Wydanie 2/2006

Korekcja astygmatyzmu powstałego po przeszczepie drążącym rogówki

Astmigmatism Correction after Penetrating Keratoplasty

Iwona Liberek1,3, Jerzy Szaflik2,3

1 Klinika Okulistyki Centrum Medycznego Kształcenia Podyplomowego w Warszawie
Po. kierownika: dr n. med. Iwona Liberek
2 Katedra i Klinika Okulistyki II Wydziału Lekarskiego Akademii Medycznej w Warszawie
Kierownik: prof. dr hab. n. med. Jerzy Szaflik
3 Centrum Mikrochirurgii Oka LASER w Warszawie
Kierownik: prof. dr hab. n. med. Jerzy Szaflik

Summary: Qualified for laser astigmatism correction after corneal transplantation are patients in whom we are unable to obtain useful visual acuity by means of spectacles or contact lenses as well as anisometropic patients.
During a pre-op screening examination for a laser vision correction surgery we must consider the following: cornea diseases with special focus on history of viral inflammations, systemic diseases that may influence the final outcome of healing e.g. collagenosis. We must test the spectacle and hard lens corrected visual acuity, evaluate stability of refraction and topography map (stable topography in two months preceeding the surgery (Orbscan). This is why the period after removing the sutures should be at least 4 months to, preferably, 12 months.
We verify whether there is no neovascularization in the incision and ablation area. Although, according to literature, laser correction procedures do not influence the number of endothelial cells, we should consider performing the procedure in patients with a very low number of cells with decompensation risk.
Particularly with LASIK, one should evaluate the corneal thickness in minimum 8 to 16 points in order to avoid cornea perforation during flap creation. While creating the flap, we adjust the incision depth to 160-180 µ and keep the flap over the graft.
Materials and methods: To date, Warsaw-based Eye Microsurgery Centre LASER has performed laser astigmatism correction after corneal transplantation in 24 eyes. Average patient age was 36.7 (between 27 and 72 years). The procedures have been performed in the TOSCA system with Zeiss-Meditec MEL 70 laser in 8-12 months after removal of sutures. Operated myopic eyes ranged from -2.5 D to -6.0 D, while myopic astigmatism ranged from 4.75 Dcyl to 10.0 Dcyl (average ES of -5.5 D)
Results: Improvement was observed after two years in 30% of the eyes compared to pre-op best corrected visual acuity. Post-op corrected visual acuity of 0.5 or higher was achieved in 72.3% of eyes, while a similar pre-op visual acuity had been scored only in 41.1% of eyes.
Conclusions: The TOSCA system allows for obtaining satisfactory refraction in most cases of irregular astigmatism developed after previous ophthalmic procedures. In most cases, the system allows for a complete reduction of glare and dispersion of light and has a positive effect on improvement in vision quality.

Keywords: penetrating keratoplasty, topography customised ablation