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Copyright of Arquivos Brasileiros de Oftalmologia is the property of Arquivos Brasileiros de Oftalmologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We reported a case of rapidly developed corneal epithelial in-growth (EI) deteriorating visual acuity (VA) within the initial postoperative day. A 37-year-old male presented with decreased VA for 2 years. He underwent LASIK surgery 13 years ago. After enhancement surgery, postoperative VA was much worse than preoperative best corrected visual acuity (BCVA) 20/20 and decreased rapidly. VA of OD was 20/40 on Day 1, and 20/70 on Day 5, OS 20/20 on Day 1, 20/25 on Day 10, and 20/50 on Day 13 postoperatively. Corneal topography and optical coherence tomography (OCT) showed distinctive features. The patient was diagnosed with corneal EI postoperatively. After scraping ectopic corneal epithelial cells, the cornea became transparent and VA improved. Despite its rarity, early postoperative EI can occur within 1 day after enhancement surgery and can progress rapidly. OCT and corneal topography provide distinctive manifestations aiding diagnosis. [ABSTRACT FROM AUTHOR]

Copyright of Arquivos Brasileiros de Oftalmologia is the property of Arquivos Brasileiros de Oftalmologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Jun Zhang, Li Zheng, Chenyao Zheng, Peihong Sun Department of Ophthalmology, Hangzhou MSK Eye Hospital, Hangzhou, People’s Republic of ChinaCorrespondence: Jun Zhang, Email zhangjun@mskyk.onaliyun.comPurpose: This study was designed to compare the clinical outcomes of three cylindrical treatment strategies using manifest, topographic, and Zhang & Zheng vector-compensated refraction (ZZ VR) cylinders, for topography-guided laser-assisted in situ keratomileusis (LASIK) and to identify the laser programming strategy that optimizes refractive astigmatism outcomes and visual acuity.Methods: Consecutive patients referred for therapeutic refractive surgery between March and September 2018 at a single center were prospectively analyzed. Using double-masked simple randomization, patients were randomly assigned to undergo treatment based on manifest cylinder, topographic cylinder, and ZZ VR cylinder strategies. Uncorrected distance visual acuity and astigmatic refraction were analyzed preoperatively and 6 months postoperatively.Results: A total of 138 eyes from 71 patients met the inclusion criteria. The manifest group consisted of 46 eyes in 24 patients, the topographic group consisted of 43 eyes in 22 patients, and the ZZ VR group consisted of 49 eyes in 25 patients. The absolute residual cylindrical refractions at 6 months postoperatively in these three groups were 0.69 ± 0.32 D, 0.58 ± 0.31 D, and 0.42 ± 0.19 D, respectively (P < 0.001; adjusted P < 0.01 for manifest vs ZZ VR, adjusted P = 0.08 for topographic vs ZZ VR). The percentages of postoperative absolute residual cylindrical power within 0.50 D in the manifest, topographic, and ZZ VR groups were 30.4%, 55.8%, and 59.2%, respectively (P = 0.01; adjusted P = 0.06 for manifest vs topographic, adjusted P = 0.02 for manifest vs ZZ VR).Conclusion: The ZZ VR strategy may achieve better outcomes, as determined by cylindrical correction and visual activity, during topography-guided LASIK.Clinical Trial Registration Number: ChiCTR1900025779.Keywords: astigmatism, corneal wavefront aberration, keratomileusis, laser in situ, refraction

ABSTRACT LASIK is a refractive surgical procedure in which a corneal flap is created to expose the corneal stromal bed. Preoperative estimation of corneal flap thickness is necessary to calculate the percentage tissue altered in LASIK, an important quantitative risk factor for ectasia. The objective of this study was to assess flap thickness and calculate percentage tissue altered to check if unexpectedly thicker flaps and higher percentage tissue altered could pose as risk factors of ectasia. Four subjects (eight eyes) were submitted to mechanical LASIK in 2009 and 2010. Pre and postoperative clinical and tomographic data were reviewed. Mean preoperative estimated percentage tissue altered was 39.18±1.31%, which was borderline for increased ectasia risk when considering the limit of 40%. However, when considering the postoperatively measured flap thickness, the actual mean percentage tissue altered turned out to be 45.17 ± 4.13%, which was significantly higher than predicted preoperatively (p=0.002). Unexpectedly higher postoperative percentage tissue altered may be responsible for corneal ectasia after mechanical LASIK.

Copyright of Arquivos Brasileiros de Oftalmologia is the property of Arquivos Brasileiros de Oftalmologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

PurposeTo evaluate factors associated with the change in dry eye symptoms following laser vision correction.MethodsThis was a retrospective case series of 13,319 patients who underwent laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) between January 2013 and February 2016 and completed a preoperative and 3-month postoperative patient-reported outcome questionnaire.ResultsIn a multivariate linear regression model, women and contact lens wearers were associated with worse preoperative dry eye symptoms. Age was not significantly associated with preoperative dry eye symptoms. The change in dry eye symptoms preoperatively to postoperatively was affected by gender, procedure type, and preoperative dry eye symptoms. Patients who underwent PRK were more likely to report an increase in dry eye after 3 months (coefficient: 3.99, 95% confidence interval (CI): 1.64 to 4.82, P < .001) and patients with worse preoperative dry eye were more likely to have improvement in symptoms after surgery (coefficient: -0.93, 95% CI: -0.97 to -0.90, P < .001). More women reported an increased level of symptoms 3 months after surgery than men (coefficient: 1.76, 95% CI: 0.68 to 2.84, P = .001).ConclusionsPreoperative dry eye symptoms, female gender, and procedure type had a significant effect on preoperative to postoperative change in dry eye symptoms after laser vision correction. Age was not associated with dry eye symptoms in this population. [J Refract Surg. 2019;35(3):161-168.].

