Outflow resistance of enucleated human eyes at two different perfusion pressures and different extents of trabeculotomy.
Aqueous outflow resistance of enucleated human eyes was measured at 7 and 25 mm Hg before and after partial and complete (12 clock hours) internal trabeculotomy. Following complete trabeculotomy, 71% of the resistance was eliminated at 25 mm Hg while only 49% was eliminated at 7 mm Hg. In contrast to published findings in eyes with intact trabecular meshwork where the resistance increased with increasing IOP (1), following complete trabeculotomy, the resistance decreased 2% per mm Hg with increasing IOP. Experiments with trabeculotomy limited to part of the circumference showed that a one hour trabeculotomy produced 41% (25 mm Hg) to 60% (7 mm Hg) of the effect of a twelve hour trabeculotomy. The results indicate that a surprisingly high fraction of aqueous outflow resistance resides in the distal aspects of the outflow system at normal IOP, and that this distal resistance drops as IOP is increased.
Rosenquist
R
R
Howe Laboratory of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston.
Epstein
D
D
Melamed
S
S
Johnson
M
M
Grant
W M
WM
D000368:Aged; D000704:Analysis of Variance; D000867:Anterior Chamber / Q000378:metabolism; D001082:Aqueous Humor / Q000378:metabolism*; D015353:Eye Enucleation; D005260:Female; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D010477:Perfusion; D011312:Pressure; D014130:Trabeculectomy