Postoperative Astigmatism after Keratoplasty: A Systematic Review Meta-Analysis Based on PRISMA.

Background: The number of corneal transplants is rising, with the aim to treat a spectrum of diseases ranging from dystrophies to corneal opacities caused by trauma or chemical burns. Refractive outcomes after this procedure are often impossible to predict and associated with high levels of astigmatism. However, there are many techniques that affect the reduction of astigmatism and improve the quality of life of patients. Objectives: The aim was to compare the improvement in postoperative visual acuity (logMAR) and amount of corneal astigmatism (Diopters) after corneal keratoplasty in patients who additionally underwent a surgical procedure, which affects the reduction in postoperative astigmatism, and to determine the most effective method. Search Methods and Selection Criteria: A thorough search was carried out across online electronic databases including PubMed, Embrase, Ovid MEDLINE, Scopus, and Web of Science, using combinations containing the following phrases: postoperative astigmatism, post-keratoplasty astigmatism, anterior lamellar keratoplasty (ALK), deep anterior lamellar keratoplasty (DALK), posterior lamellar keratoplasty, endothelial keratoplasty (EK), penetrating keratoplasty (PK), corneal transplant, keratoplasty, refractive surgery, kerato-refractive surgery, laser in situ keratomileusis (LASIK), and femtosecond LASIK. This was to determine all English-language publications that discuss refractive operations for postoperative or post-keratoplasty astigmatism. These bibliographies were searched for English-language publications published between 2010 and 2023. We proceeded to review each detected record's reference list. Data Extraction: Study characteristics such as study design, sample size, participant information, operations performed, and clinical outcomes were all extracted. Data Statistical Analyses: The Comprehensive Meta-Analysis software (version 3.3.070, 2014) was used to perform the analysis. The threshold of 0.05 for p-values was considered statistically significant. All effect sizes are reported as standardized differences (Std diff) in means with a 95% confidence interval (CI) and visualized graphically as forest plots. Publication bias is presented as a funnel plot of standard error by Std diff in means. Four methods were used to evaluate the heterogeneity among the studies: Q-value, I2, chi-square (χ2), and tau-squared. Main Results: We included 21 studies that randomized 1539 eyes that underwent corneal transplantation surgery either by PKP, DALK, or DSEAK techniques. The results showed the most significant improvement in the visual acuity and significant decrease in the corneal astigmatism after laser surgery procedures, like femtosecond-assisted keratotomy after DALK and PKP and LASIK after DSEAK.

Topographic and Surgical Risk Factors for Early Myopic Regression between Small Incision Lenticule Extraction and Laser In Situ Keratomileusis.

Our objective was to evaluate the topographic and surgical factors of early myopic regression between laser in situ keratomileusis (LASIK) and small-incision lenticule extraction (SMILE). A retrospective case-control study was conducted, and 368 and 92 eyes were enrolled in the LASIK and SMILE groups via propensity score matching (PSM). Visual acuity, refractive status, axial length, and topographic/surgical parameters were collected. Multiple linear regression was applied to the yield coefficient and the 95% confidence interval (CI) of the parameters. The cumulative incidence of early myopic regression was higher in the LASIK group (p < 0.001). In the SMILE group, a lower central corneal thickness (CCT) thinnest value and a higher corneal cylinder associated with early myopic regression were observed; meanwhile, in the LASIK group, a lower CCT thinnest value, a higher steep corneal curvature, a larger optic zone, and a lower flap thickness related to early myopic regression were observed (all p < 0.05). In the SMILE group, a higher CCT difference correlated with early myopic regression was observed compared to the LASIK group (p = 0.030), and higher steep corneal curvature and lower cap/flap thickness (both p < 0.05) correlated with early myopic regression were observed in the LASIK group compared to the SMILE group. In conclusion, CCT differences significantly influence early myopic regression in the SMILE group; meanwhile, corneal curvature and flap thickness affect early myopic regression principally in the LASIK group.

