Abstract
Purpose::
To investigate the impact of preoperative tear function on visual outcome following keratoplasty for keratoconus
Methods::
Twenty-four eyes of 23 patients ( 4 females,19 males; mean age: 34.5 years) with keratoconus who underwent keratoplasty were included in this prospective study.20 patients underwent penetrating keratoplasty and 3 patients underwent deep lamellar keratoplasty.One patient who had a rejection episode throughout the study was excluded. All subjects underwent Landolt visual acuity, subjective and objective refraction tests, corneal topography, Schirmer test, tear film break up time, corneal sensitivity, and fluorescein staining score measurements before as well as 1 month, 3 months, 6 and 12 months after keratoplasty. Patients were divided into two groups as those with Schirmer test value greater than 10 mm and those less than 10 mm. Mann Whitney test was used to study the relation between the tear quantity and the duration until the attainment of best corrected visual acuity. Linear regression analysis was used to study the statistical significance of time wise change of each examined parameter. Informed consents and ethic board reviews were obtained.
Results::
Postoperative best corrected visual acuity improved in all subjects. There were no statistically significant differences between the mean Schirmer test, tear film break up time, fluorescein staining score, surface asymmetry and irregularity indices, and astigmatism at each examination point before and after keratoplasty. However, the duration until the attainment of best corrected visual acuity was significantly shorter in patients with Schirmer test value greater than 10 mm when compared to patients with Schirmer test scores less than 10 mm (p<0.05).
Conclusions::
Preoperative tear quantity appeared to have an influence on the duration of visual recovery in keratoconus patients undergoing keratoplasty.
Keywords: cornea: clinical science • cornea: tears/tear film/dry eye • keratoconus