|Year : 2014 | Volume
| Issue : 2 | Page : 93-98
Comparison of phacoemulsification versus phacotrabeculectomy in the treatment of patients with chronic angle closure glaucoma and concomitant cataract
Chandrima Paul1, Subhrangshu Sengupta1, Ajoy Paul2
1 Regional Institute of Ophthalmology, Kolkata, West Bengal, India
2 B. B. Eye Foundation, Kolkata, West Bengal, India
|Date of Submission||19-Jun-2013|
|Date of Acceptance||05-Dec-2013|
|Date of Web Publication||11-Apr-2014|
B. B. Eye Foundation, 2/5, Sarat Bose Road, Sukhsagar, Kolkata - 700 020, West Bengal
Source of Support: None, Conflict of Interest: None
Aims: Whether phacoemulsification or phacotrabeculectomy (with adjunctive mitomycin C) is the surgery of choice in eyes with chronic angle closure glaucoma (CACG) with concomitant cataract. Settings and Design: Prospective comparative case series. Materials and Methods: Patients with CACG and cataract were randomized into two groups, comparing phacoemulsification (Group A) versus combined phacotrabeculectomy with mitomycin C (Group B). Group A had 60 eyes of medically controlled CACG with cataract and 58 eyes of medically uncontrolled CACG with cataract. Group B had 53 eyes of medically controlled CACG with cataract and 61 eyes of medically uncontrolled CACG with cataract. The two groups had identical study designs. All patients were reviewed 3-monthly for 2 years after surgery. The primary outcome measure was to compare the surgical complications of phacoemulsification versus phacotrabeculectomy and the secondary outcome measures were intraocular pressure (IOP) control and disease progression in the two groups. Statistical analysis used: Fisher's exact test and chi-square test. Results: There was no statistically significant difference in IOP control, glaucomatous progression, or final visual acuity, during the 24-month follow-up, between two groups. In Group A, 5 (4.2%) of 118 eyes reported four surgical complications while in Group B, 18 (15.8%) of 114 eyes had 16 surgical complications. The difference in the proportion of eyes with one or more surgical complications between the two groups was statistically significant [P = 0.003, 95% confidence interval (CI)*]. In addition to this the risk of surgical complication with phacotrabeculectomy was significantly higher when compared to phacoemulsification [3.73 (P = 0.003, 95% CI, 1.43-9.70)]*. Conclusions: Postsurgical complications were more frequently seen after phacotrabeculectomy. However, the data did not reveal statistically significant differences in IOP control, visual acuity, or disease progression between both groups.
Keywords: Adjunctive mitomycin C, CACG, cataract, disease progression, IOP control, phacoemulsification, phacotrabeculectomy, surgical complications
|How to cite this article:|
Paul C, Sengupta S, Paul A. Comparison of phacoemulsification versus phacotrabeculectomy in the treatment of patients with chronic angle closure glaucoma and concomitant cataract. J Clin Ophthalmol Res 2014;2:93-8
|How to cite this URL:|
Paul C, Sengupta S, Paul A. Comparison of phacoemulsification versus phacotrabeculectomy in the treatment of patients with chronic angle closure glaucoma and concomitant cataract. J Clin Ophthalmol Res [serial online] 2014 [cited 2019 Jun 25];2:93-8. Available from: http://www.jcor.in/text.asp?2014/2/2/93/130538
In recent years, evidence that cataract extraction alone results in significant lowering of intraocular pressure (IOP) in chronic angle closure glaucoma (CACG) eyes has accumulated. ,,,,,,
A few previous studies have reported the apparent IOP-lowering effect of cataract extraction alone by phacoemulsification in CACG eyes. ,,,, Therefore, cataract extraction alone for the treatment of CACG with co existing cataract is today a subject of arguable discussion.
Two randomized controlled trials compared the efficacy in IOP control using phacoemulsification alone versus combined phacotrabeculectomy with adjunctive mitomycin C in eyes with medically controlled  and medically uncontrolled  CACG with coexisting cataract.
The aim of our study was to compare the surgical complications of phacoemulsification versus phacotrabeculectomy (with adjunctive mitomycin C) in eyes with CACG with concomitant cataract.
