Lamellar surgeries with SMILE-derived lenticules

PURPOSE

Lamellar surgeries with SMILE lenticules are an evolving field of refractive surgery. This chapter intends to discuss the reported clinical results of using SMILE derived lenticules in terms of feasibility, safety and predictability; or the potential management of hyperopia, keratoconus, SMILE ectasia and presbyopia.

MATERIALS AND METHODS

Donor SMILE lenticules were prepared under microscope tocreate doughnut shaped lenticules. For hyperopia, this tissue was then inserted into afemtosecond laser enabled pocket created using VisuMax FS Laser at a depth of 160µm. For ectasia induced by keratoconus and post refractive procedure (SMILE), 0.23% riboflavin dye was instilled into the interface and then lenticule was inserted followed by exposure to UV-A radiation with total energy of 6.3 J.

RESULTS

Spherical equivalent (S.E.) of within ± 0.5 D was observed in 50% (n=21) eyes and within 1 D was seen in 71% eyes treated for hyperopia. A significant increase in the K mean anterior, central corneal thickness, Q-value and corneal aberrations was seen 2 weeks post-op. Clinical improvement in terms of S.E. and uncorrected distance visual acuity in eyes treated for ectasia after keratoconus and post refractive procedure (SMILE) was seen.

CONCLUSION

With the ample availability of SMILE- derived lenticules, researchers are exploring the possibility of using this tissue for the treatment of various refractive and corneal conditions.

Comparison of Visual Outcomes and Higher-order Aberrations Between FS-LASIK and SMI-LIKE for Moderate to High Hyperopia: A 2-Year Result

PURPOSE

The aim of the study was to evaluate and compare the long-term visual outcomes and higher-order aberrations (HOAs) between femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and small-incision lenticule intrastromal keratoplasty (SMI-LIKE) in the correction of moderate to high hyperopia.

METHODS

In this study, 16 subjects (20 eyes) underwent FS-LASIK and 7 subjects (10 eyes) underwent SMI-LIKE. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, mean keratometry (Km), anterior asphericity (Q), and HOAs preoperatively and 2 years postoperatively were obtained in both procedures.

RESULTS

The efficacy indices of the FS-LASIK group and the SMI-LIKE group were 0.85 ± 0.14 and 0.87 ± 0.17, respectively. The safety indices of the FS-LASIK and SMI-LIKE groups were 0.99 ± 0.15 and 1.08 ± 0.24, respectively. No significant difference in safety index or efficacy index was found between the FS-LASIK and SMI-LIKE groups (all P > 0.05). The correlation coefficient of the attempted versus achieved spherical equivalent postoperatively was 0.69 ( P < 0.01) and 0.89 ( P < 0.01) in the FS-LASIK group and SMI-LIKE groups, respectively. The front Km, negative Q value, negative spherical aberrations (SAs), coma, and total HOAs significantly increased postoperatively in the 2 groups ( P < 0.05). The FS-LASIK group had greater changes in Q value and SA postoperatively than the SMI-LIKE group ( P < 0.01).

CONCLUSIONS

SMI-LIKE had similar safety and efficacy to FS-LASIK in the correction of moderate to high hyperopia. However, SMI-LIKE may equip better visual quality postoperatively for its lower Q value and SA changes than FS-LASIK.

Femtosecond Intrastromal Lenticule Implantation (FILI) for Management of Moderate to High Hyperopia: 5-Year Outcomes

PURPOSE

To report the long-term clinical experience following femtosecond intrastromal lenticule implantation (FILI) for the management of moderate to high hyperopia.

METHODS

Eligible patients who underwent FILI for moderate to high hyperopia from July 2013 to October 2020 were included. A donor small incision lenticule extraction lenticule, matched for refractive error, was implanted into the recipient's corneal pocket created using a femtosecond laser at 160 µm depth. Visual and refractive outcomes and long-term complications were evaluated at the end of a mean follow-up of 68 ± 17.28 months (5.6 years).

RESULTS

Forty-two eyes of 25 patients (mean age: 27.29 ± 5.52 years) were analyzed. The mean spherical equivalent reduced significantly from +5.50 ± 1.96 to +0.66 ± 1.17 diopters (D) at last follow-up visit. Thirty eyes (71%) were within ±1.00 D of spherical equivalent correction. Cumulative uncorrected distance visual acuity of 20/40 or better was achieved in 34 eyes (81%). Efficacy and safety indices were 0.86 ± 0.19 and 1.17 ± 0.39, respectively. There was a significant increase in mean keratometry (Kmean) anterior, central corneal thickness, Q-value, and corneal higher order aberrations and a decrease in Kmean posterior 2 weeks postoperatively, without any significant change in these parameters thereafter (P > .05). Four eyes of 3 patients underwent enhancement and another 4 eyes underwent explantation of the lenticule followed by exchange (2 eyes) and hyperopic laser in situ keratomileusis (2 eyes). No eye lost more than one line of CDVA.

CONCLUSIONS

At 5 years of follow-up, FILI for moderate to high hyperopia showed good safety, efficacy, and reversibility. Modification of nomograms and surgical planning may be employed for further refinement of the outcomes. [J Refract Surg. 2022;38(6):348-354.].