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- Aqueous humour
- lens and zonules
- intraocular pressure
- angle closure glaucoma
- cataract surgery
- malignant glaucoma
- trypan blue
Trypan blue, originally used as a vital dye to stain devitalised cells,1 is now often used by beginning surgeons learning cataract surgery to stain the anterior capsule before initiating a capsulorexis.2 It is particularly useful when there is a poor red reflex, as in the case of a white cataract or in the presence of a vitreous haemorrhage. The following case illustrates the importance of anticipation when using trypan blue during cataract surgery.
A 66-year-old woman complained of decreased vision in her left eye. Her best-corrected visual acuity was 20/60 due to a 2–3+ nuclear sclerotic cataract. She had an episode of acute angle closure in her fellow eye >6 years earlier, at which time a laser peripheral iridotomy was performed in each eye on successive days. Despite patent peripheral iridotomies, her angles remained narrow, measuring grade 0–1 in all four quadrants bilaterally by the Shaffer angle classification system but without a plateau iris configuration. Her intraocular pressures remained within the normal range during the ensuing years, and serial Humphrey Visual Field studies did not disclose any glaucomatous field defects in either eye. Two months before the current presentation, she underwent phacoemulsification with posterior chamber intraocular lens implantation in her right eye. That surgery was notable for requiring a StabilEyes capsular tension ring (Advanced Medical Optics, Santa Ana, California, USA) to manage intraoperative zonular instability and excessive posterior pressure.
There were no risk factors for zonular dehiscence such as pseudoexfoliation, previous trauma or previous vitrectomy in either eye. Preoperative slit lamp examination was not remarkable for phacodonesis. The axial length of each eye was measured preoperatively to be 22.32 mm by contact A-scan ultrasonography.
Cataract extraction in her left eye was performed under topical anaesthesia from a temporal position. Preservative-free Lidocaine 1% was injected intracamerally through an inferior 1 mm side-port …