The human eye has two main areas, known as the anterior segment which is in the front and is filled with the aqueous humor, a clear watery fluid and the posterior segment at the back that is filled with the vitreous humor. The usually intraocular pressure, which is the pressure within the eye, is often between 12mmHg and 20mmHg and usually when the intraocular pressure rises in the eye, it leads to number of complex medical conditions with glaucoma being one of them.
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Glaucoma refers to the group of complex conditions that occurs due to the damage of the optic nerve, which mostly happens due to the increase in thee pressure in the eye. However there have been cases where people with low intraocular pressure have also developed glaucoma. There are different types of glaucoma. Given below are some details on the same.
Different Types of Glaucoma
Open Angled Glaucoma
Open angled glaucoma is also referred to as chronic glaucoma and is the most common type of glaucoma to affect people. The open angled glaucoma is very dangerous as its progress is very slow, which means that this condition can go unnoticed for years till it becomes a serious problem. Studies have shown that people with African descent are more susceptible to this type of glaucoma. Open angled glaucoma can further be classified into primary open glaucoma and secondary open glaucoma.
- Primary Open GlaucomaWhile the causes are not clear, this type of glaucoma has shown signs of being related to the mutations that occurs in the MYOC gene that in turn codes for myocilin, which is a protein in the some of the tissues and this includes the trabecular meshwork which is an area in the eye, present near the ciliary body, around the corneal base and it is responsible for draining the aqueous humor through the anterior chamber.
- Secondary Open GlaucomaThis condition occurs when certain foreign particles or cellular derbies or cells blocks the trabecular meshwork thus preventing the outflow of the aqueous fluid. Depending on the type of particles creating the blocks, this type of glaucoma can further be divided into pigmentary glaucoma, melanomalytic glaucoma, exfolication glaucoma and ghost cell glaucoma.
Close Angled Glaucoma
Close angled glaucoma is a condition that arises when there is a physical obstruction in the junction between the cornea and the iris and this obstruction is in most cases caused by the peripheral portion of the iris. This in turn prevents that aqueous humor from being drained thus causing the condition known as close angled glaucoma or angle closure glaucoma. Close angled glaucoma often occurs suddenly and is accompanied with a lot of pain and discomfort. Close angled glaucoma can also be classified into two types, namely primary angle closure glaucoma and secondary angle closure glaucoma.
- Primary Angle Closure GlaucomaThis condition occurs when the flow of the aqueous humor is obstructed by the margin of the iris, however the reason behind this condition is still not known.
- Secondary Angle Closure GlaucomaThis condition is caused when the obstruction is due abnormal growths, particles and fibrotic scarring, which in turn blocks the trabecular meshwork.
Congenital glaucoma is a medical condition that is present in infants at birth and is usually diagnosed shortly after birth, at birth or within the first year of the child’s life. However there have also been cases where the symptoms of this condition have not been recognized until much later. Congenital glaucoma usually occurs due to lack of proper development of the trabecular meshwork thus not letting it function properly. Due to the malfunctioning of the trabecular meshwork, the aqueous humor is not drained out thus causing high pressure within in the eye which in turn leads to glaucoma. This condition is more commonly observed in boys when compared to girls.
Normal Tension Glaucoma
Normal tension glaucoma is also known as normal pressure or low tension glaucoma and in this case, even though the intraocular pressure is not high, the optic nerve is damaged, there by leading to loss in vision. The causes for this condition are still a mystery.
As mentioned above this is a form of secondary open angled glaucoma and here the pigment granules present in the back of the iris, flows towards the drainage canal and clogs them causing the intraocular pressure to rise thus leading to glaucoma.
Some of the other types of glaucoma are Neovasular glaucoma, Irido Corneal Endothelial glaucoma, Traumatic glaucoma and Pseudoexfoliative glaucoma
Causes of Glaucoma
While the exact cause of the glaucoma, especially the primary types is not known some of the risk factors that could lead to glaucoma are ocular hypertension, age, trauma to the eye, chronic use of corticosteroids, Sturge Weber syndrome, diabetes mellitus, tumors in the ciliary area and other eye diseases such as uveitis. Studies have also shown that people who have a family history of this complex condition have almost six percent chances of suffering from glaucoma.
Women often have shallow anterior chambers when compared to men and hence they are three times more susceptible to developing glaucoma. Prolonged use of steroids and central retinal vein occlusion are also known to cause glaucoma. Genetic mutations are also reprehensible for causing this condition. Some studies even show that there is a correlation between hypertension and glaucoma. In some cases congenital conditions also give rise to glaucoma.
Symptoms of Glaucoma
While one of the main symptoms of glaucoma is loss in vision the rate at which this occurs depends on the type of glaucoma. While open angled glaucoma’s symptoms are gradual loss of vision and loss of peripheral vision in advanced stages this is not accompanied with any pain or discomfort. However in the case of close angled glaucoma
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some of the symptoms that the patient might experience are severe eye pain, nausea, vomiting, blurred vision, redness of the eye and halos around lights. The pain that occurs in some cases is sudden in nature. The other symptoms also include high intraocular pressure as well as a mid dilated or fixed pupil. In case of congenital glaucoma, infants often display symptoms such as light sensitivity, enlargement of the eye and excessive tearing.