人工晶状体材料的研究进展

随着白内障超声乳化吸除联合人工晶状体植入术的广泛应用，许多白内障患者都恢复了有效视力。术后人工晶状体混浊是评价生物相容性的重要指标，它会影响患者的视觉质量，不同材料人工晶状体混浊的表现及危险因素是不同的。然而，获得较好的视觉质量不是由单一因素决定的，人工晶状体的材料、患者对人工晶状体的反应等都是影响术后视觉质量的因素。随着科技的不断进步，越来越多的新材料在人工晶状体领域得到应用，充分了解不同人工晶状体材料的特性，为患者选择合适的人工晶状体，减少材料导致的并发症，将为患者带来福音。本文就不同人工晶状体材料的特性与人工晶状体植入术后发生混浊的表现及危险因素进行探讨。     

"Special" intraocular lens designs: why do they sometimes fail?

A variety of new "special" intraocular lens models to optimize the visual performance after cataract surgery have been introduced. The majority of these new intraocular lens designs require a good centration within the capsular bag and/or capsular elasticity. Today, the main post-operative complications after cataract surgery still arise from retained lens epithelial cells within the capsular bag, resulting mainly in anterior and posterior capsule opacification. Some special intraocular lenses are not designed to be effective against proliferating lens epithelial cells. Although lens epithelial cells can never be completely removed from the capsular bag, surgical quality is a major factor for success or failure of these intraocular lens designs.     

有晶状体眼前房角固定型人工晶状体植入术的进展

有晶状体眼前房角固定型人工晶状体植入术是近年来发展起来的矫正高度和超高度近视的一项新技术，随着晶状体材料的改良和临床经验的积累，这种屈光手术逐渐显示出了安全、有效、预测性好、可逆性、保留调节功能和对角膜内皮损伤小等优点。因此，在未来的几年里，前房角固定型人工晶状体植入术作为一种屈光手术将会扩大它的临床应用范围。就该手术的历史、人工晶状体的设计、手术适应证与禁忌证、手术技术、并发症及其防治等方面进行综述。     

Biological and physical aspects of intraocular pressure

A thorough understanding of intraocular pressure homeostasis is the biological foundation for the development of new strategies to treat patients with elevated intraocular pressure or glaucoma. However, investigations on the physiology of intraocular pressure homeostasis are also important to gain more comprehensive insights into the pathogenesis of glaucoma and other diseases with associated alterations of intraocular pressure. The present review intends to give alternative insights into the biological and physical aspects of intraocular pressure regulation. The pressure-volume as well as the hydraulic model of intraocular pressure and also the relationship between ciliary blood flow and aqueous humor production, which has moved into the centre of interest because of its possible clinical relevance for glaucoma patients, will be explained. The authors Have attempted to interrelate the different aspects of intraocular pressure genesis and regulation in a comprehensive but understandable way.     

Extracapsular cataract extraction with phacoemulsification and pars plana vitrectomy with silicone oil tamponade in one session]

BACKGROUND: In phacic eyes the development of a cataract is induced by silicon oil. In this case the lens has to be removed in a second operation with or without intraocular lens implantation. In cataract surgery a new incision technique is used, which makes it easily possible to combine both operations in one session. METHODS: A feature of the new incision technique is that a scleral tunnel is dissected before the anterior chamber is opened. The opening closes itself, if the intraocular pressure rises. The danger, that a rise in intraocular pressure during the vitrectomy makes an irisprolaps, for example during the substitution of perfluorcarbon by silicon oil, no longer exists. RESULTS: The operation technique and the postoperative course of three patients with intraocular lens implantation and pars-plana-vitrectomy using silicon oil is reported. CONCLUSIONS: By using the new incision technique in cataract surgery intraoperative complications during vitrectomy like an irisprolaps or penetration of silicon oil into the anterior chamber no longer exist. In selected cases one operation is saved for the patient.     