Refractive outcomes using Barrett formulas and patient characteristics of cataract surgery patients with and without prior LASIK/PRK.

PURPOSE: The goal of this study is to describe characteristics of cataract surgery patients who previously underwent laser in situ keratomileusis/photorefractive keratectomy (LASIK/PRK) in comparison to non-LASIK/PRK cataract surgery patients including psychiatric comorbidities, as well as describe refractive prediction error after cataract surgery while accounting for axial length (AL) using the Barrett True-K and Barrett Universal II formulas. METHODS: This was a retrospective study of patients from the University of Colorado Cataract Outcomes Registry. The primary outcomes were refraction prediction error (RPE), mean absolute RPE, and median absolute RPE. Outcomes were stratified by five axial length groups. Univariate and multivariate models for RPE were stratified by the AL group. RESULTS: Two hundred eighty-one eyes with prior LASIK/PRK and 3101 eyes without are included in the study. Patients with prior LASIK/PRK were significantly younger: 67.0 vs 69.9 years, p < 0.0001. The LASIK/PRK group had significantly better mean pre-operative BCVA in comparison to the non-LASIK group, logMAR 0.204 vs logMAR 0.288, p = 0.003. The LASIK/PRK group had significantly lower rates of cardiovascular disease (18.5% vs 29.3%, p < 0.001), hypertension (49.1% vs 59.3%, p < 0.012), and type 2 diabetes (10.7% vs 26.0%, p < 0.001), and no significant difference in psychiatric disease. The absolute RPE was higher for the LASIK group for all ALs, but only significantly higher for eyes with AL less than 25 mm. CONCLUSION: Patient eyes with prior LASIK/PRK surgery undergoing cataract surgery were significantly younger, had significantly less comorbidities, and a significantly better pre-operative BCVA. Using the Barrett formulas, absolute prediction error for eyes with longer ALs was not significantly worse for LASIK/PRK eyes than those without and the difference was smaller for eyes with longer AL.

Clinical Evaluation of Corneal Endothelial Parameters following Laser Refractive Surgery in Myopic Eyes: A Review.

Background: The aim of this review was to investigate the influence of various laser refractive surgery methods on the corneal endothelium in myopic patients. The role of the corneal endothelium in laser refractive surgery (LRS) is currently being addressed in the assessment of postoperative corneal edema risk. Methods: Changes in corneal endothelial cell density and morphology after LRS were evaluated based on a systematic review of current studies. The results of a literature search in the PubMed, Science Direct, Google Scholar, and the Web of Science databases, as well as a manual search, were selected for the final review according to the PRISMA 2020 flow diagram. Results: We included 24 prospective clinical trials in the review: surface ablation (twelve), LASIK and FemtoLASIK (two), femtosecond lenticule extraction (two), and comparable studies (eight). Endothelial cell density was determined by specular or in vivo confocal microscopy. In most studies, no statistically significant differences were found between preoperative and postoperative endothelial parameters. In nine studies, the changes were statistically significant, but no vision-threatening complications occurred, and no serious corneal complications developed in any eyes during the follow-up period. Conclusions: Based on collected data, laser keratorefractive surgery appears not to exert a significant effect on the corneal endothelium.

Surgical outcomes of laser in situ keratomileusis (LASIK) in patients with stable systemic disease.

PURPOSE: To evaluate the surgical outcome in terms of safety, efficacy, predictability, and retreatment rate of LASIK surgery in patients with controlled systemic diseases in comparison with healthy individuals. METHODS: The retrospective study included data from 1936 eyes of 976 patients with stable systemic diseases who underwent LASIK surgery between January 2016 and June 2019. The safety, efficacy, predictability of the surgery, and retreatment rate were evaluated in comparison with a control group comprising 1951 patients. The study was approved by the local ethics committee and adhered to the principles of the Declaration of Helsinki. Statistical analysis was performed using R team and the level of statistical significance was set at p < 0.05. RESULTS: All treatment groups demonstrated high safety and efficacy indices after LASIK surgery. Furthermore, the study arms demonstrated comparable predictability and retreatment rates to the control group in nearly all cases. Retreatment rates were significantly higher in the rheumatoid arthritis group (p = 0.03), while safety indices were significantly lower in the hay fever group compared to the control group (p = 0.004). No intra- or postoperative sight-threatening complications were documented. CONCLUSION: Our findings suggest that selected patients with stable systemic conditions can safely undergo LASIK surgery and achieve comparable outcomes to healthy individuals. Further research is needed to better understand the treatment outcomes in this challenging patient population.

