Tianyu Zheng

An in vivo confocal microscopy and impression cytology analysis of goblet cells in patients with chemical burns.

PURPOSE To evaluate goblet cell density (GCD) on conjunctiva and cornea in patients with ocular chemical burns by in vivo laser scanning confocal microscopy (LSCM) and impression cytology (IC) and to explore the correlation between two methods. METHODS Fifty-four patients (58 eyes) with chemical burn were enrolled in the study. LSCM was applied to identify the goblet cells on conjunctiva and cornea under in vivo conditions, and GCD was analyzed with the customized software. Impression cytology was then performed, and the biopsy specimens were stained to visualize goblet cells in vitro and to measure the density. Statistical software was used to analyze the correlation between GCD taken by two methods. RESULTS Conjunctival goblet cells could be discriminated in 55 eyes and 57 eyes by in vivo LSCM and IC. They could be identified on the cornea in nine eyes and eight eyes by two methods. The positive rate of two methods had no significant difference. GCDs on conjunctiva measured by in vivo LSCM and IC were 136 +/- 79 cells/mm(2) and 121 +/- 66 cells/mm(2). Median GCDs on cornea detected by two methods were 30 cells/mm(2) and 23 cells/mm(2), respectively. A significant positive correlation was found between the GCDs on conjunctiva measured by these two methods as well as the GCDs on cornea. CONCLUSIONS GCD decreased in patients with chemical burns. A positive correlation was found between GCD measured by in vivo LSCM and IC after chemical burns. In vivo LSCM was a promising device to study goblet cells in vivo under pathologic conditions.

In Vivo Confocal Microscopic Evaluation of Morphologic Changes and Dendritic Cell Distribution in Pterygium

PURPOSE To observe morphologic changes and the distribution of dendritic cells in pterygium using in vivo laser scanning confocal microscopy (LSCM). DESIGN Prospective comparative study. METHODS Twenty-six eyes of 26 patients with pterygium and 17 eyes of 17 healthy subjects were recruited. Using LSCM, in vivo images of the pterygium and adjacent clear cornea were captured. The density of basal corneal epithelial cells and keratocytes in the anterior and posterior stroma and the density of dendritic cells in the pterygium and adjacent clear cornea were determined. In the controls, the central cornea and nasal bulbar conjunctiva were imaged. The density of basal corneal epithelial cells, keratocytes, and dendritic cells was evaluated. RESULTS Morphologic alterations of the sub-basal nerve plexus were observed in pterygium. The density of basal corneal epithelial cells and anterior keratocytes in pterygium was 5359.0 ± 543.1 cells/mm² and 407.4 ± 188.7 cells/mm² respectively, which was significantly lower than that in the controls (P < .001). The density of dendritic cells in the clear corneas of pterygia was 60.3 ± 25.5 cells/mm², which was significantly higher than the 23.6 ± 11.1 cells/mm² in the central corneas of controls (P < .001). The dendritic cell density in the pterygium was significantly higher than the density in the nasal bulbar conjunctiva of controls (P < .001). CONCLUSIONS Histopathologic alterations and increased dendritic cells were evident in pterygium and the adjacent clear cornea by in vivo LSCM. In vivo LSCM was found to be an effective method of observing the morphologic alterations of pterygium.

Influence factors of estimation errors for total corneal astigmatism using keratometric astigmatism in patients before cataract surgery

