Update and clinical utility of the LenSx femtosecond laser in cataract surgery

� 2016 Roberts et al. The introduction of femtosecond lasers to cataract surgery has been the major disruptive technology introduced into ophthalmic surgery in the last decade. Femtosecond laser cataract surgery (FLACS) integrates high-resolution anterior segment imaging with a femtosecond laser allowing key steps of cataract surgery to be performed with computer-guided laser accuracy, precision, and reproducibility. Since the introduction of FLACS, there have been significant advances in laser software and hardware as well as surgeon experience, with over 250 articles published in the peer-reviewed literature. This review examines the published evidence relating to the LenSx platform and discusses surgical techniques, indications, safety, and clinical results

Intraocular lens power calculation following laser refractive surgery

Refractive outcomes following cataract surgery in patients that have previously undergone laser refractive surgery have traditionally been underwhelming. This is related to several key issues including the preoperative assessment (keratometry) and intraocular lens power calculations. Peer-reviewed literature is overwhelmed by the influx of methodology to manipulate the corneal or intraocular lens (IOL) powers following refractive surgery. This would suggest that the optimal derivative formula has yet been introduced. This review discusses the problems facing surgeons approaching IOL calculations in these post-refractive laser patients, the existing formulae and programs to address these concerns. Prior published outcomes will be reviewed

Re-treatment in LASIK: To Flap Lift or Perform Surface Ablation.

PURPOSE:To review safety and efficacy outcomes following re-treatment for residual refractive errors in eyes with prior laser in situ keratomileusis (LASIK) and determine the most appropriate course of action for patients. METHODS:A review of all patients undergoing LASIK enhancement at a single refractive surgery center between 2012 and 2017 was undertaken. Refraction and biomicroscopy results before and after enhancement were collated and analyzed according to the method of enhancement (flap lift or surface ablation). RESULTS:A total of 108 eyes were included in the analysis; 58 eyes underwent flap lift and 50 underwent surface ablation retreatment with mean times to enhancement of 22.3 and 53.2 months, respectively. The mean spherical equivalent prior to enhancement was -0.43 ± 0.69 and -1.03 ± 1.01 diopters (D) for the flap lift and surface ablation groups, respectively. The absolute difference from intended refraction was statistically significant (lift 0.16 ± 0.24 versus surface ablation 0.31 ± 0.35 D; P = .01). The difference was more pronounced for eyes with prior hyperopia (P = .041). The incidence of haze following re-treatment was 3.4% in the flap lift group versus 10.0% in the surface ablation group, and 8.6% of the flap lift group had evidence of epithelial ingrowth, with 1 eye requiring washout. There was no correlation between time to enhancement, refraction, and incidence of complications following the enhancement procedure. CONCLUSIONS:There has been a trend toward treating residual LASIK refractive error through surface ablation. This review suggests that flap lift may result in a more accurate refractive outcome, albeit with an expected greater risk of epithelial ingrowth. [J Refract Surg. 2020;36(1):6-11.]

Comparison of Hill-radial basis function, Barrett Universal and current third generation formulas for the calculation of intraocular lens power during cataract surgery

© 2017 Royal Australian and New Zealand College of Ophthalmologists Importance: This study represents a novel comparison of recently introduced intraocular lens power calculation formulas. Background: To compare current new generation formulas for calculating the intraocular lens power for a standard cohort of patients undergoing cataract and lens replacement surgery in a private group practice in Australia. Design: Retrospective case series comparison. Participants: Postoperative results from 400 consecutive patients undergoing implantation of an SN60WF intraocular lens post cataract removal by 12 surgeons were used. Methods: Refractive outcomes were compared with expected targets to determine the predicted refractive outcomes using the Hill-radial basis function, Barrett Universal II and readily available third or fourth generation intraocular lens power calculation formulas. Main Outcome Measure: Mean absolute predicted error. Results: The mean absolute predicted difference ranged from 0.30 to 0.34 D. There was no overall significant difference in the predicted difference or variance between formulas. All formulas achieved greater than 78.3% of eyes within ±0.5 D of intended refraction. The Hill-radial basis function and Barrett formulas provided the lowest mean numerical error compared with existing formulas in short and long eyes, respectively. The Barrett Universal II formula had the lowest percentage of refractive surprises (>1 D from predicted error) across all axial lengths. Conclusions and Relevance: Acceptable outcomes can be achieved with optical biometry, consistent surgical technique and use of current intraocular lens power calculation formulas. The Barrett Universal II formula may provide the lowest risk of refractive surprise compared with other intraocular lens power calculation formulas

Update and clinical utility of the LenSx femtosecond laser in cataract surgery

Timothy V Roberts,1,2 Michael Lawless,1,2 Gerard Sutton,1,2 Chris Hodge1,3 1Vision Eye Institute, Chatswood, 2Sydney Medical School, University of Sydney, 3Graduate School of Health Sciences, University of Technology, Sydney, NSW, Australia Abstract: The introduction of femtosecond lasers to cataract surgery has been the major disruptive technology introduced into ophthalmic surgery in the last decade. Femtosecond laser cataract surgery (FLACS) integrates high-resolution anterior segment imaging with a femtosecond laser allowing key steps of cataract surgery to be performed with computer-guided laser accuracy, precision, and reproducibility. Since the introduction of FLACS, there have been significant advances in laser software and hardware as well as surgeon experience, with over 250 articles published in the peer-reviewed literature. This review examines the published evidence relating to the LenSx platform and discusses surgical techniques, indications, safety, and clinical results. Keywords: femtosecond laser, cataract surgery, LenSx, IO

Small incision lenticule extraction (SMILE) in 2015.

