Ab interno goniotomy plus ab externo trabeculotomy can improve the success rate of buphthalmos surgery in primary congenital glaucoma and reduce intraocular pressure (IOP), according to research published in Clinical Ophthalmology. 

In a prospective, randomized study, researchers sought to qualify the outcome of goniotomy plus trabeculotomy to surgically treat eyes with primary congenital glaucoma and a corneal diameter larger than 14 mm. Fifty eyes from 50 patients (52% boys; mean age, 18.86 years ± 9.94 months) were included in the study cohort. 

Preoperatively, patients underwent a complete examination of the anterior segment, intraocular pressure (IOP) measurement, gonioscopic examination of the anterior chamber, and corneal clarity measurements. During the surgery, goniotomy was performed first, followed by trabeculotomy. All patients were reexamined 1 day, 1 week, 1 month, and 3 months, then every 3 months, for a total 24-month follow-up period. 

The primary study outcome was a reduction in IOP; secondary outcomes included complications, factors that affected the success rate, and the need for further surgical intervention. 


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Within the cohort, 38% of patients showed positive consanguinity. Mean horizontal corneal diameter was 14.56 mm (± 0.8 mm, range, 14 mm to16 mm). Axial length range was between 20 mm and 22 mm (mean, 20.98 mm ± 0.8 mm) and mean CD ratio was 0.8 (± 0.4) with a range from 0 to 1. Preoperative IOP was between 21 mm Hg and 36 mm Hg (mean, 29.56 mm Hg ± 3.4 mm Hg). 

Postoperative assessments of IOP demonstrated a significant drop to 12.64 mm Hg (± 2.5 mm Hg) at 1 month; at 3, 6, 9, and 12 months, slight increases were noted (14.12 mm Hg ± 3.2 mm Hg, 16.8 mm Hg ± 5.5 mmHg, 14.44 mm Hg ± 2.3 mm Hg, and 14.3 mm Hg ± 1.6  mm Hg, respectively). IOP then plateaued for 9 months, and increased nonsignificantly to 14.32 mm Hg (± 1.7 mmHg) at 18 months and 18.3 mm Hg (±1.7 mm Hg) at 24 months. 

When comparing postoperative readings, there were statically significant changes and 1, 3, 6, and 9 months compared with the prior readings. 

Investigators noted a statistically significant positive correlation between preoperative IOP, horizontal corneal diameter, axial length, and CD ratio; significant negative correlations were noted between preoperative IOP and age at onset. 

Additional positive correlations were detected between postoperative IOP and horizontal corneal diameter, axial length, and CD ratio; these results had “high significance.” 

Successful outcomes were recorded in 47 patients; 35 patients experienced complete success. Hyphema was reported in 46% of patients, while 54% experienced no postoperative complications. 

Three patients with failed surgery required further successful surgical intervention. Statistically significant relations between surgical outcome and variables for consanguinity, age, axial length, horizontal corneal diameter, preoperative IOP, and CD ratio. 

Study limitations include the small number of cases and the absence of a control group. 

“Combined ab interno goniotomy with ab externo trabeculotomy may be a highly recommended surgical choice for primary congenital glaucoma causes with a corneal diameter larger than 14 mm,” the study says. 


Reference

Helmy H. Ab interno goniotomy combined with ab externo trabeculotomy in advanced primary congenital glaucoma patients: 2-year follow-up. Clin Ophthalmol. 2021;15:565-574. doi:10.2147/OPTH.S292168.