Objective: The purpose of this study was to develop and apply an online questionnaire to assess knowledge in Refractive Surgery in the analyzed population. Methods: An online questionnaire was applied to a population composed of 840 volunteer participants over 18 years of age. Results: The mean age of population was 37.85 years, of whom 60.1% were female. 20.95% of the participants reported having undergone previous eye surgery, 73.86% of which had a refractive objective. Among these, 73.08% were satisfied / very satisfied with the result. The most important criterion when choosing a refractive surgeon was the indication by a friend who underwent the procedure (43.81%). It is noteworthy that the participants who underwent refractive surgery disagreed more than the other people that “the surgery is a simple and risk-free procedure” (p = 0.0045) and that “the main objective of the surgery is to “zero” the diopter” (p = 0.0252). Conclusion: It is essential to improve population’s preoperative knowledge about Refractive Surgery, as well as continuing education for ophthalmologists. Therefore, this study encourages the development of new education tools with clear and easily accessible information, which should be informative, and not convincing. [ABSTRACT FROM AUTHOR]

Femtolasik is one of the most used techniques in refractive surgery due to good refractive results, predictability, reproducibility, and safety, achieving excellent results and a high degree of satisfaction. Although the complication rates are small, it is worth noting that there may be intercurrences. The objective of this work is to report a case of complication in the dissection of the lamella of laser in situ keratomileusis (Lasik) with Femtosecond laser, and subsequent lamella tear. Excimer Laser was applied with mitomycin 0.02% and re-approached with wavefront guided surgery, evolving with good final visual quality. [ABSTRACT FROM AUTHOR]

LASIK is a refractive surgical procedure in which a corneal flap is created to expose the corneal stromal bed. Preoperative estimation of corneal flap thickness is necessary to calculate the percentage tissue altered in LASIK, an important quantitative risk factor for ectasia. The objective of this study was to assess flap thickness and calculate percentage tissue altered to check if unexpectedly thicker flaps and higher percentage tissue altered could pose as risk factors of ectasia. Four subjects (eight eyes) were submitted to mechanical LASIK in 2009 and 2010. Pre and postoperative clinical and tomographic data were reviewed. Mean preoperative estimated percentage tissue altered was 39.18±1.31%, which was borderline for increased ectasia risk when considering the limit of 40%. However, when considering the postoperatively measured flap thickness, the actual mean percentage tissue altered turned out to be 45.17 ± 4.13%, which was significantly higher than predicted preoperatively (p=0.002). Unexpectedly higher postoperative percentage tissue altered may be responsible for corneal ectasia after mechanical LASIK. [ABSTRACT FROM AUTHOR]

Copyright of Arquivos Brasileiros de Oftalmologia is the property of Arquivos Brasileiros de Oftalmologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ImportancePatient-reported outcomes should be collected using validated questionnaires prior to and following laser in situ keratomileusis (LASIK) surgery.ObjectiveTo report the frequency of patient-reported visual symptoms, dry eye symptoms, satisfaction with vision, and satisfaction with LASIK surgery in the Patient-Reported Outcomes With LASIK (PROWL) studies.Design, setting, and participantsThe PROWL-1 and PROWL-2 studies were prospective, observational studies conducted from September 13, 2011, to June 27, 2014. The PROWL-1 study was a single-military center study of 262 active-duty Navy personnel 21 to 52 years of age. The PROWL-2 study was a study of 312 civilians 21 to 57 years of age conducted at 5 private practice and academic centers. The LASIK surgery and the postoperative care were performed based on the usual practice and clinical judgment at the site. Participants completed a self-administered, web-based questionnaire, preoperatively and postoperatively at 1 and 3 months (the PROWL-1 and -2 studies) and at 6 months (the PROWL-2 study).ExposuresParticipants underwent LASIK surgery for myopia, hyperopia, and/or astigmatism.Main outcomes and measuresVisual symptoms (double images, glare, halos, and/or starbursts), dry eye symptoms, participant satisfaction (with vision and LASIK surgery), and clinical measures (visual acuity, refractive error, and slitlamp and posterior segment eye examination findings) were assessed preoperatively and at 1, 3, and 6 months postoperatively.ResultsA total of 262 participants were enrolled in the PROWL-1 study (mean [SD] age, 29.1 [6.1] years), and a total of 312 participants were enrolled in the PROWL-2 study (mean [SD] age, 31.5 [7.3] years). Visual symptoms and dissatisfaction with vision were common preoperatively. Overall, the prevalence of visual symptoms and dry eye symptoms decreased, although a substantial percentage of participants reported new visual symptoms after surgery (43% [95% CI, 31%-55%] from the PROWL-1 study and 46% [95% CI, 33%-58%] from the PROWL-2 study at 3 months). The percentages of participants in the PROWL-1 study with normal Ocular Surface Disease Index scores were 55% (95% CI, 48%-61%) at baseline, 66% (95% CI, 59%-72%) at 3 months, and 73% (95% CI, 67%-79%) at 6 months. The percentages of participants in the PROWL-2 study with normal Ocular Surface Disease Index scores were 44% (95% CI, 38%-50%) at baseline and 65% (95% CI, 59%-71%) at 3 months. Of those participants who had normal scores at baseline in both the PROWL-1 and -2 studies, about 28% (95% CI, 19%-37%) had mild, moderate, or severe dry eye symptoms at 3 months. While most participants were satisfied, the rates of dissatisfaction with vision ranged from 1% (95% CI, 0%-4%) to 4% (95% CI, 2%-7%), and the rates of dissatisfaction with surgery ranged from 1% (95% CI, 0%-4%) to 2% (95% CI, 1%-5%).Conclusions and relevanceThe systematic administration of a questionnaire to patients who have undergone LASIK surgery is a new approach to assess symptoms and satisfaction. Our findings support the need for adequate counseling about the possibility of developing new symptoms after LASIK surgery.

