Glaucoma e óleo de silicone / Glaucoma and silicone oils

RESUMO O óleo de silicone é um importante tampão utilizado na retinopexia cirúrgica de casos graves de descolamento de retina. O aumento da pressão intraocular e o desenvolvimento de glaucoma secundário são frequentes complicações da sua utilização. A depender do período de aparecimento, diversos mecanismos justificam a ocorrência de tais complicações. Compreender os fatores de riscos e a patogênese do aumento da pressão intraocular associada a aplicação de óleo de silicone em cirurgia retiniana ajuda a orientar o tratamento adequado para cada paciente. O objetivo deste artigo é revisar a literatura sobre a patogenia, a incidência, os fatores de risco e o tratamento desta condição clínica.

ABSTRACT Silicone oil has been an important intraocular tamponade in retinopexy in cases of complicated retinal detachment surgery. The increase of intraocular pressure and development of secondary glaucoma are a known complication of its use. A variety of mechanisms have been proposed for the pathogenesis, depending on the onset. This article aims to review the literature about pathogenesis, the incidence and risk factors, as well as the treatment of this pathology.

Melatonin Prevents Non-image-Forming Visual System Alterations Induced by Experimental Glaucoma in Rats.

Glaucoma is a blindness-causing disease that involves selective damage to retinal ganglion cells (RGCs) and their axons. A subset of RGCs expressing the photopigment melanopsin regulates non-image-forming visual system functions, such as pupillary light reflex and circadian rhythms. We analyzed the effect of melatonin on the non-image-forming visual system alterations induced by experimental glaucoma. For this purpose, male Wistar rats were weekly injected with vehicle or chondroitin sulfate into the eye anterior chamber. The non-image-forming visual system was analyzed in terms of (1) melanopsin-expressing RGC number, (2) anterograde transport from the retina to the olivary pretectal nucleus and the suprachiasmatic nuclei, (3) blue- and white light-induced pupillary light reflex, (4) light-induced c-Fos expression in the suprachiasmatic nuclei, (5) daily rhythm of locomotor activity, and (6) mitochondria in melanopsin-expressing RGC cells. Melatonin prevented the effect of experimental glaucoma on melanopsin-expressing RGC number, blue- and white light-induced pupil constriction, retina-olivary pretectal nucleus, and retina- suprachiasmatic nuclei communication, light-induced c-Fos expression in the suprachiasmatic nuclei, and alterations in the locomotor activity daily rhythm. In addition, melatonin prevented the effect of glaucoma on melanopsin-expressing RGC mitochondrial alterations. These results support that melatonin protected the non-image-forming visual system against glaucoma, probably through a mitochondrial protective mechanism.

Ocular hypertension following 40 mg sub-Tenon triamcinolone versus 0.7 mg dexamethasone implant versus 2 mg intravitreal triamcinolone.

OBJECTIVE: To compare rates of ocular hypertension (OHT) in eyes receiving 40 mg sub-Tenon triamcinolone (STT), 0.7 mg dexamethasone implant (DEX), and 2 mg intravitreal triamcinolone (IVT). METHODS: This study is a single-centre, retrospective case series. All patients receiving STT and DEX between 4/1/2014 and 3/1/2017 and IVT between 3/1/2012 and 3/1/2017 with a minimum of 3 months' follow-up were included. OHT was defined as an intraocular pressure (IOP) >24 mm Hg. Patients receiving any other form of topical, oral, or intravitreal steroid were excluded. RESULTS: 113 eyes from 104 patients in the STT group, 122 eyes from 109 patients in the DEX group, and 109 eyes from 103 patients in the IVT group were included. The mean number of injections for each eye was 1.7 in the STT group, 2.6 for the DEX group, and 2.8 for the IVT group (p < 0.001). Twenty eyes (17.7%) developed OHT in the STT group, 19 eyes (15.6%) developed OHT in the DEX group, and 14 eyes (12.8%) developed OHT in the IVT group (p = 0.60). IOP was controlled in all eyes with observation, topical IOP-lowering medication, or surgical intervention. The rate of incisional glaucoma surgery was 1.7% in the STT group, 1.6% in the DEX group, and 0% in the IVT group (p = 0.55). CONCLUSIONS: The rate of OHT was similar across treatment groups. The proportion of OHT in patients with a history of glaucoma was no different from that in patients without a history of glaucoma. All cases were successfully managed with observation, medical treatment, or incisional surgery.

