The versatile technique comes with short learning curve and combines well with MIGS.
A wealth of options exists for minimally invasive glaucoma surgery (MIGS) to reduce intraocular pressure (IOP) by improving the aqueous outflow through the trabecular meshwork. Endoscopic cyclophotocoagulation (ECP) has a different mechanism of action that lowers IOP by reducing the production of aqueous in the eye.
This makes it especially useful in combination with cataract surgery and other complementary MIGS procedures. ECP also has a short learning curve, so once you know the advantages and acquire a few surgical tips, you will be ready to incorporate the method into your armamentarium.
I use ECP to treat a wide range of patients with moderate to severe primary open-angle glaucoma, particularly if they have a heavy medication burden. Some stand-out advantages of the approach are as follows:
ECP’s unique mechanism of action makes it ideal to use in combination with other minimally invasive glaucoma surgeries. It is the only MIGS procedure that lowers IOP by controlling aqueous production, so combining it with other outflow-targeted procedures helps control the flow of aqueous in both directions.
When I am performing cataract surgery plus a MIGS trabecular meshwork procedure such as Hydrus (Ivantis), iStent (Glaukos), Kahook Dual Blade (KDB) (New World Medical), OMNI (Sight Sciences) and others, I can add ECP as well. My colleagues have published a study comparing cataract surgery with iStent implantation alone or with ECP, and they found that 12 months later, IOP was more than 2 mm Hg lower when they added ECP.1
One of the beautiful things about performing ECP is its versatility. It is a straightforward addition to a cataract procedure with MIGS, adding only a little bit more time for a worthwhile reduction in IOP and/or medications.
I also use ECP for pseudophakic patients who need better IOP control and welcome a reduction in medications. In pseudophakic cases, I typically choose KDB or OMNI along with ECP.
ECP is easy for surgeons to perform, with a skill set very similar to that for capsulorhexis. The eye is filled with viscoelastic, the instrument placed inside the eye and a separate monitor viewed as the laser performs the procedure, which takes just a short time.
It is titratable, so one can treat a lot or a little, depending on comfort level as the surgeon becomes accustomed to it. Compared to other MIGS procedures, ECP targets a larger area.
To start doing ECP, a few purchases need to be made. Firstly, there is the device itself (Endo Optiks E2). The probes are reusable but must be replaced eventually. To watch the procedure, a stand-alone monitor is also required.
I have found that the start-up costs are quickly recovered through reimbursements for ECP. The ECP procedure will be familiar to most surgeons.
The method is as follows. To begin, the anterior chamber should be filled with viscoelastic. To ensure adequate visualisation of the ciliary processes, enough space between the iris and the intraocular lens needs to be created by putting viscoelastic under the iris to make it bombe forward. ECP can treat approximately 200 degrees through a single incision, so one should plan for that.
Next, the device is inserted into the eye, with care taken not to bump into any intraocular structures. Achieving good focus and adequate lighting on the ciliary processes requires the help of an assistant. The light must be bright enough to enable the surgeon to see clearly, but not so bright that it is difficult to distinguish where your aiming beam is located.
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The laser should be carefully moved to the treatment area. Keeping about four to six ciliary processes in view will ensure an appropriate distance to deliver the desired power not too close (too high powered) or too far (ineffective power and greater likelihood that one could hit something other than the ciliary processes).
The surgeon should begin applying the treatment by gently painting the ciliary processes, moving in one direction. At the endpoint, one can gently go in the other direction. The process can be repeated on the other side.
The treatment should be observed during the procedure. When ECP is effective, the ciliary processes become whiter in colour and shrink. If the probe placement is correct but no effect is observed, the power of the laser can be gently increased.
If too much energy is applied, the processes can burst, causing a popping sound that startles the patient and can cause pain as well as some postoperative inflammation. With experience, you will soon become accustomed to doing this properly.
Postoperative medications are a bit different for patients who have ECP. For a standard cataract, cataract+MIGS, or cataract+MIGS+ECP, my patients get an intracameral antibiotic, corticosteroid, and non-steroidal drug. Postoperatively, cataract patients without ECP take one drop of a combination antibiotic, corticosteroid and non-steroidal drug once a day for 1 month.
When we add ECP, I prescribe the same medications, but with a stronger dose up front and a slower taper: four drops a day for 1 week and 2 drops a day for 3 weeks. The intracameral corticosteroids are very helpful.
I sometimes see a little bit more inflammation on day 1 compared with patients without ECP, but at 1 week, the eye is very quiet. And patients get those extra few points of IOP control that we know can not only help them limit medications, but perhaps prevent some progression over time.