Surgery for Presbyopia
What is presbyopia or tired eyes?
Presbyopia makes it difficult to see things close up and usually starts between 40 and 45 years of age and affects 100% of patients over 50. Generally, that means patients who are in an active phase of their lives, from the point of view of one’s intellectual and professional life, and for whom depending on glasses or contact lenses may sometimes be uncomfortable.
What causes presbyopia?
The crystalline is a flexible lens inside the eye, behind the pupil. Its elasticity allows it to change shape to focus on objects at different distances. With time the lens hardens and so loses elasticity, with the result thatthe focus point gradually gets further away. It must be pointed out that this is a physiological process and affects all patients at the ages mentioned and is just the first step in the transparent crystalline becoming opaque with cataracts later in life. It is therefore important to bear in mind that there are no exercises or drugs that can prevent the onset of presbyopia.
What are the symptoms of presbyopia?
Symptoms typically consist of difficulty in seeing small objects close up, the need to hold these objects away from us to be able to focus on them better, or to find better light. In general, the symptoms start earlier in patients who are far-sighted, then in those who are emmetropic, i.e. those who do not need glasses for distance, and finally in those who are myopic, or near-sighted.
Can presbyopia be operated on?
Until recently refractive surgery (a procedure aiming to eliminate or reduce the need for glasses) produced excellent results in the correction of short-sightedness, far-sightedness and astigmatism, particularly in the last 15 years with the use of the Excimer laser and derived techniques, although it did not correct presbyopia satisfactorily. The procedure gave ‘incomplete’ or temporary solutions for many patients of 45-50 years of age wanting to leave their glasses behind. Spectacular advances in the design of intraocular lenses have led to the development of the multifocal intraocular lens, so we can now say that yes, there is a solution for presbyopia, with highly satisfactory results for the patient.
How does the surgical correction of presbyopia work?
Presbyopia, as we have explained, is caused by the loss of elasticity in the crystalline. Therefore, it seems to make sense to seek the solution in replacing the hardened crystalline with a multifocal intraocular lens, with which not only presbyopia is corrected, but also certain degrees of near-sightedness or far-sightedness the patient may have had previously. So the patient’s sight is satisfactory without glasses for longer distances and good enough for shorter distances for everyday life (to read the newspaper, to read the prices on articles when shopping, etc.), reducing the need for glasses with very small items or in bad light.
Which patients are candidates for multifocal surgery?
- Patients who are going to be operated on for cataracts and can take advantage of the surgical procedure to correct their presbyopia at the same time.
- Patients who do not have cataracts, but who would like to stop using reading glasses, irrespective of whether they are short-sighted or far- sighted. This is what is known as PRELEX surgery, which is presbyopia corrective surgery.
- Young patients under the age of 40 with congenital cataracts or unilateral cataracts, as caused by an accident, for instance.
Clearly, the final decision will be determined taking into careful account the personal characteristics of each individual patient during an examination prior to surgery – age, prior refractive conditions, profession and so on.
What is the operation like?
It is basically very similar to cataract surgery and takes about 10 to 15 minutes. Just before the procedure, drops are applied to dilate the pupil, after which a few anesthetic drops, the only anesthetic needed, are applied. In the case the patient is very nervous, a mild sedative will be given. Through an incision of less than 3 millimeters, a cold ultrasound probe is inserted to dissolve and aspirate the hardened crystalline. When the space holding the crystalline is completely clean, the new artificial crystalline or multifocal intraocular lens is inserted, whose flexibility allows it to be injected through the same tiny incision made to remove the natural crystalline. The incision does not require suture in the vast majority of cases.
What care does the patient need in the days following surgery?
After the operation, antibiotic eye-drops are prescribed to prevent infection - a treatment patients must follow to the letter. Furthermore, the eye must not be pressed or rubbed and the patient must avoid strenuous activity or lifting heavy weights. On the other hand, there is absolutely no reason patients cannot watch television, read as much as they wish, use a computer, walk (not run) or use normal means of transport.
What complications can there be?
Serious complications are extremely rare and are the same as those that may come up with traditional cataract surgery, such as post-operative infection, intraoperative bleeding or the crystalline deposits in the vitreous humor, and have an incidence rate of less than 0.1%.
Minor complications include capsular opacification or hazing, i.e. the capsule into which the intraocular lens is implanted. These cases are easily solved using a laser known as a Yag laser, which allows opacity to be removed in just 5 minutes during the consultation, with the patient recovering sharp vision within 24 hours. In some infrequent cases, there may be what is known as ‘refractive error’. Although the equipment used to calculate the strength of the intraocular lens is very accurate and the formulas used as a basis are highly reliable, it may be the case, on highly unusual occasions, that the diopters prescribed are not completely corrected, something applicable to all refractive surgery. In most cases, these will be minor defects, in which case glasses will be prescribed. In the extremely rare case that the defect is noticeable, it may be necessary to operate again to remove the lens and replace it with the right lens.
What side effects might the patient with multifocal intraocular lenses notice?
On occasion, the patient might see halos around lights at night, which generally diminishes or disappears gradually. In certain cases, the patient may need low prescription glasses for reading fine print.
At what age can I be operated?
The minimum age is around 45-50, although everything depends on the patient’s refractive condition, because, as we have seen, symptoms of presbyopia appear sooner in farsighted people and later in the nearsighted. In as far as the maximum age is concerned, there is practically no limit, even patients with cataracts can benefit from this type of surgery.
Is there any profession that is not suitable for this surgery?
Due to the appearance of halos mentioned above, the effect may be troublesome for those professionals driving at night for hours on a regular basis, such as bus and truck drivers, pilots and so on.