Chapter 9 - Ophthalmology Flashcards
What is amblyopia?
Vision impairment resulting from interference with the processing of images by the brain during the first 6 or 7 years of life
What is the most common expression of amblyopia in a child?
Strabismus
If not corrected, what will happen to a child with amblyopia?
Faced with 2 overlapping images, the brain suppresses one of them. If not corrected early on, there will be permanent cortical blindness of the suppressed eye, even though the eye is perfectly normal.
How is strabismus verified?
By showing that the reflection from a light comes from different areas of the cornea in each eye
Management of strabismus?
Surgical correction when diagnosed to prevent the development of amblyopia
When reliable parents relate that a child did not have strabismus in the early years but developed it later in infancy, what is the problem and how is it addressed?
Exaggerated convergence caused by refraction difficulties
Corrective glasses instantly resolve the problem
Management of a white pupil in a baby (leukocoria)?
Opthalmologic emergency; may be caused by a retinoblastoma
Should be attended to even if it is just a congenital cataract to prevent amblyopia
Common source of blindness in adults?
Glaucoma
Because of its silent nature, glaucoma is unlikely to be discovered by regular physicians. One variant should be recognized by every physician who might encounter it - what is it and how does it present?
Acute angle closure glaucoma
Very severe eye pain or frontal headache, typically starting in the evening when the pupils have been dilated for several hours (watching TV in a dark room, etc.)
The patient, often a female of Asian extraction, may report seeing halos around lights.
Exam - pupil is mid-dilated and does not react to light. Cornea is cloudy with a greenish hue, and the eye feels “hard as a rock.”
Rx acute angle closure glaucoma?
Emergency treatment required - ophthalmologists drill a hole in the iris with a laser beam to provide a drainage route for the fluid trapped in the anterior chamber
While waiting, give systemic carbonic anhydrase inhibitors (Diamox) and apply topical beta-blockers and alpha-2-selective adrenergic agonists
Mannitol and pilocarpine may also be used
Presentation of orbital cellulitis?
Hot, tender, red, and swollen eyelids, febrile
Key finding - when eyelids are pried open, pupil is dilated and fixed, and the eye has very limited motion
Pus in the orbit
Dx and Rx orbital cellulitis?
Emergency CT scan
Ophthalmologic emergency
Manage chemical burns of the eye?
Massive irrigation with plain water started ASAP wherever the injury happened
Once the eye has been pried open and washed under running water for ~30 minutes, transportation to the ER should be arranged.
At the hospital, irrigation with saline is continued, corrosive particles are removed from hidden corners, and before the patient is sent home, pH is tested to assure that no harmful chemicals remain in the conjunctival sac.
Presentation of retinal detachment?
Flashes of light and “floaters”
Number of floaters gives a rough idea of the magnitude of the problem -> 1-2 floaters may indicate vitreous tugging at the retina, with little actual detachment vs. dozens of floaters (“snowstorm” within the eye) or a big dark cloud at the top of the visual field -> big horseshoe piece of the retina pulled away and at risk of ripping out the rest
Rx retinal detachment
Emergency intervention with laser “spot welding” to protect the remaining retina
