Contact Lens Optics — Flashcards

Flashcard 1: The total refractive power of schematic eye: _____ D

Answer: 58.64

Flashcard 2: Soft lenses are made up of _____

Answer: Hydroxyethyl methacrylate (HEMA)

Flashcard 3: Refractive power (dioptre) =  1/_____

Answer: Focal length in metres

Flashcard 4: Moderate myopia, when the error is _____D.

Answer: -3 to -6

Flashcard 5: The total refractive power of the human cornea is approximately: _____ D

Answer: 43

Extra: • Total refractive power of the eye (Reduced eye): 60 D • Corneal power: +43 D (approx. 2/3 of total power) • Lens power: +15 to +19 D (approx. 1/3 of total power) Note: In the 'Reduced Eye' model, the eye is simplified to a single refracting surface with a total power of 60 D. The value 43 D specifically refers to the cornea in a standard schematic eye.

Flashcard 6: The approximate percentage of aniseikonia in a person with monocular aphakia wearing a contact lens would be _____%.

Answer: 8

Flashcard 7: The following retinoscope is also called _____

Answer: Priestley Smith retinoscope

Flashcard 8: What is the name of the following test used for testing colour vision? _____

Answer: City university test

Flashcard 9: _____ is used to test color vision

Answer: Nagel’s anomaloscope

Flashcard 10: Stenopaeic slit can be used to determine the axis of the cylinder in _____.

Answer: astigmatism