Glaucoma is the condition that causes optic nerve damage and affects the vision. Glaucoma damages the optic nerve at the point where it leaves the eye.
When a person looks at something, light passes through the front of the eye, focused by the lens onto the retina. Light is converted into electrical signals by a delicate light sensitive tissue known as retina. These signals are delivered by a delicate network of nerves from the different parts of the retina to the optic nerve and then it is passed onto the brain. Brain interprets these signals to enable a person to see the world around him. Nerves leave the eye at a point known as the optic disc.
Eye pressure has been shown to be a major risk factor for optic nerve damage according to the many large clinical studies conducted. In the front eye, there is a space called the anterior chamber which has a clear fluid flowing continuously in and out of this chamber and nourishing the nearby tissues. The fluid leaves the chamber at an open angle where the cornea and iris meet. The moment the fluid reaches the angle, it flows down through a spongy meshwork, and is drained out of the eye.
In open-angle glaucoma, despite the drainage angle being open, the flow of fluid through the meshwork drain is too slow. Owing to the buildup of fluid, the pressure inside the eye rises to a level at which it can cause the damage to the optic nerve. When the optic nerve is damaged from increased pressure, open-angle glaucoma-and vision loss—may result. That’s why controlling pressure inside the eye is important.
Blood pressure is another risk factor for optic nerve damage. Thus, it is also important to ensure that the blood pressure is monitored properly.
The following factors can increase the risk for developing glaucoma:
- Glaucoma risk increases slightly as a person ages. People over 60 years of age are at an increased risk for glaucoma. African Americans, however, are at increased risk after age 40.
- Having a family history puts an individual at an increased risk of developing glaucoma.
- Medical conditions such as diabetes, heart disease and high blood pressure may increase glaucoma risk.
- Physical injuries such as a severe trauma to the eye, can result in immediate increased eye pressure and internal damage from such a trauma can also result in increased pressure to the eye. Dislocation of the lens may occur due to injury which can lead to a closure of the drainage angle and in turn increasing the pressure.
- Other eye-related risk factors. Certain features of eye anatomy, such as optic nerve sensitivity and thinner corneas, point to an increased risk for developing glaucoma. Glaucoma could also be triggered by the conditions such as eye tumors, retinal detachment and eye inflammations. Some studies suggest that high amounts of nearsightedness may also be a risk factor for glaucoma.
- Use of corticosteroids for extended period is known to have put people at risk of developing secondary glaucoma.
The signs and symptoms of glaucoma vary depending on the type and stage of your condition. For example:
- Patchy blind spots in peripheral or central vision, frequently in both eyes
- Tunnel vision in the advanced stages
- Acute angle-closure glaucoma
- Severe headache
- Eye pain
- Nausea and vomiting
- Blurred vision
- Halos around lights
- Eye redness
If left untreated, glaucoma will eventually result in blindness. Despite treatment, the prevalence of blindness amongst people with glaucoma is about 15 percent in at least one eye within 20 years.
Glaucoma is an outcome of the optic nerve damage. Gradual deterioration of optic nerve results in the development of blind spots in the visual field. For reasons not fully known, this nerve damage is usually related to an increased eye pressure.
Elevated eye pressure is due to a buildup of a fluid called aqueous humor. This fluid normally drains into the front of the eye through tissue at the angle where the iris and cornea meet. When fluid is overproduced or the drainage system doesn’t work properly, the fluid can’t flow out at its normal rate and pressure builds up.
Glaucoma tends to run in families. In some people, scientists have identified genes related to high eye pressure and optic nerve damage.
The types of glaucoma include the following:
Open-angle glaucoma is the most common form of the disease. In this disorder, there is a partial blocking of trabecular meshwork while the drainage angle which is formed by the cornea and iris remains unblocked. This results in increase in the eye pressure, which may result in the optic nerve damage. It happens so slowly that you may lose vision before you’re even aware of a problem.
Angle-closure glaucoma is due to the forward bulging of the iris that narrows or blocks the drainage angle formed by the iris and cornea. Due to this the fluid is unable to circulate through the eye, resulting in increased pressure. People with narrow drainage angles, are at increased risk of angle-closure glaucoma.
Angle-closure glaucoma could be sudden or may develop gradually. It is a medical emergency and sudden pupil dilation could trigger it.
