Keratoconus guide for optometrists

Symptoms and risk factors

In the early stages keratoconus can present with symptoms similar to non-keratoconus patients with astigmatism or myopia. The patient may report frequent changes to prescription, glare, diplopia or distorted vision. On retinoscopy, there may be an abnormal scissoring reflex or “oil droplet” sign, both of which can be the first indication of keratoconus. The speed of progression and severity of the stages of keratoconus vary between patients and their eyes.

Keratoconus is much more prevalent in male patients and in the South Asian ethnic groups.

Diagnosis of keratoconus

Keratoconus diagnosis is best confirmed by corneal topography, not least as such baseline scans are then available for subsequent comparison. From the majority of optometry practices, in which corneal topography is unavailable, patients are usually referred to secondary care based on increasing astigmatism and possible abnormal retinoscopic reflexes.

If keratoconus is confirmed, the progression of the disease is checked typically at 4-6 months intervals. At Moorfields, if keratoconus is not confirmed, we reassure the patient and recommend six-monthly refraction testing. However, if the optometrist observes a subsequent decline in spectacle-corrected visual acuity, suggestive of irregular astigmatism, we recommend referring patient back to us for further evaluation, regardless of whether it occurs in 1-2 years or later.

Benefits of an early referral

Seeing patients with early-stage keratoconus in a hospital setting offers the advantage of obtaining the earliest feasible baseline corneal topography data which can be used for subsequent comparison. Even though the corneal changes caused by the condition usually take time to become more severe, it is in the patient’s best interest to be referred as soon as keratoconus is suspected.

It is also very valuable to receive from the referring optometrist the up-to-date refraction and a record of the best corrected visual acuity at the time of referral. This information can be particularly beneficial in cases where there is uncertainty regarding the visual significance of the disease progression.

What can patients expect at their hospital appointments?

At their first hospital appointment, patients can expect the consultant to take their family history as it is not uncommon to have other family members affected by the condition. A detailed medical history will also be taken identifying any associated health problems such as allergic diseases and other conditions.

To monitor the progression of keratoconus, vision and refraction tests as well as and corneal scans are usually performed and compared to the previous results at each hospital visit of the patient.

Rate of progression

The rate of progression in keratoconus varies significantly. In some patients, there is quite a rapid progression in both eyes, in others it can progress only in one eye and remain stable in the other eye, and in some cases the progression is slow or negligible in one or both eyes (even in young patients, as has recently been reported from the Keralink trial).

In significant number of cases across all ages, keratoconus can spontaneously stabilise in one or both eyes. And the condition usually stops progressing at around the age of 30. Accordingly, treatment such as cross-linking is only offered when significant progression is confirmed.

Seeing keratoconus patients at Moorfields and Moorfields Private

We have a wide range of expertise in assessment of keratoconus as well as contact lens fitting. We have one of the biggest contact lens facilities in Europe, which means we can offer patients a very good range of specialist lenses.

Our consultants are highly experienced in treatments like cross-linking and corneal transplantation, performed in advanced progressing keratoconus cases. We also treat keratoconus patients for associated disorders including allergic eye disease and cataract. And we train the next generation of ophthalmologists who will be looking after keratoconus patients in the future.