Laser-assisted In Situ Keratomileusis Surgery Research Articles

Comparison of early changes in tear film protein profiles after small incision lenticule extraction (SMILE) and femtosecond LASIK (FS-LASIK) surgery

BackgroundSmall incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (LASIK) are widely used surgical methods to correct myopia with comparable efficacy, predictability, and safety. We examined and compared the early changes of tear protein profiles after SMILE and FS-LASIK surgery in order to find possible differences in the initial corneal healing process.MethodsSMILE operations for 26 eyes were made with Visumax femtosecond laser. In FS-LASIK surgery for 30 eyes, the flaps were made with Ziemer FEMTO LDV Z6 femtosecond laser and stromal ablation with Wavelight EX500 excimer laser. Tear samples were collected preoperatively, and 1.5 h and 1 month postoperatively using glass microcapillary tubes. Tear protein identification and quantification were performed with sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS).ResultsImmediately (1.5 h) after we found differences in 89 proteins after SMILE and in 123 after FS-LASIK operation compared to preoperative protein levels. Of these differentially expressed proteins, 48 proteins were common for both surgery types. There were, however, quantitative differences between SMILE and FS-LASIK. Upregulated proteins were mostly connected to inflammatory response and migration of the cells connected to immune system. One month after the operation protein expressions levels were returned to baseline levels with both surgical methods.ConclusionsOur study showed that immediate changes in protein profiles after SMILE and FS-LASIK surgeries and differences between the methods are connected to inflammatory process, and the protein levels quickly return to the baseline within 1 month. The differences in protein profiles between the methods are probably associated with the different size of the epithelial wound induced.

Non-invasive assessment of the tear film after LASIK.

The aim of the study was to compare the assessment of the ocular surface using classic methods with the newly developed keratoscopy-based MYAH (Topcon EU, Visia Imaging, Japan) device after femtosecond laser-assisted in situ keratomileusis (LASIK). This cross-sectional and observational study analyzed 80 eyes of 40 patients. Tear film and ocular surface evaluation were performed at baseline, postoperative week 1, and month 1. Measurements obtained using the Schirmer I test and invasive tear-film breakup time (I-TBT) were compared with non-invasive evaluation of the tear break-up time (NI-TBT), tear meniscus height (TMH) and blink analysis obtained using the MYAH device. Findings were correlated with the Ocular Surface Disease Index (OSDI) questionnaire in all subjects. The study included 80 eyes of 40 consecutive patients (21 males and 19 females) with a mean age of 26.6 ± 5.9 years (18-40 years) and a mean spherical equivalent value of -3.64 D (-9.63 to -0.25 D). There was a significant decrease in Schirmer I test (19.21 ± 8.4 vs. 16.61 ± 9.1 vs. 14.69 ± 9.86, p= 0.02, respectively) and I-TBT values (8.59 ± 3.4 vs. 7.4 ± 3.25 vs. 6.17 ± 3.01, p=0.03 respectively). OSDI values showed a significant increase after LASIK (11.56 ± 6.3 vs. 17.24 ± 7.5 vs. 14.71 ± 9.6, p=0.03, respectively). 5% level NI-TBT was significantly lower at 1 week 6.75 and 1 month 7.45 than baseline 13.2 at follow-up (p=0.037). Ocular protection index (6.6 vs. 2.3 vs. 2.6, p=0.009, respectively) and blink/minutes (18 vs. 17 vs. 15, p=0.002, respectively) values showed a statistically significant decrease. Our data detected a weak correlation between I-TBT and noninvasive first TBT, 5% level TBT parameters at month 1 follow-up. This study also found no correlation between contact lens use, older age, female gender, and pre-operative refractive error with the noninvasive MYAH dry eye parameters. This study demonstrated the ability of the new keratoscopy-based MYAH device to detect changes in the short term after LASIK surgery.