Neurogenic dry eye associated with intravitreal injection of anti-VEGF agents.

PURPOSE: To report a case of neurogenic dry eye (NDE) that developed after intravitreal ranibizumab injection (IVR). CASE REPORT: A 71-year-old woman had a history of cataract phacoemulsification and intraocular lens (IOL) implantation, Nd:YAG laser posterior capsulotomy and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). Aneurysmal dilatation of the inferior temporal retina was found in the left fundus, which was diagnosed as retinal aneurysm, and intravitreal ranibizumab injection was administered. Dry eye was found in the left eye after the first injection. After the second injection, the patient developed severe dry eye with left eye dryness, photophobia, irritation, and blurred vision. The tear film breakup time (TBUT) value was 3 s, the Schirmer test value was 2 mm/5 min, corneal fluorescein staining (CFS) showed diffuse patellar staining of the corneal epithelium with a staining area of >50% and irregular staining at the edge of the corneal flap, and the corneal touch threshold value in the filament length was 1.5 cm in the left eye. CONCLUSIONS: Patients with a history of intraocular lens implantation, Nd:YAG laser posterior capsulotomy, and femtosecond laser-assisted laser in situ keratomileusis surgery may have increased drug permeability due to an increased concentration of anti-VEGF drugs in the aqueous layer and thinning of the stromal layer of the cornea. The corneal subepithelial nerve repair mechanism was destroyed, causing neurogenic dry eye.

Differences in change of post-operative antioxidant levels between laser-assisted lenticule extraction and femtosecond laser in situ keratomileusis.

To evaluate the change of total antioxidant capacity (TAC) and ascorbic acid (AA) between femtosecond laser in situ keratomileusis (FS-LASIK) and laser-assisted lenticule extraction (LALEX). A prospective non-randomized study was conducted, and 33 and 75 eyes that had undergone FS-LASIK or LALEX surgeries were enrolled, respectively. The tear films near corneal incisions were collected, and the concentrations of TAC and AA were determined. The generalized linear mixed model was adopted to calculate the adjusted odds ratio (aOR) with 95% confidence interval (CI) of TAC and AA between the two groups. The AA reduction was significant 1 month after the LALEX and FS-LASIK procedures (both p < 0.05), and the decrement in AA level was significantly larger in the FS-LASIK group compared to the LALEX group (p = 0.0002). In the subgroup analysis, the LALEX group demonstrated a lower decrement in TAC level in the individuals with dry eye disease (DED) than the FS-LASIK group (p = 0.0424), and the LALEX group demonstrated a significantly lower AA decrement in the participants with high myopia (p = 0.0165) and DED (p = 0.0043). The LALEX surgery causes lesser AA decrement compared to FS-LASIK surgery especially for the patients with DED.

Cataract surgery following refractive surgery: Principles to achieve optical success and patient satisfaction.

