diease

Keratitis


OVERVIEW OF Keratitis :

 The cornea gets inflamed and it gets irritated.

 


STRUCTURE of Keratitis :

Structure of an eye:

Iris:

It is pigmented muscular layer which is present between the cornea and lens and it controls the amount of light entering the eye.

Sclera:

It is termed as the white structure of the eyes and it supports the eyeball and cornea.

Cornea:

It is the clear surface of the eye which allows the light to pass through it and it directly covers the iris and pupil providing a layer of protection.

Lens:

It is located behind the iris and it is the part of the eye which aids in focus. The lens can change the shape to alter the focal distance of the eye and focuses the light rays that pass through the retina at a right angle. In aged peoples protein gets buildup in the lens giving rise to cataract. In the treatment of cataract the physician might removes the lens and replaces it with new one.

Aqueous humour:

It is a watery fluid that the eyes constantly produces in order to maintain the good pressure in the eye and lso the aqueous humour might provides the nutrient supply to the  cornea.

Ciliary muscle:

The ciliary muscle actually changes the shape of the lens and make them focus properly. It maintains the lens in the coorect position in the eye’s middle layer and regulates the flow of aqueous humour within the eye.

Extraocular muscles:

The extraocular muscles include medial rectus, lateral rectus, superior oblique, inferior oblique, superior rectus and inferior rectus. The medial rectus is the largest of the all the six extraocular muscles. It makes the pupil to be in the median state that is towards the nose and it make sure that the eyes are aligned correctly. If there are any problems with the medial rectus it can lead to the strabismus.

Lateral rectus muscle:

It helps in the lateral movement of the eyes. If there is any problem with this muscle one might experience estropia.

Retina:

It is present at the back of the eyes. The main function of the retina is to collect the information from the lens and send it to the brain for visualization. There are 2 photoreceptors on the retina A) Rods B) Cones.  Rod are responsible for the dark and light, picking up on motion and cones are responsible for the colour vision. Problems within the retina results in loss of vision.

Choroid: 

This is a major blood vessel which sits between the retina and the sclera at the back of the eye. It nourishes the outer layers of the retina and keeps the eye at the right temperature. It also provides the right amount of oxygen and blood flow to the retina, helping the eye to function well.

Macula:

It is the center part of the retina .  macular regeneration might result in loss of vision.

Optic nerve:

The optic nerve is the mediator friendly which transmit the signals from the retina to the brain. It consists of million of nerve fibers and it is considered as the part of the central

nervous system. Glaucoma might cause severe damage to the optic nerve

Vitreous humour:

 The vitreous humour is a liquid in your eye with the consistency of gel, and sits behind your lens but in front of your retina. If any substances enter the vitreous humour, they are referred to as floaters.

Causes:


CAUSES :

Bacterial :

It is caused by staphylococcal or streptococcal bacteria from your own skin or respiratory system. Insects, physical contact with other people, poor hygiene (touching the eye with unclean hands), or using contaminated eye makeup and facial lotions can also cause the infection. Sharing makeup and wearing contact lenses that are not your own or are improperly cleaned can also cause bacterial keratitis

Viral conjunctivitis is most commonly caused by contagious viruses associated with the Herpes simplex virus.Viral conjunctivitis can also occur as the virus spreads along the body's own mucous membranes, which connect the lungs, throat, nose, tear ducts and cornea. Since the tears drain into the nasal passageway, forceful nose blowing can cause a virus to move from your respiratory system to your eyes.

Injury:

If any object scratches or injures the surface of your cornea, noninfectious keratitis may result. In addition, an injury may allow microorganisms to gain access to the damaged cornea, causing infectious keratitis.

Contaminated contact lenses:

Bacteria, fungi or parasites — particularly the microscopic parasite acanthamoeba — may inhabit the surface of a contact lens or contact lens carrying case. The cornea may become contaminated when the lens is in your eye, resulting in infectious keratitis. Over-wearing your contact lenses can cause keratitis, which can become infectious.

Contaminated water:

Taking bath or exposure to contaminated water in ponds , well and others might result in conjunctivitis.

 


COMMON CLINICAL SIGNS AND SYMPTOMS :

  • the feeling that some irritants in the eye or some gritty sensation in the  eye
  • red eyes
  • burning eyes
  • itchy eyes
  • watery eyes
  • puffy eyelids
  • blurry hazy vision
  • being extra sensitive to light
  • lots of mucus, pus, or thick yellow discharge from the eyes. There can be so much that your eyelashes stick together (usually with bacterial conjunctivitis).


DIAGNOSTIC :

Visual acuity test:

This is a fancy way of saying "eye chart exam."  The physician might ask you to read the letters from the distance.

Slit-lamp exam:

 The physician uses a special microscope with a bright light and examine the different parts of your eye. They might examine at your cornea, the clear outer layer. They'll also examine the iris  the colored part of your eyeand the lens that sits behind it. The lens bends light as it enters your eye so you can see things clearly.

Retinal exam:

The physician drops in your eyes to widen your pupils, the dark spots in the middle that control how much light gets in. This lets them get a good look at the retina.

Penlight exam:

The physician may examine your eye using a penlight, to check your pupil's reaction, size and other factors. Your doctor may apply a stain to the surface of your eye, to help identify the extent and character of surface irregularities and ulcers of the cornea.


TREATMENT AND PROGNOSIS :

Bacterial keratitis:

 For mild bacterial keratitis, antibacterial eyedrops may be all you need to effectively treat the infection. If the infection is moderate to severe, you may need to take oral antibiotics to get rid of the infection.

Fungal keratitis:

 Keratitis caused by fungi typically requires antifungal eyedrops and oral antifungal medication.

Viral keratitis:

If a virus is causing the infection, antiviral eyedrops and oral antiviral medications may be effective. Other viruses need only supportive care such as artificial tear drops.

Acanthamoeba keratitis:

 Keratitis that's caused by the tiny parasite acanthamoeba can be difficult to treat. Antibiotic eyedrops are used, but some acanthamoeba infections are resistant to medication. Severe cases of acanthamoeba keratitis may require a cornea transplant.

Inflammatory Keratitis:

The inflammatory keratitis is treated with the corticosteroids.

 


PREVENTION :

  • Don't touch your eyes with your hands.
  • Avoid exposure to the contaminated water with eyes
  • Avoid using contact lenses
  • Wash your hands often.
  • Use a clean towel and washcloth daily.
  • Don't share towels or washcloths.
  • Change your pillowcases often.
  • Throw away your eye cosmetics, such as mascara.
  • Don't share eye cosmetics or personal eye care items.


Medicines used in the Treatment :

Corticisteriods

Cefotaxime

Itraconazole