Comparisons of retinal nerve fiber layer thickness changes after macular hole surgery / Comparação nas alterações da espessura da camada de fibras nervosas retinianas após cirurgia de buraco macular

ABSTRACT Purpose: To compare postoperative changes in retinal nerve fiber layer thickness in patients with macular holes treated with vitrectomy with Brilliant Blue-assisted internal limiting membrane peeling. Methods: Twenty-two eyes of 20 patients with macular holes were studied. Each eye was selected to undergo Brilliant Blue-assisted internal limiting membrane peeling. The circumferential retinal nerve fiber layer thickness was determined using spectral domain optical coherence tomography preoperatively and 2 months postoperatively. Mean overall and sectoral retinal nerve fiber layer thicknesses were obtained for each patient. Results: There was no statistically significant difference (p≥0.05) between the pre- and post-treatment measurements in relation to each CFN variable, i.e., on average, pre-treatment measures were the same as post-treatment measures. Furthermore, despite the differences between the pre- and post-treatment measures always being positive (pre-post >0), they are not statistically significant. Conclusions: This study showed no significant decrease in retinal nerve fiber layer thickness measurements after macular holes surgery, regardless of age or sex.

RESUMO Objetivo: Comparar as alterações pós-operatórias na espessura da camada de fibras nervosas da retina em pacientes com buracos maculares submetidos à vitrectomia via pars-plana associada à remoção de membrana limitante interna. Métodos: Foram estudados 22 olhos de 20 pacientes consecutivos diagnosticados com buraco macular. Todos os pacientes foram submetidos à vitrectomia via pars-plana e remoção de membrana limitante interna corada com azul brilhante. A espessura da camada de fibras nervosas da retina em região peripapilar foi determinada por tomografia de coerência óptica de domínio espectral antes e 2 meses após a cirurgia. As espessuras totais e espessuras setoriais da camada de fibras nervosas da retina foram obtidas para cada paciente. Resultados: Os resultados mostram que não existe diferença estatisticamente significativa (p≥0,05) entre as medidas pré e pós-operatórias em relação a cada uma das variáveis. Conclusão: Este estudo não demonstrou diminuição significativa nas medidas da espessura da camada de fibras nervosas retinianas após a cirurgia de buraco macular, independente da faixa etária ou sexo.

Evolution of optic nerve and retina alterations in a child with indirect traumatic neuropathy as assessed by optical coherence tomography / Evolução das alterações no nervo óptico e na retina em criança com neuropatia traumática indireta avaliadas com tomografia de coerência óptica

ABSTRACT Herein, we describe the case of a 4-year-old child with indirect traumatic optic neuropathy and serial changes of the optic nerve head and retinal nerve fiber layer (RNFL) documented using optical coherence tomography (OCT). Visual acuity improved despite progressive RNFL thinning and optic disc pallor. We concluded that OCT may be useful for monitoring axonal loss but may not predict the final visual outcome.

RESUMO Descrição do caso de uma criança de 4 anos de idade com neuropatia óptica traumática indireta, cujas alterações no nervo óptico e na camada de fibras nervosas da retina foram documentadas com tomografia de coerência óptica seriadas. A acuidade visual apresentou melhora apesar da diminuição progressiva da camada de fibras nervosas e da palidez do disco óptico. Em conclusão, a tomografia de coerência óptica pode ser útil para monitorar a perda axonal na neuropatia óptica traumática indireta, sem no entanto, predizer o desfecho visual.

State of the art in chromovitrectomy / Estado da arte da cromovitrectomia

Vitrectomy is a surgery that involves complex and delicate techniques that treat diseases such as macular hole, epiretinal membrane and diabetic macular edema. Chromovitrectomy is one of these techniques and includes the use of coloring agents such as vital dyes or crystals to enhanced visibility of transparent structures during vitrectomy. The aim of this study was to present a modern approach, based on scientific evidence, about the application and indication of vital coloring agents during vitrectomy. The use of such agents has made this surgery more predictable and has increased its post-operative prognosis. Although research on chromovitrectomy is currently expanding there is still not an established gold standard dyeing agent.

