The sun in the eyes. How does it affect?

When spring arrives, the weather is more pleasant, we leave winter behind, the days get longer and longer, we head straight for summer and we can enjoy more hours of sunshine. And like so many other elements, the sun affects our eyes in different ways. Our visual system is a complex compendium of different very precise organs and structures, but also very sensitive. That is why external factors such as the sun, water, wind, etc. They can greatly alter our visual faculties.

Why does the sun affect our eyes?

In the same way that we can notice how the sun burns our skin, if we do not protect ourselves, it can “burn” our eyes

The first thing we have to take into account is that our eyes are made up of different transparent structures:

  • Cornea: it is the outermost lens, the first structure that touches us if they put a finger in our eye.
  • Lens: it is the second lens that we have, it is lentil-shaped and has the ability to modify its shape and size to allow the images to be focused.
  • Vitreous humour: eit is a kind of transparent gelatinous substance that fills our eyeball and gives it the right consistency. It is in direct contact with the retina, which is the structure where all images are reflected.

All these structures are transparent for a reason, and that is so that light can pass through them without losing power and in such a way that we can see clearly. But at the same time it has a disadvantage since in being able to penetrate to the bottom of the eye, sunlight can alter and cause injuries not only to external structures but also to the most internal ones such as the retina.

What diseases can sunlight produce in the eyes?

As we have just said, the fact that light can penetrate to the interior of our eyes can cause alterations in the different structures that will be found along the way.


It is an inflammation of the cornea. Excessive exposure to sunlight on the cornea can cause inflammation of the cornea. Our eyes will begin to sting, we will notice burning or stinging and the visual quality will begin to decline ostensibly. If the exposure is very prolonged, corneal ulcers may even appear, much more painful and complex to treat


The conjunctiva is another transparent structure that covers our eye from the edge of the cornea to the inside of our eyelids. An excess of solar radiation will cause this type of conjunctivitis characterized by the appearance of severe redness accompanied by intense itching, even a sensation of sand in the eyes.


It consists of an excessive and abnormal growth of the conjunctiva above our cornea. Due to the incidence of sunlight, the cells of the conjunctiva begin to grow excessively to protect our eyes. By doing it above our cornea, it can be positioned above our visual axis and therefore even affect our field of vision.


Cataracts appear on the lens. The lens is a very important element to maintain correct vision. It is like a small lentil filled with transparent ice. This ice, over the years, becomes opaque, that is, it becomes denser, more wearable and loses transparency. This causes our vision to become blurred, as if we were seeing through a curtain of water, hence their name: cataracts. Well, the sun’s rays accelerate this process of natural deterioration, which can cause the appearance of premature cataracts, before the age of 55 or 60, which would be the average age at which they usually begin to appear.


As We have already indicated that light is capable of penetrating to the retina itself. One of the smallest and most important structures of our visual system is located on the retina: the macula. It is a small point on which everything on which we focus our gaze is reflected. That is, the macula is our central point of vision, our point of view so to speak, and the rest of our visual field is reflected on the rest of the retina, all the peripheral images.

How to protect our eyes from the sun?

It is clear that the element that we all think about to protect our eyes from the sun are sunglasses. But, it is not the only one that can help us protect our eyes from the sun. A hat or a cap on the hottest days are the perfect complement to sunglasses. The first thing we have to take into account when selecting good sunglasses is that they are certified to protect us against the sun’s UV rays. A guarantee that this is the case is to always buy the glasses in accredited establishments and also make sure that they carry the CE quality mark of the European community.

But in addition to quality, we also have to choose the right filter. There are eyes that are more sensitive than others and therefore will need more powerful filters, that is, ones that better absorb UV rays. You also have to take into account the size. Here the general recommendation is that the bigger the better, in the sense that the bigger they are, the greater the protection zone they will provide. It is better that they cover the entire eye, even on the sides, than that they are very small and allow a lot of light to enter through the periphery. The latter, above all, is very important if we are practicing sports where external elements can penetrate, such as, for example, snow while skiing or simply to prevent the entry of sand from the beach.

Another thing to keep in mind is that the use of sunglasses sun it is recommended that it be throughout the year, not only in the summer months, since the sun’s UV rays also affect the colder months, even on days with clouds and little direct sun.

What to do if I begin to notice a decrease in my visual quality?

At Castanera Ophthalmology Clinic, as a reference center in Barcelona, we always recommend that, in the event of any loss of our visual quality, we quickly go to the ophthalmologist so that he can do an accurate diagnosis and provide us with the best treatment according to the pathology that we may present.

Our expert ophthalmologists always recommend that we check our vision at least once a year, at any age and even if we do not notice any loss of vision. Many ophthalmological diseases and pathologies do not present symptoms until they are already in a situation in which the treatment becomes more complex. That is why our recommendation is always prevention.