Topical insulin for refractory persistent corneal epithelial defects.

The aim was clinical evaluation of the efficacy of topical insulin eye drops in patients with refractory persistent epithelial defects (PEDs). This prospective non-randomized investigation was conducted to examine the efficacy of insulin eye drops in treating patients with PEDs that did not respond to conventional therapy. A total of twenty-three patients were included in the study, and they were administered insulin eye drops formulated as 1 U/mL, four times a day. The rate of epithelial defect resolution and time to complete corneal re-epithelialization were considered primary outcome measures. The relative prognostic impact of initial wound size and other parameters, including age, sex, smoking, diabetes, and hypertension were also analyzed. The results showed that during follow-up (maximum 50 days), a total of 16 patients (69.6%) achieved improvement. Insulin eye drops significantly reduced the corneal wounding area in 75% of patients with small epithelial defects (5.5 mm2 or less) during 20 days. Only 61% of patients with moderate epithelial defects (5.51-16 mm2) showed a significant recovery in 20-30 days. Also, 71% of patients with a defect size greater than 16 mm2, demonstrated a significant improvement in the rate of corneal epithelial wound healing in about 50 days. In conclusion topical insulin reduces the PED area and accelerates the ocular surface epithelium wound healing.

Corneal Epithelial Thickness Mapping: A Major Review.

The corneal epithelium (CE) is the outermost layer of the cornea with constant turnover, relative stability, remarkable plasticity, and compensatory properties to mask alterations in the underlying stroma. The advent of quantitative imaging modalities capable of producing epithelial thickness mapping (ETM) has made it possible to characterize better the different patterns of epithelial remodeling. In this comprehensive synthesis, we reviewed all available data on ETM with different methods, including very high-frequency ultrasound (VHF-US) and spectral-domain optical coherence tomography (SD-OCT) in normal individuals, corneal or systemic diseases, and corneal surgical scenarios. We excluded OCT studies that manually measured the corneal epithelial thickness (CET) (e.g., by digital calipers) or the CE (e.g., by confocal scanning or handheld pachymeters). A comparison of different CET measuring technologies and devices capable of producing thickness maps is provided. Normative data on CET and the possible effects of gender, aging, diurnal changes, refraction, and intraocular pressure are discussed. We also reviewed ETM data in several corneal disorders, including keratoconus, corneal dystrophies, recurrent epithelial erosion, herpes keratitis, keratoplasty, bullous keratopathy, carcinoma in situ, pterygium, and limbal stem cell deficiency. The available data on the potential role of ETM in indicating refractive surgeries, planning the procedure, and assessing postoperative changes are reviewed. Alterations in ETM in systemic and ocular conditions such as eyelid abnormalities and dry eye disease and the effects of contact lenses, topical medications, and cataract surgery on the ETM profile are discussed.

Effect of ocular biometric factors on corneal biomechanical properties.

PURPOSE: To evaluate the effects of ocular biometric variables on corneal biomechanical properties. METHODS: A total of 102 eyes of 102 participants were enrolled in this cross-sectional study. The axial length (AL) was determined by an IOL master 500 and measurements of corneal biomechanical properties were performed using Corvis ST, integrated with pentacam results. RESULTS: Aging and corneal steepening were associated with less corneal deformability and higher movement of the entire eye. Longer AL corresponded with greater deformability and lower corneal viscous damping properties and less whole eye movement (all P-values < 0.05). In contrast to mean keratometry (Mean K) and corneal diameter, anterior chamber depth (ACD) and AL have a significant effect on corneal biomechanical parameters. Corneal biomechanical index (CBI) was not significantly correlated with any of biometric parameters. Stress-strain index (SSI) was significantly correlated with age (r = 0.470), spherical equivalent (SE) (r = 0.537), AL (r = -0.534) and ACD (r = -0.316) (all P-values < 0.001). CONCLUSIONS: In normal individuals, several parameters such as age, ACD, AL and Mean K have a great impact on corneal biomechanical properties; thereby, these effects should be taken into account prior to interpretation of corneal biomechanics, particularly in older ages and eyes with longer AL and steeper cornea.

Agreement Between Swept-source Optical Coherence Tomography and Rotating Scheimpflug Camera in Measurement of Corneal Parameters in Normal and Keratoconic Eyes.

Purpose: This study aimed to assess the agreement between topographic indices of healthy subjects and keratoconus (KCN) patients using a swept-source optical coherence tomography (SS-OCT CASIA2) versus a Scheimpflug camera (Pentacam). Methods: 40 eyes of 23 patients with KCN and 40 eyes of 20 healthy subjects were included and evaluated with the CASIA2, followed by the Pentacam. Two consecutive modalities were obtained for one eye of each patient. Corneal parameters, including anterior keratometry at steep (Ks) and flat meridians (Kf), anterior astigmatism, anterior and posterior corneal elevation values, thinnest corneal thickness, and apex corneal thickness, were evaluated. Results: CASIA2 and Pentacam showed perfect agreement (95% limits of agreement (LoA): -0.22 to 0.68, 95% LoA: -1.5 to 1.44 D) and good correlation (Intraclass correlation (ICC):0.986, ICC:0.987; P<0.01) for anterior (Ks) in normal and ectatic corneas, respectively. The cylinder amount had moderate agreement and correlation (95% LoA: -0.55 to 0.47D, ICC: 0.797, P<0.01) in normal, and moderate to strong agreement and correlation (95% LoA: -1.57 to 0.87D, ICC=0.911, P<0.01) in Keratoconic eyes. There was a fair agreement for anterior and posterior corneal elevation values in normal subjects (95% LoA: -3.09 to 4.59, 95% LoA: -6.91 to 7.31D). The thinnest corneal thickness amount had an excellent agreement in normal and KCN patients (ICC: 0.983, 0.953; respectively). Conclusion: Although the devices had different mean indices values, they had a good agreement based on the Bland-Altman plots. Since Pentacam is accepted as the standard tool for diagnosing ectatic cornea, pentacam CASIA2 is also helpful for early diagnosis of KCN.

Effects of Descemet Stripping Automated Endothelial Keratoplasty on Corneal Densitometry of Cases with Long-Standing Pseudophakic Bullous Keratopathy.

Purpose: To quantify the effects of Descemet stripping automated endothelial keratoplasty (DSAEK) on corneal clarity and densitometry of patients with long-standing pseudophakic bullous keratopathy (PBK) complicated with subepithelial fibrosis. Methods: Thirty-four eyes with PBK complicated with corneal edema for more than 6 months and subepithelial fibrosis were enrolled. All subjects underwent complete ophthalmic examination and corneal densitometry module of Pentacam HR, before and 1, 3, and 6 months after DSAEK. Results: Thirteen patients were excluded due to postoperative complications or missed to follow-up visits. Finally, twenty-one patients' data were analyzed. Corneal densitometry measures significantly decreased in all three layers (anterior, central, and posterior) 3 and 6 months after surgery compared to preoperative values; however, the differences did not reach statistical significance in the 1st month. Moreover, densitometry measurements were significantly lower at month 6 compared to month 1, but not at month 3 compared to month 1. Corneal densitometry of the anterior layer was significantly higher than central and posterior layers in 2 mm and 6 mm zones preoperatively and at all postoperative visits. Corneal light backscatter of each three layers was not statistically different between 0-2 mm and 2-6 mm in all pre- and postoperative visits. Conclusions: Corneal densitometry in cases of PBK begins to improve after DSAEK in different layers in a slow and continued trend which takes up to 6 months for an effect to be seen. Interestingly, this improvement is possible even in complicated corneas with long-standing edema. Hence, corneal densitometry can be used as an objective method for quantification of the outcome of DSAEK in complicated cases of PBK.

Role of Different Types of Contact Lenses in Epithelial Thickness.