Evaluación de las modificaciones biométricas del ojo durante la succión del LASIK

PurposeTo study the biometric modifications of the eyeball during suction in laser assisted in situ keratomileusis (LASIK). MethodsObservational and cross-sectional study. We studied 43 patients who underwent surgery for myopia and myopic astigmatism. Mean age was 38.3±11.5 years, and 19 were female (44.2%). Conventional LASIK surgery with a manual microkeratome was performed. Before and during the suction maneuvre the following parameters were measured using an 11 MHz biometric probe: aqueous depth (AQD), lens thickness (LT), vitreous cavity length (VCL) and axial length (AXL). Paired t-test was used to compare the biometric measurements before and during suction. ResultsThe mean spherical equivalent refractive error was −4.5±2.3 diopters. During suction, the AQD did not change significantly (p = 0.231). However, AXL and VCL increased by 0.12 mm and 0.22 mm respectively (p = 0.039 and <0.01) and LT decreased by 0.20 mm (p<0.01). AXL increased in 42% of the eyes and decreased in 16%, VCL increased in 70% of the eyes and decreased in 9%, and the LT was reduced in 67% of the eyes. ConclusionsSuction maneuvres during LASIK surgery produce changes of little magnitude in the eye globe, mainly a decrease in LT and an increase in VCL and AXL. Therefore, these modifications are expected to produce minimal anatomic alterations.

Assessment of the biometric modifications of the eye in LASIK during suction

PurposeTo study the biometric modifications of the eyeball during suction in Laser assisted in Situ Keratomileusis (LASIK). MethodsObservational and cross-sectional study. We studied 43 patients who underwent surgery for myopia and myopic astigmatism. Mean age was 38.3 ± 11.5 years, and 19 were female (44.2%). Conventional LASIK surgery with a manual microkeratome was performed. Before and during the suction maneuvre the following parameters were measured using an 11 Mhz biometric probe: aqueous depth (AQD), lens thickness (LT), vitreous cavity length (VCL) and axial length (AXL). Paired t-test was used to compare the biometric measurements before and during suction. ResultsThe mean spherical equivalent refractive error was −4.5 ± 2.3 diopters. During suction, the AQD did not change significantly (p = 0.231). However, AXL and VCL increased by 0.12 mm and 0.22 mm respectively (p = 0.039 and <0.01) and LT decreased by 0.20 mm (p < 0.01). AXL increased in 42% of the eyes and decreased in 16%, VCL increased in 70% of the eyes and decreased in 9%, and the LT was reduced in 67% of the eyes. ConclusionsSuction maneuvres during LASIK surgery produce changes of little magnitude in the eye globe, mainly a decrease in LT and an increase in VCL and AXL. Therefore, these modifications are expected to produce minimal anatomic alterations.

Evaluation of corneal flap thickness in relation to central corneal thickness after laser assisted in situ keratomileusis using two types of micro keratomes

Background: The most common refractive surgical surgery for the treatment of myopia, hyperopia, and astigmatism is laser assisted in situ keratomileusis (LASIK). A very important step in LASIK surgery is the formation of the flap. The corneal flap was made using a variety of microkeratomes. The purpose of this study was to compare the central corneal thickness following LASIK to the corneal thickness of the flap.Methods: This retrospective comparative study was performed on 200 eyeballs divided into four groups each of 50 eyeballs according to the type of microkeratome used for surgery; group 1 (M2 90), group 2 (M2 130), group 3 (SBK 90), group 4 (SBK 130). Cases were operated during the last seven years by ALCON WAVELIGHT EX500 unit (year of production: 2012).Results: Two hundred eyeballs of 100 patients were treated. Mean thickness of the flap of 103.3±9.54 mm, 126.05±17.07 mm, 120.9±14.4 mm, and 141.19±11.63 mm The SBK head created the thinnest flaps in the first cut utilising the SBK 90, SBK 130, M2 90, and M2 130 heads, respectively. The SBK 90 head produced the most exact and precise thickness of the flap, followed by the SBK 130 head, the M2 90 head, and the M2 130 head, as shown by the standard deviation and difference from the desired value.Conclusions: Of the 4 types, the SBK generally produced the thinnest and most accurate flaps.

Comparison of surgically induced astigmatic changes after cataract surgery in post-Laser in situ keratomileusis corneas versus virgin eyes.

