夜戴“一副到位”角膜塑型镜片对角膜上皮的影响

目的探讨"一副到位"Ortho-k在降低近视屈光度的同时能否保持角膜上皮的健康问题.方法研究142例(292眼)随访4周的Ortho-k治疗患者.根据患者的屈光度、曲率和试戴情况,选用DK值为58,HDS材料的一副镜片,连续夜戴28天,次日及每周给予包括视力、主觉验光、角膜地形图和裂隙灯等眼科检查,比较不同镜片配适与角膜上皮染色的关系.结果戴镜第28天,平均屈光度由治疗前的-4.26D降至-0.80D,裸眼视力提高到0.8以上占85%.治疗中出现镜片过紧等配适变化.同期有不同程度的角膜上皮染色131只眼(占45%),其中出现在镜片过紧组占61%,明显高于活动度正常组中的28%,两组比较差异有显著性意义(P＜0.01).结论速降型Ortho-k能迅速有效地降低近视屈光度,但角膜染色检出率较高,与配适过紧显著相关."一副到位"的"夜戴"形式容易出现配适过紧,影响镜下泪液循环,因缺氧而导致角膜上皮染色.要在提高视力的同时保持角膜上皮健康,必须及时修改、更换镜片,调整配适."一副到位"的提法不宜提倡.

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%) (P<0.01,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]