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References: Sriram P, Graham SL, Wang C, et al. Transsynaptic retinal degeneration in optic neuropathies: optical coherence tomography study. Invest Ophthalmol Vis Sci 2012;53:1271–5.Gills JP Jr, Wadsworth JA. Degeneration of the inner nuclear layer of the retina following lesions of the optic nerve. Trans Am Ophthalmol Soc 1966;64:66–88.Kessel L, Hamann S,
Clinical Takeaways: The detection of MME has important prognostic and therapeutic implicationsThe presence of microcysts has been associated with a poor long-term functional outcome in patients with MS and ARMD compared to those without MMEMicrocystic changes are most frequently observed in ARMD, post-op after vitrectomy and CE, and in ERMsThe percentage
Back to the Case: Why did the patient present with worsening symptoms? All patients have a decrease in ganglion cells as they age; however, there is enough of a reserve that it does not significantly affect visual function in healthy patients Normal loss is ~0.6% per year If you suffer
Follows midget cell distribution: The microcysts cause a diffraction of the infrared reflex originating from layers below the edema, thereby leading to a dark appearance of the MME in infrared images
Support of a Retrograde Process: Prolonged time course to onset of MMEMME 6.5-6.8 years following diagnosis of optic neuropathyMME respects topographic distribution of RNFLReduced thickness of NFL and ganglion cell layer in areas affected by MME
Pathophysiology: Retrograde trans-synpatic degeneration from optic neuropathy causes degeneration of the INL with formation of cystic spaces Muller cells transverse through the entire retina with the bulk of their cell body in the INL Muller cells maintain homeostasis of the retina, support neuronal activity, and regulate the blood retinal barrier
Review of Anatomy: Microcysts form in the inner nuclear layerMuller cells are the most common glial cell in the retinaMME likely secondary to Muller cell dysfunction
Diagnosis: Microcystic Macular Edema MME has also been described in compressive optic neuropathy, Leber’s heredity optic neuropathy, and dominant optic atrophy MME not dependent on site of optic nerve damage Not restricted to neurologic etiologies- has been described in ARMD, idiopathic juxtafoveal retinal telangiectasis, and tamoxifen retinopathy Muller cell dysfunction
Diagnosis: Microcystic Macular Edema Microcysts present in the inner nuclear layer (INL)Can be a sign of optic neuropathy (glaucoma, autosomal dominant optic atrophy, LHON, NMO, compression)Caused by retrograde degeneration of intraretinal layers which results in impaired fluid resorption in the maculaOften described in patients with multiple sclerosis, but can be found