Ocular Inserts for Sustained Release of the Angiotensin-Converting Enzyme 2 Activator, Diminazene Aceturate, to Treat Glaucoma in Rats.

The aim of this study was to develop and evaluate the effects of chitosan inserts for sustained release of the angiotensin-converting enzyme 2 (ACE2) activator, diminazene aceturate (DIZE), in experimental glaucoma. Monolayer DIZE loaded inserts (D+I) were prepared and characterized through swelling, attenuated total reflectance Fourier transformed infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) and in vitro drug release. Functionally, the effects of D+I were tested in glaucomatous rats. Glaucoma was induced by weekly injections of hyaluronic acid (HA) into the anterior chamber and intraocular pressure (IOP) measurements were performed. Retinal ganglion cells (RGC) and optic nerve head cupping were evaluated in histological sections. Biodistribution of the drug was accessed by scintigraphic images and ex vivo radiation counting. We found that DIZE increased the swelling index of the inserts. Also, it was molecularly dispersed and interspersed in the polymeric matrix as a freebase. DIZE did not lose its chemical integrity and activity when loaded in the inserts. The functional evaluation demonstrated that D+I decreased the IOP and maintained the IOP lowered for up to one month (last week: 11.0 ± 0.7 mmHg). This effect of D+I prevented the loss of RGC and degeneration of the optic nerve. No toxic effects in the eyes related to application of the inserts were observed. Moreover, biodistribution studies showed that D+I prolonged the retention of DIZE in the corneal site. We concluded that D+I provided sustained DIZE delivery in vivo, thereby evidencing the potential application of polymeric-based DIZE inserts for glaucoma management.

Ischemic tolerance protects the rat retina from glaucomatous damage.

Glaucoma is a leading cause of acquired blindness which may involve an ischemic-like insult to retinal ganglion cells and optic nerve head. We investigated the effect of a weekly application of brief ischemia pulses (ischemic conditioning) on the rat retinal damage induced by experimental glaucoma. Glaucoma was induced by weekly injections of chondroitin sulfate (CS) in the rat eye anterior chamber. Retinal ischemia was induced by increasing intraocular pressure to 120 mmHg for 5 min; this maneuver started after 6 weekly injections of vehicle or CS and was weekly repeated in one eye, while the contralateral eye was submitted to a sham procedure. Glaucoma was evaluated in terms of: i) intraocular pressure (IOP), ii) retinal function (electroretinogram (ERG)), iii) visual pathway function (visual evoked potentials, (VEPs)) iv) histology of the retina and optic nerve head. Retinal thiobarbituric acid substances levels were assessed as an index of lipid peroxidation. Ischemic conditioning significantly preserved ERG, VEPs, as well as retinal and optic nerve head structure from glaucomatous damage, without changes in IOP. Moreover, ischemia pulses abrogated the increase in lipid peroxidation induced by experimental glaucoma. These results indicate that induction of ischemic tolerance could constitute a fertile avenue for the development of new therapeutic strategies in glaucoma treatment.

Effect of experimental glaucoma on the non-image forming visual system.

