ORIGINAL ARTICLE  
Trabeculectomy in Congenital Glaucoma;  
Experience in Helpers Eye Hospital Quetta  
Mahtab Mengal1, M. Afzal Khan2, Aimal Khan3, Manzoor Ahmed4, Rabia Khawar Chaudhry5  
Nasar Qamar Khan6  
1-4Bolan University of Medical and Health Sciences (BUMHS), Quetta, 5-6Jinnah Postgraduate Medical Centre  
(JPMC), Karachi  
ABSTRACT  
Purpose: To evaluate outcomes of trabeculectomy in terms of IOP control and its safety in terms of per-  
operative and post-operative complications in Primary Congenital Glaucoma.  
Study Design: Interventional Case-Series.  
Place and Duration of Study: Helpers Eye Hospital, Quetta, from June 2017 to December 2018.  
Material and Methods: Thirty eyes of 17 patients were included in this case series after diagnosis of primary  
congenital glaucoma. Patients with secondary congenital glaucoma due to trauma, surgery, inflammation, Sturge  
Weber Syndrome, Neurofibromatosis, cataract, uveitis, aphakia and pseudophakia were excluded from the study.  
Informed consent was taken from parents. Examination under anesthesia was done before surgery to record  
preoperative IOP, corneal diameter and anterior and posterior segment abnormalities. Primary trabeculectomy  
was done. Post-operative IOP and corneal diameter was recorded at 1st, 3rd and 6th month and every 6 months  
thereafter under general anesthesia. IOP at 12th month of surgery was the final outcome which was considered  
significant if IOP was less than 21 mm Hg with stable corneal diameters.  
Results: Mean preoperative IOP was 25.8 mm Hg. Twenty-three (76.66%) eyes out of 30 eyes were considered  
successful with mean IOP of 15.3 mm Hg at last follow-up while 7 (23.33%) cases of failure were observed with  
postoperative mean IOP of 27.71 mm Hg. These patients underwent additional surgeries to control IOP.  
Hyphema was the only complication observed in this study. Postoperative cataract developed in 5 eyes.  
Conclusion: Primary trabeculectomy is an effective operation and safe surgery for primary congenital glaucoma.  
Key Words: Primary congenital glaucoma, intra-ocular pressure, trabeculectomy.  
How to Cite this Article: Mengal M, Khan MA, Khan A, Ahmed M, Chaudhry RK, Khan NQ. Outcomes of  
Trabeculectomy in Congenital Glaucoma; Experience in Helpers Eye Hospital Quetta. Pak J Ophthalmol. 2020;  
36 (3): 253-257.  
Doi: 10.36351/pjo.v36i3.1043  
accounts for 2.5-15% of all documented cases of  
INTRODUCTION  
The commonest type of glaucoma in pediatric age  
blindness in children1,2 and occurs without any other  
ocular or systemic abnormalities. It is caused by  
group is primary congenital glaucoma (PCG) which  
abnormal development of the angle of anterior  
chamber2, which leads to raised IOP, subsequently,  
Correspondence to: Mahtab Mengal  
Bolan University of Medical and Health Sciences  
(BUMHS), Quetta.  
opaque cornea, enlargement of eyeball, optic disc  
damage and permanent loss of vision. Timely  
treatment can prevent permanent loss of vision and  
lifetime disability1.  
Email: mengalmahtab@yahoo.com  
The incidence of PCG varies in different ethnic  
populations. In developed western countries it is  
Received: April 17, 2020  
Accepted: May 4, 2020  
Revised: May 4, 2020  
Pakistan Journal of Ophthalmology, 2020, Vol. 36 (3): 253-257  
253  
Mahtab Mengal, et al  
approximately 1 in 10,000 to 70,000 births1,3. In Saudi  
Arabia, Southern India, Slovakia, it is between 1:1,250  
and 1:33004. In Pakistani pediatric population  
incidence of PCG is nine times higher than that in  
Caucasians5. In Chinese population PCG constitutes  
Cup disc ratio > 0.3.  
Corneal edema.  
Age: Patients under 5 years.  
Either gender.  
5.1%6 The higher rate of consanguinity is considered  
.
Exclusion criteria for this study were; patients  
as the cause of this higher incidence of PCG3,7.  
having raised IOP due to secondary causes, for  
example, history of ocular trauma, ocular surgery,  
inflammation,  
Neurofibromatosis, cataract, uveitic glaucoma, aphakia  
and pseudophakia.  