OBJECTIVE: To evaluate the potential role of different types of contact lenses, such as soft (SCL), hard (HCL), and mini scleral (SCCL), in corneal epithelial thickness with anterior segment optical coherence tomography (AS-OCT). METHODS: In this cross-sectional study, patients who used contact lens at recent 6 months were recruited consecutively from September 2019 to October 2019, and the epithelial thicknesses of the cornea were obtained by AS-OCT and compared with control subjects who did not use contact lens. RESULTS: In total, 184 eyes (115 subjects) were included; of them, 75 eyes were keratoconic (KCN) and 109 eyes were nonkeratoconic (non-KCN). Twenty eyes in KCN and 79 eyes of non-KCN group had no history of contact lens use and were included for comparison with KCN and non-KCN contact lens users, respectively. Mean duration of contact lens wearing was 75.63±50.42 months. The epithelial thickness of non-KCN SCL group was thinner than that of non-KCN control subjects all over the cornea, whereas the epithelium of non-KCN HCL was thinner at central site as well as nasal and temporal paracentral and midperipheral areas. Epithelial thickness of the KCN HCL group was not different from the KCN control subjects in all sectors. The KCN SCCL group had thinner epithelium at nearly all peripheral sectors as well as inferior, inferotemporal, inferonasal, and nasal midperipheral sectors compared with KCN control subjects. CONCLUSION: The corneal epithelium was thinner at the peripheral zones in KCN SCCL users; at both peripheral and central zones in non-KCN SCL users and in central zones in non-KCN HCL users.

Clinical outcomes of transepithelial photorefractive keratectomy with epithelial ablation targeting actual epithelial thickness vs default laser platform values.

PURPOSE: To investigate the clinical outcomes of transepithelial photorefractive keratectomy (tPRK) with actual epithelial thickness vs default software values. SETTING: Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. DESIGN: Prospective controlled study. METHODS: Patients with refractive spherical error of -1.50 to -7.00 diopters (D) and refractive astigmatism up to 4.00 D were consecutively enrolled and divided into 2 groups: group 1 undergone tPRK with actual central and peripheral epithelial thickness input in right eyes, group 2 undergone tPRK with actual central and 10 mm higher peripheral epithelial thickness in right eyes. Left eyes in both groups underwent tPRK with default protocol. Outcome measures were induced refractive error, achieved optical zone (OZ), and wasted stromal tissue. RESULTS: 83 patients were included in this study. Mean ± SD of induced spherical equivalent was +0.15 ± 0.39 D and +0.01 ± 0.35 D in right and left eyes of group 1 (P = .01) and +0.04 ± 0.22 D and +0.03 ± 0.23 D in right and left eyes of group 2 (P = .75), respectively. There was no statistically significant difference between wasted tissue between right and left eyes in group 1 and group 2 (P = .77 and P = .49, respectively). OZ contraction was significantly higher in right compared with left eyes in group 1 (P = .05), but not in group 2 (P = .95). CONCLUSIONS: In tPRK, refractive outcomes, wasted tissue, and OZ contraction depend little on preexisting corneal epithelial thickness in corneas with normal range epithelial thickness. However, OZ contraction may be a concern in lower amount of ablations.

Recombinant Interferon Alpha-2b as Primary Treatment for Ocular Surface Squamous Neoplasia.

PURPOSE: To investigate the effects of topical and perilesional interferon alpha-2b as primary treatment for ocular surface squamous neoplasia (OSSN). METHODS: In this prospective interventional case series, topical interferon alpha-2b (3 MIU/mL) was used as the initial treatment of OSSN, with perilesional interferon alpha-2b (3 MIU/mL) added based on clinical response. The primary outcome was complete tumor resolution. Spearman's rank correlation test was used to investigate the association of complete tumor resolution and time to resolution with baseline tumor characteristics and the American Joint Committee on Cancer (AJCC) classification for OSSN. RESULTS: Ninety-two patients (92 OSSN tumors) were included in the study. The total follow-up duration was 13.57 ± 2.14 months (median: 12, range: 3-23). The median basal tumor diameter was 4 mm (mean: 4.13 ± 1.37). Complete tumor resolution was achieved in 89 cases (96.73%), with a median time to complete tumor resolution of 5 months (mean: 4.64 ± 1.92). Complete tumor resolution was 57 of 57 in T1 (100%), 8 of 9 in T2 (88.88%), and 21 of 23 in T3 (91.30%). There were statistically significant correlations between AJCC classification and complete tumor resolution (Spearman's r = -0.22, P = 0.03) and maximal basal tumor diameter and the time to complete resolution (Spearman's r = 0.35, P = 0.001). There were no recurrences during the study follow-up period. CONCLUSION: Topical interferon alpha-2b is effective and well tolerated as a primary treatment for OSSN, with a high rate of tumors responding completely to therapy.

