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Anterior Segment Cornea
Descemet’s membrane that could easily detach from stroma.
Case reports of a triple procedure in Fuchs’ dystrophy patients
Central anterior cap thickness of pre-cut grafts were compared and involving anterior chamber IOL implantation have been successful in
found to be dependent on depth plate, eye bank and pre-dissection patients with an anterior chamber depth >3mm.
thickness. As with laser in situ keratomileusis (LASIK) flap thickness,
thicker corneas led to deeper cuts.
Thickness and curvature New Surgeons
coefficients derived from the graft thickness profile are known to alter New surgeons are encouraged to start performing DSAEK on patients
who have an intact iris–lens diaphragm in order to prevent donor
There is a relatively steep learning curve to DSEK/DSAEK;
Femtosecond laser is another modality used to cut DSAEK grafts. The however, a recent study comparing surgical results from attendings
laser performed deep posterior stromal ablations to achieve accurate, and fellows showed that vision, endothelial loss and complications
intended measurements of corneal thickness and diameter of corneal were not statistically different at six-month follow-up.
buttons in an ex vivo study.
Femtosecond-cut grafts are purported to
produce minimal change in refractive astigmatism and cause a mild Comparisons
hyperopic shift in refraction.
Comparisons between DSAEK and other types of keratoplasty have
been favourable. In comparing PK and DSAEK, BCVA ≥20/40 (0.3)
Surgical Technique and Donor Positioning was 70–80% in DSAEK and 25% in PK patients, and ≥20/25 (0.1) in
In DSAEK, the diseased endothelium is replaced by a graft consisting 6–20% in DSAEK and 0% in PK patients at one-year follow-up.
of a thin layer of posterior stroma, Descemet’s membrane and Although PK is known to have a longer course of visual
Atraumatic graft insertion is one of the main challenges. rehabilitation, BCVA of DSAEK at one-year follow-up was superior to
The techniques involve pushing or pulling the graft into the anterior that of PK at two- to three-year follow-up: PK patients ≥20/40 (0.3)
chamber. Initially, graft insertion was performed using McPherson was 55% and ≥20/25 (0.1) was 20%.
However, primary graft failure
forceps to position a folded donor posterior corneal disc into a taco- was more common in DSAEK at one-year follow-up.
This may be
like formation over a plastic glide into the recipient anterior chamber.
attributed to surgical technique.
Busin described a technique in which the donor tissue is pulled into
the anterior chamber with a microincision forceps through the In a patient survey comparing deep lamellar endothelial keratoplasty
opposite limbus to reduce trauma to the graft and limit endothelial loss (DLEK) and DSAEK, perception of quicker visual recovery was higher
compared with forceps insertion.
Using a 10-0 monofilament suture with DSAEK even though post-operative visual acuity was not
on a long straight needle to pull the graft through is another technique significantly different between the two groups. This may be attributed
that was found to have similar post-operative visual acuity, to fewer higher-order aberrations and limitations of surgery-induced
complications and endothelial cell counts to forceps-assisted hyperopia in DSAEK.
There was no statistically significant difference
Needle graft insertion techniques are also cost-effective.
in endothelial cell loss between DSEK and DSAEK at six or 12 months.
Intraocular lens (IOL) cartridges have also been used in ex vivo studies,
where the graft is ‘rolled’ into a compact shape to avoid compressive, Case reports of DSAEK in children have shown a more predictable
deleterious forces that occur as a result of folding.
Modifications of refractive outcome with less astigmatism and quicker recovery –
the glide and forceps techniques to reduce endothelial injury during crucial for amblyopia therapy – in comparison with PK.
insertion are currently under investigation.
integrity is also enhanced due to absence of sutures between the
host and graft in DSAEK.
Roughening the host peripheral stromal edges has demonstrated
better graft adherence.
Pre-soaking the grafts in balanced salt Complications
solution (BSS) Plus also significantly reduced graft detachment rates Graft dislocation is the most common complication in DSAEK,
in DSEK patients.
LASIK rollers have been used to centre donor grafts ranging from 1 to 50% in the literature,
and may be
and remove interface fluid.
Others have shown that air–fluid related to proper positioning of the graft with appropriate
exchange can be used to control anterior chamber pressure and pressurisation to maintain apposition. Terry et al. reported that
effectively tamponade the graft against the host stroma.
roughening the peripheral edges of the host stroma decreased
the graft dislocation rate to 4%. Post-operative re-positioning
Combined Procedures or re-injecting an air bubble (re-bubbling) can achieve graft
Combined procedures or ‘triple procedures’ include concomitant re-attachment in most cases.
A slit-lamp technique of draining
cataract extraction and IOL implantation with DSAEK.
IOL fluid at the wound interface successfully re-attached the donor disc
calculations can be performed with consideration of expected in five cases.
hyperopic shifts (1.25–1.50D) that occur with DSAEK. In Fuchs’
dystrophy patients, statistical comparison of post-operative visual Primary graft failure ranges from 0.5 to 5%,
with loss of endothelium
acuity showed no significant difference between those who as the predominant factor in histopathological evaluation of grafts.
underwent DSAEK only and those who had a triple procedure. As stated earlier, endothelial cell loss ranged from 20 to 57% in
The DSAEK-only group showed a larger hyperopic shift from the several studies.
This may be explained by many factors, including
pre-operative spherical equivalent than the triple procedure group. No surgical experience, inadvertent epithelial implantation during
significant difference in endothelial cell loss was noted between the lenticule preparation, retained Descemet’s membrane in the
two groups. Iatrogenic graft failure, or primary graft failure, was graft, epithelial ingrowth, fluid or material accumulation at the wound
defined as persistent post-operative corneal oedema that failed to interface (viscoelastic, neovascularisation, calcification),
clear within two months in a well-apposed graft; this was not de-centred grafts with full-thickness corneal layers at one edge or
observed in either of the groups.
chronic stromal changes from chronic corneal oedema.
72 EUROPEAN OPHTHALMIC REVIEW
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