Evaluation of Aircrew Low-Intensity Threat Laser Eye Protection

Prototype low-intensity threat laser eye protection (LIT-LEP) spectacles were evaluated for US Coast Guard (USCG) cockpits and night vision goggle compatibility. The impetus for interest in aviation LIT-LEP is driven in part by the fact that easily accessible 0.5-2.0 W high-power laser pointers exceed safety standards for direct on-axis viewing. A repeated-measures experimental design was used to assess LIT-LEP performance relative to a no-LEP control for the following tasks: Near- and far contrast acuity, night vision goggle far-contrast acuity, emissive and non-emissive light source color-vision screening, and USCG multifunctional display color symbol discrimination reaction time and accuracy. Near- and far-contrast acuity results demonstrated good LIT-LEP performance for typical in- and out-of-cockpit lighting conditions. Night vision goggle performance suffered marginally at only one contrast level (85%; 20/30 acuity line). Color vision test results showed good color balance in that S-, M-, and L-cone performance did not demonstrate a clinical diagnostic color defect for emissive or non-emissive light sources when wearing LIT-LEP. Color symbol discrimination reaction-time-task results based on inverse efficiency scores revealed that some non-primary flight display colors exhibited a combination of slower speed and decreased accuracy. The findings will contribute to an acquisition decision as well as guide future LEP designs.

Comparison of visual status of Iranian military and commercial drivers

Background:

There is no legal requirement for Iranian military truck drivers to undergo regular visual checkups as compared to commercial truck drivers.

Objectives:

This study aimed to evaluate the impact of drivers’ visual checkups by comparing the visual function of Iranian military and commercial truck drivers.

Patients and Methods:

In this comparative cross-sectional study, two hundred military and 200 commercial truck drivers were recruited and their Visual Acuity (VA), Visual Field (VF), color vision and Contrast Sensitivity (CS) were assessed and compared using the Snellen chart, confrontation screening method, D15 test and Pelli-Robson letter chart, respectively. A questionnaire regarding driving exposure and history of motor-vehicle crashes (MVCs) was also filled by drivers. Results were analyzed using an independent samples t-test, one-way ANOVA (assessing difference in number of MVCs across different age groups), chi-square test and Pearson correlation at statistical significance level of P < 0.05.

Results:

Mean age was 41.6 ± 9.2 for the military truck drivers and 43.4 ± 10.9 for commercial truck drivers (P > 0.05). No significant difference between military and commercial drivers was found in terms of driving experience, number of MVCs, binocular VA, frequency of color vision defects and CS scores. In contrast, the last ocular examination was significantly earlier in military drivers than commercial drivers (P < 0.001). In addition, 4% of military drivers did not meet the national standards to drive as opposed to 2% of commercial drivers. There was a significant but weak correlation between binocular VA and age (r = 0.175, P < 0.001). However, CS showed a significantly moderate correlation with age (r = -0.488, P < 0.001).

Conclusions:

The absence of legal requirement for regular eye examination in military drivers caused the incompetent drivers to be missed in contrast to commercial drivers. The need for scientific revision of VA standard for Iranian drivers is also discussed. The CS measurement in visual checkups of older drivers deserves to be investigated more thoroughly.

Prevalence of Refractive Errors in Students with and without Color Vision Deficiency

PURPOSE

To evaluate refractive errors in school age children with color vision deficiency (CVD) and those with normal color vision (NCV) in order to make a better understanding of the emmetropization process.

METHODS

A total of 4,400 primary school students aged 7-12 years were screened for color vision using Ishihara pseudoisochromatic color vision plate sets. Of these, 160 (3.6%) students had CVD. A total of 400 age- and sex-matched students with NCV were selected as controls. Refractive status was evaluated using objective cyclorefraction.

RESULTS

The CVD group included 136 male (85%) and 24 female (15%) subjects with mean age of 10.1 ± 1.8 years. The NCV group comprised of 336 male (84%) and 64 female (16%) subjects with mean age of 10.5 ± 1.2 years. The prevalence of myopia (7.7% vs. 13.9%, P < 0.001) and hyperopia (41% vs. 57.4%, P = 0.03) was significantly lower in the CVD group. Furthermore, subjects with CVD subjects demonstrated a lower magnitude of refractive errors as compared to the CVD group (mean refractive error: +0.54 ± 0.19 D versus + 0.74 ± 1.12 D, P < 0.001).

CONCLUSION

Although the lower prevalence of myopia in subjects with CVD group supports the role of longitudinal chromatic aberration in the development of refractive errors; the lower prevalence of hyperopia in this group is an opposing finding. Myopia is a multifactorial disorder and longitudinal chromatic aberration is not the only factor influencing the emmetropization process.

Development of computerized color vision testing as a replacement for Martin Lantern

BACKGROUND

Development and standardization of computerized color vision testing as a replacement for Martin Lantern test. Non-randomized comparative trial.

METHODS

All candidates of SSB, Allahabad, reporting for SMB underwent color vision testing at the eye dept by computerized eye test and currently available tests.

RESULTS

All candidates were subjected to Ishihara chart testing and those found to be CP III were subjected to the confirmatory test on Martin Lantern and the Software. Candidates requiring CP I standards for eligibility were tested on the same on Martin Lantern and on the new software method. On comparison between the Standard Martin Lantern and the Software, the results were consistent and comparable with 82 patients testing CP I on the Martin Lantern and 81 on the software. Of the CP III patients, 253 tested positive on the Standard lantern test as compared to 251 on the software and of the CP IV group, 147 tested positive on the Standard lantern and 149 by the software method.

CONCLUSION

It was found that the software replicated the existing Martin Lantern accurately and consistently. The Martin Lantern Software can be used as a replacement for existing old Lanterns which are not in production since the early 20th century.