Issue: Vojnosanit Pregl 2016; Vol. 73 (No. 6)

The assessment of the stability of the corneal structure after LASIK correction of myopia by different optical zone diameters

Authors:
Milorad Milivojević*, Vladimir Petrović*, Miroslav Vukosavljević*†, Ivan Marjanovi懧, Mirko Resan*

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Background/Aim. Enlargement of optical zone (OZ) diameter
during laser in situ keratomileusis (LASIK) correction of
myopia postoperatively improves the optical outcome, however,
it also leads to the increased stroma tissue consumption –
progressive corneal thinning. The aim of this investigation was
to present the possibility of safe OZ enlargement without impairing
the structural stability of the cornea, while obtaining an
improved optical outcome with LASIK treatment of shortsightedness.
Methods. Preoperative assessment of the cornea
structure and prediction of the ablated stroma tissue consumption
was conducted in 37 patients (74 eyes) treated for shortsightedness
by means of the LASIK method. With the eyes
that, according to their cornea structure, had the capacity for
OZ diameter enlargement of 0.5 mm, LASIK treatment was
performed within the wider OZ diameter of 7.0 mm compared
to the standard 6.5 mm. The following two groups were
formed, depending on the diameter of the utilized OZ: the
group I (the eyes treated with the OZ 6.5 mm, n = 37) and the
group II (the eyes treated with the OZ 7.0 mm, n = 37).
Results. No significant difference in the observed structural
parameters of the cornea was detected between the groups of
patients treated with different OZ diameters. The values of all
the parameters were significantly bellow the threshold values
for the development of postoperative ectasia. Conclusion. Diameter
enlargement of the treated OZ, if there is a preoperative
cornea capacity for such enlargement, will not impair the postoperative
stability of the cornea structure, and will significantly
improve the optical outcome.