antimetabolites in patients with primary open angle glaucoma. He reports statistically significant lower lOP in the trabeculectomy group throughout the study ...
Improving glaucoma
MARIA PAPADOPOULOS, PENG T. KHAW
filtering surgery Since 1857, which saw the birth of successful
medications, survival analysis demonstrated
glaucoma surgery with von Graefe's
93% attained this in the trabeculectomy group
iridectomy, many procedures have come and
as opposed to 45% in the NPDS group at 18
gone but only a few have stood the test of time.
months. However, trabeculectomy was
Cairns' 'guarded sclerostomy'
associated with more early post-operative
(trabeculectomy)l is one such operation. It
complications in the form of hyphaema and a
replaced full-thickness filtering procedures to
greater need for subsequent cataract surgery.
become the procedure of choice because, having
These findings are similar to those of Gandolfi
first proved to be equally successful in lowering
and Cimin08 and even to those of Carassa9 who
intraocular pressure (lOP), its superiority lay in
compared trabeculectomy with
the fact it was a safer operation with relatively
viscocanulostomy but with a shorter follow-up.
fewer risks of complications.
However, recently published results by El
This continuing quest for safer glaucoma
Sayyad et a/.lD comparing trabeculectomy and
surgery is what has recently motivated
NPDS without adjunctive implant, instead
surgeons to revist non-penetrating trabecular
suggest a comparable final lOP and mean lOP
surgery. It was first described almost 30 years
reduction. But, in contrast to Chiselita's study,
ago with the aim of avoiding the potential
these results were achieved with goniopuncture
complications associated with ocular entry?
in 10% of the NPDS group and 5-fluorouracil
Following more recent modifications it has been
injections. Interestingly, EI Sayyad et al.lO did
promoted as a serious alternative to
not detect a significant difference in the rate of
trabeculectomy, largely for its more attractive
complications. Studies such as Chiselita's should be
complication profile.3,4 However, with increasing recognition that lOPs in the low teens
commended not only for giving us a perspective
are required to prevent or minimise glaucoma
as to where NPDS fits in our surgical
progression,5,6 the degree of long-term lOP
armamentarium, but also for highlighting the
control achieved by a new technique should be
fact that our current gold standard is far from
the primary measure by which it is judged and
ideal. So, while we encourage the development
which ultimately determines its place in the
of effective, safer operations we should continue
management of glaucoma. Furthermore, any
to 'fine-tune' a time-proven technique to
procedure which now desires the 'gold
achieve both satisfactory lOP control and a
standard of treatment' title must challenge for it
lower rate of complications. With regard to the
in the ring of prospective, randomised
prevention of complications, most of our
controlled trials. Complication profile aside, it
attention has focused on dealing with those that
must prove to have at least the same degree of
occur in the early post-operative period. For
efficacy as the procedure it intends to replace
example, the introduction of post-operative
before it can be considered a serious contender.
scleral flap suture release has been a major
The results of some of these prospective,
advance in terms of the prevention of early
randomised studies are now becoming available
hypotony. However, bleb morphology and its
to suggest that the short-term gain of a lower
role in late complications, such as bleb leaks and
rate of complications seen with non-penetrating
infection, has been largely ignored despite its
P.T. Khaw
deep sclerectomy (NPDS) is at the expense of
known relationship to wound construction. Yet
Glaucoma Unit and Wound
long-term bene'Iit in the form of adequate lOP 7 control. The study by Chiselita in this issue
by encouraging posterior, unrestricted drainage
compares NPDS without adjunctive implant to
conjunctival flap,11,12 an increase in
trabeculectomy, with no post-operative use of
antimetabolite treatment area13 and a large flap
antimetabolites in patients with primary open
with suturing that promotes posterior rather
angle glaucoma. He reports statistically
than lateral flow, it may be possible to achieve
significant lower lOP in the trabeculectomy
the much desired diffuse, non-cystic bleb.14
group throughout the study along with a
of aqueous with the use of a fornix-based
No operation is immune to complications and Cairns' trabeculectomy, the gold standard
trabeculectomy (35.7%) as compared with
of glaucoma surgery, is no exception. Our
NPDS (25.1%) at 18 months. When success was
response to this can be threefold: we can
defined in terms of lOP
