Trypan-blue-assisted posterior capsule plaque removal

CORRESPONDENCE

Table 1. Time kill data of endophthalmitis bacterial isolates to ciprofloxacin, ofloxacin, and povidone–iodine. Time (H) to 100% Kill of All Bacterial Isolates Endophthalmitis Isolates Coagulase-negative Staphylococcus

Number

Ciprofloxacin

Ofloxacin

Povidone–Iodine

5

1

1

1

5

⬎24

⬎24

4

Fluoroquinolone susceptible Coagulase-negative Staphylococcus Fluoroquinolone resistant Staphylococcus aureus, FQ susceptible

5

1

1

1

Staphylococcus aureus, FQ resistant

5

⬎24

⬎24

6

Enterococcus species

5

24

24

24

Streptococcus pneumoniae

5

2

2

1

Streptococcus viridans

5

6

8

1

Bacillus species

5

1

1

2

Pseudomonas aeruginosa

2

1

1

1

Serratia marcescens

2

1

1

24

FQ ⫽ fluoroquinolone

Staphylococcus, S aureus, and P aeruginosa at 1 hour. Both fluoroquinolones were equally effective and better than povidone–iodine against S marcescens and Bacillus species. Povidone–iodine was more effective than ciprofloxacin and ofloxacin against S viridans and S pneumoniae. Ciprofloxacin was more effective than ofloxacin for S viridans. Neither fluoroquinolone was effective against the fluoroquinolone-resistant coagulase-negative Staphylococcus and S aureus, while povidone–iodine was effective at 4 and 6 hours, respectively. None of the agents was effective against the Enterococcus species by 24 hours. Our in vitro study suggests that the combination of a fluoroquinolone antibiotic agent with povidone–iodine is a complementary combination for surgical prophylaxis. Fluoroquinolone-resistant bacterial isolates were covered by povidone–iodine, and the fluoroquinolones were effective against S marcescens and Bacillus species that were less susceptible to povidone–iodine. The fluoroquinolone resistance seen in the Staphylococcus species does not appear to be overridden by sustained exposure to the fluoroquinolones. Overall, the agents showed a fairly strong ability to eliminate known endophthalmitis-causing strains of bacteria. One area of concern was the complete failure of any agent to eradicate Enterococcus after 24 hours of bathing in the antibiotic solution. The results of this study are limited clinically by the inability to take into account the actual concentration of 916

each agent that is present on the ocular surface and in the anterior chamber with topical application. Further testing with other agents, including the new-generation fluoroquinolones, would allow us to better assess the best combination of prophylactic agents to prevent endophthalmitis. MICHAEL R. KEVERLINE, MD REGIS P. KOWALSKI, MASCP DEEPINDER K. DHALIWAL, MD Pittsburgh, Pennsylvania, USA

References 1. Goldstein MH, Kowalski RP, Gordon YJ. Emerging fluoroquinolone resistance in bacterial keratitis: a five year review. Ophthalmology 1999; 106:1313–1318 2. Chaudhry NA, Flynn HW, Murray TG, et al. Emerging ciprofloxacin-resistant Pseudomonas aeruginosa. Am J Ophthalmol 1999; 128:509 –510

Trypan-Blue-Assisted Posterior Capsule Plaque Removal

T

rypan blue dye is being used for anterior capsule staining to facilitate performance of the capsulorhexis in the absence of the red fundus reflex.1 Its role in the learning of various critical steps of phacoemulsification has been suggested.2 We recently described another capsular dye, indocyanine green, that unmasks anterior capsule fibrosis.3 We now describe our experience using

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trypan blue 0.1% in a case of pediatric cataract surgery in which it preferentially stained and highlighted the posterior capsule plaque more than the posterior capsule, which helped the surgeon to remove the plaque easily and completely without damaging the posterior capsule. Cataract surgery with intraocular lens implantation (IOL) was planned in an 8-year-old child with a unilateral developmental cataract in his right eye. After uneventful phacoaspiration, a fibrous plaque was observed on the posterior capsule. Under an air bubble in the anterior chamber, 0.5 mL of trypan blue 0.1% (Vision Blue, DORC) was injected into the capsular bag. After 30 seconds, the dye was washed out with the irrigating solution (fortified balanced salt solution [BSS Plus威]). The trypan blue intensely stained the margins of the posterior capsule plaque (Figure 1). The white, thickened, and fibrotic areas of plaque were more intensely stained than the thinner areas, so the morphology of the plaque was delineated against the stained posterior capsule. Posterior capsule plaque peeling was initiated with a bent 26-gauge needle and completed with the capsulorhexis forceps. The integrity of the posterior capsule was not jeopardized. The capsular bag was then filled with sodium hyaluronate 1.4% (Healon GV威), and a foldable IOL (AcrySof威) was implanted safely in the bag. The posterior capsule plaques may jeopardize the visual acuity, decrease contrast sensitivity, and increase glare postoperatively. It demands careful dissection of the posterior capsule plaque without disturbing the integrity of the posterior capsule or causing an uncontrolled tear.

Our case demonstrates the ability of trypan blue to highlight the posterior capsule plaque intensely, thus enhancing its visualization compared to the rest of the posterior capsule; this aids in the complete removal of the plaque. Our observation of staining posterior capsule plaques may also be applied to the mature senile cataract with posterior capsule plaques, which are more commonly found in the developing world.4 Although thin posterior capsule plaques may be amenable to future neodymium:YAG capsulotomy, dense fibrotic plaques may not. Dye-enhanced removal of the posterior capsule plaque in such cases will ensure complete removal intraoperatively. In the event of an inadvertent uncontrolled tear in the posterior capsule, the presence of the stained posterior capsule may help redirect the tear and achieve a central circular posterior capsulorhexis. NAMRATA SHARMA, MD VISHAL GUPTA, MD RASIK B. VAJPAYEE, MBBS, MS New Delhi, India

References 1. Melles GRJ, de Waard PWT, Pameyer JH, Beekhuis WH. Trypan blue capsule staining to visualize the capsulorhexis in cataract surgery. J Cataract Refract Surg 1999; 25:7–9 2. Werner L, Pandey SK, Gomez ME, et al. Dye-enhanced cataract surgery. Part 2: learning critical steps of phacoemulsification. J Cataract Refract Surg 2000; 26:1060 – 1065 3. Sharma N, Pangtey MS, Dada VK. Experience with indocyanine green dye. (letter) J Cataract Refract Surg 2001; 27:1342 4. Peng Q, Hennig A, Vasavada AR, Apple DJ. Posterior capsular plaque: a common feature of cataract surgery in the developing world. Am J Ophthalmol 1998; 125:621– 626

Topical Sodium Hyaluronate Before LASIK

E

Figure 1. (Sharma) Trypan-blue-assisted posterior plaque peeling.

pithelial defects are usually regarded as a minor problem in laser in situ keratomileusis (LASIK), occurring in a small percentage of patients (less than 3% according to Machat1) and usually early in the surgical learning curve. However, in our daily LASIK practice at Ultralase, epithelial abrasions are a significant nuisance even to experienced surgeons. Small abrasions, often lo-

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