2M.D. Asistant Professor, Sifa University Faculty of Medicine, Department of Ophthalmology, Izmir/TURKEY Purpose: To examine the contribution of corneal and lenticular components to total ocular astigmatism in patients who were diagnosed cataract and to emphasize the importance of these components in surgical planning for correcting astigmatism.
Materials and Methods: Patients who were examined in Ophthamology service between November 2014 and August 2015 and those who had cataract and required cataract surgery were included in the study. Each study patient underwent a comprehensive ophthalmic examination, which included measurement of best-corrected visual acuity testing, slit-lamp microscopy, intraocular pressure measurement, fundus examination, autorefractometry and keratometry measurements. Refractive parameter's (corneal astigmatism and total ocular astigmatism) measurements were performed with autorefractoceratometry (Canon RK-F2, Canon USA Inc., Lake Success, NY, USA) (horizontal and vertical power and axis). Internal astigmatism was calculated by the subtraction of corneal refraction from the total ocular refraction.
Results: The study comprised 57 eyes of 57 patients who were diagnosed as senile cataract. Mean age was 67.2±5.9 years ( range, 46-86). Twenty-eight patients (49.1%) were male, and the remaining 29 (50.9%) were female. Mean corneal astigmatism was 0.97±0.48 D (range, 0.25-3 D) and mean internal astigmatism was 0.72±0.29 D (range, 0.25-1.50 D). Corneal astigmatism was less than 0.75 D in 43.9% of patients and greater than 0.75 D in 56.1% of patients.
Conclusions: There was a high percentage of corneal astigmatism greater than 0.75 D in patents who were candidates for cataract surgery. Cataract surgeons should be aware of corneal and internal astigmatisms before cataract surgery. Otherwise, there may be unexpected surprises about astigmatism postoperatively.
Keywords : Astigmatic correction, corneal astigmatism, internal astigmatism