A cirurgia vitreorretiniana é uma cirurgia que envolve técnicas complexas e delicadas que tratam doenças como buraco macular, membrana epirretiniana e o edema macular diabético. A cromovitrectomia é uma dessas técnicas que incluem o uso de corantes compostos de pigmentos vitais ou cristais para melhorar a visibilização de estruturas transparentes durante a cirurgia de vitrectomia. O objetivo desse artigo foi apresentar uma abordagem atual, baseada em evidências, sobre a aplicação e indicação de corantes vitais durante a cirurgia vitreorretiniana. O emprego desses corantes possibilitou uma maior previsibilidade para a cirurgia, melhorando assim seu prognóstico pós-operatório. Apesar do campo da cromovitrectomia está em plena expansão de pesquisas, um corante gold standard para cromovitrectomia ainda não está estabelecido.

Retinal detachment and gyrate atrophy of the choroid and retina: case report / Descolamento de retina e atrofia girata da coroide e retina: relato de caso

To report a case of gyrate atrophy of the choroid and retina associated with retinal detachment. Hyperornithinemia confirmed the diagnosis of gyrate atrophy. Pars plana vitrectomy with silicone oil infusion was performed with good anatomical results, despite the persistence of low visual acuity. Retinal detachment is a rare complication of gyrate atrophy and can be managed with pars plana vitrectomy and silicone oil. We discuss the possible mechanisms that led to low visual acuity.

Descrever um caso de atrofia girata da coroide e retina associado com descolamento de retina. Altos níves de ornitina sérica confirmaram o diagnóstico de atrofia girata. Vitrectomia via pars plana com infusão de óleo de silicone foi realizada, com bom resultado anatômico, apesar da baixa acuidade visual persistente. Descolamento de retina é uma rara complicação da atrofia girata e pode ser manejada com vitrectomia via pars plana e óleo de silicone. Discutiremos os possíveis mecanismos que levaram à baixa acuidade visual.

Padronização do eletrorretinograma de campo total em cães / Full field electrorretinogram standartization in dogs

Eletrorretinograma (ERG) é o meio diagnóstico objetivo e não-invasivo para avaliar a função retiniana e detectar precocemente, em várias espécies, lesões nas suas camadas mais externas. As indicações mais comuns para ERG em cães são: avaliação pré-cirúrgica de pacientes com catarata, caracterização de distúrbios que causam cegueira, além de servir como importante modelo para o estudo da distrofia retiniana que acomete o homem. Vários são os fatores que podem alterar o ERG tais como: eletrorretinógrafo, fonte de estimulação luminosa, tipo do eletrodo, tempo de adaptação ao escuro, tamanho pupilar, opacidade de meios e protocolo de sedação ou anestesia; além da espécie, raça e idade. Objetivou-se com este estudo padronizar o ERG para cães submetidos à sedação, seguindo o protocolo da International Society for Clinical Electrophysiology of Vision (ISCEV), utilizando Ganzfeld e eletrodos Burian Allen. Foram realizados 233 eletrorretinogramas em cães, 147 fêmeas e 86 machos, com idades entre um e 14 anos. Dos 233 cães examinados, 100 apresentavam catarata em diferentes estágios de maturação, 72 eram diabéticos e apresentavam catarata madura ou hipermadura, 26 apresentaram eletrorretinograma compatível com degeneração retiniana progressiva, três apresentaram eletrorretinograma compatível com síndrome da degeneração retiniana adquirida subitamente e 32 não apresentaram lesão retiniana capaz de atenuar as respostas do ERG, sendo considerados normais quanto à função retiniana. A sedação foi capaz de produzir boa imobilização do paciente sem rotacionar o bulbo ocular, permitindo adequada estimulação retiniana bilateralmente, com auxílio do Ganzfeld. O sistema eletrodiagnóstico Veris registrou com sucesso e simultaneamente de ambos os olhos, as cinco respostas preconizadas pela ISCEV. Como o ERG de campo total tornou-se exame fundamental na rotina oftalmológica, sua padronização é indispensável quando se objetiva comparar resultados de laboratórios distintos...

