Pathology of the Eye Flashcards
What are the types of refractive errors?
- Myopia (Nearsightedness)
- Hyperopia (Farsightedness)
- Astigmatism
Condition of the eye with too much focusing power; Cornea is excessively curved or eye is too long; As a result, light rays entering the eye are focused in front of the retina; Near objects, which require the most focusing power, can be seen clearly, but distant objects appear blurry
Myopia (nearsightedness)
- Most common refractive problem
Condition of the eye with too little focusing power; Due to insufficient curvature of the cornea or eye is too short; As a result, light rays entering the eye are focused behind the retina; Distant objects, requiring less focusing power, can be seen clearly, but near objects appear blurry
Hyperopia (farsightedness)
Eye is shaped like a football and is therefore asymmetrical; This results in multiple focal points inside the eye; Since some parts of the cornea have too much curvature, and other parts are too flat, objects both near and far appear blurry
Astigmatism
Like hyperopia but it is NOT a corneal problem; Lens of the eye loses its ability to focus, making it difficult to see objects up close; Lens elasticity is slowly lost as people age
Presbyopia
- usually around 45 yrs
What are the 3 components of normal tracking of the eye?
- Smooth pursuits -Allows the eyes to closely follow a moving object
- Saccades - Quick, simultaneous movements of both eyes in the same direction
- Nystagmus - Form of involuntary eye movement that is part of the vestibulo-ocular reflex (VOR); Alternating smooth pursuit in one direction and saccadic movement in the other direction
- Convergence - Simultaneous inward movement of both eyes toward each other
- Divergence- Simultaneous outward movement of both eyes away from each other
Lack of coordination between extra ocular muscles
Strabismus (eye misalignment)
- Exotropia - Eye moves outward
- Esotropia - Eye moves inward
“Lazy eye”; Caused by decreased vision in one eye; Brain starts to favor the “stronger” eye
Amblyopia
- type of strabismus
- typically patch stronger eye to force brain to use it
Children who have flat bridge of nose where it appears child has esotropia
psuedo esotropia
What eye conditions are often seen with down syndrome?
Increased incidence of:
- refractive errors
- strabismus,
- presbyopia
- nystagmus
- cataracts
What eye conditions are often seen with CP?
Strabismus
What eye conditions are often seen with hydrocephalus?
- Double vision
- reduced vision
- strabismus
- amblyopia
- “sunsetting sign”
- Increased CSF puts pressure on optic nerve
What eye conditions are often seen with fetal alcohol syndrome?
- Refractive errors
2. strabismus
In premature infants, the blood vessels may stop growing when they are born; When the vessels resume their growth, it can be in an abnormal fashion which causes damage to the retina; Usually resolves spontaneously
Retinopathy of Prematurity
- Normally seen in infants weighing less than 3lbs. 5oz.
- Normal blood vessels of the retina do not complete their growth until the end of a normal full term pregnancy;
Rare cancerous tumor of the retina; Generally affects children under age of 6; White pupil
Retinoblastoma
- 90% cure rate
- Treatment: Laser therapy, Chemotherapy, Radiation
