Effect of Defocus in Soft Contact Lenses on Internal Retinal Vascularization

March 26, 2025 updated by: Université de Montréal

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.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

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.

Study Type

Interventional

Enrollment (Estimated)

25

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Quebec
      • Montreal, Quebec, Canada, H3T1P1
        • Université de Montréal

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Myopic defocus soft lens design (MDSL)
This arm involves the wear of a daily disposable soft contact lens (nesofilcon A) designed with a myopic defocus zone. This is a 14.2mm total diameter lens with a 4.2mm central zone for distance vision correction. This is followed by an abrupt transition zone of 1.2mm with no optical power. Then a higher convex power zone covers the surface to the edge of the optical zone (8mm). The rest of the lens (up to 14.2 mmOAD) supports the lens on the eye surface and has no power nor refractive effect. The power of the add area is calibrated to the central power to achieve a net add power of +5D. For example: -1.00D central power is surrounded by a +6D convex area; -2D is surrounded by a +7D area, and so on.)
Device: Experimental: Myopic defocus soft lens design (MDSL)
An optical device designed to provide a myopic defocus to control myopia progression
Active Comparator: Single vision soft lens design (SVSL)
This arm involves the wear of a daily disposable soft contact lens (nesofilcon A) designed as a regular optical device to compensate for refractive error. In the case of this study, this lens will be made available from -1.00D to -4.00D. This lens is already in regular use in the US (K113703) and Canadian markets. Its design includes a central optical zone of 8mm that is powered to correct distance vision. The rest of the lens is supported on the ocular surface and has no power.
Device: Active Comparator: Single vision soft lens design (SVSL
An optical device designed to correct refractive error like myopia

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Measurement of Retinal blood vessel density measured by Triton OCT-A
Time Frame: 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)
Measurement done at baseline and after 1 week of contact lens wear

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Evaluation of the choroidal thickness at the macular area
Time Frame: 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)
Measurement done at baseline and after 1 week of contact lens wear

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Université de Montréal

Collaborators

Bausch & Lomb Incorporated

Investigators

  • Principal Investigator: Langis Michaud, OD MS, Université de Montréal

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 25, 2024

Primary Completion (Actual)

January 31, 2025

Study Completion (Estimated)

March 30, 2025

Study Registration Dates

First Submitted

July 8, 2024

First Submitted That Met QC Criteria

July 24, 2024

First Posted (Actual)

July 30, 2024

Study Record Updates

Last Update Posted (Actual)

March 27, 2025

Last Update Submitted That Met QC Criteria

March 26, 2025

Last Verified

March 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2024-5133

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Study Data/Documents

  1. Study Protocol
    Information comments: Protocol and other documentation available upon request to the principal investigator email

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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