A growing number of patients with prior refractive surgery are now presenting for cataract surgery. Surgeons face a number of unique challenges in this patient population that tends to be highly motivated to retain or regain functional uncorrected acuity postoperatively. Primary challenges include recognition of the specific type of prior surgery, use of appropriate intraocular lens (IOL) power calculation formulas, matching IOL style with spherical aberration profile, the recognition of corneal imaging patterns that are and are not compatible with toric and/or presbyopia-correcting lens implantation, and surgical technique modifications, which are particularly relevant in eyes with prior radial keratotomy or phakic IOL implantation. Despite advancements in IOL power formulae, corneal imaging, and IOL options that have improved our ability to achieve targeted postoperative refractive outcomes, accuracy and predictability remain inferior to eyes that undergo cataract surgery without a history of corneal refractive surgery. Thus, preoperative evaluation of patients who will and will not be candidates for postoperative refractive surgical enhancements is also paramount. We provide an overview of the specific challenges in this population and offer evidence-based strategies and considerations for optimizing surgical outcomes.

Corrective effect of femtosecond laser assisted laser in situ keratomileusis Xtra on patients with moderate to high myopia after 2a postoperatively / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To evaluate corrective effect and stability of corneal morphology in patients with moderate to high myopia after 2a treatment of femtosecond laser assisted laser in situ keratomileusis(FS-LASIK)Xtra.METHODS:Retrospective case-control study. A total of 30 cases(58 eyes)Patients with moderate to high myopia combined with astigmatism who planned to undergo refractive surgery in our hospital from August 2019 to August 2020 were included, and different types of surgery were performed respectively based on the relevant index of keratoconus screening in the preoperative corneal topography. They were divided into FS-LASIK group and Xtra group, with 15 cases(29 eyes)in each group. Uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), spherical equivalent(SE)and the corneal curvature of the anterior and posterior surfaces of different diameters(3, 5 and 7 mm)measured by Sirius three-dimensional corneal topography were observed preoperatively and 3 mo, 1 and 2 a postoperatively.RESULTS: The UCVA of the two groups of patients at different time points after surgery was significantly increased compared with preoperatively(both P&#x0026;#x003C;0.01), and there was no difference in UCVA and SE between the two groups(P&#x0026;#x003E;0.05). After 2 a postoperatively, residual astigmatism was -0.25-0 D in 25 eyes(86%)of the FS-LASIK Xtra group and 24 eyes(83%)of the FS-LASIK group. The actual corrected SE and expected corrected SE of both groups were positively correlated(both P&#x0026;#x003C;0.05). There were differences in corneal curvature on the surface of different diameter areas(3, 5, and 7 mm)between the two groups at 3 mo, 1, and 2 a postoperatively compared with preoperatively. After 1 and 2 a postoperatively, the corneal posterior surface curvature of the FS-LASIK Xtra group with corneal diameter of 3 and 5 mm was higher than that of the FS-LASIK group(P&#x0026;#x003C;0.05).CONCLUSIONS:FS-LASIK Xtra has good safety, efficacy and predictability in correcting patients with moderate to high myopia.

Small incision lenticule extraction for the treatment of myopic anisometropia / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To explore the clinical effect of small incision lenticule extraction(SMILE)on the treatment of myopic anisometropia.METHODS: Clinical data of 76 patients(146 eyes)with myopic anisometropia who received SMILE or femtosecond assisted laser in situ keratomileusis(FS-LASIK)in our hospital from January 2021 to December 2022 were retrospectively analyzed. The patients were divided into SMILE group(39 cases, 77 eyes)and FS-LASIK group(37 cases, 69 eyes)according to surgical methods. Uncorrected visual acuity(UCVA), diopter, anisometropia, corneal aberration and occurrence of postoperative complications were compared between the two groups at 1 wk, 1 and 3 mo after surgery.RESULTS: The UCVA of the two groups was improved after surgery compared with that before surgery, and the coma, trefoil, spherical aberration and total higher-order aberration were significantly increased compared to those before surgery(P&#x003C;0.05), and the coma, trefoil, spherical aberration and total higher-order aberration in the FS-LASIK group were significantly higher than those in the SMILE group(P&#x003C;0.05). After follow-up to 3 mo after surgery, the incidence of postoperative complications was significantly lower in the SMILE group than that in the FS-LASIK group(5.2% vs 15.9%, P&#x003C;0.05).CONCLUSION: Both SMILE and FS-LASIK can effectively enhance the UCVA and improve the visual quality in patients with myopic anisometropia, but SMILE has lower corneal higher order aberrations, lower incidence of postoperative complications and better overall effect.

