Abstract
Purpose: :
To explore relationships between functional parameters obtained from multifocal electroretinogram (mfERG) and Humphrey Field Analyzer (HFA), and structural parameters by Heidelberg Retina Tomograph (HRTII) in glaucoma patients.
Methods: :
MfERGs of 25 normal volunteers and 30 open-angle glaucoma patients were recorded. The glaucoma patients also were evaluated with HFA, and HRTII. All tests were performed within 6 months of each other. In glaucoma patients, they were assigned into three subgroups based on a level of mean deviation (MD) obtained from HFA using the central 30-2 program (i.e. Group 1: -5 dB < MD, Group 2: -10 dB < MD < -5 dB, Group 3: MD < -10 dB). The relationships among the parameters obtained from mfERG, HRTII parameters, and visual field indexes were analyzed by coefficients and linear regression analysis.
Results: :
The amplitude ratio in the nasal to temporal hemisphere of the second order kernel response within the central 5° (N/T ratio) was 0.64 ± 0.14, 0.80 ± 0.16, 0.83 ± 0.15, and 0.96±0.14 in the normals, Group 1, Group 2, and Group 3, respectively. There was a statistically significant difference among the 4 groups (P < 0.0001; ANOVA). Additionally, the mfERG parameter showed significant correlations with MD (r2=0.209, P= 0.0248) and pattern standard deviation (r2=0.25, P= 0.0051). However, any global and sectoral HRT II parameters failed to correlate with N/T ratio.
Conclusions: :
Decrease in the nasal-temporal asymmetry in amplitude of the second order kernel responses within the central 5° might reflect functional damage more than morphological change in glaucoma.
Keywords: clinical research methodology • electroretinography: clinical • imaging/image analysis: clinical