Technical construction, calibration and results with a new intraocular pressure sensor with telemetric transmission]

BACKGROUND: Presently intraocular pressure is measured indirectly by applanation or impression of the cornea. Only isolated values are available with this method. We present a new implantable system for direct and continuos measurement of the intraocular pressure. METHODS: An implantable system consisting of a miniaturized sensor and a telemetric unit was integrated in an intraocular lens. The eye pressure is determined by the sensor, modulated and transduced by the telemetric system. By an extracorporal receiver the signal is demodulated. The electric supply of the intraocular system is achieved by external electromagnetic induction. RESULTS: The telemetric transmission of the intraocular pressure can be achieved with an accuracy of +/- 1 mm Hg and a frequency of registration of 3 values per second. CONCLUSION: Clinical application necessitates further animal trials in vivo.     

Intravitreal chemotherapy for intraocular lymphoma

Primary CNS and intraocular non-Hodgkin's lymphoma is currently mostly treated with systemic chemotherapy. After initially successful tumor regression, recurrence is common and usually treated with radiotherapy. However, after good primary therapeutic response, new tumor growth is frequently observed. Because of actinic complications, radiotherapy can be applied only once. For an intraocular recurrence of primary CNS and intraocular lymphoma, intravitreal chemotherapy (0.4 mg methotrexate and 0.4 mg dexamethasone weekly for 4 weeks and once a month thereafter) can be performed. A few weeks after initiation, regression of intraocular tumors and eventually improvement of vision can be achieved. Eyes remained free of recurrence up to 2 years after initiation of intravitreal injections. Intravitreal chemotherapy is an effective treatment for ocular recurrence of primary CNS and intraocular lymphoma after systemic chemotherapy and radiotherapy.     

非球面人工晶状体的研究进展

非球面人工晶状体是目前临床上备受关注的一种新型人工晶状体，它具有减轻像差和提高白内障患者术后视觉质量等优点．较传统的球面人工晶状体更能满足人们对高质量视力的要求，因而近年来非球面人工晶状体不断涌现．有望成为未来人工晶状体的主导。本文将从非球面人工晶状体的设计特点、原理、分类、临床应用以及功能评价指标等方面作一综述。     

Biocompatibility of intraocular lens materials

PURPOSE OF REVIEW: To provide an update on currently available materials used in the manufacture of intraocular lenses, as well as new materials under development, especially with regard to their uveal and capsular biocompatibility. RECENT FINDINGS: The biocompatibility of intraocular lens materials should be assessed in terms of uveal biocompatibility, related to the inflammatory foreign-body reaction of the eye against the implant, as well as in terms of capsular biocompatibility, determined by the relationship of the intraocular lens with remaining lens epithelial cells within the capsular bag. This situation may result in different entities, e.g. anterior capsule opacification, interlenticular opacification (between piggyback intraocular lenses), posterior capsule opacification and lens epithelial cell ongrowth. Reports on intraocular lens opacification suggest that the potential to calcify should also be taken into consideration when evaluating the long-term biocompatibility of a new material. SUMMARY: Intraocular lenses are being progressively implanted in much earlier stages of life (refractive lens exchange, pediatric implantation) and are expected to remain in the intraocular environment for many decades. Materials used in intraocular lens manufacture should, therefore, insure long-term uveal and capsular biocompatibility, as well as ultimate transparency after implantation.     

