|Year : 2016 | Volume
| Issue : 1 | Page : 27-32
Evaluation of visual and surgical outcomes after phacotrabeculectomy in patients with primary open angle and primary closed angle glaucomas
CB Manju, Amita Verghese, Verghese Joseph
Glaucoma Clinic, Eye Microsurgery and Laser Centre, Tiruvalla, Kerala, India
|Date of Web Publication||11-Nov-2016|
C B Manju
Eye Microsurgery and Laser Centre, Tiruvalla - 689 101, Kerala
Source of Support: None, Conflict of Interest: None
Introduction: Both glaucoma and cataract often coexist in the elderly population. In these patients, a combined surgery has advantages such as improved vision and intraocular pressure (IOP) reduction in a single sitting.
Aim: The aim of this study was to evaluate the effectiveness and safety of the combined procedure in patients with coexisting cataract and primary open or closed-angle glaucoma.
Materials and Methods: A prospective study was conducted which included 20 eyes of 17 patients planned for phacotrabeculectomy procedure. Preoperative evaluation included detailed ocular examination for the grade of cataract, glaucoma evaluation, and exclusion of ocular comorbidities. A superior trabeculectomy with mitomycin C and temporal phacoemulsification with in the bag intraocular lens implantation was performed. Postoperatively, improvement in the best corrected visual acuity, IOP control, and reduction in the number of antiglaucoma medications was evaluated. Patients were followed for a 6-month period.
Results: Postoperatively, all the patients had significant improvement in best corrected visual acuity (P < 0.0001) and significant reduction in IOP. The usage of antiglaucoma medication was lower (P < 0.0001) and 85% percent (17 eyes) had no complications.
Conclusion: Combined phacoemulsification and trabeculectomy is an effective and safe procedure to provide good visual acuity and control of intraocular pressure at the same time.
Keywords: Glaucoma; intraocular pressure; phacotrabeculectomy; visual acuity.
|How to cite this article:|
Manju C B, Verghese A, Joseph V. Evaluation of visual and surgical outcomes after phacotrabeculectomy in patients with primary open angle and primary closed angle glaucomas. Kerala J Ophthalmol 2016;28:27-32
|How to cite this URL:|
Manju C B, Verghese A, Joseph V. Evaluation of visual and surgical outcomes after phacotrabeculectomy in patients with primary open angle and primary closed angle glaucomas. Kerala J Ophthalmol [serial online] 2016 [cited 2019 Jul 23];28:27-32. Available from: http://www.kjophthal.com/text.asp?2016/28/1/27/193875
| Introduction|| |
Glaucoma and cataract often coexist in the elderly population as the prevalence of both increases with age. Also presence of glaucoma increases the risk of cataract. Following cataract extraction, intraocular pressure (IOP) is known to lower by 2–4 mmHg, especially in patients with chronic angle closure glaucoma than in patients with open angles. This is because once the cataractous lens is removed, the iris moves back, resulting in opening of iridocorneal angle and allowing the trabecular meshwork to expand and attain better outflow. However, this reduction may not be enough to prevent damage due to glaucoma progression. In addition, in patients with advanced glaucoma, the postoperative IOP spike following cataract surgery can have a deleterious effect than in a normal eye.
Glaucoma surgery is indicated in patients who fail to respond to maximally tolerated medical therapy or who continue to have progressive optic nerve damage in spite of medical control. Glaucoma surgery alone can significantly increase the risk of development of cataract. Cataract surgery following trabeculectomy can result in bleb failure especially within the first 6 months.
Considering the above facts, in patients with visually significant cataract and glaucoma requiring surgical correction, a combined technique of surgery is considered as a standard surgical method of management. The objective of phacotrabeculectomy is to achieve an adequate long-term control of IOP, obtain an optimal visual rehabilitation, reduce antiglaucoma medications, and improve the quality of life of the patient.
The aim of the present study was to evaluate the effectiveness and safety of combined phacotrabeculectomy in patients with coexisting cataract and primary open angle or primary angle closure glaucoma.
The outcome measures included visual recovery, IOP control, reduction in topical antiglaucoma medications, and the safety of the procedure.
| Materials and Methods|| |
A prospective study was conducted at the glaucoma clinic of our hospital on patients with primary open-angle or closed-angle glaucoma with senile cataract planned for combined surgery. All patients had registered for the procedure during a 1-year period from November 2013 to October 2014. All patients provided an informed consent for the surgery, and ethical clearance was obtained from ethical committee for conducting the study.
