For most people, the effects of refractive surgery are mild and tolerable. LASIK is a corneal treatment and can only treat corneal astigmatism. It is well known that LASIK alters the tear film and can cause dry eyes, which is a common cause of dissatisfaction for patients. A recent study found that 20% of eyes that underwent LASIK experienced chronic dryness that lasted for six months or more.
None of the eyes had symptoms of dry eyes before surgery, and the average age of the patients was 31 years. Evaluations included subjective complaints of dry eye, tear break time, corneal staining, corneal sensitivity test, and Schirmer I test. The results showed that risk factors for chronic dry eyes included greater attempts at refractive correction, greater depth of ablation, and female gender. It is important to evaluate for dry eye before the operation, as some patients may have dry eyes before surgery.
Signs of dry eye include contact lens intolerance, tired eyes, and fluctuating vision when reading. Patients should understand that LASIK will not improve dry eyes and can even make things worse temporarily. Generally, the tear film returns to normal four to six months after LASIK and symptoms improve. Treatment may be needed in the meantime; Restasis (0.05% cyclosporine eye emulsion) is often used to treat these patients.
However, Restasis does not always cure the problem and other modalities such as punctal occlusion or a nutritional product may be necessary. Adaptation occurs over time, so patients adapt to the way they see after LASIK. This is especially true with higher correction levels as the quality of vision and the way it is processed are very different than with thick eyeglasses or contact lenses. Adaptation usually takes between a few weeks and two to three months. Patients with residual astigmatism greater than 0.75 D tend to have more visual problems; research has shown that those with astigmatism of 0.75 D or more tend to have decreased mesopic vision. Additional surgical treatment may be necessary if the patient has an irregular flap in the topography or if wavefront analysis reveals a major aberration that needs to be treated.
Dr. Stonecipher points out that patients rarely have inappropriate expectations; it is usually just a matter of finding a dry eye treatment regimen that works for them. People who suffer from astigmatism should be very careful when considering LASIK surgery as it involves manipulating and restructuring the cornea and can sometimes worsen astigmatism. It is unusual to see an increase in corneal astigmatism after laser vision correction but like nearsighted patients, those with significant astigmatism before surgery may develop astigmatism after surgery. LASIK can help with corneal astigmatism within a certain range of refractive error. Surgeons believe they are counseling patients to ensure appropriate expectations but it is difficult for patients to express their expectations accurately.
If a patient said that the result had to be perfect or they wouldn't be happy, surgeons would not operate on them as it is impossible to advise before the operation. In conclusion, LASIK can help with corneal astigmatism within a certain range of refractive error but people who suffer from astigmatism should be very careful when considering this type of surgery as it can sometimes worsen astigmatism.