Femtosecond laser applications in corneal surgery.

Femtosecond laser (FSL) applications in corneal surgery have increased since its inception. Corneal surgery has undergone a tremendous transformation thanks to the introduction of FSL technology. This laser makes precise, three-dimensional incisions while causing minimal damage to surrounding tissue. This review updates and summarizes current and upcoming FSL applications in corneal surgery, current commercially available FSL, and its respective applications. Refractive surgery applications include laser in-situ keratomileusis flaps, refractive corneal lenticule extraction such as small incision lenticule extraction, astigmatic keratotomy, intracorneal ring segments tunnels for keratoconus including corneal allogenic intrastromal ring segments, and presbyopia treatments with intrastromal pockets for corneal inlays and intrastromal incisions (INTRACOR). Keratoplasty applications include penetrating keratoplasty trephination; superficial and deep anterior lamellar keratoplasty trephination, lamellar dissection, and tunnel creation; posterior lamellar keratoplasty donor and recipient preparation; Bowman layer transplantation donor, and recipient preparation; and stromal keratophakia. Other applications include conjunctival graft preparation in pterygium surgery, and keratopigmentation (corneal tattooing). FSL is a surgical instrument widely used in corneal surgery because it improves reproducibility and safety in many procedures.

Effective optical zone following small incision lenticule extraction: a review.

Small incision lenticule extraction (SMILE) is a "flapless" keratorefractive surgery with excellent safety, efficacy, stability, and predictability for myopia correction. A recent global multicenter study also reported good refractive outcomes for hyperopic SMILE. SMILE has shown advantages including improved biomechanical strength, fewer dry eye symptoms, less corneal denervation, and fewer surgery-induced higher-order aberrations over laser in situ keratomileusis (LASIK). However, night vision complaints, including glare, halos, and starbursts, could still occur after SMILE. These symptoms have been proven to be closely related to the effective optical zone (EOZ), which is defined as the achieved area of corneal ablation. A larger postoperative EOZ may indicate better visual quality, making EOZ an important safety parameter for keratorefractive surgeries. As SMILE has gained wider application globally, the EOZ following SMILE has also been increasingly studied in the field of refractive surgery. This review provides an update on topics related to the EOZ after SMILE, including its measurement and influencing factors, aiming to benefit the personalization of the surgical algorithm and ultimately improve the visual quality after the SMILE procedure.

Effect of preoperative pupil offset on corneal higher-order aberrations after femtosecond laser-assisted in situ keratomileusis.

BACKGROUND: This study aimed to investigate the relationship between multiple higher-order aberrations (HOAs) subgroups and pupil offset, as well as to analyze the factors affecting postoperative corneal HOAs in patients with different degrees of refractive errors. METHODS: We enrolled 160 patients (316 eyes) aged ≥ 18 years who had undergone femtosecond laser-assisted in situ keratomileusis (FS-LASIK) treatment. Based on the relationship between the preoperative pupil offset and the postoperative ΔHOAs, all patients were divided into two groups: group I (pupil offset ≤ 0.20 mm) and group II (pupil offset > 0.20 mm). All of the eyes had low to high myopia with or without astigmatism (manifest refraction spherical equivalent (MRSE) < -10.00 D). Uncorrected distance visual acuity, corrected distance visual acuity, MRSE, pupil offset, central corneal thickness, corneal HOAs, vertical coma (Z3-1), horizontal coma (Z31), spherical aberration (Z40), trefoil 0° (Z33), and trefoil 30° (Z3-3) over a 6 mm diameter central corneal zone diameter were evaluated preoperatively and at 1 and 3 months postoperatively. RESULTS: Our result revealed significant differences in postoperative corneal total root mean square (RMS) HOAs, RMS vertical coma, RMS horizontal coma, RMS spherical aberration, and RMS trefoil 30° between group I and group II. ΔMRSE was found to be an effective factor for ΔRMS HOAs (R2 = 0.383), ΔRMS horizontal coma (R2 = 0.205), and ΔRMS spherical aberration (R2 = 0.397). In group II, multiple linear regression analysis revealed a significant correlation between preoperative pupillary offset and Δtotal RMS HOAs (R2 = 0.461), ΔRMS horizontal coma (R2 = 0.040), and ΔRMS trefoil 30°(R2 = 0.089). The ΔRMS vertical coma effect factor is the Y-component, and the factor influencing ΔRMS spherical aberration was ΔMRSE (R2 = 0.256). CONCLUSION: A small pupil offset was associated with a lower induction of postoperative corneal HOAs. Efforts to optimize centration are critical for improving surgical outcomes in patients with FS-LASIK.

