Evaluation of ocular aberrations with wavefront analyzer in keratoconus patients

Keratoconus is a chronic noninflammatory disorder which usually presents with central or inferior paracentral corneal thinning and protrusion. These structural changes result in high myopia and astigmatism causing decreased visual quality.Keratoconus usually affects young people at their active and productive years influencing their quality of life and efficiency. Currently corneal topography is the gold standart for the diagnosis of keratoconus and detection of risky corneas. In our study keratoconus was diagnosed by demostrating central or paracentral steep areas topographically, corneal thinning in these areas and keratometric values >47,2 D.The wavefront analyzer is a recent technology measuring total or corneal aberrations of the eye which hinder optimal vision. High-order aberrations, especially coma-like aberrations have been more frequently observed in keratoconus patients than in normal eyes.The aim of this study was to evaluate aberrations of keratoconus patients with the wavefront analyzer and compare the effect of different visual rehabilitation methods (glasses, contact lenses, keratoplasty) with normal healthy eyes.Group 1 consisted of 16 randomly chosen eyes of 8 male and 8 female keratoconus patients wearing glasses with a mean age of 33,31 (±9,4). Group 2 consisted of 16 randomly chosen eyes of 9 male and 7 female keratoconus patients with a mean age of 27,25 (±7,5). These patients of group 2 were rigid gas permeable contact lens users. Nine male and 7 female patients who had undergone penetrating keratoplasty comprised group 3. Group 3 patients had a mean age of 32,88 (±9,08). Finally group 4 consisted of 16 randomly chosen eyes of 10 male and 6 female healthy volunteers without any systemic and corneal diseases, with a mean age of 33,31 (±9,4).Patients with diabetes, with a history of ocular trauma, corticosteroids use, ocular surgery and with any corneal pathologies except keratoconus were not included in the study.Keratoconus group (group 1) and the control group were compared in terms of Zernike coefficients. The difference between HOA RMS and total RMS values of Group 1 and the control group were extremely significant; the difference in vertical coma values were also significant (p<0,005). The difference in HOA RMS and total RMS values of patients who underwent keratoplasty and the control group were extremely significant. In terms of coma-like aberrations and spheric aberrations there was no significant difference. No significant difference was noted when rigid gas permeable contact lens users and the control group were compared in terms of vertical coma and total RMS values.In our study the difference in total HOA and especially coma like aberrations in keratoconus patients were remarkably high which supports many similar publications in literature. There are only few publications evaluating rigid gas permeable contact lens users and patients who underwent keratoplasty. The improvement in spheric and coma like aberrations in these groups was also remarkable. Therefore we believe that these results, in rigid gas permeable contact lens users and patients who underwent keratoplasty, will guide other similar publications on this topic.