盛岡市みたけの眼科　むらた眼科クリニック

Tube insertion has a long history of medical use, including ophthalmology. The intrachoroidal tube placement by using retro-ocular insertion through scleral approach would be useful to decrease tissue damages and increase the DEX level in posterior eye segment, especially disc-macula area locally. In addition, the intrachoroidal tube near the disc might be possible to maintain drug level by repeating drug injections through the tube.

This time, we have invented a simple procedure of a tube insertion through sclera for the intrachoroidal DEX delivery in posterior eye segment. This procedure would be helpful to increase DEX level in disc-macula area, and to maintain effective retino-choroidal DEX level by repeating the DEX injections. Therefore, in this study, we assessed whether this procedure was useful to maintain the DEX level in the posterior eye segment near the disc.
 

Purpose. To investigate the feasibility of laser-induced intrachoroidal dexamethasone (DEX) delivery as a potentially useful therapy for adjusting the most effective drug level to posterior segment eye diseases.

Methods. The implant was prepared by dissolving poly(DL-lactide) and DEX. In vitro release of DEX was evaluated at 7, 14, and 28 days by ELISA. In vivo, the DEX implant was inserted into the rabbit choroid, and then 10, 50, or 200 burns of photocoagulation were applied at the implant lesion, respectively. After treatment, the vitreous humor was immediately aspirated and the DEX level was measured by LC/MS/MS. Furthermore, the vitreous DEX level was measured at 1, 7, 14, and 28 days after the implantation and 50 burns of photocoagulation. The toxicity of laser-induced DEX implant was evaluated by ophthalmoscopy and light microscopy.

Endotoxin-induced uveitis (EIU) was induced after the DEX implantation and photocoagulation, and the anti-inflammatory activities were evaluated by grading clinical signs, protein concentrations, and histopathologic studies, respectively.
 

Purpose: To understand the possible roles of intra-choroidal implantation, we investigated the in vivo release of betamethasone phosphate (BP) from the intra-choroidal implant. Furthermore, we sought to evaluate the effect of intra-choroidal implantation of basic fibroblast growth factor (bFGF)–impregnated gelatin in promoting choroidal neovascularization (CNV).

Methods: 1) The intra-choroidal implant was made of poly(DL-lactide) containing 50% BP(0.15mg). The implant prepared as above was inserted into a choroidal pocket in the rabbit’s eye. The concentration of BP in the choroid sample at 4 weeks after implantation was determined by high-performance liquid chromatography (HPLC).

2) The intra-choroidal implant was made of gelatin impregnated 1μg of bFGF. The implant was placed into a choroidal pocket in the rabbit’s eye. The treated eye was examined by fluorescein angiography and light microscopy at weeks 2.
 

Murata Eye Clinic
5-8-30 Mitake, Morioka city, JAPAN 020-0122
murata-ganka@cap.ocn.ne.jp