RNFL loss tied to slower reaction times

Glaucomatous structural damage may affect an individual's ability to divide attention when performing daily tasks such as driving, according to research recently published online.

Researchers at the Hamilton Glaucoma Center, University of California San Diego, USA, conducted a cross-sectional observational study of 158 subjects from the Diagnostic Innovations in Glaucoma Study: 82 subjects with glaucoma and 76 controls of similar age.

The researchers measured the subjects’ reaction times to peripheral stimuli at low, medium, or high contrast while the subjects performed simulated driving tasks such as negotiating a curve or following another car.

They discovered that the glaucoma subjects' mean reaction times to the low contrast stimulus were 1.19 seconds for car following and 1.05 seconds for curve negotiation. The control subjects’ reaction times were 0.77 seconds and 0.64 seconds, respectively, for the two tasks.

A non-linear relationship was found between reaction times and the retinal nerve fibre layer thickness (RNFL) in the subjects’ better eye. After the researchers adjusted for factors such as age, cognitive ability and standard automated perimetry deviation in the better eye, RNFL thickness still remained significantly associated with reaction times.

"Information from structural tests may improve our ability to determine which patients are likely to have problems performing daily activities, such as driving," the researchers concluded.

To read an abstract of the study visit the American Journal of Ophthalmology.