Glaucoma in dogs and cats - management with cyclocryotherapy

Background: The treatment of glaucoma often requires numerous therapeutic modalities to achieve the desired reduction in intraocular pressure (IOP). Cyclodestructive procedures or ciliary body destruction have been performed using techniques with considerable differences in efficacy and complication rates. Among these methods, cyclocryotherapy is non-invasive and simple for the management of uncontrolled glaucoma in dogs and cats. The objective of this case report is to describe the technique of carbon dioxide cyclocryotherapy to reduce intraocular pressure in dogs and cats with glaucoma. Cases: Nine canine patients and one cat with glaucoma were treated with cyclocryotherapy performed under general anaesthesia. Clinical signs patients included blepharospasm, ocular pain, episcleral congestion and ocular hypertension. The patients showed higher levels of IOP, higher than 30 mmHg. Surgical treatment with general anaesthesia was applied. The pre-anaesthesia protocol included acepromazine 0.05 mg/kg with methadone 0.2 mg/kg, followed by intravenous propofol and maintenance with isoflurane and oxygen. An ophthalmological cryocautery unit was used with carbon dioxide as the cryogenic agent and a retinal cryoprobe of 3.2 mm diameter tip for the procedure. The method used was a double cycle of freezing and thawing for 60 s in each site. The cryoprobe was centred approximately 5 mm posterior to the corneoscleral limbus over the ciliary body. The temperature of each cyclocryotherapy spot was between -60°C and -80°C and each site was maintained in place for 60 s; 4 to 6 spots of the double freeze-thaw cycle were made. This technique did not have any serious complications during or after the application of cryotherapy, but chemosis and hyperaemia of the bulbar conjunctiva developed. Subconjunctival anti-inflammatory steroids were injected to minimise swelling and patient discomfort. Satisfactory results were observed; in all cases, the intraocular pressure decreased, with the usual result being a cosmetic and painless eye. Discussion: Even with recent surgical and medical advances, pain and blindness are still common occurrences in glaucoma in human and veterinary practice. The cyclodestructive procedures included cyclodialysis, cyclodiathermy, cyclocryotherapy, and cyclophotocoagulation. The cryosurgery in veterinary ophthalmology has many indications for the treatment of ocular diseases and is effective at decreasing intraocular pressure in patients with persistent uncontrolled glaucoma. Cyclocryotherapy has been shown to reduce intraocular pressure in dogs, cats, rabbits and humans with normotensive and glaucomatous eyes. The application of a cryoprobe over the ciliary processes results in ablating ciliary tissue so that aqueous humour inflow is reduced to acceptable levels. In the clinical cases evaluated, there was a reduction in intraocular pressure reaching acceptable levels, with the usual result being cosmetic and painless eye. Medical therapy remains the predominant method for treating glaucoma in veterinary patients; therefore, cyclocryotherapy is an effective, simple way to lower IOP and is a reasonable treatment option for glaucoma management. Cyclocryotherapy has shown good results, with a low learning curve and it can also be repeated if necessary.

Glaucoma, apoptosis y sildenafil: comprensión de una enfermedad sin solución y un posible enfoque de tratamiento / Glaucoma, apoptose e sildenafil: compreensão de uma doença sem solução e uma possível abordagem de tratamento / Glaucoma, apoptosis and sildenafil: comprehension of a disease without solution and a possible approach of treatment

Millones de pacientes con glaucoma pierden la visión, por lo que es una necesidad para desarrollar terapias neuroprotectoras que pueden utilizarse en conjunción con medicamentos hipotensores, para prevenir la muerte de las células ganglionares de la retina (CGR). Los recientes avances en la comprensión de la fisiopatología de glaucoma es un factor clave en la patogénesis de la neuropatía glaucomatosa. Con base en los hallazgos en enfermedades similares, la hipótesis de que la mejora del flujo sanguíneo de la retina nervio óptico puede dar lugar a una protección significativa en CGR y prevenir la pérdida de visión en el glaucoma. Sildenafil, un fármaco vasodilatador que inhibe la PDE5, lo que aumenta los niveles de cGMP y la prolongación de sus efectos, y se ha demostrado que mejora la supervivencia de diversas lesiones degenerativas. Esta breve revisión resume los avances más importantes que tenían el conocimiento de esta enfermedad y su posible tratamiento.(AU)

