Cataract and Glaucoma are two major disease forms affecting the eyes that are increasingly prevalent in the population. Cataract is the leading cause of blindness, directly followed by Glaucoma.
Cataract: This is a progressive clouding or blurring of the eyes’ lens. As the ‘cloudiness’ increases, vision decreases. To the patient, what he or she sees may be perceived as misty, blurred or as viewed through a veil or foggy window. With the lens increasingly becoming opaque, cataract will eventually lead to blindness. Progression of cataract is generally slow. There are different types of cataract, and it can develop due to a range of factors.
Types and causes:
- Age-related cataract: This is the most common form of cataract. While this type can develop as early as in the early 40’s, as progression is slow, vision may only become impaired in later decades (60+years). Protein clumping in the eye is considered the causative factor of this form of cataract.
- Congenital cataract: Genetically inherited cataract is passed on through generations as a predisposition, or is a ‘side-effect’ of other hereditary dispositions such as atopic dermatitis, ichthyosis, or congenital diabetes.
- Secondary cataract: Diseases such as diabetes or hypertension, or specific medication, as for example corticosteroids can be the source of a cataract.
- Traumatic cataract: This is a form of cataract that develops due to an injury or trauma to the eye, or forms following surgery on the eye, as for example in an operation for glaucoma.
Cataract is treatable, in most cases, by surgery, whereby the natural blurred lens is removed and replaced by a clear artificial lens.
Glaucoma: This is an irreversible damage to the optic nerve, and a consequential injury caused by an elevated intraocular pressure. In Glaucoma the levels of the intraocular fluid that circulates in the eye fluctuate due to some forms of drainage impairment. The intraocular fluid needs to drain out of the eye through an outflow. In the case of an overproduction of this aqueous humor, a partial or total blockage of the eyes’ drainage channels, the fluid circulation is inhibited and pressure in the eye is increased.
The progression of glaucoma is gradual, however, once a loss of vision is noticed, the disease is already irreversibly advanced. Treatment can only slow progression. Eventually Glaucoma leads to blindness. Patients see ‘blind spots’ in their visual field. It is a hereditary disease. There are different types of glaucoma.
Types and causes:
- Open-angle glaucoma: This type develops gradually, yet, once symptoms are noticed, progression is already significant. This is the most common form of glaucoma. This type of gradual increase of the intraocular pressure is characterized by central or peripheral ‘blind spots’ in the field of vision. In this type, the anatomy of the drainage channels is normal.
- Closed-angle glaucoma: The intraocular fluid, in this type, cannot circulate properly and drainage is blocked. This form, as compared to the ‘open-angle’ type, occurs suddenly and rapidly. This form of glaucoma may be associated with discomfort and pain. This sudden increase in intraocular pressure is a medical emergency.
- There are further forms, such as normal-tension glaucoma, where neural damage occurs albeit the intraocular pressure not being elevated. The exact cause of this type is not known. Infant glaucoma is a type that develops at birth or in early age. This may be due to blocked drainage channels, or another health condition. Pigmentary glaucoma is caused by gradual blocking of the drainage ways due to pigmentary deposits from the eye that causes an intermittent increase in the intraocular pressure.
Surgery for glaucoma is aimed at opening the drainage channels. It can however not remove the cataract.
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