Transcript LASIK Complication

LASIK Complication
A. Al-Muammar
LASIK Complication
Intraoperative
 Poor exposure
►Deep
orbit, small eye, narrow palpebral fissure,
drape, and lid speculum
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Difficulty in placing suction ring
Lid injury
Poor centration during laser ablation
Water pooling
►Lateral
canthotomy, facial nerve block, retrobulbar
block, converting to PRK, or abandoning surgery
LASIK Complication
Intraoperative
 Inadequate suction
►Good
suction ( IOP > 75 mmHg) would provide
depth control during microkeratome pass
►Poor or broken suction can result in thin,
buttonholes, or free cap
►Inadequate suction can be due to suction ports
clogging by debris, drape, speculum, chemotic or
redundant conjunctiva, or defect in suction line
LASIK Complication
Intraoperative
 Flap complication
►Thin
flap
 The incidence of thin flap reported to vary between 0.3%
and 0.75%
 Flap considered to be thin when keratome cuts within or
above Bowman’s layer
 Recognized by shinny reflex on the stromal surface
 It tends to occur with flat cornea or poor suction
 Reposition the flap and abort the procedure
 Deeper flap (20-60 micrm) maybe recut 10-12 weeks
LASIK Complication
Intraoperative
►Buttonholes
flap
 A buttonholed flap occurs when microkeratome blade
travels more superficially than intended and enters the
epithelium/Bowman’s complex
 Buttonholes maybe partial thickness if they transect
Bowman’s layer or full thickness if they exit through the
epithelium.
 The incidence of buttonholes ranges between 0.2% and
0.56%
 Buttonholes flap tend to occurs in case of steep cornea >48
D, resistance to cutting, or lack of synchronization between
keratome movement and oscillatory blade movement
LASIK Complication
Intraoperative
►Tx
 Reposition the flap
 And wait 3 to 6 months before recutting
 Transepithelial PRK within 2 weeks
LASIK Complication
Intraoperative
 Irregular flap
►Abnormal
shape/diameter/ or thickness flap
►Result from damaged microkeratome blades,
irregular oscillation speed, or poor suction
►Incidence 0.09%-0.2%
►Reposition the flap and abort the procedure
LASIK Complication
Intraoperative
►Incomplete
flap
 Created when the microkeratome blade comes to halt prior
to reaching the intended location of the hinge
 Incidence ranges between 0.3% and 1.2%
 Microkeratome jamming due to either electrical failure or
mechanical obstacles as lashes, drape, or loose epithelium
 Unless enough space exists for ablation( 1mm space
between ablation and the edge), incomplete flap are best
managed by immediate repositioning and postponing the
procedure
LASIK Complication
Intraoperative
► Free
flap
 Unintended free flap can occur with corneas flatter than 38D
prior to surgery, poor suction, or migration of suction ring.
 Recent studies report an incidence between 0.01% and 1%
 If the flap is not visible on the surface of the cornea, then the flap
could be inside the microkeratome head
 Marking the cornea prior to surgery is very important for proper
placement of free flap
 If the cap has normal thickness and diameter, the ablation can
still be performed. Flap repositioned using placed marks. A BCL
applied to tamponade the cap. Suturing rarely necessary
 Abnormal thin/irregular flap which is the usual case should be
repositioned using sutures, and laser should be delayed
 Early removal of sutures is important to minimize scarring
 If the flap cant be retrieved, epithelium is allowed to heal as in
PRK
LASIK Complication
Intraoperative
►Decentered
flap
 Flap decenterations are attributable to an inexperienced
surgeon improperly aligning the suction ring with the limbus
or migration of the ring on the corneal surface when suction
applied
 Most surgeon will not proceed with laser unless the ablation
can be placed 1 mm of the bed is left between the ablation
peripheral bed and the flap margin
 The Introduction of microkeratome with large diameter flap
have reduced this problem
LASIK Complication
Intraoperative
►Corneal
perforation and anterior segment damage
 Result from error in placing the plate that control the depth
of the cut into instruments
 Newer designs have eliminated the potential for these
severe complications since they have a fixed depth plate
and components of the microkeratome cannot be inserted
incorrectly.
