Absolute and relative obstacles to performing laser vision correction

Among the contraindications to laser vision correction surgery, there are absolute and relative contraindications.

The first exaggerate the fact that our eyes cannot undergo laser intervention. So it makes no sense to look for a surgeon by force who, ignoring the results of our research, would break procedures and perform the operation after all. However, whenever we leave a doctor’s office with a refusal to perform a laser procedure, we need to be sure that the refusal is not due to the “me” of the specialist. It’s possible that he’s refusing because his clinic doesn’t have the right equipment, or he himself doesn’t have the right skills. So we need to ask directly whether the refusal is related to our medical condition and the anatomical conditions of the eye, or to the technical capabilities of the clinic. In the latter case, we should seek help elsewhere.

The second is the contraindications, which are temporary. This means that when the objective obstacles to the procedure disappear, it can be performed. It is only necessary to create the right conditions for this, to wait for a good time. With the development of medical science and the emergence of new treatments, some absolute contraindications are moved to the list of relative contraindications. This means that each patient’s case is analyzed individually by at least two specialists – an ophthalmologist and the attending physician.

Absolute Obstacles:

• Certain corneal changes (corneal cone, congenital corneal pathologies, dystrophic diseases, corneal scars) and the thickness, elasticity and degree of corneal hydration. The ratio of corrected diopters to corneal thickness also determines whether correction is possible. All contraindications, let’s call them, periocular, are related to the fact that in the course of the above-mentioned corneal diseases, the cornea can become significantly thinner, and in an eye with a healthy cornea it can be naturally too thin. During an intervention, such as the FemtoLASIK technique, the surgeon uses up the cornea – that is, the convex outer layer of the eyeball in its front part – to create a so-called corneal flap. Different so-called optical zonules of the procedure, wear down the cornea differently. If the doctor, after examination, finds that our cornea is too thin, he will not be able to develop the so-called architecture of the procedure, i.e. plan the operation in such a way as to achieve the optimal result for the patient. Programming and carrying out the procedure, even with the most precise lasers, will simply not be possible.

• Too high a visual defect: nearsightedness above -10 diopters and farsightedness above +4 diopters. Laser is not sufficient for correction, but then a phakic lens can be permanently implanted [link] or a refractive lens replacement can be performed.

• Astigmatism, which is difficult to treat. 99% of astigmatism cases are laser-correctable defects. The problem arises when a complicated form of astigmatism co-occurs with another visual defect and/or eye disease.

• The tendency to form scarring, or thickened skin, which forms at the site of a former injury or other break in tissue continuity, such as a surgical cut, and grows in size beyond the limits of the original injury, plus hurts, itches, impedes movement and causes significant discomfort.

Relative Obstacles:

• Age too young. The fact that the doctor refuses laser vision correction to a person who is too young (most often before the age of 18, less often – 21) is related to the fact that as long as the eyeball is in the growth phase, each elongation of 1 millimeter induces a visual defect of -3.00 diopters. When we reach the appropriate age, the eyeball stops growing, it will be equivalent to the fact that another relative obstacle disappears, viz.
• Unstabilized visual defect. Performing laser vision correction on an unstabilized defect may involve correcting it in the future, i.e. another surgery.
• Too advanced age. In this case, in turn, the issue is The thickness, degree of hydration and elasticity of the cornea and the patient’s overall health. If the eye is, colloquially speaking, very worn out, its physical parameters may prejudge the possibility of laser intervention. Additional systemic diseases may be the dot over the i in the decision to pursue treatment other than laser.
• Autoimmune (autoimmune) diseases, such as Hashimoto’s disease, type 1 diabetes, rheumatoid arthritis (RA), as well as allergy and atopy. Increasingly, they are being moved from the list of absolute contraindications to relative contraindications. In each case, however, the ophthalmic surgeon must not only conduct a very precise qualifying examination, but also consult with the patient’s doctor in charge of the autoimmune disease. It may be possible to perform laser vision correction surgery while the disease is stabilized or in remission. It is worth being aware, however, that autoimmune diseases are diseases in the course of which patients register disorders and significant immune deficiencies, increased intrathecal inflammation, hormonal disorders, and consequently problems with wound healing. If doctors do not manage to create such a “wicket in time” that would give a chance for laser vision correction, we must look for another method of treatment.
• Pregnancy and breastfeeding. Once the baby is born and nursing is complete, the patient is ready for the procedure. Unless other contraindications come into play.

• Taking certain medications, such as steroids, which increase the likelihood of ocular complications such as glaucoma and post-steroidal cataracts. If steroids can be temporarily discontinued, an attempt can also be made to prepare the patient for the procedure. Also, the use of hormonal medications, including birth control pills, requires the development of a regimen for their use in the pre- and post-operative periods in cooperation with the attending physician.

Dry eye syndrome. Abnormal composition or too rapid evaporation of tear fluid leads to excessive drying of the cornea and conjunctiva. Patients often show pinpoint epithelial defects in the lower part of the cornea or within the eyelid stroma. The lesions occur bilaterally and are very chronic. There is no complete cure for dry eye syndrome. The symptoms of the disease usually persist throughout life. The exception is the so-called secondary dry eye syndrome, associated with the use of medications, the symptoms of which may regress or diminish after their withdrawal.