There are several types of glaucoma, each with distinct characteristics and treatment approaches. Understanding the specific type is essential for effective management.
Open-Angle Glaucoma
The most common form, accounting for about 90% of all cases. The drainage angle remains open, but the trabecular meshwork becomes less efficient over time. Pressure builds gradually, and vision loss happens slowly over years. It typically affects both eyes, though often unevenly. Treatment usually begins with medicated eye drops and may progress to laser therapy or surgery.
Angle-Closure Glaucoma
Occurs when the iris bulges forward and physically blocks the drainage angle. Can develop gradually (chronic) or suddenly (acute). Acute angle-closure is a medical emergency causing sudden severe eye pain, headache, nausea, and blurred vision. Risk factors include farsightedness, small eyes, and East Asian heritage. Treatment typically involves laser iridotomy to create a new drainage pathway.
Normal-Tension Glaucoma
In this form, optic nerve damage occurs even though intraocular pressure remains within the statistically normal range (below 21 mmHg). This suggests that some optic nerves are more vulnerable to pressure damage, or that other factors such as blood flow to the optic nerve play a role. Treatment aims to lower pressure further below the patient's baseline.
Secondary and Congenital Glaucoma
Secondary glaucoma results from other eye conditions, medications (particularly corticosteroids), injuries, or systemic diseases. Pseudoexfoliation glaucoma and pigmentary glaucoma are common subtypes. Congenital glaucoma is present at birth due to abnormal drainage angle development and typically presents in infancy with tearing, light sensitivity, and cloudy corneas.