Optic Nerve Head Cupping Reversal Tied to Axial Length, Cup Depth Reductions

Clinical optic nerve head (ONH) cupping reversal following intraocular pressure (IOP) lowering surgery is associated with axial length reduction and a decrease in cup depth, according to research published in the American Journal of Ophthalmology. However, pre-intervention ONH damage likely persists.

ONH cupping reversal occurs in nearly half of eyes surgically treated for pediatric glaucoma, and it remains unclear how this phenomenon affects ONH health and axonal loss. Researchers conducted a retrospective, observational case series to evaluate ONH and macular structural changes and cupping reversal among very young patients (mean age, 1.14±0.93 years; 57% boys). Spectral domain-optical coherence tomography (SD-OCT) was performed pre and postoperatively. Participants underwent measurements of the peripapillary retinal nerve fiber layer (pRNFL), transverse horizontal diameter of Bruch membrane opening (BMO-D) and cup depth.

After excluding patients with poor quality images and ongoing optic nerve swelling following an IOP decrease, researchers evaluated 18 eyes of 14 patients and performed follow-up a mean 127±149 days following surgery.

The report shows post surgical mean reductions in IOP (45%), cup-to-disc ratio (0.30±0.12; P <.001), axial length (0.43±0.28 mm; P <.001), and cup depth (46%; P <.001).

No significant changes in global or sectoral pRNFL, 3mm macular total and segmented retinal layer volumes, and BMO-D were noted postoperatively.

Preoperative ONH cup-to-disc ratio was weakly inversely correlated with preoperative (P =.022; R=0.286) and postoperative (P =.021; R=0.290) average RNFL thickness. 

“In children who have undergone treatment for glaucoma, ONH cupping reversal does suggest IOP-reduction-related stabilization,” according to the researchers. “However, for young children whose functional measures of vision are limited and for whom the clinical appearance of the ONH may be misleading, OCT measures of the pRNFL (and macular parameters) may be a valuable indicator of ONH health and a reliable parameter with which to quantify baseline glaucomatous optic nerve damage, and to monitor for disease progression.”

Study limitations include a small sample size and short duration of follow up.