Analysis of visual quality after multifocal intraocular lens implantation in post-LASIK cataract patients.

With the development of refractive corneal surgery, excimer laser in situ keratomileusis (LASIK) has become a common refractive surgery procedure. However, post-LASIK patients are at increased risk of developing cataracts as they age and often require IOL implantation. The choice of IOLs is particularly important for these patients, who have smaller residual refractive error and have higher requirements for post-cataract vision recovery and visual quality than the general population. Multifocal IOLs are widely used in clinical practice for patients with high visual acuity needs, such as cataract patients after refractive keratomileusis, due to their advantages of providing excellent near and distance visual acuity; however, compared to monofocal IOLs, multifocal IOLs can lead to postoperative problems related to visual quality such as increased higher order aberrations and decreased contrast sensitivity. Therefore, whether multifocal IOLs have advantages for post-LASIK cataract patients, such as improving the visual quality of such patients, has attracted attention. In this paper, we analyze the current status of research on the implantation of multifocal IOLs in post-LASIK cataract patients by domestic and foreign experts, review and summarize the relevant literature, and propose further discussion in the context of the actual situation of postoperative visual quality and vision recovery.

Visual outcomes of early enhancement following small incision lenticule extraction versus laser in situ keratomileusis.

Purpose: To compare visual outcomes of early enhancement following small incision lenticule extraction (SMILE) versus laser in situ keratomileusis (LASIK). Methods: Retrospective analysis of eyes (patients operated in the setting of a tertiary eye care hospital between 2014 and 2020) requiring early enhancement (within one year of primary surgery) was conducted. Stability of refractive error, corneal tomography, and anterior segment Optical Coherence Tomography (AS-OCT) for epithelial thickness was performed. The correction post regression was done using photorefractive keratectomy and flap lift in eyes, wherein the primary procedure was SMILE and LASIK, respectively. Pre- and post enhancement corrected and uncorrected distance visual acuity (CDVA and UDVA), mean refractive spherical equivalent (MRSE), and cylinder were analyzed. IBM SPSS statistical software. Results: In total, 6350 and 8176 eyes post SMILE and LASIK, respectively, were analyzed. Of these, 32 eyes of 26 patients (0.5%) post SMILE and 36 eyes of 32 patients (0.44%) post-LASIK required enhancement. Post enhancement (flap lift in LASIK, and PRK in SMILE group) UDVA was logMAR 0.02 ± 0.05 and 0.09 ± 0.16 (P = 0.009), respectively. There was no significant difference between the refractive sphere (P = 0.33) and MRSE (P = 0.09). In total, 62.5% of the eyes in the SMILE group and 80.5% in the LASIK group had a UDVA of 20/20 or better (P = 0.04). Conclusion: PRK post SMILE demonstrated comparable results to flap lift post LASIK and is a safe and effective approach for early enhancement post SMILE.

Retrospective diagnosis of naked eye visual acuity (UCVA) variations in patients with refractive errors treated with SMILE, LASIK, and WF-LASIK refractive surgery.

