Spherical equivalent pre- and post-implantable collamer lens implantation in patients with myopia, hyperopia, and...

Refractive errors are common in Saudi Arabia and keratorefractive surgeries are usually done to correct them. However, not all patients are fit and complications postoperatively are a concern. Implantable collamer lens (ICL) implantation can be used for patients who are not fit for keratorefractive surgeries. ICL can also be used for keratoconus. We elected to evaluate the outcomes of patients who had ICL implantation for refractive errors or keratoconus.

We retrospectively reviewed patients aged between 21 and 45 years old, who attended the anterior segment clinic at King Khaled Eye Specialist Hospital and who had spherical equivalent (SE) ranging between (+16 to -23 diopters), and had ICL implantation between February 2015 and September 2017. The SE was documented before and after the surgery. Depending on the SE, patients were divided into two groups (myopia and hyperopia). Statistical analysis was done to evaluate the change in mean SE before and after surgery for patients.

We identified 169 eyes and 155 (92%) were myopic before the surgery. Before surgery, the mean SE was -8.6 and the standard deviation (SD) was 4.4. Only 14 eyes (8%) were hyperopic before the surgery with a mean SE of +5.5 and SD of 4.8. The difference in the mean of SE between after and before the surgery for myopic eyes was statistically significant (mean difference: 7.8, SD: 5, P < 0.0001). The difference in the mean of SE between post- and pre-operatively was also significant for hyperopic eyes (mean difference: -6.1, SD: 5.2, P = 0.0007). In 32 eyes with keratoconus, the mean SE before surgery was -7.9 with an SD of 4.1. For the keratoconus eyes, the mean difference of SE between after and before surgery was statistically significant as the mean difference in SE was 7.2 with an SD of 4.6 (P < 0.0001).

The effect of ICL implantation was significant in improving the SE for myopic, hyperopic, and keratoconus eyes.