Keratoconus - Symptoms, Diagnosis, and Treatment
Keratoconus is a vision disorder which causes the cornea to become thin and irregular in shape. Symptoms include blurred vision, which is worse at night, and distortion of images that are not fully corrected by glasses. Good vision normally restores by use of contact lenses. In younger patients, Keratoconus is often a progressive disease.
Cross-linking is an excellent option in patients where the cornea is becoming more out of shape. It is a relatively simple and effective treatment at halting the progression of keratoconus. There is some evidence to show that in the long-term, particularly in younger patients, there is a degree of normalisation of the corneal shape. It is a relatively simple day case procedure. It has proven in long-term studies to possess over 95% success rate in halting the worsening of the condition. Also, it has a low risk (less than 1% of complications).
The epithelium of the cornea is removed. B-vitamin (riboflavin) is applied to the cornea for approximately 30 minutes. Thereafter, ultraviolet light is applied to the cornea for approximately 10 minutes. Cross-linking is thought to strengthen the cornea by increasing the number of molecular bridges between the collagen fibres that make up the corneal stroma
Topography (Shape) Guided Laser
The main problem with Keratoconus corneas is that they are evenly out of shape. This is why specifically designed contact lenses; which sit on the front of the cornea, work so well. The contact lens presents an even shape to the light as it is entering the eye.
For early keratoconus, where there is enough corneal tissue; modern technology can map the front of the corneal surface. It can use this map to apply the laser to smooth out the contours of the corneal surface. A more even cornea gives better quality of vision. Each cornea is mapped and treated an entirely customised basis. Cross-linking procedure is done afterwards to strengthen the remaining cornea. Without a doubt, in suitable cases, this is my treatment of choice for keratoconus.
Kerarings are a type of ICRS (intra-corneal ring segment). Their purpose is to reshape or regularise the shape of the cornea to help improve the vision. They are particularly useful for patients who find contact lenses uncomfortable. A highly precise femtosecond laser is used to make a tunnel within the cornea. The segments are then placed into these tunnels. The size shape and position of the rings are specifically calculated for each individual cornea to help optimise results.
In cases of advanced Keratoconus, or where there is corneal scarring, a corneal transplant may be the best option. This is my advice as the best keratoconus specialist in Yorkshire.
When the cornea becomes cloudy due to scarring and insufficient light is transmitted into the eye, a transplant involving the Stroma may become necessary. This may become necessary due to corneal infections traumatic damage to the cornea, or advanced forms of keratoconus.
There are two main forms of transplantation that involve replacing the corneal stroma. A full-thickness or penetrating keratoplasty involves transplantations of all the layers of the cornea. A DALK (Deep Anterior Lamellar Keratoplasty) involves transplantation of all the parts of the cornea, apart from Descemet’s membrane and the endothelium.
Both these forms of transplantation require stitches or sutures to the cornea. The recovery period takes between 6 and 18 months.
Although it is not possible for all cases, a DALK usually keeps the eyes structurally more intact. It also negates the risk of rejection or regression involving the endothelium.