Aging, cataracts, and their influence in driving
Impairment of accommodation and visual adaptation to changes in light, visual field narrowing, photopic and mesopic visual acuity, dynamic visual acuity, contrast perception, etc., are very serious manifestations that appear during aging and compromise the safety of the older person as a driver or pedestrian.
Visual function is reduced by nearly 25% in the population aged over 65 years as a result of age-related diseases such as arterial hypertension, cataracts, macular degeneration, glaucoma or diabetes.
Information on fatal accidents allows it to be estimated that 50% of traffic accidents involving older drivers are related to vision defects.
Three percent of persons over 60 years and 13% of persons over 65 years have visual field defects, although only 1% has binocular field defects.
The greatest risk of accident related to the visual field is found in binocular field impairments and in diseases associated with pigmentary retinosis and glaucoma.
Diseases of the retina and optic nerve generally affect patients from 20 to 60 years of age.
Cataracts, surgery and aphakia
The risk of collision of vehicles driven by elderly persons is raised even further if these drivers have cataracts impairing their vision, a situation that occurs in over half of adults over 65 years of age.
Developing cataracts often leads to secondary myopia as a result of the change in the eye’s refractive power. These elderly persons begin to be able to read close up and think that their vision has improved.
Drivers who have posterior subcapsular opacifications often complain that they are bothered by the headlights of oncoming vehicles and bright sunlight.
Several studies have shown that cataract surgery reduces the risk of collision in elderly drivers by up to 50%.
Absence of the crystalline lens in the eye causes high hypermetropia and must be corrected with a lens, requiring months for the patient to learn new visual coordination.
Removal of the crystalline lens causes absolute loss of accommodation, a reduced visual field is reduced and post surgical astigmatism.
The introduction of the intraocular lens in modern cataract surgery has greatly reduced the side effects of aphakia or absence of the crystalline lens of the eye.
After surgery, concern is focused on the period of recovery of visual function, the detection of early complications occurring in the first weeks, and the use of glasses correctly adapted to the new situation.
Patients operated on for cataracts with an intraocular lens implant have a small reduction in visual field, which is always less than that caused by a corneal contact lens and much less than the aphakic glasses previously worn by the patient.
With the aging of the population and the search for complete well being, it is increasing common to find drivers who have required cataract surgery.
Refractive surgery
Refractive surgery is a type of surgery performed on the cornea to correct astigmatism, myopia and occasionally hypermetropia.
Modification of the cornea requires a period of adaptation to the new situation because of the memory effect of all living tissues, optical distortions, irregularities in the polished corneal surface, refractive instability, and because the final result of the surgery is still pending.
Tips
- Individual medical advice to protect the vision of patients will be able to improve the global visual capacity of all drivers. Therefore, we will achieve that the elderly keep their safety and independence as drivers.
- The advice to change driving patterns based on the visual function impairment is important taking into account that two thirds of the elderly drivers with visual disorders consider that their vision is “good” to drive.
- When the physician evidences a progressive impairment of visual capacity, it will be advisable that the specialist at the end of the revision issues an updated report to the patient that allows for detecting the actual risk of that person when driving. This report would be critical for obtaining the driving license or its extension.
- After a cataract surgery it is highly useful that the ophthalmologist informs the patient of the complete recovery of his visual capacity for driving.
- The physician should recommend not to drive for six months following refractive surgery, although the patient thinks that his vision is adequate.
- It would be advisable that physicians would recommend our patients to renew their driving license after the ophthalmic surgery, or at least to indicate them that, when they should do it mandatorily because their license is to expire, they inform the accreditation centers of their new situation, for compliance with the terms legally established, for their safety and that of others.