Glaucoma Surgery
What is Glaucoma?
Glaucoma is a disease of the optic nerve - the “communication cable” - between your eyes and the brain. Damage to the optic nerve and visual fields is known as glaucoma. The human eye constantly produces and drains a fluid called aqueous humor, maintaining a steady amount of pressure in the eye. When the draining area (called the drainage angle) is blocked or not working properly, the fluid and pressure in the eye builds up, which can progressively damage the optic nerve.
As the nerve becomes increasingly damaged, we develop blind spots in our vision, usually first detected in the outer or ‘peripheral’ visual fields, that are difficult to notice (called peripheral vision damage). These usually go undetected by the patient especially in the early and middle stages of glaucoma damage. They may even be totally undetected until almost the entire nerve is affected, resulting in blindness. This is why glaucoma is often called the “Silent Thief” — because it can steal the vision without the person even knowing there is a problem, until it is too late.
We do have preventative treatments that work in many cases to slow or even sometimes stop the damage from occurring.
But unfortunately, glaucoma damage is irreversible.
At the present time, the damage to the optic nerve cannot be fixed or reversed. Neither, unfortunately, can the damage to the peripheral vision be fixed or reversed yet. Hopefully, however, some day science, medicine, and technology will discover a way to fix glaucoma and reverse the damage.
There are two major types of glaucoma: open-angle glaucoma and closed-angle glaucoma.
Open-Angle Glaucoma
Open-angle glaucoma is the most common type of glaucoma - it affects over 250,000 Canadians a year. It occurs when the eye’s drainage canal becomes slowly clogged over time, gradually increasing pressure in the eye and damaging the optic nerve. Open-angle glaucoma is difficult to detect, as there are no obvious symptoms, but as the condition progresses, blind spots develop in our peripheral vision. Without treatment, it can lead to permanent vision loss.
Closed-Angle Glaucoma
Closed-angle glaucoma (or angle-closure glaucoma) is less common, but can be more urgent. It happens when the drainage angle in the eye is completely blocked. When this happens suddenly and with a large and rapid increase in eye pressure, it causes an acute closed-angle attack. Because acute angle-closure develops quickly and can cause significant damage to the optic nerve, this is a medical emergency requiring immediate treatment to prevent vision loss. Symptoms of an acute angle-closure glaucoma attack: - Vision is suddenly blurry or decreased - Sudden, severe eye or forehead pain - Headache - Nausea or vomiting - Seeing rainbow coloured rings or halos around lights More often though, angle-closure is not acute, but is chronic and painless. In chronic angle-closure glaucoma, there usually are no symptoms, and (like open-angle glaucoma) there is no way for the patient to know there is a problem.
Risk factors for glaucoma include aging, high eye pressure, a family history of glaucoma, African ancestry, significant farsightedness or nearsightedness, past eye trauma, and systemic health problems such as diabetes or migraine headaches. The Canadian Ophthalmology Society recommends that patients at risk of glaucoma and over the age of 60 should have their eyes examined at least once per year.
Diagnosis
Glaucoma is best detected during eye examinations. Often, symptoms can progress undetected until vision is severely impaired. Damage caused by glaucoma cannot be reversed: medical, laser, and surgical solutions exist to prevent further damage.
Treatment Options
Usually, treatment for glaucoma starts with eye drops. Used every day, these eye drops work to lower the pressure in your eye. Some reduce the amount of aqueous fluid made by the eye, others reduce pressure by helping fluid drain more efficiently.
In some cases, using eye drops to treat a patient’s glaucoma is not possible or sufficient to lower the pressure. In these cases, it is time to consider alternative treatments such as laser or surgery. These treatments may be done at our clinic or at the hospital.
