Don’t freak out. Fitting and managing keratoconic patients needn’t be as scary as you think.
One of the things that generates the most requests for help from colleagues is the fitting and management of keratoconus (KC). For various reasons this interesting condition puts the fear of God into many practitioners. It seems people simply freak out when faced with a keratoconic. Unlike their normal rational approach to problem solving other pathologies, and the therapeutic challenges they face daily, they seem to want to run for the hills.
Maybe it’s the stigma that surrounds keratoconus or the perception that keratoconics can be a little strange personality wise?
It’s also due to the fact that many recent graduates have not dealt with enough (if any) cases of keratoconus before being let loose on the public.
The first thing I do with these patients… is to explain exactly what keratoconus is
It seems many overcomplicate the situation and dive in with scleral or asymmetric RGP designs. For a significant number of sufferers, simpler spectacles or soft lens designs can work wonders.
Classifying the case according to a few basic principles can make the processes a lot less stressful. In doing so excellent outcomes can be obtained, leading to happier patients who become great referral sources.
Suffering from Kittycaronas
I receive email requests from colleagues and have many discussions at conferences and via online forums regarding such cases. Mostly I can help the practitioner – via remote control and telemedicine – to decide on the best strategy and lens design. The feedback is usually positive. In some cases however, the keratoconus is extreme and referral to a specialist contact lens practitioner is the best way forward.
What I’ve often gleaned during the initial consults with my own keratoconus patients is quite revealing. In many of these cases, the patient has been through the mill. Most were referred by existing patients, or the patient found me via an online search.
They present with a long story that smacks of frustration. Although some are well informed about their condition, others have no clue. Their former practitioner/s have obviously done a poor job of explaining and managing the condition. They tell me they are suffering from ‘kittycaronas’, ‘stigmata’ or ‘lazy eye’.
Pulling Their Hair Out
They cite a litany of failed attempts at RGP or scleral lenses and swear they never want another lens in their eye. At times, motivated to see and function as ‘normally’ as possible, they have stuck it out, often without follow-up. In many of these cases I’ve seen over the years, flat fitting corneal RGPs have caused apical abrasions, with resultant pain, photophobia and scarring.
In other cases, tight fitting scleral lenses have led to marked neovascularisation.
Fortunately such complications are few and far between, and there are, of course, many patients who have not suffered any harm but have simply grown tired of repeat visits to a variety of practitioners. Those I’ve seen have shown me a bag of spectacles, which they claimed were useless. Or they’ve pulled out boxes and bottles of soft lenses that they stated were ‘no good’. They have reported distortion, ‘ghosting’ or being able to see as well without their glasses. Some were not even diagnosed as suffering from KC – these were often mild, subclinical cases of forme fruste keratoconus (FFKC), which had not been detected thanks to a rather cursory examination and autorefraction. If performed, a decent retinoscopy, along with topography, would have made the diagnosis. Had the practitioner done the pretesting themselves, with careful observation they may have noted mild distortion of the mires during autokeratometry or noted an autorefraction that did not come close to the final spectacle Rx. Other things that should ring alarm bells and point the practitioner in the right direction are low IOPs, resulting from sub-500 micron corneas, which a four-in-one instrument or other forms of pachometry should detect.
Three Simple Steps
First Things First
The first thing I do with these patients, after the initial case history and a battery of diagnostic tests, is to explain exactly what keratoconus is. I do this by showing them their topographic maps, corneal thickness, images and diagrams. I go on to discuss the issues surrounding eye rubbing and the need to manage their atopia and allergies, where necessary.
I then present their options. If they are suffering from FFKC and a decent refraction reveals the ability to get satisfactory vision then it’s well and good.
The target acuity is usually 6/7.5 but some patients will be 6/happy by obtaining 6/12 legal driving vision. In many cases 6/6 is possible with these milder cases. Many, once they understand, are happy with spectacles or soft lenses. The latest generation si-hy dailies sometimes provide superior vision to older designs and materials, while the latest soft torics with extended ranges often provide outstanding results.
For more advanced cases, where spectacles are useless – with distorted best-corrected visual acuity well below 6/12 – I explain that if we are lucky we will obtain acceptable vision with soft lenses but most likely a corneal RGP is necessary. For those that are significantly intolerant, a piggyback system can work wonders.
It’s now down to trial fitting. Having a decent range of RGP and soft toric trial lenses will often provide the answers in minutes. I use the closest soft toric and over-refract then order in an extended-range soft toric that will often do the trick. If you don’t have the luxury of such broad fitting sets then empirically order the Rx needed, using the ocular Rx and assuming zero rotation.
A custom designed RGP or proprietary design is ordered when needed.
Lenses are dispensed, the patient sent out for a few hours trial and then carefully instructed on lens handling and proper cleaning and disinfection using the most innocuous, preservative free system possible. Proper aftercare, fine tuning the lenses and tailoring allergy and ocular surface management, will also help attain success.
A Case in Point
One such case, per the kind feedback of a colleague in my former practice in Auckland, is a good example of what’s possible. He recently sent me the following email.
‘I saw your patient XXXX on Saturday. You may remember he was a grafted keratoconic that you fitted with one Biofinity XR and one normal Biofinity toric. The XR toric needed minor tweaking after it was worn initially for two weeks. He now sees 6/6 in that eye which is amazing considering it’s a -5.75 cyl. He’s overjoyed with the clarity, comfort and the remarkable 3D vision he now attains which helps with his job. He has also gone to obtain a learner driver’s licence, so you and Prof. McGhee have restored his life…’
I remember this case well. The patient had moved to Auckland from the South Island. I’d seen his wife who begged me to see what I could do for him. He was pretty much non-functional with around 6/60 vision. He’d suffered numerous failed attempts at RGP and scleral wear and was rather upset that optometrists and ophthalmologists had missed his apparent steroid induced cataract and glaucoma. His graft, followed by a toric IOL, helped set up a platform from which I could work some more magic. Colleagues in Auckland regularly review and manage his glaucoma and keep an eye on his lenses and grafts.
A great outcome and happy ending, after years of struggle.
Keep it simple!