Download Which Drops Do You Use Before and After Filtering Surgery?

THERAPEUTICS UPDATE
Which Drops Do You
Use Before and After
Filtering Surgery?
Three surgeons share their regimens.
BY ALLAN E. KOLKER, MD; E. RANDY CRAVEN, MD; AND HOWARD BARNEBEY, MD
ALL AN E . KOLKER , MD
The goal of surgery is to achieve ample filtration while
preventing infection and minimizing postoperative complications. The usual cause of failed filtering surgery is
postoperative inflammation, which leads to conjunctival
scarring that occludes the fistula/sclerectomy. Patients
who are taking miotics, especially echothiophate iodide,
are likely to develop inflammation after filtering surgery,
so they should stop instilling the drops at least 2 weeks
preoperatively. Such medications are used infrequently at
present. Other agents, however, are often associated with
topical/conjunctival hyperemia and allergies and should
be discontinued 1 to 2 weeks before surgery. Topical
adrenergics are the most common example.
I usually prescribe topical antibiotic drops 2 to 3 days
before filtering surgery and instruct patients to use the
medication for 1 week postoperatively. As with cataract
surgery, there is little evidence that the pre- and postoperative use of these agents is beneficial, but I continue to
prescribe them.
The most important drugs postoperatively are topical
corticosteroids, usually administered by my patients q2h
while awake for the first 2 weeks. They gradually decrease
their use of the drugs over the subsequent 2 to 3 weeks
and then discontinue them.
I administer antifibrotic agents intraoperatively and in
the office postoperatively. Generally, I inject 0.1 mL of
5-fluorouracil subconjunctivally into the inferior cul-desac twice weekly, starting 2 to 3 days postoperatively. I
continue this regimen for 2 weeks, depending upon the
degree of inflammation and the function of the bleb.
E . R ANDY CR AVEN , MD
Before surgery, I attempt to decrease the number of
IOP-lowering medications the patient is taking, but
34 I GLAUCOMA TODAY I JULY/AUGUST 2008
most of my patients cannot afford to discontinue these
agents prior to surgery because of advanced disease and
concerns about high IOPs. They begin administering a
topical antibiotic 3 days before surgery, but I do not
prescribe a steroid or NSAID for use preoperatively.
Immediately after surgery, patients discontinue all antiglaucoma medications, begin frequent dosing of topical
steroids, and continue using antibiotics for 1 week
(longer in cases of leaking wounds). I do not prescribe an
NSAID after filtering surgery.
If a patient’s IOP is elevated during the first few
months after surgery, I attempt to increase the trabecular outflow. The conventional outflow of aqueous is
through the trabecular meshwork. Filtration surgery
creates a new channel by which aqueous leaves the
eye, and trabecular atrophy occurs. My primary reason for trying to preserve and stimulate the trabecular
outflow system is that future surgeries may help to
lower the IOP through the conventional (trabecular)
outflow system. If the filter is failing, corrective action
is worth an attempt. I consider medications shown to
increase the trabecular outflow: pilocarpine (especially in pseudophakic eyes) and epinephrine (or dipivefrin) have been shown to stimulate the trabecular
outflow system. Unfortunately, these drugs have inflammatory and other side effects, and they frequently do not lower the IOP if the trabecular outflow system was not working before filtration surgery. There is
some evidence that brimonidine and bimatoprost
may increase trabecular outflow as well.1 I do not prescribe any steroids at this point unless significant inflammation is present.
Because the outflow medications usually do not work
after filtering surgery, aqueous suppressants are the
most practical and common means by which physicians
THERAPEUTICS UPDATE
lower IOP after trabeculectomy or shunting procedures.
Brimonidine decreases the production of aqueous
somewhat, and it also seems to increase outflow, probably uveoscleral.2 I have found that brimonidine is a useful adjunctive agent in patients after filtration surgery.
Decreasing the inflow of aqueous, even a little, seems to
reduce the IOP effectively if the filter is not adequately
controlling the IOP. Topical beta-blockers are quite useful in this regard as well, and topical carbonic anhydrase
inhibitors are also effective. Fixed-combination medications such as timolol/dorzolamide (Cosopt; Merck &
Co., Inc., Whitehouse Station, NJ) or timolol/brimonidine (Combigan; Allergan, Inc., Irvine, CA) are also excellent choices. I probably prescribe fixed combinations
the most after filtration surgery. Patients with encapsulated blebs respond very well to these agents.
