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Variation of multifocal electroretinogram with axial length
1Department of Optometry and Radiography, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China. orhenry@polyu.edu.hk
Summary
Longer eyes, often associated with myopia, show reduced multifocal electroretinogram (mfERG) responses across the retina. This weakening of K1 and K2.1 kernels correlates with increased axial length.
Area of Science:
- Ophthalmology
- Retinal Physiology
- Electrophysiology
Background:
- The multifocal electroretinogram (mfERG) is a key diagnostic tool for retinal function.
- Previous research indicates reduced mfERG responses in myopia and with increased axial length.
Purpose of the Study:
- To investigate how first-order (K1) and second-order (K2.1) mfERG responses vary across the retina in relation to axial length.
Main Methods:
- mfERG was recorded in 30 healthy subjects with varying axial lengths (23.72–28.13 mm).
- Responses were analyzed for amplitudes and implicit times of K1 and K2.1 kernels.
- Correlation between retinal response characteristics and axial length was determined.
Main Results:
- Amplitudes of K1 responses (p1) decreased in central and paracentral regions with increasing axial length.
- K1 responses in the central retina showed significant reduction rates.
- K2.1 responses (n1p1, n2p2) were reduced in paracentral regions (rings 2–5) as axial length increased.
- mfERG amplitudes decreased by 6–10% per millimeter of axial elongation.
Conclusions:
- Longer axial lengths, typical in high myopia, are associated with attenuated mfERG responses across the retina.
- Different mfERG kernel responses exhibit distinct attenuation patterns at varying retinal eccentricities.
- These mfERG changes may reflect underlying morphological alterations due to axial elongation.