Preoperative assessment, patient selection and treatment ......Preoperative assessment, patient...
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Preoperative assessment, patient selection and treatment planning for a SMILE patient Glenn I Carp, MBBCh, FC Ophth (SA) 1 Dan Z Reinstein MD MA(Cantab) FRCSC DABO FRCOphth FEBO 1,2,3,4 1. London Vision Clinic, London, UK 2. Columbia University Medical Center, New York, USA 3. Centre Hospitalier National d’Ophtalmologie, (Pr. Laroche), Paris, France 4. Biomedical Science Research Institute, Ulster University, Coleraine, UK
Transcript of Preoperative assessment, patient selection and treatment ......Preoperative assessment, patient...
Preoperative assessment, patient selection and
treatment planning for a SMILE patient
Glenn I Carp, MBBCh, FC Ophth (SA)1
Dan Z Reinstein MD MA(Cantab) FRCSC DABO FRCOphth FEBO1,2,3,4
1. London Vision Clinic, London, UK
2. Columbia University Medical Center, New York, USA
3. Centre Hospitalier National d’Ophtalmologie, (Pr. Laroche), Paris, France
4. Biomedical Science Research Institute, Ulster University, Coleraine, UK
©DZ Reinstein 2016
Financial Disclosure
The author (DZ Reinstein) acknowledges a financial
interest in Artemis™ VHF digital ultrasound (ArcScan Inc.,
Morrison, CO)
GI Carp has travel expenses paid by Carl Zeiss Meditec AG
(Jena, Germany)
The author DZ Reinstein is a consultant for Carl Zeiss
Meditec AG (Jena, Germany)
Ectasia after SMILE?
©DZ Reinstein 2016
Ectasia cases reported after SMILE
Inferior Steepening No Inferior Steepening
Eccentric back surface
apex and pachymetry
Epithelial thickness map?
Ectasia after SMILE?
SMILE is Still Tissue
Subtraction
Reasons to offer LASIK
instead of SMILE
PRESBYOND Demanding Patient
Needs good vision in early
postop period
Corneal Scar
Can have LASIK as
lock & key
Treatment Planning for SMILE
Parameters
©DZ Reinstein 2016
• Reserve 2mm Small Incision
ReLEx SMILE: Lenticule Geometry
Temporal Nasal
• 6-7.5 mm Optical Zone
• 2 mm Small Incision
• 90° Lenticule Sidecut
• 8 mm Cap Diameter
• 135 µm cap thickness
©DZ Reinstein 2016
• Reserve 2mm Small Incision
ReLEx SMILE: Lenticule Geometry
Temporal Nasal
• 6-7.5 mm Optical Zone
• 2 mm Small Incision
• 90° Lenticule Sidecut
• 8 mm Cap Diameter
• 135 µm cap thickness
Advantages of a thick cap
Biomechanics Innervation Retreatment
©DZ Reinstein 2016
Anterior Stroma Stronger than Posterior
Cohesive Tensile Strength Tangential Tensile Strength
Biomechanics Retreatment
Advantages of a thick cap
Innervation
©DZ Reinstein 2016
Dry Eye Publications after SMILE • Reinstein DZ, Archer TJ, Gobbe M, Bartoli E. Corneal Sensitivity after Small Incision Lenticule Extraction (SMILE). J Cataract
Refract Surg. 2015 [In Press].
• Wei S, Wang Y. Comparison of corneal sensitivity between FS-LASIK and femtosecond lenticule extraction (ReLEx flex) or small-
incision lenticule extraction (ReLEx smile) for myopic eyes. Graefes Arch Clin Exp Ophthalmol. 2013;251:1645-1654.
• Wei SS, Wang Y, Geng WL, Jin Y, Zuo T, Wang L, Wu D. [Early outcomes of corneal sensitivity changes after small incision
lenticule extraction and femtosecond lenticule extraction]. Zhonghua Yan Ke Za Zhi. 2013;49:299-304.
• Vestergaard AH, Gronbech KT, Grauslund J, Ivarsen AR, Hjortdal JO. Subbasal nerve morphology, corneal sensation, and tear
film evaluation after refractive femtosecond laser lenticule extraction. Graefes Arch Clin Exp Ophthalmol. 2013;251:2591-2600.
• Demirok A, Ozgurhan EB, Agca A, Kara N, Bozkurt E, Cankaya KI, Yilmaz OF. Corneal sensation after corneal refractive surgery
with small incision lenticule extraction. Optom Vis Sci. 2013;90:1040-1047.
