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Intrastromal lenticule rotation for treatment of high astigmatism: the importance of thorough lenticule unfold

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First Author: P.Stodulka CZECH REPUBLIC

Co Author(s):    M. Slovak                    

Abstract Details

Purpose:

The recently introduced concept of intrastromal lenticule rotation showed potential in correcting high astigmatism. However, the technique induced an undesirable myopic shift of -2.75 D of spherical equivalent in the first clinical case and as well as in ex vivo human cornea study. One of the hypotheses is that the myopic shift is because of the lenticule shrinkage after the laser cut. After the rotation, this increases the cornea steeping. Therefore in this case series, the surgeon attempted to very carefully unfold the lenticule to provide a thorough spread to the edges of the pocket.

Setting:

Gemini Eye Clinic, Zlin, Czech Republic

Methods:

Three amblyopic eyes were included for the surgery using SMILE 500 kHz VisuMax femtosecond laser system. The cylindrical power was set to slightly over half of the subjective astigmatism value. The whole lenticule rotation was performed inside without external lenticule manipulation and extra attention was paid to the thorough unfold of the rotated lenticule into the periphery of the pocket. The patients were followed for one week, one and three months after the surgery. Corrected and uncorrected distance visual (UDVA, CDVA) uncorrected near visual acuities (UNVA), refraction, keratometry as well as Pentacam images were recorded.

Results:

Subjective astigmatism of cases 1, 2, and 3 changed from preoperative absolute cylinder 5.0D, 5.5D, and 6.0D to 0.0D, 0.0D, and 0.75D at one-month follow-up while spherical equivalent changed by -0.75D, 0.0D, and -1.125D respectively. UDVA changed from 0.5, 0.6 and 0.8 logMAR preoperatively to 0.54, 0.88 and 0.17 at one month follow-up. CDVA changed from 0.1, 0.1 and 0.0 logMAR preoperatively and 0.3, 0.36 and 0.14 logMAR at one month. UNVA improved so all cases read Jaeger 1 at one month. K mean increased by 1.2D, 0.9D, and 1.7D.

Conclusions:

The importance of thorough lenticule rotation seems to play a crucial role in the post-operative refractive outcomes. As demonstrated in this case series the previous myopic shift of -2.75 D could be potentially reduced by a very careful unfold of the lenticule after the rotation. At this stage would be appropriate to properly evaluate the efficacy of this technique in a cohort of patients.

Financial Disclosure: