Among various methods to treat retinal diseases, intrascleral drug delivery is the most efficient method because of its easy application and high efficiency. However, the sclera which is the formidable barrier tissue of the eyes hinders high molecular weight(MW) compounds from permeation through sclera. In this study, we developed microneedle-pen(MNP) for impact insertion into the sclera. It was expected that the MNP would partially penetrate the sclera for deep drug delivery in the vertical direction. To confirm that the high MW compound can permeate through and diffuse along the scleral layer, fluorescein isothiocyanate labeled dextran(FITC-dextran) with various MW(4,000, 70,000 and 150,000 kDa) was selected as a model drug. The mixture of DI water, CMC and model drugs(25:5:1) was coated on the surface of microneedle which was fabricated tip of the MNP. The impact insertion was performed on porcine scleral samples and then optimal cutting temperature(OCT) blocks were prepared immediately and after 3 and 6 hours of insertion. The distribution of fluorescent signals was measured by fluorescent microscopy(N=4). Fluorescent distribution was defined horizontal/vertical distance from wound mark of scleral samples. As the results, when drug permeation time was increased from 0 to 6 hours, the fluorescent distribution was increased horizontal direction(95.8%) and vertical direction(61.2%). In addition, the fluorescent distributions after 6 hours of microneedle insertion were decreased as MW were increased.