Laser In Situ Keratomileusis Research Articles

Discriminant prediction equation using an optical biometer for identifying postmyopic laser vision correction eyes.

To create an equation for identifying postmyopic laser vision correction (M-LVC) eyes by using corneal shape parameters in a swept-source optical coherence tomography (SS-OCT) biometer and verify its accuracy. Nagoya Eye Clinic, Nagoya, Japan. Retrospective evaluation of a screening approach. Control participants were selected retrospectively from patients who visited the clinic for cataract surgery or refractive surgery. M-LVC patients were selected retrospectively from patients who visited the clinic for cataract surgery or M-LVC postoperative checkups. The control and post-M-LVC patients with keratometric values between 39 diopters (D) and 43 D were included in the final analysis. Patients were randomly assigned to equation-creation and validation groups in a 2:1 ratio. To discriminate post-M-LVC patients from control participants, multiple logistic regression analysis was performed with the corneal shape parameters from the optical biometer as independent variables. The M-LVC and control groups consisted of 90 eyes from 90 patients and 97 eyes from 97 patients, respectively. The average keratometry (Ave-K) values did not differ significantly between the control and M-LVC groups ( P = .187). The multiple logistic analysis identified the asymmetry component (regression coefficient, 5.357; odds ratio, 212.158) and corneal eccentricity index (regression coefficient, -5.088; odds ratio, 0.006) as explanatory variables. The area under the receiver operating characteristic curve in the predictive equation-creation group was 0.946. The sensitivity and specificity in the validation group were 93.3% and 87.5%, respectively. The M-LVC discriminant prediction equation with the topography-equipped SS-OCT biometer was effective in detecting post-M-LVC eyes with high accuracy.

Reasons for Re-treatment Following Monovision Laser Refractive Surgery.

To assess the incidence and causes for re-treatment following monovision laser refractive surgery in a large data study spanning a decade. The setting for this retrospective comparative study was Care Vision Laser Center, Tel Aviv, Israel. This study included patients aged 36 to 60 years who underwent monovision laser vision correction at the Care Vision Laser Centers, Israel, from January 2012 to December 2022. Demographic, preoperative, and postoperative data were retrieved for analysis. Overall, 3,674 eyes of 1,847 patients were included. Re-treatment was performed in 1.28% (n = 47) of eyes, 0.84% (n = 31) distance-targeted and 0.44% (n = 16) near-targeted. Monovision reversal in near-targeted eyes occurred due to overcorrection (37.5%, n = 6 of 16), despite being on target (25%, n = 4 of 16), insufficient myopia (18.8%, n = 3 of 16), and de novo astigmatism (12.5%, n = 2 of 16). One eye was targeted for near vision due to de novo astigmatism. Re-treatment in distance-targeted eyes was due to myopic undercorrection (45.2%, n = 14 of 31), myopic regression (19.4%, n = 6 of 31), myopic overcorrection (12.9%, n = 4 of 31), hyperopic regression (6.5%, n = 2 of 31), astigmatism undercorrection (6.5%, n = 2 of 31), de novo astigmatism (6.5%, n = 2 of 31), and astigmatism regression (3.2%, n = 1 of 31). Re-treatment was more likely in distance targeted eyes of patients with monovision compared to near-targeted eyes (P = .025) and patients without monovision (P < .001). In monovision laser vision correction, retreatment in the near-targeted eye is rare when the ideal near target (-1.50 to -1.25 diopters) is achieved. However, the distance-targeted eye is more likely to require re-treatment. Surgeons can plan monovision surgery and advise patients accordingly. [J Refract Surg. 2024;40(11):e892-e897.].

Active storage machine can unveil previous LASIK surgery by reproducing ex vivo interface fluid syndrome during eye banking

Active storage machine can unveil previous LASIK surgery by reproducing ex vivo interface fluid syndrome during eye banking

Efficacy of gabapentin and pregabalin for treatment of post refractive surgery pain: a systematic review and meta-analysis.