Patients with visually significant cataract of grade II to IV (LOC III classification) and either primary open angle or primary angle closure glaucoma were included in the study, considering that IOP control on current treatment was not adequate, three or more medications were needed to achieve target IOP, and there was moderate-to-severe glaucomatous damage of the disc and visual fields. Compliance to medical therapy, difficulty in access to medical care facilities, and effect of disease on quality of life of the patient were additional factors considered for including the patient in the study.
Patients with congenital and secondary glaucoma, pseudoexfoliation syndrome, neovascular or steroid-induced glaucoma, patients with advanced glaucomatous optic neuropathy, and patients with complicated cataract were not included. Patients with history of previous intraocular surgeries or trauma, retinal disease contributing to decreased vision, rigid pupil, and low endothelial cell density, and those with conjunctival inflammation due to medical therapy were also excluded.
A detailed ocular and medical history was recorded and a note was made regarding the number of antiglaucoma medications the patient was using. A standard ophthalmic examination was carried out, which included best corrected visual acuity (BCVA) using Logmar chart, corrected IOP using Goldmann applanation tonometer, pachymetry, and gonioscopy were also performed.
Slit lamp examination was done for the anterior segment details related to glaucoma diagnosis, assessment of grade of cataract, and exclusion of pseudoexfoliation syndrome. Fundus examination with 90D lens and direct and indirect ophthalmoscope was done to examine the optic nerve head for the cup-disc ratio, retinal nerve fibre layer (RNFL) defects, and presence of associated retinal comorbidities. Humphrey field analyzer (HFA) 24-2 full threshold perimetry was used to assess visual field defects. Optical coherence tomography (OCT) was performed to measure cup-disc ratio and determine nerve fiber loss, as well as to rule out any macular problem contributing to vision loss.
Surgery was performed by the same surgeon following standard techniques. Trabeculectomy was performed superiorly and phacoemulsification was done via the temporal approach. Preoperatively, pupils were dilated using tropicamide eye drops 0.8%, phenylephrine hydrochloride 5.0%, and cyclopentolate hydrochloride 1% eye drops. The procedure was performed under peribulbar block.
The eye ball was immobilized with 4-0 nylon suture beneath the tendon of superior rectus muscle at 12 o'clock position. Fornix-based conjunctival flap of 6–7 mm was made at limbus and extended 6–7 mm on either side and superiorly with Westcott's scissors. Bleeders were cauterized using bipolar cautery. A 4 mm × 4 mm triangular limbal-based partial thickness scleral flap was marked with a diamond knife and dissected with a crescent knife up to clear cornea. A sponge soaked with 0.2 mg/ml mitomycin-C placed under the scleral flap for 2 minutes followed by copious wash with balanced salt solution. The rest of the trabeculectomy procedure was completed after phacoemulsification.
The surgeon shifted position to the temporal side of the eye. Side ports were made and viscoelastic injected into the anterior chamber. A clear corneal incision was made temporally with a 2.8 mm keratome. Lens nucleus was removed by phacoemulsification after 5 mm radius curvilinear capsulorrhexis. Remaining cortex was removed with bimanual irrigation and aspiration, followed by intraocular implant (IOL) placement in the bag.
Completion of trabeculectomy
Returning back to the superior position, a sclerotomy was made under the scleral flap at the limbus using diamond knife. The inner posterior lip of scleral tunnel was punched with a Kelly's Descement's punch to make a trabeculectomy window, followed by a peripheral basal iridectomy. Scleral flap was closed with a 10-0 nylon suture at its apex. Suture tension was carefully adjusted to maintain anterior chamber depth and to prevent over filtration.
The conjunctival flap was then sutured using 8-0 vicryl and anchored to cornea by 10-0 nylon to prevent bleb leakage. Viscoelastic was completely removed from the anterior chamber, and the chamber was reformed with balanced salt solution. Main wound and side ports were hydrated to keep a well-maintained anterior chamber and a firm eye ball.
Postoperatively, the patients were examined on day 1, 1 week, 1 month, and 3 months, and then every 3 months if the postoperative period was uneventful and visual acuity and IOP was stabilized. The maximum follow-up was up to 6 months.
