12-Month Outcomes of Small Incision Lenticule Extraction With Proper Head Positioning but No Reference Marking for the Correction of Astigmatism.

PURPOSE: To investigate the 12-month outcomes of small incision lenticule extraction (SMILE) with proper head positioning but no reference marking for correcting astigmatism. METHODS: This was a retrospective cohort study of 3,541 patients (5,953 eyes) who underwent SMILE between July 2010 and April 2021. Patient positioning on the treatment bed was meticulously done in every patient to avoid face turn, head tilt, and chin-up or chin-down posture. The corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), manifest refraction, astigmatic outcomes, and adverse events were evaluated at 1, 3, and 12 months postoperatively. RESULTS: The mean preoperative manifest spherical equivalent and manifest cylinder were -5.15 ± 2.24 diopters (D) (range: -0.13 to -12.88 D) and -1.00 ± 0.77 D (range: -0.25 and -6.00 D), respectively. Of all eyes, 88.4% and 98.6% had the spherical equivalent within ±0.50 and ±1.00 D of emmetropia at 12 months. The percentage of eyes with UDVA of 20/20 or better was 92.5%. Six eyes (0.1%) lost two or more lines of CDVA at the 12-month visit. The predictability of cylinder correction was excellent, with 88.1% within ±0.50 D and 98.9% within ± 1.00 D of astigmatism correction at 12 months. The mean correction index (CI) at 12 months was 1.09 ± 0.45 (range: 0.17 to 4.99), indicating a slight astigmatism overcorrection. The high cylinder group tended to have undercorrection with greater residual astigmatism, whereas the low cylinder group was likely to have overcorrection with lesser residual astigmatism (P < .001). No serious adverse events were observed. CONCLUSIONS: SMILE with proper head positioning but no reference marking produces safe, efficient, predictable, and stable outcomes for astigmatism correction over a 12-month period. [J Refract Surg. 2023;39(10):683-692.].

Epstein-Barr Virus Keratouveitis-Induced Malignant Glaucoma After Penetrating Keratoplasty: A Case Report and Literature Review.

PURPOSE: To report a case of Epstein-Barr virus (EBV) keratouveitis-induced malignant glaucoma after repeat penetrating keratoplasty (PK). METHODS: Retrospective review of the patient's medical records and review of literature on EBV corneal endotheliitis and/or anterior uveitis. RESULTS: A 78-year-old Thai female patient presented with a markedly edematous corneal graft, dense pigmented keratic precipitates, fibrinous anterior chamber reaction, uniformly flat anterior chamber, and ocular hypertension of 55 mmHg in the left eye on the first day after the third PK. An aqueous tap for polymerase chain reaction analysis was positive for EBV DNA but negative for other herpesviruses. The patient was diagnosed with EBV endotheliitis and anterior uveitis-induced malignant glaucoma; and successfully treated with oral valacyclovir and topical 2% ganciclovir eye drops. CONCLUSIONS: EBV endotheliitis and anterior uveitis can induce malignant glaucoma following PK. A high index of suspicion is required when a patient has a history of unexplained multiple graft rejections.

Impact of gender mismatch on corneal graft rejection and rejection-related graft failure in repeat penetrating keratoplasty.

