Intraoperative triamcinolone acetonide injection is currently very popular among vitreoretinal surgeons for visualizing vitreous and posterior hyaloid during pars plana vitrectomy.1 It is also used as an adjunct in anterior segment surgery, and its use of intracameral injection is helpful to visualize vitreous prolapsed into anterior chamber during complicated phacoemulsification surgery.2,3
Interaction of intraocular lens (IOL) materials with several dyes (fluorescein sodium, trypan blue, indocyanine green)4,5 and silicone oil6–8 has been investigated. To our knowledge, interaction of triamcinolone with IOL materials has not been studied before. In this experimental study, we aimed to evaluate the adherence of triamcinolone acetonide to various IOL materials.
MATERIALS AND METHODS
Four IOLs of 4 materials were tested in vitro to evaluate triamcinolone acetonide adherence to the IOL optic. Single-piece poly(methyl methacrylate) (PMMA) IOL (Crystal Type 01, Alcon Laboratories), 3-piece foldable silicone optic IOL (SILICON 411, Intraocular Optical International-IOI), 3-piece hydrophobic acrylic IOL (Acrysof MA60BM, Alcon Laboratories), and single-piece hydrophilic acrylic IOL (Alpha 60 E, Eurocrystal) were the tested IOL materials. A total of 16 IOLs comprised the study group.
Each IOL was immersed in 40 mg/mL commercially available triamcinolone acetonide (Kenacort-A, Bristol-Myers Squibb) for 15 minutes. Each lens was then bathed in a balanced salt solution (BSS, Alcon Laboratories) for another 15 minutes. Afterward, each lens optic was examined under a light microscope (Olympus BX51) and digital images were taken with a digital color video camera (Olympus DP70). Image analysis was performed with Mediscope software (Dokuz Eylül University Biomedical Technology). Two-dimensional Fourier transform was performed to find the image frequencies. Low-pass frequencies were discarded by a high-pass filter operation. Filtered image reconstruction was performed by 2-dimensional inverse fast-Fourier transform, and pixel values of the images were enhanced by image-intensity histogram correction. Black-and-white images were obtained by threshold operation. Coloring the black-and-white images resulted in separated regions. Finally, pixel counting of the selected regions was performed by using image analysis software. The area of triamcinolone coverage was calculated in terms of pixels. The ratio of optic area covered with triamcinolone to the overall optic area was determined as the percentage of triamcinolone coverage.
The Mann-Whitney test was used for statistical analysis. P values less than 0.05 were considered statistically significant.
The percentages of triamcinolone coverage of each IOL and mean triamcinolone coverage for each group are shown in Table 1A. Figure 1, A and B depicts an example of triamcinolone adherence. The percentage of triamcinolone coverage was compared among the groups (Table 1B). Statistical comparison demonstrated that triamcinolone acetonide adherence to hydrophilic acrylic IOLs was statistically significant when compared with adherence to other IOL materials.
Triamcinolone acetonide is a minimally water-soluble steroid injected in a suspension form, and its intravitreal injection was first described by Tano and coauthors9 in 1980. However, Peyman and coauthors1 popularized its intraoperative use during pars plana vitrectomy to better identify cortical vitreous and posterior hyaloid and achieve a complete vitrectomy. Recently, Burk et al.2 used triamcinolone acetonide to stain prolapsed vitreous and facilitate its removal from the anterior chamber during complicated phacoemulsification surgery.
There is little information regarding the residence time of triamcinolone acetonide in the anterior chamber and vitreous after intravitreal injection. Beer et al.,10 using direct aqueous sampling, calculated the mean elimination half-life of a single 4 mg intravitreal injection of triamcinolone acetonide in the nonvitrectomized eye and vitrectomized eye to be 18.6 days and 3.2 days, respectively. Thus, 4 mg triamcinolone acetonide is eliminated in 5 half-lives or 93 ± 28 days in nonvitrectomized eyes. Mason and coauthors11 determined the intravitreal concentration and clearance of triamcinolone acetonide in 6 eyes that had pars plana vitrectomy at various intervals after intravitreal injection of 4 mg triamcinolone acetonide and analyzed undiluted specimens of vitreous overlying the macula and of aqueous humor. These investigators concluded that the intravitreal concentration of triamcinolone acetonide was detectable up to 2.75 months after a single 4 mg injection in nonvitrectomized eyes.
Adhesion of triamcinolone acetonide to the IOL optic may decrease visualization of the fundus intraoperatively by obscuring the visual axis. Furthermore, this may be more troublesome in the patients in whom posterior capsule is not intact. Moreover, if facedown position is required postoperatively, this adhesion may result in temporary decreased visual acuity and impair fundus visualization. We suggest that it is worthwhile to investigate the interaction of triamcinolone acetonide with IOL materials.
We tested the interaction of various IOLs with several intraoperatively used materials. Öner et al.6 evaluated 4 groups of IOLs (single-piece PMMA, monoblock hydrophilic acrylic, monoblock hydrophobic acrylic, and 3-piece silicone optic IOLs) to determine the percentage of silicone oil (1000, 1300, and 5000 centistokes) adherence to these lenses. Silicone IOLs had the highest percentage of silicone oil coverage (79.9%), whereas hydrophilic acrylic (7.8%) and hydrophobic acrylic (15.1%) lenses had less coverage. The concentration of the silicone oil had no effect on the percentage of silicone oil coverage.
Ozbek et al.4 determined the staining characteristics of various IOLs (PMMA, silicone, 3-piece hydrophobic acrylic, single-piece hydrophobic acrylic, and single-piece hydrophilic acrylic) in different dyes (trypan blue, indocyanine green, and fluorescein sodium) at different concentrations and showed that hydrophilic acrylic lenses demonstrated marked dye uptake and that washout might take some time.
In this study, we demonstrated that triamcinolone acetonide adheres better to hydrophilic acrylic lenses than to hydrophobic, silicone, and PMMA IOLs. Most currently available hydrophilic acrylic lenses have a water content ranging from 18% to 28%, and the water content of hydrophilic IOL tested in this study is 25%. It is probable that this lens may not represent all hydrophilic acrylic IOLs available in the market. In light of our findings, adherence of triamcinolone acetonide to hydrophilic acrylic IOLs should be considered because it may have clinical implications, such as limitation of fundus view and temporary decreased visual acuity.
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