Relationship between Functional Visual Acuity and Useful Field of View in Elderly Drivers

Clinical Results and Factors Affecting Visual Function in Eyes Implanted with an Enhanced Monofocal Intraocular Lens

Purpose

To compare the clinical results achieved with the enhanced monofocal intraocular lenses (IOLs) with those of the monofocal IOL and investigate factors affecting the distance, intermediate, and near vision.

Patients and Methods

Patients were included who underwent bilateral consecutive cataract surgeries using the same IOLs with follow-up to 1 month postoperatively. Refractions, monocular UDVA and CDVA, and binocular distance-corrected functional visual acuity at 5 meters (BDCFVA), at 66 centimeters (BDCIFVA) and at 40 centimeters (DCNVA) were assessed. Multiple regression analysis was used to assess the factors affecting binocular BDCFVA, BDCIFVA, and BDCNFVA. Subjective symptoms were assessed using the Near Activity Visual Questionnaire (NAVQ) and visual analogue scale (VAS).

Results

Sixty patients (120 eyes) implanted with the Tecnis Eyhance IOL (30 patients, 60 eyes) or the Tecnis monofocal IOL (30 patients, 60 eyes) were included. The Tecnis Eyhance IOL provided significantly better binocular BDCIFVA than the Tecnis monofocal IOL in patients under 70 years of age. Multiple regression analysis showed that age was the only factor affecting distance and intermediate visual function in eyes with the Tecnis Eyhance IOL; gender, pupillary diameter, axial length, and average keratometry were not significant. There were no significant differences in subjective symptoms.

Conclusion

The comprehensive cohort analysis did not confirm the advantage on the intermediate vision of the Tecnis Eyhance IOL. Younger age may be an important factor to benefit from the unique optical characteristics of this IOL.

Functional visual acuity after implantation of diffractive extended depth-of-focus intraocular lenses using an echelett optics

Background

The prospective comparative case series aimed to evaluate all-distance visual acuity, contrast sensitivity, and functional visual acuity (FVA) of eyes with diffractive extended depth-of-focus (EDOF) intraocular lenses (IOLs) using an echelett optics and monofocal IOLs with the same platform.

Methods

Diffractive EDOF and monofocal IOLs were implanted in 27 eyes of 27 patients each. At 3 months after implantation, all-distance visual acuities at distances of 0.3, 0.5, 0.7, 1, 2, 3, and 5 m were measured under distance-corrected. Static visual function was also examined using photopic contrast sensitivity and area under the logarithmic contrast sensitivity function (AULCSF). Dynamic visual function was examined with FVA, and mean FVA value, visual maintenance ratio (VMR), mean response time, and number of blinks were evaluated. These outcomes were compared between the two IOLs.

Results

The mean distance-corrected visual acuities were better at distances of 0.7 m or nearer in eyes with EDOF IOLs. There was no difference in the contrast sensitivities (P > 0.22). In the FVA results, no difference was found in mean FVA and VMR (P > 0.68).

Conclusion

The static and dynamic evaluations of postoperative visual functions demonstrated that the visual function of eyes with EDOF IOLs under photopic and distance-corrected conditions was comparable to eyes with monofocal IOLs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-02189-7.

Regional Gray Matter Volume Identifies High Risk of Unsafe Driving in Healthy Older People

In developed countries, the number of traffic accidents caused by older drivers is increasing. Approximately half of the older drivers who cause fatal accidents are cognitively normal. Thus, it is important to identify older drivers who are cognitively normal but at high risk of causing fatal traffic accidents. However, no standardized method for assessing the driving ability of older drivers has been established. We aimed to establish an objective assessment of driving ability and to clarify the neural basis of unsafe driving in healthy older people. We enrolled 32 healthy older individuals aged over 65 years and classified unsafe drivers using an on-road driving test. We then utilized a machine learning approach to distinguish unsafe drivers from safe drivers based on clinical features and gray matter volume data. Twenty-one participants were classified as safe drivers and 11 participants as unsafe drivers. A linear support vector machine classifier successfully distinguished unsafe drivers from safe drivers with 87.5% accuracy (sensitivity of 63.6% and specificity of 100%). Five parameters (age and gray matter volume in four cortical regions, including the left superior part of the precentral sulcus, the left sulcus intermedius primus [of Jensen], the right orbital part of the inferior frontal gyrus, and the right superior frontal sulcus), were consistently selected as features for the final classification model. Our findings indicate that the cortical regions implicated in voluntary orienting of attention, decision making, and working memory may constitute the essential neural basis of driving behavior.

