NR 2/2011 ART. 09
Dr n. wet. Przemysław K. Bryła
Przychodnia weterynaryjna w Warszawie
Aqueous humor is produced by the ciliary body by active secretion and filtration of plasma. Most of the aqueous humor flows from the posterior chamber, through the pupil, to the anterior chamber, and exit at the iridocorneal angle into the intrascleral venous plexus. The balance between formation and drainage maintains intraocular pressure. In glaucoma the pressure in the eye increased. Prolonged or recurrent elevation of intraocular pressure lead to degeneration of the retina and optic nerve. The presence of a “red eye”, corneal edema, mydriasis, blepharospasm, blidness, and buphtalmos can be seen. Pupillary light reflex may be slow or absent.
Glaucoma is divided into primary (including congenital) and secondary categories. The iridocorneal angle may be open, narrow or closed in either type. The primary glaucoma in cats is a heredietary condition. Secondary glaucoma is more commonly encountered than primary. Secondary glaucoma is most frequently due to severe anterior uveitis or iris melanoma. The elevation of intraocular pressure results from other disease processes within the eye. Feline aqueous humor misdirection syndrome is a unique form of glaucoma seen in cats. Aqueous humor is misdirected posteriorly into the vitreous instead of anteriorly in the anterior chamber. The objectives of therapy are to maintain vision and eliminate pain by increasing aqueous outflow, decreasing aqueous production and preventing or delaying glaucoma in the other eye. Aggressive medical (topical beta-blockers and carbonic anhydraze inhibitor) and possibly surgical therapy ( YAG laser, partial vitrectomy or lens removing) is indicated if the eye still has vision. If the eye is reversibly blind enucleation procedures should be performed.