Question 80 of 100
(demo test)
Product Demo for COA Exam Questions
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A 70-year-old woman is delighted that she can now read the newspaper without her bifocals. She has needed bifocals for near work since age 45, and the change started about a year ago. Her distance vision has slowly become blurrier, and each yearly refraction has been more nearsighted than the last. What most likely explains her new reading vision?
The likely cause is the increasing density of her cataracts. A cataract is a clouding of the crystalline lens inside the eye. As the lens grows denser, it can also gain focusing power. Extra plus power makes the eye more nearsighted, which matches the steady myopic shift in her yearly refractions. A nearsighted eye sees near objects clearly without accommodation, so the reading add is no longer needed.
Two ideas explain the whole story. First, myopia means the cornea and lens have too much plus power for the length of the eye. Distant images land in front of the retina and look blurred, while near vision stays good. That is exactly her pattern: better reading, worse distance. Second, presbyopia is the slow loss of the lens's ability to change shape. It is a normal part of aging and it does not reverse, so her reading did not come back because focusing power returned. The clue that points to the lens is the drift toward more minus over time. A gradual myopic shift in an older adult should make you think about a denser lens rather than a new glasses problem.
Track the refraction over the years, not just today's number. A slow, steady myopic shift with dimmer distance vision points toward the crystalline lens. Once glasses no longer give good quality vision, the ophthalmologist discusses cataract surgery, in which an intraocular lens replaces the lost power. Connecting refractive change to lens change is part of the COA refraction content area.
Incorrect Answers
- A. A changing corneal shape shows up as new or shifting astigmatism, and it is usually driven by disease, surgery, or contact lens warpage. It does not explain a steady myopic drift with a cloudy view.
- B. Accommodation is lost, not regained, with age. Presbyopia is a normal aging change of the lens, so a 70-year-old does not start focusing up close again.
- D. Age-related macular degeneration damages the macula and reduces central and reading vision. It would make her newspaper harder to read, not easier.
Testing Pearls
- Myopia means too much plus power for the length of the eye, so distance blurs and near stays clear.
- A myopic eye focuses near targets without accommodating.
- Presbyopia is the progressive loss of accommodation from normal aging and does not improve.
- A yearly refraction drifting more minus in an older adult is a clue to a denser lens.
- After cataract removal, power is replaced most often with an intraocular lens.
References
- American Academy of Ophthalmology. Ophthalmic Medical Assisting: An Independent Study Course. Chapter 3, Abnormalities of the Eye.
- American Academy of Ophthalmology. Ophthalmic Medical Assisting: An Independent Study Course. Chapter 5, Optics and Refractive States of the Eye.
