On this page we have included a list of the various visual disorders. Take note of the differences that exist in comparison to normal vision.
MYOPIA (nearsightedness) is an ocular disorder that is characterized by blurred vision when looking at distant objects. The eye acquires a greater than normal ocular length, in turn affecting the location of focus in the retina. The focus is made at a point situated in front of the retina causing images to appear blurred. Persons with myopia see objects up close very well, but objects at a distance very poorly. The more severe the myopia becomes, the greater the need to bring things near to see them well. In the majority of cases, the causes of severe myopia are genetically predetermined, not caused by the behavior of the person. On the other hand, because of today’s increasing academic demands, myopia that begins in childhood is without a doubt due to the adaptation of the visual system for looking at objects up close.
HYPEROPIA (farsightedness) tends to be defined as the opposite of myopia. This disorder is characterized by blurred vision when looking at near objects and normal vision when looking at objects at a distance. The hyperopic eye focuses the images behind the retina; this can be caused by a lower than normal ocular length. As with myopia, the most common cause of farsightedness is genetics. Hyperopia causes blurred vision when looking at objects up close and headaches that increase throughout the day, especially if the person’s work requires looking at objects at a short distance.
ASTIGMATISM is a condition characterized by distorted vision due to a non-spherical cornea that therefore has different curvatures in the various planes. The ability to focus on images in the retina is determined by the direction and the distance of the person from the object they are looking at. The eye is consequently not capable of focusing correctly either on far or near objects. The condition can provoke headaches and even incorrect posture of the head.
PRESBYOPIA is a refractive disorder that starts in the 40s and affects most people. The eye muscle’s ability to vary the power of the crystalline lens is progressively lost; this results in a loss of the ability to focus on near objects. The most characteristic sign of presbyopia is the need to hold reading materials at a distance.
The crystalline lens is a natural lens that allows for the varying ability of the eye to be able to focus on close objects. Normally the crystalline lens is transparent, but for various reasons (age, medications, traumas or ocular perforations, illnesses, excessive exposure to sunlight without protection…) it can become opaque. The only solution is surgery.
STRABISMUS is the abnormal alignment of one or both eyes. There are different types of strabismus depending on this misalignment; they can be classified as either horizontal or vertical. They can also be classified as constant or intermittent. Children with constant strabismus in one eye receive images differently between the two eyes and the brain cancels out one of the images. It is important to bring children to an ophthalmologist before six months of age, as strabismus can cause amblyopia (lazy eye). Strabismus can be corrected with glasses or surgery.
Increased pressure within the eye can damage the optic nerve causing the progressive loss of peripheral vision. Normally this change is gradual and painless. There are two types of glaucoma: 1) Chronic Glaucoma: Intraocular pressure remains elevated over a prolonged period of time affecting the optic nerve. Peripheral vision then deteriorates slowly. In advanced stages of the illness the patient can suffer from tunnel vision. 2) Acute Glaucoma: An intense sudden pain appears along with a diminishing of vision. This condition can be accompanied by headaches, nausea and vomiting.
MACULAR DEGENERATION (ARMD)
MACULAR DEGENERATION or age-related degeneration (ARMD) is the principle cause of vision loss in persons in their 50s and older. It is a condition that affects a part of the retina known as the macula. The macula is the center of the visual field and allows us to see objects in detail. Although, the macula is a small part of the eye, damage to the macula severely impairs vision.
This condition can manifest itself in two ways: in dry form and in wet form.
Dry ARMD is the most frequent, affecting 10% of persons older than 60. This condition evolves slowly due to the progressive deterioration of the macula.
Wet ARMD is less frequent, but much more aggressive. In this condition, abnormal blood vessels form at the macular level, originating from hemorrhages and resulting in rapid and progressive loss of central vision. The person will first see a dark spot and in time can result in blindness.
The treatment for wet ARMD consists of eliminating the abnormal blood vessels. For this condition, until now, the vessels had to be burned with a thermal laser. The problem with this type of laser is that it not only burns the abnormal blood vessels, but can also cause vision loss. For this reason, thermal lasers are rarely used.
Today there exists a treatment that allows for the halting of the degenerative process – photodynamic therapy. This therapy consists of the administration of medicine. Once the medicine has reached the abnormal blood vessels, a cold light is put on the eye which actives the medication. The medicine starts selectively working on the abnormal blood vessels, closing them. The advantage of this treatment is that it does not cause any damage to the retina that surrounds the lesion area. Photodynamic therapy, which lasts approximately 20 minutes, is carried out during a routine visit to the office and is absolutely painless.
In wet ARMD, early detection is of the greatest importance. If we consider the loss of vision that originates from an illness as irrecoverable and that the treatment is fundamentally aimed at avoiding its progression, the quicker the treatment can be established, the better the prognosis will be. Therefore it is advisable to visit the ophthalmologist regularly from the age of 50 on, as it is the best way to prevent blindness as a result of ARMD.