A retrospective assessment of the visual acuity (UCVA) variations in bare eyes of the refractive error cases treated with SMILE, LASIK and WF-LASIK. A retrospective selection of 126 patients with refractive error treated by refractive surgery admitted to our hospital between January 2019 and December 2021 were divided into three separate sets of patients according to their surgical methods: the SMILE cohort, the LASIK cohort, and the WF-LASIK cohort, and the three sets of patients were analyzed for bare eye visual acuity, refraction, higher-order aberration, BUT, SIt index, and complications, and the recovery effects of patients with the three surgical procedures. All three types of refractive surgery, SMILE, LASIK and WF-LASIK, can yield good surgical results in the reduction of refractive error, and patients with SMILE have better postoperative tear film stability, while patients with WF-LASIK have the best postoperative visual quality.

Laser in situ keratomileusis versus Artisan lens implantation in correcting ametropia after penetrating keratoplasty for keratoconus.

PURPOSE: To compare the long-term safety and efficacy of laser in situ keratomileusis (LASIK) with Artisan phakic intraocular lens implantation to correct refractive errors after penetrating keratoplasty (PK) for keratoconus. METHODS: This retrospective comparative interventional case series included a total of 33 consecutive keratoconus eyes that had previous PK and received subsequent LASIK (n = 16) or Artisan lens implantation (n = 17) were included in this study. Outcome measures were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive error, and complications. RESULTS: Postoperatively, the UDVA of ≥20/40 was achieved in none of the LASIK group compared to 62.5% of eyes in the Artisan group (P < 0.001); the respective values for CDVA of ≥20/40 were 87.5 and 94.1% (P = 0.51). Spherical equivalent refraction decreased from - 6.97 ± 1.50 D preoperatively to - 4.20 ± 2.05 D postoperatively in the LASIK group (P < 0.001) and from - 10.79 ± 2.15 D preoperatively to - 2.13 ± 1.23 D postoperatively in the Artisan group (P < 0.001). There was no significant change in the refractive astigmatism in LASIK group (P = 0.30) or Artisan group (P = 0.11). The efficacy and safety indices were significantly better for Artisan (0.82 ± 0.34 and 1.13 ± 0.30, respectively) than for LASIK (0.22 ± 0.17 and 0.85 ± 0.24, respectively, P ≤ 0.006 for both comparisons). While refractive error changed significantly from postoperative year 3 to the final visit in the LASIK group, it remained stable in the Artisan group through follow-up period. No significant complications were observed in any group. CONCLUSION: Artisan lens implantation provided superior and stable visual outcomes compared to LASIK for the management of post PK refractive errors in keratoconus eyes.

Higher-Order Aberrations of Topography-Guided LASIK and Wavefront-Optimized LASIK in High- and Low-Myopic Eyes: A Non-Randomized Controlled Trial.

We aimed to investigate high-order aberration (HOA) change between topography-guided (TG) and wavefront-optimized (WFO) laser in situ keratomileusis (LASIK) in patients with different degrees of myopia. A non-randomized clinical trial was conducted, in which 40 eyes of 20 patients aged 20-50 years old were included. Participants received TG-LASIK in one eye and WFO-LASIK on the alternate eye. Corneal topography and HOAs including coma, trefoil, spherical aberration (SA), and contrast sensitivity (CS) were collected. Moreover, a quality of vision (QoV) questionnaire was completed by each participant. Non-parametric tests were used to infer the difference in HOAs and CS between the TG-LASIK and WFO-LASIK groups, and subgroup analyses stratified by myopia degree were performed. The high-myopia patients with TG-LASIK showed more coma and SA compared to low-myopia individuals (all 95% CI lower limits > 0), and subjects who received WFO-LASIK exhibited more SA in high-myopia status (both 95% CI lower limits > 0). The TG-LASIK group showed lower postoperative trefoil compared to the WFO-LASIK group in the high-myopia population (mean difference: -0.1267, 95% CI: -0.24 to -0.01). The TG-LASIK group yielded less surgically induced haze, better clarity at night, and better total quality scores (all p < 0.05). In conclusion, TG-LASIK might yield less postoperative trefoil in high-myopia patients and higher QoV in the general population compared to the WFO-LASIK procedure.

