Trabeculotomy opening size and IOP reduction after Trabectome® surgery

BackgroundTrabeculotomy with the Trabectome® is an effective surgical procedure to lower intraocular pressure (IOP). However, in some patients it does not lead to a significant IOP reduction despite a gonioscopically well visible opening of Schlemm’s canal. This study investigated whether the size of the trabeculotomy opening and other parameters, including anterior chamber depth (ACD) are related to IOP reduction.MethodsRetrospective observational case series with 93 eyes of 93 patients who underwent Trabectome surgery. Trabeculotomy opening and ACD were measured with an anterior segment swept source OCT. IOP was taken pre-operatively and at a single follow-up visit [follow-up time 125 ± 66 days (mean ± SD)]. The relationship between IOP reduction and OCT parameters and possible confounding factors was analyzed in a multiple linear regression model.ResultsThe trabeculotomy opening size did not correlate with IOP reduction (slope of regression line = 0.0016; 95% confidence interval of slope: −0.025 to 0.028). The same applied for all other parameters tested, including ACD, which showed a tendency towards better IOP reduction with a deeper AC (slope = −1.9; 95% confidence interval: −5.54 to 1.73). Comparison between the 1st and 4th quartile of the trabeculotomy opening showed a significantly higher ACD in the largest trabeculotomy opening quartile (3.32 ± 0.05 mm vs. 3.16 ± 0.04 mm; p = 0.031).ConclusionsThe fact that the trabeculotomy opening size did not correlate with IOP reduction points to the poorly understood role of the intrascleral aqueous outflow pathway in glaucomatous IOP elevation. A deeper AC might be a factor promoting a larger trabeculotomy opening.

[1]  W. Feuer,et al.  Episcleral Venous Fluid Wave Correlates with Trabectome Outcomes: Intraoperative Evaluation of the Trabecular Outflow Pathway. , 2015, Ophthalmology.

[2]  D. Minckler,et al.  Trabectome (trabeculectomy-internal approach): additional experience and extended follow-up. , 2008, Transactions of the American Ophthalmological Society.

[3]  Ernst R Tamm,et al.  The trabecular meshwork outflow pathways: structural and functional aspects. , 2009, Experimental eye research.

[4]  Kevin Taliaferro.  Ab interno trabeculectomy: development of a novel device (Trabectome) and surgery for open-angle glaucoma. , 2007, Journal of glaucoma.

[5]  R Core Team,et al.  R: A language and environment for statistical computing. , 2014 .

[6]  B. Francis,et al.  Clinical results with the Trabectome for treatment of open-angle glaucoma. , 2005, Ophthalmology.

[7]  Hadley Wickham,et al.  The Split-Apply-Combine Strategy for Data Analysis , 2011 .

[8]  T. Filippopoulos,et al.  Novel surgical procedures in glaucoma: advances in penetrating glaucoma surgery , 2008, Current opinion in ophthalmology.

[9]  D. Boehringer,et al.  Trabectome surgery for primary and secondary open angle glaucomas , 2013, Graefe's Archive for Clinical and Experimental Ophthalmology.

[10]  M. Braga,et al.  Exploratory Data Analysis , 2018, Encyclopedia of Social Network Analysis and Mining. 2nd Ed..

[11]  E. Lütjen-Drecoll,et al.  Structural changes of the trabecular meshwork in different kinds of glaucoma. , 2009, Experimental eye research.

[12]  E. V. D. Merwe,et al.  Advances in imaging the blood and aqueous vessels of the ocular limbus. , 2010, Experimental eye research.

[13]  P. Harasymowycz,et al.  Goniopuncture in the Treatment of Short-term Post-Trabectome Intraocular Pressure Elevation: A Retrospective Case Series Study , 2013, Journal of glaucoma.

[14]  J. Rohen,et al.  Studies on the histology of the inner wall of Schlemm's canal. , 1959, American journal of ophthalmology.

[15]  E. Ritman,et al.  Imaging the aqueous humor outflow pathway in human eyes by three-dimensional micro-computed tomography (3D micro-CT). , 2011, Experimental eye research.