Imagine the surface of a white, shiny, perfectly smooth wall on which images are projected. Every detail appears sharp. Now imagine that inside this wall a pipe breaks and a water leak occurs: the plaster rises and the images distort. Action must be taken as soon as possible, before the patch of water expands and the wall is damaged.
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“Something very similar can happen in the eye,” he says Giovanni StaurenghiProfessor of Diseases of the Visual Apparatus at the State University of Milan, Sacco Hospital: “The retina is like a wall behind which new defective blood vessels can form, causing continuous leaks and ‘wet spots’, which compromise the sight”.
This condition has a name: neovascular or, precisely, wet macular degeneration. There is also another form of macular degeneration, called dry or atrophic, in which it is as if the plaster of the wall crumbles and holes are formed in which it is no longer possible to project images. Little is said about it, but it is a frequent disease: it is estimated that the two forms, together, affect over a million people in Italy and that they represent the most common cause of blindness and low vision after the age of 55.
What happens to the eyes
The part of the retina affected is the central one, called the macula, to which we owe the “detailed” vision thanks to which, for example, we can read. Peripheral vision, on the other hand, remains unaffected. But what happens in the eye? “At the beginning – replies Staurenghi – roundish deposits are formed on the bottom of the eye, called drusen. In this phase, the visual acuity does not decrease, but it may be more difficult to see in the dark or you are more easily dazzled by the light “.
It is the advanced form – dry or wet – which however puts the eyesight at risk: “Dry macular degeneration progresses very slowly, while in the wet form the time factor plays a very important role and it is good to go to the ophthalmologist or to the ready as soon as possible rescue, within a maximum of two days from when it is noticed that the details, for example the jamb of a door, observed with one eye at a time appear deformed “.
While there is currently no cure for the dry form, there have been several innovations for the wet form in recent years, and some important ones are on the way. The history of this disease has been changed by targeted therapies capable of “targeting” Vegf-A (vascular endothelial growth factor-A), a protein that promotes the growth of blood vessels under the retina and increases its permeability. By inhibiting Vegf-A it is possible to stop the loss of liquid and recover a few tenths of sight.
The drugs used are monoclonal antibodies – ranibizumab or brolucizumab – or synthetic proteins – such as aflibercept – which are administered directly into the eye via intravitreal injections, and which have now become the standard of care.
One of the novelties expected for next year concerns a new monoclonal antibody just approved in the US, faricimab. It is an antibody called bispecific because it has two targets: Vegf-A and angiopoietin-2 (Ang-2), another protein which, if present in excess, alters the development of blood vessels and makes them more inflamed and fragile. In clinical studies recently published on Lancetthis drug has been shown to be as effective as current drugs in vision recovery, with the advantage that it can be administered at longer intervals (every 3-4 months instead of every 1-2).
One of the objectives of the research is in fact to lengthen the times between injections as much as possible. The reasons are easy to understand. The first is access to treatment: patients are elderly, perhaps they live far from hospitals or cannot go there alone. The second concerns the ability of hospitals to respond to the great demand and ensure continuity of care: “Today – underlines, in fact, the expert – we know that the approach that gives the best results is the proactive one, in which the patient is treated. before the liquid is formed again. In which, that is, we are able to prevent the acute phases “.
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That’s why another promising avenue is that of “slow-release” micro-devices: eye implants filled with one of the drugs, ranibizumab. It is a maintenance therapy that has the advantage of requiring a new refill every 6 months (24 weeks) and releasing the drug constantly, without peaks.
“This path could prove to be the most effective for maintaining visual acuity in the long term. It is essential – concludes Staurenghi – that at the regional health level the choice of therapy is not based only on the price of drugs, but also considers the cost of the entire path of a patient, including the loss of working days of carers due to the increased number of visits, as well as the advantage of freeing up space and staff to treat new patients “.
He tests
There is an exercise that helps to understand if there is a problem with the macula and that can also be done on your own: the Amsler test. The image is used of a square of about 10 centimeters on each side, divided into smaller squares (to form a grid) and with a black dot in the center. You have to stare at the ball from a distance of about 30 centimeters, first with one eye and then with the other (wearing your own eyeglasses if you use them normally): if the squares appear to have irregular shapes or different sizes, the lines appear crooked or more or less dark spots appear, it is necessary to visit your ophthalmologist as soon as possible, or to go to the emergency room if the alterations persist after two days.