for purposes other than research
3.Adults who are unwilling or unable to express consent
4.Participant in exclusion period from another study
Crossover
Eye exam
DeviceAn optometric eye exam
Questionnaires
Other interventionQuestionnaires on the eye fatigue and the quality of vision
Washout lenses
DeviceStandard single-vision spectacle lenses prescribed according to each participant's refractive error and worn during the washout period before allocation to the study lenses.
Reference lenses
DeviceSpectacles lenses optimized near vision lenses for the comparator
Test lenses
DeviceSpectacles lenses optimized near vision lenses for the test
Accommodative facility difference
Measurement of the accommodative facility to understand the flexibility of the accommodation. It will be measured in cycle per minute (cpm) using a +/-2.00D flipper lens test at 40cm according to standard clinical accommodative facility testing procedures. Lenses are placed in front of the eyes to stimulated or not the accommodation on a text. The main goal of the participant is to keep clear and single the target while switching between the accommodative lenses and the non accommodative lenses. The results obtained after the wearing period of each lenses will be compared together.
Visual fatigue questionnaire score
Visual fatigue assessed using a validated questionnaire, CISS (Borsting et al, Optometry and Vision Science. 2003, 80(12):832-838). Total questionnaire scores (range 0 to 56 with a higher score meaning a higher fatigue) obtained after each lens-wear period will be compared between the reference lens and the test lens
Visual Comfort Questionnaire Score
Visual comfort assessed using a questionnaire administered at the end of each lens-wear period. Questionnaire scores (range from 0 to 182) will be compared between the reference lens and the test lens.
Vision Quality Questionnaire Score
Subjective quality of vision assessed using a questionnaire. Total questionnaire scores (range from 0 t o182) will be compared between the reference lens and the test lens.
Participant Lens Preference
Participant preference for the reference lens or the test lens assessed at the completion of both lens-wear periods using a preference questionnaire.
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