A Corneal Biomechanics test is a vital diagnostic evaluation performed during a workup for LASIK and other refractive surgeries. This advanced, non-contact test measures the structural integrity and stability of your cornea. By understanding how your cornea responds to pressure, we can ensure you are an ideal candidate for vision correction surgery.
What is a Corneal Biomechanics (ORA / Corvis ST)?
Corneal Biomechanics is a sophisticated diagnostic procedure that assesses the cornea’s ability to resist deformation and its elasticity. Using state-of-the-art technology like the Ocular Response Analyzer (ORA) or Corvis ST, the test applies a gentle, calibrated puff of air to the eye. A high-speed camera then captures and analyses how the cornea bends inward and returns to its original shape, providing crucial data on its structural strength, including metrics like Corneal Hysteresis (CH) and Corneal Resistance Factor (CRF).
Why is this test performed?
This test is essential for ensuring the long-term safety and success of refractive procedures. Key reasons include:
Screening for Keratoconus: It is highly effective at detecting early or subclinical forms of keratoconus, a condition where the cornea thins and bulges, which is a major contraindication for LASIK.
Determining LASIK Candidacy: The test helps your surgeon confirm that your cornea is strong enough to withstand the laser procedure, significantly reducing the risk of post-surgical complications like corneal ectasia.
Accurate Glaucoma Assessment: Corneal rigidity can affect intraocular pressure (IOP) readings. This test helps provide a more accurate, cornea-compensated IOP measurement, which is crucial for glaucoma management.
Monitoring Corneal Health: It allows specialists to track changes in corneal properties over time, especially after treatments like corneal cross-linking for keratoconus.
How to Prepare for Your Corneal Biomechanics (ORA / Corvis ST)
There is very little preparation required for this quick and painless test. It is a non-invasive procedure that does not require any eye drops or physical contact with your eye, other than a gentle air puff.
You must inform your ophthalmologist about any pre-existing eye conditions or medications you are taking.
If you wear contact lenses, you will be instructed to remove them for a specific period before the test to allow your cornea to return to its natural shape.
Avoid wearing eye makeup, as it can interfere with the device’s sensitive optics.
The Procedure: What to Expect Step-by-Step
The entire process is quick, simple, and comfortable.
1. You will be seated in front of the diagnostic machine, resting your chin and forehead comfortably on the designated supports.
2. You will be asked to look straight ahead at a small fixation light and keep your eye open.
3. The instrument will release a single, gentle puff of air towards your eye. The sensation is brief and completely painless.
4. An ultra-high-speed camera records the cornea’s movement in response to the air puff, and the onboard software instantly analyses the data. The process is then repeated for the other eye.
Understanding Your Results
The results of your corneal biomechanics test are presented as numerical values and graphical data that your ophthalmologist at Pristine Eye Hospitals will interpret. The key measurements, such as Corneal Hysteresis (CH), indicate the cornea’s shock-absorbing capacity, while the Corneal Resistance Factor (CRF) reflects its overall rigidity.
Low readings may suggest a weaker, more flexible cornea that could be at risk for ectasia, potentially indicating keratoconus or ruling you out as a candidate for LASIK. Your doctor will carefully analyse these findings along with other diagnostic tests, like corneal topography, to make a definitive assessment of your corneal health and suitability for vision correction surgery.
Frequently Asked Questions
Is the Corneal Biomechanics test painful?
No, the test is completely painless and non-contact. You will only feel a gentle puff of air on your eye for a fraction of a second.
How long does the ORA / Corvis ST test take?
The entire process is very quick, typically taking less than a minute for both eyes. The data acquisition for each eye happens in a matter of seconds.
Why is this test necessary if I already had a cornea scan (topography)?
While topography maps the cornea’s surface shape, biomechanics measures its structural strength. Combining both tests gives your surgeon the most comprehensive understanding of your cornea’s health and stability.