ABSTRACT AIM To evaluate the effects of phacoemulsification on intraocular pressure (IOP) and ultrasound biomicroscope (UBM) images of filtering bleb in eyes with cataract and a previous

functioning filtering bleb. METHODS The IOPs and UBM images of filtering bleb of 24 patients (27 eyes) who underwent phacoemulsification after successful trabeculectomy were recorded at each

follow-up examination and at the 12 months after phacoemulsification, respectively. Preoperative IOP and two parameters of the UBM images, including visibility of a route under the scleral

flap and reflectivity inside the bleb were evaluated for an association with postoperative success rate using Kaplan–Meier survival analysis. RESULTS The mean IOP increased 5.50, 3.85, 3.11,

(_P_=0.398, 0.096). An IOP greater than 10 mmHg, a bleb with an invisible route under the scleral flap and stronger intrableb reflectivity before phacoemulsification were associated with

postoperative antiglaucomatous failure (_P_=0.025, 0.000, and 0.000 respectively). CONCLUSIONS Phacoemulsification significantly increased IOP, but had less effect on intrableb features in

UBM image. Eyes with higher IOP, invisible route under scleral flap and stronger intrableb reflectivity in UBM image before phacoemulsification had greater postoperative antiglaucomatous

failure. SIMILAR CONTENT BEING VIEWED BY OTHERS SURGICAL SITE CHARACTERISTICS AFTER CLASS FOLLOWED BY ULTRASOUND BIOMICROSCOPY AND CLINICAL GRADING SCALE: A 2-YEAR FOLLOW-UP Article 02

November 2020 OUTCOMES OF COMBINED PHACOEMULSIFICATION, ANTERIOR VITRECTOMY, AND SCLERECTOMY IN NANOPHTHALMIC EYES WITH GLAUCOMA Article 05 April 2022 GONIOSCOPY-ASSISTED TRANSLUMINAL

TRABECULOTOMY (GATT) COMBINED PHACOEMULSIFICATION SURGERY: OUTCOMES AT A 2-YEAR FOLLOW-UP Article Open access 24 May 2022 INTRODUCTION A well-functioning filtering bleb is a successful

symbol of trabeculectomy. Previous studies mostly focused on the size, height, vascularisation, vessels, and encapsulation of filtering bleb.1, 2 The recent development by Pavlin and

Foster3, 4 of an ultrasound biomicroscope (UBM) makes it possible to observe the internal structure of filtering bleb and to study the relationship between its internal structure and the

control of intraocular pressure (IOP). The present study observed structural changes before and after phacoemulsification in cataract eyes that had undergone trabeculectomy. We evaluated the

effects of phacoemulsification on IOP and internal structure of filtering bleb, and analysed if the features of filtering bleb in UBM image before phacoemulsification could influence the

success rate of trabeculectomy after phacoemulsification. PATIENTS AND METHODS PATIENTS Patients were included who had undergone a previous trabeculectomy and were admitted for planned

phacoemulsification combined intraocular lens implantation between October 2004 and December 2005 at the Tongren Eye Center, Tongren Hospital, Capital University of Medical Science, Beijing,

People's Republic of China. The interval between trabeculectomy and phacoemulsification is longer than six months. The type of glaucoma is primary angle-closure glaucoma or primary

open-angle glaucoma. The Medical Ethics Committee of the Beijing Tongren Hospital had approved the study protocol and all participants had given written informed consent. We evaluated 27

eyes of 24 patients for whom the duration of postoperative follow up was at least 12 months. Among the 27 eyes, 19 (70.4%) were diagnosed as primary angle-closure glaucoma; eight (29.6%)

were primary open-angle glaucoma. No patient required glaucoma medication. The interval between trabeculectomy and phacoemulsification ranged from 11 months to 29 months. Of the 27 eyes,

antifibrosis agent was used in 22 eyes. Before phacoemulsification, IOP (measured by Goldmann tonometry) and filtering bleb ultrasound biomicroscopic image were noted. The IOP before

phacoemulsification ranged from 4.0 to 19.7 mmHg and the mean IOP was 12.5±4.8 mmHg. After phacoemulsification combined intraocular lens (IOL) implantation, patients were examined at 24 h, 1

week, and 1, 3, 6, 12 months. Intraocular pressure was noted at each follow-up visit and filtering bleb ultrasound biomicroscopic image was noted at 12 months after phacoemulsification. We

defined success as the absence of glaucoma medications, bleb needling, or further glaucoma surgery to maintain IOP control after phacoemulsification. PHACOEMULSIFICATION COMBINED IOL

