|Year : 2021 | Volume
| Issue : 2 | Page : 63-66
Visual examination standard for forklift and crane operators: A report for 66 operators of a factory in Mumbai
Prema K Chande1, Kalika L Bandamwar2
1 Lotus College of Optometry, Mumbai, Maharashtra, India
2 Chitkara School of Health Sciences, Chitkara University, Punjab, India
|Date of Submission||27-May-2019|
|Date of Acceptance||20-Jan-2020|
|Date of Web Publication||9-Jul-2021|
Ms. Prema K Chande
Lotus College of Optometry, Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
Context: Forklift and crane industry in India is progressing at a rapid pace and the visual integrity of the operators is crucial for occupational safety. Hence, we performed a vision screening at a factory based in Mumbai. Aims: To evaluate the current visual status of forklift and crane operators working at a factory in Mumbai. Settings and Design: Prospective observational cross-sectional. Methods and Materials: All forklift and crane operators were invited to undertake visual examination that included visual acuity (VA) assessment, refraction, slit-lamp examination, color vision assessment, visual field assessment, and stereopsis. Referrals were made for participants who needed further assessment. Statistical analysis used: Mean and standard deviation were calculated and presented. Results: A total of 66 forklift operators with an average age of 48 years that ranged from 26–60 years completed the study. The average distance VA in LogMAR with current spectacles was 0.1 ± 0.14. The near VA with usual spectacles averaged at 0.63 M ± 0.2 M. The best-corrected VA (BCVA) of 0 LogMAR was not achieved by 12% subjects; however, all participants except one met the 0.3 LogMAR visual acuity criteria. The average stereopsis was 55.8 ± 47.8 with 8% operators had lower than acceptable levels of stereopsis while 7% could not meet the set criteria. One operator had 400 s of an arc and 4 had 100 s of arc stereopsis. Conclusions: The study demonstrates an urgent need to set up standards for vision assessment at the time of employment and frequency of eye examination for forklift and other powered industrial vehicles.
Keywords: Contrast sensitivity, depth perception, forklift operators, vision
|How to cite this article:|
Chande PK, Bandamwar KL. Visual examination standard for forklift and crane operators: A report for 66 operators of a factory in Mumbai. Indian J Occup Environ Med 2021;25:63-6
|How to cite this URL:|
Chande PK, Bandamwar KL. Visual examination standard for forklift and crane operators: A report for 66 operators of a factory in Mumbai. Indian J Occup Environ Med [serial online] 2021 [cited 2021 Jul 27];25:63-6. Available from: https://www.ijoem.com/text.asp?2021/25/2/63/321070
| Introduction|| |
The ability to safely and accurately operate heavy-duty machines such as forklifts or cranes requires good vision and hand-eye coordination. Vision plays a crucial role to enable the operators to safely use their equipment. Every day thousands of people experience work injuries in India and many are victims of injuries related to heavy machines., Some of them may result in a permanent or temporary disability. While a large proportion of the injuries could arguably occur due to accidents resulted from the complexity of tasks, many could be attributed to the visual inefficiency of the employee. Ideally, regular vision assessments should be conducted to ensure that workers possess the minimum level of visual functioning needed to accomplish visual tasks and that the potential hazards are identified. Precautionary measures would be to conduct the vision assessment prior to the employment which will ensure that the visual demand of the job matches the visual ability of the employee. A regular vision assessment thereafter would help monitor any changes that need attention.
The India Forklift Market Overview (IFMO) 2016–2022, claims that there is the gradual growth of the use of forklifts in the Indian industry. Industries such as automobiles, logistics, chemicals, pharmaceuticals, construction, and so on are growing in the Indian markets and they contribute to the majority share of forklift applications. The forklift operators are skilled labor and need certain licensing to perform their duties. In the absence of Indian guidelines for forklift operator's eligibility, we understand that the guidelines published by the Occupational Safety and Health Association (OSHA), USA are followed by forklift training academies in India. OSHA had published revised guidelines in the year 2015. These include aspects of operator training, retraining, hands-on driving, and evaluations on a regular basis. The inspection checklist also includes a safety checklist for the forklift itself like a seat belt, the functioning of the motors, and so on. The guideline does specify that the eye examination is mandatory; however, there are no further details provided on what aspects of the visual system needs to be assessed and what level of ocular disability is acceptable.
