Recently, the article “Delayed-Onset Symptomatic hyphema after ab interno trabeculotomy surgery” reported that 4.6% of 262 cases demonstrated postoperative spontaneous delayed-onset hyphema after Trabectome surgery. Median time to onset of the hyphema was 8.6 months (range, 2 to 31 months) after surgery. The authors suggest the mechanism of these postoperative bleeds related to exertion or sleep position in the presence of an open blood-aqueous barrier. We would like to report a patient with spontaneous blood reflux during cataract surgery who had undergone trabecular meshwork ablation 2 years earlier. Exploring the cause of this delayed-onset intraoperative bleed may offer an alternative explanation for the postoperative hyphemas described.

A 79-year-old woman with open-angle glaucoma sought treatment for visual field worsening and optic nerve head progression. Despite maximum medical therapy and laser trabeculoplasty, intraocular pressure was uncontrolled. The patient underwent trabecular meshwork ablation over 120 degrees. The postoperative course was uneventful. Two years after the procedure, the patient demonstrated a visually significant cataract. Phacoemulsification was uneventful. However, at the time of viscoelastic removal, spontaneous bleeding was noted across 90 degrees of the nasal angle. The blood was irrigated and viscoelastic was used to tamponade the hemorrhage. During surgery, there had been no loss of anterior chamber stability or manipulation of iris to explain the bleeding. The patient was not administered anticoagulants. Postoperative gonioscopy revealed blood in the area of previous ablation. Anterior segment optical coherence tomography revealed an open cleft.

A combination of factors may be responsible for the intraoperative blood reflux. Perhaps this is a presentation similar to that found with Swan syndrome. This syndrome describes focal vascularization from an ingrowth of episcleral vessels at a previous wound site and results in spontaneous intraocular bleeds months to years later. Another possibility is that angle ablation leads to long-term sensitization of the tissue, making it more susceptible to damage. It is also possible that a membrane developed in the area of prior ablation, and bleeding occurred when the cleft was reopened abruptly.

The aforementioned causes are alternative explanations for the spontaneous delayed-onset postoperative hyphemas. These clinical findings indicate that there are still unanswered questions related to the pathophysiologic features of trabecular meshwork ablation. It is unknown if increased aqueous outflow through the cleft causes long-term changes to the trabecular meshwork, collector channels, or episcleral venous pressure. Moreover, it emphasizes the need for studies that objectively evaluate intraocular pressure fluctuations and angle structure during and after anterior segment surgery.