Outcome of Gonioscopy-Assisted Transluminal Trabeculotomy in Glaucoma Following Pediatric Cataract Surgery. A Prospective Interventional Case Series.
Phase: NA
Conditions: Glaucoma Following Pediatric Cataract Surgery
Sponsor: Cairo University

 
 
 
 
Title : Gonioscopy-Assisted Transluminal Trabeculotomy in Pediatric Glaucoma 
Following Cataract Surgery
 
 
 
protocol record (MD-196-2024)
 
 
 
 
Date: 25 October 2025
 

 

 
 
 
 

Research Template 
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Final Version: April 2019 
 
 
Faculty of Medicine, Cairo University Postgraduate 
Research Protocol Template 
 
1. Study 
a- Proposed 
Study 
Title: 
Outcome 
of 
Gonioscopy-Assisted 
Transluminal 
Trabeculotomy in glaucoma following pediatric cataract surgery. A Prospective 
interventional Case Series. 
b- Degree:  MD 
c- Date of Registration of MD: March 2024 
2. Candidate 
a.  Name: Marwa Elsayed Soliman Ahmed 
b.  Occupation: Ophthalmology specialist 
c. Affiliation: Kasr-Alainy. 
d.  Email addresses: marwaalsayedsoliman@gmail.com 
e.  Full mailing address: 10th Elyarmok Street, Nasr City 
f. 
Phone number: 01067562844 
3. Supervisors Contact Information 
a. Principal supervisor: 
Name: Prof Dr Hala Mostafa Mohamed Elhilali 
Department: Ophthalmology 
Phone number: +20 122 313 7489 
E-mail addresses: halaelhilali@yahoo.com 
b. Other supervisors: 
1- Prof: Dr. Ghada Ismail Gawdat 
Department: Ophthalmology department 
Phone: +20 100 258 1682 
E-mail: ghadagawdt@yahoo.co.in 
2- Prof Dr Yasmine Mohamed Elsayed 
Department: Ophthalmology 
Phone: 01222202424 
Email: Yasminemelsayed@yahoo.com 

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3- Lecturer .Dr .Fayrouz Mohamed Aboalazayem 
Department: Ophthalmology department 
Phone: +20 100 741 9500 
4. Scientific committee approval 
(Was it scientifically approved by the department?) 
Date of approval: 
5. Background and Rationale: (Describe the research question and justification for 
undertaking the study explaining the aspects of novelty in the study) 
Glaucoma following pediatric cataract surgery is a recognized postoperative complication
that may require surgical management when medical therapy is insufficient. Gonioscopy-
assisted transluminal trabeculotomy (GATT) is a minimally invasive conjunctiva-sparing
procedure designed to improve aqueous outflow through circumferential trabeculotomy. 
This prospective interventional case series will evaluate outcomes of GATT in eligible 
pediatric patients with glaucoma following cataract surgery treated at Cairo University 
Hospitals. Participants will undergo preoperative ophthalmic assessment, standardized
surgical intervention, and scheduled postoperative follow-up visits. Outcomes to be assessed
include intraocular pressure, use of glaucoma medications, and safety parameters during 
follow-up. 
 
 

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6. Objectives: (describe specific objectives or hypotheses behind the study) 
 To evaluate the safety and effectiveness of gonioscopy-assisted transluminal 
trabeculotomy (GATT) in children with glaucoma following cataract surgery, 
with assessment of intraocular pressure control, postoperative medication 
requirements, and procedure-related complications.. 
7. Study Design: (Please fill in the appropriate study design, see attached PDF guide) 
- 
Descriptive: - Survey (cross sectional) 
- Qualitative 
- 
Analytic: - Observational: - Case-control study 
- Cross sectional analytic study 
- Cohort (Longitudinal) study 
- Experimental: - Randomized Clinical Trial 
Phase: 
- Non-randomized clinical trial 
- Animal study 
- Cellular study 
- 
Others: Please describe: 
Prospective interventional Case Series. 