Glaucoma is a leading cause of blindness worldwide, characterized by retinal ganglion cell degeneration and damage to the optic nerve. We investigated the non-image forming visual system in an experimental model of glaucoma in rats induced by weekly injections of chondroitin sulphate (CS) in the eye anterior chamber. Animals were unilaterally or bilaterally injected with CS or vehicle for 6 or 10 weeks. In the retinas from eyes injected with CS, a similar decrease in melanopsin and Thy-1 levels was observed. CS injections induced a similar decrease in the number of melanopsin-containing cells and superior collicular retinal ganglion cells. Experimental glaucoma induced a significant decrease in the afferent pupil light reflex. White light significantly decreased nocturnal pineal melatonin content in control and glaucomatous animals, whereas blue light decreased this parameter in vehicle- but not in CS-injected animals. A significant decrease in light-induced c-Fos expression in the suprachiasmatic nuclei was observed in glaucomatous animals. General rhythmicity and gross entrainment appear to be conserved, but glaucomatous animals exhibited a delayed phase angle with respect to lights off and a significant increase in the percentage of diurnal activity. These results indicate the glaucoma induced significant alterations in the non-image forming visual system.

Topiramato versus Glaucoma Agudo de Ângulo Fechado / Topiramate versus Angle- Closure Glaucoma

Topiramato é um tipo de sulfa monossacarídica de uso oral usado primariamente como anticonvulsivante e não apresenta relação estrutural com outros agentes antiepilépticos. Esta medicação anti-epiléptica de amplo espectro também tem sido usada no manejo de enxaqueca, depressão e dor neuropática. Desde a sua aprovação como anticonvulsivante, diversos relatos tem sido publicados relacionando-o a efeitos oftalmológicos adversos. Os achados patológicos incluem glaucoma secundário a fechamento de ângulo, miopia transitória, hiperemia ocular, efusões uveais, podendo ou não estar presente midríase.

Topiramate is a kind of sulfamate-substituted monosaccharide of oral presentation to be used primarily as an anticonvulsant and it doesn't have structural relation with any other antiepileptic agents. This wide range antiepileptic drug has been used in the management of migraine, depression and neuropathic pain. Since it was approved as an anticonvulsant, many reports related to ophthalmological adverse effects have been published. The pathological findings include secondary angle closure glaucoma, transitory myopia, ocular hyperemia, uveal effusions, with or without mydriasis.

Effect of ocular hypertension on retinal GABAergic activity.

Glutamate and gamma-aminobutyric acid (GABA) are major excitatory and inhibitory retinal neurotransmitters. The balance between these signals is a key principle of organization at retinal level. Although glutamate-induced excitotoxicity could mediate retinal ganglion cell death in glaucoma, the GABAergic system was not previously examined in this disease. The aim of this work was to study the retinal GABAergic activity in eyes with ocular hypertension induced by hyaluronic acid (HA). For this purpose, weekly injections of HA were performed unilaterally in the rat anterior chamber, whereas the contralateral eye was injected with saline solution. At 3 weeks of treatment with HA, GABA turnover rate, glutamic acid decarboxylase activity, and both glutamate- and high K(+)-induced GABA release significantly decreased, whereas GABA uptake increased in HA-treated eyes. The binding of t-butylbicyclophosphorothionate (TBPS) to GABA(A)/benzodiazepine Cl(-) channels significantly increased in eyes injected with HA as compared with vehicle-injected eyes. Changes in GABA uptake and TBPS binding persisted at 6 weeks of treatment with HA. These results indicate a dysfunction of the retinal GABAergic activity in hypertensive eyes, which could suggest the involvement of GABA in glaucomatous neuropathy.

[Iris prosthesis in traumatic aniridia as an attempt to control refractory glaucoma induced by silicone oil in the anterior chamber: case report]. / Prótese de íris, na aniridia traumática, como tentativa de controlar glaucoma refratário provocado pela presença de óleo de silicone na câmara anterior: relato de caso.