Optic nerve is damaged in normal-tension glaucoma, despite the eye pressure remaining within the normal range. Reason for this occurrence remains unknown. This could be due to the sensitive optic nerve or less blood being supplied to the optic nerve. Either atherosclerosis (the buildup of fatty deposits or plaques) or other conditions that impair circulation could be the cause of this limited blood flow.
Glaucoma in children
It’s possible for infants and children to have glaucoma. It may be present from birth or developed in the first few years of life. The optic nerve damage may be caused by drainage blockages or an underlying medical condition.
Build-up of pigment granules from the iris occurs in the drainage channels in the pigmentary glaucoma, slowing or blocking fluid exiting the eye. Sometimes stirring up of the pigment granules occurs due to jogging, depositing them on the trabecular meshwork and resulting in intermittent pressure elevations.
Glaucoma is diagnosed with a comprehensive eye examination. As glaucoma is a progressive disease, meaning it worsens over time, a loss of nerve tissue, a change in the appearance of the optic nerve, and a corresponding loss of vision confirm the diagnosis. Some optic nerves may resemble nerves with glaucoma, but the patients may have no other risk factors or signs of glaucoma. These patients should have routine comprehensive exams to monitor any Patient history to determine any symptoms the patient is experiencing and if there are any general health problems and family history that may be contributing to the problem.
Glaucoma testing includes:
- Patient history to determine any symptoms the patient is experiencing and if there are any general health problems and family history that may be contributing to the problem.
- Visual acuity measurements to determine if vision is being affected.
- Tonometry to measure the pressure inside the eye to detect increased risk factors for glaucoma.
- Pachymetry to measure corneal thickness. People with thinner corneas are at an increased risk of developing glaucoma.
- Visual field testing, also called perimetry, to check if the field of vision has been affected by glaucoma. This test measures your side (peripheral) vision and central vision by either determining the dimmest amount of light that can be detected in various locations of vision, or by determining sensitivity to targets other than light.
- Evaluation of the retina of the eye, which may include photographs or scans of the optic nerve, to monitor any changes over time.
- Supplemental testing, which may include gonioscopy. This procedure offers a view of the angle anatomy, which is where eye fluid drainage occurs. An alternative test is serial tonometry . This procedure requires several pressure measurements taken over a period of time, which look for changes in the eye pressure throughout the day. In addition, devices can be used to measure nerve fiber thickness and to look for tissue loss on specific areas of the nerve fiber layer.
Glaucoma treatment is aimed at reducing pressure in the eye. Daily use of prescription eye drops is the first line treatment that is most commonly used. In some cases, laser treatment, medications, or surgery may be required. While there is not yet a cure for glaucoma, early diagnosis and continuing treatment can preserve eyesight.
- Medications. A number of medications are currently available to treat glaucoma. Typically, medications help reduce the increased eye pressure. This could be prescribed either singly or in a combination.
- Surgery. Procedures include laser treatment, making a drainage flap in the eye, inserting a drainage valve, or destroying the tissue that creates the fluid in the eye. All procedures aim to reduce the pressure inside the eye when medication is not sufficient. Surgery cannot reverse vision loss.
- Laser surgery. Laser trabeculoplasty helps in draining the fluid out of the eye. A high-energy laser beam helps in stimulating the structure that is responsible for draining the fluid from the eye so that the draining of fluid occurs more efficiently. The results may be somewhat temporary, and the procedure may need to be repeated in the future.
- Conventional surgery. If laser surgery and eye drops fail to control eye pressure, a trabeculectomy may be required. A drainage flap is created due to this filtering microsurgery. This allows for the fluid to seep into the flap and drain into the vascular system eventually.
- Drainage implants. For adults with uncontrolled glaucoma or secondary glaucoma and children with glaucoma, an alternate option could be a drainage valve surgery. A small silicone tube is inserted in the eye to help drain fluid.
Galucoma treatment in India at Sanjeevan focuses on the improvement of the health of the ciliary body. The ciliary body is responsible for the production of aqueous humor, the dysfunction of which increases the intra ocular pressure and causes Glaucoma. The treatment ultimately stimulates the drainage of aqueous humor. The treatment also improves the conditioning of the optic nerve and the health of the optic disc which improves the peripheral vision in patients suffering from Glaucoma.