Postoperative refraction in modern mi-croincision cataract surgery gained extra importance in patients with the previous laser-assisted in situ keratomileusis (LASIK) surgery. The surgically induced astigmatic changes in those eyes may differ not only in magnitude but also in direction compared to virgin corneas. This study aimed to compare the surgically induced astigmatic changes after microscopic cataract surgery between post-LASIK corneas and virgin eyes. Cases that underwent microincision cataract surgery in eyes with and without previous LASIK surgery were reviewed. The demographics, the axial length at cataract surgery, the central corneal thickness, spheric and cylindric values, keratometry readings, and postoperative posterior corneal astigmatism were retrospectively evaluated. A modified Alpins method was used for astigmatic vector analysis, and baseline astigmatism, surgically induced astigmatism, difference vector, flattening effect, and torque were assessed. A total of 42 eyes from 24 subjects was evaluated. Group I consisted of 14 eyes with the previous LASIK, and Group II included 28 eyes without any refractive surgery. Preoperative mean central corneal thickness in Group I was significantly thinner (p=0.012). There was no significant difference in baseline astigmatism between the groups regarding magnitude and power vectors. After microincision cataract surgery, there were no significant differences in mean spheric and cylindric values and mean keratometry readings (all p>0.05). However, surgically induced astigmatism and difference vector were significantly higher on J45 vector component in post-LASIK eyes and microincision cataract surgery steepening effect on post-LASIK corneas was significantly higher than those in virgin eyes (p=0.001, p=0.002 and p=0.018, respectively). Cataract surgery has steepened the corneas in both groups with a significantly higher steepening effect in post-LASIK eyes. Certainly, corneal topography cataract surgery is particularly helpful to provide more precise surgically induced astigmatism interpretations.

The Effect of Meibomian Gland Dysfunction on Laser-Assisted InSitu Keratomileusis in Asymptomatic Patients.

To evaluate the impact of asymptomatic meibomian gland dysfunction (MGD) on laser-assisted insitu keratomileusis (LASIK) outcomes and dry eye signs and symptoms. A retrospective analysis of patients who underwent LASIK surgery between July 2017 and February 2018 at Care Vision Refractive Clinic, Tel Aviv, Israel, was done. Patients were divided into those who had preoperative asymptomatic significant MGD (MGD group) and those who did not have preoperative significant MGD (control group). Outcomes were the postoperative presence of punctate epithelial erosions, dry eye symptoms, the number of postoperative visits as a measure of adverse events, visual acuity, spherical equivalent, safety index, efficacy index, and the type of refractive error (myopia or hyperopia). A total of 497 eyes were included in this study. Both groups had similar rates of punctate epithelial erosions, 30 (12.9%) patients vs. 39 patients (14.8%) (p = 0.31); postoperative complaints of dryness, 75 patients (32.3%) vs. 90 patients (34.2%) (p = 0.36); and postoperative number of visits, 3.15 ± 0.75 vs. 3.12 ± 0.54 (p = 0.59). Uncorrected visual acuity (logMAR) at 1month (0.026 ± 0.09 vs. 0.026 ± 0.17, p = 0.99) after surgery was similar in both groups. Mean spherical equivalent was 0.03 ± 0.17 and - 0.03 ± 0.18 (p = 0.99) in both groups. Safety index was 1.024 ± 0.06 in the clinically significant MGD group and 1.029 ± 0.07 in the control group (p = 0.45). Efficacy index was also similar in both groups (0.966 ± 0.155 and 0.979 ± 0.14, respectively, p = 0.31). No differences were found between patients with myopia and hyperopia. Patients with preoperative asymptomatic MGD have similar LASIK outcomes to patients without preoperative asymptomatic MGD. Accordingly, no preoperative MGD treatment or special caution is needed in these cases.

Lipidomics Analysis of the Tears in the Patients Receiving LASIK, FS-LASIK, or SBK Surgery.

Purpose: Tear film lipid layer (TFLL) plays a vital role in maintaining the tear film stability and, thus, the lipid composition of the tears could greatly affect the physiological function and biophysical integrity of the tear film. The objective of this study is to assess the tear lipid composition of the patients receiving laser-assisted in situ keratomileusis (LASIK), femtosecond LASIK (FS-LASIK), or sub-Bowman's keratomileusis (SBK) surgery preoperatively and postoperatively.Methods: Tear samples were collected from the left eye of the patient who receiving LASIK (n = 10), FS-LASIK (n = 10), or SBK (n = 10) surgery in week 0, week 1, week 4, and week 52. A rapid direct injection shotgun lipidomics workflow, MS/MSALL (<2 min/sample), was applied to examine the tear lipidome.Results: In week 52, the SBK group demonstrated a similar lipidome profile compared to week 0, while the FS-LASIK and LASIK groups shifted away from week 0. Two lipids, ganglioside (GD3) 27:4 and triacylglycerol (TAG) 59:3, were found to be associated with the lipidome changes preoperatively and postoperatively. No statistical significance was found in the overall lipid classes from the FS-LASIK group. The LASIK group showed significant alteration in the phospholipid and sphingolipid over time, while the SBK group demonstrated a significant difference in the (O-acyl)-ω-hydroxy fatty acid (OAHFA) and phospholipid.Conclusion: LASIK showed the greatest impact on the tear lipidome changes over time, while SBK demonstrated minimal impact among the three types of refractive surgeries after 1 year.

