RESUMEN
YAG-laser interventions are associated with the risk of complications, including in the cornea. PURPOSE: This study evaluates the condition of the cornea after laser discission (LD) of secondary cataracts (SC) and laser iridectomy (LI) using corneal confocal microscopy (CCM). MATERIAL AND METHODS: Group 1 included patients with the diagnosis "Pseudophakia, secondary cataract", they underwent LD of SC. Patients of group 1 were divided into 2 subgroups depending on the initial state of the cornea: group 1A included patients with unaltered corneas; group 1B - with changes in the corneas. Group 2 included patients diagnosed with angle-closure glaucoma (ACG) or suspected ACG, they underwent LI. CCM was performed on the Heidelberg HRT-III system. Laser treatment was performed using the Nd:YAG-laser LPULSA SYL-9000, λ=1.064 µm. RESULTS: Immediately after treatment, subgroup 1A exhibited singular hyperreflective deposits and negligible endothelial cell loss (ECL). After 1 month, CMM findings revealed no changes in this subgroup. In subgroup 1B, a post-LD reduction in endothelial cell density led to increased polymegathism, decreased pleomorphism, heightened endothelial cell nucleus reflectivity, and moderate hyperreflective deposits after 1 month. In the second group, significant hyperreflective deposits of various sizes, increased nucleus reflectivity, and notable endothelial cell density reduction were observed immediately and 1 month after LI. CONCLUSION: The results of this study show that the possibility of developing corneal complications after photo destructive laser interventions is to a certain extent related to the initial state of the cornea. The risk of developing corneal damage increases with decreasing distance between the cornea and the irradiated structure. An increase in the level of laser radiation energy and its total values also contributes to damage to the cornea, which is possible with dense secondary cataracts and thick irises.
Asunto(s)
Córnea , Láseres de Estado Sólido , Microscopía Confocal , Humanos , Femenino , Masculino , Córnea/cirugía , Córnea/patología , Córnea/diagnóstico por imagen , Córnea/efectos de la radiación , Anciano , Microscopía Confocal/métodos , Láseres de Estado Sólido/uso terapéutico , Láseres de Estado Sólido/efectos adversos , Terapia por Láser/métodos , Terapia por Láser/efectos adversos , Persona de Mediana Edad , Catarata/etiología , Catarata/diagnóstico , Glaucoma de Ángulo Cerrado/etiología , Glaucoma de Ángulo Cerrado/diagnóstico , Glaucoma de Ángulo Cerrado/cirugía , Glaucoma de Ángulo Cerrado/fisiopatología , Iridectomía/métodos , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/prevención & control , Extracción de Catarata/efectos adversos , Extracción de Catarata/métodos , Segmento Anterior del Ojo/diagnóstico por imagenRESUMEN
The article summarizes the experience of recent years in the development and implementation of novel original laser technologies used in surgery of the anterior segment of the eye. The presented technology of laser activation of scleral hydropermeability (LASH) in glaucoma is based on the effect of enhanced transscleral filtration and has been shown as effective and safe, which was confirmed by the results of a comprehensive clinical and experimental study. Development of another technique was associated with the need to improve the safety of laser interventions in anterior capsule contraction syndrome in pseudophakia, and resulted in a proposition to change the configuration of the anterior lens capsule incision from the usual linear-radial to T-shaped laser anterior capsulorhexis. The proposed technology of laser photomydriasis based on near-infrared radiation of the diode laser (0.810 µm) has shown its effectiveness and gentle nature (absence of atrophy of the iris stroma and post-burn pigmentation) in ectopias and pupil deformity.
Asunto(s)
Segmento Anterior del Ojo , Terapia por Láser , Humanos , Segmento Anterior del Ojo/diagnóstico por imagen , Segmento Anterior del Ojo/cirugía , Iris/cirugía , Terapia por Láser/efectos adversos , Terapia por Láser/métodos , Capsulorrexis/métodos , Seudofaquia/cirugíaRESUMEN
Laser photodestruction (LPD) of tissues is the basis of modern laser reconstructive surgery in ophthalmology. The most common laser technologies based on LPD mechanisms include YAG laser capsulotomy (discission) (LD) of secondary cataract and YAG laser iridectomy (LIE) for glaucoma. Laser reconstructive interventions for secondary cataract, as well as LIE, have a number of advantages over traditional surgery, but at the same time are associated with the risk of complications, including in the cornea. Corneal endothelium is the most susceptible to laser damage, while Descemet's membrane and corneal stroma are injured less often. This review describes cases of iatrogenic perforation and purulent inflammation of the cornea. In the long-term, laser interventions can lead to bullous keratopathy and corneal graft rejection. At this time, the most popular and available among the methods for assessing the cornea after YAG laser interventions is the method of specular microscopy. Ultrasound biomicroscopy is used less commonly. The modern method of corneal confocal microscopy is practically not used for this purpose, and taking into account the risks of developing laser-induced injuries, it indicates its relevance and the need for further research.
