Effective optical zone after corneal lenticule extraction with the CLEAR femtosecond laser application

Submitted: 10 September 2023
Accepted: 15 November 2023
Published: 23 November 2023
Abstract Views: 4137
PDF: 100
Publisher's note
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

Authors

Laser vision correction of myopia induces an effective optical zone (EOZ) smaller than the programmed optical zone (POZ) by 16 to 26%. We evaluated the EOZ after corneal lenticule extraction for myopia with astigmatism ≤1 diopter (D) with a new femtosecond laser application (CLEAR), compared to POZ in a retrospective, consecutive, comparative case series study. Forty eyes of 40 patients underwent lenticule extraction with the Ziemer CLEAR® application; the control group was composed of 40 eyes of 40 patients receiving myopic femtosecond laser in situ keratomileusis (LASIK); EOZ was calculated on difference tangential maps at 6 months. For lenticule extraction, mean preoperative spherical equivalent (SE) was -6.03±2.48 D; mean POZ was 6.43±0.27 mm; EOZ 5.55±0.45 mm; mean difference between POZ and EOZ was 0.88 ± 0.28 mm (p=0.00); the mean reduction of EOZ compared to POZ was 13.60%±4.75; a positive correlation between preoperative SE and percent reduction of EOZ was found (r=0.63). For LASIK, mean preoperative SE was -5.89±2.14 D; mean POZ was 6.57±0.34 mm; EOZ 5.16±0.53 mm; the mean difference between POZ and EOZ was 1.41±0.35 mm (p=0.00); the mean reduction of EOZ compared to POZ was 21.46%±5.20. The mean difference between EOZ of the 2 procedures was 0.39 mm (p=0.0008). The mean difference between the reduction in optical zone (POZ-EOZ) of the 2 procedures was -0.53 (p=0.00). In conclusion, in myopia with low astigmatism, the CLEAR application for lenticule extraction provided a limited reduction in EOZ, compared with existing platforms. A positive correlation exists between corrected SE and reduction of the EOZ.

Dimensions

Altmetric

PlumX Metrics

Downloads

Download data is not yet available.

