The retina is a crucial part of the human eye, as it is the part that begins processing light into images of the world around us. While the retina is generally well-protected within the eyeball, specific circumstances can cause this multilayered structure to tear and detach, resulting in a variety of symptoms as well as either partial or complete loss of vision in the eye.
Trauma
Blunt force to the eyeball, such as being hit in the eye by a ball or fist, combined with small tears or holes in the retina, may jostle the jelly-like substance within the eyeball (the vitreous). The vitreous may then seep into the hole or tear and come between the retina and the back of the eyeball, causing it to slowly detach from the wall of the eyeball. An analogy is a blob of glue being inserted between a layer of wallpaper and the wall--as the glue accumulates under the wallpaper, it causes the wallpaper to bulge and eventually come away from the wall.
Extreme Nearsightedness (High Myopia)
In people who are extremely nearsighted, the eyeball is more elongated (oval rather than spherical in shape). Additionally, the retinal layer itself is thinner than in people with normal vision. These two factors seem to predispose myopic individuals to spontaneous retinal detachment. The mechanism is similar to that seen with trauma; however, likely because the retina is thinner, it is more vulnerable to developing small holes or tears, which may evolve into partial or complete detachment of the retina.
Marfan Syndrome
Marfan syndrome is rare genetic disease that is characterized by unusually long fingers and toes. It can affect many parts of the body, including the eyes. While the common eye-related complication of Marfan syndrome is abnormal lens placement (instead of being directly behind the iris and pupil it is dislocated toward the upper eye), high myopia may also occur. The high degree of nearsightedness results in a predisposition to retinal tears and detachment.
Retinopathy of Prematurity
Retinopathy of prematurity (ROP) occurs when the blood vessels of the retina do not develop normally. In general, the more prematurely a baby is born, and the less he weighs at birth, the more likely it is that the ROP will be significant enough to threaten normal vision. Retinopathy of prematurity occurs because in a prematurely born baby, the retinal vessels have not yet finished developing and can thus develop abnormally. In this case, there is an increased risk of retinal detachment.
Surgery for Cataract Removal
Cataract is the term used to describe the condition in which the lens of the eye becomes cloudy, or opaque. Removal of the lens is a relatively simple surgery known as cataract extraction; however, one of the possible complications of the surgery, especially in people with a high degree of nearsightedness ("high myopes"), is retinal detachment.
References
- "CURRENT Diagnosis & Treatment: Pediatrics"; William Hay et. al.; 2008
- "Ganong's Review of Medical Physiology"; Kim E. Barrett et. al; 2009
- "Vaughan & Asbury's General Ophthalmology"; Paul Riordan-Eva et. al.; 2007
- "Investigative ophthalmology & visual science"; Retinal nerve fiber layer measurements in myopia: An optical coherence tomography study;CK Leung et. al.; December 2006
