Double peak axial length measurement signal in cataract patients with epiretinal membrane.

PURPOSE: To evaluate the accuracy of axial length (AL) measurement for intraocular lens (IOL) calculation in patients with cataract and epiretinal membrane (ERM). METHODS: This prospective, cross-sectional study was performed in cataract patients with ERM. All subjects were sent for standard optical biometry, prepared for cataract surgery. Signals of AL measurement were detected as double peaks and recorded as AL1 (first peak), and AL2 (second peak). The IOL power was calculated from AL1 and AL2, and reported as IOL1 and IOL2. The IOL2 was chosen for cataract surgery in all cases. Postoperative predictive errors were compared between IOL1 and IOL2. RESULTS: Thirty-seven eyes from 37 patients were included. Mean AL1 was significantly shorter than AL2 (23.13 ± 1.28 vs. 23.60 ± 1.34 mm, p < 0.001), resulting in higher power of IOL1 than IOL2 (mean difference was 1.53 ± 0.96 diopters, p < 0.001). At 3-months post-operation, twenty-nine eyes (78.4%) (95% CI 62.8%-88.6%) showed refractive error within ± 0.5 diopter and all eyes were within ± 1.0 diopter. Postoperative predictive errors including mean arithmetic error (ME) and mean absolute error (MAE) of IOL2 were significantly lower than those of IOL1 (ME: IOL1 vs. IOL2, -0.94 ± 0.91 vs. 0.08 ± 0.51; MAE: 0.97 ± 0.88 vs. 0.39 ± 0.33 diopter, all p < 0.001). CONCLUSIONS: AL measurement in ERM can be detected as a double peak signal during biometric measurement. The IOL power calculated from the first and second peak signals is significantly different. However, the IOL power derived from the second peak signal provides better refractive outcomes. The results suggest that the second peak signal represents an accurate AL measurement.

Efficacy of Swept-source Optical Coherence Tomography in Axial Length Measurement for Advanced Cataract Patients.

SIGNIFICANCE: A major limitation of standard time-domain optical coherence tomography-based biometers (TD-OCT) is an inability to measure the axial length (AL) in advanced cataract. A new device that uses swept-source optical coherence tomography (SS-OCT) allows better light penetration. Hence, a considerable number of cataract patients who failed AL measurement by TD-OCT can be recovered by SS-OCT. PURPOSE: The purposes of this study were to evaluate the efficacy of an SS-OCT for AL measurement in advanced cataract patients and to identify characteristics of lens opacity that impede the AL measurement. METHODS: Advanced cataract patients who were unable to obtain AL measurement using a standard TD-OCT-based optical biometer (IOLMaster500; Carl Zeiss Meditec, Jena, Germany) were recruited in this study. The AL was remeasured using SS-OCT (IOLMaster700), followed by measurement with immersion ultrasonography (IU). The percentage of patients who achieved AL measurement by SS-OCT was recorded. The AL obtained from SS-OCT was then verified by comparing with the AL derived from IU. The cataract type of each patient was classified according to standard Lens Opacity Classification III score. The association between characteristics of cataract and successful AL measurement by SS-OCT was analyzed. RESULTS: Sixty-four eyes that failed AL measurement from TD-OCT were included. Fifty-six eyes (87.5%) were able to be measured by SS-OCT (95% confidence interval, 77.23 to 93.53%). The AL obtained by SS-OCT showed very high agreement with those derived from IU (intraclass correlation coefficient, 0.99). There was no statistically significant correlation between characteristics of lens opacity and the capability of SS-OCT for AL measurement (P > .05). However, there was a trend toward an inability to measure the AL in cataracts with a high grade of lens opacity. CONCLUSIONS: The efficacy of SS-OCT-based optical biometer was excellent. Of the patients with advanced cataract who failed the AL measurement by TD-OCT, 87.5% could be recovered by SS-OCT. However, there was no specific type of lens opacity associated with a failure of AL measurement using SS-OCT.

Comparison of refractive outcomes using conventional keratometry or total keratometry for IOL power calculation in cataract surgery.

