Is very blurry vision normal after trabeculectomy?

What's normal

Trabeculectomy deliberately makes fluid leave the eye more easily, so eye pressure often drops a lot at first. Some people describe the eye as feeling soft, and vision as much blurrier than expected, sometimes with distorted or wavy images. This is why the Glaucoma Research Foundation says the eye doctor needs to check the eye pressure within a few days after surgery.

In many cases the surgeon simply watches it, because the scleral flap tightens as it heals. StatPearls defines ocular hypotony as an average intraocular pressure of 5 mm Hg or less measured at least three times, and notes some sources use less than 6.5 mm Hg. StatPearls reports a five year probability of hypotony of 7.7 percent after trabeculectomy with mitomycin C, while EyeWiki reports hypotony in about 0.9 percent in the CIGTS study, so the numbers vary a lot with technique and definition.

Low pressure is most common in the first days to weeks and often improves. Persistent low pressure is a reason for a bleb revision discussion.

When it stops being normal

Report new or worsening blur, distorted or wavy central vision, or a soft feeling eye to your surgeon promptly. StatPearls says patients with hypotony may be symptom free or may notice vision loss or distortion in images, and lists a shallow front chamber, choroidal detachment, hypotony maculopathy with macular striae, corneal folds, and optic disc swelling as signs. EyeWiki reports a shallow or flat front chamber in about 13 percent in CIGTS and about 10 percent in the Tube Versus Trabeculectomy study.

Do not try to judge your own eye pressure by feel and never stop or start a drop on your own to correct it. StatPearls notes that several authors have shown the effects of hypotony can reverse after successful treatment, including bleb revision, which is one reason getting seen early matters.