wk4: CLM - Soft Contact Lenses Flashcards
What is the most popular modality of contact lenses?
soft contact lenses
Propose 5 reasons for the popularity of SCLs
comfort improved design public awareness increased availability silicone hydrogel materials
List 5 general benefits of SCLs
initial comfort and short adaption period Flexible CL wear Ease of fit Induce minimal corneal distortion Excellent on eye stability
List 3 optical benefits of SCLs
Large optical zone = minimal flare
Reduced aniseikonia compared with spectacles
Improved tolerance of anisometropic prescriptions
List 5 lifestyle considerations of SCLs
Ease of replacement Low cost per lens Ideal for active lifestyles Low risk of FB/debris entrapment Cosmetic lenses
List 6 limitations of SCLs
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
Define “conventional” soft lenses
soft lenses with replacement interval >6 months (usually 6-12 months)
List 2 benefits of “conventional” soft lenses
Custom fitted: wide range of designs available
Cheaper lens cost overall per year compared to disposables
What time is it?
Pizza time
List 5 limitations of “conventional” soft lenses
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
How does oxygen permeability relate to adverse responses?
Lower oxygen permeability = higher risk of adverse response
Why is regular lens replacement important? Provide 4 reasons
Minimise effects of lens deterioration + deposition
Assist with compliance
Regular checks of ocular health
Detect changes in refraction or vision
List 8 advantages of disposable SCLs
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)
List 3 potential disadvantages of disposable SCLs
Most parameters available BUT some are not
Lenses may sometimes rip in their packets
Occasional px perception of higher cost or attitudes to disposability
Which SCL modality is generally not used that much anymore?
2-weekly
List 4 advantages of DAILY disposables
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
How safe are daily disposables= (DD)? (2)
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
List 5 potential disadvntages of daily disposables
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
How does the comfort of 2 weekly SCLs compare to monthly?
Fewer dryness symptoms and end of day discomfort
True/False: patients typically wear CLs a few days longer than their scheduled replacement times
True
What can optometrists do to encourage patient compliance with CL replacement schedules? (8)
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
What is the density of a handling tint? Does it have a cosmetic effect on eye colour?
usually 10%. Doesn’t have any cosmetic effect on eye colour
T/F: handling tints are standard on many of the disposable lenses
True
What 4 categories of tints can CLs come with?
Handling tint
Enhancement tint
Opaque tint
UV blocking
What are enhancement tints use for
modify apparent iris colour for lightly coloured eyes (so makes them darker)
What are opaque tints used for?
change iris colour
How much UV is absorbed by UV blocking lenses?
absorbs an average of 90% of UV