PURPOSE: To compare the refractive outcomes following cataract surgery using conventional keratometry (K) and total keratometry (TK) for intraocular lens (IOL) calculation in the SRK/T, HofferQ, Haigis, and Holladay 1 and 2, as well as Barrett and Barrett TK Universal II formulas. METHODS: Sixty eyes of 60 patients from Siriraj Hospital, Thailand, were prospectively enrolled in this comparative study. Eyes were assessed using a swept-source optical biometer (IOLMaster 700; Carl Zeiss Meditec, Jena, Germany). Posterior keratometry, K, TK, central corneal thickness, anterior chamber depth, lens thickness, axial length, and white-to-white corneal diameter were recorded. Emmetropic IOL power was calculated using K and TK in all formulas. Selected IOL power and predicted refractive outcomes were recorded. Postoperative manifest refraction was measured 3 months postoperatively. Mean absolute errors (MAEs), median absolute errors (MedAEs), and percentage of eyes within ± 0.25, ± 0.50, and ± 1.00 D of predicted refraction were calculated for all formulas in both groups. RESULTS: Mean difference between K and TK was 0.03 D (44.56 ± 1.18 vs. 44.59 ± 1.22 D), showing excellent agreement (ICC = 0.99, all p < 0.001). Emmetropic IOL powers in all formulas for both groups were very similar, with a trend toward lower MAEs and MedAEs for TK when compared with K. The Barrett TK Universal II formula demonstrated the lowest MAEs. Proportion of eyes within ± 0.25, ± 0.50, and ± 1.00 D of predicted refraction were slightly higher in the TK group. CONCLUSIONS: Conventional K and TK for IOL calculation showed strong agreement with a trend toward better refractive outcomes using TK. The same IOL constant can be used for both K and TK.

Epithelial analysis of simple limbal epithelial transplantation in limbal stem cell deficiency by in vivo confocal microscopy and impression cytology.

Simple limbal epithelial transplantation (SLET) is a relatively new treatment for severe limbal stem cell deficiency. Outcomes of treatment are typically determined based on clinical manifestations. In this prospective-multicenter study, we aimed to analyze the epithelial phenotypes of the corneas after SLET using IVCM and IC, and correlated them with clinical findings. Ten eyes of nine patients, who underwent SLET (five autologous SLET and five living-related SLET) were recruited. A set of examinations included slit-lamp biomicroscopy, corneal in vivo confocal microscopy (IVCM), and impression cytology (IC) was performed in all eyes at least twice (≥ 3-month interval) postoperatively. Then, a correlation between findings of the three examinations was analyzed. There were seven eyes with clinical success (no central neovascularization) showed pure corneal epithelial phenotype or mixed corneal-conjunctival phenotypes (mostly cornea) in either IVCM or IC. Three eyes with clinical failure, presented with peripheral and central neovascularization, showed total or predominant conjunctival phenotype in IVCM and sole conjunctival phenotype in IC. From a total of 22 sets of examinations, there was a high correlation between clinical manifestation vs. IC (κ = 0.844, observed agreement = 81.82%) and a substantial correlation between clinical manifestation vs. IVCM (κ = 0.727, observed agreement = 76.19%) and between IVCM versus IC (κ = 0.729, observed agreement = 76.19%). In conclusion, IVCM and IC facilitate determination of epithelial phenotype of the cornea after SLET. There was a substantial to high correlation between IVCM, IC and clinical presentations. Findings observed by IVCM and IC may allow early detection of epithelial alterations in eyes underwent SLET before clinical recognition.

Comparative analysis of long-term results of three epithelial cell transplantation procedures for treating limbal stem cell deficiency.

This study compared the long-term outcome of different epithelial transplantation techniques to treat limbal stem cell deficiency (LSCD). We conducted a retrospective 15-year comparative systematic cohort study of patients with LSCD who underwent either cultivated limbal epithelial transplantation (CLET), simple limbal epithelial transplantation (SLET), or cultivated oral mucosal epithelial transplantation (COMET). We reviewed the demographic data, etiology, LSCD severity, best-corrected visual acuity, surgical outcomes, and complications. A total of 103 eyes of 94 patients (mean age, 45.0 ± 16.4 years) with LSCD were enrolled. The most common cause of LSCD was chemical injury (42.7 %). The median follow-up time was 75 months. The success rates of CLET, SLET, and COMET were 45.5 %, 77.8 %, and 57.8 %, respectively. The 7-year survival rates after CLET, SLET, and COMET were 50.0 %, 72.2 %, and 53.2 %, respectively. Steven-Johnson syndrome (SJS) had a significantly lower survival rate than other causes (p < 0.001), but SLET had a significantly higher survival rate than CLET (p = 0.018) and COMET (p = 0.047). Visual improvement of more than four Snellen lines was achieved in 53.1 % of successful cases and 28.2 % of failed cases. SJS, Schirmer I test <5 mm, and the presence of postoperative recurrent epithelial defects were significant risk factors for a failed surgery. All epithelial transplantation techniques had favorable long-term surgical outcomes. More than half of the patients achieved a stable ocular surface and visual acuity improvement up to 7 years postoperatively. SLET tends to have a better surgical outcome than CLET and COMET, especially in patients with SJS.