PURPOSE: To explore the impact of gender mismatch on corneal allograft rejection and rejection-related graft failure in patients with repeat penetrating keratoplasty (PK). METHODS: A retrospective cohort was conducted at Ramathibodi Hospital, Bangkok, Thailand. Patients with repeat PK and follow-up period of at least 6 months were recruited. Demographic data, pre-operative ocular findings and donor information were collected. Patients were divided into 2 groups according to gender mismatch between donor and recipient (male to female vs others). Survival analysis was performed using the Kaplan-Meier method. The association between risk factors and the outcomes of graft rejection and rejection-related graft failure were analyzed using Cox proportional hazards regression. RESULTS: Of 68 patients with repeat PK, 26 patients (38.2%) were gender mismatched. There was no difference in 3-year rejection-free survival and graft survival between patients with gender mismatch and others (p = 0.698 and p = 0.402, respectively). Younger recipients (< 40 years) showed a significantly higher rejection rate compared to older recipients (hazard ratio; HR = 3.14, 95% confidence interval; CI 1.15 to 8.58), while patients with multiple PK (> 2 times) were found to be significantly associated with higher rejection-related graft failure compared to patients with 2 times or less PK (HR = 2.72, 95% CI 1.03 to 7.21). After multivariate analysis, only younger recipients demonstrated a statistical significance on graft rejection (adjusted HR = 2.86, 95% CI 1.04 to 7.84). CONCLUSIONS: Gender mismatch might not impact corneal graft rejection or rejection-related graft failure in patients with repeat PK. Younger age was found to be a strong factor associated with graft rejection. Gender matching might not be compulsory for repeat PK.

Assessing the Risk Factors For Diagnosed Symptomatic Dry Eye Using a Smartphone App: Cross-sectional Study.

BACKGROUND: Dry eye (DE) is a chronic inflammatory disease of the ocular surface of the eye that affects millions of people throughout the world. Smartphone use as an effective health care tool has grown exponentially. The "Dry eye or not?" app was created to evaluate the prevalence of symptomatic DE, screen for its occurrence, and provide feedback to users with symptomatic DE throughout Thailand. OBJECTIVE: The purpose of this study was to compare the prevalence of symptomatic dry eye (DE), blink rate, maximum blink interval (MBI), and best spectacle-corrected visual acuity (BSCVA) between people with and without symptomatic DE and to identify risk factors for symptomatic DE in Thailand. METHODS: This cross-sectional study sourced data from the "Dry eye or not?" smartphone app between November 2019 and July 2020. This app collected demographic data, Ocular Surface Disease Index (OSDI) score, blink rate, MBI, BSCVA, and visual display terminal (VDT) use data. The criterion for symptomatic DE was OSDI score ≥13. RESULTS: The prevalence of symptomatic DE among individuals using this smartphone app in Thailand was 85.8% (8131/9482), with the Northeastern region of Thailand having the highest prevalence, followed by the Northern region. Worse BSCVA (median 0.20, IQR 0.40; P=.02), increased blink rate (median 18, IQR 16; P<.001), reduced MBI (median 8.90, IQR 10.80; P<.001), female sex (adjusted OR 1.83; 95% CI 1.59-2.09; P<.001), more than 6 hours of VDT use (adjusted OR 1.59; 95% CI 1.15-2.19; P=.004), and lower than bachelor's degree (adjusted OR 1.30; 95% CI 1.03-1.64; P=.02) were significantly associated with symptomatic DE. An age over 50 years (adjusted OR 0.77; 95% CI 0.60-0.99) was significantly less associated with symptomatic DE (P=.04). CONCLUSIONS: This smartphone DE app showed that the prevalence of symptomatic DE in Thailand was 85.8%. Signs and risk factors could be also evaluated with this smartphone DE app. Screening for DE by this app may allow for the development of strategic plans for health care systems in Thailand.

Compliance with Lid Hygiene in Patients with Meibomian Gland Dysfunction.

