Structures and functions of human eye
Movement of the eyeball
Eye diseases and disorders
Examination of eyes
Management of eye disorders or diseases
Natural or home remedies for eye problems
Eye is the organ of vision and a paired organ situated in bony orbit of the head. Lacrimal bone and the maxilla are the parts of bony cavity in which eyeballs are situated. Structurally, an eye is composed of various parts, which receives light stimulus in the form of electrical signal and delivers this stimulus to the brain for various activities.
Usually, the eye is composed of the transparent media and the wall.
The transparent media of eye –
- Conjunctiva – It covers the sclera and lines the eyelids. It produces mucus and tears, and lubricates the eye. It also prevents the invasion of microbes or germs into the eye.
- Cornea – It is a visible clear bulge located at the front of the eye. The cornea has five layers viz. corneal epithelium, Bowman’s layer, corneal stroma, Descement’s membrane and corneal endothelium. The function of cornea is image-forming process by refracting the light entering into the eye through the pupil and on to the lens.
- Lens – Lens are in the form of fibers with live cells. There are no blood vessels or nerves in lens, and the nutrients are obtained from aqueous humor through diffusion.
- Aqueous Humor – It is a jelly-like substance situated in the front chamber of the eye. It provides nutrients to cornea and lens, and maintains intraocular pressure i.e. approximately 25 mmHg.
- Vitreous Humor – It is gelatinous with loose connective tissue. It contains water, collagen and hyaluronic acid. It maintains the pressure and prevents retinal detachment. It supports the lens and retina.
The wall of the eye –
- Retina – It is the inner layer of the eye. It may be described as the screen. The ray of light passes through the transparent media of the eye and finally reaches the retina. It contains photosensitive elements that convert the light into nerve impulse along the optic nerve onto the brain. Hence, retina plays a major role in functioning of eye. The photosensitive elements of retina are rods (utilized at night – sensitive to black and white) and cones (utilized during daytime – sensitive to colors).
- Uveal tract – This structure is composed of three parts viz. choroid (pigmented and highly vascular), ciliary body (produced aqueous and vitreous humor) and iris (vascular and colored). The function of uveal tract is to increase sensitiveness to poor light and provides nutrition to eye.
- Sclera – It is a tough white sheath occupying the outer side of the eyeball. Ciliary nerves are connected to sclera with small capillaries for blood supply.
Pupil – The pupil is an important part of an eye. It is situated in the center of the eye, which is generally dark and circular. It is regulated by the light reflex, which is also called as pupillary reflex.
Iris – The iris is the colored part of the eye and the function of the iris is to adjust the pupil size and to modulate the amount of light administered into the eye.
Optic nerve – The optic nerve is an important nerve as the main nerve supply to the eye is through this nerve. It progresses from the back portion of the eyeball into the skull through the optic commissure (optic chiasma) to each side of the brain. There are one million fibers channeling information from rods and cones of the retina and transmits visual information to the brain. The optic nerve is considered as the second (II) cranial nerve.
One can move their eyeball due to proper functioning of six extra-ocular muscles. The contraction and relaxation of theses muscles helps in easy movement of the eyeball.
- Superior rectus muscle
- Inferior rectus muscle
- Lateral rectus muscle
- Medial rectus muscle
- Superior oblique muscle
- Inferior oblique muscle
These are the main six extra-ocular muscles that help in coordination of movement in both the eyes. There is one more muscle called as Levator palpebrae superiosis, which retracts and elevates the eyelids.
One may experience eye problems due to underlying medical condition or primary affection of eyes. Different eye conditions indicate different signs and symptoms.
- Cataract – Cataract is characterized by clouding of internal lens of the eye that causes blurry or foggy vision. Cataract surgery is a commonly used to treat cataract.
- Conjunctivitis – It is the inflammation or infection of the conjunctiva, which covers the front part of the eye. In inflammatory conditions, it is termed as “pinkeye”. The infection is caused due to allergies, viruses, or bacterial microbes. One may experience redness in eyes with watering and swelling of eyes.
- Blepharitis – It is the inflammatory condition of eyelids. Gritty sensation and itching are the common symptoms of blepharitis.