Effects of intraocular pressure change on intraocular lens power calculation in primary open-angle glaucoma and ocular hypertension.

This study aimed to assess the effect of intraocular pressure (IOP) changes on biometry and intraocular lens (IOL) power calculation in patients diagnosed with primary open-angle glaucoma (POAG) and ocular hypertension (OHT). This prospective non-randomized cohort study enrolled patients with diagnosed POAG and OHT, presenting with IOP levels exceeding 25 mmHg. Thai Clinical Trials Registry number was TCTR20180912007. Optical biometry, encompassing measurements such as corneal thickness (CCT), keratometry, anterior chamber depth (ACD), and axial length, was conducted before and after IOP reduction. The IOL power was also determined using the SRK/T formula. The main outcomes measured were alterations in biometry and IOL power. Correlations between IOP, biometric parameters, and IOL power were analyzed. In total, 28 eyes were included in the study, with a mean patient age of 65.71±10.2 years. After IOP reduction, all biometric parameters, except CCT and ACD, exhibited a decrease without reaching statistical significance (all p>0.05). Meanwhile, IOL power showed a slight increase of 0.214±0.42 diopters (P = 0.035). The correlation between IOP and biometric parameters was found to be weak. However, there was a moderate correlation between IOP and IOL power (r2 = 0.267). Notably, IOL power tended to increase by more than 0.5 diopters when IOP decreased by more than 10 mmHg (p < 0.001). In conclusion, changes in IOP among patients with POAG and OHT do not significantly impact biometry and IOL power calculations. Nonetheless, it may be prudent to consider a slight adjustment in IOL power when IOP is lowered by more than 10 mmHg.

Agreement of IOL power and axial length obtained by IOLMaster 500 vs IOLMaster 500 with Sonolink connection.

BACKGROUND: The accurrate and expedient ocular biometry is essential for modern cataract surgery. IOLMaster 500, one of the most popular partial coherence interferometry (PCI) device, has been widely used. However, with the PCI device, it is difficult to obtain the axial length through densely opaque media. With the current version of IOLMaster 500, a unique feature is added to link with the Synergy immersion A-scan ultrasound (sonolink connection). In case of failure to measure axial length by IOLMaster 500, the axial length can be obtained by ultrasound, and then transferred to IOLMaster 500 for the IOL power calculation. This study aims to compare the results and evaluate the agreement between IOL power and axial length obtained by IOLMaster 500 and IOLMaster 500 with sonolink connection. METHODS: A prospective study of 60 eyes in 60 mild-to-moderate cataract patients was conducted under Institutional Ethics Committee approval. Keratometry (K) and axial length (AL) of all eyes were measured using IOLMaster 500 (Carl Zeiss, Germany), then IOL power was generated using Holladay 1 formula (group 1). After 5 min, the K measurements were repeated with IOLMaster 500 and the AL were measured again using the Synergy A-scan ultrasound (Accutome, USA). Then, the AL data were transferred to IOLMaster 500 via the sonolink connection to generate the IOL power using the same setting (group 2). The IOL power and AL were compared between the two groups, and the agreement was evaluated using intraclass correlation coefficient (ICC) and the Bland-Altman method. RESULTS: The mean IOL power in group 1 was 21.04 + 2.36 D and group 2 was 21.03 + 2.36 D. The mean AL in group 1 was 23.35 + 0.86 mm and in group 2 was 23.36 + 0.86 mm. There was no statistically significant difference in IOL power and AL between the two groups. The agreements in IOL power and AL between both groups were high (ICCs = 0.997 for IOL power and 0.993 for AL) CONCLUSIONS: The IOL power and AL derived from both groups were similar. The agreements between them were high.

Accuracy of Holladay 2 formula using IOLMaster parameters in the absence of lens thickness value.

