GLAUCOMA

Introduction

Glaucoma is a condition where the eye is affected. The nerve of vision known as the optic nerve is affected in this condition. Vision materializes because of the proper functioning of this nerve. Damage to the optic nerve causes loss of vision first partially and if not treated can cause total blindness. 

One main cause of Glaucoma is because of the increased pressure in the eye known as intraocular pressure. An elevation in the eye pressure leads to damage of the optic nerve. However, sometimes Glaucoma can also occur in presence of normal eye pressure. This could be because of the poor blood flow to the optic nerve. 

Glaucomas are of different types and are mainly categorized as open angle glaucomas and closed angle glaucomas. Open angle glaucomas usually persist for long durations, while the closed angle glaucomas may occur as an acute or chronic condition. The disease can occur in both eyes; however, progression in one eye can differ from the other.

Symptoms & Signs

The signs and symptoms include severe eye pain, red eye, nausea, vomiting, blurred vision and severe headache. Corneal swelling is also seen due to which the patient sees halos around lights. Patients may also experience side vision loss also known as visual field loss.

Classification & Types

Open Angle Glaucoma

Closed Angle Glaucoma

Open angle glaucoma:

• Primary chronic open-angle glaucoma: this is the most common type of glaucoma and its frequency increases with age. The drainage mechanism is clogged and the aqueous fluid cannot drain properly. This increases the pressure in the eyes which causes peripheral vision loss. There is no pain and no symptoms are seen and thus people do not realize the problem until loss of vision does not affect the central visual area.
• Norma Tension Glaucoma: this type of glaucoma occurs due to the decreased blood flow to the optic nerve. It is also known as low tension glaucoma.
• Congenital glaucoma: this condition is rare and an inherited type of glaucoma. In this type the drainage area is not well developed before birth. It causes increased intraocular pressure as well as an enlarged eye.
• Secondary open-angle glaucoma can occur due to eye injury. Secondary glaucoma is caused due to cataract, inflammation of the iris, diabetes and also retinal detachment.
• Pigmentation glaucoma and Exfoliative glaucoma are also commonly seen affecting people.

Angle Closure glaucoma

It is most commonly seen in the Asian countries. This condition may be acute or chronic and the most common thing that occurs here is that the drainage angles of the eye are all anatomically closed and hence the aqueous liquid cannot reach the meshwork resulting in impaired drainage and thus results in glaucoma.

Causes & Risk factors

Glaucoma has no known symptoms and hence it is difficult to diagnose the problem in the early stages. The causes for this condition are mainly attributed to the risk factors. These risk factors mainly include the age, family history of glaucoma, diabetes, history of intraocular pressure, eye injury, use of steroids and conditions like myopia and hyperopia.

Diagnosis

Diagnosis of glaucoma is done by the ophthalmologist by doing a number of tests. All of these tests are non invasive and painless. Tonometry is an important test done; this test measures the firmness of the tone of the surface of the eye and hence helps in determining the intraocular pressure. The more the firmness in the tone, higher is the intraocular pressure. 

Pachymetry is another important test done which is used in the diagnosis and treatment of glaucoma. In this test the thickness of the cornea is measured. Other tests include Ophthalmoscopy and Visual Field Testing.

Treatment Options

Nerve damage is irreversible; however, Glaucoma is a condition which can be controlled by using medication. Medication helps in lowering the elevated intraocular pressure to normal and thus prevents any further nerve damage and visual loss. Medication is mostly in the form of tablets, eye drops and laser surgery.  Eye drops such as Timolol, pilocarpine etc are the most preferred medication in case of Glaucoma. However in severe cases surgery is recommended.