Keratoconus (KC) is a chronic, non-inflammatory, progressive thinning of the cornea with subsequent protrusion and distortion of the surface. These corneal changes cause increasing irregular astigmatism which, in turn, results in reduced visual acuity with spectacles. Contact lenses (CLs) remain the first line management option for visual rehabilitation when spectacles no longer provide adequate visual function.

Patient Centred Approach

Whilst achieving a CL fit that improves acuity, is comfortable to wear and interferes minimally with corneal physiology is a clinical priority, management of the keratoconic patient requires a much deeper and broader understanding of the condition, the ways in which it affects each patient as an individual and the management options that are appropriate for each individual. That is to say it requires a patient centred approach.

A recent inquiry by the Royal College of GPs (UK)1 identified three core elements to providing patient centred care:

  • A whole person rather than a disease specific approach – considering the effect of the condition and treatment of the ‘whole person’ rather treating the medical problem in isolation.

  • Personalised and flexible care – understanding that care plans for individuals with the same condition necessarily differ to take into account each person’s needs and values.

  • Care that empowers patients – providing information such that the patient can understand the condition and the management options open to them so they can collaborate with the practitioner in making informed decisions regarding their care.

This article will consider why this approach is so important in the management of KC and how practitioners can achieve it using good communication skills.

Why does KC require special consideration?

KC is a chronic condition – often bilateral though frequently markedly asymmetric – which generally onsets around puberty and exhibits a variable degree of progression in to the third and fourth decades of life. This implies that those affected most by symptoms, diagnosis, initiation of management options and progression of the condition are of studying, working and child rearing age. As such it is easy to see how the manner in which the individual perceives and deals with the condition and its management could positively or negatively influence life choices. This has an impact not only on the long term future of the individual but also on public health. Let us consider the discussions relevant for the keratoconic patient.

What do keratoconic patients worry about?

Discussion 1 - Will it get worse?

Why is this a concern?

Patients are concerned as to how KC will affect their career and life choices, how rapidly and how far change may happen, and if there is anything they can do to stop it getting worse. Examples of patient concerns from the authors experience include: ‘will I always be able see well enough to …

  • complete my studies / exams?’

  • go to university?’

  • do my job?’

  • drive (and therefore get to work or place of study)?’

  • play sport?’

  • help my children with their homework?’

What information does the patient need?

The patient needs to be aware of the nature of the condition and its prognosis so that they have a realistic perspective of the future.

Key features to discuss include:

  • It is a bilateral but frequently and often markedly asymmetrical condition

  • Onset is typically in teenage years with variable degrees of progression through until the third or fourth decade of life when it appears to plateau. The CLEK study 2 showed that over seven years’ observation, 19% of patients lost 10 letters or more on high contrast acuity tests and 31% lost 10 letters or more on low contrast tests (see Table 1)

  • Complications include corneal scarring and corneal hydrops. The former is a known part of the disease process, the risk of which increases the younger the person is when diagnosed, the steeper the baseline corneal curvature and for those wearing CL. Corneal hydrops is an acute, painful rupture of Descemet’s membrane causing gross corneal swelling and a dramatic reduction in visual acuity (estimated incidence 1.64 per annum per 1000 diagnosed cases of KC)

  • Regular topographical monitoring is indicated to ensure that CL are adjusted for any change in corneal curvature thus minimising risk of insult to the cornea and to ensure timely referral for corneal crosslinking (CXL) where appropriate

  • CXL is a relatively new treatment aimed at minimising progression of the keratoconus but is not a cure. It involves the combination of ultraviolet light and riboflavin drops to induce crosslinking of the stromal collagen, thereby stiffening and strengthening the cornea

  • Visual rehabilitation is primarily with CLs but if there are intractable problems such as inadequate acuity or poor tolerance then surgical options may be considered (see discussions 3 and 4)

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Discussion 2 - What will I do if I can’t wear my CL anymore?

Why is this a concern?

Keratoconic patients are highly dependent on their CLs for visual acuity and they are concerned about how they would function in their daily lives should they not be able to wear their CLs in either the short or long term. The author has experienced cases where patients have expressed reticence to tell their employer and, perhaps more surprisingly, their partner about their condition due to fear of rejection or less favourable treatment because they would be unable to perform to the same level should they not be able to wear their CL.

What information does the patient need?

