Taiji Takanashi

Quantitative Analysis of Lens Changes After Vitrectomy by Fluorophotometry

We measured the amount of autofluorescence in the lens to evaluate quantitatively lens changes after vitrectomy. Thirteen phakic patients, ranging in age from 12 to 75 years, were studied after unilateral vitrectomy, with a follow-up period of more than two years (range, 26 to 55 months). Autofluorescence in the lens was measured at the center along the ocular axis by fluorophotometry. Lens autofluorescence in the eyes that underwent vitrectomy was significantly higher than in the contralateral eyes that were not operated on (P = .0003). The increase of autofluorescence was correlated significantly with the age at time of vitrectomy (P = .0008). There was no correlation between the increase in autofluorescence and the length of postoperative follow-up or the use of air during vitrectomy. Based on these results, we believe that oxidation of lens proteins intraoperatively may be one of the causes of development of nuclear cataract after vitrectomy.

Implantable biodegradable polymeric device in the treatment of experimental proliferative vitreoretinopathy

We investigated the use of a scleral plug of biodegradable polymer implanted at the pars plana to create a controlled drug-delivery system in the vitreous. We evaluated the efficacy of a plug containing doxorubicin hydrochloride to treat experimental proliferative vitreoretinopathy (PVR) in pigmented rabbits. An implantable device on the sclera, which imitates a scleral plug, containing 1% doxorubicin, was prepared with poly(lactic acid) (molecular weight, 20,000). The release of doxorubicin in phosphate-buffered saline was evaluated by spectro-photometry. After pars plana vitrectomy and plug implantation, concentrations of doxorubicin in the vitreous humor of the rabbits were measured by high performance liquid chromatography. The release profiles were evaluated during 5 weeks in vitro and 4 weeks in vivo. Cultured homologous fibroblasts were injected into the vitreous space to induce experimental PVR after gas compression of the vitreous. The scleral plugs were implanted at the pars plana in treatment animals (n = 11). Control rabbits (n = 11) were followed up without implantation after PVR induction. All eyes of the control group developed tractional retinal detachment at day 28, while the incidence of retinal detachment was decreased to 64% in the treated eyes. (P = 0.002). The implantation of the scleral plug effectively inhibited intravitreous proliferation of fibroblasts. This study demonstrated that the scleral plug of biodegradable polymers may have potential as a treatment modality for PVR.

Long-Term Prognosis of Extracapsular Cataract Extraction and Intraocular Lens Implantation in Diabetic Patients

Although cataract extraction with intraocular lens implantation (IOL) is being used for increasing numbers of patients, there is still insufficient information regarding the long-term outcome for these patients. In this retrospective study of 140 eyes of 102 patients, 97 eyes (69%) achieved a best visual acuity of 20/40 or better. After a minimum 6-month postoperative period, 26 eyes (19%) had developed retinopathy: eight eyes progressed from nonproliferative to proliferative retinopathy. Glycosylated hemoglobin levels and fasting blood glucose were significantly higher at time of surgery in the eight that progressed than in those who did not (P = 0.002, P = 0.034). There were 65 unilateral IOL implantations; in 10 (15%) of these eyes, retinopathy progressed. Retinopathy also progressed in 70% of the fellow eyes of these patients. In patients whose retinopathy did not progress, 95% of the fellow eyes also showed no progression. Also, patients with progression in the pseudophakic eye frequently had progression in the fellow unoperated eye. Postoperative progression was symmetrical (P = 0.0001). Our analysis suggests that progression of diabetic retinopathy following IOL implantation can be correlated to diabetic control at the time of surgery.

Scleral indentation optimizes visualization of anterior chamber angle during goniosynechialysis.

Purpose:To propose a new surgical technique for optimized visualization of the chamber angle using scleral indentation under an operating microscope in goniosynechialysis (GSL). Patients and Methods:Six volunteers with normal chamber angle and five patients with synechial angle closure glaucoma were examined. Scleral indentation 2 mm posterior to the limbus was performed during observation of chamber angle. Width of trabecular meshwork in images was recorded through a CCD camera mounted on an operating microscope. Trabecular-iris angle and trabecular-corneal angle obtained by ultrasound biomicroscopy were used for the parameters for the angle configuration. GSL with scleral indentation was performed in the patients. Results:According to the visibility of the chamber angle, width of trabecular meshwork in images significantly increased from 0.34 ± 0.08 mm equivalent (mean ± SD) to 0.67 ± 0.14 mm equivalent (P = 0.0001) with scleral indentation. According to the angle configurations, trabecular-iris angle significantly increased from 39.6 ± 3.8 degrees to 47.5 ± 6.6 degrees (P = 0.0016), and trabecular-corneal angle significantly decreased from 169.8 ± 5.5 degrees to 158.7 ± 5.4 degrees (P < 0.0001). All patients were successfully treated with GSL using scleral indentation. Conclusion:Scleral indentation provided the surgeon an optimized visualization of the anterior chamber angle. Deepening of the chamber angle and steeping in trabecular-corneal curvature probably induced the plane of the trabecular meshwork less oblique to the surgeons visual axis. This enhanced visualization promises the accuracy and safety of GSL.

Proliferative vitreoretinopathy shows predilection for the inferior fundus

We reviewed 112 consecutive cases of retinal detachment associated with grade C-1 proliferative vitreoretinopathy (PVR) to assess the initial location of the full-thickness retinal folds. A total of 47 eyes had PVR preoperatively, and 65 eyes demonstrated PVR postoperatively. Of the eyes affected preoperatively, 29 (56%) developed PVR in the inferior retina, as did 58 (74%) of the eyes affected postoperatively for a total of 87 eyes (67%). Eyes treated with cryoretinopexy had a higher incidence of PVR in the inferior retina (87.5%) than did those undergoing diathermy (57.6%) or photocoagulation (80%). Our findings suggested that the location of PVR may be influenced clinically by gravity. This tendency was more apparent after surgery, especially after cryoretinopexy, than preoperatively.