Clear Lens Extraction in Glaucoma (Is It Still a Controversy?)
In the last few years a few studies have been
published on the role of CLE in glaucoma. Tham et al.
have compared CLE with trabeculectomy. They
reported marginally better IOP control with
trabeculectomy in comparison to CLE (36% vs. 34%).
However, trabeculectomy operated eyes had more
frequent surgical complications (46% vs. 4%. P =
.0001)8. Dada et al. in their study performed CLE for
primary angle closure (PAC) patients. They reported
significant reduction in IOP and increase in the angle
opening distance (AOD) as well as in trabecular-iris
angle and reduction in glaucoma medications
following the procedure9. In another study, CLE was
compared with trabeculectomy and there was slightly
better lowering of IOP in the trabeculectomy group.
Finally, the most extensive analysis of CLE was
performed in “The Effectiveness in Angle-closure
Glaucoma of Lens Extraction” (EAGLE) study. In a
large multi-center trial conducted in 30 hospitals
across five countries patients with PAC/PACG
underwent CLE. The procedure was performed on 208
individuals who were followed up for three years. At
the end of the study, mean IOP was 1 mm Hg lower in
the CLE group compared to the standard-care group
(medications and PI). Further treatment was required
in 21% patients who underwent CLE compared to
61% in the other group. The CLE group also reported
less frequent need for surgical intervention (one vs. 24
in the standard-care group)10.
advisable to opt for glaucoma filtering surgery rather
than CLE11. The ideal candidate for CLE is someone
having only mild damage and whose IOP is within
target range on well tolerated glaucoma medications.
Certain factors have to be considered while deciding
for CLE vs. combined surgery vs. trabeculectomy
alone. These include: patient characteristics, severity
of glaucoma, the potential visual outcome after lens
extraction and target IOP to be achieved. In certain
cases, minimally invasive glaucoma surgery (MIGS)
or goniosynechialysis can be combined with CLE.Pre-
existing structural trabecular damage in PACG eyes
may not lead to effective lowering of IOP after lens
extraction alone. Such patients would do better with
combined phaco-trabeculectomy. CLE can be
considered if there is increased lens thickness or lens
vault and no significant trabecular dysfunction or
glaucomatous optic nerve degeneration is present. In
such situations CLE may prove curative12.
Lens extraction is the only surgical modality that
changes the anatomy of the angle, which is a
predisposing factor for angle closure. Lens removal
deepens the anterior chamber and thereby relieves
angle crowding.13 Shingleton has mentioned that
cataract extraction should not replace combined
surgery in the glaucoma population; instead it can be
an appropriate choice in a compliant glaucoma patient
on one or two medications pre-operatively with
otherwise stable visual fields and optic nerves.14 CLE
can be considered if topical treatment does not control
IOP and PI does not have a positive effect on the angle
closure. This is especially effective if there is only
appositional angle closure and anterior segment
imaging shows the lens contributing significantly to
the angle closure. It is essential to weigh the benefits
of CLE with disadvantages such as loss of
accommodation, stress of surgical intervention on the
patient and surgeon, technical difficulties and the
intra- and post-operative complications which may
occur more frequently in this group compared to
normal eyes15.
While undeniably there are multiple advantages of
CLE it is necessary to emphasize that this procedure is
not a one-stop solution for all cases of PACG. The
possibility of trabecular meshwork dysfunction and
post-trabecular mechanisms for the development of
glaucoma have to be kept in mind. CLE may not be
effective in such cases. The management of PACD
depends upo1n a number of aspects including the stage
of the disease and correctly identifying the underlying
mechanisms. The surgical option should be dictated by
a holistic consideration of all factors and not just
lowering of IOP.
CLE alone may possibly be an alternative to
trabeculectomy as an initial surgical option in
medically uncontrolled, iridotomized eyes without
cataract. It is debatable if CLE can be an alternative to
iridotomy. CLE can be preferred in patients prone to
or who cannot accept the potential complications of
trabeculectomy with anti-fibrotic agents such as
mitomycin-C. In situations which require a more
urgent need to reduce the number of medications it is
In conclusion, there appears to be widening
acceptance of CLE in selected cases. Glaucoma
management has to be individualized and when
situation demands such techniques can be successfully
employed. The procedure is relatively safe, validated
by our experience of clear lens exchange for refractive
errors, effective and shows a positive impact on the
quality of life of the individual by reducing
dependence on glaucoma medications. There is need
Pakistan Journal of Ophthalmology, 2020, Vol. 36 (2): 93-95
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