For ophthalmic patients, eye discomfort is a major problem that requires efficient pain treatment techniques. Pregabalin and gabapentin have surfaced as viable treatments for post-refractive surgery pain. To manage pain after refractive surgery, gabapentin and pregabalin were evaluated in this systematic review and meta-analysis. A thorough search of databases including PubMed, Embase, Cochrane Library, and CINAHL was performed until March 2024. Inclusion criteria were randomized controlled trials assessing pregabalin and/or gabapentin's effectiveness in treating pain post-PRK, LASIK, and LASEK surgeries. Six studies met inclusion criteria, comprising a total of 391 patients undergoing various corneal surgeries. The meta-analysis revealed that pregabalin was significantly more effective than placebo in reducing pain on the first and second postoperative days (SMD day 1: -0.32, 95% CI -0.54, -0.09; SMD day 2: -0.55, 95% CI -0.85, -0.25), while gabapentin showed significant pain reduction on the second day only (SMD day 2: -0.42, 95% CI -0.71, -0.13). Combined analysis for both medications showed significant pain reduction on the first- and second-days post-surgery. No significant increase in adverse events was associated with either medication. Publication bias was minimal except for a slight asymmetry noted on day 1 effectiveness. Pregabalin and gabapentin are effective in reducing postoperative pain following refractive surgeries, with pregabalin showing a greater effect. Both medications are safe, with no significant increase in adverse events. Further research with standardized methodologies and long-term follow-up is recommended to optimize postoperative pain management in ocular surgeries.

Clinical safety and efficacy of elliptical thin-flap LASIK using a low-pulse energy femtosecond laser.

This study assessed the clinical safety and efficacy of elliptical thin-flap LASIK with a low-pulse energy femtosecond laser in 3 thickness subgroups (85, 90, and 100μm). A total of 80 patients who underwent bilateral LASIK surgery at Taiwan between April and September 2019 were retrospectively enrolled. Elliptical corneal flaps with wide temporal hinges and inverted-angled side cuts were created. Target flap thickness was calculated on the basis of residual stromal bed thickness and percent tissue altered. Before flap creation, an optical coherence tomography image for visualization of the precut flap position was obtained with the built-in camera. At postoperative month 1, the overall mean logMAR uncorrected distance visual acuity (UDVA) was - 0.04 ± 0.07 (20/18 Snellen), with 96% of eyes achieving UDVA of 20/20 or better. Postoperative mean manifest spherical equivalent was - 0.37 ± 0.42 D at 1 month. The visual and refractive outcomes in each of the 3 subgroups were similar. The achieved flap thicknesses were found to be highly predictable and consistent in the respective thickness subgroups. Optical coherence tomography-guided thin-flap LASIK performed with the low-pulse energy femtosecond laser was found to be safe with no intraoperative or postoperative complications.

First report of uncommon mycobacteria in post LASIK keratitis: Mycobacterium wolinskyi

Laser assisted in situ keratomileusis (LASIK) surgery is the leading and most performed refractive surgery nowadays. A possible complication of LASIK surgery is infectious keratitis which can lead to disastrous corneal damage and result in permanent loss of vision. LASIK procedures have become increasingly accessible, and the demand for refractive surgery has risen among patients, challenging the medical field to improve the prevention of post-operative infections. Nevertheless, a wide range of pathogens have been described as responsible for post-LASIK keratitis. However, non-tuberculous mycobacterial keratitis remains an infrequent occurrence and is poorly described in the literature. To the best of our knowledge, this is the first ever reported case of post-LASIK keratitis caused by Mycobacterium wolinskyi. We describe the clinical and microbial characteristics, leading to its challenging treatment choice.

Assessing the Role of Artificial Intelligence in the Creation of Patient Educational Videos for Corneal Refractive Surgery.

We aim to assess the ability of artificial intelligence (AI) to generate patient educational videos for various corneal refractive surgeries. Three AI text-to-video platforms (InVideo (San Francisco, CA), ClipTalk (San Francisco, CA), and EasyVid (Los Angeles, CA)) were used to create patient educational videos for laser-assisted in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and small incision lenticule extraction (SMILE), respectively. Videos for LASIK and PRK from the American Academy of Ophthalmology (AAO) and a SMILE video from Zeiss served as controls for each surgery. A three-point grading system (from zero to three, with zero being the worst and three being the best in each category) was used to compare videos in terms of "image accuracy," "script accuracy," "image clarity," and "script alignment." In terms of image accuracy, the control videos outperformed InVideo, EasyVid, and ClipTalk for LASIK (3 versus 0.667 versus 0 versus 0; p<0.005), PRK (3 versus 1 versus 0.33 versus 0; p<0.05 for InVideo, p<0.005 all), and SMILE (3 versus 0.33 versus 0 versus 0.33; p<0.005), respectively. With a few exceptions, all three AI models performed similarly to the control videos in terms of script accuracy, image clarity, and script alignment. In their current state, AI text-to-video generators can produce surgical educational videos for patients with accurate script narration and high image clarity, although these platforms are not yet capable of producing medically accurate images to go along with these scripts. Further improvements in the medical accuracy of these images must be made to make these videos more appropriate for patient consumption.

