Retinal venous pressure in the non-affected eye of patients with retinal vein occlusions

Background: To measure the retinal venous pressure (RVP) in both eyes of patients with unilateral central retinal vein occlusions and to compare these values to controls. Methods: The study included 31 patients with unilateral central retinal vein occlusions (CRVO) and 31 controls who were matched by age, sex, and systemic disease. RVP was measured in all patients bilaterally by means of contact lens ophthalmodynamometry, and the RVP measurements of the affected and unaffected eyes of patients were compared to the RVPs of controls. Ophthalmodynamometry is done by applying an increasing pressure on the eye via a contact lens. The minimum force required to induce a venous pulsation is called ophthalmodynamometric force (ODF). The RVP is defined and calculated as the sum of ODF and intraocular pressure (IOP) [RVP = ODF + IOP]. Results: The RVP group means ± SD were as follows: patient's affected eyes (45.0 ± 11.6mmHg), patient's unaffected eyes (38.0 ± 11.1mmHg) ,and (17.7 ± 6.7mmHg) in the eyes of controls. The values of RVP, even in the patients unaffected eyes, were significantly higher than in the eyes of controls (P <0.001). Conclusions: In patients with CRVO, the RVP is increased in both the affected as well as in the unaffected contralateral eye