- Keratitis – It is characterized by inflammation of cornea that causes itching and swelling of the cornea. Typically, the germs or the microbes enter into cornea through trauma or corneal abrasion. Corneal abrasion is a scratch in the front part of the eye. The common symptoms are pain, gritty sensation and light sensitivity.
- Glaucoma – It is caused due to increased intraocular pressure inside the eye causing progressive loss of vision. Usually, there are two types of glaucoma, closed-angle glaucoma and open-angle glaucoma. This condition goes undetected for many years. Both conventional and laser surgeries are useful in treating glaucoma.
- Diabetic retinopathy – Diabetic retinopathy is one of the commonest eye disorders seen in diabetic subjects. Uncontrolled diabetes or high levels of blood sugar damages the blood vessels in the eye. Damaged blood vessels can lead to permanent loss of vision.
- Dry eye – Dry eye is a result of underlying medical conditions such as scleroderma, lupus, vitamin deficiencies and Sjogren’s syndrome. In this condition, eyes fail to produce enough tears or produces poor quality tears. Treating the underlying medical condition and vitamin deficiencies may suffice the problem of dry eye.
- Black eye – It is the condition of eye characterized by swelling and discoloration of the eye due to trauma to the face or eye, causing bruise after contusion or a blow.
- Chalazion and stye – A chalazion is a small bump-like swelling that occurs on the eyelid due to blockage of oil gland, and often disappears in a month without treatment. However, one should see a doctor if a swelling is large and painful. On the other hand, stye is an inflammation of oil producing gland on the eyelid, which is small and less painful.
- Hyphema – Usually, hyphema is caused due to trauma or injury leading to bleeding in front of the eye between the pupil and the cornea.
- Optic neuritis – The optic nerve becomes inflamed due to overactive immune system. It is characterized by painful vision loss, affecting a single eye or both the eyes.
- Pterygium – A vision problem caused due to thickened conjunctival mass on the inner side of the eyeball.
- Strabismus – It is a structural deformity, wherein the eyes do not point in the same direction. In this condition, there can be amblyopia (lazy eye or weak eye) with other eye functioning normally.
- Uveitis or Iritis – Uveitis is the inflammation of colored part of the eye due to bacteria, viruses or overactive immune system.
- Diplopia – This condition is characterized by double vision i.e. simultaneous perception of two images of a single object.
- Night blindness – Night blindness is also known as Nyctalopia. It is caused due to congenital eye problems and Vitamin A deficiency. In this condition, a person is unable to see in dim light or there is an insufficient adaptation to dim light or darkness.
- Color blindness – It is the inability to see color or perceive color differences, in normal lighting conditions. It is caused due to mechanical or chemical trauma to eyeball and optic nerve.
- Refractive errors – Following are the refractive errors, which may require optometrist or medical attention:
- Hyperopia – It is also known as farsightedness i.e. inability to see near objects with clear vision in the distance.
- Myopia – It is also known as nearsightedness i.e. inability to see far objects with clear vision close up.
- Presbyopia – It is an age-related disorder characterized by the inability to focus on the near objects.
- Astigmatism – It is an optical defect with blurry vision caused by the cornea.
These are the common eye conditions caused due to various factors, which need medical attention to avoid further damage to the eye. Chronic conditions of eye can lead to temporary or permanent loss of vision. Therefore, one should immediately get their eyes scrutinized by an eye specialist regularly, especially people suffering from diabetes and high blood pressure.
Regular check up of your eyes plays an important role in proper functioning of eyes. It helps in diagnosing or detecting eye condition at earliest, followed by appropriate treatment or management to avoid unwanted complications of eyes, which may include permanent vision loss.
An ophthalmologist (eye specialist) or optometrist performs an eye examination. Health-care practitioners often suggest that every individual should undergo regular and thorough examination of eyes as a part of routine health care, because many eye conditions are asymptomatic.
Few basic examinations of eyes are as follows:
- External examination – Direct inspection of eyes and eyelids can be done for various inflammatory conditions of eye. The conjunctiva and sclera can be inspected through direct light by retracting upper and lower eyelid.
