Non-exudative age-related macular degeneration

AMD is a slowly progressive condition, and patients at an early stage are usually asymptomatic. However, in some early cases, patients may complain of distorted vision (metamorphopsia), blurred vision, and central and paracentral scotoma. Patients usually complain they have problems with reading where some letters or a whole word is missing. As the disease progresses, the symptoms become more obvious. As the disease progresses, the symptoms become more obvious.

Patients with an exudative type of disease complain of a sudden decrease in vision. Remember – that patients who develop a more advanced stage of a non-exudative form of the disease (centre-involving geographic atrophy) may also complain of “sudden” deterioration in vision.

Patients with AMD have problems with central vision, whilst the peripheral vision remains intact (if there is no other concomitant eye condition like glaucoma). The loss of central visual acuity leads to a reduction in activities of daily living, as well as mobility problems and an increased risk of falls, fractures, and depression in older adults.(9)

It is important to understand that the ageing process in the retina and macula is different from- age-related macular degeneration. Some similar changes make distinguishing normal ageing from pathological changes more difficult. For example, small drusen are often seen as an ageing process, while large and, more importantly, confluent drusen are pathological signs and considered part of the AMD.(10,11)

Drusen

As has already been mentioned, the presence of drusen is the condition’s hallmark. Drusen can be described in – size, colour, morphology, and extent.(12,13) Drusen size is estimated by comparing the shortest diameter of a druse to the width of a significant – retinal vein as it crosses the edge of the optic disc. At this location, the retinal vein has an approximate diameter of 125 µm. Drusen are labelled small when they are less than half the width of the reference vein (<63 µm), medium, or intermediate when judged at least equal to half the vein width but less than the full width (63 µm to <125 µm), and large when they are at least as big as the full retinal vein width (≥125 µm).(14,15)

Drusen may be of white, pale yellow, or yellow colour. Regarding morphology, they are divided into hard and soft drusen. The soft drusen are medium or large-sized and have an amorphous appearance. Their borders are indistinct and may be confluent with one another. Some drusen may be calcified. Drusen may grow and coalesce or regress, resulting in atrophy and depigmentation.(16)

Classical drusen are located below the retinal pigment epithelium (RPE). However, small drusenoid deposits may be located above the RPE and are called subretinal drusenoid deposits or pseudodrusen.(17) Those deposits are also a risk factor for the development of late stages of AMD (geographic atrophy and type 3 CNV in exudative AMD).(18)

The AREDS Group constructed a classification system for – the AREDS studies. It is especially – useful in clinical practice:

• No AMD – Presence of 0 to 5 small-sized drusen (<63 µm).
• Early AMD – Multiple small-sized drusen, – a few moderate-size drusen (63 µm to <125 µm), or pigmentary changes.
• Intermediate AMD – Extensive medium-sized drusen, at least one large drusen (≥125 µm), or extrafoveal geographic atrophy.

• Advanced AMD – Fovea-involving geographic atrophy or signs of exudative age-related macular degeneration (subretinal or sub-RPE haemorrhage, serous fluid, serous PEDs, lipid exudates, fibrovascular scar).

Hyper- and hypo-pigmentary retinal changes

Focal hyperpigmentation areas are more common than hypopigmented areas. They represent clumps of pigment, which may be within RPE or intraretinally. Those changes may be located regardless of the position of the drusen. However, they are more often present at the border of drusen and drusenoid pigment epithelial detachments. Hypopigmented areas have – less pigment, and it has been postulated that hyperpigmentation may precede depigmentation.

Geographic atrophy

It is characterized by a local and sharp demarcation of atrophic outer retinal, RPE, and choriocapillaris layers.(19) Large choroidal vessels are seen at the area of atrophies. It starts in the perifoveal region and progresses towards the fovea. It is bilateral but, in most cases, asymmetrical. Likewise, it may represent a single or multifocal.

Amsler grid – a helpful tool to detect macular changes early. If the practice owns diagnostic imaging modalities like colour fundus photography and/or OCT, try to combine the results of the Amsler grid test and the images to better understand the test’s meaning. Remember, there may be false negative results!

Slit lamp examination – a straightforward approach to recognising the clinical features of the AMD on a slit lamp.

Colour fundus photography – a useful imaging modality to document the macular changes and monitor changes during follow-ups.

Optical coherence tomography – a golden standard imaging modality to recognize the macular changes related to AMD and to distinguish the entities which may look similar . Likewise, it is useful in recognizing drusen from pseudodrusen and – identifying signs of exudative AMD or geographic atrophy early.

There is no current treatment to cure non-exudative age-related macular degeneration. However, the – AREDS studies brought evidence of the benefit of specific supplements, and the studies recommended two formulas.(20,21) Nowadays, AREDS 2 study formula is the one that should be recommended to patients with intermediate and more advanced cases of AMD.

Likewise, avoiding smoking is one of the most important recommendations you can suggest to your patients. Furthermore, increasing green vegetables on the weekly menu and wearing sunglasses are reasonable recommendations supported by some publications.(22,23)

Recent phases II and III trials have evaluated intravitreal C3 and C5 inhibitors and found that they were effective in reducing the growth of the lesion compared to sham injections.(24-26)