Intraocular lens power calculation using total keratometry and ray tracing in eyes with previous small incision lenticule extraction - A case series.

Purpose: To assess the IOL power calculation accuracy in post-SMILE eyes using ray tracing and a range of total keratometry based IOL calculation formulae. Observations: Ray tracing showed excellent predictability in IOL power calculation after SMILE and its accuracy was clinically comparable with the Barrett TK Universal II and Haigis TK formula. Conclusions and importance: Incorporating posterior corneal curvature measurements into IOL power calculation after SMILE seems prudent. The ray tracing method as well as selected TK-based formulae yielded excellent accuracy and should be favored in post-SMILE eyes.

IOL Power Calculations and Cataract Surgery in Eyes with Previous Small Incision Lenticule Extraction.

Small incision lenticule extraction (SMILE), with over 5 million procedures globally performed, will challenge ophthalmologists in the foreseeable future with accurate intraocular lens power calculations in an ageing population. After more than one decade since the introduction of SMILE, only one case report of cataract surgery with IOL implantation after SMILE is present in the peer-reviewed literature. Hence, the scope of the present multicenter study was to compare the IOL power calculation accuracy in post-SMILE eyes between ray tracing and a range of empirically optimized formulae available in the ASCRS post-keratorefractive surgery IOL power online calculator. In our study of 11 post-SMILE eyes undergoing cataract surgery, ray tracing showed the smallest mean absolute error (0.40 D) and yielded the largest percentage of eyes within ±0.50/±1.00 D (82/91%). The next best conventional formula was the Potvin-Hill formula with a mean absolute error of 0.66 D and an ±0.50/±1.00 D accuracy of 45 and 73%, respectively. Analyzing this first cohort of post-SMILE eyes undergoing cataract surgery and IOL implantation, ray tracing showed superior predictability in IOL power calculation over empirically optimized IOL power calculation formulae that were originally intended for use after Excimer-based keratorefractive procedures.

OCT- versus Scheimpflug-based Total Corneal Power Measurements Changes in Myopic Astigmatic SMILE Procedures.

PURPOSE: To evaluate the value of total keratometry (TK) to estimate corneal power in eyes that underwent SMILE for treatment of myopia or myopic astigmatism in subgroups of low and high astigmatism. METHODS: The difference between preoperative and postoperative measurements of corneal power (ΔTCRP, ΔTK) was compared with the surgically induced refractive change at the corneal plane (ΔSEco) by Pearson correlation. Vector analysis of TCRP- and TK-derived astigmatism was performed to evaluate the corneal astigmatism. Single-angle plots were generated with the AstigMATIC tool for standard astigmatism vector analysis. RESULTS: Paired t-test revealed statistically significant differences in preoperative (p = .02) and postoperative (p = .0455) measurements between TK and TCRP in the group of high-level astigmatism and the postoperative low astigmatism group (p < .01). No significant differences were found in preoperative data in the group of low-level astigmatism (p = .60). The correlation of ΔSEco and TK (low astigmatism, R2 = 0.978; high astigmatism R2 = 0.980) was stronger than the correlation of TCRP 4.0 mm and ΔSEco (low astigmatism, R2 = 0.743; high astigmatism R2 = 0.959) in both astigmatic groups. The vector analysis demonstrated nearly identical results concerning the correction index (CI) for TK and TCRP. Comparing the difference vector (DV) between both parameters, TK-derived results were closer to the optimum. CONCLUSIONS: The findings endorse TK as a reliable measure of corneal power after SMILE in patients with low and high astigmatism.

Patient-Reported Quality of Life and Satisfaction After Refractive Lens Extraction Using a Diffractive Trifocal IOL: A Multicenter Retrospective Cohort Study.