Citations

Tabernero J, Klyce SD, Sarver EJ, Artal P. Functional optical zone of the cornea. Invest Ophthalmol Vis Sci 2007;48:1053-60. DOI: https://doi.org/10.1167/iovs.06-0867
Freedman KA, Brown SM, Mathews SM, Young RSL. Pupil size and the ablation zone in laser refractive surgery: considerations based on geometric optics. J Cataract Refract Surg 2003;29:1924-31. DOI: https://doi.org/10.1016/S0886-3350(03)00214-1
Sekundo W, Kunert KS, Blum M. Small incision corneal refractive surgery using the small incision lenticule extraction (SMILE) procedure for the correction of myopia and myopic astigmatism: results of a 6 month prospective study. Br J Ophthalmol 2011;95:335–9 DOI: https://doi.org/10.1136/bjo.2009.174284
Hou J, Wang Y, Lei Y, Zheng X. Comparison of effective optical zone after small-incision lenticule extraction and femtosecond laser-assisted laser in situ keratomileusis for myopia. J Cataract Refract Surg 2018;44:1179-85. DOI: https://doi.org/10.1016/j.jcrs.2018.06.046
Damgaard IB, Ang M, Mahmoud AM, et al. Functional optical zone and centration following SMILE and LASIK: a prospective, randomized, contralateral eye study. J Refract Surg 2019;35:230-7. DOI: https://doi.org/10.3928/1081597X-20190313-01
Sun L, Lin H-N, Jhanji V, et al. Changes in effective optical zone after small-incision lenticule extraction in high myopia. Int Ophthalmol 2022;42:3703-11. DOI: https://doi.org/10.1007/s10792-022-02367-6
Liu S, Zhang X, Niu L, et al. Comparison of the functional optical zone in eyes with high myopia with high astigmatism after SMILE and FS-LASIK. J Refract Surg 2022;38:595-601. DOI: https://doi.org/10.3928/1081597X-20220725-01
Song YW, Cui MF, Feng Y, et al. Comparative study of functional optical zone: small incision lenticule extraction versus femtosecond laser assisted excimer laser keratomileusis. Int J Ophthalmol 2023;16:238-44. DOI: https://doi.org/10.18240/ijo.2023.02.10
Leccisotti A, Fields SV, De Bartolo G. Refractive corneal lenticule extraction with the CLEAR femtosecond laser application. Cornea 2023;42:1247-56. DOI: https://doi.org/10.1097/ICO.0000000000003123
Ding X, Fu D, Wang L, et al. Functional optical zone and visual quality after small-incision lenticule extraction for high myopic astigmatism. Ophthalmol Ther 2021;10:273-88. DOI: https://doi.org/10.1007/s40123-021-00330-9
Chang DH, Waring GO IV. The subject-fixated coaxially sighted corneal light reflex: a clinical marker for centration of refractive treatments and devices. Am J Ophthalmol 2014;158:863-74. DOI: https://doi.org/10.1016/j.ajo.2014.06.028
Reinstein DZ, Archer TJ, Randleman JB. Mathematical model to compare the relative tensile strength of the cornea after PRK, LASIK, and small incision lenticule extraction. J Refract Surg 2013;29:454-60. DOI: https://doi.org/10.3928/1081597X-20130617-03
Reinstein DZ, Gobbe M, Archer TJ. Coaxially sighted corneal light reflex versus entrance pupil center centration of moderate to high hyperopic corneal ablations in eyes with small and large angle kappa. J Refract Surg 2013;29:518-25. DOI: https://doi.org/10.3928/1081597X-20130719-08
Miot HA. Correlation analysis in clinical and experimental studies. J Vasc Bras 2018;17:275-9. DOI: https://doi.org/10.1590/1677-5449.174118
Huang Y, Ding X, Han T, et al. Effective optical zone following small incision lenticule extraction for myopia calculated with two novel methods. J Refract Surg 2022;38:414-21. DOI: https://doi.org/10.3928/1081597X-20220608-02
He S, Luo Y, Chen P, et al. Prospective, randomized, contralateral eye comparison of functional optical zone, and visual quality after SMILE and FS-LASIK for high myopia. Transl Vis Sci Technol 2022;11:13. DOI: https://doi.org/10.1167/tvst.11.2.13
Wei PH, Wang Y, Li H, et al. Effect of optical zone diameter on corneal biomechanical properties after small incision lenticule extraction. [Zhonghua yan ke za hi] Chinese J Ophthalmol 2017;53:182-7.
Roy AS, Dupps WJ Jr, Roberts CJ. Comparison of biomechanical effects of small-incision lenticule extraction and laser in situ keratomileusis: finite-element analysis. J Cataract Refract Surg 2014;40:971-80. DOI: https://doi.org/10.1016/j.jcrs.2013.08.065
Dupps WJ Jr, Roberts C. Effect of acute biomechanical changes on corneal curvature after photokeratectomy. J Refract Surg 2001;17:658-69. DOI: https://doi.org/10.3928/1081-597X-20011101-05
Ying J, Cai J, Zhu L, Zha Y. Comprehensive evaluation of anterior corneal change in asphericity calculated by the tangential radius of curvature after LASIK. J Ophthalmol 2017:3874371. DOI: https://doi.org/10.1155/2017/3874371
Koller T, Iseli HP, Hafezi F, et al. Q-factor customized ablation profile for the correction of myopic astigmatism. J Cataract Refract Surg 2006;32:584-9. DOI: https://doi.org/10.1016/j.jcrs.2006.01.049
Hashemi H, Roberts CJ, Elsheikh A, et al. Corneal biomechanics after SMILE, femtosecond-assisted LASIK, and photorefractive keratectomy: A matched comparison study. Transl Vis Sci Technol 2023;12:12. DOI: https://doi.org/10.1167/tvst.12.3.12
Li H, Peng Y, Chen M, et al. Six modes of corneal topography for evaluation of ablation zones after small-incision lenticule extraction and femtosecond laser-assisted in situ keratomileusis. Graefes Arch Clin Exp Ophthalmol 2020;258:1555-63. DOI: https://doi.org/10.1007/s00417-020-04674-z
Antonio Leccisotti, Siena Eye Laser, Poggibonsi, Siena; Scuola di Specializzazione in Oftalmologia, Università di Siena

School of Biomedical Sciences, Ulster University, Coleraine, UK

How to Cite

Leccisotti, A., Fields, S. V., De Bartolo, G., & Crudale, C. (2023). Effective optical zone after corneal lenticule extraction with the CLEAR femtosecond laser application. Laser Therapy, 30(2). https://doi.org/10.4081/ltj.2023.326