• Li M, Zhao J, Shen Y, Li T, He L, Xu H, Yu Y, Zhou X. Comparison of Dry Eye and Corneal Sensitivity between Small Incision
Lenticule Extraction and Femtosecond LASIK for Myopia. PLoS One. 2013;8:e77797.
• Li M, Zhou Z, Shen Y, Knorz MC, Gong L, Zhou X. Comparison of corneal sensation between small incision lenticule extraction
(SMILE) and femtosecond laser-assisted LASIK for myopia. J Refract Surg. 2014;30:94-100.
• Li M, Niu L, Qin B, Zhou Z, Ni K, Le Q, Xiang J, Wei A, Ma W, Zhou X. Confocal Comparison of Corneal Reinnervation after Small
Incision Lenticule Extraction (SMILE) and Femtosecond Laser In Situ Keratomileusis (FS-LASIK). PLoS One. 2013;8:e81435.
• Gao S, Li S, Liu L, Wang Y, Ding H, Li L, Zhong X. Early changes in ocular surface and tear inflammatory mediators after small-
incision lenticule extraction and femtosecond laser-assisted laser in situ keratomileusis. PLoS One. 2014;9:e107370.
• Ishii R, Shimizu K, Igarashi A, Kobashi H, Kamiya K. Influence of femtosecond lenticule extraction and small incision lenticule
extraction on corneal nerve density and ocular surface: a 1-year prospective, confocal, microscopic study. J Refract Surg.
2015;31:10-15.
• Mohamed-Noriega K, Riau AK, Lwin NC, Chaurasia SS, Tan DT, Mehta JS. Early corneal nerve damage and recovery following
small incision lenticule extraction (SMILE) and laser in situ keratomileusis (LASIK). Invest Ophthalmol Vis Sci. 2014;55:1823-1834.
• Xu Y, Yang Y. Dry eye after small incision lenticule extraction and LASIK for myopia. J Refract Surg. 2014;30:186-190.
• Denoyer A, Landman E, Trinh L, Faure J, Auclin F, Baudouin C. Dry eye disease after refractive surgery: comparative outcomes of
small incision lenticule extraction versus LASIK. Ophthalmology. 2015;122(4):669-676
©DZ Reinstein 2016
Corneal Sensation: SMILE vs. LASIK
0
10
20
30
40
50
60
-1 0 1 2 3 4 5 6 7 8 9 10 11 12
Me
an
Co
rne
al S
en
sa
tio
n (
mm
)
Time Point (Months)
LASIK (16 studies)
SMILE (7 studies)
SMILE (Reinstein)
Reinstein DZ, Archer TJ, Gobbe M, Bartoli E. Corneal Sensitivity after SMILE. J Cataract Refract Surg 2015.
Biomechanics Innervation
Advantages of a thick cap
Retreatment
©DZ Reinstein 2016
Epithelium
SMILE Enhancement: Thin Flap LASIK
+18 μm (4SD) = 118 μm
+18 μm (4SD) ≤80 μm
-18 μm (4SD) = 117 μm
Standard SMILE Protocol:
• Use minimum 135 μm cap
• Retreatment as 100 μm flap LASIK
100 μm
135 μm
Posterior Cornea
©DZ Reinstein 2016
• Reserve 2mm Small Incision
ReLEx SMILE: Lenticule Geometry
Temporal Nasal
• 6-7.5 mm Optical Zone
• 2 mm Small Incision
• 90° Lenticule Sidecut
• 8 mm Cap Diameter
• 135 µm cap thickness
©DZ Reinstein 2016
Optical Zone – Ablation/Lenticule Depth
SMILE LASIK
Optical Zone
(mm)
6.70±0.39
(5.90 to 7.00)
6.08±0.22
(5.75 to 7.00)
Ablation/
Lenticule (μm)
107±19
(72 to 149)
81±25
(25 to 134)
5.90 6.00 6.25 6.50 6.75 7.00
SMILE 2% 13% 1% 24% 2% 58%
LASIK 3% 82% 0% 13% 0% 2%
2% 13%
1%
24%
2%
58%
3%
82%
0% 13%
0% 2% 0%
20%
40%
60%
80%
100%
Perc
en
tag
e E
yes
Optical Zone (mm)
+32%
©DZ Reinstein 2016
Results: Spherical Aberration by OZ
