Whether it’s Femto-LASIK or Trans-PRK, every medical procedure carries certain risks of complications and side effects.
Here you can find out what the most common after-effects of laser vision correction are, which procedures they typically occur with, what causes them and how you can best avoid or treat them.

Is laser eye surgery safe?

The overall complication rate for laser eye surgery is very low.
Most studies show that serious complications occur in less than 1% of patients.
Common side effects, which are often misunderstood as complications, include temporary symptoms such as dry eyes, halos and mild visual disturbances, which usually disappear on their own within a few weeks to months after the operation.

In the long term, most patients have a significantly improved quality of vision after laser eye surgery and do not require any further visual aids.
Studies show that the satisfaction rate among patients who have undergone laser eye surgery is over 90%.

Dry eyes as a complication after laser vision correction

Dry eyes are a common side effect after laser eye surgery and are characterized by symptoms such as burning, itching, a foreign body sensation and redness of the eyes.
Patients may also complain of blurred vision and general discomfort, especially with prolonged use of digital screens or in air-conditioned environments.

With which laser eye surgery can it occur?

• Femto-LASIK
• Trans-PRK
• SmartSight (ReLEx SMILE)

What is the reason for this?

• Impairment of the nervesDuring the procedure, small nerves in the cornea that are responsible for regulating tear production are severed.
  This can temporarily reduce tear production.
• Change in the quality of the tear filmThe procedure can affect the composition and distribution of the tear film, resulting in insufficient moisturization of the ocular surface.
• Healing processesDuring healing, there may be temporary disturbances in tear production as the tissue and nerves regenerate.

What should you do about it?

To alleviate and treat dry eyes after laser eye surgery, you can take the following measures:

• Artificial tearsRegular use of artificial tears can help to keep the eyes moist and relieve symptoms.
• Eye dropsEye drops prescribed by a doctor, which have an anti-inflammatory effect or stimulate tear production, can also be helpful.
• Omega-3 fatty acidsThe intake of omega-3 fatty acids, for example through dietary supplements or an appropriate diet, can improve the quality of the tear film.
• Environmental adjustmentsAvoiding dry, windy environments and using a humidifier can also help to reduce symptoms.

Over- or undercorrection

Overcorrection or undercorrection after laser vision correction is manifested by unsatisfactory visual results where the original vision defect has either not been fully corrected (undercorrection) or has been corrected too much (overcorrection).
Symptoms may include blurred vision, difficulty focusing, headaches and a general dissatisfaction with the quality of vision.

With which laser eye surgery can it occur?

These complications can occur with all types of laser eye surgery, including:

• Femto-LASIK
• Trans-PRK
• SmartSight (ReLEx SMILE)

What is the reason for this?

The causes of overcorrection or undercorrection can be manifold:

• Individual healing processesEach patient heals differently and the eye’s reaction to the laser can vary.
• Laser parametersInaccuracies in the setting of the laser parameters or the individual planning of the operation can lead to an inaccurate correction.
• Corneal thicknessThe nature and thickness of the cornea affect how the laser corrects the refractive error and can lead to unpredictable results.
• Age and visual defectThe age of the patient and the extent of the original visual defect can also play a role.

What should be done about it?

• Post-correctionAnother laser procedure can be performed to correct the remaining visual defect.
  This is often referred to as “enhancement”.
• Glasses or contact lensesTemporary or permanent glasses or contact lenses can be worn to improve the quality of vision.

Halos and glare after laser eye surgery

Halos appear as glowing rings around light sources, especially at night or in poorly lit environments.
Glare refers to an increased sensitivity to glare, where light sources appear particularly bright and distracting.
These symptoms can significantly impair night vision and make driving or other activities in low light difficult.

With which laser eye surgery can it occur?

• Femto-LASIK
• Trans-PRK
• SmartSight (ReLEx SMILE)

What is the reason for this?

There are many causes of halos and glare after laser eye surgery:

• Changes to the corneal surfaceThe laser changes the shape and structure of the cornea, which can lead to irregularities that scatter the light and cause these visual phenomena.
• Healing processDuring healing, the corneal layers may rearrange themselves, causing temporary irregularities.
• Pupil size: With large pupils, the light can reach the retina outside the treated area and cause halos.
• Night visionThe differences in refraction between the central and peripheral areas of the cornea can be particularly noticeable in low light conditions.

What should be done about it?

• Lifestyle adjustmentAvoid driving at night and in bright light until symptoms improve.
• Special glassesUse night vision goggles or glasses with anti-reflective lenses that can help reduce glare.
• Artificial tearsThese can help to keep the eye surface smooth and minimize light scattering.
• PatienceIn many cases, halos and glare improve within a few weeks to months as the eye adapts to the new corneal shape and healing progresses.
• Post-correctionIn severe cases, post-correction may be considered to further smooth the corneal surface and reduce symptoms.

Postoperative infection

Postoperative infections after laser eye surgery are rare but serious complications that can manifest themselves in severe pain, redness, increased lacrimation, pus discharge and a sudden deterioration in vision.
Patients may also experience increased sensitivity to light and general discomfort in the eye.

With which laser eye surgery can it occur?

• Femto-LASIK
• Trans-PRK
• SmartSight (ReLEx SMILE)

What is the reason for this?

The causes of post-operative infections are usually due to the penetration of bacteria, viruses or fungi into the operated eye.
This can happen during or after the operation, especially if postoperative hygiene measures are not strictly adhered to.
The most common reasons include

• Contaminated instruments or environmentLack of sterility during the operation.
• Inadequate postoperative careFailure of the patient to follow the instructions for post-operative care and hygiene.
• Pre-existing conditionsPre-existing eye infections or a weakened immune system can increase the risk.