The negative effects of dry eye disease on quality of life and visual function

In recent years, dry eye has become a hot topic within ophthalmology and optometry, especially in regards to new frontiers in treatment modalities which include novel devices, procedures, and medications. However, some of the more understudied areas in dry eye involve its impact on quality of life. Although ocular discomfort symptoms are well known to be associated with dry eye, its negative effects on visual function remain underrecognized. This paper reviews these topics within the currently published literature to heighten awareness among clinicians. Key Words: D ry eye, quality of life, visual function, functional visual acuity, patient questionnaire, OSDI, SPEED, SANDE, IDEEL, NEI VFQ-25

Factors affecting depth perception and comparison of depth perception measured by the three-rods test in monocular and binocular vision

Purpose

The purpose of this study was to explore the effects of factors affecting depth perception of moving objects using a modified three-rods test, which can be used at longer distances than the conventional one, and to compare differences in the results between binocular and monocular vision.

Methods

This study included 24 volunteers (10 women, 14 men; mean age, 35.2 years; standard deviation, 6.8 years; range, 22–56 years). We measured depth perception using a modified three-rods test under eight different conditions and investigated the factors affecting depth perception using a linear-effect model.

Results

The results identified test distance, binocularity, masking, and direction of movement as significant factors affecting depth perception of a moving object.

Conclusions

The current study successfully determined factors affecting depth perception using the three-rods test with a moving object and the results should contribute to further clinical and social applications of the three-rods test.

Machine-learning approach to predict on-road driving ability in healthy older people

AIM

In Japan, fatal traffic accidents due to older drivers are on the rise. Considering that approximately half the older drivers who have caused fatal accidents are cognitively normal healthy people, it has been required to detect older drivers who are cognitively normal but at high risk of having fatal traffic accidents. However, a standardized method for assessing the driving ability of older drivers has not yet been established. We thus aimed to identify a new sensing method for the evaluation of the on-road driving ability of healthy older people on the basis of vehicle behaviors.

METHODS

We enrolled 33 healthy older individuals aged over 65 years and utilized a machine-learning approach to dissociate unsafe drivers from safe drivers based on cognitive assessments and a functional visual acuity test.

RESULTS

The linear support vector machine classifier successfully dissociated unsafe drivers from safe drivers with accuracy of 84.8% (sensitivity of 66.7% and specificity of 95.2%). Five clinical parameters, namely age, the first trial of the Rey Auditory Verbal Learning Test immediate recall, the delayed recall of the Rey-Osterrieth Complex Figure Test, the result of the free-drawn Clock Drawing Test, and maximal visual acuity, were consistently selected as essential features for the best classification model.

CONCLUSION

Our findings improve our understanding of clinical risk factors leading to unsafe driving and may provide insight into a new intervention that prevents fatal traffic accidents caused by healthy older people.

Relationship between visual function and cognitive function in the elderly: A cross-sectional observational study

It has been suggested that functional visual acuity (VA) testing may be able to measure both the visual performance and cognitive ability needed for driving and help to reduce the number of road traffic accidents. The aim of this study was to investigate the relationship between visual ability and cognitive function in healthy elderly subjects. The study included 34 eyes with a decimal best-corrected visual acuity (VA) ≥1.0 in 34 subjects (16 men, 18 women; mean age 72.7 ± 6.1 [range, 61-83] years) with the same type of monofocal intraocular lens implant. Using the score on the Japanese version of the Mini-Mental State Examination (MMSE) questionnaire, the subjects were divided into a mild cognitive impairment (MCI) group (score <28) and a normal cognition (NC) group (score ≥28). Visual ability was evaluated by functional VA testing. Functional VA was significantly lower in the MCI group (n = 10) than in the NC group (n = 24; P<0.02). There was no significant difference in best-corrected VA between the two groups. High correlations were found between the MMSE score and the logMAR functional VA (r = -0.36, P = 0.04), standard deviation of functional VA (r = -0.39, P = 0.02), and the visual maintenance ratio (r = 0.34, P = 0.048). In summary, despite a good best-corrected VA, deterioration in visual ability was detected in elderly individuals with MCI when measured by the functional VA test. Functional VA could be used to evaluate the integrated visual ability associated with age-related cognitive decline and have applications that help to reduce the disproportionately high rate of road traffic accidents in the elderly.

