CLM - Soft Contact Lenses - Week 4 Flashcards
Does Australia have a high or low proportion of RGP lens fits?
Lo
hat is the most popular modality of contact lenses world wide?
Soft
Do contact lenses have a short or long adaptation period?
Short
Do soft contact lenses induce corneal distortion?
Minimally
Do soft contact lenses cause spectacle blur?
Minimally
Do soft contact lenses have high or low on-eye stability?
High
Do soft contact lenses have a large or small optic zone? What does this mean for flare?
Large optic zone, giving minimal flare
Is aniseikonia larger or smaller with soft contact lenses compared to spectacles?
Reduced aniseikonia
Are anisometropic prescriptions more or less tolerated with soft contact lenses compared to spectacles?
Improved tolerance
Are soft contact lenses easy to replace?
yesd
Do soft contact lenses have a high or low risk of foreign body entrapment?
Low
Are soft contact lenses appropriate for high degrees of astigmatism?
Limited application
Are soft contact lenses suitable for irregular corneas like keratoconus or trauma?
May not be suitable
Compare the incidence of corneal inflammatory and infective events of soft contact lenses with RGP lenses.
Higher incidence
Are soft contact lenses durable?
Relatively low durability compared to RGP lenses
What deposits are soft contact lenses prone to (3)?
Protein
Mineral
Lipid
How often were conventional contact lenses replaced? What is the deadline? How long could they last?
Generally replaced in 6 month intervals
Should at least be replaced annually
Could last for 3+ years
How does the lens cost of conventional contact lenses compare with disposable soft contact lenses?
The lens itself is lower cost, but with care systems, it is more expensive
Do conventional contact lenses have a higher or lower overall rate of adverse reactions compared to disposable lenses?
Higher
Do conventional contact lenses have higher or lower oxygen permeability compared to soft contact lenses?
Lower
Are conventional contact lenses common?
No
List 4 reasons why regular lens replacements are important.
Minimise the effect of lens deterioration and deposition
Assists with compliance
Detect changes in refraction
What is the most common contact lens modality?
Disposable
List 4 advantages of disposable soft contact lenses.
Improved ocular health
Reduced deposits
Thinner lens profiles
Patient convenience
What is the benefit of maintaining an inventory of disposable soft contact lenses in practice?
Allows easy trial of the correct BVP
Do disposable soft contact lenses have a narrow or wide range of parameters?
Wide
List 4 disadvantages of disposable soft contact lenses.
Most parameters are available, but some are not
Lens may sometimes rip in their packets
Occasional patient perception of higher cost
Patient attitude towards disposability
What is the most common form of replacement schedules for disposable soft contact lenses?
Dailies (increasing trend)
List 4 advantages of a daily replacement schedule for soft contact lenses.
Reduced potential for contamination
No cost/inconvenience of storage/solution
Minimal risk of physiological complications
Maximum comfort and vision due to no accumulation of deposits
Which replacement schedule for soft contact lenses has the lowest incidence of non-severe keratitis?
Dailies
How do the replacement schedules for soft contact lenses compare for the risk of microbial keratitis?
Some studies have not found any lower risk among specific schedules (they had similar risks)
What is the general consensus on the replacement schedules for soft contact lenses?
Dailies have the least complications
Compare the cost of dailies to the other replacement schedules.
Dailies cost more
Compare the parameters of dailies to the other replacement schedules.
More limited parameters, including for astigmatism and presbyopia
What is the base curve of daily contact lenses like and why does this matter?
Often only have one base curve
Not good for steep or flat corneas
Are dryness symptoms more or less in 2 week contact lenses vs 4 week contact lenses?
Fewer
What generally happens to wearing comfort and vision quality with monthly contact lenses?
How do the most recent SiH contact lenses compare?
A general decrease in both
SiH lenses were found not to differ significantly between 2 week and monthly
List the following by compliance rate (highest to lowest):
Fortnightly
Monthly
Dailies
Dailies
Monthly
Fortnightly
List three primary reasons for replacement non-compliance.
Forgetting which day to replace
Save money
Running out of lenses (DD)
What is generally the handling tint density for soft contact lenses? Does it have any cosmetic effect on the eye?
10% density
No cosmetic effect on the eye
In what two refractive errors is handling tint especially recommended and why?
Hyperopes and presbyopes who have near focussing difficulties
Aside from handling tint, list three other useful tints for soft contact lenses.
Enhancement tint
Opaque tint
UV blocking
What are enhancement tints and over what diameter are they tinted?
Can modify the apparent iris colour
Tinted over a diameter equal to the HVID
Are enhancement tint colours additive?
Yes
What are opaque tints and what effect do they have on visual field sensitivity?
Changes iris colour and is opaque
Visual field sensitivity is slightly reduced (<1dB)
How does the comfort of lenses with an opaque tint compare to those without?
Slightly reduced comfort due to surface irregularties where the tint is
Give an example of a non-cosmetic use for opaque tinted soft contact lenses.
A blind eye with a damaged or irregular pupil or damaged iris
What percentage of UV light can UV blocking lenses absorb up to?
Up to 90%
