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.

/pdf/iol-power-calculations-and-cataract-surgery-in-eyes-with-1x6hnxsp.pdf

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

This prospective study evaluated the accuracy of IOL power calculation using ray tracing and formulas with and without total keratometry in eyes after SMILE. Purpose: To evaluate the prediction error (PE) variance and absolute median PE of different intraocular lens (IOL) calculation formulas including last-generation formulas such as Barrett True-K with K, Okulix and total keratometry (TK)-based calculations with Haigis, and Barrett True-K in a simulation model in post–small-incision lenticule extraction (SMILE) eyes. Settings: Department of Ophthalmology, University Hospital Marburg, Marburg, Germany. Design: Prospective study. Methods: Preoperative measurements included IOL power calculation before and after SMILE surgery. The target refraction was set to be the lowest myopic refractive error in pre-SMILE eyes. The IOL power targeting at the lowest myopic refractive error in pre-SMILE eyes was selected for the post-SMILE IOL calculation of the same eye. The difference between the predicted refraction of pre- and post-SMILE eyes with the same IOL power was defined as IOL difference. The refractive change induced by SMILE was defined as the difference between preoperative and postoperative manifest refraction. Results: 98 eyes from 49 patients underwent bilateral myopic SMILE. The PE variance of Okulix was not significantly different compared with Barrett True-K with TK (P = .471). The SDs of the mean PEs were ±0.413 D (Haigis-TK), ±0.453 D (Okulix), ±0.471 D (Barrett True-K with TK), ±0.556 D (Haigis-L), and ±0.576 D (Barrett True-K with K). The mean absolute PE was 0.340 D, 0.353 D, 0.404 D, 0.511 D, and 0.715 D for Haigis-TK, Okulix, Barrett True-K with TK, Barrett True-K with K, and Haigis-L, respectively. The highest percentage of eyes within ±0.50 D was achieved by Okulix, followed by Haigis-TK, Barrett True-K with TK, Barrett True-K with K, and Haigis-L. Conclusions: Results suggest that Haigis in combination with TK, Okulix, and Barrett True-K with and without TK offer good options for accurate IOL power calculation after SMILE. Haigis-L showed a tendency for myopic shift in eyes after previous SMILE.

Comparison of intraocular lens power calculation formulas with and without total keratometry and ray tracing in patients with previous myopic SMILE

Myopia is the leading cause of visual impairment in the world. With ever-increasing prevalence in these years, it creates an alarming global epidemic. In addition to the difficulty in seeing distant objects, myopia also increases the risk of cataract and advances its onset, greatly affecting the productivity of myopes of working age. Cataract management in myopic eyes, especially highly myopic eyes is originally more complicated than that in normal eyes, whereas the growing population of cataract with myopia, increasing popularity of corneal and lens based refractive surgery, and rising demand for spectacle independence after cataract surgery all further pose unprecedented challenges to ophthalmologists. Previous history of corneal refractive surgery and existence of implantable collamer lens will both affect the accuracy of biometry including measurement of corneal curvature and axial length before cataract surgery, which may result in larger intraocular lens (IOL) power prediction errors and a compromise in the surgical outcome especially in a refractive cataract surgery. A prudent choice of formula for cataract patients with different characteristics is essential in improving this condition. Besides, the characteristics of myopic eyes might affect the long-term stability of IOL, which is important for the maintenance of visual outcomes especially after the implantation of premium IOLs, thus a proper selection of IOL accordingly is crucial. In this mini-review, we provide an overview of the impact of myopia epidemic on treatment for cataract and to discuss new challenges that surgeons may encounter in the foreseeable future when planning refractive cataract surgery for myopic patients.

