Temporal interactive response is resistant to cloudy ocular media in the slow double-stimulation multifocal electroretinogram

• Published in: British journal of ophthalmology Vol. 96; no. 7; pp. 1012 - 1017
• Main Authors: Ho, Wing-Cheung, Chu, Patrick H W, Ng, Yiu-Fai, Tong, Patrick P C, Woo, Victor C P, Chan, Henry H L
• Format: Journal Article
• Language: English
• Published: BMA House, Tavistock Square, London, WC1H 9JR BMJ Publishing Group Ltd 01.07.2012; BMJ Publishing Group; BMJ Publishing Group LTD
• Subjects: Adult; Aged; Biological and medical sciences; Cataract; Cataract - physiopathology; Cataracts; Diabetes; Diabetic retinopathy; double-flash; electrophysiology; Electroretinography; Humans; Laboratories; Light; light scattering; Medical sciences; Middle Aged; Miscellaneous; multifocal electroretinogram; Ophthalmology; Phacoemulsification; Photic Stimulation; psychophysics; Retina; Retina - physiopathology; Scattering, Radiation; Studies; vision; California; Electroretinography; Eye; Resistance; Electrodiagnosis; Ocular; Stimulation; Ophthalmology
• ISSN: 0007-1161; 1468-2079
• DOI: 10.1136/bjophthalmol-2011-301099

AimTo examine the influence of cloudy media on the slow double-stimulation multifocal electroretinogram (mfERG).MethodsSlow double-stimulation mfERG responses were measured from 26 subjects with normal ocular health under normal and light scattering conditions (induced using acrylic sheets) (Experiment 1) and another nine cataract patients before and after cataract surgery (Experiment 2). The amplitudes and implicit times of the first (M1) and second (M2) stimulation were compared under normal and light scattering conditions in Experiment 1 and they were compared under precataract and postcataract surgery in Experiment 2.ResultsCompared with control conditions (normal and postcataract surgery), the M1 amplitude in the central region was significantly reduced in light scattering conditions (acrylic sheets and precataract surgery); the M2 amplitude and both M1 and M2 implicit times of all regions examined were moderately affected in precataract surgery. The M1:M2 amplitude ratio and implicit time ratio were virtually unaffected in cloudy media for either central or mid-peripheral regions.ConclusionCloudy media affects the mfERG amplitude and implicit time in the slow double-stimulation, but does not affect the response ratio (ie, M1:M2 amplitude ratio and implicit time ratio) between the two stimulations. This suggests that the ratio analysis can be applied in patients with mild to moderately cloudy ocular media to evaluate the functional integrity of the retina.