y = -0.0807x - 0.217 R² = 0.7043
y = -0.059x - 0.1811 R² = 0.5357
y = -0.0295x - 0.0968 R² = 0.1816
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
-14.00-12.00-10.00-8.00-6.00-4.00-2.000.00
Ch
an
ge i
n S
ph
eri
cal A
berr
ati
on
(m
icro
ns)
Attempted Spherical Equivalent Refraction (D)
SMILE 6mm
SMILE 6.5mm
SMILE 7mm
Larger Zone Less SA
©DZ Reinstein 2016
Results: Spherical Aberration Increase
y = -0.0725x - 0.2621 R² = 0.4964
y = -0.0299x + 0.1543 R² = 0.154
-0.30
-0.20
-0.10
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
-9.00-8.00-7.00-6.00-5.00-4.00-3.00-2.00-1.000.00
Ch
an
ge i
n S
ph
eri
cal A
berr
ati
on
(µ
m)
Maximum Myopic Meridian Treated (D)
SMILE
LASIK
p<0.001 SMILE LASIK
Spherical
Aberration
0.11±0.16
(-0.19 to +0.51)
0.31±0.12
(-0.11 to 0.66)
-64%
©DZ Reinstein 2016
Results: Spherical Aberration by OZ
y = -0.0807x - 0.217 R² = 0.7043
y = -0.059x - 0.1811 R² = 0.5357
y = -0.0295x - 0.0968 R² = 0.1816
y = -0.0606x - 0.015 R² = 0.6601
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
-14.00-12.00-10.00-8.00-6.00-4.00-2.000.00
Ch
an
ge i
n S
ph
eri
cal A
berr
ati
on
(m
icro
ns)
Attempted Spherical Equivalent Refraction (D)
SMILE 6mm
SMILE 6.5mm
SMILE 7mm
LASIK
6mm ‘spherical’ SMILE = 6mm WFO LASIK
but less tissue consumption
6.5mm SMILE Less SA than 6mm WFO LASIK
with equal tissue consumption
7mm SMILE Even less SA
but more tissue consumption than 6mm LASIK
but still leaves the cornea stronger
Larger Zone Less SA
©DZ Reinstein 2016
• Reserve 2mm Small Incision
ReLEx SMILE: Lenticule Geometry
Temporal Nasal
• 6-7.5 mm Optical Zone
• 2 mm Small Incision
• 90° Lenticule Sidecut
• 8 mm Cap Diameter
• 135 µm cap thickness
©DZ Reinstein 2016
Use 8 mm (7.95) Cap Diameter
• Standardise parameters to minimise effect on nomogram
• Large enough to allow even a 7.5 mm optical zone
• If use Circle retreatment option, the cap is already
reasonably large
©DZ Reinstein 2016
• Reserve 2mm Small Incision
ReLEx SMILE: Lenticule Geometry
Temporal Nasal
• 6-7.5 mm Optical Zone
• 2 mm Small Incision
• 90° Lenticule Sidecut
• 8 mm Cap Diameter
• 135 µm cap thickness
©DZ Reinstein 2016
Small Incision (and reserve incision)
• 2 mm is sufficient
• We use a supero-temporal incision (and second reserve)
• Others prefer single superior incision
• But difficult to then make a LASIK flap
Temporal Nasal Temporal Nasal
©DZ Reinstein 2016
• Reserve 2mm Small Incision
ReLEx SMILE: Lenticule Geometry
Temporal Nasal
• 6-7.5 mm Optical Zone
• 2 mm Small Incision
• 90° Lenticule Sidecut
• 8 mm Cap Diameter
• 135 µm cap thickness
©DZ Reinstein 2016
Lenticule Parameters: Minimum Thickness
• Minimum thickness can be reduced to 3 µm to maximize
tissue for refractive correction in high myopia
• Minimum thickness should be increased to make the
lenticule thicker in low myopia, usually 20-25 µm (the
other option is to increase the optical zone diameter)
High Myopia
Low Myopia
Comparison of Clinical Outcomes and Morphometric Correlation by Scanning
Electron (SEM) and Atomic Force Microscopy (AFM) Between Low and
High Energy SMILE.
