Special Hospital SVETI VID has introduced REFRACTIVE SURGERY, in this area, surgical and laser procedures for the correction of refractive errors such as myopia, hyperopia and astigmatism. This subspecialised field of ophthalmology has existed in the contemporary ophthalmology since 1980s, and has finally become available in this area owing to the SVETI VID eye hospital.
WHAT IS THE REFRACTIVE SURGERY?
Refractive surgery refers to a series of procedures – surgical and laser – used for correcting the refractive errors – far-sightedness, near-sightedness and astigmatism. It eliminates the dependence on the conventional accessories such as contact lenses and spectacles. Refractive surgery in children is appropriate in special indications, in the period of very intensive development of visual acuity, when full correction is mandatory but not achieved, due to contact lenses and spectacles intolerances or incompliance, with severe anisometropia or bilateral high refractive errors resistant to the conventional therapy. These methods officially present in the world’s ophthalmology for many years, finally became our reality as well, with the foundation of Special Hospital SVETI VID.
The potential of refractive surgery is enormous, for both small and large refractive errors including astigmatism as well, by selecting the most adequate method. Enormous experience in this field is of great importance for a good response. It is especially important to consider an appropriate selection of methods for each patient, methods-combination, or if necessary, custom approach.
The excimer laser is certainly the most popular and the least invasive method. It represents a computer guided and well controlled appliance of a laser beam – actually high frequency ‘flying’ laser spots, used to reshape the corneal surface according to a desired one and therefore change its refractive power into desired one. The dioptric range planned to be “taken” off by a laser is defined in advance by specific parameters established during the examination. Very important is the corneal thickness, its shape and stability prior to the laser procedure. It is used for the correction of myopia up to – 13 D (with astigmatism) and up to +6 D of hyperopia, when the thickness is adequate. In thin corneas, the dioptric range to correct is bellow the range mentioned above. When a refractive error is not stable, the laser procedure could be done for achieving comfortable, sharp vision and getting rid of spectacles. If necessary, later small changing could be corrected again, depending on the thickness of the cornea (enhancement).This is an essential condition for the safety of the procedure. For a higher range of diopters, and thin cornea, the suggestion is surgical treatment with the implantation of special intraocular lenses regarding the following possibilities:
a) Swith refractive intraocular lens implants, without the removal of the natural, crystalline, biological lens, with the accommodative power saved. This is the so-called PHAKIC INTRAOCULAR LENS (IOL) for high myopia and high hyperopia and PHAKIC TORIC IOL for spherical and astigmatic correction combined. The method is applied in patients that still have the accommodation, up to 35-40 years of age. Thus, the accommodation is preserved, and far vision corrected. The quality of these lenses is exceptional. In this way it is possible to correct myopia up to – 22D (or -25 D, depending on the type of lens) and hyperopia up to +10 /, with toric correction up to 7 D (phakic toric). There are different types available – angle support and iris-claw lenses, flexible for small incision implantation. The results are brilliant. The surgery is short, in local anesthesia mostly, with fast recovery, even the day after. A binocular operation is possible, or two operations peformed day after day. Phakic IOLs are used in pediatric refractive surgery, for the correction of high binocular refractive errors or in very high anisometropia, when the conventional therapy is without response and severe amblyopia is threatening. In this case, general anesthesia is mandatory.
b) In older myopic or hyperopic patients, when the natural human lens has lost its accommodative power and therefore another spectacle dependence is needed, well known as “reading glasses”, the method of choice would not be laser, or phakic iol implantation, but LENS EXCHANGE surgery with the type of the lens implant especially selected to fit the patient’s needs, and professional or other requirements. A large number of patients are extremely happy with the selection of the multifocal foldable intraocular lens with a comfort of near vision for close objects (imitation of accommodation), intermediate distances (computer) and far distances vision. The patients having cataract surgery (phacoemulsification) could correct their pre-existing refractive problems, choosing multifocal implants. Thus a multifocal foldable lens practically removes the double dependence on spectacles, giving the opportunity of having a good quality of vision at different distances (imitation of accommodation). All procedures require appropriate surgical skills and performance, since surgical precision is a very IMPORTANT premise, in order to use the best potential of refractive surgery. Therefore, it is very important that the surgeon who performs refractive surgery is an expert in this field, and offers the maximum to his patients. In congenital or traumatic cataract removal in children older than 5 years of age, with moderate or little amblyopia, a multifocal implant is suggested to compensate the loss of accommodation after cataract surgery, and nearly “re-establish accommodation“.
