Vision standards for driving in Trinidad and Tobago

Objective: To research the licensing system with respect to vision standards, and the process of assessing vision at licensing offices. We identified areas where there may be problems, which can hinder the safety of drivers and other citizens and proposed solutions for these issues. Design and Methodology: Methods of information gathering includedconducting interviews with the head licensing officer at each licensing office branch. Data such as the types of chart, distance from the chart and room lighting were also measured and recorded at each office. Information about the vision screening process was gathered through the interviews. Results: It was found that there were no set standards in Trinidad and Tobago for assessing the vision of individuals wanting to obtain a driver's license. Individuals performing the vision assessment at the offices were not trained to do so and did not perform it on everyone. There were variations in the types of chart used, the chart distance used for testing, and room lighting, which can significantly affect the results. Conclusions: There is room for improvement in the system and methods of vision screening in Trinidad and Tobago. Other features of vision testing including peripheral vision and contrast sensitivity should be taken into consideration for a proper assessment of vision to be done. There is also a need for more extensive research to be done to aid policymakers in making sound decisions.

Comparing the peek retina to fundus camera, direct ophthalmoscope and Volk lens for the viewing of the optic disc

Objective: To compare the Peek Retina device with a fundus camera, direct ophthalmoscope and Volk lens. Design and Methodology: The comfort for the patient, efficiency when using the equipment, image quality, time taken, and usability of the equipment were analysed for the four different equipment when the optic disc was viewed. The direct ophthalmoscope, Volk lens and the slit lamp, and a fundus camera were used to view the optic disc in 50 patients at the UWI Optometry Clinic. This four equipment comparison study was done using questionnaires for both the patient and examiner. Results: It was found that peek retina was more comfortable than direct ophthalmoscope and the Volk lens, and it was similar to the fundus camera. Likert scale values showed that the fundus camera was the most efficient and the peek retina the least. The time frame using the fundus camera was the least which was 2.94 minutes compared with using the Volk lens which took the most time of 3.98 minutes. The usability values showed that it was easier to use the fundus camera 1.58 compared to peek retina 2.68, possibly because of the lack of experience with this new device. Conclusion: There was a significant difference among the different devices for the variables examined. The fundus camera was the best at most of the variables and the Peek Retina was the least, while the Volk lens was the most chosen to view the optic disc again due to the clear, stereoscopic and wide view of the back of the eye.

Microvascular endothelial function and regional differences in vasodilation in the human cutaneous microcirculation in primary open angle glaucoma

Objective:Blood flow in the optic nerve head and finger skin are related in subjects with a primary vascular dysregulation (PVD). Since PVD may also occur in glaucoma, the aim of this study was to investigate the responses of the microcirculatory blood flow at the finger and forearm skin to iontophoresis of endothelial-dependent (acetylcholine - ACh) and endothelial-independent (sodium nitroprusside - SNP) vasodilators in primary open angle glaucoma (POAG). Design and Methodology: We studied 22 patients with POAG and 27 control subjects. The vasodilator responses to iontophoresis of ACh and SNP performed at the finger and forearm skin were determined, with skin microcirculatory blood flow being expressed as cutaneous red cell flux (RCF) as measured by Laser Doppler Flowmetry. Results: ACh and SNP induced significant increases in RCF from baseline (p<0.001) at both the finger and forearm skin sites in POAG patients and controls, but there was no difference in vasodilation between the subject groups. Within controls and POAG patients, for both ACh and SNP, the baseline RCF was higher in the finger than in the forearm skin (p<0.05). The vasodilatory response to ACh in the finger was also higher than in the forearm skin (p<0.05) i controls and POAG. The mean vasodilatory response to SNP in the finger was higher than in forearm skin (p<0.05) in controls and POAG. Conclusions: The vasodilatory responses to acetylcholine in POAG suggest normal microvascular endothelial function. The higher baseline RCF and vasodilatory responses in the finger than in forearm skin sites may reflect the difference in vascularity between these sites.