BACKGROUND: The accuracy of the Holladay 2 (H2) formula is well-documented. This formula requires seven variables to estimate effective lens position (ELP) for the IOL power calculation. The lens thickness (LT) value is one of the required variables. Interestingly, the IOLMaster, which is one of the most commonly used optical biometers, can provide all the required ocular variables except LT value. It has become a pertinent issue to evaluate the accuracy of theH2 formula when it is used without the LT value. The purpose of this study was to evaluate the results when using the H2 formula, without the LT value, and compare such results to those obtained using the Haigis formula and the Hoffer Q formula. METHODS: The Institutional review board (IRB) gave their approval for the conduct of this prospective comparative study. One hundred and sixty-three eyes of 143 cataract patients from the Ophthalmology Department, Siriraj Hospital, Thailand were recruited. All eyes were measured using the IOLMaster (Carl Zeiss Meditec, Jena, Germany) for keratometry (K), axial length (AL), anterior chamber depth (ACD), and horizontal white-to-white (WTW) corneal diameter. Then, the LT measurement was obtained by A-scan ultrasonography (Quantel Axis-II, Quantel Medical, USA). Every patient underwent uncomplicated phacoemulsification by a single surgeon (NC) with a single technique using a single IOL model. Post-operative refraction was obtained at 3 months. The mean absolute errors (MAEs), median absolute errors (MedAEs) and percentage of the eyes within ±0.25, ±0.50, and ±1.00 D of predicted refraction was calculated for H2 formula both with and without LT input, Haigis, and Hoffer Q formula. The results were also classified into a group of short AL (<22.0 mm), average AL (22.0 to 24.5 mm) and long AL (>24.5 mm). RESULTS: There was no statistically significant difference in either MAEs or MedAEs of all formulas in all AL groups including the H2 with and without LT. There was a trend toward lower MAEs and MedAEs for H2 in the long AL group. Percentage of the eyes within ±0.25, ±0.50, and ±1.00 D of predicted refraction were similar in all AL groups. CONCLUSION: The preliminary results of this study showed that the H2 formula performed well even without the LT value. It was comparable to the Haigis and Hoffer Q formulas.

Genetic analysis of allogenic donor cells after successful allo-limbal epithelial transplantation in simple and cultivated limbal epithelial transplantation procedures.

This non-comparative cohort study investigated long-term donor cell survival after allogenic simple/cultivated limbal epithelial transplantations (allo-SLET/allo-CLET, respectively) by genetic analysis. Transplanted corneal epithelial cells, which underwent impression cytology and/or corneal-button biopsy, were examined for personal identities of autosomal short-tandem repeats; the percentages of donor cells were calculated based on matching recipient or donor buccal-DNA references. Twelve patients were included; 4 underwent allo-CLET, 8 underwent allo-SLET. Eight patients (67%) had total limbal stem cell deficiency (LSCD). Genetic analysis was performed postoperatively (mean, 55.3 months). Donor cells were detected in 4 of 12 patients (25%), all of whom underwent allo-SLET; 1 patient had a donor genotype and 3 patients had a mixed donor/recipient genotype. The longest time of donor cell detection was 30 months. Seven patients (58%) used systemic immunosuppressives at the time of genetic analysis (mean use, 22.5 months). Allogenic donor cells survived in both procedures for the long term postoperatively, which encourages the long-term use of systemic immunosuppressives. Donor cells may not be the only factor in graft survival, in that most successful cases had a recipient profile. Their presence for a specific time may promote niches for the patients' own cells to repopulate, especially for partial LSCD.

Corneal nerve regeneration is affected by scar location in herpes simplex keratitis: A longitudinal in vivo confocal microscopy study.