I usually shy away from the prostaglandin analogs,
which I have found ineffective at reducing IOP after filtering surgery. The procedure itself may increase the
outflow of aqueous to such an extent that this class of
medications cannot add much. In my experience, however, prostaglandins are effective when the bleb is failing
or has almost failed.
H OWARD BARNEBEY, MD
For glaucoma surgeons, success or failure is often beyond the latitude of the surgical procedure itself. One
can liken glaucoma surgery to making the perfect golf
shot. Placing the golf ball in an ideal situation on the fairway is akin to ensuring the eye’s proper preparation for
surgery. The surgeon must address any ocular surface disease, dry eye, or medication-induced side effects before
wielding the scalpel. Among my glaucoma patients, I
continue to be surprised at the prevalence of disease and
inflammation of both the internal and external eyelid
margin. One need only consider the chronic irritation
from rosacea, meibomian gland dysfunction, or seborrheic blepharitis on the surface of the fledging bleb, as
the conjunctiva reacts to the changes created by a filtering procedure. For that matter, many of the topical medications for glaucoma can influence the integrity and
health of conjunctival surface cells as well as create a lowgrade inflammatory milieu. Often, I do not have the luxury of stopping the glaucoma medications themselves.
For these reasons, based on my preoperative assessment, I will often have patients begin taking topical
steroids (I currently favor loteprednol) for 1 to 3 weeks
before filtering surgery. If they have significant meibomian
gland dysfunction, I will ask patients to place warm compresses over their eyelids once or twice a day, supplement
their diet with omega-3 fatty acids (eg, flaxseed oil), and
begin taking a low dose (50 mg/day) of doxycycline.
36 I GLAUCOMA TODAY I JULY/AUGUST 2008
My perfect club and perfect golf shot are the selection and execution of the proper glaucoma procedure. I
may perform the time-honored trabeculectomy, implant a glaucoma seton, or perhaps perform a newer
procedure such as canaloplasty. Intraoperatively, I routinely use antimetabolites during trabeculectomy and
presently favor mitomycin C 0.25 to 0.30 mg/mL.
My patients use topical antibiotics for 7 days postoperatively. Taking a cue from my cataract colleagues, I
treat my patients aggressively with steroids and NSAIDs
immediately before and for a prolonged period after filtering surgery. They take NSAIDS for 3 weeks postoperatively. Like Dr. Kolker, I insist on the heavy use of topical steroids—five to six times a day (every 2 waking
hours) for 1 week, then t.i.d. for the next 2 to 6 months.
The appearance of the conjunctiva often dictates my
use of postoperative adjunctive medications such as
5-fluorouracil, mitomycin C, or bevacizumab to down
regulate the inflammatory process nonspecifically (this
use of these medications is currently off label). ❏
Howard Barnebey, MD, is a consultant for the
University of Washington in Seattle. He is
Medical Director and CEO of and is in private
practice with Specialty Eyecare Centres in Bellevue and Seattle, Washington. Dr. Barnebey is on
the speakers’ bureaus for Alcon Laboratories, Inc.; Allergan,
Inc.; Merck & Co., Inc.; and Pfizer Inc. He has received
research support from Alcon Laboratories, Inc., and
Allergan, Inc., and he is a consultant to Alcon Laboratories,
Inc. Dr. Barnebey may be reached at (425) 454-3937;
[email protected].
E. Randy Craven, MD, is in practice in Denver. Dr. Craven
is Associate Clinical Professor at University of Colorado
School of Medicine in Denver, and he is Director of Glaucoma Consultants of Colorado, PC, in Littleton. He is on the
speakers’ bureau for Allergan, Inc., and has received research support from Alcon Laboratories, Inc.; Allergan, Inc.;
and Merck & Co., Inc. Dr. Craven may be reached at (303)
797-1900; [email protected].
Allan E. Kolker, MD, is in private practice in
St. Louis. Dr. Kolker is Director of The Glaucoma
Institute and Professor of Clinical Ophthalmology at Washington University School of
Medicine, both in St. Louis. He is on the speakers’ bureaus for Alcon Laboratories, Inc., and Allergan, Inc.
Dr. Kolker may be reached at (314) 878-7747;
[email protected].
1. Brubaker RF. Targeting outflow facility in glaucoma management. Surv Ophthalmol.
2003;48(suppl 1):S17–S20.
2. Toris CB, Gleason MD, Camras CB, Yablonski ME. Effects of brimonidine on aqueous
humor dynamics in human eyes. Arch Ophthalmol. 1995;113:1514-1517.