Keratoconus is caused by a thinning of the cornea, which transforms the surface of the eye from a round sphere to a cone shape. This affects the way that light enters the eye and can cause blurry or distorted vision. Although keratoconus usually progresses slowly, early detection is vital to ensuring the most effective, minimally invasive treatment options. Several of the doctors at Silicon Valley Eye Physicians have undergone extensive training and managed hundreds of keratoconus cases throughout their careers. Additionally, both offices in Sunnyvale and Santa Clara, CA, are equipped with advanced diagnostic technology and custom contact lens design and manufacturing equipment to help you receive treatment that addresses your unique needs.
What Is Keratoconus?
Keratoconus affects your cornea and is caused by a weakening of the collagen bonds that provide structure and stiffness to the corneal tissue. When these bonds weaken, the cornea can bulge outwards in a cone-like shape and cause vision issues including nearsightedness, blurred vision, and sensitivity to light. Although each patient experiences keratoconus for different reasons, certain factors may increase your risk including:
- Intense sun exposure
- Excessive rubbing and irritation
- Contact lenses that do not fit correctly
- Enzyme imbalance
- Genetic disposition
As the severity of keratoconus progresses, your vision usually becomes more blurry and distorted. Eventually, the shape of the cornea can make wearing contacts uncomfortable or impossible.
We have managed hundreds of cases of patients who suffer from keratoconus and are equipped with the training and technology to create custom contact lenses.
A Closer Look at Causes
The precise cause of keratoconus is unidentified. There are many theories based on research. However, no one theory explains it all and it may be caused by a combination of factors.
One hypothesis is that keratoconus is genetic because in some cases there does appear to be a familial association. From the currently available information, there is less than a one in ten chance that a blood relative of a keratoconic patient will have keratoconus. The bulk of patients with keratoconus do not have other family members with this disease. Studies show that keratoconus corneas lack vital anchoring fibrils that structurally stabilize the cornea, which allows that cornea to “protrude forward” into a cone-shaped appearance.
Eye Rubbing: Keratoconus corneas are undoubtedly damaged by minor trauma such as eye rubbing. Poorly fit contact lenses that rub against the irregularity of the KC cornea have been implied as a possible cause of keratoconus.
Allergies: Many who have keratoconus report forceful eye rubbing and also have allergies, which result in itching, leading to eye rubbing, however the link to allergic disease also remains unclear. A higher percent of keratoconic patients have disorders such as hay fever, eczema, asthma, and food allergies, which are considered atopic diseases.
Hormonal: Another hypothesis is that the endocrine system may be involved because keratoconus is generally first detected at puberty and may progress during pregnancy. This theory has not been proven.
Signs & Symptoms
The earliest signs of keratoconus are typically blurred vision and recurrent changes in eyeglass prescription, or vision that cannot be improved with glasses. Symptoms of keratoconus commonly begin in late teenage years or early twenties, but can start at any time.
- Patients may report the additional following symptoms:
- Difficulty driving at night due to increased light sensitivity and glare
- A halo around lights and ghosting (especially at night)
- Eyestrain, distorted images.
- Headaches and general eye pain and discomfort.
- Eye irritation, excessive eye rubbing
Diagnosing the Condition
Keratoconus can typically be diagnosed with a microscopic slit-lamp examination. The characteristic signs of keratoconus that the doctor will observe when examining Keratoconic eyes include:
- Corneal thinning, measured by Pachymetry
- Distorted corneal curvature as measured by Topography.
- Fleischer’s ring – an iron colored ring surrounding the cone
- Vogt’s striae - stress lines caused by corneal thinning
- Apical scarring – scarring at the apex of the cornea
- Irregular mires on Keratometric exam
Early Detection Of Subclinical KC
Drs. Li, Yang, and Rabinowitz conducted a longitudinal study at the Cornea-Genetic Eye Institute, Cedars-Sinai Medical Center in Los Angeles, California to determine whether there would be a correlation between corneal topography and clinical signs of keratoconus that might be used for early detection of subclinical keratoconus. The study results established that there were significant differences at baseline topographical and Keratometric measures between the normal, keratoconus-suspect, and early keratoconus groups in all indices. Over a median follow-up of 4 years, approximately 28% in the keratoconus-suspect group progressed to early keratoconus and 75% in the early keratoconus group progressed to advanced keratoconus.
Although keratoconus is a chronic condition, we can provide several conservative treatment options to restore function and comfort to your vision.
Scleral Contact Lenses
Currently considered the gold standard in the treatment of keratoconus, these lenses can provide extensive benefits for patients with keratoconus. In our experience, these lenses provide the best outcomes for patients with keratoconus. Scleral lenses cover a larger portion of the eye and can help you achieve long-lasting, sharper vision with a reduced risk of complications from contact lenses.
Hybrid lenses, also known as SynergEyes®, combine the comfort of a soft lens with the function of a hard lens. For patients who are not good candidates for scleral contact lenses, we may recommend hybrid lenses.
Corneal Collagen Crosslinking (CXL)
CXL with Riboflavin (CXL) is an emerging keratoconus treatment. CXL works by increasing collagen crosslinks, which are the natural “anchors” within the cornea. These anchors are accountable for inhibiting the cornea from bulging out and becoming steep and distorted.
After patients have been successfully fit with contact lenses, a moderate percentage of complications and unfavorable reactions are related to skipping or modifying the prescribed method for cleaning, disinfecting, and storing their lenses. Compliance is the key to long-term success for all contact lens wearers. It is especially important for keratoconus patients, since they are virtually totally dependent upon contact lenses for all their visual tasks. Eye infections, while rare, can be harmful, preventing patients from wearing their contact lenses for days and occasionally may result in long-lasting corneal scarring and loss of vision. A comprehensive understanding of the role played by each of the rigid gas permeable lens care products will help keep lenses clean and eyes healthy.
Call for a Consultation
Several of our doctors have completed extensive training in the diagnosis and treatment of keratoconus. Together, we have managed hundreds of keratoconus cases and are equipped with the skills and technology to create custom contact lenses which help to uniquely address your condition. Schedule a consultation today by calling our Sunnyvale office at (408) 739-6200 or our Santa Clara office at (408) 739-4444. Patients can also send a message to our friendly staff by using our contact form.