The crystalline lens is a transparent,biconvex structure in the eye that,along with the cornea,helps to refract light to be focused on the retina and,by changing shape,it adjusts focal distance（accommodation）.The th...The crystalline lens is a transparent,biconvex structure in the eye that,along with the cornea,helps to refract light to be focused on the retina and,by changing shape,it adjusts focal distance（accommodation）.The three classes of structural proteins found in the lens areα,β,and γ crystallins.These proteins make up more than 90% of the total dry mass of the eye lens.Other components which can be found are sugars,lipids,water,several antioxidants and low weight molecules.When ageing changes occur in the lens,it causes a gradual reduction in transparency,presbyopia and an increase in the scattering and aberration of light waves as well as a degradation of the optical quality of the eye.The main changes that occur with aging are： 1） reduced diffusion of water from the outside to the inside of the lens and from its cortical to its nuclear zone; 2）crystalline change due to the accumulation of high molecular weight aggregates and insoluble proteins; 3）production of advanced glycation end products（AGEs）,lipid accumulation,reduction of reduced glutathione content and destruction of ascorbic acid.Even if effective strategies in preventing cataract onset are not already known,good results have been reached in some cases with oral administration of antioxidant substances such as caffeine,pyruvic acid,epigallocatechin gallate（EGCG）,α-lipoic acid and ascorbic acid.Furthermore,methionine sulfoxide reductase A（MSRA） over expression could protect lens cells both in presence and in absence of oxidative stress-induced damage.Nevertheless,promising results have been obtained by reducing ultraviolet-induced oxidative damage.展开更多
·AIM: To obtain widening of a potentially occludable angle, in according to Kanski’s indications, through preventive Nd:Yag laser iridotomy. The observational study was performed by using gonioscopy for the sele...·AIM: To obtain widening of a potentially occludable angle, in according to Kanski’s indications, through preventive Nd:Yag laser iridotomy. The observational study was performed by using gonioscopy for the selection and follow-up of 1165 treated eyes and exploiting Shaffer-Etienne gonioscopic classification as a quality/quantity test of the angle recession.·METHODS: Between September 2000 and July 2012,586 patients were selected at the Outpatients’ Ophthalmological Clinic of the Policlinico Umberto I of Rome in order to undergo Nd: Yag laser iridotomy. A Goldmann type contact lens, Q-switched mode, 2-3defocus, and 7-9 m J intensity with 2-3 impulse discharges were used for surgery.·RESULTS: From as early as the first week, a whole360° angle widening were evident in the patients, thus showing the success of Nd:Yag laser iridotomy in solving relative pupil block. The angle remained narrow by 270° in 14 eyes only, despite repetitions of further treatment with laser iridotomy in a different part of the iris, twice in 10 eyes and three times in 4 eyes.·CONCLUSION: Nd:Yag laser iridotomy revealed itself as being a safe and effective treatment in widening those critical Shaffer-Etienne grade 1 and 2 potentially occludable angles.展开更多
文摘The crystalline lens is a transparent,biconvex structure in the eye that,along with the cornea,helps to refract light to be focused on the retina and,by changing shape,it adjusts focal distance（accommodation）.The three classes of structural proteins found in the lens areα,β,and γ crystallins.These proteins make up more than 90% of the total dry mass of the eye lens.Other components which can be found are sugars,lipids,water,several antioxidants and low weight molecules.When ageing changes occur in the lens,it causes a gradual reduction in transparency,presbyopia and an increase in the scattering and aberration of light waves as well as a degradation of the optical quality of the eye.The main changes that occur with aging are： 1） reduced diffusion of water from the outside to the inside of the lens and from its cortical to its nuclear zone; 2）crystalline change due to the accumulation of high molecular weight aggregates and insoluble proteins; 3）production of advanced glycation end products（AGEs）,lipid accumulation,reduction of reduced glutathione content and destruction of ascorbic acid.Even if effective strategies in preventing cataract onset are not already known,good results have been reached in some cases with oral administration of antioxidant substances such as caffeine,pyruvic acid,epigallocatechin gallate（EGCG）,α-lipoic acid and ascorbic acid.Furthermore,methionine sulfoxide reductase A（MSRA） over expression could protect lens cells both in presence and in absence of oxidative stress-induced damage.Nevertheless,promising results have been obtained by reducing ultraviolet-induced oxidative damage.
文摘·AIM: To obtain widening of a potentially occludable angle, in according to Kanski’s indications, through preventive Nd:Yag laser iridotomy. The observational study was performed by using gonioscopy for the selection and follow-up of 1165 treated eyes and exploiting Shaffer-Etienne gonioscopic classification as a quality/quantity test of the angle recession.·METHODS: Between September 2000 and July 2012,586 patients were selected at the Outpatients’ Ophthalmological Clinic of the Policlinico Umberto I of Rome in order to undergo Nd: Yag laser iridotomy. A Goldmann type contact lens, Q-switched mode, 2-3defocus, and 7-9 m J intensity with 2-3 impulse discharges were used for surgery.·RESULTS: From as early as the first week, a whole360° angle widening were evident in the patients, thus showing the success of Nd:Yag laser iridotomy in solving relative pupil block. The angle remained narrow by 270° in 14 eyes only, despite repetitions of further treatment with laser iridotomy in a different part of the iris, twice in 10 eyes and three times in 4 eyes.·CONCLUSION: Nd:Yag laser iridotomy revealed itself as being a safe and effective treatment in widening those critical Shaffer-Etienne grade 1 and 2 potentially occludable angles.