Comparing Visual Outcomes of KLEx, PRK, and LASIK Procedures in the Military Population.

To assess the 6-month visual and refractive outcomes of keratorefractive lenticule extraction (KLEx) as compared to laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) in a military population at a Joint Warfighter Refractive Surgery Center. Joint Warfighter Refractive Surgery Center (JWRSC), Lackland Air Force Base, San Antonio, TX. Retrospective Study. Patients who underwent either KLEx, PRK, or LASIK between 2019-2022 were included. Anonymized data collected included demographics, pre- and post-operative uncorrected and corrected visual acuity, and manifest refraction. Of the 4,466 treated eyes, 737 (16.5%) underwent the KLEx, 2,801 (62.7%) underwent PRK, and 928 (20.8%) underwent LASIK treatment. In terms of efficacy, there was no statistically significant difference at post-operative month (POM)6 between the percentage of eyes reaching an uncorrected distance visual acuity (UDVA) of 20/20 or better between the three procedures. At POM1 (P < 0.001) and POM3 (P < 0.001), there were a greater number of eyes in the KLEx group that achieved the same or 1 line better of distance visual acuity than the PRK group. The efficacy index of KLEx, PRK, and LASIK at POM6 were 1.09, 1.10, and 0.97, respectively. The safety index for KLEx, PRK, and LASIK at POM6 were 0.96, 1.01, and 0.81, respectively. After the initial recovery period, KLEx demonstrates comparable outcomes in terms of efficacy, safety, and accuracy as compared to LASIK and PRK.

Comparative Analysis of Corneal Wound Healing: Differential Molecular Responses in Tears Following PRK, FS-LASIK, and SMILE Procedures.

In this study, we aimed to analyze the changes in the expression profiles of selected messenger RNAs (mRNAs) and their encoded proteins in the tears of patients undergoing photorefractive keratectomy (PRK), femtosecond-assisted laser in situ keratomileusis (FS-LASIK), and small-incision lenticule extraction (SMILE) procedures. A total of 120 patients were divided into three groups based on the laser vision correction (LVC) procedure: PRK, FS-LASIK, or SMILE. Tear samples were collected preoperatively and at 1, 7, 30, and 180 days postoperatively. The expression levels of selected messenger RNAs (mRNAs) and proteins were analyzed by using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA), respectively. PRK and FS-LASIK elicited significantly stronger biological responses than SMILE. Interleukin-15 (IL-15) expression increased notably in the PRK and FS-LASIK groups, with mRNA levels reaching fold changes of 4.65 ± 0.65 and 4.99 ± 0.28, respectively, on day 1, compared with only 2.09 ± 0.23 in the SMILE group. Vascular endothelial growth factor A (VEGFA) levels were also elevated in the PRK (2.98 ± 0.23 fold change) and FS-LASIK groups (3.45 ± 1.09 fold change) on day 1, while the SMILE group showed minimal fluctuations. The protein concentration analysis based on the ELISA confirmed these trends, with IL-15 levels peaking at 54.2 ± 2.5 pg/mL in the PRK group and 52.8 ± 3.1 pg/mL in the FS-LASIK group, compared with 32.4 ± 1.9 pg/mL in the SMILE group on day 1. Similarly, VEGFA protein concentrations were the highest in the PRK (72.4 ± 4.1 pg/mL) and FS-LASIK patients (69.5 ± 3.8 pg/mL) on day 1 but remained low in the SMILE patients (45.6 ± 2.3 pg/mL). By day 180, gene expression and protein levels in all groups had stabilized, returning to near-preoperative values. PRK and FS-LASIK induced more pronounced molecular and protein-level changes during corneal wound healing than the less invasive SMILE procedure, indicating stronger biological responses. These findings suggest that tailored postoperative care based on the specific procedure could optimize healing and patient outcomes. However, further research with larger sample sizes and longer follow-ups is needed to confirm these observations and develop personalized treatment strategies.

