Is refractive surgery safe today? What should someone who wishes to undergo such a procedure know? Can presbyopia be corrected? These are questions that trouble people with vision problems and decide to undergo laser eye surgery. Ophthalmologist surgeon George Chronopoulos answers these questions.
Refractive surgery has brought a revolution in myopia, hyperopia and astigmatism correction. We are already in the third decade of laser use and we can really observe that precision and safety are already here. With the use of this impressive technology, we can forever eliminate our dependence on corrective glasses or contact lenses..
There are two methods of effective correction of high or low degrees of myopia, hyperopia and astigmatism: PRK and LASIK. The difference between these two methods lies in the fact that, in the first, the correction occurs on the surface of the cornea, while in the second in its interior. In PRK there is some minor discomfort the first 2-3 days, while in LASIK the discomfort is insignificant and eyesight restoration happens almost immediately, on the very first day. The final result is the same in both cases.
First of all, we are dealing with a procedure done not only for aesthetic reasons, but therapeutic as well, with which there is a definite change in the way of life. An important role in the patient's decision to do away with glasses and contact lenses plays the trust and relationship between doctor and patient. Equally important is to have thorough preoperative tests, which will tell us if the patient is eligible for a certain procedure.
Detailed and thorough preoperative tests ensure the success of the procedure, Dr. Chronopoulos underlines.
Timewise, the procedure lasts only a few minutes and it is never longer than 5 or 6 minutes for both eyes. The doctor uses local anesthesia and the patient feels no pain. After the procedure it is advisable for the patient to sleep for a couple of hours and to avoid washing his hair with the eyes open, driving on the first day, swimming for the next four weeks and exerting himself for about a week; in any case, he should be in close contact with his doctor. It is important to note that the correction is permanent and in the very few cases where some degrees of the condition remain, then an additional laser procedure can be done to achieve full correction.
Regarding complications, the 25 years of laser use allow us to say that the possibility of serious complications is negligible. Even those rare complications can be treated. We are in a position to say with absolute certainty that the chances of infection from contact lenses are more than the possible complications of refractive surgery.
Presbyopia today is outside the scope of refractive surgery and is the field where the ophthalmologists' interest is focused. The problem lies in the fact that, if we try to correct presbyopia, we unavoidably interfere with distant vision as well, which results in the patient's not having good eyesight in the distance; so we enter a cycle of procedures without end and with no effective result for the patient. Therefore, as things stand, says Dr. Chronopoulos, we are not yet in a position to say that we have found a solution to correct presbyopia. We would like to believe that technology and ongoing scientific research will lead at some point to a solution for the very annoying problem with presbyopia, that is indeed troubling for a great many patients.
Published in the newspaper
Eleftherotypia
on 3 March 2007
Refractive surgery has brought a revolution in myopia, hyperopia and astigmatism correction. We are already in the third decade of laser use and we can really observe that precision and safety are already here.
Refractive surgery has brought a revolution in myopia, hyperopia and astigmatism correction. We are already in the third decade of laser use and we can really observe that precision and safety are already here. With the use of this remarkable technology, we can eliminate our dependence on corrective glasses or contact lenses for good. There are two methods of effective correction of low or high degrees of myopia, hyperopia and astigmatism: PRK and LASIK. The difference between these two methods lies on the fact that, in the first, the correction occurs on the surface of the cornea, while in the second in its interior. In PRK there is some minor discomfort the first 2-3 days, while in LASIK the discomfort is insignificant and eyesight restoration happens almost immediately, on the very first day. The final result is the same in both cases.
First of all, we are dealing with a procedure performed not only for aesthetic reasons, but therapeutic as well, with which there is a definite change in the way of life. An important role in the patient's decision to do away with glasses and contact lenses plays the trust and relationship between doctor and patient. Equally important is to have thorough preoperative tests, which will tell us if the patient is eligible for a certain procedure. Detailed and thorough preoperative tests ensure the success of the procedure. Timewise, the procedure lasts only a few minutes and it is never longer than 5 or 6 minutes for both eyes. The doctor uses local anesthesia and the patient feels no pain. It is important to note that the correction is permanent and in the very few cases where some degrees of the condition remain, then an additional laser procedure can be done to achieve full correction. An important role in the patient's decision to do away with glasses and contact lenses has the trust and relationship between doctor and patient. The 25 years of laser use allow us to say that the possibility of serious complications is negligible. Even those rare complications can be treated. We are in a position to say with absolute certainty that the chances of infection from contact lenses are more than the possible complications of refractive surgery.
