The effects of local hypothermia on postoperative inflammation, electr
oretinogam (ERG) and histological changes of the retina were evaluated
in experimental vitrectomy in pressure-induced ischemic rabbit eyes.
The solutions used for intraocular perfusion were maintained at 8 degr
ees C, 22 degrees 6 or 38 degrees C. Following closed vitrectomy, the
vitreous cavities of the rabbit eyes were irrigated for 30 minutes wit
h the perfusion pressure set at 70 mmHg. The blood flow in the posteri
or area of the eye was reduced to about one-sixth of the preoperative
level during ischemia. Aqueous protein concentrations showed no signif
icant diversities among the different temperature groups on postoperat
ive days 1 and 7. Recovery of ERG was investigated after a given time
of ischemia. There were no significant differences in the recovery of
either a-wave or b-wave amplitudes among the different temperature gro
ups; although the average b-wave amplitude in the 38 degrees C group a
lone failed to return to the preoperative level on the 7th postoperati
ve day. Light microscopy showed an irregular distribution of retinal d
amage in all groups. The damaged regions showed significantly greater
histologic impairment in the 38 degrees C group than in either the 8 d
egrees C or 22 degrees C group. The results of our experiments suggest
that local hypothermia during vitrectomy in ischemic eyes decreases r
etinal damage and, therefore, it seems inadvisable to use intraocular
solutions warmed to body temperature.