Comparative study of visual and refractive outcomes of laser assisted in situ Keratomileusis versus small incision lenticule extraction versus implantable collamer lens for moderate to high myopia correction

Background Myopia represents a condition of refraction, in which parallel light rays converge in front of the resting eye retina. Aim To compare the laser assisted in situ keratomileusis (LASIK) visual and refractive outcomes versus small incision lenticule extraction (SMILE) versus implantable collamer lens (ICL) while correcting cases having moderate to high myopia. Patients and methods Our research involved 60 eyes having moderate to severe myopia ranging from –3 to –10 dioptres. They divided into three equal groups, group A: through LASIK, group B: through SMILE, and group C: received an ICL. Preoperative uncorrected visual acuity, Corrected distance visual acuity, and Manifest and cycloplgic refraction assessments were accomplished. Results Postoperative uncorrected visual acuity exhibited no significant variation among groups A and B, yet a significant variation was documented among groups A and C as well as among groups B and C P less than 0.001. The postoperative spherical error showed no significant variation among groups A and B nor among groups B and C yet exhibited significant variation among groups A and C P=0.002. Postoperative astigmatism was no significant variation among groups A as well as B, yet a significant variation was documented among groups A and C in addition to between groups B and C. Postoperative spherical equivalent was a significant variation among groups A and C P less than 0.001 and among groups B and C P less than 0.001. Conclusion Visual outcomes were comparable between LASIK, SMILE, and ICL. The three procedures exhibited superior effectiveness, safety, stability, and accuracy in the treatment of moderate and high myopia.

Clinical Performance of an Extended Range of Vision Intraocular Lens After LASIK.

To evaluate the clinical and patient-reported outcomes (PROMs) of cataract surgery with implantation of a wavefront-shaping extended depth of focus (EDOF) intraocular lens (IOL) in eyes with previous laser in situ keratomileusis (LASIK) for myopia correction. This prospective observational study enrolled 50 eyes with previous LASIK from 25 patients (age: 46 to 70 years) who underwent cataract surgery with implantation of the AcrySof IQ Vivity IOL (Alcon Laboratories, Inc). Visual and refractive outcomes were evaluated during a 3-month follow-up. PROMs were evaluated with the Intraocular Lens Satisfaction (IOLSAT; Alcon Vision, LLC) (general satisfaction), Catquest-9SF (difficulty in doing vision-related activities), and Questionnaire for Visual Disturbances (QUVID; Alcon Vision, LLC) (photic phenomena) questionnaires. Mean 3-month postoperative binocular uncorrected distance, intermediate, and near visual acuities were 0.02 ± 0.11, -0.02 ± 0.09, and 0.14 ± 0.13 logarithm of the minimum angle of resolution (logMAR), respectively. Mean binocular distance-corrected intermediate and near visual acuities were 0.05 ± 0.11 and 0.32 ± 0.14 logMAR, respectively. All eyes had a postoperative spherical equivalent within ±0.75 diopters (D). The mean defocus curve showed visual acuity values better than 0.20 logMAR for defocus levels from +0.50 to -1.50 D. Most patients (92.0%) confirmed that they had no vision-related difficulties limiting their normal daily life. Perception of starbursts, halos, glare, hazy vision, blurry vision, and double vision was referred by 24%, 24%, 28%, 28%, 8%, and 4% of patients, respectively. Most of symptoms were described as mild and not or a little bothersome. The wavefront-shaping EDOF IOL evaluated provides efficacious distance, intermediate, and near visual restoration in eyes with previous LASIK, with minimal photic phenomena associated. [J Refract Surg. 2024;40(10):e742-e753.].

