Optician ABO Exam Questions & Answers 2026 (1–10)

Question 1

Which frame material is known for being the lightest commonly used in ophthalmic frames?

TheoryPractice · Accepted Answer

Titanium. Titanium is one of the lightest metals used in ophthalmic frames, offering an excellent strength-to-weight ratio. This makes it ideal for patients sensitive to heavy eyewear.

Question 2

Zyl (cellulose acetate) frames are best adjusted using which method?

TheoryPractice · Accepted Answer

Warm air or salt pan heating. Zyl frames must be heated before adjustment to prevent cracking or breaking. A warm-air frame heater or salt pan softens the material so it can be bent without damage.

Question 3

A patient with a nickel allergy should be steered away from which frame material?

TheoryPractice · Accepted Answer

Monel. Monel is a nickel-copper alloy and contains significant nickel content, making it unsuitable for patients with nickel sensitivity. Titanium and beta-titanium are nickel-free alternatives.

Question 4

Which frame material is most commonly used for rimless and semi-rimless mountings because of its high tensile strength?

TheoryPractice · Accepted Answer

Titanium. Titanium's high tensile strength allows it to withstand the stresses of drill-mount and rimless designs without cracking around the lens holes. It is the dominant metal for rimless mountings.

Question 5

Optyl is a proprietary epoxy resin frame material. What is its primary advantage over standard cellulose acetate?

TheoryPractice · Accepted Answer

It has shape-memory and returns to its original form when reheated. Optyl's cross-linked epoxy structure gives it thermal shape-memory: when reheated it returns to the factory shape. This is a key adjustment consideration — overcorrection can be undone simply by reheating.

Question 6

In the boxing system, what does the 'A measurement' represent?

TheoryPractice · Accepted Answer

The horizontal width of the lens opening. The A measurement (also called the eye size) is the horizontal width of the lens opening measured in the boxing system. It is one of the three key frame measurements (A, B, DBL).

Question 7

The distance between lenses (DBL) is measured from which points?

TheoryPractice · Accepted Answer

Nearest inner edges of each lens opening. The DBL (distance between lenses) is measured from the nearest inner edge of one lens opening to the nearest inner edge of the other lens opening. It defines the bridge span.

Question 8

A frame has an A measurement of 52 mm, a DBL of 18 mm, and a temple length of 140 mm. What is the total frame width (A + DBL + A)?

TheoryPractice · Accepted Answer

122 mm. Total frame width = A + DBL + A = 52 + 18 + 52 = 122 mm. This represents the span from the outermost edge of one lens opening to the outermost edge of the other.

Question 9

The B measurement in the boxing system refers to:

TheoryPractice · Accepted Answer

The vertical height of the lens opening. The B measurement is the vertical height of the lens opening, measured in the boxing system from the top to the bottom of the lens shape. It is important for determining segment height in bifocal prescriptions.

Question 10

A frame's effective diameter (ED) is 58 mm and the patient's PD is 62 mm. The frame has a DBL of 16 mm and an A measurement of 52 mm. What is the minimum uncut blank size needed?

TheoryPractice · Accepted Answer

64 mm. Minimum blank = ED + 2 × decentration. Decentration per eye = (A + DBL)/2 − PD/2 = (52+16)/2 − 62/2 = 34 − 31 = 3 mm inward. Minimum blank = 58 + 2(3) = 64 mm.

Optician ABO Exam Questions & Answers 2026 (1–10)

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