Microbial Diseases of the Eye
By Noel Vance and Teresa Mullings
May 15, 2009


Conjunctivitis and Trachoma




File:Pink eye.jpg
File:Pink eye.jpg
external image Trachoma.jpg
Definition:
Conjunctivitis is a condition where the conjunctiva of the eye is inflamed (Tortora 634). Most people know this condition by its common name, “Pink Eye” or “Red Eye”. The Conjunctiva of the eye is the transparent layer of the eye that covers the white part of the eye and also includes the inner eyelid (American Optometric Association website).

Causes:
Conjunctivitis can be caused by many things. Bacteria, viruses, and allergies can cause this condition. Haemophilus influenzae is the most common bacteria to cause this condition. Adenoviruses are the most common viruses that cause Conjunctivitis (Tortora 635).
However, bacteria and viruses are not the only cause of this condition. According to the American Optometric Association, Conjunctivitis can be caused by chemicals as well. Air pollution, chlorine from swimming pools, and exposure to certain chemicals can cause this condition (AOA website).
Common items can also be a cause of Conjunctivitis. Make-up, clothing, and plastics can also cause irritation (Locatcher-Khorazo 162). Less common, but still a cause of Conjunctivitis is from Chlamydia and Gonorrhea. These types of Conjunctivitis are called Chlamydial Conjunctivitis and Neonatal Gonorrheal Opthalmia (Tortora 636).


Types of Conjunctivitis:
Since the term Conjunctivitis is a broad term, there are specific types when discussing this condition. There are three main types of Conjunctivitis.
1. Allergic Conjunctivitis
2. Infectious Conjunctivitis (This form is caused by bacteria and viruses.)
3. Chemical Conjunctivitis
Along with the different types, one may have either an acute or chronic case of Conjunctivitis. With acute being the most common, chronic is usually a less severe infection, but of long duration (Locatcher-Khorazo 65). When a person has chronic Conjunctivitis, it’s harder to find the cause because so many factors can cause this condition.

external image pink_eye.jpg
http://www.ueseyecare.com/conjunctivitis.htm
Symptoms:
Although there are many symptoms to this condition, not everyone experiences all of them. An overall list of symptoms include: The obvious “pink” discoloration of the eye where the common name was coined from. An itching or burning feeling in either one or both eyes, discharge from infected eye, swollen eyelid, and increased sensitivity to light (AOA website).

According to Wikipedia.com, with Allergic Conjunctivitis, the symptoms are itching and swollen eyelids. Viral Conjunctivitis can cause discharge and itch, and Bacterial Conjunctivitis can cause irritation, discharge and the crusting of the eyelid. Both Bacterial and Viral Conjunctivitis can spread easily from one eye to the other. The Infectious type is also contagious (AOA website). Chemical Conjunctivitis usually doesn’t have the itching symptom.


Treatment:
For Allergic Conjunctivitis, some ways to treat this type is to pour cool water on the face, use artificial tears, and sometimes the use of drugs that treat allergies will help. The use of antibiotics is used with Bacterial Conjunctivitis and viral usually resolves on its own. Chemical Conjunctivitis is sometimes treated with a saline rinse. However in some cases the chemical may have cause a burn that needs medical treatment (Wikipedia Website).
external image Children_PinkEye.jpghttp://bayblab.blogspot.com/2007/11/pink-eye-outbreak.html?showComment=1195500240000
Important Facts to Remember:
Although bacteria are the most common reason for this condition, it is normal for bacteria to be present in the eye. Staphylococcus epidermidis, Staphylococcus aureus, and diphtherods are the three most common types (Locatcher-Khorazo 22). One’s hands, face and respiratory tract are just some of the ways these bacteria can be transmitted to the eye.
There are various ways to reduce one’s risk of contracting this condition. Good personal hygiene and washing hands frequently are just two of the ways to reduce one’s risk. Being that almost everyone has experienced “Pink Eye” in their lifetime, being aware of the risks is critical.


Application to Real Life:
There are everyday things one can do to reduce their risk of getting Conjunctivitis. Along with washing one’s hands frequently, certain items need to be replaced more often than one may think.
For example, almost every woman has some type of cosmetic in their home. Many of us don’t know that these cosmetics have expiration dates. These dates are important because many of these cosmetics can contribute bacteria that can cause conditions like Conjunctivitis.
Mascara 3 months
Liquid Eyeliner 3-6 months
Eye Shadow 2 years (Cosmetics Website)
Along with makeup, many of us wear contact lenses. With more and more contact lenses users, the rate of infections has increased (Tortora 635). In the textbook, it suggests not making your own saline solutions, heat lenses to disinfect, and when heat cannot be used, the use of hydrogen peroxide.
Keep in mind that Conjunctivitis is normally a minor eye infection. However in some cases it can cause a serious problem (AOA website). Simple things like hand washing, discarding old cosmetics, and properly cleaning contact lenses will help reduce one’s risk.





Trachoma


Definition: A serious eye infection, and probably the greatest single cause of blindness by an infectious disease (Tortora 636.) This disaese affects children in third world countries where adaquate healthcare is sparce. Trachoma is cause by the bacteria Chlamydia trachomatis. Africa an Asia see the highest numbers of children affected.

Transmission: Direct hand eye contact as well as fomites and flies via the conjunctiva. Fomite: A nonliving object that can spread infection (Tortora 918.)
Some examples of fomites include
:
external image towel.jpgexternal image handkerchief.jpg
Symptoms and Treatment: Pateints first get infected with the bacteria, then inflammation occurs if infection persists. In the early stages of trachoma the upper eyelids have a red velvetly appearance, interspersed with tiny, bubblelike structures called follices (Jones 196). This leads to a condition known as trichiasis or inturning of the eyelashes. When the patient's eyelashes rub on their cornea, scarring occurs which leads to blindness. Ulcers in pannus may develop which leads to a loss in vision due to the clouding of the cornea (Jones 196). Before blindness happens, those affected can use an oral azithrmycin to treat trachoma. Prolonged treatment with tetracycline anibiotic eye ointment is effective (Jones 196). Also, trichiasis can be corrected with surgery.
external image Active_trachoma_follicles.jpg external image pic019.jpg&width=350

Prevention: The fact that these countries are poor and their people cannot afford healthcare is a big problem. Proper medical care and cleanliness are two ways in which this disease can be avoided. Teaching about hygiene and contagious nature of the disease is important (Jones 196.)


Works Cited

Locatcher-Khorazo. Microbiology of the Eye. St. Louis: The C.V Mosby Company, 1972.

American Optometric Association Website 24 April 2009. http://www.aoa.org/conjunctivitis.xml

Wikipedia Website 24 April 2009.
http://en.wikipedia.org/wiki/Conjunctivitis

Cosmetic Website 25 April 2009. http://cosmetics.suite101.com/article.cfm/makeup_shelf_life


Trachoma picture: http://microbewiki.kenyon.edu/images/8/80/Trachoma.jpg

Towel picture: http://www.neilblevins.com/cg_education/towels_carpet_grass/towel.jpg

Handkerchief picture: http://wirelessdigest.typepad.com/hippyshopper/images/handkerchief.jpg

Trichiasis picture: http://davidlwilliams.org.uk/mysqlscripts/thumbnail.php?pic=../clinicalphotos/pic019.jpg&width=350

Follicles picture: http://www.utdol.com/online/content/images/id_pix/Active_trachoma_follicles.jpg

Case et all. Microbiology an Introduction, San Francisco: Pearaon Benjamin Cummins, 2007.

Jones et all. Medical Care of Refugees, New York: Oxford University Press, 1987.