Possible effect of induced higher order aberrations (HOA) on myopia control by orthokeratology

Session Details

Session Title: Advanced Tools for Outcome Assessment

Session Date/Time: Tuesday 17/09/2019 | 08:30-10:30

Paper Time: 08:42

Venue: Free Paper Forum: Podium 4

First Author: : A.Kovalov UKRAINE

Co Author(s): :    O. Averyanova   I. Kovalov                          

Abstract Details

Purpose:

To evaluate induced HOA at the time of orthokeratology correction of myopia in teenage group of patients and possible influence on the myopia control (stabilisation or slowing the progression).

Setting:

AILAS Medical Center, Kyiv, Ukraine.

Methods:

50 Myopic patients (100 eyes) age 10–18 years (mean 14.2 ± 2.8) were corrected by Paragon CRT Lenses. Standard examinations including BUVA, BCVA, refraction, U/S Biometry, Corneal Topography and Aberrometry were done at the beginning (base line), 1, 3, 6, 12 and 24 months after the beginning of Ortho-K Treatment. Mean initial refraction was Sph: (-)3.71 ± 1.27D, Cyl: (-)0.62D ± 0.41D. Mean HOA (rms) (6.0mm pupil) were 0.346 ± 0.171µµ., Mean Spherical HOA (SA): 0.024 ± 0.011µµ. Mean accommodative reserve of the ciliary muscle was 2.7 ± 1.8 D. All patients finished 24 months of followup.

Results:

After 1 month of therapy all patients got stable refraction (mean: Sph (+) 0.11 ± 0.12D), BUVA 20/20 or better, stable keratometry and corneal topography. None of the patients progressed for more than (-)0.5D/year. Total HOA increased: (mean) to 1.022 ± 0.205µµ, SA – 0.22 ± 0.087µµ. All induced SA were positive. Mean accommodative reserve of the ciliary muscle increased to 6.9 ± 1.4D, and became comparable with the age norm. No significant complications occurred at the time of follow up.

Conclusions:

Ortho-K treatment is safe and effective in correcting and stabilizing the myopia in teenage group of patients. Myopia control (stabilization) in this group of patients is associated with the increasing strength of ciliary muscle. Positive SA are shifting the best image plain (focus) of the eye towards myopia. At the time of accommodation the pupil constricts (accommodative miosis). With constricted pupil the level of HOA (including SA) decreased. Focus is shifted towards hyperopia. Ciliary muscle has to constrict more for the accommodation. This mechanism can be responsible for the increasing of ciliary muscle increasing strength and myopia control.

Financial Disclosure:

None