What are INTACS?

INTACS inserts are clear, thin prescription inserts placed in the periphery of the cornea during a brief procedure. INTACS inserts reshape the curvature of the cornea from within, without removing any corneal tissue.  INTACS inserts cannot be felt, are no more visible than a contact lens, and can be removed or replaced if needed, although this is uncommon.

INTACS inserts are microthin and hardly visible when placed in the cornea.

What conditions can be treated with INTACS?

INTACS inserts can be used to correct myopia (near sightedness) between -1.00 and -3.00 dioptres, with no more than 1.00 dioptre of astigmatism.  However, laser eye surgery has become a more popular method for the correction of refractive errors in healthy eyes.

On the other hand, INTACS inserts have found a valuable place in the treatment of Keratoconus and Corneal Ectasia.

Keratoconus

Keratoconus arises because of weakness in the layers of the cornea that leads to progressive thinning.  Normal pressure within the eye causes the cornea to progressively bulge into a cone-like shape making it more myopic and inducing astigmatism (think of the cornea becoming shaped more like a rugby ball than a football).  Normal activities such as driving and reading can be difficult to perform.

Although keratoconus rarely results in total blindness, 20% of all patients will at some time need to undergo a corneal transplant. 
Keratoconus is normally treated with rigid contact lenses to reshape and flatten the pronounced curve of the bulging cornea and to improve vision.  A proper lens fit is crucial to obtain adequate vision and wearing comfort. Poorly fitting or outdated contact lenses can be uncomfortable and lead to significant discomfort, corneal abrasions, scarring or infection. 
For keratoconus patients who are contact lens intolerant the goal of the INTACS procedure is to improve functional vision with contact lenses or glasses and in some cases without them.  The INTACS procedure does not prevent the eye having a corneal transplant at any future time if this is required, but INTACS may ultimately be found to delay or perhaps prevent the need for a corneal transplant, by helping to keep the cornea nearer to its natural shape.

INTACS inserts are an important additional option for keratoconus patients who are intolerant of contact lenses and whose only other option may previously have been a corneal transplant.

Corneal ectasia

Corneal ectasia is a condition resembling keratoconus but comes from a different origin.  Almost invariably the cause is refractive eye surgery that has resulted in a cornea that is too thin or too weak to withstand the normal internal pressure of the eye.  This can cause expansion or distension of the cornea, leading to increased myopia.  Most of the time a special gas permeable contact lens will be needed to restore vision.  INTACS can be used in the same way as for keratoconus.

How do INTACS inserts work?

Imagine your cornea as a tent with a curved top. If you push out the sides of the tent, the top flattens. Similarly, when INTACS inserts are placed in the sides of the cornea, they flatten it just enough to correct myopia

INTACS inserts change the curvature of your eye by adding ultra-thin ring segments.  They can be completely removed if necessary, returning your eyes to their preoperative condition.

INTACS insert being placed into a channel in the corneal periphery.

INTACS insert after positioning is complete 

Adding volume in the periphery of the cornea causes a flattening effect to reduce the curve of the cornea.  This reduces the degree of myopia and astigmatism, so improving the level of vision that can be achieved without glasses or contact lenses.  Furthermore, by reducing the corneal curvature, INTACS increase the likelihood of being able to fit and tolerate contact lenses. It may even be possible to use soft contact lenses to achieve the best visual result.

New INTACS SK

Mr Muhtaseb is one of only a few surgeons using the new SK inserts to treat severe keratoconus.  He performed 2 out of the first 3 INTACS SK operations in the UK, and was the first surgeon to implant INTACS in one eye and INTACS SK in the other eye of the same patient.

What happens after the operation?

There will be a single small stitch in the cornea, and you will be asked to put drops in your eyes for a few weeks.  The stitch will be removed after 3 months.
The shape of the cornea will typically take 3 months (or longer) to stabilise and during this time your vision will fluctuate.  Only once the cornea has become stable should you consider glasses or contact lenses for definitive correction of any residual refractive error.  Some people choose to seek temporary glasses or contact lenses during the recovery period.

What are the risks?

These are uncommon but may include:
Corneal infection, reduced visual acuity, extrusion of the implant, and glare or other visual disturbances which may be particularly notable in dim light if the pupil is wider than the INTACS inserts.  This is caused by a scattering of light around the edge of the INTACS inserts.  Some people may experience a lack of effect from the INTACS inserts.  It should be remembered that the INTACS procedure is reversible and may delay the need for a corneal transplant.

Summary

INTACS alters the curve of the cornea and may slow down the progression of keratoconus and corneal ectasia.  It may be used alone, or in conjunction with other treatments such as corneal collagen cross-linking (C3R) or phakic intraocular lenses, to produce the optimum visual result (see the relevant i.Lase information leaflets).  When the cornea has stabilised, glasses or contact lenses may be required to provide the best visual outcome.

Dr Mohammed Muhtaseb

As well as his full fellowships in corneal surgery and inflammatory eye diseases, Mr. Muhtaseb spent 9 months undertaking a full fellowship in refractive surgery, followed by independent practice as a Consultant in the United Kingdom.  This forms the foundation for advice and treatment that you can trust at i.Lase.