The objective of this report is to demonstrate the effectiveness of an iris prosthesis to treat a refractory glaucoma induced by silicone oil in the anterior chamber. This case is about a patient who suffered a trauma caused by firearm shrapnel. A vitreous-retinal surgery was performed to remove intraocular foreign matter and to realign the retina that was detached. Due to the partial traumatic aniridia, silicone oil that was introduced in the vitreous chamber to keep the retina in place migrated to the anterior chamber, resulting in the decrease of endothelium cells and uncontrollable intraocular pressure. We performed transscleral fixation of the iris prosthesis to correct these problems. After a 45-month period of evolution, sight became stable at the 1 meter finger-count distance and intra-ocular pressure at 14 mmHg We may conclude that the triad that consists of lack of: iris diaphragm, aphakia and silicone oil that could not be removed because of inexorable occurrence of detachment of the retina should lead the surgeon to consider transscleral fixation of the iris prosthesis. This procedure might control intraocular pressure and/or preserve corneal transparency, preventing silicone oil from contact with the trabecular net and the corneal endothelium.

Prótese de íris, na aniridia traumática, como tentativa de controlar glaucoma refratário provocado pela presença de óleo de silicone na câmara anterior: relato de caso / Iris prosthesis in traumatic aniridia as an attempt to control refractory glaucoma induced by silicone oil in the anterior chamber: case report

O objetivo deste trabalho é demonstrar a eficácia da prótese iriana na resolução do glaucoma refratário, provocado pela presença de óleo de silicone na câmara anterior. Trata-se de paciente que sofreu trauma por estilhaços de projétil de arma de fogo. A cirurgia vítreo-retiniana visou a remoção dos corpos estranhos intra-oculares e posicionamento da retina, que se encontrava descolada. Devido à ausência parcial do tecido iriano e a afacia, o óleo de silicone introduzido na câmara vítrea, para manter a retina colada, migrou para a câmara anterior e provocou gradativa diminuição do número de células endoteliais e aumento da pressão intra-ocular incontrolável clinicamente. Optamos pela fixação transescleral da prótese de íris para corrigir tais complicações. Após 45 meses de evolução, a acuidade visual estabilizou-se em conta dedos a 1 metro e a pressão intra-ocular em 14 mmHg. Concluímos que a tríade composta pela ausência do diafragma iriano, afacia e impossibilidade da remoção do óleo de silicone, devido a inexorável recorrência de descolamento de retina, deve levar o cirurgião a ponderar sobre a fixação transescleral da prótese de íris. Esta conduta poderá controlar a pressão intra-ocular e/ou preservar a transparência corneana, impedindo o contato do óleo de silicone com a malha trabecular e com o endotélio corneano.

Catarata y glaucoma secundarios glucocorticoides / Cataracts and glaucoma due to corticosteroids

Los glucocorticoides han demostrado ser sumamente útiles en muchos padecimientos, pero también pueden propiciar patologías oculares como son cataratas o glaucoma al ser administrados por un tiempo prolongado o a dosis altas. Se ha demostrado una incidencia mayor en niños o jóvenes asmáticos o con artritis reumatoide. Las cataratas en su inicio se comportan de una forma característica, apareciendo una opacidad subcapsular posterior, pero fácilmente puede confundirse con las causadas por radiaciones ultravioletas, diabéticas (metabólicas) o seniles, aunque los antecedentes nos indican clinicamente la diferencia. El glaucoma inducido por los glucocorticoides también se debe a la aplicación prolongada y a la dosis. Un factor importante que debemos tomar en cuenta son los antecedentes hereditarios del glaucoma primario de ángulo abierto, que propician su aparición y desaparecen en algunos casos al suspender los glucocorticoides. En otros casos se tendrá que administrar tratamiento antiglaucomatoso. Eventualmente puede ser necesaria un intervención quirúrgica. Se hace relevante la necesidad de hacer un exhaustivo estudio previo a los pacientes cuando se requiera de la administración de glucocorticoides, y durante su administración se debe realizar un seguimiento oftalmológico adecuado que implique una exploración con lámpara de hendidura, campimetrías, tonomemtrías y evaluación de fondo de ojo con frecuencia trimestral

Glaucoma cortisônico pseudo-congênito: análise clínica de 33 pacientes / The corticosteroid-induced pseudocongenital glaucoma: clinical analysis of thirty-three patients