This study also reviews the IOP reduction and difference in disease progression between the two groups.
| Materials and Methods|| |
Institutional ethics committee approval was obtained for conducting this randomized control trial from August 2010 to July 2012. Subjects with CACG and concomitant cataract, fulfilling the laid down inclusion criteria, were randomized to Group A (phacoemulsification alone) and Group B. The two groups were analyzed based on surgical complications, IOP reduction, and difference in disease progression for a 24-month follow-up period.
The inclusion criteria
Eyes with CACG and coexisting cataract as defined below:
CACG: 180° of angle closure which may be synechial or appositional, segmented or continuous, in the presence of a patent peripheral iridotomy. IOP > 21 mm Hg without IOP-lowering medications or requiring IOP-lowering medications Definition of medically controlled ≤21 mm Hg, with ≤3 topical drugs (combination drugs counted as two drugs). Definition of medically uncontrolled IOP > 21 mm Hg despite maximally tolerated medications, or requiring >3 topical drugs for IOP control (combination drugs counted as two drugs). Visual field loss compatible with glaucoma and/or glaucomatous optic disc changes. (Minimal criteria for glaucomatous visual field defect as per the published standard  are glaucoma hemifield test result outside normal limits, pattern standard deviation with P < 0.05, or a cluster of three or more points in the pattern deviation plot in a single hemifield (superior or inferior) with P < 0.0.05, one of which must have P < 0.01. Any one of the preceding criteria, if repeatable, was considered sufficient evidence of a glaucomatous visual field defect).
Cataract: Presence of nucleus sclerosis, cortical cataract, or subcapsular cataract. Visual field ≤ 20/50 and affecting day to day activities.
One-eyed patients and patients with history of previous intraocular surgery, with the exception of laser peripheral iridotomy and argon laser peripheral iridoplasty. Patients refusing either cataract extraction or trabeculectomy.
General baseline information for each patient included age, gender, localization of eye undergoing surgery, type of glaucoma, and ocular medication. Preoperatively, all patients received a standard ophthalmic examination including best corrected visual acuity (BCVA) measurement converted to the logarithm of the minimum angle of resolution, IOP measurement using Goldmann applanation tonometry, angle grading by gonioscopy, slit lamp biomicroscopy of the anterior segment, and indirect ophthalmoscopy of the optic nerve head with documentation of size of optic disc, disc cupping, presence of an optic disc notch or splinter hemorrhage, and peripapillary atrophy.
In the phacoemulsification group (Group A), topical pilocarpine hydrochloride was stopped for 1 week prior to phacoemulsification (other eye medications were continued up to and beyond phacoemulsification). Corneal incision was used to preserve conjunctiva for future filtration surgery.
Topical prednisolone acetate, 1%, and topical moxifloxacin were given postoperatively; frequency and duration were dictated by clinical needs. Postoperatively, any glaucoma eye drops was tapered if the mean IOP at two consecutive visits was <21 mm Hg; the order of stopping drugs was the reverse of the order of resuming drugs, that is, adrenergic agonists first, followed by pilocarpine hydrochloride, carbonic anhydrase inhibitors, prostaglandin analogues, and finally β blockers.
In the phacotrabeculectomy with mitomycin C group (Group B) topical pilocarpine hydrochloride was stopped for 1 week prior to phacotrabeculectomy (other eye medications were continued up to the day of phacotrabeculectomy) Double site phacotrabeculectomy was performed. Adjunctive mitomycin C (0.4 mg/mL) was applied to the scleral surface before scleral incision; the standard application duration was 3 min. Topical prednisolone acetate, 1%, and topical moxifloxacin were given postoperatively; frequency and duration were dictated by clinical needs.
The primary outcome measure was surgical complications. The surgical complications are subdivided into intraoperative complications and postoperative complications for further analysis.
Secondary outcome measures included final IOP control and disease progression. Progression based on changes in glaucomatous optic nerve head morphology was confirmed if one or more of the following criteria were fulfilled:
- Appearance of new splinter hemorrhage;
- Increase in vertical cup disc ratio of 0.1 or more observed at two or more separate follow-up visits;
- Appearance of new or extension of old neuroretinal rim notching observed at two or more separate clinic visits; and
- Appearance of new or extension of old nerve fiber layer defects observed at two or more separate clinic visits.
