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Several growth factors have been evaluated for their effects on corneal wound healing but few studies have yet demonstrated an acceleration of endothelial repair in vivo. Mesodermal Growth Factor (MGF) was tested in vivo by making standardized freeze wounds in cat corneas and immediately injecting one of four concentrations of MGF in sterile phosphate buffered saline (PBS), or PBS alone, into the anterior chamber. Seven days later, the animals were sacrificed and the corneas excised and stained. Descemet's membrane and endothelium were dissected and mounted onto glass slides. The wound areas were photographed, measured and compared statistically. Those cats receiving the three lowest doses of MGF had significantly smaller wounds than controls (p less than 0.05).

Contact lenses may induce short- and long-term corneal endothelial changes. The endothelial bleb response is a short-term, reversible change noted with contact lens wear. Long-term endothelial changes such as polymegethism (increased variation in cell size) and pleomorphism (a decrease in the frequency of hexagonal cells) have also been detected in polymethylmethacrylate, rigid gas permeable, and daily and extended wear soft contact lens patients. These morphometric changes have also been seen in myopes, aphakes, and corneal transplant recipients. Differences in endothelial morphometry between the central and mid-peripheral regions of the cornea have also been noted in hard lens wearers. The long-term significance of these findings is discussed.

Vasoconstrictors such as phenylephrine and naphazoline are used in ophthalmology to decrease hyperemia associated with allergic conjunctivitis and contact lens wear. There is a suspicion, however, that chronic use of these agents can produce dry-eye symptoms in some patients. The purpose of this study was to determine whether vasoconstrictor use interferes with tear film adequacy by decreasing mucin-secreting goblet cells. Cellulose acetate filter strip impressions were taken from the bulbar conjunctiva of rabbit eyes treated with vasoconstrictors or artificial tears for varying periods of time, and the number of goblet cells per light microscopic field counted. There was no significant difference between the number of goblet cells in control and vasoconstrictor-treated animals within each time period. These results indicate that conjunctival goblet cell density is not significantly affected by topical vasoconstrictor use.

We examined the morphologic characteristics of the corneal endothelium in three groups of contact lens wearers: those who had used daily-wear soft contact lenses for an average of 6.3 years, long-term (greater than 20 years) users of hard contact lenses, and former users of hard contact lenses who had worn them for an average of 9.6 years but who had discontinued them for an average of 4.3 years. When compared to age-matched controls, all groups had similar endothelial cell densities but demonstrated significant increases in variation of cellular size (polymegethism) and shape (pleomorphism). We found that daily-wear soft contact lenses can cause endothelial polymegethism and pleomorphism similar to those caused by hard contact lenses and that the endothelial changes induced by hard contact lenses are more profound with greater duration of wear and are apparently not completely reversible.