Delhi: A new study published in the Journal of Refractive Surgery suggests that dry eye has a substantial influence on toric intraocular lens (IOL) estimates and should be considered during preoperative examinations. The use of artificial tears reduced the number of refractive errors.
Elsa Rochet and the team conducted this study in order to see how artificial tears affected the preoperative workup before age-related cataract surgery when a toric IOL was suggested.
This was monocentric prospective research that comprised 73 eyes from 51 patients who had a preoperative work-up without artificial tears (no artificial tears group) when a toric IOL was required. Each patient was subjected to a second set of tests, including biometry with the IOLMaster 700 (Carl Zeiss Meditec AG) and topography with the OPD-Scan II (Nidek), 1 minute after artificial tears were instilled (artificial tears group; hyaluronate de sodium 0.15 percent, threalose 3 percent [Théalose; Théa]). Variations in anterior corneal astigmatism were studied, as were the changes in toric IOL calculation. The expected residual astigmatism error was determined.
The key findings of this study were as follows:
1. When artificial tears were injected before the exams, anterior corneal astigmatism and total corneal astigmatism were dramatically reduced.
2. This alteration resulted in a change in IOL cylinder calculation in 43.8% of instances and a shift in the implantation axis of more than 10 degrees in 17.7% of cases.
3. These alterations were substantially more pronounced in individuals with breakdown times (BUT) smaller than 5 seconds.
4. The mean absolute error in projected astigmatism was considerably reduced following artificial tears installation in the subgroup of patients with a BUT of less than 5 seconds.
In conclusion, when the dry eye is present, the values of corneal astigmatism fluctuate dramatically. This change has a considerable influence on toric IOL computation, whether it's on the IOL cylinder or on the implantation axis. Artificial tears reduce refractive errors, particularly when the BUT becomes less than 5 seconds. As a result, it is critical to include dry eyes during preoperative examinations for refractive cataract surgery.
Reference:
Rochet, E., Levron, A., Agard, E., Chehab, H. E., Plas, H., Bouvarel, H., Chirpaz, N., Billant, J., & Dot, C. (2021). Should Artificial Tears Be Used During the Preoperative Assessment of Toric IOLs Before Age-Related Cataract Surgery? The TORIDE Study. In Journal of Refractive Surgery (Vol. 37, Issue 11, pp. 759–766). SLACK, Inc. https://doi.org/10.3928/1081597x-20210826-01