#WorldKeratoconusDay and let us join together to raise public awareness about keratoconus
World Keratoconus Day (National Keratoconus Day) was established in 2016 by the National Keratoconus Foundation. Keratoconus (KC) is a degenerative condition of the eye in which the normally round, dome-shaped cornea becomes progressively thinner and causes a cone-like bulge to develop in the area where the cornea is thinnest- usually in the center.
Keratoconus occurs in about 1 out of every 2,000 people in the general population and it is found in all parts of the world and in all ethnic groups. If left untreated, Keratoconus could lead to significant visual impairment and legal blindness.
The origin of the condition, Keratoconus, has been unknown and greatly debated. Environmental and genetic factors have been investigated widely, along with the recent addition to the factors – the component of inflammation. Scratching and rubbing the eyes and applying strong pressure on them triggers keratoconus and keratoconus is often associated with ocular allergy and vernal keratoconjunctivitis. While Keratoconus had been identified a century ago, in the past two decades the technological development has lead to substantial changes in its management and diagnosis. However, with a wide range of technological developments and the changes, a number of questions and controversies have also made their way.
There is strong association of eye rubbing and keratoconus, although eye rubbing is not necessarily sufficient to generate keratoconus in all patients who rub. Repeated eye rubbing episodes constitute the necessary ingredient to develop keratoconic changes in the cornea. This is a key observation, as the suppression of eye rubbing offers the possibility of halting the progression of the disease, and even the opportunity to eradicate keratoconus.
Clinical Presentation of Keratoconus:
Keratoconus often affects both eyes, and can lead to very different vision between the two eyes. Symptoms can differ in each eye, and they can change over time. In the early stage, keratoconus symptoms can include: mild blurring of vision, slightly distorted vision, where straight lines look bent or wavy; increased sensitivity to light and glare, eye redness or swelling . In later stages, keratoconus symptoms often include: more blurry and distorted vision, increased nearsightedness or astigmatism (when your eye cannot focus as well as it should). As a result, the patient may need new eyeglass prescriptions often. Patient of keratoconus may not being able to wear contact lenses. They may no longer fit properly and they are uncomfortable.
Keratoconus usually takes years to go from early to late stage. For some people, though, keratoconus can get worse quickly. The cornea can swell suddenly and start to scar. When the cornea has scar tissue, it loses its smoothness and becomes less clear. As a result, vision grows even more distorted and blurry.
Diagnosis: Keratoconus (moderate to severe) can be diagnosed clinically using slit lamp biomicroscopy and early keratocnus can be detected utilizing the topographer. This approach for its diagnostics may have been enough when the options for treating Keratoconus were restricted but with the emergence of CXL (Corneal Collagen Cross-Linking) became a game changer. When full thickness keratoplasty is done, the intervention is merely done at the rather advance stage when the disease is obvious. Now, with so many advancements, the surgeons have the ability and tools to prevent or even eliminate the progression through CXL. This has changed the goals from trying to enhance the vision that has already decreased to stopping a decrease in vision. But, this can be done when the disease is identified at an earlier stage.
Treatment of Keratoconus: The primary treatment mode was the usage of rigid contact lenses, and at present mini-sceral contact lens is gaining popularity. However, after the advanced development in the past decade, there have been various therapeutic options now available that have revolutionized the treatment approach for this disease. There has been a paradigm shift from the preferred Keratoconus treatment option from fitting of contact lens, followed by Deep Anterior Lamellar Keratoplasty (DALK) or Penetrating Keratoplasty (PK) to Ultraviolet-A (UV-A) induced collagen cross-linking (CXL) for stabilizing the corneal ectasia for long term. The recent advances in Keratoconus treatment has introduced the usage of excimer laser application, Phakic IOLs, Intrastromal Corneal Ring Segments (ICRS), as well as the utilization of combination techniques which have resulted in a major contribution to offer effective management options for Keratoconus at different stages of its progression. The newest technique is the Bowman layer (BL) transplantation which has been introduced recently as a substitute to PK/ DALK for Keratoconus at advance stage, unsuitable for ICRS or UV-CXL.
Newer Perspective of Diagnosis and Management: As per the recent consensus, the elevation of posterior corneal surface has been declared a must for diagnosing at early stage. The curvature of posterior corneal surface is the first thing to show up which makes it easier for early detection. This recent criterion was determined after the latest developments in the imaging processes, including Scheimpflug photography and optical coherence tomography. This is why unusual curvature of posterior corneal has been recognized as important parameter in the keratoconus diagnosis as the latest equipment can instantly highlight the elevation. Before this, the surgeons could only used to depend on a few instruments, like topographers, which merely detected the steepening of anterior corneal surface. Aside from this, there have been other factors that have been identified for keratoconus diagnosis including clinical non-inflammatory thinning and unusual distribution of corneal thickness. The numeric values for all these factors haven’t been specified by experts as they believe they can vary as per the measuring devices.
Another recent perspective on keratoconus diagnosis has been regarding the progression of the condition. Progression identification has become vital in treating as well as timely decisions. It is essential for the constant presence of at least two of the following parameters :
• Steepening of the surface of anterior corneal surface
• Steepening of the surface of posterior corneal surface
• Enhanced rate of thickness changes or/and thinning of corneal thickness from periphery to the thinnest point.