ImportancePatient-reported outcome (PRO) measures for laser in situ keratomileusis (LASIK) are needed.ObjectiveTo develop PRO measures to assess satisfaction, eye-related symptoms, and their effect on functioning and well-being following LASIK based on patient and expert input.Design, setting, and participantsThe Patient-Reported Outcomes With LASIK (PROWL) studies were prospective observational studies of patients undergoing LASIK surgery for myopia, hyperopia, or astigmatism. PROWL-1 was a single-center study of active-duty US Navy personnel and PROWL-2 was a 5-center study of civilians. PROWL-1 enrolled 262 active-duty service personnel and PROWL-2 enrolled 312 civilians 21 years or older who spoke English; 241 individuals in PROWL-1 and 280 in PROWL-2 completed a baseline questionnaire before surgery. The analytic sample included those also completing 1 or more follow-up questionnaires: 240 (99.6%) of those in PROWL-1 and 271 (94.4%) of those in PROWL-2. Questionnaires were self-administered through the internet preoperatively and at 1 and 3 months postoperatively in both studies and at 6 months postoperatively in PROWL-1. PROWL-1 began in August 2011 and was completed May 30, 2014; PROWL-2 began in July 2012 and was completed June 27, 2014. Data were analyzed from June 28, 2014, to October 24, 2016.Main outcomes and measuresScales assessing visual symptoms (double images, glare, halos, and starbursts), dry eye symptoms, satisfaction with vision, and satisfaction with LASIK surgery. Items from the National Eye Institute (NEI) Refractive Error Quality of Life Instrument (NEI-RQL-42), NEI Visual Function Questionnaire (NEI-VFQ), and the Ocular Surface Disease Index (OSDI) were included. All scales are scored on a 0 to 100 possible range. Construct validity and responsiveness to change were evaluated (comparing scores before and after surgery).ResultsThe median age of the 240-person PROWL-1 analytic sample was 27 years (range, 21-52 years); 49 were women (20.4%). The median age of the 271-person PROWL-2 analytic sample was 30 years (range, 21-57 years); 147 were women (54.2%). Internal consistency reliabilities for the 4 visual symptom scales ranged from 0.96 to 0.98 in PROWL-1 and from 0.95 to 0.97 in PROWL-2. The median (interquartile range) test-retest intraclass correlation was 0.69 (0.57-0.79) and 0.76 (0.68-0.84) in PROWL-1 and PROWL-2, respectively. Product-moment correlations of satisfaction with surgery with visual symptom scales at follow-up evaluations ranged from r = 0.24 to r = 0.49. Measures improved from baseline to follow-up, with effect sizes of 0.14 to 1.98, but scores on the NEI-RQL-42 glare scale worsened at the 1-month follow-up. Hours of work did not change significantly from baseline to 1-month follow-up, with the mean number (mean [SD] difference) in PROWL-1 of 41.7 vs 40.9 hours (-0.8 [18.7]) and in PROWL-2 of 38.8 vs 38.2 hours (-0.6 [17.1]).Conclusions and relevanceThe results of these studies support the reliability and validity of visual symptom scales to evaluate the effects of LASIK surgery in future studies.

Purpose: To investigate patterns of short- and long-term variations in corneal epithelial thickness (CET) after myopic laser in situ keratomileusis (LASIK) using anterior segment optical coherence tomography (AS-OCT) combined with Placido disk-based topography. Methods: In this retrospective study, 36 subjects (72 eyes) who underwent LASIK myopic surgery and 53 healthy subjects (106 eyes) who served as controls were enrolled. AS-OCT (MS-39) was performed in all patients before, 1 day, 1 month, and 6 months after surgery. Statistical analysis was performed to analyze CET changes over time after LASIK and to detect patterns of definitive CET remodeling compared to healthy subjects. Multivariate analysis was performed to look for possible predictors of final CET. Results: There was no statistically significant difference between groups in terms of demographic and anterior segment parameters (all P > 0.05). After LASIK, all sectors and rings got thicker over time (1.62–8.32 μm; P < 0.01). Except for the central sector, all areas achieved the thickest CET value one day after surgery with a progressive epithelial thinning between 1 and 6 months of follow-up. Changes on CET occurred independently of the grade of myopia before LASIK or final refraction (P > 0.05). None of the clinical variables studied, including diopters corrected, were found to be correlated with final CET (P > 0.05). Conclusion: Independent of anterior segment parameters and diopters corrected, CET becomes thicker after LASIK surgery. Central and inner ring sectors thicken more than those more peripheral. CET remodeling after myopic LASIK should be taken into consideration when planning refractive surgery.