Examinations by ocular pressure tonometry

A new method has recently been suggested for the determination of the outflow resistance in the anterior chamber angle. In this method the intraocular pressure is set to 45 mmHg for 8 minutes. The intraocular pressure is measured after the removal of the suction cup. Values below 7 mmHg are obtained in healthy subjects. Values above 7 mmHg are thought to be indicative for glaucoma. By setting the intraocular pressure to 45 mmHg for the expression of fluid the authors claim to have brought normalization to tonography. We show here in a series of results that we can reproduce the results which have been published by Ulrich et al. For normalization of a tonographic test we need a pressure rise which effects a uniform expression of volume. According to the knowledge presently generally agreed upon a uniform expression of volume is obtained by increasing the intraocular pressure by a constant factor and not by increasing it to a constant level. In 30 healthy volunteers and in 30 glaucoma patients we have increased the intraocular pressure by the constant factor of 1.8. According to our results the glaucoma patients and the healthy subjects can no longer be differentiated. A better differentiation is possible by the initial intraocular pressure. Thus we have shown that the favorable results by ocular pressure tonometry are mainly due to the intraocular pressure before the test. We feel therefore that ocular pressure tonometry should not be incorporated in our diagnostic armamentarium for glaucoma diagnosis.     

Cytology of intraocular lens surface: a transmission electron-microscopic study. Cytology of intraocular lens surface

We developed a new method for specimen preparation for transmission electronmicroscopic study of cellular responses on intraocular lenses. This procedure omits propylene oxide treatment of the materials to be studied, which is normally a step in the routine preparation process for transmission electron microscopy. It was previously found that propylene oxide treatment dissolves intraocular lenses. Using our procedure, two types of cells were identified on intraocular lenses removed from monkey eyes 7 days after implantation. These cells had the typical structural features of multinucleated giant cells and of macrophages. It thus appears that this procedure will permit study of the cytology of intraocular lens surfaces.     

Intraocular pressure assessment after laser in situ keratomileusis: a review

This paper aims to review the current methods available for the measurement of intraocular pressure after myopic laser in situ keratomileusis for the correction of myopia. Searches were performed for studies that assessed or compared various methods of intraocular pressure assessment. There were 20 eligible studies that explored the use of pneumotonometry, pressure phosphene tonometry, rebound tonometry, dynamic contour tonometry, statistical modeling, mathematical formulae, ocular response analyzer and even measuring intraocular pressure on the nasal cornea. Our review shows that an ideal method would be one that is independent of corneal factors. Dynamic contour tonometry and pressure phosphene tonometry held promise in research settings. More studies need to be done to validate the new methods of intraocular pressure assessment, especially in glaucoma patients. It is important to empower laser in situ keratomileusis patients with knowledge of these difficulties and potential implications for the future.     

New techniques and instruments for lens implantation

Although most of the new techniques and new instrumentation for intraocular lens implantation are related to foldable intraocular lenses or sutured posterior chamber lenses, there are some intriguing new concepts in intraocular lens techniques unrelated to these two areas.     

经透明角膜切口可折叠型人工晶状体缝线固定术的临床观察

目的 探讨对囊膜不足以支撑人工晶状体（IOL）的无晶状体眼患者经透明角膜切口行可折叠IOL缝线固定术的临床疗效.方法 回顾性系列病例研究.对14例（14眼）囊膜不足以支撑IOL的无晶状体眼患者由透明角膜切口行可折叠型IOL缝线固定术,观察术中、术后并发症及术后视力情况.结果 所有患者术中未出现并发症.术后裸眼视力均较术前提高,术后最佳矫正视力较术前最佳矫正视力改善或者无变化的共13例（93％）；1例发生玻璃体少量积血,1例出现IOL光学部轻度偏斜,3例出现一过性高眼压.结论 经透明角膜切口行可折叠型IOL缝线固定术是治疗囊膜不足以支撑IOL的无晶状体眼的一种较好选择.     

The familial occurrence of cutaneous melanoma, intraocular melanoma, and the dysplastic nevus syndrome

The occurrence of cutaneous melanoma and intraocular melanoma as double primary cancers in the same patient and in different members of the same family has suggested that these two forms of melanoma are etiologically related. It is theoretically possible that the link between these two pigment cell malignancies may be the dysplastic nevus syndrome, and patients with the dysplastic nevus syndrome may have an increased risk of intraocular melanoma and cutaneous melanoma. We studied two new kindreds in which cutaneous melanoma, intraocular melanoma, and the dysplastic nevus syndrome occurred and conducted neuro-ophthalmologic examinations of 26 patients with hereditary cutaneous melanoma or the dysplastic nevus syndrome, or both. In the one family studied in detail, the cutaneous melanoma predisposition came from the paternal bloodline, whereas the intraocular melanoma occurred in the maternal bloodline. The ophthalmologic examinations disclosed neither intraocular melanoma nor suspicious or atypical choroidal nevi. Our limited data suggested that the association of intraocular melanoma with cutaneous melanoma and dysplastic nevus syndrome may be coincidental.     