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Final Version: April 2019 
 
 
8. Study Methods 
 
Population of study: 
 
 
Patients presenting to the ophthalmology outpatient clinic of – 
Abuelresh - Cairo University Hospital with pediatric glaucoma following 
cataract surgery aging from 1-12 years. 
 
Study location: 
 
 
The study will be conducted at Cairo University Hospitals. 
 
- 
Inclusion criteria: 
- 
Patients with pediatric glaucoma following cataract surgery and clear corneas 
allowing visualization of the angle. 
Based on the Childhood Glaucoma Research Network(CGRN), GFCS is 
secondary glaucoma that meets glaucoma definition after cataract 
surgery is performed (Glaucoma: 2 or more of the following are 
required: (1) IOP >21 mm Hg (2) Visual fields: reproducible visual field 
defect that is consistent with glaucomatous optic neuropathy with no 
other observable reason for the visual field defect. (3) Axial length: 
progressive myopia or myopic shift with increased ocular dimensions 
that outpace normal growth. (4) Optic nerve: progressive increase in 
cup-to-disc ratio, cup-to-disc asymmetry ≥0.2 when optic discs are of 
similar size, and focal rim thinning. 
- 
Patients with pediatric glaucoma following cataract surgery and clear corneas 
allowing visualization of the angle who underwent previous glaucoma surgery. 
- 
Exclusion criteria: - 
- 
Eyes with retinal pathology. 
- 
Eyes with synechial angle closure involving > 180 degrees of the iridocorneal 
angle. 
- 
Methodology in details: 
- 
All selected patients’ carers will receive a thorough explanation of the 
study design and aims and will sign an informed consent. 
 
Pre-operative evaluation of all participants will include: 

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- 
Best corrected visual acuity (BCVA) using Snellen’s chart whenever 
possible according to age. 
- 
Central corneal thickness (CCT). 
- 
Horizontal corneal diameter (HCD). 
- 
Slit lamp examination of the anterior segment. 
- 
Gonioscopy using Swan Jacob lens. 
- 
Intraocular pressure measurement using Perkins applanation 
tonometry. 
- 
Dilated fundus examination by binocular indirect ophthalmoscopy 
and slit-lamp bio-microscopy using +90 D Volk condensing lens. 
 
Surgical technique: 
GATT surgery: 
- 
All surgeries will be performed under general anesthesia, The operating 
microscope is tilted 45 degrees,, the head of the bed is elevated, and the head 
of the patient is tilted to the opposite side. While sitting on the temporal side 
of the patient a temporal corneal incision is created by a 23 Gauge MVR. An 
inferior or superior paracentesis is created. The anterior chamber (AC) is filled 
using cohesive viscoelastic then the angle is visualized by direct gonioscopy 
using Swan Jacob lens. Nasal goniotomy for 2 clock is performed by using 
MVR blade to incise the inner wall of Schlemm’s canal. Cohesive OVD is used 
to open the lips of the incision, then 5/0 prolene after being blunted by cautery 
pen is threaded inside Schlemm’s canal guided it inside the canal using 23-
gauge vitreoretinal forceps until we retrieve it from the opposite end of the 
incision. The two ends of the 5/0 prolene suture are pulled to incise the 
Schlemm’s canal and trabecular meshwork over 360°.The AC is washed by 
BSS followed by injection of air to tamponade any bleeding then the wound is 
hydrated or sutured. 
 
Post operative assessment: 
At day 1, 1 week, 1month ,3months and 6 months. 
- 
Each follow up visit will include slit lamp evaluation of the anterior segment, 
as well as IOP measurement using Perkins applanation tonometry with 
documentation of the antiglaucoma medications used. BCVA and cup-to-disc 

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-
- 
- 
 
ratio will be assessed at 1 month post-operative and will be compared at the 
final follow-up to the preoperative measurements. 
- Surgical success will be defined as: complete if IOP is less than or equal to 21 
mmHg without medications and qualified success if IOP is less than or equal 
to 21 mmHg with medications. Failure will be the inability to achieve such a 
pressure, the need for another glaucoma operation or the development of a 
sight-threatening complication (e.g. retinal detachment and endophthalmitis). 
 