Presbyopia today is outside the scope of refractive surgery and is the field where the ophthalmologists' interest is focused. The problem lies in the fact that, if we try to correct presbyopia, we unavoidably interfere with distant vision as well, which results in the patient's not having good eyesight in the distance; so we enter a cycle of procedures without end and with no effective result for the patient. Therefore, as things stand, we are not yet in a position to say that we have found a solution to correct presbyopia.
Published in the newspaper
To Paraskinio
on 1 April 2010
Problems caused by computers are the second most frequent reason for young healthy people to visit their ophthalmologist. What happens to people that use computers for long hours during the day is basically what is called “asthenopia”, that is difficulties in vision. The second problem is of course problems caused by repetitive movements of the fingers and of the muscles of the arm.
The consequences of computers on vision and the eyes are still under general observation, but any kind of permanent damage hasn't yet been verified.
More than 50% of computer users suffer from eye fatigue, headaches and blurry vision. These symptoms sometimes affect the person's general health, creating a sense of fatigue, which leads to decreased work performance.
There are also some indications that, in rare cases, people working long hours in front of a computer, face an increased risk for glaucoma.
When we are viewing a computer screen, what happens is that we lose depth perception, i.e. stereopsis, and our focus is always on a single point. Also, our eye convergence (what happens when we're looking at something really close) is continuously hyperactive and the frequency of blinking is decreased. This is completely different from reading a printed page, since most computer monitors, especially those with a CRT, do not emit a single image, but an image that passes frame by frame and our brain connects it so we can see a continuous image; it is an image with diffused light and has very different contrast and clarity. After using a computer for many hours, what happens is that the cones, the cells we use to perceive colors, are always hyperactive and the image from the cones' hyperactivity stays in our brain, despite the change of image on the computer screen. This is called “after effect” or McCollough effect and sometimes color perception is reversed.
Things that worry us with computer use is if we are exposed to radiation and UV radiation and how much, and if this can potentially lead to cataract. It should be noted that there is proof that the radiation we receive, especially when it comes to UV radiation, is less than that of a fluorescent bulb, so there is no dangerous radiation for the eye and no proof that this can lead to cataract.
Headache during and after PC use
Pain between the eyes
Dry and/or irritated eyes
Blurry vision
Slow focus during screen use
After long hours of PC use there is difficulty in viewing distant objects
Occasional diplopia
Poor color perception
Pain in the neck and the shoulders
Back pain
Fatigue, maybe even pain, of the hands and wrists
Decreased work performance, frequent mistakes, fatigue
The computer monitor should be on a lower level than the eyes.
The keyboard should be in such a position that the bottom of our arms and wrists is parallel to the ground.
The seat should be adjustable, so it can cater to the user's needs.
The thighs, like the arms, should be parallel to the ground.
Contrast and brightness of the screen should be adjusted to the desired setting, so that the user feels comfortable and doesn't tire his eyes.
The lighting in the room must be three times brighter than the monitor.
A screen filter should be used.
It is important to work on a big screen, so it isn't tiring to read or write a text.
Στην οθόνη δεν πρέπει να αντανακλά φώς από παράθυρο ή άλλη φωτεινή πηγή.
The screen shouldn't reflect light from a window or another light source.
It is necessary to clean your screen regularly.
Adjust the font size on your screen, choosing a setting which is comfortable, if the software gives you that choice.
Adjust brightness and contrast on your screen.
People who use computers all the time may experience some refractive anomalies, like slight myopia, slight astigmatism, slight hyperopia; if this is corrected with the use of glasses or contact lenses, it will help them use these devices easier.
Use of artificial tears may help with xerophthalmia that long hours in front of the PC might cause, due to the decrease in blinking speed and frequency; proper moisturizing of the atmosphere, in which the person works and uses the PC, may also help.
The most important thing of all is to have short and frequent breaks of 2-3 minutes every 15-20 minutes of work or 5 minutes for every 30 minutes or 10 minutes for every hour.