In vivo Confocal Microscopic Evaluation of Corneal Changes in Acute Endothelial Rejection.

PURPOSE: To evaluate the microstructural corneal changes during acute endothelial graft rejection and following treatment using in vivo confocal microscopy (IVCM). METHODS: Patients with a clinical diagnosis of severe acute endothelial graft rejection following penetrating keratoplasty were included in this study. IVCM was performed on the 1st day the patient presented with rejection signs and at the time of clinical resolution. RESULTS: Twenty-three patients were included in this study. Inflammatory cells appeared as dendritic cells (DCs) and less frequently, as non-DCs in basal epithelial and subbasal areas. Activated keratocytes (AKs) (type 1: large cells with visible cytoplasmic processes; type 2: elongated and spindle-shaped keratocytes) were visible in acute phase. Following resolution, type 1 AKs considerably reduced, but type 2 cells were more often persisted. Multiple types of keratic precipitates (KPs) were also visible in acute phase which resolved following resolution of rejection. CONCLUSIONS: Acute graft rejection was associated with an increase in the number of DCs, activation of keratocytes, and aggregation of various types of KPs. Inflammatory process subsided in almost all cases, but the IVCM changes did not return to normal early after clinical resolution of rejection.

Efficacy of probing adjunctive with low-dose mitomycin-C irrigation for the treatment of epiphora in adults with nasolacrimal duct stenosis.

PURPOSE: The purpose of the study was to investigate the efficacy of adjunctive low-dose mitomycin-C (MMC) during successful lacrimal duct probing in adults with nasolacrimal ducts (NLDs) stenosis. MATERIALS AND METHODS: This is a prospective case-control study on patients with NLD stenosis who were randomized into two groups. All patients underwent probing without or with an application of MMC. Former group received 0.2 mg/ml MMC irrigation for 5 min. The main outcome measures were objective evaluation of patency with irrigation, as well as patients' subjective assessment of improvement. RESULTS: There were 73 eyes in 58 consecutive patients; patient mean age ranged from 19 to 78 years (mean 44 years). Female included larger group of patients (63%) and mean duration of the symptoms was 26.1 months (range, 2-120 months). After mean follow-up of 11 months (range, 9-14 months), 23 (60%) of the 38 eyes in the MMC groups and 8 (22%) of the 35 eyes in control group had complete response and remained symptom free. This difference was statistically significant (P = 0.005). According to the patient's satisfaction, epiphora was partially improved in 6 (17%) eyes of control group and 4 (10%) eyes in MMC group. Application of MMC has a better outcome in patients with severe stenosis (P = 0.007); patients who had symptoms more than 12 months (P = 0.02) and patients with constant epiphora were compared with intermittent symptoms (P = 0.001). No complications were detected during patients follow-up. CONCLUSION: This study suggests acceptable long-term results for probing adjunctive with MMC irrigation for adults with NLD stenosis that can be recommended as a simple and effective procedure for these patients.

Longitudinal Epithelial Thickness Profile Changes 18 Months After Photorefractive Keratectomy.

