Effects of large-scale gold mining on habitat use and selection by American pronghorn.

Anthropogenic disturbances, including extraction of natural resources and development of alternative energy, are reducing and fragmenting habitat for wildlife across the globe. Effects of those disturbances have been explored by studying populations that migrate through oil and gas fields or alternative energy facilities. Extraction of minerals, including precious metals and lithium, is increasing rapidly in remote areas, which results in dramatically altered landscapes in areas of resident populations of wildlife. Our goal was to examine how a resident population of American pronghorn (Antilocapra americana) in the Great Basin ecosystem selected resources near a large-scale disturbance year around. We investigated how individuals selected resources around a large, open-pit gold mine. We classified levels of disturbance associated with the mine, and used a random forest model to select ecological covariates associated with habitat selection by pronghorn. We used resource selection functions to examine how disturbances affected habitat selection by pronghorn both annually and seasonally. Pronghorn strongly avoided areas of high disturbance, which included open pits, heap leach fields, rock disposal areas, and a tram. Pronghorn selected areas near roads, although selection was strongest about 2 km away. We observed relatively broad variation among individuals in selection of resources, and how they responded to the mine. The Great Basin is a mineral-rich area that continues to be exploited for natural resources, especially minerals. Sagebrush-dependent species, including pronghorn, that rely on this critical habitat were directly affected by that transformation of the landscape, which is likely to increase with expansion of the mine. As extraction of minerals from remote landscapes around the world continues to fragment habitats for wildlife, increasing our understanding of impacts of those changes on behaviors of wildlife before populations decline, may assist in the mitigation and minimization of negative impacts on mineral-rich landscapes and on wildlife populations.

Changes in selection of resources with reproductive state in a montane ungulate.

Animals select habitats based on food, water, space, and cover. Each of those components are essential to the ability of an individual to survive and reproduce in a particular habitat. Selection of resources is linked to reproductive fitness and individuals likely vary in how they select resources relative to their reproductive state: during pregnancy, while provisioning young when nutritional needs of the mother are high, but offspring are vulnerable to predation, or if they lose young to mortality. We investigated the effects of reproductive state on selection of resources by maternal female desert bighorn sheep (Ovis canadensis nelsoni) by comparing selection during the last trimester of gestation, following parturition when females were provisioning dependent young, and if the female lost an offspring. We captured, and recaptured each year, 32 female bighorn sheep at Lone Mountain, Nevada, during 2016-2018. Captured females were fit with GPS collars and those that were pregnant received vaginal implant transmitters. We used a Bayesian approach to estimate differences in selection between females provisioning and not provisioning offspring, as well as the length of time it took for females with offspring to return levels of selection similar to that observed prior to parturition. Females that were not provisioning offspring selected areas with higher risk of predation, but greater nutritional resources than those that were provisioning dependent young. When females were provisioning young immediately following parturition, females selected areas that were safe from predators, but had lower nutritional resources. Females displayed varying rates of return to selection strategies associated with access to nutritional resources as young grew and became more agile and less dependent on mothers. We observed clear and substantial shifts in selection of resources associated with reproductive state, and females exhibited tradeoffs in favor of areas that were safer from predators when provisioning dependent young despite loss of nutritional resources to support lactation. As young grew and became less vulnerable to predators, females returned to levels of selection that provided access to nutritional resources to restore somatic reserves lost during lactation.

SMILE for Hyperopia With and Without Astigmatism: Results of a Prospective Multicenter 12-Month Study.

PURPOSE: To investigate the safety and effectiveness of small incision lenticule extraction (SMILE) in patients who have hyperopia with or without astigmatism. METHODS: This was a prospective multicenter trial including 374 eyes of 199 patients treated by SMILE for hyperopia using the VisuMax femtosecond laser (Carl Zeiss Meditec AG). Inclusion criteria were sphere up to +6.00 diopters (D), cylinder up to 5.00 D, and maximum hyperopic meridian up to +7.00 D, with preoperative corrected distance visual acuity (CDVA) of 20/25 or better. The optical zone was 6.3 mm with a transition zone of 2 mm. The minimum lenticule thickness was set at 25 µm in the center and at 10 µm at the edge. Patients were examined at 1 day, 1 week, and 1, 3, 6, 9, and 12 months after surgery. Standard refractive surgery outcomes analysis was performed. RESULTS: The preoperative spherical equivalent was +3.20 ± 1.48 D (range: +0.25 to +6.50 D). At the 12-month follow-up visit, 81% of eyes treated were within ±0.50 D and 93% of eyes were within ±1.00 D of intended correction. A total of 1.2% of eyes lost two or more lines of CDVA at the 12-month follow-up visit, and 83% were at least 20/20, corresponding to a safety index of 1.005 at 12 months. Of the 219 eyes with plano target, 68.8% had an uncorrected distance visual acuity of 20/20 or better and 88% were at least 20/25 uncorrected at 12 months. There were no statistically significant changes in contrast sensitivity. CONCLUSIONS: SMILE was found to be an effective treatment method for the correction of compound hyperopic astigmatism, demonstrating a high level of efficacy, predictability, safety, and stability. [J Refract Surg. 2022;38(12):760-769.].

