Confocal scan study of corneal grafts following Descemet-on versus Descemet-off deep anterior lamellar keratoplasty Zare M, Feizi S, Rezaie M, Hoseini.

Confocal scan study of corneal graftsfollowing Descemet-on versus Descemet-off

deep anterior lamellar keratoplasty

Zare M, Feizi S, Rezaie M, Hoseini B. MDs

Hasani H, MD

Shahid Beheshti University of Medical Sciences

WCC VII -2015

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The authors have no financial interests or relationships to disclose.

Financial Disclosure

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To compare confocal and biomechanical features of grafts following deep anterior lamellar keratoplasty (DALK) using a donor without Descemet’s membrane (DM) versus a full-thickness donor with intact DM.

Purpose

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Design: non-randomized cross-sectional comparative study.

45 eyes with keratoconus who underwent DALK using the big-bubble technique were enrolled.

Of which, 27 received a donor without DM (group1) while in 18 eyes; a full-thickness donor with an intact DM was used (group 2).

A group of normal eyes (n=28, group 3) served as controls.

Methods

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Confocal microscopy was used to determine cellular profiles of grafts and the features of donor-recipient interface.

Additionally, corneal hysteresis (CH) and corneal resistance factor (CRF) were measured.

The results were compared between the study groups using ANOVA test.

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Mean follow-up duration was 20.2±8.6 months and 29.6±17.0 months in groups 1 and 2, respectively (P=0.13).

CH was 9.82±1.93 mmHg in group 1, 9.51±1.22 mmHg in group 2 and 9.84±1.59 mmHg in group 3 (P=0.76).

Results

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CRF was 9.57±1.87 mmHg, 9.04±1.55 mmHg and 9.89±1.73 mmHg, respectively (P=0.24).

Confocal scan demonstrated that the keratocyte profiles and distribution were more similar to normal corneas in group 2.

Additionally, significantly more severe interface haziness was observed when donor DM was retained.

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The density and distribution of keratocytes in group 2 look like the normal group. But, group 1 shows reduction in keratocyte density in anterior and posterior stroma.

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Donor-recipient

interface.: Confocal

scan illustrates sheets of

hyper reflective and

amorphous extracellular

deposits together with

high-contrast micro-dots

at the interface. These

deposits are more

prominent in group 2

compared to group 1.

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Donor features Group 1 Group 2 P-value

Age (years) 36.5±16.4 29.4±7.9 0.29

Graft rating

Excellent

Very good

Good

Fair

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10

5

4

2

8

6

2

0.51

Endothelial cell density

(cells/mm2)2849.4±648.5 2685.3±507.3 0.43

Death-to-preservation time

(hours)10.8±5.5 10.7±7.8 1.0

Mean storage time (days) 3.4±4.1 3.7±1.2 0.89

Table 1: Donor data in DALK groups

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Table 2: Scotopic and photopic contrast sensitivity (dB) in the DALK groups

Spatial frequency Group 1 Group 2 P-value

1 cpdScotopic 17.39±1.53 14.75±3.77 0.04

Photopic 17.30±1.30 14.83±3.56 0.02

2 cpdScotopic 18.52±3.09 15.92±4.87 0.11

Photopic 18.78±2.66 14.92±5.74 0.04

3 cpdScotopic 18.22±4.31 16.33±5.50 0.27

Photopic 18.74±4.71 15.42±5.18 0.06

6 cpdScotopic 15.61±4.94 13.50±5.60 0.26

Photopic 15.78±5.21 11.83±5.39 0.04

12 cpdScotopic 9.74±5.29 7.83±4.99 0.31

Photopic 10.61±5.37 7.25±4.73 0.08

20 cpdScotopic 5.35±3.46 4.58±3.66 0.55

Photopic 6.30±4.02 5.0±2.92 0.33

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Table 3: Anterior, middle, and posterior stromal keratocyte density, and endothelial cell density and morphology in the three study groups

Parameters Group 1 Group 2 Group 3 P (ANOVA) P1 P2 P3

Keratocyte

density

(cells/mm2)

Anterior 499.5±137.6 635±198.8 737±65.8 <0.001 <0.001 0.05 0.01

Middle 548.7±101.2 568.2±78.9 604.4±54.6 0.04 0.04 0.47 1.0

Posterior 306.1±99.0 579.7±95.3 602.4±46.4 <0.001 <0.001 1.0 <0.001

Endothelial cell density

(cells/mm2)2621.2±388.2 2333.1±450.9 2987.2±327.7 <0.001 0.002 <0.001 0.06

Hexagonality (%) 53.6±7.8 57.3±8.3 55.3±7.8 0.33 1.0 1.0 0.42

Polymegethism (%) 31.5±5.2 31.2±7.5 34.0±5.6 0.20 0.36 0.41 1.0

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Two techniques of donor preparation for DALK provide comparable results in terms of graft biomechanics.

However, graft cellular profiles and healing response at the donor-recipient interface can profoundly be affected depending on whether donor DM is removed or retained.

Conclusion