November 21, 2020

Prevention in Ophthalmology

How often should I have my eyes examined?

How often our eyes should be examined differs with age and associated diseases. Healthy adults should have at least one eye exam between the ages of 20 and 40, as long as no symptoms are present. Black individuals should have more frequent glaucoma screenings (at least every 4 years). People with diabetes or other diseases that are a risk factor for eye problems should also be examined more frequently (once a year).

In children, the first examination is carried out by paediatricians in the maternity ward, using the red reflex test, which is often reviewed by the family doctor or paediatricians in the various consultations during the first year of life. Currently in Portugal, an ophthalmological screening is carried out in the health centre where the child is registered at 2 and 4 years of age. A new evaluation is advisable before entering primary school to prevent learning difficulties due to ophthalmological disorders.

After the age of 40 the eye examination should be done every two years in healthy people.

About sunglasses

Is the sun bad for your eyes? Should we wear sunglasses? What types of sunglasses should we choose? Are there factors that make our eyes more sensitive to sunlight? These are some of the questions we will try to answer for you!

Several studies have shown that the people most exposed to sunlight have a greater tendency to develop some ocular diseases. Ultraviolet rays (UV) are the sunlight components most involved in the development of these diseases. It is against this solar radiation that we should protect ourselves with sunglasses, so having very dark glasses does not mean more protection for our eyes. We should choose glasses whose lenses filter 99 to 100% of UV light (both UV-A and UV-B).

Rather than the acute action of UV rays on our eyes (which causes skin-like burning on the ocular surface), it is the cumulative effect of long periods of exposure to sunlight that has the most harmful effect on vision. Prolonged exposure to UV light can cause several ocular changes, but the most feared is a change of the macula (see "The Normal Eye") called age-related macular degeneration.

Certain people are more affected by UV radiation, such as those who:

- for professional reasons, are more exposed to the sun,
- live near the beach (where there is greater reflection of sunlight on water and sand),
- live near the equator,
- live in higher altitude areas,
- etc.

Certain medicines can also make eyes more sensitive to light (doxycycline, tetracycline, allopurinol, etc.). Do not forget that a wide-brimmed hat, while not replacing glasses, also plays an important role in sun protection.


Are computer screens bad for our eyes?

To date, and despite several tests carried out in various countries, no scientific evidence has emerged that computer video terminals (screens) are harmful to the eyes.

While it is true that computer screens emit radiation during operation, radiation is produced in very small quantities to be harmful to vision.

Common complaints of eye discomfort, eye fatigue, difficulties in focusing, headaches, etc. are most likely caused by changes in your own eyes or even workplace-related issues. In the first case, you should have a medical examination; your ophthalmologist will assess whether you have eye diseases that could cause such symptoms.

Regarding your workplace, you should consider issues related to occupational medicine and ergonomics to help you solve your problems.

Here is some advice:

- Adjust the brightness and contrast of your monitor so that it is less "harsh" on your eyes.
- Avoid the reflection on the monitor of ambient light or even light from a window. Change the position of your monitor or your desk if necessary.
- Avoid "working in negative", that is, working for example in a text processor with black background and white letters and seeing a text in a white sheet of paper with black letters. Nowadays most programs have a white background with black letters, thus avoiding this inconvenience.
- In certain cases, the use of filters on the computer screen or the use of appropriate glasses may be a good contribution to a less tiring computer work.
- More ergonomic questions can be studied by specialists in occupational medicine or other specialists in this area.


When to take my child to the eye doctor?

A medical eye examination is advisable for all children, even those who apparently have no problems. There are no set dates for the first eye examinations, but in order to detect certain diseases early it is advisable to carry out examinations on the first days of life, around 2 years of age and when starting school. Some ophthalmologists also recommend an examination at 6 months of age.


Some advices

Medicines, if incorrectly handled, can be harmful to your eyes (self-medication is totally inadvisable).

Never use other people's eye drops or ointments (they can transmit diseases and may not be indicated for your case).

Never look directly into the sun (danger of sunburn on the retina).

Never look directly into the welding light (even from a distance) if you do not have appropriate eye protection (danger of corneal burn - ultraviolet keratitis).