The ultimate aim of treatment in congenital  
glaucoma is to control IOP to restore vision7. The  
treatment of choice is surgical because medical  
therapy poorly controls the IOP in congenital  
glaucoma1. The preferred surgical options are  
Goniotomy, Trabeculotomy, Trabeculectomy, or  
combined Trabeculotomy-Trabeculectomy with or  
without Mitomycin C8,9.  
Sturge  
Weber  
syndrome,  
Total sample size was 30, which was calculated by  
non-probability consecutive sample technique using;  
Confidence level = 95%  
Absolute precision[d] = 0.10  
Anticipated population proportion [p] = 92.3%24,25,27  
According to previous reports success rate of  
Goniotomy and Trabeculotomy is 81 – 90% in western  
countries due to early presentations of PCG while low  
success rate in Middle East10,11. In another report, 25%  
success rate of Goniotomy was reported in PCG8. In  
developing countries, PCG patients present late with  
severe disease and cloudy cornea, in which Goniotomy  
is not possible12,13. In such situations, trabeculectomy  
is the preferred procedure. Different studies document  
the success rate of primary Trabeculectomy varying  
from 54% to 92.3% in PCG11,14,15. Another researcher  
reported 75% success rate of primary trabeculectomy  
in PCG16.  
.
Examination under anesthesia (EUA) was done in  
every patient. During EUA IOP, corneal diameter,  
anterior segment examination, fundoscopy for optic  
disc assessment, B-scan, A-scan for axial length  
measurement and retinoscopy for refractive error (if  
media was clear) were recorded.  
Surgery was performed by one surgeon. Under  
general anaesthesia and aseptic technique, corneal stay  
suture was applied at 12 ‘O’clock using 6 – 0 vicryl  
(polyglactin) suture. A fornix-based conjunctival flap  
was lifted and cauterization of superficial scleral  
vessels was done to secure hemostasis. A partial  
thickness scleral flap of 4 × 4ꢀmm size was dissected  
upto about 1ꢀmm of clear cornea. The inner  
trabeculectomy groove of 2 × 2ꢀmm was made. The  
inner block of tissue comprised of trabecular  
meshwork and scleral spur. Peripheral Iridectomy (PI)  
was done. The partial thickness scleral flap was  
sutured with 10–0 nylon. The conjunctival flap was  
closed with 8–0 continuous watertight sutures and at  
the end of the surgery, the patency of the PI and scleral  
flap was checked and watertight conjunctival bleb was  
assessed. Combination of antibiotic and steroid  
(Dexamethasone and gentamicin) were injected sub-  
conjunctivally. Eye patch was applied at the end.  
There is limited local data available about  
Trabeculectomy results in primary congenital  
glaucoma. The aim of this study was to evaluate the  
outcomes of Trabeculectomy in terms of IOP control  
and its safety in terms of per-operative and post-  
operative complications in Balochistan region.  
MATERIAL AND METHODS  
This interventional case-series was conducted from  
June 2017 to December 2018 for duration of 1.5-years  
in eye department of Helpers Eye Hospital, Quetta.  
Approval from the ethical committee of Bolan Medical  
Complex Hospital (BMCH) was taken and informed  
consent was taken from parents (of all patients) before  
including them in study.  
All cases in this study had a follow up of  
minimum of 12 months. IOP measurements (and  
corneal diameter) were recorded preoperatively and  
postoperatively at 1st, 3rd and 6th month and every 6  
months thereafter under general anesthesia.  
Intraoperative and postoperative complications were  
recorded. IOP at 12th month of surgery was the final  
The patients were included in this series and  
labeled as congenital glaucoma if the following  
features were present in the patient;  
IOP > 20 mm Hg.  
Corneal diameter > 12 mm in any meridian.  
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Trabeculectomy in Congenital Glaucoma; Experience in Helpers Eye Hospital Quetta  
outcome which was considered significant if IOP was  
less than 21 mm Hg.  
These cases needed additional surgery to control IOP  
(repeat Trabeculectomy with MMC). The cause of  
failure in these cases was probably severe disease, late  
presentation and aggressive healing process in the  
pediatric population.  