Electroretinogram (ERG) is an objective non invasive diagnostic method to evaluate retinal function which permits the early detection of lesions at retinal external layers, even before the appearance of clinical signs. In dogs, ERG is mostly utilized for preoperative evaluation in patients presenting cataracts; characterization of disturbances causing blindness, among the utilization of dogs as animal models in scientific research. Several factors interfere in ERG responses, such as the ERG machine, light stimulation, electrode, time spent on dark adaptation, pupil size, means opacity, sedation or anesthetization, species, breed and age. The purpose of this study was to standardize the full field ERG in sedated dogs, according to the International Society for Clinical Electrophysiology of Vision (ISCEV) protocol, using Ganzfeld and bipolar electrodes. Two hundred thirty threes ERGs were performed in 147 female and 86 male with ages from 1 to 14 years old. Among those 233 dogs, 100 presented cataracts in different stages of maturation, 72 were diabetic and presented mature or hypermature cataracts, 26 presented ERG compatible to progressive retinal degeneration, 3 presented ERG compatible to sudden acquired retinal degeneration syndrome; for 32 dogs no abnormal ERG was registered and they were considered as having normal retinal function. Sedation was capable to induce a good immobilization with no bulb rotation, resulting uniform retinal stimulation, using Ganzfeld. Veris system successfully registered all 5 ISCEV responses, simultaneously from both eyes, at the same time. Full field ERG became a fundamental ophthalmic exam, then, its standardization is mandatory to allow comparison between ERGs from different laboratories. The reliability and reproducibility of this protocol has shown very good responses, using ISCEV protocol, Veris system, Ganzfeld and Burian Allen electrodes in sedated dogs.

Características del trauma ocular asociadas con la necesidad de cirugía retiniana de urgencia / Ocular trauma characteristics associated with urgent retinal surgery

Objetivo: Identificar las características del sistema de clasificación de lesiones mecánicas oculares más frecuentes en ojos que requieren cirugía retiniana de urgencia y evaluar su valor predictivo, para determinar su utilidad en el pronóstico temprano. Material y métodos: Se evaluaron retrospectivamente pacientes atendidos entre 1998 y 2007 y se asignaron a uno de dos grupos: 1 (con lesiones que requerían cirugía retiniana de urgencia) y 2 (sin ellas). Se determinó la proporción e intervalos de confianza (IC) de 95 % que representaba el grupo 1; se identificaron las características más frecuentes en el grupo 1 y su proporción se comparó con la del grupo 2 mediante χ2 y razón de momios. Se determinaron los valores predictivos de cada característica para identificar al grupo 1. Resultados: 238 ojos, edad promedio de los pacientes de 27.5 años; 10 ojos se asignaron al grupo 1 (4.2 %, IC 95 % = 1.65-6.75) y 228 al 2. Las características más frecuentes del grupo 1 fueron globo abierto (90 %), tipo A abierto (50 %), tipo C abierto (30 %), grado 4 (70 %) y zona III (70 %). El valor predictivo positivo fue de 60 % para trauma abierto tipo C, y menor a 50 % en el resto de las características. Conclusiones: Aunque existieron características asociadas significativamente con la necesidad de cirugía retiniana de urgencia, su valor predictivo fue insuficiente por la baja proporción de ojos que requería esta intervención, por lo que se sugiere utilizar como parámetro de referencia al globo abierto o la pérdida visual, independientemente de las lesiones existentes.

