Glaucoma

What is Glaucoma?

Glaucoma is a complex group of eye conditions that lead to progressive damage of the optic nerve, the crucial structure that transmits visual information from your eye to your brain. This damage, which is often, but not always, associated with elevated intraocular pressure (IOP), can result in irreversible vision loss and blindness. Glaucoma is often referred to as the "silent thief of sight" because it typically has no noticeable symptoms in its early stages, and vision loss occurs gradually over time without pain or discomfort.

Types of Glaucoma

There are several types of glaucoma, but they are most commonly categorized by the angle of the eye's drainage system.

• Primary Open-Angle Glaucoma

  • This is the most common form of glaucoma. It is a chronic condition where the eye's drainage angle remains open, but the trabecular meshwork (the eye's internal drainage system) doesn't function properly. This leads to a gradual increase in intraocular pressure (IOP), which damages the optic nerve over time.

• Angle-Closure Glaucoma

  • This type of glaucoma occurs when the drainage angle in the eye becomes narrow or blocked, causing a rapid or sudden increase in IOP. This can be a medical emergency and may cause sudden, severe eye pain, headache, blurred vision, and halos around lights.

• Normal-Tension Glaucoma

  • In this type of glaucoma, optic nerve damage and vision loss occur even when the intraocular pressure (IOP) is within the normal range. This is often due to an overly sensitive optic nerve or other factors affecting blood flow to the nerve.

• Secondary Glaucoma

  • Secondary glaucoma is caused by a known eye injury, steroid usage, ocular inflammation, , or pre-existing medical conditions, such as diabetes or tumors, which can lead to increased IOP.

Glaucoma Symptoms

In the early stages, glaucoma typically has no symptoms. The loss of peripheral vision is so gradual that it is often unnoticed until the condition is more advanced. Symptoms, when they do appear, may include:

• A gradual loss of peripheral vision.

• Blurred vision or the appearance of halos around lights.

• Eye pain or headaches (especially in angle-closure glaucoma).

• Nausea and vomiting (in angle-closure glaucoma).

Diagnosis of Glaucoma

Early diagnosis is crucial for managing glaucoma and preserving vision. An ophthalmologist can diagnose the condition during a comprehensive eye examination. The diagnosis typically involves:

• A Dilated Eye Exam: The doctor will use special instruments to view the optic nerve and check for signs of damage, such as a large or asymmetric optic cup.

• Intraocular Pressure (IOP) Measurement: A tonometer is used to measure the pressure inside the eye, which is a key risk factor for glaucoma.

• Optical Coherence Tomography (OCT): An OCT scan provides a detailed cross-sectional image of the optic nerve head and the retinal nerve fiber layer (RNFL), which is crucial for detecting thinning or damage.

• Visual Field Test: This test measures the patient's peripheral vision and can detect any areas of vision loss.

• Gonioscopy: This test allows the doctor to examine the drainage angle of the eye to determine if it is open or closed.

Glaucoma Treatment

The goal of treatment is to lower intraocular pressure (IOP) to a level that prevents further optic nerve damage. While lost vision cannot be restored, treatment can help preserve remaining sight.

• Medical Management

  • Eye Drops: The most common initial treatment. Prescription eye drops either reduce the production of aqueous humor or increase its outflow from the eye.

  • Oral Medications: In some cases, oral medications may be used to help lower IOP.

• Laser Treatments

  • Selective Laser Trabeculoplasty (SLT): A non-invasive laser procedure that improves the eye's natural drainage system, helping to lower IOP.

  • Laser Peripheral Iridotomy (LPI): A laser procedure used for angle-closure glaucoma to create a small opening in the iris, which improves the flow of fluid to the drainage angle.

• Surgical Treatments

  • Micro-Invasive Glaucoma Surgery (MIGS): A group of procedures designed to reduce IOP with a minimally invasive approach. MIGS are often performed in conjunction with cataract surgery.

  • Traditional Filtration Surgery (Trabeculectomy): A surgical procedure that creates a new drainage pathway for aqueous humor, providing a significant and sustained reduction in IOP.

  • Tube-Shunt Surgery: A surgical procedure that involves implanting a small device that acts as a long-term drainage system for the eye.