J CATARACT REFRACT SURG - VOL 32, JUNE 2006

Effect of temporal clear corneal

phacoemulsification on intraocular

pressure in eyes with prior Ahmed glaucoma

valve insertion

Ho-Seok Sa, MD, Changwon Kee, MD

PURPOSE: To evaluate the effect of temporal clear corneal phacoemulsification on intraocular pres-sure (IOP) in eyes after Ahmed glaucoma valve insertion.

SETTING: Department of Ophthalmology, Sungkyunkwan University School of Medicine, SamsungMedical Center, Seoul, Korea.

METHODS: The files of 13 patients who received phacoemulsification after Ahmed glaucoma valveinsertion were reviewed in this retrospective case series. Visual acuity, IOP, and the number of glau-coma medications before phacoemulsification were used as a baseline for comparison with the valuesat various follow-up intervals.

RESULTS: The mean IOP before phacoemulsification was 15.1 mm Hg G 3.6 (SD). Postoperatively, itwas 12.8 G 4.5 mm Hg, 13.1 G 3.6 mm Hg, 16.4 G 5.2 mm Hg, 15.8 G 4.0 mm Hg, 16.1 G 3.9 mmHg, 15.3 G 4.1 mm Hg, and 15.2 G 3.4 mm Hg at 1 day after 1 week, at 1, 2, 6, and 12 months, andat last visits, respectively. The mean IOP did not differ significantly from the prephacoemulsificationvalue at any follow-up. The number of glaucoma medications increased significantly after phacoemul-sification (P Z .031), and 6 of 13 eyes required additional glaucoma medication because of IOP eleva-tion at approximately 1 month.

CONCLUSIONS: Temporal clear corneal phacoemulsification did not increase IOP significantly in eyeswith prior Ahmed glaucoma valve insertion. However, some eyes experienced an IOP elevation 1month after phacoemulsification and required glaucoma medication.

J Cataract Refract Surg 2006; 32:1011–1014 Q 2006 ASCRS and ESCRS

Many patients who have had glaucoma surgery ultimatelyrequire cataract extraction. However, cataract extraction

after glaucoma surgery may reduce bleb function and result

in a higher intraocular pressure (IOP).

Several studies have reported that 20% to 40% of

eyes with previous trabeculectomy require additional

Accepted for publication December 1, 2005.

From the Department of Ophthalmology, Sungkyunkwan Univer-sity School of Medicine, Samsung Medical Center, Seoul, Korea.

Neither author has a financial or proprietary interest in any mate-rial or method mentioned.

Reprint requests to Dr. Changwon Kee, Department of Ophthal-mology, Samsung Medical Center, 50 Ilwon-dong, Kangnam-ku,Seoul, 135-710, Korea. E-mail: cwkee@smc.samsung.co.kr.

Q 2006 ASCRS and ESCRS

Published by Elsevier Inc.

glaucoma medication to control IOP within 3 years afterphacoemulsification.1–3 However, another study4 reported

that cataract surgery by temporal corneal phacoemulsifica-

tion in eyes with superior filtering blebs after trabeculec-

tomy does not adversely affect long-term IOP control.

Although the Ahmed glaucoma valve is used commonly

in refractory glaucoma, to our knowledge, no study has

evaluated the effect of phacoemulsification on IOP in

eyes with prior Ahmed glaucoma valve insertion. In thisretrospective analysis, the effects of temporal clear corneal

phacoemulsification on IOP control in eyes with prior

Ahmed glaucoma valve were evaluated.

PATIENTS AND METHODS

The medical records of 13 eyes of 13 patients who had tem-poral corneal phacoemulsification at least 3 months after Ahmed

0886-3350/06/$-see front matterdoi:10.1016/j.jcrs.2006.02.031

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EFFECT OF PHACOEMULSIFICATION ON IOP IN EYES WITH GLAUCOMA VALVE

glaucoma valve (New World Medical Inc) insertion were reviewed.Data such as visual acuities, IOPs, and number of glaucomamedications were obtained before phacoemulsification, and post-operatively at 1 day; 1 week; 1, 2, 6, and 12 months; and at lastfollow-up visits.