Transient change in the binocular visual function after femtosecond laser-assisted in situ keratomileusis for myopia patients.

Purpose: The goal of this study was to compare the difference in binocular visual function for high and low-moderate myopes before and after femtosecond laser-assisted in situ keratomileusis (FS-LASIK). Methods: Thirty-three subjects (17 males and 16 females) were divided into two groups according to their preoperative refractive errors in spherical equivalent (SE): low-moderate myopia group (SE ≥-6.00 D) and high myopia group (SE <-6.00 D). The binocular visual function including accommodative amplitude (AA), accommodative facility (AF), positive and negative relative accommodation (PRA and NRA, respectively), horizontal phoria measurement, positive and negative fusion vergence, accommodative-convergence over accommodation (AC/A) ratio, and stereopsis were assessed with the best-corrected vision before patients received FS-LASIK and 7 and 30 days after the surgery. Repeated measures analysis of variance (ANOVA) was applied to study the change in binocular visual function. Results: The AF values in both groups were significantly reduced after 7 days of FS-LASIK (baseline vs. day 7 (mean): high myopia group: 7.85 vs. 5.62 cpm, repeated ANOVA, P = 0.01; low-moderate myopia group: 5.95 vs. 4.40 cpm, repeated ANOVA, P = 0.04). This change returned to the baseline level 30 days after the operation. In addition, the horizontal phoria values in both groups were significantly reduced for both distant (P = 0.019 and P = 0.001, respectively) and near (P = 0.003 and P = 0.049, respectively) 7 days after the operation, but they rebound to preoperative state after 30 days. Conclusion: A transient change in binocular visual function was noticed after 7 days of FS-LASIK operation, which could cause symptoms of asthenopia. Our data showed all the binocular visual functions returned to baseline level after 30 days of operation.

Small incision lenticule extraction and femtosecond-assisted laser in situ keratomileusis in patients with deep corneal opacity: case series.

AIM: To report the safety, efficacy, and accuracy of small-incision lenticule extraction (SMILE) or femtosecond-assisted laser in situ keratomileusis (FS-LASIK) for the correction of myopia or myopic astigmatism in patients with deep corneal opacity denoted by anterior segment optical coherence tomography (AS-OCT). METHODS: Four patients with monocular corneal opacity (3 due to mechanical injury, 1 due to a firecracker wound) were recruited and treated with refractive surgery (3 for SMILE, 1 for FS-LASIK combined with limbal relaxing incision (LRI). Preoperative ocular manifestations, surgical details, postoperative visual outcomes, corneal opacity parameters, and corneal topography were analyzed. RESULTS: Preoperatively, spherical diopter ranged from -3.0 D to -4.75 D with cylinder ranging from -0.75 to -5.0 D, and corrected distance visual acuity (CDVA) ranging from 20/25 to 20/20. One eye's corneal opacity was located in the central zone and three were in the mid-peripheral optical zone. Three patients underwent uneventful SMILE in both eyes, whilst one patient underwent FS-LASIK for high astigmatism in both eyes and LRI in the right eye. CDVA of the eye with corneal opacity ranged from 20/22 to 20/20 one to six weeks postoperatively. Two patients achieved better CDVA and no patients lost Snellen lines. The postoperative diopter was within ±0.75 D for all eyes. Significant edema existed above the corneal opacity in one eye and dissipated soon. No eccentric corneal topography or morphological anomaly of the corneal cap or flap was observed. CONCLUSION: The cases demonstrate that SMILE or FS-LASIK is safe and effective to treat myopic astigmatism combined with deep corneal opacity lesions after comprehensive preoperative evaluation and appropriate candidate selection. FS-LASIK combined with LRI is also sufficient for correcting high astigmatism due to corneal scarring.