PURPOSE: Long-term evaluation of corneal epithelial thickness (ET) profile changes after photorefractive keratectomy (PRK) using Fourier-domain anterior segment optical coherence tomography. METHODS: Three hundred twenty-six eyes of 163 patients were included in this prospective observational study. The corneal epithelial map was obtained across a 9-mm diameter area of the cornea before and up to 27 months after surgery. ET was assessed in 25 sectors and 4 annular zones (central 2 mm, paracentral 2-5 mm, midperipheral 5-7 mm, and peripheral 7-9 mm). RESULTS: There was a significant reduction in mean ET in all zones 1 month after PRK. Subsequently, ET increased in all annular zones. The change in mean ET became stable in the midperipheral and peripheral zones at 3 to 6 months and in the central zone at 12 months, and it continued to increase in the paracentral zone even after 18 months after surgery. The ET was 3.40 µm and 4.05 µm in the central and paracentral zones at 6 months, respectively. Postoperative spherical equivalent changed significantly only from 1 to 3 months (P < 0.04). There was a significant correlation between postoperative spherical equivalent at month 1 and ET change in the paracentral and midperipheral zones (P < 0.027). CONCLUSIONS: There is a significant reduction in ET 1 month after myopic PRK with a gradual thickening thereafter until it reaches stability at 12 months in the central zone. However, it continues to change even after 18 months in the paracentral zone. The greatest thickening is in the paracentral zone, followed by the central zone.

Changes in Corneal Subbasal Nerves after Punctal Occlusion in Dry Eye Disease.

PURPOSE: To evaluate corneal subbasal nerve plexus by in vivo confocal microscopy (IVCM) following punctal occlusion in patients with moderate to severe dry eye disease (DED). MATERIALS AND METHODS: Patients with grade 3 or 4 severity of DED based on Delphi Panel dry eye severity grading scheme were enrolled in the study. Permanent inferior punctal occlusion was performed. A comprehensive ophthalmic evaluation, including Ocular Surface Disease Index (OSDI) questionnaire, tear break-up time (TBUT), corneal fluorescein staining, conjunctival Rose bengal staining, Schirmer's test, and corneal sensation by Cochet-Bonnet esthesiometry, were performed at baseline, and 1 and 3 months after punctal occlusion. Furthermore, density and number of corneal subbasal nerves were evaluated by IVCM. RESULTS: Forty-one eyes of 23 patients with a mean age of 46.3 ± 9.0 years were enrolled. Corneal fluorescein staining, Rose bengal staining, and TBUT significantly improved at 3 months following punctal occlusion (p < .015). Corneal esthesiometry significantly increased at both postoperative visits (p < .03), and OSDI scores improved only at 3-month follow-up (p < .005). Nerve density and total number significantly increased 3 months after punctal occlusion (p < .045). Baseline nerve density had significant correlations with TBUT, fluorescein staining, Rose bengal staining (p < .012), but not with esthesiometry, Schirmer scores, or OSDI scores (p > .329). CONCLUSIONS: Corneal subbasal nerve density and total number increased following punctal occlusion in patients with moderate to severe DED. These findings were associated with improvements in corneal sensation, and signs and symptoms of DED. This emphasizes the effect of punctal occlusion in regeneration of corneal subbasal nerve plexus.

Repeatability and agreement of total corneal and sublayer pachymetry with 2 different algorithms of Fourier-domain optical coherence tomography in myopic and postphotorefractive keratectomy eyes.

