What is an Ophthalmologist?
An ophthalmologist is a physician who specializes in diseases that affect the eyeball and the orbit, which is the eye socket in the skull and the muscles connecting the socket to the eye. The word comes from the Greek words ophthalmos (?φθαλμ?ς), meaning eye, and -logia (-λoγ?α), meaning the study of.
There is a difference between an ophthalmologist and an optometrist in the level of training they receive and the level of care they are allowed to provide. An optometrist can prescribe corrective lenses, provide medication for eye diseases and participate in preoperative and post-operative care for eye surgeries, but they cannot perform the surgeries themselves. Only ophthalmologists are allowed to perform eye surgeries, along with all other tests and therapies for eye care that an optometrist can provide.
Much like any other medical specialty, an aspiring ophthalmologist must first receive a Bachelor’s degree and complete a set of pre-medical courses. Commonly required courses include Biology, Biochemistry, Physics and Anatomy. Following the completion of a Bachelor’s degree is four years of medical school, which will consist of two years of lecture and laboratory work and two years of clinical duty, where students will work closely with physicians who provide guidance and counsel. Upon graduation from medical school, the aspiring ophthalmologist must then pass a licensure exam to be able to apply for ophthalmology internships.
The internship allows the medical student to gain the knowledge to specialize in ophthalmology. Internships generally last for one year and once completed, the aspiring ophthalmologist moves on to a residency program. This allows the aspiring ophthalmologist to learn about the subspecialties of ophthalmology. A residency program lasts 3 years at a minimum and can last up to 8 years. Once completed, the ophthalmologist may opt to join in fellowships to receive further training for professional development.
Roles and Responsibilities
Ophthalmologists are responsible for the diagnosis and treatment of eye diseases. An ophthalmologist is capable of treating eye conditions in patients of all ages, including babies and the elderly. They operate diagnostic equipment, such as ophthalmoscopes and slit lamps, and provide correctives treatments like the prescription of corrective lenses, medicines and surgical operations.
Surgical operations require the use of specific equipment, such as operating microscopes and lasers. Ophthalmologists can work in outpatient environments, in the operating room, in laser eye surgery clinics and, in some cases, in wards. Ophthalmologists may also work in multidisciplinary teams, generally with neurologists, eye-nose-throat surgeons and/or pediatricians.
The first known mention of eye surgery is dated around 1754 B.C.E., in the Code of Hammurabi from Babylon. In it is a description of rewards and penalties for the success of failure of eye surgeries. Specifically:
At this point in time, the practice of medicine was in the hands of priests. As such, surgeries were performed with magic incantations. Babylonian society, according to Greek historian Herodotus, had no medical practitioners. People who suffered from diseases were sent to wait in marketplaces, where other townspeople assessed the disease and recalled if they had encountered or suffered the same disease already. If they have, they are tasked with providing the diseased with advice regarding treatment.
The next mention of ophthalmology comes from the Ebers Papyrus from Egypt, named after German Egyptologist Georg Ebers. An entire section of the Ebers Papyrus is dedicated to the diagnosis and superstitious treatment of a variety of eye diseases. The papyrus had descriptions for a number of ailments:
The treatment of such diseases was still designated to priests at that time, and thus had corresponding magical incantations as treatment. While Egypt had made significant advances in the diagnosis of eye diseases, it was most likely a result of centuries of observation and practice but the common belief for the source of diseases remained to be demons. This explains why treatment remained to be superstitious.
The first signs of a departure from superstitious treatment is from the Ayurveda and the Uttar-tantra, both of which are credited to Susruta, the father of Indian Surgery. Both documents are part of the Susruta Samhita and are dated at around 800 B.C.E. The cataract is described in the Ayurveda as ‘Lingnash’, a combination of ‘Linga’, meaning ‘visual power’, and ‘nash’, meaning ‘destruction’. The Uttar-tantra describes 8 types of cataract. Also included is a detailed description of the surgical procedures for the treatment of cataracts. A probe was used to puncture a specific part of the eye and the probe is then used to scrape the papillary area of the lens until it becomes clear. Once the lens becomes clear, the probe is gently removed. When done perfectly, the entire operation is recorded to be painless. This procedure is commonly called ‘couching’ by many scholars.
It is impossible to discuss the history of medicine without mentioning Hippocrates. While he is called the Father of Medicine for his contributions in the separation between medical practice and superstition, he impacted ophthalmology negatively. His knowledge of the nature and structure of the eye was not advanced compared to the writings of the Egyptians. His focus on the four humours (blood, mucous, yellow bile, and black bile) made his treatment of eye diseases ineffective.
