Navi Mumbai Eye Clinic and Laser Centre
Doctors serving Navi Mumbai since 2002

Keratoconus Surgeries

Keratoconus is corneal degenerative disorder, wherein the corneal shape changes to a more conical one over a period of time, hence the name. (Kerato = cornea, conus—conical shape).

There is associated corneal thinning which can be irregularly spread over the surface, which can cause this bulging or protrusion. This causes distortion of light rays focusing on the retina, thus affecting the vision.  

 

Causes

  • Genetic
  • Allergic disorders which cause
      habitual eye rubbing
  • Systemic abnormalities like
      Down ’s Syndrome, etc.
 

Symptoms and signs

  • Progressive increase in spectacle
      number, especially the cylindrical power
  • Distorted and blurred vision
  • Glare, light sensitivity
  • Headache and eyestrain

 

 

Keratoconus often begins to develop in the teen years to the early 20s, although it can develop at any age. Changes in the shape of the cornea occur gradually, usually over several years. In most patients with keratoconus, both eyes eventually become affected.

A detailed evaluation includes a spectacle check-up, corneal curvature (topography) and thickness measurements (pachymetry) by various means. The corneal curvature and thickness maps will tell us the severity of the disorder.

 

Treatment

Contact lenses

In early stages, contact lenses are the best option, and they give maximum benefit with good clarity of vision. The lens worn on the eye surface corrects the irregularity and thus reduces the light scattering.

 

 

 

Rigid Gas Permeable (RGP) lenses

Later on, as the irregularity increases, soft lenses are not of much use.

Rigid gas permeable lenses are then used, which offer good results—they give their shape to the irregular cornea beneath, thus improving the irregularity.

However rigid lenses are slightly less comfortable on the eye. Fitting a rigid lens on a patient can often be challenging and time consuming. In later stages, special fit lenses of various brands are available, to give comfort to the patient.

Corneal Cross Linking

This procedure works by attempting to strengthen the collagen meshwork of the corneal stroma. It involves use of riboflavin (vitamin B2) eye drops and a laser beam which then activates the riboflavin, which results in increasing the bonding between the collagen fibres in the stroma, thus attempting to halt or slow down the progress of the disease.

Intacts

These are special rings which are inserted into the corneal stroma, which help in flattening the irregularity and when contact lenses are no longer able to control the irregularity of the surface. They are a relatively low risk procedure, lasting about 15 minutes.

A laser is used to fashion a stromal tunnel, where the rings are then inserted. These rings help to flatten the corneal surface, and reduce the astigmatism.

Corneal Transplant

This is the last option when all the above options have failed in reducing/arresting the progress of the irregular astigmatism, and when the vision has dropped considerably.

Corneal transplant can be either full thickness grafting or partial thickness, depending upon the extent of damage in the patient’s own cornea.

 

 

What Is Corneal Transplant?

The cornea is the outer transparent layer of the eye, which helps in focusing the light rays onto the retina.Whenever this becomes hazy or cloudy, the vision is affected.

Causes of haziness include:

  • Infections
  • Trauma or injury
  • Degenerative conditions
  • Corneal dystrophies

Following Intra ocular surgery

Transplantation includes removal of the diseased cornea and replacing with a new cornea (obtained from an eye bank).

A circular disc of corneal tissue is removed from the patients eye (diseased cornea) and then replaced with a donor cornea (healthy cornea), which is secured in place by sutures. The procedure can last for about 30-60 minutes. Post-operation, vision stability is usually attained after about 3-6 months.

A careful follow up is required, to detect graft rejection by the patient’s own immune mechanism, which can cause haziness in the donor cornea, negating the benefits of the transplant.

Lamellar Corneal Transplant

The traditional corneal transplant involved a full thickness corneal button removal and subsequent grafting.

The cornea anatomically has 5 layers.

The gross pathology which can affect the cornea and cause clouding are either the middle stroma or the innermost endothelium.

Traditionally, in corneal transplants, the entire cornea was replaced with a donor tissue.

But with technological advances, however partial thickness grafts are also feasible today—the advantage being removal of only the diseased portion of the cornea, leaving the healthier tissue back.

The two techniques in vogue today are:

DALK (Deep Anterior Lamellar Keratoplasty)—removes the superficial layers only, leaving the healthier inner layers of the cornea intact.

DSEK (Desemet Stripping Endothelial Keratoplasty)—the innermost diseased layer is removed, keeping the outer layers intact.