Transepithelial photorefractive keratectomy (Trans-PRK), laser-assisted in situ keratomileusis (LASIK), and small incision lenticule extraction (SMILE) are three mainstay refractive surgeries worldwide. The applicability, efficacy, safety, and predictability of these different techniques are quite similar. Trans-PRK has the strongest biostability, earliest return to normal corneal sensitivity but the longest recovery time, most uncomfortable postoperative experience, and possibility of corneal haze. LASIK possesses the fastest visual rehabilitation but the slowest corneal nerve reinnervation, and flap displacement is possibly lifelong. SMILE incurs no flap-related complications and has intermediate vision recovery time and biomechanics compared with Trans-PRK and LASIK. However, it lacks the cyclotorsion-compensation system, eye-tracking system, and customized treatment profile for high astigmatism or irregular corneal surface. This review aims to introduce the mechanisms, pros, and cons of these three types of refractive surgery. With full understanding, practitioners could advise patients on the most suitable treatment of choice. [ABSTRACT FROM AUTHOR]

Pterygium is one of the diseases that most affect the ocular surface, especially in regions close to the equator. It mainly affects young adults and can cause symptoms, as well as aesthetic and optical impairment. We report a case of pterygium excision classified by grade II corneal extension and Tan grade 2 vascularization with previous laser in situ keratomileusis (LASIK) surgery, using a new technique, the Moscovici technique, which is based on dissection with an air bubble to separate easier and faster the conjunctival epithelium from the deep stroma and the Tenon, obtaining thinner grafts. [ABSTRACT FROM AUTHOR]

Purpose: To investigate patterns of short- and long-term variations in corneal epithelial thickness (CET) after myopic laser in situ keratomileusis (LASIK) using anterior segment optical coherence tomography (AS-OCT) combined with Placido disk-based topography.Methods: In this retrospective study, 36 subjects (72 eyes) who underwent LASIK myopic surgery and 53 healthy subjects (106 eyes) who served as controls were enrolled. AS-OCT (MS-39) was performed in all patients before, 1 day, 1 month, and 6 months after surgery. Statistical analysis was performed to analyze CET changes over time after LASIK and to detect patterns of definitive CET remodeling compared to healthy subjects. Multivariate analysis was performed to look for possible predictors of final CET.Results: There was no statistically significant difference between groups in terms of demographic and anterior segment parameters (all P > 0.05). After LASIK, all sectors and rings got thicker over time (1.62-8.32 μm; P < 0.01). Except for the central sector, all areas achieved the thickest CET value one day after surgery with a progressive epithelial thinning between 1 and 6 months of follow-up. Changes on CET occurred independently of the grade of myopia before LASIK or final refraction (P > 0.05). None of the clinical variables studied, including diopters corrected, were found to be correlated with final CET (P > 0.05).Conclusion: Independent of anterior segment parameters and diopters corrected, CET becomes thicker after LASIK surgery. Central and inner ring sectors thicken more than those more peripheral. CET remodeling after myopic LASIK should be taken into consideration when planning refractive surgery. [ABSTRACT FROM AUTHOR]

Copyright of Türkiye Klinikleri Journal of Ophthalmology is the property of Turkiye Klinikleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ObjectiveTo determine whether procedure room temperature or humidity during LASIK affect refractive outcomes in a large patient sample.DesignRetrospective cohort study.ParticipantsA total of 202 394 eyes of 105 712 patients aged 18 to 75 years who underwent LASIK at an Optical Express, Inc., location in their United Kingdom and Ireland centers from January 1, 2008, to June 30, 2011, who met inclusion criteria.MethodsPatient age, gender, flap creation technique, pre- and 1-month post-LASIK manifest refraction, and ambient temperature and humidity during LASIK were recorded. Effect size determination and univariate and multivariate analyses were performed to characterize the relationships between LASIK procedure room temperature and humidity and postoperative refractive outcome.Main outcome measuresOne month post-LASIK manifest refraction.ResultsNo clinically significant effect of procedure room temperature or humidity was found on LASIK refractive outcomes. When considering all eyes in our population, an increase of 1°C during LASIK was associated with a 0.003 diopter (D) more hyperopic refraction 1 month postoperatively, and an increase in 1% humidity was associated with a 0.0004 more myopic refraction. These effect sizes were the same or similar when considering only myopic eyes, only hyperopic eyes, and subgroups of eyes stratified by age and preoperative refractive error.ConclusionsNeither procedure room temperature nor humidity during LASIK were found to have a clinically significant relationship with postoperative manifest refraction in our population.

