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2011-09-23 11:31:31
eye ophthamology

Diseases and disorders of the eye
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  1. Adenovirus conjunctivus
    Viral infection of the conjunctiva. Causes redness of the eye and conjunctiva. Produces watery discharge. Monocular but usually spreads to the other eye within a few days. Often presents with palpable preauricular nodes & URI with or without sore throat or fever. Conjunctival follicles may be visible. Treatment is cool compresses & topical tears/decongestants. Antibiotic drops to prevent bacterial overgrowth may be useful
  2. Adies pupil
    Characterized by a tonically dilated pupil resulting from damage to the ciliary ganglion (postganglionic fibers of parasympathetic innervation of the eye). Often secondary to inflammatory viral or bacterial infections
  3. Allergic/toxic conjunctuvitis
    Swollen lids with watery discharge and red eye are typical. Cool compress & decongestants & topical antihistamines & mast cell inhibitors & corticosteroids may all be used as treatment
  4. Amaurosis fugax
    Interruption of blood flow to the retina results in transient monocular blindness (painless)
  5. Amblyopia
    "The loss of one eye's ability to see details (""lazy eye""). Occurs when the nerve pathway from one eye to the brain does not develop during childhood. If treatment occurs before age 7 then unilateral blindness can generally be avoided"
  6. Anisocoria
    Pupils are of unequal size. Brown-eyed people are less susceptible to pharmacalogic anisocoria than lighter-eyed people because the melanocytes present in dark-eyed people take up medication
  7. Aphakia
    No lens is present in the eye - refractive disorder
  8. Astigmatism
    The cornea or lens is curved more in one direction than the other - refractive disorder. Can be corrected with glasses or hard contacts but soft contacts can only correct for small astigmatisms
  9. Bacterial conjunctuvitis
    Usually bilateral. Most often caused by Staph & Strep. Causes red eye with pus - lids are often stuck together in the morning. Topical antibiotics & warm compresses can be used as treatment. Very basic & cheap antibiotics can be used at high concentrations because of the topical administration. Hyperpurulent discharge can be indicative of N. gonorrhea infection and may require systemic treatment
  10. Blindness
    Legal definition: best corrected vision 20/200 or worse in the better eye & visual field restriction of less than 20 degrees. Leading causes = diabetes; glaucoma; macular degeneration; cataracts
  11. Cataract
    Any visually significant opacity of the lens. Protein changes within the lens cause it to become cloudy. Many different types: congenital; cortical; nuclear; posterior subcapsular (associated with DM & steroid use). Can occur at any age but the most common cause is aging
  12. Chalazion
    Caused by blockage of a Melbonian glan leading to formation of a lipogranuloma
  13. CN III nerve palsy
    Results in double vision; ptosis; enlarged pupil that reacts poorly to light; difficulty moving the eye in the medial direction or vertically. May be caused by an aneurysm in the posterior communicating artery
  14. CN IV nerve palsy
    Results in upward deviation of the eye that increases when the patient looks down and to the opposite side. Patients complain of diplopia. May be accompanied by a compensatory head tilt (away from the affected side). May be precipitated by trauma which causes bilateral palsies
  15. CN VI nerve palsy
    Causes difficulty looking laterally (affects the lateral rectus). May be accompanied by a compensatory head turn on presentation. CN VI has the longest cranial course and is most affected by elevated intracranial pressure. CN VI also travels over the clivus and so may be affected by diseases affecting bone (such as metastases)
  16. Dacryoadenitis
    Inflammation of the lacrimal gland
  17. Dacryocystitis
    Infection of the lacrimal sac
  18. Dibetic retinopathy
    Caused by changes in the retinal vasculature due to hyperglycemia. Dot and blot hemorrhages with hard exudates (soft exudates later in progression) may be seen. Death of the pericytes that support capillary endothelial cells in the eye can cause microaneurysms to occur (which can be identified histologically with trypsin digest). This causes leakage of fluid & protein (diabetic macular edema - vision loss due to this cause can be reduced with a focal laser). Iscemia may occur due to formation of microthrombi and this leads to neovascularization (proliferative retinopathy). These new vessels are fragile and bleed easily. Clot formation can cuase retinal detachment
  19. Ectropion
    Outward turning of the lower lid. Common with advanced age. Surgery is indicated with excessive tearing or exposure keratitis or for cosmetic reasons
  20. Entropion
    Inward turning of the lower lid. Occurs occasionally in older people as a result of degeneration of the lid fascia. May follow extensive scarring of the conjunctiva and tarsus. Surgery is indicated if the lashes rub on the cornea and botulism toxin may allow for temporary correction
  21. Esotropia
    Cross-eyed. When the fixating eye is covered the deviated eye moves to center