David Sung Yong Kang1, Dan Reinstein2, Timothy Archer2, Jin Young Choi1, Byung Jin Ha1, Ji Yong Woo3, Hun Lee3, Tae Im Kim3
1. Eyereum Eye Clinic, Seoul, Korea. 2. London Vision Eye Clinic, Harley Street , London, UK. 2. Institute of Vision Science, Department of Ophthalmology, Yonsei Univ. College of Medicine, Seoul, Korea
D. Reinstein is a consultant to Carl Zeiss and no other author has a financial interest in any of the topics discussed.
20
19 19
18 18
17 17
18
15
16
17
18
19
20
100 105 110 115 120 130 140 150
Patient Allocation For Each Pulse Energy Group
Energy nJ
n Conventional Energy SMILE
(C-SMILE)
115 nJ
Low Energy SMILE
(L SMILE)
20 30
Scanning Electron Microscopy Each human lenticule was fixed with 2% glutaraldehyde/paraformaldehyde in 0.1 M phosphate buffered saline, pH 7.4, for 2 hours and washed three times for 30 minutes in 0.1 M PBS. CLs were postfixed for 2 hours with 1% OsO4
dissolved in 0.1 M PBS, dehydrated in a gradually ascending series of ethanol solutions (50-100 %), infiltrated with isoamyl acetate, and dried in a critical point dryer (HCP-2; Hitachi, Tokyo, Japan). Samples were coated with gold by
ion sputter (IB-3 Eiko, Japan) at 6 mA for 6 minutes, and then examined with a scanning electron microscope (FE SEM S-800; Hitachi, Tokyo, Japan) at an acceleration voltage of 10-20 kV and photographed at different magnifications
ranging from 100-10000×. Images were digitalized and stored as tagged image file format files in the microscope computer. SEM examinations were performed for anterior and posterior surfaces of the lenticules (AS-Len and PS-Len)
with each FSL energy group.
5 Diopter Spherical Equivalent Lenticules Obtained For Analysis; 3 From Each Energy
Atomic Force Microscopy (AFM) Single central area on the lenticule was imaged three times and averaged
Optical center with no forceps manipulation examined
Average Roughness (Ra)
RMS Roughness (Rq)
Ten-Point Mean
Height Roughness (Rz)
Clinical
Correlation
CONCLUSIONS
Better early postoperative clinical outcomes in L-SMILE group related to
less surface roughness of anterior and posterior lenticule surfaces.
Correlation between smooth optical surfaces and postoperative visual
acuity. Vinciguerra P, Azzolini M, Radice P, et al. A method for examining surface and interface irregularities after photorefractive keratectomy
and laser in situ keratomileusis: predictor of optical and functional outcomes. J Refract Surg 1998;14:S204-6.
Lower FSL energy creates smoother stromal lenticule interface
Higher FSL energy is associated with cavitations and OBL in the
anterior and peripheral cornea where strength is greatest
Using < 115 nJ energy contributes to fast visual recovery without
induction of HOAs in the very early post-operative period in SMILE.
Recovery technique for SMILE
upper interface
Glenn I Carp MBBCh, FC Ophth (SA)1
Dan Z Reinstein MD MA(Cantab) FRCSC DABO FRCOphth FEBO1,2,3,4
Timothy J Archer MA(Oxon) DipCompSci(Cantab)1
1. London Vision Clinic, London, UK
2. Columbia University Medical Center, New York, NY, USA
3. Centre Hospitalier National d’Ophtalmologie, (Pr. Laroche), Paris, France
4. Biomedical Science Research Institute, Ulster University, Coleraine, Northern Ireland
©DZ Reinstein 2016
Method: Routine SMILE Surgical Technique
• The routine surgical protocol was to:
– Open the supero-temporal incision
– Delineate the upper and lower lenticule planes
– Separate the upper followed by the lower interface
– Extract the lenticule
Upper Interface Dissected First
Incision
Lenticule
©DZ Reinstein 2016
• In some cases however:
– Open the supero-temporal incision
– Delineate the upper and lower lenticule planes
– Separate the upper followed by the lower interface
– When attempting separation, the instrument may slip into