A discussion is required regarding the many CL options available, the management of CL wear to reduce the risk of long term non-tolerance and the surgical options (see discussion 4). The author has treated many patients who have been previously informed ‘this is the best that can be done’. Whilst this is undoubtedly true in some cases there have been many where all CL possibilities have not yet been exhausted. In some cases a step back is even required to look at the bigger picture (see case example 2). It can be very reassuring for patients to hear that other lens types are available should their current system cease to be satisfactory, even if this involves onward referral to a specialist practitioner. A summary of the advantages and disadvantages of various lens types is provided in Table 2. Above all it is important to match the CL outcome to the individual patient’s needs in terms of lifestyle, acuity and psychological requirements. It should also be remembered that the goal for one patient is not the same as for another despite a similar clinical picture.

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Standard soft toric lenses can be useful especially in mild/early disease stages. Speciality soft lenses represent a natural progression and are designed to optically correct the irregular cornea by the use of aspheric optics and / or modified lens thickness. Modern manufacturing techniques also allow customised peripheries to be incorporated facilitating improved stability on eye as well as aberration control features.

Corneal lenses have historically been the major refractive correction modality for KC. They create a fine liquid layer between the anterior corneal surface and the posterior lens surface that neutralises most corneal astigmatism and irregularity.

Rigid lenses larger than the corneal diameter, referred to as corneo-scleral, semi-scleral, mini-scleral or scleral lenses are designed to bear in varying degrees, depending on the design, on the conjunctiva thereby creating a corneal vault. This allows surfaces of greater irregularity to be corrected as the lens is not so reliant on the direct relationship with the cornea.

Discussion 3 - Is keratoconus inherited?

Why is this a concern?

Those affected by the condition are prior to or at prime child-bearing age at diagnosis. Therefore it is easy to see why, especially female sufferers, would be concerned about the genetic basis for KC and the risk of passing it on to their offspring.

What information do they need?

The aetiology of KC can be described in simple terms as having no gender predominance and what is, so far, best described as a multifactorial aetiology. A genetic basis is suspected but it is a complex inheritance pattern that is not yet fully understood. In addition, it appears environmental factors play an equally important role in the disease becoming manifest. KC has associations including eye rubbing, atopy and systemic conditions such as Down’s Syndrome and non-inflammatory connective tissue disorders.

Discussion 4 - Why can’t I just have a corneal graft?

When is a corneal transplant appropriate?

Corneal transplant is indicated for KC when CLs no longer provide adequate acuity, well fitting CLs are not tolerated or there is poor resolution of hydrops.

What is the success rate?

The patient must be clear that the aim of corneal transplant is to provide them with a clear cornea and it is important that this is not interpreted as though refractive correction is no longer required. Spectacles or contact lenses may still be required post- operatively but the best corrected visual acuity can be expected to be superior to the preoperative condition.

KC is the best indication for corneal transplant in terms of long-term survival as the procedure takes place on tissue with essentially normal metabolism. The 2012 report of the Australian Corneal Graft Registry3 shows a mean survival of over 18 years (95% survive five years then 89%, 77% and 46% at 10,15 and 20 years respectively). This implies that there certainly may be an advantage to delaying surgical intervention while a patient is managing well with contact lenses, especially as the survive rate of second and subsequent grafts is reported as lower than the first. In addition, the graft survival appears to be largely unaffected by recipient age.

What does the operation entail?

Key features to discuss include;

  • Performed under local or general anaesthetic.

  • Uncomplicated procedure may take about an hour and is usually done as a day case.

  • Frequent reviews in the first year and less so thereafter.

  • Minimum of six months of anti-rejection drops.

  • Complete suture removal not normally undertaken before 12 months post-operatively (although individual sutures may be removed as early as three months).

Which procedure is best?

In recent years deep anterior lamellar keratoplasty (DALK) has emerged as an alternative to the traditional PK (penetrating keratoplasty). The former retains host endothelium and Descemet’s membrane intact and therefore negates the risk of endothelial cell rejection, permits earlier tapering of steroids, reduces the risk of secondary glaucoma and increases the wound strength. PK is more suitable where the host has already been adversely affected by the KC and/or there is deep stromal scarring which would limit the visual acuity outcome with a lamellar graft.

From a CL perspective it is worth remembering that protecting the cornea for future transplant is an important part of the patient management as neovascularisation and other adverse effects of CL wear will increase the risk of rejection.

Discussion 5 – Everyday considerations

There are also some daily practical concerns that patients wearing CL for KC may worry about and that as practitioners we can try to alleviate.