Retinal Vascular Occlusion after COVID-19 Vaccination: More Coincidence than Causal Relationship? Data from a Retrospective Multicentre Study.

BACKGROUND: To investigate whether vaccination against SARS-CoV-2 is associated with the onset of retinal vascular occlusive disease (RVOD). METHODS: In this multicentre study, data from patients with central and branch retinal vein occlusion (CRVO and BRVO), central and branch retinal artery occlusion (CRAO and BRAO), and anterior ischaemic optic neuropathy (AION) were retrospectively collected during a 2-month index period (1 June-31 July 2021) according to a defined protocol. The relation to any previous vaccination was documented for the consecutive case series. Numbers of RVOD and COVID-19 vaccination were investigated in a case-by-case analysis. A case-control study using age- and sex-matched controls from the general population (study participants from the Gutenberg Health Study) and an adjusted conditional logistic regression analysis was conducted. RESULTS: Four hundred and twenty-one subjects presenting during the index period (61 days) were enrolled: one hundred and twenty-one patients with CRVO, seventy-five with BRVO, fifty-six with CRAO, sixty-five with BRAO, and one hundred and four with AION. Three hundred and thirty-two (78.9%) patients had been vaccinated before the onset of RVOD. The vaccines given were BNT162b2/BioNTech/Pfizer (n = 221), followed by ChadOx1/AstraZeneca (n = 57), mRNA-1273/Moderna (n = 21), and Ad26.COV2.S/Johnson & Johnson (n = 11; unknown n = 22). Our case-control analysis integrating population-based data from the GHS yielded no evidence of an increased risk after COVID-19 vaccination (OR = 0.93; 95% CI: 0.60-1.45, p = 0.75) in connection with a vaccination within a 4-week window. CONCLUSIONS: To date, there has been no evidence of any association between SARS-CoV-2 vaccination and a higher RVOD risk.

Linking population performance to nutritional condition in an alpine ungulate.

Bighorn sheep (Ovis canadensis) can live in extremely harsh environments and subsist on submaintenance diets for much of the year. Under these conditions, energy stored as body fat serves as an essential reserve for supplementing dietary intake to meet metabolic demands of survival and reproduction. We developed equations to predict ingesta-free body fat in bighorn sheep using ultrasonography and condition scores in vivo and carcass measurements postmortem. We then used in vivo equations to investigate the relationships between body fat, pregnancy, overwinter survival, and population growth in free-ranging bighorn sheep in California and Nevada. Among 11 subpopulations that included alpine winter residents and migrants, mean ingesta-free body fat of lactating adult females during autumn ranged between 8.8% and 15.0%; mean body fat for nonlactating females ranged from 16.4% to 20.9%. In adult females, ingesta-free body fat > 7.7% during January (early in the second trimester) corresponded with a > 90% probability of pregnancy and ingesta-free body fat > 13.5% during autumn yielded a probability of overwinter survival > 90%. Mean ingesta-free body fat of lactating females in autumn was positively associated with finite rate of population increase (λ) over the subsequent year in bighorn sheep subpopulations that wintered in alpine landscapes. Bighorn sheep with ingesta-free body fat of 26% in autumn and living in alpine environments possess energy reserves sufficient to meet resting metabolism for 83 days on fat reserves alone. We demonstrated that nutritional condition can be a pervasive mechanism underlying demography in bighorn sheep and characterizes the nutritional value of their occupied ranges. Mountain sheep are capital survivors in addition to being capital breeders, and because they inhabit landscapes with extreme seasonal forage scarcity, they also can be fat reserve obligates. Quantifying nutritional condition is essential for understanding the quality of habitats, how it underpins demography, and the proximity of a population to a nutritional threshold.

