[Studies on intraocular hydrogen ion concentration. The effect of diathermy coagulation for normal albino rabbits'...

The vitreous and intra-retinal pH of anesthetized albino rabbits were measured using an antimony pH microelectrode (Micro Antimon pH Electrode No. 801, Diamond Electro-Tech Co. Ltd). The effect for the retinal pH was observed after regional choroidal circulatory disturbance was synthesized by trans-scleral diathermy. The results showed that the arterial blood pH was 7.45 +/- 0.03 (n = 24). The average vitreous pH was 7.41 +/- 0.11 (n = 24), which was almost equal to or slightly lower than that of the arterial blood. There were no statistical significance between the two. The average retinal pH was 7.31 +/- 0.11 (n = 22), which was lower statistically than that of the vitreous (p less than 0.01). The retinal pH was measured in the same way 3 weeks after the trans-scleral diathermy. Those within the coagulation scar showed pH value of 6.87 +/- 0.39 (n = 10). This is lower than those in a normal retina (p less than 0.01). This instrument allows continuous pH measurements of the intraocular tissue and therefore it is thought to be useful for the studies of retinal circulatory disturbances.