One surgeon (C.K.) performed all surgeries, ie, Ahmed glau-coma valve insertion and phacoemulsification in all patients. ForAhmed glaucoma valve insertion, a blunt dissection of Tenon’scapsule and conjunctiva was performed to clear a space on thesclera in the superotemporal quadrant. The Ahmed glaucomavalve was then placed and fixated to the sclera with 2 interrupted9-0 nylon sutures. The Ahmed glaucoma valve tube was posi-tioned over the cornea to determine the required length; its tipwas cut at a 30-degree angle. A track was then made 1.5 mm pos-terior to the limbus into the anterior chamber with a 23-gaugeneedle, and the Ahmed glaucoma valve tube was placed in theanterior chamber and confirmed to be in an appropriate position.A rectangle of approximately 4 mm� 6 mm of donor pericardiumwas sutured over the tube to the sclera using 4 interrupted 8-0polyglactin (Vicryl) sutures. Tenon’s capsule and conjunctivawere then repositioned and sutured back in place with running8-0 polyglactin (Vicryl) sutures. No antimetabolites were usedintraoperatively or postoperatively.

No patient needed further glaucoma surgery, and all had anIOP lower than 22 mm Hg with or without the use of glaucomamedications before cataract surgery. Cataract extraction was indi-cated when lens opacities impaired visual function or when leuko-coria caused a cosmetic problem.

Phacoemulsification was performed using a 3.0 mm temporalclear corneal incision without manipulation of the conjunctiva orfiltering bleb. After crystalline lens removal, a foldable siliconeposterior chamber intraocular lens (IOL) (SI-40NB, AdvancedMedical Optics Inc.) was placed in the capsular bag in all cases.Postoperative treatment consisted of topical antibiotics and topi-cal steroids for 4 weeks.

The differences between baseline IOP (before phacoemulsifi-cation) and IOPs at each follow-up point in the eyes with priorAhmed glaucoma valve insertion were analyzed using the pairedt test or Wilcoxon signed rank test with Bonferroni correction.The number of glaucoma medications administered before and af-ter phacoemulsification was tested using the Wilcoxon signed ranktest. The null hypothesis was rejected for P values less than 0.05.

RESULTS

Thirteen eyes of 13 patients who had successful Ahmed

glaucoma valve insertion were enrolled in the current study.

Patients’ demographics are shown in Table 1. Most patients

(78%) had a diagnosis of neovascular glaucoma, and others(22%) had uveitic glaucoma. No complications occurred

during or after phacoemulsification, and no eye required

additional glaucoma surgery.

Mean IOPs before and after phacoemulsification are

shown in Figure 1. Mean IOP immediately before phaco-

emulsification was not significantly different from the mean

IOP at any follow-up point (PO.05, paired t test or Wilcoxon

signed rank test with Bonferroni correction). Although thechanges were not significant, mean IOP 1 month after pha-

coemulsification increased by 4 mm Hg or more in 6 patients

(46.2%), and 1 of them had an IOP spike (10 mm Hg).

J CATARACT REFRACT SURG1012

Figure 2 shows medication changes for each patient

after phacoemulsification by comparing the patient medica-

tion number profile before surgery with that at the last fol-

low-up. The number of glaucoma medications prescribed

after phacoemulsification was significantly greater than

that before phacoemulsification in eyes with prior Ahmedglaucoma valve insertion (P Z .031, Wilcoxon signed

rank test). After phacoemulsification, 7 patients (53.8%)

required the same number of medications, but 6 patients

(46.2%) who had not required medication before phacoe-

mulsification subsequently required 1 or 2 glaucoma medi-

cations for IOP control. Five (83.3%) of these 6 patients

needed glaucoma medication approximately 1 month after

phacoemulsification, and 1 patient needed medication at5 months. All eyes with additional glaucoma medication

continued to require the same number of medications.

Ten patients (76.9%) had a preoperative visual acuity

worse than finger counting because of preexisting retinal

problems, which included retinal detachment, proliferative

diabetic retinopathy, or central retinal vein occlusion, and

had phacoemulsification for cosmetic purposes. However,

the remaining 3 patients had visual acuity improvementsfrom 20/400, 20/200, and 20/100 to 20/40, 20/30, and

20/50, respectively.

DISCUSSION

Cataract is a common problem in patients who have

had glaucoma surgery because cataract and glaucoma areindependently common in the elderly and glaucoma

surgery may accelerate cataract formation in eyes with

a shallow anterior chamber, postoperative hypotony, or

excessive inflammation.5,6

Glaucoma drainage implants are used commonly in

patients with glaucoma refractory to trabeculectomy or in

patients with neovascular, traumatic, or inflammatory glau-

comas.7 The Ahmed glaucoma valve is 1 of the most com-monly used glaucoma drainage implants because hypotony

and its attendant complications during the immediate

postoperative period are less common than with other

Table 1. Patients’ demographics.

