Trypan blue staining of anteriorly placed zonules in patients with pigment dispersion

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<ul><li><p>achieved with a given microkeratome is mandatory so</p><p>a surgeon will be able to predetermine that if a thicker-than-</p><p>expected flap is created, sufficient residual tissue would remain</p><p>and if that is not the case, the surgeon might consider</p><p>undercorrecting the eye, decreasing the ablation diameter,</p><p>performing photorefractive keratectomy, or implanting a phakic</p><p>intraocular lens.dPerry S. Binder, MD</p><p>Capsule staining techniques</p><p>Marques and coauthors1 described their 3-step</p><p>technique for staining the anterior capsule with</p><p>indocyanine green or trypan blue. They also discussed</p><p>other techniques that have been and are used including</p><p>injecting the dye under an air bubble and injecting the</p><p>dye into an anterior chamber filled with an ophthalmic</p><p>viscosurgical device (OVD).</p><p>There is another, arguably easier technique for cap-</p><p>sule staining that the authors did not mention. After</p><p>the section is made, trypan blue is injected directly</p><p>into the anterior chamber, essentially replacing aque-</p><p>ous. After 60 seconds, the trypan blue is washed out</p><p>with a balanced salt solution and the degree of capsule</p><p>staining is assessed. If staining is sufficient, the opera-</p><p>tion is continued in the usual manner. If staining is</p><p>insufficient, the process is repeated.</p><p>This technique avoids the problems with air</p><p>bubbles and OVDs in determining the correct plane</p><p>and also avoids problems with differential or partial</p><p>staining. The only concern is whether the direct</p><p>exposure to the endothelium is more damaging than</p><p>the techniques discussed by Marques and coauthors.</p><p>However, we know that trypan blue has been used for</p><p>many years to evaluate corneal endothelial cells before</p><p>keratoplasty with very little or no toxicity documented,</p><p>at least not in the concentrations that we use clinically</p><p>for capsule staining.2,3 In addition, we and many of our</p><p>colleagues have been using this simple technique for</p><p>the past 4 years with no detrimental effects. Admit-</p><p>tedly, we can only advocate this technique for trypan</p><p>blue as we have no experience with indocyanine green.</p><p>ALI A. MEARZA, MRCOPHTHAVINASH A. KULKARNI, MRCOPHTH</p><p>Kingston-upon-Thames, United Kingdom</p><p>References1. Marques DM, Marques FF, Osher RH. Three-step tech-</p><p>nique for staining the anterior lens capsule with indocya-</p><p>LETTERS</p><p>2462 J CATARACT REFRACT SURGnine green or trypan blue. J Cataract Refract Surg 2004;30:1316</p><p>2. Georgiadis N, Kardasopoulos A, Bufidis T. The evalua-tion of corneal graft tissue by the use of trypan blue. Oph-thalmologica 1999; 213:811</p><p>3. Singh G, BohnkeM, von-Domarus D, et al. Vital stainingof corneal endothelium. Cornea 1985-86; 4:8091</p><p>Reply: Mearza and Kulkarni are correct in their comments.Along with the techniques mentioned in our paper, it is possible</p><p>to stain the anterior capsule by replacing the aqueous humor</p><p>with trypan blue. However, this technique must be considered</p><p>cautiously because of possible drawbacks. First, the entire</p><p>anterior segment will be stained unnecessarily since only the</p><p>anterior capsule needs to be stained. Second, the anterior</p><p>chamber may be overfilled inadvertently, stressing the zonules</p><p>and leading to migration of dye to the anterior vitreous, with loss</p><p>of red reflex compromising the subsequent steps of the</p><p>procedure (phacoemulsification, cortex aspiration, and intraoc-</p><p>ular lens implantation). Finally, the endothelial cells will be</p><p>exposed to the dye, which is more damaging than exposure to</p><p>an OVD, especially in eyes with a low cell count, although it</p><p>may not be clinically significant in healthy corneas.dFrederico</p><p>F. Marques, MD, Daniela M.V. Marques, MDTrypan blue staining of anteriorlyplaced zonules in patientswith pigment dispersion</p><p>The article by Kelty and coauthors1 highlights the</p><p>seldom-considered finding of anteriorly placed</p><p>zonules. The authors noted staining of the zonules after</p><p>application of indocyanine green (ICG) dye used to</p><p>enhance visualization of the anterior capsule. This is of</p><p>particular relevance in patients having phacoemulsifi-</p><p>cation surgery because of the need for an intact con-</p><p>tinuous curvilinear caspsulorhexis to enable stable</p><p>in-the-bag fixation of the intraocular lens.2</p><p>We have observed anteriorly placed zonules made</p><p>visible following the use of trypan blue dye 0.1%</p><p>(Vision Blue, Dorc International) to stain the anterior</p><p>capsule during cataract surgery in 2 patients with signs</p><p>of pigment dispersion. Moroi et al.3 recently described</p><p>a series of 15 patients with anteriorly placed zonules</p><p>associated with signs of anterior segment pigment</p><p>dispersion. They speculate that contact between the</p><p>zonules and iris pigment epithelium at the pupillary</p><p>ruff and central iris was the cause of pigment release.