Dye-based identification of the orientation of tissue for Descemet stripping automated endothelial keratoplasty: A laboratory-based study

Abstract

Purpose: To describe the features enabling the identification of the orientation of Descemet stripping automated endothelial keratoplasty (DSAEK) lenticule with the assistance of vital dyes.

Methods: This is a blinded experimental lab-based study, including 30 microkeratome prepared precut DSAEK lenticules. The lenticules were divided into control and study arms which included 10 unstained and 20 stained lenticules, respectively. In the study arm, vital dyes like trypan blue (TB), brilliant blue (BB), indocyanine green (ICG) and fluorescein stain (FS) were used to stain 5 lenticules each. They were examined by experienced (group 1) and novice surgeons (group 2) to identify the correct orientation of the lenticule. The results were tabulated and analyzed.

Results: Of the 30 lenticules examined, the average of total scores obtained by each observer was higher (78%) in group 1 as compared to group 2 (65.3%) which was statistically significant (P < 0.005). In group 1, the accuracy of identifying the correct orientation of unstained lenticules was 70% which improved to 82% on staining. The accuracy in group 2 was 58% with unstained lenticules which improved to 69% on staining. Within the study arm, irrespective of surgical experience, the accuracy was highest with BB (86%), followed by TB (82%), ICG (72%) and FS (62%).

Conclusion: This study found that the accuracy of identifying the orientation of DSAEK lenticules increased with experience and with the assistance of staining using vital dyes. This accuracy improved with blue dyes like brilliant blue and trypan blue, irrespective of the level of experience.

Keywords: Descemet stripping endothelial keratoplasty; dye based identification of lenticule orientation; endothelial transplant; loss of orientation of lenticule.

Figure 1

The scores obtained in the overall group and in study and control arms: This bar diagram shows the scores in the study arm, control arm and overall group among experienced (group 1) and novice surgeons (group 2). The scores obtained by observers in group 1 were higher than group two in both study and control groups

Figure 2

The scores obtained with respect to the vital dyes used for staining: The bar diagram shows the scores of group 1 (experienced surgeons) and 2 (novice surgeons) with respect to the various stains used in the study. The scores in group 2 improved on staining with the blue dyes like brilliant blue (BB) and tryphan blue (TB) as compared to Indocyanine green (ICG) and Fluorescein stain (FS)

Figure 3

The morphological characteristics of stromal and endothelial surface of the lenticule: The images show stromal and endothelial surfaces of a DSAEK lenticule stained with brilliant blue. The stromal side up (a) shows a characteristic matted look with granular appearance of the surface and stromal fibers (white arrow) being discernible. The endothelial side (b), has a smooth and glistening surface with more prominent Desemet’s membrane folds (black arrow) and lack of granularity or discernable fibres

Figure 4

Appearance of DSAEK lenticules when stained with vital dyes: The image is a collage of the lenticules stained with Brilliant blue (a and b), Trypan blue (c and d), Indocyanine (e and f) and Fluorescein stain (g and h). The top row shows the stromal surface and bottom row shows the endothelial surface of the lenticules. The morphological features like stromal fibres, granularity and glossy endothelial surface appear more enhanced on staining with brilliant blue