Overall the occupational fitness requirement guideline in India does not include details of vision assessment. We did a free internet search and to our disappointment did not find inclusion in vision testing in any of the Indian occupational fitness guidelines for forklift operators. The only mandatory documents that suggested vision assessment and fitness are required were found by the Atomic Energy Regulatory Board (AERB) for their employees. These guidelines suggest assessment of visual acuity, stereopsis, visual fields, and color vision as mandatory factors. However, even these fail to specify the cutoff values. Under these circumstances, the decision for certifying someone fit for their job is rendered to the understanding of the clinician of the visual demands or to the training organizer's understanding of the vision assessment. It would be ideal if clinicians and industry personnel came together and determined the visual requirement guidelines to ensure the safety of the forklift operators and others working around them.
To understand the visual status of forklift operators in India, we conducted a vision screening for forklift operators of a chemical manufacturing unit to recommend their visual fitness for the job. This report presents a snapshot of the visual assessment of forklift and crane operators of an industrial setup based out of Mumbai.
| Subjects and Methods|| |
Based on the recommendations of the AERB, a vision examination protocol was developed. All forklift operators working at the factory were required to register for the vision assessment. Post-registration, a trained optometrist obtained relevant medical history about systemic and ocular health. The tests included measurement of how well the operators could see at a distance which was measured using the standard logMAR chart (Low Vision Resource Centre, Hong Kong) that was presented at 4 m distance, for each eye separately (monocular) and then together (binocular). While perception of depth, otherwise known as stereopsis was assessed using Titmus-fly test (Precision vision, USA), evaluation of color vision and measurement of visual fields was done using the Ishihara color vision tests (24-plate by Good-Lite, USA), and the tangent screen (Low Vision Resource Centre, Hong Kong), respectively. Along with these, we performed refraction to determine the requirement for spectacle correction. Anterior segment evaluation was done using torchlight and pupillary reactions were observed and recorded. Undilated posterior segment evaluation was done with the help of direct ophthalmoscopy (Keeler, UK) and intraocular pressure (IOP) was assessed using Keeler PulseAirTM tonometer (Keeler, UK).
Monocular best-corrected distance visual acuity of 0.3 LogMAR was considered the minimum standard for an acceptable vision for the operators.
Stereopsis measured with the help of the Titmus fly test of Randolt dots is measured in seconds of an arc. The higher the value the poorer is the depth of perception. A smaller value indicated good binocular stereopsis. Stereopsis of 80 s of an arc was considered the cut off for acceptable level of depth perception.
Visual field was recorded in 10 meridians that included four superior and 6 inferior meridians for 10°, 15°, 20°, 25°, 30°, respectively. If all 50 points (5 points × 10 meridians) were visible with the smallest target size, the visual field was considered normal. However, if the forklift operator failed to see more than 5% points (10% loss) or was not cooperative he was referred to automated perimetry.
The study had obtained Ethical clearance from Institutional Review Board of Lotus College of Optometry, Mumbai. Permission to organize an eye examination was obtained from the Occupational medicine and health center of the factory and all forklift operators provided oral consent to participate for the eye examination protocol at their place of work.
| Results|| |
A total of 66 forklift operators completed the visual examination protocol. They were all males and their ages ranged from 26 to 60 years with average at 48.1 years. The average distance visual acuity in LogMAR with current spectacles was 0.1 ± 0.14. The near visual acuity with usual spectacle correction averaged at 0.63 M with a standard deviation of 0.2 M. The BCVA of 0 LogMAR was not achieved by 12% subjects, however, all participants except one met the 0.3 LogMAR visual acuity criteria. The average stereopsis was 55.8 ± 47.8. About 8% (n = 5) operators had lower than acceptable levels of stereopsis while 7% (n = 4) could not meet the criteria set for visual fields. One operator had 400 s of an arc and 4 had 100 seconds of an arc. The average IOP was recorded at 16 mmHg ± 6.5 mmHg. Of this 7% were identified as glaucoma suspects based on visual filed changes and increased IOP. Of all there was one person was found to have a cataract, these operators were referred for further evaluation. Results are as shown in [Table 1] below.
| Discussion|| |
Appreciation of depth is an important aspect to perform everyday tasks. The three-dimensional understanding of the relative location of objects could also be done with the help of monocular cues (e.g., shadows, relative size, motion, parallax, etc); however, it does not eliminate the chances of misinterpreting the distances between objects. Hence, it is important that stereopsis is assessed, and acceptable levels determined for critical jobs, especially when there is an indication of high-risk environment e.g. use of forklifts in industrial areas and construction sites. The normal value for stereopsis is 40 s of an arc. American Optometry Association's Occupational standard states that a minimum 80 s of an arc is needed for forklift operators (Good et al., 1996). The average stereopsis found in the study population was 56 s of an arc with one operator not having the said acceptable levels.