Intervention: 
 
Diagnostic intervention 
 
Therapeutic intervention (Gonioscopy-Assisted Transluminal Trabeculotomy in 
patients with pediatric glaucoma following cataract surgery). 
 
No intervention 
 
 
Does the research involve? 
 
Human participants 
Biological samples/Tissues 
Identifiable private data/Information 
 
 
Type of consent of study participants: 
 
 
Written consent 
Oral consent 
No consent needed (Please justify) 
 
Potential risks: 

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 
Risks of surgery: hyphema, transient hypotony, corneal edema, anterior chamber 
inflammation, endophthalmitis, recurrence of IOP elevation, accidental IOL 
damage or iris injury 
Confidentiality of data: All participants will be coded, and data entry will be 
using 
these 
codes. 
All data of the patients will be saved in secure files. 
 
9- Study outcomes: 
- 
Primary Outcome Measure 
- 
Change in intraocular pressure from baseline to 6 months postoperatively.  
- 
Number of antiglaucoma medications required at 6 months.  
- 
Secondary Outcome Measures 
- 
Intraoperative and postoperative complications through 6 months.  
- 
Need for additional glaucoma surgery through 6 months.  
- 
Surgical success according to predefined study criteria at 6 months. 
 
 
10- Sample size (number of study subjects included and justification including the clinical and 
statistical assumptions supporting sample size calculation) 
 
Sample size was estimated based on anticipated change in intraocular pressure 
from baseline after intervention, with statistical power of 90%, significance level 
of 0.05, and allowance for potential dropout. The planned enrollment is 20 
participants. 
 
11- Statistical analysis (Please describe your data analysis plan) 
Statistical analysis will be conducted using SPSS 27th edition, categorical variables 
will be presented in count and percent and compared between groups using Fisher 
exact test. Quantitative variables will be presented in mean, standard deviation, 
minimum and maximum, it will be compared between groups using Student T test after 
 

Research Template 
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Final Version: April 2019 
 
 
 
normality testing using Shapiro Wilk test. Correlation between two quantitative 
variables will be conducted using Pearson correlation test. Any p value <0.05 will be 
considered significant. 
 
12- Source of funding: (Please include source of funding even if self-funding) 
- 
Faculty of Medicine, Cairo University 
- 
Other sources: 
Please specify: 
 
13- Time plan: 
- When to start? Once the thesis is accepted by ethical committee 
- When expected to finish? 20 months 
- When to publish? 
 
14- References: 
1- Beck AC, Chang TC, Freedman SWeinreb RN, Grajewski A, Papadopoulos M, Grigg 
J, Freedman S. Section 1: Definition, classification, differential diagnosis. World 
Glaucoma Association Consensus Series—9: Childhood Glaucoma. 
2- Beck AD, Freedman SF, Lynn MJ, Bothun E, Neely DE, Lambert SR, Infant 
Aphakia Treatment Study Group. Glaucoma-related adverse events in the Infant 
Aphakia Treatment Study: 1-year results. Archives of ophthalmology. 2012 Mar 
12;130(3):300-5. 
3- Freedman SF, Lynn MJ, Beck AD, et al. Glaucoma-related adverse events in 
the first 5 years after unilateral cataract removal in the Infant Aphakia Treatment 
Study. JAMA Ophthalmol. 2015;133:907–914. 
4- Freedman SF, Beck AD, Nizam A, et al. Glaucoma-related adverse events at 10 
years in the Infant Aphakia Treatment Study: a secondary analysis of a 
randomized clinical trial. JAMA Ophthalmol. 2021;139: 165–173. 