Intraocular magnet of Parel.

The intraocular magnet (IOM) is a new device based on permanent magnetism providing controlled energy for removal of magnetic intraocular foreign bodies. Its use is reported in 11 cases.     

Intraocular pressure measurement: A review

Glaucoma is the leading cause of irreversible blindness, affecting around 80 million people worldwide. Glaucoma is a multifactorial disease of poorly understood pathogenesis, with intraocular pressure being the most significant risk factor. Currently there are different methods of intraocular pressure measurement, based on different physical principles, some of which are continuous measurement methods and others which are only measured in the medical office. The importance of the corneal biomechanical properties in intraocular pressure measurement is becoming increasingly clear. With the development of new instruments that can measure them, it will become possible to obtain more accurate intraocular pressure measurements within a short period of time. In the future, glaucoma patients will be better monitored with instruments capable of measuring intraocular pressure 24 hours a day.     

角膜嵌顿眼前段玻璃纤维异物取出新法

目的探讨角膜嵌顿的眼前段玻璃纤维异物的取出新法。方法以1.4mm矛形刀穿刺前房,视玻璃纤维直径及刺入深度,酌情采用眼用粘弹剂或眼内灌注液加深前房,使玻璃纤维自晶状体、虹膜退出或使其前端产生足够的操作空间,然后以自制7#驱逐针头托玻璃纤维后退,以显微持针器轻轻夹持退出部分全部拔除。结果本组7例(7眼)角膜嵌顿的眼前段玻璃纤维异物,全部被安全快捷地取出,无一发生手术误伤及手术并发症,且术后反应均很轻微。结论本手术方法不仅特别适用于取出角膜嵌顿的眼前段玻璃纤维异物,也可用于取出其他类似比较坚挺光滑的异物,如铅笔芯等。对取出比较松软之金属细丝、木刺等异物,有时也有一定帮助。     

A new biconcave contact lens for vitrectomy in eyes with intraocular lens implantation

The authors report a new biconcave contact lens capable of providing superior surgical views of eyes during vitrectomy and intraocular lens implantation under both fluid-filled and air-filled conditions. The new biconcave lens is made of a glass with a high refractive index (nd = 1.883). The lens is placed on the cornea using a regular lens ring for the floating vitrectomy lens system. During vitrectomy, the new biconcave lens provides a view as clear as that of the commercially available flat-concave lens when the vitreous cavity is filled with fluid. The lens also provides a more magnified view than the commercially sold biconcave lens during fluid-air exchange, with no need for replacement. The new biconcave vitrectomy lens spares the surgeon the trouble of replacing different refractive lenses during the fluid-air exchange procedure in an eye undergoing intraocular lens implantation, and may be helpful for vitreous surgery.     

Intraocular lens calculation formulas for new intraocular lens implants

Several different formulas are available for preoperative calculation of the required implant power for a desired postoperative refraction. However, the application of both theoretical and statistically derived regression formulas to the new generation of soft intraocular lens implants poses several difficulties. In this paper the calculation of an A constant for a specific intraocular hydrogel lens implant, as well as the derivation of a universal theoretical formula, is described. The theoretical formula can be applied to other implant styles with various optical configurations and composed of different biomaterials. The SRK and theoretical formulas have been applied retrospectively to a series of patients receiving an intraocular hydrogel lens implant. A comparison shows that both perform satisfactorily in predicting the desired postoperative refraction.