Tear potassium contributes to maintenance of corneal thickness.
Isolated rabbit corneas were bathed on their endothelial surfaces with normal Krebs bicarbonate Ringer solution, while the epithelial surfaces were bathed in a basic tear solution containing sodium and potassium. When bathed in basic tear solution alone, corneal swelling occurred at an average of 12 microns/h over a 3-hour period. Corneal swelling occurred at a rate of about 21 microns/h when the epithelial solution was switched from normal basic tear solution to an iso-osmotic K(+)-free basic tear solution. Corneal swelling then slowed, and in the final hour of a 3-hour exposure to K(+)-free tear solution, the corneas deswelled at about 10 microns/h. The data indicate that potassium is a necessary solute for the maintenance of normal corneal thickness. The results suggest that a lacrimal dysfunction that would cause a decrease in the potassium content of tears may influence corneal thickness and also suggest that the inclusion of potassium in artificial tears is important.
Green
K
K
Department Ophthalmology, Medical College of Georgia, Augusta 30912-3400.
MacKeen
D L
DL
Slagle
T
T
Cheeks
L
L
D000818:Animals; D003315:Cornea / Q000473:pathology*; D015715:Corneal Edema / Q000473:pathology; D004848:Epithelium / Q000473:pathology; D009883:Ophthalmic Solutions; D010477:Perfusion; D011188:Potassium / Q000502:physiology*; D011817:Rabbits; D012964:Sodium / Q000502:physiology; D013666:Tears / Q000502:physiology*
D009883:Ophthalmic Solutions; D012964:Sodium; D011188:Potassium