1. In the normal eye, the retina is shielded from much of the UV radiation by the filtering action of the cornea and the lens.

True

False

None of the above

Can't say

2. The transmission of the cornea (particularly for the shorter wavelengths) increases markedly with age.

True

False

None of the above

Can't say

3. Patients who work under conditions of good designed illumination usually report glare that interfaces with vision and produces discomfort.

True

False

None of the above

Can't say

4. Coated lens is tinted by depositing a thin metallic oxide on the surface of the lens.

True

False

None of the above

Can't say

5. The tear layer absorbs only a small amount of radiation.

True

False

None of the above

Can't say

6. The most common effect of ionizing radiation is the formation of cataracts.

True

False

None of the above

Can't say

7. IR radiation occupies slightly more than 7 octaves.

True

False

None of the above

Can't say

8. Antireflection coatings are a type of optical coating applied to the surface of lenses and other optical devices to reduce reflection.'

True

False

None of the above

Can't say

9. LTF stands for

Light Transfer Factor

Light Transmission Factor

Both and

None of the above

10. Which type of lenses also have a uniform density appearance because the coating is applied uniformly over the lens surface?

Coated

Uncoated

Both and

None of the above

11. A spectral transmittance curve shows the percentage of transmission for which type of the following spectrum and for portions of the UV and IR wavelengths?

Invisible spectrum

Visible spectrum

and

None of the above

12. Once the transmission of a material is known, the density may be found by use of the relationship

Density =loglO Opacity

Density =log20 Opacity

Opacity =loglO Density

Opacity =log20 Density

13. Discomfort glare occurs when the ratio between the level of illumination in the visual field and the background illumination exceeds a ratio of 3 to 1.

Highest

Lowest

Both and

None of the above

14. Which of the following are small, yellowish elevated concretions of bulbar conjunctiva, that have long been associated with continued exposure to solar radiation?

Pterygia

Pingueculae

Both and

None of the above

15. The radiation received by the retina is the radiation transmitted by the

Vitreous

Choroid

Sclera

None of the above

16. IRradiation occupies slightly more than

3 Octaves

7 Octaves

10 Octaves

5 Octaves

17. Visible spectrum occupies only

1 Octave

2 Octaves

3 Octaves

4 Octaves

18. CR-39 stands for Columbia Resin, version number

39

38

93

83

19. If all the wavelengths of light are equally absorbed, then which colour (neutral density) tint is produced?

Grey

Red

Green

Black

20. Type(s) ofAbsorptive Lens(es) is/are

Tinted plastic lenses

Photochromic lenses

Polarizing lenses

All of the above

21. Different absorptive substances may produce lenses of similar but the spectral transmission curves for the lenses differ.

Colour

Design

Base

Shape

22. Glare can be classified as

Veiling (disability) glare

Discomfort glare

Specular reflections glare

All of the above

23. Strongly coloured tints may affect

Colour vision

Visual field

Both and

None of the above

24. The hydrophobic layer is very comparable to a few molecules, and therefore does not interfere with the optics of the AR coating.

Thin

Thick

Dark

Light

25. UV radiation extends approximately from

100 to 200 nm

200 to 380 nm

300 to 400 nm

400 to 500 nm

26. People employed in occupations such as nuclear physics, radiology, uranium mining and engineering are at risk from .

Ionizing

Non-ionizing

Both and

None of the above

27. Exposure to radiation bordering on the visible spectrum can cause the sensation of vision.

True

False

None of the above

Can't say

28. Factors affecting transmittance of photochromic glass are

Intensity of incident radiation

Wavelength of incident radiation

Temperature of glass

All of the above

29. Which of the following are growths of vascular and connective tissue into the epithelium of the bulbar conjunctiva and the cornea?

Pterygia

Pingueculae

Both and(2)

None of the above

30. Which of the following lenses cannot be surface coated by evaporation because they would be deformed by the high temperature required?

Tinted plastic lenses

Tinted glass lenses

Both and

None of the above