Non-contact specular microscopy with Topcon instruments to assess central corneal thickness of healthy human eyes – A 20 year review

Doughty, Michael J.

doi:10.1016/j.clae.2020.11.005

Cited by 5 publications

(3 citation statements)

References 71 publications

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“…This study confirmed the long-term in vivo safety, biocompatibility and functionality of the LiQD Cornea implanted in two eyes of two animals, one with a corneal perforation and the other without perforation. The feline model, the third model on which the LiQD Cornea was tested, presents interesting complementary advantages over the traditional pig and rabbit models previously used, including closer similarities to human corneas in biomechanical properties and thickness (human: 546 ± 41 μm; feline: 583 ± 54 μm; domestic pig: 878 ± 14 μm; minipig: 704 ± 22 μm; rabbit: 387 ± 20 μm) ( Dohadwala et al, 1998 ; Shildkrot et al, 2005 ; Sanchez et al, 2011 ; Wang and Wu, 2013 ; Chen et al, 2015 ; Telle et al, 2019 ; Doughty, 2021 ). Like human corneas, the feline corneal stroma does not swell much, unlike that of the pig.…”

Section: Discussionmentioning

confidence: 99%

A Liquid Hydrogel to Restore Long Term Corneal Integrity After Perforating and Non-Perforating Trauma in Feline Eyes

Juárez

Djallali

Piché

et al. 2021

Front. Bioeng. Biotechnol.

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Purpose: To evaluate long-term in vivo functionality of corneas regenerated using a cell-free, liquid hydrogel filler (LiQD Cornea) after deep corneal trauma in the feline model.Methods: Two healthy cats underwent 4 mm diameter stepwise 250/450 µm deep surgical corneal ablation with and without needle perforation. The filler comprising 10% (w/w) collagen-like peptide conjugated to polyethylene glycol (CLP-PEG) and 1% fibrinogen and crosslinked with 2% (w/w) 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM), was applied to the wound bed previously coated with thrombin (250 U/ml). In situ gelation occurred within 5 min, and a temporary tarsorrhaphy was performed. Eyes were examined weekly for 1 month, then monthly over 12 months. Outcome parameters included slit-lamp, Scheimpflug tomography, optical coherence tomography, confocal and specular microscopy, and immunohistochemistry studies.Results: The gelled filler was seamlessly incorporated, supporting smooth corneal re-epithelialization. Progressive in-growth of keratocytes and nerves into the filler corresponding to the mild haze observed faded with time. The regenerated neo-cornea remained stably integrated throughout the 12 months, without swelling, inflammation, infection, neovascularization, or rejection. The surrounding host stroma and endothelium remained normal at all times. Tomography confirmed restoration of a smooth surface curvature.Conclusion: Biointegration of this hydrogel filler allowed stable restoration of corneal shape and transparency in the feline model, with less inflammation and no neovascularization compared to previous reports in the minipig and rabbit models. It offers a promising alternative to cyanoacrylate glue and corneal transplantation for ulcerated and traumatized corneas in human patients.

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Section: Discussionmentioning

confidence: 99%

A Liquid Hydrogel to Restore Long Term Corneal Integrity After Perforating and Non-Perforating Trauma in Feline Eyes

Juárez

Djallali

Piché

et al. 2021

Front. Bioeng. Biotechnol.

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“…10 Another parameter that could be obtained by specular microscopy imaging is the central corneal thickness (CCT) which is the true indicator of whether corneal decompensation has initiated. 11 Less-indicative parameters in the machine's output include the standard deviation (SD) from the average cellular area (AVG), and the maximum (MAX) and minimum (MIN) number of cells that can be automatically counted in a single eld. 10 Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been responsible for the recent coronavirus disease 2019 (COVID-19) pandemic.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Corneal Endothelial Cell Parameters Using Specular Microscopy in Previously Infected SARS-CoV-2 Patients

Elshalkami,

Abdalla,

Abdellatif

et al. 2023

QJM: An International Journal of Medicine

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Purpose To assess the effects of severe acute respiratory syndrome coronavirus 2 (SARS CoV 2) infection on the endothelium of the cornea. Methods A cross-sectional, comparative study with subjects previously infected by SARS CoV 2 infection for not less than six months (group 1) and a group of sex and age-matched controls without previous infection of SARS CoV 2 (group 2). Endothelial cell parameters were examined using specular microscopy. Following full ophthalmologic examination the groups were matched with controls of the same sex and age with no prior ocular surface pathologies. Results 64 and fifty-three right eyes were examined in both groups one and two, respectively. Between the 2 groups no differences in any of the examined specular parameters were detected that are statistically significant. Conclusion No delayed effects on the corneal endothelium appear to be caused by SARS CoV 2 infection. Further studies comparing the same subject before and after infection will be of significance.

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“…Specular microscopy has been established as a reliable means of examining the corneal endothelium in ophthalmological practice [ 19 ]. This non-invasive photographic technique allows visualization and qualitative and quantitative analysis of the endothelial layer [ 20 ].…”

Section: Introductionmentioning

confidence: 99%

Correlation between ocular biometric parameters and corneal endothelium in a sample of young Egyptian adults

Hamza¹,

Roshdy²,

Seleet³

et al. 2021

Med Hypothesis Discov Innov Ophthalmol

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Background: To evaluate the normative values of corneal endothelial cell parameters within a group of healthy young Egyptian adults using specular microscopy and to examine any correlations between endothelial parameters and refractive or biometric parameters.Methods: In this cross-sectional study, specular microscopy was used to study the right eyes of 150 healthy young volunteers and evaluated endothelial cell parameters, including cellular density, hexagonality (HEX), and coefficient of variation (CV) at 15 different points on the back corneal surface, which were later grouped into the central zone and either four quadrants or three annular zones. The same eyes underwent refractive and biometric assessments.Results: Hundred fifty healthy adults were examined, and the age ranged from 20 to 30 years, with a median of 23 (interquartile range, 21?27) years. The mean ± standard deviation of central cell density was 2902.7 ± 270.7 cells/mm2. The superior paracentral area had the lowest mean density (2895.8 cells/mm2), but the highest mean HEX (67.7%), while the inferior peripheral area had the highest mean density (3100.5 cells/ mm2) but the lowest mean HEX (64%). The difference in cell density among the three annular zones was not statistically significant (P = 0.365). However, HEX and CV in the central and paracentral zones differed statistically significantly from those of the peripheral zone (P < 0.001 and P = 0.014, respectively). Weak but non-significant correlations were detected between endothelial cell density and all measured refractive and biometric parameters.Conclusions: The findings of this study provided useful normative biometric and specular data in a specific age group and a specific population, and could be useful in planning intraocular surgery in young Egyptian adults. However, future longitudinal studies with a larger sample could refine more endothelial cell parameter specifications over time.

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Non-contact specular microscopy with Topcon instruments to assess central corneal thickness of healthy human eyes – A 20 year review

Cited by 5 publications

References 71 publications

A Liquid Hydrogel to Restore Long Term Corneal Integrity After Perforating and Non-Perforating Trauma in Feline Eyes

A Liquid Hydrogel to Restore Long Term Corneal Integrity After Perforating and Non-Perforating Trauma in Feline Eyes

Assessment of Corneal Endothelial Cell Parameters Using Specular Microscopy in Previously Infected SARS-CoV-2 Patients

Correlation between ocular biometric parameters and corneal endothelium in a sample of young Egyptian adults

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