Modality of Wear

Daily Lenses

only worn during waking hours

Flexible lenses

Mixture of daily wear and occasional night-time wear

extended wear lenses

day and night-time wear up to a week with one night off for cleaning

continuous wear lenses

day and night-time wear up to a month

Planned wear

lenses licensed for overnight wear where patient plans to sleep in them

sporadic wear

lenses licensed for overnight wear but where there is occasional overnight wear, unplanned overnight wear or napping in lenses

Rigid lenses replacements

as need - can be 2 to 3 years

frequent replacement - regularly scheduled, usually 6/12 or 12/12

soft lenses replacement

conventional - usually specialist lenses (can be up to 1 year)

disposable - up to 1 month

daily disposable - every day

Why should contact lenses be replaced?

to reduce complications

simplify cleaning

loss of dimensional stability over time

deposits

improve comfort

why can frequent replacement reduce complications

complications often caused by CL spoilation

what factors influence CL spoilation

care and maintenance regimen

wearing schedule

tear chemistry and other personal factors e.g. makeup

other influences on CL life expectancy

thickness

handling ability

environment

daily disposable advantages

convenience, no cleaning

lower risk of infection

lower risk of mechanical complications

good for occasional wear (cost effective)

good for young patients

daily disposable disadvantages

limited range of Rx

cost if worn frequently

handling can be trickier

1,2 and 4 weekly advantages

cost efficient for FT wear

easier handling

wider range of Rx available

1,2 and 4 weekly disadvantages

cleaning regime

reduced comfort at end of lens lifespan

cost if lenses are often lost/damaged

SCL >1 month can be used for

3,6 or 12 months

Wearing SCL > 1 month can

increase chance of infection

SCL > 1 month are likely to need

specialised custom fit and protein removers

When would you used rigid lenses

high rx

irregular corneal curvature

ortho-k lenses

previous issues with SCLs

rigid lenses advantages

cost efficient

excellent quality of vision

complex Rx available

good tear exchange

modifications of lenses possible

does not cover entire corneal surface

various tints available

irregular corneas

rigid lenses disadvantages

adaptation time

foreign bodies

breaking and scratching

precise fitting required

risk of loss

patient requirments

safety

comfort

knowledge/education

convenience

full time wear

>4 days a week

part time wear

2-3 days a week

considerations for night wear

corneal status

risk factors

rx

tear film

lid integrity

environmental factors

individual characteristics

risks of night time wear

corneal oedema

loss of corneal sensitivity

lens adherence

inflammation and infection