BACKGROUND: The most common features of the system for classifying ocular injuries of the eye in patients who require urgent retinal surgery were identified, and their predictive value was estimated in order to determine whether they are useful in detecting these patients. METHODS: Patients with ocular trauma between 1998 and 2007 were retrospectively evaluated and assigned to one of two groups: group 1 (with injuries that required urgent retinal surgery) and group 2 (without those injuries). The rate and 95% confidence intervals (CI) that group 1 accounted for were identified. The rate of the most common features in group 1 was identified and compared with their rate in group 2 using chi(2) and odds ratio. Predictive values of those features for detecting group 1 were calculated. RESULTS: Two hundred thirty eight eyes (mean age: 27.5 years) were included. Ten eyes were assigned to group 1 (4.2%, 95% CI 1.6-6.7) and 228 eyes were assigned to group 2. The most frequent features in group 1 were open globe (90%), type A open globe (50%), type C open globe (30%), grade 4 (70%) and zone III (70%). The positive predictive value was 60% for type C open globe, and <50% for the remaining features. CONCLUSIONS: Although some clinical features had a statistical and clinical association with the need for urgent retinal surgery, their predictive value was insufficient because the rate of eyes that required this intervention was low. The results suggest that open globe and visual loss should be used as referral criteria, regardless of the injuries found.

Comparison of classic peribulbar anesthesia and new entry point [single percutaneous injection technique] in vitroretinal surgery

To describe the method that seeks to improve the administration of regional anesthesia for vitroretinal surgery avoiding the risk of potential complications associated with other techniques through comparison of safety and efficacy of classic peribulbar anesthesia versus single percutaneous technique using a prospective, randomized clinical trial. One hundred patients were randomized to classic peribulbar and single percutaneous peribulbar technique after informed consent. Pain during administration of anesthesia, during surgery was graded on a visual analogue pain scale and compared for both techniques. Globe akinesia, analgesia and IOP measurements before and after administration of anesthesia, detection of distribution of local anesthetic agent by ultrasound scanning and complications related were also compared. Twenty out of 50 [40%] patients of group 1[classic pirebulbar] and 36/50 [72%] of group II [single percutaneous technique] experience no pain during administration of anesthesia. Scores for globe akinesia and anesthesia were less satisfactory in group 1 and supplemental blocks required in 8% of the patients while in group II all of the patients [100%] showed proper globe akinesia and anesthesia. There were significant elevation in mean IOP following injection in both groups and the incidence of subconjunctival haemorrhage, chemosis and echymosis were more frequent in group 1. Single percutaneous peribulbar technique proved to be a safe and efficient technique that offers excellent anesthesia and akinesia with less complication for various ophthalmic procedures

Transpalpebral extrusion of solid silicone buckle

Explants used in retinal reattachment surgery occasionally extrude. Cheese-wiring of the suture through the sclera consequent to raised intraocular pressure allows the buckle to loosen and/or unfold. Subsequent infection, often with Staphylococcus albus, accelerates the process of extrusion. Commonly, such explants are of silicone sponge. The reported case is unusual in that the extrusion occurred through the upper lid, and involved a solid silicone explant

Peribulbar block in pediatric posterior segment ocular surgery

Vitreous and retinal [VR] surgery with or without scleral buckling is associated with significant postoperative pain in adults, and recent studies have addressed the effect of retro or peribulbar block on these parameters VR surgery in children has received little attention regarding the incidence of pain and the role of regional anesthesia in modifying these parameters. In this study, we compared peribulbar block with conventional opioid analgesia in children undergoing VR surgery. In a prospective, randomized, single-blind study, 85 children [age 8 to 14 years] were allocated to receive peribulbar block [n = 42] or intravenous fentanyl 2micro g/kg [n = 43] after induction of general anesthesia. Parameters compared were: Intraoperative incidence of oculocardiac reflex and requirement for additional analgesic; postoperative pain intensity; time to first analgesic, total number of postoperative analgesic supplements; and parental assessment of the child's postoperative comfort at 24 hours. The incidence of intraoperative oculocardiac reflex was significantly less in the peribulbar group [p = .0001]. Significantly more children receiving peribulbar block were pain free on awakening [p = .0004] and throughout the postoperative period. The number of children requiring opioid was significantly lower with peribulbar block [p = .008]. Peribulbar block appears to be a safe and clinically superior alternative to intravenous fentanyl for pediatric VR surgery