Unforeseen challenge: bilateral, spontaneous, symmetrical displacement of toric implantable collamer lens: case report

Introduction: The phakic intraocular lenses represent a significant advancement in refractive correction particularly in patients for whom conventional procedures such as laser in situ keratomileusis (LASIK) are contraindicated. To our knowledge, although studies have extensively documented the occurrence and management of implantable collamer lens (ICL) rotation, spontaneous displacement of the ICL has not yet been documented. In this article, we present an interesting case of bilateral ICL displacement. Patient and Clinical Findings: After undergoing bilateral ICL surgery, the patient presented with blurring of vision the next day. On examination, there was symmetrical bilateral displacement of the ICL despite having implanted the maximum size of this lens. Diagnosis, Intervention, and Outcomes: After discussion and analysis, a bilateral explantation of the ICL was performed. Conclusions: Despite taking into consideration all the essential anterior segment parameters for ICL size calculation, there can still be a possibility of ICL displacement.

Photorefractive Keratectomy: Technical Evolution, Refractive Outcomes, Corneal Wound Healing Response, and Complications.

Photorefractive keratectomy (PRK) was the first excimer laser procedure developed to treat refractive errors. The safety and efficacy of PRK established it as one of the most performed corneal refractive procedures worldwide. With the introduction of laser in situ keratomileusis (LASIK), and more recently keratorefractive lenticule extraction (KLEx) procedures, many corneal surgeons favor these newer corneal procedures as the first choice due to faster visual rehabilitation and less discomfort during the early postoperative period. Importantly, however, PRK remains a viable alternative for most corneal refractive candidates and there are many situations in which PRK remains the refractive procedure of choice. This review addresses the technical evolution of PRK-mechanical epithelial debridement versus alcohol-assisted epithelial removal versus excimer laser-assisted epithelial debridement (transepithelial) PRK-and reports the PRK refractive outcomes compared to other keratorefractive laser procedures. The corneal wound response associated with each PRK technique and the indications, limitations, and complications of PRK are reviewed to aid refractive surgeons to best position PRK in their overall practice. [J Refract Surg. 2024;40(10):e754-e767.].

Visual Improvements After Excimer Laser Multiple Light Redirection in Eyes With Central Visual Loss From Macular Degeneration and Geographic Atrophy: First Report of Cases

Purpose To analyze outcomes after multiple light redirection (MLR) by photoablation of a small paracentral portion of Bowman's layer in each corneal quadrant using standard myopic laser in situ keratomileusis (LASIK) software with non-customized fenestrated MLR corneal light shields (Excimer-MLR) without postoperative visual training or magnification in pseudophakic eyes with central visual loss from age-related macular degeneration (AMD) with geographic atrophy (GA). Methods Retrospective analysis of two cases. Results Outcomes after Excimer-MLR in the worse-seeing eyes of an 86-year-old and a 65-year-old pseudophakic man with AMD and GA revealed corrected distance/near visual acuity gains of 6.0/6.0 and 11.8/10.0 lines within 12 days and 5.0/5.0 and 12.2/9.8 lines at 9 months, respectively, with improved Amsler grids, no distance or near glasses change, no complications, and no adverse events related to Excimer-MLR. Contrast sensitivity and stereopsis, measured in case 2, improved postoperatively. Conclusions This first report showed that Excimer-MLR safely produced large improvements in visual function up to 9 months postoperatively in two eyes with central visual loss from AMD. [ Journal of Refractive Surgery Case Reports. 2024;4(4):e29–e35.]

Updating the no-history method in intraocular lens power calculation after myopic laser vision correction.

To describe the Shammas-Cooke formula, an updated no-history (NH) formula for IOL calculation in eyes with prior myopic laser vision correction (M-LVC), and to compare the results with the Shammas PL, Haigis-L, and Barrett True-K NH formulas. Bascom Palmer Eye Institute (BPEI), The Lennar Foundation Medical Center, University of Miami, Miami, Florida; Dean A. McGee Eye Institute (DMEI), University of Oklahoma, Oklahoma City, Oklahoma; and private practice, Lynwood, California, and St Joseph, Michigan. Retrospective observational study. We analyzed 2 large series of cataractous eyes with prior M-LVC. The training set (BPEI series of 330 eyes) was used to derive the new corneal power conversion equation to be used in the new Shammas-Cooke formula and the testing set (165 eyes of 165 patients in the DMEI series) to compare the updated formula with 3 other M-LVC NH formulas on the ASCRS calculator: Shammas PL, Haigis-L, and Barrett True-K NH. Mean prediction error was 0.09 ± 0.56 diopters (D), -0.44 ± 0.61 D, -0.47 ± 0.59 D, and -0.18 ± 0.56 D and the mean absolute error was 0.43 D, 0.60 D, 0.61 D, and 0.45 D for the Shammas-Cooke, Shammas PL, Haigis-L, and Barrett True-K NH, respectively. The percentage of eyes within ±0.50 D was 66.7% vs 47.9%, 48.5%, and 65.5%, respectively. The Shammas-Cooke formula performed better than the Shammas PL and Haigis-L (P < .001 for both) and as well as the Barrett True-K NH formula (P = .923).

