Regional Variations in Corneal Epithelial Cell Density and Morphology Assessed Using In Vivo Confocal Microscopy.

AIM: To characterize the regional variations in corneal epithelial cell density and morphology using in vivo confocal microscopy (IVCM). METHODS: Corneal imaging (IVCM) at 10 locations was performed; corneal apex (i.e., the center), immediately anterior to the corneal nerve whorl (i.e., slightly inferior to the apex), and four quadrants (superior, nasal, inferior, and temporal) both at 1.5 mm and 4.5 mm from the corneal apex (corresponding to 3 mm central and 9 mm peripheral diameter rings). The data of 21 young adults, aged 18 to 35 years, were analyzed. Cell morphometric parameters, including cell density, area, perimeter, Feret diameter, and circularity, were measured for basal and wing cells using Image J software. RESULTS: There was a significant difference in basal cell density (BCD) ( P <0.001) and wing cell density (WCD) ( P <0.001) for different corneal locations. The BCD (mean±SD: 8,839±416 cells/mm 2 ) and WCD (mean±SD: 5,932±310 cells/mm 2 ) were highest at the corneal nerve whorl compared with all other corneal locations. There were significant differences in wing cell area ( P <0.001), perimeter ( P <0.001), Feret diameter ( P <0.001), and circularity ( P <0.001) at varying corneal locations. CONCLUSION: There are significant regional variations in corneal epithelial cell density and morphology. The BCD and WCD was highest anterior to the corneal nerve whorl.

Corneal Epithelial Cell Density Is Reduced in Young Adults With Conjunctival Ultraviolet Autofluorescence.

PURPOSE: The aim of this study was to investigate the effects of chronic ultraviolet (UV) radiation exposure on the corneal microstructure using conjunctival UV autofluorescence (CUVAF) as a marker of exposure. METHODS: Young healthy adults aged 18 to 35 years were recruited. Participant's demographics and sun exposure behavior were recorded using questionnaires. Images of the bulbar conjunctiva from the right eye were captured and analyzed for the CUVAF area. Corneal microstructure was assessed by in vivo confocal microscopy and anterior segment optical coherence tomography. The presence of palisades of Vogt in all 4 limbal quadrants was recorded. RESULTS: CUVAF was observed in 31 of 52 eyes (60%), with a mean (±SD) nasal, temporal, and total CUVAF area of 5.39 ± 4.16 mm2, 4.29 ± 4.27 mm2, and 9.67 ± 7.01 mm2, respectively. Individuals with CUVAF were significantly more likely to report undertaking moderate-intensity to high-intensity outdoor exercise (P = 0.021). Individuals with CUVAF were less likely to have visible nasal and temporal palisades of Vogt (P = 0.011). Corneal basal cell densities anterior to the nerve whorl (P < 0.001) and nasally (P = 0.005) were lower in individuals with CUVAF. Wing cell density anterior to the nerve whorl was lower in individuals with CUVAF (P = 0.011). No significant changes in the central and limbal corneal epithelial thickness were observed. CONCLUSIONS: Significant reductions in corneal epithelial cell density were observed in individuals with CUVAF, a biomarker of chronic UV exposure. This observation suggests that chronic UV exposure is damaging to the corneal microstructure.

Segmentation methods and morphometry of confocal microscopy imaged corneal epithelial cells.

PURPOSE: To develop and explore automated cell identification and segmentation methods for morphometry of confocal microscopy imaged corneal epithelial cells using ImageJ software. METHODS: In vivo confocal microscopy images of the intermediate (wing) and basal cell layers of the central and peripheral corneas of 20 healthy participants were analysed. The intermediate and basal cell areas obtained using the two new techniques (i.e., manual- and auto- thresholding) were compared with the widely used manual tracing technique. A predefined range of epithelial cell morphometric parameters was used as image descriptors to improve cell identification and segmentation. RESULTS: The mean intermediate cell area obtained using the manual tracing (central; 120 ± 14 µm2, peripheral; 123 ± 15 µm2) was statistically similar (p > 0.05) to the manual thresholding (central; 119 ± 7 µm2, peripheral; 119 ± 8) but not with the auto thresholding technique (central; 101 ± 8 µm2, peripheral; 101 ± 7 µm2). Bland-Altman limits of agreement for the mean difference (measurement bias) in central and peripheral intermediate cell area determined via manual tracing and manual thresholding techniques were 1 µm2 (+25 to - 23 µm2) and 4 µm2 (+29.8 to - 21.9 µm2). There were statistically significant differences in basal cell area between the three methods. CONCLUSION: The manual thresholding technique may be used for automated identification and segmentation of corneal epithelial intermediate cells (central and peripheral) for assessing various morphometric parameters. However, measurement of the corneal epithelial basal cells is less reliable using thresholding techniques.

Central corneal basal cell density and nerve parameters in ocular surface disease and limbal stem cell deficiency: a review and meta-analysis.

OBJECTIVE: To conduct a review and meta-analysis for investigating the relative reduction of central corneal basal cell density (BCD) and nerve parameters in ocular surface disease (OSD) and limbal stem cell deficiency (LSCD). METHODS: A systematic literature search using the terms ((1) "ocular surface disease" or "ocular surface disorder"; (2) "in vivo confocal microscopy"; (3) "limbal stem cell deficiency"; (4) "basal cell density" or "corneal basal cell density" or "central corneal basal cell density"; (5) "corneal nerves" or "corneal nerve parameters" or "central corneal nerve parameters") was performed. The results are presented as weighted mean difference (WMD) with corresponding 95% CI. RESULTS: 16 studies that reported the central corneal BCD and 21 studies that reported the central corneal nerve parameters in OSD (including LSCD) were included. A significant reduction in central corneal BCD was observed in patients with various OSDs (WMD=-9.50, 95% CI -14.04 to -4.97, p<0.01) as well as in patients with LSCD (WMD=-22.14, 95% CI -37.91 to -6.37, p<0.01) compared with healthy controls, however, no significant difference in BCD was observed between the two groups (WMD=-11.61, 95% CI -15.96 to -7.26, p=0.13). There was no conclusive difference in various central corneal nerve parameters between OSDs and LSCD. CONCLUSION: Central corneal BCD and nerve parameters are reduced in LSCD, there is a similar reduction in other OSDs.