Purpose: To evaluate the level and predictor of compliance with lid hygiene of the patients with meibomian gland dysfunction (MGD) by a specially designed and validated questionnaire. Patients and Methods: A cross-sectional, descriptive study was conducted among patients with symptomatic meibomian gland dysfunction visiting at Ramathibodi Hospital from April 2019 to December 2020. Dry eye symptom, fluorescein tear breakup time (TBUT), ocular surface staining, lid morphology, meibum quality, and meibum expressibility were evaluated. All patients were instructed to perform lid hygiene two times daily. Eight weeks after receiving the instruction, the patients were asked to complete a newly developed seven-item questionnaire to assess compliance. The associated factors limiting treatment adherence were evaluated. Proper statistical analyses were used to determine the relationships between compliance and non-compliance and a group of relevant baseline variables. P < 0.05 was considered to be statistically significant. Results: A total of 77 patients were recruited into the study. Sixty-three patients (81.8%) were female. The mean age was 66.71 ± 8.17 years old (42-87 years). Good compliance with lid hygiene was reported by 42 patients (54.6%). Patient demographic factors or the number of concurrent systemic or ophthalmic drugs were not significantly different between the compliance and non-compliance groups. Some clinical signs, including the higher scores of meibomian gland expressibility and moderate to severe ocular surface staining, were significantly positively associated with lid hygiene compliance (χ 2 = 10.13, P = 0.001 and χ 2 = 10.48, P = 0.001, respectively). A lack of time was the most notable reason for non-compliance. Conclusion: Approximately half of the patients with symptomatic MGD had good compliance with lid hygiene by the specific questionnaire. Appropriate patient education and optimization methods of lid hygiene may promote patient compliance.

Agreement of implantable collamer lens sizes using parameters from different devices.

Objective: To assess agreement and repeatability of white-to-white (WTW) and anterior chamber depth (ACD), and agreement of implantable collamer lens (ICL) size using these measurements from different devices. Methods and analysis: A retrospective review of 83 eyes with ICL implantation (42 patients) was conducted. The agreement of WTW (measured with WaveLight Topolyzer and Orbscan IIz) and ACD (measured with WaveLight Oculyzer and Orbscan IIz) was analysed. Correlation of ICL sizes and difference of eyes with unacceptable vaults between two data sets (WaveLight platform; Topolyzer and Oculyzer and Orbscan IIz) were assessed. Results: Average WTW measured by Orbscan IIz and Topolyzer demonstrated good agreement (Ρ 0.884) with low systematic bias (-0.03±0.1 mm) and narrow 95% limits of agreement (LoA) of -0.28 to 0.22. Average ACD measured by Orbscan IIz and Oculyzer also showed good agreement (Ρ 0.903) with low systematic bias (-0.04±0.1 mm) and relatively narrow 95% LoA (0.2 to 0.12). ICL size selected according to two data sets showed moderate to strong level of agreement (Kappa=0.81). There was a statistically significant difference (p<0.001) in the proportion of eyes with unacceptable postoperative vaults when using the Wavelight platform data set (five eyes, 6.02%) and the Orbscan IIz data set (12 eyes, 14.46%). Conclusion: Although the agreement of WTW and ACD between devices was good, there was a significant difference in proportion of eyes with unacceptable postoperative vaults when using two data sets. Therefore, Topolyzer and Oculyzer might not be suitable for operating interchangeably with Orbscan IIz for ICL size selection.

Incidence and Risk Factors of Corneal Endothelial Failure after Phacoemulsification in Patients with Fuchs Endothelial Corneal Dystrophy: A 13-Year Retrospective Cohort.

OBJECTIVE: To evaluate the incidence of corneal endothelial failure (CEF) and determine the risk factors of developing CEF after phacoemulsification in patients with Fuchs endothelial corneal dystrophy (FECD). METHODS: A retrospective chart review of 2873 patients who underwent phacoemulsification with intraocular lens (IOL) implantation was conducted at Ramathibodi Hospital, Bangkok, Thailand from January 2007 to December 2019. Patient baseline characteristics, underlying diseases, levels of nuclear cataract, pre-operative specular microscopic parameters, intraoperative information (cumulative dissipated energy [CDE], mode of phacoemulsification, and complications), and occurrence of CEF were collected. Data were analyzed using Kaplan-Meier (KM) method and Cox proportional hazard model. RESULTS: Ninety-four patients diagnosed with FECD at follow-up time of more than 6 months were included for analysis. Mean age was 70.3 ± 7.7 years with female predominance (81.91%). Median follow-up time was 3.2 years. Nine (9.57%) patients developed CEF during follow-up period. The overall incidence rate of CEF after phacoemulsification was 26 per 1000 person years (95% confidence interval [CI]; 14 to 49 per 1000 person years). Only intraoperative complications showed significant association with CEF at hazard ratio (HR) of 6.03 (95% CI 1.50 to 26.50). No significant association was found among age, gender, underlying diseases, level of nuclear sclerosis and pre-operative specular microscopic parameters. CONCLUSION: Intraoperative complications should be considered as an important risk factor for developing post-operative CEF in FECD patients. Apart from assessing pre-operative parameters, surgeons should also consider the possibility of and try to avoid any intra-operative complications, which could potentially result in CEF after phacoemulsification for each individual patient.