Asunto(s)
Opacificación Capsular , Terapia por Láser , Láseres de Estado Sólido , Humanos , Córnea/diagnóstico por imagen , Córnea/cirugía , Terapia por Láser/efectos adversos , Endotelio CornealRESUMEN
YAG laser interventions are associated with the risk of complications, including corneal. PURPOSE: To study the mechanisms of laser destruction in exposing the posterior lens capsule (PLC) tissue to Nd:YAG laser irradiation, and to evaluate its side effects on the cornea. MATERIAL AND METHODS: The experiment involved 6 autopsy samples of human posterior lens capsule with different optical and mechanical properties, which were exposed to laser irradiation. We used the Nd:YAG ophthalmic laser LPULSA SYL-9000 Premio manufactured by «LightMed¼ (Taiwan/USA) and an experimental Nd:YAG laser system (1.064 µm). The following parameters were compared: the power of the incident radiation and radiation transmitted through the PLC, the mechanical stresses in the PLC tissue, the kinetic energy of the laser ablation products, and the pressure of gas bubbles during laser exposure in capsule samples of different densities. In the clinical part of the work, the negative effects of Nd:YAG laser on the cornea at different PLC densities were assessed using the endothelial microscope SP 3000P («Topcon¼, Japan). RESULTS: The experiment showed that in hard samples of PLC there are star-shaped point perforations with a diameter of 50±20 µm with partial rarefaction around the point defects. Damage to soft PLC samples in the form of large complete perforations was up to 200 µm in size. The temperature of laser irradiation necessary to achieve breakdown in soft PLC samples was 90 °C, in hard samples - 120 °C. The results of the experiment indicate that the final outcome - destruction of the PLC tissue - is safer to achieve not by increasing the energy, but by increasing the number of laser pulses. Clinical study results confirm a significant effect of the density of PLC on the values of laser energy and on the state of the cornea after laser intervention. CONCLUSION: The experimental data on the mechanisms of laser destruction of the lens capsule should contribute to the development of new and improvement of already known technologies aimed at reducing the risks associated with laser surgeries.
Asunto(s)
Terapia por Láser , Láseres de Estado Sólido , Cápsula del Cristalino , Cápsula Posterior del Cristalino , Humanos , Láseres de Estado Sólido/efectos adversos , Cápsula del Cristalino/cirugía , Terapia por Láser/efectos adversos , Terapia por Láser/métodos , CórneaRESUMEN
In the experiments at Wistar male rats the effect of subtherapeutic doses of docetaxel (5 and 10 mg/kg) on the radiotherapy efficacy (20 Gy of single-dose X-rays) namely growth rate of Guerin's tumor and prooxidant-antioxidant balance in liver and blood of animals bearing tumors was investigated. It has been demonstrated that docetaxel at dose 5 mg/kg given 18 hours before irradiation resulted in significant tumor growth delay (2.3-2.7-fold) in comparison with group of rats that received only irradiation. After application of higher dose of docetaxel there was no statistically significant change of tumor size along the whole experiment (14 and 21 days after tumor implantation). Content of lipid peroxidation products was revealed to be considerably increased after chemotherapy and concurrent irradiation when docetaxel was used in a dose of 10 mg/kg. At the same time glutatione peroxidase activity and antioxidative activity of blood plasma were reduced. In the rat liver chemoradiotherapy led to decrease of glutathion peroxidase and glutathione-S-transferase activity to greater degree at docetaxel dose of 10 mg/kg. The obtained results allow to conclude that higher dose of docetaxel and concurrent irradiation resulted in the most effective Guerin's carcinoma growth delay and considerable deviation of antioxidant-prooxidant balance of tissues in the direction of the last.