Myopia, hyperopia and astigmatism correction, which aims at improving vision and reduce or even eliminate dependence on glasses and contact lenses, has been possible for several years, with various surgical techniques and is an integral part of refractive surgery.
The strides that have been made in biomedical technologies, lasers and ophthalmology allow us today to correct these refractive anomalies and stop being dependent on glasses and contact lenses. The results are impressive. The procedure is done fast, painlessly and the patient leaves the clinic immediately and without bandages.
Refractive anomalies or ametropias are myopia, hyperopia and astigmatism: Myopia is the condition in which distant vision is affected when the axial length of the eye is big in comparison to the curvature and the refractive strength of the cornea. Light rays that enter the eye focus in front of the retina, which results in a blurry visual image, when the myopic person focuses on relatively distant objects. On the contrary, close objects, as a rule, remain clear. In hyperopia, it is close vision that is mainly affected, but distant vision can as well, because the axial length of the eye is small in relation to the curvature and the refractive strength of the cornea. The light rays focus behind the retina which results in an effort by the hyperopic person to continually adjust his vision, which, after some time, is no longer feasible. In astigmatism the cornea is not round but elliptical, light focuses on many points on the retina, which results in blurry close and distant vision. Astigmatism can coexist both with myopia and hyperopia.
The traditional way to treat refractive abnormalities is with glasses and contact lenses. For various reasons, many people do not wish to wear them either because they're tired of the long-term use, or for aesthetic and professional reasons or because they can't tolerate contact lenses (intolerance and allergy to contact lenses or, more usually, to the chemical cleaning fluids; giant papillary conjunctivitis). For these people there is an indication to undergo refractive surgery. In theory every person with a refractive abnormality can undergo such a corrective procedure: -Those who are over 18 years of age and their refraction has remained stable for the past year. -In general, all those who are interested in their appearance and want good quality of vision without dependence on glasses or contact lenses.
For the proper treatment of refractive abnormalities, thorough preoperative tests are needed. The most important tests, besides a general ophthalmological examination, refraction and keratometry, are corneal topography, pachymetry and the cell measurement of the corneal endothelial. Latest developments in topography devices allow as to examine in significant detail the condition of the anterior and the posterior surface of the cornea. Topography devices such as Pentacam, Orbscan and Wave-Front analyzers have helped enormously to enrich our knowledge on refraction and vision quality, as well as to understand the causes for cases with inexplicably poor vision. Those tests and measurements are of extreme importance, since the results of the procedure depend directly on the consistency and precision of these measurements. It is important to know that in order to have precise results, we should stop wearing contact lenses at least 7 days before the tests and the procedure.
The type of laser used for these procedures (excimer laser) functions by sculpting and giving shape to the corneal surface, so as to eliminate the refractive abnormality. The technique mostly used worldwide today is laser-assisted in situ keratomileusis (LASIK) which is a combination of microsurgery and laser. LASIK is appropriate for myopias from -1.00 up to -12.00 D, depending on the indications. Hyperopia and astigmatism have more restrictions (up to -6 D), but we can interfere to reduce the abnormality if it is larger. The surgeon creates a flap on the cornea and lifts it up like a cap. The laser acts under the surface and on the corneal layer, sculpting its surface without injuring it. The flap closes and the procedure ends. The procedure is done with eye drops and is completely painless. Laser application lasts less than 30 sec and the whole procedure lasts no more than 5 minutes. No protective lens or sutures are needed and there is no pain or discomfort postoperatively.
This way, immediate vision restoration can be achieved (within a few hours) and the patient leaves the clinic without bandages and without needing his glasses. An alternative technique is called photorefractive keratectomy (PRK). In PRK no flap is created; the corneal epithelial is simply removed and the laser is applied directly. At the end of the surgery, a therapeutic contact lens is worn until the epithelial is healed. This technique may be used if the thickness of the cornea does not allow us to perform a LASIK procedure. The corneal condition, the age of the patient, the degrees of the refractive fault, the result of the topography and the pachymetry are, generally, some of the factors that will affect the surgeon's strategy.