High-order aberration changes after femtosecond LASIK surgery in patients with high myopia.

To investigate the relationship between high-order aberration (HOA) changes and RCST/CT (residual corneal stroma thickness/corneal thickness) after femtosecond LASIK surgery. A total of 65 eyes from 39 patients with high myopia, who had femtosecond (FS) laser-assisted in situ keratomileusis (LASIK) surgery performed in our hospital, were included in this study. HOA and central corneal thickness were measured preoperatively and at 1 week, 1 month, and 3 months after FS-LASIK by Sirius Scheimpflug-Placido topography. Residual corneal stroma thickness (RCST) and ablation depth were measured during surgery. Horizontal coma (Z31), spherical aberration (Z40), second horizontal coma (Z51), second horizontal trefoil (Z53), pentafoil (Z55), second spherical aberration (Z60), and total HOAs were significantly increased at 1 week, 1 month, and 3 months after surgery compared with the preoperative values (P<0.05), but no significant differences were found in horizontal trefoil (Z33; P>0.05). Furthermore, Z31, Z40, and HOAs were significantly increased at 3 months post-surgery compared with the values at 1 week post-operation (P<0.05). Positive correlations were found between ablation depth and Z60 at 1 week and 1 month after surgery (r=0.291 and 0.337, respectively; P<0.05). Ablation depth was positively correlated with Z40 and Z60 at 3 months after surgery (r=0.439 and 0.336, respectively; P<0.05). The RCST/CT was negatively correlated with Z40, Z60, and HOAs at 3 months after surgery (r=-0.322, -0.412, and -0.321, respectively; P<0.05). There were no significant correlations between Zernike coefficients in terms of high-order aberration, HOAs, and RCST/CT at 1 week and 1 month post-surgery. Corneal HOAs in high myopia patients increased significantly after FS-LASIK surgery, and this was mainly observed as increases in coma and spherical aberration. The greater the ablation depth, the larger the influence on spherical aberrations. The greater the RCST/CT, the smaller the influence of HOAs on the cornea.

Reliability of iCare ic100 Rebound Tonometry and Agreement With Goldmann Applanation Tonometry in Healthy and Post-myopic LASIK Patients.

Rebound tonometry offers excellent reliability for obtaining intraocular pressure (IOP) measurements in healthy and post-myopic laser-assisted in situ keratomileusis (LASIK) patients regardless of corneal parameters and axial length and regardless of the instillation of ocular topical anesthesia. The purpose of this study was to assess the reliability of rebound tonometry, its agreement with Goldmann applanation tonometry (GAT) and its concordance after topical anesthesia in a group of nonoperated healthy patients and a group of post-myopic LASIK patients. Fifty-four patients were included in this prospective observational, case-control study. Patients were divided into 2 groups: control (n=32, 26.7±6.1 y) and LASIK (n=22, 35.8±7.6 y). Measurements of IOP were carried out using the iCare ic100 tonometer and GAT. The repeatability, intersession and interobserver reproducibility, GAT interchangeability and concordance after topical anesthesia of the iCare ic100 tonometer were assessed. Clinical reliability of the iCare ic100 was excellent in terms of repeatability [intraclass correlation coefficient (ICC)=0.909 and 0.951 in control and ICC=0.938 and 0.961 in LASIK] as well as interobserver reproducibility (ICC=0.896 in control and 0.916 in LASIK) and concordance after anesthesia (ICC=0.910 in control and 0.972 in LASIK) in both groups. Intersession reproducibility was clinically good in nonoperated patients (ICC=0.758 and 0.849) and excellent in LASIK patients (ICC=0.878 and 0.904), although statistically significant differences were obtained in the control group for both examiners (P=0.003 for examiner 1 and P=0.04 for examiner 2). Agreement with GAT was good in both groups (ICC=0.805 in control and 0.790 in LASIK), although statistically different (P<0.001 and P=0.02, respectively). Finally, the iCare ic100 reliability was independent of corneal parameters and axial length in both groups (P>0.05 for all parameters). Rebound tonometry offers good or excellent clinical reliability in both healthy and post-myopic LASIK patients. This article highlights the efficacy of iCare ic100 rebound tonometry as a reliable tool for the measurement of IOP and the management of glaucoma in healthy patients and patients undergoing myopic LASIK surgery.