  22. Exotropia
    Wall-eyed. When the fixating eye is covered the deviated eye moves to center
  23. Giant cell arteritis
    A primary vasculitis involving medium- and large-sized vessels. Affects branches of the external carotid artery (including the ophthalmic artery). Symptoms include headache; jaw claudication; visual abnormalities; & markedly elevated ESR. Ophthalmic manifestations may result from ischemia of vessels supplying the choroid; inner retina; optic nerve; or extra-ocular muscles. Dipolopia is often a presenting symptom. Generally manifests in patients over the age of 50
  24. Glaucoma
    A progressive optic neuropathy. Associated with elevated pressure but not defined by it. Involves loss of peripheral vision early on and later loss of central vision. Problem is primarily at the level of aqueous humor outflow. IOP buildup leads to death of axons which manifests with a large cup-to-disc ratio on opthamalogic exam. Open-angle glaucoma (2/3 of cases): trabecular meshwork looks opon anatomically but aqueous humor does not drain properly. Closed-angle glaucoma (1/3 of cases): trabecular meshwork is clearly blocked by the iris and causes rapid buildup of aqueous humor in the eye (serious & acute). Closed-angle glaucoma in particular may lead to an oculocardiac reflex which causes cardiac symptoms & nausea
  25. Herpes keratitis
    Herpes simplex 1 is the #1 cause of inflammatory blindness in the US. Dendritic pattern of corneal lesion is characteristic. May cause lesions near the eye that resemble impetigo. Resembles herpes zoster but herpes zoster causes lesions that do not cross the midline & are often preceded by Hutchinson's sign
  26. Horner's syndrome
    Loss of ocular sympathetic innervation causes miosis & ptosis & facial anhidrosis. May be secondary to vascular disease or trauma or tumor
  27. Hyperopia
    Far-sightedness - refractive disorder. The eye is slightly shorter than normal and so light focuses behind the retina instead of on the retina. Can be corrected with a convex lens
  28. Hypertensive retinopathy
    The severity & duration of systemic hypertension determine the extent to which it can damage the vasculature of the eye. AV nicking is characteristic and occurs when thickened arterioles cross low-pressure venules. Grades I-III generally cause hard & soft exudates but not hemorrhage (generally seen only in type IV)
  29. Hyphema
    Collection of red blood cells in the anterior chamber of the eye
  30. Hypopion
    Collection of white blood cells in the anterior chamber of the eye
  31. Internuclear ophthalmoplegia
    Caused by lesions in the medial longitudinal fasciculus. Results in a disconnection between the abducens nerve nuclei and the contralateral oculomotor nucleus. This leads to a disjointed gaze with impaired adduction and nystagmus in the affected eye (defined as the eye for which the oculomotor nucleus is impaired - contralateral to the affected abducens nerve nucleus). Most commonly caused by multiple sclerosis
  32. Lens changes in diabetes
    The lens takes up glucose and thus water and becomes shorter and fatter in diabetes. This can cause myopia to worsen or can actually help patients with hyperopia. Excess sugars can also be converted into sugar alcohols which precipitate and form white streaks that lead to cataracts
  33. Macular degeneration
    Degeneration of the macular retinal pigment epithelium causing gradual painless bilateral central visual loss in the elderly. 2 types: dry (non-exudative & characterized by extracellular deposits calle drusen) & wet (exudative). #1 cause of blindness in those >65 years of age. More common in females & light-eyed Caucasians. Neovascularization can cause bleeding. Smoking & UV light exposure (especially in light-colored irises) are huge risk factors
  34. Mydriasis
    Dilation of the pupil due to disease or trauma or the use of drugs
  35. Myopia
    Near-sightedness - refractive disorder. The eye is slightly longer than normal and so light focuses before the retina instead of on the retina. Can be corrected with a concave lens
  36. Optic neuropathy
    A disorder of the optic nerve. Characterized by diminished visual acuity & abnormal visual fields & relative afferent pupillary defect & abnormal optic disc appearance
  37. Orbital cellulitis
    Usually caused by infection of the paranasal sinuses. Results in redness & swelling & impaired painful motility with or without proptosis.
  38. Presbyopia
    Difficulty focusing on near objects due to a decreased ability of the eye to accommodate near images. May result from a loss of elasticity in the crystalline lens
  39. Refractive disorders
    Includes mypoia; hyperopia; aphakia; astigmatism; presbyopia.
  40. Strabismus
    Deviation in ocular alignment - may be in any direction. Generally involves a lack of coordination in the ocular muscles. Often presents around age 2-3 but may present later in life as a result of trauma or other causes
  41. Uveitis
    Intraocular inflammation. Usually immunologic but may be infective or neoplastic. May be anterior (inflammation of the iris or anterior chamber) or posterior (inflammation of the retina & choroid). May cause hypopion