Case Report: Post-keratoplasty Filamentary Keratitis Managed with Scleral Lens.

SIGNIFICANCE: This case report details a unique case of filamentary keratitis after penetrating keratoplasty managed with a scleral contact lens. The positive effect on vision and comfort are reported, and the challenges related to hypoxia are discussed. PURPOSE: The purpose of this study was to report the outcome of scleral lens use in the treatment of filamentary keratitis post-penetrating keratoplasty. CASE REPORT: A patient who underwent penetrating keratoplasty twice in both eyes for keratoconus presented with filamentary keratitis in the left eye. The prosthetic replacement of the ocular surface ecosystem scleral lens trial was performed for improving vision and comfort. After 6 hours of wearing prosthetic replacement of the ocular surface ecosystem device, the left eye showed complete resolution of filaments with an improved visual acuity and better comfort in both eyes. Corneal swelling indicating hypoxia was noticed in both eyes with scleral lenses and was managed accordingly. CONCLUSIONS: Scleral lenses are a viable treatment option for patients with corneal filamentary keratitis after penetrating keratoplasty for achieving better vision and improved comfort. However, the risk of hypoxia cannot be undermined, which necessitates careful evaluation, follow-up, and management for safe lens wear.

Does Occupation Influence Selection of Contact Lens Material?

OBJECTIVE: Long-term follow-up of contact lens (CL) wearers leads to better understanding of the factors leading to changes in CL trends. This study is an attempt to ascertain these factors in an emerging market like India. Factors like occupation were analyzed to determine if these contributed to changes in selection of CL materials in this article. METHODS: Occupations were categorized as per the norms of International Standard Classification of Occupations-2008 (International Labor Organization, United Nations organization). RESULTS: A majority of lens wearers were professionals and hydrogel lens materials were the lenses of choice among most of the lens wearers. There was a significant variation in CL material with different occupations (χ=19.29, P=0.037). CONCLUSION: To conclude, employment and affordability influenced the selection of lens materials.

Quality of life and handling experience with the PROSE device: an Indian scenario.

BACKGROUND: PROSE (prosthetic replacement of ocular surface ecosystem) device is a custom-designed, corneal vaulting scleral contact lens, which is used in the treatment of irregular corneal conditions to improve vision and comfort. The present study aimed at assessing the success of the PROSE device in an Indian scenario in terms of change in quality of life and to understand the handling issues related to the device use. METHODS: Thirty-two subjects with various irregular corneal conditions meeting the inclusion criteria were included in the study. Subjects were followed for three months after dispensing the PROSE device. Subjects' demographic details, high and low contrast visual acuity with habitual correction and PROSE device, Visual Function Questionnaire scores (NEI VFQ-25) and Ocular Surface Disease Index (OSDI) scores pre- and post-PROSE treatment were collected and compared. An indigenously developed questionnaire was also administered during the follow-up visit for assessing the handling-related issues faced by the subjects while using the device. RESULTS: Forty eyes of 32 subjects were included in the study, of whom 30 reported for follow-up. The median NEI VFQ-25 score improved from 47.33 points to 77.27 points over a period of three months, which was statistically significant (p < 0.05). There was a statistically significant decrease in median OSDI score from 51.14 points to 13.63 points post-PROSE treatment (p < 0.05). Subjects reported no or very minimal handling-related difficulties associated with the use of the PROSE device. CONCLUSION: The PROSE treatment can be an effective mode of managing patients with irregular corneal conditions and significantly improved the vision-related quality of life of patients suffering from these conditions. The handling of the device is easy and can be mastered with adequate training.

Multiple-injection thoracic paravertebral block as an alternative to general anaesthesia for elective breast surgeries: A randomised controlled trial.

BACKGROUND: General anaesthesia is currently the conventional technique used for surgical treatment of breast lump. Paravertebral block (PVB) has been used for unilateral procedures such as thoracotomy, breast surgery, chest wall trauma, hernia repair or renal surgery. METHODS: We compared unilateral thoracic PVB with general anaesthesia (GA) in 60 consenting ASA physical status I and II female patients of 18-65 years age, scheduled for unilateral breast surgery. Patients were randomly assigned into two groups, P (n=30) or G (n=30), to receive either PVB or GA, respectively. RESULTS: The average time to first post-operative analgesic requirement at visual analogue scale score≥4 (primary endpoint) was significantly longer in group P (303.97±76.08 min) than in group G (131.33±21.36 min), P<0.001. Total rescue analgesic (Inj. Tramadol) requirements in the first 24 h were 105.17±20.46 mg in group P as compared with 176.67±52.08 mg in group G (P<0.001). Significant post-operative nausea and vomiting requiring treatment occurred in three (10.34%) patients of the PVB group and eight (26.67%) patients in the GA group. CONCLUSION: The present study concludes that unilateral PVB is more efficacious in terms of prolonging post-operative analgesia and reducing morbidities in patients undergoing elective unilateral breast surgery.