Fitting scleral contact lenses is “a challenging area of practice,” attendees at the Specialist Keratoconus Symposium were told earlier this month.
The event was hosted by Hertford Optometry and Contact Lens Practice at Hertford Castle on 10–12 April and discussed the expanding role of scleral contact lenses when managing keratoconus.
During his presentation, Beyond the limbus: too large for a corneal but not quite a scleral, optometrist, contact lens practitioner and event organiser, Ken Pullum, said that the high degree of unpredictability when working near the limbus makes fitting scleral contact lenses a challenging area.
He explained: “The main challenge with fitting lenses that are 13–15mm in diameter, for example, is that you are just beginning to encroach on the limbus but you do not have enough of a peripheral bandwidth on those lenses to give you scleral baring and corneal clearance because it is an in between size. I see it as a challenging area of practice because you are introducing a high degree of unpredictably when you go onto the limbus.”
“When practitioners are fitting mini-sclerals, which I call the just beyond the limbus lenses, they need to bear in mind that there is a significant impact on settling back because you’re fitting on a conjunctiva and not on the cornea,” Mr Pullum added.
Mr Pullum told OT that the three-day event, which has been running since the mid 1990s, was established in response to a lack of training for modern scleral contact lenses.
“It became apparent to me over the years that corneal lens theory is not taught very well, if at all, at university. For specialist contact lenses, as we’re doing here for keratoconus, there’s nothing in the syllabus, so the only other option is postgraduate education,” he shared.
Speakers included senior optometrist at Moorfields Eye Hospital, Aneel Suri, who presented on soft lenses for keratoconus, and optometrist and deputy head of optometry at the London hospital Dr Vijay Anand, who spoke about optometry’s involvement with corneal transplant at Moorfields Eye Hospital.
Consultant ophthalmic surgeon at Queen’s Hospital in Romford, Bita Manzouri, explored what surgical interventions are available for keratoconus patients.
Ms Manzouri looked at the types of transplant and insertion surgery options such as intracorneal stromal inserts. She highlighted that full thickness superficial transplants are the most common with 4000 taking place across 150 centres in 2017.
However, she noted that transplants should only be considered as a last option after other treatments have been explored and less invasive therapies have been trialled.
During the presentation, Ms Manzouri also shared what types of questions patients ask about surgery options including when they will be able to drive, how long the graft will last and how many follow up appointments are required.
The British Contact Lens Association’s Nick Howard then presented Hybrid contact lenses: We may be uneasy but the patients love them…why is this?
He highlighted the expansion of the hybrid market from 2005–2010 as they provide another option for patients.
Mr Howard shared that optometrists can find hybrid contact lenses difficult to fit with poor levels of oxygen transmissibility, but patients find them comfortable.
Insight into the corneal crosslinking service at Moorfields Eye Hospital was then shared by principal optometrist, Marcello Leucci, who detailed how the service provides an option to avoid contact lenses and grafts.
Mr Leucci said that there is an 18-week pathway to see and treat patients at the London hospital with patients monitored for six months after for progression then annually for four years.
He shared that keratoconus is not in the domain of ophthalmology at Moorfields and crosslinking has taken 95% of keratoconus patients out of the external disease clinic.
Speaking about corneal cross linking, Mr Leucci explained: “The risk to benefit ratio is favourable. Treatment is over 98% effective. The risks are incredibly low and the chance of deterioration if you do nothing is very high. It’s very easy to justify for the NHS and the patient.”
He added: “It’s taken a huge load off our external disease clinics, which are already overburdened, and it will have an effect on our contact lens service, which will need to fit fewer contact lenses than they have done in the past. We’re catching these patients so early now that they are wearing glasses rather than contact lenses.”
The next Specialist Keratoconus Symposium will be held at Hertford Castle on 9–11 October. For further information on how to register and receive the event programme, email Hertford Optometry and Contact Lens Practice.