Effect on the accommodation function of monocular orthokeratology in anisometropic children

Abstract:

AIM: To observe the changes of binocular eye accommodation function in correcting anisometropia by monocular orthokeratology in anisometropic children, and to explore the mechanism of regulation in the progression of myopia control by orthokeratology.

METHODS: It was a prospective self-control study. A total of 22 anisometropic children(44 eyes), aged 8-13 years, who wore an orthokeratology lens in only one eye were enrolled in the outpatient clinic of Hainan Provincial Eye Hospital from September 2016 to September 2018. The eyes with an orthokeratology lens had a mean spherical equivalent refraction of -2.751±1.16 diopter(D), and fellow eyes without a lens had a refraction of -0.10±0.32D. The eyes wearing orthokeratology lens were used as the lens wearing group, and the fellow eyes without a lens were used as non-wearing lens group. During the follow-up period,we measured changes of diopter difference, monocular accommodative amplitude(MAA), monocular accommodative facility(MAF)and accommodative response(AR)before wearing the lens and wearing the lens for 12mo.

RESULTS: The monocular accommodative amplitude and monocular accommodative facility of the wearing group before wearing the lens were lower than those of the non-wear group(P<0.01), and the accommodative lag were higher than that of the non-wear group(P<0.05). The monocular accommodative amplitude 15.63±1.66D after wearing the lens for 12mo was higher than that before wearing the lens 11.25±3.15D(t=3.63, P<0.01), and the difference was not statistically significant(t=0.75, P=0.46)compared with the non-wearing group. The monocular accommodative facility 14.63±1.58 cyc/min after wearing the lens for 12mo was higher than that before wearing the lens 9.25±3.38cyc/min(t=2.83, P=0.01), and the difference was not statistically significant(t=0.38, P=0.71)compared with the non-wearing group. The accommodative lag 0.62±0.29D of the wearing group after 12mo was reduced compared with that before wearing the lens 1.35±0.26D(t=2.57, P=0.02),and compared with the non-wearing group, the difference was not statistical significance(t=0.61, P=0.55). The mean equivalent diopter of the non-lens group was -0.75±0.35D after 12mo, and the number of diopter group increased by -0.65±0.39D(t=4.24, P<0.01). The diopter of the wearing group increased by -0.15±0.22D(t=2.90, P<0.001), there was a statistically significant difference in the change of diopter between the two groups(t=5.30, P<0.01). There was no statistically significant difference in the change of the accommodation before and after 12mo in the non-wear group(P>0.05).

CONCLUSION: The accommodation function of anisometropic children in correcting anisometropia by monocular orthokeratology was significantly improved compared with that before wearing the lens and was consistent with the contralateral eyes without lens group. The refractive state of the group wearing orthokeratology lens was more stable, and the contralateral eyes without lens gradually showed mild myopia refractive state, but the accommodation did not change significantly.

Key words:anisometropia; orthokeratology; accommodation; monocular; myopia control