PURPOSE: To assess patient satisfaction and quality of life after refractive lens exchange with a trifocal intraocular lens (IOL). METHODS: Consecutive patients who underwent refractive lens exchange with the AT LISA tri or AT LISA tri toric IOL (Carl Zeiss Meditec AG) at one of five surgical centers were surveyed for their quality of life and satisfaction after surgery using a standardized questionnaire. Patient responses were compared to patient characteristics such as age, sex, axial lengths, and preoperative refraction. RESULTS: A total of 102 patients with 204 treated eyes were included in the analysis. The mean age was 54.6 ± 5.2 years. A total of 172 eyes were hypermetropic, 3 were emmetropic, and 25 were myopic, with a mean preoperative refractive error of 0.93 ± 2.17 diopters. Reported postoperative satisfaction was as follows: 81.4% stated that their expectations were completely met and 17.6% stated that they were partially met. Self-reported refractive error quality of life improved significantly in all queried areas of life. Most frequently reported postoperative limitations were driving at night and driving in bad weather conditions. Halos were reported by 91 (90.1%) patients. CONCLUSIONS: Patient satisfaction and self-reported quality of life after refractive lens exchange with the AT LISA tri or AT LISA tri toric IOL was high. Glare and halos remain the only significant drawback of the procedure, leading to 40% of patients experiencing difficulties in night driving. Preoperative communication of these drawbacks is obligatory to avoid postoperative disappointment. [J Refract Surg. 2021;37(11):768-774.].

Surface Ablation Versus CIRCLE for Myopic Enhancement After SMILE: A Matched Comparative Study.

PURPOSE: To compare the outcomes of enhancement after small incision lenticule extraction (SMILE) using surface ablation versus the VisuMax CIRCLE option (Carl Zeiss Meditec AG, Jena, Germany), which converts the SMILE cap into a femtosecond laser-assisted laser in situ keratomileusis flap. METHODS: The databases of the SMILE Eyes centers in Munich, Marburg, and Cologne, Germany, and Linz, Austria, were screened for eyes that had undergone enhancement using surface ablation with mitomycin C or CIRCLE. Eyes from both enhancement methods suitable for a retrospective matched analysis were identified based on pre-SMILE and pre-enhancement mean refractive spherical equivalent (MRSE), astigmatism, age, and corrected and uncorrected distance visual acuity (CDVA/UDVA). Refractive and functional outcomes were compared after a follow-up of 3 months. RESULTS: After the application of the matching criteria on 2,803 SMILE procedures, 24 eyes (12 in each group) with a follow-up of 3 months or longer were available for analysis. Enhancement was performed after a mean 9.7 ± 7.2 (surface ablation) and 11.0 ± 4.4 (CIRCLE) months for a residual MRSE of -0.91 ± 0.55 (surface ablation) and -0.90 ± 0.61 (CIRCLE) diopters. At 3 months, residual MRSE showed comparable accuracy with -0.07 ± 0.19 (surface ablation) and 0.04 ± 0.22 (CIRCLE) diopters (P = .18). UDVA improvement was similar to a final value of 0.02 ± 0.10 (surface ablation) versus 0.03 ± 0.07 (CIRCLE) logMAR (P = .78). Only one eye in the surface ablation group and no eye in the CIRCLE group lost one line of CDVA. At 3 months, the safety (surface ablation: 1.00, CIRCLE: 1.06; P = .36) and efficacy (surface ablation: 0.95, CIRCLE: 1.03; P = .36) indices were equivalent. In terms of speed of visual recovery, at week 1 UDVA and CDVA were significantly better after CIRCLE than surface ablation (P = .008 and .002, respectively). CONCLUSIONS: In this first study directly comparing surface ablation versus CIRCLE enhancement after SMILE, both methods yielded comparable results at 3 months. However, CIRCLE re-treated eyes showed a markedly increased speed of recovery concerning UDVA and CDVA compared to surface ablation. [J Refract Surg. 2019;35(5):294-300.].

Flushing versus not flushing the interface during small-incision lenticule extraction.

