Multifocal electroretinogram in mild to moderate essential hypertension.

Purpose: To investigate the local retinal dysfunctions in mild to moderate essential hypertensive patients by using multifocal electroretinogram (mfERG).
Methods: Thirty-one patients with stage 1 or stage 2 hypertension (HT) and 31 age- and sex-matched healthy normotensive (NT) subjects were included. Fourteen of the patients had stage 1 and 17 had stage 2 hypertension. Twenty had grade 1 and 11 had grade 2 hypertensive retinopathy. The local retinal functions from the fovea to the peripheral 30 degrees were evaluated by multifocal electroretinogram by dividing this area to central hexagonal area (CH) and four concentric rings around the central hexagon (Rings 1-4). The amplitude and the implicit times of the positive peak (P1) and the negative peak (N1) of the responses were compared between the control subjects and hypertensive patients. Only the right eyes were included. The differences between the hypertensive patients and control subjects were investigated using independent samples t test, and the differences between grade 1 and grade 2 hypertensive retinopathy and stage 1 and stage 2 hypertension were investigated using Mann-Whitney U test.
Results: P1 amplitudes in CH (HT: 129.0 +/- 29.5, NT: 149.1 +/- 45.5, p = 0.043) and in Ring 3 (HT: 37.0 +/- 8.0, NT: 41.7 +/- 7.8, p = 0.024) and N1 amplitude in Ring 1 (HT: 26.8 +/- 7.4, NT: 30.8 +/- 7.8, p = 0.048) in the hypertensive patients was significantly reduced when compared to healthy normotensive subjects. There was no significant difference in terms of P1 and N1 implicit times. There was also no significant difference between the patients with stage 1 or stage 2 hypertension and patients with grade 1 or grade 2 hypertensive retinopathy.
Conclusion: Hypertensive subjects have local retinal dysfunctions with respect to healthy controls. This result probably originated from retinal ischemia due to changes in retinal and/or choroidal circulation in systemic arterial hypertension.