Cataract surgery is generally not performed on both eyes together. In hospitals and surgery centers with advanced technology, the gap between the surgeries of the two eyes can be between 5 to 15 days. During this period, elderly patients find difficulty in driving. Visual acuity is generally tested after a cataract surgery, but what should also be tested, for issuing a drivers license, is the contrast sensitivity in both the eyes.
Contrast sensitivity is the ability to see at low contrast conditions like sleet or fog, or even perceive light colored objects against a light colored background. After a cataract surgery procedure, the patient’s contrast sensitivity increases only in the eye which has been operated, and not in the other. This causes a disparity in the perceptive capability of the two eyes, and leads to inconvenience in driving. Testing visual acuity cannot solely determine whether the person is fit for driving because visual acuity generally improves after a cataract surgery (making visibility better).
In a recent study by Curtin-Monash Accident Research Centre (C-MARC), patients having undergone cataract surgery in Shelby Township and in other places have undertaken a contrast sensitivity test along with a visual acuity test in order to fully qualify for driving. To reduce driving difficulty due to contrast sensitivity, C-MARC also plans to perform researches to determine what conditions causes most of these difficulties.
Which patients have greater risks after the surgery?
Elderly patients who undergo cataract surgery are given a minimum gap of 5-7 days, and in case of diabetic patients about 12-15 days between the surgeries of both the eyes .This makes the patients suffer disparity in vision till both their eyes get the surgical procedure done on them. The people who are required to drive during this time are the prime victims of this disparity.
The vision tests for issuing driving licenses to the elderly comprise depth perception, functional field of view, acuity as well as contrast sensitivity. But acuity is given more importance in determining whether the person deserves a driving license or not. But this should not be the case, especially for the patients who have undergone their first cataract surgery and have achieved improved vision in one eye, but are still suffering from cataracts in the other.
Most of the studies that have been done so far on cataract surgery and driving performance have pointed towards making contrast sensitivity a major factor in determining the eligibility of the elderly cataract patients for driving. Especially, patients with bilateral cataracts are at higher risks after surgery. It is recommended that the patients should either get both their eyes operated on dates close together, or that driving licenses should be issued to cataract surgery patients based on tests of contrast sensitivity in the eyes, rather than visual acuity tests.