97th DOG Annual Meeting 1999
REFRACTIVE AND KERATOMETRIC OUTCOME AFTER TRIPLE PROCEDURE IN FUCHS´ DYSTROPHY - COMPARISION BETWEEN MECHANICAL AND NONMECHANICAL CORNEAL TREPHINATION
A. Walter, B. Seitz, A. Langenbucher, M.M. Kus, G.O.H. Naumann
Purpose: To assess the impact of the trephination method on intraocular lens (IOL) power accuracy, refractive and keratometric outcome after triple procedure for Fuchs´dystrophy in a homogenous patient population.
Patients and Methods: As a part of a prospective, randomized, cross-sectional, clinical study triple-procedure was performed in 59 eyes with Fuchs´dystrophy with donor/recipient diameter of 7.6/7.5mm (from the epithelial side) and a double running diagonal suture by one surgeon (G.O.H.N.). In 26 eyes (age 69.8±6.7 years) a nonmechanical trephination with the 193 nm excimer laser (EXCIMER) and in 33 eyes (age 74.7±6.6) a mechanical motor trephination (CONTROL) was performed. For the IOL power calculation the Haigis formula was used.
Results: The theoretical refraction target of the IOL selected (+23.5±4.9 diopters (D), +10.0 to +35.0 D) did not differ between EXCIMER (-2.3±1.2 D) and CONTROL (-2.5±1.3 D). The average central corneal power of EXCIMER changed minimally from 42.9±2.1 to 42.4±2.6 D but it flattened by 1.5 D from 43.7±1.4 to 42.2±3.9 D in the CONTROL group. After suture removal 83%/55% of patients had a final refraction within 2 D of the expected target refraction. In EXCIMER/CONTROL, preoperative visual acuity was 0.15/0.15 with a spherical equivalent (SEQ) of -1.3±3.1/-1.4±3.4 D and a keratometric astigmatism (KA) of -1.0±0.8/-0.8±0.7 D. After suture removal (21.6±4.3 months) the average visual acuity was 0.48/0.40 with a SEQ of
-1.8±2.9/-0.9±3.4 D and a KA of -4.2±3.4/-5.9±2.9 D. After a mean follow-up time of 30.6±13.2/32.0±12.6 months 67%/50% of the eyes had a best corrected visual acuity of 0.5 or better.
Conclusion: Concerning the accuracy of IOL power calculation and refractive outcome after triple procedure nonmechanical trephination is superior in comparision with conventional mechanical methods. Probably, the exact adaptation of congruent corneal cut surfaces trephined from the epithelial side with negligible donor/recipient graft size disparity may almost preserve the preoperative central corneal curvature thus improve the accuracy of IOL power prediction after the triple procedure.
Department of Ophthalmology and Eye Hospital, University Erlangen-Nürnberg, Schwabachanlage 6, D-91054 Erlangen, Germany