Inma Perez-Gomez

A population study of the normal cornea using an in vivo, slit-scanning confocal microscope.

Purpose. To document qualitative and quantitative changes in the normal, healthy human cornea with age using the confocal microscope. Methods. The central corneas of 120 subjects (mean age, 41 years; range, 11 to 80 years) were examined using an in vivo slit-scanning real-time confocal microscope. Images of the corneal stroma and endothelium from both eyes of each subject were semiautomatically analyzed in an observer-masked, randomized manner. Results. Anterior keratocyte density, posterior keratocyte density, and endothelial cell density were shown to be unaffected by the sex of the subject with p values of 0.46, 0.55, 0.50, respectively (multivariate analysis of variance). No statistically significant difference was detected between right and left eyes for all corneal layers examined. The anterior keratocyte density, posterior keratocyte density, and endothelial cell density decreased at a rate of 0.48, 0.22, and 0.33% per year, respectively. A positive correlation was found between the coefficient of cell variation and age. Conclusions. This data constitutes essential normative data that can be used as a control in further research into abnormal corneal conditions.

Confocal microscopic observations of the human cornea following overnight contact lens wear.

Background: Striae and folds are observed with a slidamp biomicroscope in the cornea following overnight contact lens wear. These phenomena are poorly understood. The aim of this study is to employ confocal microscopy to observe and document these and other morphological changes in die human cornea following overnight contact lens wear.

Confocal microscopic observations of stromal keratocytes during extended contact lens wear.

Background: The aim of this study was to monitor changes in keratocyte density during extended contact lens wear and to explore the possible role of hypoxia and oedema in any changes observed.

Confocal microscopy of the normal human cornea

The slit-scanning confocal microscope is a new clinical paradigm that allows the living human cornea to be viewed at a magnification of 680 x and a lateral resolution of 1 mum. As such, it allows corneal morphology to be inspected at a cellular level. The corneas of both eyes of 119 subjects who were evenly distributed in age from 10-80 years were examined using a Tomey ConfoScan P4 in-vivo slit-scanning real-time confocal microscope (Erlangen, Germany). Good quality representative images of the various corneal layers were selected for detailed qualitative analysis and are displayed here. A grid of corneal layer versus age was constructed from these images; this tool can be used as a normative confocal microscopy reference against which suspected corneal abnormalities can be assessed.

Confocal microscopic evaluation of particles at the corneal flap interface after myopic laser in situ keratomileusis.

Purpose: To investigate the appearance and origin of interface particles in the cornea after myopic laser in situ keratomileusis (LASIK) using the confocal microscope. Setting: Department of Optometry and Neuroscience, UMIST, Manchester, United Kingdom. Methods: An in vivo slit‐scanning, real‐time confocal microscope (Tomey ConfoScan P4) fitted with an Achroplan® 40X/0.75 NA immersion objective (Zeiss) was used to examine the morphology of the central cornea in 6 patients (12 eyes) at the initial visit (before surgery) and 1 week and 1, 3, and 6 months after LASIK for myopia. Results: In all eyes, several interspersed particles of variable size and brightness were observed 1 week after surgery at the flap interface. The overall density of these particles decreased with time (F = 14.34, P = .01). For analysis, the particles were divided by density into high brightness and low brightness. The low‐brightness particles significantly decreased with time (F = 13.26, P = .02). The high‐brightness particles remained constant in density at all postoperative visits (F = 1.3, P = .15). Conclusions: The particles of low reflectivity may represent 1 or more types of remains. It is unclear whether the low‐reflectivity particles will eventually disappear. The high‐reflectivity particles may represent fine metallic debris arising from the mechanical drive mechanism and/or the disposable knife of the microkeratome. If they are metallic and magnetic, they could be cleared during surgery (immediately before flap replacement) using a specially adapted magnet.