Challenges of refractive cataract surgery in the era of myopia epidemic: a mini-review

PURPOSE To evaluate the accuracy of the measurements of corneal power obtained by ray tracing with a combined Scheimpflug camera-Placido disk corneal topographer (Sirius) in eyes after small incision lenticule extraction for myopia (SMILE). METHODS Retrospective cases study includes 50 eyes of 50 patients who underwent myopic SMILE. Mean value of simulated keratometry (Kpost), mean pupil power (MPP) (ray tracing, diameter of the entrance pupil range 3-6 mm), anterior and posterior corneal radius, and corneal thickness were obtained with Sirius topographer preoperatively and three months postoperatively, as well as cycloplegic refraction. True net power, equivalent keratometry readings, and Haigis equivalent power formula were calculated, and these measurements, MPP and Kpost, were compared with the corneal power calculated with the clinical history method (CHM). RESULTS Corneal power measurements obtained with all methods were significantly different from CHM (P < 0.001), except the value of MPP obtained at 5.5 mm (P = 0.927). A good direct correlation was found between CHM and all measurements. The distribution of differences as compared with the CHM showed that the lowest difference corresponded to the value of MMP at 5.5 mm (- 0.002 ± 0.6). The Bland-Altman plots for the MPP at 5.5 mm showed 95% limits of agreement between - 1.1787 D and 1.1741 D. CONCLUSIONS MPP obtained by ray tracing within a diameter of entrance pupil of 5.5 mm could predict corrected corneal power derived from the CHM in eyes following SMILE surgery.

Corneal power measurements by ray tracing in eyes after small incision lenticule extraction for myopia with a combined Scheimpflug Camera-Placido disk topographer.

Introduction: This is a report of cataract surgery in a post–small-incision lenticule extraction (SMILE) patient with low myopia. Patient and clinical findings: A 49-year-old man underwent bilateral SMILE 18 months previously, and the visual acuity of both eyes recovered to 20/20. The patient noticed a gradual reduction in visual acuity in his left eye and blurring for 3 months. The corrected distance visual acuity (CDVA) was 20/67 in his left eye. Diagnosis, intervention, and outcomes: The slitlamp examination revealed an anterior subcapsular cataract. The intraocular lens (IOL) power was calculated by using a multiformula averaging method. A standard femtosecond laser–assisted phacoemulsification cataract surgery was performed and a trifocal IOL implanted. 2 months after IOL implantation, the uncorrected distance visual acuity of the left eye was 20/33, the autorefraction values were −1.37 −0.25 × 146, and the CDVA was 20/20. Conclusions: This case report showed that current postrefractive IOL power calculation formulas or methods may lead to myopic outcomes in patients who previously received SMILE. A standard IOL calculation may be more suitable for such patients. Additional case studies are needed to accurately calculate IOL power after SMILE similar to laser in situ keratomileusis.

https://doi.org/10.1097/j.jcro.0000000000000071

Myopic outcome after intraocular lens implantation in a patient who previously had small-incision lenticule extraction

PURPOSE To evaluate and compare the predictability of intraocular lens (IOL) power calculation after small-incision lenticule extraction (SMILE) for myopia and myopic astigmatism. SETTING Department of Ophthalmology, Philipps University of Marburg, Marburg, Germany. DESIGN Retrospective comparative case series. METHODS Preoperative evaluation included optical biometry using IOLMaster 500 and corneal tomography using Pentacam HR. The corneal tomography measurements were repeated at 3 months postoperatively. The change of spherical equivalent due to SMILE was calculated by the manifest refraction at corneal plane (SMILE-Dif). A theoretical model, involving the virtual implantation of the same IOL before and after SMILE, was used, and the IOL power calculations were performed using ray tracing (OKULIX, version 9.06) and third- (Hoffer Q, Holladay 1, and SRK/T) and fourth-generation (Haigis-L and Haigis) formulas. The difference between the IOL-induced refractive error at corneal plane before and after SMILE (IOL-Dif) was compared with SMILE-Dif. The prediction error (PE) was calculated as the difference between SMILE-Dif-IOL-Dif. RESULTS The study included 204 eyes that underwent SMILE. The PE with ray tracing was -0.06 ± 0.40 diopter (D); Haigis-L, -0.39 ± 0.62 D; Haigis, 0.70 ± 0.48 D; Hoffer Q, 0.84 ± 0.47 D; Holladay 1, 1.21 ± 0.51 D; and SRK/T, 1.46 ± 0.54 D. The PE with ray tracing was significantly smaller compared with that of all formulas (P ≤ .001). The PE variance with ray tracing was σ2 = 0.159, being significantly more homogenous compared with that of all formulas (P ≤ .011, F ≥ 6.549). Ray tracing resulted in an absolute PE of 0.5 D or lesser in 81.9% of the cases, followed by Haigis-L (53.4%), Haigis (35.3%), Hoffer Q (25.5%), Holladay 1 (6.4%), and SRK/T (2.9%) formulas. CONCLUSIONS Ray tracing was the most accurate approach for IOL power calculation after myopic SMILE.

