AMD BioMarkers You Should Know About

Going for eye checkups is essential to the future of your vision. However, technologies and diagnosis’s are constantly changing. This has resulted in a continually morphing world of vision research, particularly when it comes to macular degeneration. There have been many instances of discoveries made regarding AMD (age-related macular degeneration) and one exciting sector is the presence of biomarkers. 

Biomarkers are naturally occurring molecules, genes, or characteristics by which a particular pathological or physiological process, disease, or various other conditions can be identified. There are a variety of macular degeneration biomarkers you should know about so you can question your ophthalmologist and especially your optometrist for biomarker scanning. Many times these biomarkers can be missed or ignored which could mean more serious symptoms sneaking up on you in the future. Staying informed and asking for specific biomarker distinctions could be an unexpected sight saver.  

The OCT B Scans

Optical coherence tomography (OCT) is the gold standard for assessing AMD and AMD VEGF (vascular endothelial growth factor) treatment progress. 

Investigative Ophthalmology & Visual Science (IVOS) journal published the study, ‘Optical Coherence Tomography and the Development of Anti-angiogenic [stopping new blood vessel growth] Therapies in Neovascular Age-Related Macular Degeneration’ which concluded,

“Optical coherence tomography imaging was adopted as a VEGF-meter, a method to detect excess VEGF, and evolved to become the gold standard imaging strategy for diagnosing nvAMD [neovascular age-related macular degeneration], assessing treatment responses to anti-VEGF drugs, deciding when to re-treat, and evaluating disease progression.”

The OCT B scan is a diagonal B-scan that can detect various biomarkers to determine how AMD may be developing or how treatment applications may be working. Making sure you are given an OCT B scan is an important request that should probably be ongoing.

Hyper-reflective Dots

Another biomarker that may occur is the presence of hyper-reflective dots. These can be found through OCT scan results as well and may be another concern you discuss with your ophthalmologist and optometrist. 

The Open Ophthalmology Journal reported that,

“The most common causes of HRDs [hyper-reflective dots] excluding DME [diabetic macular edema] and RVO [retinal venous occlusion] seem as active exudative [smelly discharge] AMD. The presence of HRDs in retinal diseases might affect the decisions and the results of the treatment and the prognosis of diseases.”

Hyper-reflective dots may indicate as an imaging biomarker of inflammation. It is well known that AMD is the result of excessive inflammation in and around the retina. By detecting these dots, steroidal medical treatment and alternative remedies such as ARED [age-related eye disease] supplementation can immediately be implemented. 

The Indian Journal of Ophthalmology reported, 

“Based on the evidence (direct and indirect) in the literature, retina specialists world over may be more inclined toward treating patients with HRD on OCT using corticosteroids.”

Hyper-reflective foci

The difference between foci and dots is that foci presents as a curvature. This is found in the biomarker hyper-reflective foci which is another inclination of an inflammatory response which, in this study, is linked to retinitis pigmentosa. Retinitis pigmentosa can be associated with macular degeneration.

According to a study published in Ophthalmology Retina an affiliate of the American Academy of Ophthalmology it was found that, 

“Outer retinal HRF [hyper-reflective foci] number is associated with intraocular inflammation and photoreceptor degeneration in RP [retinitis pigmentosa]. Their distribution in areas with IS/OS [inner and outer segments of photoreceptors] disruption and low autofluorescence suggests that outer retinal HRF reflect defects in the retinal pigment epithelium (RPE) layer caused by RPE cell or microglial migration in response to photoreceptor degeneration.”

The key biomarker location is described in this part of the conclusion: “HRF reflect defects in the retinal pigment epithelium (RPE)” 

Sub-retinal Drusenoid Deposits

It may sound like science fiction but sub-retinal drusenoid deposits (SDD) are a real thing. SDDs are found deep in the lining of the retina and can easily go unnoticed until it is too late. 

A study by researchers from the University of Alabama (UA) published a study in Retina which concluded that,

“Results suggest that SDD in older eyes with normal macular health as defined by the AREDS scale is a risk factor for the development of early AMD. Older adults in seemingly normal macular health yet having SDD may warrant closer clinical monitoring for the possible onset of early AMD.”

In addition to the UA research, SDD was found to directly affect the essential photoreceptor cones of the eye. 

The journal, Investigative Ophthalmology & Visual Science (IOVS) published the study, ‘The Association Between Sub-retinal Drusenoid Deposits in Older Adults in Normal Macular Health and Incident Age-Related Macular Degeneration’ which described the process in its conclusion,

“The fovea is the region with the highest packing density of cones, and cone damage and destruction is an important consequence of late AMD. This is the first study to show that rods may play an important pathophysiologic stimulus for the development of AMD, due to the formation of SDD. A component of early AMD, SDD is a recognized risk factor for the development of both geographic atrophy and choroidal neovascularization.”

As a result of the SDD biomarkers, researchers have been working on using ‘deep learning’ within the OCT scans. These are computer algorithms that could predict and detect these and possibly many other AMD biomarkers. This technology will inevitably become future medicine which is not so far in the future after all. 

“In this study, we sought to develop an effective deep learning method to identify the presence of early AMD biomarkers from OCT images of the retina…We obtained an accuracy of 86% to identify the presence of subretinal drusenoid deposit. Intraretinal hyperreflective foci and hyporeflective foci within drusen were detected with an accuracy of 89% and 88%, respectively…With the growing and critical role of OCT in the understanding and monitoring of AMD progression, the proposed automated system should be of clinical value, not only for increasing diagnostic accuracy and efficiency in clinical practice, but also in the design and execution of future early intervention therapeutic trials.”

Ask your eye doctor to check if you have SDDs.

Plasma Metabolomic Profile 

Detecting biomarkers through a blood test has helped treat and probably save millions of lives across the pathological spectrum. Metabolism is the essential process of life and checking a persons metabolic activity could determine a whole host of clues which may now include a biomarker for AMD.

DocWireNews reported that, 

“Researchers conducted a study to assess and validate plasma metabolomic profiles in patients with AMD and found that patients with AMD have a distinct plasma metabolomic profile compared with patients without AMD, which could signal an easily accessible AMD biomarker.”

The results were presented at the American Society of Retina Specialists 2020 Virtual Annual Meeting in which the researchers reported that, 

“These metabolites could provide insight into disease pathogenesis and be the basis for a precision medicine approach leading to effective therapies for early and intermediate AMD, Metabolomics offers a potential novel tool for early diagnosis and treatment and may point to new targets for the treatment of macular degeneration.”

Find out if you can request a plasma metabolomic profile.

Making sure your ophthalmologist and optometrist are staying vigilant for these clues is something you may want to stay on top of. This is why AMD biomarkers you should know about  are an essential part of patient responsibility.