What should be done about it?

• Immediate medical examinationIf an infection is suspected, an ophthalmologist should be consulted immediately.
• Antibiotic eye dropsThe doctor may prescribe antibiotic eye drops or systemic antibiotics to fight the infection.
• Strict hygiene measuresStrictly follow care and hygiene instructions, including regular cleaning of the eye and avoiding contact with contaminated surfaces.
• Regular check-upsRegular follow-up examinations are important to monitor the healing process and ensure that the infection has completely cleared up.

Prevention

• Sterile surgical techniquesEnsuring sterility during the operation by the medical staff.
• Postoperative care instructionsFollow the instructions given by the doctor for the care of the eye after the operation.
• Avoid contaminationAvoid touching the eyes with unwashed hands and protect the eyes from potential sources of infection.

Fluctuating visual acuity immediately after the procedure

Fluctuating visual acuity is a common phenomenon immediately after laser eye surgery.
Patients often report that their visual acuity can vary, especially in the first few days to weeks after surgery.
These fluctuations can manifest as changing clarity of vision, intermittent blurred vision and difficulty focusing.

With which laser eye surgery can it occur?

Fluctuating visual acuity is a completely normal side effect after laser eye surgery.
The eye first has to get used to the new visual impression and accordingly this “complication” can occur with any form of laser eye surgery and any type of lens surgery.

What is the reason for this?

• Healing processWhile the eye is healing, there may be temporary irregularities in the cornea that affect the refraction of light.
• Tear film stabilityAfter surgery, the tear film may be temporarily unstable, resulting in variable visual clarity.
• Swelling and reactionsSwelling and inflammatory reactions in the eye after surgery can also contribute to fluctuating visual acuity.
• Nerve regenerationThe nerves in the cornea regenerate, which can lead to temporary changes in visual acuity.

What should be done about it?

• PatienceFluctuating visual acuity is often a normal part of the healing process and usually improves within a few weeks.
• Artificial tearsThe use of artificial tears can help to improve the stability of the tear film and minimize temporary fluctuations in vision.
• Avoid overexertionAvoid activities that could strain your eyes, such as long hours in front of screens or intensive close-up work.
• Protection from environmental irritantsProtect your eyes from wind, dust and other irritants that could impair healing.

Epithelial ingrowths after Femto-LASIK

Epithelial ingrowths after Femto-LASIK are manifested by symptoms such as blurred vision, discomfort, a foreign body sensation and sometimes pain in the eye.
These ingrowths can lead to blurred vision and impaired quality of vision.

Epithelial ingrowth can occur especially with Femto-LASIK.
This is due to the fact that a corneal flap is created during this procedure, under which epithelial cells can grow in.

What is the reason for this?

• Mechanical dislocation of the flapDuring or after surgery, the corneal flap may not attach properly or may dislocate, allowing epithelial cells to migrate under the flap.
• Injury to the epitheliumDuring the operation, small injuries to the corneal epithelium may occur, which promote the ingrowth of cells.
• Insufficient cleaning of the flap areaIf the area under the flap is not completely clean, epithelial cells can remain and grow in.

What should be done about it?

• Regular follow-up examinationsClose follow-up examinations are crucial for the early detection and treatment of epithelial ingrowths.
• Monitoring and observationIn the case of small ingrowths, the ophthalmologist may decide to observe them, as in some cases they can stabilize on their own.
• Surgical interventionIf there are significant ingrowths or if the quality of vision is severely impaired, a new operation may be necessary.
  The flap is lifted, the ingrown cells removed and the area thoroughly cleaned before the flap is repositioned.
• Eye drops and medicationIn some cases, special eye drops can be prescribed to support healing and minimize the risk of further ingrowths.

Corneal ectasia

Corneal ectasia after laser eye surgery is a rare but serious complication characterized by progressive thinning and bulging of the cornea.
Patients often notice a deterioration in visual acuity, distorted vision and possibly double vision.
These symptoms can gradually worsen and significantly impair the quality of vision.

With which laser eye surgery can it occur?

Corneal ectasia can occur after various laser eye procedures, but is more common with LASIK and Femto-LASIK.
It is less common with procedures such as PRK or Trans-PRK as these methods do not create corneal flaps.

What is the reason for this?

The causes of corneal ectasia are usually due to structural weaknesses in the cornea, which can be exacerbated by the laser eye surgery:

• Pre-existing corneal diseasesPatients with a thin or weak cornea before surgery have a higher risk.
• Excessive tissue ablationExcessive ablation of corneal tissue during surgery can compromise the structural integrity of the cornea.
• Biomechanical weakeningThe creation of a corneal flap during LASIK can reduce the biomechanical stability of the cornea, which can lead to a protrusion.

What should be done about it?

• Early detection and monitoringRegular follow-up examinations are crucial to detect early signs of corneal ectasia and to monitor its progression.
• Keratoconus contact lensesSpecial contact lenses can help to improve the quality of vision by compensating for the irregular corneal surface.
• Corneal crosslinking (CXL)A minimally invasive procedure that strengthens the cornea and increases its biomechanical stability.
  The cornea is soaked with riboflavin and then irradiated with UV light to create new cross-links between the collagen fibers.

Corneal transplantationIn severe cases, a corneal transplant may be necessary to restore the quality of vision.