مهندسی پزشکی

Dry eyes

95% of patients report dry eye symptoms after LASIK^[25] Although it is usually temporary it can develop into chronic and severe dry eye syndrome. Quality of life can be severely affected by dry eye syndrome.^[26]

Underlying conditions with dry eye such as Sjögren"s syndrome are considered contraindications to Lasik.^[27]

Treatments include artificial tears, prescription tears and punctal occlusion. Punctal occlusion is accomplished by placing a collagen or silicone plug in the tear duct, which normally drains fluid from the eye. Some patients complain of ongoing dry eye symptoms despite such treatments and dry eye symptoms may be permanent.^[28]

Halos

Some post-LASIK patients see halos and starbursts around bright lights at night. At night, the pupil may dilate to be larger than the flap leading to the edge of the flap or stromal changes causing visual distortion of light that does not occur during the day when the pupil is smaller. The eyes can be examined for large pupils pre-operatively and the risk of this symptom assessed.

Complications due to LASIK have been classified as those that occur due to preoperative, intraoperative, early postoperative, or late postoperative sources:^[29] According to the UK National Health Service complications occur in fewer than 5% of cases.^[25]

Other complications

• Flap complications – The incidence of flap complications is about 0.244%.^[30] Flap complications (such as displaced flaps or folds in the flaps that necessitate repositioning, diffuse lamellar keratitis, and epithelial ingrowth) are common in lamellar corneal surgeries^[31] but rarely lead to permanent loss of visual acuity. The incidence of these microkeratome-related complications decreases with increased physician experience.^[32]
• Slipped flap – is a corneal flap that detaches from the rest of the cornea. The chances of this are greatest immediately after surgery, so patients typically are advised to go home and sleep to let the flap adhere and heal. Patients are usually given sleep goggles or eye shields to wear for several nights to prevent them from dislodging the flap in their sleep. A short operation time may decrease the chance of this complication, as there is less time for the flap to dry.^{[citation needed]}
• Flap interface particles – are a finding whose clinical significance is undetermined.^[33] Particles of various sizes and reflectivity are clinically visible in about 38.7% of eyes examined via slit lamp biomicroscopy and in 100% of eyes examined by confocal microscopy.^[33]