Indication
Gold standard for the correction of small to moderate refractive errors
transPRK/PRK only if:
- Schirmer test < 10 mm
- Thin cornea < 480 µm
- Irregular topography (inferior steepening > 1.5 D, posterior float > 14 µm, etc.)$
- Scars
- Combat sports, police
Anatomical prerequisites for PRK
- Myopia up to -6 D
- Hyperopia up to +3 D
- Astigmatism up to 5 D
- Age > 18 years
- Stable refraction (<0.5 D for 6-12 months)
- No pregnancy / breastfeeding
Contraindication
- Keratoconus (may be possible after crosslinking treatment)
- Cataract or glaucoma
- Inflammatory eye diseases
- Rheumatological diseases
- Therapy with isotretinoin (e.g. Roaccutane®)
- Combat sports, police
Preparation
- Topography/tomography (Pentacam)
- Patient counseling -> see LASIK informed consent form (femto-related vacuum sensation may be noticeable)
- No sick leave certificate
- Preoperative preparation
- Oxybuprocaine 0.4% SDU eye drops 3x every 5 minutes
Surgical materials
- Start up the femtosecond laser in the cornea program
- Program the patient
- Attach the first procedure pack
- Calibrate the excimer laser
- Hibidil solution
- Round swabs x6
- BSS solution
- Oxybuprocaine single-dose eye drops (unsterile, on the excimer laser above the binocular)
- Triangular swab
- Hockey knife (reusable), Vannas scissors (single-use), LASIK spatula with flat sharp tip (reusable)
- 10 ml syringe with BSS, blunt blue cannula
- 5 ml syringe half-filled with BSS, LASIK cannula
- LASIK spatula
- Marker with dye
- Bandage contact lens (unsterile)
- Soaked in Dexafree eye drops 2x and Floxal eye drops 2x for 30 minutes
Surgical procedure
Disinfection of the eyelids, eyelashes, and conjunctival sac with Betadine® solution (diluted 1:8) — covering the eyelashes with sterile adhesive drape and inserting the lid speculum. Topical anesthesia with Oxybuprocaine® eye drops and laser creation of a 9.5 mm LASIK flap using the femtosecond laser at a depth of 110 µm, hinge at 12 o'clock. Cleaning of the cornea with a triangular swab, then marking the flap edge. Lifting the LASIK flap with a LASIK spatula. Stromal ablation is then performed with the excimer laser according to the desired refraction. The LASIK flap is repositioned. Irrigation under and over the LASIK flap until it is completely free of debris. Smoothing of the flap with the triangular swab. Insertion of a bandage contact lens loaded with Floxal® and Dexafree® eye drops. The same procedure is performed on the contralateral eye with a separately sterilized LASIK set.
Postoperative
- Analgesia (caution: adjust as needed for body weight and liver/kidney values)
- Paracetamol 500 mg tablet 4x/day up to 8x/day (e.g. Dafalgan®)
- Non-steroidal anti-inflammatory drug (e.g. mefenamic acid 500 mg tablet 3x/day or ibuprofen 400 mg tablet 4x/day)
Follow-up plan
- Day 1: Remove contact lens (caution: carefully, from inferior with a cotton-tip applicator or with fine anatomical forceps from the temporal side, with the patient looking nasally)
- Start FML eye drops 3x/day for 1 week, 2x/day for 1 week, 1x/day for 1 week
- In case of erosion (at the flap edge): Floxal eye drops 4x/day and follow-up every two days until epithelial closure, only then start FML eye drops
- Showering is possible again, no water or shampoo in the eye, no sauna/steam bath/swimming pool etc., do not rub the eye, eye shield at night
- Return for re-evaluation if vision worsens
- DLK (diffuse lamellar keratitis) -> urgent consultation with the surgeon
- Epithelial ingrowth or foreign body in the interface -> consultation with the surgeon
- Striae (folds in the flap) -> urgent consultation with the surgeon -> smoothing out at the slit lamp
- 1 month
- Topography (ectasia?)
- Slit lamp (epithelial ingrowth?)
- Subjective visual acuity
- All activities possible again, including eye rubbing; follow-up if visual acuity worsens or glare occurs
- 12 months
- Topography (ectasia?: myopic shift, astigmatism, posterior float)
- Slit lamp: corneal punctate staining in dry eye -> lubrication/cyclosporine eye drops/punctal plugs
- Subjective visual acuity
Miscellaneous
- Costs for follow-up visits and eye drops are included in the surgery price for self-paying patients (not for enhancement/touch-up after cataract surgery)
- For sterile infiltrates in the interface (DLK 1)
- DLK 1 (fine whitish granular cells, optical axis clear): increase topical steroids and close follow-up
- Increase topical steroid therapy
- Close follow-up (caution: may take several days until the cornea clears completely)
- DLK 2 (optical axis also affected, typical "Sands of Sahara")
- Intensified topical steroid therapy
- Close follow-up (daily)
- DLK 3 (dense, clumped central cell accumulation, also centrally -> critical stage)
- Emergency flap relifting and irrigation of the interface
- DLK 4 (central striae/bullae, stromal melting and scarring -> irreversible)
- If infectious infiltrates are suspected
- Floxal eye drops and Tobrex eye drops alternating hourly, Floxal eye ointment at night
- Photo documentation and inform the surgeon
- Visual acuity improves within the first three days
- Re-treatment after LASIK at the earliest 3 months after the procedure, once topography and refraction are stable
