According to The Merck Manual Home Health Handbook, light travels through the sclera, cornea, pupil and lens before stopping at the retina, respectively. Once at the retina, the information from the light is converted to electrical impulses for the brain to interpret.Continue Reading
The Merck Manual Home Health Handbook describes the sclera as the eye's tough, outer covering. It is transparent, allowing light to pass through. Next, light passes through the cornea. The cornea roughly focuses light towards the pupil. The pupil is a dark circle in the center of the eyeball. It is surrounded by the iris, which constricts and expands to change the size of the pupil. Acting similarly to a camera's aperture, it regulates the amount of light that enters the eye's interior.
After entering the pupil, that light passes through the lens. The lens is responsible for fine focusing light. It does this by slightly altering its shape to bend light rays at the correct angles. The light then lands on the retina, which is a surface at the back of the eye that is covered in photoreceptors. Photoreceptors sense different types and wavelengths of light that are converted into electrical signals. The optic nerve delivers these signals to the brain where they are decoded into images, notes The Merck Manual Home Health Handbook.Learn more about Vision
Double vision in a single eye can be caused by cornea problems, lens problems and eye muscle problems, according to WebMD. Additionally, this problem may also occur when the brain fails to combine images from the eye due to damage of the nerves.Full Answer >
Astigmatism is a condition that causes blurred vision when the lens or cornea of an eye has an irregular surface contour, according to Mayo Clinic. Rather than having a consistently smooth curvature, an astigmatic lens or cornea has abnormal curves and flattened areas, changing how the eye processes light.Full Answer >
During cataract surgery, a small incision is cut on the side of the cornea, and a device that emits ultrasound vibrations is inserted into the eye to break the cloudy lens known as the cataract, which is ultimately removed. A clear lens is then inserted to replace the cloudy lens.Full Answer >
Cataracts are removed after the eye surgeon makes an incision in the patient's cornea and then carefully removes the clouded lens. Before surgery, topical medications are used to dilate the pupil and numb the eye. The patient may also be sedated.Full Answer >