P 318
Multifocal ERG and PERG in glaucoma patients
T. A. Berninger1, H. Andrielis1,G. Rudolph1, C. Hörmann1, G. B. Arden2
Introduction: It has been reported that the visual fields of glaucoma patients treated with dorzolamed did improve with time. Therefore a follow-up study was designed to prove these observations with objective techniques. Sutter et al. reported that the second order Kernel may represent the function of the inner retina and the optic nerve head. The N95 component of the PERG is known to represent the function of the ganglion cell layer. Therefore we examined glaucoma patients before and about six months after dorzolamed with the M-ERG and PERG.
Methods: M-ERG: 61 hexagons are presented on a 20 inch monochrome monitor driven at a rate of 60 Hz. Six cycles with a duration of 110 sec each were recorded. The luminance of the screen was 180 cd/m2, the contrast nearly 98%. The m-ERG´s were recorded with a contact-lens-electrode (Jet). The m-ERG was evaluated in regard to the amplitude of the 5 rings. PERG: The PERG was recorded with 50 min. of arc checks, presented at 2.2 Hz on a monochrome monitor with 16° diameter and 70 cd/m2. At least 100 responses were averaged and stored. The amplitudes of the P-50 and N-95 components and the ratio P-50/N-95 were evaluated. The PERG was recorded with a gold foil electrode. 15 patients (30 affected eyes) with glaucoma were examined. All patients with media opacities, systemic diseases, refractive errors > +/- 3 D. were excluded. The patients received either dorzolamed alone or in combination with a betablocker. None of the patients included in this study had severe visual field defects.
Results:. An increase of the amplitudes for all 5 rings was seen. The largest increase was observed for the central ring (from 84,0 to 106,2 nV). Also the amplitude of the PERG increased (P-50 from 3,7 µV to 4,0 µV; N-95 from 4,3 µV to 4,8 µV).
Discussion: The amplitudes of both objective tests MF-ERG and PERG increased during the therapy of glaucoma patients with dorzolamed alone or in combination with a betablocker. This result strongly supports the observations that dorzolamed may play a protective role for the visual field of glaucoma patients.
1
Department of Ophthalmology, Ludwig Maximilian University Munich, Mathildenstr. 8, D-80336 Munich; 2City University, Applied Vision Research Centre, 321 Goswell Rd, EC1V7D, London, UK