Laser-Assisted In Situ Keratomileusis in Flat, Normal, and Steep Corneas.

To compare laser-assisted in situ keratomileusis (LASIK) outcomes in patients with different corneal curvatures. This is a retrospective comparative chart review. Patients included in this study underwent wavefront-optimized myopic LASIK between January 2013 and December 2022 at Care-Vision Laser Center, Tel-Aviv, Israel. Patients were divided into 3 groups based on the steepness of the cornea (steep keratometry) (flat: <42 diopters [D], normal: 42-46 D, and steep: >46 D). Case-by-case matching was performed to verify that baseline parameters (age, preoperative visual acuity, and refractive error) were similar between groups. Primary outcome measures were postoperative corrected/uncorrected distance visual acuity, efficacy index, safety index, spherical equivalence, and astigmatism. After matching, 300 eyes were included in each group, which were similar in baseline parameters. There were no significant postoperative differences between flat, normal, and steep corneas regarding safety index (1.01 vs. 1.02 vs. 1.01, P = 0.95), efficacy index (1.03 vs. 1.02 vs. 1.02, P = 0.94), logarithm of the minimum angle of resolution corrected distance visual acuity (0.01 vs. 0.01 vs. 0.01, P = 0.17), logarithm of the minimum angle of resolution uncorrected distance visual acuity (0.02 vs. 0.03 vs. 0.02, P = 0.65), proportion of patients with spherical equivalence within 0.50 D (73.0% vs. 73.7% vs. 69.3%, P = 0.45) or 1.00 D (93.3% vs. 94.7% vs. 91.7%, P = 0.34) of the target, and proportion of patients with astigmatism within 0.50 D (86.7% vs. 82.3% vs. 80.3%, P = 0.11) or 1.00 D (98.7% vs. 98.7% vs. 99.0%, P = 0.91) of the target. Longer term follow-up of a smaller set of patients revealed similar results. No significant differences were found between flat, normal, and steep corneas following wavefront-optimized myopic LASIK. Thus, this procedure may be safely and effectively performed across a wide range of corneal curvatures.

Comparing clinical outcomes of trifocal intraocular lens in patients with and without prior history of laser in situ keratomileusis for myopia

BackgroundTo compare clinical outcomes of trifocal intraocular lens in patients with and without prior history of laser in situ keratomileusis (LASIK).MethodsA retrospective study included patients who underwent bilateral cataract surgery and PanOptix trifocal intraocular lens (IOLs) implantation. Patients were grouped: Group A for patients with history of LASIK and Group B for patients without history of LASIK. Postoperative outcome measures comprised distance, intermediate, and near visual acuity, manifest refraction, defocus curve, contrast sensitivity, visual quality, patient satisfaction, and the rate of spectacle independence.ResultsA total of 288 eyes (144 patients) were included: 132 eyes in Group A and 156 eyes in Group B. At 6 months post-surgery, patients of both groups achieved a continuous satisfying visual acuity from 33 cm to distance. 73% of eyes in Group A and 75% of eyes in Group B were within ± 0.50 D of emmetropia (P > 0.05). The percentages of eyes within ± 1.00 D of emmetropia were 98% for Group A and 96% for Group B (P > 0.05). The total scores of satisfaction were 52.58 ± 3.46 for Group A and 53.23 ± 3.46 for Group B (P > 0.05). Most of patients (98% for Group A, 99% for Group B) were able to be spectacle independence for daily living. 53% of patients in Group A and 51% in Group B experiencd mild to moderate negative visual symptoms, which made it a little or moderate difficult to drive at night.ConclusionsCataract patients with and without history of LASIK could safely undergo implantation of the PanOptix IOLs, which results in precise refractive outcomes and satisfactory visual acuity. Although contrast sensitivity decreased and some negative visual symptoms were observed, patients’ satisfaction was generally high due to the high rate of spectacles independence. There were no statistically significant differences between the study groups.

