A histological analysis of lens capsules stained with trypan blue for capsulorrhexis in phacoemulsification cataract surgery

Abstract

Purpose Staining of anterior lens capsules with dye to facilitate completion of continuous curvilinear capsulorrhexis is now being used more frequently in phacoemulsification of white and mature cataracts with poor red reflexes. This study examined the histological characteristics of anterior lens capsules stained with trypan blue. The layer(s) of the lens capsule that stained with dye and the extent of accumulation of dye in these layers of the lens capsule were determined. To the best of our knowledge this has not been described before. Methods A series of 10 stained lens capsules were analysed histologically. The dye used in this study consisted of a standard sterile, noninflammatory, nonpyrogenic, 2 ml solution containing 0.6 mg/ml of trypan blue. Following capsulorrhexis, samples were sent to the laboratory for histological analysis. Frozen sections (8 lm) were prepared and examined with the light microscope. All 10 capsules were cut by frozen section to preserve trypan blue staining (which would be leached by processing) and then subjected to immunohistochemistry for collagen IV. Immunohistochemical analysis using markers for type IV collagen were done on formalinfixed specimens for morphological comparison with the frozen sections. A counterstain highlighted the epithelium. Results Continuous curvilinear capsulorrhexis was successfully and easily completed in all cases without any complications. Frozen section analysis using light microscopy demonstrated accumulation of trypan blue dye in the basement membrane of the lens capsule. Staining was concentrated in the portion of the membrane adjacent to the lens epithelium. The lens epithelium could not be clearly identified on the frozen sections. Consequently, immunohistochemical analysis with markers for type IV collagen was performed. A counterstain highlighted the epithelium. This confirmed that the layer staining with trypan blue was the basement membrane, a consistent feature on all the specimens. Conclusions Trypan blue selectively stains the basement membrane of the anterior lens capsule. There is a concentration of dye in the basement membrane adjacent to the lens epithelial cell layer. The lens cortex does not appear clinically to stain with trypan blue. This enables surgeons to distinguish the lens capsule from the cortex and provides sufficient contrast for successful completion of continuous curvilinear capsulorrhexis during cataract surgery.

Effect of trypan blue staining on the density and viability of lens epithelial cells in white cataract

“…This allows good visualization of the peripheral anterior rim of the capsulorhexis, reducing the incidence of radial tears toward and beyond the equator. A report 19 of the histologic analysis of lens capsules stained with trypan blue found staining mostly in the basement membrane adjacent to the epithelial layer of the lens capsule with minimal laminar staining in the superficial basement membrane. In another report, 20 the authors compared anterior capsule electron microscopy findings with and without trypan blue stain and observed a focally ragged and irregular outer limit of the capsule with trypan blue when compared with untreated capsules.…”

A prospective study on trypan blue capsule staining under air vs under viscoelastic

“…It has been confirmed histologically that trypan blue selectively stains the basement membrane of the anterior lens capsule. 17 Originally, Melles et al 9 stained the anterior capsule under an air bubble. Yetik et al 11 advocated trypan blue capsule staining under a dispersive viscoelastic, claiming that staining with an air bubble resulted in longer surgery and more oedematous cornea in the early postoperative period.…”

Trypan blue dye for anterior segment surgeries

“…2,5,48,49 The effect of TB on lens epithelial cells has been tested using different techniques. 50,51 Although in vitro studies found no effect on the viability of LECs at concentrations ranging from 0.025 to 5.0 mg/ml, 52 Nanavaty et al 11 reported a significant decrease in LEC density covering the anterior lens capsule after the use of 0.0125% TB for 30 s compared with that of untreated eyes. Portes et al 53 found LEC death with 0.1% TB which supports that staining with TB can help reduce the incidence of posterior capsule opacification.…”