PURPOSE: To assess the differences in outcomes between interface flushing with a balanced salt solution after refractive lenticule removal in simultaneous uneventful bilateral small-incision lenticule extraction (SMILE). SETTING: Six study centers in Germany. DESIGN: Prospective case series. METHODS: Patients with myopia or myopic astigmatism of similar magnitude in both eyes with a spherical equivalent less than or equal to 10.0 diopters (D), preoperative corrected distance visual acuity (CDVA) of 0.80 decimal or better, and anisometropia less than or equal to 2.0 D were enrolled and followed for 3 months. One eye of each patient was treated with interface flushing after dry extraction of the lenticule. Flushing was performed with 1.0 cc balanced salt solution using a single-use 27-gauge cannula. The uncorrected distance visual acuity (UDVA) at 1 day, 1 week, and 3 months; the CDVA at 3 months; and postoperative differences at the slitlamp examination were recorded. Statistical analyses were performed with logarithm of the minimum angle of resolution values using paired t tests. The P value for significance was less than 0.05. RESULTS: The study analyzed 470 eyes. One day postoperatively, the mean UDVA was 0.81 in the non-flush group and 0.83 in the flush group (P = .110). At the last visit 3 months postoperatively, the mean UDVA was 1.04 and 1.05, respectively (P = .172). No significant differences in the rate of postoperative complications were found. CONCLUSION: Interface irrigation with 1.0 cc of balanced salt solution after the removal of the refractive lenticule has neither advantages nor disadvantages in terms of visual recovery, postoperative complications, or final visual acuity.

CIRCLE Enhancement After Myopic SMILE.

PURPOSE: To report the outcomes of enhancement after small incision lenticule extraction (SMILE) using the VisuMax CIRCLE option (Carl Zeiss Meditec AG, Jena, Germany), which converts the SMILE cap into a femtosecond LASIK flap for secondary excimer laser application. METHODS: Of 2,065 SMILE procedures, 22 eyes (1.1%) re-treated with CIRCLE with a follow-up of 3 months were included in the analysis. SMILE was performed in the usual manner. For re-treatment, the CIRCLE procedure was performed with pattern D flap creation on the VisuMax system and subsequent excimer laser ablation with a Zeiss MEL 90 laser (Carl Zeiss Meditec) with plano target in all cases. RESULTS: Spherical equivalent was -5.56 ± 2.22 diopters (D) before SMILE and -0.51 ± 1.08 D before CIRCLE. CIRCLE enhancement was performed after a mean of 10.0 ± 7.9 months, allowed for safe flap lifting in all eyes, and resulted in a final manifest refraction spherical equivalent of 0.18 ± 0.31 D at 3 months (P < .008). The number of eyes within 0.50 and 1.00 D from target refraction increased from 31.8% to 90.9% and from 77.3% to 100%, respectively. Mean uncorrected distance visual acuity (UDVA) had already improved from 0.37 ± 0.16 to 0.08 ± 0.16 logMAR at 1 week (P < .0001), resulting in 0.03 ± 0.07 logMAR at 3 months (P < .0001). All eyes gained at least one line of UDVA. Corrected distance visual acuity (CDVA) remained unchanged at all time points (before vs after CIRCLE, P = .40). Two eyes (9.1 %) lost one line of CDVA; no eye lost two or more lines. The safety and efficacy indices were 1.03 and 0.97 at 3 months. CONCLUSIONS: The CIRCLE procedure represents an effective re-treatment option after SMILE. Compared to surface ablation re-treatment after SMILE, CIRCLE seems to offer advantages in respect to speed of visual recovery, safety, and predictability, but at the price of flap creation. [J Refract Surg. 2018;34(5):304-309.].

Enhancement After Myopic Small Incision Lenticule Extraction (SMILE) Using Surface Ablation.