Characteristic Value

No. of eyes (patients) 13 (13)Mean age (y) G SD 54.8 G 17.6Sex (male/female) 8/5Mean interval between glaucoma surgery

and phacoemulsification (mo)16.2 G 14.0

Mean follow-up (mo) 19.0 G 15.0Diagnosis, n (%)Neovascular glaucoma, n (%) 11 (78)Uveitic glaucoma, n (%) 2 (22)

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EFFECT OF PHACOEMULSIFICATION ON IOP IN EYES WITH GLAUCOMA VALVE

15.1(3.6) 12.8

(4.5)

13.1(3.6)

16.4(5.2)

15.8(4.0)

16.1(3.9)

15.3(4.1)

15.2(3.4)

0

5

10

15

20

25

Before 1 day 1 wk 1 mon 2 mon 6 mon 12 mon LastTime Post Phacoemulsification

IOP

(mm

Hg)

bars

indi

cate

sta

ndar

d de

viat

ion

N = 10 1313 131313 1313

Figure 1. Evolution of mean (G SD) IPOs in eyes

having phacoemulsification after Ahmed glaucoma

valve insertion.

implants.8 With an increase of the use of the Ahmed glau-

coma valve, cataract in eyes with a functioning Ahmed

glaucoma valve may also be a challenging problem. How-

ever, the effect of phacoemulsification on IOP or implant

function has not been reported previously.

In this study, the mean IOP did not differ significantly

from the prephacoemulsification value at any follow-up,but the number of glaucoma medications at the last follow-

up was significantly greater than before phacoemulsification

The mean time from Ahmed glaucoma valve insertion was

approximately 16 months for the prephacoemulsification

point, and 35 months for the last follow-up point. For histor-

ical comparison, we reviewed 3 studies9–11 on Ahmed

5/13

1/13

7/13

0%

10%

20%

30%

40%

50%

60%

70%

Change in Number of Medications0 1 2

Figure 2. Change in number of antiglaucoma medications before pha-

coemulsification to the last follow-up. The first number indicates the

number of patients who received medication, and the second number

indicates the total number of patients.

J CATARACT REFRACT SUR

glaucoma valve insertion that had sufficiently large numbers

of patients and long follow-up periods. Huang et al.9 (159

eyes) reported 14.8 mm Hg at 12 months and 12.6 mm Hg

at 36 months; the number of medications changed from

1.3 to 1.0 during the same follow-up periods. Wilson

et al.10 (59 eyes) reported 14.2 mm Hg at 14 to 18 months

and 12.5 mm Hg at 34 to 40 months. Wang et al.11 (18 eyes)reported 15.9 mm Hg at 12 months and 15.0 mm Hg at

24 months. Despite limitations of historical comparison, at

the similar follow-up points IOP was not significantly

changed, but an increase in number of medications was

observed in our study. This shows phacoemulsification may

adversely affect the bleb of the Ahmed glaucoma valve. Clamp-

ing the tube during phacoemulsification to prevent flow

of cataract debris into the bleb of the Ahmed glaucoma valvemay decrease the number of antiglaucoma medications after

surgery.

Casson et al.12 reported that an incisiondcorneal or

scleraldlarger than 4.0 mm is a significant risk factor for

loss of IOP control in eyes with functioning bleb. In the cur-

rent study, a 3.0 mm temporal corneal incision was used in

all patients, thus avoiding the influence of a larger incision

on filtering blebs. Chen et al.13 reported that an interval offewer than 6 months between trabeculectomy and cataract

surgery significantly contributes to the risk for IOP eleva-

tion. The mean interval in their study was sufficiently

long (16.2 G 14.0 months), although the type of glaucoma

surgery was different. Most of our patients who had cataract

surgery had maintained well-controlled IOPs before pha-

coemulsification because most of the uncontrolled patients

did not want to have cataract surgery.In this study, 6 eyes (46.2%) had an IOP elevation of

4 mm Hg or greater 1 month after phacoemulsification; 5

of these required additional glaucoma medication for IOP

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EFFECT OF PHACOEMULSIFICATION ON IOP IN EYES WITH GLAUCOMA VALVE

control. The mechanism of IOP elevation is not clear, but

intraocular factors after phacoemulsification may stimulate

postoperative fibroblastic activity, inflammatory cells, and

growth factors in aqueous flow from the anterior chamber

through the tube into a subconjunctival space in the bleb.

