The LASIK procedure, which corrects vision and allows patients to discard their glasses or contact lenses is a popular procedure. However, ophthalmologist Dr. Jonathan Pirnazar who is affiliated with NVISION Laser Eye Center in Ontario, California, warns that individuals with a genetic eye disease can be rendered blind by LASIK. He explained that Avellino corneal dystrophy (ACD) is a genetic eye disease that causes cloudiness, specifically grey-white granular deposits, on the various layers of the corneas (the transparent outer covering of the eye), which can lead to complete loss of sight. ACD is caused by a genetic mutation and usually develops slowly. Most patients that he has seen with this condition may be able to see with the aid of contact lens or glasses. However, if carriers of this genetic mutation undergo LASIK, they are at an extremely high risk of experiencing diminished vision and eventual blindness.
Fortunately, a test is available that can check for ACD. Dr. Pinazar’s facility now offers the test to every patient who requests LASIK. The Avellino – GENE Detection System (AGDS) is administered by an ophthalmologist via a simple mouth swab. It currently is the only test available for ACD and has protected many people from vision loss; thus, it is becoming a preferred pre-screening test by ophthalmologists for evaluating patients who seek corrective vision laser surgeries. This test has been proven to have 100% accuracy in identifying the genetic mutation.
Dr. Pinazar explained that the number of individuals with ACD worldwide is currently unknown. In Asia 1 in 870 people are found to be positive carriers of the condition. The AGDS was originally developed in Asia and was introduced into the U.S. in January 2013. Testing currently underway will determine the prevalence rate among LASIK candidates specifically in the United States. He notes that cases of the genetic mutation in all racial groups around the world but rate of incidence will vary by population group.
The degree of vision loss among ACD sufferers ranges from mild to severe. Other conditions can exacerbate (speed up) the progression of ACD such as other genetic factors, environment (e.g. excessive UV exposure), and age. In these individuals with coexisting conditions, vision impairment can progress fairly rapidly to complete loss of vision. Documented case studies have shown mild and severe cases.
Symptoms of ACD can include blurred vision or decrease in vision. The ACD genetic mutation causes the normal proteins involved in the wound healing process to be produced in excess quantities. Over time, the excess protein will form deposits in the cornea that gradually increase in density; thus, increasing vision impairment. ACD usually develops slowly. However, carriers of this genetic mutation are at an extremely high risk of experiencing diminished vision and eventual blindness should they undergo vision-correction refractive surgery such as LASIK, LASEK, PRK, or PTK.
The genetic mutation is an autosomal dominant, meaning that if a parent has the genetic mutation, there is a 50% chance that each of their children will have the mutation. If an individual has two copies of the mutated gene, deposits on the cornea begin appearing around three years of age, usually causing blindness by adolescence. The condition develops more slowly in individuals with one copy of the gene. In these individuals, white spots may begin to appear on the cornea around the age of 12; however, the individual may have no symptoms until much later in life. Thus, carriers of one copy of the gene may have no symptoms prior to undergoing LASIK. The procedure can exacerbate ACD, resulting in increased cloudiness of the cornea, which can progress to complete loss of vision. Research indicates that this may occur as soon as four months or as late as 17 years after the LASIK surgery.
I asked Dr. Pinazar what the test costs; he told me that it amounts to a small fraction of the total cost of LASIK, and most clinics, including NVISION, are choosing to incorporate the test into the total cost of the surgery. NVISION incorporates the AGDS Test into the total cost of the LASIK surgery. In addition, NVISION is currently using the AGDS Test as part of the general eye exams; specifically, when the doctor is examining the cornea with the slit lamp. Some individuals who carry the ACD genetic mutation do not express symptoms observable by slit lamp examination during the first half of life. Therefore, the AGDS DNA Test is the only way to determine if the risk of LASIK outcome is present. NVISION chooses to perform the AGDS Test with LASIK candidates because it is committed to LASIK safety.
NVISION recommends the AGDS test to all LASIK candidates to add to the predictive outcome for the safest post-LASIK outcome. In our office, about 20-30% of our LASIK patients are opting to get tested. In Asia, where the test was first introduced, more than 80% of all LASIK patients are tested as a standard of care. Avellino Lab USA intends to progressively broaden geographic access to the AGDS Test so that it can become more available to physicians and their patients across the country.
Unfortunately, there is no cure or treatment for ACD. However, with the AGDS test, a patient can determine if they have ACD prior to undergoing LASIK, avoiding the risk of blindness should they have ACD. If an individual is identified as positive for the genetic mutation, they will be advised against having LASIK surgery and encouraged to take protective measures (e.g. minimizing exposure to UV light by wearing appropriate protective lenses) to help postpone progression of ACD symptoms. This significantly contributes to a safe outcome of the LASIK procedure. Phototherapeutic Keratectomy (PTK) may provide temporary relief; however, the lesions may reoccur where the laser was applied years later.