Intraocular oxygen tension in eyes with proliferative diabetic retinopathy with and without vitreous.

BACKGROUND

Intraocular oxygen tension was measured in the eyes of patients with proliferative diabetic retinopathy with or without vitreous in order to determine local differences in tissue oxygenation in the vitreous cavity before and after vitrectomy.

METHODS

We measured oxygen tension, using polarographic oxygen electrodes, at various intraocular locations in 30 eyes of 29 patients with diabetic traction retinal detachment who were candidates for vitrectomy (pre-vitrectomy group) and 13 eyes of 13 diabetic patients who had previously undergone vitrectomy (post-vitrectomy group).

RESULTS

In the pre-vitrectomy group, oxygen tensions proximal to the neovascularization of the disc and the neovascularization elsewhere were significantly higher than the values obtained at other locations in the vitreous cavity. In the post-vitrectomy group, however, the oxygen tensions at those locations were significantly lower than those in the pre-vitrectomy group. There were no significant differences between the values obtained at any of the measurement locations in the post-vitrectomy eyes.

CONCLUSION

Neovascular tissues in the eyes of diabetic patients demonstrated higher oxygen tensions than non-neovascular tissues. This finding suggests that neovascular issue may compensate for intraocular hypoxia by releasing oxygen from the front. Successful diabetic vitrectomy reduces the activity of the neovascular tissue and equalizes levels of oxygenation in the tissue of the vitreous cavity.