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What is Glaucoma?

 

Glaucoma is a serious eye condition, which presents as a painless, gradual loss of vision. The detrimental effect caused by glaucoma is a permanent decrease of vision or irreversible blindness. However, if detected in the early stages, loss of vision can be avoided by appropriate treatment.

Glaucoma is the leading cause of blindness among people above the age of 40, the loss of vision cannot be restored, but only further damage can be prevented

Our eye consists of a watery fluid called Aqueous, that takes care of the structures present in the eye. This fluid is continuously produced in the eye and is drained out through a channel. In patients with  Glaucoma, this fluid is not able to drain out thereby increasing the pressure inside the eye, called Intraocular Pressure (IOP), resulting in direct damage to the optic nerve. 

Glaucoma 

Aqueous Flow

What are the causes for Glaucoma?

Who is at risk of developing Glaucoma?

  • It mainly develops in people above the age of 40 but Glaucoma can affect anyone. It is highly advised to have regular eye checks (Frequency: At least once a year) for people above the age of 40.

  • Diabetic Patients

  • Patients with family or genetic history of Glaucoma.

  • People with hypertension problems (BP)

Common symptoms of Glaucoma.

  • Painless, gradual decrease in vision that rarely develops symptoms in the early stages.

  • Frequent change of spectacle number

  • Headaches and pain in the eyes. 

Difference between Glaucoma and Cataract

Eye with glaucoma

Normal Eye

Cataract

Glaucoma

Glaucoma and Cataract both cause a painless gradual loss of vision, but the major difference between the two is that Cataract can be treated and vision can be restored and in the case of Glaucoma, the loss of vision cannot be restored, only controlled.

Cataract can only be treated by surgery, with a safe and effective method called as phacoemulsification/MICS, which consists of modern techniques to make this procedure minimally invasive.

Glaucoma can be treated in its early stages by eye drops and medication, that reduce the pressure in the eye and help in draining out of Aqueous and reducing IOP. If Glaucoma progresses, it can only be treated with surgery, which  prevents the further damage of the optic Nerve.

Types of Glaucoma

Open Angle Glaucoma

Open Angle also known as Primary Open Angle Glaucoma , is the most common type of Glaucoma that appears in patients. The primary reason for this type of Glaucoma is the clogging of drainage canals over time. This increases the pressure in the eye or IOP (IntraOcular Pressure) which causes detrimental effects on the optic nerve.

It is of high priority to get diagnosed by an eye surgeon as open angle Glaucoma does not show early symptom and only begins to appear once considerable damage has been caused to the vision. This type of Glaucoma, if detected in the early stages, can be treated by the use of medication and a good amount of vision loss can be prevented.

Open angle Glaucoma

Angle Closure Glaucoma / Acute Glaucoma / Narrow Angle Glaucoma

 

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This type of Glaucoma is referred to by multiple names such as Angle Closure Glaucoma, Acute Glaucoma, Narrow Angle Glaucoma and is a rare condition when compared to other types of Glaucoma. In this condition, the eye pressure rises very quickly and causes symptoms like sudden headaches, acute eye pain, blurry vision and rainbows around lights that feels much like an attack that persists over time.

In Angle Closure, the drainage channels get blocked and do not allow any fluid to pass through. This results in immediate increase in the Intraocular pressure. This condition is usually considered as a medical emergency and requires immediate attention by an eye surgeon. The treatment consists initially reducing the pressure by medication and then treatment by laser or a surgery where the surgeon releases the pressure instantly and prevents further damage to the optic nerve.  

Narrow Angle Glaucoma

Normal Tension or Low Tension Glaucoma

Normal Tension Glaucoma (also known as normal-pressure glaucoma, low-tension glaucoma or low-pressure glaucoma) is a condition where a patient with normal IOP or Low IOP develop Glaucoma eventually resulting in damage to the vision. This is a condition that had limited reasoning for what exactly happens in the eye.

The treatment for Normal Tension Glaucoma is similar to an Open Angle Glaucoma in most cases. As there is no specific cause for this type of Glaucoma, doctors are of the opinion that it may be caused due to family history or less blood supply to the optic nerve.

There are a few more types of Glaucoma like

​​

1. Childhood Glaucoma (Congenital)

2. Secondary Glaucoma

What are the tests for Glaucoma?

The tests done to detect the presence of Glaucoma and the severity of damage to the vision are: ​

1. Tonometry - The tonometry test is done to measure the pressure of the eye by the use of a special device.

2. Ophthalmoscopy - Ophthalmoscopy is a test to determine the status of the optic nerve and retina of the eye. It is conducted by an instrument called the ophthalmoscope.

3. Perimetry - Perimetry is a test used to detect the field of vision. Glaucoma can cause considerable damage to your peripheral field of vision and this test detects maps of your vision field, providing information about the typical damages done by Glaucoma.

4. Gonioscopy - Gonioscopy is a test that determines the condition of the drainage channels and provides more information about the type of Glaucoma present in the patient.

5. Pachymetry OCT - Pachymetry is a test to determine the thickness of your Cornea. Corneal thickness is an important part in the measurement of your eye pressure. A thicker or thinner cornea can alter the eye pressures, forcing the doctor to treat you for ailments that might not be relevant to you. This test lets your doctor evaluates the pressure accurately, thus prescribing pertinent treatments for your condition.

6. OCT Optic Nerve Analysis - The OCT Optic Nerve analysis measures the thickness of the Optic Nerve to detect the presence of Glaucoma. This instrument is based on a method called optical coherence tomography which provides contour map images of the optical nerve and optic cup that allows the doctor to determine the thickness of the nerve.

Tonometry

Perimetry

Gonioscopy

Treatment for Glaucoma

Any medication or surgery cannot restore your vision that has already been compromised by Glaucoma. All treatments for Glaucoma are majorly focussed towards protecting the eye from further damage and maintaining your existing vision

Medication

1. In early stages of Glaucoma, medications like eye drops can be prescribed. To treat Glaucoma, a series of medications can be prescribed to control the IOP to a normal level or decrease the production of the fluid inside the eye.

2. The newer medications that are available not only reduce the eye pressure but also increase the blood flow to the optic nerve.

Surgery

Laser Procedure

Laser trabeculoplasty is a type of laser treatment done to drain fluid out of the eye. The surgery begins by pouring numbing drops to your eye.  A high-intensity laser beam is used to drain the fluid. This efficiently allows the fluid to drain but is a temporary solution and may have to be repeated if the condition persists

Trabeculectomy or Conventional Surgery

A conventional surgery, also known as Trabeculectomy, is done when the medications and laser procedures are not controlling your eye pressure. This surgery entails creating a new drainage flap inside your eye to drain out the fluid. The built up fluid passes through this flap and drains into the vascular system. 

 

Glaucoma Shunts

Glaucoma Shunts or Implants are devices that are made of silicon and tubular in structure, inserted in the eye to drain out fluid. In advance cases of Glaucoma, Shunts are used where the above treatments have failed.

Laser Treatment

Trabeculectomy

Glaucoma Shunts