Estimación biométrica del volumen de humor acuoso en ojos con aceite de silicona en medios opacos / Biometric estimation aqueous volume in eyes with silicone oil in opaque media

Propósito: Estimar el volumen de humor acuoso como índice de viabilidad ocular. Métodos: El método de cálculo integral de sólidos en revolución por discos, es el utilizado para calcular el volumen del humor acuoso con forma de menisco depositado debajo del aceite de silicona gracias al efecto de la gravedad, y basando dichos cálculos en la mediciones biométricas de diferentes cortes ecográficos, que abarquen tanto el aceite de silicona como el humor acuoso, mediante ecografía ocular. Resultados: De tres modelos matemáticos realizados para el cálculo del volumen del menisco, uno de ellos es el que más se acerca a los valores empíricos, mostrando menor volatilidad en los resultados.

Purpose: To estimate the volume of aqueous humor as an ocular viability index. Methods: The integral calculus of solids in revolution by disks is the method used to calculate the volume of aqueous shaped meniscus deposited under the silicone oil through the effect of gravity, and basing such calculations on biometric measurements of different ultrasound sections, covering both silicone oil as the aqueous humor, by using ocular ultrasound. Results: From the three mathematical models made for calculating the volume of the meniscus, one of them is the closest to the empirical values, showing less volatility in results.

Active silicone oil removal with a modified vacuum syringe.

PURPOSE: At present, the number of clinical indications for the use of silicone oil (SO) has increased in intraocular surgery because of the advent of new techniques in vitreoretinal surgery, availability of better quality oils, and greater experience in its use. Consequently, the number of procedures for SO removal has increased, and support technologies for these procedures are always a concern. METHODS: A simple active technique for SO removal based on a 5-mL standard syringe with an 18G cannula was developed. The oil is suctioned into the syringe by the pulling effect of a spring assembled along the axis of the piston. No abrupt change in the intraocular pressure is produced because of the oil viscosity and the reduced diameter of the cannula. RESULTS: A technique for SO removal that has been used successfully during the past 7 years is presented in this article. During the 7-year period, 234 SO removals were performed without any complication or device failure. Using the present method, the average time for SO removal was 4 minutes. CONCLUSION: The average extraction time with the technique is 4 minutes, which is in the range of other active techniques, and it is faster than passive methods that are performed between 8 and 9 minutes. The technique is in line with the advantages of more elaborated active methods without using complex technology. It is considered to be highly successful and easy to implement.

Mixed vascular occlusion in a patient with interferon-associated retinopathy.

Interferon (INF)-associated retinopathy occurs in 15-64% of INF-treated patients, transforming this complication into a significant risk for visual impairment. This retinopathy has been described as an ocular complication with a variable clinical course, usually benign and asymptomatic. The most common findings are hemorrhages and cotton wool spots. Atypical ocular side effects include branch or central retinal artery occlusion, central retinal vein occlusion, anterior ischemic optic neuropathy, optic disc edema, neovascular glaucoma and vitreous hemorrhage. Some case series suggest that in most cases the clinical course of the disease is benign, asymptomatic and without long-term consequences and therefore do not recommend any specific treatment; they only recommend the discontinuation of INF in patients with severe manifestations or risk factors such as hypertension or diabetes mellitus. The case reported here presents an atypical manifestation of INF-associated retinopathy consisting of a mixed retinal vascular occlusion (arterial and venous), associated with severe occlusive inflammatory microangiopathy with extensive retinal damage by ischemia and a torpid clinical course despite suspension of treatment. These varieties of occlusive vascular events have not yet been found simultaneously in the literature and neither with an unfavorable clinical course. Although the clinical course of INF-associated retinopathy in most cases is asymptomatic, there may be complications with risk to vision, which is less common. The magnitude and severity of the consequences associated with INF therapy are to be determined in prospective further studies.

Vitreoretinal surgery of the posterior segment for explosive trauma in terrorist warfare.

BACKGROUND: To describe surgical management and establish anatomic and visual results of patients with explosive ocular trauma in terrorist attacks treated with extreme vitreoretinal surgery. METHODS: Retrospective study of clinical records (6-month follow-up) of patients with visual acuity (VA) of light perception or better with posterior segment injuries [vitreous hemorrhage, retinal detachment (RD), intra-ocular foreign bodies (IOFB), perforating trauma (PT)] from explosive weapons who underwent vitreoretinal surgery. We reviewed the demographic characteristics, type of weapon, time between injury and surgery, VA at arrival and 6 months after surgery, and type of trauma according to the International Trauma Classification. RESULTS: Fifty-seven out of 236 patients with ocular injuries from explosive weapons were included in the study; all of them were military men, average age 22 years (range 16-53 years). The average time between the blast and primary closing was 1 day, and 10 days between primary closing and vitreoretinal surgery. Open traumas by laceration accounted for 96% of cases and 4% were closed traumas; 76% of the eyes had IOFB, of which 18% involved PT; 5% had endophthalmitis. Contusion was the diagnosis for 100% of the closed traumas. Of the open traumas, 40% were localized at zone I, 44% at zone II, and 16% at zone III. Upon arrival, 98% of patients had VA 20/800-LP and 2% had >20/40. The patients with closed trauma had the injuries at zone III and presented VA 20/800-LP. All patients underwent posterior vitrectomy, scleral buckling, endotaponade and when required, lensectomy (82%), IOFB removal (72%), and/or retinectomy (25%). Postoperative VA improved in 43% of the patients, stabilized in 41% and evolved to NLP in 15% of the cases. Initial expressions of ocular trauma such as RD, PT and endophthalmitis suggest bad prognosis. CONCLUSIONS: We presented a series of patients with severe ocular trauma of the posterior segment from explosive weapons. These patients were treated according to our surgical protocol with extreme vitreoretinal surgery within the first 2 weeks after the blast; with our procedure we obtained stabilization or improvement of the VA for 84% of the cases.