Ophthalmoscopic, Ultrasonographic and Electrophysiologic Findings of Experimentally Induced Intraocular Pressure Increase in Rabbits

The aim of this study was to determine ophthalmoscopic, ultrasonographic and electrodiagnostic response of the experimentally induced increasing intraocular pressure (IOP) in 6 New Zealand rabbits. IOP was induced by cauterizing 3 vortex and 3 episcleral veins. The cases were evaluated by ophthalmoscopy, ultrasonography (USG), electroretinography (ERG) and visual evoked potentials (VEP). Significant elevation in intraocular pressure (IOP) was seen in all rabbits on the postoperative 1st day. Although IOP values did not significantly differ between treated and control eyes from the 2nd to the 4th week, exchange of cornea-anterior lens capsule and posterior lens capsule-retina measurements were persistent. In ERG, implicit time of a and b wave of the treated eyes increased significantly during 4 weeks, however, the amplitude of both waves were markedly lower than control eyes until the end of 2nd week. In VEP, the decrease in N1 wave amplitude was marked in 4th week. These results indicated that even though the increasing IOP came back to the normal limits, ERG and USG parameters did not return to baseline. As a result, in clinical cases, even if IOP return to normal limits after treatment, intraocular structures and the retina should be evaluated and treatment should be advanced in this direction.