What Are the Types of Glaucoma?

Classification by Age:

• Congenital (Age 0)

• Infantile (Ages 0-2)

• Juvenile (Ages 2-34)

• Adult (Ages 35+)

Classification by Glaucoma Types and Mechanism:

• Open-angle

• Closed-angle

• Mixed type

Glaucoma can primarily be seen in two types: open-angle and closed-angle glaucoma.

Open-Angle Glaucoma

It is the most common type. 85-90% of glaucomas are of this type. This is a chronic disease. In open-angle glaucoma, an abnormality in the trabecular meshwork, which is the drainage site of the intraocular fluid, creates resistance. In this case, the aqueous humor begins to have difficulty leaving the eye, and thus the pressure inside the eye slowly begins to increase. This slow rise causes no symptoms, and the diagnosis can be delayed until there is an advanced degree of loss. In patients with open-angle glaucoma, the disease continues its insidious course without giving any obvious symptoms, and the patient is unaware of their disease. Loss of vision can only be found by performing some advanced tests.

The patient only realizes that their vision has deteriorated and decreased as they approach the final stage and consults a doctor. However, in a patient in this situation, the optic nerve has been largely destroyed, and the visual field has narrowed significantly. The treatment to be applied only helps to preserve the existing vision. Lost vision cannot be reversed. This increased pressure begins to destroy the nerve fibers of the retina through a mechanical effect. Nerve fiber destruction is best followed by visual field examinations. When these destructions reach a certain level, they cause cupping in the optic nerve head. The amount of cupping is directly proportional to the damage. Untreated, uncontrolled glaucoma causes the entire optic nerve head to collapse, terminating vision.

This group of Glaucoma has High-Pressure, Normal-Pressure, and secondary types.

Its most common type is the one with high intraocular pressure. It is seen at a rate of approximately 1/100, and more than half of the patients are unaware of their condition. If left untreated, it has a blinding characteristic insidiously over the years.

a-) Normal-Tension Open-Angle Glaucoma Also known as low-tension glaucoma. Despite normal IOP (Intraocular Pressure), there is visual field loss and optic nerve damage. In normal-tension open-angle glaucoma, unlike all other glaucomas, the intraocular pressure is within the limits considered the universal normal value; the intraocular pressure does not exceed 22 mmHg. The sensitization and weakening of the optic nerve head of these eyes due to circulatory insufficiency cause them to be unable to withstand even intraocular pressures considered normal. While the intraocular pressure is normal, the optic nerve head cups, and visual field defects occur. Vasospastic conditions such as migraines and Raynaud’s phenomenon (those whose fingers get very cold and turn purple in the cold), and people whose blood pressure drops significantly at night due to using antihypertensive treatment carry a risk factor for normal-tension glaucoma. It is especially common in old age. Since there is a circulatory disorder in the optic nerve in these people, the IOP needs to be reduced even below normal values.

b-) Ocular Hypertension It is like the opposite of normal-tension open-angle glaucoma. Although IOP is high, visual field loss and optic nerve damage are not seen. If the intraocular pressure is 22 mmHg and above and no glaucoma damage is detected in the optic nerve fibers, this condition is not considered glaucoma. In this condition, called ocular hypertension, treatment is not required. However, follow-up is necessary as it may turn into glaucoma in the future. As long as the intraocular pressure remains high, visual field examinations are performed at appropriate intervals. As long as the optic nerve fibers are documented to be healthy, the patient is followed up without treatment.

c-) Congenital and Infantile Glaucomas Seen rarely at a rate of 1/10,000, this condition is observed at birth. In babies, the drainage angle develops congenitally defective. It is present from birth. Within a few months, it manifests itself with significant enlargement of the eye, closing the eye in the light, watering, and clouding. When the intraocular pressure rises in babies with glaucoma, the cornea loses its transparency and becomes cloudy, and the eye begins to tear. These are the findings that first attract the attention of the parents. If the intraocular pressure has increased before the age of 3 and this situation is not noticed, the eye begins to enlarge (ox eye appearance). If this condition is unilateral, it is easily recognized; if it is bilateral, the diagnosis may be delayed. The treatment in these types of glaucoma is almost always surgical. If early surgical treatment is not performed, it ends in permanent blindness for life. Due to congenital structural problems, there may be a need for repeated surgeries and very close follow-ups.

Closed-Angle Glaucoma

Angle-Closure Glaucoma (Glaucoma Crisis) It makes up about 5-10% of patients with glaucoma. It is mostly observed in people with a narrow drainage angle or an eye structure prone to closure. Trabecular drainage is normal. It can be hereditary and can be seen simultaneously in different members of the same family. It is more common in hyperopes (farsighted people). A glaucoma crisis is observed at an average age of 60, 4 times more often in women, and more in those with a family history due to its anatomical feature.

In addition, diabetes, retinal vascular occlusions, uveitis, complicated cataract surgeries, and various conditions cause angle-closure glaucoma secondarily. Sometimes open-angle glaucoma and angle-closure glaucoma progress together. The anterior chamber in these people is narrower than in normal people. As they age, this angle narrows even more due to the enlargement of the lens, and IOP rises. When the angle is completely closed, acute glaucoma occurs. The pupil dilating and the iris covering and blocking the drainage angle causes the aqueous fluid to be trapped inside the eye. This type of glaucoma presents with a very noisy picture, exactly the opposite of the silent, asymptomatic, insidious glaucoma type (Open-Angle Glaucoma) described above, which constitutes the majority. Most attacks occur in the dark or in stressful situations. Because in these situations, the pupil dilates and the angle narrows.

Furthermore, antidepressants, cold medications, antihistamines, and nausea medications that dilate the pupil can also create a glaucoma crisis in the eye. Mild attacks can subside on their own by moving to a bright environment or sleeping. Because in these cases, the pupil constricts. In this picture, called angle-closure glaucoma or acute glaucoma crisis, symptoms of sudden severe pain in the eye, redness, blurred and decreased vision, sensitivity to light, nausea, and vomiting appear. The eye pressure of a patient presenting to the doctor with this picture is usually found at very high levels such as 40-50 mmHg or higher. Intraocular pressure at these levels paralyzes the pupil.

The eye pain is severe enough to cause vomiting. This is an emergency. If treatment is delayed, it leads to vision loss. Cataracts and optic nerve damage can develop rapidly. This high eye pressure must be urgently lowered with medication, and the patient must be taken for laser treatment and, if necessary, surgery to resolve the problem. Otherwise, if the patient delays consulting a doctor, complete vision loss occurs within a few days with this high eye pressure. The patient experiencing these symptoms must consult a doctor as soon as possible without trying to reduce the pain with painkillers.

People with a narrow drainage angle are generally warned by their doctors about such a crisis. If eye pain is accompanied by a hardening of the eye, a doctor should be consulted immediately.