Hard and soft contact lenses have always had their own advocates. Hard lenses bring the visual acuity that astigmats and presbyopes struggle to get from some soft lenses while soft lenses bring the comfort levels RGP wearers dream of. Hybrid lenses bring both these elements together.
The hybrid contact lens is not new. The first versions of a lens with an RGP centre supported by a soft outer appeared in the 1980s but were dogged by bonding issues between the hard centre and the hydrogel skirt they were also considered difficult to fit. More recent innovations in technology and materials have meant that since the mid-noughties more robust lenses and repeatable results from hybrids have been a reality.
This has been further enhanced by the introduction of silicone hydrogel soft lens materials, hyper Dk/t hard contact lens materials and computer numerical controlled lathing which has brought increased levels of accuracy and speed.
Traditional candidates for hybrid lenses are patients at the more clinical end of the spectrum such as those with high cyls, kerataconus and astigmatic multifocal wearers. Today hybrids continue to offer the opportunity to fit those patients but also more mainstream patients offering them increased levels of comfort and vision potentially reducing drop outs.
Phil Thompson of SynergEyes says it has two product families catering for a range of patients. ‘SynergEyes have several ranges from the Generation 1 products for keratoconics and post graft corneas, still widely used by hospitals, to their newer Generation 2 high Dk RGP/Silicone Hydrogel skirted lenses. These cover regular corneal astigmats with the Duette and Duette Progressive, for astigmatic presbyopes, through to the Ultrahealth and Ultrahealth FC for irregular corneas.’
Ian Sexton, Professional Services Manager for specialist lenses at No 7 Contact Lenses points to the widening patient base for hybrids. ‘We have fitted a range of patients, keratoconics, post graft, high cyls and multifocal patients.’ So it’s not just medical issues, he says. ‘We are also finding hybrids are suitable for patients who are becoming intolerant to their standard GPs, if they are having issues we can fit them with a hybrid and get better comfort.’ No 7 is finding success fitting astigmatic patients with its Elements hybrid and its No Fit No Fee initiative.
Lens manufacturing
Phil Tansley, administration director Cantor and Nissel, says the patient need should drive fitting. It offers the Cantor Hybrid for medium to high refractive errors, high and irregular astigmatism, presbyopia, kerataconus, corneal irregularities and pellucid marginal degeneration. ‘You can use them for patients that want the benefit of an RGP but don’t really want to wear an RGP so you have got the best-of-both-worlds kind of effect.’ He agrees that hybrids aren’t just for keratoconics and tricky cyls. ‘Anyone really. It’s pretty well known that RGPs are going to give you a better acuity than a soft lens no matter what. Some people would rather wear that but don’t want to wear something on their cornea so they go for a hybrid where they have an RGP that’s lifted away and the soft skirt does the fitting side of things.’
Thompson says this is at the heart of the hybrid.’ They give the comfort of a modern soft lens with the stable vision of an RGP – no more problems of rotation of soft torics. For corneal astigmats, especially those with cyls over 1.50DC, the slight variances in rotation of soft lenses can make their vision very variable. This quite often leads to reduced wearing time or even dropout of lenses altogether, let alone the increased chair time cost for the ECP to try and resolve these issues. As a hybrid corrects the astigmatism in the same way as an RGP, using the tear lens, the vision is never variable. The added advantage of the hybrid over an RGP is the soft skirt. The patients have no edge sensation of the RGP and the skirt also helps to centre the lens, making better use of the aspheric optics. When you throw presbyopia into the mix, then these become a much easier option for both the ECP and patient as they are not fighting with rotating cyls mixed with a progressive prescription and never really being sure what is causing an issue when the patient struggles.’
‘The big thing about hybrids is that you get really good centration because it has the soft skirt that holds everything centrally,’ says Sexton. For multifocal and cyls at oblique angles that tends to work really well.’ Fitting has also become simpler. ‘You can fit them empirically just from corneal data or from an existing RGP fit. If they [the patient] are a current RGP wearer then all we need from a practitioner is the current lens design and power and then we just make it into a hybrid lens.’
Innovation has also made the hybrid a better option says Thompson who points to a range of new products from SynergEyes including a new centre distance progressive Duette lens with adds from +0.75D to +5.00D and a range of optic zones to complement the centre near progressive. ‘This gives ECP’s a much wider scope especially for the early presbyope who quite often prefers centre distance designs when available. An additional item, which we are just waiting for CE approval on, is Tangible Hydra-PEG treatment for the lenses. It has its FDA licence in The States and is routinely used there. It makes the surface of the lenses extremely lubricious giving even greater comfort and increased wearing times especially for those with slightly drier eyes. Watch this space,’ he says.
