Abstract
Purpose :
Dry eye may impact clinical parameters therefore diagnosis and treatment prior to cataract surgery is essential to optimizing postoperative refractive outcomes. Using the difference in corneal astigmatic axis between routinely available instruments as an indicator of sub-clinical dry eye requiring preoperative tear film optimisation, we retrospectively analysed changes in keratometry and refractive outcomes in a successive cohort of patients undergoing cataract surgery to determine if this may have clinical utilization.
Methods :
Standard biometrical values were assessed at the initial consultation. A difference of >15° between steep keratometry axis values on the IOLMaster and Pentacam topography required pretreatment prior to surgery. Repeat biometry was indicated following dry eye optimisation. The first eye of 23 consecutive patients were assessed. T-tests analysed changes following pretreatment for both keratometry and refractive parameters.
Results :
Mean age of cohort was 73.2 ± 6.9 years. Preoperative spherical equivalent was 0.86 ± 2.16D with refractive cylinder 0.60 ± 0.56D. The mean difference in keratometry axis between eyes was 33.8 ± 20.5° (range 9.4° to 88.1°). 19 eyes underwent dry eye treatment. Following treatment, the mean difference reduced from 38.1 ± 19.4° to 23.2 ± 25.5° (p = 0.06). The difference in eyes not requiring pre-treatment (n = 4) was from 13.2 ± 2.6° to 10.5 ± 11.4° (p = 0.65). There was no statistically significant change in mean Pentacam keratometry or keratometric cylinder for either cohort between readings. Mean IOLMaster cylinder in the pre-treated cohort was reduced from 0.63 ± 0.35D to 0.47 ± 0.41D (p = 0.007). The absolute difference from refractive target was 0.24 ± 0.24D and 0.46 ± 0.23D in the treatment and non-treatment cohorts respectively (p = 0.061).
Conclusions :
Our findings support using the discrepancy in keratometry axis to identify sub-clinical dry eye requiring tear film optimisation prior to cataract surgery. There was a statistically significant reduction in the mean IOLMaster keratometric cylinder. This change is likely to have impacted the astigmatic power of the chosen IOL in a number of patients. Final refractive outcomes suggest that pre-treatment was beneficial, particularly in patients with sub-clinical dry eye although a larger sample is required.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.