Spectacle Dispensing and Fitting Questions and Answers 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 Spectacle Dispensing and Fitting Questions and Answers flashcards as text
A patient returns complaining of headaches only when using their new progressive lenses for near work. The most likely cause is:
Answer: The reading zone is not being accessed due to incorrect fitting height
If the progressive fitting height is too low, the patient cannot comfortably access the near zone, causing them to strain through an intermediate corridor region.
The term 'effective diameter' of a spectacle lens refers to:
Answer: The smallest circle centered on the optical center that will encompass the entire frame shape
Effective diameter is the diameter of the smallest circle centered on the optical center that contains the entire edged lens shape, used to determine the minimum blank size needed.
When fitting a child with spectacles, which consideration is MOST critical compared to fitting an adult?
Answer: Proper pupillary distance and fitting height due to rapid facial growth
Children's faces grow rapidly, so PD and fitting height must be accurate and the frame must be appropriately sized for their current facial dimensions.
A plano lens fitted 14 mm in front of the eye has an effective power at the cornea of:
Answer: Plano (0.00 D)
A plano (zero power) lens has no vergence-altering effect regardless of vertex distance — it transmits light without convergence or divergence.
Which of the following frame materials is MOST resistant to corrosion and is commonly used for patients with metal allergies?
Answer: Titanium
Titanium is highly corrosion-resistant and hypoallergenic, making it the preferred choice for patients with nickel or metal allergies.
A patient's prescription reads OD -3.50 -1.25 x 090. The principal meridians of power are:
Answer: -3.50 D at 090 and -4.75 D at 180
The sphere power (-3.50) acts at the axis meridian (090) and the combined sphere+cylinder power (-3.50 + -1.25 = -4.75) acts 90° away at 180.
An interpupillary distance of 64 mm is measured on a patient, but the selected frame has a frame PD of 72 mm. The required decentration per lens is:
Answer: 8 mm total, 4 mm per lens inward
The difference of 8 mm (72 - 64) must be split equally, requiring 4 mm of inward decentration per lens to align optical centers with the pupils.