PURPOSE: To assess the effect of corneal scar location on corneal nerve regeneration in patients with herpes simplex virus (HSV) keratitis in their affected and contralateral eyes over a 1-year period by in vivo confocal microscopy (IVCM), and to correlate these findings to corneal sensation measured by Cochet-Bonnet Esthesiometer. METHODS: Prospective, longitudinal, case-control study. Bilateral corneal nerve density and corneal sensation were analyzed centrally and peripherally in 24 healthy controls and 23 patients with unilateral HSV-related corneal scars using IVCM. RESULTS: In the central scar (CS) group, total nerve density in the central cornea remained significantly lower compared to controls at follow-up (11.05 ± 1.97mm/mm2, p < 0.001), and no significant nerve regeneration was observed (p = 0.090). At follow-up, total nerve density was not significantly different from controls in the central and peripheral cornea of the peripheral scar (PS) group (all p > 0.05), but significant nerve regeneration was observed in central corneas (16.39 ± 2.39mm/mm2, p = 0.007) compared to baseline. In contralateral eyes, no significant corneal nerve regeneration was observed in central or peripheral corneas of patients with central scars or peripheral scars at 1-year follow-up, compared to baseline (p > 0.05). There was a positive correlation between corneal nerve density and sensation in both central (R = 0.53, p < 0.0001) and peripheral corneas (R = 0.27, p = 0.0004). In the CS group, the corneal sensitivity was <4 cm in 4 (30.8%) and 7 (53.8%) patients in the central and peripheral corneas at baseline, and in 5 (38.5%) and 2 subjects (15.4%) at follow-up, whereas in the PS group only 1 patient (10%) showed a corneal sensation < 4 cm in the central cornea at baseline, and only 1 (10.0%), 3 (30.0%) and 1 (10.0%) patients at follow-up in the central, affected and opposite area of the cornea, respectively. CONCLUSION: The location of HSV scarring in the cornea affects the level of corneal nerve regeneration. Eyes with central corneal scar have a diminished capacity to regenerate nerves in central cornea, show a more severe reduction in corneal sensation in the central and peripheral corneas that persist at follow-up, and have a reduced capability to restore the corneal sensitivity above the cut-off of 4 cm. Thus, clinicians should be aware that CS patients would benefit from closer monitoring for potential complications associated with neurotrophic keratopathy, as they have a lower likelihood for nerve regeneration.

Precision analysis of posterior corneal topography measured by Visante Omni: repeatability, reproducibility, and agreement with Orbscan II.

PURPOSE: To evaluate the repeatability and reproducibility of posterior corneal curvature and posterior corneal elevation best-fit sphere (BFS) obtained with the Visante Omni (Carl Zeiss Meditec) and to compare the results with the Orbscan II (Bausch & Lomb). METHODS: Thirty eyes from 30 healthy volunteers were included in this study. All patients were examined 5 times with the Visante Omni and Orbscan II by 2 independent operators. The posterior corneal curvature (3- and 6-mm zone) and posterior corneal elevation BFS (5- and 8-mm zone) were generated for each system. Intraoperator repeatability and interoperator reproducibility and agreement between the systems were evaluated using the intraclass correlation coefficient (ICC) and the Bland-Altman method. RESULTS: The repeatability of posterior corneal curvature and posterior corneal elevation BFS measured by the Visante Omni was high for all analysis zones (ICC, 0.99 to 1.00). The reproducibility also showed similar results (ICC, 0.99 to 1.00). Agreement between the Visante Omni and Orbscan II was high for posterior corneal curvature (ICC, 0.94 to 0.97) and posterior corneal elevation BFS (ICC, 0.96 to 0.98) with 95% limits of agreement at -0.26 to 0.22 diopters for posterior corneal curvature and 0.11 to 0.69 mm for posterior corneal elevation BFS. CONCLUSIONS: The Visante Omni provides good repeatability and reproducibility of posterior corneal topography. Overall agreement with the Orbscan II system was high.

Effect of herpes simplex keratitis scar location on bilateral corneal nerve alterations: an in vivo confocal microscopy study.

AIMS: To evaluate the impact of herpes simplex virus (HSV)-induced scar location on bilateral corneal nerve alterations using laser in vivo confocal microscopy (IVCM). METHODS: Central and peripheral corneal subbasal nerve density (CSND) were assessed bilaterally in 39 patients with unilateral HSV-induced corneal scars (21 central scars (CS), 18 peripheral scars (PS)) using IVCM. Results were compared between patients and 24 age-matched controls. CSND was correlated to corneal sensation for all locations. RESULTS: Overall patients revealed significant decrease of CSND in the central and peripheral cornea (9.13±0.98 and 6.26±0.53 mm/mm2, p<0.001), compared with controls (22.60±0.77 and 9.88±0.49 mm/mm2). CS group showed a decrease in central (8.09±1.30 mm/mm2) and total peripheral nerves (5.15±0.62 mm/mm2) of the affected eyes, whereas PS group demonstrated a decrease in central (10.34±1.48 mm/mm2) and localised peripheral nerves only in the scar area (4.22±0.77 mm/mm2) (all p<0.001). In contralateral eyes, CSND decreased in the central cornea of the CS group (16.88±1.27, p=0.004), and in the peripheral area, mirroring the scar area in the affected eyes of the PS group (7.20±0.87, p=0.032). Corneal sensation significantly decreased in the whole cornea of the affected, but not in contralateral eyes (p<0.001). A positive correlation between CSND and corneal sensation was found in all locations (p<0.001). CONCLUSIONS: Patients with HSV scar demonstrate bilateral CSND decrease as shown by IVCM. CSND and corneal sensation decrease in both central and peripheral cornea in affected eyes, although only in the scar area in PS group. Interestingly, diminishment of CSND was found locally in the contralateral eyes, corresponding and mirroring the scar location in the affected eyes.

