Ophthalmology (Eye Diseases)
Hospital and Clinic
A Look Inside Your Eyes
Your eyes are the window to the world. View a slide show of the different parts of your eye and how it works.
Your eyes are responsible for providing you with vision, perhaps the most important of the senses. However, the eye is a delicate and complicated structure that needs protection. The ugly truth is that eye injuries can happen at any time and place. Find eye health information on our blog or choose a topic below.
A look inside your eyes
Your eyes are your windows to the world — but they need to be shielded from the elements to keep you seeing clearly.
Upper and lower eyelids protect the front of your eyeballs by blocking foreign objects and bright light. Your eyelids also involuntarily open and close (blink) every few seconds when you're awake.
One of the muscles involved in blinking is called the orbicularis oculi. During each blink, fluid produced by tear (lacrimal) glands passes over the protective dome of clear tissue at the front of your eyes (cornea) and lubricates the surface of the eyes.
Tear drainage pathway
Fluid drains out of the eye through the lacrimal ducts. This process helps keep your eyes moist and washes away germs, dust and stray eyelashes.
The front of your eye
The front of your eye has major parts:
- Sclera. This is the white part of your eye. It is a tough outer wall that helps protect the eye's delicate internal structures. A thin transparent tissue, called the conjunctiva, covers the sclera. Some of the blood vessels visible in the white part of your eye are located within the conjunctiva.
- Pupil. This dark spot is an opening at the center of the iris. It regulates the amount of light that enters your eye.
- Iris. This is the colored part of your eye. It contains a ring of muscle fibers that expand or contract the size of your pupil to control the amount of light entering your eye. This muscle also helps the eye's lens focus on the object of interest.
Inside the front of your eye
Behind the scenes, other parts of your eye work to help you see:
- Cornea. This is a protective dome of clear tissue at the front of your eye. It functions as a convex surface that helps focus light rays before they're fine-tuned by the lens.
- Lens. The lens is a clear, elliptical structure that sits behind the iris. The curvature of your lens changes to sharpen your focus.
- Vitreous cavity. The vitreous cavity extends from the back of the lens to the back of your eyeball, helping to maintain its shape. This area is filled with a clear, jellylike substance called the vitreous.
The back of your eye
Structures at the back of your eye:
- Retina. The retina is a thin layer of tissue that lines the back inner wall of your eyeball. It consists of millions of cells that capture the images focused onto them by your cornea and lens. When light hits these cells, electrical impulses are generated and carried to your optic nerve.
- Macula. The macula is a specialized part of the retina located in the center of the back of the eye. This patch of densely packed light-sensitive cells is essential to your central vision and allows you to see fine detail.
- Optic nerve. The optic nerve carries information gathered by your retina to your brain.
How your eyes move
Each eyeball has six muscles attached to the sclera — the white part of your eye. These muscles, five of which are shown above, allow you to move your eye and track an object without turning your head. The eye muscles also allow you to shift your field of gaze left, right, up, down and diagonally. Your brain coordinates these eye movements so that both eyes can move together when tracking an object.
Eating for Eye Health
Most people have heard that carrots are good for their eyes, but do you know that other foods help protect vision and prevent eye disease?
The National Eye Institute and other vision experts note that a healthy diet is an important factor in eye health. Researchers have found that certain nutrients with antioxidant properties are beneficial. These include carotenoid compounds such as beta-carotene, lutein and zeaxanthin, and vitamins C and E. Zinc and omega-3 fatty acids are also important for eye health.
Mayo Clinic eye and nutrition experts have put together the following lists to help you choose foods for better eye health:
- Vegetables: Kale, collard greens, peppers, broccoli, sweet potato, spinach, peas, pumpkin, carrots and Swiss chard
- Fruits: Peaches, blueberries, oranges, tangerines, mango, tomato, apricot, papaya, cantaloupe, honeydew, avocado and grapefruit
- Sources of zinc: King crab, lamb, bulgur, lean beef, fortified breakfast cereals, beans, lean pork, dark meat of poultry, whole-wheat or buckwheat flours, pumpkin seeds
- Omega-3-rich foods: Salmon, herring, tuna, mackerel, rainbow trout, sardines, flaxseed, English walnuts, canola oil, roasted soybeans
In addition, it's important to maintain a healthy weight. Being overweight or obese increases your risk for developing diabetes, high blood pressure and cardiovascular disease. Each of these conditions can damage small delicate vessels found in the eye and potentially lead to vision loss.
The lists above can be a starting point for planning eye-healthy meals. Here's a sample daily menu:
- Breakfast of whole-grain cereal with berries and walnuts
- Lunch salad of spinach, orange and grapefruit segments, pumpkin seeds and a drizzle of canola oil
- Dinner of oven-roasted chicken legs, sweet potatoes and broccoli, with fresh sliced tomatoes and a dessert of peaches
What other combinations can you envision?