IMPLANTATION All phacoemulsification procedures were performed by the same surgeon. The technique and general protocol were similar for all patients. Phacoemulsification was performed with

all patients under topical anaesthesia. A clear corneal incision was made away from the edge of the filtering bleb with a 3.2 mm keratome. Posterior synechiolysis and/or pupil stretching

were performed as needed. Continuous circular capsulotomy was performed with capsulorhexis forceps. After hydrodissection, the nucleus was removed by phacoemulsification. The cortical

remnants were irrigated and aspirated. A foldable acrylic posterior chamber IOL (AcrySof natural, Alcon laboratories, Fort Worth, TX, USA) was inserted into the capsular bag. Viscoelastic

was removed as much as possible from the eye. The routine postoperative treatment included a combination of dexamethasone and tobramycin six times a day for two weeks and then the dosage was

tapered until the discontinuation after six weeks. ULTRASOUND BIOMICROSCOPY (UBM) Ultrasound biomicroscopy was conducted with the UBM 840 system (Humphrey–Zeiss, San Leandro, CA, USA) at 12

months after phacoemulsification. For our measurements, the ultrasound biomicroscope was set at a 5.0 × 5.0 mm field of view with 80 dB of gain, 5 dB of gain compensation, and a 2.24–3.76 

mm delay. The patients maintained a supine position during the examination. With the aid of an eyecup filled with 1.5% ethylcellulose (Scopisol) and physiologic saline, the probe scanned

over the entire region of the filtering bleb in parallel with the meridian. During the scanning procedure, we evaluated: (1) visibility of a route under the scleral flap and (2) reflectivity

inside the bleb. If a route could be identified under the scleral flap and could be followed along the entire scleral flap, the route was classified as visible. The reflectivity of the bleb

was classified according to its similarity to the scleral reflectivity of the same ultrasound biomicroscopic image and a standard intrableb image for low reflectivity (Figure 1). The image

was classified into type low, medium, and high according to the method of Yamamoto.5 All ultrasound biomicroscopy was conducted by the same researcher and UBM reading was conducted in a

masked fashion. STATISTICAL ANALYSIS Longitudinal comparisons of IOPs were made using the two-tailed Student's _t_-test for paired samples. Comparisons of routes under scleral flap and

reflectivity inside the bleb before and after phacoemulsification were performed using the _χ_2 test. The probability of success after phacoemulsification was estimated with Kaplan–Meier

survival analysis. The distribution of survival rates for preoperative factors was compared with the log-rank test. A statistics programme (SPSS 10.0 for Windows, SPSS Inc., Chicago, IL,

USA) was used for analysis. A _P_-value of 0.05 or less was considered statistically significant. RESULTS The mean IOPs before and after phacoemulsification at each followup interval are

shown in Table 1. The mean IOP before phacoemulsification was 12.5±4.8 mmHg. After phacoemulsification, the mean IOP increased significantly compared with the mean IOP before

phacoemulsification: by 5.5 mmHg on postoperative day 1 (_P_=0.000), by 3.9 mmHg after 1 week (_P_=0.000), by 3.1 mmHg after 1 month (_P_=0.000), by 3.1 mmHg after 3 months (_P_=0.000), by

2.8 mmHg after 6 months (_P_=0.000), by 2.6 mmHg after 12 months (_P_=0.000). Table 2 lists the preoperative and postoperative visibility of the route under the scleral flap. There was no

statistically significant difference in visibility of the route under the scleral flap before and after phacoemulsification (_P_=0.398). Table 3 lists the preoperative and postoperative

reflectivity inside the bleb. There was no statistically significant difference in reflectivity inside the bleb before and after phacoemulsification (_P_=0.096). We defined success as the

absence of glaucoma medications, bleb needling, or further glaucoma surgery to maintain IOP control after phacoemulsification. The Kaplan–Meier success rate after phacoemulsification was

