Age-Related Macular Degeneration: What to look for - could it be treated?

The leading cause of blindness in developed countries for people of the age of 50 and above is Age-Related Macular Degeneration (ARMD), (Care to guess what the leading cause is in developing countries?). Although the exact cause is still unknown, it is mostly thought to be vascular.

 

Risk factors: include increasing age, smoking, family history and light-coloured eyes.

 

Types: dry ARMD and "wet" or exudative ARMD

 

Clinical Findings: drusen and RPE changes are often the findings of the first stages, then eventually the macular atrophy becomes more distinct - in the event that the disease progresses. Could it stop at this point with minimal visual loss? The answer is YES :D

EARLY ARMD

Slow vision loss over the years occurs from the gradual increasing and growing of the macular atrophy. Usually the macular atrophy is symmetric between both eyes, but the VA could differ between them; especially at the initial phase.

DRY ARMD

Wet ARMD includes an additional finding, which is choroidal neavascularization (CNV); it is thus believed that the diseased retina stimulates the formation of these smaller blood vessels due to the decreased amounts of nutrition and slow transport of wastes. CNV, notice the RPE detachment.

 After a while, these weak blood vessels can leak fluids or blood under the layer of the retina, causing it to be an uneven surface (leading to metamophopsia). 

CNV, bleeding At this stage, the VA could range between 20/20 to 20/50, depending on the presence of retinal atrophy and the CNV location. The vision loss can also be an acute reaction that is secondary to the CNV blood leakage; in this case, there would be a significant drop in the patient's VA (could even reach counting fingers) in a matter of minutes! The areas of CNV eventually lead to the death of the retina above it (يبي يكحلها عماها). 

 The final stage of ARMD is the scarring where highly significant vision loss is present. 

  Wet ARMD, scarring

 

How do we differentiate between dry and wet ARMD? Fluorescein Angiography (FA):

In dry ARMD, you will see: Drusen fluorescience, and defects of the RPE.

In wet ARMD, you will see: dye leakage in areas of CNV which could be diffuse (ocult CNV), or with localized (classic CNV).

 FA of ARMD, classic CNV

Optical Coherance Tomography (OCT) also shows RPE detachment if present.  an example of how an RPE detachment would look in an OCT image

 

Treatment:

In dry ARMD: PreserVision vitaminsThere is so far no specicific treatment to reverse vision loss. Patients are advised:

 

> to take the AREDS (age-related eye disease study) vitamin formula.

> to stop smoking

> to use an Amsler grid in order to monitor the appearance of CNV. 

 Amsler grid, a first indication of CNV

In wet ARMD: destroying the CNV before blood leakage occurs. This is usually done by laser photocoagulation, however, this usually leaves large scotomas.

 Scarring after laser treatment 

Therefore, newer treatments are developing such as photodynamic therapy, and intravitreal injection of VEGF inhibitors. (which will be spoken of later on). 

 Intravitreal injection of VEGF inhibitors