ABSTRACT
PURPOSE: To compare the clinical outcome of combined small incision lenticule extraction and collagen cross-linking (SMILE Xtra) with SMILE. METHODS: This study included 30 eyes from 15 patients who had undergone SMILE Xtra and a random sample of 30 eyes from 15 patients receiving SMILE alone during the same period. We obtained the following parameters from all patients: uncorrected (UDVA) and corrected distance visual acuity (CDVA), spherical equivalent (SE), efficacy and safety index, and corneal high-order aberrations. RESULTS: The SMILE Xtra group had higher preoperative SE and thinner central corneal and residual stromal bed thickness and optic zone diameter compared to the control group (p < 0.001). At 6 months, there was no significant difference in UDVA or CDVA between the two groups. The efficacy indices were 0.97 ± 0.16 and 1.05 ± 0.17 in the SMILE Xtra and control groups, respectively (p = 0.044), and there was no significant difference in safety index between the two groups during the follow-up period. Total corneal high-order aberrations numbered 2.59 ± 0.56 and 2.02 ± 0.41 in the SMILE Xtra and control groups, respectively (p < 0.001), and there was significant increase in spherical aberration and horizontal corneal aberration in both groups compared to preoperative results. Corneal haze was observed in 20% of eyes in the SMILE Xtra group, and no complication such as corneal ectasia was observed during the follow-up period. CONCLUSIONS: SMILE Xtra had good early clinical outcome compared to SMILE alone. It appears that SMILE Xtra can be a good modality when the cornea is thin or SE is high. However, postoperative corneal haze should be considered.
Subject(s)
Humans , Collagen , Cornea , Dilatation, Pathologic , Follow-Up Studies , Visual AcuityABSTRACT
PURPOSE: To compare the clinical outcome of combined small incision lenticule extraction and collagen cross-linking (SMILE Xtra) with SMILE. METHODS: This study included 30 eyes from 15 patients who had undergone SMILE Xtra and a random sample of 30 eyes from 15 patients receiving SMILE alone during the same period. We obtained the following parameters from all patients: uncorrected (UDVA) and corrected distance visual acuity (CDVA), spherical equivalent (SE), efficacy and safety index, and corneal high-order aberrations. RESULTS: The SMILE Xtra group had higher preoperative SE and thinner central corneal and residual stromal bed thickness and optic zone diameter compared to the control group (p < 0.001). At 6 months, there was no significant difference in UDVA or CDVA between the two groups. The efficacy indices were 0.97 ± 0.16 and 1.05 ± 0.17 in the SMILE Xtra and control groups, respectively (p = 0.044), and there was no significant difference in safety index between the two groups during the follow-up period. Total corneal high-order aberrations numbered 2.59 ± 0.56 and 2.02 ± 0.41 in the SMILE Xtra and control groups, respectively (p < 0.001), and there was significant increase in spherical aberration and horizontal corneal aberration in both groups compared to preoperative results. Corneal haze was observed in 20% of eyes in the SMILE Xtra group, and no complication such as corneal ectasia was observed during the follow-up period. CONCLUSIONS: SMILE Xtra had good early clinical outcome compared to SMILE alone. It appears that SMILE Xtra can be a good modality when the cornea is thin or SE is high. However, postoperative corneal haze should be considered.