Can multifocal lens wear impact accommodative function?

Paper title: Accommodation in Children after 4.7 Years of Multifocal Contact Lens Wear in the BLINK Study Randomized Clinical Trial

Authors: Chandler, Moriah A (1); Robich, Matthew L (2); Jordan, Lisa A (2); Mutti, Donald O (2); Bernsten, David A (1); Fenton, Rachel (2); Day, Elizabeth (2); Walline, Jeffrey J; BLINK2 Study Group

1. University of Houston College of Optometry, Houston, Texas
2. The Ohio State University College of Optometry, Columbus, Ohio

Date: July 2023

Reference: Chandler MA, Robich ML, Jordan LA, Mutti DO, Berntsen DA, Fenton R, Day E, Walline JJ; BLINK2 Study Group. Accommodation in Children after 4.7 Years of Multifocal Contact Lens Wear in the BLINK Study Randomized Clinical Trial. Optom Vis Sci. 2023 Jul 1;100(7):425-431

[Link to open access paper]

Studies investigating accommodative changes in pre-presbyopic adults have found either small accommodative leads or lags when wearing multifocal contact lenses.^1,2,3 For children wearing multifocal contact lenses for myopia control, the accommodative responses have been shown to be similar to, or less than, that seen with single vision lenses.^4,5,6 However, there is little data available on long-term effects on the accommodative system from prolonged multifocal contact lens myopia treatment wear.

The original Bifocal lenses In Nearsighted Kids (BLINK) study compared accommodative responses over 3yrs for single vision and multifocal contact lens wearers (+1.50D add and +2.50 add powers). It investigated myopia progression and eye growth in children (n = 294 aged 7-11yrs with myopia between -0.75 to -5.00D) randomly fit with either Biofinity single vision or Biofinity centre-distance (CD) multifocal contact lenses with +1.50D or +2.50D add powers (Coopervision).  Accommodative responses (AR) were found to be similar for the +1.50 and +2.00D add groups during the first 2yrs. However, at the final visit, lower AR was seen in the +2.50D add group than in both the single vision and +1.50D groups.

The BLINK2 study (n = 248, 84% of the original BLINK trial cohort) aimed to investigate accommodative amplitude, lag and facility differences between the 3 groups after a longer period. It only commenced once the last participant had completed the original BLINK study, meaning some participants continued wearing their allocated lens type for varying periods of time. Accommodative amplitude, lag and facility were measured objectively at baseline using ±2.00D flippers. The findings for each group after an average wear period of 4.7yrs were compared and adjusted for clinic site, sex and age group (7-9 or 10-11yrs).

No statistically significant differences were found between the 3 groups at baseline, other than the +2.50D add power lens group showing shorter axial lengths and less myopia at the start of BLINK2 due to the myopia control effects of the higher add power in the BLINK trial. The unadjusted average values for accommodative amplitude, lag and facility were 5.63D, 1.70D and 9.39 cycles per minute, respectively. After adjustment, no clinically significant differences were found due to clinical site, sex or age group.

The BLINK2 study has shown that despite +2.50D add power centre-distance multifocal lenses giving a reduced accommodative response compared to single vision lens wear over 3yrs in the BLINK trial, this did not extend to issues with accommodative amplitude, lag and facility over an extended period of wear.

These results confirm those found from a contralateral eye study that also investigated long-term multifocal use.⁴ The authors found that dual focus lenses allowed for normal accommodative function for near targets and suggested the wearers were not using the add power to reduce their accommodative efforts. Another study found that although accommodation responses may be reduced in young adult myopes wearing aspheric multifocal contact lenses, this is more likely to be due to multifocal lens design rather than add power.⁸

• Children in the BLINK and BLINK2 studies may be maintaining normal accommodative states for the same reason.

Eyecare practitioners can feel confident that prescribing higher add CD multifocal lens powers for their patients will not cause them long-term accommodative problems.

Although this study found the amplitude of accommodation to be unaffected by long-term multifocal lens wear, the value was found to be lower than that in 2 other studies.^3,5 This may be due to measuring amplitude of accommodation objectively, rather than subjectively which is thought to over-estimate the measurement.⁷

Future studies investigating long-term wear effects for children wearing multifocal contact lenses intended for myopia control could measure all aspects of their accommodative function throughout a full study period.

This could determine short-term only effects we might expect to see as part of the treatment process and not due to permanent changes in the accommodative status of the wearer.

Title: Accommodation in Children after 4.7 Years of Multifocal Contact Lens Wear in the BLINK Study Randomized Clinical Trial

Authors: Moriah A Chandler, Mathhew L Robich, Lisa A Jordan, Donald O Mutti, David A Bernsten, Rachel Fenton, Elizabeth Day, Jeffrey J Walline; BLINK2 Study Group

Purpose: When worn for myopia control in children, soft multifocal contact lenses with a +2.50 D add reduced the accommodative response over a 3-year period, but wearing them for more than 4 years did not affect accommodative amplitudes, lag, or facility.

This study aimed to compare the accommodative response to a 3D stimulus between single-vision, +1.50-D add, and +2.50-D add multifocal contact lens wearers during 3 years of contact lens wear and then to compare accommodative amplitude, lag, and facility between the three groups after an average of 4.7 years of wear.

Methods: Bifocal Lenses In Nearsighted Kids study participants aged 7 to 11 years old were randomly assigned to wear single-vision, +1.50-D add, or +2.50-D add soft contact lenses (CooperVision, Pleasanton, CA). The accommodative response to a 3D stimulus was measured at baseline and annually for 3 years. After 4.7 years, we measured objective accommodative amplitudes, lead/lag, and binocular facility with ±2.00-D flippers. We compared the three accommodative measures using multivariate analysis of variance (MANOVA), adjusting for clinic site, sex, and age group (7 to 9 or 10 to 11 years).

Results: The +2.50-D add contact lens wearers exhibited lower accommodative response than the single-vision contact lens wearers for 3 years, but the +1.50-D add contact lens wearers exhibited only lower accommodative response than did the single-vision contact lens wearers for 2 years. After adjustment for clinic site, sex, and age group, there were no statistically significant or clinically meaningful differences between the three treatment groups for accommodative amplitude (MANOVA, P = .49), accommodative lag (MANOVA, P = .41), or accommodative facility (MANOVA, P = .87) after an average of 4.7 years of contact lens wear.

Conclusions: Almost 5 years of multifocal contact lens wear did not affect the accommodative amplitude, lag, or facility of children.

[Link to open access paper]