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