Incidence and risk factors for retinal detachment following laser-assisted in-situ keratomileusis.

Purpose:The aim of this work was to study the incidence and potential risk factors for development of retinal detachment (RD) after laser-assisted in situ keratomileusis (LASIK) surgery over a long-term follow-up.Methods:This was a retrospective interventional case series. A total of 694 eyes of 352 patients were included who had undergone LASIK surgery at a tertiary eye care institute between January 2005 and September 2015 who had a minimum follow-up of 5 years after the surgery were included. Kaplan–Meier analysis and Cox proportion regression model was used to estimate the potential risk factors and cumulative risk for the development of RD.Results:Out of the total patients, 5 eyes developed RD after a mean follow-up of 7 years. The cumulative risk of RD after 1 year was 0.4%, after 2 years was 0.5% and after 7 years was 0.7%. Increased risk of RD was not associated with age at LASIK surgery, gender, laterality, and spherical equivalent (P > 0.05). A significantly increased risk for the development of RD was observed in eyes that were given prior prophylactic laser photocoagulation for peripheral lesions in multivariate cox proportional regression analysis with a hazard ratio (HR) of 9.33 (CI- 1.554-56.094; P = 0.015).Conclusion:We emphasize the need for a regular follow-up after the LASIK procedure to ensure timely treatment of any new retinal lesions.

LASIK Cerrahisi Sonrası Ağrıyı Azaltmak İçin Kullanılan Farklı Bir Yaklaşım

Objective: To evaluate the effectiveness of topical 0.4% ketorolac tromethamine usage with contact lenses following laser-assisted in situ keratomileusis (LASIK) surgery, for post-operative pain reduction. Material and Methods: Two hundred and ninety two eyes of 146 patients who underwent LASIK surgery under topical anesthesia were included in the study. Contact lenses soaked in a 0.4% solution of ketorolac tromethamine were applied to 148 eyes of 74 patients who had undergone LASIK surgery for refractive errors (Group 1). Contact lenses with no medication were applied to 144 eyes of 72 patients who had undergone LASIK surgery for refractive errors (Group 2). Pain scores were recorded in both groups every hour from hour 1 to hour 5, postoperatively. Results: There were no significant differences between the two groups with regard to age or sex (p>0.05). No significant difference was found between the two groups in respect of either preoperative or postoperative mean uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and intraocular pressure values (p>0.05). The mean postoperative UCVA was significantly better than the mean preoperative UCVA in both groups (p<0.05). Pain scores for Group 1 patients at postoperative hours 2, 3, and 4 were significantly lower than for patients in Group 2 (p<0.001, p<0.001 and p=0.023, respectively). Topical ketorolac tromethamine did not negatively affect wound healing, corneal flap, or ocular surface in any patient. Conclusion: Topical ketorolac tromethamine application with contact lenses following LASIK surgery decreases pain and discomfort effectively.

Commentary: Prophylactic laser barrage before laser-assisted in-situ keratomileusis.