Estudo experimental da aplicação retiniana do laser infravermelho via transescleral sob condições de baixa visibilidade / Transscleral infrared laser retinal photocoagulation experimental study under low visibility conditions

OBJETIVOS: Pesquisa experimental, com laser de diodo infravermelho, para estimar a segurança, a reprodutibilidade e a permeabilidade da parede ocular à sua atuação clínica, quando aplicado via transescleral, em condições de baixa visibilidade. MÉTODOS: Submetemos olhos de coelhos pigmentados da raça Nova Zelândia à fotocoagulação retiniana por laser de diodo infravermelho. No olho direito, realizamos fotocoagulação via transescleral sob parâmetros de potência e tempo pré-determinados clinicamente. No olho esquerdo, foram repetidos os mesmos valores da potência e tempo usados no olho direito, desta vez, via transpupilar. Imediatamente e após 2 meses, estudos clínicos baseados na retinografia e histopatológicos foram realizados. RESULTADOS: A permeabilidade da parede ocular, quando da aplicação do laser de diodo infravermelho via transescleral, variou entre 58,95 e 63,87 por cento. A média da permeabilidade da parede ocular a 300 mW (63,14 por cento) mostrou-se significativamente superior àquela da permeabilidade da parede ocular encontrada a 500 mW (59,11 por cento), (P<0,05). CONCLUSÕES: Este estudo sugere a existência da relação dose-resposta em relação aos parâmetros empregados na aplicação do laser de diodo infravermelho via transescleral, com permeabilidade da parede ocular mensurável e reprodutível. Nenhuma rotura, hemorragia ou descolamento da retina ou vítreo foi constatado aos exames subseqüentes às aplicações do laser de diodo infravermelho, o que torna o uso da fotocoagulação via transescleral, no modelo experimental, seguro, mesmo sob condições de baixa visibilidade dos meios.

PURPOSE: Retinal photocoagulation under poor visualization condition is often required. Transscleral infrared laser can be used as an alternative to regular transpupillary treatment. Based upon retinographic measurements, we proposed to estimate the reproducibility as well as ocular wall permeability rate for this treatment. Our primary goal was to evaluate whether this technique can deliver adequate photocoagulation at predetermined parameters without direct retinal visualization. METHODS: In New Zealand pigmented rabbits, optimal transscleral infrared diode laser settings were administered to the right eye. With the same parameters, transpupillary photocoagulation was repeated in the left eye. Retinographic and clinical examinations were performed immediately and two months later. RESULTS: Ocular wall permeability rate varied between 58.95 and 63.87 percent. Average permeability using a power of 300 mW (63.14 percent) was found to be higher than that encountered before its enhancement up to 500 mW (59.11 percent), (P<0.05). CONCLUSIONS: Setting parameters showed dose-response effect. No retinal hole or retinal detachment was noticed in any rabbit. Transscleral infrared photocoagulation appeared to be a reproducible and secure method in the experimental model.

Depósito subconjuntival de óleo de silicone após cirurgia vitreorretiniana / Subconjunctival deposit of silicone oil after vitreoretinal surgery