PURPOSE: To investigate repeatability and agreement of total corneal and sublayer pachymetry with 2 different algorithms of Fourier-domain optical coherence tomography (OCT) in myopic and postphotorefractive keratectomy (PRK) eyes. SETTING: Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. DESIGN: Prospective observational study. METHODS: Total corneal, epithelial, and stromal thicknesses were measured using RTVue-XR OCT with Pachymetry + Cpwr (6.0 mm algorithm) and PachymetryWide (9.0 mm algorithm) scan patterns. The repeatability of 25 zones of 9.0 mm map and 17 zones of 6.0 mm map and the agreement between measurements of these 2 algorithms were calculated. RESULTS: Ninety-five myopic and 117 post-PRK patients were evaluated. By the 9.0 mm algorithm, coefficient of variation (CoV) for total cornea was 2.33% or lesser and 2.49% or lesser and for epithelium was 5.14% or lesser and 5.18% or lesser; and by the 6.0 mm algorithm, CoV for total cornea was 1.80% or lesser and 2.59% or lesser and for epithelial thickness was 3.08% or lesser and 4.80% or lesser in myopic and post-PRK eyes, respectively. Bland-Altman mean difference for epithelial thickness was 0.69 or lesser and 1.16 or lesser and 95% limits of agreement for epithelial thickness was 6.81 or lesser and 8.56 or lesser in myopic and post-PRK eyes, respectively. CONCLUSIONS: Good repeatability was seen in measurements of total corneal, stromal, and epithelial thicknesses by both algorithms. Agreement of the 2 algorithms in central zone was also good. However, large range of variation in paracentral thickness measurements did not allow us to consider these algorithms as interchangeable.

Herpes Zoster Ophthalmicus and Limbal Ischemia in A Patient with History of Ocular Graft-Versus-Host Disease.

PURPOSE: To report a rare complication of herpes zoster ophthalmicus (HZO). METHODS: A 27-year-old man with a history of graft-versus-host disease (GVHD) presented with pain and redness in his left eye along with vesicular eruptions on the same side of the forehead from 40 days earlier. RESULTS: In this case report, we present a case of HZO with severe limbal ischemia in a patient with ocular GVHD. The patient was administered with intensive topical preservative-free lubrication, topical preservative-free antibiotics, topical autologous serum 20%, topical non-preservative steroid (methylprednisolone 1%), and oral valacyclovir 1 g twice daily. The patient underwent amniotic membrane patch surgery on bulbar conjunctiva and cornea, lateral tarsorrhaphy, and punctal occlusion for the left eye. CONCLUSION: In this report, severe and extensive limbal ischemia caused by herpes zoster virus in an immunocompromised patient is reported.

Longitudinal evaluation of posterior corneal power by anterior segment optical coherence tomography 18 months following photorefractive keratectomy.

PURPOSE: To investigate the change in anterior, posterior, and net corneal power more than 18 months after photorefractive keratectomy (PRK) by RTVue anterior segment optical coherence tomography (OCT). SETTING: Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. DESIGN: Prospective observational study. METHODS: PRK was performed using Technolas TENEO 317 laser platform. Anterior, posterior, and net corneal power was measured by the RTVue-XR anterior segment OCT system with the Pachymetry + Cpwr scan pattern at baseline and months 1, 3, 6, 12, 18, and more than 18 (up to 27) after PRK. RESULTS: Three hundred twenty-six eyes of 163 patients (61 men [37.4%], 102 women [62.6%]; mean age 29.71 years; range 18.5 to 46.5 years) were enrolled in this study. Mean preoperative spherical equivalent was -3.15 ± 1.50 diopter (D) (range -8.37 to -0.62 D). The mean change in net corneal power was 3.052 D, 3.281 D, 3.324 D, 3.114 D, 3.446 D, and 3.972 D at months 1, 3, 6, 12, 18, and more than 18 postoperatively compared with baseline, respectively (P < .001 for all comparisons). The mean change in posterior corneal power at postoperative visits compared with baseline was not statistically significant (P > .1) except for 1 month postoperatively, which increased by 0.13 D (P < .001). Changes in posterior corneal power were not correlated with any of the preoperative clinical and Scheimpflug variables. CONCLUSIONS: Posterior corneal power did not change for more than 18 months after PRK, except for an early small increase at 1 month postoperatively.

Effects of Soft Toric, Rigid Gas-Permeable, and Mini-Scleral Lenses on Corneal Microstructure Using Confocal Microscopy.

