diease

Dry Eyes


OVERVIEW OF Dry Eyes :

The normal mechanism of the eye is to shed tears. When the eyes are in shortage of tears it might result in dry eyes. Dry eyes also occurs when eyes do not make the right type of tears or tear flim.

It might result in the inflammation the conjunctiva. The conjunctiva is the thin clear tissue that lies over the white part of the eye and lines the inside of the eyelid.

When someone blink a flim of tears spreads over the eye. This keeps the eye’s surface smooth and clear. The tear flim is important for good vision.

The tear film is made of three layers:

  • An oily layer
  • A watery layer
  • A mucus layer

Each layer of the tear film serves a purpose:

The oily layer is the external covering of the tear flim.  It makes the tear surface smooth and keeps tears from drying up too quickly. This layer is made in the eye’s meibomian glands.

The watery layer is the middle of the tear flim. It makes up most of what we see as tears. This layer cleans the eye, washing away particles that do not belong to the eye. This layer comes from the lacrimal gland in the eyelids.

The medical term used for dry eyes is Xerophthalmia

The mucous layer is the inner layer of the tear flim. This helps to spread the watery layer over the eye’s surface keeping the eye moist. Without mucus, the tears would not stick to the  eye and inside your eyelids.

Normally, our eyes constantly make tears to stay moist. If our eyes are irritated, or we cry, our eyes make a lot of tears. But, sometimes the eyes don’t make enough tears or something affects one or more layers of the tear film. In those cases, we end up with dry eyes.

 


CAUSES :

  • Being in smoke, wind or a very dry climate
  • Looking at the computer screen for prolong time
  • Certain diseases such as rheumatoid arthritis, sjogren’s syndrome and thyroid disease and lupus erythematosus
  • Being in smoke, wind or a very dry climate
  • Using contact lenses for a long time
  • Having refractive eye surgery such as LASIK
  • Taking certain medicines, such as:
  • Diuretics (water pills) for high blood pressure
  • Beta-blockers, for heart problems or high blood pressure
  • Allergy and cold medications(antihistamines)
  • Sleeping pills
  • Anxiety and antidepressant medicines
  • Heartburn medicines


PATHOPHYSIOLOGY :

When allergens or triggering fcators enters the tear flim, it triggers the conjunctival mast cells that bear the IgE antibodies.

Calcium enters the cell

Degranulation of mast cells results in production of Histamine

Histamine release causes Vasodilatation and oedema and resulting reddishness and swelling of the eyes and result in xerophthalmia


ROUTES OF TRANSMISSION :

Xerophthamia occurs by the exposure to contaminated air and water.  It also spreads by bare exposure of eye to environment


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).
  • Blepharitis( when eyelids are swollen and red)
  • Entropian ( when eyelids are turn in) ectropian ( eyelids turn outward)


DIAGNOSTIC :

  • External examination of the eye, including lid structure and blink dynamics.
  • Evaluation of the eyelids and cornea using bright light and magnification.
  • Measurement of the quantity and quality of tears for any abnormalities. Special dyes may be put in the eyes to better observe tear flow and to highlight any changes to the outer surface of the eye caused by insufficient tears.
  • Patient history to determine the symptoms, when the symptoms began, and whether any general health or environmental conditions are contributing to the problem.
  • Visual acuity measurements to determine whether vision has been affected.
  • Evaluation of the conjunctiva and external eye tissue using bright light and magnification.
  • Evaluation of the inner structures of the eye to ensure that no other tissues are affected by the condition.
  • Supplemental testing, which may include taking cultures or smears of conjunctival tissue. This is particularly important in cases of chronic conjunctivitis or when the condition is not responding to treatment.

Cytology scraping:

Ophthalmologist acquires the scraping from the conjunctiva and see those abnormalities using microscopy.

  • Polymerase chain reaction:

This is done by the amplification of the DNA of the infectious agents.

  • Direct fluoresecense monoclonal antibody test:

The smears obtained from the conjunctiva are stained and results are examined.

 


TREATMENT AND PROGNOSIS :

The main aim is to restore or maintain the normal amount of tears in the eye to minimize dryness and related discomfort and to maintain eye health.

Adding tears:

This treatment can be used as often as needed to supplemental natural tear production. There are counter artificial tear solutions which can be used in xerophthalmia.

Conserving tears:

Keeping the natural tears in the eyes longer can reduce the symptoms of the dry eyes. This can be done by blocking the tear ducts through which the tears normally drain. The tear ducts can be blocked with tiny silicone or gel like plugs that can be removed if needed. A surgical procedure can permanently close the tear ducts. In either case, the main aim is to achieve available tears in the eye longer to reduce problems related to dry eyes.

Increasing tear production:

The physician might prescribe eye drops that increases tear production. Taking an omega 3 fatty acid nutritional supplement.

Treating the contribution eyelid or ocular surface inflammation:

Warm compresses and lid massage or eyelid cleaners to aids decrease inflammation around the surface of the eyes.

Viral:

This treatment can be resolve on its own and it does not require any specific treatment.

Antihistamines such as diphenhydramine or Mast cell stabilizer such as Cromolyn sodium might provide effective results against conjunctivitis.

 Allergic:

Cool water can be poured over the face with face inclined downwards which might result in constriction of capillaries, and artificial tears which might sometimes relieve discomfort in mild cases. In more severe cases nonsteroidal anti inflammatory and  antihistamines can be prescribed.

Bacterial:

It usually resolves without the treatment. Topical antibiotics can be given if medications does not provide any improvement after 3 days. Contact lenses might also causes relief of symptoms. Gonorrhoel or chlamydial infections might require both oral and topical antibiotics.

Fluroquinolones, sodium sulfacetamide or trimethoprim/polymyxin may be used typically 7-10 days.

Chemical:

Conjunctivitis due to chemical reactions can be treated via irrigation with the Ringer’s lactate or saline solution.  Chemical injuries particularly alkali burns are medical emergencies as they can lead to severe scarring and intraocualr damage.

 


PROGNOSIS :

Dry eyes can resolve within 5-7 days in 65 % of cases if the triggering factors are removed. 

. And the prognosis is completely dependant on the causative factor.

 


PREVENTION :

  • Don't touch your eyes with your hands.
  • 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 :

The tear promoting drops might contains glycerine, carboxymethylcellulose, dextran, polyethylene glycol, polysorbate, propylene glycol.