Lens exchange surgery is done on both eyes simultaneously, or day by day, in local (in children under general) anesthesia, in one day surgery. Recovery – the very next day, or a few days adaptation is needed. Refractive surgery is a crown of the surgical skill and the queen of ophthalmology. It is not yet present at our University. The beginners and those with no experience in these surgical approaches do not hold a license to work in this surgical field as it could be dangerous. A lack of knowledge and experience in the field of refractive procedures might lead to misunderstanding and might be the source of deceptions and fear related to this way of the correction of diopter. But in fact, these procedures are official, very good if done by an expert in this field, giving satisfactions to those who have had it.
HOW CURRENT IS THIS PROBLEM IN THE CONTEMPORARY OPHTHALMOLOGY, HOW LONG HAS IT EXISTED AND WHAT RESULTS HAS IT ACHIEVED?
The very beginnings of refractive surgery date far back, more than half a century ago, from the pioneering steps by Baraquer, Sateau, Fiodorov, in their attempts to correct a diopter surgically. These first steps, though far from the final goal, certainly were very important for the further development of contemporary refractive surgery. From around two and a half decades ago to nowadays, refractive surgery has developed into a new subspecialty field of ophthalmology. Many congresses have been organized, and many journals and books have been written on this topic. For many years students and young ophthalmologists have been listening to lectures from this field of ophthalmology in the normal developed countries, but not here in Serbia, unfortunately. The use of Excimer laser in ophthalmology began in 1980s. These were the first, now abandoned, hardware lasers, which were the predecessors of the modern ones.
Today Excimer laser is of a software type, with the advantages of adjusting the procedures to each individual eye. It has reached its developmental culmination. A long time ago assigned aim has finally been achieved. A dream of millions of people has become a reality! Precision, predictability, safety and the satisfaction of the millions of patients who underwent the operation worldwide have influenced the highest authorities of ophthalmology to make the laser procedures official.
WHAT IS THE GOAL OF THE REFRACTIVE PROCEDURE?
The goal of refractive surgery is to provide a comfortable, functional visual acuity without contact lenses or spectacles, and to quit the dependence on the conventional helping devices. In children in special indications and with special needs, refractive surgery gives the best full correction of refractive errors, isometropic conditions, for better development of visual function and binocular vision, as the best way of reducing amblyopia.
WHAT MAKES PEOPLE ASK FOR SUCH CORRECTION OF DIOPTRY?
Mainly it is discomfort caused by the use of conventional devices, especially present in certain professions, or in normal everyday life. Young people usually have negative feelings about spectacles or simply cannot bear contact lenses and feel uncomfortable with them. Rarely, this might be a source of greater problems in communications and a reason for closing inside. Therefore their motivation to find a solution in refractive surgery is great. Another reason for choosing refractive surgery is the impossibility to correct the refractive error with spectacles, because of the type of error or big refractive differences between both eyes (anisometropia), even if patients have nothing personally against glasses, or simply cannot tolerate contact lenses. The financial aspect is of great importance. Refractive surgery is done once for life, while contact lenses are a lifelong dependence.
WHO ARE CANDIDATES FOR EXCIMER LASER?
The age over 18 or stability of refraction in the last two years is usually asked for, but this is not obligatory. The refraction may change physiologically even after the age of 18, which cannot be predicted. The same could happen even with spectacles or contact lenses, independently of laser correction. Laser can only correct the existing refraction, and it cannot stop further changing, if progression trends exist. High refractive errors are known to be unstable. If necessary, laser correction could be done additionally, as enhancement. Laser refractive surgery indicated in early childhood, up to 8 years of age, before the development of functional vision is finished, in special indications:
High refractive error in both or one eye (high difference between the eyes), and in children with special needs, when there are intolerance or incompliance with contact lenses and glasses, or lack of good response to them, and threatening amblyopia, consequently. There are no conditions for normal, binocular visual development without refractive surgery. Waiting until the age of 18 for laser correction would not make any sense in these cases, since the visual development is finished and amblyopia is resistant at that age. Laser cannot construct the vision. In older children, laser is also indicated in situations with “pretty normal” refractive errors, and good standard correction, when the child is professionally devoted to some sports and wants to get rid of standard correction.
WHAT DOES THE LASER PROCEDURE LOOK LIKE, HOW LONG DOES IT TAKE, WHICH ANESTHETIC IS USED?
The task of the computer-controlled application of a ‘cold’ laser beam is to change the refractive power of the cornea into desired one by remodelling the cornea. This can be achieved by a direct effect of the laser beam on the surface of the cornea (PRK method) for only a few seconds, with creating “an erosion zone” on the cornea. During the epithelization of this eroded area, the patient wears a therapeutic contact lens in order to protect the cornea and reduce the discomfort caused by the targeted ‘erosion’. This discomfort, which is usually expected the day after the intervention, is a common reaction and is overcome successfully with given eye drops and pills. Immediately after the intervention, the patients notice a dramatic improvement of vision, in spite of temporary blurred vision that lasts for a few days.
