Effective transscleral delivery of two retinal anti-angiogenic molecules: carboxyamido-triazole (CAI) and 2-methoxyestradiol (2ME2).

PURPOSE: To evaluate the human transscleral diffusion and intravitreal delivery of carboxyamido-triazole (CAI) and 2-Methoxyestradiol (2ME2). METHODS: The transscleral diffusion of two retinal antiangiogenic molecules, CAI and 2ME2, was measured in vitro to assess their potential transscleral delivery. Varying concentrations and different solvents of CAI and 2ME2 were placed in the upper compartment of a two-chamber acrylic perfusion apparatus, on the episcleral side of the sclera obtained from human donor eyes. Samples were taken from the lower compartment (uveal side) for up to 24 hours and measured by high performance liquid chromatography. RESULTS: All three solutions that contained CAI efficiently diffused through the sclera with permeability constants that ranged from 2.8 to 5.5 x 10 cm/s. The scleral permeability constant derived for 2ME2 was 9.96 x 10 cm/s. The permeability constants obtained for both CAI and 2ME2 are similar to each other as well as to permeability constants measured for other small molecules such as fluorescein and dexamethasone fluorescein. CONCLUSION: Both CAI and 2ME2 traverse the sclera efficiently. These data combined with the reported inhibition of posterior segment neovascularization observed with these two molecules demonstrates that CAI and 2ME2 are good candidate molecules to treat posterior segment neovascularization by local delivery.

The application of statistical process control to horizontal strabismus surgery.

PURPOSE: Although originally developed to evaluate quality in manufacturing, statistical process control (SPC) techniques may be applicable to other frequently performed standardized processes. SPC analysis has rarely been used in medicine. We employed SPC charts to analyze the outcomes of one- and two-muscle horizontal strabismus surgery for esotropia and exotropia. METHODS: During a 33-month period between October 1, 1998 and July 1, 2001, we evaluated 95 patients undergoing strabismus surgery on either one or two previously unoperated eye muscles in one or both eyes. SPC charts were used to evaluate the success and validity of our surgical guidelines for horizontal recession and resection procedures. Data were divided into 2 groups, patients with esotropia and patients with exotropia, for computerized statistical analysis using QI Analyst (SPSS, Chicago, IL). RESULTS: Our results after horizontal strabismus surgery, both esotropia and exotropia repair, appear to follow the laws of statistical fluctuation or normal random variation. Our dose-response schedule produced a resultant ocular alignment or exit angle that appeared to be in statistical control, ie, variation from orthotropia that can be expected simply from normal random chance error with only a limited number of outliers. CONCLUSION: The resultant ocular alignment or exit angle after one- or two-muscle strabismus surgery may be described by standard models of statistical fluctuation. SPC may be a valuable method to analyze the variability of the results of many ophthalmologic procedures or treatments over time with the ultimate goal of producing better patient outcomes by decreasing variability.