Copyright of Arquivos Brasileiros de Oftalmologia is the property of Arquivos Brasileiros de Oftalmologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

AIM: To investigate the difference in kappa angle between sitting and supine positions during laser-assisted in situ keratomileusis (LASIK). METHODS: A retrospective study was performed on 395 eyes from 215 patients with myopia that received LASIK. Low, moderate, and high myopia groups were assigned according to diopters. The horizontal and vertical components of kappa angle in sitting position were measured before the operation, and in supine position during the operation. The data from the two positions were compared and the relationship between kappa angle and diopters were analyzed. RESULTS: Two hundred and twenty-three eyes (56.5%) in sitting position and 343 eyes (86.8%) in supine position had positive kappa angles. There were no significant differences in horizontal and vertical components of kappa angle in the sitting position or horizontal components of kappa angle in the supine position between the three groups (P>0.05). A significant difference in the vertical components of kappa angle in the supine position was seen in the three groups (P

Background/Aim. Enlargement of optical zone (OZ) diameter during laser in situ keratomileusis (LASIK) correction of myopia postoperatively improves the optical outcome, however, it also leads to the increased stroma tissue consumption - progressive corneal thinning. The aim of this investigation was to present the possibility of safe OZ enlargement without impairing the structural stability of the cornea, while obtaining an improved optical outcome with LASIK treatment of shortsightedness. Methods. Preoperative assessment of the cornea structure and prediction of the ablated stroma tissue consumption was conducted in 37 patients (74 eyes) treated for shortsightedness by means of the LASIK method. With the eyes that, according to their cornea structure, had the capacity for OZ diameter enlargement of 0.5 mm, LASIK treatment was performed within the wider OZ diameter of 7.0 mm compared to the standard 6.5 mm. The following two groups were formed, depending on the diameter of the utilized OZ: the group I (the eyes treated with the OZ 6.5 mm, n = 37) and the group II (the eyes treated with the OZ 7.0 mm, n = 37). Results. No significant difference in the observed structural parameters of the cornea was detected between the groups of patients treated with different OZ diameters. The values of all the parameters were significantly bellow the threshold values for the development of postoperative ectasia. Conclusion. Diameter enlargement of the treated OZ, if there is a preoperative cornea capacity for such enlargement, will not impair the postoperative stability of the cornea structure, and will significantly improve the optical outcome.

Astigmatism is corrected by either by toric lenses or surgical intervention including laser refractive surgery. Photorefractive keratectomy (PRK) is performed with the excimer laser which can accurately ablate corneal tissue to an exact depth with minimal disruption of surrounding tissue, it is done by removing the epithelial layer up to Bowman layer which then ablate with anterior stroma. Laser in situ keratomileusis (LASIK) is also performed with the excimer laser, but with creation a flap involving the stroma. This study aimed to compare the differences in visual outcome after 6 months between PRK and LASIK in treatment of astigmatism. It is a retrospective study in which 222 eyes of 115 patients (some of them had only astigmatism in one eye) who underwent laser refractive correction in Al-Hakeem General Hospital in Annajaf city to correct their astigmatismic refractive error were included in the study, 152 of astigmtismic eyes were corrected by LASIK (82 of female eyes and 70 of male eyes), 67 of astigmatismic eyes were corrected by PRK ( 35 of female eyes and 32 of male eyes). Patients were grouped into six groups according to their refractive error: G1: less than 1.0 dioptre, G2: 1.0-1.9 dioptres, G3: 2.0-2.9dioptres, G4: 3.0-3.9 dioptres, G5: 4.0-4.9dioptres and G6: 5.0-14.0 dioptres. The outcome of visual acuity was followed-up by autorefraction six months postoperatively and were grouped into five groups according to their visual outcome: a:emmetropia, b:no correction, c:undercorrection, d: increase the refractive error, e: overcorrection. The results shows that in those with astigmatism between 0.25-0.9 dioptre, no statistically significant association was found between outcome and type of operation (P=0.66). In those with astigmatism between 1.0-1.9 dioptres, statistically significant association was found between outcome and type of operation (p=0.023). In those with astigmatism between 2.0-2.9 dioptres, statistically significant association was found between outcome and type of operation (P=0.0009). In those with astigmatism between 3.0-3.9 dioptres, statistically significant association was found between outcome and type of operation (P=0.001). In those with astigmatism between 4.0-4.9 dioptres, no statistically significant association was found between outcome and type of operation (P=0.113). In those with astigmatism between 5.0-14.0 dioptres, no statistically significant association was found between outcome and type of operation (P=0.92). In conclusion, there is no statistical significant difference after 6 months of correction of astigmatism wither by LASIK or PRK at different levels of refractive error.

Copyright of Arquivos Brasileiros de Oftalmologia is the property of Arquivos Brasileiros de Oftalmologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

AIM: To assess the changes on higher-order aberrations(HOA)after three different corneal refractive surgeries, including laser-assisted in situ keratomileusis(LASIK), femtosecond LASIK(FS-LASIK)and femtosecond lenticule extraction(FLEx). METHODS: One hundred and twenty-five patients(245 eyes)from June 2014 to March 2015 in refractive surgery center of our hospital were recruited. There were 38 patients(74 eyes)underwent LASIK, 42 patients(83 eyes)underwent FS-LASIK, and 45 patients(88 eyes)underwent FLEx. The higher-order aberrations were measured preoperatively, at 1mo after surgeries with iTrace. The repeated measure of ANOVA was used to analyze the changes on higher-order aberrations among the groups. RESULTS: Compared to the preoperative corneal higher-order aberrations, vertical coma aberration, horizontal coma aberration and spherical aberration, there were significantly differences in the three groups postoperatively(P=0.002, P>0.05). But it showed difference on vertical coma aberration(F=3.943,P=0.021). By multiple comparisons, there were statistical significance on vertical coma aberration between FLEx group and the other two.CONCLUSION: The postoperative corneal higher-order aberrations all in creased in three groups. Due to the large incision in FLEx, the corneal aberration is still increased after surgeries. And the FLEx does not show a certain advantage yet.

