Topoguidedprk-uvx - Envision Eye Centre


Laser vision correction has traditionally not been available for those with keratoconus. The disease in some patients has progressed to a point where vision is no longer useful in the eye. Collagen cross-linking on its own cannot always be relied upon to improve vision. Newer techniques have been brought out to combine Topography Guided Laser Vision Correction (PRK) combined with collagen cross linking to strengthen the cornea changing it from a cone shape and promoting flattening of the cornea to reduce astigmatism and restore vision.  By combining the laser treatment with cross linking a further the strength of the cornea is enhanced to reduce the risk of further progression of the disease. 

At Envision Eye Centre we have the newest technology to plan this procedure. Planning is the most important step in a good visual outcome. Dr John Males has invested in the newest ophthalmic equipment for this planning. Before the procedure you will require a full examination including refraction, two forms of corneal topography (mapping the cornea), and including scanning with the Pentacam and SIrius Corneal Topographers. 

This procedure is not the same as performing laser vision correction in the normal eye. The aim is to maximise vision, not cure the condition, and in some circumstances other treatments such as corneal transplantation may be required in the longer term. 

On the day of your surgery 

After topical anaesthetic drops are placed in the eye the laser is applied to the corneal surface with a “no touch” technique. The laser treatment itself takes less than one minute in most cases. The next step is to apply riboflavin drops to the eye. Following the instillation of the drops a UV light is applied to the eye.   

Riboflavin in conjunction with a specialised dose of ultraviolet light increases the number and strength of collagen bonds in the cornea. This is done in an effort to either delay or negate the need for further treatment in the future such as a corneal transplant  and reduce dependence on glasses or contact lenses.

After Topography guided PRK and collagen cross linking

There is some discomfort associated or the first few days after the treatment, pain relieving tables are given to assist with this phase of healing. A “bandage” contact lens is placed in the operated eye for the comfort of the patient. This lens is removed after 4-5 days, the vision is generally quite hazy and blurry shortly after surgery and takes several weeks to settle. 

It is important that after you have this procedure that patients attend all post-operative visits so refraction can be monitored closely.   

The outcome is dependent on how advanced the keratoconus is. The treatment is designed to reduce the strength of glasses or contact lenses, and unlike regular laser vision correction you may still require glasses or contact lenses to obtain the best vision possible, although the strength of the prescription is reduced in most cases. 

An example of what can be achieved with this technique can be seen here.