Assessment of the Relationship of Soft Contact Lens Fit and Power (Fit & Lens pOwer Soft lenSes) (FLOSS)

Evaluation of the Vision and Fit of Commercially Available Correct Powered (Prescription) Contact Lenses Compared to Lenses Within a Range of ± 2.00 Dioptres (Strength/Power of Lens) From the Prescription

The purpose of this study is to evaluate whether altering the optical power (in dioptres) of a contact lens affects both vision and lens fit. As the majority of modern contact lens wearers prefer daily disposable soft lenses, the trial lenses used in this study-provided by CooperVision-reflect this trend, representing nearly 80% of the current UK market.

This study aims to generate data supporting the use of contact lenses with powers that do not precisely match a participant's visual prescription (within ±2.00 dioptres) as a viable temporary alternative when the exact required power is unavailable.

At present, there is no published literature in the context of modern contact lens design that compares the fitting characteristics of 'fit-for-purpose' lenses with those of lenses from the same design family that would not typically be selected due to power mismatch.

Study Overview

• Status: Enrolling by invitation
• Conditions: Contact Lens Wear; Healthy Participants Study; Contact Lens Fit
• Intervention / Treatment: Device: contact lens wear

Detailed Description

This study aims to evaluate the vision and fit of commercially available prescription contact lenses of different strengths to determine whether this affects the final lens selection and, if so, how. In addition, the study will compare subjective comfort and key fitting criteria such as centration, movement, tightness, coverage, and overall impression.

These data could help eye care practitioners use lenses they already have in stock instead of ordering new ones and requiring patients to return. Understanding whether these lenses fit similarly could make the process more convenient for both patients and practitioners. Patients would receive their lenses more quickly, and eye care providers could manage their existing stock more effectively.

The two visits will take place at the Aston University Eye Clinic. Data collection and assessments will include:

Participant's age, ethnicity, sex, and ocular history to determine eligibility [recorded electronically on a secure computer].

A standardised OSDI questionnaire (paper copy only), which quantifies dry eye symptoms, severity, and frequency (e.g. in the past week, how often participants' eyes felt gritty, watery, itchy, or burning, and how many times they experienced these symptoms), will be administered at the first visit after written consent. The completed questionnaire will be scanned and uploaded to BOX.

Both Visit One and Visit Two will include:

Application of contact lenses to the participant's eyes. Lens powers will be randomised between visits for each participant.

Comfort assessment using:

A visual analogue scale (paper-based) from "most comfortable" to "least comfortable," where participants mark their comfort level.

A numerical rating (1-10) of comfort, recorded electronically. Vision assessment after lens application, both objectively (autorefractor) and subjectively, as in routine clinical practice.

A video-recorded ocular assessment of the contact lens fit, including horizontal lens movement, blink-induced movement, and lens centration.

After data collection is complete and the lenses are removed at Visit Two, participants will be asked which lenses they preferred [recorded electronically].

The data collection follows standardised contact lens assessment protocols used in both primary and secondary care optometry.

A participant's current eye care practitioner will not be informed of their participation or the corresponding assessments/data unless clinically significant findings are discovered and the participant consents to sharing this information. Participants will be informed of the lens brand and manufacturer used in the study so that, if they find the lenses more comfortable than their current ones (if applicable) or are considering contact lenses, they may discuss this with their eye care practitioner.

• Study Type: Interventional
• Enrollment (Estimated): 38
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • UK
    • Birmingham, UK, United Kingdom, B4 7ET
      • School of Optometry, Aston Eye Clinic

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Between 18-60 years of age
• Vision correctable to at least 6/12 (20/40) or better in each eye
• with mental capacity to provide written consent in English (as per the Mental Capacity Act, 2005).
• happy to wear investigational contact lenses

Exclusion Criteria:

• Any active infection or inflammation, history of major systemic or ophthalmic conditions
• use of systemic or topical medications known to affect the eye in the previous 3 months
• history of ocular surgery, currently enrolled on another study/clinical trial that may impact outcome
• any other contraindications for typical contact lens wear
• As per the Mental Capacity Act, 2005, participants will be automatically excluded if not deemed to have Capacity for consent or under the age of 18.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Healthy participants; All healthy participants wear two different contact lenses, one with the correct power and one with +/- 2.00 Ds to actual refraction. All lenses are commercially available. No 2nd arm.	Device: contact lens wear; participants wear two different powered contact lenses (one with actual power, and one +/- 2.00Ds) contact lenses. No 2nd arm

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Soft contact lens horizontal lag:Subjective and objective assessment of soft contact lens lag.	Lens lag will be graded as: <50% lag = less leg, 50% to 100% is optimum lag, >100% = high lag.	within 30 mins of lens wear
Soft contact lens tightness: graded subjectively as optimum, loose and tight	Soft contac tlens tightness	within 30 mins of lens wear
Soft contact lens movement: Subjective and objective assessment of soft contact lens movement.	Lens movements will be graded between 0.25 - 0.50 mm = Optimum, <0.25 = Less movement; >0.50mm is more movement.	within 30 mins of lens wear

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Assessment of ocular comfort with soft contact lenses	Ocular comfort is graded by particpants 1-10 (1 being very uncomfortable and 10 being highly comfortable)	within 30 mins of lens wear

Collaborators and Investigators

• Sponsor: Aston University
• Collaborators: CooperVision, Inc.

Study record dates

Study Major Dates

• Study Start (Estimated): January 30, 2026
• Primary Completion (Estimated): August 31, 2026
• Study Completion (Estimated): December 31, 2026

Study Registration Dates

• First Submitted: December 9, 2024
• First Submitted That Met QC Criteria: December 19, 2024
• First Posted (Actual): December 20, 2024

Study Record Updates

• Last Update Posted (Actual): January 21, 2026
• Last Update Submitted That Met QC Criteria: January 19, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: contact lens; contact lens wear; contact lens fit
• Additional Relevant MeSH Terms: Equipment and Supplies; Optical Devices; Lenses; Contact Lenses, Hydrophilic; Contact Lenses; Contact Lenses, Extended-Wear
• Other Study ID Numbers: HLS21201

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: This has not been planned, yet but there is no reason cant be done by the end of study.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No