Examples of treatments used at the time are restrictions in diet, hot foot baths, the drawing of blood, cauterization of nearby blood vessels, and the drilling of a hole in the skull. His understanding of eye disease was essentially incorrect and thus his treatment of eye diseases was largely ineffective.
The next writings in the subject of ophthalmology come from Rufus of Ephesus, Celsus, and Galen.
Rufus advanced the knowledge of the eye’s anatomy. He noted that the eye had two chambers, one between the lens and the retina that is filled with viscous fluid and the other from the cornea to the lens that is filled with water. Celsus put forth a detailed description of the couching method as a treatment for cataracts. Galen’s work described the anatomy of the cornea, the lens and the optic nerves. After Galen’s work, very little was added regarding the anatomy of the eye until the beginning of the 16th century, more than a millennium later. There could have been many other works related to the subject of ophthalmology, but those works have burned down with the Library of Alexandria.
The burning of the Library of Alexandria marked the height of the Arabian conquest of Europe and some Greek writings on ophthalmology were translated first into Syriac and then Arabic. The surgical procedures known to Galen and his contemporaries were perfected by the Arabs, but they did not venture into new research in favor of tradition. Thus, while there was much to say in the improvement of ophthalmology as a medical practice, very little new theory was made. Whatever new knowledge was stumbled upon was forcibly restructured to conform with traditional knowledge.
After the Arabian Renaissance ended, the movement in the development in ophthalmology continued in Western Europe. Constantinus Africanus, a traveling monk, translated Arabic works into Latin in the 11th century. He adopted the name ‘cataract’ and his work allowed research and study efforts in Western Europe to flourish. Peter the Spaniard, who would later be known as Pope John XXI, wrote a work on the hygiene of the eye. Benevenutus Grassus summarized the Greek and Arabian knowledge in ophthalmology into a single work. The contagious properties of ophthalmia, an inflammation of the eye, was also put forth by John Yperman.
Despite all this, little advance was made in the subject of surgical treatment of eye diseases. Couching as a treatment for cataracts could be done by anyone and little attention was given to eye diseases by surgeons of the time.
The next notable name for ophthalmology is Roger Bacon, whose work on optics and corrective lenses is still in effect at present. While the idea of using lenses was not originally his, he was the first to recognize the application of lenses to correct the eyesight of the elderly and those with weak eyesight. In his ‘Opus Magnus’ written in 1268, he presented his research on optics and lenses. In it, he recommended the use of a convex lenses to correct the eyesight of the elderly or to magnify text on a page. His ideas were passed on to Alexander de Spina, a Dominican monk at Pisa, who is credited as the inventor of spectacles.
Knowledge of the anatomy of the eye had not moved forward until the year 1500, when Leonardo da Vinci discovered that the retina was the essential organ of vision, instead of the lens which was common belief during the time of Galen. He also asserted the nature of the ‘camera obscura’, the pinhole image, as it relates to the human eye. The ‘camera obscura’ is a phenomenon described by light entering a pinhole opening, like a pupil, through a biconvex lens, such as the lens of the human eye, and a surface where the image is formed, like the retina.
The next significant movement in surgical ophthalmology happened in 1748. French ophthalmologist Jacques Daviel published a paper on a treatment method for cataracts that was superior to couching where he would remove the formed opaque lens through the anterior chamber. This method is now called extracapsular cataract extraction and is now one of two surgical procedures used to treat cataracts.
Selected Topics on Modern Ophthalmology
Visual Development and Age
Much like many other parts of the body, the eyes develop steadily from childbirth to middle age and decline during old age. At birth, a baby’s eyes generally cannot move their eyes between two images. Their focus is also very limited to about 8 to 10 inches from their face. Vision rapidly improves within the first few weeks of life as the eyes begin to coordinate with each other. Following moving objects becomes possible and hand-eye coordination develops as babies begin to reach out for things of interest. For the first two months, a baby’s eyes may become crossed. This is normal. An evaluation may be needed if the eyes begin to turn in or out constantly.
At five months, babies begin to develop depth perception, which allows them to perceive objects in three dimensional space. At eight months or when a baby starts crawling, the baby develops hand-eye-body-foot coordination. A baby’s ability to see, focus on things, and coordinate the eyes with the body develops when the baby is exposed to stimuli and allowed to roam. These should therefore be encouraged.
