History of optometry
Optometry can be traced back to the first studies on optics imaging of the eye. The history of optometry is linked to the work of opticians because the correction of refractive errors depended on experiments with lenses. The first known lens is a plano-convex piece of polished rock crystal. The lens was 3.8 cm in diameter with a focal length of 11.5 cm. It was found in the ruins of Nineveh. It seems to have been created around 750-710 BC. Historians are still unsure if old lenses of this kind were used to correct vision. They believe the lenses were more likely used as burning glasses.
While the Greeks were working on laws of reflection in mirrors, they did not fully understand the concept of refraction. They had knowledge about the crystalline lens in the eye but did not know about the retina. They thought that rays of light came from the eyes. This myth existed until Leonardo Da Vinci established the role of the retina with his studies on light rays. This was a big discovery in the optic field.
Another major step forward was from an English monk named Roger Bacon. In 1268, he demonstrated that “by placing a sphere on a book with its plane side down, the letters appear large”. This was the really first time someone suggested that plano-convex lenses could improve vision. While this discovery was important, he did not pursue his theory.
To this day, historians do not know the name of the inventor of the first spectacle. However, Fra Giordano Di Rivalto confirms that spectacles were created at the end of the 13th century as he wrote in 1305 “It is not yet twenty years since the art of making spectacles, one of the most useful arts on earth, was discovered”. Around this time Italian lawmakers started controlling the quality of the lenses. From the 14th century up to the 16th century, spectacles were primitive and the problem was to find out how to keep them on the nose. It was in the early 18th that spectacles with sides appeared. At the end of the 18th century what would be later known as bifocals were created, and at the beginning of the 19th century, astigmatism was understood. In 1827, an English optician made the first glasses to correct astigmatism.
The development of spectacles and optical glasses is just one part of optometry; significant discoveries in the 19th century led to the creation of optometry as a profession. For example, in 1864, a Dutch medical scientist published “Anomalies of Refraction and Accommodation of the Eye” which was the first paper explaining hypermetropia and presbyopia.
After centuries of discoveries, the first college of optometry in the United States was established in Illinois in 1872. The American Optometric Association was created in 1922. Since then, advancements in science and technology have pushed the field forward.
What is an optometrist?
An optometrist is a doctor who has earned the Doctor of Optometry degree (OD). Optometrists are primary health care specialists trained to examine defects in vision, ocular injuries, ocular diseases, and problems with general health that may affect the eyes like diabetes and hypertension. optometrists offer clinical advice and can prescribe for glasses and contacts.
Optometrists must complete a four-year degree in sciences and four years of post-graduate professional training in optometry school.
When should I see an optometrist?
Visiting an optometrist for regular eye exams is always a good idea. The eye’s health is changing with age and refractive errors as well as many eye conditions can have no symptoms in the early stages. However, when experiencing symptoms such as;
- Frequent headaches
- Blurred vision
- Struggling to see things up close
- Double vision
- Difficulty seeing at night
- Constantly squinting
- Seeing halos of lights, floaters or being very sensitive to light
- Feeling tired with no reason
It is a good idea to go to see an optometrist. They can be signs of refractive errors or other eye conditions. For symptoms such as pain in the eye or complete loss of vision, it is best to contact an ophthalmologist as it can be a medical emergency.
Examples of eye diseases treated by optometrists
Keratoconus is a progressive ocular disease in which the normally spherical cornea begins to thin creating a dome shape that bulges outward like a cone. The cone deflects light as it enters the eye causing sensitivity to light, blurred vision, and large changes to the patient’s refractive error. Keratoconus is an autosomal dominant condition that can run in families.
Keratoconus risk factors:
- Family History. Patients who have had parents or family members with keratoconus or systemic disorders such as Down syndrome have a higher risk to develop keratoconus in their lifetime.
- Chronic eye inflammation. Having chronic inflammation from allergies and irritants may increase the risk of developing keratoconus.
- Eye rubbing. People who always rub their eyes rubbing have more chances to develop keratoconus.
- Age. Keratoconus is generally diagnosed at an early age, during teenagehood.
In the early stages, keratoconus often causes a minor blurring of the vision. The symptoms look like the symptoms of refractive errors. When the disease progresses, vision problems appear. Far and near vision becomes impaired, night vision usually becomes poor. Patients may have an impoverished vision in only one eye as keratoconus usually develops on an eye or the other. Symptoms also include sensitivity to bright light and eye strain. Keratoconus is normally painless.
To diagnose keratoconus, your eye doctor will start by looking at your family history and conduct eye tests to get more details on the shape of your cornea. Diagnosis includes:
- Eye refraction – Your eye doctor will use optical tools to determine your vision’s health and check for any vision problems.
- Slit-lamp examination – In this test, a vertical beam of light and a low-powered microscope are used to view the eye. Your eye doctor evaluates the shape of your cornea and potential problems in your eye.
- Keratometry – Your eye doctor makes a circle of light on your cornea to measure the reflection and see the basic shape of your cornea.
