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Dynamics of Big Bubble (BB) formation in DALK: in vitro studies
Author(s) -
ELALFY M,
FARAJ LANA,
SAID DG,
KATAMISH T,
DUA H
Publication year - 2014
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2014.4773.x
Subject(s) - clockwise , chemistry , anatomy , electron microscope , stroma , biophysics , biology , pathology , optics , medicine , physics , amplitude , immunohistochemistry
Purpose Dua’s layer (DL) has considerable relevance to DALK procedure and the hitherto clinically observed but unexplained formation of Types 1, 2 and mixed BB. In this study we explored the dynamics of the formation of different types of BB Methods 50 human sclerocorneal discs were injected with air under BSS and recorded. Videos were studied for leakage of air and formation of BB. Height and diameter of BB were measured. Specimens were subjected to electron microscopy and immunohistology for collagens & matricellular proteins. Age ranged from 3wk‐80yr Results Air injected in the cornea preferentially reached the limbus and moved circumferentially in a clockwise & anticlockwise direction as bands of 2‐3mm till they met, irrespective of direction of needle tip. The air then migrated centripetally to fill the stroma. Air leaked from the TM area at one or more points. Small bubbles formed in the centre and coalesced into a Type‐1BB. This rapidly expanded to attain a height of 5mm and a diameter of ≤9mm. The anterior stomal wall of Type‐1BB showed multiple 'holes' through which air leaked to lift DL. DL was impervious to air. Type‐2BB always started at the periphery. Distinct pores were seen in the peripheral stroma of DL. Most of these were located distal to attachment of DM and explained the leakage of air from TM. Some were located centrally to the attachment and explained formation of Type‐2BB. More than 80% of BB were Type‐1 Immunohistology did not offer an explanation for DL being impervious to air Conclusion DL is a distinct part of the surgical anatomy of the cornea. Identification of pores in DL periphery is novel and explains the formation of a Type‐2BB and the clinical observation of appearance of air in AC during DALK. Leakage is not through the TM