77.8% at 12 months. The IOP before phacoemulsification had a statistically significant effect on the possibility of failure. A preoperative IOP greater than 10 mmHg was associated with the

need for glaucoma medications or bleb needling after phacoemulsification (_P_=0.025). Preoperative visibility of the route under the scleral flap and reflectivity inside the bleb had effects

on the propensity for failure (_P_=0.000, _P_=0.000, respectively). Invisible route under the scleral flap and/or higher reflectivity inside the bleb before phacoemulsification were

associated with antiglaucomatous failure after phacoemulsification (Table 4). DISCUSSION There are many studies on IOP changes after phacoemulsification in glaucoma-filtered eyes, ranging

from a decrease of 0.8 mmHg to an increase of 6.6 mmHg (follow up ranging from 8 to 70 months).2, 6, 7, 8, 9 Rebolleda _et al_6 reported that there is a mean IOP increase of 2.04 mmHg 12

months after phacoemulsification. Klink _et al_2 found a statistically significant mean IOP increase of 2.05 mmHg one year after phacoemulsification. Our study showed a mean IOP increase of

2.6 mmHg 12 months after phacoemulsification, and it is slightly higher than that in above mentioned studies. Ultrasound biomicroscopy is an important tool to observe internal structure of

filtering bleb. Visibility of the route under the scleral flap and reflectivity inside the bleb are two important aspects, which evaluate the UBM image of filtering bleb. Some studies5, 10

showed that the features of the ultrasound biomicroscopic image were significantly associated with filtering bleb function. Visibility of a route under the scleral flap and reflectivity

inside the bleb were highly associated with IOP control. The invisible route under scleral flap and the high-reflective bleb were found mostly in eyes with poor IOP control. The studies by

Avitabile _et al_11, 12 showed that blebs with lower reflectivity and a visible route under the scleral flap had a lower IOP. They believed that UBM could be a useful method to study and

explain the mechanisms of filtering structures and, together with IOP control, to evaluate the bleb function. In the current study, we found that before phacoemulsification the route under

scleral flap is visible and reflectivity inside bleb is low in all the 11 eyes with IOP less than 10 mmHg. But in 16 eyes with IOP more than 10 mmHg, visible route under scleral flap was

found in eight eyes and low reflectivity inside bleb was found in four eyes. These findings were in accordance with that by Yamamoto _et al._5 The structures of filtering bleb in UBM images

before and after phacoemulsification were both observed and compared in our study. Though the visible route under scleral flap became invisible or became narrower and the low reflectivity

inside the bleb became high in most eyes, the changes before and after phacoemulsification did not have a statistical significance. We think the techniques of phacoemulsification, which is

minimally invasive now, have less effect on the route under the scleral flap and reflectivity inside the bleb. Because filtering bleb has its own natural evolutional course, so larger sample

size and control study are needed to specify the features of filtering bleb before and after phacoemulsification. Many preoperative and perioperative factors, including preoperative IOP,

time from trabeculectomy, intraoperative iris manipulation, antimetabolism use and so on were evaluated for an association with postoperative success in some previous studies.6, 7, 13, 14

But the factors such as visibility of the route under the scleral flap and reflectivity inside the bleb in UBM image before phacoemulsification were not evaluated to estimate postoperative

success rate before. In our study, eyes with an IOP greater than 10 mmHg before phacoemulsification more often required medication to control IOP than eyes with an IOP of 10 mmHg or less.

Our outcome were in accordance well with studies by several authors.6, 13 Eyes with visible route under scleral flap before phacoemulsification had higher success rate at 12 months after

phacoemulsification than eyes with invisible route under scleral flap (_P_=0.000). Eyes with lower reflectivity inside bleb before phacoemulsification had less failure rate at 12 months

after phacoemulsification than eyes with higher reflectivity inside bleb (_P_=0.000). The success of trabeculectomy after phacoemulsification was highly correlated with IOP level, visibility

of the route under the scleral flap and reflectivity inside the bleb in UBM image before phacoemulsification. Our results indicate that performing phacoemulsification after trabeculectomy

may increase the IOP. Though phacoemulsification, which has the tendency to become the minimally invasive operation, has less effect on the route under the scleral flap and reflectivity

inside the bleb, we can estimate the fate of glaucoma after phacoemulsification according to features of filtering bleb before phacoemulsification. In order to observe the long-term effects

of phacoemulsification on filtering bleb, a longer follow-up is needed. REFERENCES * Picht G, Grehn F . Classification of filtering blebs in trabeculectomy: biomicroscopy and functionality.

