We report a case of inadvertent staining of the vitreous with Trypan Blue during cataract surgery.

We performed cataract surgery in a 44-year-old male patient on an eye with mature cataract. Preoperatively, he had no zonular weakness or lens subluxation. We used trypan blue to stain the anterior capsule to facilitate capsulorhexis. We observed zonular weakness during surgery. During phacoemulsification, the dye entered into the vitreous cavity through the area of zonular weakness and a sudden loss of the red fundus reflex developed. However, we did not perform any specific procedure to correct the problem and finished phacoemulsification and intraocular lens insertion. After surgery, slit lamp examination showed a blue fundal glow, which persisted for 1 week. As expected, the patient's BCVA was better than before the operation.

Use of trypan blue is relatively safe for use in cataract surgery. But to use trypan blue or other dye during cataract surgery, it is necessary to have careful pre operative ocular examination. And if some risk factors like zonular weakness or lens subluxation exists, more caution during surgery is needed.