Definition of surgical success was made on the  
basis of following criteria; IOP⩽21ꢀmmꢀHg, stable  
corneal diameters and clear cornea at 12th month of  
surgery. While failure was defined as either need for  
reoperation for glaucoma, persistently raised IOP over  
20 mm Hg despite topical IOP lowering medications  
or persistent hypotony (IOP < 5 mm Hg).  
In this series, small hyphema was noted in 3 cases  
(10%) which resolved completely within 3 days of  
procedure. Other than this, there were no  
intraoperative and postoperative complications (like  
shallow anterior chamber, bleb leak, hypotony,  
choroidal detachment, retinal detachment and  
endophthalmitis) till 12 months of follow-up.  
The indication of using anti-glaucoma eye drops  
was an IOP > 21 mm Hg on two consecutive follow up  
visits or continuous corneal edema postoperatively.  
Use of anti-glaucoma postoperatively was not included  
in criteria of failure.  
23.33%  
RESULTS  
In this study, a total of 30 eyes of 17 patients were  
included. Among them, there were 8 (47.05%) girls  
and 9 (52.94%) boys (Table 1).  
Table 1: Comparison of preoperative and postoperative  
mean intraocular pressure.  
76.66%  
Preoperative IOP in all cases (30 eyes)  
Postoperative IOP in successful cases  
(23 eyes – 76.66%)  
25.8 mm Hg  
15.3 mm Hg  
Complete Success  
Failure  
Fig. 1: Comparison of postoperative results at 12th month of  
Postoperative IOP in cases of failure  
(7 eyes – 23.33%)  
27.7 mm Hg  
follow-up visit.  
Cataract developed in 5 (16.66%) eyes at 6th  
month of trabeculectomy and these cases underwent  
early cataract surgery with IOL implantation to restore  
vision. Topical anti-glaucoma therapy was used in  
early postoperative days of these cases to prevent any  
inadvertent spike of IOP.  
Before surgical intervention, mean preoperative  
IOP was 25.8 mm Hg and mean horizontal corneal  
diameter was 13.76 mm. Fundus examination was  
possible in only in 17 eyes because of corneal edema.  
Twenty-three eyes (76.66%) met the success  
criteria at the time of last follow-up. The mean  
postoperative intraocular pressure for all successful  
eyes was 15.3 mm Hg. The postoperative intraocular  
pressures were considerably lower than the  
preoperative IOP levels at all follow-up visits.  
DISCUSSION  
In pediatric population primary congenital glaucoma is  
found to be the most common type of glaucoma,  
which is the leading cause of blindness in this age  
group. Anterior chamber angle anomaly is the  
underlying cause which subsequently results in raised  
intraocular pressure. It has been reported in literature  
that early treatment can prevent lifetime vision loss1,2.  
Surgery is the treatment of choice and traditionally  
trabeculectomy is ideal choice after failure of angle  
surgeries, with aim to control intraocular pressure.  
Aggressive healing response in this age group,  
challenges of poor compliance and insufficient co-  
Complete success was obtained in 15 (65.21%)  
eyes without topical anti-glaucoma medication. A  
spike of raised IOP was observed in 8 (34.78%) eyes  
at 3rd to 6th month of follow up visit, but stable values  
of IOP were achieved in these eyes with the use of  
anti-glaucoma eye drops.  
There were 7 (23.33%) eyes with trabeculectomy  
failure. In these cases, mean postoperative IOP was  
27.71 mm Hg in two consecutive follow-up visits even  
after the use of topical anti-glaucoma medications.  
Pakistan Journal of Ophthalmology, 2020, Vol. 36 (3): 253-257  
255  
Mahtab Mengal, et al  
operation with examination, are possible reasons of  
months. According to many researchers, infancy was a  
significant risk factor for surgical failure. In literature,  
the outcomes of trabeculectomy in infants under one  
year of age varied between 15–43%15,23. This  
confirmed that early diagnosis of PCG and prompt  
surgical intervention are the gateway to successful  
treatment.  
poor outcomes in this age group17,18  
.
In this study male predominance was observed  
with 52.94% boys. Literature review showed male  
dominance with percentage of 65-80%19. In another  
report, 77.7% of total sample were male20. However,  
in Japanese population female predominance was  
observed21.  
In our study, cataract developed in 5 cases  
(16.66%) during postoperative 3rd to 6th month. It was  
comparable to existing literature for same duration of  
follow up (i.e. 11.5%)24.  
