You don't see the whole world clearly,' Singman says. 'You might think that you have a very wide visual field, but the reality is that your area of clearest vision is actually just a few degrees. That's why we're able to see that candle flame flickering when there's a dark night sky, but not when it's cloudy out. 'The light just doesn't get through,' McCulley explains. 'So depending on the medium that the light is traveling through, those electromagnetic waves will or will not reach your eyes.'Ī similar problem occurs on a foggy day or night. But on Earth's surface, 'you're seeing through the atmosphere, and yellow particular matter in the air is scattering the light,' he says. Theoretically, in a vacuum there's no limit to how far away your eyes could see since light rays can travel an infinite distance, McCulley says. Timothy McCulley, a professor and chair in the department of ophthalmology and visual science with McGovern Medical School at UTHealth Houston. The atmosphere also has a major factor in how well you can distant objects, according to Dr. If the curvature of the Earth didn't exist and instead Earth was a flat surface, we'd have an uninterrupted visual angle from our eyes to the farthest object visible. In addition, the human visual system also transmits and creates visual information that you aren't even necessarily aware of - for example, the amount of ambient light, which controls your natural rhythms of day and night.Īnd our visual acuity extends beyond the horizon even. 'And then your brain takes the images and converts them into something that your conscious mind can appreciate.' 'These are actually different separate channels,' Singman says. Together, those cells work as a team to tell your brain what to visualize, transmitting information about what time of day it is, what's moving and what colors are visible. Some just look at the overall ambient lighting.' 'Some see motion only in one direction, others see motion in another direction. 'Some see colors, some see black and white,' Singman says. Then a layer of tiny nerve cells lining the back portion of the eye known as rods and cones that help send electrical impulses through the optic nerve to your brain, which creates an image or visual perception. When enough light passes through and reaches the retina. Light reflects off objects and passes through the cornea, which bends light rays. Human vision is a complex, intricate process. 'The eye turns light into biometric energy transmitted to the brain,' Singman explains.

Ocean meets sky