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To evaluate the impact of tumor burden and chemotherapy dose scheduling on the response to subconjunctival carboplatin treatment in a murine transgenic retinoblastoma model. Methods: Eighty simian virus 40 T antigen-positive mice were treated at age 5 or 10 weeks. Six control animals received placebo treatment. Twenty-four 5-week-old mice received 6 subconjunctival carboplatin injections at doses of 30 to 300 µg delivered at 72-hour intervals. Fifty 10week-old mice received either 6 or 12 subconjunctival carboplatin injections at doses of 30 to 300 µg delivered at 72-hour intervals. All eyes were obtained at age 16 weeks for histopathologic examination. Eyes were graded as positive if any tumor was present. Results: All simian virus 40 T antigen-positive control eyes contained large tumor foci throughout the retina.

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To determine the time course and extent of tumor reduction associated with systemic chemotherapy or external beam radiotherapy (EBRT) in the treatment of advanced intraocular retinoblastoma. Methods: Retrospective review of children with Reese-Ellsworth stages IV and V retinoblastoma undergoing primary globe-conserving therapy with either systemic chemoreduction or EBRT. Study variables were recorded at baseline, at monthly intervals for the first 6 months, and at 12 months after the initiation of treatment. Tumor volumes were calculated using basal area and height values determined by ultrasonography, physical examination, and fundus photographic review. Main Outcome Measures: Outcome measures included tumor volume, tumor reduction, regression pattern, treatment-related complications, metastases, and survival. Results: Twenty-six eyes of 26 patients were evaluated for tumor response; 18 patients were treated with systemic chemotherapy and 8 patients were treated with EBRT. Median follow-up was 36 months. A mean 68% reduction in tumor volume occurred after 1 cycle of chemotherapy compared with a 12% reduction at a similar time point (1 month) after initiation of EBRT (PϽ.004). There was no statistically significant difference in tumor volume reduction between treatment modalities at the 12-month follow-up visit. Both systemic chemoreduction and EBRT achieved 100% globe conservation and 100% patient survival in this series. Conclusions: Retinoblastoma reduction exhibits a differential time course based on the applied primary treatment. Systemic chemotherapy is associated with earlier tumor reduction than EBRT.

To determine the orbital tolerance of a microporous implant fitted with an integrated stainless steel post and the enhanced motility associated with magnetic coupling of the prosthetic and the implant in a rabbit model.Methods: Six New Zealand white rabbits underwent primary enucleation with implantation of a 12-mm microporous polyethylene implant with a 2ϫ3-mm stainless steel post embedded flush with the anterior surface. At 1 month, the rabbits were fitted with an external prosthesis containing two 1-mm circular rare earth dental magnets embedded at 0.5 mm off the midline (right and left of center at the horizon). Magnetic coupling forces were determined with a hanging block technique.Results: No evidence of toxicity was observed in asso-ciation with this integrated ocular implant. Magnetic coupling forces were noted maximally at 0.47 N. Clinical grading of motility documented enhancement in lateral excursion when compared with nonintegrated controls. Conclusion:Magnetically integrated microporous implants achieve excellent enhancement of motility without evidence of complications in this rabbit model.Clinical Relevance: This study establishes a framework for the clinical evaluation of a magnetically integrated implant that may enhance prosthetic motility without requiring direct mechanical coupling of the implant to the prosthesis.