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.Know More
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
An image is formed in the human eye when light passes through the pupil, is refracted by the lens and is absorbed by pigment cells in the retina, altering the pigments and triggering neurons to fire. The particular arrangement of the stimulated cells is interpreted by the brain into a separate image for each eye. The two eyes look at images from slightly different angles, allowing the perception of depth.Full Answer >
A macular hole is a small break that occurs in the center of the eye's retina. The macula is a light-sensitive part of the retina that provides the sharp central vision that aids in seeing fine detail, reading and driving.Full Answer >
Retinal separation, or detachment, occurs when part of the interior lining at the back of the eye, known as the retina, breaks away from the underlying tissue, Medical News Today states. Depending on the type of detachment, fluid from the vitreous layer of the eye may collect behind the retina.Full Answer >
The difference between wet and dry age-related macular degeneration is that the wet form involves the growth of new blood vessels under the retina of the eye, while the dry form involves the breakdown of cells in the macula. Vision loss is typically more serious with wet macular degeneration.Full Answer >