LASIK
Laser in-situ keratomileusis (LASIK) is a type of refractive surgery which uses a laser to correct shortsightedness (Myopia) or longsightedness (Hyperopia) with or without Astigmatism. LASIK reshapes the corneal surface allowing light to be focused on the retina, thus improving vision.
Refractive surgeries are procedures altering the power of the eye to allow for desired spectacle independence with optimal vision, depth perception, and range of vision as well as improvement in quality of life and working ability. Eventually, being spectacle or contact lens-free means saving both time and money.
Eligibility for LASIK
Candidates for LASIK must meet the prerequisites to undergo such procedures. Patient selection is key for optimal outcomes.
Requirements:
- Age: 18 years or older (once the vision is stable).
- Vision: Stable refraction (glasses prescription) over past 6-12 months.
- Corneas must be adequately thick and healthy, determined by a pre-operative SCAN.
- General eye health must be good.
- Realistic expectations about the procedure.
Exclusion criteria:
- Unstable refractive error (need to change spectacles / contact lens regularly).
- Extreme levels of myopia, hyperopia, or astigmatism.
- Severe dry eye.
- Thin cornea, Cornea scars and Keratoconus (a disease with cone-shaped cornea).
- Advanced or Uncontrolled Glaucoma.
- Cataract.
- History of certain eye diseases (Viral infections like Herpes; Uveitis).
- Uncontrolled Diabetes and other medical conditions.
- During pregnancy and lactation (visual disturbances are common).
Expectations with LASIK
A thorough discussion about the patient’s vision needs, based on lifestyle and profession, is primordial with regards to expected outcomes. According to the 2016 Modern LASIK Outcomes study, 99.5% who had LASIK end up with vision between 6/6 and 6/12 without glasses or contact lenses, i.e., LASIK allows people to do most of daily tasks without corrective lenses.
However, the procedure does not halt natural aging of the eye:
- Presbyopia is normal, age-related diminution in near vision (> 40 years old) and, therefore, wearing glasses for certain activities like reading will be required.
- Natural ageing of the crystalline lens (cataract) changes distant vision.
Pre-operative Work-up and Comprehensive Eye Examination:
- Vision and refractive errors are measured.
- Overall health of your eyes is assessed by a detailed ophthalmic examination, including slit-lamp, and dilated retinal fundus examination.
- Mapping the surface of your cornea is done with the aid of scans (Corneal Topography and Pachymetry – patient-specific parameters such as corneal thickness and curvatures are required to program the computer-based laser for the surgery)
- Quality and quantity of tears secretion are assessed for dry eye status.
LASIK Surgery Procedure
LASIK is a common elective operative procedure performed worldwide. It has evolved into a 10-minute process that can correct most forms of refractive errors with optimal outcomes. It is performed under topical anesthesia, i.e., anesthetic eyedrops are instilled to numb the eye.
Intra-operative:
- An eyelid holder is placed on the operating eye to keep the eye open.
- A paper-thin flap in the cornea is created with the use of micro-blades or laser, lifted, and folded back.
- A beam of laser reshapes the cornea. Pre-operatively, the laser machine has been programmed with the personalized parameters of the patient.
- The flap is folded back down. It attaches on its own and will heal in place.
Post-operative:
- Eyedrops are prescribed (Anti-biotics, Anti-inflammatory, Eye lubricants).
- Wearing of a shield while sleeping for a few days to protect the eye while it heals.
- Same-day discharge.
- Regular follow-up as per the Ophthalmologist / Corneal Specialist.
What are the risks of LASIK?
LASIK carries risks of complications like any other surgery. Most are temporary but, in rare cases, some symptoms may last longer or remain.
Temporary side-effects may include:
- Hazy or blurry vision.
- Difficulty with night vision and/or driving at night.
- Itchiness and dryness.
- Glare, halos or starbursts around lights and light sensitivity.
- Discomfort or pain.
- Small pink or red patches on the white of the eye.
Vision-threatening complications include:
- Post-operative infections are very rare (reported incidence of <0.5%). Mild infection resolves with antibiotics while severe may cause permanent corneal scars or vision loss.
- Ectasia (occurrence of corneal thinning or steepening) may require further treatment like Collagen Cross Linking and use of rigid contact lenses.
- LASIK flap-related issues leading to corneal surface irregularity are rare (<1%).
- Worse vision than before LASIK, even with glasses or contacts (very rare).
Non-vision-threatening complications include:
- Residual refractive errors are improved with glasses, contact lenses, or additional laser surgery. Refractive surgeries do not guarantee complete spectacle independence.
- Regression of vision, especially in patients with high refractive error.
- Persistent glare and halos.
- Dry Eye. It is a common side effect with mild course in most cases, peaks at 3 months and usually resolves by 6 months and can be managed with eye lubricants.
LASIK Enhancement:
Retreatment can be considered in such cases:
- Residual refractive error.
- LASIK flap-related folds.
- Regression in vision.
Alternatives to LASIK or LASIK Enhancement:
Lens-based procedures like Phakic Intra-ocular Implants (ICL – Implantable Collamer Lenses) or Refractive Lens Exchange (RLE) can be beneficial in selected cases.
Advances in Refractive Surgery
Advances in surface ablation techniques have given rise to possibilities for presbyopic (age-related progressive change in near vision) treatment options.
Refractive corneal lenticule extraction (RCLE or ReLEx) is a relatively new technique, dependent on femtosecond laser (FS-LASIK) and without the need for corneal flap creation. Modalities like FLEx (Femtosecond Lenticule Extraction) and SMILE (Small Incision Lenticule Extraction) are being established.
ICL implantation is on the trend as a primary procedure due to various advantages over laser-based procedures. An artificial intra-ocular lens is implanted inside the eye to correct high degrees of refractive error or when corneal refractive surgery is contraindicated. Advantages include quicker recovery and reversibility.
Dr Reshvin Matoo
Consultant Ophthalmologist
Dr Agarwals Eye Hospital, Ebene, Mauritius.
June 2023
Author’s Profile:
Consultant Ophthalmologist and Cataract Surgeon for Dr Agarwals Eye Hospital since 2019. Holds consultations at Ebene, Flacq and Goodlands branches.
Dr Agarwals Eye Hospital, with over +110 branches across India and Africa, offers comprehensive eye examination with state-of-the-art technologies for scans and surger
