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New technology billed as the latest breakthrough in laser vision correction arrives

Tuesday June 2 2015

Dr Mukesh Joshi attending to a patient with a corneal problem. The principle aim of laser vision correction is to reshape the cornea to correct vision problems. The reshaping is done to the middle part of the cornea, known as the stroma. Every year, more than five million people undergo laser vision correction. PHOTO | COURTESY

Dr Mukesh Joshi attending to a patient with a corneal problem. The principle aim of laser vision correction is to reshape the cornea to correct vision problems. The reshaping is done to the middle part of the cornea, known as the stroma. Every year, more than five million people undergo laser vision correction. PHOTO | COURTESY  

By ROSHNI WALIA

Do you wear contact lenses or glasses? What if you were told that you could get perfect vision by lying under a laser machine for 30 seconds without any surgical instruments touching your eye? It seems like a dream, but it is now possible, thanks to the C-Ten procedure.

Patients suffering from short-sightedness, long-sightedness or astigmatism (distortion of the cornea that causes blurry vision), which cause them to need glasses or contact lenses, now have access to a procedure that can correct their vision in less than half a minute. The procedure, which takes no more than 35 seconds, is minimally invasive as there are no surgical instruments involved.

The principle aim of laser vision correction is to reshape the cornea to correct vision problems. The reshaping is done to the middle part of the cornea, known as the stroma.

Every year, more than five million people undergo laser vision correction, and 95 per cent of people who wear contact lenses or glasses are suitable candidates for laser vision correction. 

The methods include: 

1. Lasik (Laser-Assisted in situ Keratomileusis): In this method, a thin flap of the cornea is cut and lifted in order to perform laser vision correction.

While this is a good procedure and is still very popular, it has a few drawbacks such as dry eyes, night driving problems, possibility of infection and other optical complications like weakening of the cornea. 

2. C-Ten (Customised Trans-Epithelial Non-Contact): Keeping the same principle in mind, no surgical manipulation is required, leading to a much safer procedure and quicker recovery.

The procedure is very popular in other countries, including Switzerland, Canada and Norway, and is now available for the first time in Africa and Asia. 

How does it work?

C-Ten is a technology where no instrument touches the patient’s eyes, and the laser machine is specialised to perform the treatment.

Prior to the treatment, to determine whether a patient is suitable for it, the surgeon checks the prescription of the patient’s glasses and rules out corneal and retinal diseases.

A special type of instrument known as Precisio is used to conduct mapping (topography) and thickness (tomography) of the cornea, and then the patient’s pupil is measured in different lighting conditions.

All this data is then collected and exported into the laser machine. On the day of the procedure, the patient is told to lie under the machine. After inserting an anaesthetic drop into the eye, a small clip is put in place to prevent blinking.

The patient is asked to look at a red fixation light. The surgeon activates the machine, and the procedure is done within 30 seconds. 

What steps are involved in C-Ten?

 Step 1: A doctor carries out an external examination of the patient’s eye and prescription of their glasses, and rules out contraindications. 

 Step 2: Topography and tomography is used to map the cornea and measure its thickness. Laser Eye Centre in Nairobi uses the Precisio machine, which provides a three-dimensional analysis of the front and back of the cornea, where 39,000 spots of the cornea are analysed. 

 Step 3: PMetrics is used to measure the size of the pupil in different lighting conditions. In low light, the pupil is larger than in bright light. Since pupilometry varies from person to person, it is important to measure how each patient’s pupils adjust to light and darkness. 

 Step 4: On the day of the surgery, the patient’s data is exported into the laser machine, and the procedure is carried out. 

What are the other benefits?

For corneal transplants, the diseased cornea is replaced by a donor cornea available from an eye bank. The most common cause of corneal transplant is Keratoconus, a condition prevalent among young people where the cornea loses its shape (the normal cornea is like a watch glass) and becomes like a cone. The new treatment for this condition is to flatten the cone and reshape the cornea.

When Keratoconus is very advanced, then a corneal transplant is warranted. Until now, traditional corneal transplants have been done, but now, with the new C-Ten laser, the irregular corneal shape is removed and the donor cornea put in place with a few sutures. This is a non-penetrative surgery, so the chance of corneal rejection is remote and recovery is much faster.

For patients with existing corneal transplants, some of the corneal transplants done in the past have led to poor vision due to distortion of the cornea (high astigmatism). The C-Ten laser machine can reshape the cornea and improve the vision of the patient.

After cataract surgery, some patients do not see well after cataract surgery, in spite of having healthy eyes. This could be due to high astigmatism, and such patients can also benefit from the C-Ten laser.

 

Frequently asked questions

  •  Is everyone who wears glasses or contact lenses suitable for this procedure? No, but about 95 per cent of glasses and contact lens users are. If you suffer from an existing corneal or retinal disease, Type 1 Diabetes, inflammation in the eye or Aids, it will not be possible to perform this procedure. 

  •  How good is the result? Doctors achieve perfect vision correction in 99.7 per cent of patients, which means that only three people out of every 1,000 will require a touch-up in the future. 

  •  If I have done Lasik or other laser vision correction before, can it be done again? Yes, but since it is not a virgin eye, the results cannot be predicted 100 per cent, and, rarely, there may be some surprises. 

  •  What if I am not suitable for C-Tten laser vision correction? There are other options if you do not qualify for laser vision correction. These are reflex surgery, in which the existing lens is replaced by an intra-ocular implant which replaces the previous spectacle prescription; or Phakic IOL insertion, which addresses refractive errors. Once in place, Phakic IOLs work together with the eye’s natural focusing system to deliver clearer vision.