Are Your Eyes "on the Road"? Findings from the 2019 National Study on Vision and Driving Safety in Spain

Background: Vision is an undisputable contributor to the explanation of many human-factor related traffic crashes happening every day. The Inland Transport Committee (ITC), the United Nations regulatory platform, included on 1st April 2020 special action on the vision of road users inside the ITC Recommendations for Enhancing Road Safety Systems. The results of this wide-scale study on drivers’ vision health conducted in Spain perfectly illustrates the need of global action and its potential impact on the public health figures and the burden of potentially preventable traffic causalities. Objective: The aim of this study was to assess three key visual health issues (i.e., visual acuity, visual field campimetry and glare recovery) among Spanish drivers, in order to formulate implications and possible guidelines to enhance road safety. Methods: This cross-sectional study examined the visual health of a representative sample of 3249 drivers (70% females and 30% males) with a mean age of 41 (SD = 13) years, gathered from all the 17 autonomous communities of Spain. Results: The tests performed allowed to determine that 15% of Spanish drivers have a poor photopic vision, while 38% of them present an inadequate mesopic vision. Further, 23% of drivers have deficiencies in peripheric visual field campimetry, and the average time for full-vision recovery after a 10-s glare was 27 s. Sex, age and driver type (professional vs. non-professional) differences were found for the study variables. Conclusions: The findings of this study support the idea that certain demographic-based population groups of drivers present several unaddressed deficiencies and impairments in visual health. Overall an estimated 29.5% of Spanish drivers present visual issues, that need to be attended in order to enhance the prevention of driving crashes and the road safety of all road users.

Kinetic visual acuity is correlated with functional visual acuity at higher speeds

Objective

To measure the kinetic visual acuity (KVA) which is the ability to identify approaching objects and the functional visual acuity (FVA) which is continuous VA during 1 min under binocular and monocular condition (non-dominant eye shielding) for healthy subjects, and related ocular parameters to explore their correlation and implication in aspect of integrated visual function.

Methods

The mean age of the 28 participants was 38.6±8.9 years (range, 23–57 years; 6 women). A KVA metre (AS-4Fα) and FVA metre (AS-28) were used to measure KVA and FVA, respectively. Multiple regression analysis was conducted to explore correlations among the measured visual function and related parameters, including age, binocularity, best-corrected visual acuity, refraction and tear break-up time.

Results

The results of binocular KVA were better than monocular KVA at all speeds. A strong correlation was found between monocular and binocular KVA. The results of binocular FVA were better than monocular FVA (p<0.001) and there was a correlation between monocular and binocular FVA (R=0.638, p<0.001), as well as the maintenance rate for FVA (R=0.228, p=0.003). A linear mixed-effects model revealed that binocularity for KVA prediction was significant at all speeds and FVA was also significant at 60 km/h (p<0.05).

Conclusion

The current results suggest that both binocularity and FVA may contribute to KVA.

Trial registration number

UMIN00032385

Shortened Measurement Time of Functional Visual Acuity for Screening Visual Function

The functional visual acuity test which is the average of the visual acuities measured during a specific time frame (standard, 60 seconds) has been used recently to assess the visual function in various conditions. The availability of a shorter version of the functional visual acuity test promises to be patient friendly in that it is a simple screening test performed in a shorter period of time than the standard test. The results of measurements of the FVA test between the 30-second measurement time (short-version FVA test) and the standard 60-second measurement are compared, and the feasibility of the short-version FVA test instead of the standard FVA test is investigated. Twenty-eight healthy volunteers (25 men and 3 women) were enrolled in this prospective observational study. All subjects underwent measurement of the binocular distance-corrected visual acuity and the binocular distance-corrected FVA with the 60-second and 30-second measurement times. The interchangeability of the corrected-distance FVA, maximal VA, visual maintenance ratio, and average response time in the short-version and the standard FVA tests was evaluated using the Bland–Altman method, and the results showed agreements of the two tests except for the minimal VA. The short-version FVA test is equivalent to the standard method except for evaluating the visual acuity fluctuations and promises to be a simple visual screening test that can be performed in a shorter time.