The debate on prophylactic laser barrage, especially before refractive surgery, continues to divide retina specialists. There are surgeons who believe that every predisposing lesion must be treated, while some are sceptical about the preventive role of laser to the retinal lesions. Rhegmatogenous retinal detachment (RD) is common in myopes in eyes with lattice degeneration and posterior vitreous detachment (PVD).[1] Low myopes (−1.00 to −3.00 D) have a fourfold increased risk of RD over emmetropic patients. This risk increases significantly when the patient’s refractive error exceeds −3.00 D.[2] Lattice degeneration is present in 6–8% of the population and increases the risk of retinal detachment. Myopes, in addition to having peripheral retinal degenerations and lattice, have PVD at a younger age compared to emmetropes. The procedure of laser-assisted in-situ keratomileusis (LASIK) increases the risk of RD due to sudden fluctuation in the intraocular pressure (IOP) during the procedure. The increase in IOP that occurs during suction prior to engaging the microkeratome, and rapid lowering of IOP when the suction ring is decompressed, or the shock wave generated by the excimer laser may lead to PVD resulting in retinal tears.[3] Hence, LASIK patients should undergo an extensive retinal evaluation with prophylactic photocoagulation of lattice degeneration, atrophic holes, and/or flap tears in an attempt to reduce any risk of an RD. The prophylactic treatment of high-risk lesions is believed to prevent RD. Ruiz-Moreno et al. retrospectively studied 1554 consecutive eyes (878 patients) undergoing LASIK and reported a low incidence (0.25%) of RD in their patients after prophylactic barrage laser to lesions predisposing to RD.[4] Several other studies have reported a higher incidence of RD in patients who had undergone prior LASIK than would be predicted from myopia alone.[5] Till date, there have been no prospective studies directly comparing prophylactic treatment versus nontreatment and showing any definite RD risk reduction for asymptomatic retinal lesions in general. In a recent study by Srinivasan et al., of the 694 eyes that had undergone LASIK, 5 eyes (0.7%) developed RD over 7 years.[6] Increased risk of RD was not associated with age at LASIK surgery, gender, laterality and spherical equivalent. While RD was statistically significantly higher in eyes which had prior prophylactic laser photocoagulation, the number of eyes who developed RD was so low that it could not be clinically meaningful, with very wide confidence intervals of the hazard ratio. Only three eyes had lattice degeneration prior to LASIK which were lasered, and one eye with lattice was unlasered. Ideally, a study should compare a substantial number of eyes which had lattice degeneration prior to LASIK and assign them to prophylactic laser or no laser. Hence, it cannot be conclusively proven from this study that prophylactic laser adversely increases the risk of RD after LASIK. Proliferation of the epiretinal membrane (ERM) or macular pucker has been occasionally observed following treatment for a retinal break. However, a direct cause-and-effect relationship of treatment of a retinal break to ERM remains unclear. After laser photocoagulation of the retinal lesions, the adhesive force between the retina and choroid increases over a few days to 2 weeks. Hence, refractive surgery is recommended after at least 7 days following laser photocoagulation. Patients at high risk should also be educated about the symptoms of PVD and retinal detachment as well as about the value of periodic follow-up examinations. Patients should be counselled that the refractive surgery does not reduce the risk of RD, even though the refractive error may be cured after LASIK. In conclusion, all patients should have a thorough dilated indirect ophthalmoscopy with scleral depression prior to refractive surgery. Treatment of any retinal lesion predisposing to the development of RD is mandatory.

Subjective Happiness and Satisfaction in Postoperative Anisometropic Patients after Refractive Surgery for Myopia.

Laser-assisted in situ keratomileusis (LASIK) contributes to increased patient happiness one month after surgery; however, longer term effects are unknown. We performed a retrospective cross-sectional study on 472 patients who underwent bilateral LASIK surgery to measure happiness and satisfaction with LASIK, and to identify affecting factors. Patients completed questionnaires on satisfaction with the surgery and the subjective happiness scale (SHS) before, and 1, 3, 6, and 12 months after surgery. Multiple regression analyses were performed to determine independent predictors of SHS and satisfaction scores. Mean SHS increased at one month but was similar to baseline levels by six months. The SHS of older patients was greater than younger ones at baseline and at one and three months, while satisfaction among the older group was poorer at one and three months. Multiple regression analyses revealed that the decrease in SHS score from one month to three months correlated with baseline SHS, SHS at one month, uncorrected distance visual acuity (UDVA), and age. Regression analysis revealed SHS at six months correlated with preoperative SHS, SHS at one month, and satisfaction at six months. Satisfaction at final visit correlated with age, UDVA, anisometropia, and with SHS at each visit. We conclude that happiness and satisfaction were age- and UDVA-dependent, and anisometropic patients report poorer satisfaction scores.

