Open angle vs angle closure glaucoma are the two primary types of glaucoma which cause damage to the optic nerve and lead to permanent vision loss. In open angle disease which is a more gradual process there are few early warning signs. Angle closure disease is characterized by a narrow or closed drainage angle in the eye. With a sudden attack this type brings on very painful eye pain, blurred vision, redness, halos, and nausea and requires immediate ophthalmic care.
What Is the Difference Between Open-Angle and Angle-Closure Glaucoma?
In what is different between open angle and angle closure glaucomas we see the issue is the outflow of the aqueous humor which is the clear fluid in the front of the eye. While both are the main glaucoma types, the speed at which they progress and the symptoms and treatment may be very different. In open angle glaucoma the drainage angle is always open but the outflow of the fluid is poor. In closed angle glaucoma the iris may shift and block this outflow.
Learn more about glaucoma and Vasan Eye Care’s information on closed-angle glaucoma.
| Feature | Open-Angle Glaucoma | Angle-Closure Glaucoma |
| Drainage angle | Open, but drainage is impaired | Narrow or closed |
| Typical onset | Gradual | Gradual, intermittent or sudden |
| Early symptoms | Often absent | May be absent or episodic |
| Vision changes | Gradual peripheral vision loss | Blur, halos or sudden loss during an acute attack |
| Urgency | Requires timely diagnosis and monitoring | Acute angle closure is an emergency |
In a report on health issues in India we found out that at the age of 40 and over 11.2 million Indians had glaucoma which included 6.48 million with primary open angle glaucoma and 2.54 million with primary angle closure glaucoma.
Open-Angle and Angle-Closure Glaucoma Symptoms
Open angle glaucoma symptoms usually do not present in the early stages. As nerve damage from it progresses, open angle glaucoma symptoms which may appear are of a very slow degeneration of side vision or blind spots. At the advanced stage this can cause tunnel vision. As the symptoms of open angle glaucoma develop slowly and without notice regular eye exams are very important for those at high risk.
Angle closure glaucoma symptoms present in varied ways. In chronic cases the issue may be hard to detect, while in acute cases they may experience temporary blur, halos, or discomfort. With acute angle closure glaucoma patients report very severe eye pain, redness of the eye, blurred vision, headaches, nausea and in some cases even vomiting.
Sudden onset of acute glaucoma symptoms is a medical emergency. At Vasan Eye Care we also present info on acute congestive glaucoma which is an ophthalmic emergency.
Who Is at Risk?
Risk factors for open angle vs angle closure glaucoma overlap but are not identical. Increasing age, family history and raised eye pressure can increase glaucoma risk.
Narrow angle glaucoma has a strong relation to eye anatomy. A shallow anterior chamber may put the iris near the drainage structures. This condition can present before damage to the optic nerve, while in some cases affected eyes may progress to angle closure.
Eye colour alone cannot diagnose glaucoma risk. The Vasan guide to brown eyes vs blue eyes explains why iris colour represents only one anatomical characteristic.
| Risk Factor or Finding | Clinical Relevance |
| Increasing age | Risk rises for several glaucoma types |
| Family history | May indicate inherited susceptibility |
| Raised intraocular pressure | Major risk factor, but not the only diagnostic feature |
| Narrow drainage angle | Increases susceptibility to angle closure |
| Steroid use, inflammation or injury | May contribute to secondary glaucoma |
Conditions caused by medicines, trauma or another eye disorder may develop as secondary glaucoma.
How Are the Different Glaucoma Types Diagnosed?
Diagnosis of open and angle closure glaucoma is not based only on eye pressure. An ophthalmologist may look at the optic nerve, check intra ocular pressure, study peripheral vision and perform gonioscopy which is an exam of the drainage angle. Glaucoma eye tests may include tonometry, optic nerve assessment and visual field testing. Gonioscopy which we do in order to see open, narrow and closed angles also plays a role in differentiating between main glaucoma types.
Narrow angle glaucoma may be discovered during this assessment even before symptoms appear.
How Does Treatment Differ?
Treatment of open angle and angle closure glaucoma is aimed at what is left of the optic nerve function by means of eye pressure control. For open angle we may see prescription eye drops, laser trabeculoplasty or surgery. What we choose is based on the degree of disease, what we see in the optic nerve and the rate of progression.
In closed angle glaucoma treatment must address the blocked outflow tract. In acute attacks pressure must be reduced quickly. When a pupillary block plays a role in narrow angle glaucoma an ophthalmologist may recommend YAG PI or YAG laser peripheral iridotomy.
YAG PI performs a small incision in the iris which in turn allows for better flow of aqueous humour. In some patients we may do additional laser procedures, lens surgery or glaucoma surgery based on their anatomy and what we see clinically. The National Eye Institute reports acute angle closure glaucoma to be a medical emergency. Severe eye pain with blurred vision, redness, nausea or halos around lights should thus present to the emergency room immediately.
Eye Care at Vasan Eye Care
Vasan Eye Care does evaluation of various types of glaucoma through clinical exam and appropriate diagnostic tests. Assessment may include tonometry, gonioscopy, optic nerve imaging and visual field analysis which is followed by discussion on a course of monitoring or treatment.
Persistent vision changes shouldn’t be dismissed. In case of sudden pain in your red eyes, poor vision, nausea, or light sensitivity to the emergency eye care department rather than wait on a regular appointment.
Frequently Asked Questions
1. Which is more dangerous: open-angle or angle-closure glaucoma?
Both in which the optic nerve is damaged. With acute angle closure we have the greater immediate emergency as pressure rises very fast. In open angle glaucoma we have a silent progression which is serious as vision may be lost before we even notice.
2. Can narrow angle glaucoma exist without optic nerve damage?
Yes. A narrow drainage angle does not in itself indicate which of glaucoma has developed in the optic nerve. We use gonioscopy, eye pressure measurement, optic nerve evaluation and other tests to determine if what is required is monitoring, YAG PI or further treatment.
3. Are open angle glaucoma symptoms always noticeable?
No. Open angle glaucoma usually does not present symptoms in its early stage. Peripherally your vision may fall out over time and by the case you notice it the disease has progress which is why it is very important for people to have regular exams if they have a family history of the disease, high intraocular pressure or other risk factors.
4. Can closed angle glaucoma develop slowly?
Yes. Closed angle glaucoma also presents as an acute, intermittent or chronic condition. In chronic cases the disease may go unnoticed, but in intermittent episodes patients may see halos, experience blurred vision or report pain. In the case of sudden serious symptoms get in immediately for evaluation.
References
- National Eye Institute — Glaucoma
https://www.nei.nih.gov/eye-health-information/eye-conditions-and-diseases/glaucoma - Glaucoma in India: Estimated Burden of Disease — PubMed
https://pubmed.ncbi.nlm.nih.gov/20711029/