This article was originally published in a sponsored newsletter.

Although the scleral lens category continues to grow, the number of multifocal scleral lens fittings are a small percentage of the category as a whole.¹

A recent study postulated that a novel multifocal scleral lens design with decentered optics could deliver improved optical and visual quality results.² This study evaluated the quality of vision of a new multifocal scleral lens with a modified decentered optic zone compared to a conventional design. The custom design incorporated a decentered optical zone from the geometrical center of the lens that was centered on the patient’s pupil.

After one month of scleral lens wear in 19 patients who had presbyopia, visual acuity, contrast sensitivity function, stereopsis, comfort, and subjective vision were evaluated. Patients had a mean age ranging from 47 to 60 years (51.7 ± 3.9 years).²

Generally, based on ocular shape, scleral lenses tend to decenter intertemporally, leading to a misalignment between the visual axis and the optics of the lens.³ There are myriad reasons for this misalignment, which contain factors such as the lens thickness, scleral topography, post-lens fluid reservoir, and the force applied by the eyelids.⁴ Thus, the post-lens fluid reservoir thickness is not uniform, creating a prismatic effect on vision due to the position of the center of a scleral lens with respect to the visual axis.^5,6 Higher-order aberrations (HOAs) may contribute to decreased visual performance, predominantly horizontal and vertical coma, which are not corrected with the tear meniscus.⁵

Each patient wore a conventional and decentered lens design, for one month each, including a two-week washout period. At the initial lens fitting with respect to the pupil center, the average lens decentration was 0.34mm ± 0.24mm inferiorly and 0.24mm ± 0.24mm temporally, with maximum values of 0.79mm inferiorly and 0.62mm temporally.

There were not any differences between lens designs for distance vision with varied lighting conditions according to binocular defocus curves. There was a slight improvement in near vision, specifically under photopic conditions with the decentered lens design. Although there was an improvement of one line (6 letters) for the −3.00D vergence, which may be clinically relevant, the amount of improvement was not statistically significant.

With decentered optics lenses, the visual analog scale (VAS) questionnaire scores demonstrated a significant improvement in distance and overall subjective vision. Additionally, with decentered optics lenses, contrast sensitivity function showed an enhancement at all measured spatial frequencies and were statistically significant for 12 cycles per degree. There were not any differences in stereoacuity with either lens design.

A limitation of this study is that both lens designs were not evaluated in a random order; for all patients, the conventional design was always tested prior to the decentered lens design, which may affect the results of the study. Also, due to the small sample size, the use of near adds were only up to +2.25D. Future studies may be beneficial.

A multifocal scleral lens with decentered optics may be a useful solution to improve vision and comfort in scleral lens wearers.

Reference(s):

1. Nichols JJ, Fisher D. Contact Lenses 2023. Contact Lens Spectrum. 2024 Jan/Feb;39:14-16,18,19.
2. Privado-Aroco A, Romaguera M, Valdes-Soria G, Serramito M, Carracedo G. Visual quality assessment and comparison of two multifocal scleral lens designs. Cont Lens Anterior Eye. 2024 Feb;47:102098.
3. Fadel D. Modern scleral lenses: Mini versus large. Cont Lens Anterior Eye. 2017 Aug;40:200-207.
4. Kowalski LP, Collins MJ, Vincent SJ. Scleral lens centration: The influence of centre thickness, scleral topography, and apical clearance. Cont Lens Anterior Eye. 2020 Dec;43:562-567.
5. Vincent SJ, Fadel D. Optical considerations for scleral contact lenses: A review. Cont Lens Anterior Eye. 2019 Dec;42:598-613.
6. Vincent SJ, Alonso-Caneiro D, Collins MJ. The temporal dynamics of miniscleral contact lenses: Central corneal clearance and centration. Cont Lens Anterior Eye. 2018 Apr;41:162-168.

Melissa Barnett, OD, FAAO, FSLS is the director of optometry at the University of California, Davis, and the host of the “Clearly KC” podcast. She has received remuneration from ABB, Acculens, Allergan, Azura, Bausch + Lomb, BCLA, Bruder, CooperVision, Dompé, JJVC Vistakon, Lentechs, Ocusoft, Orasis, Oyster Point, Percept, RVL, Sight Sciences, Science Based Health, Scleral Lens Education Society, STAPLE Program, Sun Pharma, Taursus, Visus, and Vyluma.