When we speak about road accident, we are actually talking about three key elements of road accidents namely road user, vehicle and road condition.
The most important element in all three is the human as a road user and also as a driver. Driver quality becomes the main focus in each discussion on road problem.
It is quite hard to increase road user quality without awareness and sense of responsibility. This is because as bad as car’s condition can be it is still cannot move by its own to be involved in an accident.
Road condition also plays a role. A zigzagging road is more dangerous than straight road while road width can provide comfort for the users. Good road signs and road chicane could also help.
Environmental factors such as rain, slippery road, fog or hot weather also cannot be denied contributed to road accidents.
Driving and vision
When driving, vision and oculomotor (movement – vision) reaction relationship becomes very important. Reactions like braking, taking a curve or avoiding obstacles is one of oculomotor reaction.
Here we could sum up clearly that in driving process, eye and vision condition are very important. This aspect is seldom discussed in cases of road accidents.
Because there is a clear association between road safety and eye vision, then eye vision factor must be given attention. Visual acuity test which done during driving license application is too simple and does not follow the standard that it should be.
It is not only done roughly but it is done by people with less expertise on vision and human eye.
One who can read vehicle’s plate number at the distance of six meters is does not mean that he or she have good vision. This is because visual acuity test is one of eyesight function test.
When a driver drive vehicle, the total eyesight function should function normally. This is to ensure oculomotor reflex functioning well and quick mainly in aspect of visual acuity, contrast sensitivity, color perception and stereoscopic eye vision area.
Limited area of visual field can be disturbing because when driving, peripheral vision (side vision of the eye) would be vital to determine vehicle position with other vehicle. Therefore driver knows where he is especially when overtaking, changing lanes and taking bend. Vehicle speed is also observed by using peripheral vision.
Interference in visual field will result driver become unnoticed of object beside of the vehicle and this condition can happen in retinal damage cases like Glaucoma’s patient, diabetes or retinal detachment.
Eye Test and Road Safety
Color test is also important to facilitate driver in identifying color code in road marking, for example red color for dangerous areas, yellow for more caution and green or blue for safe area.
Stereopsis test also should be done to ensure three dimensions vision (3D) is well-enough for the driver. It is important to estimate vehicle distance with objects ahead while driving. Of people with squinted eye, 3D’s vision lessens depending on the squint level.
If a driver having squint problem in a tired body’s condition especially when coming back from far work place or on long journey, the driver can have diplopia (object seem as two), glare and can get drowsy quickly.
Diplopia could lead to accidents because driver would become confused when seeing two overlapping images.
Good visual acuity level is at levels 6/9 in Snellen’s chart for each eye separately with vision aid such as eye glass or contact lens. 6/9 vision means one who has vision problem had to stand up at the six meters distance whereas normal people can see clearly at nine meters distance.
Examples of Situation
Try to imagine one who have just 6/18 level of eyesight in Snellen’s chart drive a vehicle. Those people having normal vision already clearly see object well off 18 meters before whereas these drivers will merely see clearly that object at the distance six metres.
Let say that a cat crossing 30 meters ahead while driver speed at 80 kilometers per hour (km/h). At that speed, the driver will only take 17 seconds to reach to the cat.
If the driver only can see the cat at six meters distance, can he brake his vehicle or avoid in time because he only have about three seconds to act within six meters whereas braking time take more than 3 seconds to stop from speed 80 km/h.
Contrast between object with background is also important while driving especially when raining or driving at night. Imagine when you drive at dusk, suddenly a buffalo crosses the road. You are difficult to see the buffalo in the dusk because the contrast between buffalo and dusk environment causing you difficult to see the buffalo although the buffalo is big. Good contrast enable driver see an object easily. So contrast sensitivity test also should be carried out when getting driving license.
The public vehicle driver especially, must undergo thorough eye examination and periodically to determine perfect level of eyesight function. This is because accident which involves public transport such as bus would involve many injuries or loss of lives.
Effects of Interrupted Eye Vision
Interference in eyesight function would also raise symptoms such as dizziness, quickly become drowsy, seeing glares or tired eye which all can cause loss of focus and discomfort when driving.
Because more than 90 percent case of road accidents are involving human factor, then all possibilities that became the cause of accident should be given attention.
Among factors that involve vision and road safety question includes visual impairment problems such as myopia, long-sighted, Astigmatism, color blind and others.
A strict condition to ensure all drivers have suitable level of eyesight is needed for safeguarding safety during in road.
Apart from the sense of responsibility before and while driving and complying with all road signals, attention to eye vision factors especially during license test and driving in road may also avoid tragedies that can rob lives. Photo attribution to kyknoord.Sponsored links: