The Early Flat Anterior Chamber After Trabeculectomy
A Randomized, Prospective Study of 3 Methods of Management
Daniela S. Monteiro de Barros, MD,* Julia B.V. Kuntz Navarro, MD,*
Anand V. Mantravadi, MD,* Ghada A. Siam, MD,* Moataz E. Gheith, MD,* Ethan H. Tittler, BA,*
Karin A. Baez, MD,* Silvana M. Martinez, MD,* and George L. Spaeth, MD*w
filtration in glaucomatous eyes.1–3 Edmunds and co-
Purpose: To evaluate prospectively 3 different approaches to
authors,3 in a study of 1240 cases, found that 23.9% had
the management of a flat anterior chamber (FAC) because of
shallow AC (without iridocorneal touch) in the first 2
overfiltration in the early postoperative period after trabeculec-
postoperative weeks, 2.3% were found to have iridocorneal
touch and 0.2% had corneolenticular touch.3 Flat anterior
Materials and Methods: Thirty-six eyes diagnosed with a FAC with
chamber (FAC) after trabeculectomy is usually, but not
total iridocorneal touch, but no lenticular touch (grade II)
always, owing to decreased resistance to aqueous outflow
because of overfiltration in the first 14 days after trabeculectomy
through the sclera with resultant hypotony. It may be
were randomized prospectively into 3 groups: group 1—anterior
associated with the development of a choroidal effusion
chamber reformation with viscoelastic substance; group 2—
that may further decrease aqueous fluid formation. Left
anterior chamber reformation with balanced salt solution and
untreated, a FAC may lead to secondary complications,
concurrent drainage of choroidal effusion; and group 3—pharma-
including synechiae, cataract progression, and corneal
cologic therapy with atropine, phenylephrine, and in select casesoral acetazolamide. Outcome measures were visual acuity, amount
endothelial decompensation.4 In addition, posterior seque-
of intraocular pressure (IOP) reduction, and achievement of
lae of prolonged hypotony may ensue, such as persistent
choroidal detachment and hypotony maculopathy.5,6 Theincidence of FAC has decreased since the introduction of
Results: Treatment group 2 had a greater number of eyes
staged pressure reduction in the early postoperative
with acuity decline of two or more lines relative to group 3
period.7,8 However, an early FAC remains an important
(P = 0.04). Group 1 had more eyes with acuity decline of two ormore lines relative to group 3, but this was not significant
complication with the more commonplace use of adjunc-
tive antimetabolites9,10 and more aggressive target pres-sures.11,12
Conclusions: For grade II FACs because of overfiltration in the
A FAC is the situation in which there is contact
early postoperative period after trabeculectomy, reformation
between the posterior surface of the cornea and either the
of the anterior chamber with drainage of choroidal effusion
iris, lens, or vitreous. This has been classified anatomically
may be associated with greater long-term trabeculectomy success,but is associated with greater visual acuity loss relative to medicinal
into 3 stages (Fig. 1).13 A grade II FAC denotes contact
therapy alone. Reformation with viscoelastic resulted in a trend
between the entire iris and the corneal endothelium. This is
toward lowest final IOP in comparison to medicinal therapy
in contrast to grade I, in which iris/corneal touch is limited
to the periphery of the iris, and grade III, in which there isboth total iris apposition and also contact between the lens
Key Words: flat anterior chamber, glaucoma, intraocular pressure,
In this report, we refer only to those cases, which
involve the iris from the far periphery to the pupil margin(grade II FAC)13 as a consequence of insufficient resist-ance to aqueous outflow after filtration surgery for
arly flattening of the anterior chamber (AC) in associa-
Although there is general agreement that a grade III
tion with hypotony is an important complication after
FAC poses the greatest risk for subsequent corneal
trabeculectomy and other procedures designed to improve
decompensation and cataract progression, warranting moreurgent intervention, the management of an earlier stage ofFAC (grade II) is controversial.1,3,4,14 Expectant observa-
Received for publication October 8, 2007; accepted February 17, 2008.
tion with medicinal therapy,1,4,14 reformation of the AC
From the *William and Anna Goldberg Glaucoma Service, Wills Eye
Institute, Jefferson Medical College; and wDepartment of Ophthal-
with air or an ophthalmic viscoelastic substance,15–18 and
mology, Jefferson Medical College, Philadelphia, PA.
surgical drainage of choroidal effusion with AC reforma-
Supported by the Glaucoma Service Foundation to Prevent Blindness-
tion,19–22 have all been advocated for management of the
Glaucoma Service Foundation, Wills Eye Institute, Jefferson
The authors have no financial interest related to the article.
The purpose of this study is to evaluate prospectively 3
Statistical help was provided by Dr Ben Leiby from Jefferson Medical
different approaches to management of a grade II FAC:
watchful waiting; reformation of the AC with viscoelastic
Reprints: George L. Spaeth, MD, Wills Eye Hospital, 840 Walnut Street,
substance or reformation of the AC in association with
Suite 1110, Philadelphia, PA 19107 (e-mail: [email protected]).
Copyright r 2009 by Lippincott Williams & Wilkins
drainage of the choroidal effusion.
J Glaucoma Volume 18, Number 1, January 2009
J Glaucoma Volume 18, Number 1, January 2009
All cases in which a grade II FAC developed within 2
weeks of surgery were considered for enrollment. Patientswere enrolled in the study between 1985 and 1990, each casewithin 2 weeks of the time of surgery for that patient. Themedicinal management remained the same, except thatatropine 1% twice daily was added in all cases not alreadyreceiving atropine.
The cause for the FAC in all cases in the present study
was insufficient resistance to aqueous flow through thesclera. This was established by the following: measuringthe IOP to assure that IOP was below 8 mm Hg; testing theconjunctiva with fluorescein to assure that there wasno leakage through the conjunctiva; noting the presenceof a markedly elevated filtering bleb; questioning thepatient carefully regarding symptoms of any discomfort;and examining the fundus to rule out the possibility ofsuprachoroidal hemorrhage.
When a patient was identified within 2 weeks after
surgery as having a grade II FAC owing to insufficientresistance to outflow, the patient was examined thefollowing day. If the appearance of the AC had notchanged and the IOP remained low or was lower,the patient was considered for enrollment in the study. The medicinal management remained the same, except thatatropine 1% twice daily was added in all cases not alreadyreceiving atropine.
If after an informed consent the patient wished to
participate, he/she was randomly assigned to one of the3 groups of the study. Approval for this study was obtainedfrom the Institutional Review Board of Wills Eye Hospital.
Thirty-six phakic eyes of thirty-two patients met the
criteria for the study. Patients were enrolled between 1985and 1990 and randomized into one of 3 treatment groups:group 1: reformation of the AC with sodium hyaluronateviscoelastic material (Healon, Advanced Medical Optics,Santa Ana, CA); group 2: reformation of AC with BSS anddrainage of the choroidal effusion from the suprachoroidalspace; and group 3: medicinal therapy using atropine,phenylephrine, and, in select cases, a carbonic anhydraseinhibitor.
Randomization and initiation of treatment were
FIGURE 1. Classification of a flat anterior chamber. From
instituted in the first day after the diagnosis of grade II
Ophthalmic Surgery: Principles and Practice, 2nd ed. Philadelphia:
FAC. Stage of disease for all patients meeting enrollment
criteria was evaluated in terms of amount of optic disccupping (A = none or mild cupping, B = cupping tothe rim, and C = far-advanced cupping). Although demo-graphic data, preoperative visual acuity, and prior surgical
history were collected, they were not considered in
All 1191 trabeculectomies that constituted the source
of cases were performed with similar technique, by a singlesurgeon (G.L.S.), between 1985 and 1990. Neither relea-
sable sutures nor antimetabolites were employed and a
Under topical anesthesia, the AC was partially
rectangular scleral flap was made, with 1 scleral suture in
reformed with BSS, using a no. 30 gauge blunt cannula
each posterior corner and additional sutures in one or both
through the intraoperative paracentesis track previously
radial grooves as needed; these sutures were interrupted
fashioned. Sodium hyaluronate viscoelastic material (Hea-
using 10/0 nylon. In all cases, the AC was reformed with
lon) was introduced using a no. 30 gauge blunt cannula
balanced salt solution (BSS) at the close of the operative
connected to the ‘‘Healon’’ applicator, until the entire AC
procedure to assure there was adequate filtration through
was deemed as deep as or deeper than the fellow eye.
the sclera, no leakage through the conjunctiva, a well-formed AC that remained formed, and an intraocular
pressure (IOP) between 10 and 25 mm Hg, measured by
The surgical technique employed for drainage of
finger tension IOP estimation technique.23 All patients
choroidal effusions was similar to previously described
received topical antibiotic drops, prednisolone acetate
methods.19–22 The AC was reformed with BSS. The
1% four times daily and atropine 1% twice daily post-
conjunctiva was incised in the inferotemporal quadrant
4 to 8 mm posterior to the limbus. After hemostasis
J Glaucoma Volume 18, Number 1, January 2009
was achieved with light cautery, a 3-mm radial sclerotomy
The Wilcoxon rank sum test was used to determine if
with a no. 67 Beaver blade was made. Once the incision was
the distribution of loss of visual acuity defined as loss
completed, suprachoroidal fluid spontaneously drained.
of Snellen lines relative to pretrabeculectomy vision (non-
This was further facilitated by lifting the edges of the scleral
parametric data) differed between pairs of treatment groups.
incision; however, no instrument was placed through the
Categorical outcomes of reduction in IOP by 30%, achieve-
incision within the suprachoroidal space. After drainage of
ment of predetermined target IOP set by surgeon, trabecu-
fluid, the sclerostomy was closed with no. 7-0 polyglycolate,
lectomy failure as defined by IOP greater than 20 mm Hg on
followed with double layered closure of Tenon capsule and
medications, and the need for repeat surgery were examined.
conjunctiva with no. 8-0 chromic collagen. As noted prior,
The Fisher exact test was used to determine statistical
patients clinically suspected of having a suprachoroidal
significance of categorical data with smaller sample sizes.
hemorrhage were excluded from this study, and thus allpatients randomized had effusions that were presumed
serous based on preoperative clinical appearance. No
A total of 36 eyes of 32 patients were enrolled in this
patient randomized to group 2 was noted intraoperatively
study. The mean age was 56.8 ( ± 14.4) for group 1, 67.5
to have a hemorrhagic component to the fluid evacuated.
( ± 13.5) for group 2, and 65.3 ( ± 21.0) for group 3, with a
Postoperative care included topical antibiotics, predniso-
range of 22 to 85 across all groups. A large majority
lone acetate 1%, and atropine 1% four times daily, with the
of the patients enrolled were white (97%). Primary open-
selective addition of phenylephrine 2.5% in cases of poor
angle glaucoma comprised the diagnosis of 61% of
patients. Patient demographics and preintervention diag-noses are depicted in Table 1.
Of the 14 eyes of group 1, a grade II FAC developed
No surgical intervention was performed in group 3.
between the day of surgery and 11th day postoperatively
This group employed medicinal management with an initial
(mean ± SD = 4.3 ± 2.6 d); the 10 eyes of group 2 developed
course of atropine 1% one drop every 5 minutes
grade II FAC between the second and 11th day post-
for 4 doses, and phenylephrine 2.5% one drop every 5
operatively (5.0 ± 2.9 d); and the 12 eyes of group 3 developed
minutes for 4 doses, followed by atropine and phenyl-
grade II FAC between the second and 11th postoperative day
ephrine 4 times daily. Acetazolamide 250 mg orally was
(4.6 ± 2.5 d). Mean follow-up was 38.4 months for group 1,
given in 4 cases to suppress aqueous formation and
30.8 months for group 2, and 38.5 for group 3.
After initial treatment, 8 eyes in groups 1 and 2 were
Following institution of treatment, all patients were
considered to have failed initial treatment and required a
examined daily initially until deemed stable, and subse-
second procedure owing to reoccurrence of a grade II FAC.
quently at 1, 2, and 4 weeks, and between 3 and 12-month
Five of these eight eyes were from group 1 (viscoelastic
reformation). The second intervention was repeat reforma-
Failure of treatment was defined as the persistence or
tion with viscoelastic alone for 2 eyes. Surgical drainage of
reoccurrence of a grade II FAC. In patients who failed
the choroidal effusion with BSS reformation was performed
treatment, a second intervention identical to the first was
as the second intervention rather than repeat reformation
performed. However, if a second treatment identical to the
with viscoelastic alone for 2 eyes owing to the rapidity and
first was considered to present too high a risk in the opinion
severity of FAC reoccurrence at the discretion of the
of the surgeon based on certain clinical features or if failure
surgeon. Last, for 1 eye, repeat reformation with visco-
of treatment occurred a second time, then subsequent
elastic as the second intervention was followed later by a
intervention thought most definitive, decided by the
third intervention deemed most definitive, which was
surgeon’s discretion, was performed.
surgical drainage of choroidal effusion and reformation.
TABLE 1. Demographics and Preoperative Diagnosis of Patients Having Grade II Flat AnteriorChamber After Trabeculectomy
J Glaucoma Volume 18, Number 1, January 2009
TABLE 2. Comparison of Visual Acuity Preoperative and
TABLE 3. Success in Terms of Intraocular Pressure and
Postoperative in the 3 Different Groups and Stage of the Disease
Medications at Last Visit (1 Year ± 3 Months Postoperatively)
*Anterior chamber reformation with viscoelastic twice.
*Anterior chamber reformation with viscoelastic twice.
A indicates minimal cupping of optic nerve; B, moderate cupping; C,
advanced cupping; CF, count finger; HM, hand motion; LP, lightperception; VA, visual acuity.
cataract (patients 12, 9, and 21), and glaucoma progression(patient 19).
Table 3 summarizes postoperative IOP and number of
medications needed at final follow-up. Success in IOP
excluded the 3 group 1 patients whose subsequent inter-
lowering was defined as a decrease in IOP to the target
vention was surgical drainage, and a second analysis
range set preoperatively. This range is based on lowering of
at least 30%, modified for the glaucoma stage at the
The ‘‘last visit’’ (final follow-up) of the study was
around 1 year postoperatively for all cases; the range was
Table 4 represents results of the Wilcoxon rank sum
test for loss of visual acuity. In the comparison of surgical
Table 2 demonstrates the loss in visual acuity in
drainage of choroidal effusions (group 2) with medicinal
Snellen lines at final follow-up relative to pretreatment
treatment using atropine and phenylephrine (group 3), the
(pretrabeculectomy) acuity and indicates the relative
difference in loss of Snellen lines was statistically significant
disease stage of each patient. The mean loss of Snellen
(P = 0.04) with greater loss in the former treatment group.
lines was 1.2 ± 2.7 (mean ± SD) in group 1, 3.3 ± 3.2 in
Also represented in Table 4 are the Fisher exact test
group 2, and 0.5 ± 2.2 in group 3. Severe visual loss (SVL)
outcomes for reduction of IOP of 30%, achievement of
predetermined target IOP, failure with IOP>20 on
4 Snellen lines was limited to groups 1 (1 case) and 2
medications, and the need for repeat surgery owing to
(3 cases). The etiology of SVL in the patient in group 1 was
cataract and coexistent macular changes (patient 3). In
Table 5 represents a comparison of the 3 groups after
group 2, reasons for SVL included vein occlusion (patient 12),
J Glaucoma Volume 18, Number 1, January 2009
TABLE 4. Comparison of 3 Groups Having Only One Method of Management
Group 1: Reformation with viscoelastic substance as initial and only treatment. Group 2: Drainage of suprachoroidal space and reformation of anterior chamber is initial and only treatment. Group 3: Neither chamber reformation nor drainage of choroidal. *Visual acuity: P values for Wilcoxon rank sum test. All others categories P values for Fisher exact test.
wMedian (range) decrease in visual acuity. zIOP decreased > 30% with no medication.
yIOP target was set at the highest level the physician believed would not cause optic nerve damage. JRepeat surgery needed for recurrent grade II flat anterior chamber. IOP indicates intraocular pressure.
Figures 2 and 3 represent percentages of patients
evaluate prospectively the differences in outcomes of
in each treatment group who achieved target IOP and in
3 different strategies employed in the management of a
which IOP reduction of greater than 30% was achieved,
FAC because of overfiltration after trabeculectomy in the
respectively. Figure 4 demonstrates the number of Snellen
early postoperative period. Surgical revision of the scleral
lines lost among the 3 treatment groups.
flap with additional sutures, or tightening preexistingsutures to increase resistance to aqueous outflow is alsoan option, but was considered inappropriate in these cases,
as it was felt such a procedure might predispose to excessive
The reported incidence of FAC after trabeculectomy
varies widely from 2% to 41%.1–4,14,20,24–26 Reduction in
The combination of a low IOP, a high filtering bleb,
the incidence of early FAC after trabeculectomy has largely
absence of leakage through the conjunctiva, presence
been owing to modified techniques with graduated pressure
of an apparently open iridectomy, and no evidence of
reduction in the early postoperative course, using various
suprachoroidal hemorrhage reduced the likelihood that
releasable suture or laser suture lysis techniques,7,8 and/or
these FAC cases were caused by pupillary block, aqueous
the adjunctive use of intraoperative viscoelastics.27 None-
misdirection syndrome, or suprachoroidal hemorrhage.
theless, the early FAC after trabeculectomy remains an
Group 1 employed injection of viscoelastic substance
important complication. One of the factors driving the
for reformation of the AC. This technique has been
development of ‘‘nonpenetrating’’ surgeries for glaucoma,
advocated by some for short-term maintenance of chamber
such as deep sclerectomy, has been the desire to eliminate
depth after surgery to prevent further complications such
as corneal decompensation, cataract progression, or the
In phakic patients, a grade III FAC with lenticulo-
development of synechiae, choroidal detachment, and
corneal apposition is an indication for immediate surgical
aqueous misdirection syndrome.4,15–18 Furthermore, it has
reformation.4,28 However, in grade II FAC, the exact
become a frequently used method of treating FAC.16,18
timing and nature of initial intervention is less clear,
In many cases, especially before the availability of
ranging from conservative medicinal management to
viscoelastic substances, the standard treatment for FAC
surgical interventions.2,4,14,28 This report is an attempt to
following a filtration procedure was drainage of the
TABLE 5. Comparison of 3 Groups With Subsequent Interventions
Group 1: Reformation with viscoelastic substance as initial treatment, with 5 cases having repeat reformation—2 with viscoelastic and 3 with choroidal
Group 2: Drainage of suprachoroidal space and reformation of anterior chamber as initial and only treatment. Group 3: Neither chamber reformation nor drainage of choroidal. *Visual acuity: P values for Wilcoxon rank sum test. All others: relative risk and 95% confidence interval. P values for Fisher exact test.
wMedian (range) decrease in visual acuity. zIOP decreased > 30% with no medication.
yIOP target was set at the highest level the physician believed would not cause optic nerve damage. JRepeat surgery needed for flat anterior chamber. IOP indicates intraocular pressure.
J Glaucoma Volume 18, Number 1, January 2009
Percentage of Patients Treatment Groups
FIGURE 2. Patient achieved target intraocular pressure.
choroidal detachment and reformation of the AC with
anxiety and complexity of trying to save vision in a patient
saline solution. The outcome of drainage of choroidal
with glaucoma. When there are multiple options regarding
effusion with reformation of the AC as employed in group 2
management of a visual-threatening complication, consid-
in this study, was often associated with improved vision and
ering which may result in the greatest preservation of visual
acuity is relevant. Of the 33 eyes included in final analysis,
As it was known that many patients with overfiltration
15 patients (45%) lost two or more lines of visual acuity,
after trabeculectomy eventually spontaneously reform their
emphasizing the visual significance of the complications of
AC, ‘‘watchful waiting’’ has been advised by some as the
a FAC. Treatment groups 1 and 2 had a greater number of
appropriate treatment. In our study, in which surgeries
eyes with acuity decline of two or more lines (54% and
were performed without mitomycin-C, group 3 employed
60%, respectively) relative to group 3 (25%). The difference
nonsurgical measures associated with decreasing inflamma-
was statistically significant between groups 2 and 3
tion, modest deepening of the AC, and prevention of
(P = 0.04). Etiologies of visual decline in groups 1 and 2
pupillary block and posterior synechiae with a small pupil
included cataract or glaucoma progression, whereas a vein
while awaiting episcleral fibrosis at the filtration site to
occlusion occurred in 1 patient. This study, then, showed
increase the resistance to outflow and cause reformation of
that cases treated medicinally are less likely to lose vision
the chamber. More studies with mitomycin-C trabeculec-
than when a surgical intervention is performed (reforma-
tomies should be necessary to prove that watchful waiting
tion with viscoelastic or drainage of the choroidal detach-
An outcome of immediate importance to patients
The ultimate purpose of treatment is preservation of
is visual disability after an intervention.29 The ultimate
vision, and the way this is accomplished in patients with
purpose of performing a filtration procedure, such as
glaucoma is by lowering IOP. In fact, many studies of
trabeculectomy in a person with glaucoma, is to preserve
filtration procedures in glaucoma report rate of success only
vision. Complications that are vision threatening add to the
in terms of the amount of lowering the IOP.25,26 When
Percentage of Patients Treatment Groups
FIGURE 3. Fall of intraocular pressure >30%.
J Glaucoma Volume 18, Number 1, January 2009
Number of Lines Lost Treatment Groups
considering the ‘‘IOP success’’ in our study, we defined
treatment options, 2 of them (reformation of the AC with
success as achievement of predetermined target IOP, or
viscoelastic and medicinal therapy) seemed to be more
reduction of IOP greater than 30% relative to preoperative
reasonable than a third (choroidal drainage). We doubt
pressure without medications. In our cases, there was an
that enough funds and energy could be accumulated to
observed trend toward greater rates of success in groups 1
perform a randomized, controlled study of the approxi-
and 2 (Figs. 2, 3). These differences almost reached statistical
mately 900 cases that would be required to find small but
significance between groups 1 and 3 for absolute IOP
perhaps meaningful differences in outcomes. It would be
reduction of greater than 30% (P = 0.09). Though not
extremely difficult to assure that surgical technique was well
statistically significant, the trend of 91% (group 1), 70%
(group 2), and 58% (group 3) suggests that reformation with
This study represents the first attempt to analyze 3
viscoelastic is more likely to result in a satisfactory post-
modes of management of a FAC in a prospective,
operative IOP than treating the patient only with medica-
randomized fashion. A strength of this study was standar-
tions. It has been suggested that the very development of a
dization in the method of trabeculectomy—as a single
FAC leads to lower short-term postoperative success rates
surgeon performed all cases. Moreover, despite the sample
(2 to 8 mo) relative to eyes undergoing trabeculectomy that
size, one statistically significant finding emerged among the
3 treatment groups. Specifically, there seems to be little
The explanation for the apparent greater trend toward
justification for draining choroidal detachment in an eye
eventual lower IOP in groups 1 and 2 is not clear.
with grade II FAC. Also a possibly important trend
Reformation of the AC with a viscoelastic substance or
emerged, notably that when visual acuity preservation is a
BSS (with resultant immediate elevation of IOP) may
primary concern, medicinal treatment alone may be
encourage filtration by disruption of the filtration site. In
preferable, but when control of IOP is a high priority,
contrast, aqueous flow is decreased in eyes with hypotony/
reformation of the AC with a viscoelastic substance is a
choroidal detachment, and this may be decreased further by
use of aqueous suppressants; this is the theoretical basisbehind this intervention, which has been advised bysome.30–32 Possible disruption of the filtering area mayalso explain the increased tendency of eyes in groups 1 and
2 to develop recurrent FAC after intervention in compar-
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coMponEnts of tEchnoloGIcal KnowlEdGE: IndIcators of proGrEssIon lEvEl sEvEn Teachers should establish if students have developed robust level six understandings and are ready to begin working towards level seven achievement objectives for technological knowledge and plan learning experiences to progress these as guided by the level seven Indicators below. technologica