[Experimental study on usefulness of silicone-fluorsilicone copolymer oil (SiFO) in vitreoretinal surgery]. / Estudio experimental sobre la utilidad del aceite de copolímero de silicona-fluorsilicona (SiFO) en la cirugía vitreorretiniana.

PURPOSE: To evaluate the usefulness of silicone-fluorsilicone copolymer oil (SiFO) as an intraoperative tool and a vitreous substitute in vitreoretinal surgery. METHODS: Handling properties of SiFO were tested and compared with those of perfluorooctane (PFO). The transparency of both substances was measured by spectrophotometry and subjectively assessed. Their tendency to dispersion was observed during injection in balanced saline solution (BSS) and after mechanized and manual shaking. Ease of injection and aspiration through small-gauge instruments was evaluated. Ocular tolerance to SiFO and PFO was studied after intravitreal injection in rabbit eyes: intraocular pressure, anterior segment inflammatory response and dispersion were evaluated, and a histopathological study was performed. RESULTS: Injection and aspiration of SiFO were more difficult than those of PFO because of its higher viscosity. PFO dispersed progressively into small droplets as early as two days after intravitreal injection, whereas SiFO remained as a single bubble for 14 days. Histopathologically both substances induced an inflammatory response over the inferior retina, with microvacuolated macrophages and foreign body giant cells, which were larger in eyes wearing SiFO. CONCLUSIONS: SiFO may be useful as an intraoperative tool, although its main drawback is a more difficult injection and aspiration compared to PFO. It has been well tolerated as a short-term vitreous substitute, but further clinical studies are needed.

[Corneal epithelial complications after vitrectomy: a retrospective study]. / Complicaciones corneales epiteliales de las vitrectomías: estudio retrospectivo.

PURPOSE: To establish the incidence, evolution and final visual outcome of corneal epithelial complications after vitrectomy in a consecutive series performed throughout a period of one year. METHODS: 195 consecutive medical records of patients vitrectomized in 2001 have been retrospectively reviewed. Patients were clinically evaluated the day after vitrectomy, during the first week, and then weekly for 3 months (minimum follow-up). Functional results have been established at the end of this period. RESULTS: 12 out of 195 eyes developed corneal epithelial complications after surgery (6.1%). Eight cases were diagnosed of persistent epithelial defect (4.1%), and four cases (2%) of necrotizing herpetic keratitis. Six out of 12 were diabetic. Corneal epithelial complications affected 10.5% of diabetic and 4.3% of non-diabetic patients (p=0.10). The majority of persistent epithelial defects healed without sequelae in less than two months. Herpetic keratitis required between 3 to 4 months to heal and caused corneal scarring in all cases. CONCLUSIONS: Persistent corneal epithelial defects after vitrectomy are a relatively frequent complication, mainly in diabetic patients. Recurrence of herpetic keratitis must also be kept in mind. This finding has not been previously reported and needs further studies.

[Iatrogenic retinal breaks during vitrectomy: retrospective study]. / Roturas retinianas iatrogénicas en las vitrectomías: estudio retrospectivo.

PURPOSE: To establish the incidence and characteristics of iatrogenic retinal breaks occurring during vitrectomy and to propose a protocol for their management. METHODS: Retrospective study of 195 consecutive vitrectomies performed in 2001. Minimum follow up was 3 months for all cases. RESULTS: 13 patients with iatrogenic retinal breaks (6.6%) have been detected. In 8 cases the breaks affected the peripheral retina, in 4 cases they were located in the posterior pole and there was one retinal dialysis. In 4 cases there were more than one retinal break. 9 patients (70%) were vitrectomized for diabetic retinal complications. In 12 cases, the breaks were detected during surgery and treated with endolaser and/or cryoretinopexy (3 cases located inferiorly). Nevertheless 7 cases (54%) developed a retinal detachment, 2 of which could be reattached. CONCLUSIONS: Among iatrogenic retinal breaks produced during vitrectomy, the peripheral ones are slightly more frequent than the breaks in the posterior pole. Iatrogenic breaks occur more frequently in diabetic patients, having a bad prognosis and often developing a retinal detachment despite endolaser or cryoretinopexy.