LASIK Complications. Anastasios John Kanellopoulos, M.D. Associate Professor NYU Medical School Director, LaserVision.

Transcription

1 LASIK Complications Anastasios John Kanellopoulos, M.D. Associate Professor NYU Medical School Director, LaserVision.gr Eye Institute

2 LASIK Adverse events Damage to epithelium 7 (0.5%) Epithelial Defect 8 (0.6%) Free Cap 54 (4.2%) Oval keratectomy 9 (0.7%) Small Flap 2 (0.2%) Small Flap with Thin Flap 1 (0.1%) Surgery Aborted : Inadequate Flap 2 (0.2%) Thin Flap 4 (0.3%)

3 LASIK Potential Microkeratome Related Complications Intraoperative Non Sight- Threatening Inadequate suction Incomplete pass Free cap Bleeding panus Torn epithelium Interface deposits De-centered flap Dislodged flap during speculum removal

4 LASIK Potential Microkeratome Related Complications Intraoperative Sight-Threatening Thin flaps Buttonholes Loss of suction, torn and irregular flaps Perforation of the cornea, loss of intraocular contents Lost caps Vascular occlusion, optic nerve damage (glaucoma patients)

5 LASIK Potential Post Operative Complications Flap striae Dislocated Flap Diffuse Interface Keratitis Infection Epithelial Ingrowth Retinal detachment

6 Prevention and Management of Microkeratome-Related Complications Incomplete Pass Jamming of the microkeratome Obstruction of the microkeratome path (drape, cilia, lid) Inappropriate setting of the <<stop>> mechanism, or inadvertent halting or reversal motion of the microkeratome If the microkeratome jams during its passage across the cornea, and the flap is incomplete, the flap is replaced and the procedure cancelled and rescheduled 3 months later

7 Prevention and Management of Microkeratome-Related Complications Loss of suction Incomplete, torn, or irregular flaps Photoablation is usually not possible Replace flap and wait 6 months Increased risk of epithelial ingrowth Sutures should be avoided, whenever possible, for they may result in irregular astigmatism, and they should be removed in the first postoperative week

8 Prevention and Management of Microkeratome-Related Complications Torn epithelium Inadequate lubrication of epithelial surface prior to microkeratome pass Underlying basement membrane disorder May result in flap edema, delayed visual rehabilitation and flap striae Replace flap and reposition epithelium Best treates with bandage contact lens (avoid premature removal) PRK for patients with identifiable anterior basement membrane dystrophy

9 Free Cap Prevention and Management of Microkeratome-Related Complications Inadequate amount of cornea presenting through the suction ring (such as when the keratometry is 40D) Hinge setting is too small May be possible to complete the photoablation, and to replace the cap without sutures. Preplaced gentian violet marks on the corneal surface may help in proper orientation of the flap NO EYE RUBBING FOR AT LEAST 2 WEEKS

10 Prevention and Management of Microkeratome-Related Complications Vascular Occlusion With appropriate suction, IOP rises to a level which occludes the central retinal artery Prolonged occlusion may result in permanent damage of retinal nerve cells and a permanent loss of vision Diabetic, arteriosclerotic, or advanced glaucoma patients are at higher risk of potential loss of vision due to retinal vessel occlusion

11 Prevention and Management of Microkeratome-Related Complications Epithelial Ingrowth Implantation and proliferation of epithelial cells in the interface following LASIK Diffuse intraoperative spreading of cells because of careless and/or excessive manipulation of flap Postoperative peripheral ingrowth of epithelial cells starting from the edge of the flap Proliferation from the central area of the flap in specific cases such as buttonholes, LASIK after RK, or after PK

12 Risk Factors for Epithelial Ingrowth Factors which may cause minor trauma or instability of the corneal epithelium Epithelial basement membrane dystrophy, recurrent epithelial erosion syndrome, or diabetes. Excessive use of topical anesthetics Betadine scrub on the corneal surface Excessive manipulation and/or drying of the corneal epithelium Laring of epithelium at edge of flap (hyperopia)

13 Risk Factors for Epithelial Ingrowth Serious intraoperative or early postoperative complications: Buttonhole, thin or irregular flap Secondary flap displacement Peripheral intraoperative epithelial defect which may decrease efficacy of endothelial pump and flap adhesion Previous corneal surgery Enhancements, RK, PK

