Photokeratitis: the dark side of the sun

If in last month’s article we tried to expose all the problems in general that a lack of protection against sunlight can cause, this month we want to focus on one of them in particular: photokeratitis.

As we said, the sun’s rays can affect different structures in the eye, from the most external to the most internal. It must be taken into account that in order to see the outside world clearly, it is essential that all these structures that the sunlight passes through are transparent. This causes the light to penetrate to the retina itself, located in the innermost face of the eye. But today we will focus on the effects that the sun’s UV rays have on the first structure, located in the outermost part of the eye: the cornea.

What is the cornea?

The cornea is the ocular structure that is constantly exposed to external agents. It is in direct contact with the air, the water (if we submerge), it is sensitive to cold, heat and of course the sun. That is why it is so important to be especially careful with it.

The cornea is the first of the lenses available to our visual system to be able to focus on objects. It is a fixed lens and the one with the highest power. The other lens, in this mobile case, is the lens. Let’s look at the cornea. Anatomically it is made up of three layers:

  • The corneal epithelium:  It is the outermost layer. It is a very thin layer of just 50 microns thick that covers the cornea like skin. Its main characteristic is that, in the case of suffering an ulceration, it regenerates quite easily. It performs two main functions: protecting the cornea against external elements and nourishing the layer below it, the stroma.
  • The stroma: It is the central layer and the thickest, between 500 and 700 microns. Composed mainly of collagen, it is what gives consistency to the cornea and gives it resistance.
  • The corneal endothelium: This is the innermost layer. It is the thinnest, about 20-30 microns, but with great importance. It is composed of a row of hexagonal cells that are responsible for dehydrating the cornea. A deficit in the number of these cells can have serious visual consequences, causing a significant loss of vision in the patient.

In addition to these three layers, there are other intermediate layers, above and below the stroma, which fulfill other very specific functions. The point is that they all have their importance and must maintain a healthy and stable structure so that we can have a good vision. For this, above all, it is essential that they maintain their transparency. And this is where we see the damage that photokeratitis can cause.

What is photokeratitis?

To quickly summarize it and get a graphic idea of ​​what it is, we can say that it is about burns that appear on the cornea due to prolonged exposure to UV rays from the sun. In the same way that our skin burns if we expose it excessively to the sun without protection, our cornea can also burn if we do not take the appropriate precautions.

What are the effects of UV rays on the eyes?

When UV rays from the sun penetrate through the cornea they can cause ulceration over the stroma. This is the appearance of burned areas in which the transparency of the cornea is lost and, consequently, our vision will be affected.

Depending on the exposure time, the burns will be more or less serious. And if these are repeated frequently, they can have fatal consequences in which corneal transparency is perpetually affected.

Another structure that can suffer an inflammatory process due to excessive sun exposure is the conjunctiva. The conjunctiva is a much more elastic layer than the cornea, also transparent, which covers the sclera, which is the white part of the eye.

What symptoms does photokeratitis cause?

Itching, burning, stinging, constant tearing, sensation of grit inside the eye,… These are just some of the effects that we can notice when photokeratitis appears. It is an inflammatory process that affects the corneal tissue and that obviously alters its structure.

How to treat photokeratitis?

There is no specific treatment for photokeratitis. Just as there is no treatment when we burn our skin on the beach, beyond constantly moisturizing the affected area with cream to speed up its recovery. In the case of the eyes we cannot put any cream. In this case we must resort to the application of drops in the form of artificial tears. Only in the event that the ophthalmologist prescribes it will we take anti-inflammatories or antibiotics, either in the form of eye drops or orally.

Obviously, if the damage caused is much more serious and goes beyond a simple burn, other types of more drastic solutions must be taken. In this case, it will be the ophthalmologist who, after thoroughly reviewing all the affected structures, decides what the treatment should be.

How to prevent photokeratitis?

The answer in this case is obvious: protecting our eyes properly. Good sunglasses, not only in summer but at any time of the year, will be our best allies against the harmful effects of UV rays. Always remember to go to a quality optical center and not buy glasses whose lenses do not have the appropriate filters, since in this case the harmful effects of the sun’s rays can be multiplied.

What to do if you notice any symptoms?

You should always go to an ophthalmologist to make an accurate diagnosis of the pathology and give us the most appropriate treatment. At Clínica Castanera we have the best specialists and the most advanced technology to provide you with the best diagnosis.