Trinta e três crianças (dezesseis do sexo masculino e dezessete do sexo feminino), com idade variando entre dois a quinze meses e história de uso de corticósteroides, foram examinadas no serviço de glaucoma do Hospital Säo Geraldo, de 1976 a 1996. O propósito deste estudo foi estabelecer o quadro clínico do glaucoma cortisônico pseudo-congênito, de acôrdo com os dados obtidos nos exames de rotina. Cinquenta e cinco olhos foram expostos aos corticosteróides e quarenta desenvolveram aumento da Po. O tempo de uso foi de 2,7 ñ 1,8 meses (a idade no início da exposiçäo dos corticosteróides foi de 1,2 ñ 1,7 meses). Os corticosteróides foram prescritos para tratamento de epífora e conjuntivite em 94 por cento dos olhos. O intervalo médio entre o ínicio do uso e a época na qual o glaucoma foi notado variou de cinco dias a um ano, com média de quatro meses. Os corticosteróides mais frequentemente usados foram a dexametasona e betametasona. A história familiar para glaucoma congênito foi negativa. As crianças foram examinadas sob anestesia geral, em máscara aberta, com o uso do metoxifluorano, até junho de 1990, e depois halotano. O exame oftalmológico obedecia a seguinte rotina: tonometria de aplanaçäo, medida do diâmetro corneano horizontal, ecobiometria, biomicroscopia, gonioscopia e biomicroscopia do fundo de olho. Os olhos apresentaram-se claros e sem secreçäo. No primeiro exame, a Po foi estatisticamente maior nos olhos que apresentavam glaucoma. Na maioria dos casos, um aumento nos diâmetros oculares (corneano em 95 por cento e axial em 81,8 por cento) foi encontrado. A biomicroscopia mostrou alteraçöes corneanas (edema corneano e/ou rupturas da membrana de Descemet em 95 por cento), enquanto a íris e o cristalino eram normais. Na gonioscopia, o seio camerular era normal, com parede externa completamente livre. A relaçäo C/D foi maior que 0,5 em 70 por cento dos olhos no primeiro exame. A interrupçäo do corticosteróides, só ou associada a tratamento médico, normalizou a pressäo em alguns olhos (quatro olhos). A trabeculotomia foi a cirurgia da escolha: a Po foi normalizada em todos os olhos nos quais foi ela executada.

Glaucoma cortisônico pseudo-congênito: I. Estudo Clínico de 16 casos (20 olhos) / Corticosteroid-induced glaucoma pseudo congenital

Säo estudados no presente trabalho 16 casos (20 olhos) de glaucoma cortisônico pseudo-congênito. Após breve resenha histórica, os autores descrevem suas observaçöes realçando o seguinte: 1. O uso indiscriminado de colírios contendo corticosteróides em recém-nascidos e lactantes também pode causar glaucoma como no adulto. 2. Aqui também a automedicaçäo é freqüente. 3. A gonioscopia, em geral, e a biomicroscopia näo mostram alteraçöes típicas de glaucoma congênito nesses olhos em relaçäo ao seio camerular e à íris. Entretanto, em dois (10%) dos vinte olhos, foram encontradas alteraçöes gonioscópicas típicas do glaucoma congênito (um olho com persistência exuberante do sistema reticular e outro com aplasia do sistema reticular). 4. Como no adulto, a interrupçäo do colírio de corticosteróide associada ao tratamento clínico pode curar o glaucoma em alguns casos. 5. A trabeculotomia dá bons resultados quando for indicado o tratamento cirúrgico. 6. Teoricamente näo há indicaçäo para se realizar a goniotomia nesses casos

Método simplificado para o desenvolvimento do glaucoma experimental / Simplified method for development of experimental glaucoma

A injeçäo na câmara anterior de olhos de coelhos, de hemácias autólogas fixadas em glutaraldeído determina um aumento constante e duradouro da pressäo intra-ocular. A técnica cirúrgica utilizada determina uma diminuiçäo estatisticamente significante da pressäo intra-ocular