Optic Coherence Tomography Evaluation of Intrastromal Ring Segments Implanted Manually and with a Femtosecond Laser

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Optic Coherence Tomography Evaluation of
Intrastromal Ring Segments Implanted Manually and
with a Femtosecond Laser

• Author Nicolas Cesário Pereira, M.D
• Co-Authors Mayana Freitas Lopes, M.D
• Camile Tonin, M.D.
• Leon Grupenmacher, M.D.
• Luciene Barbosa de
  Sousa, M.D.
• 
  
• Sorocaba Eye Bank
• Sorocaba-SP - Brazil
• The authors have no financial interest in the
  subject matter of this poster

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Introduction

• Intrastromal corneal ring segments have been
  implanted for 14 years with the manual
  tunnelization technique
• Induces central cornea aplanation
• Indications Keratoconus, MPD, Post-LASIK
  ectasia, post PK , post RK, post trauma
• Reversible, adjustable with fast visual
  reabilitation
• Femtosecond Laser can be used for tunnelization
• AS-OCT can be used to evaluate ring segments
  depth

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Purpose

• To evaluate intrastromal corneal ring segment
  depth with a high-speed corneal optical coherence
  tomography (OCT) system and to compare two
  techniques to implant the rings the manual
  technique and assisted by the femtosecond laser

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Setting

• Hospital Oftalmologico De Sorocaba, Sorocaba Eye
  Bank, Sorocaba, Brazil. All the surgeries, exams
  and this study were carried out at Sorocaba Eye
  Bank.

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Methods

• Retrospective review of 34 patients submitted to
  intrastromal corneal ring implantation at
  Sorocaba Eye Bank between 2006 and 2008.
  Prospective evaluation with OCT was performed at
  least 3 months after the procedure.
• Statistical analysis t test, block variable
  analysis and Pearson correlation analysis

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Methods

• Measurements with OCT-Visante
• KeraringR Triangular shape with base angle 0o
• Images with High Resolution Corneal Quad
• Measurements realized with Caliper
• 3 measurements
• M1 Anterior cornea surface to apice of
  implant
• M2 Base of implant to posterior cornea
  surface
• M3 Full thickness cornea measurement central
  
• to the implant

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Results

• 41 eyes 39 Keratoconus and 2 MPD
• 24 implanted manually 17 with FS
• FS Deeper and more regular
• Planed depth was closer achived with FS
• No statistical diference in clinical results
• Complications 3 extrusions (12,5) with manual
  technique no complications with FS
• In 2 patients with FS?OCT couldnt measure
  residual cornea, but the patients were OK.

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MANUAL FEMTOSECOND LASER P Value
AV pré c/c (Snellen) 0,3179 0,3779 0,1656
AV pré c/c (logMAR) 0,5950 0,7200 0,2287
AV pós c/c (Snellen) 0,7583 0,7382 0,6748
AV pós c/c (logMAR) 0,1333 0,1412 0,7830
EE pré -7,7708 -8,8125 0,3975
EE pós -3,8806 -3,8750 0,9954
Astigmatismo topo pré 6,1417 5,7588 0,6706
Astigmatismo topo pós 3,3217 4,1438 0,2459
Prof. planejada 0,4146 0,4000 0,2160
Prof pós ANP ANC AND 0,2794 0,2627 0,2522 0,3507 0,3507 0,3673 0,001 0,0001 lt0,0001
Prof pós ATP ATC ATD 0,2310 0,2371 0,2316 0,3580 0,3607 0,3729 lt0,0001 lt0,0001 lt0,0001
AV acuidade visual c/ccom correção EE
equivalente esférico Prof.profundidade ANP
anel nasal proximal ANCanel nasal central AND
anel nasal distal ATP anel temporal proximal
ATC anel temporal central ATD anel temporal
distal.
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MANUAL FS

• No relation with VA and depth of implants

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Results
Manual
Femtosecond Laser
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Conclusions

• OCT showed to be useful to evaluate the depth and
  regularity of intracorneal ring segments
• No difference in the clinical results
• Rings deeper and more regular with the FS
• This can lead to less extrusion rate and less
  complications with FS.

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THANK YOU!