Effect of optical defocus on multifocal ERG responses

Autor: Ho Lung Henry Chan, Andrew W. Siu
Rok vydání: 2003
Předmět:
Zdroj: Clinical and Experimental Optometry. 86:317-322
ISSN: 1444-0938
0816-4622
DOI: 10.1111/j.1444-0938.2003.tb03127.x
Popis: Background: Multifocal electroretinography (mfERG) is a sensitive technique to probe retinal function topographically. Various conditions such as rnacular degeneration decrease the first-order kernel (K1) response magnitude of mfERG. Previous studies have given inconsistent results on the effect of optical defocus due to poor controls. This study investigated the effect of optical defocus on the K1 response of the central retina using a wellcontrolled method. Methods: Twenty subjects were recruited to undergo mfERG measurement using the VERIS 4.0 system. A four millimetre artificial pupil was fitted before each fullydilated right eye, optically corrected for the viewing distance. The implicit times and response amplitudes of nl (first negative trough) and pl (first positive peak) under three different optical defocus conditions (zero dioptres, +1.00 D and +3.00 D) were measured. Results: The implicit times of nl and pl did not demonstrate any significant variation from the central macula to para-macula under different optical defocus conditions. The response amplitude of nl did not show any changes from the central macula to para-macula but the response amplitude of the central macular pl showed a significant reduction by 12 per cent under +1.00 D defocus and +3.00 D defocus. Conclusions: Optical defocus causes mild reduction in mERG at the central macula but there are no significant changes in the periphery. A full optical correction is recommended for mERG measurement to minimise the reduction of the macular response due to optical defocus.
Databáze: OpenAIRE
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