Visual problems in infants is rare. Blocked tear ducts cause excessive tearing. Constant eye turning may be a sign of poor muscle control. An eye infection causes red eyelids. Extreme sensitivity to light may be a sign of elevated pressure in the eye. A white pupil could be a sign of eye cancer. Any of these symptoms require immediate medical attention.
Visual development improves and stabilizes until age 40, where it starts to decline again. The effects of the decline become more apparent at age 60, where major visual problems begin to naturally occur. As people age, the lens becomes stiffer, making focusing on closer objects more difficult. The lens becomes denser, which makes seeing in dim light difficult. The pupil reacts slower to changes in light. The lens yellows due to years of exposure to ultraviolet light, dust and wind, causing color perception to change. Nerve cells in the eye decreases, making depth perception less accurate. The eyes begin producing less fluid, making them feel dry.
Presbyopia occurs when the eyes become stiffer. Presbyopia literally means old eyes, from the Latin presbus, meaning old man, and ops, meaning eye. Presbyopia makes seeing things closer than 2 feet to the eyes more difficult. It is commonly treated by over-the-counter reading glasses, improved lenses for those who already wear glasses, or refractive surgery. Refractive surgery reshapes the cornea for far vision for one eye and close up vision for the other eye.
Dry eye, as the name implies, is the phenomenon wherein the eye begins to produce less fluid. The condition is more common for pregnant women and women who enter menopause, as the hormonal changes in their bodies can impair the eye’s tear production. People who suffer from dry eye are at an increased risk of blepharitis, which is the collection of bacteria and oily flakes at the base of the eyelashes. There are many simple things a person can do to combat dry eye. One may simply blink more to reapply a protective oil coating over the eye, eat more nuts and fish, humidify a room or move away from wind. Blepharitis is more complex, as it has no known cure. Its symptoms can be managed with warm compresses, eyelid scrubs, eye drops or antibiotics.
The Macula and Age Related Macular Degeneration(AMD)
The macula is a part of the retina. It is a set of light sensitive cells that provide sharp central vision. When it is damaged, the center portion of vision becomes blurry, dark or distorted, regardless of distance. Side vision, called peripheral vision, remains the same.
There are two type of AMD: dry and wet. Dry AMD is more common. The macula naturally gets thinner with age. This weakening happens slowly. There is no known way to treat Dry AMD yet. Those who suffer from Dry AMD are recommended to take nutritional supplements to try and slow down the degeneration.
Wet AMD is characterized by the growth of new vessels under the retina. These new vessels leak blood and other fluids, causing damage to the macula. Vision loss is much faster in this case. One way to treat Wet AMD is with drugs that suppress the vascular endothelial growth factor, or anti-VEGF drugs. These drugs are injected into the eye using a very long, thin needle. This treatment is repeated over multiple months. Laser therapies may also be used to seal or destroy new blood vessels in the eye.
While age is a definite factor for AMD, hence the name, there are many other risk factors for it. These are: a diet high in saturated fat, obesity, cigarette smoking, and genetics.
Cataracts are described as a clouding of the lens, reducing a painless loss of vision. It is the leading cause of blindness worldwide. Cataracts usually develop without a cause, but aging has been linked to the occurrence of cataracts. Other risk factors include alcoholism, diabetes, eye injuries, exposure to x-rays or to certain drugs, poor nutrition, and smoking. Babies may be born with cataracts and children may develop cataracts from eye injuries. Its usual development is slow. Early symptoms may include glare around lights, blurred vision, and difficulty in seeing contrast. In most cases, cataracts do not cause pain. In the event that cataracts swell, it could exert some pressure in the eye, which may be painful. This is called glaucoma.
The many advances in medical technologies allow physicians to respond to cataracts with less risky methods than couching, the side effects of which could be worse than the cataract itself. Current treatments include corrective lenses and surgery. Surgery is the only known cure for cataracts. There is no advantage to having surgery early in the development of a cataract compared to its later stages. Surgery is performed with a small incision in the eye. Ultrasound breaks the cataract into small pieces which can be removed out of the lens capsule. Once completed, the ophthalmologist inserts a plastic or silicone lens into the lens capsule. If it cannot be placed safely, the patient must wear thick glasses or contact lenses when the cataract has been removed. The procedure generally takes about 30 minutes.
Diabetic retinopathy commonly occurs when a person has diabetes, hence the name. High blood sugar levels may cause damage to the blood vessels in the retina. Blood vessels may leak or close, or new blood vessels may grow around the area abnormally. All three can cause blindness if left untreated.