In our study, IOP control after trabeculectomy was  
according to the desired level, average preoperative  
IOP in this case series was 25.8 mm Hg, while  
postoperative IOP was 15.3 mm Hg. Overall surgical  
success was achieved in 23 eyes which is 76.66% of  
total sample. This is comparable to other international  
studies. A 75% success rate of primary trabeculectomy  
was documented by Rao and his friends in their  
study16.  
Complications were minimal in our study except  
for small hyphema in 3 (10%) postoperative cases of  
trabeculectomy, which is less than internationally  
reported studies where it is documented as 19%1 and  
27.4%25. The encouraging results of our study with  
fewer complications may be due to surgeon skills,  
patient compliance with follow up and postoperative  
medications.  
Many authors state that the factors influencing  
success rate of trabeculectomy are age at time of  
surgery, early stage of disease, corneal diameter at  
presentation, surgeon expertise and technique, patient  
compliance with follow up and prompt management of  
any complication.  
Miller, another researcher, reported that use of  
anti-metabolites in primary trabeculectomy improved  
the success rate in those patients who were at higher  
risk of surgical failure, but their use is associated with  
many other serious complications9.  
There were 7 eyes (23.33%) in our series in which  
trabeculectomy failed to control IOP in spite of topical  
IOP lowering medications. 27.7 mm Hg was mean  
IOP with vascularized flat bleb in these eyes at their  
last visit. Eventually these patients underwent repeat  
trabeculectomy with MMC. Four eyes of two patients  
who presented at 1st month of their neonatal life, had  
severe disease since birth, while remaining 3 eyes of  
other 3 patients presented after 24th month of age with  
severe disease. There were large corneal diameters,  
opaque corneas and high IOP. Beck and colleagues  
reported that patients less than 1 year at the time of  
surgery were associated with very high risk of  
failure22.  
Limitation of our study was small sample size.  
The results of the study cannot be generalized because  
the study was conducted in a single center.  
CONCLUSION  
Primary trabeculectomy is an effective operation for  
primary congenital glaucoma when performed early  
and followed properly and regularly for any  
decompensation.  
Ethical Approval  
The study was approved by the Institutional review  
board/Ethical review board.  
Corneal health (diameters and clarity) is also a  
factor of high surgical success rate. Al-Hazmi et al,  
had reported that a better surgical outcome of  
trabeculectomy could be achieved when preoperative  
corneal diameter was < 13 mm and patient was < 1  
year of age9.  
Conflict of Interest  
Authors declared no conflict of interest.  
We observed in our study that the patients who  
presented within 3 months to 18 months and who  
underwent early surgery showed better results than  
patients who presented with age under 1 month. These  
patients had untreated advanced disease with corneal  
diameters larger than 13.5 mm and age more than 24  
Authors’ Designation and Contribution  
Mahtab Mengal; Senior Registrar: Concept,  
Manuscript writing, Data collection and analysis.  
M. Afzal Khan; Assistant Professor: Data collection  
and final review.  
256  
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Trabeculectomy in Congenital Glaucoma; Experience in Helpers Eye Hospital Quetta  
12. Mullaney PB, Selleck C, Al-Awad A, Al-Mesfer S,  
Zwaan J. Combined trabeculotomy and trabeculectomy  
as an initial procedure in uncomplicated congenital  
glaucoma. Arch Ophthalmol. 1999; 117 (4): 457–60.  
13. Mandal AK, Bhatia PG, Bhaskar A, Nutheti R.  
Long-term surgical and visual outcomes in Indian  
children with developmental glaucoma operated on  
within 6 months of birth. Ophthalmology. 2004; 111  
(2): 283–90.  
Aimal Khan; Assistant Professor: Data collection and  
final review.  
Manzoor Ahmed; Senior Registrar: Data collection,  
literature search.  
Rabia Khawar Chaudhry; Paediatric Ophthalmologist:  
Manuscript writing, literature search.  
Nasar Qamar Khan; Consultant Ophthalmologist:  
14. Fulcher T, Chan J, Lanigan B, Bowell R, O’Keefe  
M. Long-term follow up of primary trabeculectomy for  
infantile glaucoma. Br J Ophthalmol. 1996; 80 (6):  
499–502.  
15. Al-Hazmi A, Zwaan J, Awad A, Al-Mesfer S,  
Mullaney PB, Wheeler DT. Effectiveness and  
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glaucoma surgery. Ophthalmology, 1998; 105 (10):  
1915–20.  
Statistical analysis, final review  
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