14 Epithelial Ingrowth Clinical Presentation Occurs within days to weeks following LASIK Mild:usually asymptomatic, diagnosed on slit-lamp examination Severe: may complain of photophobia, tearing, foreing body sensation, redness, pain, glare and halos

15 Epithelial Ingrowth

16 Epithelial Ingrowth Clinical Presentation White or gray nests of cells in the interface which may fuse into larger areas Usually located near the edge of the flap, and may progress towards the center Stromal melting may occur and cause irregular astigmatism, hyperopic shift and loss of BCVA

17 Epithelial Ingrowth Management Mild cases follow patients for progression, document with photography if necessary Surgery is required in the following cases: Progressive epithelial ingrowth Stromalmelt Location of epithelial ingrowth less than 2mm away from the visual axis

18 Epithelial Ingrowth Management Lift flap and scrape out the epithelial cells (bed and flap) Other methods have been advocated, including: Merocel sponges soaked with alcohol (alcohol may result in stromal keratocyte injury) Excimer photoablation (PTK may induce or worsen irregular astigmatism)

19 Epithelial Ingrowth Prevention Minimize intraoperative epithelial trauma Avoid excessive flap manipulation Minimize seeding when re-lifting a flap Minimize re-treatments Beware of patients with underlying basement membrane disorder

20 Flap Wrinkles (Striae) Striae are fine irregularities which may be observed postoperatively within the deep stromal surface of the flap

21 Flap Wrinkles (Striae) Diagnosis Best seen with retroillumination May be detected on immediate postop exam Usually diagnosed after 24 hours, because of significant decrease in flap edema

22 Flap Wrinkles (Striae) Pathogenesis Striae usually result from surface incongruence after the flap is repositioned : Too much hydration, or conversely, too much desiccation of the flap while it is lifted, may retract it and reduce its initial size Striae may also result from deep photoablation. The resulting modification of the stromal bed may not allow a good post-ablative congruence to the flap

23 Flap Wrinkles (Striae) Pathogenesis A short hinge may predispose the flap to rotate, which may lead to striae formation ( then usually located near the hinge) Incorrect or inadequate manipulations after repositioning the flap such as excessive painting may also result in striae

24 Flap wrinkles (striae) Management Striae will not disappear with time Mild peripheral striae are frequently observed, and do not require treatment if they are visually non-significant Central or paracentral striae must be treated if they are responsible for significant loss of BCVA

25 Flap Wrinkles (Striae) Management Lift flap Hydrate stromal surface with dripping merocel sponges for several minutes Consider hypotonic BSS (50-80%) Stretch perpendicular to the striae with cannula or similar instrument Reposition flap Stretch epithelial surface gently in the same direction with wet merocel sponges

26 Laser Related Complications Under/Over corrections Decentrations Data Entry Errors Central Islands

27 Minimizing Surgical Complications KNOW YOUR EQUIPMENT Patient preparation (no surprises) Laser use (verify all data and calibrations) Check microkeratome assembly and operation Sterilization and sterile technique Achieve adequate exposure with speculum

28 Minimizing Surgical Complications Avoid Epithelial Damage Minimize topical anesthetics, have patient close eyes, avoid pachymetry on day of surgery, careful with betadine Careful suction ring placement Centration, intentional decentration (pannus, or nasal hinge) Obtain good suction Press firmly, tonometry, monitor vision and pupil, pseudo-suction, chemosis with globe rotation

29 Minimizing Surgical Complications Before the microkeratome pass Lubricate the surface Lift globe to clear path During the microkeratome pass Jamming of the microkeratome avoid loss of suction and free cap, different causes with different microkeratomes During laser treatment Good patient fixation and laser alignment, protect hinge/flap, control bleeding

30 Minimizing Surgical Complications aspirating speculum or Chayet ring may reduce interface debris Replace flap with minimal irrigation Gently smooth epithelium to avoid striae Check flap alignment, highmag. for debris Careful speculum removal Post-op slit lamp exam Protective shield at bedtime

