Does Chronic Hypotony following Trabeculectomy Represent Treatment Failure?

Area of Science:

• Ophthalmology
• Glaucoma Surgery
• Ocular Physiology

Background:

• Trabeculectomy is a common glaucoma surgery.
• Postoperative hypotony, defined as low intraocular pressure (IOP), can occur after surgery.
• The long-term complications and precise definition of chronic hypotony require further clarification.

Purpose of the Study:

• To determine the complication rate in eyes with chronic hypotony post-trabeculectomy.
• To establish a clear definition for postoperative hypotony.

Main Methods:

• A retrospective case-control study compared 34 eyes with chronic hypotony to 34 control eyes.
• Chronic hypotony was defined as IOP < 6 mm Hg on two visits at least 3 months post-trabeculectomy.
• Outcomes included visual acuity, choroidal effusion, hypotensive maculopathy, and cataract progression.

Main Results:

• Hypotensive maculopathy occurred in 23.5% of hypotony eyes versus 0% in controls (p < 0.01).
• No significant differences in choroidal effusion or cataract rates were found.
• Eyes with hypotony had a higher complication rate (67.6%) compared to controls (41.2%).
• Spontaneous hypotony recovery was observed in 32.4% of affected eyes.

Conclusions:

• Chronic hypotony following trabeculectomy is associated with a higher incidence of sight-threatening complications, particularly maculopathy.
• Not all cases of chronic hypotony lead to severe vision loss.
• A comprehensive definition of hypotony should integrate IOP measurements with structural and functional ocular changes.