The most common visual anomalies

 

Refractive errors can be classified in three different groups: myopia, hyperopia and astigmatism.

 

Myopia

Myopia is a visual condition which affects distance vision.

Myopic kids tend to narrow their eyes to see distant objects better, they sit very close to the television, they ask to sit on the front row in class or they take notes from classmates beside them, as they cannot read properly from the board.

Myopia causes can be genetic or environmental, although there is a higher percentage of myopic people because of visual overstrain due to inadequate work conditions or diet disorders.

In order to prevent myopia, it is important to care about environmental conditions as light or nutrition. An adequate treatment includes prescription lenses at reading distance or visual therapies.

 

Hyperopia

Hyperopia is a visual condition which affects vision at reading distance.

Upon birth, we all suffer from hyperopia. However, as we grow, hyperopia diminishes to a normal dioptre value of about 0.5.

People suffering from hyperopia continuously strain vision to focus on close objects. This strain can cause headaches, teariness, itchy eyes, and the loss of focusing capability after a while.

 

Astigmatism

Astigmatism affects vision of both near and distant objects.

It is caused by a deformation of the cornea, which is no longer round and gets more curved from one side than the other, as a rugby ball.

When we are born, we can also suffer from astigmatism, although the level of prescription does not vary as we get older.

There are other types of astigmatism which are not caused by a deformation of the cornea. They are called internal or crystalline astigmatism. This type of astigmatism presents more symptoms than common astigmatism as it varies depending on visual strain.

Astigmatism can be corrected with toric lenses.

 

Presbyopia

Presbyopia consists in the hardening of the crystalline and the loss of elasticity which causes a reduction of the eye focusing capability. Near vision gets worse and blurred.

This condition can be corrected with bifocal and varifocal lenses or with multifocal contact lenses. It can be diagnosed with a complete eye test.

If presbyopia is not corrected, it can cause dizziness, headaches, eye irritation and ocular aches.

 

Glaucoma

Glaucoma is caused by a liquid accumulation on the ocular globe which increases intraocular pressure. It is not painful and it does not present clear symptoms.

It is the second cause of blindness in the world, this is why it is so important to diagnose it in time. In Spain, almost a million people could suffer from glaucoma, but most of them are not aware of it.

Once detected, it is treated with eye drops to diminish the liquid or to help the eye to eliminate it. If these treatments do not work, it also can be treated by laser surgery.

 

Diabetic retinopathy.

It is caused by an alteration of the blood vessels in the retina. It affects diabetic people, regardless of if they are insulin-dependent or not.

It can also cause blindness and it does not present clear symptoms. This is the reason why diabetic people should have an eye test every year.

Macular edemas, or liquid from the retina accumulation, and diabetic retinopathy, or blood drops that difficult vision, can be treated with laser surgery. If the blood is concentrated in the centre of the eye, vitreous humour, an incision is made, after local anaesthesia is applied, to extract the vitreous gel and to replace it with a saline solution. This operation is called vitrectomy.

 

Cataracts

Cataracts are caused by a loss in the crystalline transparency, which becomes similar to a frosted glass.

Cataracts are very common in the elderly. It affects more than 50% of population aged between 65 and 75 years old and more than 70% of population aged more than 75 years old.

If they are not corrected, vision gets progressively worse.

There are different surgery methods. One of the most recent is the ultrasonic phacoemulsification, consisting in a minuscule incision to aspirate the eye’s internal lens and replace it with an intraocular lens. After surgery, cataracts do not occur again although the implanted capsule in the crystalline could become opaque in 50% of patients, requiring a new intervention.

 

In Spain, Social Security pays for cataracts surgery.