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.

Provocation of dry eye disease symptoms during COVID-19 lockdown.

To assess the impact of COVID-19 lockdown measures on dry-eye symptoms in a community-based population, a cross-sectional study was conducted during the first wave of the COVID-19 outbreak in Thailand. An online survey was distributed via social media between June and July 2020. The questionnaire elicited information on demographics, dry-eye symptoms, use of visual display terminals, and mental health status. There were 535 respondents. Thirty-seven percent reported having been diagnosed with dry-eye disease (DED). During the lockdown, the mean dry-eye symptom score (DESS) of overall participants dropped significantly from 81.6 ± 15.9 to 79.8 ± 17.4 (P < 0.001). The mean, daily, visual display terminal (VDT) usage increased from 10.55 ± 5.16 to 13.08 ± 5.65 h (P < 0.001). A negative correlation between age and VDT usage was observed in both the normal and lockdown situations. One-quarter of all participants had an abnormal mental health status. The female gender (OR 1.86; 95% CI 1.14-3.04) and increased VDT usage during the lockdown (OR 5.68; 95% CI 3.49-9.23) were independently associated with worsening dry-eye symptoms. The lockdown measures abruptly altered the behaviors and lifestyles of the overall population. Excessive exposure to VDTs were associated with deteriorated dry-eye symptoms, and it possibly contributed to the increased DED incidence in the surveyed population.

Characteristics of Corneal Subbasal Nerves in Different Age Groups: An in vivo Confocal Microscopic Analysis.

PURPOSE: To determine the normative characteristics of corneal subbasal nerves in different age groups using laser scanning in vivo confocal microscopy (IVCM). PATIENTS AND METHODS: This descriptive observational study recruited healthy subjects (aged 20-60 years) from Siriraj Health-Screening Center. Excluded were individuals who had abnormal ocular symptoms, previous ocular surgery, a history of any diseases related to systemic and/or corneal neuropathy, or abnormal corneal sensitivity. Corneal IVCM (HRT3/Rostock Corneal Module) was performed at the central cornea to analyze the subbasal nerve plexus. The corneal nerve characteristics, comprising the number and density of nerves (main nerve trunks, branches, and total nerves) were analyzed using the NeuronJ program, and the corneal nerve tortuosity was graded. The correlations between the subbasal nerve density, tortuosity and age were then analyzed. RESULTS: Eighty subjects were enrolled, with twenty in each of four age groups (20-30, >30-40, >40-50, and >50-60 years). Overall, the mean number and density of main nerve trunks were 27.93±0.81/mm2 and 11.22±0.30 mm/mm2, respectively. As of the nerve branches, the average number and density were 103.56±2.37/mm2 and 9.15±0.30 mm/mm2, respectively. The total nerve density was 20.37±0.39 mm/mm2. There were no significant differences between subbasal nerve parameters of the four age groups. It is noteworthy that 65% of the subjects aged over 40 years revealed high-grade nerve tortuosity. CONCLUSION: The corneal subbasal nerve numbers and densities were not significantly different among a healthy population aged 20-60 years. However, there was a trend towards high tortuosity of the corneal nerve in people aged over 40 years.

Successful Ocular Surface Reconstruction in Complete Ankyloblepharon With the Simple Oral Mucosal Epithelial Transplantation Technique: A Case Report.