31 Post-operative Complications Dry Eye Syndrome Reduction in visual function May range from minimal punctate staining to confluent staining Associated with corneal dennervation Preservative free artificial tears for 2 to 6 weeks Punctal occlusion if necessary

32 Cataracts and Lasik Best diagnosed pre-op Results in dissatisfied post-op patients Caution with IOL calculation post LVC

33 Infectious Keratitis Non-tuberculous mycobacteria post LASIK

34 Infectious Keratitis Staph aureus keratitis

35 Infectious Keratitis

36

37 Epithelial Defect 1 Day post-op c/o pain and poor vision No epi defect seen immediately post-op Suspected keratolysis BCL placed Resolved in 24 hours

38 Dry Eye post LASIK

39 Buttonhole

40 Interface Debris Numerous sources of debris include airborne, microkeratome and blade, sponge, irrigation solution, meibomian gland secretions, epithelium

41 Interface Debris (meibomian gland secretions)

42 LASIK regressions Multiple factors as: Contact lens use RGPs Cold laser, Wet enviroment and/or technique

43 LASIK regressions Inaccurate pre-op Epithelial hyperplasia (10-20Microns nl) Cornea ectasia

44 Pt#1 preop 6, 2months -2

45 Pt#1 preop: 6, 2months: -2

46 Pt#1 preop 6, 2months -2

47 LASIK Regressions Even when 250 residual microns respected there may be ectasia and/or FORWARD CORNEA movement resulting in regression Flying spot lasers remove more tissue per D corrected and larger zone. May pose greater risk

48 Hypethermic Treatment for Flap Striae following LASIK A. John Kanellopoulos, MD Manhattan Eye, Ear and Throat Hospital TLC Laser Eye Centers

49 Background 2 million Lasik procedures expected in the US in 2000 Complications uncommon Flap striae can reduce UCVA, BCVA and increase glare/distortion

50 Background Flap striae usually form in the early postoperative period Traumatic ( eye rubbing ) Dry eye (poor post-operative lubrication can increase eyelid-flap traction) Deep ablations (in very high myopes) can predispose to flap striae

51 Background Hyperthermic stromal collagen treatment of degrees C, relaxes fibrils without scar formation/ or tissue constriction. This enables restoration of original stromal texture. This does not produce stromal scarring and/or stromal shrinkage Hypotonic Saline produces flap edema

52 Methods 15 LASIK patient/eyes with clinically significant striae (glare, UCVA<20/20, subjective distortion, topographic irregular astigmatism) were treated Informed consent was given in regard to the treatment method

53 Surgical technique Sterile water is heated to55 0 C, Golf-club spatula is submerged into heated water

54 Surgical technique Flap is marked and then lifted

55 Surgical technique Golf-club spatula is heated in the sterile water and used to iron out the folds from the back-side of the lifted flap Collagen and/or debris accumulation within the striae is removed both from the flap underside as well as the stromal bed

56 Surgical technique Johnston applanator heated in sterile water is used to press-iron the repositioned flap for seconds.

57 Surgical technique Care is taken to always slide away from the hinge In long term striae (over 2weeks) the epithelium is separated from the underlying flap (Long term striae produce resilient epithelial layer memory that can reintroduce the striae following treatment)

58 Postoperative Celluvisc drop to avoid eyelid-flap traction

59 Postoperative Bandage contact lens for 1 day, (3 days in cases with epithelial removal) Ocuflox/Predforte 4 times a day for 1 week Follow-up of Va, topography, biomicroscopic striae presence

60 Results Pre UCVA: 20/42, post: 20/24 Pre BCVA: 20/30, post: 20/21 Mean follow-up 5 months (4-8) No complications, no BCVA loss Dramatic topographic improvement of irregular astigmatism

61 Conclusions Hyperthermic treatment loosens collagen fibrils in wrinkled flap Hypotonic sterile water produces swelling of flap in reduction of wrinkling Combination appears effective in flap striae ironing and then press-ironing

62 Conclusions This technique is safe and appears to be quite effective for management of flap striae following LASIK Simple instrumentation required For old striae: loosening of epithelium and treatment of flap stroma separately is essential

63 Conclusions Immediately following treatment epithelial striae may persist, and must not be confused with true flap striae Epithelial striae (in recently wrinkled flaps) will subside in about a week