If you’re preparing for the United States Medical Licensing Examination® (USMLE®) Step 2 exam, you might want to know which questions are most often missed by test-prep takers. Check out this example from Kaplan Medical, and read an expert explanation of the answer. Also check out all posts in this series.
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A 66-year-old man who is a smoker and has diabetes is having his routine yearly ophthalmologic examination. He has been treated with an oral hypoglycemic agent for several years. The doctor dilates the pupils and in the left eye sees the beginning of an opacity that is cutting off visualization of part of the retina. The patient's visual acuity has not changed at this time.
What is the most appropriate step in management?
A. Follow his exam more frequently.
B. Perform laser therapy on the affected eye.
C. Perform ultrasonic fragmentation of the lens nucleus.
D. Prescribe heavy glasses.
E. Treat the affected eye with topical steroids.
The correct answer is A.
A cataract is an opacity of the lens and is usually bilateral. Cataracts may be congenital, traumatic or secondary to systemic disease such as diabetes mellitus, corticosteroid therapy or uveitis. The most common type is the senile cataract, occurring at least to some degree in most people over 60. Cigarette smoking increases the risk. A cataract may be seen in early stages through a dilated pupil with an ophthalmoscope or slit lamp. With a mature cataract, the retina is not visible, and the pupil appears white. The main criterion for surgery is functional visual impairment. In the case presented here, surgery is not indicated at this time, but the patient should be closely followed.
Choice B: Surgery preserves the posterior lens capsule with removal of the cataract, but it may opacify as well, in which case laser treatment may be required.
Choice C: The surgery is typically done with ultrasonic fragmentation of the lens nucleus, which allows the surgery to be performed through a small incision without the need for sutures.
Choice D: An intraocular lens is routinely inserted during surgery so that heavy cataract glasses are not needed.
Choice E: Topical steroids are not indicated.
- Cataract is an opacity of the crystalline lens. It causes a gradual loss of vision.
- Surgery is indicated when the cataract is severe enough to impair the patient's everyday life.
For more prep questions on USMLE Steps 1, 2 and 3, view other posts in this series.