Hamish D. McKee, MB ChB
Luciane C. D. Irion, PhD, FRCPath
Fiona M. Carley, FRCOphth
Arun K. Brahma, MD, FRCOphth
Manchester Royal Eye Hospital, United Kingdom

• Penetrating Keratoplasty
– Femtosecond-assisted
• Anterior Lamellar Keratoplasty
– Deep Anterior Lamellar Keratoplasty (DALK)
– Anterior Lamellar Keratoplasty (ALK)
– Femtosecond-assisted
• Endothelial Keratoplasty
– Descemet’s Stripping Automated Endothelial
Keratoplasty (DSAEK)
– Descemet’s Membrane Endothelial Keratoplasty
(DMEK)
• Keratoprosthesis

8 week stage in utero endothelial cells secrete
DM continuously
A = banded DM prior to birth 3 micrometre
B = unbanded DM post-birth up to 7 micrometre

• 80-85% of structure of cornea
• Deeper layers more strictly organised than superficial layers
• Anterior cornea is more rigid
• Posterior cornea has poor rigidity
– During stromal swelling pressure directs against
DM
– Results in Descemet’s Folds

• Video
• Several techniques for anterior lamellar removal
• big bubble technique (Anwar)
– Surgically technically challenging
– Best method of ‘baring’ Descemet’s membrane
• Sugito and Kondo hydrodelamination technique
• Melles technique of manual dissection
• Rostron’s direct dissection method

• Less invasive the procedure, the better
• Avoid removing non-diseased, healthy tissue
• Remove only the part of the cornea that is dysfunctional
• Avoid open-sky situations

• Assumed that big-bubble DALK dissection plane is between stroma and Descemet membrane (DM)
Anwar M, Teichmann KD.
Big-bubble technique to bare Descemet's membrane in anterior lamellar keratoplasty.
J Cataract Refract Surg 2002;28:398-403.
• Study of 3 big-bubble posterior lamellae obtained during conversion to PK showed residual stroma on all 3
Jafarinasab MR, Rahmati-Kamel M, Kanavi MR, et al.
Dissection Plane in Deep Anterior Lamellar Keratoplasty Using the Big-Bubble Technique.
Cornea 2010 Feb 15.

• 2 types of big bubble seen clinically
• White-margin big-bubble
– As described in original paper
Anwar M, Teichmann KD.
Big-bubble technique to bare Descemet's membrane in anterior lamellar keratoplasty.
J Cataract Refract Surg 2002;28:398-403.
• Clear-margin big-bubble
– Appears like air-bubble in AC but not mobile
– Anwar suggested may represent intra-DM cleavage plane (AAO
Subspeciality Day November 10,
2007)
Edge of mobile air bubble in AC

• Donor corneas mounted on artificial anterior chamber
• Big-bubble dissection carried out
• Type of bubble noted
– White-margin
– Clear-margin
• Samples, formalin-fixed paraffin-embedded, evaluated with light microscopy using H&E and PAS stain

• 30 white-margin big-bubbles
– All showed residual stroma
Mean 7.0 μm (range 2.6 – 17.4)
• 2 clear-margin big-bubbles
– No residual stroma seen on
Descemet membrane
• Unable to determine on light microscopy if plane between
DM and stroma or intra-DM
Stroma (S), Descemet membrane (D), endothelium (E)

• The big bubble technique does NOT routinely bare DM
• The white margin seen during big-bubble DALK may indicate an intrastromal cleavage plane
• True baring of DM may only occur in the less commonly seen clear-margin big-bubble
• The disregulation of lamellar fibres within the stroma of keratoconus may explain why the big bubble is a surgically difficult procedure with relatively low success
• It is important to note the type of big-bubble obtained clinically for histological or clinical research on bigbubble DALK