Predicting factors and prediction model for discriminating between fungal infection and bacterial infection in severe microbial keratitis.

A retrospective medical record review including 344 patients who were admitted with severe microbial keratitis at Ramathibodi Hospital, Bangkok, Thailand, from January 2010 to December 2016 was conducted. Causative organisms were identified in 136 patients based on positive culture results, pathological reports and confocal microscopy findings. Eighty-six eyes (63.24%) were bacterial keratitis, while 50 eyes (36.76%) were fungal keratitis. Demographics, clinical history, and clinical findings from slit-lamp examinations were collected. We found statistically significant differences between fungal and bacterial infections in terms of age, occupation, contact lens use, underlying ocular surface diseases, previous ocular surgery, referral status, and duration since onset (p < 0.05). For clinical features, depth of lesions, feathery edge, satellite lesions and presence of endothelial plaque were significantly higher in fungal infection compared to bacterial infection with odds ratios of 2.97 (95%CI 1.43-6.15), 3.92 (95%CI 1.62-9.45), 6.27 (95%CI 2.26-17.41) and 8.00 (95%CI 3.45-18.59), respectively. After multivariate analysis of all factors, there were 7 factors including occupation, history of trauma, duration since onset, depth of lesion, satellite lesions, endothelial plaque and stromal melting that showed statistical significance at p < 0.05. We constructed the prediction model based on these 7 identified factors. The model demonstrated a favorable receiver operating characteristic curve (ROC = 0.79, 95%CI 0.72-0.86) with correct classification, sensitivity and specificity of 81.48%, 70% and 88.24%, respectively at the optimal cut-off point. In conclusion, we propose potential prediction factors and prediction model as an adjunctive tool for clinicians to rapidly differentiate fungal infection from bacterial infection in severe microbial keratitis patients.

Factors Contributing to Long-Term Severe Visual Impairment in Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis.

Purpose. To study the correlation between demographics and clinical variables and long-term severe visual impairment in patients with Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN). Methods. A retrospective chart review of SJS/TEN patients between 2004 and 2014 was conducted. Demographics, causative agents, ocular manifestations, and visual outcomes were collected. The data were analyzed using a multivariate logistic regression model. Results. Of the 89 patients including SJS (65, 73.03%), TEN (15, 16.85%), and SJS-TEN overlap (9, 10.11%), 55 were female. The mean age was 41.58 ± 19.17 years. The most common identified agents were medications. Among these groups, antibiotics were the most prevalent (47.19%). Three patients (3.7%) had unknown etiology. Antibiotics and nonpharmaceutical triggers were significantly associated with long-term severe visual impairment (odds ratio 4.32; P = 0.015 and 7.20; P = 0.037, resp.). There was a significant negative relationship between HIV infection and long-term severe visual impairment (P = 0.021). Among all chronic ocular complications, only corneal neovascularization significantly correlated with severe visual impairment (P = 0.001). Conclusions. SJS/TEN patients caused by nonpharmaceutical triggers or antibiotics have an increased risk of developing long-term severe visual impairment from corneal neovascularization. HIV infection might be a protective factor against long-term poor visual outcomes.

