Glaucoma is a condition that leads to progressive damage of the optic nerve more often because of raised eye pressure. This nerve damage leads to irreversible vision loss. It is commonly asymptomatic, and the person does not know that they have glaucoma. Glaucoma is diagnosed during routine or regular eye exams. The patient's visual acuity may be normal or reduced. Normal because in glaucoma, the central vision is the last to get affected. What gets involved first is peripheral vision.
The most common form of glaucoma is primary open-angle glaucoma, which occurs when fluid pressure builds up inside the eye because of blockage or narrowing of the drainage channel that carries fluid from the front part of the eye to the back where it drains out. The other less common type is narrow-angle glaucoma or angle-closure glaucoma. The usual eye pressure range is between 10-21 mm of mercury.
When first diagnosed, there are specific tests performed to confirm the diagnosis. These include a field test, pachymetry, and OCT. In addition, eye pressure or IOP ( Intraocular Pressure ) is a must.
Based on the available data, it is estimated that there are approximately 11.2 million persons aged 40 years and older with glaucoma in India. Primary open-angle glaucoma is estimated to affect 6.48 million persons. The estimated number with primary angle-closure glaucoma is 2.54 million. Therefore, those with any form of the primary angle-closure disease could comprise 27.6 million persons. Most people with the disease are undetected, and there exist significant challenges in detecting and treating those with the disease.
When first diagnosed with glaucoma, one may have questions about the best treatment options. All treatment options focus on lowering the eye pressure, but choosing the proper treatment can get challenging when multiple treatment options are presented. Since there is no cure for glaucoma, knowing the pros and cons of various options is crucial.
Both the ophthalmologist and the patient would have to make a choice. Based on their experience, the doctor may find this easy, but evaluating different treatment options can be overwhelming for the patient. The doctor may choose what they think is the best treatment option, and you may decide to go wi h that. Nonetheless, it always helps to know a little more about the right treatment option for you.
The following list of questions will help in this regard, and even though this is not a comprehensive list, it does cover most of the points.
Normal eye pressure is considered between 10-21 mm of mercury ( Hg). If your doctor has diagnosed you with glaucoma, your pressure would likely be higher than 21mm. It is essential to know the eye pressure when first diagnosed with glaucoma because the target eye pressure is calculated based on this pressure reading. You should also know what, according to your doctor, should be your target pressure.
Why should you know this?
You may move locations and may be forced to visit another glaucoma specialist. In that case, when your medical records are not kept up to date, your new doctor has no idea of what the original press re was. As a result, the new doctor will not know if your glaucoma is well controlled or not and should they add more eye drops or perform some laser treatments or some surgical procedure to reduce the pressure further.
You should also know this information for your knowledge. Whenever you come in for a follow-up exam, you should always ask your doctor what the pressure was on that day and compare that to the target pressure. You should be aware of your eye pressure is doing well or not.
There are various types of glaucoma, and the prognosis of each class is different. Primary open-angle glaucoma is the most typical glaucoma and most easily treatable. However, closed-angle glaucomas may need a combination of a few treatment modalities.
Secondary glaucomas caused by uveitis or an eye injury may need other drops to treat the eye condition before actually treating glaucoma.
Why should you know this?
Your doctor will call you for the follow-up visits based on the type of glaucoma you have and your starting eye presure. You will also get an idea of how good or bad your glaucoma is and how important it is that you stick to your follow-up exams in the future.
Treatment options for glaucoma include glaucoma medications, eye drops, laser trabeculoplasty, glaucoma surgery, and minimally invasive glaucoma surgeries (MIGS). Each has pros and cons." Below we discuss common ways to treat glaucoma
Glaucoma eye drops
Over the past many years, the number of anti-glaucoma medications available to treat glaucoma has significantly increased. The efficacy of these drops also has increased. This has resulted in pressure being controlled very well with eye drops alone. Due to this, the number of surgeries for glaucoma patients has dropped the world over. Most likely, this will be the first choice of treatment for your glaucoma. You can consider these drops like blood pressure medications where you have to take them forever without missing a single drop.
Drops are available as single drug bottles or combination drugs. Sometimes your eye doctor may prescribe two or even three eye drops because the pressure is not reaching the target IOP with one slide.
Sometimes even after starting patients on three eye drops, the pressure does not reach the target pressure, and in these situations, you may need additional treatment.
Some patients don't want the trouble of putting eye drops and remembering when to put which drop. These patients opt for an alternative modality of treatment for glaucoma. Others don't want to undergo any procedure, period. And these patients choose eye drops over other procedures.
Yag PI or laser iridotomy
This type of laser is used in closed-angle or narrow-angle glaucoma. As the name suggests, this type of glaucoma has narrow drainage angles. Therefore, this procedure may reduce the elevated pressure to the target IOP or at least lower it a bit so that the number of eye drops needed to bring the pressure to the target IOP reduces.
Patients with narrow or closed-angle glaucoma can present with eye pain and redness along with blurred vision and elevated eye pressure. This type of glaucoma is more commonly seen in patients with a plus refractive error. After the initial treatment with prescription eye drops and tablets, a Yag PI or laser iridotomy glaucoma laser surgery is done to bring down the pressure further. This laser creates a new drainage pathway from the back part to the front part of the eye.
