Abstract
Purpose:
To determine the intraocular distribution of oxygen tension and temperature in the various retinal diseases.
Methods:
Oxygen tensions (pO2) and temperatures were measured before vitrectomy at sites in the mid-anterior chamber (AC), in the anterior chamber angle, in the mid-vitrous cavity, and at the inner retina surface using an fiber-optic oxygen/temperature sensor (Oxylab pO2/Temp Optode; Oxford Optronix, Oxford, UK) in 8 subjects with proliferative diabetic retinopathy (PDR) who had developed recurrent vitreous hemorrhage, 17 subjects with rhegmatogenous retinal detachment (RRD), and 19 subjects with epiretinal membrane (ERM). In addition, 9 subjects with intravitreal silicone oil and 4 subjects with pseudophakia were included in this study.
Results:
The mean pO2 in the mid-vitreous in PDR (16.99 ± 8.22 mmHg) was significantly higher than those in ERM (6.66 ± 3.39 mmHg) (P=.027). The mean pO2 in the mid-AC and at the inner retina surface in RRD were 13.77 ± 5.95 and 4.81 ± 2.95 mmHg, which were significantly different from those in ERM (5.30 ± 4.46 and 10.24 ± 3.18 mmHg) (P=.037 and .001). The mean pO2 in the mid-vitreous and inner retina surface in silicone oil filled eyes were 8.63 ± 2.45 and 8.76 ± 2.37 mmHg, which were not significantly different from those in ERM (P=.052 and .493). However, the mean pO2 in the mid-AC (15.03 ± 2.81 mmHg) and in the mid-vitreous (16.88 ± 1.0 mmHg) in pseudophakia were significantly higher than those in ERM (5.30 ± 4.46 and 6.66 ± 3.39 mmHg) (P=.006 and .025). The mean temperature in the mid-AC, the AC angle, the mid-vitreous, and at the near inner retina were respectively 28.99 ± 1.28, 28.70 ± 3.24, 31.97 ± 1.20, and 33.73 ± 1.36 °C, and those were significantly different from each other (P<.002).
Conclusions:
We identified high intraocular oxygen tension, especially in the mid-vitreous in PDR with recurrent vitreous hemorrhage. Although our findings are not consistent with the previous reports that the intravitreal oxygen tension in PDR was lower than control, we suggest that recurrent vitreous hemorrhage and elevated VEGF would induce the massive neovascular complexs in the retina and then paradoxically could increase the intravitreal oxygen tension. Additionally, the pO2 in the silicone filled eye was not different from the control in this study and we confirmed significant intraocular temperature gradient in the various retinal diseases.
Keywords: 688 retina •
762 vitreoretinal surgery •
763 vitreous