Outcomes of descemet stripping automated endothelial keratoplasty using imported donor corneas.

BACKGROUND: The lack of development of local donor tissue acquisition in several regions of the world has resulted in the necessity of performing keratoplasty with imported donor corneas. The greatest concern about the use of donor corneas supplied by foreign eye banks is the effect of the increased donor death-to-operation time which inevitably occurs during the tissue recovery, tissue processing, and tissue transfer between the countries. The purpose of this study was to report the outcomes of descemet stripping automated endothelial keratoplasty (DSAEK) using imported donor corneas. METHODS: This retrospective, non-comparative case series investigated the outcomes of the 102 consecutive DSAEK procedures using imported donor corneas performed at a single university-based hospital between August 2006-2014. The main outcome measures were postoperative best-corrected visual acuity (BCVA), endothelial cell density (ECD), and complications. RESULTS: The mean death-to-operation time was 9.52 ± 1.48 days (range, 8-13). The mean preoperative ECD was 2761 ± 285 cells/mm2. Fuchs' endothelial dystrophy was the predominant indication for grafting. The mean follow-up duration was 65.3 months. Ninety-three eyes had improved vision postoperatively (91.18%). BCVA unchanged in 3 eyes due to preexisting macular scar and advanced glaucoma. Primary graft failure occurred in 6 eyes (5.88%). Of the 93 eyes with improved BCVA, 100% had their best corrected vision within the first 1 year. The mean ECD at 6, 12, 24, 36, and 60 months after surgery was 1762 ± 294 cells/mm2, 1681 ± 284 cells/mm2, 1579 ± 209 cells/mm2, 1389 ± 273 cells/mm2, and 1251 ± 264 cells/mm2 respectively. The mean ECD loss at 6 months, 1 year, 2 years, 3 years, and 5 years after surgery was 36.2%, 39.1%, 42.8%, 49.7%, and 54.7% respectively. The most common complication was graft detachment/dislocation (10.78%). There were no cases of any postoperative infection. CONCLUSIONS: DSAEK with imported donor corneas provides rapid and good visual rehabilitation. The percentages of endothelial cell loss were comparable to those achieved in Western series using domestic corneas in which fresher tissues were available for transplantation.

Undiluted Serum Eye Drops for the Treatment of Persistent Corneal Epitheilal Defects.

Several studies found that 50-100% serum eye drops provided greater benefits without inducing detrimental effects on the corneal epithelial healing. This study assessed the efficacy of undiluted serum eye drops for the treatment of persistent corneal epithelial defects (PED). A total of 109 eyes received 100% serum eye drops for PED were recruited into this study. The data were compared with an historical control group of 79 eyes with PED who received conventional treatments from 2006-2011 at the same institution. Main outcome measures were complete healing of PED and incidence of adverse events. No significant difference in demographics between the 2 groups was noted. The success rate of the treatment and control groups were 87.16% (95% CI 0.79-0.93) and 69.62% (95% CI 0.59-0.80) (P = 0.001), respectively. The median time to complete epithelialization was 14 days (95% CI 12-21) in the treatment group and 28 days (95% CI 21-59) in the control group (P = 0.001). Serum treatment, primary diagnosis of non-limbal stem cell deficiency etiology, and prior contact lens wear significantly correlated with the corneal re-epithelialization. There were no serious side effects encountered during the study period. In conclusion, undiluted serum therapy is effective and safe for treating PED.

Agreement between clinical history method, Orbscan IIz, and Pentacam in estimating corneal power after myopic excimer laser surgery.