Diabetic retinopathy progresses through four stages. Mild nonproliferative retinopathy is characterized by small balloon-like swellings in the blood vessels of the retina. These swellings, called microaneurysms, leak fluid into the retina, causing damage. As it progresses, it enters the moderate nonproliferative retinopathy stage. Blood vessels connected to the retina begin to swell or become unable to transport blood. Severe nonproliferative retinopathy follows. As more blood vessels become blocked, growth factors signal the need for new blood vessels. When new blood vessels form, the disease enters the proliferative diabetic retinopathy(PDR) stage. These new blood vessels form along the retina and the vitreous gel, the fluid that fills the eye. These vessels are weaker and are prone to damage. When damaged and regenerated, these vessels form scar tissue, which can cause the retina to detach from underlying tissue. This causes permanent blindness.
Any person who suffers from diabetes, both Types 1 and 2, are at risk of having diabetic retinopathy. The longer they have diabetes, the higher the risk becomes. Diabetic retinopathy usually has no early symptoms until vision impairment. Bleeding from blood vessels in the retina may cause floating spots to appear in vision, but these spots clear up in time.
Because diabetic retinopathy has no early symptoms, people who suffer from diabetes are recommended to have at least one comprehensive eye exam every year. Women with diabetes who become pregnant should have an exam immediately. People who suffer from diabetic retinopathy should have more exams done per year or risk irreversible blindness.
Diabetic macular edema (DME) is a condition that goes along with diabetic retinopathy. DME can develop at any point in the four stages of diabetic retinopathy’s development, more commonly occurring as the diabetic retinopathy progresses. This causes damage to the macular area of the retina, thus causing the central area of vision to blur and/or dim.
Similar to AMD, anti-VEGF drugs and laser therapies may be used to combat DME. The methods used here are similar to those used in AMD. Corticosteroids may also be used to suppress DME. Corticosteroids are applied with implants that release sustained doses within the eye. Corticosteroids increase the risk of cataracts and glaucoma. Constant monitoring is therefore needed to avoid complications.
Studies have shown that anti-VGF drugs are also effective in slowing the progression of diabetic retinopathy in all stages. When diabetic retinopathy continues to progress, panretinal laser surgery may be performed. This is done with 1000 to 2000 small laser burns on the retina away from the macula. This improves and preserves central vision, but may damage peripheral vision, night vision and the perception of color. A vitrectomy may also be performed as a treatment for PDR, when blood vessels leak too heavily into the vitreous. This is the surgical removal of the vitreous gel in the eye. The vitreous gel is replaced with a clear salt solution to maintain the internal pressure of the eye. The same instruments used in a vitrectomy may also remove scar tissue or repair a damaged retina.
When fluid builds up in the eye, the increased pressure may cause damage to the optic nerve. This is called glaucoma. Left untreated, glaucoma can cause blindness.
There are two major types of glaucoma. Primary open-angle glaucoma is a slow buildup of pressure caused by the eye’s impaired ability to drain fluids. This type is painless and causes no vision impairment at first. Angle-closure glaucoma occurs when the iris is too close to the eye’s drainage angle. This causes a buildup of pressure in the eye. Many cases of angle-closure glaucoma develop slowly, called chronic angle-closure glaucoma. When the drainage angle is completely blocked, an acute attack occurs, which causes rapid pressure buildup in the eye. Symptoms of acute attacks include blurry vision, severe eye pain, headache, nausea and vomiting, and rainbow-colored halos around lights. Risk factors for glaucoma include age (over 40), genetics, eye injuries, corneas that are thin at the center, thinning optic nerves, and diabetes. The intake of certain drugs also increases the risk of glaucoma.
The treatment of glaucoma involves medication, laser surgery or operating room surgery. Medication in the form of eye drops may be used to reduce eye pressure by reducing the amount of fluid produced in the eye or helping the fluid flow better through the drainage angle. Side effects of these medications include blurred vision, changes in pulse, energy level and/or breathing, dry mouth, eyelash growth, or irritation around the eyes. Laser surgeries involve the improvement of the drainage angle for open-angle glaucoma, a process called called trabeculoplasty, or the puncturing of a hole in the iris for angle-closure glaucoma, an operation called iridotomy. Operating room surgeries include the insertion of a drainage tube in the eye or the creation of a flap in the white of the eye and a filtration area under the upper eyelid. The fluids of the eye drain through the flap into the filtration area and absorbed by the tissue around the eye. This process is called trabeculectomy.
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