_Curr Opin Ophthalmol_ 1998; 9: 2–8. Article  CAS  Google Scholar  * Klink J, Schmitz B, Lieb WE, Klink T, Grein HJ, Sold-Darseff J _et al_. Filtering bleb function after clear cornea

phacoemulsification: a prospective study. _Br J Ophthalmol_ 2005; 89: 597–601. Article  CAS  Google Scholar  * Pavlin CJ, Harasiewicz K, Sherar MD, Foster FS . Clinical use of ultrasound

biomicroscopy. _Ophthalmology_ 1991; 98: 287–295. Article  CAS  Google Scholar  * Pavlin CJ, Foster FS . _Ultrasound Biomicroscopy of the Eye_. Springer–Verlag: New York, 1995. Book  Google

Scholar  * Yamamoto T, Sakuma T, Kitazawa Y . An ultrasound biomicroscopic study of filtering blebs after mitomycin C trabeculectomy. _Ophthalmology_ 1995; 102: 1770–1776. Article  CAS 

Google Scholar  * Rebolleda G, Munoz-Negrete FJ . Phacoemulsification in eyes with functioning filtering blebs: a prospective study. _Ophthalmology_ 2002; 109: 2248–2255. Article  Google

Scholar  * Chen PP, Weaver YK, Budenz DL, Feuer WJ, Parrish RK II . Trabeculectomy function after cataract extraction. _Ophthalmology_ 1998; 105: 1928–1935. Article  CAS  Google Scholar  *

Wygnanski-Jaffe T, Barak A, Melamed S, Glovinsky Y . Intraocular pressure increments after cataract extraction in glaucomatous eyes with functioning filtering blebs. _Ophthalmic Surg Lasers_

1997; 28: 657–661. CAS  PubMed  Google Scholar  * Derbolav A, Vass C, Menapace R, Schmetterer K, Wedrich A . Long-term effect of phacoemulsification on intraocular pressure after

trabeculectomy. _J Cataract Refract Surg_ 2002; 28: 425–430. Article  Google Scholar  * Jinza K, Saika S, Kin K, Ohnishi Y . Relationship between formation of a filtering bleb and an

intrascleral aqueous drainage route after trabeculectomy: evaluation using ultrasound biomicroscopy. _Ophthalmic Res_ 2000; 32: 240–243. Article  CAS  Google Scholar  * Avitabile T, Russo V,

Uva MG, Marino A, Castiglione F, Reibaldi A . Ultrasound-biomicroscopic evaluation of filtering blebs after laser suture lysis trabeculectomy. _Ophthalmologica_ 1998; 212 (Suppl 1): 17–21.

Article  Google Scholar  * Avitabile T, Uva MG, Russo V, Ott JP, Paulick B, Reibaldi A . Evaluation of the filtering bleb using ultrasound biomicroscopy. _Klin Monatsbl Augenheilkd_ 1998;

212: 101–105. Article  CAS  Google Scholar  * The advanced glaucoma intervention study (AGIS): 7. The relationship between control of intraocular pressure and visual field deterioration. The

AGIS Investigators. _Am J Ophthalmol_ 2000; 130: 429–440. Article  Google Scholar  * Crichton AC, Kirker AW . Intraocular pressure and medication control after clear corneal

phacoemulsification and AcrySof posterior chamber intraocular lens implantation in patients with filtering blebs. _J Glaucoma_ 2001; 10: 38–46. Article  CAS  Google Scholar  Download

references AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Tongren Eye Center, Tongren Hospital, Capital University of Medical Science, Beijing, People's Republic of China X Wang, H

Zhang, S Li & N Wang Authors * X Wang View author publications You can also search for this author inPubMed Google Scholar * H Zhang View author publications You can also search for this

author inPubMed Google Scholar * S Li View author publications You can also search for this author inPubMed Google Scholar * N Wang View author publications You can also search for this

author inPubMed Google Scholar CORRESPONDING AUTHOR Correspondence to N Wang. RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Wang, X., Zhang, H., Li, S.

_et al._ The effects of phacoemulsification on intraocular pressure and ultrasound biomicroscopic image of filtering bleb in eyes with cataract and functioning filtering blebs. _Eye_ 23,

112–116 (2009). https://doi.org/10.1038/sj.eye.6702981 Download citation * Received: 11 March 2007 * Revised: 06 July 2007 * Accepted: 06 July 2007 * Published: 12 October 2007 * Issue Date:

January 2009 * DOI: https://doi.org/10.1038/sj.eye.6702981 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a

shareable link is not currently available for this article. Copy to clipboard Provided by the Springer Nature SharedIt content-sharing initiative KEYWORDS * phacoemulsification * intraocular

pressure * ultrasound biomicroscopy * filtering bleb