Chapter 4- Dispensing part I (2)

Question 1

What are the different types of lens coating?

Answer 1

1- Hard coat

2- Tints

3- UV

4- MAR- multi anti- reflection coat

Question 2

What is a hard coat?

Answer 2

It is an abrasion resistant coating

Question 3

What is the advantage of the hard coat?

Answer 3

Reduces scratches

Question 4

What is the disadvantage of a hard coat?

Answer 4

Cost

Question 5

What is MAR?

Answer 5

It is a multi anti- reflection coat.

Question 6

What are the advantages of MAR?

Answer 6

1- Can help eyestrain and fatigue by reducing unwanted reflections/ glare

2- Good for night driving

Question 7

What are the disadvantages of MAR?

Answer 7

Cost and smudges can be seen more easily

Question 8

What are the advantages of tints?

Answer 8

Reduces squinting in bright light

Question 9

What are the disadvantages of tints?

Answer 9

1- Can change the colour of things

2- Can reduce v/a as less light is coming into eye

Question 10

What are the advantages of blue light?

Answer 10

Can be good for computer use

Question 11

What are the disadvantages of blue light?

Answer 11

Lenses can look quite blue which may not look nice

Question 12

What does UV lens coating do?

Answer 12

Blocks UV rays

Question 13

What are the advantages of UV lenses?

Answer 13

1- Protection from unwanted UV radiation

2- Reduces risk of cataracts

Question 14

What are the disadvantages of UV lens?

Answer 14

Can make lenses look yellow

Question 15

What is a photochromic lens coating?

Answer 15

A lens that adapts from light to dark and vice versa

Question 16

What are the advantages of photochromic lens coating?

Answer 16

Gives patient one pair of glasses

Question 17

What are the disadvantages of photochromic lens coating?

Answer 17

1- Don’t work in cars

2- Slow to change back

Question 18

What are the advantages of polarised lenses?

Answer 18

Reduces unwanted reflections/ glare on wet surfaces

Question 19

What are the disadvantages of polarised lenses?

Answer 19

Can stop you seeing digital screens if the screen is polarised in a certain way

Question 20

What is the 1/16 mm rule?

Answer 20

For every 1mm that your PD is different from the patient, you must add or subtract 1/16 mm. VERY RARELY USED

Question 21

How do you do monocular pupillary distance?

Answer 21

Measure left eye to the middle of the nose and then middle of nose to right eye.

Question 22

When would you measure monocular pupillary distance?

Answer 22

If one eye is closer to the nose than the other.

Question 23

What is the inter- pupillary distance?

Answer 23

Distance between the centre of the pupils.