The combination of microinvasive glaucoma surgeries with cataract surgery may address a patient's cataract and glaucoma in one procedure.
Although medications can achieve a similar effect - such as aqueous suppressants to reduce aqueous production and prostaglandins to increase aqueous outflow - ICE is a surgical option that addresses the patient's cataract and glaucoma in one procedure.
Patients ideally suited for ICE are those who are taking multiple medications and suffering from early onset open-angle glaucoma.
I typically start ICE with the 'C' component, namely, temporal clear corneal cataract surgery. Once the lens has been implanted, I begin the ECP by first removing the viscoelastic from the capsular bag. I then place Healon GV (Abbott Medical Optics, Santa Ana, California, USA) into the ciliary sulcus to optimize visualization of the entire ciliary process.
Next, I perform 360° of ECP followed by removing the viscoelastic from the ciliary sulcus. I place Miochol-E (Bausch + Lomb, Rochester, New York, USA) in the eye to bring down the pupil, which allows me to visualize the angle for implantation of the iStent. I place more Healon in the anterior chamber so that I can see the entire nasal angle and turn the patient's head away from me about 45° and tilt the microscope as well.
I use a surgical gonioprism, after placing some Healon on the cornea, to visualize the angle. I then implant the iStent through the cataract wound. Once I have made sure the wounds are sealed nicely and there are no leaks, I remove the speculum and the procedure is complete.
After the ICE, I prescribe a fluoroquinolone and difluprednate ophthalmic emulsion 0.05% (Durezol, Alcon Laboratories, Fort Worth, Texas, USA) for inflammation, to be administered quite aggressively every 2 hours, while awake, the day of the surgery.
I taper the use of the steroid drop rapidly after the first few days, and I monitor the eye for IOP spikes as a result of the steroids. If I find that the patient is having a steroid-response IOP spike, I may switch the prescription to a nonsteroidal anti-inflammatory drug or loteprednol etabonate ophthalmic gel 0.5% (Lotemax 0.5% Gel Drop, Bausch + Lomb).
Pearls for ICE
Placement of the iStent can also be assisted by the use of an endoscope (Endo Optiks) as opposed to a gonioprism. Using the endoscope to visualize the angle eliminates the need for repositioning the patient's head and microscope during the procedure.
The endoscope can also work as a stabilizer. I have often had patients with rapid movement of the eye, which can make implantation of the iStent somewhat difficult. Using the endoscope through a second port in the eye can stabilize the eye for easier and safer iStent implantation.
When I use it, I typically have to open up the paracentesis and I make sure the monitor is close enough to allow me to visualize the angle properly.
Why it works
As ECP and the iStent are microinvasive glaucoma surgeries (MIGS), they can be combined easily with cataract surgery. ECP can be done through the same wound as a cataract extraction, which, in my case, is a sub-2-mm procedure. ECP is appealing to patients, because it does not require sutures and therefore won't lead to scarring and astigmatism.
Furthermore, there is no foreign body sensation or issues with having an extraocular reservoir. The recovery for ECP and other MIGS procedures is essentially the same as cataract surgery, which is a substantial benefit to the patient and changes both the surgeon's and patient's attitude about glaucoma surgery from one of "surgery is the last line of defence against glaucoma", to bringing surgery on par with medical management and laser trabeculoplasty in the treatment algorithm.
Combining MIGS procedures is the future of glaucoma surgery. I predict we will see fewer trabeculectomies performed. Furthermore, mostly fellowship-trained glaucoma specialists, not general ophthalmologists, will do the few that are performed.
As more MIGS become approved by regulatory bodies, more procedures will be combined to improve results and streamline the patient's surgical experience. Any physician familiar with cataract, ECP and iStent implantation as individual procedures will have little to no learning curve when combining them for ICE.