Travelling by buses is the most common and preferred mode of commuting in India which is a developing country. In comparison to other modes of transport it is very economical and availability of frequency of services is quite high and flexibility of time is the common reasons for this becoming better mode of transportation. Buses ply during day and night and so the driving conditions and attitude of the drivers also vary depending upon their duty hours. Vision plays a very important role not only to concentrate on the road ahead and also the various other reflexes needed to control the buses in different situations depends mainly on a normal visual acuity for the safety of passenger and others on the road. Indian roads and highways and the attitude of other vehicle users pose multiple challenges to the drivers of buses. India has 48.65 lakhs km of road network making it the second largest in the world. [1] Transportation of people in India is mainly dependent on roads, carrying almost 80% of its passengers. And due to the increasing number of road rage incidents and misuse of roads such as for cattle rearing, drying of hay in rural setup and children playing on roads along with the poor design and maintenance of roads and poor signalling system in an urban setup are few of the non driver related factors, wherein adequate visual acuity of drivers help in avoiding the mishap. As a developing nation it has a vast and exhaustive network of national highways (NH) connecting various parts of the country. Road traffic accident is a major cause for health hazard worldwide and is a major cause for mortality and morbidity due to the resulting trauma. [2] The drivers are not only more vulnerable for highway mishaps but within city limits also. Visual disability among drivers is one of the major causes of road accidents in India. Over half of the Indian drivers responsible for road accidents have at least one visual disability, according to a study by the Indian Institute of Sciences (IISc) [3]. This study mainly focuses on the visual functions of drivers as vision is the most important source of information during driving and many driving related injuries have been associated with visual problems.

A screening camp was conducted during the month of April in the year 2019 for a period of 7 days exclusively for bus drivers to check for any visual disorders in the bus stand in Poonamallee located in NH 4 (Chennai - Bangalore highway) frequented by bus drivers from all parts of Tamil Nadu, Karnataka and Andhra Pradesh, as it is a highly traversed route connecting two busy Metropolitan cities of South India; moreover this road connects other important places like Kanchipuram, Tiruvannamalai, Ambur, Vellore etc. for various reasons. This was a cross sectional, non comparative type of study. These drivers were tested for visual acuity and colour vision and visual field by confrontation method at the camp site. Those suspected of having visual problems were sent for detailed check up at Saveetha Medical College and Hospital. Comprehensive eye examination at the base hospital included Visual Acuity using Snellen’s chart, Refraction, Direct Ophthalmoscopy, Tonometry, Slit Lamp Biomicroscopy and Automated Perimetry. Detailed examination was done to exclude cataract, glaucoma, ARMD and retinopathy due to different causes. All drivers with uncorrected refractive error were given suitable spectacles. Anti-glaucoma medications were prescribed and advised for a regular follow up for those diagnosed with glaucoma. The results were tabulated and evaluated.

Criteria for visual standard is in accordance to International Council of Ophthalmology (ICO) 30th World Ophthalmology Congress, Brazil, 2006(4). Totally 300 drivers were examined. The mean age of drivers was 44 years (range 18- 70 years).

Pie Chart 1 shows the age wise distribution of drivers.

Of the drivers who participated in study 46(15.3%) have studied until primary school, 118(39.3%) Middle School and 136(45.4%) have completed high school till undergraduate level.

About 214 (71%) drivers were emmetropic and the remaining 66 (22%) drivers had visual acuity less than 20/20. 20 drivers that are nearly 6% had visual acuity less than 20/30 making them unfit for driving. 71% of drivers were fit for driving and 22% of drivers had mild visual impairment. Severe visual impairment was found in (20) 7% of the drivers.

Vision is the most important source of information during driving and driving related injuries have been associated with visual problems. Therefore, visual assessment of drivers is a major health issue. [5] In a recent study done at Guwahati, India (Chauhan S). [6] an attempt was made to identify the shortcomings in physical attributes of the drivers that may pose road safety hazards such as visual acuity, field of vision, depth perception, glare recovery, colour vision, contrast sensitivity, phorias, etc.

In our study we found that 214(71%) drivers were emmetropic and were fit for driving. The remaining 86(29%) had visual impairment of some sort or the other. This is quiet a large magnitude to be accepted. A similar study conducted by Verma R et al [7] showed the prevalence of refractive error to be 18.82%. Another study conducted by Dr. Vikas Mahatme et al(8) in Nagpur had similar result as ours with 33% refractive error. Commercial vehicle drivers in the Central Region of Ghana had 20.4% refractive error.(9)in our study 108(36%) of drivers were wearing spectacles while 192(64%) were neither wearing spectacles nor did they visit the Ophthalmologist in the past.

Cataracts, diabetic retinopathy, glaucoma, and macular degeneration may weaken colour perception, contrast sensitivity, depth perception, glare recovery, or peripheral vision components. Ultimately, these vision impairments elevate the risks of traffic collisions and violations. [16]

Surprisingly all were unaware of such defect existing in them and had never faced any problem due to that. A direct link between increased risk of road traffic accident and colour vision defect has not been established. [17] In some circumstances it may impact performance of interpreting traffic control devices and other colour coded signals if other cues (luminance, position, pattern) are not sufficiently informative. [18]

This highlights the lack of concern and insensitivity of drivers towards visual health and at the same time points out the fault in our licence issuing system. Driver education is not mandatory and physical fitness of candidates with respect to visual abilities is not evaluated before issuing driver licence. Only the manoeuvring abilities of drivers during day time are considered sufficient for issuing the licence. These defects should be rectified for safety on the roads. Driving is a privilege and not a right and that the primary responsibility of those who assess potential drivers is to the public and not to the applicant.

Vision is the most important source of information during driving and many driving related injuries have been associated with visual problems. Prevalence of visual impairment among drivers is very high and poses serious health and social issues. As majority of the drivers did not have ocular examination at the time they were issued driving licence, ocular examination by an Ophthalmologist should be introduced as part of the compulsory test process for issuing and renewing drivers’ license. This could ascertain minimum visual requirement for driving and will help to reduce the incidence of road traffic accidents.