LASIK Complication
Intraoperative
►Intraoperative
bleeding
 Corneal neovascularization from pannus, decentered flap,
and large flap are the most common causes of
intraoperative bleeding
 Topical vasoconstrictors can be applied 3 to 5 minutes prior
to surgery in high risk group
 Tamponade any bleeding prior to flap lifting
 Any blood that might interfere with laser should be
irrigated
LASIK Complication
postoperative
►Epithelial
complication
 Incidence reported to be around 5%
 Epithelial defects more common in patients with abnormal
epithelial adhesion as in EBMD, or patient with who develop
epithelial defect in the first eye
 Mild staining at the edge of the flap is common
 Large defects are worrisome especially those with
connection to the flap edge
 Epithelial defect can increase the risk of infection, epithelial
ingrowth, and DLK
 Treated with BCL, or patch
LASIK Complication
postoperative
►Pain
 Most patients experience only mild discomfort following
LASIK
 Severe pain may herald more severe complication such as a
displaced flap, DLK, or infection
LASIK Complication
postoperative
►Flap
striae and wrinkles
 Reported incidence between 0.2% and 1.5%
 It is related to the disparity between the curvature of the
posterior surface of the flap and the bed following
complication
 Large thin flap, improper BCL placement, removal of lid
speculum, and eye rubbing can increase the risk of striae
 Striae can be micro or macro. Retroillumination and
fluorescein can help in detecting striae
 Visually significant striae should be treated as soon as
possible to avoid fixed striae
 LASIK flap iron, lifting the flap =/- suture, and PTK are
possible options to treat striae
LASIK Complication
postoperative
►Displaced
flap
 Emergency, should be repositioned as soon as possible to
prevent infection, fixed folds, and epithelial ingrowth
 Incidence have been reported to be 1.1% and 2% (old
reports)
 Usually occur in the first 24 hrs after surgery
 Eye lid rubbing, squeezing, and trauma especially with
large thin flap are the main predisposing factor for
displaced flap
 Flap should be reflected, examined for epithelial cells or
debris which should be scraped, the reposition the flap and
apply BCL
LASIK Complication
postoperative
►Epithelial
ingrowth
 Reported incidence vary between 1% and 2%
 Possible mechanisms
► Mechanical dragging by keratome blade during
keratectomy
► Backflow during irrigation carrying floating epithelial
cells
► Ingrowth at the junction of the epithelium and
keratotomy
► Implantation with instruments
► Cell migration through epithelial defect
LASIK Complication
postoperative
 Complications
► Decrease visual acuity
► Anterior stromal melt
 Treatment
► Flap lifting
► Irrigation
► Scraping
► Alcohol
► PTK
► MMC
► suture
LASIK Complication
postoperative
►lamellar
interface debris
► Oil
► Mucous
► Particles
from the sponge
► Metallic fragments from the Blade
► RBC
► Powder from gloves
► Lint fibres
► Lashes
 Peripheral debris which not associated with keratitis or
neovascularization can be left undisturbed
 Central debris should be removed
LASIK Complication
postoperative
► Diffuse
Lamellar Keratitis (DLK)
 Diffuse non-infectious inflammation at the level of the interface during the
first few days after LASIK
 Reported incidence is highly variable, between 0.2% and 3.2%
 Possible causes, most of these are based on speculation without
supporting data
► Betadine
► Impure BSS
► Retained meibomian secretions
► Metallic debris
► Talc from gloves
► Thermal effect from the laser
► Lubricants on the microkeratome or blades
► Topical medications such as anesthetics
► Bacterial cell wall components (lipopolysaccharides)
► Endotoxins
► IL 1 released from corneal epithelial cells following cell injury or death
LASIK Complication
postoperative
 Stages
► Stage I seen on day 1 as white, granular cells in the
periphery with sparing of the visual axis.
► Stage II seen on day 2 or 3, shows white cells in the
visual axis
► Stage III involves an aggregation of cells clumped in
the visual axis and associated with haze and reduce
vision
► Stage IV involves central stromal necrosis, melt, and
secondary hyperopia with irregular astigmatism
LASIK Complication
postoperative
►Tx
 Stage I and II, should be treated with intense topical
steroid every 1 hr
 If inflammation progressed even with steroid or patient
presented with stage III or IV
► the flap should be lifted
► Cleaning
► profuse irrigation
► Culture for bacteria and fungus
► Topical steroid =/- oral steroid
► PTK/HCL
LASIK Complication
postoperative
► Infection
 Infectious agents that have been reported after LASIK include
► Virus
► Bacteria (including atypical mycobacterium and nocardia)
► Fungus
► Parasite
 If infiltrate noted, it should be treated as infectious until proven
otherwise
 Infiltrate should be cultured …bacteria, fungus, acanthameoba,
Ziehle-Nelson stain
 Tx
► Abx
► Antifungal
► Antiviral
► Flap removal
LASIK Complication
postoperative
►Dry
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eye
Neurotrophic in origin
Worse in patient who are known to have dry eye
Present with PEE and visual fluctuation
May last 6 to 8 months
Tx
► Tears
► Punctum plug
LASIK Complication
postoperative
► Corneal
ectasia
 Iatrogenic keratoconus like condition
 Minimum stromal bed thickness of 250-300 microm should be left
after laser ablation
 Present as progressive myopia, or decrease visual acuity
secondary to irregular astigmatism
 Dx
► Orbscan
► Pachymetry
 Tx
► RCL
► Corneal
► PKP
ring
LASIK Complication
psotoperative
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Decentration
Irregular astigmatism
Glare, and haloes
Overcorrection
Undercorrection