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Bleb-less Surgery and Phaco – the iStent Saga
J Garcia Feijoo
Professor and Chairman, Department of Ophthalmology, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain; 2. Instituto de
Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain; 3. Cooperative Research Network on Age-Related Ocular Pathology, Visual and Life
Quality, Instituto de Salud Carlos III, Madrid, Spain
Abstract In the past years there is been a rapid evolution of cataract surgery; however, in glaucoma filtration surgery is still the ‘gold standard’.
New techniques and devices have been developed and may change the surgical algorithm. Minimally invasive glaucoma surgery
(MIGS) is safe, can be performed ab interno through sub-1.8 mm corneal incisions and a postop intraocular pressure in mid-teens can
Keywords MIGS, glaucoma, outflow, suprachoroidal, trabecular meshwork
Disclosure: J Garcia Feijoo is on the advisory board/consultor surgery for ALCON, Ivantis, Glaukos and Transcend and has been involved in trials supported by Glaukos,
Transcend, Ivantis and InnFocus. No funding was received in the publication of this article.
Received: 20 November 2014 Accepted: 2 December 2014 Citation: European Ophthalmic Review 2014;8(2):104–5
Correspondence: J Garcia Feijoo, Paseo de San Francisco de Sales 23. C-2. 10ºB. Madrid 28003, Spain. E: firstname.lastname@example.org
Glaucoma affects over 60 million people worldwide and after cataract
is the second leading cause of irreversible blindness; its prevalence is
increasing due to the ageing of the population. 1 If we consider the direct
and indirect costs of glaucoma there is an increase in the global cost
and the economic burden as glaucoma worsens. 2,3 Also the impact of the
disease on quality of life (QoL) of patients is important, especially in those
with advanced disease and bilateral visual field damage. 4
The only uncontroversial treatment modality that reduces the risk of
disease progression is intraocular pressure (IOP) reduction. 5 So the
main objective of glaucoma management is to preserve visual function
by achieving a stable and continuous IOP decrease through treatments
with a good safety profile and no repercussions on QoL. However, today
no therapeutic option has all these characteristics.
In the past 15 years we have witnessed the rapid evolution of cataract
surgery. Corneal incisions of 1.8–2.2 mm can be considered standard
and microincision cataract surgery (MICS) through sub-1.8 mm is
more and more common. This process has had a favourable impact on
the patient’s QoL. But in glaucoma surgery this evolution is still pending.
Filtration surgery (trabeculectomy and non-penetrating surgeries) is
the most effective way of reducing IOP and preventing the progression
of the disease, and though there is a variation on the surgical technique
among surgeons, it can be considered the ‘gold standard’ for the
majority of the patients that require surgery. But filtration surgery with
or without the adjunctive use of antimetabolites has been linked to
complications such as vision loss, bleb leak, inflammation, hypotony
and endophthalmitis. 6,7
So, and probably partially related to the fear of complications,
glaucoma surgery is usually performed when topical antiglaucoma
104 drugs and laser treatments fail to sufficiently reduce IOP or when
progression in detected. This trend has probably led to a delay in the
indication of surgery.
In the past years new surgeries have been developed and eventually
could be the driving force for a change in the paradigm of glaucoma
surgery. 8 The questions would be: do we really need aggressive
surgeries for all our patients, and if surgeries are undertaken, which
are less effective in terms of IOP-lowering effect, but with a very good
safety profile, they could help to increase the surgical indications for
the benefit of patients with early glaucoma and/or those not requiring
a very low IOP.
The new surgical approaches could be classified into two groups.
The first being those aimed at improving the safety consequences
on QoL and the reproducibility of the ‘conjunctival bleb dependent
surgeries’. These could be considered as ‘minimally penetrating’, but
their mechanism of action is still the conjunctival bleb. For this reason
the indications are similar to conventional filtration surgery. If these
surgeries demonstrated a better safety profile and similar outcomes
they could match conventional filtration surgery and eventually play an
important role in the ‘conventional treatment algorithm’, when IOP in the
low teens is required. Subconjunctival implants such us XEN (AqueSys
Inc., Aliso Viejo, US) or the InnFocus MicroShunt (InnFocus, Inc., Miami,
US) are examples of this approach.
The second approach is to increase the outflow, thus enhancing the
physiological drainage pathways. These techniques offer an IOP reduction
totally independent from the formation of a subconjunctival bleb and
there is no need for antimetabolites. Using an ab interno approach and
increasing the trabecular outflow or the suprachoidal drainage, these
could be truly considered minimally invasive glaucoma surgery (MIGS).
© Touc h ME d ic al ME d ia 2014