OBJECTIVE: To determine effects of wearing soft toric silicone hydrogel, rigid gas-permeable (RGP), and mini-scleral lenses on corneal microstructure using confocal microscopy. METHOD: A prospective cohort study was conducted on 33 neophyte patients fitted with contact lenses (avg. age: 26±7 years) in the tertiary eye center. Patients were instructed to wear soft toric silicone hydrogel, RGP, or mini-scleral lenses based on clinical diagnoses. Inclusion criteria were age greater than 18 years and best-corrected visual acuity ≥3/10. Patients with a history of eye-involving systemic diseases were excluded. Baseline examinations included log of minimal angle of resolution visual acuity (Early Treatment Diabetic Retinopathy Study chart), refraction, slit-lamp, and fundoscopy. Confocal microscopy was used to measure subbasal nerve (SBN) density (mm/mm), keratocyte cell density (cells/mm), basal epithelial cell density (cells/mm), and endothelial cell density (cells/mm). Data were gathered on the first and follow-up visits. The follow-up visit happened after 6 months when the subjects had stopped wearing contact lenses for 12 hr. Comparative analysis was conducted within each group using the paired t test. RESULTS: The changes in visual acuity, SBN, and keratocyte cell density were insignificant after 6 months of wearing lenses in all three groups. The basal epithelial cell density significantly decreased (P<0.05) in RGP and mini-scleral groups. In addition, the endothelial cell density decreased significantly (P<0.05) in the RGP group. No significant changes were detected in soft toric silicone hydrogel lens wearers. CONCLUSIONS: Soft toric silicone hydrogel lenses seemed to have the least impact on the corneal cellular microstructure for a wear period of 6 months, controlling confounding factors of prior cross-sectional investigations. The coarse (three layers) versus fine (five layers) division of stroma, the repeatability and reproducibility of stromal layers' demarcation, and the cohort size and its diversity in terms of initial corneal diagnoses (particularly in the mini-scleral wearing group) can potentially influence the outcomes, and their impact remains to be further investigated.

Assessing the Validity of Measurements of Swept-source and Partial Coherence Interferometry Devices in Cataract Patients.

SIGNIFICANCE: The validity of measurements of OA-2000 (Tomey, Nagoya, Japan), a new swept-source optical coherence tomography-based biometer, was evaluated in comparison with IOLMaster 500 (Carl Zeiss Meditec AG, Jena, Germany) as a reference method for optical biometry in cataract patients. PURPOSE: This article compares the validity of measurements between OA-2000 and IOLMaster 500. METHODS: In this cross-sectional study, axial length, lens thickness, anterior chamber depth, and keratometry readings were obtained by the OA-2000 and IOLMaster 500. Two measurements were taken by each method. Patients in which any one of the biometry methods could not be performed owing to severity of the cataract were excluded from the study. Repeatability of measurements was presented by coefficient of variation, and Bland-Altman method was used for evaluating the agreement between the two biometers. RESULTS: Fifty-eight eyes of 58 cataract patients with mean ± standard deviation age of 61.4 ± 8.3 years were included in this study. Intraclass correlation ranged from 0.898 to 0.901 and showed good to excellent reliability. It was good for keratometry 1 (0.898) and excellent for keratometry 2 (0.992), axial length (0.999), and anterior chamber depth (0.901). Bland-Altman analysis showed good agreement between the swept-source optical coherence tomography and partial coherence interferometry devices for axial length, anterior chamber depth, and mean keratometry, with narrow 95% limits of agreement (-0.09 to 0.1 mm, -0.33 to 0.54 mm, -0.97 to 1.03 D, respectively), and also indicated small mean difference (0.01 for axial length, 0.11 for anterior chamber depth, 0.03 for mean keratometry, respectively) for all comparisons. CONCLUSIONS: OA-2000 as a new swept-source optical coherence tomography has an excellent repeatability for measurement of biometric data in cataract patients, comparing with the standard partial coherence interferometry biometer (IOLMaster 500).

Stromal Patch with fibrin glue as a novel surgical technique to seal peripheral Descemet's membrane perforations in deep anterior lamellar keratoplasty.