Open-Angle Treatment Options
Laser
For patients with open-angle glaucoma, laser treatment can be an effective way to lower eye pressure. A common laser procedure is laser trabeculoplasty, which uses a focused beam of light to open up the clogged drainage canals in the eye, improving the outflow of aqueous humor and reducing pressure. This procedure is typically quick, painless, performed in Dr. Zack’s office, and has a short recovery time. While laser treatment may not completely eliminate the need for medication/eye drops, it can significantly reduce the dosage required or the number of medications needed.
Surgery Options
In cases where laser and medications are insufficient to control eye pressure, glaucoma surgery might be necessary. There are currently many glaucoma surgery options available. It may be surprising to learn that many ophthalmologists agree that the best operation for glaucoma is actually cataract surgery! Although this may not apply to every patient’s case, in some cases cataract surgery can help with glaucoma because many times after cataract surgery eye pressure is lower and the risk of glaucoma — especially acute angle-closure glaucoma in those at risk — is much lower. Traditional glaucoma surgery procedures include trabeculectomy, and large glaucoma shunts. Trabeculectomy is a surgery during which Dr. Zack creates a small flap in the sclera (the white part of the eye) and removes part of the eye’s trabecular meshwork, allowing fluid to drain more freely. Large glaucoma shunts are also referred to as drainage devices. These are implanted to bypass the usual drainage pathway in order to redirect the aqueous humour fluid to a different part of the eye where it can be absorbed. These surgeries are very effective, in some but not all cases, at lowering eye pressure and reducing the amount of medication drops. There are also many newer glaucoma surgery procedures. These include Preserflo shunt, XEN gel stent, GATT goniotomy, KDB goniotomy, and iStents, and others. Some of these are faster to perform than traditional glaucoma surgery, and are still quite effective in some cases. In general, glaucoma surgery is a last resort as it requires a trip to the operating room and has more significant risks and requires a longer recovery period than glaucoma medications and lasers. But glaucoma surgery can be highly effective in lowering eye pressure in the hopes of preventing further damage to the optic nerve and vision.
Closed-Angle Treatment Options
Laser Peripheral Iridotomy (LPI)
For the prevention of acute and chronic angle-closure glaucoma, laser peripheral iridotomy (LPI) is the first line of treatment. To determine if LPI is needed, Dr. Zack will assess your eyes. During the LPI procedure, the laser is used to make a small opening in the iris. Dr. Zack performs this operation in his office. Many people undergo this laser procedure as a preventative measure.
Acute Angle-Closure Emergency
In rare cases, patients will actually experience an attack of acute angle-closure. As discussed above, and repeated here, this is an eye emergency: It happens when the drainage angle in the eye is completely blocked. When this happens suddenly and with a large and rapid increase in eye pressure, it causes an acute closed-angle attack. Because acute angle-closure develops quickly and can cause significant damage to the optic nerve, this is a medical emergency requiring immediate treatment to prevent vision loss. Symptoms of an acute angle-closure attack include sudden blurry or decreased vision, severe eye or forehead pain, headache, nausea or vomiting, and seeing rainbow-colored rings or halos around lights. LPI laser is needed to break the attack. It is performed in the office, and can provide immediate relief, usually along with medication eye drops and sometimes oral medication tablets to lower eye pressure. Sometimes IV medication in the local hospital emergency department is required to break the attack and bring down the pressure before LPI can be performed.
Follow-Up Treatments
Cataract surgery is frequently needed in the days, weeks, months, or years following acute angle-closure attacks. Cataract surgery, during which the extraction of the natural lens of the eye — which with aging has not only become more cloudy but also has grown thicker and larger in size — is performed with implantation of a very thin, clear lens implant. Rarely, glaucoma surgery may be needed for acute angle-closure glaucoma. These interventions can be crucial in preserving vision and preventing severe damage from elevated eye pressure. If you experience any of the symptoms mentioned above, or any other concerning vision or eye problems, get help immediately by contacting Dr. Zack’s office, your optometrist’s office, your family physician’s office, or if necessary by going to your nearest hospital emergency department.