Pestana Chap 9 - Ophthalmology Flashcards
What is Ambylopia? What is the most common expression of this phenomenon? What will happen if this expression is not corrected early on? What else can cause this same problem?
1) Amblyopia is a vision impairment resulting from interference with the processing of images by the brain during the first 6 or 7 years of life
2) The child with strabismus. Faced with two overlapping images, the brain suppresses one of them
3) If the strabismus is not corrected early on, there will be permanent cortical blindness of the suppressed eye, even though the eye is perfectly normal
4) Should an obstacle impede vision in one eye during those early years (for instance, a congenital cataract), the same problem will develop
How is strabismus verified? Why should strabismus be surgically corrected with diagnosis?
1) Strabismus is verified by showing that the reflection from a light comes from different areas of the cornea in each eye
2) Strabismus should be surgically corrected when diagnosed to prevent the development of amblyopia
What happens when reliable parents state that a child did not have strabismus in the early years but develops it later in infancy? How is it corrected? Does a true strabismus resolve on its own?
1) The problem is an exaggerated convergence caused by refraction difficulties
2) In that case corrective glasses instantly resolve the problem
3) True strabismus does not resolve spontaneously
How should a white pupil in a baby be managed and why? Even if the white pupil is caused by a less lethal problem, why should it be attended to?
1) A white pupil in a baby is an ophthalmologic emergency, as it may be caused by a retinoblastoma
2) Even if the white pupil is caused by a less lethal problem, like a congenital cataract, it should be attended to in order to prevent ambylopia
Is glaucoma likely to be discovered by regular physicians? Which form of glaucoma should be recognized by all physicians who may encounter it and how does it present? What will physical exam reveal?
1) Glaucoma is a very common source of blindness, but because of its silent nature, it is unlikely to be discovered by regular physicians (or to be tested for in an exam)
2) Acute angle closure glaucoma shows up as very severe eye pain or frontal headache, typically starting in the evening when the pupils have been dilated for several hours (watching a double feature at the movies, or watching TV in a dark room). The patient may report seeing halos around lights
3) On physical exam the pupil is mid-dilated and does not react to light, the cornea is cloudy with a greenish hue, and the eye feels “hard as a rock”
What treatment is required for acute angle closure glaucoma? What treatment can be used in the meantime before required treatment?
1) Emergency treatment is required (ophthalmologists will drill a hole in the iris with a laser beam to provide a drainage route for the fluid that is trapped in the anterior chamber)
2) While waiting for ophthalmologist, administer systemic carbonic anhydrase inhibitors (such as Diamox) and apply topical beta-blockers and alpha-2-selective adrenergic agonists. Mannitol and pilocarpine may also be used
How does orbital cellulitis present and what is the key finding? Is there pus in the orbit? What scan and what procedure must be done?
1) It is an ophthalmologic emergency in which the eyelids are hot, tender, red, and swollen, and the patient is febrile - but the key finding when the eyelids are pried open is that the pupil is dilated and fixed, and the eye has very limited motion
2) There is pus in the orbit
3) Emergency CT scan and drainage have to be done
What do chemical burns of the eye require and when must it be started?
Chemical burns of the eye require massive irrigation, like their counterparts elsewhere in the body. Irrigation with plain water has to be started as soon as possible wherever the injury happened; it cannot wait until arrival at the hospital
Once a chemical eye burn has been pried open and washed under running water at the scene, what is the next step in management? What is to be done at the hospital? What must be done before the patient is discharged?
1) Transportation to the ER should be arranged
2) At the hospital, irrigation with saline is continued and corrosive particles are removed from hidden corners
3) Before the patient is sent home, pH is tested to assure that no harmful chemicals remain in the conjuctival sac
Are alkaline or acid burns worse?
Alkaline burns are worse than acid burns
How does retinal detachment present? What does the number of floaters indicate?
1) The patient reports seeing flashes of light and having “floaters” in the eye
2) The number of floaters gives a rough idea of the magnitude of the problem. The individual with one or two floaters may only have vitreous tugging at the retina, with little actual detachment. The person who describes dozens of floaters, or “a snow storm” within the eye, or a big dark cloud at the top of his visual field has a big horseshoe piece of retina pulled away and is at risk of ripping out the rest
What is the emergency intervention for retinal detachment?
Emergency intervention, with laser “spot welding,” will protect the remaining retina
How does embolic occlusion of the retinal artery present? What must be done within the first 30 minutes of presentation before arrival to the ER?
1) Embolic occlusion of the retinal artery is also an emergency, although little can be done about it. The patient (typically elderly) describes sudden loss of vision from one eye
2) In about 30 minutes the damage will be irreversible, but the standard recommendation is for the patient to breathe into a paper bag and have someone repeatedly press hard on the eye and release while he is in transit to the ER (the idea is to vasodilate and shake the clot into a more distal location, so that a smaller area is ischemic)
What newly diagnosed patients require ophthalmologic evaluation and why?
1) Newly diagnosed diabetics need ophthalmologic evaluation if they have type 2, because they may have had it for years before diagnosis was made. Retinal damage may have already occurred, and proper treatment may prevent its progression
2) Youngsters diagnosed with type 1 are about 20 years away from getting eye problems
