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Known and Potential Complications of SMILE
Walter Sekundo
Philipps University Marburg/Germany
The author have no financial interest in any topics related to this study. Prof. Sekundo is a member of the scientific board of Carl Zeiss Meditec AG
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2
pre-laser cut
• Failure to obtain an adequate suction
• Correct treatment pack size (S in myopic cases)
• Use speculum with suction
• VisuMax internal settings o.k.? (Hotline)
3
• Watch the 1st Purkinje projection (obeservation mode) • Apply suction after ≅ 85-90% applanation
• Do not apply suction > 3 times
*Lazaridis & Sekundo, JRS 2014
pre-laser cut
Decentration (mm) from corneal apex
16
42
10
1
9
35
23
2
0
5
10
15
20
25
30
35
40
45
0-0,2 0,2-05 0,5-1 >1
• ReLEx • Fs-Lasik
24
32
12
1
9
28 31
1 0
5
10
15
20
25
30
35
0-0,2 0,2-05 0,5-1 >1
Decentration (mm) from pupil centre
4
Pre-operative
• Centration: minor nasalisation is normal (angle κ)
*Lazaridis & Sekundo, JRS 2014
ReLEx Mean Decentration: 0.326mm Nasalisation of the fixation in relation to the pupil centre = positive angle κ
fs-LASIK Mean Decentration: 0.452mm Centration is randomly distributed
-1,50
-1,00
-0,50
0,00
0,50
1,00
1,50
-1,50 -1,00 -0,50 0,00 0,50 1,00 1,50
OD, OS
-1,50
-1,00
-0,50
0,00
0,50
1,00
1,50
-1,50 -1,00 -0,50 0,00 0,50 1,00 1,50
OD, OS
• Control of cyclorotation is a problem unless adjusted manualy by Contact Glass rotation
5
• Suction loss
• intermittend laser stop (fluid in interface)
• Poor dissection
• Incomplete cut (e.g. incomplete sidecut)
During laser cut
6
Suction loss: 3.2%*
1.Convert to ReLEx FLEx or continue with SMILE with a larger cap, if the bottom plane has been accomplished
2. Abort procedure, if „suction loss“ occurred during the first cut: perform microkeratome Lasik or PRK with MMC or phakic IOL later
3. A vertical opening cut is possible at any time
4. Software „flap making tool“ can be used later in time
1) Lamellar ring 2) Overlap 3) Side Cut with Hinge
Hinge width
Coutesy of R.Shah
VisuMax® software assists you in decision making:
* Wong CW et al , JCRS 2014
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• Epithelial slugh off (basement membrane dystrophy): Contact lens, steroids (DLK!)
• Cap perforation & tear: I usually use >120µm cap, adapt and leave: usually heals well
• Tear at the incision site for SMILE: usually not a big problem
• Incomplete side cut: always keep a micro-blade in the OR
• „Wrong plane“: - use „hook movement“ from anterior lip
or invert the edge (incisions >3.5mm) - separate from distal end with Mehta reversed
dissector*
Dissection
tear
*Liu Y-C, Pujara T, Mehta JS, PLOS One 2014 8
Microstriae after SMILE?
• ReLEx SMILE does not induce any microstriae in the cap when examined by slit-lamp, unless stained with fluorescein (D. Reinstein)
• Manual stretching + ironing toward the periphery at the conclusion of procedure helps
I
BLMD Grade 2
BLMD Grade 0
* Messerschmidt-Roth & Sekundo 2013
Bowman‘s Layer Microdistorsions (BLMD)
• can be detected by OCT after SMILE • correlate with the extent of correction* • BLMD do not produce visual symptoms in the mid-term
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Post-op 1. Epithelial plug
2. Lenticule "left-overs" and debris in the interface
3. DLK
4. „Haze" in the interface
5. Ectasia
6. Infection 7. Unusual cases
10
• Always only a plug (so far) • Observe • Intervene only if progressive • Put a stich
Epithelial ingrowth
11
• Very serious complication, if – Within optical zone (more
prone in hyperopic treatments) – Usually at the edge in myopic
treatment • Irregular astigmatism • „Central island“ in hyperopia
treatment (experimental) – Dissect from the middle
toward the periphery, respect counter-action
– Use curved dissector – Use forceps only after
complete dissection
Lenticule remains
Courtesy J. Gertnere
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• Usually at the edge • Do not affect vision • Consider a longer course of
steroids to prevent local inflammation
Debris
Courtesy J. Gertnere
13
• DLK – Incidence 1.6%*
• erosion at the opening incision • thin lenticules ≈ 100µm
– Use steroids vigorously
• Haze – After DLK – As „primary scarring“ – Usually does not affect vision – Consider a longer course of
steroids (e.g. FML) after difficult dissection
Haze/DLK
Courtesy J. Gertnere
*Zhao J et al, JCRS 2015
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• Decentration (has been discussed above): never saw clinical significance. Otherwise topography guided excimer ablation (Ivarsen et al.)
Decentration
Courtesy J. Gertnere
My worst case
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Ectasia
Courtesy J. Gertnere
True ectasia: only one case reported after FLEx (Blum M. et al). Misdiagnosed form fruste Keratoconus: CXL done
Ectasia secondary to forceful dissection („via falsa“): RGP, DALK, if CL intolerance
• Infection: no reports in the literature, but
probably not very different from fs-Lasik • *Simultaneous uneventful SMILE for -6D
• Post-op UDVA
• OD=0.8
• OS=1.4
• Deterioration of vision OD
• Unchanged OS
* Courtesy of K. Shimizu, Kitasato University/Japan
Infection/unusual cases
DDx: 1) Pressure induced interlamellar keratitis 2) low grade infection
CDVA=0.4 (-3.75 cyl -3.00 Ax10) IOP = 9.7 mmHg, IOPcc = 27 mmHg
Edema and interface fluid collection
Shimizu, Kitasato University/Japan
Courtesy Prof Shimizu
3/12 post-op
CDVA=0.5 (-3.75 cyl -3.00 Ax 10) IOP = 9.0 mmHg, IOPcc = 20.9 mmHg
Residual edema and interface fluid collection
2/52 after re-intervention
Shimizu, Kitasato University/Japan
Courtesy Prof Shimizu
2/52 after 1) Pocket irrigation 2) Steroids discontinued 2) IOP lowering medication
19
Conclusion
• Despite its novelty, complications after SMILE are rare, even with new users
• In the vast majority they are similar to fs-Lasik and can be addressed accordingly
• However, SMILE requires more manual work and has a steep learning curve
• Surgeons novel to this technique should stick to the suggested training protocol
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