We assume that the penetration of fibroproliferative media-tors into the bleb wall might occur diffusely over the plate,

and subsequent fibrovascular encapsulation could explain

an IOP elevation postoperatively. Additionally, all our

patients had a diagnosis of neovascular or uveitic glaucoma,

and this fibroproliferative process could easily occur

because of the vulnerability to the breakdown of the

blood–aqueous barrier.

The sample size in this study was quite small because ofthe rarity of phacoemulsification after Ahmed glaucoma

valve insertion because most patients with an Ahmed

glaucoma valve cannot expect visual improvement from

cataract surgery because of preexisting retinal problems.

In our study, 10 of 13 patients had phacoemulsification

for cosmetic purposes only. Most patients had poor vision

before Ahmed glaucoma valve insertion; however, the

patients were relatively young. Therefore, we performedmore physiological surgery (Ahmed glaucoma valve inser-

tion) rather than cyclodestruction when glaucoma surgery

was required. It was because cyclodestruction could result

in phthisis bulbi more frequently, which was a significant

complication in consideration of their life expectancy. We

also tried to control IOP elevation with medication after

phacoemulsification to prevent complete visual loss in

this study.The limitations in the current study stem from a small

sample size and a retrospective uncontrolled design. Fur-

ther studies with large samples could provide important

supplementary data to validate our findings.

Phacoemulsification using a temporal corneal incision

had little effect on mean IOP in patients who had prior

Ahmed glaucoma valve insertion. However, some eyes

J CATARACT REFRACT SUR1014

with an Ahmed glaucoma valve had an IOP elevation

1 month after phacoemulsification and required continued

use of glaucoma medications. Therefore, an IOP elevation

should be considered after cataract surgery with previous

Ahmed glaucoma valve implantation eyes.

REFERENCES

1. Halikiopoulos D, Moster MR, Azuara-Blanco A, et al. The outcome of

the functioning filter after subsequent cataract extraction. Ophthal-

mic Surg Lasers 2001; 32:108–117

2. Casson R, Rahman R, Salmon JF. Phacoemulsification with intraocular

lens implantation after trabeculectomy. J Glaucoma 2002; 11:429–433

3. Rebolleda G, Munoz-Negrete FJ. Phacoemulsification in eyes with

functioning filtering blebs: a prospective study. Ophthalmology

2002; 109:2248–2255

4. Park HJ, Kwon YH, Weitzman M, Caprioli J. Temporal corneal phacoe-

mulsification in patients with filtered glaucoma. Arch Ophthalmol

1997; 115:1375–1380

5. D’Ermo F, Bonomi L, Doro D. A critical analysis of the long-term results

of trabeculectomy. Am J Ophthalmol 1979; 88:829–835

6. Mills KB. Trabeculectomy: a retrospective long-term follow-up of 444

cases. Br J Ophthalmol 1981; 65:790–795

7. Schwartz K, Budenz D. Current management of glaucoma. Curr Opin

Ophthalmol 2004; 15:119–126

8. Coleman AL, Hill R, Wilson MR, et al. Initial clinical experiences with the

Ahmed glaucoma valve implant. Am J Ophthalmol 1995; 120:23–31;

errata 684

9. Huang MC, Netland PA, Coleman AL, et al. Intermediate-term clinical

experience with the Ahmed glaucoma valve implant. Am J Ophthal-

mol 1999; 127:27–33

10. Wilson MR, Mendis U, Paliwal A, Haynatzka V. Long-term follow-up of

primary glaucoma surgery with Ahmed glaucoma valve implant

versus trabeculectomy. Am J Ophthalmol 2003; 136:464–470

11. Wang J-C, See JLS, Chew PTK. Experience with the use of Baerveldt

and Ahmed glaucoma drainage implants in an Asian population.

Ophthalmology 2004; 111:1383–1388

12. Casson RJ, Riddell CE, Rahman R, et al. Long-term effect of cataract

surgery on intraocular pressure after trabeculectomy; extracapsular

extraction versus phacoemulsification. J Cataract Refract Surg 2002;

28:2159–2164

13. Chen PP, Weaver YK, Budenz DL, et al. Trabeculectomy function after

cataract extraction. Ophthalmology 1998; 105:1928–1935

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