Laser Trabeculoplasty or SLT (Selective laser Trabeculoplasty) is a procedure that will open up the drainage channels of the fluid within the eye (Aqueous Humor). Once the drainage channels open up, the pressure of the eye reduces. It is an OPD procedure meaning its small procedure does not require admission into the h spital. The patient is asked to use certain eye drops post the procedure for a few days, and that's that.
Laser trabeculoplasty is effective, quick, reduces pressure by a few points, and may eliminate the need for the patient to use eye drops. However, the laser is too brief and gentle to damage the eye. Usually, the worst that can happen is that the pressure is not lowered by the amount your glaucoma doctor expected.
One disadvantage is that it may not reduce the elevated pressure to the target IOP and patients may need an additional drop to bring down the pressure. The effectiveness of this procedure also tends to wear off over time. Thus a few years after the procedure, the patient may need to repeat or use additional glaucoma eye drops. This can also cause transient eye problems like pain, discomfort, or a transient rise in pressure like any other procedure.
Yag Laser is also done in individuals at risk of glaucoma because of a family history of glaucoma and narrow drainage angle. A family history of glaucoma is a high risk for glaucoma.
A few surgeries can be performed for the treatment of glaucoma.
Trabeculectomy is the most commonly done procedure. Here an artificial drainage channel is created from the inside of the eye to the outside. The Aqueous Humor then flows out through this opening and reduces the eye pressure. The pressure has to be closely monitored for the first few days after surgery. Sometimes, your glaucoma doctor may adjust the treatment to maintain the pressure post-surgery. These adjustments could include changing the suture used during surgery, suggesting a massage, or giving eye injections. A few months after surgery, the pressure usually stabilizes, and then the frequency of the visits reduces.
Drainage implant surgery
Glaucoma valve implantation is another surgery done for complicated Glaucoma or secondary Glaucoma or when your glaucoma doctor feels that the first surgery won't work. It is also done if a patient has already undergone a trabeculectomy and that surgery failed. Valve surgery is also preferred if significant conjunctival scar tissue is around the eye.
Minimally invasive glaucoma surgery (MIGS)
As mentioned previously, glaucoma surgery is usually performed when the pressure is not controlled with eye drops. However, newer minimally invasive glaucoma surgeries (MIGS for short) are typically combined with cataract surgery to treat mild to moderate open-angle glaucoma. Therefore, for these surgeries to be an option for you, you should have a cataract that impacts your vision and quality of life, and you should have early to moderate open-angle glaucoma. In such a case, one may even consider bypassing medications or lasers in favor of cataract surgery combined with a MIGS procedure. MIGS won't work for advanced glaucomas as one may not achieve the Intraocular target pressure that one desires. On the other hand, these techniques are being tried in congenital glaucoma.
Performing regular cataract surgery reduces eye pressure by a few points. However, in early glaucoma, if there is an associated cataract causing blurry vision, one may consider only doing cataract surgery and seeing what the eye pressures are posted during the surgery.
All treatments have potential side effects, and you must b aware. Based on the side effect, you will decide which is a better treatment option for you.
Some eye drops (like prostaglandin analogs) cause a rise in blood pressure, and some others cause redness, irritation, allergic reactions, and eyelash growth, and thickening. At the same time, some patients may like the later side effect some may not.
Acetazolamide is the commonly used drug to treat glaucoma. There are available as tablets. These can cause mild nausea and also pins and needles in the extremities.
All surgeries have a potential risk of eye infection after surgery. There is also always a risk that the glaucoma surgery may not work and the pressure may not reduce. Patients may need multiple surgeries.
Glaucoma is a condition where your pressures have to be closely monitored.
Pro Tip: There is a condition called Ocular Hypertension. The eye pressure is raised here, but the patient does not have glaucoma. There is also something known as Normal-tension Glaucoma, and here, the eye's anxiety is normal, but the patient still has glaucoma. It is in these conditions that the following investigations become essential.
Your eye doctor will call you for frequent follow-up visits based on your initial pressure and eye condition. You need to know how often you have to come to plan your schedule. Blindness caused by glaucoma is irreversible, and thus you must keep your appointments.
It would help if you also understood that as your pressure stabilizes and the glaucoma doctor is feeling better about your eye pressures, your follow-up visit frequency may reduce. Again, this information would most likely encourage you to follow what your glaucoma doctor has instructed you to do.
Intraocular pressure is the most critical measurement for follow-up of glaucoma. The pressure check is done by something called applanation tonometry. However, apart from IOP measurement, other tests are al o done. Before further investigations, a dilated eye exam is pe formed. The optic nerve and retina are examined. These are the OCT Retinal Nerve fiber layer scan and the fie d test. Field test checks for the peripheral vision of e ch eye. Both these tests check for optic nerve damage. Another test that is sometimes done is the pachymetry to measure the corneal thickness.
People with glaucoma should know how often you need to do these tests in a year and which tests will be needed. In addition, you will get an idea of the amount of time you will spend at the clinic and the cost you will incur at each visit.