Factors Defining Density of Retinal Macrophage-like Cells Displayed with Optical Coherence Tomography.

To study the factors which define the density of MLC of the inner retinal surface in healthy eyes. Healthy individuals, including candidates for LASIK surgery, and post-LASIK patients were included. MLC density was calculated using structural en face projections of OCT angiography scans. The status of the vitreoretinal interface was assessed as the distance from the inner limiting membrane to the posterior hyaloid membrane on cross-sectional scans and as the area of tight posterior vitreous adhesion on en face projections. The correlation between MLC density and various demographic and anatomical parameters, including the status of the vitreoretinal interface was calculated. Fifty-four healthy individuals, 30 post-LASIK patients all without posterior vitreous detachment (PVD) as well as 20 patients with partial PVD were included. MLC density showed a statistically significant correlation with axial length, refractive error, age, subfoveal choroidal thickness, and the status of the vitreoretinal interface (p<0.05) in eyes without PVD. In multiple regression analysis the axial length was the main parameter independently correlated with MLC density (p=0.025). The status of the vitreoretinal interface had a statistically significant correlation with the axial length (p<0.001). Partial PVD was associated with almost complete loss of MLC (p<0.001). The status of the vitreoretinal interface is a characteristic directly defining the density of retinal MLC in healthy eyes. However, axial length appears to be a key anatomical parameter which correlates with MLC density due to its effects on the adhesion of the posterior hyaloid membrane to the retinal surface.

TRPV1 corneal neuralgia mutation: Enhanced pH response, bradykinin sensitization, and capsaicin desensitization

The factors that contribute to pain after nerve injury remain incompletely understood. Laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) are common surgical techniques to correct refractive errors. After LASIK or PRK, a subset of patients suffers intense and persistent pain, of unknown origin, described by patients as feeling like shards of glass in their eye. Here, we evaluated a TRPV1 variant, p.V527M, found in a 49-y-old woman who developed corneal pain after LASIK and subsequent PRK enhancement, reporting an Ocular Surface Disease Index score of 100. Using patch-clamp and Ca2+ imaging, we found that the V527M mutation enhances the response to acidic pH. Increasing proton concentration induced a stronger leftward shift in the activation curve of V527M compared to WT, resulting in channel activity of the mutant in acidic pH at more physiological membrane potentials. Finally, comparing the responses to consecutive applications of different agonists, we found in V527M channels a reduced capsaicin-induced desensitization and increased sensitization by the arachidonic acid metabolite 12-hydroxyeicosatetraenoic acid (12-HETE). We hypothesize that the increased response in V527M channels to protons and enhanced sensitization by 12-HETE, two inflammatory mediators released in the cornea after tissue damage, may contribute to the pathogenesis of corneal neuralgia after refractive surgery.

Low Contrast Acuity Outcomes After SMILE and LASIK.

To compare early visual quality of small incision lenticule extraction (SMILE) versus laser in situ keratomileusis (LASIK) in terms of low contrast acuity. A secondary analysis was performed using a harmonized dataset derived from two completed prospective cohort studies on active-duty military service members undergoing either SMILE (n = 37), wavefront-guided (WFG) LASIK (n = 51), or wavefront-optimized (WFO) LASIK (n = 56). Night vision and photopic and mesopic low contrast visual acuity (LCVA) up to 3 months postoperatively were compared between groups. Compared to SMILE-treated eyes, WFG LASIK-treated eyes had significantly better night vision and photopic LCVA at 1 month postoperatively (beta = -0.039, P = .016; beta = -0.043, P = .007, respectively). WFO LASIK-treated eyes had significantly better photopic LCVA at 1 month postoperatively (beta = -0.039, P = .012) but had worse mesopic LCVA at 3 months postoperatively (beta = 0.033, P = .015) versus SMILE-treated eyes. SMILE and LASIK, on either a WFG or WFO laser platform, yielded excellent outcomes, but LCVA seemed to recover quicker following LASIK compared to SMILE. [J Refract Surg. 2024;40(9):e667-e671.].