This article is more than 5 years old. Information may no longer be current.
Cupping reversal after IOP-lowering surgery may correlate to reduction in scleral canal area
Ophthalmology. 2011;118(10):2008-2013.
Click Here to Manage Email Alerts
The scleral canal may shrink in area when cupping reversal occurs after IOP-lowering congenital glaucoma surgery, a study suggested.
"The optic disc cup decreases in size and depth, and the scleral ring shrinks. However, the magnitude of the observed decrease in disc area (~6%) is probably insufficient to explain all components of the observed changes in disc appearance. Cupping reversal is most likely to occur because of both shrinking of the scleral canal and a forward movement of the lamina cribrosa and overlying neural tissue," the authors wrote.
Of 29 eyes undergoing incisional surgery, 15 eyes of nine children showed cupping reversal, and 14 eyes of 12 children did not. The retrospective, single-center, observational case series showed that disc area decreased by 6.8% in the reversal group and increased by 4.3% in the no reversal group (P < .0001).
Percentage changes in disc area were correlated to percentage changes in IOP (P = .0025), as well as axial length (P = .0028). According to the authors, cupping reversal is less frequent in adults, possibly owing to a lower elasticity of the scleral ring.
Study limitations included the manual outlining of optic disc margins and the use of a polygon to connect vascular landmarks as a reference to control for magnification changes. This assumes that the polygon's geometry remains static and could therefore translate to an underestimation of scleral canal shrinkage.