the lower interface first…
Method: Recovery Technique
Lower Interface Dissected First
Incision
Lenticule
©DZ Reinstein 2016
If the lower interface was dissected
first, recovery can be achieved by:
Upper Interface Recovery Technique
1. Sinskey tip inserted
sideways into the incision
2. Tip rotated upwards to
engage the lenticule edge
3. Tip moved in a nasal
direction to release the
lenticule edge
4. Spatula then able to
dissect the upper interface
©DZ Reinstein 2016
Results
• This was a retrospective study of 629 consecutive SMILE
eyes of 369 patients, using the VisuMax femtosecond laser
• Upper interface dissected first:
– 555 eyes (305 patients [88%])
– Patients aged 21 to 64 years
– SEQ treated -5.41 D ± 2.43 D (-1.12 to -10.00 D)
– Programmed optical zone diameter 5.85 to 7.50 mm
– Cap thickness 100 to 145 µm
• Lower interface dissected first:
– 74 eyes (64 patients [12%])
– Patients aged 21 to 60 years
– SEQ treated -4.09 D ± 2.00 D (-1.00 to -10.00 D)
– Programmed optical zone diameter 6.00 to 7.50 mm
– Cap thickness 100 to 145 µm
©DZ Reinstein 2016
Results
Upper Interface: 1.25 Lower Interface: 1.29
Lower Interface: 1.14 Upper Interface: 1.16
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
20/10 20/12.5 20/16 20/20 20/25 20/32 20/40 20/63 20/80 20/100
Cu
mu
lati
ve %
Of
Eyes
Cumulative Snellen VA (20/x or better)
Uncorrected Distance Visual Acuity
Group 1
Group 3
Lower Group
Upper Group
P = 0.24
Upper First Group
Lower First Group
0 1 2 3 4 5
Mean Ease of Dissection
P = 0.07 Easy Hard
©DZ Reinstein 2016
Conclusion
• During the SMILE procedure, there is a possibility of
inferior plane dissection first
• This has been described previously as a ‘complication’
leading to sometimes aborting the procedure and
switching to PRK or LASIK
• It is possible and relatively easy to rescue the SMILE,
using a recovery technique utilising the sinskey
Retreatment options after SMILE
Glenn I Carp MBBCh, FC Ophth (SA)1
Dan Z Reinstein MD MA(Cantab) FRCSC DABO FRCOphth FEBO1,2,3,4
Timothy J Archer MA(Oxon) DipCompSci(Cantab)1
1. London Vision Clinic, London, UK
2. Columbia University Medical Center, New York, NY, USA
3. Centre Hospitalier National d’Ophtalmologie, (Pr. Laroche), Paris, France
4. Biomedical Science Research Institute, Ulster University, Coleraine, Northern Ireland
Retreatment Options After
SMILE
1. PRK
2. Sidecut Only
3. Circle
4. Thin Flap LASIK
5. Sub-cap lenticule extraction
(6. Intrastromal keratotomy)
Off-label
Retreatment Options After
SMILE
1. PRK
2. Sidecut Only
3. Circle
4. Thin Flap LASIK
5. Sub-cap lenticule extraction
(6. Intrastromal keratotomy)
Off-label
©DZ Reinstein 2016
SMILE Retreatment: PRK
• Brings the disadvantages of PRK
– Slow visual recovery
• 3/12 for the epithelium to remodel fully = Expect a hyperopic shift
– Pain management
– Haze
• ?MMC use, we prefer not to use it
• Can be used as long as final pachymetry >350 μm
Retreatment Options After
SMILE
1. PRK
2. Sidecut Only
3. Circle
4. Thin Flap LASIK
5. Sub-cap lenticule extraction
(6. Intrastromal keratotomy)
Off-label
©DZ Reinstein 2016
SMILE Retreatment: Sidecut
• Sidecut only converts the cap into a flap
• Easy to lift – equivalent to a regular femtosecond flap
• Flap diameter limited by original cap diameter – 8mm
– Not ideal for excimer ablation centration & transition zone
– Particularly difficult for hyperopic or topography-guided
retreatment
• Forced to have the flap as thick as the cap
©DZ Reinstein 2016
SMILE Retreatment: Sidecut Only
• 1o SMILE: Cap diameter 8 mm, cap thickness 120 μm
• Maximum cap thickness measured as 140 μm by
Artemis VHF digital ultrasound
• Not enough space for safe new flap (70-110 μm gap)
• Sidecut only programmed for 140 μm with 7.7 mm diam.
