American Board of Opticianry (ABO) Practice Test 2026 – The All-in-One Guide to Master the American Board of Opticianry Exam!

Plastic is generally hypoallergenic, so option C is not the most likely cause of allergic reactions within a metal frame.

Both titanium and aluminum are considered bio-compatible and are often used in medical implants, making them unlikely to cause allergic reactions.

On the other hand, nickel is a common allergen and is often found in metal frames, making it the most likely material to cause allergic reactions among the given options.