What Is Keratoconus?

What is Myopia Management for Nearsighted Children

Amplify EyeCare of Greater Long Beach
Dr. Eric Ikeda
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What is Myopia Management for Nearsighted Children

Amplify EyeCare of Greater Long Beach
Dr. Eric Ikeda
See more

A Layman’s Guide To Keratoconus

Keratoconus is a degenerative ocular disease where deterioration of the cornea causes thinning, brittleness, and a conical shape. As a result of this distortion in shape, light is unable to properly reach the retina, leading to impaired vision. In some cases, it leads to irregular astigmatism, as a result of two ocular curvatures.

Although there is no cure, there are several treatment options available, including various types of prescription contact lenses, a cross-linking procedure, surgical Intacs, and in severe cases, corneal transplant surgery.

Over the course of a patient’s life, some or all of these corrective measures may be implemented as the condition advances. Fortunately, with proper medical intervention, the risk of blindness is minimal. Nevertheless, as with all ocular disorders, appropriate care is critical to treat this condition and prevent deterioration. A comprehensive exam will enable the optometrist to make a diagnosis.

What Causes Progressive Keratoconus?

Although there is no definitive evidence of causation, studies strongly suggest that there may be a hereditary and genetic predisposition to this disorder:

  • Family history
  • There is evidence of comorbidity with Down’s syndrome, Ehlers-Danlos syndrome, hay fever, congenital amaurosis, and asthma
  • Aggressive eye-rubbing with the knuckles may be injurious.
  • Environmental factors such as climate may lead to eye-dryness and subsequent rubbing.

Signs of Keratoconus

As with many ocular disorders, signs present slowly and are hard to detect. Periodic comprehensive exams are critical for assessing vision changes, and monitoring and detecting progression of this ocular disease. Optometrists are able to identify indicators that go undetected by a layperson. The following signs may indicate the onset of this condition or other ocular disorder. Initial symptoms include:

  • distorted or blurry vision
  • sensitivity to bright light and glare. 

One of the difficulties with this condition is that early signs can remain the same for years. During the earliest manifestation, interventions may include standard corrective lenses. Swelling is rare.

  • Later interventions include permeable contacts, options for collagen cross-linking procedures to prevent further alteration, Intac insertions, and in severe cases, a cornea transplant.

Diagnosing Keratoconus

Diagnosing a patient requires comprehensive testing using the following diagnostic tools:

  • Corneal-mapping: This procedure enables a 3D representation and eye mapping.
  • Slit-lamp: This device enables a comprehensive look at the internal ocular structures.
  • Refraction tests: These permit an assessment of visual strength.
  • Keratometry: A test to measure corneal shape using reflection from a special light.

Treatments for Keratoconus

There are various options. As progression continues, treatment may include all or some of these options:

Contact lenses

  • Soft contacts: These standard lenses which provide increased comfort, may only be suitable for early cases of this disorder.
  • Hard contacts: As the disorder advances hard lenses are sometimes required. Although they may be uncomfortable, they provide impressive gains in vision. 
  • Advanced options: Hybrid types lenses combine the comfort of a soft lens with gas permeability. “Piggy-back” types refer to the technique where a type of lens is placed over another one to blend the functions of the two.
  • Scleral lenses: When the condition advances and the corneal damage is severe, these are used to rest on the sclera, creating a new ocular surface.

Collagen cross-linking: In this procedure, measures are taken to prevent further alterations. It is accomplished with riboflavin eye-drops and ultraviolet light. 33.3350

Intacs: A procedure where semicircular plastic rings are inserted to strengthen the 80cornea and prevent further alteration.

Cornea transplant: In advanced cases where contacts and glasses are no longer effective, a transplant may be necessary to replace damaged tissue. Frequently, contacts or glasses will be necessary post-surgery. Scleral lenses act as a new ocular surface when scarring or damage is extant. While surgeries are usually successful, risks include possible (albeit unlikely) rejection of tissue and infections. Post-surgical maintenance will monitor and treat these conditions, should they present.

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