- Refraction – Measuring your refractive error is crucial to detect refractive errors of eyes such as hyperopia, myopia and astigmatism. A corrective lens is required for proper focusing and detection of refractive error. There are two types of refraction tests viz. objective refraction and subjective refraction. In objective refraction, a retinoscopy or an auto-refractor is used to detect eye problems, whereas in subjective refraction, your eye specialist may use phoropter or trial frame to detect refractive error.
- Visual acuity – It helps in detecting fine details and measurement of eye’s ability to focus on things from a certain distance. The standard definition for normal visual acuity is 20/20 or 6/6 vision.
- Pupil function – Your ophthalmologist may check your pupil function by using swinging-flashlight test, which is also used to detect neurological damage.
- Visual field testing – In this test, each eye is tested separately to assess the peripheral field extent by confrontation field-testing.
- Ocular motility – In case of diplopia or neurologic disorder, your physician performs ocular motility.
- Slit lamp – Slit lamp examination is done by your ophthalmologist in an ophthalmology clinic. The anterior eye structures and ocular adnexa are inspected with a slit lamp, which is mounted with a microscope with an adjustable illumination source. Other examination tools such as binocular slit-lamp, ophthalmoscope and gonioscope are also used.
- Intraocular pressure (IOP) – IOP is measured by using Tonometry devices. The normal range of IOP should be 10-21 mmHg.
- Retinal examination – A direct ophthalmoscope is used in examination of retina. A special eye drop is instilled before the examination with ophthalmoscope.
Ophthalmologists may advise few specialized eye examination, which are as follows:
- Color vision
- Vergence system
- Accommodative system
- Optokinetic system
- Corneal pachymetry and corneal topography
- Laser polarimetry
- Retinal tomography
- Amsler grid
- Ultrasound biomicroscopy
Eye examination in children is of utmost importance, as early detection of any eye condition can be corrected by therapeutic measures.
Children need few basic visual skills for learning, which are as follows:
- Near vision and distance vision (Landolt C chart, tumbling E chart)
- Eye movement
- Eye teaming
- Peripheral vision
- Hand-eye coordination
- Focusing skills (accommodation)
These examinations play an important role in eye care. Hence, all these examinations or tests are useful in detecting eye problems for early diagnosis and timely treatment. One can avoid eye complications such as temporary or permanent vision loss, by early detection of eye ailments, especially those conditions of eyes that are asymptomatic.
You should consult your eye-care physician, if you experience any kind of sensation in your eyes or you detect any deformity or vision problem. Any signs and symptoms of eye for longer period can lead to severe ophthalmic conditions. Therefore, to avoid complications of eye(s), you should immediately get your treatment done by your consulting physician or ophthalmologist.
In case of bacterial or viral infections such as conjunctivitis, blepharitis, stye, retinitis, etc. oral medication, eye drops, or eye ointments are used to subside the infection. Antibiotic eye drops are used to treat infectious or inflammatory conditions of eye(s).
In case of severe eye disorders such as glaucoma, diabetic complications, corneal problems (keratoconus), cataracts, etc. conventional or laser surgeries are preferred. Refractive errors are also managed by laser treatment with desired results.
Commonly used eye drops for different conditions of eye(s) –
- Antibiotic drops –
Few antibiotic drops or ointments such as ofloxacin, gatifloxacin, moxifloxacin, erythromycin ointment, bacitracin ointment, etc are used in bacterial infections of eye(s).
- Glaucoma drops and medication –
There are few ingredients used in treating glaucoma, such as brimonidine, bimatoprost, timolol, dorzolamide, travoprost, latanoprost, acetazolamide and methazolamide.
- Steroid drops –
Your physician may prescribe you few steroid drops such as prednisolone acetate or fluorometholone, in case of severe eye conditions.
- Dilation drops –
Few drugs such as phenylephrine, tropicamide, cyclopentolate and atropine are used as dilation drops.
- Anesthetic drops –
Physicians use anesthetic drops such as proparicaine, tetracaine, etc. depending on the eye condition.
Laser eye surgery –
Laser eye surgery is a type of vision repair surgery used in managing refractive errors of eye(s) and other eye conditions. It is a surgical procedure used to correct vision problems with desired results and effectiveness.
There are different types of laser eye surgery, which are useful in reshaping the cornea, as follow:
- LASIK – Laser in-situ keratomileusis, used in refractive errors such as hyperopia, myopia and astigmatism.