Introduction:Corneal ectasia is a group of related diseases characterized by progressive corneal steepening and thinning. It includes keratoconus, pellucid marginal degeneration (PMD), and post-laser ectasia. Traditionally, treatment of these conditions has involved visual rehabilitation with spectacles or contact lenses, with often eventual need for corneal transplantation. Areas covered:This review focuses on refractive surgery treatment options available for ectasia including collagen cross-linking (CXL), excimer laser, intrastromal corneal ring segments (ICRSs), and intraocular lenses (IOLs). A comprehensive literature review using OVID Medline and Embase was undertaken. Expert commentary:CXL has shown promising short- and long-term results in stabilizing patients with corneal ectasia. When combined with excimer laser using topography- or wavefront-guided photorefractive keratectomy (PRK), many patients are able to gain significant improvements in visual acuity and contact lens tolerance, which may delay or prevent altogether the need for corneal transplantation. Other treatments such as ICRSs, phakic IOLs, and TORIC IOLs may be beneficial in select cases for visual rehabilitation. [ABSTRACT FROM PUBLISHER]

AIM: To observe the predictability of corneal flap creation with the VisuMax femtosecond laser and preliminarily analyze the factors correlated to the thickness and diameter of the flap. METHODS: This retrospective case series study included 300 eyes of 150 consecutive patients. The eyes were assigned to two groups according to intended flap thickness, 100μm(204 eyes)and 110μm(96 eyes), which created with the VisuMax femtosecond laser. Intended flap diameters were 7.9mm and 8.3mm. Difference analysis of flap diameter and intended diameter as well as flap thickness and intended thickness were made. The data were analyzed with SPSS to sum up a multiple stepwise regression formula that could express their quantitative relationship. RESULTS: The 100μm flap group had an average flap thickness of 103.11±4.07μm, while for the 110μm group the average flap thickness was 113.35±5.71μm. The difference between right and left eyes was not statistically significant(t100μm =-0.901, t 110μm=-0.490; P>0.05). Corneal flap thickness was not related to flap diameter(r=0.003, 0.018; P>0.05), preoperative patient age(r=0.022, 0.050; P>0.05), corneal thickness(r=0.051, 0.101; P>0.05), keratometric value K(r=-0.048, -0.136; P>0.05)or intraocular pressure(r=-0.113, 0.047; P>0.05). Preoperative corneal keratometric value K was positively correlated with corneal flap diameter(r=0.359, 0.532; P=0.01, 0.007CONCLUSION:The LASIK flap creation with the VisuMax femtosecond laser has relatively good predictability. There is no influencing factor for flap thickness.

Background/Aim. Immune response and consequent inflammatory process which originate on ocular surface after a trauma are mediated by cytokines. Photoablation of corneal stroma performed by excimer laser causes surgically induced trauma. Interleukin-6 (IL-6) is mostly known as a proinflammatory cytokine. However, it also has regenerative and anti-inflammatory effects. It is supposed that this cytokine is likely to play a significant role in the process of corneal wound healing response after photoablation of stroma carried out by laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) methods. The aim of this study was to determine and compare the levels of IL-6 in tears before and after treatment with LASIK and PRK methods. Methods. The study included 68 shortsighted eyes up to -3.0 diopter sphere, i.e. 198 samples of tears (per three samples taken from each of the eyes), divided into two groups according to the kind of excimer laser intervention performed: the group 1 -- eyes treated by LASIK method (n = 31), and the group 2 -- eyes treated by the PRK method (n = 37). The samples of tears were taken from each eye at the following time points: before excimer laser treatment (0 h, the control group), 1 h after the treatment (1 h) and 24 h after the treatment (24 h). The patients did not use anti-inflammatory therapy 24 h after the intervention. Tear samples were collected using microsurgical sponge. Level of IL-6 in tear fluid was determined by the flow cytometry method, applying a commercial test kit which allowed cytokine detection from a small sample volume. Results. The values of IL-6 were detectable in 16% of samples before LASIK treatment and in 30% of samples before PRK treatment. One h after the treatment IL-6 was detectable in 29% of samples for the LASIK group and 43% of samples for the PRK group, and 24 h after the treatment it was detectable in 19% of samples for the LASIK group and in 57% of samples for the PRK group. When we analyzed the dynamics of IL-6 production in particular groups, we noticed that both in the LASIK and PRK group the number of samples with increased values of IL-6 after 1 h, and after 24 h, was considerably larger than the number of samples with decreased values of IL-6 after the intervention. Analyzing the dynamics of IL-6 concentration changes in the 1 h samples vs 24 h samples there was a statistically significant increase in the number of samples with IL-6 concentration decline in the LASIK group, while at the same time no considerable changes occurred in the PRK group. Comparing average IL-6 values between the two treatment groups in all tear samples at 0 h, 1 h and 24 h after intervention a significantly higher level in the PRK group 24 h after procedure (p = 0.0031) was detected. Conclusion. IL-6 level in tears increases 1 h and 24 h after LASIK and PRK treatments. This increment is significantly larger 24 h after the treatment with the PRK method than with the LASIK method. Changes of IL-6 production levels in tears after excimer laser treatment indicate that this cytokine takes part in the corneal recovery process after stromal photoablation. [ABSTRACT FROM AUTHOR]

