Keratoconus: specialist contact lenses in Stockport

What is keratoconus?

Keratoconus is a condition of the cornea, the clear window at the front of the eye. The cornea becomes thinner and weaker than it should be, and the normal pressure inside the eye pushes it outwards into a cone shape. The cornea does most of the eye’s focusing, so this change distorts the image reaching the back of the eye.

Glasses correct a regular curve. They cannot correct an irregular one. That is why keratoconus vision stays blurred, ghosted or doubled even with a brand new prescription, and why people are often told they have astigmatism that keeps changing before anyone names the condition.

It usually starts in the teens or early twenties and can begin as young as nine. In most people it progresses for around ten years and then settles, although the pattern varies. Both eyes are usually affected, often to different degrees.

Signs to look out for

• Vision that keeps changing, with new glasses that never quite work
• Ghosting, doubling or several faint copies of what you are looking at
• Glare and haloes around lights, especially when driving at night
• Astigmatism that rises at each eye test
• Itchy eyes and a strong urge to rub them

Rubbing matters. Many people with keratoconus also have allergies or dry eyes, and hard rubbing is thought to make the cornea weaker still. If your eyes itch, use a cold compress or press gently without rubbing, and tell us so we can treat the itch.

Types of keratoconus

Where the cornea is thinnest decides how you see. A central cone sits in front of the pupil and blurs vision early, even in a mild case. A low cone, or pellucid marginal degeneration, sits near the bottom edge of the cornea; glasses may work surprisingly well, but ghosting is often worse. Keratoglobus is a rarer, more general thinning across the whole cornea. Our topographer maps all of these, and the map tells us which lens design to reach for first.

How we assess it

Corneal topography maps the front surface of the cornea point by point and shows the cone’s position, height and steepness. OCT of the front of the eye measures corneal thickness and shows the lens sitting on the eye in cross-section. We repeat both at each review, so we can see whether the cornea is stable or still changing and act early if it is not.

Your options

Contact lenses

A contact lens creates a new, smooth optical surface in front of the irregular cornea. The layer of tears trapped between the lens and the eye fills in the peaks and troughs, and light can focus properly again. Which lens works best depends on the cone, your prescription, your tear film and your day.

• Miniscleral lenses are our first choice for most moderate and advanced cones. They vault over the whole cornea and rest on the white of the eye, so they are stable, comfortable and never touch the cone itself. Time XL is one of the designs we fit.
• RGP corneal lenses such as Rose K2 are small rigid lenses designed specifically for keratoconus. They give sharp vision and are easy to handle. Comfort takes a little adaptation.
• Hybrid lenses combine a rigid centre with a soft skirt: rigid-lens clarity with soft-lens comfort and stability.
• Specialist soft lenses such as KeraSoft can work well for early or low cones, and for people who cannot tolerate rigid lenses.
• Piggyback fitting places a rigid lens on top of a soft one when comfort is the sticking point.

Ordinary disposable soft lenses can still be fine in early cases, and if you see well in them there is no need to change. Rigid lenses do not slow keratoconus down, whatever you may have read; they correct vision while they are worn and the cornea returns to its own shape when they are out.

Corneal cross-linking

Cross-linking (CXL) is a hospital procedure that strengthens the cornea with riboflavin drops and ultraviolet light. It is the only treatment shown to halt or slow the progression of keratoconus in most people, which is why we watch topography closely in younger patients and refer promptly through the NHS when the cornea is still changing. CXL stabilises the eye; it does not restore the original shape, so most people still need contact lenses afterwards. We fit them once the eye has settled.

Other surgery

Corneal ring segments, implantable lenses and, in advanced cases, a corneal transplant are options your hospital team may discuss with you. We work alongside the hospital and fit lenses after surgery when they are needed, which is often.

What happens at a keratoconus consultation

1. We take a full history, including any hospital care, and measure your vision with and without your current correction.
2. We map both corneas with topography and scan them with OCT.
3. We place trial lenses on the eye and check the fit and the vision with each design.
4. Custom lenses are ordered to your measurements, usually within a couple of weeks.
5. At collection we teach insertion, removal and care, and check the lenses on the eye.
6. Aftercare reviews follow, at first after a few weeks and then at regular intervals, with topography repeated each time.

Fees for the consultation, lenses and aftercare will be published here plainly. Some patients are entitled to NHS help with the cost of specialist lenses through a hospital contact lens service, and complex prescriptions may qualify for an NHS voucher. Ask us and we will explain what applies to you.

Consultation and lens fees: to be confirmed by the practice.