Retrobulbar hemodynamics before and after oculopression with and without dorzolamide.

Purpose: To investigate the effect of intraocular pressure (IOP) reduction by oculopression and topical dorzolamide on retrobulbar hemodynamics.

Methods: Sixty patients (70 ± 8.5) solely with cataract diagnosis solely were included in this prospective study. Patients with other systemic and ocular diseases affecting ocular circulation were excluded. On 30 patients (71 ± 8.5), solely oculopression (Honan IOP reducer) was performed. The other half of the patients (69 ± 8.3) additionally received 2 h prior to oculopression additionally topical dorzolamide. Before and after oculopression, IOP was measured and color Doppler imaging (CDI) was performed for the ophthalmic artery (OA), the central retinal artery, and the short posterior ciliary arteries (PCA). Furthermore, blood pressure and heart rate were monitored.

Results: At baseline there was no significant IOP difference between both groups (p = 0.54). IOP, measured prior to oculopression, was significant lower (p < 0.0001) in the group treated with dorzolamide (15.2 mmHg) compared to the other group (17.8 mmHg). Oculopression then led to a significant IOP reduction in all patients (p < 0.0001). There was no significant difference of the delta of IOP reduction between both groups observed (p = 0.47). In either group CDI showed a significant increase of peak systolic velocity (PSV) (p < 0.0001) and end-diastolic velocity (EDV) (p < 0.0001) after oculopression in all vessels. In both groups ocular perfusion pressure increased significantly by 6% (p < 0.0001). After oculopression the PSV of the OA was significantly higher (14%; p < 0.0001) after dorzolamide application than after oculopression alone. Furthermore, in the group with oculopression and dorzolamide treatment EDV of the PCA was significantly higher (21%; p < 0.0001) and resistive index of the PCA was significantly lower (-5.6%; p = 0.001).

Conclusion: IOP reduction by a pure mechanical procedure like oculopression leads to a significant increase of flow velocities of the retrobulbar vessels. This effect can significantly be increased by using dorzolamide prior to oculopression.