The purpose of this study was to investigate the agreement between the clinical history method (CHM), Orbscan IIz, and Pentacam in estimating corneal power after myopic excimer laser surgery. Fifty five patients who had myopic LASIK/PRK were recruited into this study. One eye of each patient was randomly selected by a computer-generated process. At 6 months after surgery, postoperative corneal power was calculated from the CHM, Orbscan IIz total optical power at the 3.0 and 4.0 mm zones, and Pentacam equivalent keratometric readings (EKRs) at 3.0, 4.0, and 4.5 mm. Statistical analyses included multilevel models, Pearson's correlation test, and Bland-Altman plots. The Orbscan IIz 3.0-mm and 4.0 mm total optical power, and Pentacam 3.0-mm, 4.0-mm, and 4.5-mm EKR values had strong linear positive correlations with the CHM values (r = 0.90-0.94, P = <0.001, for all comparisons, Pearson's correlation). However, only Pentacam 3.0-mm EKR was not statistically different from CHM (P = 0.17, multilevel models). The mean 3.0- and 4.0-mm total optical powers of the Orbscan IIz were significantly flatter than the values derived from CHM, while the average EKRs of the Pentacam at 4.0 and 4.5 mm were significantly steeper. The mean Orbscan IIz 3.0-mm total optical power was the lowest keratometric reading compared to the other 5 values. Large 95% LoA was observed between each of these values, particularly EKRs, and those obtained with the CHM. The width of the 95% LoA was narrowest for Orbscan IIz 3.0-mm total optical power. In conclusion, the keratometric values extracted from these 3 methods were disparate, either because of a statistically significant difference in the mean values or moderate agreement between them. Therefore, they are not considered equivalent and cannot be used interchangeably.

Medium-term outcomes of boston type 1 keratoprosthesis implantation in Bangkok, Thailand.

PURPOSE: The aim of this study was to investigate the medium-term outcomes after Boston type 1 keratoprosthesis surgery in patients with poor prognosis for standard keratoplasty. METHODS: A prospective study of a case series was conducted at a university-based referral center from 2006 to 2013. Forty-two eyes of 40 patients with a minimum follow-up of 4 years were recruited. The main outcome measures included best spectacle-corrected visual acuity (BSCVA), keratoprosthesis retention, and complications. RESULTS: The mean follow-up was 64.9 ± 15.2 months (range, 48-88 months). At 1 week, 90.5% had an improvement in BSCVA by ≥2 lines compared with that in preoperative BSCVA. The best-ever vision was reached by the end of 6 months. Nevertheless, 39.5% (15/38) could not maintain the improved vision. The major etiology of visual deterioration after initial gains was glaucoma (60%). The initial keratoprosthesis retention rate was 80.9%, corresponding to a failure rate of 4 per 100 eye-years or 0.04/eye-year. Autoimmune diagnosis was the independent risk factor for keratoprosthesis failure (hazard ratio, 5.68; 95% confidence interval, 1.41-22.85; P = 0.014). The common postoperative complications were glaucoma, retroprosthetic membrane, corneal melting, infectious keratitis, and endophthalmitis. CONCLUSIONS: Boston type 1 keratoprosthesis is an alternative for patients who are not candidates for corneal transplants. However, there was a trend toward visual loss over time most commonly because of progressive glaucoma. Therefore, appropriate patient selection, lifelong follow-up, and early aggressive treatment of complications are recommended.

Effects of sodium hyaluronate on wavefront aberrations in dry eye patients.

PURPOSE: To investigate the effects of a single instillation of hypotonic 0.18% sodium hyaluronate artificial tears on wavefront aberrations in dry eye patients. METHODS: Fifty patients with dry eye were recruited into this single-center, prospective, double-masked, randomized controlled trial. Patients were randomly assigned to receive one drop of preservative-free, hypotonic 0.18% sodium hyaluronate (treatment) in one eye and one drop of sterile 0.9% sodium chloride solution (control) in the other eye. Ocular aberrations evaluated by a Hartmann-Shack aberrometer and severity of dry eye symptoms graded by a questionnaire (at baseline, 1, 10, 30, 60, and 120 minutes after instillation) were the main outcome measures. RESULTS: After a single instillation of one drop of the allocated eye drops, there were no statistically significant differences between the treatment and control groups in total higher-order aberrations, coma, and spherical aberrations during the study period (p = 0.40, 0.57, and 0.16, respectively). Although a statistically significant (p = 0.04) decrease from baseline in spherical aberrations was noted in the treatment group at 1 minute following instillation, it gradually increased back to baseline values at later time points. A statistically significant diminishment of dry eye symptoms compared with the placebo was reported at all time points by the treatment group (p < 0.001). CONCLUSIONS: A single instillation of hypotonic 0.18% sodium hyaluronate eye drops is safe and effective in alleviating subjective dry eye symptoms; however, it does not appear to affect higher-order aberrations in moderate to severe dry eye patients.

