ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The past year has produced many advances in our knowledge of experimental and human cataract. Additional information on mechanisms of cataractogenesis has come from in vitro studies. Further investigations of anticataract therapy have been reported this year. Two major pathways to sugar cataract in rats, sorbitol formation and glycation, have been studied. The roles of malondialdehyde, lipid peroxidation, and calcium received further attention as did genetic and ultraviolet-induced cataract. Blood flow, glutathione, and lens proteins are altered in human cataract. Epidemiologic studies this year confirmed the enormous burden of cataract especially in the Third World, and have identified a variety of risk factors. Sugar cataracts in rats could be prevented not only by sorbitol-lowering drugs but also by aspirin, patacetamol, ibuprofen, and by myo-inositol. In humans, aspirin and ibuprofen were associated with protection against cataract, while bendazac was tested in a clinical trial.

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Cataract surgical techniques are constantly evolving and changing, offering the ophthalmologist new and sometimes improved options for optimal visual rehabilitation of their patients. This article reviews the surgical techniques used in cataract surgery with an emphasis on the recent literature. The following areas are covered: anesthesia, incisions and wound closure, capsulotomy, planned extracapsular cataract surgery, phacoemulsification, intraoperative management of the torn posterior capsule, trauma, and combined procedures. The use of phacoemulsification continues to increase in popularity in the developed countries. Small incisions for cataract surgery hasten visual rehabilitation, and continuous circular capsulorhexis has emerged as an advantageous capsulotomy technique. With proper intraoperative management, patients with torn posterior capsules have excellent visual results. Combined procedures allow for concurrent surgery in patients with cataract and coexistent ocular diseases. Cataract surgical techniques must be adapted to suit each patient. The modification of surgical techniques according to individual patient needs and associated ocular and systemic disorders offers a distinct challenge to the ophthalmic surgeon.

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

In reviewing the 1990 literature on intraocular lenses, it is evident that the increased popularity of phacoemulsification in North America has stimulated interest in lens designs that can be inserted through small incisions, and various methods for folding soft lenses. Critical evaluation of various multifocal lenses has now resulted in a greater understanding of their advantages and drawbacks, and it is becoming apparent that there are guidelines of suitable candidates for such lenses. Use of multifocals has stimulated interest in contrast sensitivity testing, and new more accurate lens power formulas. Heparin surface modification of polymethylmethacrylate lenses now seems to be accepted as having some value in reducing pigment deposits after surgery. Clinical trials of lenses for patients suffering from age-related macular degeneration hold some promise for this large group of unhappy patients. However, the use of anterior chamber lenses to correct high myopia in phakic eyes is now on hold because of reports of progressive endothelial cell loss in some eyes. More reports are available on the technique and results of suturing posterior chamber lenses to the sclera where there is absent or insufficient capsule to support a conventional sulcus fixated posterior chamber lens. Intraocular lenses remain alive and well in 1990 with increased usage worldwide.

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

For the most part, cataracts in adults are alike and cataract surgery in adults has become relatively routine. Children with cataracts, however, may have a variety of individual problems that confound the results of successful surgery. Nevertheless, good visual results are attainable with early diagnosis, prompt surgical removal of significant lens opacities, stable optical correction, and occlusion therapy for amblyopia in cases of uniocular cataract. Our best option for stable optical correction in a growing eye is still a contact lens, but studies of intraocular lens implantation and epikeratophakia demonstrate good results in properly selected cases.

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Posterior capsule opacification is a frequent complication of extracapsular cataract extraction (ECCE). Recent efforts aimed at elucidating the mechanism of capsular opacification include demonstration of in vitro fibroblastic transformation of lens epithelial cells and the observation that advanced cataracts have significantly increased epithelial cells when compared to other cataract types which may explain differences in regenerative capability of residual lens epithelium in certain cataracts. Studies on the possible benefits of specific designs and the frequency of posterior capsule opacification suggest that factors such as closer apposition of the lens optic and the posterior capsule via in-the-bag placement of posterior chamber intraocular lenses, use of bag fixated silicone lenses, and use of piano convex/biconvex lens design versus laser ridge or laser “peg” optics have been associated with lower rates of capsular opacification. Despite its potential benefits, damage to the biconvex designed intraocular lens during Nd:YAG (neodymium-yttrium-aluminum-gar-net) laser capsulotomy has been a concern. However, recent data suggests that although laser shots produced tiny visible marks on this IOL, no significant visual symptoms or measurable glare disability manifested that could be attributable to the lens damage.

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Complications of cataract and intraocular lens surgery fall into two groups, sporadic and recurring. Sporadic complications include endophthalmitis and there is evidence that an intact posterior capsule inhibits the inoculant from reaching the vitreous. An acute intraoperative suprachoroidal hematoma occurs in 0.9% of cases, but if this is recognized the visual outcome results are excellent. Recurring problems include astigmatism which is related to the type of incision and the placement of sutures. New incisions reduce astigmatism and the need for sutures. Vitreous loss can be limited in phacoemulsification and vitrectomy should be performed using a bimanual technique. No reliable way to treat aphakic cystoid macular edema yet exists. Postoperative glaucoma and posterior capsule opacification remain a problem. The use of capsulorhexis can lead to pseudomyopia or pseudohyperopia.

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The literature in the past year on refraction is replete with several isolated but very important topics that have been of interest to strabismologists and refractionists for many decades. The refractive changes in scleral buckling procedures include an increase in axial length as well as an increase in myopia, as would be expected. Tinted lenses in dyslexia show little positive effect in the nonasthmatic patients in one study. The use of spectacles or bifocals as a way to control increase in myopia is refuted in another report. It has been shown that in accommodative esotropia not all patients will be able to escape the use of bifocals in the teenage years, even though surgery might be performed. The hope that disposable contact lenses would cut down on the instance of giant papillary conjunctivitis and keratitis has been given some credence, and the conventional theory that sclerosis alone is the cause of presbyopia is attacked. Also, gas permeable bifocal contact lenses are reviewed and the difficulties of correcting presbyopia by this method outlined. The practice of giving an aphakic less bifocal addition instead of a nonaphakic, based on the presumption of increased effective power, is challenged. In the review of prisms, the majority of articles concern prism adaptation. The most significant report is that of the Prism Adaptation Study Research Group (Arch Ophthalmol1990, 108:1248–1256), showing that acquired esotropia in particular has an increased incidence of stable and full corrections surgically in the prism adaptation group versus the control group. Other studies show that adaptation in refractive errors is similar, and the pattern of prism adaptation in normosensory strabismus, cerebellar dysfunction, and in patients with Parkinson's disease is reported. One study shows that measurement of fusion ranges by prisms versus other methods yields different types of information and that fusion with prisms cannot be compared with other methods. The Fresnel versus other conventional prism corrections and the advantages and disadvantages of each are reviewed, along with the aberrations in the two methods of correction.

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Acquired sixth nerve palsy usually results in bothersome symptomatic diplopia. Botulinum toxin injection of the ipsilateral medial rectus is an effective treatment to prevent contracture of this muscle and may provide the patient a functional area of single binocular vision. If recovery of lateral rectus function does not occur in six months, surgery may be required. Transposition of the ipsilateral superior and inferior rectus muscles combined with botulinum injection of the medial rectus may create a large central area of single binocular vision. This procedure avoids surgery on three rectus muscles of the same eye.

ISSN:1040-8738    

出版商:OVID    

年代:1991

数据来源: OVID