- LASEK – Laser epithelial keratomileusis, used in refractive errors and reshaping the cornea.
- PRK – Photorefractive keratectomy, used in reshaping the cornea and refractive errors.
- LTK – Laser thermokeratoplasty, used to correct hyperopia and astigmatism, without any cut or removal of tissue.
- ALK – Automated lamellar keratoplasty, used in hyperopia, myopia and reshaping of cornea.
- RK – Radial keratotomy, most frequently used procedure in correcting shortsightedness. However, due to advancement in laser techniques such as LASIK and PRK, radial keratotomy is rarely used.
- AK – Astigmatic keratotomy, this is not an actual laser eye surgery, but a proper surgical procedure used to correct astigmatism. AK can be used alone, or in combination with LASIK, PRK or RK.
In case of eye conditions or complications caused due to underlying medical conditions such as uncontrolled diabetes (diabetic retinopathy) and high blood pressure (hypertensive retinopathy), you should consult your physician for corrective measures of theses complications, as early as possible. These complications may lead to permanent loss of vision. One should undergo periodic and thorough examination of eyes in case of diabetes and hypertension with proper and regular medications for underlying diseases.
One should not take their eye(s) health for granted, as they are crucial in performing innumerable activities. Any disturbance in eye(s) leads to mental irritation. You should protect your eyesight in order to perform daily activities with great ease and comfort.
Following are few tips for good vision –
- Healthy eating habits for good vision –
You should adopt healthy eating habits for proper vision. Reports suggest that, regular consuming of nutrients such as vitamins C and E, omega-3 fatty acids, zinc and lutein helps in correcting the age-related eye problems such as cataracts and macular degeneration.
One should consume following foodstuff for healthy eyes:
- Eggs, beans, nuts and non-meat protein foods
- Green, leafy vegetables such as collards, kale and spinach
- Tuna, salmon and other oily fish
- Citrus fruits or juices
- Carrot (Vitamin A) useful in night blindness
A well-balanced diet helps you in maintaining normal body mass index (BMI), which helps in prevention of obesity-related diabetes. Diabetes is the main cause for permanent blindness in many adults.
- Use sunglasses for safe vision –
Sunrays emit dangerous ultraviolent (UV) rays. Excessive exposure of UV rays can lead to eye disorders such as macular degeneration and cataracts. To avoid these eye conditions one should use the proper sunglasses, which will protect your eyes from dangerous UV rays. You should choose sunglasses that blocks 99% to 100% UV rays. You can use contact lenses that offer UV protection. In addition to UV protected contact lenses, you can use sunglasses for more protection.
- Quit smoking for good eyesight –
Eye condition such as macular degeneration, cataracts and optic nerve damage are caused due to smoking. One should quit smoking to avoid eye diseases caused due to smoking.
- Use safety eyewear –
You should use safety eyewear regularly while handling airborne or hazardous materials at your home, at workplace, or while playing sports. While playing or riding one should wear helmets, protective facemasks, sports goggles, etc. You should protect your eyes to avoid entrance of foreign substances, which further helps in preventing infections.
- Avoid constant using of Computer –
Excessive staring at computer screen can lead to eyestrain, difficulty in focusing, dry eyes, blurry or foggy vision, headaches, etc. One can protect their eyes by following few steps, such as –
- Use glasses or contact lenses prescribed by your eye-specialist or optometrist while using computer
- Adjust your computer in such a way that your eyes are positioned properly with the top of the monitor.
- You can use anti-glare screen while using computer
- If you feel dryness of eyes, try to blink more.
- Rest your eyes every 20 minutes by looking 20 feet away for at least 20 seconds.
- Use a comfortable, supportive chair to position yourself in a proper manner (feet should be flat on the floor).
Our eyes are used frequently in day-to-day activities. They are constantly exposed to computer monitor, smartphone, television and environmental pollution. These factors of constant straining of eyes lead to ophthalmic problems. Therefore, to maintain healthy eyes, one can follow few simple and easy exercises, mentioned below –
- Rub your palms together until you feel warm. Close your eyes, place your warm palms over your eyelids, and allow them to relax. You should not let light into your eyes. Do this procedure whenever you get free time.