OBJETIVO: Comprovar a presença do óleo de silicone no espaço subconjuntival de pacientes submetidos previamente à cirurgia vitreorretiniana por meio de estudo histopatológico das amostras conjuntivais obtidas, nos quais o exame biomicroscópico não foi capaz de comprovar sua presença. Determinar qual a incidência da presença do óleo de silicone no espaço subconjuntival em uma série de casos e quais implicações clínico-patológicas. MÉTODOS: Estudo prospectivo em 30 olhos de 30 pacientes. Foram incluídos no estudo os pacientes que haviam sido submetidos previamente à cirurgia vitreorretiniana com implante intra-ocular de óleo de silicone e que possuíssem indicação para retirada do óleo de silicone e que não apresentassem ao exame biomicroscópico sinais da presença do óleo de silicone no espaço subconjuntival. Após sua retirada, a amostra era encaminhada para análise histopatológica pelo método de hematoxilina-eosina. RESULTADOS: Foi observada a presença de espaços vazios correspondentes às áreas de localização do óleo de silicone, removido durante processamento histológico, em 10 (33 por cento) amostras. Observou-se também a presença de sinais inflamatórios na substância própria caracterizada por congestão vascular, leucostase e infiltrado linfomononuclear em 27 (90 por cento) amostras. CONCLUSÃO: Portanto, em pacientes submetidos ao implante intra-ocular do óleo de silicone, devemos suspeitar que o óleo esteja presente no espaço subconjuntival, mesmo que o exame biomicroscópico pareça normal.

PURPOSE: To assess the histopathological findings of conjunctival specimens from patients submitted to vitreoretinal surgery with intraocular silicone oil injection. METHODOS: Prospective analyses of 30 eyes of 30 patients were evaluated. Before the patients underwent removal of the intraocular silicone oil, conjunctival excision was performed and submitted to histopathologic examination. RESULTS: The presence of empty spaces corresponding to silicone oil location was positive in 10 (33 percent) specimens. The presence of inflammatory cells, vascular congestion, leukostases, lymphocyte and monocyte infiltrates were positive in 27 (90 percent) specimens. The presence of silicone oil was positive in 10 (33 percent) specimens. Therefore, in those patients who undergo vitreoretinal surgery, silicone oil may be present in the conjunctiva or subconjunctival space, even if biomicroscopic examination seems to be normal. According to our knowledge, this is the first study with the purpose to assess the histopathological findings of conjunctival specimens from patients submitted to vitreoretinal surgery with intraocular silicone oil injection. CONCLUSION: Ophthalmologists should be aware of this possible complication after intraocular use of silicone oil after vitreoretinal surgery.

Estabilidade visual na retinopatia diabética tratada por panfotocoagulação com laser / Visual stability in diabetic retinopathy treated by panretinal laser photocoagulation

OBJETIVO: Avaliar o efeito da "laserterapia" na acuidade visual em portadores de retinopatia diabética avançada e sem queixas visuais. MÉTODOS: Desenvolveu-se estudo observacional descritivo em portadores de retinopatia diabética avançada e sem queixas visuais, submetidos a panfotocoagulação retiniana com laser de argônio. Foi realizado exame oftalmológico completo. Entre o 3° e o 5° meses do tratamento, foi repetido o exame inicial. Para comparação da acuidade visual, entre período pré e pós-tratamento, foi utilizado o teste não-paramétrico de Wilcoxon. RESULTADOS: A amostra foi constituída por 44 pacientes, totalizando 67 olhos, sendo que 37 (55,2 por cento) apresentavam retinopatia diabética proliferativa e 30 (44,8 por cento) não proliferativa grave ou muito grave. A acuidade visual pré-tratamento variou de 0,5 a 1,0 (média de 0,83 ± 0,17). Não houve alteração estatisticamente significante na acuidade visual (p= 0,057) pré e pós-tratamento no período estudado. CONCLUSÃO: Houve estabilidade visual pós-tratamento com a panfotocoagulação, o que enfatiza a necessidade de intervenções em fases mais precoces da retinopatia diabética para preservar a função visual.

PURPOSE: To evaluate the effect of laser treatment in the visual acuity caused by advanced diabetic retinopathy without visual complaints. METHODS: A descriptive observational study was developed in advanced diabetic retinopathy patients not presenting visual complaints. The patients were submitted to argon laser panretinal photocoagulation after ophthalmological examination as well as retinography and retinal angiofluoresceinography. The same initial exams were repeated between third and fifth months after the treatment. The non-parametric Wilcoxon test was employed for statistical evaluation between the visual acuities before and after the treatment. RESULTS: The sample involved 67 eyes of 44 patients. Of these 67 eyes, 37 (55.2 percent) presented proliferative diabetic retinopathy and 30 (44.8 percent) showed severe and severe non proliferative diabetic retinopathy. The visual acuity before the treatment ranged from 0.5 to 1.0 (mean 0.81 ± 0.16). There was no significant statistical difference between the visual acuity (p= 0.057) before and after the treatment during the follow-up period of five months. CONCLUSION: The visual stability after panretinal argon laser photocoagulation indicated the need of this treatment in early phases of diabetic retinopathy in order to preserve the visual function.