10-Year Results of FLEx Refractive Surgery.

PURPOSE: To evaluate the 10-year results of femtosecond lenticule extraction (FLEx) for treatment of myopia and myopic astigmatism. METHODS: This long-term follow-up of a prospective clinical trial was conducted at HELIOS Klinikum Erfurt and Phillips University of Marburg, Germany. In 2006, 108 eyes underwent the FLEx procedure. All patients were invited for reexamination 10 years after FLEx treatment for myopia and astigmatism. Visual acuity, objective and manifest refraction, intraocular pressure, and slit-lamp examination and side effects were documented. Main outcome measures were uncorrected (UDVA) and corrected (CDVA) distance visual acuity, objective and manifest refraction, and slit-lamp examination and side effects. RESULTS: A total of 77 eyes of 40 patients of the original treatment group volunteered for a reexamination 10 years after surgery. The mean age of the patients was 45.9 years; 26 were women and 14 were men. UDVA was 0.09 ± 0.19 logMAR and CDVA was stable at -0.1 ± 0.09 logMAR. More than half of the eyes gained one or two Snellen lines, and none of the eyes lost two or more lines. Over the 10-year period, regression was 0.18 D. CONCLUSIONS: FLEx has stable results 10 years after treatment for myopia and astigmatism. [J Refract Surg. 2019;35(11):707-711.].

10-Year Results of Small Incision Lenticule Extraction.

PURPOSE: To evaluate the 10-year results of refractive lenticule extraction using the small incision lenticule extraction (SMILE) technique for treatment of myopia and myopic astigmatism. METHODS: In 2008-2009, the first 91 eyes were treated using a novel surgical technique (SMILE), in which a refractive lenticule of intrastromal corneal tissue is removed through a small incision, completely eliminating flap cutting. A total of 56 of 91 eyes of the original treatment group volunteered for reexamination 10 years after surgery, including uncorrected and corrected distance visual acuity, objective and manifest refraction, and evaluation of the interface and corneal surface by slit-lamp examination. Late side effects such as corneal scarring, corneal ectasia, persistent dry eye symptoms, or cataract were documented. RESULTS: At 10 years postoperatively, there was no significant change from the 6-month results. Spherical equivalent was -0.35 ± 0.66 diopters and therefore close to target refraction. Sixteen of the 56 eyes (29%) had gained one to two Snellen lines. There was no loss of two or more lines in the long term. Regression was -0.35 ± 0.66 diopters over the 10-year period. CONCLUSIONS: This 10-year long-term study demonstrates SMILE to be an effective, stable, and safe procedure for the treatment of myopia and myopic astigmatism. [J Refract Surg. 2019;35(10):618-623.].

A machine-learning approach for extending classical wildlife resource selection analyses.

Resource selection functions (RSFs) are tremendously valuable for ecologists and resource managers because they quantify spatial patterns in resource utilization by wildlife, thereby facilitating identification of critical habitat areas and characterizing specific habitat features that are selected or avoided. RSFs discriminate between known-use resource units (e.g., telemetry locations) and available (or randomly selected) resource units based on an array of environmental features, and in their standard form are performed using logistic regression. As generalized linear models, standard RSFs have some notable limitations, such as difficulties in accommodating nonlinear (e.g., humped or threshold) relationships and complex interactions. Increasingly, ecologists are using flexible machine-learning methods (e.g., random forests, neural networks) to overcome these limitations. Herein, we investigate the seasonal resource selection patterns of mule deer (Odocoileus hemionus) by comparing a logistic regression framework with random forest (RF), a popular machine-learning algorithm. Random forest (RF) models detected nonlinear relationships (e.g., optimal ranges for slope and elevation) and complex interactions which would have been very challenging to discover and characterize using standard model-based approaches. Compared with standard RSF models, RF models exhibited improved predictive skill, provided novel insights about resource selection patterns of mule deer, and, when projected across a relevant geographic space, manifested notable differences in predicted habitat suitability. We recommend that wildlife researchers harness the strengths of machine-learning tools like RF in addition to "classical" tools (e.g., mixed-effects logistic regression) for evaluating resource selection, especially in cases where extensive telemetry data sets are available.