Research Template 
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Final Version: April 2019 
 
 
5- Chen TC, Walton DS, Bhatia LS. Aphakic glaucoma after congenital cataract 
surgery. Archives of ophthalmology. 2004 Dec 1;122(12):1819-25. 
6- Mandal AK, Netland PA. Glaucoma in aphakia and pseudophakia after 
congenital cataract surgery. Indian journal of ophthalmology. 2004 Jul 
1;52(3):185-98. 
7- Zhang Y, Song Y, Zhou Y, Bai B, Zhang X, Chen W. A comprehensive review 
of pediatric glaucoma following cataract surgery and progress in treatment. The 
Asia-Pacific Journal of Ophthalmology. 2023 Jan 1;12(1):94-102. 
8- Saheb H, Ahmed II. Micro-invasive glaucoma surgery: current perspectives and 
future directions. Current opinion in ophthalmology. 2012 Mar 1;23(2):96-104. 
9- Gillmann K, Mansouri K. Minimally invasive glaucoma surgery: where is the 
evidence? Asia Pac J Ophthalmol (Phila). 2020;9:203–214. 
10- Areaux RG Jr, Grajewski AL, Balasubramaniam S, et al. Trabeculotomy ab 
interno with the Trab360 device for childhood glaucomas. Am J Ophthalmol. 
2020;209:178–186. 
11- Khouri AS, Wong SH. Ab interno trabeculectomy with a dual blade: surgical 
technique for childhood glaucoma. Journal of Glaucoma. 2017 Aug 
1;26(8):749-51. 
12- Grover DS, Godfrey DG, Smith O, Feuer WJ, de Oca IM, Fellman RL. 
Gonioscopy-assisted transluminal trabeculotomy, ab interno trabeculotomy: 
technique report and preliminary results. Ophthalmology. 2014 Apr 
1;121(4):855-61. 
13- Quan AV, Chen J, Wang YE, Vanner EA, Grajewski AL, Hodapp EA, Chang 
TC. Factors associated with gonioscopy-assisted transluminal trabeculotomy 
(GATT) complications and failure in children. American journal of 
ophthalmology. 2022 Sep 1;241:168-78. 

Ophthalmology sheet 
 
 
Outcome of Gonioscopy-Assisted Transluminal Trabeculotomy in 
glaucoma following pediatric cataract surgery. A Prospective Case 
Series. 
 Code: 
 
1. Sociodemographic data: 
1.1 Gender: 
1.2 Age: 
 
2. History: 
2.1 Age of cataract extraction. 
2.2 Any systemic co-morbidities. 
2.3 Any other ocular surgery. 
2.4 Any ocular Trauma. 
 
 
3.Pre-operative Examination: 
 
2. OD 
OS 
3.1 UCVA 
3.2 BCVA 
3.3 Refraction 
3.4 Intraocular 
pressure 
3.5 Anterior segment 
examination 
3.6 Fundus 
examination 
3.7 Gonioscopy 
3.8 Automated perimetry 
 
 

4. Post-operative Examination Day 1, week 1, 1 month, 3 months, 6 
months. 
 
3. OD 
OS 
4.1 UCDVA 
4.2 BCDVA 
4.3 refraction 
4.4 Intraocular pressure 
4.5 Anterior segment 
4.6 Anti glaucoma medications 
used 
4.7 Gonioscopy(starting from 1st 
month) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Version …. , Date …… 
 
 
Informed Consent Form
 
Study Title
 
GATT in Pediatric Glaucoma Following Cataract Surgery
 
 
Introduction
 
Your child is invited to participate in a research study 
evaluating a surgical procedure used to treat glaucoma after 
cataract surgery.
 
 
Purpose
 
To assess the safety and effectiveness of GATT in controlling 
eye pressure.
 
 
Procedures
 
Your child will undergo surgery and regular follow-up visits 
including eye examinations and pressure measurements.
 
 
Risks
 

 
Bleeding (hyphema)
 

 
Infection (rare)
 

 
Need for additional surgery
 
 
Benefits
 

 
Potential reduction in eye pressure
 

 
Decreased need for medications
 
 
Confidentiality
 
All data will remain confidential and anonymized.
 
 
Voluntary Participation
 
Participation is voluntary. You may withdraw at any time.
 
 
Consent Statement
 
I have read and understood the information above and agree to 
participate.
 
Guardian Name: __________
 
Signature: __________
 
Date: __________