Functional Visual Acuity

Dry eye (DE) causes irregularity of the ocular surface and reduces the quality of vision. An intact, regular tear film is essential for high-quality retinal images; however, visual tasks requiring sustained gazing can disrupt the tear film, eventually degrading visual function. A functional visual acuity (FVA) measurement system has been uniquely developed in Japan to evaluate visual function related to tear stability in patients with DE. FVA has been shown to correlate with optical quality. The system measures the change in visual acuity (VA) over time automatically in aqueous-deficient DE and short tear breakup tear film DE characterized by decreased tear stability and minimal epithelial damage. It is also useful to detect minimal visual deterioration correlated with minimal ocular surface abnormality and vision-related quality of life otherwise undetectable by conventional VA testing, to assess and quantify vision-related symptomatology, and to determine the efficacy of treatments for DE disease. Recently, its use has been expanded, such as for the analysis of visual function accompanying refractive surgery, contact lens, cataract and cataract-related disease, retinal disease, glaucoma, amblyopia, presbyopia, and vehicle driving. Its use has revealed that FVA reflects not only visual function related to tear dynamics, but also visual function related to quick recognition of the target. This simple, noninvasive, and sensitive FVA measurement system may be expected to be used worldwide.

Three-rods test as drivers' license vision test from the viewpoint of reproducibility, eye deviation, and functional visual acuity

Background

Three-rods test is required as depth perception vision test to obtain motor vehicle license to drive taxies, buses, and trucks in Japan. Functional visual acuity is measured automatically by successive visual target presentation in a fixed period of time. This study examined three-rods test from the viewpoint of reproducibility, eye deviation, and functional visual acuity to assess the feasibility for drivers' license vision test.

Methods

At three-rods test, a central rod was moved at the speed of 50 mm/sec forward and backward automatically against two fixed rods on both sides inside an illuminated box. An examinee at the distance of 2.5 m observed the rods inside the box from a small window and pushed a button to stop the central rod in alignment with the fixed rods. Erred distance of the central rod from the fixed rods as a mean of 4 measurements was used. At functional visual acuity test, an examinee moved a joystick to the same direction as Landolt-C opening as a visual target which was sequentially presented every 2 seconds for 30 times in 1 minute.

Results

The mean erred distance of three-rods test was reproducible between two tests done on separate occasions (n = 44, ρ = 0.679, P < 0.0001, Spearman rank correlation). Exophoria induced by wearing 4-prism-diopter base-out prism did not significantly influence the mean erred distance while vertical diplopia induced by wearing 4-prism-diopter base-up prism disrupted the measurement (n = 9). The mean erred distance of three-rods test was better correlated with functional visual acuity tested with both eyes open than with conventional visual acuity with both eyes open (n = 17, ρ = 0.2 versus ρ = 0.179).

Conclusion

In the context of the small sample size in the present study, the three-rods test was reproducible, and testable in the presence of phoria, but not testable in diplopia, indicating the feasibility as a depth perception vision test.

Useful field of view test performance throughout adulthood in subjects without ocular disorders

Previous research has shown an age-related decline in Useful Field of View (UFOV) test performance, which measures the duration required to extract relevant information from a scene in three subtasks. However, these results are mostly based on data that may have been confounded by (age-related) ocular diseases. We examined UFOV performance in subjects aged 19.5 to 70.3 years to investigate how UFOV performance changes throughout adulthood. All subjects underwent a thorough ophthalmological examination to exclude ocular disorders. We also examined some elementary visual functions, i.e., near and far visual acuity, crowding and contrast sensitivity. We investigated whether these functions were related to age and whether they could explain a possible age-related decline in UFOV performance. The subjects (n = 41) performed very well on almost every measure and reached far better UFOV and visual acuity scores than those reported by other studies that relied on self-reported absence of ocular pathology. We did not find significant relationships between age and any of the elementary visual functions or the first two UFOV subtasks (R2UFOV1 = 0.03, p = 0.25; R2UFOV2 = 0.07, p = 0.10). However, we found an age-related decline in performance on the third UFOV subtask (R2UFOV3 = 0.36, p < 0.001), which was unrelated to performance on the elementary visual function tasks. Our results show that performance on the first two UFOV subtasks as well as central elementary visual functions may remain high in the absence of obvious ophthalmological pathology.