Small incision lenticule extraction (SMILE) represents a recent addition to the refractive surgeon's range of procedures. Although there remains a number of similarities to existing techniques in terms of patient selection and treatment parameters, consideration is required to optimise patient outcomes and satisfaction. Here, we review the selection criteria, contraindications, indications and existing published safety and efficacy outcomes

Assessment of corneal curvature using verion optical imaging system: a comparative study.

BACKGROUND: Keratometry is a critical determinant of the postoperative refractive outcome. This study evaluates the comparability of keratometry measurements obtained using the Verion Optical Imaging System with devices used in current clinical practice. Further, it determines the interobserver reliability of the Verion Optical Imaging System. DESIGN: Retrospective analysis of patient data PARTICIPANTS: Keratometric data was obtained from 100 patients presenting for pre-operative evaluation. Furthermore, repeatability and reproducibility were assessed using 15 healthy volunteers. METHODS: Corneal curvature values acquired by the Verion Optical Imaging System were compared with existing keratometry devices including autokeratometry, partial coherence interferometry (IOLMaster) and Scheimpflug corneal topography (Pentacam). MAIN OUTCOME MEASURES: Direct comparison of corneal power, cylinder, axis of astigmatism and vector analysis were performed using correlation and Bland-Altman analyses. Reproducibility and reliability of the device were assessed using within-subject standard deviation and intraclass correlation coefficients for experienced and inexperienced technicians. RESULTS: There was no statistically significant difference between Verion values and those obtained by other methods in relation to mean keratometry, corneal astigmatism, steep meridian and vector analyses (P > 0.05). Bland-Altman plots showed narrow limits of agreement for keratometry and astigmatism and wider agreement for steep meridian. Intraoperator reliability for both experienced and inexperienced operators and interoperator reproducibility showed no statistically significant differences between values. CONCLUSION: Measurements show no significant difference from those obtained by the other devices. This suggests the Verion system is en par with instruments used in current clinical practice. The Verion Optical Imaging System produces repeatable data with no difference related to operator experience

Total keratometry in intraocular lens power calculations in eyes with previous laser refractive surgery.

IMPORTANCE:Intraocular lens (IOL) calculations in post-refractive cases remain a concern. Our study identifies improved options for surgeons. BACKGROUND:To evaluate and compare the prediction accuracy of IOL power calculation methods after previous laser refractive surgery using standard keratometry (SK), measured posterior corneal astigmatism (PCA) and total keratometry (TK). DESIGN:Retrospective consecutive cohort. PARTICIPANTS:A total of 50 consecutive patients (72 eyes) at a private institution who underwent cataract surgery with prior laser refractive procedures. METHODS:Methods using SK included ASCRS mean, Barrett True-K no history, Haigis-L and Shammas IOL formulae. Barrett True-K using posterior values (True K TK), Haigis and Holladay 1 Double-K methods using TK were also assessed. Post-surgery refraction was undertaken at minimum 3 weeks following surgery. MAIN OUTCOME MEASURES:Arithmetic and absolute IOL refractive prediction errors, variances in mean arithmetic IOL prediction error, and percentage of eyes within ±0.25D, ±0.50D, ±0.75D and ±1.00D of refractive prediction errors were compared. RESULTS:The Barrett True-K (TK) provided the lowest mean refractive prediction error (RPE) and variance for both prior myopes and hyperopes undergoing cataract surgery. The Barrett True-K (TK) exhibited the highest percentages of eyes within ±0.50D, ±0.75D and ±1.00D of the RPE compared to other formulae for prior myopic patients. CONCLUSIONS AND RELEVANCE:Accuracy of IOL power calculations in post-laser eyes can be improved by the addition of posterior corneal values as measured by the IOLMaster 700. The use of total keratometry may supplement outcomes when no prior refraction history is known

Donation of discarded ocular tissue in patients undergoing SMILE laser refractive surgery: developing appropriate guidelines.

Tissue Biobanks represent an invaluable resource. Despite the majority of people supporting tissue donation, the actual rate remains low overall. Tissue discarded from surgical procedures represents a further avenue for collection for use in research. We aim to understand the information and consent requirements in a cohort of healthy, post-ophthalmic surgical subjects to optimise future tissue collection in living donors. Patients attending an ophthalmic clinic following refractive surgery for myopia (SMILE) were identified. Patient consent was implied with the completion of the provided survey. The questionnaire included gender, age range and education status. The majority of 31 subjects identified a benefit for future patients as the main motive for potential donation of discarded tissue (71%). Payment for the discarded tissue would not influence their decision in 77.4%. Explanation of the potential benefits of research was the most important information to consider before making a decision to donate. Only 12.9% of patients would have refused to include further information. Almost half of patients felt that the Biobank became the owner of tissue following donation. Current surgical patients may be more inclined to participate in research than the general public because of a sense of duty or an increased understanding of the role of research in evolving treatment. Despite minor uncertainty about the eventual use of the tissue and data, most subjects were positive to donation of discarded ocular tissue and de-identified information. Consent and education processes should be revised within an ophthalmic practice to minimise future patient anxiety