test for post glare LASIK
Flap Zero wrote:
The CAA document states that there must be no problems with glare following LASIK. Do they do a tangible test for that or is it entirely subjective?
Do Gatwick measure your vision under low light conditions? Check for halos/starbursts?
There is no recognised clinical test to measure glare, haloes/starbursts, so it is subjective. However its existance can be demonstrated.
One method is to use what is called a contrast sensitivity chart, there are several types eg Pelli-Robinson, or Balliey-Lovie LogMAR. Here you compare on say a LogMAR chart the visual acuity at high (90%) contrast and then at low(10%) contrast. The normal difference being about 1 line more than that will indicate possible glare problems.
A glare source on such charts may just be the use of a simple spotlight, however there is also a test know as the Brightness Acuity Tester, which requires the subject to view a test chart through a hole in a bright disc.
So it is possible measure and check for glare etc, but it is mainly a subjective response.
There is one further caveat in that the more modern methods of refractive surgery treatments have much reduced levels of glare/starbursts/haloes as a complication of the surgery. I am afraid I do not have any current statistics to hand.