Femtosecond Lenticule Extraction (FLEx) for Spherocylindrical Hyperopia Using New Profiles.

PURPOSE: To investigate new lenticule profiles for the treatment of hyperopia by femtosecond lenticule extraction (FLEx) for spherocylindrical hyperopia using a modified laser scan sequence. METHODS: In this prospective 9-month study, 39 eyes of 22 patients with the mean age of 49 years (range: 27 to 56 years) underwent hyperopic FLEx. The mean optical zone was 6 mm (range: 5.75 to 6.75 mm) with keratometry readings and magnitude of correction adjusted mean transition zone of 2.1 mm (range: 1.80 to 2.89 mm). The lenticule thickness was set at 25 µm in the center and 10 µm at the edge. RESULTS: Preoperative spherical equivalent manifest refraction was +1.96 ± 1.04 diopters (D) (range: +0.63 to +4.50 D). Because of the presbyopic age, the treatment was aimed at low myopia in 75% of the eyes treated. At the final 9-month follow-up visit, the mean spherical equivalent was -0.40 ± 0.61 D (range: -1.50 to +0.75 D), with 70% of eyes treated within ±0.50 D and 89% of eyes within ±1.00 D of intended correction. The regression was +0.29 D between 1 week and 6 months but 0.03 D between 6 and 9 months. A total of 10% of eyes lost one line of corrected distance visual acuity, respectively. There were no losses of two or more lines of visual acuity or any serious intraoperative or postoperative complications. CONCLUSIONS: Treatment of spherocylindrical hyperopia by FLEx led to refractive results similar to published outcomes on hyperopic femtosecond laser-assisted LASIK. [J Refract Surg. 2018;34(1):6-10.].

Repeatability and agreement in optical biometry of a new swept-source optical coherence tomography-based biometer versus partial coherence interferometry and optical low-coherence reflectometry.

PURPOSE: To estimate the repeatability of biometric parameters obtained with a new swept-source biometer and to compare the agreement with that of partial coherence interferometry (PCI) and optical low-coherence reflectometry (OLCR). SETTING: Department of Ophthalmology, Helios Hospital Erfurt, Erfurt, Julius-Maximilians University, Würzburg, and Philipps University, Marburg, Germany. DESIGN: Prospective comparative multicenter clinical study. METHODS: Biometry was taken with the use of 3 different biometers: the IOLMaster 700 swept-source biometer, the PCI-based IOLMaster 500, and the OCLR-based Lenstar LS 900. Axial length (AL), anterior chamber depth (ACD), and spherical equivalent (SE) were compared between swept-source and PCI biometry and central corneal thickness (CCT) and lens thickness (LT) between swept-source and OLCR biometry. The repeatability of swept-source biometry was evaluated on the basis of 3 measurements captured for each patient. RESULTS: One hundred twenty cataract eyes were included in the study. The mean difference between swept-source and PCI biometry for AL, ACD, and SE measurements was 4 µm ± 25 (SD), 17 ± 122 µm, and -0.001 ± 0.19 diopter (D), respectively. The mean difference between swept-source and OLCR biometry for LT and CCT measurements was 21 ± 122 µm and 0.15 ± 4.51 µm, respectively. Differences between swept-source biometry and the other devices distributed around zero without statistical significance. The standard deviation of repeatability for AL, ACD, LT, CCT, and SE was 8.8 µm, 9.8 µm, 2.3 µm, 19.5 µm, and 0.1 D, respectively. CONCLUSIONS: Swept-source biometry showed high repeatability performance for all biometric parameters. The agreement of AL, ACD, and SE between swept-source and PCI biometry as well as that of LT and CCT between swept-source and OLCR biometry was excellent. It remains to be validated whether high repeatability shown by swept-source biometry will result in better postoperative refractive outcomes. FINANCIAL DISCLOSURE: Drs. Blum and Sekundo are members of the Scientific Advisory Board of Carl Zeiss Meditec AG. Drs. Peter and Bühren are employees of Carl Zeiss Meditec AG.

Improved lenticule shape for hyperopic femtosecond lenticule extraction (ReLEx FLEx): a pilot study.

