Modern Glaucoma Surgery

Modern Glaucoma Surgery

Preoperative Planning

A key step in preoperative planning for glaucoma surgery is to proactively manage patient expectations.

They should understand that the goal of surgery is to lower the IOP and prevent further damage, but does

not repair glaucoma damage that has already occurred. Unless their IOP is high enough to be

symptomatically painful (usually in excess of 35–40 mmHg), patients will not notice any changes in their

ocular status even if surgery is successful. Specifically, patients should be made to understand that their

vision will not improve after glaucoma surgery (unless a combined cataract and glaucoma surgery is

being performed). This is important because most patients know someone who had cataract surgery and

their vision improved, so they should be told that glaucoma surgery is different from cataract surgery. In

fact, visual acuity is often significantly blurred for several days to several weeks after glaucoma surgery;

this can be particularly significant in patients with only one sighted eye, as they can be functionally

impaired during the immediate postoperative period following glaucoma surgery. Patients should

understand that not every glaucoma operation is successful—IOP may not be improved postoperatively,

and the medication burden may be unchanged. The consent process for glaucoma surgery should also

include discussion of the small risk of complications that could cause reduction in or loss of sight in the

operative eye. These typically include bleeding and infection—both of which are rare but more frequently

seen after glaucoma surgery than cataract surgery. Finally, there is a miniscule risk of death related to

aggravation of underlying systemic co-morbidities (such as heart attack or stroke) or to reactions to

medications administered by the anesthesia team.

Patients should also be made aware of the relatively long recovery time and the need for frequent

postoperative evaluations. As is discussed in the following paragraphs, there are many potential

complications during the immediate postoperative period, many of which require intervention to ensure

optimal outcomes. Only with close monitoring through the postoperative period can these issues be

identified and addressed.

As with most surgical procedures, patients should be informed not to eat or drink anything after midnight

on the night before surgery. They should take all of their regular glaucoma medications, including those

scheduled for the morning of surgery, to prevent high IOP at the time of surgery, which can increase the

risk of intraoperative complications. Some surgeons also prefer to pretreat patients with several days of

topical antibiotics with or without topical anti-inflammatory therapy to prevent infections and reduce the

risk of exuberant healing.

Depending on the procedure planned, there may be materials that need to be ordered ahead of time.

These might include the antimetabolite (MMC or 5FU) to reduce scarring, the device to be implanted (for

example, Ex-PRESS, iStent, Ahmed, or Baerveldt tube-shunts), donor sclera or pericardium if a tube-

shunt is planned, and the intraocular lens implant if a combined procedure with cataract surgery is

planned.

Postoperative Follow-up and Care

Upon discharge from the surgical facility on the day of surgery, patients should be told to rest with

minimal activity, leave the patch and shield on the eye, and use none of their glaucoma medications in

the operative eye until otherwise instructed—although they should be reminded that they must continue to

use their glaucoma medications in the fellow, unoperated eye. If they have been on oral IOP-lowering

medications, these should not be taken after the surgery unless instructed by the doctor.

The first postoperative examination occurs the day after surgery. The key element of the history to be

recorded is pain, usually described on a scale of one to 10 and typically quite low for most glaucoma

procedures. The technician should carefully remove the shield and the eye patch and gently clean the

adhesive material from the skin around the eye. Visual acuity should be assessed, and if it is low, the

patient should be reassured that this is normal after glaucoma surgery and typically improves to

preoperative baseline within a few days to a few weeks. Most surgeons prefer to measure IOP

themselves on the first postoperative visit. It may be very high or very low, and neither is necessarily a

bad prognostic sign as the IOP on the first day does not predict surgical success or failure. After the

doctor has seen the patient, the patient should be reminded to faithfully administer both antibiotic and

steroid eye drops as directed and to wear the shield at night until told otherwise.