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Effect of Corneal Transition Zone on Visual Field of Patients with Laser in Situ Keratomileusis: Preliminary Results

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First Author: S.Ozates TURKEY

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Abstract Details

Purpose:

To investigate the effect of the transition zone on the visual field of patients with laser in situ keratomileusis (LASIK).

Setting:

This study was conducted at Istanbul Okan University Medical Faculty, Istanbul, Turkey.

Methods:

This cross-sectional study included 76 subjects. Of the 76, 34 subjects with LASIK surgery formed the LASIK group and 30 healthy subjects formed the control group. Ophthalmological examination including short-wavelength automated perimetry (SWAP) and corneal topography was performed. Main outcomes were visual field sensitivity at each measurement point of the visual field, mean deviation (MD), pattern standard deviation (PSD), and corneal topography parameters including high order aberrations (HOA), coma, astigmatism, and spherical aberration (SA). Secondary outcomes were mean retinal nerve fiber layer (RNFL) thickness in all optic disc quadrants.

Results:

Mean age, gender, and RNFL outcomes did not significantly differ between the groups (p>0.05). The MD was significantly lower in the LASIK group. (p<0.001). The PSD was significantly higher in the LASIK group (p<0.001). The mean topographic outcomes within 5 mm pupil size did not differ between the groups (p>0.05). The mean HOA and SA within 7mm pupil size were significantly higher in the LASIK group (p<0.001 for all). No correlation was found between astigmatism, coma, and HOA and MD and PSD (p>0.05). A mild and negative correlation was found between SA and MD (r = -202, p<0.001).

Conclusions:

The peripheral arcuate scotoma observed in SWAP tests of the LASIK patients corresponded to the transition zone of the ablation. Increased SA and non-uniform myopic ablation in that area might be the reason for this visual field alteration. Further studies are required to reveal if blue-sensitive cones are more sensitive to spherical aberration than other cones.

Financial Disclosure:

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