Can trauma to the eye produce cataract? The answer is yes. There has always been an intimate relation between trauma to the eye or the face and the development of cataract. The cataract that is a result of trauma is called a “traumatic cataract”.
In this article we will talk about the types of trauma that can affect the eye leading to development of a cataract, and the different types of traumatic cataract that can result from each type of trauma to the eye.
What are the types of trauma that can affect the eye?
Trauma to the eye can be classified according to the nature of the offending agent into the following categories:
- Blunt trauma to the eye.
- Penetrating trauma to the eye.
- Chemical injuries to the eye.
- Radiation to the eye.
What is blunt trauma and what is its impact on the eye?
Blunt trauma is a physical trauma affecting part of the body caused by a blunt non-penetrating force or object.
Examples of blunt trauma to the head or the face include: hitting the head or the face with an object such as a stick or a baseball bat, a punch to the face or the eye, head hitting the ground after falling from height, head hitting windshield in car accidents, etc.
Blunt trauma to the eye can lead to lens damage and opacification, resulting in a cataract. The incidence of cataract might be immediately after the accident, or as a late result, or as the sequalae of the blunt trauma.
The impact of the blunt trauma may also include dislocation of the lens from its normal place to any direction (falling back in the vitreous humor; anterior dislocation in the anterior chamber). The blunt trauma might also affect other parts of the eye leading to detachment of part of, or the whole retina, or hemorrhage in the vitreous humor, etc.
Penetrating trauma to the eye
This is the sort of injury in which a sharp object penetrates the different layers of the eye ball. The offending object can be a gun bullet, a piece of glass from a broken windshield in a car accident, a nail, a small piece of metal, etc. The offending object results in a wound to the eye and this condition is called “rupture of the globe”. In such cases, urgent surgical closure and repair of the wound is important.
Foreign bodies that perforate the cornea and reach the lens along its pathway will lead to damage and opacification of the crystalline lens, producing traumatic cataract. The foreign body might completely tear the lens, leading to disruption of the lens capsule and dissemination of the lens material inside the eyeball. The foreign body will cause injury to multiple parts of the eye, such as the cornea, the sclera, the iris, the retina, etc.
Chemical injuries to the eye
Alkali injuries to the eye can produce cataract as well as damaging the structures at the surface of the eye, such as the cornea, the conjunctiva, etc. The cataract is produced because the chemical substance penetrates through the layers of the eye leading to a change in the composition and characteristics of the aqueous humor (the fluid that fills the anterior half of the eyeball).
This change in the aqueous humor surrounding the lens leads to chemical change in the composition of the transparent lens fibers, producing a cataract.
Alkalis tend to produce severe and deep injuries compared to acids as they can penetrate body tissues more easily.
Radiation to the eye
Patients exposed to ionizing radiation in large doses can develop cataracts because the human lens is highly sensitive to ionizing radiation. The dose of the radiation plays an important role in determining the severity of the produced cataract.
Younger patients are more easily affected than older ones because young patients have more active lens cells. Damage of these growing lens cells will produce lens opacities and cataract.
The strange thing is that a very long period of time might pass between exposure to radiation and the development of cataract.