Insertion and removal training at No 7
There are also other technical innovations that have improved hybrids, says Sexton. ‘It’s the bonding process which has become much better. Emmanuel Veillard, the inventor of No 7’s Elements hybrid has developed a new polymerisation process to bind the hard and soft lens materials so it doesn’t separate like some of the old ones used to.’ This is a 100dk/t material with a silicone hydrogel skirt.
Optical designs have also changed, he adds ‘We are using a lot more aspheric designs for the RGP portion which gives a better fit, improves the comfort and helps the tear exchange because it conforms more closely to the corneal profile.’
Tansley agrees that technical innovation, materials and design have improved. ‘I would say from a lathing point of view with the Eyebrid material and the way they are able to cut makes it a lot easier as a manufacturer to make the lenses. We use state of the art lathes these days that are able to cut many different things that the old machinery couldn’t cut before. It’s a double hit really that we have better technology and better material. It’s more accurate and more flexible. ‘Our cnc machines go to the nearest micron, that’s how accurate they are.’
Modern hybrid design
If hybrids are now such a good option why aren’t more practitioners using them? Sadly some misconceptions still persist.
‘The two most common misconceptions we’ve come across from ECP’s are that they are complicated to fit and expensive,’ says Thompson.
Whilst it is a little more complicated to fit the Ultrahealth range to irregular corneas, the Duette range, in all its formats is empirically fitted – so the ECP just needs to provide the spec Rx, with vertex distance if applicable, HVID (Horizontal Visible Ins Diameter, and K readings. For the new CD Prog, pupil size is also required.’
‘I think the biggest misconception is that they are difficult to fit,’ says Sexton.’ They look at it as some kind of witchcraft but it really is very simple now. We don’t need anything other than Ks and RX to make a pair of lenses on a normal eye.’
Duette fitting, central thinning with lift at the junction
Tansley agrees that practitioners’ views may need to change. ‘I think most people would have said that they [ hybrids] are inconsistent and they break too easily. Trying to stick an RGP to a soft lens is difficult and then trying to hydrate a soft lens when it is stuck to an RGP is even more difficult. What we have found with the Eyebrid material (See Optician 01.09.17 P. 16) is that it offers a better resistance to pulling apart than previous materials. I find that not too many practitioners these days get involved outside of the disposable mode, they fit daily disposables and that’s it. I suppose they could be a little bit frightened off because they don’t know how it’s supposed to look, how it’s supposed to fit and maybe because of the breakage issue which they may have experienced before or heard of.’
He says Cantor and Nissel offers guidance through leaflets showing the kind of fluorescein pattern ECPs need to be looking for.’ There are clear benefits for patients and practices,’ he says, but practitioners still lack confidence. He says not only can hybrids solve wearers problems, thereby boosting loyalty, but it makes business sense too. ‘They could potentially make more money from it’.
Thompson says pricing will always be up to the ECP. ‘For most it seems to be working out at a similar price to quality daily disposable lenses (in the order of £45 per month) and therefore much less than some of the newer daily multifocal lenses. Many patients will have been fitted previously with soft toric lenses and been unhappy with the vision. The Duette range is empirically fitted so takes little time to use and as differentiation is a buzzword these days, offering a product that solves problems for patients who may have struggled with other means of correcting their vision can only help to raise the practice and the ECP’s profile.’
Removal technique
Sexton at No 7 agrees that practitioners should take a second look at hybrids. ‘The fitting process has become so much simpler and certainly at the training events that we have run there’s been a very wide range of practitioners from the ones who are experienced to the ones that are very new to it to and want to find out more.’
Of No 7’s Elements he says: ‘It’s a good lens to fit and it has a high success rate. The patients like the lens they get good stable vision and it’s a comfortable and from a business point of view it’s a profitable lens to fit.’
The added bonus is that it isn’t a lens you can easily buy on the web. ‘The lens that we supply at No7 isn’t made available to any internet suppliers so it’s not something that patients would be able to duplicate.’
‘Any patient who has an issue resolved by a practice will usually remain loyal to that ECP,’ says Thompson. All three suppliers use the lens on a six monthly replacement basis and say buying the lens online is not an option for most patients.
Sexton says Hybrid lenses can differentiate a practice and retain business. ‘Look at the patients where they have run out of options with GPs. The GP wearers who have got to the end of the line and don’t know where to go next—go to hybrid. Soft lens wearers with high cyls that aren’t achieving stability of vision –go to Hybrid. Similarly multifocal patient not getting clarity of vision – go to hybrid.’