Ophthalmology- the science dealing with the eye and its disorders.
The word ophthalmology comes from the Greek word ophthalmos meaning eye and logos meaning word; ophthalmology means “The science of Eyes” Ophthalmology is the branch of medicine which deals with the diseases of the eye and their treatment.

Some Diseases of Eye & their symptoms-
1. Mucopurulent conjunctivitis- It is the most common type of acute bacterial conjunctivitis characterized by marked conjunctival hyperaemia and mucopurulent discharge from the eye.
Symptoms-
1 Mucopurulent discharge from the eyes
2 Sticking together of lids margins with discharge during sleep
3 Mild photophobia i.e. difficulty to tolerate light
Slight blurring of vision due to mucous flakes in front of cornea

2. Angular conjunctivitis- It is type of chronic conjunctivitis characterized by mild grade inflammation confined to the conjunctiva and lid margins near the angles associated with maceration of the surrounding skin  
Symptoms-
1 Irritation, smarting sensation and feeling of discomfort in the eyes.
2 History of collection of dirty-white foamy discharge at the angles
3 Redness in the angles of eyes

3. Corneal ulcer-It may be defined as discontinuation in normal epithelial surface of cornea associated with necrosis of the surrounding corneal tissue Pathologically it is characterized by odema & cellular infiltration
Symptoms-
1 Pain occurs due to mechanical effects of lids & chemical effects of toxins on the exposed nerve ending
2 Watering from the eye occurs due to reflex hyperlacrimation
3 Blurred vision results from corneal haze
4 Redness of eyes occurs due to congestions of circumcorneal vessels.

4. Trachoma-It is a chronic keratoconjunctivitis It is still one of the leading causes of preventable blindness in the world
Symptoms-
1 In the absence of secondary infection symptoms are minimal & include mild foreign body sensation in the eyes occasional lacrimation slight stickiness of the lids & scanty mucoid discharge
2 In the presence of secondary infection typical symptoms of acute mucopurulent conjunctivitis develop.

5. Spring catarrh- It is a recurrent bilateral interstitial self-limiting allergic inflammation of the conjunctiva having a periodic seasonal incidence
Symptoms-1 Spring catarrh is characterized by marked burning & itching sensation which is usually intolerable. Itching is more marked with palpebral form of disease.
2 Other associated symptoms include mild photophobia, lacrimation, stringy (ropy) discharge & heaviness of lids.

6. Phlyctenular conjunctivitis- It is a characteristic nodular affection occurring as an allergic response by the conjunctival and corneal epithelium to some endogenous allergens to which they gave become sensitized Phlyctenular conjunctivitis is of worldwide distribution However its incidence is higher in developing countries
Symptoms- In simple Phlyctenular conjunctivitis are few like mild discomfort in the eye irritation & reflex watering. However usually there is a associated mucopurulent conjunctivitis due to secondary bacterial infection.

7. Glaucoma- It is not a single disease process but a group of disorders in which intraocular pressure is raised above the tolerance limit of the affected eye resulting in damage to the optic nerve head & irreversible visual field defects.

8. Xerosis (Dry eyes)-Xerosis of the conjunctiva is a symptomatic condition in which conjunctiva becomes dry & lusterless
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