Early changes in tear film protein profiles after femtosecond LASIK surgery

BackgroundFemtosecond laser-assisted in situ keratomileusis (LASIK) has proven to be an efficacious, predictable, and safe procedure for the correction of refractive errors. We examined the early tear protein changes of patients undergoing LASIK surgery in order to better understand the mechanisms and proteins related to laser corneal surgery and initial recovery.MethodsCorneal flaps were created with Ziemer FEMTO LDV Z6 I femtosecond laser and stroma was ablated using Wavelight EX500 excimer laser. Tear samples were collected preoperatively as well as 1.5 h and 1 month after LASIK treatment using glass microcapillary tubes. Relative quantification of tear proteins was performed with sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS).ResultsSWATH-MS revealed that 158 proteins had altered expression levels 1.5 h after the operation. Two-thirds of these proteins, mostly connected to migration and inflammation response, returned to preoperative levels within the first postoperative month. The other proteins, which did not return to baseline levels, included proteins connected to for example epithelial barrier function. We also identified several proteins, which correlated with surgical variables, such as the amount of correction, flap thickness and flap diameter.ConclusionsThe present study showed that an uneventful femtosecond LASIK refractive surgery induced a significant immune cell migration and inflammation-associated changes in tear proteomics profile quickly after the operation, but the expression of most proteins recovered almost completely to the preoperative levels within the first month. The individual proteins identified in our study are potential targets for the follow-up and modification of LASIK-induced biochemical processes.

Combined Topo-Guided laser Vision Correction (LASIK) with Concurrent Prophylactic High-Fluence Corneal Collagen Crosslinking (CXL) in Myopic Patients with Normal Cornea

Background: Corneal ectasia is a serious vision-threatening complication of laser-assisted in-situ keratomileusis (LASIK). Objective: The aim of the work was to evaluate the efficacy and safety of ultraviolet A (UVA) irradiation crosslinking in concurrent with LASIK in myopic patient with normal cornea to avoid post LASIK ectasia. Patients and Methods: This Prospective randomized interventional study included 60 eyes of 30 consecutive patient who were scheduled for LASIK surgery, all of them were myopic with normal cornea with no pervious refractive surgery. They were candidate for Combined Topo-Guided LASIK with accelerated CXL. This was done in a private eye hospital between Jun 2018 and Jun 2019. Results: The preoperative uncorrected visual acuity (UCVA) ranged from 0.05- 0.1 with mean 0.075±0.02 and preoperative best corrected visual acuity (BCVA) ranged 0.2- 1.0 with mean 0.58±0.13 and post-operative UCVA at 6 months showed ranged 0.2-1.0 with mean 0.55±0.16, and postoperative UCVA at 1 year showed ranged 0.2-1.0 with mean 0.56±0.13,. The improvement in visual acuity from 0.075±0.02 UCVA preoperatively show statistically significant difference (P > 0.05) because we compared the results with the preoperative BCVA 0.58±0.13 postoperatively at 6 months. However, t-Paired Sample t-test; p-value < 0.05 S. Conclusion: It could be concluded that LASIK combined with a prophylactic CXL intervention appears to provide predictability as well as refractive and keratometric stability. The data reported in this study provide evidence of the safety and efficacy of this approach.

Evaluation of Retinal Ganglion Cell Layer Thickness in the Early Period After Femtosecond LASIK Surgery

Objectives:To evaluate the early effects of femtosecond laser-assisted in situ keratomileusis (LASIK) surgery on retinal ganglion cell thickness (GCT), peripapillary retinal nerve fiber thickness (NFT), and central macular thickness (CMT) obtained by spectral domain optical coherence tomography (SD-OCT) in a healthy population.Materials and Methods:This case-control study included data from the right eye of 40 subjects without any disease other than refractive error and who had undergone femtosecond LASIK surgery. The preoperative, postoperative 1-hour, and postoperative 3-week GCT, NFT, and CMT values obtained by SD-OCT were compared.Results:The mean age was 27.54±5.99 years (18-45 years). GCT, NFT, and CMT were 18.43±6.03 μm, 107.90±9.01, and 234.3±21.2 μm preoperatively; 18.05±5.93 μm, 108.08±8.92 μm, and 230.1±22.6 μm at postoperative 1 hour; and 17.86±5.27 μm, 107.98±10.13, and 236.3±25.1 μm at postoperative 3 weeks (p=0.159, 0.85, and 0.254, respectively).Conclusion:There were no changes in GCT, NFT, and CMT values evaluated with SD-OCT in the early period after femtosecond LASIK surgery.

