Доклад на Пятой научно-практической конференции с международным участием «Основные тенденции в современной офтальмологии», организованной клиникой профессора Эскиной Э.Н. «Сфера», совместно с кафедрой офтальмологии ФГБОУ ДПО ИПК ФМБА России —→ http://www.sfe.ru/information/ophthalmology-news/conference2015.html
7. • Tissue removal tecnique is repeatable and accurate
- compared with the excimer laser is not affected by ± stromal
dehydration, laser fluence , laser impact geometry
(center vs. periphery of the cornea)
- equal procedure time (it does not depends on the refractive defect)
- the accuracy of the cutting is related only to the laser Fs precision
(± 4.4 mM) * and not to external factors
ReLex SMILE: advantages
*
9. Effect of Flap Thickness and Shape on
Corneal Biomechanics
80 µ
140 µ
160 µ
180 µ
14% 25%
29%
33%
Loss of strength
Flap depth
Slide courtesy of John Marshall, Ph.D.
10. Effect of Flap Thickness and Shape on
Corneal Biomechanics
* John Marshall, Ph.D.
“Weak” Cornea
6 mm
“Strong” Cornea
8-12 mm
“Strong” Cornea
160 µm
“Weak” Cornea
340 µm
SMILE
PRK/LASIK
11. Corneal Biomechanics is preserved
ReLex SMILE: advantages
• Absence of a flap
• Anterior stromal lamellae are intact
• Cutting of the lenticule is especially in the weak cornea
* Postop Tensile Strength: SMILE > 10% Vs PRK
SMILE > 25% Vs Lasik
*
! Possibility of treating medium-high myopia (EqSf -10D; max -10D sf; max -5D Cyl) !
12. - Less induction of spherical aberrations Vs PRK/Lasik
- Best optical quality
At the same refractive defect it is possible to increase the
optical zone while not interfering significantly on corneal
biomechanics !!
ReLex SMILE: advantages
13. Example
Reinstein DZ, Current status of SMILE. Cataract & Refractive Surgery Today 2014 Sept; 2-4*
Pachimetry 588 µm; defect -10D sf;
SMILE
• O.Z. 7 mm !!
• lenticule 203 µm
•Stromal residual250 µm
• cap 135 µm
• total stroma335 µm
(50 µm epithelium)
• post-op tensile strength 58% !!
• AbSph induced 0.15 µm !!
LASIK (MEL 80)
• O.Z. 6 mm !!
• Flap 100 µm
•Stromal residual 298 µm
• post-op tensile strength 44% !!
• AbSph induced 0.75 µm !!
*
14. ReLex SMILE: advantages
Less postoperative dry eye
• It is crucial to preserve the basal and sub-baseline corneal
innervation structure to reduce the risk of Dry-Eye
• In PRK and LASIK whole anterior nerve plexus is completely
cut off / ablated
The ability to leave intact the structure significantly reduces the
risk of dry eye
- Corneal lenticule is deeper -
15. ReLex SMILE: advantages
• Corneal sensitivity restored more quickly than PRK / LASIK
(3 months Vs 6-12 months)
17. ReLex SMILE: disadvantages
• Surgical technique more difficult
• Long learning curve
• Possibility of treatment of residual defects only by PRK
• Difficulty seeing plans detachment plans (top / bottom)
• Extreme difficulty in delamination of the lower floor
before running the upper
• Irregular astigmatisms for residual pieces of lenticule in
dissection area.
23. 80 eyes are enrolled in the study
INCLUSION CRITERIA:
Age >18 years old
astigmatism 0.00/5.00
spherical equivalent -0.75/-10.00
corrected distance visual acuity(CDVA) of 20/40 or better (>0.3 logMAR)
a minimum calculated postoperative residual stromal bed of 250 μm
EXCLUSION CRITERIA:
keratoconus
glaucoma
radial keratotomy
corneal scarring
retinal degenerative disease
24. All patients underwent a preoperative evaluation including :
Correct and uncorrect visual acuity
Slit lamp examination (anterior and fundus)
corneal topography (Sirius ,CSO)
OCT pachymetry(Optovue)
pupillometry
aberrometry
endothelial cells dencity
tearing test
tonometry
refraction examination in cycloplegia
Follow up visit :
1 week and 1, 3 and 6 monts after the treatment
25. Therapy
• a topical antibiotic
2 days before surgery and 1 week after surgery
• a topical steroid
for 2 weeks after surgery
• hyaluronic acid drops
for 4 months after surgery
26. EYES 80
SEX M:F 32 : 48
AGE 33 ± 11
Mean corneal power D 44,10 ± 1,54
UDVA logmar 1,62 ± 0,22
CDVA logmar -0,049 ± 0,052
IOP mmHg 15,47 ± 2,42
SPHERE diopter -6,02 ± 1,90
CYLINDER diopter -1,02 ± 0,7
SPHERICAL EQUIVALENCE diopter -5,95 ± 1,01
CCT microns 528 ± 31,3
Expected residual corneal bed 290,1 ± 26,0
Preoperative data
28. The recovery of visual acuity is related to
the excellent surface of cut obtainable with the femtolaser 500 Khz
in both upper and lower lenticule surface.
Regular and homogeneous cut surfaces seems to fit better
postoperative visual acuity
-0.12
-0.1
-0.08
-0.06
-0.04
-0.02
0
1 w 1m 3m 6m
logmar
Follow up
ucva logmar
cdva logmar
29. In our series the residual spherical equivalent
was very low and stable over time
Comparison of spherical equivalent refraction stability
31. Pachimetric postoperative residual value
remained stable during the 6 months of observation
the thickness of the extract corneal lenticule,
(calculated as difference between pre and
postoperative OCT-pachimetric value)
at 6 months was 101 ± 21 microns
32. No visually threatening complications
No patient presented in the postoperative
ocular surface diseases or alteration of the tear film
No cases of epithelial ingrowth,
severe diffuse lamellar keratitis or keratoectasia
33. Results
In the postoperative follow up
no patient presented any complications related surgical procedure
and the follow up was regular in all patients
Retreatment was not necessary
34. Conclusions
• SMILE is an effective, safe and repeatable refractive
procedure
• Ability to correct high myopic values
• Corneal biomechanics almost preserved
• Reduced risk of Dry-Eye
• Rapid recovery of corneal sensitivity