Keratoconus Management

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What is Keratoconus?
Keratoconus is a disease of the cornea (the curved, clear front surface of the eye) that is often visually debilitating. In Keratoconus there is progressive thinning of the cornea and as a result the cornea develops a cone-like bulge and becomes distorted. The distorted cornea affects the focusing ability of the eye impairing the vision.

Does Keratoconus cause blindness?
No, Keratoconus does not cause total blindness. If left untreated, Keratoconus can however lead to significant vision impairment resulting in legal blindness.

At what age does Keratoconus develop?
The onset of Keratoconus can be anywhere between the ages of 8 and 45. In the majority of cases, Keratoconus presents between the ages of 16 and 30 years. Keratoconus usually develops in both eyes, but the condition may be significantly advanced in one eye.

What causes Keratoconus?
The exact cause of Keratoconus is still unknown however risk factors for developing Keratoconus have been identified including having a family history of Keratoconus, allergiesand excessive eye rubbing.

Signs and symptoms of Keratoconus
The signs and symptoms of Keratoconus can include;
• Blurring and distortion of vision that may be corrected by spectacles in the early stages of the condition
• Irregular astigmatism (irregular curvature of the cornea)
• Short-sightedness (myopia)
• Frequent changes to the spectacle prescription
• Once the condition has progressed it is often difficult to satisfactorily correct the vision with glasses.

How is Keratoconus diagnosed?

1. History of frequent changes of the spectacle prescription

2. Use of some advanced investigation and diagnostic tools such as scout and Sirius topography which is available in Dr. Haifa Eye Hospital. Schwind’s Sirius Topography gives ‘3D’ details of anterior and posterior cornea and also gives corneal thickness within few seconds.

Treatment:

1. Eye glasses and contact lenses can correct the refractive error but cannot stop or prevent the progression of Keratoconus. We are providing special contact lenses such as Rose K lenses and Hybrid (Clearkone) contact lenses

2. Clinical studies nowadays demonstrated that progressive Keratoconus can be stabilized by (Corneal cross – linking procedures.

In this procedure riboflavin (vitamin B2) drops instill into the cornea at the rate of one drop every 2 minutes for 30 minutes. Then the UV radiation treatment exists for 30 minutes. Reaction of riboflavin with UV radiation strengthens the corneal tissue. The progression of the corneal thinning is slowed or even stopped.

3. Myoring Implantation using FEMTO laser: Now a day several types of intra corneal rings are available to improve vision for Keratoconus patients such as 360 º flexible rings (Myoring), INTACS, keraring and Ferrara ring.

These types of ring surgically implanted into the cornea to flatten the corneal surface and improve vision with Keratoconus. Dr. Haifa Eye hospital provides new technology which is combined cross-linking with riboflavin (Vitamin B2) +Myoring implantation. Every 2 minutes Riboflavin is applied over the cornea. During surgery Myoring is being inserted to the pocket which was created by LDV (FEMTO laser) machine. Then UV radiation applied over the cornea only for 15 minutes. Finally 360º ring placed in to the pocket. This procedure can be done under topical anaesthesia and save time.

Lamellar Keratoplasty
1. Anterior Lamellar Keratoplasty (ALK)
In most Keratoconus cases, the innermost layer of the cornea - the endothelium, is healthy. (This is the functional layer of the cornea that contains cells that pump fluid out of the cornea and maintain its clarity.) However in full thickness corneal transplantation procedures (conventional corneal grafting surgery) this layer is also sacrificed and replaced with donor tissue. The body senses this layer as being foreign and attempts to reject this tissue. Hence post-operative steroid medications are necessary for a long time post-operatively to prevent rejection of the corneal graft. Long term use of steroids can predispose to complications such as cataract and glaucoma, besides the increased risk of secondary infection.

2. Deep anterior lamellar keratoplasty (DALK), is a newer method of corneal surgical procedure. It is a partial thickness graft that selectively removes the diseased anterior layers of the cornea and preserves the two healthy innermost layers, the endothelium and Descemet’s membrane. As the inner lay ers are retained the body does not recognize the donor tissue, hence there is less risk of rejection, and steroid medications need not be continued for a long duration.

Penetrating Keratoplasty (full thickness corneal transplant):
When the above mentioned treatment is not suitable for you, and a contact lens cannot be fitted satisfactorily despite all measures, the conical cornea must be replaced surgically. Keratoplasty (Corneal transplantation or grafting) is an operation in which abnormal host tissue is replaced by donor corneal tissue. Penetrating Keratoplasty is the procedure of choice, and virtually all authorities cite success rates greater than 90%. The donor tissue is fixated onto the host by means of multiple interrupted sutures.