Eye Injury: Tips to Protect Vision
Eye injuries can damage vision and even cause blindness, but most can be prevented. Protect your vision with these tips.
While it's true that many eye injuries happen on the job, almost as many happen around the home. All it takes is a flying champagne cork or a shooting rubber band.
Fortunately, most eye injuries are preventable. Take simple steps to reduce the risk of an eye injury and understand when to see a doctor.
What can you do to prevent an eye injury?
Follow these safety tips to prevent eye injuries around the home.
- Wear protective eyewear during risky activities. Wear safety glasses with side shields anytime you might be exposed to flying particles, objects or dust.
- Wear goggles when exposed to chemicals. Take precautions even if you're just a bystander.
- Supervise your child's use of tools. Pencils, scissors, forks and knives can all cause serious eye injury. Keep in mind that common household items — such as paper clips, bungee cords, wire coat hangers, rubber bands and fishhooks — also can be dangerous.
In the yard
- Protect your eyes while doing yardwork. Use protective eyewear every time you operate lawnmowers, lawn trimmers and leaf blowers.
- Keep children away from flying debris. Make sure young children stay out of the yard while a lawnmower is being operated.
- Store hazardous substances out of reach. Keep fertilizers, pesticides and pool chemicals away from children at all times.
Cooking and cleaning
- Use caution with chemicals and cleaners. Carefully read the labels of chemicals and household cleaning supplies, such as bleach, before using them. Don't mix products. Keep all chemicals and sprays out of a child's reach.
- Be careful when cooking or using hot objects. Use grease shields to prevent the splattering of hot grease or oil. Avoid using a curling iron near your eyes.
- Keep sharp kitchen tools and utensils away from small children. Store them in child-proof locations, and avoid setting them down within reach of young children.
On the move
- Eliminate hazards that may cause falls. Secure rugs and railings. If a child or elderly adult lives in your home, use safety gates at the top and bottom of stairs, and consider covering sharp furniture edges and corners with a cushioning material.
- Use car seats. Make sure your child is properly secured in a car seat and that the seat belt or shoulder belt fits tightly. Don't allow a child age 12 or younger to ride in the front seat. Store loose items in your trunk or secure them to the floor of your vehicle.
- Avoid certain children's toys. Don't allow your child to play with non-powder rifles, such as pellet guns or BB guns. Avoid projectile toys, such as darts, bows and arrows, and missile-firing toys.
- Don't allow your children to use laser pointers. Laser pointers, especially those with short wave lengths such as green laser pointers, can permanently damage the retina and cause visual loss with exposures as short as a few seconds. As an adult, be cautious when using laser pointers. Avoid directing the beam toward anyone's eyes.
- Wear protective eyewear during sports. Any sport featuring a ball, puck, stick, bat, racket or flying object, is a potential risk of eye injury. Choose sports protective eyewear labeled as ASTM F803-approved. Eyewear that hasn't been tested for sports use, such as sunglasses, can cause more harm than no eyewear at all.
- Keep small children safe around dogs. When young children are bitten by dogs, eye injuries frequently occur.
- Forgo backyard fireworks. Leave fireworks to trained professionals.
- Use caution when opening a champagne bottle. Don't shake the bottle. Point the bottle at a 45-degree angle away from yourself and any bystanders. Firmly place your palm over the cork while removing the wire hood. Place a towel over the entire top of the bottle, grasp the cork and slowly twist the bottle until the cork is almost out of the neck. To prevent the cork from being discharged like a missile, maintain slight downward pressure on the cork just as it comes out of the bottle.
What are the signs and symptoms of an eye injury?
It's not always easy to identify an eye injury — especially in a child. Seek medical care immediately if you notice any of these signs or symptoms:
- Obvious pain, trouble opening the eye or trouble seeing
- A cut or torn eyelid
- One eye not moving as well as the other eye
- One eye sticking out farther or seeming more prominent than the other
- An unusual pupil size or shape
- Blood in the white part of the eye
- An object on the eye or under the eyelid that can't easily be removed
What can you do if an eye injury occurs?
When an eye injury occurs, seek medical help from an ophthalmologist or another doctor as soon as possible — even if the injury seems minor. Delaying care could lead to permanent vision loss or blindness. In addition, take simple steps to prevent further damage. For example:
- Don't touch, rub or apply pressure to the eye
- Don't try to remove an object that appears stuck on the surface of the eye or an object that appears to have penetrated the eye
- Don't apply ointment or medication to the eye
- Flush out any chemicals the eye has been exposed to with plenty of clean water
- Gently place a shield or gauze patch over the eye until you can get medical attention
An accident can happen in the blink of an eye. Being prepared — both through prevention and quick action in case of an emergency — can help keep you and your loved ones seeing clearly.