PURPOSE: To report an outcome of a patient with complete ankyloblepharon successfully managed with simple oral mucosal epithelial transplantation (SOMET). METHODS: A 55-year-old woman presented with complete adhesion of both lids to the ocular surface as a complication from Stevens-Johnson syndrome. We performed 2-staged reconstructive surgeries: the first stage was to perform ankyloblepharon lysis and surface reconstruction with a mucosal graft on the palpebral area and an amniotic membrane on the bulbar area, and the second stage was to reconstruct the bulbar area with a transplantation of small pieces of oral mucosa (SOMET technique). Postoperatively, the patient was evaluated for ocular surface stability, recurrent symblepharon, in vivo confocal microscopy, and impression cytology with immunofluorescence staining. RESULTS: Complete epithelialization of cornea-like epithelium was observed within 6 weeks after SOMET was performed. The ocular surface was stable over 1 year. Both fornices remained deep. In vivo confocal microscopy showed cornea-like epithelium mixed with conjunctival epithelium, as confirmed with immunofluorescence staining, which revealed cytokeratin 3, cytokeratin 7, and cytokeratin 12 positivity. CONCLUSIONS: SOMET is a simple modified technique using minimal oral mucosal tissue to regenerate epithelialization for complicated ocular surface reconstruction such as a complete ankyloblepharon repair. Although there was evidence of conjunctival invasion, stable ocular surface and deep fornices can be achieved for further visual rehabilitative procedure.

Phenotypic Characterization of Corneal Epithelium in Long-Term Follow-Up of Patients Post-Autologous Cultivated Oral Mucosal Epithelial Transplantation.

PURPOSE: To analyze the phenotype of the corneal epithelium in patients with long-term follow-up who underwent autologous cultivated oral mucosal epithelial transplantation (COMET) using in vivo confocal microscopy (IVCM) and impression cytology with immunofluorescence staining (ICIF). METHODS: Thirteen eyes from patients with severe limbal stem cell deficiency, who underwent COMET at least 48 months before, were recruited in this noncomparative cohort study. After eye examination, IVCM and ICIF were performed. Clinical manifestations of the cornea were evaluated and compared with epithelial findings detected by IVCM and ICIF [cytokeratin (CK) 3, CK7, and CK12]. Two corneal buttons derived from patients receiving the corneal transplantation post-COMET were sent for immunohistochemistry (CK3, CK6, CK7, CK12, paired box gene 6, p63, zonula occludens-1, and integrin ß -1). RESULTS: The mean age of patients was 51.2 ± 20.6 years, and the mean follow-up time since COMET was 78.7 ± 16.3 months. Six of 13 eyes showed clinically successful COMET. In these eyes, IVCM demonstrated predominant cornea-like epithelium and ICIF reported positivity for CK3 and CK12, confirming the presence of oral mucosal and corneal epithelium. Meanwhile, 7 eyes showed total conjunctivalization, corresponding with substantial conjunctival epithelium detected by IVCM and positivity for conjunctival (CK7) and oral mucosal epithelial (CK3) markers detected by ICIF. The immunohistochemistry of corneal buttons stained positive for oral mucosal, corneal epithelial, and stem cell markers (CK3, CK12, and p63). CONCLUSIONS: In long-term follow-up of COMET, epithelium of successful patients demonstrated cornea-like phenotype, whereas failed cases revealed mainly conjunctival phenotype. However, there were evidences that oral mucosal epithelial cells remained across the cornea in both successful and failed COMET as detected by IVCM and ICIF.

Efficacy and outcome of simple limbal epithelial transplantation for limbal stem cell deficiency verified by epithelial phenotypes integrated with clinical evaluation.

PURPOSE: To evaluate the efficacy and outcome of simple limbal epithelial transplantation (SLET) for limbal stem cell deficiency (LSCD) using epithelial phenotype detection integrated with clinical manifestation. METHODS: This prospective multicenter study included patients with LSCD who underwent autologous SLET (autoSLET) and living-related allogenic SLET (Lr-alloSLET). All patients were assessed by slit-lamp biomicroscopy, in vivo confocal microscopy (IVCM), and impression cytology with immunofluorescence staining (ICIF) before and after surgery. The criteria for success were the presence of a clinically non-conjunctivalized cornea and corneal epithelium detected by IVCM or ICIF. Otherwise, the case would be considered a failure. Visual improvement and risk factors for SLET failure were analyzed. RESULTS: A total of 28 eyes of 26 patients (11 autoSLET and 17 Lr-alloSLET) were included. The median age was 53 years (range, 35-63), and the follow-up time was 29.5 months (range, 17.5-39.8). The overall survival rate was 89.3% at 2 years and 75.6% at 3 years with no difference between autoSLET and Lr-alloSLET (p = 0.24). Seven eyes subsequently underwent penetrating keratoplasty. Immunohistochemistry analysis showed that all corneal buttons had corneal epithelium and limbal stem cell markers. Visual improvement was achieved in both SLET groups (p < 0.001). Failed SLET developed between 5 and 32 months postoperatively. However, absolute risk factors for SLET failure were unidentified. CONCLUSION: The efficacy of autoSLET and Lr-alloSLET for LSCD was excellent. Limbal explants can regenerate and restore the corneal surface while maintaining the characteristics of limbal stem cells as shown by epithelial phenotype detection and immunohistochemistry integrated with clinical evaluation.

