[Active drainage combined with air-fluid exchange for silicone oil removal: advantages and long-term follow-up]. / Ablation active d'huile de silicone par échange fluide-air: avantages et suivi au long cours.

INTRODUCTION: A number of silicone oil removal procedures are in use today. The purpose of this study was to evaluate the advantages of active drainage with air-fluid exchange for silicone oil removal. PATIENTS AND METHODS: We conducted a prospective study on patients operated on for retinal detachment with vitrectomy with silicone oil intraocular tamponade between January 2005 and January 2006. The surgical procedures were three-port vitrectomy with silicone tamponade. Silicone oil was removed with active drainage and air-fluid exchanges. Visual acuity, floaters, intraocular pressure, emulsion, and silicone oil complications were evaluated at 3, 6, 12, and 18 months. RESULTS: Fifty patients (50 eyes) underwent vitrectomy with silicone oil intraocular tamponade for RD with proliferative vitreoretinopathy. The mean duration of intraocular silicone oil tamponade was 4.5 months (1-15 months). Seventeen patients had complementary procedures such as phacoemulsification, epimacular membrane peeling, complementary retinopexy or intravitreal triamcinolone. At 1 year, the mean visual acuity was 3.2/10. One patient reported floaters. One patient had recurrent retinal detachment, one patient had intraocular hypertony, and significant emulsion was found in one patient. Microscopic emulsion was found in 20 patients. DISCUSSION: This surgical technique is longer and more invasive than simple passive ablation. However, complementary procedures could decrease the risk of recurrent retinal detachment and provide better visual rehabilitation. Better silicone oil removal seems to limit residual emulsion. CONCLUSION: Active drainage with air-fluid exchange for silicone oil removal is an interesting procedure. It could reduce short- and medium-term silicone oil complications in vitreoretinal surgery and increase the final visual outcome. However, a prospective comparative and randomized study is necessary to confirm our results.

[Circulatory consequences of retinal vein occlusions. Advantages of dynamic angiography]. / Conséquences circulatoires des occlusions veineuses rétiniennes.

PURPOSE: To compare angiographic features in patients with branch vein (BRVO) and central retinal vein occlusion (CRVO) and to discuss their possible significance. PATIENTS AND METHODS: Clinical and indocyanine green (ICG) videoangiographic data of 35 patients with CRVO and 5 patients with BRVO were reviewed. In order to more fully understand the significance of hemodynamic alterations, patients with a decrease in retinal flow velocity from other causes (optic neuritis, carotid-cavernous fistula, carotid artery stenosis) were compared to patients with vein occlusion. RESULTS: Whatever the type of occlusion, the most frequent abnormality was the presence of pulsatile venular outflow, which at the acute phase was present in the majority of cases. The decrease in arterial velocity was visualized by the presence of diastolic reversed flow. There was no correlation between visual prognosis and hemodynamic alterations. Apart from vein occlusion, the pulsatile venular outflow was present in situations where increased venous pressure was present. CONCLUSIONS: BRVO and CRVO have similar alterations of venous flow. Videoangiography can electively show pulsatile venular outflow and reverse diastolic arterial flow, and thus contributes additional information to conventional angiography. Pulsatile venular outflow is probably due to a combination of elevated venous pressure and decreased plasma velocity. Videoangiography provides new insight to the consequences of retinal vein occlusion and will possibly lead to a better understanding of the sequence of events that lead to visual loss.

Analysis of retinal and choroidal circulation during central retinal vein occlusion using indocyanine green videoangiography.

OBJECTIVE: To explore the hemodynamic changes and their correlation with clinical presentation during central retinal vein occlusion. MATERIALS AND METHODS: Retrospective, 2-center study. The medical records of 27 patients with central retinal vein occlusion were reviewed. For each patient, the plasma transit in central retinal vessels and in peripapillary choroidal vessels was analyzed using indocyanine green videoangiography. RESULTS: The incidence of alteration in retinal plasma transit, ie, pulsatile filling of arteries and/or veins and increased arteriovenous filling time, was inversely correlated to duration from the onset but not to funduscopic features. Among the 14 patients with less than 1 month's duration of symptoms, 3 developed chronic macular edema, and impairment of arterial flow preceded its onset. Among the 10 patients with opticociliary circulation, choroidal drainage routes were identified in 5 cases, with pulsatile filling in 3. CONCLUSIONS: Early in the course of central retinal vein occlusion, arterial and/or venous flow alterations are present, irrespective of visual acuity, vein dilation, or fundus hemorrhages. These alterations are less frequent in chronic than in recent-onset central retinal vein occlusion. The mechanisms of these alterations remain uncertain but may involve arterial constriction and/or intermittent venous compression. The relationship between these alterations in retinal flow and the secondary onset of macular edema or capillary nonperfusion deserves further investigation.

Linear dichroism of the retinal nerve fiber layer expressed with Mueller matrices.

An electro-optic device is used that permits the measurement of polarized absorption spectra (linear dichroism). The change of the polarization state of a light beam brought about by passage through the optic elements of a dichrograph are described mathematically by a transformation of the Stokes vector. The polarization or absorption properties of the optical elements are described by the Mueller matrices. The dichroic properties of sheep retina and cornea are studied in vitro.