Sir,

We describe the inadvertent staining of the filtering bleb caused by the use of trypan blue during phacoemulsification in an eye that had previously undergone a trabeculectomy.

Case report

A 28-year-old man with juvenile open-angle glaucoma had undergone trabeculectomy with mitomycin C. The patient presented to us after 6 months with poor vision in his right eye. The patient had a best-corrected visual acuity of 20/200 OD and 20/40 OS. The intraocular pressure (IOP) was 14 mmHg OD and 16 mmHg OS. He had an anterior subcapsular cataract in the right eye (records indicated a shallow anterior chamber in the initial postoperative period), while the left eye lens was clear. Diffuse, elevated, avascular microcystic blebs were noted in both the eyes. The vertical cup-disc diameter ratio was 0.8 : 1 OD and 0.7 : 1 OS.

During cataract surgery, anterior capsular staining was carried out with 0.1 ml of 0.06% trypan blue to enhance the capsule visibility during the capsulorhexis. Staining of the filtering bleb with passage of dye into the bleb was noted. The patient underwent uncomplicated phacoemulsification, followed by implantation of an Acrysof® single piece intraocular lens.

On the first postoperative day, the best-corrected visual acuity was 20/30 OD with an IOP of 14 mmHg. Diffuse staining of the filtering bleb was noted (Figure 1). The staining faded away and was barely visible at 2 weeks follow-up. There was no change in the bleb characteristics as compared to the preoperative status.

Figure 1
figure 1

Trypan blue-stained filtering bleb on the first postoperative day after phacoemulsification.

Full size image

Comments

The present report highlights a benign complication of capsular staining, which is routinely used to aid in the visualization of the anterior capsule during phacoemulsification.1, 2 The surgeon needs to inform the patient preoperatively about the use of the dye and the possibility of transient bleb staining in the postoperative period.

Bleb function may be assessed by slit-lamp examination, by ultrasound biomicroscopy, or indirectly by the control of IOP.3, 4 The inadvertent staining of the bleb as seen in the present case may provide a clue to the adequacy of aqueous drainage through the filter and further studies should be conducted to test this hypothesis.