The vertical cup-disc ratio was taken to be the longest vertical cup diameter divided by the longest vertical disc diameter. Progression based on changes in Humphrey Automated Perimetry (Carl Zeiss, USA) was as per the published standard  : The defect was deepened or enlarged if two or more points within or adjacent to an existing scotoma had worsened by at least 10 dB; all progression required confirmation on at least one subsequent field and clinical correlation with no other explanation for deterioration. Progressions of glaucomatous optic nerve head morphology and glaucomatous visual field loss were not counted as surgical complications in this study.
SPSS-18 was used for statistical analysis and a P value of < 0.05 was considered significant. Chi-square test was used for evaluating change in categorical variables and continuous variable like IOP, BCVA, progression in glaucomatous optic neuropathy, and progression in glaucomatous visual field loss were analyzed using Student's t-test.
| Results|| |
A total of 232 CACG eyes with cataract from 232 patients were included. A total of 118 CACG eyes were randomized to receive phacoemulsification alone-Group A, and 114 eyes to combined phacotrabeculectomy with mitomycin C-Group B. Group A (phacoemulsification alone) had 60 eyes of medically controlled CACG with cataract and 58 eyes of medically uncontrolled CACG with cataract, whereas Group B (phacotrabeculectomy with mitomycin C) had 53 eyes of medically controlled CACG with cataract and 61 eyes of medically uncontrolled CACG with cataract.
Demographic characteristics of the patients in the two groups are summarized in [Table 1]. There were no statistically significant differences between the two treatment groups in age, sex ratio, or laterality of recruited eyes (P > 0.05).
The preoperative clinical status of the patients is summarized in [Table 2]. There were no statistically significant differences between the two groups in the preoperative BCVA, preoperative IOP, number of preoperative topical IOP lowering drugs used, preoperative vertical cup-disc ratio, pattern standard deviation in automated perimetry, and proportion of eyes with previous acute angle-closure attack.
All included patients were reviewed every 3 months for a period of 24 months. Outcome measures up to 24 months are reported.
At baseline, the mean IOP was 30.0 ± 5.3 mm Hg (range: 22-39 mmHg) in the phacotrabeculectomy group and 28.3 ± 4.1 mm Hg (range: 23-37 mmHg) in the phacoemulsification group (P = 0.272). One-way analysis of variance for repeated measurements confirmed a significant difference between baseline and follow-up within both treatment groups (P < 0.001). Mean postoperative IOP was 12.5 ± 6.1 mmHg at 1 month, 13.9 ± 6.4 mm Hg at 3 months, 11.9 ± 3.9 mm Hg at 6 months, and 11.7 ± 3.5 mm Hg at 12 months in the phacotrabeculectomy group. Patients in the phacoemulsification group had a mean IOP of 14.3 ± 4.2 mm Hg at 1 month, 13.5 ± 3.9 mm Hg at 3 months, 14.2 ± 4.6 mm Hg at 6 months, and 12.6 ± 2.1 mm Hg at 12 months. Although the extent of IOP reduction was consistently greater in the phacotrabeculectomy group during follow-up, this difference was not statistically significant.
In Group A, 5 (4.2%) of the 118 CACG eyes reported for 4 surgical complications; in contrast to this 18 (15.8%) of the 114 CACG eyes had a total of 16 surgical complications, in Group B. The difference in the proportion of eyes with 1 or more surgical complications between the two groups was statistically significant [P = 0.003, 95% confidence interval (CI)*]. In addition to this the risk of surgical complication with combined phacotrabeculectomy was significantly higher when compared to phacoemulsification alone [3.73 (P = 0.003, 95% CI: 1.43-9.70)]*. There was no statistically significant difference in final or glaucomatous progression during the 24-month follow-up, between two groups.
[Table 3] presents the intraoperative complications in the two groups. A total of 3 of the 118 eyes in the phacoemulsification group (2.5%) had a total of four intraoperative complications, while 6 of the 114 eyes in the combined phacotrabeculectomy group (5.2%) had a total of four intraoperative complications.
[Table 4]a and 4b show the clinical outcomes in the eyes with intraoperative complications in Group A and Group B, respectively.