Topical 100% serum eye drops for treating corneal epithelial defect after ocular surgery.

The purpose of this study was to investigate the efficacy and safety of topical 100% serum eye drops for corneal epithelial defect after ocular surgery. A total of 181 patients who received topical 100% serum therapy for the treatment of corneal epithelial defect following several different types of ocular surgery were recruited into this study. Each patient already failed conventional medical therapy before being prescribed 100% serum eye drops. Slit-lamp biomicroscopic examination with fluorescein staining was performed at baseline and all follow-up visits. The main outcome measures were the rate of complete healing of the corneal epithelial defect and incidence of adverse events. One hundred and seventy-eight eyes (98.34%) received autologous serum eye drops, and 3 (1.66%) received allogeneic serum eye drops. The overall success rate of treating persistent postoperative epithelial defect using 100% serum eye drops was 93.92% (95% CI 0.88-0.98). The median time to complete corneal epithelialization was 4 days (95% CI 4-5). Adverse reactions were observed in 3 patients (1.66%), including sticky sensation with minimal eye discomfort and asymptomatic trace corneal subepithelial infiltration. No serious complications were reported. In conclusion, 100% serum eye drops are effective, safe, and tolerable for treating postoperative corneal epithelial defect following ocular surgeries.

Pythium insidiosum keratitis in contact lens wear: a case report.

PURPOSE: The purpose of this study was to report a case of contact lens-related Pythium insidiosum corneal ulcer. METHODS: The authors conducted an interventional case report. We report the clinical presentations, histopathologic findings, and treatments of a patient with P. insidiosum keratitis associated with contact lens wear. RESULTS: A 22-year-old Thai woman presented to our clinic with a nonresponsive, progressive corneal ulcer of the left eye. Slit lamp examination showed a large central ulcer measuring 5.4 x 5.2 mm with underlying dense stromal infiltrates surrounded by subepithelial and superficial stromal opacity in a reticular pattern along with radial perineural-like infiltrates. Histopathologic examination revealed broad, branched, thin-walled nonparallel hyaline hyphae with rare septates consistent with P. insidiosum. The corneal culture confirmed the diagnosis. The infection recurred after multiple therapeutic penetrating keratoplasties. Enucleation was eventually performed to eradicate the infection. No definite report of contact lens-related P. insidiosum keratitis existed in the literature. CONCLUSION: Pythium keratitis may present with central ulcer and radial keratoneuritis similar to acanthamoeba keratitis. Contact lens wear can be a risk factor for this infection. Increasing awareness, early diagnosis, and intervention may improve the prognosis.

A serum- and feeder-free technique of culturing human corneal epithelial stem cells on amniotic membrane.

