Nearsightedness
Conditions
Keywords
myopia, retinal vasculature, choroidal thickness
Brief summary
The purpose of this study is to gain a better understanding of the retinal vascular changes that occur in response to the optical effect of a myopic defocus daily disposable soft contact lens (MDSL) in a group of healthy young myopic adults (18-35 years; myopia -1.00D to -4.00D; all genders). It will also learn about the acceptance of this visual correction modality compared to regular contact lenses. The main questions to be answered are: * To evaluate changes in retinal blood flow by visualizing retinal vascular density in the superficial and deep plexus after one week of MDSL wear. * To evaluate changes in choroidal thickness at the macular level after one week of MDSL wear. * To evaluate the visual comfort provided by this MDSL design using a questionnaire. Researchers will compare the MDSL to a daily disposable single vision soft lens (SVSL) used to correct myopia to determine if the addition of a defocus area makes a difference in the retinal response to the visual signal. Participants will be required to * Wear both MDSL and SVSL for one week each, in a random order. * Read letters to measure visual acuity * Have a deep scan of their retina with an optical coherence tomography (OCT) device * Rate the comfort and vision provided by both devices using a questionnaire.
Detailed description
Objective: The aim of this study is to gain a better understanding of the retinal vascular changes that occur in response to the optical effect of a myopic defocus daily disposable contact lens used in another (ongoing) research project (NCT05191134). The primary objective of the study is to evaluate changes in retinal blood flow by visualizing retinal vascular density in the superficial and deep plexus following one week's wear of a high peripheral add soft contact lens in a population of young myopic adults. The second objective is to assess changes in choroidal thickness at the macular level after one week's wear of the high peripheral add soft contact lens. A third objective is to evaluate, through questionnaire, the visual comfort provided by this lens design. Materials and methods: 25 myopic participants aged between 18 and 35 will be enrolled. Each participant will be randomly fitted with two lenses: a monofocal spherical soft lens (nesofilcon A) for one week and a high-add bifocal soft lens (anti-myopia) for the same duration of time. Participants will be asked to attend three different visits, one week apart. At visit #1, initial measurements of deep and superficial plexus blood vessel density and choroidal thickness will be taken with an angiographic optical coherence tomograph (OCT-A Triton, Topcon USA). These measurements will be repeated with other lenses at visit 2 and 3. The results will be compared. Participants will be asked to evaluate the visual performance of each lens after 1 week of wear through a questionnaire. Hypothesis: It is expected that one week's wear of the peripheral myopic defocus contact lens will cause an increase in blood vessel density and a thickening of the choroid compared with initial measurements. A decrease in blood vessel density and choroidal thinning is expected after one week's wear of the spherical soft lens (hyperopic defocus), compared with baseline. Both lenses will be well tolerated during daily activities.
Interventions
DEVICEExperimental: Myopic defocus soft lens design (MDSL)
An optical device designed to provide a myopic defocus to control myopia progression
DEVICEActive Comparator: Single vision soft lens design (SVSL
An optical device designed to correct refractive error like myopia
Sponsors
Bausch & Lomb Incorporated
Université de Montréal
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Masking description
The lenses used in this study are daily disposable. This means that for each type of lens worn, participants will receive 7 lenses of each type. Lenses will be delivered one type at a time for the next week. The lenses will be packaged with a neutral label with a lot number. It is impossible for the participant to know which type this lot number corresponds to. Therefore, they do not know what type of lens they will receive.
Intervention model description
Prospective, randomized, crossover masked study. Participants are randomly assigned to wear one type of soft lens for one week, then washed out for a few days, and then the second type of soft lens for the same period of time. Participants are masked to the type of lens provided
Eligibility
Sex/Gender
ALL
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* · Astigmatism ≤ 1.00 D * Myopia between -0.50 and -4.00D * Aged between 18 and 35 * Binocular acuity of 6/6 or better
Exclusion criteria
* · Recent intake (\< 3 months) of medication affecting blood pressure (e.g. hypotensive, anovulant, CNS stimulant, etc.). * Corneal dystrophy or irregularity * Use of topical ocular medications * Smoking (tobacco or marijuana) * Have contraindications to wearing soft contact lenses * Being currently under myopia control treatment or had been under control in the last 3 months * Being pregnant or breast-feeding * History of refractive surgery * Addiction to drugs or alcohol
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Measurement of Retinal blood vessel density measured by Triton OCT-A | Measurement done at baseline and after 1 week of contact lens wear | The TRITON angiographic optical coherence tomograph will be used in this research project. OCT-A is a non-invasive angiography that enables changes in retinal vascularization to be observed. This is achieved by analyzing the movement of erythrocytes in blood vessels using a series of B-scans. Retinal vessel density will be measured at the macular area and at the optic nerve head. (2 scans) |
Other
| Measure | Time frame | Description |
|---|---|---|
| Evaluation of the choroidal thickness at the macular area | Measurement done at baseline and after 1 week of contact lens wear | A 3D scan (OCT- Heidelberg) 6.0mm x 6.0mm will be performed for analysis of choroidal thickness in the different ETDRS quadrants. Choroidal thickness data per quadrant (1-5) will be available in the 6mm CSI analysis (BM-CSI) |
Countries
Canada
Outcome results
None listed