Purpose To evaluate the influence factors of the estimation errors for total corneal astigmatism using keratometric astigmatism in patients preparing for cataract surgery. Setting EYE and ENT Hospital of Fudan University, Shanghai, China. Design Prospective observational study. Methods Eyes of patients preparing for cataract surgery were measured with Pentacam Scheimpflug imaging device. Keratometric astigmatism was obtained using the anterior corneal surface measurement and the keratometric index (1.3375) while neglecting the posterior corneal surface measurement. The Scheimpflug‐measured total corneal astigmatism was derived by vector analysis of the astigmatism on both corneal surfaces. Results The study comprised 374 eyes of 374 patients 45 to 84 years old. The mean absolute error in magnitude and mean absolute error in angle comparing keratometric astigmatism with Scheimpflug‐derived astigmatism was 0.18 ± 0.14 diopter (D) and 7.7 ± 11.0 degrees, respectively. The mean magnitude of the error vector was 0.24 ± 0.14 D. The error in magnitude was significantly larger in eyes with against‐the‐rule anterior astigmatism, while error in angle was larger in eyes with with‐the‐rule and oblique anterior astigmatism. Multiple regressions showed that 4 predictors (difference in anterior–posterior astigmatism axis, magnitude of posterior astigmatism, magnitude of keratometric astigmatism, and axial length [AL]) were significantly associated with the absolute error in magnitude. Predictors including the difference in the anterior–posterior astigmatism axis, magnitude of posterior astigmatism, magnitude of keratometric astigmatism, and age were significantly associated with the absolute error in angle and magnitude of the error vector. Conclusions Neglecting posterior corneal astigmatism yielded significant estimation errors in total corneal astigmatism in patients preparing for cataract surgery. Estimation errors were significantly influenced by the difference in the anterior ‐posterior astigmatism axis, magnitude of posterior astigmatism, keratometric astigmatism, AL, and age. Financial Disclosure None of the authors has any conflicts of interest to disclose.

Comparison of human corneal cell density by age and corneal location: an in vivo confocal microscopy study

BackgroundPeripheral and central regions of the cornea are optically different and have different repair capacity and pathology. For this reason, we characterized the cellular morphology and quantified the cell density of the central and peripheral regions of the cornea with age.MethodsEighty healthy subjects were enrolled in the study and divided into four groups according to age: A (0–19 years), B (20–39 years), C (40–59 years), and D (>60 years). In vivo confocal microscopy was used to measure the following parameters for the central and peripheral regions of the cornea: average cellular density and area of the superficial and basal epithelium; average density of the anterior and posterior keratocytes; average endothelial cell density and cellular area; percentage of hexagonal endothelial cells.ResultsStatistically significant differences between the central and peripheral cornea were observed for the cellular density of basal epithelial cells in group A. The density of keratocytes in the anterior stroma was significantly greater in the central region compared with the peripheral region in group B and group C. The percentage of hexagonal cells in the endothelial layer was significantly greater in the central region compared with the peripheral region. Age-related changes were found in peripheral basal epithelial cell density, central and peripheral endothelial cell density, and the percentage of hexagonal endothelial cells.ConclusionBoth similarities and differences in morphology of the central and peripheral regions of the transparent cornea were observed. These observations would provide a histological basis for further studies to define its regional pathological mechanisms.

Near-term analysis of corneal epithelial thickness after cataract surgery and its correlation with epithelial cell changes and visual acuity

Purpose To quantify corneal central epithelial thickness and cell changes 2 weeks after cataract surgery and correlate it with corrected distance visual acuity (CDVA). Setting Eye and ENT Hospital of Fudan University, Shanghai, China. Design Prospective observational study. Methods Patients having cataract surgery were assessed preoperatively and 1, 2, 3, 5, 7, and 14 days postoperatively. Anterior segment spectral‐domain optical coherence tomography and corneal confocal laser scanning microscopy were used to measure central epithelial thickness, central corneal thickness (CCT), corneal basal epithelial cell density, and Langerhans cell density. Results The CCT and central epithelial thickness were significantly increased on 1 day postoperatively. From 1 day to 14 days, the CCT gradually decreased but was greater than the baseline value, whereas the central epithelial thickness declined to near baseline values at 3 days, became thinner at 5 and 7 days, and then returned to baseline at 14 days. The corneal basal epithelial cell density increased significantly postoperatively. Significant Langerhans cell infiltration was seen at 3 days and 5 days. Significant correlations were found between CDVA and the central epithelial thickness and CCT. The maximum increase in central epithelial thickness and CCT correlated with the lowest achieved values of CDVA postoperatively. Patients with significant edema at 1 day had worse CDVA at 14 days. Conclusions Near‐term epithelial remodeling occurred, initially appearing as a thickening that might be attributed to edema. This was followed by thinning, possibly caused by inflammation, and finally reaching baseline levels. Edema of the corneal epithelium was related to visual recovery after cataract surgery. Financial Disclosure None of the authors has a financial or proprietary interest in any material or method mentioned.