General Practice Flashcards
7 cards from real ABO NOCE Basic Opticianry practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 General Practice flashcards as text
A lensometer power cross shows +2.00 at 180 and +4.00 at 090. The prescription in minus-cylinder form is:
Answer: +4.00 -2.00 x 090
In minus-cylinder form, the sphere equals the highest plus meridian (+4.00 at 090); cylinder = +2.00 − +4.00 = −2.00; axis = 090.
Pantoscopic tilt is the angle formed between the lens plane and:
Answer: The vertical plane
Pantoscopic tilt is measured from the vertical plane; standard tilt is 8–12° with the bottom of the lens closer to the face.
A patient complains of a 'swim' or 'sway' effect with new progressive lenses. The most likely cause is:
Answer: Peripheral distortion inherent in the progressive corridor design
Progressive lenses have unavoidable peripheral astigmatic distortion outside the central corridor, causing a swim sensation during adaptation.
According to ANSI Z80.1, the allowable axis tolerance for a 2.00 D cylinder power is:
Answer: ± 7°
ANSI Z80.1 specifies ±7° axis tolerance for cylinder powers between 1.25 D and 2.00 D.
A patient inadvertently receives lenses with base-in prism. This will most likely cause the patient to experience:
Answer: Eyestrain or diplopia as the eyes are forced to diverge more than normal
Base-in prism displaces images temporally (toward the apex), requiring the eyes to diverge; excess divergence demand causes eyestrain or diplopia.
Which lens style is most appropriate for a patient who works at a computer 8 hours daily and also needs reading correction?
Answer: Occupational (office) progressive lens
Occupational progressives are optimized for intermediate and near ranges, providing wider and more comfortable zones for computer and desk work.
Effective power is clinically important when converting between spectacle and contact lens prescriptions because:
Answer: Vertex distance changes alter the vergence power reaching the cornea
When vertex distance changes, the effective vergence at the cornea changes, requiring a power compensation for prescriptions above ±4.00 D.