It is now generally accepted that the use of lasers has brought impressive results with its aim being to stop the dependence of patients on glasses and corrective lenses. Success is considered if 0 sph & cyl (+/- 0,50 D) is achieved and this can be done today with almost 99% success rate. Technology has made significant strides so that today we can consider this procedure completely successful, reliable and very safe. Additionally, it allows us to know preoperatively who are eligible candidates for the procedure, if we can move on with safety and inform the patients for the possible result. We can now say that this significant increase in the percentage of refractive surgeries is due to the rapid advances of Excimer Lasers, that allow us to correct with precision high degrees of myopia, hyperopia and astigmatism.
After the procedure, it is possible to alter the result (involution) either within the first six months or at any time in the future. This can happen if:
Healing process is very intense for a patient. In this case, it is possible for involution to be observed. This happens in the first 6 months and if it does, we can, after a certain amount of time has passed (and if the remaining thickness is sufficient and certainly in cases not related to corneal ectasia), repeat the laser procedure to correct whatever problem has remained without any additional fees.
Myopia in this particular person is progressive. This means that it can suddenly start increasing, at any time and any age. This would happen anyway, regardless of any laser procedure. The benefit for the person that has a laser eye surgery is that his myopia will start increasing again from 0 degrees or near zero. If, for example, someone had 5 degrees of myopia and, after the surgery, this has decreased to 0.5, then, if after a year his myopia increases by one degree than he will have 1.5 degrees (0.5 remaining plus 1 degree from the increase), while if he hadn't had the surgery his myopia would be 6 degrees (5 he had and 1 degree from the increase). If myopia, therefore, increases after the first 6 months from the surgery, then we are dealing with progressive myopia. In other words, the result is considered permanent if within 6 months from the surgery, no alteration is observed. Every change after this period can be considered genetic information and is treated accordingly.
For more information you can visit our website www.eyeclinic.com.gr/en.
G. Chronopoulos, Ophthalmologist Surgeon
(published in tlife.gr)
A new scientific treatise from Paschalides Medical Publications.
Read the foreword for the Greek Edition written by Dr. G. Chronopoulos.
A few years ago, the phrase “knowledge is power” still retained its originality and freshness. Today it is a belief among all educated people that, especially in issues of health and disease that are lived by everyone every day, albeit unconsciously, this saying holds even more gravity.
Ophthalmic Surgery admittedly possesses a pioneering position in medicine. Impressive achievements in all its branches, but especially Refractive Surgery during the second half of the 20th century, gave it new prestige and affected its course substantially. During the last decade of the century, Refractive Surgery started to accept strong influences from the progress in biomedical sciences and technology, which moves forward with an explosive pace. Rapid advancements in the technology of Excimer lasers, as well as the increasing applications of Femtosecond lasers in the creation of the flap have brought Refractive Surgery to great crossroads and tend to change its physiognomy, to a point that it is unknown what its course will be in the 21st century in which we currently liveTraditional complications such as under-/overcorrections, incomplete, decentered flaps or “button hole” flaps tend towards extinction with the introduction of new pioneering technologies in the practice of corneal surgery. However, the increase of the frequency of refractive surgery created new issues, such as new forms of persistent inflammations, the need to calculate the strength of IOL in cataract surgery after corneal surgery or the loss of endothelial cells, all of which are complications that worry all refractive surgeons in their everyday practice. For these reasons, the doctor's continuous education is more necessary than ever before and needs to be achieved with all available means, like conventions, conferences, round tables and magazines, but also with treatises, where the knowledge given is responsible and crystallized.
This book concerns both the Resident doctor and also the experienced Ophthalmologist. For the former it is a detailed and informative source of knowledge on Refractive Surgery, while for the latter it plays the part of a modern reference book. Its exclusive goal is to provide current and future surgeons with the most recent information on the pathogenesis of possible complications in Refractive Surgery and offer an approach to their prevention and treatment.
The resident, the general ophthalmologist and the surgeon are always in need of approachable and rich in content treatises that are a source of quick reference in a given time, when the doctor considers necessary to bring certain knowledge back to memory. I believe that Jorge L. Ailo and Dimitri T. Azar succeeded in full by avoiding details that are not essential in the development of a surgical issue.
It is a successful and dense presentation of 19 chapters on how to treat the most common and difficult complications, which, in the writers' opinion, but also in the opinion of this foreword's author, belong in that list of subjects whose knowledge is essential for the ophthalmologist, but also for the young surgeon that is learning the art of refractive surgery.