Predictability of intraocular lens power calculation after small-incision lenticule extraction for myopia.

BACKGROUND
Kidney graft rejections are classified based on the Banff classification. The RejectClass algorithm, initially derived from a cohort comprising mostly protocol biopsies, identifies data-driven phenotypes of acute rejection and chronic pathology using Banff lesion scores. It also provides composite scores for inflammation activity and chronicity. This study independently evaluates the performance of RejectClass in a cohort consisting entirely of indication biopsies.


METHODS
We retrospectively applied RejectClass to 441 patients from the German TRABIO (TRAnsplant BIOpsies) cohort who had received indication biopsies. The primary endpoint was death-censored graft failure during 2 y of follow-up.


RESULTS
The application of RejectClass to our cohort demonstrated moderately comparable phenotypic features with the derivation cohort, and most clusters indicated an elevated risk of graft loss. However, the reproduction of all phenotypes and the associated risks of graft failure, as depicted in the original studies, was not fully accomplished. In contrast, adjusted Cox proportional hazards analyses substantiated that both the inflammation score and the chronicity score are independently associated with graft loss, exhibiting hazard ratios of 1.7 (95% confidence interval, 1.2-2.3; P = 0.002) and 2.2 (95% confidence interval, 1.8-2.6; P < 0.001), respectively, per 0.25-point increment (scale: 0.0-1.0).


CONCLUSIONS
The composite inflammation and chronicity scores may already have direct utility in quantitatively assessing the disease stage. Further refinement and validation of RejectClass clusters are necessary to achieve more reliable and accurate phenotyping of rejection.

Potential and Uncertainties of RejectClass in Acute Kidney Graft Dysfunction: An Independent Validation Study.

Introduction Despite continued efforts, long-term outcomes of kidney transplantation remain unsatisfactory. Kidney graft rejections are independent risk factors for graft failure. At the participating centres of the TRAnsplant BIOpsies study group, a common therapeutic standard has previously been defined for the treatment of graft rejections. The outcomes of this strategy will be assessed in a prospective, observational cohort study. Methods and analysis A total of 800 kidney transplantation patients will be enrolled who undergo a graft biopsy because of deteriorating kidney function. Patients will be stratified according to the Banff classification, and the influence of the treatment strategy on end points will be assessed using regression analysis. Primary end points will be all-cause mortality and graft survival. Secondary end points will be worsening of kidney function (≥30% decline of estimated Glomerular Filtration Rate [eGFR] or new-onset large proteinuria), recurrence of graft rejection and treatment response. Baseline data and detailed histopathology data will be entered into an electronic database on enrolment. During a first follow-up period (within 14 days) and subsequent yearly follow-ups (for 5 years), treatment strategies and clinical course will be recorded. Recruitment at the four participating centres started in September 2016. As of August 2020, 495 patients have been included. Ethics and dissemination Ethical approval for the study has been obtained from the ethics committee of Kiel (AZ B 278/16) and was confirmed by the committees of Munich, Mainz and Stuttgart. The results will be reported in a peer-reviewed journal, according to the Strengthening the Reporting of Observational Studies in Epidemiology criteria. Trial registration number ISRCTN78772632; Pre-results.

/pdf/study-protocol-the-transplant-biopsies-trabio-study-a-c79g72dx.pdf

Study protocol: the TRAnsplant BIOpsies (TRABIO) study – a prospective, observational, multicentre cohort study to assess the treatment of kidney graft rejections

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Papers

Predictability of intraocular lens power calculation after small-incision lenticule extraction for myopia.

Potential and Uncertainties of RejectClass in Acute Kidney Graft Dysfunction: An Independent Validation Study.

Study protocol: the TRAnsplant BIOpsies (TRABIO) study – a prospective, observational, multicentre cohort study to assess the treatment of kidney graft rejections