  • Lost or broken lenses – it is important to the patient to have spare lenses available as the loss or breakage of a lens can effectively stop them from being able to work/study/function normally until a replacement is supplied

  • ‘Niggles’ – practitioners should take care to consider carefully any issues that are described when taking a history or during the consultation, such as variable acuity/comfort through the wearing time or lenses dislodging. Such complaints are common in the authors experience but are often dismissed by patients and practitioners alike as ‘normal.’ More than ever, many of these issues can be remedied using the vast array of specialty CL designs and extensive custom modifications, making a significant difference to the wearer’s life

  • Long wearing times – reducing the risks associated with CL over wear and therefore potentially the long term risk of CL non-tolerance, spectacles can be a useful option for part time wear at non-visually critical times, perhaps evenings or weekends. One must be sympathetic to the fact that although the high contrast acuity may be acceptable with spectacles in at least one eye the reduced binocularity due to asymmetry of the condition, combined with reduced low contrast acuity, increased higher order aberrations and spectacle blur can make spectacles only tolerable for small amounts of time.

Quality of Life

Kymes et al 4 reporting on data collected using the National Eye Institute Visual Function questionnaire suggest that the effect of KC on vision specific quality of life (QoL) is disproportionate to its low prevalence and clinical severity. This is particularly evident in the mental health category that describes levels of worry, frustration and embarrassment, all of which are understandable in light of the discussions above. In addition it appears that high contrast acuity underestimates the impact of KC on the vision related QoL and that the more advanced the condition, irrespective of best corrected acuity, the greater the perceived impact on QoL.

Example case 1:

case-1Diagnosis: moderate LE KC

Visit 13 re: LE corneal RGP CL

Max wearing time 4 hours per day VA 0.10 LogMAR

Spectacle acuity RE: 0.00LogMAR LE: 1.00LogMAR

Scleral lens LE: 0.20LogMAR but unable to tolerate

Impression:

At this visit it was established that the patient’s prime concern was the ability to wear her soft daily disposable CL in the right eye. She was unable to do this as she could not tolerate the left eye being completely unaided and the corneal RGP gave an inadequate wearing time.

She was, however, happy with her spectacles therefore any CL that gave equivalent or better LE acuity than this (but that she could wear all day to allow her to wear her RE soft CL) may be accepted.

Management:

LE: refitted with soft specialty lens giving VA 0.40 with all day wear. The patient can now comfortably wear her right CL.

Example case 2:

case-2Routine aftercare:

Diagnosis: bilateral KC, long term bilateral corneal RGP wearer

RE: reports excellent comfort and stable acuity

LE: reports variable comfort but ‘as good as it ever has been’

On further questioning:

LE: lens worn for a few hours then removed due to increasing discomfort. Eye left ‘recover’ for a few hours during the working day then lens reinserted for a few hours later in the day.

Impression:

Px is essentially monocular for at least part of the working day and some degree of discomfort is experienced up to the point of removal and also upon removal until the eye has settled sufficiently to warrant reinsertion.

Management:

LE: refitted with semi-scleral lens ‘the difference in comfort is truly astounding and I am able to wear the lens round the clock’.

Conclusion

CL practitioners need to see not just an eye that needs a contact lens but a person behind the eye who needs to be able to function at their required level.

A keratoconic is an individual with specific requirements, who needs to understand all the options available and to know that their practitioner understands how the condition affects their everyday life. They need to trust the practitioner responsible for their management and feel able to participate in their management decisions.

The management of KC in practice is so much more than fitting the CL and a patient centred care approach will differentiate a keratoconus practitioner from a CL fitter.

Jennifer McMahon is a specialist optometrist, Oxford Eye Hospital

References

  • Royal College of General Practitioners. Inquiry into patient centred care in the 21st century. (2015). Downloadable from www.rcgp.org.uk/policy/rcgp-policy-areas/inquiry-into-patient-centred-care-in-the-21st-century

  • Wagner H, Barr JT, Zadnik K. Collaborative longitudinal evaluation of keratoconus study. Contact Lens and Anterior Eye (2007), Sep 30(4), 223-232

  • William KA, Lowe MT, Keane MC, Jones VJ, Loh RSK, Coster DJ. The Australian Corneal Graft Registry 2012 Report. Downloadable from http://dspace.flinders.edu.au/xmlui/handle/2328/25859

  • Kymes SM, Walline JJ, Zadnik K, Sterling J, Gordon MO. Changes in the quality of life of people with keratoconus. American Journal of Ophthalmology (2008), Apr 145(4), 611-617