Objective To investigate the relationship between eye injury and laser in-situ keratomileusis (LASIK) surgery in military personnel. Methods This retrospective study collected the data from 27 evacuation hospitals of Chinese army. All medical records of eye injuries in military personnel admitted to the 27 hospitals between January 2006 and December 2010 were reviewed. Patients’ detailed information was analyzed, including the injury time, place, type, cause, as well as examination, treatment and outcome. Results There were 72 eye-injured patients who had been treated by LASIK before. The incidence was rising year by year. Among them, 69 patients were diagnosed with mechanical ocular injury and 3 with non-mechanical ocular injury; 29 patients had traumatic flap-related complications and 21 patients need surgery. There was statistical difference when compared with those having no refractive surgery history. Visual acuity recovered well at discharge. Conclusion There is a high risk of potential traumatic flap problems after LASIK and it is not recommended in army service. [ABSTRACT FROM AUTHOR]

Introduction: To compare the efficacy and cost-effectiveness of Femtosecond laser versus mechanical Microkeratome corneal flap creation in correction of refractive errors. Methods: In this review, a comprehensive search of Medline, SCOPUS, Cochrane, TRIP database, supplemented by HTA and economic databases was performed. We searched for randomized controlled trials (RCTs) of Femtosecond laser which included mechanical Microkeratome in other arm. The quality of the retrieved studies was appraised by two independent reviewers and appropriate articles were finalized. Result: A total of 1142 articles were identified, of which, 1059 were excluded after review of the titles and abstracts and 83 articles remained. Systematic reviews and RCTs were evaluated through CASP international worksheet. Eventually, 61 titles were excluded, leaving 22 articles to be reviewed. Safety: There was no individual evidence to cover all safety components about Femtosecond laser, but in summary, this modality seems a safe method for corneal flap creation. Effectiveness: No statistically significant difference was shown in visual acuity and refractive errors. The important secondary end point of this review was diffuse Lamellar keratitis in 17% of the Femtosecond group versus 5% in mechanical Microkeratome. Inflammation was low-grade and improved during the first 3 months of follow-up period with a low dose medication without corneal scarring. The two groups was comparable in all clinical outcomes including Unorrected Visual Acuity (UCVA), Best Special Corrected Visual Acuity (BSCVA), manifest refraction, wave front aberrometry, Schirmer test, and Tear Break up time (TBUT). Cost Analysis: Results showed that marginal cost incurred due to Femtosecond technology adoption may vary from 27 to 117 € (resulted from sensitivity analysis). It is clear that additional cost may be a small proportion of LASIK procedure total cost. Conclusion: Although Femtosecond flap creation is a modern method with a good quality of corneal flap, but, there is no high-quality evidence to show superiority of Femtosecond laser in clinical outcomes. Although the efficacy and cost of the systems is almost equal, traditional method still remains as the standard approach. [ABSTRACT FROM AUTHOR]

DSAEK (Descemet stripping automated endothelial keratoplasty) is one of the options for corneal endothelium disease, which in some patients can result in a residual hyperopia after the procedure. Usually 6 to 12 months after corneal transplantation refraction is already stable. This report describes a therapeutic option used in a 54 years old patient with Fuchs' endothelial dystrophy submitted to cataract and corneal transplant that resulted in residual hyperopia, three years after the procedure the best corrected vision was 20/20 with a refraction of +3.25 -1.00 (5 °) treated with Hyperopic - LASIK (Laser-assisted In Situ Keratomileusis) with satisfactory visual result. [ABSTRACT FROM AUTHOR]

Background/Aim. Laser in situ keratamileusis (LASIK) is the most commonly used refractive surgical method worldwide. The aim of this study was to examine the effectiveness and safety of LASIK in the correction of myopia and hyperopia. Methods. The study included myopic and hyperopic eyes with preoperative best corrected visual acuity (BCVA) = 1 (20/20), of the total number of 322 divided into 2 groups -- 1) myopic eyes (n = 241) which were divided into 4 subgroups according to the myopia strength: a) = -1.75 D (n = 23), b) from -2 to -3.75 D (n = 81), c) from -4 to -6.75 D (n = 113), d) = -7 D (n = 24); 2) hyperopic eyes (n = 81) which were divided into 3 subgroups according to the hyperopia strength: a) = +1.75D (n = 10), b) from +2 to +3.75 D (n = 46), c) = +4 D (n = 25). Myopic and hyperopic eyes with preoperative BCVA = 0.9 (eyes with ambliopia) were excluded from the study, as well as eyes with astigmatism > 1.5 D. To assess the effectiveness of LASIK we examined the percentage of eyes in the mentioned subgroups, which derived uncorrected visual acuity (UCVA) 6 month after the intervention to the following: a) UCVA = 1 (20/20) and b) UCVA = 0.5 (20/40). To assess the safety of LASIK we examined the frequency of intraoperative and postoperative complications. A prospective study was performed in a 6-months follow-up period. Results. Refractive spherical equivalent (RSE) of myopic eyes was in the range from -0.75 D to -12 D. In the first subgroup preoperative mean value of RSE with standard deviation (mean RSE ± SD) was -1.39 ± 0.36 D, and 6 months after the LASIK 100% of the eyes had UCVA = 20/20. In the second subgroup preoperative mean RSE ± SD was -2.85 ± 0.50 D, and 6 months after LASIK 93% of the eyes had UCVA = 20/20, but 100% of the eyes had UCVA = 20/40. In the third subgroup preoperative mean RSE ± SD was -5.03 ± 0.75 D, and 6 months after the LASIK 90% of the eyes had UCVA = 20/20, but 100% of the eyes had UCVA = 20/40. In the fourth subgroup preoperative mean RSE ± SD was -7.68 ± 1.03 D, and 6 months after the LASIK 96% of the eyes had UCVA = 20/20, but 100% of eyes had UCVA = 20/40. Refractive spherical equivalent of hyperopic eyes was in the range from +1 D to +6 D. In the first subgroup preoperative mean RSE ± SD was +1.50 ± 0.30 D, and 6 months after the LASIK 90% of the eyes had UCVA = 20/20, but 100% of the eyes had UCVA = 20/40. In the second subgroup preoperative mean RSE ± SD was +2.65 ± 0.46 D, and 6 months after the LASIK 87% of the eyes had UCVA = 20/20, but 96% of the eyes had UCVA = 20/40. In the third subgroup preoperative mean RSE ± SD was +4.62 ± 0.68 D, and 6 months after the LASIK 64% of the eyes had UCVA = 20/20, but 100% of the eyes had UCVA = 20/40. In our study intraoperative complications appeared in 6 eyes (1.86%): thin flap in 2 eyes (0.62%) and epithelial defects in 4 eyes (1.24%), yet postoperative complications appeared in 10 eyes (3.10%): flap folds in 2 eyes (0.62%), epithelial ingrowth in 4 eyes (1.24%) and regression in 4 eyes (1.24%). Conclusion. LASIK is effective and safe refractive surgical method for correcting myopia up to -12 D and hyperopia up to +6 D. [ABSTRACT FROM AUTHOR]