PURPOSE: The purpose of this article was to introduce a novel surgical technique for the management of peripheral Descemet's membrane perforation during deep anterior lamellar keratoplasty (DALK). METHODS: First, a thin stromal patch was prepared either from the anterior stromal lamella cut during DALK or from the anterior stroma of a Descemet's stripping automated endothelial keratoplasty button. The stromal patch was secured in a stromal pocket dissected deep in the trephination edge along the perforation site. Fibrin glue was applied to the stromal patch. Finally, the graft was sutured to the recipient bed. RESULTS: We used this technique in 3 cases with peripheral DM perforations during DALK. The first case was a persistent postoperative double anterior chamber who developed Urrets-Zavalia syndrome after air injection in an attempt to seal the perforation. In the second case, this technique was applied to seal an intraoperative DM perforation, without which the procedure would have been converted to penetrating keratoplasty. The third case had a persistent postoperative double chamber despite multiple air injections and fibrin glue application. The technique was effective in the management of all DM perforations with a resolution of double anterior chamber. CONCLUSION: This technique is safe and effective as an intraoperative method or a postoperative measure to seal peripheral DM perforations. We recommend this technique for repairing peripherally located DM perforations during DALK not amenable to simple measures like air injection or fibrin glue application.

3D-Printed membrane as an alternative to amniotic membrane for ocular surface/conjunctival defect reconstruction: An in vitro & in vivo study.

BACKGROUND: The aim of this study was to evaluate the surgical handling and clinical applicability of a specific 3D-printed membrane design fabricated using a gelatin, elastin and sodium hyaluronate blend for conjunctival reconstruction and compare it with amniotic membrane (AM), which is normally used in such surgeries. METHODS: 3D printing technique was employed to fabricate the membrane based on gradient design. Prior to printing, rheometry was employed to optimize the ink composition. The printed membranes were then fully characterized in terms of physical and mechanical properties. In vitro viability, proliferation and adhesion of human limbal epithelial cells were assessed using MTT assay and scanning electron microscopy (SEM), respectively. Prior to in vivo experiment, surgical handling of each membrane was evaluated by three surgeons. In vivo evaluation was conducted through implanting the gelatin-based membranes and AM on induced conjunctival defects in rabbits (n = 8). Clinical observations, including epithelialization, inflammation severity, scar tissue formation and presence of granulation tissue, were recorded from day 1 through day 28. Histological examination was performed on all enucleated eyes on day 28. In addition to H&E staining, specific stains including Periodic Acid Schiff staining, Masson's Trichrome staining and immuno-histochemical staining for α-SMA were further used to assess goblet cell proliferation, healed sub-epithelial stroma and scar tissue formation and the presence of myofibroblasts, respectively. RESULTS: Among all the examined compositions, a blend of 8% w/v gelatin, 2% w/v elastin and 0.5% w/v sodium hyaluronate was found to be appropriate for printing. The printed membranes had favorable optical characteristics (colorless and transparent), and the surgical handling was significantly easier compared to AM. Epithelial cells cultivated on the membranes indicated suitable viability and proliferation, and SEM images presented appropriate cell adhesion on the surface of the membranes. Clinical observations suggested similar epithelialization time (approximately 3 weeks) for both the membrane and AM grafted eyes but significantly lower levels of clinical inflammation in the membrane group from day 1 through day 28 (p = 0.01), which is a key advantage of using the printed membranes over the AM. Histological examination showed similar qualities in the healed epithelium in terms of cell morphology and cell layers. However, twice the density of goblet cells per 100 cells was observed in the gelatin-based membrane grafted group. Remnant of the degraded implant was seen in only 3 of the membranes, but in 7 of the AM grafted eyes. Inflammation and granulomatous reaction was significantly higher in sections containing the AM compared to membrane (p < 0.01 and p = 0.01, respectively). α-SMA staining was more evident, but not significantly different from the gelatin-based membrane, for the AM group (p = 0.25). CONCLUSION: The designed gelatin-based membrane offers the necessary physical and mechanical characteristics needed for successful ocular surface/conjunctival defect construction and may be considered a promising alternative to AM due to a more predictable degradation pattern, higher goblet cell density on the healed epithelium, less inflammation and reduced scar tissue formation.