PURPOSE: To report the feasibility and outcomes of surface ablation after small incision lenticule extraction (SMILE). METHODS: In this retrospective evaluation of 1,963 SMILE procedures, 43 eyes (2.2%) were re-treated at three separate clinics. Of these, 40 eyes of 28 patients with a follow-up of at least 3 months were included in the analysis. During surface ablation, mitomycin C was applied for haze prevention. RESULTS: Spherical equivalent was -6.35 ± 1.31 diopters (D) before SMILE and -0.86 ± 0.43 D before surface ablation. Surface ablation was performed after a mean of 9.82 ± 5.27 months and resulted in a spherical equivalent of 0.03 ± 0.57 D at 3 months (P < .0001). The number of patients within ±0.50 and ±1.00 D of target refraction increased from 22.5% to 80% and from 72.5% to 92.5%, respectively. Mean uncorrected distance visual acuity (UDVA) improved from 0.23 ± 0.20 to 0.08 ± 0.15 logMAR (P < .0001); 65% of patients gained at least one line. Corrected distance visual acuity (CDVA) remained unchanged with 0.01 ± 0.07 logMAR before versus -0.01 ± 0.05 logMAR after re-treatment (P = .99). Six eyes (15.0%) lost one line of CDVA, but final CDVA was 0.00 logMAR in four and 0.10 logMAR in two of these cases. The safety and efficacy indices were 1.06 and 0.90 at 3 months, respectively. Three of the four surface ablation profiles (Triple-A, tissue-saving algorithm, and topography-guided) resulted in equally good results, whereas enhancement with the aspherically optimized profile (ASA), used in two eyes, resulted in overcorrection (+1.38 and +1.75 D). CONCLUSIONS: Combined with the intraoperative application of mitomycin C, surface ablation seems to be a safe and effective method of secondary enhancement after SMILE. Due to the usually low residual myopia, the ASA profile is not recommended in these cases. [J Refract Surg. 2017;33(8):513-518.].

Evaluation of Changes in Human Corneas After Femtosecond Laser-Assisted LASIK and Small-Incision Lenticule Extraction (SMILE) Using Non-Contact Tonometry and Ultra-High-Speed Camera (Corvis ST).

PURPOSE: To evaluate theoretical biomechanical advantages of human corneas treated with small incision lenticule extraction (SMILE) compared with femtosecond laser-assisted LASIK (FS-LASIK) Patients and methods: In a prospective, comparative, non-randomized, consecutive case series patients with moderate to high myopia and/or astigmatism underwent corneal refractive surgery. Patients either received standard FS-LASIK or SMILE. Preoperatively and up to 3 months postoperatively data were analyzed including tomography with Pentacam HR, Goldmann tonometry, non-contact tonometry, and deformability of the cornea using an ultra-high-speed camera (Corvis ST). Data were analyzed and p < 0.05 was considered as statistically significant (t-test). RESULTS: Seventy-three patients (128 eyes) were treated. Forty-eight eyes of 29 patients underwent FS-LASIK and 80 eyes of 44 patients underwent SMILE. Preoperative spherical equivalent (SE) was -3.23 ± 1.64 D (FS-LASIK group) and -4.83 ± 1.63 D (SMILE group) (p < 0.0001). Almost all parameters obtained by Corvis ST between preoperative and postoperative measurements showed significant changes after refractive surgery. Significant changes were seen between both groups postoperatively. However, matched pair subgroup analysis (n = 69; 26 eyes FS-LASIK; 43 eyes SMILE) of eyes with initially equal pachymetry, intraocular pressure, SE, and difference of pre- to postoperative pachymetry (p>0.05), showed no significant changes in parameters measured with Corvis ST (p>0.05). CONCLUSIONS: Corneal biomechanical parameters measured preoperatively with Corvis ST showed significant differences postoperatively in total and in both groups. In subgroup analysis with homogenous groups, FS-LASIK showed no significant changes in biomechanical data measured with Corvis ST compared with SMILE.

Imaging of posterior chamber phakic intraocular lens by optical coherence tomography.

We demonstrate the applicability of optical coherence tomography to visualize the distance between the intraocular lens (IOL) and the lens capsule (lens vault) after implantation of the Staar Collamer posterior phakic IOL, also known as the implantable contact lens (ICL). Maintaining a substantial lens vault may be important to avoid cataract formation, but the lens vault was found to change over time; changes in accommodation and pupil size have also been noted. Optical coherence tomography allows precise assessment of the anatomic relationship between the ICL and the crystalline lens in a noncontact, noninvasive manner, permitting dynamic monitoring of changes in accommodation and pupil size.