Dry eye and blink rate simulation with a pig eye model.

Purpose: To simulate medium level "dry eye" and investigate the effect of "blink" rates in "dry eye" condition using a novel porcine dry eye model (pDEM).

Methods: In the first experiment, a 40 s "lacrimation/blink" interval (lacrimation occurring in conjunction with blink) was set in the pDEM to simulate a medium level of "dry eye" condition. In the second experiment, "lacrimation" interval was set at 60 s and three different "inter-blink" intervals of 6, 12, and 20 s were set in groups A, B, and C, respectively.

Investigation of corneal effect of different types of artificial tears in a simulated dry eye condition using a novel porcine dry eye model (pDEM).

Purpose: To use a novel porcine dry eye model (pDEM) to study the effect of various artificial tears on corneal abrasion and epithelial cell death under severe "dry eye" conditions.

Methods: A 60-second lacrimation-blink interval, which simulates a severe dry eye condition, was set up with our novel pDEM. The corneal protective effect of lubricating the eye for 4 hours with Dulbecco phosphate-buffered saline (DPBS, as control; n = 20) and with 3 types of commercially available artificial tears (n = 17 for each) that contained different lubricating agents was studied.

UV-mediated DNA strand breaks in corneal epithelial cells assessed using the comet assay procedure.

Ultraviolet (UV)-mediated DNA damage in various tissues has been well documented. However, research on the damaging effect of UV irradiation on the DNA of corneal epithelium is scarce, even though this is of interest because the cornea is directly exposed to damaging solar (UV) radiation. In this study, we developed a corneal epithelium Comet assay model to assess the background DNA damage (as strand breaks) in cells retrieved from different layers of the porcine corneal epithelium, and to investigate the effect of UV irradiation on DNA damage in corneal epithelial cells.

Viability of porcine corneal epithelium ex vivo and effect of exposure to air: a pilot study for a dry eye model.

Purpose: To explore the use of an ex vivo, in situ porcine cornea as a model for dry eye (exposure keratitis).

Methods: Twenty-seven porcine eyes were obtained from freshly killed animals at the local abattoir. The viability of 9 corneas (control-baseline group) was assessed within 5 minutes after enucleation on site.

A novel porcine dry eye model system (pDEM) with simulated lacrimation/blinking system: preliminary findings on system variability and effect of corneal drying.

Purpose: To investigate inter- and intra-system variations and the effect of corneal drying using a recently developed pDEM.

Methods: pDEM was used to simulate "normal" and "dry eye" conditions using two "lacrimation-blink" intervals (20 s and 60 s). Corneas were examined/graded with sodium fluorescein before and after the experiment.

Effect of one overnight wear of orthokeratology lenses on tear composition.

Purpose: To evaluate the effect of one night of orthokeratology lens wear on ocular surface health based on the changes in tear components, including ascorbate, urate, lactate dehydrogenase (LD), lactoferrin, lipocalin, lysozyme, secretory immunoglobulin A (sIgA), and serum albumin.

Methods: Changes in tear components in eight healthy young men before and after 7-h overnight ortho-k lens wear were studied. Subjects attended on two separate occasions during a 1-week period, on one occasion wearing lens overnight and on the other wearing no lens.

Is ascorbate in human tears from corneal leakage or from lacrimal secretion?

Background: This study investigated whether fresh main lacrimal gland secretion contains ascorbate, with a view to providing indirect evidence of an immediate source of this antioxidant in tears. Our hypothesis was that, if the source is corneal leakage, continuous tearing or rinsing of the eye will result in a marked decrease, by dilution, in ascorbate concentration in the reflex tears collected. Alternatively, the ascorbate concentration will be relatively constant if the main lacrimal gland secretion is the main immediate source.