This document discusses LASIK complications and their management. It describes potential intraoperative complications such as incomplete cuts, thin cuts, and free caps. Early postoperative complications include flap-related issues like displacement, wrinkling, and striations. Late complications include epithelial ingrowth, diffuse lamellar keratitis, microbial keratitis, and corneal ectasia. Refractive complications like irregular astigmatism, undercorrection, overcorrection, regression, and ectasia are also reviewed. Prevention and management strategies are provided for each complication.

1. LASIK: COMPLICATIONS AND
THEIR MANAGEMENT
Dr. Rujuta GoreDr. Rujuta Gore
Dr. Mrudula BhaveDr. Mrudula Bhave

2. LASIK: Possible complications
Intraoperative
Microkeratome related
Flap related
Early postoperative
Late postoperative
Refractive complications

3. Intraoperative complications
Inadequate exposure
Inadequate suction

4. Incomplete Cut
A lamellar cut that does not reach the limit scheduled by
the operating program
Causes:
Loss of suction
Block of keratome by drape or dust in its gears
Power failure
Prevention:
Precise preoperative check of the instrumentation
Adequate exposure
Continuous power supply

5. Mx Incomplete Cut
Unexpected stop- reverse the run direction, remove the
suction ring
Complete block- suspend the suction, gently remove
microkeratome and suction ring in a direction away from
hinge
Sufficient room for refractive ablation- proceed
If insufficient- replace the flap; postpone by 3-6 months

6. Thin/ Perforated cut (buttonhole)
Mechanical Causes:
Inadequate suction
Incorrect ring size
Poor blade quality
Excessively dry cornea
Loose epithelium
Edematous epithelium
Anatomical causes:
Very steep corneas
Irregular astigmatism

7. Results:
Inability to perform laser ablation
Risk of epithelial ingrowth in interface and possible
melting
Risk of irregular astigmatism

8. Mx Thin Cut
Prevention:
Avoid excessive use of anaesthetic eyedrops that may weaken
the epithelium
Change the blade after every cut
If flap can be raised, ablation can be performed, paying
attention to alignment, avoiding folds while repositioning

9. Mx Thin Cut
Management:
Minimal manipulation
Replace the thin flap or buttonholed flap while carefully
managing the epithelial edge
Inspect the flap and verify adherence
Wash the interface carefully
Therapeutic contact lens

10. Flap cut around 360° (Free Cap)
Etiology-
Large (>14.5mm) , flat cornea
(<41.0D)
Poor assembly of microkeratome
Inadequate suction
Removal of suction ring with cap
still adhered to it
Reduced intra op IOP
Prevention:
Corneal marking for proper
alignment

11. Mx Free Cap
Keep the flap in antidessication chamber, epithelial side
down
Proceed with ablation
Stromal surface should not be hydrated
Align flap with preop markings
Sutures not required
OR Flap may be discarded; apply a contact lens to aid
epithelial regrowth

13. Early Postoperative
Complications

14. Flap related complications
Causes:
Excessive dehydration due to prolonged surgical time
Manipulation with forceps, swabs and other instruments
not suitable for LASIK
Prevention:
Alleviate anxiety
Flap must not be allowed to dry
Time between lifting and reposition minimum
Avoid excessive interface irrigation
Speculum removal-gentle
Protect the hinge when OZ is large

15. Flap Complications
Displacement of flap
Wrinkled flap (micro and macrostriations)
Interface debris
Flap edema
Flap shrinkage
Flap stretching
Decentration

16. Displacement of flap
Causes:
Incomplete adhesion to stroma
Squeezing of eyes while drape and
speculum removal
Excessive movements of eye/
rubbing
Dryness of eye
Accidental trauma while instilling
drops
Mx:
Immediate refloating of flap into
position

17. Wrinkled flap
Causes:
Rubbing
Instilling eyedrops
Incorrect flap positioning
Extremely thin flap
Dehydration of stromal
surface due to prolonged
exposure
Rough handling of flap
Use of vasoconstricting
agents like phenylephrine
or brimonidine to
minimize SCH

18. Striations: What are they?
Microstriations: folds in Bowman’s membrane. Cause
minimal visual deficit
Macrostriations: folds in the flap. Reduce VA due to
irregular astigmatism, halos, starbursts

19. Mx Striations
Micro- can be observed
Macro- Flap should be lifted again, interface should be
washed and flap replaced
Flap should be smoothed with a Merocel soaked in BSS,
perpendicular to orientation of striations
Contact lens may be applied

20. Striations: consequences and Mx
Striae become permanent as epithelium fills the spaces in
the folds
Mx
Soak the epithelial surface by instilling distilled water. This
creates edema and loosens the cells for removal
Remove the epithelium with a spatula
Then raise the flap and irrigate the interface with BSS, and
distilled water
Reposition
Apply contact lens

21. Persistent striations
May apply continuous 10-0 Nylon suture to mechanically
smoothen the flap
PTK to remove epithelium between striae
PTK (10μm) on stromal surface of flap

22. Interface debris
Causes:
Debris from cannula, syringe, microkeratome, sponge
Mx:
Inspect the interface and flap before removing drape
and speculum
Edge irrigation
Lift flap and reposition after irrigation

23. Microbial Keratitis
Rare but potentially devastating complication
Incidence: 1:5000(0.02% to 1%)
Common organisms:
Staph aureus (early onset infections)
Mycobacterium chelonae (late onset infections)
Candida, Fusarium (later onset)
Predisposing factors:
Poor steririlization
Poor compliance to postop instructions
Poor hygiene

24. Symptoms:
Increased light sensitivity
Pain
Redness
Foreign body sensation
Decreased vision
Microbial Keratitis

25. Clinical signs:
Corneal infiltrate
Epithelial ingrowth
Epithelial defects
AC reaction
Hypopyon
Microbial Keratitis

26. Laboratory tests:
Scrapings: from stromal bed
Smears
Culture
Management:
In case of interface infiltrate, lifting of flap and removal of all
infective foci
Irrigation with 50mg/mL vancomycin or 35mg/mL amikacin
Intensive fortified antibiotic and antifungal therapy as per
the lab results
Mx Microbial Keratitis

27. In cases of resistant bacterial infection, flap removal and
intensive medical therapy has been found useful
In cases of resistant fungal infection, an aggressive
approach consisting of amputation of the flap, daily
debridemant of the bed, intensive topical and systemic
antifungals may be required
Eyes not responding to medical therapy and those
presenting late with large infiltrates may need ALK or TPK
Mx Microbial Keratitis

28. Prevention:
Treatment of blepharitis preoperatively
Sterile technique
Careful clearing of all cannulas and syringes using fresh
sterile distilled water
Prophylactic postop topical antibiotic
Avoid swimming for 1month postoperatively
Microbial Keratitis

29. Diffuse lamellar keratitis
Also known as ‘Sand of Sahara’
Non infectious complication
Infiltration of inflammatory cells in interface

30. Possible causes:
 Retained meibomian secretions
 Metallic debris
 Talc from gloves
 Lubricants on the microkeratome or blades
 Topical medications such as anesthetics
 Endotoxins
 IL 1 released from corneal epithelial cells following cell
injury or death

31. Linebarger staging of DLK
Stage 1
Fine white cells of granular appearance distributed in
wave like fashion in periphery of flap
Frequently occurs on day1
No decrease in BCVA
Mx:
Frequent
administration of
topical steroids

32. Stage 2
Whitish cells of granular or wave like appearance in
visual axis and possibly at the periphery
Typically seen 2 or 3 days post Lasik
No decrease in BCVA
Mx:
Frequent
administration of
topical steroids
Linebarger staging of DLK

33. Stage 3
Increased density of cells in visual axis, more clumped
than wave like
Transparent peripheral cornea
Seen on day 3 0r 4
Patient may describe fogginess of vision
Linebarger staging of DLK
Mx:
Raise the flap and
thoroughly irrigate
with BSS
Frequent
administration of
topical steroids

34. Stage 4
Central corneal melting at interface by release of
collagenase by aggregated inflammatory cells
Scarrings and folds in visual axis
VA is decreased, hyperopic
shift
Irregular astigmatism
Mx:
When repair process has
concluded, consider anterior
lamellar keratoplasty
Linebarger staging of DLK

35. Late Postoperative
Complications

36. Epithelialization of interface
Causes:
Prolonged manipulation
of the flap
Excessive use of
instruments at the
interface
Poor flap edge adhesion
Epithelial abrasion at
flap edge
Flap misalignment
Buttonholes
Spillover of ablation at
bed margin

37. Results:
Decreased visual acuity
Irregular astigmatism
Discomfort
Risk of stromal melt

38. Machat classification of Epithelial Ingrowth
Grade 1:
Small white aggregates with
smooth outlines
Limited to 2mm from the
flap edge
Often outlined by white
demarcation line along the
front of epithelial
progression
No treatment required
Normally disappear within
2-4 months

39. Grade 2:
Pearly white aggregates
with blurred edges
Located within 2mm
from the flap edge
Ingrowth is thicker
My progress toward
centre of pupil
Requires observation
Machat classification of Epithelial Ingrowth

40. Grade 3:
Ingrowth is marked with
multicellular thickness
Extent exceeds 2mm from
the flap margin
Thinning or melting of flap
may occur
Machat classification of Epithelial Ingrowth

41. Prevention:
Avoid prolonged manipulation of flap
Clear any epithelium, tags, or debris from stromal bed
prior to flap reposition
Shield hinge area
Apply contact lens when epithelial defects are observed
Femtosecond laser flap is better

42. Mx
For peripheral few aggregates: NdYAG laser
30-40 pulses; 0.6-1.2mJ; beam focussed slightly
posteriorly with respect to the epithelial growth
Sufficient for blocking progression

43. Mx
For extensive aggregates:
Raise the flap closest to epithelial growth
Debride the stromal surface and undersurface of flap edges
with microspatula
In severe ingrowth with melting and folds it is better to
remove the flap and allow healing

45. Refractive Complications

46. Irregular astigmatism
Causes:
Wrinkles or folds in flap
Interface debris
Epithelial ingrowth
Decentration
Results:
VA decreased by 2 or more lines
Mx:
Retreatment is directed to underlying cause

47. Undercorrection
There is residual, unexpected refractive error in first
postoperative month
More frequent in high myopia above 10 to 12D
It is easier to correct residual myopia than to correct
hyperopia from overcorrection

48. Causes of undercorrection:
Incorrect preoperative refraction (most common)
Difficulty in performing precise refractive
evaluation(severe myopia with staphyloma)
Incorrect laser calibration
Environmental condition in OT
Incorrect data entry
Incomplete or decentered ablation
Incorrect interpretation of nomogram
Unstable ametropia
Undercorrection

49. Mx:
 Retreatment should be considered 2 to 3 months
later, after refractive stability
 Preferably under aberrometric guidance
Options:
 Lifting the flap and reablation
 Usually performed within 3 to 4mths of first treatment
 Lamellar technique or recutting a new flap(for
myopia greater than 10D)
 Performed atleast 6months after initial treatment
 May not be possible due to already thinned cornea
 Surface ablation technique(PRK)

50. Overcorrection
1 month after surgery ,there is refractive correction
that exceeds the expected value
Causes:
Incorrect preoperative refraction
Incorrect data entry
Poor control of humidity levels in laser room(too
dry)

51. Mx:
 Lifting the flap and reablation
 It is possible to repeat the treatment for hyperopic
values in 2 to 3months
 Paraperipheral ablation of anterior stromal bed is
done
 Hyperopic surface photoablation
 Hyperopia of 1 to 3D can be corrected
 Conductive keratoplasty

52. Regression
Indicates that the refractive result of Lasik is not
stable with continuing loss of effect over a few
months
Normally stops between 1 and 3 mths after surgery
More frequent in myopia >10D
Frequently seen in severe hyperopia and astigmatism

53. Causes:
May be due to combination of epithelial hyperplasia
and remodeling of stroma
Management:
Treatment options as for undercorrection
Enhancement procedures to be considered only after
refraction is stable
Regression

54. Corneal Ectasia
Progressive relaxation of
the cornea with an
increase in radius of
curvature along with
thinning
Progressive deterioration
of patient’s VA

55. Pathophysiology:
Collagen fibres in anterior third of cornea have greater
tensile strength
In LASIK, cut is performed in the anterior third
Corneal weakening by 0-33%
Ectasia: delamination and interfibril fracture
Corneal Ectasia

56. Risk factors-
Keratoconus
Pellucid marginal degeneration
Forme fruste keratoconus
Residual stromal bed less than 250μm in diseased corneas
Refractive instability and family history of keratoconus
should arouse suspicion
Corneal Ectasia

57. Results:
Thinning and bulging of cornea
Myopic shift
Irregular astigmatism
Reduced UCVA and BCVA
Corneal Ectasia

60. Diagnostic criteria for corneal ectasia:
1. Inferior topographic steepening of >5D compared with
immediate postoperative appearance
2. Loss of >2snellens line of UCVA
3. Change in manifest refraction >2D(sph/cyl)
4. Posterior float higher than 0.08 mm
Corneal Ectasia

61. Prevention:
Alternative approach- PRK/ Phakic IOL
Preoperative:
Topography:
In asymmetric cornea –test should be repeated several times
CL wearers should stop using CL 2-3wks before topography
Rule out keratoconus
Pachymetry:
Most important to plan ablation
Corneal Ectasia

62. Intraoperative:
Measure flap thickness and posterior stroma during
surgery, both before and after the ablation
Corneal Ectasia

63. Mx:
Collagen crosslinking
RGP contact lens
Intrastromal rings
Lamellar keratoplasty
Penetrating keratoplasty
Corneal Ectasia

64. Decentered Ablation
Causes:
Poor patient fixation due to
nervousness or
oversedation
Difficulty seeing target due
to blurred vision(high
corrections)

65. Results:
Loss of BCVA
Irregular astigmatism
Night vision problems
Ghosting, glare
Decentered Ablation

68. Treatment:
For mild degrees of decentration, a small diameter
ablation may be performed at the edge of the original
optical zone to enlarge the optical zone in pupillary axis
A series of 3 small diameter ablations may be placed at the
edge of decentered ablation followed by PTK smoothing
Decentered Ablation