wk4: CLM - Soft Contact Lenses

Question 1

What is the most popular modality of contact lenses?

Answer 1

soft contact lenses

Question 2

Propose 5 reasons for the popularity of SCLs

Answer 2

comfort
improved design
public awareness
increased availability
silicone hydrogel materials

Question 3

List 5 general benefits of SCLs

Answer 3

initial comfort and short adaption period
Flexible CL wear
Ease of fit
Induce minimal corneal distortion
Excellent on eye stability

Question 4

List 3 optical benefits of SCLs

Answer 4

Large optical zone = minimal flare
Reduced aniseikonia compared with spectacles
Improved tolerance of anisometropic prescriptions

Question 5

List 5 lifestyle considerations of SCLs

Answer 5

Ease of replacement
Low cost per lens
Ideal for active lifestyles
Low risk of FB/debris entrapment
Cosmetic lenses

Question 6

List 6 limitations of SCLs

Answer 6

Limited application for higher degrees of astig
May not suit irregular corneas
Difficulty verifying parameters
Higher incidence of corneal inflammatory and infective events
Limited durability
Prone to deposition and drying

Question 7

Define “conventional” soft lenses

Answer 7

soft lenses with replacement interval >6 months (usually 6-12 months)

Question 8

List 2 benefits of “conventional” soft lenses

Answer 8

Custom fitted: wide range of designs available

Cheaper lens cost overall per year compared to disposables

Question 9

What time is it?

Answer 9

Pizza time

Question 10

List 5 limitations of “conventional” soft lenses

Answer 10

Require more maintenance + enzyme protein removal
Higher rate adverse reactions (cf disposables)
Lower O2 permeability
Less convenient to patient (if lost or torn)
Lathe cut manufacturing is labour intense and more expensive

Question 11

How does oxygen permeability relate to adverse responses?

Answer 11

Lower oxygen permeability = higher risk of adverse response

Question 12

Why is regular lens replacement important? Provide 4 reasons

Answer 12

Minimise effects of lens deterioration + deposition
Assist with compliance
Regular checks of ocular health
Detect changes in refraction or vision

Question 13

List 8 advantages of disposable SCLs

Answer 13

Inventory maintained in practice
Wide range of parameters
Improved ocular health
Px convenience
Ideal for part time wearers
Specialty lenses only slightly more costly
Numerous features incl. as standard (ting, UV block, inversion indicator)
Enhanced compliance? (6/12 reviews before lenses are ordered)

Question 14

List 3 potential disadvantages of disposable SCLs

Answer 14

Most parameters available BUT some are not
Lenses may sometimes rip in their packets
Occasional px perception of higher cost or attitudes to disposability

Question 15

Which SCL modality is generally not used that much anymore?

Answer 15

2-weekly

Question 16

List 4 advantages of DAILY disposables

Answer 16

Reduced potential sources of contamination as no care system
Avoids costs/inconvenience of CL solutions
Minimal risk of physiological complications
Max comfort + vision b/c no accumulation of deposits

Question 17

How safe are daily disposables= (DD)? (2)

Answer 17

DD wearers = lowest incidence of non-severe keratitis of all types of SCLs BUT other studies have NOT found a lower risk of microbial keratitis compared with other types of soft daily wear lenses

but yeah overall pretty safe

Question 18

List 5 potential disadvntages of daily disposables

Answer 18

Cost (highest for any lens type for FT wear)
Less parameters compared to monthlies
Less choice for astig, presbyopia correction and coloured lenses
Often only one base curve (8.6 amirite ;))
Limited availability of silicone hydrogel materials

Question 19

How does the comfort of 2 weekly SCLs compare to monthly?

Answer 19

Fewer dryness symptoms and end of day discomfort

Question 20

True/False: patients typically wear CLs a few days longer than their scheduled replacement times

Answer 20

True

Question 21

What can optometrists do to encourage patient compliance with CL replacement schedules? (8)

Answer 21

Reinforce compliance at every visit
Use open questions to identify non-compliant patients
Explain comfort, ,vision + ocular health benefits of compliance
Track order patterns
Utilise direct shipments
Suggest 1st and 15th of month as replacement aids for 2wkly
Electronic reminder systems
Back up glasses

Question 22

What is the density of a handling tint? Does it have a cosmetic effect on eye colour?

Answer 22

usually 10%. Doesn’t have any cosmetic effect on eye colour

Question 23

T/F: handling tints are standard on many of the disposable lenses

Answer 23

True

Question 24

What 4 categories of tints can CLs come with?

Answer 24

Handling tint
Enhancement tint
Opaque tint
UV blocking

Question 25

What are enhancement tints use for

Answer 25

modify apparent iris colour for lightly coloured eyes (so makes them darker)

Question 26

What are opaque tints used for?

Answer 26

change iris colour

Question 27

How much UV is absorbed by UV blocking lenses?

Answer 27

absorbs an average of 90% of UV