As the take-up of silicone hydrogel lenses for overnight wear increases, we ask three optometrists with 30 years fitting experience between them, who run practices in Australia and New Zealand, to share what lessons they’ve learnt.
Today, silicone hydrogel lens materials continue to increase in popularity as a proportion of all lens fits. In fact, they currently represent approximately 58 per cent of all lenses fitted in Australia, and for Australian and New Zealand practitioners, roughly 10 per cent of all contact lenses prescribed are for overnight wear.
The three practitioners I spoke to – Ray Fortescue, Peter Stevenson and David Bradley – all agree that careful selection of candidates for overnight wear is important and is influenced by their perception of the candidate’s compliance with instructions for safe lens wear. Whilst overnight wear options are discussed with most new soft lens wearers, they feel that the patients who ask for them and who understand the concept are the most motivated and most likely to be compliant.
They say that patients contemplating laser surgery, those with a high prescription and those who need a bandage lens are possible candidates for the modality.
First time CL wearers need to be comfortable with lens removal and insertion techniques so a few weeks of daily wear performance is useful
Ray Fortescue
Ray Fortescue from Fortescue Optometrists in Ramsgate, Sydney, says his practice mirrors the trends reported in the literature – silicone hydrogel lenses are probably 60 per cent of his fits, with daily disposables being the other 40 per cent.
“When silicone hydrogel lenses were first launched about 50 per cent of my fits were for continuous wear. I still believe in them but they are not for everybody. Now overnight wear probably represents about 10 per cent of my contact lens fits, most of those are at least six nights extended wear but a high percentage are flexi-wear, just one or two nights per week.”
Peter Stevenson
Peter Stevenson from Stevenson Sangster and Matthews in Wellington, New Zealand, has a slightly higher percentage of silicone hydrogel lens fits and overnight wear in his practice as he has a long history of prescribing for this modality.
“Most contact lenses I fit are silicone hydrogel, probably 80 per cent, the balance would be daily disposables and rigid gas permeable lenses. Of these about 20 per cent would be continuous wear and most of these are established patients.”
David Bradley
David Bradley from Eyes on Edwards in Brisbane adds, “Previous wearers of hydrogels who wear them seven days a week and more than twelve hours a day are ideal for refitting. Some lifestyles and travel schedules benefit a lot from the option of overnight wear.”
Ray says that people who travel frequently or live a hectic lifestyle report a need for lenses suitable for flexi-wear or occasional overnight wear. “There are always times when the patient might come home from the pub tanked or are out camping so will sleep in their lenses.
“If patients are sleeping in their daily wear lenses or being non-compliant, practitioners can help them avoid complications by fitting them with silicone hydrogel materials approved for overnight wear.”
Non-compliant patients top the list of people to be excluded from overnight wear.
“The patient must demonstrate a good understanding of the instructions we have given them and the precautions they need to take to ensure safe wear,” says Ray.
All three practitioners check for ocular surface or general health issues that might preclude wear such as blepharitis, rosacea, dry eye and contact lens papillary conjunctivitis (CLPC). Good vision and good lens fit are a must and smoking is also considered a risk factor for overnight wear.
The Benefits
The benefit of overnight wear is the freedom the modality offers, says Ray, “The successful continuous wear patients really don’t need to do anything to their eyes, it is as if they have had surgically enhanced sight – they are almost able to forget they have an issue with their vision. The ones with the lenses just love them and won’t go anywhere else – they are very loyal and very happy with their vision.”
Peter agrees that his patients appreciate the lack of fuss and problems as well as the good vision they enjoy in all situations. He also notes how cost effective the option can be because there is very little solution cost.
David finds overnight wear advantageous for patients with particular occupations. “The reduced lens handling requirements of overnight wear can be an advantage for patients where hand washing is an issue, such as landscapers or gardeners where thoroughly cleaning the hands is difficult despite vigorous scrubbing.”
He also finds that overnight wear provides an advantage for patients with solution sensitivity or other allergies as the eye remains free of solution components or other contaminants from the hands. For patients with nocturnal lagophthalmus, the lenses provide a bandage to protect the cornea overnight.
Weighing It Up
It remains important to weigh up the benefits of overnight wear against the potential risks. All the practitioners interviewed discuss the pros and cons of different modes of contact lens wear with their patients before fitting.
Peter characterises the risk with this analogy “It is like carrying a full bowl of liquid – you can do it, but you have to be very careful.”
The practitioners also find comparing risk rates to be useful to keep things in perspective for prospective candidates. For Ray, extensive experience with the modality helps to inform the discussion, “In our practice, we are comfortable because no one has ever lost vision, which compared to LASIK, makes overnight wear of silicone hydrogel lenses a preferable option.”
While microbial keratitis is rare, it is the most serious complication associated with contact lens wear. Silicone hydrogel lenses have not reduced the risk rate but they may have improved the outcome of microbial keratitis when treated appropriately.1 Immediate treatment with fortified antibiotics can make a tremendous difference in determining the severity of the outcome.2,3 Ray adds, “We have become confident that although the patients are in a lot of pain, they will recover well if hit hard and early with appropriate treatment. None of our silicone hydrogel lens patients with microbial keratitis have ever experienced vision loss.”
Practitioner Tips
Educating the patient to be alert to any changes in their eyes and to be responsive to those changes is a key. Pain can be an important differential diagnosis for microbial keratitis versus contact lens peripheral ulcer.
Ray says: “We emphasise that any irritation is bad, and that the wearer should not attempt to work through it.”
David instructs his patients, “If in doubt, take them out!” and Peter used the following memory aid to prompt patients to self monitor carefully, “Feel right, look right (in the mirror) and see right. If not then contact your practitioner promptly.”
First Time Wearers
First time CL wearers need to be comfortable with lens removal and insertion techniques so a few weeks of daily wear performance is useful. For overnight wear, the schedule should be within the approval of the prescribed lens type and designed to meet the patient’s needs. An appointment or at least a follow up phone chat after the first night of sleeping in lenses helps to ensure patients are suitable and monitor compliance with instructions.
The usual aftercare schedule for these practitioners is one week, one month, three months and every six months thereafter. The key tips they offer for the after care visits include careful assessment of the palpebral conjunctiva for contact lens papillary conjunctivitis and monitoring for any changes in limbal redness compared to baseline. They take advantage of the various lens properties offered by the multiple brands on the market (water content, modulus, surface performance, parameter range) to optimise the lens fit and physiological response for each wearer.
Solution compatibility issues can occur with silicone hydrogel lenses and multipurpose solutions, even when the patient has used that solution before with other lens types. While most patients can comfortably use any solution, some multipurpose solutions have been reported as having a higher incidence of solution induced corneal staining (SICS) with silicone hydrogels.4,5
Sometimes the characteristic staining pattern will not be observed but the patient will report dryness, general intolerance and perhaps a bit of redness. Using peroxide is an ideal way to avoid SICS.
The experience shared by these practitioners demonstrates how silicone hydrogel lenses allow them to meet their customers’ needs by offering them the modality that suits their lifestyle, whether that be daily, flexi or extended overnight wear.
Dr. Victoria Evans PhD BOptom (Hons) is a freelance writer and consultant to the ophthalmic industry. She was previously Head of Clinical Research for the Institute for Eye Research, has worked in clinical practice in Sydney, in contact lens research at the CCLRU, and in tear film and dry eye research at CRCERT and Oxford University.
