Abstract
Purpose: :
To characterize the prevalence of the axis distribution of topographic corneal astigmatism in a cataract surgical population.
Methods: :
A retrospective review of the pre-operative corneal topographies of 2037 consecutive eyes with cataract surgery scheduled with one surgeon over the course of > 1 yr was performed. Patients with pre-existing corneal diagnoses or prior corneal / intraocular surgery were excluded. Multiple topographic systems were utilized; 1627 eyes with studies performed utilizing the same placido-based topography system were identified. Statistical analysis was performed on the topographic, clinical and demographic data of this subset of patients.
Results: :
50.8% of patients with >/= 0.75D of astigmatism had against-the-rule (ATR) and 34.1% had with the-rule (WTR) corneal astigmatism. The prevalence of ATR increased, and the prevalence of WTR decreased significantly (p<0.0001), from 24.0% to 67.1%, and from 56.0% to 13.7% in 50 to 80-year olds, respectively. The prevalence of Oblique astigmatism was 15.1% and varied only slightly between age groups. There was no statistically significant difference in either the prevalence or distribution of astigmatism between the different demographic subgroups analyzed.
Conclusions: :
The prevalence of ATR astigmatism increases significantly with age while the prevalence of WTR astigmatism decreases significantly with age in this surgical population. Further studies are necessary to explore whether such changes occur longitudinally within populations or individuals. If so, these findings may have significant implications for surgical planning, refractive surgery, disorders involving corneal ectasia, as well as the surgical correction of astigmatism performed at the time of cataract surgery.
Keywords: astigmatism • refractive surgery: corneal topography • cornea: clinical science