Multifocal Electroretinogram (mfERG) in a Family with Occult Macular Dystrophy (OMD)

Abstract

A new family with OMD is added to preceeding reports. A reduced visual acuity without visible fundus abnormalities may be misdiagnosed as amblyopia, optic nerve disease or nonorganic visual disorder. The mfERG offers the diagnostic tool to detect a circumscript retinal/macular dysfunction by a single procedure.

A 43-year-old man with reduced visual acuity and normal fundus: occult macular dystrophy—case report

“…These findings strongly suggest that our OMD patient has localized retinal dysfunction in the central visual field. This observation is consistent with published data [1,2,10] describing the patients with this uncommon ocular disease. Most patients with OMD have slight but statistically significant delayed implicit times of P1-wave in the central 60°of the retina [4] indicating early signs of retinal dysfunction not only in the central retina.…”

“…OMD in children is very rare [1,2,5,6]. The best corrected visual acuity (BCVA) ranged from 0.03 (20/600) to 1.2 (20/16), mean equal to 0.2 [2,4,[6][7][8][9][10]. The BCVA below 0.1 is usually observed in patients older than 45 years.…”

Non-Familial Occult Macular Dystrophy

“…Some or all of these cases could be the result of a unique inherited defect which may be either sporadic and/or show variable penetrance and present as a variety of phenotypes [7]. Of course they could also be the result of a recessive pattern of inheritance which might go undetected in immediately preceeding generations.…”

The Clinical Applications of Multifocal Electroretinography: A Systematic Review

“…Because the retinal dysfunction is only localized to the macula, mfERG is very useful in the diagnosis of OMD. 68,112,212,236,269,314,328 The characteristic mfERG abnormalities in OMD include marked reductions in P1 response amplitudes in the central macula and minimal reduction towards the peripheral macula. 236,314 There are also slight but significant delays in P1 implicit times over the entire macular region.…”

“…68,112,212,236,269,314,328 The characteristic mfERG abnormalities in OMD include marked reductions in P1 response amplitudes in the central macula and minimal reduction towards the peripheral macula. 236,314 There are also slight but significant delays in P1 implicit times over the entire macular region. Because patients with OMD do not have visible fundus morphology, mfERG can allow detection of localized foveal cone dysfunction and differentiate OMD from functional visual loss.…”