They once were blind but now they see. Which begs the question — what exactly do people see when they gain sight for the first time? Often, it’s terrifying.

What happens when people first really look at the world? Generally, we don’t know. They’re far too young to tell us what’s going on in their mind. By the time children are old enough to articulate what they see, they don’t remember what the world looked like in their first few weeks of life. There are special occasions, though, when full-grown adults can see for the first time. For the most part, they see a complete confusion. Often, that does a lot of emotional damage.

One of the earliest-known cases of regained sight is Virgil, the Roman poet. At age fifty, he had cataract surgery and regained his sight. Soon after, he wished he hadn’t. This is common to many blind people who regain their sight. Unlike infants, who are catered to, whose brains are primed for learning, and who have no option but to learn, blind people are asked to replace a familiar sensory system that reliably guides them through the world with an unfamiliar one that does nothing but confuse them. Sometimes the strain of assimilation is too much. Like many other patients, Virgil would shut his eyes and pretend he was still blind when the situation became overwhelming. He became depressed and died of pneumonia soon after his surgery. Although he had seen the world with his eyes, he retained his “mental blindness,” or what experts call “visual agnosia.”

For someone to see an object, the eye needs to pick it up, but the brain also needs to recognize it. This process takes both practice and a certain physical ability in the brain. Agnosia patients have generally suffered brain injuries and lost the ability to understand what they see – they see a rectangular object with a brown circle on top and a loop on one side, but don’t understand that they’re looking at a cup of coffee. There are only shapes. Those who have been blind most of their lives “wake up” with a certain amount of visual agnosia.

Spatial distance is often the primary problem they run into. One man saw people walking away from him as inexplicably shrinking. Another would practice spatial recognition by going out in a field and throwing his boot as far as he could. He’d hold out his hand to grab it, and if it wasn’t in reach, step forward before trying again.

Another area that many newly-sighted people find inexplicable is paintings and other visual representations. They can comprehend real objects, but not painted ones. When they do understand what the paintings are meant to represent, the shadows that are meant to define space and give shape just look like dark marks on the painting. Which, technically they are. It’s only a willful visual laziness on the part of the sighted that lets us see these paint blotches as shadows rather than shapes and colors.

Because we develop familiarity with faces and facial expressions at specific times in our lives – those who are deprived of human contact or changing facial expressions at that age often have trouble reading expressions for their entire lives – formerly blind people are often face-blind, or unable to decipher emotion from facial expression. Some have trouble differentiating between male and female faces.

Which isn’t to say that these people always have a completely blank slate, visually-speaking. It’s been shown that when blind people read Braille the visual cortex activates. They “see” with their brains, just not with their eyes. Surgeries on children are particularly successful. One doctor was surprised to find that a ten year old was coordinated enough to catch paper balls thrown at him only a few weeks after surgery, and knew the medical staff by sight. Young people assimilate the world very quickly.

In one famous case, a man regained his sight after being functionally blind since the age of ten months. (He was able to point at bright objects, but nothing more.) He had worked with machines and mechanics, and was able to read the clock in his hospital room shortly after recovering from surgery. The shapes, however unfamiliar to his eyes, made sense to his brain. He was also able to find his way around the room, coordinating what he saw with distances that he had walked before surgery.

When psychologists asked him to draw what he saw, starting with people, his house, and a bus,his drawings were quite extraordinary. They began as simple shapes. Houses were perfect squares with square windows and a rectangular door - the way a small child would draw a house. His buses were similar, squares and circles. As he developed, he added more detail to the design of the bus, including the text on its signs, but forgot to add parts of the outline of the bus, so that windows and wheels appear to be floating. He can draw people, in a symbolic way - two arms, two legs, and a head with all the features. When asked to draw an elephant he drew a smeared gray shape with four legs and tubes for both head and tail. Once he couldn’t represent the object with shapes or features that he knew had to be there, he couldn’t recreate it.

Learning to see is, in many ways, like learning to read. It’s a complex process involving time, practice, and mental ability, but it’s a process that only works one way. At some point we lose the ability to look at a “stop” sign and not automatically read the word “stop” – but at least not understanding the written word is imaginable. The idea of not understanding that a stop sign is a sign, or that it is a solid object placed in front of one thing and behind another, reaches too far back into our history. We have to look at others to understand what the world looks like before we connect “looks” to the world.