Subscleral Trabeculectomy With Iris Incarceration in Buphthalmous

Subjects and Methods This was a prospective study of eyes of 40 eyes with Buphthalmous in 25 infants (15 bilateral and 10 with unilateral) divided into 2 groups. Group 1 (20 eyes) those underwent Subscleral trabeculectomy (SST) with iris incarceration a new modification to SST and group 2 conventional rigid trabeculotomy through a period of 4 years between Jan., 2015 and Feb., 2019. The local board committee approved the study as well as all patients' relatives signed consent and the study was in agreement with Declaration of Helsinki Tents. The primary outcomes were the mean intraocular pressure (IOP) measured under General Anesthesia (GA) and the number of repeated surgical intervention. Complete success was defined as an IOP ≤18 mm Hg without the use of anti-glaucoma drugs, a qualified success when medications were used to reach this target and failure if the target IOP would not be reached in spite of full anti-glaucoma medication and the infant needs another anti-glaucoma procedure and the number of repeated surgical intervention were recorded. The secondary outcomes were studding bleb formation, the change in corneal diameter (CD), cup disc ratio (C/D), and axial length (AXL).

Preoperative examinations: History taking including, age, sex, laterality, family history and consanguinity, anti-glaucoma drugs. Ophthalmological examinations were done under GA, includes slit lamp examination, corneal clarity, horizontal corneal diameter, fundus examination and measurement of cup disc ratio, IOP with Perkins tonometer, and axial length by ultrasonography. The demographic data were registered as in (Table 1).

Surgical procedure:

All procedures were done by one of the Authors under GA. In group 1 SST with iris incarceration Steps in brief:-

• Clear corneal traction suture by vicryl 7/0 in the superior peripheral part 1 mm from the limbus
• Conjunctival peritomy with fornix based conjunctival flap was done in the upper temporal quadrant.
• Half thickness rectangular scleral flab 3.5 x 4.5 mm was constructed.
• Paracentesis to lower IOP and allows reformation of anterior chamber when needed and check filtration.
• Block trabeculectomy were done manually by knife and vannas scissors.
• Iris incarceration was done by cutting the iris into 2 pillars, one pillar incarcerated under the scleral flap and the other one reposted with iris repositor resulting in inverted coma shaped pupil.
• Scleral flap was closed with interrupted 10/0 nylon suture and Conjunctival flap with contentious 10/0 nylon suture then injection of subconjunctival steroid, antibiotic and eye dressing.

In group 2 trabeculotomy Steps in brief:-

• Conjunctival peritomy with fornix based Conjunctival flap was done in the upper temporal quadrant.
• Superficial rectangular scleral flab 3.5 x 4.5 mm and then small triangular deep scleral flab (modified technique) with deroofing of Schlemm's canal anteriorly to the scleral spur were done.
• Radial incision into the scleral bed and cutting Schlemm's canal, exposure of its opening and dilatation of the ostia by injection of Healon or trabeculotome.
• Paracentesis to lower IOP allows reformation of anterior chamber when needed and check filtration.
• Hans's trabeculotome was inserted into Schlemm's canal from one side and centripetal rupture of the canal through trabecular meshwork into the anterior chamber about 70- 90 degree and repeated on the other side.
• Scleral flap was closed with interrupted 10/0 nylon suture and Conjunctival flap with contentious 10/0 nylon suture then injection of subconjunctival steroid, antibiotic and eye dressing

Post-operative management:

The patients were prescribed topical tobradex (tobramycin- dexamethasone) eye drops QID and tapering through 4-6 weeks and Vigamox (moxifloxacin 0.3 mg, Alcon Co) eye drops QID for 2 weeks. Scheduled follow up visits were advised next postoperative day, one week, monthly for three months then each three months for 2 years. Each visit the child subjected to full ophthalmological examinations previously mentioned and antiglaucoma medications were prescribed when needed (IOP>18 mmHg) or glaucoma progression starting by one drug beta blockers and adding dorzolamide or prostaglandin to reach the target IOP. Another glaucoma procedure were done if the IOP > 18 mmHg with maximum tolerated medication. Patient's data of the 2 years follow-up were recorded. The results of one week, 1 month, 3 months, 6 months, 1 year and 2 years were included in the statistical analysis.

Statistical analysis:

Data were collected, for statistical analysis done by using SPSS statistical package version 20. Descriptive statistics for the (mean ±SD) were done. Paired student's t-test was used for comparison of two related parameters preoperative and postoperative. For all tests (P value) was considered significant if < 0.05.