Postoperatively, patients were on prednisolone acetate 1% eye drops every 2 hourly for 1 week followed by betamethasone sodium Phosphate 0.1% eye drops 4 times a day tapered rapidly over 1 month. Topical antibiotic drops and nonsteroidal anti-inflammatory drops 3 times a day for 1 month along with cyclopentolate hydrochloride 1% at bed time were also instilled. Postoperative assessment included BCVA, IOP, function and character of filtering bleb, and postsurgical complications.
| Results|| |
Twenty eyes of 17 patients underwent phacoemulsification with posterior chamber intraocular implantation and trabeculectomy with mitomycin C. [Table 1] presents all baseline characteristics of eyes included in the study. The mean age of was 68.05 years (range: 50–79). The mean preoperative visual acuity was 0.50 log MAR (range: 0.2–1.00), the average corrected preoperative IOP was 17.6 mmHg (range: 9–30 mmHg) and patients were on a mean of 2.35 (range: 1–4) antiglaucoma medications.
Improvement in best corrected visual acuity
Postoperatively, visual acuity improved in all the patients. Bivariate analysis by Chi-square test showed significant improvement in BCVA with a P < 0.0001 [Table 2]. [Figure 1] depicts that visual acuity consistently improved till 3 months postoperatively and remained stable till the last follow-up.
|Table 2: Comparison between preoperative and postoperative best corrected visual acuity|
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|Figure 1: Number of Lines improvement in BCVA at each post operative visit|
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Postoperative reduction in intraocular pressure
The mean IOP reduction at 6 months was 5.4 mmHg from preoperative mean IOP of 17.6 mmHg. Postoperative corrected IOP at each visit averaged to 13.3 mmHg, 13.4 mmHg, and 12.2 mmHg, respectively, at 1, 3, and 6-month follow-up [Table 3]. At each follow-up, IOP was statistically lower than the preoperative levels and remained stable till the 6-month follow up (chi square = 17.57 and P < 0.0405) [Figure 2].
|Table 3: Mean preoperative intraocular pressure at each postoperative visit|
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Reduction in antiglaucoma medications
Preoperatively, patients were on an average of 2.35 antiglaucoma medications. At postoperative 1 month, none required any antiglaucoma medication, and at 6 months, 3 patients needed one antiglaucoma medication [Table 4].
|Table 4: Comparison of preoperative and postoperative glaucoma medications|
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Seventeen eyes (85%) did not develop any postoperative complications. The only complications that occurred were hypotony with choroidal effusion. None of the eyes developed hypotonic maculopathy.
Functioning of bleb
Among the operated 20 eyes, 14 (70%) had a well-functioning bleb at the end of 6 months, 4 (20%) had diffuse bleb, and 2 (10%) had flat bleb. The flattening was not significant from the current study (P = 0.7119).
| Discussion|| |
Today's advanced phacoemulsification techniques and improved glaucoma surgery along with use of antifibrotic agents facilitate more efficient combined surgery procedures. Microincision and foldable IOL implantation reduces the postoperative inflammatory response, and use of antifibrotic agents along with trabeculectomy enhance the success of trabeculectomy bleb.
Phacoemulsification procedure per say has an advantage for postoperative better outcome because there is no conjunctival dissection and a lower grade of ocular inflammation, which would decrease wound healing stimuli as compared to other methods of cataract surgery.,,
In our study, we followed-up 20 eyes of 17 patients who underwent combined phacoemulsification and trabeculectomy procedure with mitomycin C to assess the safety and efficacy of the procedure. The study included 13 eyes with primary open angle glaucoma and seven with primary angle closure glaucoma.
Not many similar studies are reported in literature.,,,, Friedman et al. and Chen et al. reported a strong evidence for better long-term control of IOP with combined glaucoma and cataract operation compared with cataract extraction alone. Munden and Alward  in their study concluded that the glaucoma triple procedure with mitomycin C as an adjunct appears to be safe and effective technique for treating selected cases.
Zhu et al. recommended triple surgery even when the cataract is not too mature or premature. In the present study, we found out that there was significant improvement in BCVA at 1-month postoperative follow-up and it improved further on subsequent follow ups (P < 0.0001). All eyes recovered a BCVA of 0.30 or more and 90% of eyes had BCVA of 0.00–0.20 with near vision of N6. There was an average improvement of an average of 3.5, 3.75, and 3.80 Logmar lines of visual acuity at each follow-up visit.