The aim of this study is to establish and to prove a new lenticule shape for the treatment of hyperopia using a 500 kHz femtosecond laser and the femtosecond lenticule extraction (ReLEx FLEx) technique. Improved lenticule shapes with a large transition zone of at least 2 mm adjusted to the 5.75 mm optical zone were designed. A prospective pilot study on nine eyes of five patients who underwent an uncomplicated FLEx using VisuMax femtosecond laser (Carl Zeiss Meditec AG) for spherical hyperopia was performed. Patients' mean age was 55.5 years, and the preoperative manifest spherical equivalent (SE) was +1.82 D (range +1.25 to +3.00 D). Because of the presbyopic age and in order to compensate for a possible regression, the treatment was aimed at low myopia (mean target SE was -0.88 D with a mean treatment refraction of +2.69 D). At the last follow-up, after 9 months, 33% were within ±0.50 D and 78% within ±1.00 D of intended correction. Thirty-three percent lost one line, and 11% gained one line corrected distance visual acuity (CDVA). On average, the centre of the optical zone was 0.34 ± 0.17 mm from the corneal vertex. No adverse effects were observed. This pilot study confirms that the improved lenticule's design with a large optical and transition zone can achieve good centration and acceptable results for spherical hyperopia using FLEx. The next steps are to extend the study to spherocylindrical hyperopic treatments and to increase the number of eyes for better assessment of refractive outcome.

Five-year results of Small Incision Lenticule Extraction (ReLEx SMILE).

BACKGROUND: To evaluate the 5-year results of Refractive Lenticule Extraction (ReLEx) as Small Incision Lenticule Extraction (SMILE) technique for treatment of myopia and myopic astigmatism. METHODS: In 2008/2009, the worldwide first 91 eyes were treated using a novel surgical technique (SMILE), where a refractive lenticule of intrastromal corneal tissue is removed though a small incision completely eliminating flap-cutting. 56 out of 91 eyes of the original treatment group volunteered for re-examination 5 years after surgery. Uncorrected distance visual acuity and corrected distance visual acuity after 5 years, objective and manifest refractions as well as evaluation of the interface and corneal surface by slit-lamp examination were documented. Late side effects like corneal scars, corneal ectasia, persistent dry eye symptoms or cataract were documented. RESULTS: 5 years postoperatively, no significant change to the 6-month data was found. Spherical equivalent was -0.375 D and therefore close to target refraction (emmetropia). 32 of the 56 eyes had gained 1-2 Snellen lines. There was no loss of 2 or more lines over the 5-year period. Regression in the long term was 0.48 D. CONCLUSIONS: This first long-term study demonstrates SMILE to be an effective, stable and safe procedure for treatment of myopia and myopic astigmatism. CLINICAL TRIAL NUMBER: DE/CA93/KP/07/001. Post-results.

Foveal pit morphology evaluation during optical biometry measurements using a full-eye-length swept-source OCT scan biometer prototype.

PURPOSE: To assess the scan quality of foveal pit morphology (FPM) and to quantify central retinal thickness (CRT) during routine optical biometry measurements with a full-eye-length swept-source optical coherence tomography (SS-OCT) scan biometer prototype (IOLMaster700) and to compare these results with standard examinations using spectral-domain optical coherence tomography (SD-OCT) technique (Cirrus4000 SD-OCT). METHODS: As part of a SS-OCT scan protocol to measure biometric parameters for intraocular lens power calculation, central horizontal 1 mm retinal B scans were taken from phakic (group I) and pseudophakic (group II) nonvitrectomized eyes. To evaluate FPM, macular scans of either examination technique were subjectively analyzed and compared. Repeated CRT measurements were performed to analyze repeatability and consistency of IOLMaster700 recordings. These results were compared with CRT evaluations using SD-OCT. RESULTS: Overall, 146 eyes of 146 patients were included in this series. The subjective assessments of FPM are illustrated. Repeated CRT measurements (repeatability) with the IOLMaster700 disclosed an overall intraclass correlation of 0.57 (group I: 0.48; group II: 0.89). Overall coefficient of variation (accuracy) was calculated to be 12.43% (group I: 14.21%; group II: 5.66%). The comparison of CRT measurements between both devices showed significant differences in group I (p = 0.006). CONCLUSIONS: Compared with SD-OCT, resolution of the 1 mm retinal B scan of SS-OCT scan biometry was lower. However, advanced pathologic characteristics were clearly discernible. Repeatability and accuracy of CRT measurements were acceptable though lower than with the standard SD-OCT technique. The CRT differed significantly in eyes of particular interest (group I) between both devices. The new scan could provide useful information for subsequent patient examination and further treatment planning for cataract surgery.