</p><p>VOL 30, DECEMBER 2004</p></li><li><p>Although often subtle, long, anteriorly inserted</p><p>zonules may be visible on slitlamp biomicroscopy and</p><p>are easily missed. We suspect these zonules may be</p><p>more common than thought. Anteriorly inserted</p><p>zonules should be specifically looked for during pre-</p><p>operative assessment of patients with cataract, partic-</p><p>ularly patients with signs of pigment dispersion in the</p><p>form of corneal endothelial pigment deposits, iris trans-</p><p>illumination defects, and increasedtrabecular meshwork</p><p>pigmentation.</p><p>When anteriorly inserted zonules are noted, con-</p><p>sideration should be given to improving preoperative</p><p>visualization of the zonules with the use of trypan blue</p><p>or ICG staining. The creation of a small capsulorhexis</p><p>to minimize tearing of the zonular insertions and</p><p>zonular free zone. Such a small capsular opening may increase</p><p>the possibility of intraoperative damage to the capsulorhexis,</p><p>difficulty of lens removal, and a postoperative risk for cap-</p><p>sulorhexis contraction or phimosis. It remains unclear whether</p><p>eyes with anteriorly placed zonules have a redistribution</p><p>of the usual number of zonules or an augmented supply,</p><p>some of which are anteriorly located. Accordingly, it is difficult</p><p>to determine whether removal of some zonules during the</p><p>capsulorhexis process would affect structural support. Rather</p><p>than a very small capsulotomy, we restate our recommendation</p><p>to perform a spiral capsulorhexis, starting small and enlarging</p><p>centripedally so an errant tear can be rapidly rescued if a</p><p>peripheral extension begins.</p><p>Chen and coauthors also suggest .a capsular tensionring [CTR] may reduce the potential for peripheral extension of</p><p>the capsulorhexis and zonular dialysis. This implies placement</p><p>of a CTR before capsulorhexis completion. This maneuver</p><p>may carry potential hazards as ring placement through an</p><p>incomplete tear can cause an extension during ring placement</p><p>that might not otherwise occur. Capsular tension rings have</p><p>been a wonderful advance in the treatment of existing zonular</p><p>dialysis or instability; yet, it is unclear whether standard,</p><p>nonfixatable CTRs have an advantage in the prophylaxis of</p><p>future zonular dialysis, unlike the modified fixatable (Cionni)</p><p>CTRs. If there is concern about zonular countertraction for late</p><p>capsulorhexis or phimosis (especially in a small capsulorhexis),</p><p>CTR placement may have prophylactic benefits.dMichael E.</p><p>Snyder, MD</p><p>Postoperative endophthalmitis</p><p>In their article on postoperative endophthalmitis,1</p><p>Sandvig and Dannevig comment that the corner-</p><p>stone of management, as with any infection, includes</p><p>identification of the responsible organisms. In their</p><p>study, the overall frequency of positive cultures was</p><p>75%. They labeled these cases as true endophthalmitis</p><p>and observed the bacterial growth was associated with</p><p>a poor final visual acuity. In the early postoperative</p><p>period, the differential diagnosis between infectious</p><p>and noninfectious inflammatory reaction has to be</p><p>made on clinical signs and symptoms only.2 If in</p><p>doubt, the eye should be treated as if it were infected</p><p>and an anterior chamber and vitreous tap should be</p><p>performed.</p><p>It has been our observation that the presence of</p><p>thick fibrinous exudates extending from the wound</p><p>(main incision or the side-port stab) into the anterior</p><p>chamber and joining those in the center over the</p><p>intraocular lens and pupil, taking the shape of a chem-</p><p>istry retort, strongly indicates an infective cause</p><p>LETTERSplacement of a capsular tension ring may reduce the</p><p>potential for peripheral extension of the capsulorhexis</p><p>and zonular dialysis.</p><p>SIMON D.M. CHEN, FRCOPHTHNICHOLAS GLOVER, FRCOPHTH</p><p>C.K. PATEL, FRCOPHTHOxford, United Kingdom</p><p>References1. Kelty PJ, Snyder ME, Schneider S. Indocyanine green</p><p>staining of anteriorly placed zonules. J Cataract RefractSurg 2003; 29:22292231</p><p>2. Gimbel HV, Neuhann T. Development, advantages, andmethods of the continuous circular capsulorhexis tech-nique. J Cataract Refract Surg 1990; 16:3137</p><p>3. Moroi SE, Lark KK, Sieving PA, et al. Long anteriorzonules and pigment dispersion. Am J Ophthalmol2003; 136:11761178</p><p>Reply: The letter by Chen and coauthors adds to ourreported case of ICG staining of anteriorly placed zonules. In</p><p>their case, they stained anteriorly placed zonules with trypan</p><p>blue. They also comment on the subsequently published article</p><p>by Moroi and coauthors, which describes a series 15 patients</p><p>(29 eyes) with anteriorly placed zonules. While the letter</p><p>reaffirms the important point that ICG or trypan blue vital</p><p>staining can assist in capsulorhexis, some of the comments</p><p>may be confusing.</p><p>As demonstrated in our case and in 13 of 19 eyes</p><p>reported by Moroi and coauthors in which measurements of</p><p>the zonular free zone were taken, this central area measures</p><p>less than 3.0 mm in diameter. The zone is even smaller when</p><p>corneal magnification is taken into account. To reduce the</p><p>chance of a peripheral extension during capsulorhexis creation,</p><p>Chen and coauthors recommend a capsulorhexis within the2463J CATARACT REFRACT SURGVOL 30, DECEMBER 2004</p><p>Trypan blue staining of anteriorly placed zonules in patients with pigment dispersionReferences</p></li></ul>