Ophthalmology clinics of North America最新文献

Clinical research has demonstrated the the continuous decline of the contrast sensitivity with age results from increasing spherical aberration of the human crystalline lens. Replacing the crystalline lens with appropriate modeled pseudophakic lens can provide superior contrast sensitivity and functional vision. As advances in the technology allow cataract and refractive surgeons to address higher-order optical aberrations, the measurement of functional vision becomes increasingly critical as a gauge of the progress. Contrast sensitivity testing is assuming a prominent place in the evaluation of surgical modalities because it reflects functional vision, correlates with visual performance, and provide a key to understanding optical and visual processing of images.

Refractive cataract surgery has become a reality for the modern phacosurgeon, and control of astigmatism plays a vital role in this quest for optical refractive outcomes. Fortunately, a number of effective options exist to minimize postoperative cylinder. These include placing the cataract incision on the steep corneal meridians; use of adjunctive corneal or limbal relaxing incisions; or even using advanced technology, such as the excimer laser. Careful attention must be directed to the measurement of pre-existing astigmatism, and a detailed surgical strategy must then be formulated. Finally, one must be able to avail themselves of enhancement techniques to address residual astigmatism.

The incidence of diabetes mellitus is rising. With significant proportion developing cataracts, diabetic surgery comprise an ever-growing subset of people undergoing cataract surgery. Although these patients provide unique challenges to cataract surgeon, early intervention and appropriate preoperative, intraoperative, and postoperative considerations can lend to good outcomes.

The intraoperative management of complication during cataract surgery of vitreous loss and dropped nucleus strongly influences the outcome, and a well-rehearsed plan for both staff and surgeons is needed. Preventative measures, early recognition, damage control, and resolution are discussed in this article. Maintenance of appropriate pressure relationships and tissue planes limits vitreous prolapse and the surgeon's primary goal is to avoid vitreous traction resulting in retinal tears and detachment. A pars plana approach to anterior vitrectomy with staining of the prolapsed vitreous is the most effective technique. Although residual lens material should be removed from the anterior and posterior chambers, once a fragment is lost to the posterior segment, the authors advocate referral for a standard three-port posterior vitrectomy with fragmenter as needed because the goal of the cataract surgeon is to offer the patient a clean, pseudophakic anterior segment and the best chance for an optimal visual recovery.

Cataract is the leading cause of blindness worldwide. Smoking, diabetes, and exposure to UVB light consistently have been identified as risk factors for cataract development. Recently, new factors have been identified. Further research into other previously identified risk factors has suggested that these initial associations ma indeed not exist. This article reviews the current state of knowledge on risk factors for development of age-related cataract formation.

The prevalence of postoperative endophthalmitis following cataract surgery appears to be increasing with the popularity of clear cornea incision. As a result, endophthalmitis prophylaxis will play and increasingly important role as the number of clear cornea cataract surgeries increases. In this article, the authors examine and critically evaluate techniques used to prevent endophthalmitis including proper preoperative patient preparation, application of povidone-iodine, and use of broad-spectrum antibiotics (topical, intracameral, and subconjunctival injection).

The most common surgical procedure in the United States is cataract surgery; most specifically, phacoemulsification. Understanding the fluidics and ultrasonic power fundamentals for phacoemulsification is instrumental for their safe and efficient use. Although phaco machines allow a few decades ago, the basic concepts have remained the same. Phaco machines allow ultrasonic-assisted aspiration of the cataract while maintaining the stability within the eye and minimizing the trauma of surgery to ocular structures. In this light, the two primary concepts are the fluidics of the lens aspiration and the application of the ultrasound power.

Accurate biometry and intraocular lens (IOL) calculations have consequence in patient satisfaction and depend on correct determination of eye length, IOL position, refractive power of the cornea, and selection of the proper IOL formula. Familiarity with these variables will make it easier to achieve precise results in both the intact eyes and eyes that have had previous surgeries, including keratorefractive procedures. This articles provide practical tips and methods to avoid refractive surprises.

There has been a rapid evolution in the field of intraocular lens (IOL) manufacture, much of it influenced by the development of microincision surgical techniques and wavefront aberrometry.Thi article discusses new technology that has been applied to modern IOL optics, including multifocal, toric, blue-blocker, accommodative, and aspheric IOLs; lenses designed to be inserted through sub 2-mm incisions; and an implantable telescope for macular degeneration.

Endocapsular support devices, such as the capsular tension ring, and other newer scleral-fixated devices have become increasingly important in the management of compromised zonules during cataract surgery. Cataract removal in patients with significant zonulopathy presents many challenges with increase risk of intraoperative and postoperative complications. The original capsular tension ring was the beginning of a progressive evolution in the management of zonular weakness. Newer devices, which permit scleral-suture fixation, include the modified capsular tension ring and the capsular tension segment.