Fitting contact lenses to sleep in Flashcards
What is meant by extended wear
- 7 days & 6 Nights
- Wearing lenses for short period of time but having period where take them out, clean them and sleep without then stop wearing them again
What is meant by continous wear
- 30 days and nights
- Put lens first of month and take them out end of month
What is meant by flexible wear
- Occasional sleeping
What is planned Overnight Wear
Continuous and EW
What is Sporadic Overnight Wear
- Occasional flexible sleeping in
Physiological Considerations of sleeping in lenses
- Aim high Dk/t to ensure no significant corneal swelling
- Aim for the same as normal corneal swelling overnight 4% i.e same amount of swelling as you would if no lens was there
- Holden & Mertz Criteria – 87 Dk/t
- Harvett & Bonanno – 125 Dk/t
- Need to achieve these levels to not have overnight corneal swelling - Corneal Integrity
- O2 levels important
Why dont you need to worry about Dk/t with newer silicon hydrogel lenses for daily wear
Cause amount of O2 provided exceeds the requirement for no corneal swelling for daily wear
Why is corneal integrity imporant in EW lenses
Px wearing lenses all day and night so don’t want cornea that is prone to abrasions
Contraindications of sleeping in lenses - which px’s would you not consider
- Monocular Patients – cause only have one functional eye, if increased risk of issues and if there was adverse event = reduction in vision that is their only eye so not worth taking that risk
- Previous issues with corneal oedema
- Evidence of current neovascularisation
- Patients prone to CLIPC – caused by mechanical issues or hypersensitivity issues and if that px wears the lens more continuously = create issue
- Diabetics – their cornea is slower to recover from abrasion to epithelium. - increase infection
- Evidence of poor compliance – Increased risk of infection
Which px’s would you consider for sleeping in lenses
- Patient Preference e.g sleep in them , not clean them, wear more often
- Therapeutic Lenses e.g entropian = lashes growing in towards eye rubbing against cornea cause abrasion, by wearing a contact lens lashes will brush against lens so not damage eye
- Very young children (Aphakes) – cause cant put lenses in so need to put them in permanently
- No facilities for disinfection
- Vocational requirements e.g. nhs
- Social Activites
What do you want in fitting of lens
- Adequate tear exchange
- Cause will have metabolic waste products produced = can be trapped underneath the lens = need to come out
Why is fitting of lens important in people who sleep in lenses - what fit should you look for
- During day scl move a lot and towards end of day lens dries out a bit = cause lens is slightly tighter compared to earlier on in day
- SO check what the fitting will be like at the end of the day/overnight
- Preference for loose fitting cause will go tighter end of day due to eye getting drier
-So if lens does dehydrate and become tighter, it wont cause issues of tear exchange = reduces risks
What are the main soft lenses used for sleeping in
- Bausch and Lomb pure vision
- Air optix night and day = 30 days without taking them out
- Biofinity – for a week – monthly lens 4x
- Acuve oasys – for a week 4x
Fitting approach for existing wearers for sleeping in lenses
- Consider starting with daily wear with the new lens over the first few weeks to get used to wearing of lenses and handling, comfort
- Examine the patient after the first night of sleeping in them – corneal staining, hyperemia
- Review again after a period of time of extended wear – approx. 2-4 weeks – no adverse reaction to lens being in continuous contact with eye
- Ideally review after at least a weeks worth of wear and towards the end of the day – see fit end of day – worst case situation
- More regular routine aftercares with a view to 6 months maximum – Balance of risk – not 12 months due to adverse effects
- Depends on what lens starting with
Fitting approach for new wearers for sleeping in lenses
- Similar approach to existing
- Develop successful daily wear first then sleepwear
- Have a history of compliance
- Follow similar approach for existing wearers
- Consider earlier recalls = 6 months or 3 months to make sure complaint
