Background

A continuous, circular capsulorhexis of the anterior lens capsule is commonly performed in phaco-emulsification and other cataract surgical procedures, to safely allow manipulations within the capsular bag during surgery. To visualize the capsular defect during the performance of a capsulorhexis, most often the 'red fundus reflex' produced by the co-axial light of an operating microscope, can be used. When retroillumination is absent, for example with dense cataracts, heavily pigmented fundi or a combination of both, it may be difficult to discriminate the anterior capsule from the underlying lens tissue. Improper visualization of the capsule may result in an incomplete capsulorhexis, which carries a greater risk of radial capsular tears toward or beyond the equator of the lens, and associated complications.

To visualize the outline of the capsulorhexis during surgery, the use of side-illumination, subcapsular injection of fluorescein, haemocoloration of the capsule with autologous blood, and staining of the capsule with a combination of gentian violet 0.01% and methylene blue 0.1% have been advocated. The first three techniques may be relatively time consuming to perform, they require adjustment of the surgical technique, or preoperative preparation of a haemoderivate. With the fourth technique, postoperative corneal edema was found in some cases, that may have resulted from potential endothelial toxicity of (one of) the dyes.

As an alternative, the anterior capsule may be stained with a single vital dye, trypan blue or indocyanine green, by which the capsulorhexis can be visualized in the absence of a red fundus reflex, but that does not affect the endothelium.

Product

In 1997, a panel of 45 vital dyes was evaluated by the Netherlands Institute for Innovative Ocular Surgery to stain the anterior lens capsule, to facilitate the visualization of the capsulorhexis in mature cataract surgery. From this series of dyes, trypan blue was chosen, because it was most effective in a relatively low concentration, it was know to for its biocompatibility with the corneal endothelium, and it had been used intraocularly before without side-effects.

Trypan blue is now produced for intraocular use as 'VisionBlue' by D.O.R.C. International b.v., Scheijdelveweg 2, 3214 VN Zuidland, Nederland, tel: 31 (0)181 458080, fax: 31 (0)181 458090, e-mail: mailto@dorc.nl.

Surgical technique and Results

Staining of the anterior lens capsule with trypan blue facilitates the visualization of the capsulorhexis, by creating a contrast between the blue stained capsule and the non-stained underlying lens mass.

Clinics

VisionBlue is currently used worldwide.

Literature

In 1998, it became apparent that in 1997 and 1998, various dyes had been evaluated by different scientific groups, for example methylene blue (dr Asis Vainer and coworkers in Spain), indocyanine green (professor Horiguchi and coworkers in Japan), and gentian violet (dr Moustafa and coworkers in Egypt).

• Hoffer KJ, McFarland JE: Intracameral subcapsular fluorescein staining for improved visualization during capsulorhexis in mature cataracts (letter). J Cataract Refract Surg 1993;19:566.
• Asis Vainer O, Ruíz Pérez A: Research on corneal toxicity in capsular dye. ASCRS symposium on cataract, iol and refractive surgery, 1998, abstract no. 124.
• Horiguchi M, Miyake K, Ohta I, Ito Y: Staining of the lens capsule for circular continuous capsulorrhexis in eyes with white cataract. Arch Ophthalmol 1998;116:535-537
• Gamal Eldin SA, el Mehelmy EM, el Shazli EM, Mostafa YM: Experimental staining of the anterior lens capsule in albino rabbits. J Cataract Refract Surg 1999;25:1289-294
• Melles GRJ, de Waard PWT, Pameijer JH, Beekhuis WH: Trypan blue capsule staining to visualize the capsulorhexis in cataract surgery. J Cataract Refract Surg 1999;25:7-9.
• Melles GRJ, de Waard PWT, Pameijer JH, Beekhuis WH: Staining the lens capsule with trypan blue for visualizing capsulorhexis in surgery of mature cataracts. Klin Monatsbl Augenheilkd 1999;215:342-344.