Comparing the eyes with and without intraoperative complications in the phacoemulsification group. There were no statistically significant differences in preoperative (P = 0.941) and postoperative (P = 0.983) BCVA between eyes with and eyes without intraoperative complications. Intraoperative complications were not associated with progression in glaucomatous optic neuropathy (P = 0.631) or with progression in glaucomatous visual field loss (P = 0.809).
Comparing the eyes with and without intraoperative complications in the combined phacotrabeculectomy group. There were no statistically significant differences in preoperative (P = 0.957) and postoperative (P = 0.813) BCVA between eyes with and eyes without intraoperative complications. Intraoperative complications were not associated with progression in glaucomatous optic neuropathy (P = 0.599) or with progression in glaucomatous visual field loss (P = 0.225).
[Table 5] shows the postoperative complications in the two groups. None of the 118 eyes in the phacoemulsification group had any postoperative complication, while 18 of the 114 eyes in the combined phacotrabeculectomy group (15.7%) had a total of 16 postoperative complications (P = 0.003).
Postoperative complications were not associated with progression in glaucomatous optic neuropathy (P = 0.599) or with progression in glaucomatous visual field loss (P = 0.225) in the combined phacotrabeculectomy group.
At 24 months, the phacoemulsification group had a mean BCVA of 0.76 ± 0.23.
(0.40-1.0), while the combined phacotrabeculectomy group had mean BCVA of 0.79 ± 0.19 (0.40-1.0) (P = 0.898).
Based on our definition of progression of glaucomatous visual field loss, 1 (20%) in the phacoemulsification group had progression of glaucomatous visual field loss at 24 months as compared with 1 (5.6%) in the combined phacotrabeculectomy group (P = 0.517).
| Discussion|| |
It is well-known that cataract surgery alone can provide a reduction of IOP, although the effect is generally small. , IOP reduction after clear corneal phacoemulsification is considered to be a consequence of increased outflow of aqueous humor due to an increased angle width and tensioning of the trabecular meshwork. Shingleton et al.,  found that IOP reduction was maintained 5 years after cataract surgery. In contrast, IOP is often increased in the early postoperative period in glaucomatous eyes after cataract surgery. 
Our study also demonstrated that phacoemulsification in CACG eyes was associated with a higher rate of surgical complications (4.0%) than we would normally expect for phacoemulsification in eyes with cataract alone. Furthermore, approximately 1 in 8 CACG eyes (15.7%) receiving combined phacotrabeculectomy may have 1 or more surgical complications. Although the extent of IOP reduction was consistently greater in the phacotrabeculectomy group during follow-up, this difference was not statistically significant.
Surgical complications are no doubt associated with more clinic visits, more operative time, inconveniences, financial costs to patients and society, and negative emotions for patients and health care professionals. All these should be taken into consideration in addition to the IOP lowering effects of the two procedures when deciding whether to perform combined phacotrabeculectomy or phacoemulsification alone for any patient with CACG. Eyes with CACG pose unique technical challenges to the cataract surgeon. These eyes have characteristically shallow anterior chambers, ,, which may render anterior chamber surgical maneuvers more difficult and risky. Eyes with CACG, especially those with previous episodes of acute angle closure,  often have lower corneal endothelial cell density and are therefore more prone to intraoperative and postoperative corneal edema. Previous acute angle closure and long-term use of topical pilocarpine hydrochloride may also have resulted in atrophic iris, smaller pupils, and posterior synechiae. All these characteristics of CACG eyes render cataract extraction technically more challenging and may increase the risk of surgical complications.
Our study stands apart in standardization from other similar studies in that all phacotrabeculectomy procedures were of double site and augmented with mitomycin C only.
The ultimate goal for any glaucoma intervention is to halt progression of the disease. Glaucomatous progression was not counted as a surgical complication in this study.  But there was no statistically significant difference in the proportion of eyes with progression in glaucomatous optic neuropathy (P = 0.599) or visual field loss (P = 0.225) between the two groups despite the difference in IOP control.
We, therefore, conclude that phacoemulsification alone has significantly fewer surgical complications, especially postoperative complications, than combined phacotrabeculectomy with adjunctive mitomycin C in CACG eyes with coexisting cataract.
| Acknowledgement|| |
The West Bengal University of Health Sciences. DD 36, Salt Lake Sector 1, Kolkata 700 064.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]