Another modality is LASIK, (laser assisted in-situ keratomileusis), a combination of the microsurgical and laser procedures. Lifting the epithelial flap is achieved using a microkeratom (a special instrument), followed by the laser treatment in deeper stromal layers. The epithelial flap is returned back to its position at the end. This method is more invasive. The healing period of the cornea lasts longer than for the PRK, although the discomfort is here reduced to only a few hours following the intervention. In both cases, the anesthesia is topical, with drops, and the patient returns home immediately after the intervention, and can go back to work in 5-6 days. The other modalities of the basic principles are Lasek and Epi lasik (variants between the PRK and Lasik).
WHO PERFORMS THE LASER PROCEDURES IN SVETI VID?
All refractive procedures are performed by Prof. Pavel Rozsival, a renowned member of the biggest European and the worlds’ ophthalmologic associations, who has been voted by the leading authorities as one of the most meritorious and outstanding people of the ophthalmology of the 20th century. Owing to him, with the adequately equipped hospital and education of personnel, we have managed to introduce refractive surgery in Serbia and make it available to all people, to patients and doctors. The surgery performed here represents the highest level of ophthalmic surgery.
HOW TO OVERCOME THE HIGH DIOPTRY PROBLEM?
Almost one third of the patients with a refractive error have high diopter. These “unhappy” people can hardly ‘fix’ their high diopter into the frames of glasses or correct it with contact lenses. With a higher degree of astigmatism, it is almost certain that with the conventional adjuvant an incomplete visual acuity, unreal picture and limited visual field would be a part of their everyday life. Without these ‘adjuvants’, in a significant number of patients visual acuity is limited to only around a few tens of centimeters. This shows extreme dependence on spectacles or contact lenses with other side effects of such adjuvants.
Excimer laser is suggested for the low and moderate myopia (near-sightedness) correction up to – 10.0 (approximately), for moderate astigmatism, and lower degree of hyperopia (far-sightedness) (up to around 2 D). It is not used for the correction of very high diopter. A dioptric range for “taking off” is strictly defined by specific parameters taken from the examination, which makes the laser procedure safe. Each refractive procedure, whether laser or surgical, has its particular requirements. An exceptional knowledge and experience in refractive surgery is mandatory for giving the best and safest solution to each patient individually. If these principles are followed, the results of the refractive procedures are excellent and they make many people happy.
Excimer laser is not recommended if the patient has a constitutionally “thinner” cornea, even for a moderate refractive error. Implant surgery is the method of choice in this case. This means the surgical implantation of a special intraocular lens that covers the dioptric range of up to – 20 D (near-sightedness) and up to +10 (far-sightedness). The patient’s own lens remains intact and stays at the same place behind the iris. Thus the accommodation (near vision) is not changed, while the correction for distant vision is achieved.
Therefore, the phakic IOL implantation is suggested to the age group of 21 to 40-45 years, while the accommodation still exists. For elder, whose biological lens does not accommodate any more, in the correction of high diopter, lens exchange surgery is recommended. In this case, various types of implants are available, depending on the problem the patient has. A special possibility for releasing double dependence on spectacles, for near and far at the same time, is the implantation of a multifocal intraocular lens. This gives the patient at that age the quality of vision close to the one he had with accommodation (imitation of accommodation). The intraocular lenses for high myopia and high hyperopia correction have been used for quite a long time. Today, we have also a phakic toric intraocular implant which gives chance to correct both, high spherical and astigmatic errors (up to around 7 D cylinder).
These are lenses of a refined design and material, completely adapted to the eye, and not very much alike their historical ancestors. Phakic intraocular lenses are well tolerated, with quick patient’s adaptation and excellent post-operative response. Many years of successful use in our practice have shown that the wished aimed visual acuity has been surpassed. The uncorrected achieved visual acuity is better than the best corrected preoperative visual acuity for about 1-2 lines more. This corresponds to the results worldwide. The important premise without which it does not make sense to think about qualitative refractive surgery is the skill and the refinement of the surgical technique, the surgeon’s experience in performing this prestigious surgery, and certainly the appropriate patient selection according to the official approved views. For a special group of people in presbiopic age (no accommodation any more) with combined spherical and high astigmatic refractive error, with or without cataract, there are possibilities for complete combined refractive error correction through lens exchange surgery and the implantation of a posterior chamber toric intraocular lens. PC toric is specially designed according to the specific parameters of each individual eye!!!
All this means that SVETI VID has focused on the world’s ophthalmology achievements.