Estudo macular em olhos com óleo de silicone por meio da tomografia de coerência óptica / Optical coherence tomography macular study on eyes filled with silicone oil

OBJETIVO: Demonstrar a eficácia da tomografia de coerência óptica na avaliação da estrutura anatômica macular em olhos com a cavidade vítrea preenchida por óleo de silicone. MÉTODOS: Estudo observacional descritivo de 28 (vinte e oito) pacientes submetidos a vitrectomia com utilização de óleo de silicone como substituto vítreo. Estes pacientes foram avaliados pela biomicroscopia, oftalmoscopia indireta e pela tomografia de coerência óptica. RESULTADO: Todos os pacientes apresentaram retina aplicada no pós-operatório. A realização da tomografia de coerência óptica não apresentou dificuldade técnica na sua execução. O "cisto" de retina, membrana epi-retiniana e buraco lamelar foram apenas detectados na tomografia de coerência óptica. CONCLUSÃO: A tomografia de coerência óptica demonstrou boa eficácia para detectar alterações maculares em olhos com óleo de silicone. Assim, evidenciamos que é factível a execução deste exame e que este pode nos ajudar a diagnosticar alterações subclínicas no pós-operatório nestes pacientes.

PURPOSE: To demonstrate optical coherence tomography efficacy to evaluate macular anatomical outcomes, in eyes with silicone oil-filled vitreous cavity after vitrectomy. METHODS: A descriptive observational study of 28 (twenty-eight) patients submitted to pars plana vitrectomy having silicone oil as vitreous substitute. The macular findings were observed by means of indirect binocular ophthalmoscope, biomicroscopy and optical coherence tomography examinations. RESULTS: During the follow-up period the retina remained attached in all patients. In some cases, intraretinal cysts, epiretinal membrane and lamellar macular hole were observed only by optical coherence tomography examination. CONCLUSION: Optical coherence tomography provided improved imaging of finer retinal structures in eyes with silicone oil-filled vitreous cavity. Therefore, optical coherence tomography examination should be systematically performed in eyes filled with silicone oil to recognize changes in retinal morphology.

Comparative Evaluation of Radial Optic Neurotomy and Panretinal Photocoagulation in the Management of Central Retinal Vein Occlusion

PURPOSE: There is currently no treatment proven effective for central retinal vein occlusion (CRVO). Radial optic neurotomy (RON) has recently surfaced as a new treatment for the disorder, however, and we compare here the visual acuity (VA) and arteriovenous transit time (AVTT) following RON and panretinal photocoagulation (PRP). METHODS: We conducted a retrospective, uncontrolled study of 27 patients. Of 27 eyes diagnosed with CRVO, 16 were treated with panretinal photocoagulation (PRP) and 11 with RON. VA and fluorescein angiography were used to monitor the evolution of CRVO, and for follow-up. RESULTS: All patients underwent PRP or RON with no major complications. The difference between pre- and post-operative VA was not statistically significant for either group (p=0.092 on PRP; p=.0081 on RON). The change in AVTT was also not statistically significant for either group (p=0.024 on PRP; p=0.027 on RON). Ultimately, we found no statistically-significant difference in comparing VA and AVTT for the two groups (p=0.074 on VA; p=0.510 on AVTT). CONCLUSIONS: No evidence supporting the effectiveness of RON could be found in this study, suggesting that surgical decompression by RON may not be effective for treating CRVO. Further studies regarding the efficacy of RON should be made.

