A study of accelerated orthokeratology on corneal epithelium health

Objective:This paper investigates whether accelerated Orthokeratology can reduce myopia and still maintain corneal health.Methods:147 young myopic subjects(292 eyes) were fitted with the original optimal choice of overnight wear Ortho k contact lenses in 58 DK material(HDS) based on their corneal curvatures,subjective refractions,and the diagnostic fitting. They wore the lenses for 28 days and were examined the day after removal and then on a weekly basis. At each visit,a full examination was performed including visual acuity,subjective refraction and corneal topography,slit lamp examination,and the relationship between lens fitting and corneal epithelium staining.Results:After wearing the lenses for 28 days,the average subjective refraction was reduced from -4.26D to -0.80D,and unaided visual acuities reached 20/25 or better in 85% of the patients. The change in the lens fitting(most of them became too tight) was observed in the treated eyes,and corneal staining was observed at the same time in the 131 eyes(45%). The incidence of corneal staining in the tight fit group was 61%,significantly higher than in the perfect fit group(28%) (P0.01,Chi square test).Conclusion:Accelerated orthokeratology was found to be effective in reducing myopia and in improving unaided visual acuity at distance. However,during the overnight wear treatment using a single lens fit,the incidence of corneal staining was quite high for the tight lens fitting. Tight lens fitting blocks the exchange of tears under the lens,resulting in corneal hypoxia. Refitting is required to attain good vision and maintain a healthy corneal epithelium. It is not wise to encourage the use of accelerated Ortho k using a singe lens fit. [FK(WB80011?6]