Myopia Toric Centration Study
Research type
Research Study
Full title
Toric Contact Lenses Non-dispensing Fitting Study
IRAS ID
307099
Contact name
Michel Guillon
Contact email
Sponsor organisation
CooperVision International Limited
Duration of Study in the UK
0 years, 7 months, 17 days
Research summary
Research Summary:
Myopia (short-sight) prevalence is increasing at a very rapid rate amongst children and adolescents due predominantly the rapid change in life style with increasing use of near devices (smartphones, tablets, screens, etc.). To counteract this, special optic contact lenses that control myopia progression have been developed. The aim is to limit the amount of myopia in adulthood, as the higher the myopia the greater is the risk of eye diseases, some sight threatening, later in life.A key characteristics associated with the efficacy of the various contact lens optical designs is that they produce good vision quality for the children and adolescents to wear them most of the day as their main modality of vision correction. An aspect of myopia progression that has been identified in recent times is that the progression is not the same for all parts of the eye resulting in different degrees of myopia called astigmatism, hence the need to correct both myopia and astigmatism in these special optical design contact lenses called toric contact lenses.
The physical design of toric contact lenses differ in part form the standard designs correcting only myopia and a concern is that the centration over the pupil, which affects vision quality, of toric contact lenses may differ from the current design. Hence, prior to developing the new range of toric myopia control contact lens it is important to verify that the contact lens centration and stability is similar to the current lenses in a children / adolescents population.
The aim of the study is, therefore, to fit both simple (spherical) and toric contact lenses to children and adolescent currently wearing contact lens for a short period of time in the clinic to make a video recording of the contact lens fit from which to precisely measure contact lens centration.
Lay summary of study results:
The rationale for the non-dispensing study was to compare the lens fitting characteristics of currently used daily disposable toric contact lenses to that of MiSight® 1-day in the target population.
The efficacy objective of the study was to compare the contact lens centration in primary gaze and downgaze of MyDay® toric, clariti® 1day toric and MiSight® 1-day contact lenses.
The other efficacy aspects of interest were to compare:
i. Contact lens centration following extreme eye movements of MyDay® toric and clariti® 1day toric contact lenses compared to MiSight® 1-day contact lenses;
ii. Toric stability following extreme eye movements of MyDay® toric and clariti® 1day toric contact lenses;
iii. Contact lens movement at blink of MyDay® toric and clariti® 1day toric contact lenses compared with MiSight® 1-day contact lenses;
iv. Lens handling (insertion and removal) of MyDay® toric and clariti® 1day toric contact lenses and MiSight® 1-day contact lenses.
The results are as follows:
i. In primary gaze mean overall decentration were as follows: MiSight = 0.589mm; Clariti Toric = 0.588mm; MyDay Toric = 0.522mm, the differences between MiSight and the test contact lenses being not statistically significant (MiSight vs. Clariti Toric p = 0.986; MiSight vs. MyDay Toric p = 0.652);
ii. In downgaze mean overall decentration were as follows: mean: MiSight = 0.781mm; Clariti Toric = 0.742mm; MyDay Toric = 0.741mm, the differences between MiSight and the test contact lenses being not statistically significant (MiSight vs. Clariti Toric p = 1.000; MiSight vs. MyDay Toric p = 1.000);
iii. In primary gaze immediately prior the blink and initiation of extreme eye movements mean overall decentration were as follows: mean: MiSight = 0.595mm; Clariti Toric = 0.514mm; MyDay Toric = 0.553mm, the differences between MiSight and the test contact lenses being not statistically significant (MiSight vs. Clariti Toric p = 0.741; MiSight vs. MyDay Toric p = 1.000);
iv. In primary gaze immediately after extreme eye movements and one blink mean overall decentration were as follows: mean: MiSight = 0.532mm; Clariti Toric = 0.477mm; MyDay Toric = 0.555mm, , the differences between MiSight and the test contact lenses being not statistically significant (MiSight vs. Clariti Toric p = 0.862; MiSight vs. MyDay Toric p = 0.862);
v. Overall decentration (remained unchanged from pre to post extreme eye movement for all three study contact lenses (p = 0.533 to 1.000);
vi. Contact lens orientation of Clariti Toric and MyDay Toric were similarly good in all test conditions with on average a difference from 90o of less than 3o;
vii. The static contact lens fit judged clinically in terms of contact lens centration and corneal coverage was similar for MiSight and both Clariti Toric and MyDay Toric contact lenses;
viii. The dynamic fit judged clinically in terms of lens movements at blink and push up showed that Clariti Toric and MyDay Toric movements were more frequently optimal than MiSight movements;
Contact lens handling was similarly good for all three study contact lenses.
The study demonstrated that lens centration of the two test toric contact lenses, Clariti Toric and MyDay Toric, was non-inferior to that of MiSight spherical control contact lens in both primary and down gazes supporting the primary hypothesis tested. Additionally, the study demonstrated that: i. lens centration remained unchanged following extreme eye movements for all three contact lenses types; ii. contact lens handling was similarly easy for the test toric contact lenses than for MiSight spherical control.REC name
London - West London & GTAC Research Ethics Committee
REC reference
21/PR/1482
Date of REC Opinion
19 Nov 2021
REC opinion
Further Information Favourable Opinion