Milhões de pacientes com glaucoma irão perder a visão, tornando-se uma necessidade desenvolver terapias neuroprotetoras que possam ser usadas, em conjunção com medicamentos hipotensores, para impedir a morte de células ganglionares da retina (CGR). Recentes avanços na compreensão da fisiopatologia do glaucoma são um fator chave na patogênese da neuropatia glaucomatosa. Com base nos achados em doenças semelhantes, a hipótese de que melhorando o fluxo sanguíneo do nervo óptico da retina possa resultar em uma proteção significativa nas CGR e prevenir a perda da visão no glaucoma. O sildenafil, uma droga vasodilatadora que inibe PDE5, aumentando assim os níveis de cGMP e prolongando seus efeitos, sendo que foi demonstrado melhorar a sobrevivência de várias lesões degenerativas. Esta breve revisão resume alguns dos avanços mais importantes que tiveram no entendimento sobre esta doença e um possível tratamento.(AU)

As millions of glaucoma patients lose sight, it has become accepted that there is a need to develop neuroprotective therapies that can be used, in conjunction with hypotensive drugs, to prevent retinal ganglion cell (RGC) death. Recent advances in the understanding of the pathophysiology of glaucoma is a key factor in the pathogenesis of glaucomatous neuropathy. Based on findings in similar diseases, hypothesize that improving retinal and optic nerve blood flow can result in significant RGC protection and prevent vision loss in glaucoma. Sildenafil, a vasodilative drug that inhibits PDE5, thereby increasing cGMP levels and prolonging NO effects, has been shown to improve survival in several injury. This short review briefly summarizes some of the most important advances that have taken in the understand about this disease and a possible treatment.(AU)

Glaucoma, apoptosis y sildenafil: comprensión de una enfermedad sin solución y un posible enfoque de tratamiento / Glaucoma, apoptose e sildenafil: compreensão de uma doença sem solução e uma possível abordagem de tratamento / Glaucoma, apoptosis and sildenafil: comprehension of a disease without solution and a possible approach of treatment

Millones de pacientes con glaucoma pierden la visión, por lo que es una necesidad para desarrollar terapias neuroprotectoras que pueden utilizarse en conjunción con medicamentos hipotensores, para prevenir la muerte de las células ganglionares de la retina (CGR). Los recientes avances en la comprensión de la fisiopatología de glaucoma es un factor clave en la patogénesis de la neuropatía glaucomatosa. Con base en los hallazgos en enfermedades similares, la hipótesis de que la mejora del flujo sanguíneo de la retina nervio óptico puede dar lugar a una protección significativa en CGR y prevenir la pérdida de visión en el glaucoma. Sildenafil, un fármaco vasodilatador que inhibe la PDE5, lo que aumenta los niveles de cGMP y la prolongación de sus efectos, y se ha demostrado que mejora la supervivencia de diversas lesiones degenerativas. Esta breve revisión resume los avances más importantes que tenían el conocimiento de esta enfermedad y su posible tratamiento.

Milhões de pacientes com glaucoma irão perder a visão, tornando-se uma necessidade desenvolver terapias neuroprotetoras que possam ser usadas, em conjunção com medicamentos hipotensores, para impedir a morte de células ganglionares da retina (CGR). Recentes avanços na compreensão da fisiopatologia do glaucoma são um fator chave na patogênese da neuropatia glaucomatosa. Com base nos achados em doenças semelhantes, a hipótese de que melhorando o fluxo sanguíneo do nervo óptico da retina possa resultar em uma proteção significativa nas CGR e prevenir a perda da visão no glaucoma. O sildenafil, uma droga vasodilatadora que inibe PDE5, aumentando assim os níveis de cGMP e prolongando seus efeitos, sendo que foi demonstrado melhorar a sobrevivência de várias lesões degenerativas. Esta breve revisão resume alguns dos avanços mais importantes que tiveram no entendimento sobre esta doença e um possível tratamento.

As millions of glaucoma patients lose sight, it has become accepted that there is a need to develop neuroprotective therapies that can be used, in conjunction with hypotensive drugs, to prevent retinal ganglion cell (RGC) death. Recent advances in the understanding of the pathophysiology of glaucoma is a key factor in the pathogenesis of glaucomatous neuropathy. Based on findings in similar diseases, hypothesize that improving retinal and optic nerve blood flow can result in significant RGC protection and prevent vision loss in glaucoma. Sildenafil, a vasodilative drug that inhibits PDE5, thereby increasing cGMP levels and prolonging NO effects, has been shown to improve survival in several injury. This short review briefly summarizes some of the most important advances that have taken in the understand about this disease and a possible treatment.