Prophylactic corneal cross-linking in LASIK surgery: effects on visual outcome and recovery time

Introduction: Collagen cross-linking is a useful adjunct in preventing corneal ectasia after laser-assisted in situ keratomileusis (LASIK). This study aimed to evaluate whether prophylactic cross-linking in IntraLase LASIK affects optimum visual outcome and recovery time in the immediate post-surgery period and is associated with any side effects.&#x0D; Methods: This was a retrospective case study on the right eyes of 100 Chinese subjects aged 18 to 40 years who underwent IntraLase LASIK. Fifty subjects who underwentcross-linking after completing LASIK (Group A) were compared with 50 subjects who did not undergo LASIK (Group B). Cases were evaluated for pre- and post-operative spherical equivalent, uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), recovery time and presence of side effects.&#x0D; Results: At 1 week post-LASIK, mean (SD) UDVA of Group A subjects was poorer than Group B, at 1.05 (0.19) vs 1.17 (0.19) (p = 0.036); however, there was no significant difference in CDVA (p = 0.095). By 1 month post-LASIK, differences in both UDVA and CDVA were insignificant (p = 0.055, 0.106, respectively). Mean recovery time was 2.72 (95% confidence interval [CI] = 0.64-4.7) days longer in Group A (p = 0.010), although by 1 month post-LASIK, both groups were able to achieve CDVA equal to or better than that achieved pre-LASIK. Incidence of mild inflammation and dry eyes post-LASIK was similar in both groups (p = 1.00, 0.749, respectively); no other complications were observed.&#x0D; Conclusion: No differences in visual outcomes at and occurrence of side effects at 1 month post-LASIK were observed between subjects who underwent cross-linking prior to refractive surgery and those who did not. However, the group that underwent cross-linking had a slightly longer mean recovery time. Our study supports prophylactic cross-linking as a safe procedure that does not affect immediate visual outcomes among the Chinese population when used in adjunct with LASIK surgery.

The risk of vision loss in contact lens wear and following LASIK.

To compare the risk of vision loss following contemporary laser-assisted in situ keratomileusis (LASIK) with different types and modality of use of contact lenses. Data from a previously published study were used to derive the incidence of vision loss (≥ 2 line loss of best corrected spectacle acuity) following microbial keratitis for different contact lens types and wearing modality, stratified by duration of lens wear. A literature search on vision loss following LASIK was performed between 2003 and 2019. The prevalence of vision loss at six months post-surgery was captured from clinical trials published after 2003. A proportion meta-analysis was applied to derive the prevalence of vision loss following LASIK. A least-squares fitting of cumulative vision loss (P, /10000 wearers) over time (t, years) using an exponential model estimated the years of contact lens wear to which the risk of vision loss with LASIK was equivalent. Vision loss following LASIK occurred in 66 (95% confidence interval [CI] 34-108) per 10000 wearers. As a conservative estimate based on the lower confidence interval of the estimated equivalent years of contact lens wear, daily wear contact lenses and extended overnight silicone wear hydrogel contact lens need to be worn for 103 (95% [CI] 103-391) and 25 (95% [CI] 25-79) years respectively, to equal the rate of vision loss equivalent to a one-off LASIK procedure. The risk of vision loss to the individual is low with either contact lens wear or refractive surgery. Contact lens wear does not pose a higher risk of vision loss than LASIK surgery for the most common wear modalities.

Https://www.djo.org.in/articles/30/3/Surgical-Management-of-Strabismus-in-Thyroid-Ophthalmopathy.html

LASIK (Laser Assisted Insitu keratomileusis) is the most commonly performed refractive surgery worldwide. A detailed pre operative and post operative evaluation of the anterior and posterior segment is a must. A 35 year old male patient with a history of LASIK surgery done 13 years back presented to us with complaint of painless, progressive diminution of vision in both eyes from past 2 years. Dilated retinal examination showed bulls eye maculopathy in both eyes. Macular OCT showed gross reduction in central foveal thickness. ERG showed marked reduction in photopic responses suggestive of a cone dystrophy. Treatment aims at alleviating the symptoms and use of low vision aids. Genetic counselling may be of benefit for affected individuals and their families.