PURPOSE: To describe a simple technique of cultivating human corneal epithelial stem cells using an Epilife culture medium under serum- and feeder-free conditions. METHODS: Cadaveric donor limbal corneal epithelial cells were cultured on denuded amniotic membranes using an explant technique that was free of serum and feeder cells in the Epilife medium containing a growth supplement of defined composition. These cells were assessed by phase contrast microscope. The expressions of the proposed corneal epithelial stem cell markers (p63, ATP-binding cassette member 2 (ABCG2), and cytokeratin 15 and 19) and differentiation markers (cytokeratin 3, 12, connexin 43, and p75) were analyzed using reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical staining. RESULTS: Successful cultures were obtained, resulting in a monolayer to double layer cell sheets with a cobblestone-like morphology. RT-PCR and immunocytochemistry disclosed an expression of both putative limbal stem cell (LSC) markers and differentiation-associated markers in the cultured cells. Most of the cultured corneal epithelial cells that were immunopositive for putative LSC markers were smaller, more uniform, and closer to the limbal explant than cells positively stained with differentiation-associated markers. CONCLUSIONS: A serum- and feeder-free culture system using Epilife medium may grow human corneal epithelial equivalents, minimizing the risk of contamination during culture. The technique may also be useful for the clinical application of limbal stem cell culture.

Pathologic findings in postmortem corneas after successful laser in situ keratomileusis.

PURPOSE: To examine the histologic and ultrastructural features of human corneas after successful laser in situ keratomileusis (LASIK). METHODS: Corneas from 48 eyes of 25 postmortem patients were processed for histology and transmission electron microscopy (TEM). The 25 patients had LASIK between 3 months and 7 years prior to death. Evaluation of all 5 layers of the cornea and the LASIK flap interface region was done using routine histology, periodic acid-Schiff (PAS)-stained specimens, toluidine blue-stained thick sections, and TEM. RESULTS: In patients for whom visual acuity was known, the first postoperative day uncorrected visual acuity was 20/15 to 20/30. In patients for whom clinical records were available, the postoperative corneal topography was normal and clinical examination showed a semicircular ring of haze at the wound margin of the LASIK flap. Histologically, the LASIK flap measured, on average, 142.7 microm (range, 100-200). A spectrum of abnormal histopathologic and ultrastructural findings was present in all corneas. Findings at the flap surface included elongated basal epithelial cells, epithelial hyperplasia, thickening and undulations of the epithelial basement membrane (EBM), and undulations of Bowman's layer. Findings in or adjacent to the wound included collagen lamellar disarray; activated keratocytes; quiescent keratocytes with small vacuoles; epithelial ingrowth; eosinophilic deposits; PAS-positive, electron-dense granular material interspersed with randomly ordered collagen fibrils; increased spacing between collagen fibrils; and widely spaced banded collagen. There was no observable correlation between postoperative intervals and the severity or type of pathologic change except for the accumulation the electron-dense granular material. CONCLUSIONS: Permanent pathologic changes were present in all post-LASIK corneas. These changes were most prevalent in the lamellar interface wound. These changes along with other pathologic alterations in post-LASIK corneas may change the functionality of the cornea after LASIK.

Effect of laser in situ keratomileusis on the corneal endothelium.

PURPOSE: To assess the effects of laser in situ keratomileusis (LASIK) on the corneal endothelium. METHODS: In a prospective study, preoperative and 12-month postoperative specular microscopy of the central corneal endothelium and corneal thickness assessment was done in 180 eyes of 105 patients (mean age 31.96 +/- 8.88 years; range 16 to 55 yr) who had LASIK to correct myopia. The central endothelium was analyzed for several parameters including cell density, coefficient of variation, and corneal thickness. Preoperative and postoperative data were compared. RESULTS: The mean preoperative endothelial cell density was 2,547.37 +/- 282.00 cells/mm2, mean coefficient of variation of cell size was 58.33 +/- 11.50%, and mean central corneal thickness was 558.90 +/- 28.42 microm. There was not a statistically significant change in mean endothelial cell density (2,508.24 +/- 289.57 cells/mm2) or mean coefficient of variation (58.61 +/- 9.89%) at 1 year after surgery (P >.05 ). Average endothelial cell loss was 1.54% at 1 year after surgery. Mean central corneal thickness at 12 months postoperatively was 493.24 +/- 52.55 microm (P<.01). CONCLUSION: LASIK did not appear to alter corneal endothelial cell density at 12 months postoperatively.