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Age-Related Macular Degeneration (AMD)

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Age-Related Macular Degeneration (AMD)

Posted on Thursday August 27, 2020

Summary of select, peer reviewed published research on age related macular degeneration:

Age-related macular degeneration (AMD) is a common eye disease that is the leading cause of vision loss for people over 50 years of age. There are two versions of AMD, dry and wet.  Usually a person has “Dry” AMD but approximately 10% of people can progress towards the “Wet” version. AMD blurs the sharp, central vision needed for tasks like reading or driving. Patients with early stage AMD usually show normal visual acuity even though structural and functional abnormalities are already developing. Early detection of AMD provides the best opportunity for treatments that might lessen central vision loss, especially as the disease can progress quickly in some patients.

The stages of AMD can be functionally and structurally evaluated using multifocal electroretinogram (mfERG), subfield dark adaptometry (DA) and optical coherence tomography (OCT). ISCEV guidelines list multifocal ERG (mfERG) as an objective test capable of detecting early stage AMD as well as tracking its progression. Studies indicate mfERG is a very good test for detecting functional changes prior to any measurable changes in structure or visual acuity.

Subfield dark adaptometry (DA) is a psychophysical test that can assist in determining diminished functionality within a patient’s central vision. Research has shown that the slowing of dark adaptation is not only a useful indicator of the likelihood of macular degeneration, but is also a means of assessing the efficacy of any treatments for the disease.

While there is no cure for AMD, treatments are available that may slow the disease’s progression and minimize the severity of vision loss. For the small subset of patient’s with Wet AMD, there are injections that may restore some vision lost due to this condition.

 

References

Gerth C, Delahunt PB, Alam S, et al. Cone-Mediated Multifocal Electroretinogram in Age-Related Macular Degeneration: Progression Over a Long-term Follow-up. Arch Ophthalmol. 2006 March;124(3): 345–352.

Gin TJ, Luu CD, Guymer RH. Central Retinal Function as Measured by the Multifocal Electroretinogram and Flicker Perimetry in Early Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci, November 2011, Vol. 52, No. 12.

Gonzalez-Garcıa E, Vilela C, Navea A, et al. Electrophysiological and Clinical Tests in Dry Age-Related Macular Degeneration Follow-up: Differences Between mfERG and OC. Doc Ophthalmol

Karanjia R, Eng KT, Gale J, et al. Electrophysiological Effects of Intravitreal Avastin (bevacizumab) in the Treatment of Exudative Age-Related Macular Degeneration. Br J Ophthalmol 2008;92:1248–1252.

Lamb TD, Pugh Jr EN. Phototransduction, Dark Adaptation, and Rhodopsin Regeneration-The Proctor Lecture. Invest Ophthalmol Vis Sci. 2006;47(12):5138-5151.

Leibrock CS, Reuter T, Lamb TD. Molecular Basis of Dark Adaptation in Rod Photoreceptors. Eye (1998)12;511-520.

Parravano M, Tedeschi M, Manca D, et al. Effects of Macuprev Supplementation in Age-Related Macular Degeneration: A Double-Blind Randomized Morpho-Functional Study Along 6 Months of Follow- Up. Adv Ther (2019) 36:2493–2505.

Robson AG, Nilsson J, Li S, et al. ISCEV Guide to Visual Electrodiagnostic Procedures. Springer 2018;136:1-26.

Ruseckaite R, Lamb TD, Pianta MJ, Cameron AM. Human Scotopic Dark Adaptation: Comparison of Recoveries of Psychophysical Threshold and ERG b-wave Sensitivity. Journal of Vision (2011) 11(8):2, 1–16.

Rushton WAH. Dark-Adaptation and the Regeneration of Rhodopsin. J. Physiol. (1961), 156;166-178