Glaucoma is an eye condition characterised by damage to the eye nerve, which can result in vision loss and blindness. Glaucoma is also known as the “The Silent Thief of Sight”, as early glaucoma has no symptoms and by the time the patient notices any visual impairment, it is too late as the glaucoma is already advanced.
Another eye condition that can result in vision loss and blindness is cataract. As both glaucoma and cataract can result in vision loss, patients often mistake one condition for the other.
Glaucoma and cataract are two completely different diseases, with different treatment strategies. In this article, please allow me to address some common questions frequently posed by patients, including;
• The differences between cataract and glaucoma
• Whether surgery should be performed immediately after diagnosing glaucoma
• The newest treatment for glaucoma
| Cataract | Glaucoma |
| Caused by a cloudy lens in your eye | Caused by damage to the eye nerve, usually because the eye pressure is too high. If untreated, this leads to loss of vision and blindness |
| Vision loss associated with cataract is reversible after cataract surgery | Vision loss associated with glaucoma is permanent and irreversible even after surgery is performed |
| Affects the lens of the eye | Affects the eye nerve |
| Symptoms include cloudy and blurry vision, glare, and faded colours | Few or no symptoms in the early stages |
| Cataract surgery can be considered when the cataract affects your quality of life; surgery is usually not urgent because the vision loss due to a cataract is often reversible | Early diagnosis and treatment are important to prevent further permanent vision loss |
| Usually progresses slowly over years | Variable; damage to the eye nerve caused by glaucoma is usually slowly progressive but if the eye pressure is very high, the progression can be rapid |
| Treatment involves replacing the cloudy lens with an intraocular lens | Treatment involves either increasing the drainage of fluid from the eye or reducing fluid production within the eye, to lower the eye pressure |
Both cataract and glaucoma can only be detected through regular detailed eye examinations.
Although glaucoma cannot be cured, there are various treatment options available to help prevent further vision loss and blindness. These treatment options are:
There are two types of medications for glaucoma: eye drops and oral medications. Eye drops are often the first line of treatment for glaucoma. Oral glaucoma medications are associated with significant systemic side effects (including kidney stones and metabolic acidosis), hence should be used short-term with close monitoring of kidney function, and are not appropriate for long-term consumption.
Glaucoma medications work by reducing the intraocular pressure within the eye by either lowering the production of fluid in your eye or by improving fluid drainage out of your eye.
Glaucoma eye drops that lower the production of fluid in your eye include:
Glaucoma eye drops that improve fluid drainage out of your eye include:
There are various side effects associated with topical glaucoma medications, including allergies, blurred vision, eye redness, and eye discomfort. You must be extremely compliant with your eye drop regime in order to prevent your glaucoma from progressing.
Glaucoma surgery is an option if:
Types of glaucoma surgery in Singapore include:
Lifelong follow-up and monitoring are required to ensure that your glaucoma is not progressing.
It is important to note that glaucoma treatment is individualised, according to the severity of the glaucoma, the number of eye drops required to control eye pressure, age of the patient, and the patient’s preference.
Choosing the best glaucoma treatment for each patient involves weighing the risk of treatment and the risk of vision loss from glaucoma.
Hence, the first line of treatment is usually glaucoma medications. If eye drops are able to control the patient’s eye pressure with minimal side effects, then the use of eye drops is continued as long as the glaucoma remains under control.
If the patient has both cataract and glaucoma, they could choose to undergo either cataract surgery alone, or combined cataract surgery with glaucoma surgery to reduce or eliminate the need for glaucoma eye drops. Numerous studies have shown that the risk of complications from combined cataract surgery and MIGS is similar to that from cataract surgery alone, while the eye pressure control from MIGS is lower.
Patients with mild to moderate glaucoma are at low risk of vision loss from glaucoma, and these patients are good candidates for MIGS which has a high safety profile. With careful patient selection, MIGS can potentially free this group of patients from glaucoma eye drops after the procedure [1].
Patients with advanced glaucoma may undergo conventional glaucoma surgery such as trabeculectomy and tube implant surgery as these are more effective at lowering intraocular pressure but are also associated with more potential complications.
MIGS is one of the newest treatment options for glaucoma. It uses microscopic devices and small incisions to lower the eye pressure and is considered a safer option compared to conventional glaucoma surgery. It also has a faster recovery time.
Different MIGS devices work in different ways, and they reduce eye pressure by either:
All three mechanisms result in the reduction of eye pressure. This preserves the function of the eye nerve, thereby minimising vision loss and preventing blindness.
There is no cure for glaucoma but if detected and treated early, further vision loss and blindness can be prevented. If you are in the high-risk group (e.g., aged over 55, family history of glaucoma, medical conditions such as high blood pressure and diabetes), you must have regular eye examinations to screen for glaucoma, the “silent thief of sight”. Ideally, regular eye examinations should start from the age of 40 years.
If you have any questions regarding glaucoma treatment, please feel free to drop me a message.
References
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