DSAEK GRAFTS WITH PARALLEL FACES : IS THE FUTURE? Luca Avoni IV ivis suite user meeting Innsbruck, 6 July 2013

Grafts with parallel faces Purpose:  avoid hyperopic shifts post DSAEK  obtain a thin graft with a uniform thickness from one side to the other in order to reduce the incidence of post- operative detachment

Retrospective observational study 15 donor corneas not suitable for transplantation, for morphological abnormalities or donor is not suitable for medical history, according to the following protocol : 1. Corneal pachymetry with corneal optical tomography 2. Setting pachymetry to a constant thickness of 550 um with excimer laser 3. Acquisition of corneal pachymetry 4. Cut of stromal flap with microkeratome for a thickness of 400 um 5. Acquisition of corneal pachymetry 6. Histological analysis of the cross section of stromal and endothelial flap

Retrospective observational study: Instruments 1. Optical tomography 2. Software for customized ablation. 3. Excimer laser. 4. Microkeratome 5. Ophthalmic microscope

Retrospective observational study Software for the regularization of the corneal stroma to a desired thickness by a customized ablation with excimer laser

OBJECTIVES:  Realization of stromal lenticule with uniform thickness of 550 μ by a customized ablation with excimer laser  Realization of endothelial lenticule with uniform thickness of 150 µ  To evaluate the safety and effectiveness of this procedure

Step 1 Evaluation of the cornea by microscope according to the traditional criteria of the EYE Bank (cell density, margins, morphology and mortality) Morphological evaluation of corneal endothelium Density Cell/mm2 N =13 Mortality % N =13 Mean σ % 0.07 Interval 1000 ÷19000÷30 Morphological evaluation of corneal endothelium Margins N=13 Homogenous CI 95% 3/ % ( ) Partially Homogenous CI 95% 9/ % ( ) Irregular CI 95% 1/ % ( ) Morphological evaluation of corneal endothelium Morphology N=13 Polymorphism CI 95% 7/ % ( ) Moderate Polymorphism CI 95% 6/ % ( ) ITER

Step 2 Optical Corneal tomography with and study of the pachymetry map with high repeatability ITER Optical pachimetry examination of the cornea Min Pachimetry [ µ ] N=13 Max Pachimetry [ µ ] N=13 Mean σ , Interval 568 ÷ ÷ 767

STEP 3 Set up a Customized ablation to regularize the stroma to a constant residual thickness of 550 microns ITER

STEP 4 Customized ablation with laser in order to obtain a regular stroma lenticule of 550 microns thickness ITER

STEP 5 Optical corneal tomography to assess the pachymetry ITER Optical Pachimetry after the laser regularization of the Cornea Pachimetry [ µ ] N=13 Target Left pointCenter pointRight point Mean σ CI 95% ,67 573,46 7, ±25 µ

STEP 6 Cut of the stromal flap with a microkeratome 400 micron-head to obtain a endothelial lenticule of 150 micron thickness. ITER

STEP 7 Pachymetry of endothelial lenticule. Thickness of stromal lenticule is obtain by the difference between the pre-cut pachymetry and post-ablation pachymetry. ITER Optical Pachimetry after the 400 microns cut with microcheratomy of the endothelium lenticule Pachimetry[ µ ] N=13 Target 150 ±50 µ Left pointCenter pointRight point Mean σ CI 95% Pachimetry of stromal lenticule after the 400 microns cut (Difference between optical corneal pachimetry and optical endothelium optical pachimetry ) Pachimetry [ µ ] N=13 Target Left pointCenter pointRight point Mean – = = 405, , = 417, ± 25 µ

Morphological evaluation of corneal endothelium Density [Cell/mm2] N =13 Mortality [ % ] N =13 Mean σ % 0.48 Delta (Mean pre – Mean post) Reduction % Increase % Target Reduction < 10%Not Defined Morphological evaluation of corneal endothelium Morphology N=13 Delta (Mean pre – Mean post) Polymorphic CI 95% 7/ % ( ) No change Moderate Polymorphic CI 95% 6/ % ( ) No change Morphological evaluation of corneal endothelium Margins N=13 Delta (Mean pre – Mean post) Homogenous CI 95% 3/ % ( ) No change Partially Homogenous CI 95% 9/ % ( ) No change Irregular CI 95% 1/ % ( ) No change ITER STEP 8 Evaluation of the endothelial lenticule by microscope according to the traditional criteria of the EYE Bank (cell density, margins, morphology and mortality)

ITER STEP 9 Histological evaluation of endothelial lenticule (thickness and morphology) and the stromal lenticule (thickness and morphology.) Histological Thickness evaluated at 4 months after procedure execution Endothelium lenticule [ µ ] N=13 Stromal lenticule [ µ ] N=13 Measured value Target Measured value Target Left pointCenter pointRight point 150 ±50 µ Left point Center point Right point 400 ±25 µ Mean ,7 522,7540,1 σ CI 95% , ,

CONCLUSIONS This clinical study showed that the procedure of regularization of the cornea thickness with the excimer laser IRES is effective and safe as shown in the following endpoints.

Fate clic per modificare il formato del testo della struttura  Secondo livello struttura Terzo livello struttura  Quarto livello struttura Quinto livello struttura Sesto livello struttura Settimo livello struttura Ottavo livello struttura  Nono livello strutturaFare clic per modificare stili del testo dello schema Secondo livello  Terzo livello Quarto livello  Quinto livello Histological evaluation  Paraffin embedding  Staining with hematoxylin and eosin  Scanner digital slides  Measurement with morphometro

Endothelial and stromal lenticules

CONCLUSIONS Endpoint 1 –Stromal regularization: The pachymetry after the customized ablation of the stromal lenticule has shown that the average thickness of 550 ± 25 micron has been achieved successfully

CONCLUSIONS Endpoint 2 – Endothelial lenticule: The pachymetry after the microkeratome cut of the endothelial lenticule has shown that the average thickness of 150 ± 50 micron has been achieved successfully In addition to optical pachymetry, histological analysis, performed at the Pathology Department of Ospedale Maggiore-Bologna in October 2012, provided a further confirmation of the results.

CONCLUSIONS Endpoint 3 – Stromal Lenticule: The difference between the pachymetry performed before and after the customized ablation of the stromal lenticule has shown that the average thickness of 400 ± 50 micron has been achieved successfully. The histological analysis has shown in this last case a stromal lenticule of 508,7 μm thickness of the left side, 522,7 μm of the center and 540,1 μm of the right side. Probably, this inconsistency is due to the delay of more than four months from the date of execution of the procedure and the date of execution of the histological analysis.

Thank you