Notable merits are its clarity, its method, its elegance and the rich illustrations of excellent quality.
To translate the individual chapters, colleagues that have dedicated their lives to the service of a certain expertise were recruited, in order for us to give to the beginning of the new century a completely modern treatise of refractive ophthalmic surgery for the first time in a Greek edition. I would like to thank them for the special care they have shown to faithfully translate the text, even if, in some cases, paraphrasing was de factoFinally, I would like to thank the publisher, Mr. P. Paschalides, for his efforts on this complete edition. I am sure that “Treatment of Complications in Refractive Surgery” will gain from its medical readers the recognition and appreciation that an important text deserves and that it will be an especially useful tool of knowledge and, at the same time, an important incentive for further study and deeper research in the world of knowledge.
George Chronopoulos
Consultant Ophthalmic Surgeon
Information on Refractive Surgery
Refractive surgery has brought a revolution in myopia, hyperopia and astigmatism correction. We are already in the third decade of laser use and we can really observe that precision and safety are already here. With the use of this impressive technology, we can forever eliminate our dependence on corrective glasses or contact lenses.
There are two methods of effective correction of high or low degrees of myopia, hyperopia and astigmatism: PRK and LASIK (conventional LASIK, where the creation of the flap is done with a mechanical microkeratome and FEMTO-LASIK, where it is done with a femtosecond laser). The difference between these two methods lies in the fact that, in the first, the correction occurs on the surface of the cornea, while in the second in its interior. In PRK there is some minor discomfort the first 2-3 days, while in LASIK the discomfort is insignificant and eyesight restoration happens almost immediately, on the very first day. The final result is the same in both cases. An important role in the patient's decision to do away with glasses and contact lenses plays the trust and relationship between doctor and patient. The most important part of a refractive surgery is thorough preoperative tests, which will show us if the patient is eligible for a procedure in that particular area. Detailed and thorough preoperative tests ensure the success of the procedure. Timewise, the procedure lasts only a few minutes and it is never longer than 5 or 6 minutes for both eyes. The doctor uses local anesthesia and the patient feels no pain. It is important to note that the correction is permanent and in the very few cases where some degrees of the condition remain, then an additional laser procedure can be done to achieve full correction. An important role in the patient's decision to do away with glasses and contact lenses has the trust and relationship between doctor and patient. The 25 years of laser use allow us to say that the possibility of serious complications is negligible. Even those rare complications can be treated. We are in a position to say with absolute certainty that the chances of infection from contact lenses are more than the possible complications of refractive surgery.
Keratoconus is a non-inflammatory disorder of the cornea, which is characterized by the presence of a progressive deformation of its surface. The cornea gradually takes a “conical” shape (it expands by creating an extrusion), deforming the reflection formed in the fundus of the eye. A progressive thinning can also be observed, as well as scarring, and finally opacity in the area where the cone has formed. Despite ongoing research, the causes of keratoconus are essentially unknown. It is generally considered a genetic disease caused by multiple factors, mainly irregularities in the structure or the metabolism of various segments of the cornea. It used to be considered a rare disorder, perhaps because there weren't any diagnostic means to detect it in the early stages. Today we know that keratoconus is not so rare. There are more than 20,000 people in Greece with keratoconus (approximately 1 for every 2,000 people). It usually appears in adolescence and progresses relatively fast, while later the rhythm of deterioration decreases and stops at around 35 years of age. Physical examination does not always provide evidence for a positive diagnosis. However, keratometry can give altered parameters. The patient presents an irregular progressive astigmatism that previously did not exist. In more advanced stages, the diagnosis is easier and with the help of a slit lamp, the cornea can present the known conical form, as well as thinning and haze of its central area. Nonetheless, positive diagnosis occurs with the help of an electronic device and a test called “corneal map” (corneal topography). In this test, a 2D image of the corneal topography is taken and, based on that, we can diagnose even the subclinical forms (those that haven't presented any symptoms). It is strongly believed today that the riboflavin method can substantially delay or even stop the development of keratoconus, saving the patient from a potential corneal transplant. This method is still evolving and is called C3-R (Corneal Collagen Crosslinking with Riboflavin). Through lab tests and clinical examinations, it has been proven that it reinforces the inner structure of the cornea, stabilizing its architecture and, specifically, strengthening the bonds of the corneal collagen fibers, which are one of the basic ingredients for maintaining its structure.
