• Journal of Korean Ophthalmic Optics Society
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• v.14 no.3
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• pp.7-15
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• 2009

Purpose: To investigate the corneal recovery after discontinuing orthokeratology (OK) lenses wear in children for long-term period. Methods: Among the OK lens wearers who wear over 8 months and showed successful refractive correction, 25 subjects were selected who want to discontinue the OK lenses. Uncorrected visual acuity, refractive correction, corneal curvature (Sim K), central corneal thickness and corneal eccentricity were measured during the OK lens wearing period and after discontinuation for 1 month. Results: Uncorrected visual acuity and corneal shape had remodeled significantly during the OK lens wear and recovered significantly during the first week of discontinuation. Uncorrected visual acuity and refractive correction had achieved full recovery 2 weeks after discontinuation of lens wear and were highly correlated with the changes in corneal thickness. But corneal shape recovered slowly, eccentricity had recovered fully after 1 month and corneal curvature and central thickness had not been achieved full recovery until 1 month after discontinuation. Conclusions: Recovery of after longterm use of OK lens is rapid for refractive change, but slow for corneal curvature and central thickness that to refit the contact lenses, practitioners need patience.

• Journal of The Korean Ophthalmological Society
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• v.59 no.11
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• pp.1009-1016
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• 2018

Purpose: To assess the effect on axial elongation and associated factors between spectacles and of orthokeratology lens (OK) wearing in children with mild to moderate myopia. Methods: A total of one hundred subjects, ranging in age from 6 to 13 years, and with mild to moderate myopia no more than -4.50 diopters in spherical equivalent, visited our clinic from 2013 to 2015. The OK group (75 eyes) and the spectacles group (64 eyes) were compared and analyzed on the axial elongation and associated factors. Results: In the OK group, axial length was elongated in 1 year period with a mean increase of $0.24{\pm}0.29mm$. In spectacles group, axial length was elongated in 1 year period with a mean increase of $0.42{\pm}0.20mm$. The statistically significant suppression of axial elongation was observed in OK group compared to the spectacles group (Mann-Whitney U test, p < 0.05). For OK group, the age of starting OK (Pearson's correlation, r = -0.481, p < 0.05) was the only influencing factor on axial elongation, which had negative correlation with axial elongation. In spectacles group, the age of starting spectacles had negative correlation with axial elongation (Pearson's correlation, r = -0.462, p < 0.05) and baseline spherical equivalent, spherical diopter, cylindrical diopter from manifest refraction had positive correlation with axial elongation. Comparison of axial elongation in orthokeratology lens group and spectacles group by age groups (6 to 9 years [28 eyes], 9 to 13 years [47 eyes]), 9 to 13 years of orthokeratology lens group had the stronger suppression of axial elongation (Mann-Whitney U test, p < 0.05). Conclusions: The OK effectively suppresses axial elongation compared to the spectacles. Although the patients are in age from 9 to 13 years, the axial elongation was effectively suppressed.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.2
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• pp.1-12
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• 2007

Object of this research is to estimate the effect of myopia correction and safety on reverse geometry contact lens fitting in school children. This research include 53(106eyes) schoolchildren among 7 to 18 years who has low to moderate myopia(-1.00D~-5.00D) and prescribed reverse geometry contact lens for purpose on orthokeratology between January to July 2004 and had 3months full follow up examination. They were tested for slit lamp examinations, BUT(Break up time), direct ophthalmoscopy, retinoscopy, uncorrected visual acuity, best corrected visual acuity, autorefraction, autokeratometry and corneal topography in each examination(1day, 1week, 2weeks, 1, 2, and 3months) of before-and-after lens wearing to find out the effect of myopic correction and side effect. The results came out as follow. The average of uncorrected visual acuity was $0.0938{\pm}0.378$ before lens wear and $0.3136{\pm}0.283$ after 1day lens wear, and there was fast improvement after 1week($0.7925{\pm}0.301$) and little improvement after 2weeks period but still they shows better uncorrected visual acuity(p<0.01). The result of this study, the reverse geometry lens is very useful to correct refractive error and control the progression of myopia temporally among low to moderate myopic patient. The side effects were relatively rare but further study should be necessary with long term lens wear effect on eye health. For the lens prescription, the clinical fitting process had higher rate of success with consideration of eccentricity and corneal topography.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.271-277
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• 2013

Purpose: The purpose was to study the corneal refractive power changes associated with the wearing of everted silicone hydrogel soft lenses. Methods: The corneal refractive power and corneal astigmatism were measured using corneal topographer (CT-1000, Shin-nippon Co., Japan) for checking change of corneal refractive power and objective refractive error was measured by auto-refractometer (Natural vision-K 5001, Shin-nippon Co., Japan). We measured at baseline and 1 week after lens wearing. Results: The correcting of corneal refractive power could be effective in low myopia. It's more effective to the higher power of greatest meridian of cornea and the more corneal astigmatism. 73% of subjects' refractive error was decrease less than 1 D and 17% of the subjects had an reverse effect (increase) occurs. The reduction of objective refractive error was more effective when cornea refractive power was great or corneal astigmatism was much. Conclusions: Pressure which the everted silicone hydrogel lens to the cornea could be caused. It occurred as the degrees of corneal power, corneal astigmatism and objective refractive error differences. Selection of an appropriate subject is important considering difficulty of changing the parameters of the lens.