- Tightly close your eyes for 4-5 seconds and then open them for 4-5 seconds, repeat this procedure 7 to 8 times.
- Eyelid massage – After closing your eyes, gently massage your eyelids with washed hands using your fingers in circular movements for 1 to 2 minutes.
- Hot or cold compress – Soak a towel in hot or cold water and gently place it on your closed eyelids and on your eyebrows for few seconds.
- Gently press three fingers against your closed upper eyelids, hold them for 2-3 seconds then release. Repeat this exercise five times.
- Sit and relax for few minutes. Then roll your eyeballs clockwise, then counter-clockwise, repeat this five times and blink in between the procedure. After finishing this exercise, start with up and down eye movements for 8-10 times, then side-to-side eye movements for 8-10 times.
- Focusing on object – One should focus on a distant object i.e. 50 m away, for 10-15 seconds. Then, slowly refocus on a nearby object i.e. 10 m away, without displacing your head. Repeat this exercise five times.
- You should frequently blink your eyes to keep your eyes fresh. This is a simple exercise for computer users, which helps in avoiding eyestrain.
Advantages of eye exercises –
- Reduces the risk of developing diseases or disorders of eye(s)
- Improves the quality of vision
- Prevents dryness of eye(s)
- Improves concentration level
- Reduces eyestrain problems
- Enhances peripheral vision
There are few common eye problems that you can manage safely at home using natural or home remedies. However, in severe eye conditions or eye disorders caused due to underlying medical conditions, you should consult your ophthalmologist (eye-specialist) for proper medical evaluation and treatment.
Few common home remedies for common eye problems –
- Eye allergies –
If you are suffering from eye allergies, prevent yourself from dust, pets, mold or pollen, to relieve your symptoms of red eye, itching and watering. Wear sunglasses when you go out, to avoid dust particles entering into your eyes.
- Conjunctivitis – Many cases of conjunctivitis do not respond to antibiotic eye drops. Apply cool compresses to your eye. This infection is highly contagious, so one should not share towels, handkerchiefs, pillowcases, or cosmetics. You should wash your hands often.
- Black eye – You should apply an ice pack to the affected eye for 15 to 20 minutes once in every hour to reduce the swelling and pain.
- Stye – Usually, stye is harmless and a self-limiting problem, it goes away within a week. Soak a washcloth in warm water, twist or squeeze it and then place it over the closed eye for few minutes. Once the warm washcloth becomes cool, repeat the procedure again for at least 3 to 4 times a day. Do not squeeze the stye as it can spread the infection throughout your eye.
If you suffer from blurriness, severe pain in eyes, serious injuries, or double vision (diplopia), you should not try treating these eye problems on your own. You should immediately consult your physician for better medical assistance, to avoid further damage of eye(s).
Few herbal remedies for eye care –
- Eyebright – Eyebright eye drops are used in treating conjunctivitis.
- Coleus – Coleus (forskolin) eye drops reduced the intraocular pressure, thereby helpful in treatment of glaucoma.
- Ginkgo – It improves blood supply to the retina. It is an anti-oxidant and protects neurons (nerve cells). It is also used in glaucoma, and improves vision.
- Green tea – It is an anti-oxidant and helps in chronic conditions or eye such as cataracts, glaucoma and macular degeneration.
- Cannabis – It reduces intraocular pressure within the eye(s) in people suffering from glaucoma. However, one should consider the side effects and legality of cannabis.
- Bilberry – It improves night vision and reduces eye fatigue.
Few researchers are studying the effect of garlic and turmeric in case of cataracts due to their anti-oxidant powers. One should consult their physician before implementing any herbal or home remedies to treat eye conditions.
It is always safe to consult your ophthalmologist or physician, if you suffer from any eye condition. Your doctor will examine you properly with required instruments to detect the root cause of the eye disease. Accordingly, you doctor will plan a suitable and best possible treatment to cure your eye problems. Self-treatment of any eye condition is not advisable, as your eyes are crucial for innumerable activities. You should take utmost care of your eyes by periodic and thorough examination under your eye specialist, to avoid eye complications, which goes undetected on many occasions.