This is a very easy CataractQuiz™ (click to see the whole series): Once the cataract is removed you see this blue reflex instead of a red reflex. Why?
The blue reflex occurs when trypan blue dye escapes the anterior segment, typically through compromised zonules, and enters the vitreous cavity. Unlike the expected red reflex, where light reflects off the vascular choroid, the dye in the vitreous absorbs the red-orange wavelengths and reflects blue light back toward the surgeon. This creates a challenging surgical environment, as the lack of contrast makes it difficult to visualize the capsular bag and lens fragments. Fortunately, the blue hue is temporary. Trypan blue is not metabolized but is gradually cleared through natural turnover. In most cases, the blue reflex will dissipate within a few days postoperatively. While the patient may experience slightly dimmed or tinted vision initially, the dye is non-toxic to the retina in these concentrations and typically clears completely without further intervention, leaving no long-term staining.