• TSA ablation performed for -1.00 -0.50 x 5 in 6 mm zone
Postop Cap i.e. incl epi changes
Original Cap i.e. with preop epi
116 μm
Postop Epithelium
140 μm 70 μm 110 μm
Retreatment Options After
SMILE
1. PRK
2. Sidecut Only
3. Circle
4. Thin Flap LASIK
5. Sub-cap lenticule extraction
(6. Intrastromal keratotomy)
Off-label
©DZ Reinstein 2016
SMILE Retreatment: Circle
• Circle option converts the cap into a flap with a larger
diameter
©DZ Reinstein 2016
SMILE Retreatment: Sidecut / Circle
• Sidecut and Junction cut easiest to lift
• Also flap bed was undisrupted with smooth transition
between circle interface and original cap interface
Good option for thin
cap SMILE cases
Retreatment Options After
SMILE
1. PRK
2. Sidecut Only
3. Circle
4. Thin Flap LASIK
5. Sub-cap lenticule extraction
(6. Intrastromal keratotomy)
Off-label
©DZ Reinstein 2016
SMILE Retreatment: Thin Flap LASIK
• Thin flap creates more superficial sidecut than circle
– Less biomechanical effect + greater residual corneal
strength
• Flap thickness chosen to avoid crossing interfaces
– Bowman's layer (cryptic buttonhole / gas breakthrough)
– SMILE lamellar interface – tricky dissection
©DZ Reinstein 2016
Epithelium
SMILE Retreatment: Thin Flap LASIK
+18 μm (4SD) = 118 μm
+18 μm (4SD) ≤80 μm
-18 μm (4SD) = 117 μm
Standard SMILE Protocol: • Use minimum 135 μm cap (55 epi + 80 Stroma)
• Retreatment as 100 μm flap LASIK
100 μm
135 μm
Posterior Cornea
©DZ Reinstein 2016
SMILE Retreatment: Thin Flap LASIK
Preop -3.75 -0.75 x 57
SMILE 130 μm cap
1 Yr Postop +1.00 -0.50 x 170
Postop Artemis:
Cap thickness minimum 120 μm
Epithelial thickness maximum 61 μm
90 μm flap LASIK retreatment
(achieves ±20 safety > 4SD)
©DZ Reinstein 2016
SMILE Retreatment: Thin Flap LASIK
Preop -3.75 -0.75 x 57
SMILE 130 μm cap
1 Yr Post +1.00 -0.50 x 170
LASIK 90 μm flap
1 Day Postop
©DZ Reinstein 2016
LASIK after SMILE
• Thin flap LASIK
• Ablation then has reached the SMILE interface
LASIK interface
SMILE interface
©DZ Reinstein 2016
SMILE then LASIK vs LASIK then LASIK
• LASIK retreatment introduces risk of epithelial ingrowth
• Primary LASIK (after SMILE) has very, very low risk of
epithelial ingrowth
• SMILE then LASIK actually safer than LASIK then LASIK
Retreatment Options After
SMILE
1. PRK
2. Sidecut Only
3. Circle
4. Thin Flap LASIK
5. Sub-cap lenticule extraction
(6. Intrastromal keratotomy)
Off-label
©DZ Reinstein 2016
• Use existing SMILE interface
• Only create the lower lenticule interface and sidecut
• Must ensure new lenticule sidecut meets existing cap
– Calculate accurate depth of new lenticule by measuring
epithelial thickening after primary procedure
– OCT / VHF digital ultrasound
Sub-cap-lenticule-extraction
©DZ Reinstein 2016
Sub-cap-lenticule-extraction
Post SMILE
20/63
-1.00 -1.00 x 5
Post SCLE
20/16
+0.50 -0.25 x 150
6.80mm 6.50mm
Retreatment Options After
SMILE
1. PRK
2. Sidecut Only
3. Circle
4. Thin Flap LASIK
5. Sub-cap lenticule extraction
(6. Intrastromal keratotomy)
Off-label
©DZ Reinstein 2016
Intrastromal Femto-Keratotomy Incisions
• A future option for very small refractions (where lenticule
would be too thin)
• Intrastromal femto-keratotomy incisions (don’t cross
Bowman’s) – same principal as RK
No loss of tissue
Anterior lamellae
left intact
Preoperative assessment, patient selection and
treatment planning for a SMILE patient
Glenn I Carp, MBBCh, FC Ophth (SA)1
Dan Z Reinstein MD MA(Cantab) FRCSC DABO FRCOphth FEBO1,2,3,4
1. London Vision Clinic, London, UK
2. Columbia University Medical Center, New York, USA
3. Centre Hospitalier National d’Ophtalmologie, (Pr. Laroche), Paris, France
4. Biomedical Science Research Institute, Ulster University, Coleraine, UK
Thank You
