• Pre-‐Descemet's Endothelial Keratoplasty (PDEK) is gaining momentum as an effec<ve alterna<ve to current endothelial keratoplasty techniques. • Eye banks should become proficient at preparing PDEK graCs effec<vely. • This study evaluated factors influencing successful PDEK graC prepara<on and trialed novel strategies quan<fying PDEK graC thickness and endothelial cell loss (ECL), as alterna<ves to specular microscopy post-‐prepara<on.
Ashiyana Nariani, MD, MPH,1 Dhivya Ashok Kumar MD,2 Amar Agarwal M.S., FRCS, F.R.C.Ophth,2 Isaac Perry MBA, CEBT,3 Mike Tramber MBA, CEBT,3 Anthony Kuo MD,1 Melissa Daluvoy MD,1 Alan Carlson MD,1 Terry Kim MD1
1Duke University Eye Center, Durham, North Carolina, U.S.A. 2Dr. Agarwal’s Eye Hospital, Chennai, India
3Miracles In Sight Eye Bank, Wwinston-‐Salem, North Carolina [email protected]
Introduc<on & Purpose
• With the innova<on of PDEK, eye banks will need to learn how to prepare PDEK graCs effec<vely and predictably in order minimize wastage of corneal donor <ssue and ECL. • Descemet’s membrane micro-‐perfora<ons and a bubble burst during BSS expansion were the primary e<ologies for unsuccessful a^empts at PDEK graC prepara<on. • An increased number of air injec<ons a^empts decreased the likelihood of type 1 or 2 bubble forma<on. • Further inves<ga<on is needed to strategize faster and gentler modifica<ons in <ssue handling in order to op<mize PDEK graC prepara<on.
• An ex-‐vivo inves<ga<on of 15 corneas was trialed for PDEK graC prepara<on at the Miracles In Sight Eye Bank (Figure 1). • Op<cal coherence tomography (OCT) imaging was used to evaluate interface, uniformity and graC thickness (Figure 2). • The graC endothelial surfaces were stained with trypan blue, underwent digital photography and ECL quan<fied using Fiji imaging soCware, both pre-‐ and post-‐ graC processing (Figure 2).
The authors have no financial interest in the subject ma^er of this presenta<on. Figure 2. Post-‐graC prepara<on analysis with OCT and FIJI soCware.
Figure 3. Outcomes of GraC Prepara<on
Figure 1. PDEK GraC Prepara<on Technique. a. A 30-‐gauge needle, bevel up, was directed from the sclera, 2.00 – 3.75 mm from the limbus, into stroma. Bursts of air were injected un<l a type I bubble formed. b. Air in the bubble was then displaced with balanced salt solu<on (via injec<on into the bubble), which also provided controlled expansion of the bubble. c. Once the desired diameter was achieved, the bubble was collapsed by drawing the fluid out of the interface. The graC was stained with trypan. The area where the bubble had formated was then trephined and peeled.
• Of the 15 corneas , 9 corneas achieved a type 1 bubble, 2 achieved a type 2 bubble, and 4 had Descemet's membrane perfora<ons. Of the 9 with a type 1 bubble ini<ally, 2 subsequently perforated during BSS expansion, as did both type 2 bubbles (Figure 3). • For the 7 (46.7%) successfully prepared PDEK graCs, all were created on first air injec<on a^empt, average bubble diameter was 8.11 millimeters (mm) and average needle bevel posi<on was 2.82 mm from the limbus (Table 2). • Mean OCT graC thickness was 37.5 micrometers (µm), with a standard devia<on of 1.87 µm. • Mean ECL pre-‐ and post-‐ graC prepara<on were 8.26% and 24.8%, respec<vely.
Donors
Type I bubble
Success Late Descemet perfora<on
Type II bubble Descemet perfora<on
Table 1. Donor Age and Needle Posi<on During GraC Prepara<on
Eye Bank Donor Gra; Prepara>on for Pre-‐Descemet’s Endothelial Keratoplasty Abstract Number: 1222 -‐ D0170
Characteris>c Mean Standard Devia>on Range
Needle bevel stromal posi<on (distance from limbus, mm)
2.82 mm 0.22 2.50 -‐ 3.00
Type I bubble diameter (mm) 8.11 mm 0.23 7.75 – 8.50 Final GraC Diameter (mm) 7.57 mm 0.11 7.50 – 7.75 Pre-‐processing endothelial cell loss % 8.26% 7.07 0.00 – 21.30
Post-‐processing endothelial cell loss % 24.80% 6.19 15.60 – 34.00
GraC thickness by OCT (microns) 37.57 microns 1.59 35.00 – 40.00
1. Agarwal A, Dua HS, Narang P, Kumar DA, Agarwal A, Jacob S, Agarwal A, Gupta A. Pre-‐Descemet’s endothelial keratoplasty (PDEK). Br J Ophthalmol. 2014 Sep;98(9):1181–5.
2. Altaan SL, Gupta A, Sidney LE, Elalfy MS, Agarwal A, Dua HS. Endothelial cell loss following <ssue harves<ng by pneumodissec<on for endothelial keratoplasty: an ex vivo study. Br J Ophthalmol. 2015 May;99(5):710–3.
3. Macsai MS, Nariani A, Reed C. Eye banking: What the eye bank can do for you. In: Jeng BH, ed. Advances in Medical and Surgical Cornea: From Diagnosis to Procedure. Berlin, Germany: Springer. 2015; 133-‐143.
Results
Key References
Financial Disclosures
a. b. c. d.
Conclusions
Methods
Characteris>c Successful Unsuccessful Overall P-‐value
Donor Age (years)
Mean 60.71 56.50 58.47 0.37
Standard Devia0on 4.53 10.44 8.49
Range 54 -‐ 67 32 -‐ 68 32 -‐ 68
Needle bevel stromal posi>on (distance from limbus, mm)
Mean 2.82 2.83 2.83 0.96
Standard Devia0on 0.22 0.48 0.44
Range 2.50 – 3.00 2.00 – 3.75 2.00 – 3.75
Results (Con<nued) Table 2. Successful PDEK GraC Characteris<cs
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