Bacterial Keratitis

Useful Terms

Bacterial keratitis = infection or inflammation of the cornea caused by bacteria

Superficial keratitis = infect of the uppermost layers of the cornea

Deep keratitis = infection of the deeper layers of the cornea

Amoebic keratitis = infection of the cornea that most often occurs with those who contact lenses

Fungal keratitis = infection of the cornea due to fungi

Viral keratitis = infection of the cornea resulting from viruses

Photokeratitis = infection that results from exposure to concentrated UV radiation; also known as snow

blindness, arc eye, and welder’s flash, among other names

Common Symptoms

  • Pain in the eye often comes suddenly and unexpectedly
  • Poorer vision
  • Increased sensitivity to light
  • Severe tearing
  • Excessive discharge from the eye

Causes

  • Contact Lenses
    • Improper disinfecting
    • Usage of them while swimming
    • Wearing them for longer periods of time than recommended
    • Usage of water or a homemade solution as a means of storage and cleaning
    • Keratitis is more common in those people who wear contact lenses continuously,compared to those who wear daily contact lenses and take them out during the nighttime
  • Compromised Immune System
    • When the immune system is weakened because of other diseases and/or medications,the body becomes more vulnerable to contracting keratitis
  • Warm/Hot Climate
    • With a temperate and humid climate comes a greater chance of contracting thecondition of keratitis
    • This is complemented by the direct contact of plant material with the eyes
      • The plant material itself could scratch the epithelium (the barrierthat protects the cornea from bacterial infection)
      • The chemicals that come from the plant could inflame the eyes uponthat contact, which would then lead to an infection
  • Corticosteroids
    • Those same eyedrops that help with the treatment of eye allergies may in factincrease the risk of contracting keratitis or exacerbating already existing keratitis
  • Previous Eye Injuries
    • If the cornea has been previously damaged or compromised from any previous injuriesor maladies, then the risk of contracting keratitis will increase
  • Causes of Bacterial Keratitis
    • Staphylococcus Aureus
    • Pseudomonas Aeruginosa(in those cases that contact lenses are worn)
  • Cause of Amoebic Keratitis
    • Acanthamoeba
  • Causes of Viral Keratitis
    • Herpes Simplex
    • Herpes Zoster

Diagnosis

  • Review of family medical history
  • The ophthalmologist will perform a routine eye exam and use the usual eye charts (ex. readingletters at certain distances) to test for visual acuity and clarity
  • The doctor may also use a penlight to check for the pupil’s reaction to the exposure tolight, its size, and other factors.
  • There may be a stain applied to the eye in order to look for any surface irregularities and/orulcers that may exist in the cornea
    • Then, the extent and nature of those irregularities will be identified
  • Slit Lamp Microscope
    • As with the diagnosis procedure for eye allergies, the slit lamp microscope alsoproves useful here
    • It emits a slit-like beam of light in order to illumine various parts of the eye,such as the cornea, lens, iris, and the space between the iris and cornea
    • These areas are greatly magnified to look for the extent and nature of thekeratitis in the eye and how it may impact the other areas within the eye
  • Laboratory Analysis
    • The ophthalmologist may take a sample of the tears or cells within the cornea andtest it with laboratory equipment to determine what caused the keratitis so as to develop an appropriate treatmentplan

Treatment

  • Bacterial keratitis usually spreads rapidly and may cause blindness if left untreated
  • When superficial keratitis has been healed, there is no scar left on the cornea
  • When deep keratitis is healed, there could be a scar left that may or may not impact vision, whichis contingent on the location of the scar in question
  • In those cases in which the keratitis is noninfectious, the treatment method varies depending onthe cause of the disease:
    • Fort hose situations in which it is caused by a scratch in the cornea or extensivewearing and usage of contact lenses, it requires nothing more than patching for 24-hours and some topical eyemedications.
  • As with the noninfectious keratitis, the treatment for infectious keratitis relies on the cause ofthe disease:
    • Bacterial Keratitis
      • If the disease is mild in nature, then all it takes is the usage ofsome antibacterial eyedrops for successful treatment
      • If the disease ranges from moderate to severe in nature, then itmay require the use of oral antibiotics to eliminate the infection
    • Fungal Keratitis
      • Requires the usage of antifungal eyedrops and oral antifungalmedication, similarly to the treatment for bacterial keratitis
    • Viral Keratitis
      • Again, similarly to the treatment for bacterial and fungalkeratitis, antiviral eyedrops and oral antiviral medications can be successful in treating it
      • However, the medications may not be enough to completely eliminatethe disease and it may come back again
    • Amoebic Keratitis
      • This may be the most difficult form of the disease to treat
      • Antibiotic eyedrops could prove to be effective, but unfortunately,some of these infections could be too resilient or even impervious.
      • The more severe forms of this particular keratitis may obligate acornea transplant
  • If any form of the keratitis infection resists medication as a means of treatment, or it causespermanent damage to the cornea that results in the severe weakening of vision, it is highly recommended to seek acornea transplant