One study suggests that OMD arises because of two mutations arising simultaneously, one in RP1L1 and another in ABCA4.OMD is generally believed to be autosomal dominant, meaning that if you get the abnormal gene from only one parent, you can get the disease. However, this does not always seem to be the case.OMD differentiates from Stargardt macular dystrophy in which gene is mutated (RP1L1 instead of ABCA4), the process of OMD isnt a buildup of toxic lipofuscin, and Stargardt is regressive. Physiology
The connection between these mutations and OMD is unclear, but cone density is significantly lower in patients with OMD compared to the general population. Use of adaptive optics to obtain high-resolution retinal images reveal abnormal changes in patients with OMD, including thinning of the foveal thickness and the outer nuclear layer and disruption of the IS/OS line and COST line. Diagnosis
OMD returns negative results for a funduscopic inspection, fluorescein angiogram, and full-field electroretinogram (ERG), for both rod and cone components. The key to diagnosing this disorder is the multifocal ERG (mfERG), providing a single procedure for diagnosis. Onset is known to range from age 6 to 81, with about half of onsets occurring after age 65. Differential diagnosis
A visual field test can differentiate between whether the reduced visual acuity is centered on the optic nerve or the fundus.
Microvenular hemangioma  is an acquired benign vascular tumor that presents as an asymptomatic, slowly growing, 0.5- to 2.0 cm reddish lesion on the forearms or other sites of young to middle-aged adults. See also
List of cutaneous conditions

References


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