Objective To evaluate human corneas after laser-assisted in situ keratomileusis at different postoperative intervals. Methods Thirty-eight postmortem corneas from 20 patients with postoperative intervals from 2 months to 6.5 years after laser-assisted in situ keratomileusis surgery were collected from eye banks. The corneas were trisected and processed for conventional histologic analysis, transmission electron microscopy, and immunofluorescence. Results Light microscopy and transmission electron microscopy showed focal undulations in Bowman layer, focal epithelial hypertrophic modifications, and a variably thick (range, 0.4-16.4-μm) lamellar stromal interface scar in all specimens. The flap wound margin, which was adjacent to the epithelium, healed by producing an approximately 8-μm-thick hypercellular fibrotic stromal scar, whereas the central and paracentral wound regions healed differently because a thinner (approximately 5-μm) hypocellular primitive stromal scar was present in all the corneas examined. Immunofluorescence identified increased type 3 collagen and myofibroblasts in the hypercellular fibrotic scar regions and decreased or absent levels of all corneal stromal components other than type 1 collagen in the hypocellular primitive scar regions. Conclusions After laser-assisted in situ keratomileusis surgery, the keratocyte-mediated production of a variably thick lamellar corneal stromal scar occurs, resulting in 2 regional types of scarring. The hypercellular fibrotic scar at the wound margin is usually visible clinically and functions to hold the flap in place, while the more central hypocellular primitive scar is not visible clinically and allows easy lifting of the flap postoperatively. [ABSTRACT FROM AUTHOR]

The authors report the case of a patient who developed cystoid macular edema after surgery for myopia by LASIK method. She was treated with intravitreal injections of ranibizumab and presented satisfactory visual result. [ABSTRACT FROM AUTHOR]

Laser refractive surgery is one of the most commonly performed procedures worldwide. In laser refractive surgery, Femtosecond Laser in Situ Keratomileusis and Refractive Lenticule Extraction have emerged as promising alternatives to microkeratome Laser in Situ Keratomileusis and Photorefractive Keratectomy. Following laser refractive surgery, the corneal nerves, epithelial and stromal cells release neuromediators, including neurotrophins, neuropeptides and neurotransmitters. Notably, nerve growth factor, substance P, calcitonin gene-related peptide and various cytokines are important mediators of neurogenic inflammation and corneal nerve regeneration. Alterations in neuromediator profiles and ocular surface parameters following laser refractive surgery are attributed to the surgical techniques and the severity of tissue insult induced. In this review, we will discuss the (1) Functions of neuromediators and their physiological and clinical significance; (2) Changes in the neuromediators following various laser refractive surgeries; (3) Correlation between neuromediators, ocular surface health and corneal nerve status; and (4) Future directions, including the use of neuromediators as potential biomarkers for ocular surface health following laser refractive surgery, and as adjuncts to aid in corneal regeneration after laser refractive surgery., Competing Interests: None

A laser-assisted in situ keratomileusis posterior ablation platform was developed to improve the ease and quality of the undersurface ablation of the flap technique. This ergonomic instrument combines a fixation ring with a platform that provides a physiologically spherical and smooth, low-reflective surface to extend the turned flap during the undersurface ablation of the flap retreatment. It was used successfully in 17 enhancement procedures when there was insufficient posterior stroma for additional treatment but adequate flap stroma. The result was improved globe stabilization and stromal smoothness during ablation. An efficacy index of 1 was achieved day 1 postoperatively in a greater percentage of eyes (88.2%) than without its use (29.4%; P = .001). The L-PAP appears to facilitate UAF procedures and prompt visual recovery. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor of "Archives of Ophthalmology" concerning an article on predictive value of slitlamp examinations in screening donor corneas for prior refractive surgery.

Presents a reply to a letter to the editor of "Archives of Ophthalmology" concerning an article on predictive value of slitlamp examinations in screening donor corneas for prior refractive surgery.