Journal of Postgraduate Medicine
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Year : 2022  |  Volume : 68  |  Issue : 2  |  Page : 100-101  

Post-trabeculectomy early bleb localization mimicking a 'ring of steel'

S Choudhary, M Kaur, SS Pandav, S Kaushik 
 Department of Ophthalmology, Advanced Eye Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India

Correspondence Address:
S Kaushik
Department of Ophthalmology, Advanced Eye Centre, Post Graduate Institute of Medical Education and Research, Chandigarh


A 54-year-old-man underwent trabeculectomy with mitomycin-C (0.02%). At 4-week follow-up, there was an elevated, well-circumscribed bleb with raised intra-ocular pressure (IOP) of 32-mmHg, with a classic “ring of steel” appearance, typically seen in a tenon's cyst. A sub-tenon needle revision re-established aqueous flow. Two weeks later, the IOP was 8-mmHg without any anti-glaucoma medications. A diffuse well formed bleb was noted. Careful ocular examination helps to identify early post-operative localized bleb that may appear like a “ring of steel” but can be managed by needling, unlike a tenon's cyst, which would require more extensive intervention.

How to cite this article:
Choudhary S, Kaur M, Pandav S S, Kaushik S. Post-trabeculectomy early bleb localization mimicking a 'ring of steel'.J Postgrad Med 2022;68:100-101

How to cite this URL:
Choudhary S, Kaur M, Pandav S S, Kaushik S. Post-trabeculectomy early bleb localization mimicking a 'ring of steel'. J Postgrad Med [serial online] 2022 [cited 2022 Sep 26 ];68:100-101
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Successful trabeculectomy surgery is the product of the surgery itself and, more importantly, of a proper nurturing of the bleb. The fibrous reaction at the surgical site in the post-operative period can limit the scope of the aqueous's posterior drainage, resulting in a cystic bleb surrounded by a ring of fibrous or scar tissue commonly known as the “ring of steel.”[1] This obstruction to posterior drainage can lead to an overhanging bleb due to the push faced by the limbal conjunctiva, ultimately putting the bleb at risk of failure. If left unrecognized or untreated in its early course, a ring of steel will inevitably require a bleb revision with conjunctival advancement surgery.

 Grand Round Case

A 54-years old male patient presented with raised intraocular pressure in both eyes. On clinical examination, his best-corrected visual acuity was 6/9 in both the eyes, and intraocular pressure (IOP) on the Goldmann applanation tonometer was 32 mmHg in the right eye and 24 mmHg in the left eye on topical brinzolamide (1.0% w/v), timolol (0.5% w/v), travoprost (0.004%) and brimonidine (0.2% w/v) along with systemic tablet acetazolamide 250 mg thrice a day. On gonioscopy examination, prominent iris processes with high iris insertion and concave iris configuration were found with total cupping in both the eyes. He was diagnosed as a case of juvenile open-angle glaucoma and underwent right eye trabeculectomy augmented with intra-operative mitomycin-C (sponges soaked in 0.02% solution and applied for 2 minutes in the subtenon's space).

The patient developed an elevated, well-circumscribed, and thin-walled bleb with fibrosis around the bleb margin at three weeks follow-up, giving it a typical “ring of steel” appearance [arrow, [Figure 1]a]. The sub-conjunctival fluid indicated a localized bleb [star, [Figure 1]a].{Figure 1}

What to do next?

The appearance of a “ring of steel” in the post-operative period indicates intense scar tissue around the bleb, limiting the posterior drainage of the aqueous and thus resulting in an elevated and well-circumscribed bleb. It is vital to intervene surgically at this stage to rescue and nurture the bleb. A bleb revision surgery with conjunctival advancement surgery is a commonly thought of procedure in such cases. Still, in the present case, bleb needling was done at slit lamp through subconjunctival space to break the early fibrosis around the bleb. A diffuse bleb was formed at the end of needling. Subconjunctival 0.1 mL of injection 5-fluorouracil (250 mg/5 mL) was injected to prevent extensive fibrosis at the end of the procedure. An IOP of 6 mmHg was noted immediately after needling. A diffuse well formed bleb was noted on follow-up visit [Figure 1]b. Extensive fibrosis can be the cause of failure of trabeculectomy, and injection 5-fluorouracil is helpful in preventing it.

The post-procedure IOP at two weeks follow-up was noted to be 8.0 mmHg without anti-glaucoma medications. The “ring of steel” phenomenon, if recognized in time, can be well managed by early needling.

Method of bleb needling on slit lamp

  1. Ask the patient to sit comfortably and instill topical proparacaine (0.5% w/v)
  2. Take a 26G needle mounted on a 2 cc syringe for ease of holding, and bend it till about 45-degrees near the hub
  3. Instruct the patient to look downwards, insert the needle to the subconjunctival plane near the bleb site, move it in swiping motion below the scleral flap and notice the resistance encountered. At the same time, the fibrous bands are cut with the needle
  4. The endpoint for the procedure is when one notices a well-formed diffuse bleb
  5. Subconjunctival 0.1 mL of 5-fluorouracil (250 mg/5 mL) must be injected away from the bleb site near the superior fornix to prevent extensive scarring and aid posterior drainage of the aqueous.

Take home message

“Ring of steel” is a cause of bleb failure, necessitating careful examination and management to prevent bleb failure after trabeculectomy. Early recognition and intervention might help save patients from undergoing a repeat major surgical procedure.

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Conflicts of interest

There are no conflicts of interest.


1Jones E, Clarke J, Khaw PT. Recent advances in trabeculectomy technique. Curr Opin Ophthalmol 2005;16:107-13.

Monday, September 26, 2022
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