Oblique illumination and trypan blue to enhance visualization through corneal scars in cataract surgery

Abstract

Visibility of the iris, capsule, and lens may be severely limited during cataract surgery in patients with corneal opacities. In such cases, use of the standard coaxial lighting found on most operating microscopes may hinder the surgeon due to backscatter and reflection of light from the cornea. In this article, we describe the use of an oblique light source in combination with 0.1% trypan blue to improve visualization of the anterior chamber and anterior lens capsule on a patient with severe corneal scarring. A 64-year-old male with chronic angle closure glaucoma and extensive corneal scarring secondary to previous trachoma and HSV-1 infections presented with a dense nuclear sclerotic cataract and posterior synechiae in his left eye. His preoperative corrected distance visual acuity (CDVA) was 20/400 wearing +2.00+4.00 × 164. The patient subsequently underwent cataract surgery. Trypan blue dye was used to stain the anterior capsule followed by viscodilation. The capsulorrhexis was initiated, but then hindered by poor visibility through the corneal scars (Fig. 1) . After completing 75% of the capsulorrhexis, a small portion of capsule was pulled off, leaving the remaining capsulorrhexis discontinuous. Corneal scarring impeded visualization to the point that the remaining capsule could not be seen to complete the rhexis. The overhead coaxial light from the microscope as well as operating room lights were then turned off and a 20 gauge fibre-optic light source from an endocyclophotocoagulation device (EndoOptiks, Little Silver, N.J.) was used to provide oblique transcorneal illumination. An assistant oriented the probe perpendicular to the cornea and held it just above the surface in a peripheral location with relatively little scarring. The camera and laser components of the probe were not used. Positioning was adjusted as required to provide optimal visualization of the capsule and the capsulorrhexis was completed without difficulty (Fig. 2) . Hydrodissection, phacoemulsification, cortex removal, and lens insertion were then carried out under oblique illumination.Fig. 2Under oblique illumination, visualization improves and the capsulorrhexis can be completed.View Large Image Figure ViewerDownload (PPT) The patient's uncorrected distance visual acuity (UDVA) at 1 week postoperative was 20/80-1 and is expected to improve with updated glasses. The successful use of 0.1% trypan blue with conventional coaxial illumination alone has been described as a safe and effective way to enhance visualization for cataract surgery in patients with corneal opacities, even though in some cases staining alone may not provide adequate visualization.1Jacobs D.S. Cox T.A. Wagoner M.D. Ariyasu R.G. Karp C.L. Capsule staining as an adjunct to cataract surgery: a report from the American Academy of Ophthalmology.Ophthalmology. 2006; 113: 707-713Abstract Full Text Full Text PDF PubMed Scopus (72) Google Scholar, 2Ozturk F. Osher R.H. Capsular staining: recent developments.Curr Opin Ophthalmol. 2006; 17: 42-44Crossref PubMed Scopus (21) Google Scholar, 3Bhartiya P. Sharma N. Ray M. Sinha R. Vajpayee R.B. Trypan blue assisted phacoemulsification in corneal opacities.Br J Ophthalmol. 2002; 86: 857-859Crossref PubMed Scopus (51) Google Scholar, 4Titiyal J.S. Sinha R. Sharma N. Vajpayee R.B. Dye-assisted small incision cataract surgery in eyes with cataract and coexisting corneal opacity.Eye. 2006; 20: 386-388Crossref PubMed Scopus (11) Google Scholar Farjo et al.5Farjo A.A. Meyer R.F. Farjo Q.A. Phacoemulsification in eyes with corneal opacification.J Cataract Refract Surg. 2003; 29: 242-245Abstract Full Text Full Text PDF PubMed Scopus (11) Google Scholar described the use of a noninvasive fibre-optic light source to provide oblique illumination without capsular staining, whereas Nishimura et al.6Nishimura A. Kobayashi A. Segawa Y. Sugiyama K. Endoillumination-assisted cataract surgery in a patient with corneal opacity.J Cataract Refract Surg. 2003; 29: 2277-2280Abstract Full Text Full Text PDF PubMed Scopus (31) Google Scholar used a similar technique with indocyanine green staining to carry out the capsulorrhexis, and then inserted the light source into the eye through a corneal paracentesis to complete phacoemulsification. We describe the use of noninvasive oblique fiber optic illumination in combination with trypan blue dye to carry out an entire cataract surgery. This approach is safe, effective, and provides excellent visibility during cataract surgery complicated by corneal opacification. It can be carried out with minimal additional resources (a light source and trypan blue dye) and is noninvasive. Our technique thus provides the ophthalmic surgeon with an effective approach to the patient with a corneal opacity—combined use of 0.1% trypan blue with noninvasive oblique illumination greatly enhances the visualization of the anterior chamber in the presence of a corneal opacity, whereas staining of the peripheral anterior capsule greatly facilitates lens removal during phacoemulsification.