C3-R treatment can be done at the clinic and lasts about 60 minutes. During the treatment, drops of a riboflavin (B2) mix are instilled, which are then activated with UV rays.
Cataract is a haze of the natural lens inside the eye. This lens, which is found behind the iris (the colored part of the eye) is capable of moving and changing shape, so that it can function exactly like the lens of a camera, by focusing bright images on the retina, which, in turn, sends them to your brain. The human lens, consisted mainly of protein and water, can present some haze, in such a degree that the light and images are not allowed to reach the retina. Eye damage, certain disorders or even some medicine can cause this haze. In more than 90% of the cases, however, this haze is cause by the aging process. Cataract isn't a deposition in the eye and cannot be removed with diet or laser. The best way to treat cataract is to remove the old, hazy lens and to replace it with an artificial one. Cataract can be the cause of the blurring of clear images, the dimming of bright colors or a decrease in vision at night. It is also possible that it is the reason why reading or bifocal glasses that used to help you read or perform simple tasks, cannot help you any longer. Unfortunately, it is not feasible to prevent cataract, but only to remove and replace it with an artificial lens which can restore your vision and significantly improve quality of life. The proper time to remove cataract is when the quality of your vision starts causing restrictions in your activities and your enjoyment of life.
Glaucoma is a group of ocular disorders that share as a symptom the destruction of the optic nerve. The optic nerve consists of nerve fibers and is responsible for the transfer of images from the eye to the brain. Glaucoma is a disorder that leads to loss of vision without warning. It is possible that there are no symptoms in the early stages of the disease and that patients with glaucoma don't know they have it. Loss of vision starts with peripheral or side vision. This loss might be compensated by the unconscious turn of the head towards the corresponding side, which results in the patient not realizing his condition until there is a significant loss of visual acuity.
For this reason, early diagnosis is important and can prevent major damage. All people above forty years of age and especially those with a family history of glaucoma should be examined once or twice a year.
Diabetic Retinopathy is a disorder at the small (capillary) vessels of the retina. Diabetic retinopathy concerns every diabetic patient either insulin dependent (Type 1) and of young age or non-insulin-dependent (Type 2) and the disease has appeared later in life. The diabetic patient should know that the most important thing he needs to do for his condition is to keep his blood sugar under control. Blood sugar not under control causes a more rapid progress of diabetic retinopathy. He should also control his hypertension, his hyperlipidemia (cholesterol and triglycerides), if such exists, and limit smoking and alcohol. Patients with diabetes should be examined by an ophthalmologist once every 6 months. It is important to know that today, with the improved methods of diagnosis and treatment, only a small percentage of patients develop retinopathy and face serious eyesight problems.
Age-related macular degeneration, is the most common cause of irreversible blindness in the western world. This disorder affects the central area of the fundus, which is also the most important. The consequence? A gradual deterioration of our central vision with no other symptoms. Several studies have calculated that 6% to 10% of people among the ages of 65 and 74 years old and 19% to 30% of people above 75 years old have this disorder. As we can see, it is related to the elderly and for this reason it is called age-related macular degeneration. Age-related macular degeneration is caused by many factors. These risk factors may include age, heredity, light-colored irises, smoking, cardiovascular diseases, as well as sunlight. The most important factor is, of course, the aging process.
What can we do to prevent it?
Wear sunglasses with UV filter, to protect our eyes.
You can take dietary supplements, multivitamins and zinc products. Even though it is difficult to prove those products' preventive action, several studies have shown that they can help delay the disease. Dosage should be indicated by the ophthalmologist in cooperation with the pathologist, in case of contraindications.
You should regularly check your eyes after 40 years of age and visit your ophthalmologist as soon as you observe changes in your eyesight, especially scotomas related to your central vision. Special diagnostic tests like OCT and Fluoroangiography are quite often valuable in the treatment of the disease.
You should reduce or, better yet, quit smoking.
Regulate your blood pressure, your cholesterol and consult with a cardiologist, in case it is needed.
Published in the magazine Dimosios Tomeas, volume 286, July-August 2011
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