The Evaluation of the Difference between the Calculated Estimated Post-operative Refraction and the Real Post-operative Refraction for Five Types Intraocular Lenses

PURPOSE: To evaluate and compare the difference of predictive post-operative refraction preoperatively and real post-operative refraction among five types of intraocular lens. METHODS: We reviewed retrospectively 567 cataractous eyes that had undergone phacoemulsification or ECCE with posterior chamber intraocular lens (IOL) implantation by the same surgeon. Applied IOLs were AMO(R) Phacoflex(R) II SI40NB, Acrysof(R) MA60BM, Sensar(TM) AR40e, CeeOn(TM) 811B and CeeOn(TM) 720A. Prediction of post-operative refraction (predictive refraction) was calculated by the SRK/T formula with manufactured A constant. Post-operative manifest refraction (real refraction) was done at least 2 months postoperatively. We compared the difference between the predictive refraction and the real refraction by paired t-test. RESULTS: Total studied eyes were 390 eyes. In all groups, more myopic shift were observed than predicted. In AMO(R) Phacoflex(R) II SI40NB group, statistically significant difference was seen in postoperative manifest refraction over the predictive refraction as much as mean 0.46 diopter myopically (p<0.05, paired t-test), but others were not. In the AR40e implanted group, the error of predictive refraction was the smallest among groups. CONCLUSIONS: Prediction of postoperative refractive state was influenced by various clinical factors. Using a revised A constant, predictive error would be decreased. We recommend that every cataract surgeon had better have one's original A constant over each IOL and A constant may be revised when major surgical or biomedical measurement settings were changed.

Mitomycin C Single Soaking during Surgery for Primary Pterygium

Complications of mitomycin C soaking method during pterygium surgery and its effect on recurrence rate were compared with postoperative use of topical mitomycin C. Sixty three patients(seventy three eyes) with primary pterygium received surgery with the bared sclera method. Thirty nine eyes randomly chosen were treated with cotton applicator soaked with 0.2mg/ml mitomycin C for 5 minutes after the excision of pterygium(soaking group). Thirty four eyes underwent the same surgical procedure and received topical 0.2mg/ml mitomycin C postoperatively, twice a day for five days(eye drop group). During the mean follow-up period of 13 months, recurrence rate was 15.4%(6 eyes) in soaking group and 20.6%(7 eyes) in eye drop group respectively. This difference was not statistically significant(p>0.5). There were no specific complications related to mitomycin C treatment in both groups during the follow-up periods. The soaking method of 0.2mg/ml mitomycin C was found as effective and safe as postoperative use of topical 0.2mg/ml mitomycin C for prevention of the recurrence of primary pterygium.