The permeability of the cornea to drugs is clinically important because it is the major factor determining the efficacy of topically applied ophthalmic preparations. With this perspective, the present article gives a brief update and overview of corneal structure and proposed mechanisms of permeation. Physiological, physicochemical and formulation factors affecting drug permeation through corne...

BACKGROUND Diagnostic tests for dry eye disease (DED), including ocular surface disease index (OSDI), tear breakup time (TBUT), corneal fluorescein staining, and lissamine staining, have great deal of variability. We investigated whether fluorophotometry correlated with previously established DED diagnostic tests and whether it could serve as a novel objective metric to evaluate DED. METHODS ...

BACKGROUND Vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) induces both angiogenesis and vascular permeability. Although its angiogenic activity has been well characterized, the signaling pathways of VEGF-induced permeability remain poorly understood. METHODS AND RESULTS Using the mouse corneal micropocket assay, Miles assay, and a combination of cytochemical, elect...

PURPOSE To introduce an image analysis of the cornea in photorefractive keratectomy (PRK) for preoperative and early postoperative determination of changes in the condition of the cornea. METHODS Slit-lamp videography was used to evaluate the cornea. Microdensitometry of the corneal images was performed. The optic density of the anterior, middle, and posterior corneal layers was measured. Pho...

A water permeability study of the isolated cat corneal endothelium was performed with the use of a newly designed Lucite chamber and modified experimental methods. The hydraulic conductivity of the cat endothelium was 9.3 ± 1.09 x 10~ cm. seer atmr. The Staverman reflection coefficient to NaCl of cat endothelium was 0.6. It was determined that the resistance to the passage of either water or sm...

The corneal endothelial permeability coefficient (Pac) for fluorescein and fluorescein glucuronide was determined in ten normal young volunteers. After oral administration of fluorescein, the apparent concentrations of both dyes in the corneal stroma and the anterior chamber were measured by differential fluorometry. The apparent dye levels calculated directly from the in vivo fluorometric meas...

Osmotically driven water flow across the corneal epithelium and endothelium has been measured as a function of temperature. For both membranes deviations from a single straight-line relationship are found in a logarithmic plot of hydraulic conductivity against 1/T. Both membranes show a high (14 to 16 kcal per mole) apparent activation energy at temperatures between 23 degrees C. and 5 degrees ...

Sixteen patients enrolled in the PERK study were evaluated by fluorophotometry 24 hours or six months following radial keratotomy. A comparison of eyes operated and not operated upon showed that endothelial permeability was not significantly altered 24 hours and six months after surgery. Aqueous humour flow rates and anterior chamber elimination coefficients were significantly higher 24 hours a...