When it comes to safety of workers, the field of view is as important as the stereopsis. It enables the forklift operator to be awake of his surroundings. Forklifts are commonly used as busy crowded work sites that are usually filled with other workers and sometimes even public. While forklifts lift heavy and oversized items, lack of awareness of the surrounding can lead to accidental collision with other objects and more critically with people. Saric et al. in their study on analysis of forklift accident trends within the Victorian industry (Australia) in 2013 concluded that 50% of the accidents were due to collision. The consequences of which could only be dangerous. Sometimes forklift has a load that blocks the view in the front, the operator has the facility to partially turn in the seat and then drive backward, this, in turn, limits the lateral extent of vision on the side of the head facing the new direction of travel. The standards are set at a minimum of 70° of the horizontal visual field on either side of the target fixated. While a normal visual field assessment is a good clinical criterion to ensure the visual fitness of the forklift operators.
Bureau of Labor Statistics data identifies approximately 6,820 occupational injuries involving forklifts. Of these injuries, 4,320 occurred in the manufacturing industry. The total deaths reported were 4,585, of which 70 were due to forklifts. Green et al. (2013) in their study demonstrated concluded on significant associations between visual, hearing, and dual sensory impairments and history of motor vehicle collision involvement of older drivers.
Collin et al. in 1999 recommended that requirements for becoming a skilled and qualified operator of a powered industrial vehicle include meeting physical requirements for vision, hearing, and coordination to reduce injuries related to forklift operators. The above recommendation was for operators who have a normal visual field therefore, the ones with affected visual fields are likely to face more difficulty.
In the absence of guidelines that are approved and prepared in collaborations of employers and vision care providers, people with defective eyesight can perform complicated and sometimes dangerous tasks. It would be mutually benefitted to both employees and employers to set visual demands to ensure that the right people with the right vision are performing tasks. This would help reduce the overall risk of unwanted accidents and losses related to it. Accidents typically result from uncorrected visual defects affecting safety and productivity. The workers identified to have not met the visual demands can be transferred to another task for which they are visually capable to perform efficiently.
There is additional value for the measurement of visual assessment on a regular basis. The recording of visual details at the beginning of employment provides the basis for evaluating problems which may have rose later as a result of a work-related injury.
Any physical fitness standards including vision standards are set to match the requirements of the jobs to help ensure that the workers have the necessary visual characteristics to achieve the requirement of the tasks safely and efficiently. In the work environment, vision standards should be viewed as guidelines, not as absolute limits. All jobs make varying demands on eyesight and it is essential that each worker should possess an adequate vision for the work he is required to undertake. Some work requires the highest visual standards whereas other jobs can be performed adequately by persons with substandard vision.
Sadly, the scenario in India is different from other parts of the world. We profoundly found the lack of guidelines for eligibility that includes a vision assessment and details on what aspects of vision should be tested, using what type of tests and how frequently should this be done. Further frustration comes when we observe a certain guideline that has included a vision assessment only to disappoint us with a lack of cutoff values. Leaving the decision to eye care practitioner to certify someone fit for the job and the employer to accept or not accept a certain employee for the job, both not fully understanding the relative connection between job requirements and ability of the visual system to deliver it. Most often, when an individual fails to meet a vision standard, a change in refractive correction is all that is required. A right lens is often all that is necessary for the worker to regain lost efficiency.
The visual acuity standard should not be arbitrarily set to be overly restrictive. The size of visual details, working distances, need for speed and accuracy, and the consequences of error should be assessed and evaluated before setting the visual acuity standard. In our study we understand that the color vision is not a critical visual aspect for the forklift operators hence, it would have been okay for someone to have color vision deficiency of a type and is still safely able to operate lifts. Having said that, if the forklifts had a CCTV attachment and a screen to help them with a better view of their surroundings and if such a system indicates the proximity of another object in the vicinity by changing a particular symbol's color, in that case, the color vision would also have been critically important.
| Conclusion|| |
The study demonstrates an urgent need to set standards for vision assessment at the time of employment and frequency of eye examination for forklift and other powered industrial vehicles. It further suggests that CCTV attachments to forklifts would improve safety and reduce occupational accidents.
We are grateful to the interns from Lotus school of Optometry who assisted with data collection.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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