After glaucoma surgery, early eye-pressure changes, not the procedure, shape vision outcomes

For patients with severe glaucoma, the type of operation may matter less than what happens to eye pressure during the first month afterward. A large clinical study found that early pressure changes, shaped by the patient’s preoperative vision, were the strongest factor linked to loss of central vision.

Glaucoma progressively damages the optic nerve. In advanced disease, preserving the remaining central vision becomes the main treatment goal. Patients may undergo trabeculectomy or Ahmed valve implantation to lower eye pressure, but some experience a sharp and serious loss of central vision after surgery. Previous debate focused largely on which surgical technique offered greater safety.

Researchers from Yonsei University College of Medicine analyzed long-term follow-up data from 523 eyes treated for severe glaucoma at Severance Hospital and Gangnam Severance Hospital between January 2005 and October 2023. Central-vision loss occurred in 83 eyes, or 15.9%. The study found no statistically meaningful difference between the two operations in either the rate of vision loss or final surgical outcomes.

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This study is meaningful because large-scale data demonstrated that tailored eye-pressure management strategies based on patients’ visual condition before and after surgery are essential, rather than applying uniform pressure-management criteria after severe glaucoma surgery.

The risk pattern changed according to the patient’s vision before surgery. Patients whose central vision remained relatively well preserved, with visual acuity above 0.1, were more vulnerable to early low eye pressure below 8 mmHg. Patients whose central vision had already declined to 0.1 or lower were more vulnerable to early high pressure above 21 mmHg. The researchers said mechanical changes affecting the macula and optic nerve could help explain the first pattern, while reduced blood flow and ischemic damage could explain the second.

Patients with persistent high eye pressure soon after surgery showed the poorest vision recovery over time. Associate Professor Woong-Rak Choi said the findings support pressure-management strategies tailored to each patient’s visual condition rather than one uniform standard. The study appeared in the International Journal of Surgery.

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The findings are expected to provide important evidence for establishing new clinical management guidelines for patients with severe glaucoma after surgery.