Five-year results of refractive lenticule extraction.

PURPOSE: To evaluate the 5-year results of femtosecond laser-assisted refractive lenticule extraction (ReLEx-FLEx) for the treatment of myopia and myopic astigmatism. SETTING: Departments of Ophthalmology, Helios Klinikum Erfurt, Erfurt, and Phillips Universität Marburg, Marburg, Germany. DESIGN: Prospective clinical trial. METHODS: This was a follow-up of a prospective study that evaluated the first patients treated with refractive lenticule extraction, in which a flap and a refractive lenticule of intrastromal corneal tissue were simultaneously cut using a 200 kHz Visumax femtosecond laser system. Thereafter, the lenticule was manually removed and the flap repositioned. The main outcome measures were the uncorrected and corrected distance visual acuities, objective and manifest refractions, slitlamp examination findings, and side effects after 5 years. RESULTS: Forty-one of 108 eyes in the original treatment group were available for a reexamination. Five years postoperatively, 100% of eyes were within ±1.00 diopter (D) of the intended correction and 73% were within ±0.50 D. By 5 years, no eye had lost 2 or more Snellen lines and 1 eye had lost 1 Snellen line. The mean regression was 0.07 D. CONCLUSION: Long-term data indicate that refractive lenticule extraction is an effective and safe procedure for the treatment of myopia and myopic astigmatism and has excellent stability. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

A modified Hartmann-Shack aberrometer for measuring stray light in the anterior segment of the human eye.

PURPOSE: To examine the use of a modified Hartmann-Shack wave front aberrometer (WASCA; Carl Zeiss Meditec AG, Germany) to measure objective stray light caused by forward light scatter from the anterior segment of the human eye. SETTING: HELIOS Klinikum Erfurt/Institute of Biomedical Engineering and Informatics, Ilmenau University of Technology, Germany. METHOD: Scatter parameters, including the Michelson contrast and cross-sectional area at half height (CAHM) were examined in Hartmann-Shack images from ten subjects with a cataract in one eye and an intraocular lens (IOL) in the other. The parameters were compared between each eye. Light scatter was then measured in 40 healthy subjects (age range, 23-75 years) with spherical ametropia ranging from -0.25 to 0.25 diopters. The subjects were divided into three age groups; 23-35, 36-50, and 51-75 years. Light scatter was also measured using four alternative methods. RESULTS: CAHM and contrast were significantly different between the eyes with the cataract and the IOL (P = 0.007 and P = 0.004, respectively). CAHM (r = 0.557, P < 0.001) and contrast (r = -0.467, P < 0.001) were both significantly correlated with age. There were significant differences in CAHM and contrast between the age groups. CONCLUSION: The modified wave front aberrometer can be used to measure stray light, although its diagnostic sensitivity in individual patients must be improved.

Vector analysis of myopic astigmatism corrected by femtosecond refractive lenticule extraction.

PURPOSE: To evaluate the visual outcome of refractive lenticule extraction in eyes with myopic astigmatism using the Visumax femtosecond laser. SETTING: Department of Ophthalmology, HELIOS Klinikum Erfurt, Erfurt, Germany. DESIGN: Nonrandomized clinical trials. METHODS: The data set encompassed treatments of sphere and astigmatism. Vector analysis was performed to study the astigmatic results at each follow-up visit at 1 week and 1, 3, and 6 months. Visual outcomes were analyzed for the 6-month follow-up period. RESULTS: The data evaluated was a complete set of refractive data of 182 treatments (87 left eyes, 95 right eyes). Efficacy, predictability, and safety with regard to astigmatic correction were comparable to the results with U.S. Food and Drug Administration-approved excimer lasers. At 6 months, the mean error ratio was 0.68 ± 0.75 (SD) and the mean correction ratio was 1.11 ± 0.69. There was slight astigmatic undercorrection (approximately 10%) over time. The residuum of the linear regression analysis of the predictability plot was approximately 0.4 diopter. Ninety-six percent of the eyes had a corrected distance visual acuity (CDVA) of 20/20 or better; no eye had a CDVA worse than 20/32. CONCLUSION: Femtosecond refractive lenticule extraction is an effective procedure for correcting myopic astigmatism.