Four eyes did not need any spectacle correction for distant vision, 2 eyes needed a spherical correction whereas the rest 14 required astigmatic correction. Belyea et al. followed up 29 consecutive eyes of 26 patients and found a significant improvement in visual acuity by at least 4.5 lines of Snellen visual acuity.
All eyes in our study had good and consistent IOP control till the last follow up at 6 months postoperatively. The postoperative IOP was significantly lower than the preoperative levels. The average reduction in IOP at 1, 3, and 6 months, was 4.5, 3.85, and 5.05 mmHg, respectively.
Rockwood et al. reported 5.5 mmHg mean IOP reduction at 1 year and 6 months follow up, and Belyea et al. reported average IOP reduction of 6.5 mmHg at 1 year follow up, which was comparatively better than that reported by us at 6-month follow up.
Antifibrotic agents are known to reduce and act as adjuvant to trabeculectomy., Jamphal  in his review concluded that mitomycin C in combined surgery reduced IOP by 2–4 mm of Hg. In our study, we used mitomycin C as adjuvant in all our cases.
Postoperatively, the use of antiglaucoma medications reduced significantly (P < 0.0001). Seventeen eyes (85%) did not need antiglaucoma drops postoperatively. Three eyes (15%) required a single topical drug for better control of IOP after the 3-month follow up.
Preoperatively, the average antiglaucoma medications being used was 2.35, which reduced to 0.15 in our study (Chi-square = 63.33, P < 0.0001). Rockwood  reported a reduction of glaucoma medication from 2.0 to 0.9 medications, and Zhu  reported significant (P < 0.05) reduction in the use of glaucoma medications after combined surgery. In a study conducted by Steven et al., 85% of the patients were maintained on fewer medications than preoperative period and only 15% required more medication than preoperative period.
Fourteen (70%) eyes had well-formed functioning bleb at the end of 6 months. Four (20%) had diffuse bleb and 2 (10%) had flat bleb at 6 months. Even those with a flat or diffuse bleb, the IOP was low or controlled significantly. Therefore, the bleb morphology cannot be considered as criteria for functioning of trabeculectomy. Similar observations have been made by Steven  and Munden. Steven found that, in spite of good control of IOP at 12 months postoperatively, only 12% had a good functioning bleb, and Munden  reported that only 66.7% of the successful eyes had a functional filtering bleb.
Overall, incidence of intraoperative and postoperative complications was significantly low in our study. Seventeen eyes (85%) did not have any postoperative complications. Three eyes had hypotony with choroidal effusion in the immediate postoperative period. In 2 eyes, there was wound leak for which bleb revision and re-suturing was performed to prevent wound leak. The third had shallow anterior chamber due to hypotony and choroidal effusion, which was managed by air injection into the anterior chamber. All 3 eyes recovered within a period of 1 week and had a visual acuity of 0.30 or better and IOP of 8 mmHg or more. Only 1 eye had posterior capsular opacification at 3 month follow-up, however, his visual acuity improved after Nd:YAG capsulotomy.
Many major complications reported in literature are flat or shallow anterior chamber, hyphema, sterile or infective endophthalmitis, hypotonic maculopathy,, bleb leakage and late bleb infection, cystoids macular edema, capsular opacification, uncontrolled IOP, and displaced IOL. Compared to the previously mentioned studies, our patients had significantly minimal complications and none had complications such as uncontrolled IOP, hypotonic maculopathy, bleb leakage, late bleb infection, cystoid macular edema, or endophthalmitis.
Perimetry was done at 6 months postoperatively in 18 eyes. Twelve eyes showed improvement in PSD values and 6 eyes had mild worsening of PSD values. The change was not statistically significant (P = 0.154 in paired t-test). The improvement could be due to improved performance of the patient after cataract removal.
| Conclusion|| |
Our technique of combined surgery proved to be a safe and efficient approach for surgical management of patients with cataract and open or closed angle glaucomas. Postoperative visual rehabilitation was excellent and IOP control was statistically significant with low dependency on antiglaucoma medications.
However, our findings are preliminary and long-term follow-up is necessary to establish the actual effectiveness of combined surgeries.
We did not have a second group for comparison; long follow-ups are needed to further establish the efficacy of the procedure.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]