- Computerized corneal mapping – This is a photographic test that creates a detailed map of the cornea. It can detect early signs of keratoconus.
Keratoconus treatment depends on the severity of the disease. The goal of treating keratoconus is to slow the progression of the disease and improving vision. Mild to moderate keratoconus can be treated with prescription glasses and contact lenses. This can work very well if the cornea becomes stable.
If it becomes to difficult to wear glasses or contact lenses, a surgery called cornea transplant might be necessary.
Refractive errors mean that the shape of an eye does not bend light correctly upon entering the eye resulting in blurred images. This can be easily addressed with either glasses or contacts. The main refractive errors are myopia, hyperopia, astigmatism, and presbyopia.
Myopia or nearsightedness makes far objects look blurry. This happens either when there are problems with the shape of the cornea or the lens. It also happens when the eyeball grows too long from front to back. All these conditions make the light focus in front of the retina while the normal eye has light focusing on the retina.
Myopia usually starts at an early age between 6 and 14 years old. In case of severe myopia, the risk of other eye conditions increases.
Hyperopia or farsightedness makes nearby objects look blurry. As opposite to myopia, hypertropia happens when the eyeball grows too short from front to back. It can also happen if there are problems with the shape of the cornea or lens. With all these issues, the light focuses behind the retina instead of on the retina.
Hyperopia appears most of the time at birth.
Astigmatism can make nearby or far away objects look blurry or distorted. Like myopia and hyperopia, this condition happens when the cornea or lens has a different shape than normal. It makes light going to a different position when it enters the eye.
Astigmatism is usually accompanied by another refractive error such as myopia or hyperopia. People are either born with it or develop it in their youth.
Presbyopia touches middle-aged and older adults. It makes it harder to see things nearby. Aging changes the lens in the eyes, it becomes less flexible, and light is not focusing properly on the retina.
Presbyopia touches everyone. It usually happens after 45 years old.
- Blurry vision
- Double vision
- Hazy vision
- Seeing a glare or halo around bright lights
- Sore or tired eyes
- Trouble focusing when reading or looking at a computer
Sometimes patients do not notice the symptoms of a refractive error. That is why it is important to a get regular eye exam. It allows patients to have the best vision possible and fix symptoms such as not being able to focus. This kind of symptoms can feel natural.
When a patient is diagnosed with a refractive error, he or she should keep having regular eye exams as refractive errors evolve and prescriptions need to be updated.
Your eye doctor checks for refractive errors during a comprehensive eye exam. Your doctor simply asks you to read letter charts and measures the results to determine if corrective eyeglasses and contact lenses are needed.
Treatment includes eyeglasses and contact lenses. Sometimes laser surgery (LASIK) can be performed to change the shape of the cornea and fix the refractive error.
MGD or Meibomian gland dysfunction is a blockage of the meibomian glands, located at the base of your eyelashes. MGD is a common eye condition but many people do not notice they have it.
The tiny meibomian glands inside the eyelid create an oil named meibum. This oil, water, and mucus all together create tears, which keep your eyes moist. Meibum keeps the water layer on the eye surface from drying quickly.
Changes in oil quality or glands can lead to Meibomian gland dysfunction.
There are several risk factors identified with MGD. Age plays a part as the number of meibomian glands goes down over time. Ethnicity may also impact your chance to get MGD; Asian people are about three times more likely to get MGD than people from European ancestry.
Wearing contact lenses, the use of glaucoma medications, having high cholesterol, allergic conjunctivitis, lower androgen levels, rosacea, and Sjogren’s syndrome have all been associated with MGD.
In the early stages, MGD might not give any symptoms. As the disease progresses your eyes have less oil or poor quality oil which can make the eyes burn, itch, irritate, or dry. The inflamed eyelid can be red and it can feel like you have sand in the eye. Having the eyelid’s inner rim uneven or rough is also a common sign of MGD.
MGD does not have a single defined aspect. For this reason, your eye doctor looks at your eyelids in detail to inspect the tiny glands. Your doctor can also use Schrimer’s test to check if you make enough tears. Other techniques allow eye specialists to measure the quality of the meibum and how fast the tears evaporate.
To treat advanced MGD your doctor can prescribe eye drops, spray, creams, or pill medications such as:
- Antibiotics for infections
- Cyclosporine for the immune system
- Steroid for inflammation
Your eye doctor can also help improve the symptoms in office with special equipment. If your eye doctor prescribes medications for MGD, it is important to stick to the treatment to reverse MGD or improve symptoms.
Examples of services offered by optometrists
Myopic control aims to slow the progression of nearsightedness in children. Our optometrists can help curb your kids’ myopia starting as early as age 7 and up.
Myopic control is important as it can reduce the risk of other eye conditions. Patients with high myopia (a severe form of myopia) are prone to develop glaucoma, cataracts, retinal detachment, and even blindness.
