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The Challenge of Glaucoma Surgery in the Cataract Patient –
Where Are We Now?
Mildred MG Olivier
Professor, Department of Surgery, Division of Ophthalmology, Chicago Medical School, Chicago, US
Abstract Choosing the best approach for cataract removal in glaucoma patients depends on the extent of glaucoma-related damage and the
medications in use to control IOP. Micro-invasive glaucoma surgery offers additional options for patients needing combination surgery
without altering the conjunctiva.
Keywords Glaucoma surgery, cataract patients, phacoemulsification, trabeculectomy, micro-invasive glaucoma surgery
Disclosure: Mildred MG Olivier has nothing to disclose in relation to this article. No funding was received in the publication of this article..
Open Access: This article is published under the Creative Commons Attribution Noncommercial License, which permits any non-commercial use, distribution, adaptation
and reproduction provided the original author(s) and source are given appropriate credit.
Received: 1 December 2015 Published Online: 23 December 2015 Citation: European Ophthalmic Review, 2015;9(2):128–9
Correspondence: Mildred MG Olivier, Midwest Glaucoma Center, P.C., 1555 N Barrington Road, DOB #1, Suite 110, Hoffman Estates, Illinois 60169-1062, US.
Of the approximately 3 million cataract surgeries performed in the US
each year, epidemiologists predict that 10 % will have ocular hypertension
or open angle glaucoma (OAG). Ophthalmologists must be ready to handle
those surgeries as well as the 100,000 stand-alone glaucoma procedures.
Glaucoma patients present special challenges in cataract surgery. How
you proceed with cataract removal depends on the extent of glaucoma-
related damage to the optic disc and the medications in use to control
intraocular pressure (IOP). Patients with impaired outflow facility are
more likely to have post-operative IOP spikes; therefore, combining
cataract and glaucoma surgery is often recommended.
With myriad surgical options available for cataract removal, how do
you choose what’s best for your glaucoma patient? The options include
cataract surgery alone, filtration surgery (trabeculectomy [trab] or
glaucoma drainage device [GDD]) first followed by phacoemulsification
(phaco), or combining the two in one operation.
Choosing the best option depends on a number of factors. How severe
is the patient’s glaucoma, and how well will the optic nerve tolerate
IOP spikes associated with surgery? How many medications does
the patient take before surgery? What is the person’s age and ability
to follow a medical regimen? Does the patient have a desire to reduce
their dependence on medical therapy? The patient’s medical history,
ocular or systemic co-morbidities and glaucoma phenotype should
Patients and doctors see the appeal of combined procedures to
cut down on the number of trips to the operating room. There are
trade-offs, however. When considering whether to perform cataract
surgery alone or to combine it with filtering surgery, studies show that
combining procedures increases surgical risk and recovery time.
128 Cataract surgery alone may reduce IOP in both glaucomatous and
non-glaucomatous eyes. The mechanisms of reduced IOP may be
due to a wider anterior chamber angle, or the pull of the iris on the
ciliary body/scleral spur with widening of the trabecular beams. It
could also result from decreased aqueous production from low-grade
post-operative inflammation. In OAG, the IOP-lowering effect may
be transient. However, patients with angle closure glaucoma (ACG), or
narrow angles, may achieve a substantial and sustained reduction of
IOP due to relief of pupillary block.
With combined phaco-trab, studies have shown decreased risk of post-
operative IOP spikes, lower average IOP of 8 mmHg after 1 to 2 years
and a 1.5 % reduction in medications compared with patients’ baseline
measurements. In terms of the surgical approach, two-site, (clear
cornea phaco and superior trab), may be better than same-site (scleral
tunnel converted to a trab flap). Using anti-metabolite has been shown
to improve the outcome of same site surgery.
In patients with uncontrolled glaucoma, it might be advisable to perform
a trab well in advance of cataract surgery. Trab alone controls IOP better
than a phaco-trab. Studies found a reduction of 10.3 to 15.8 mmHg
after trab alone compared with 6.8 to 9.2 mmHg after phaco-trab.
However, trab is itself cataractogenic, with the accompanying intraocular
inflammation, flat AC, as well as the steroids required post-operatively.
The Advanced Glaucoma Intervention Study found a 78 % risk of visually
significant cataract within 5 years of trab. A flat anterior chamber and
marked inflammation increased the risk.
Cataract patients with pre-existing filtering blebs present another
concern as they may not work as well after cataract surgery. Among
patients with blebs, one study found 30.4 % required additional
medication or bleb needling and 9.6 % needed additional glaucoma
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