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[The study of local electroretinogram in age-related macular degeneration]
1Zhongshan Ophthalmic Center, Sun Yat-sen University of Medical Sciences, Guangzhou, China.
Purpose:
Observing the features of electro-activities at macular region in age-related macular degeneration (AMD), and evaluating the sensitivities of local electroretinogram (LERG).
Methods:
The LERG of 2.5, 5, 7.5 degrees at macula had been recorded in 99 eyes (68 dry form, 31 wet form) of 80 AMD patients. The contrast study had also been carried out with visual acuities and lesion areas at the corresponding region.
Results:
The results showed that there were no significant differences between the decreased amplitudes of a and b waves of LERG in dry form AMD with normal controls (P > 0. 05). While significant differences existed in wet form AMD (P < 0.01). The changes of LERG at 2.5 degrees were greater than those of the other two regions. The correlation study on b wave amplitude and visual acuity of AMD patients showed that there was a positive correlation existed between them only in wet form AMD at 2.5 degrees region (r = 0.516, P < 0.05). The negative correlations were observed between amplitudes of b wave and lesion areas in wet form AMD at the three macular regions. Drusen of dry form AMD had no effects on the amplitudes of LERG.
Conclusions:
The impairments on macular function from two types of AMD are different. This study reveals that the LERG is a sensitive method of visual electrophysiology for measuring macular function. The smaller the testing area, the higher the sensitivity.