There are four types of myopic control treatments: Atropine eye drops, multifocal contact lenses, multifocal eyeglasses, and orthokeratology (ortho-k).
Atropine Eye Drops
Atropine eye drops are used to fight eye inflammation and reduce pain. They help with fatigue associated with focusing by limiting the eye’s ability to automatically change focus.
Atropine reduces the progression of myopia for children. It is the best way to control myopia. It can reduce myopia progression by up to 77 percent.
Multifocal Contact Lenses
Multifocal contact lenses or eyeglasses provide clear vision at all distances for people who live with refractive errors. Those contact lenses and eyeglasses are also used to slow the progression of myopia in children. Children who wear multifocal lenses every day have around 50% reduction in the progression of myopia.
Orthokeratology is known as corneal reshaping lenses. Those contact lenses are designed to be worn exclusively at night while sleeping. It creates a temporary correction strong enough that corrective glasses are not needed during the day.
Children age 6 to 10 who wear ortho-k contact lenses have an eyeball length reduced by 43 percent. Which is a key point to fight myopia.
Amniotic stem cells are a mixture of cells obtained from the amniotic fluid and amniotic membrane. They are mostly composed of collagen types IV and VII. The cells can develop into many tissues such as skin, cartilage, cardiac tissue, nerves, muscle, and bone.
Those cells have been used for quite a time to contribute to the healing process in medicine. Eye care professionals started using them a decade ago. It has shown incredible results to heal the cornea on some patients. The amniotic stem cells’ composition is very close to the cornea and conjunctiva compositions. They promote cellular growth, are anti-inflammatory, and promote a healthy environment for the eye’s wounds to heal.
Amniotic stem cells have shown great results to heal various types of ocular surface diseases. It can heal severe dry eyes with superficial punctate keratitis, neurotrophic ulcers such as those associated with diabetes or viruses like herpes and chemical burns to the eyes.
The cells have successfully healed eye corneal conditions when no other medicine worked. As a result, we could think that the use of these cells is widespread but only 1% of optometrists in the USA reported using them.
The procedure is pretty simple. The patients seat in the exam chair and look down. The optometrist inserts the amniotic cells on the cornea. Once the application is done, the patients should be seen often until the cornea is healed. The amniotic stem cell ring holder should be removed once the cells dissolve.
For this exam, doctors place drops in the patients’ eyes to dilate the pupils allowing them to examine the overall health inside of the eye, especially the retinal vessels in the periphery.
In this eye exam, our doctors look through a magnifying glass with a bright light to be able to see the back of the eye and check for its health. The doctors will be able to see parts that can be damaged by diabetes such as:
- Blood vessels in the eyes
- The back of the eye
- The optic nerve area
Why going to a diabetic eye exam?
Anyone who lives with diabetes produces less insulin hormone which elevates levels of glucose (sugar) in the blood. Having increased blood sugar levels increase the risk of eye conditions. It can lead to cataracts, glaucoma, and diabetic retinopathy.
A diabetic eye exam is the only way to diagnose diabetic retinopathy, which is the most common cause of vision loss among people with diabetes. Chronic diabetes usually damages the small blood vessels in the retina and the back of the eye, which causes diabetic retinopathy.
Because the longer someone lives with diabetes the greater is the chance of developing diabetic retinopathy, it is important to do regular diabetic eye exams. Diagnose diabetic retinopathy early is the best way to control early symptoms and take appropriate measures to treat it.
If you have diabetes, you are encouraged to contact your eye care provider and get a diabetic eye exam.
After a diabetic eye exam
As you had eye drops to dilate your eye during the diabetic eye exam, your vision will be blurry for about six hours. It will be harder to focus on activities requiring near vision such as reading.
When pupils are dilated, sunlight can be more damaging. You should wear sunglasses with UV protection until the effects of the eye drops dissipate.
Prescriptions refer to written authorizations for a patient to purchase medications to treat specific conditions. For a prescription to be legally accepted, it needs to be written by an authorized physician, dentist, psychiatrist, ophthalmologist, optometrist, and any other doctors officially recognized by law.
Every medical profession has its own rules and limits with what kind of prescriptions they can provide.
Optometrists are state-licensed medical professionals who specialize in eye health. Optometrists examine, diagnose, and treat various eye conditions such as diseases, injuries, and disorders. They can prescribe eyeglasses and contact lenses when necessary. For example, they are the ones who diagnose refractive errors (nearsightedness, farsightedness, presbyopia, astigmatism etc.) and prescribe corrective contact lenses and eyeglasses.
They are also authorized to prescribe ophthalmic drops to treat conditions such as glaucoma.
Once your optometrist has written your prescription, the opticians manage what happens next. Opticians work in a lab and use manufacturing machines to cut lenses based on optometrists’ prescriptions.
What to remember?
Optometrists are eye specialists who can diagnose and treat refractive errors and many eye conditions. Regular eye exams with an optometrist are important as many eye conditions do not have symptoms in their early stage.