Authors:
Jaroslav Madunicky, MD
Katerina Buusova Smeckova, MD, MBA
Col. Assoc.Prof. Jiri Pasta, MD, PhD.
Iveta Nemcova, MD, PhD.
Eva Vyplasilova , MD
Kristina Hakucova, MD
Department of Ophthalmology of the First Faculty of Medicine
of Charles University and Central Military Hospital, Prague
None of the authors has a financial interest on the presented data.
Purpose
• To evaluate the change of change in the refractive
error, BCVA, pachymetry and corneal topography of
50 patients, who underwent in our Clinic since 2009
uni- or bilateral implantation of the keraring(s) using
the femtosecond laser iFS 150 following Madunicky
Formula.
• To statistically evaluate effect based on the degree of
keratoconus (I-IV) and max. keratometry localization.
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Setting / Venue
N° of patients
N°of eyes
Mean age
Preop UCVA
Preop BCVA
Preop refractive error
Preop autorefractometry
Pachymetry
Max. keratometry
Degree of keratoconus
according to Pentacam
Type of ectasia
Total
50
Male
Female
44
6
53
33 (20 ; 55)
0,26(0,05 ; 0,5)
0,63(0,2 ; 1,0)
-1,35()-3,76
[0.00()-1,25; -4,5()-6,25]
-4,57()-5,78
[-10,75;+2,50 () -1;-9,75]]
459,52 [426 ; 500]
58,21 [48,1 ; 66,7]
1-2
2
3
3-4
0,5%
9,5%
10%
80%
1
2
3
4
13%
41%
28%
18%
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Methods
 Prospective, unmasked, non-randomized study of 50




patients with keratoconus (53 eyes), grade 2 to 3-4, who
underwent the implantation of SI-5 Keraring/s.
Degree of keratoconus and type of ectasia according to the
localization of maximal keratometric readings were
determined, other pathologies were described.
Preoperatively and 1, 6 and 12 months postoperatively
UCVA, BCVA, autorefractometry, pachymetry
measurements and keratometry readings were obtained.
Implantation of keraring/s was performed in local
anesthesia implanted into the tunnel created by Intralase
iFS 150 set according to the Madunicky Formula. No
peroperative complications were reported.
Ring was selected according to the currently valid
nomogram and preoperative examination of the patient.
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MADUNICKY´S FORMULA
DF = (0.8 TP x AC) - (SC x RC)
DF = (0.8 TP x 0.92) - (-20 x 0.5/0.1)
DF: Depth of the femtotunnel (µm)
TP: Thinnest pachymetry (µm)
AP: Applanation coefficient
SC: Safety coefficient (µm)
RC: Ring coefficient
Results I.
Mean UCVA-1M,6M and 12
M after implantation
0.5
0.44
UCVA 12 Months after Procedure
0.46
11%
0.45
0.4
0.34
11%
0.35
0.3
0.26
0.25
0.2
0.15
78%
0.1
0.05
0
prior
surgery
1M
postop
6M
postop
12M
postop
Worse
Unchanged
Improved
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Results II: Evaluation of
UCVA
&
• -1,34Dsf/-3,76Dcyl=0,63
•0,25 +/- 0,02 [0,05;0,5]
•0,34 +/- 0,03 [0,1;0,7]
BCVA
before
surgery
• -1,81Dsf/-1,82Dcyl=0,63
1M after
• 0,44 +/- 0,05 [0,2;0,8]
• -2,50Dsf/-2,4Dcyl=0,63
6M after
• 0,41 +/- 0,07 [0,2;0,9]
• -1,3Dsf/-2,2Dcyl=0,62
12M after
Improved by 1,61D of SE
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Results III.
Change in pachymetry
Change in K max. and grade
58.2
475
60.0
50.9
Prior surgery
12M after
470
μm
40.0
465
20.0
2.9 2.6
460
0.0
455
450
Pachymetry
Kmax
Prior
460
1M
after
469
6M
after
471
12M
after
471
Degree of
keratoconus
Prior surgery
58,2 [48,1 ; 66,7]
2,9 [1,5 ; 3,5]
12M after
50,9 [44,8 ; 52,8]
2,6
[1 ; 3,5]
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Results IV.: Evaluation of
Autorefractometry & Pachymetry
• 459,52
• -4,57Dsf/-5,78Dcyl
• -2,42Dsf/-2,87Dcyl
before
surgery
[426;500] um
• 469,14[423;583]
um
1M after
• -3,45Dsf/-2,75Dcyl
• 471,14[438;527] um
6M after
• -2,39Dsf/-2,17Dcyl
• 477,77[453;529] um
12M after
Improved by 5,79 D of SE
Improved by 18,25 [3;31]
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Results V.
 In the interval of 1 year of the implantation 2/3 of patients
have improved both their UCVA and BCVA. Statistically
are the most succesfull group grade II and III. In this group
there is no worsening of the BCVA, in 1/3 it only remained
unchanged. Vision of 11% of patients in the group grade
III-IV got worse during this period.
 In a group grade II-III is more expressive the change of the
SE, as the flattening of the extasia.
Complications
 Ring dislocation
 Optical phenomenon
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Comparison of possible keratoconus
treatments
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Conclusion
 Keraring implantation with the iFS 150 following Madunicky Formula
and up-to-date nomograms, when performed by an experienced
surgeon, seems to be a safe and full-valued treatment, which helps
patients on their way to stabilize the disease and to postpone the need
to perform a perforative keratoplasty.
 The effect of implantation is quite individual and it depends on the
degree of disease, progression / stability of the disease and the location
of the ectasia in the cornea (depth, symetry).
 On our clinic we perform the implantation of the intrastromal
segments only with the femtosecond laser set according to the
Madunicky Formula. The results seem to be very perspective. The
procedure itself is less stressful for both patient and surgeon and we
have not reported so far any case of extrusion or perforation.
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