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Page 12 of 14 Komzak et al. Mini-invasive Surg 2021;5:13 I http://dx.doi.org/10.20517/2574-1225.2020.103

The Preserflo microshunt (Santen Inc, Emeryville, CA, USA) previously known as the InnFocus microshunt
aims to address the need for a form of MIGS that can be effectively applied to moderate to severe
glaucoma. The Preserflo device is implanted into the subconjunctival space below Tenon’s capsule via an
ab-externo approach and threaded through a needle tunnel into the anterior chamber. The biocompatible
material of the Preserflo tube (SIBS) in combination with intraoperative Mitomycin C is used to reduce
[25]
the risk of scarring and fibrosis. Sadruddin et al. showed in a 23 patient post-market study of Preserflo
with and without phacoemulsification, a reduction from the mean baseline IOP in both groups of 23.8 ±
5.3 mmHg (26.4 mmHg in phacoemulsification combination group vs. 22.1 mmHg for Preserflo alone) to
10.7 ± 3.5 mmHg at 3-years follow-up (10.2 mmHg with phacoemulsification vs. 11.1 mmHg for Preserflo
alone). Medication reduction was 71% overall at 3 years, and 64% of participants no longer required topical
[25]
glaucoma medications .

Transient hypotony, shallow anterior chambers and the device touching the iris occurred in 13% of patients
individually, while transient choroidal detachment, hyphema and exposed Tenon’s capsule were also
common adverse events occurring in 9% of patients respectively. All of these issues resolved spontaneously
within 3 months of surgery being performed .
[25]
There is currently a lack of randomised control trials on the efficacy of Preserflo, however one RCT is
in progress and with more high-level evidence the safety and efficacy of this novel method will be made
increasingly clear in order to establish it as a viable option in OAG management.

MIGS targeting the ciliary process
Endocyclophotocoagulation: Mechanism of action, effectiveness and safety profile
Endocyclophotocoagulation (ECP) is a procedure that can be performed in conjunction with
phacoemulsification for refractory glaucoma and aims to reduce the production of aqueous humor by
the ciliary processes by shrinking these using a directed laser. ECP is generally indicated in end-stage
[21]
glaucoma. Pantalon et al. have demonstrated the efficacy of ECP through conducting a 12-month
retrospective study with patients receiving either 2 iStents, with concurrent ECP and cataract extraction,
or phacoemulsification and 2 iStents alone. The ECP procedure proved efficacious in reducing IOP from
a baseline value of 19.97 ± 4.31 mmHg to 13.05 ± 2.18 mmHg (a 35% reduction) compared with 17.63 ±
3.86 mmHg to 14.09 ± 1.86 mmHg (a 21% reduction) in the phacoemulsification and 2 iStent alone group.
Medications were also reduced from 2.22 ± 1.6 to 1.24 ± 1.05 in the ECP group and from 2.07 ± 1.02 to
1.39 ± 1.03 in the phaco-iStent alone group, a comparable reduction in both, and safety results were also
comparable. These results appear promising for the utilisation of ECP as a combined procedure with other
[21]
MIGS and cataract surgery .
There is, however, limited knowledge of the safety profile of ECP due to the lack of high-level evidence in
the form of randomised controlled trials. One study, currently in the data collection phase, is investigating
patients with POAG receiving either ECP with phacoemulsification or phacoemulsification as a standalone
[28]
procedure .

Emerging MIGS procedures
MINIject
The MINIject device (iStar Medical, Wavre, Belgium) is a 4 mm stent designed to follow the curvature of
the sclera and utilises porous silicone to allow aqueous outflow via the uveoscleral pathway. No studies
were identified investigating the MINIject device, and this is an area where more evidence is required
[29]
before a clear comment can be made about this form of MIGS .

Beacon aqueous microshunt