An experimental rabbit model of rhegmatogenous retinal detachment / 华中科技大学学报（医学）（英德文版）

An experimental model of rhegmatogenous retinal detachment (RRD) in rabbits was established to simulate the pathophysiologic condition of human RRD. 24 rabbits were randomly divided into 3 groups and underwent vitrectomy with a vitrector and/or retinotomy with a Charles flute needle, with 12 in group I (vitrectomy and retinotomy), 7 in group I (retinotomy) and 5 in group III (vitrectomy). All animals underwent follow-up examinations with direct and indirect ophthalmoscopy and fundus photography 12 h and day 1, 3, 5, 7, 10, 14, 21, and 28 after the procedure(s). Retinal changes were recorded. As a result, 10 RRDs were successfully established in group I. Direct and indirect ophthalmoscopy and fundus photography demonstrated typical features of RRD. No RRD developed in group II and III. It was concluded that the experimental rhegmatogenous retinal detachment produced in a rabbit model after vitrectomy with retinotomy in this study was a convenient and reliable one. This RRD model mimicked the typical pathophysiological changes in humans.

Evaluation of different anaesthetic techniques for insertion of laryngeal mask airway in cardiac patients undergoing urgent retinal surgery

Forty-five ASA I and II adult patients scheduled for urgent retinal surgery were included in the study after giving a written informed consent. Patients were randomly divided into three equal groups; 15 patients each: Group P [propofol group], group S [sevoflurane group] and group MT [midazoIam-thiopentone group]. Induction of anaesthesia was done by propofol in group P in a dose of 3 mg.kg[-1] while 8% sevoflurane in 50% nitrous oxide in oxygen was used for induction in group S. In-group MT, midazolam was given iv in a dose of 0.1 mg.kg[-1] followed after three minutes with thiopentone in a dose of 5 mg.kg[-1]. The laryngeal mask airway [LMA] was inserted using the standard method described by Brain. The three groups were comparable as regards age, weight, gender and type of surgical procedures. There were significant decrease in heart rate, MABP, and CI compared with baseline values in group P and group MT [P<0.05]. There was insignificant difference between the three groups as regards percentage of patients with excellent to satisfactory quality of LMA insertion being 90%, 85%, and 95% in group P, S, and MT respectively. Time of insertion of LMA was significantly shorter in propofol group compared with the other two groups [P<0.001]. The number of attempts of insertion of LMA was significantly higher in sevoflurane group. The percentage of patients who received additional propofol doses was significantly less in sevoflurane group compared with other two groups [P<0.05]. During trial of insertion of LMA, it was successfully inserted in high percentage of patients in the first minute in both propofol and midazolam-thiopentone groups compared with sevoflurane group [P<0.001]. The incidences of cough, laryngeal spasm and inadequate jaw relaxation were higher while the duration of apnoea was significantly shorter in sevoflurane group compared with the other two groups [P<0.001]. There was insignificant difference between the three groups as regards the incidences of hiccough, head movement, and bronchospasm. It could be concluded that the use of sevoflurane-N[2]O for insertion of LMA in cardiac patients was associated with greater degree of haemodynamic stability. The ease and quality of insertion of LMA was comparable between the three groups. The time for insertion of LMA using sevoflurane -N[2]O was longer but the incidence of respiratory depression was less compared with the other two groups

comparative study between pre-emptive peribulbar block and intravenous fentanyl in pediatric vitreoretinal surgery

In a prospective, randomized, single-blind study, 90 children [ages 7-14 years] were allocated to receive peribulbar block [n = 45] or intravenous fentanyl 1 mg/kg [n = 45] after the induction of general anesthesia. The number of children requiring intraoperative supplemental analgesia, number of incidence of oculocardiac reflex, requirement for additional analgesic, postoperative pain intensity, emetic episodes and parental assessment of the child's postoperative comfort at 24 hours were compared. The study concluded that peribulbar block appears to be safer and of a clinical superiority over the use of intravenous fentanyl for pediatric VR surgery