Eyeliner Induces Tear Film Instability and Meibomian Gland Dysfunction.

PURPOSE: To compare the degree of tear film instability and severity of meibomian gland dysfunction between subjects who use eyeliner and those who do not use eyeliner. METHODS: This cross-sectional study included 42 healthy volunteer women who had no dry eye symptoms (Ocular Surface Disease Index score < 13) and aged between 18 and 40 years. The subjects were classified into 2 groups: an eyeliner-use group (EL: regularly used eyeliner ≥3 d/wk and continuously used ≥6 mo) and a noneyeliner-use group as controls. A questionnaire for ocular surface symptoms using a visual analog scale was administered. Then, a number of eye tests were performed [grading of conjunctival inflammation, fluorescein tear breakup time, ocular surface fluorescein staining, Schirmer I, evaluation of meibomian gland (MG) function, detection of eyelid margin abnormalities, and Demodex detection]. RESULTS: Tear breakup time was significantly lower in the EL group compared with controls (3.0 ± 1.9 vs. 5.8 ± 2.1 s, P < 0.001). MG grading was significantly higher in the EL group than in controls (P = 0.004); higher grade (grades 2-3) was found in 85.7% of EL and 47.6% of controls. Meiboscore was also higher in EL than in controls (P = 0.001). Regarding the morphological changes in lid margin, only telangiectasia was detected significantly more in EL (28.6%) compared with controls (4.8%) (P = 0.041). Conjunctival inflammation was observed 4 times more in EL (66.7%) than in controls (14.3%), P = 0.001. Other outcomes included ocular surface symptoms and fluorescein staining scores, and Schirmer I and Demodex detection were not significantly different between both groups. CONCLUSIONS: The regular use of eyeliner induces tear film instability and MG dysfunction.

Characterization of limbal explant sites: Optimization of stem cell outgrowth in in vitro culture.

Simple limbal epithelial transplantation (SLET) and cultivated limbal epithelial transplantation (CLET) are proven techniques for treating limbal stem cell deficiency (LSCD). However, the precise regions that are most suitable for preparing explants for transplantation have not been identified conclusively. Accordingly, this in vitro study aimed at determining ideal sites to be selected for tissue harvest for limbal stem cell culture and transplantation. We evaluated cell outgrowth potential and the expression of stem cell markers in cultures from 48 limbal explants from five cadaveric donors. The limbal explants were generated from the three specific sites: Lcor (located innermost and adjacent to the cornea), Lm (middle limbus), and Lconj (located outermost adjacent to the conjunctiva). We found that explants from the Lconj and Lm sites exhibited higher growth potential than those from the Lcor site. Transcript encoding the stem cell marker and p63 isoform, ΔNp63, was detected in cells from Lm and Lconj explants; expression levels were slightly, though significantly (p-value < 0.05), higher in Lm than in Lconj, although expression of ΔNp63α protein was similar in cells from all explants. Differential expression of ATP-Binding Cassette Subfamily G Member 2 (ABCG2) did not reach statistical significance. Immunohistochemistry by indirect immunofluorescence analysis of limbus tissue revealed that the basal layer in explant tissue from Lconj and Lm contained markedly more stem cells than found in Lcor explant tissue; these findings correlate with a higher capacity for growth. Collectively, our findings suggest that explants from the Lconj and Lm sites should be selected for limbal cell expansion for both CLET and SLET procedures. These new insights may guide surgeons toward specific limbal sites that are most suitable for stem cell culture and transplantation and may ultimately improve treatment outcomes in the patients with LSCD.