Eye structure

What is the Fovea? The fovea or fovea centralis is a small depression at the center of the Visual acuity is the ability to identify the details of objects when you look at them. The fovea contains many cones (the cells that receive visual information). This is why the fovea is responsible for clear vision. 1 Anatomy The central fovea appears as a small flat spot at the retina's center. It's about 1.5 mm in diameter and contains about 199,000 cones/mm squared. 2 A unique feature of this central pit is the displacement of other retinal components to create space for cones. This can be seen through a standard optical coherence tomography (OCT) that indicates foveal thickness. 3 The fovea has no rods. Rods enable scotopic vision or vision at low light levels. They are more abundant in the surrounding retina. Although the fovea is in the retina, it receives its blood supply from the choroid rather than the central retinal artery that supplies the retina. The choroid is a vascular eye layer found between the retina and Functions The fovea enables sharp central vision (foveal vision). This type of vision enables you to perform activities that require visual detail like reading, writing, or driving. To see well, you must focus the image on the fovea centralis. This is the reason why you unconsciously move your head or eyes when reading this sentence — to center the words on the fovea. Fovea Problems & Diseases Left untreated, a variety of eye diseases may impair the fovea, resul...

If the object is far away, the required curvature of lens is less. The ciliary muscles remain relaxed. During this time, the light rays enter parallelly and are converged on the retina. But, when the object is near, the required curvature of lens is more. The ciliary muscles has to push the lens to increase its curvature. During this time, the light rays enter divergently and more focus/bending is needed to form the image on the retina. Hope it helps:) I'm currently learning about the anatomy and fysiology of the eye. What I've learned is that in order for the lens to become more convex, the muscles of the ciliary body tighten (the musculus ciliaris). As a result the ciliary body is moved towards the lens which results in a decreased amount of tension on the suspensory ligaments (zonula ciliaris). The decreased amount of tension results in the relaxation of the lens, so that it becomes more convex. I really hope this is a helpful and that my explanation is correct. English isn't my native language so if there are any mistakes when it comes down to grammar or something similar, I'm very sorry - Our eyes enable us to see all the beautiful things around us. In this video, we're going to see the structure of this eye, the things that make up our eye. When we look at our face, it looks somewhat like this, that's my poor, attempted drawing of face, but if you were to concentrate only on the eye and get rid of all the skin, then you would be left with a ball. And that ball is usu...

Much like a camera lens, the cornea helps to focus light coming into the eye onto the retina. The cornea is also full of nerves that alert us to irritations that could potentially harm our vision and eye health. And the cornea is susceptible to injury. Common injuries of the cornea include "scratches" to its surface known as abrasions. Minor corneal scratches usually heal on their own, but deeper injuries can cause pain and sometimes corneal scarring. Another common ailment of the cornea includes contact lens complications, especially corneal ulceration. An ulcer is a wound on the surface of the cornea caused by bacteria often caused by poor adherence to strict contact lens hygiene; Sometimes, a virus can cause corneal ulcerations like the herpetic virus (the one that causes cold sores on the lips) which 90% of humans have in their bodies. The pupil's job is very similar to a camera aperture which allows more light in for more exposure. At night, our pupils dilate to allow more light in to maximize our vision. In humans, the pupil is round. Some animals have vertical slit pupils while some have horizontally oriented pupils. Pupils appear black because the light that enters the eye is mostly absorbed by tissues inside the eye. If the force of the pulling becomes strong enough, the vitreous humor may actually separate from the retina. This is called a posterior vitreous detachment, as it normally occurs at the back (posterior) of the eye. If this happens suddenly and with a ...

Anatomy What parts of your eye make up vision? There are many different parts of your eye and brain that work together to help you see. The main components of your vision include: • Cornea: This is the front layer of your eye. The • Pupil: The pupil is the black dot in the center of your eye that acts as a gateway for light. It expands in dim light and shrinks in bright light. It’s controlled by the iris. • Iris: This part is typically referred to as your • Lens: The lens is behind the iris and pupil. It works with your cornea to focus the light that enters your eye, much like a camera. The lens brings the image in front of you into a sharp focus, which allows you to see the details clearly. • Retina: Located at the back of the eye, the retina is a layer of tissue that transforms the light coming into your eye into electrical signals. These signals are sent to the brain where they are recognized as images. • Optic nerve: This part of your vision works as the connecting element between the retina and the brain. Your • Tears: Though they are most commonly thought of in relation to crying, tears are meant to keep your eyes wet and help you focus clearly. They also help protect your eyes from irritation and infection. Conditions and Disorders What conditions could affect my vision? There are many different conditions that can affect your vision. These conditions often interfere with the ability of light to pass from the eye to the brain. Healthcare providers can often prevent ...

There are two types of eye muscles: extrinsic muscles that control eye movement and position, and intrinsic muscles that control near focusing and how much light enters the eye. Extrinsic eye muscles (also called extraocular muscles) are attached to the outside of the eyeball and enable the eyes to move in all directions of sight. There are six extraocular eye muscles and one muscle that controls movement in the upper eyelid. Though the extraocular muscles are found within the The main function of the extraocular eye muscles is to control eye movement and eye alignment. They are different from the intrinsic eye muscles, which enable the eye to focus on near objects and control how much light enters the eye. Extraocular eye muscles and their functions Among the extraocular muscles, there are four straight (rectus) muscles and two oblique muscles that work together to move the eye from side to side, up and down, and control its rotation. Additionally, a muscle called the levator palpebrae superioris (LPS) raises the upper eyelid and keeps it in position. All seven of these eye movement muscles are controlled by three cranial nerves: the oculomotor nerve, trochlear nerve and abducens nerve. Recti muscles The eye has four recti muscles, all of which attach to the front half of the eye (anterior to the equator of the eye). These muscles are: • Superior rectus muscle • Medial rectus muscle • Lateral rectus muscle • Inferior rectus muscle Each of the eye’s recti muscles originate...