Ophthalmol Clin North Am
· 2006 Dec · PMID 17067906
·
Publisher ↗
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 appropria...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.
Ophthalmol Clin North Am
· 2006 Dec · PMID 17067905
·
Publisher ↗
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 remov...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.
Arbisser LB, Charles S, Howcroft M
… +1 more, Werner L
Ophthalmol Clin North Am
· 2006 Dec · PMID 17067904
·
Publisher ↗
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 me...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.
Ophthalmol Clin North Am
· 2006 Dec · PMID 17067903
·
Publisher ↗
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...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.
Ophthalmol Clin North Am
· 2006 Dec · PMID 17067902
·
Publisher ↗
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 techn...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.
Ophthalmol Clin North Am
· 2006 Dec · PMID 17067901
·
Publisher ↗
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 fo...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.
Ophthalmol Clin North Am
· 2006 Dec · PMID 17067900
·
Publisher ↗
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 import...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).
Ophthalmol Clin North Am
· 2006 Dec · PMID 17067899
·
Publisher ↗
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 pro...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.
Ophthalmol Clin North Am
· 2006 Dec · PMID 17067898
·
Publisher ↗
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 uniq...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.
Ophthalmol Clin North Am
· 2006 Dec · PMID 17067897
·
Publisher ↗
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. F...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.
Ophthalmol Clin North Am
· 2006 Sep · PMID 16935215
·
Publisher ↗
A wide variety of mediators likely contribute to ocular NV and these can serve as potential targets for the treatment of ocular NV. Several targets have already been validated in preclinical models and are being explored...A wide variety of mediators likely contribute to ocular NV and these can serve as potential targets for the treatment of ocular NV. Several targets have already been validated in preclinical models and are being explored in clinical studies. In addition, targeting other processes besides angiogenesis, such as inflammation and apoptosis, may be beneficial in the treatment of ocular NV. Combined approaches with the use of several angiogenesis inhibitors or anti-inflammatory agents may show synergistic effects in treating ocular NV.
Ophthalmol Clin North Am
· 2006 Sep · PMID 16935214
·
Publisher ↗
RNA interference is a new technology that allows the production of therapeutic double-stranded RNA molecules (siRNA) that can specifically prevent the production of a particular gene product in a potent and efficient man...RNA interference is a new technology that allows the production of therapeutic double-stranded RNA molecules (siRNA) that can specifically prevent the production of a particular gene product in a potent and efficient manner. It accomplishes this task by activating a native cellular defense mechanism, which when triggered results in the prevention of gene product production before the protein is made. Because of this amplification, only small quantities of siRNA are required to produce a silencing of gene production. siRNA designed to reduce production of angiogenic molecules provides potent therapies for ocular neovascularization in patients with age-related macular degeneration or diabetic retinopathy.
Connolly B, Desai A, Garcia CA
… +2 more, Thomas E, Gast MJ
Ophthalmol Clin North Am
· 2006 Sep · PMID 16935213
·
Publisher ↗
Squalamine lactate inhibits angiogenesis by a long-lived, intracellular mechanism of action. The drug is taken up into activated endothelial cells through caveolae, small invaginations in the cellular membrane. Subsequen...Squalamine lactate inhibits angiogenesis by a long-lived, intracellular mechanism of action. The drug is taken up into activated endothelial cells through caveolae, small invaginations in the cellular membrane. Subsequently, the drug binds to and "chaperones" calmodulin to an intracellular membrane compartment and blocks angiogenesis at several levels. A series of basic investigations, preclinical studies, and human clinical trials have begun to establish the proof of concept, efficacy, and safety parameters for use of squalamine lactate as a therapeutic agent for exudative age-related macular degeneration and several types of malignancies.
Ophthalmol Clin North Am
· 2006 Sep · PMID 16935212
·
Publisher ↗
Although there have been treatments and pharmacologic agents approved in the last several years to treat advanced stages of AMD, these treatments do not halt disease progression. Furthermore, it is clear that when dry AM...Although there have been treatments and pharmacologic agents approved in the last several years to treat advanced stages of AMD, these treatments do not halt disease progression. Furthermore, it is clear that when dry AMD progresses to CNV in one eye, there is a substantial risk that it will progress in the other eye. Sight-preservation at early stages of the disease should be a key goal of research, yet there are no approved therapies for halting the progression of early stages of AMD. Patients may be encouraged to use vitamin supplements, cease smoking, and eat a healthy diet; however, these recommendations are not appropriate for all patients, nor are they embraced by everyone. A pharmacologic agent capable of targeting the early stages of AMD would be a welcome addition to the armamentarium of options for managing AMD. Trials are ongoing to evaluate the role of anecortave acetate as a prophylactic treatment to slow the progression of the early stages of AMD. Completed clinical studies have demonstrated that anecortave acetate possesses a mechanism of action that decreases CNV growth irrespective of the inciting angiogenic stimulus, has a dosing-interval that allows its use as prophylactic therapy, and is safe. The economic benefits associated with prevention and progression to advanced AMD, in even a small proportion of cases, is significant and could result in substantial cost savings to society as a whole while providing countless benefits to individual patients in terms of continued independent function, self-sufficiency, and improved quality of life.
Ophthalmol Clin North Am
· 2006 Sep · PMID 16935211
·
Publisher ↗
Ranibizumab therapy is the first treatment for neovascular AMD to improve vision for most patients. The benefits apply to all angiographic subtypes of neovascular AMD and across all lesion sizes. Although the pivotal pha...Ranibizumab therapy is the first treatment for neovascular AMD to improve vision for most patients. The benefits apply to all angiographic subtypes of neovascular AMD and across all lesion sizes. Although the pivotal phase III trials (MARINA and ANCHOR) used monthly injections of ranibizumab for 2 years, the ongoing PIER, PrONTO, and SAILOR trials are investigating less frequent dosing regimens, and preliminary results from the PrONTO study suggest that fewer injections will most likely result in visual acuity improvements similar to the results from the phase III trials. When comparing the ANCHOR results with the FOCUS results, it also becomes apparent that the combination of ranibizumab with PDT does not necessarily result in better visual acuity outcomes, and the use of PDT may even reduce the visual acuity benefits achieved with ranibizumab alone (see Figs. 1-3). It seems unlikely that combination therapy provides any significant advantage over ranibizumab alone unless the combination of PDT and ranibizumab can decrease the need for frequent retreatment. The results from the PrONTO Study already suggest that less frequent treatment with ranibizumab is possible by using a variable dosing regimen with OCT. Ranibizumab also seems to be safe, with the 2-year MARINA data showing no increase in the incidence of systemic adverse events that could be associated with anti-VEGF therapy, such as myocardial infarction and stroke. There was a hint of a safety concern, however, in the pooled 1-year safety results from the MARINA and ANCHOR trials. Although the combined rate of myocardial infarction and stroke during the first year of the ANCHOR and MARINA trials was similar in the control and the 0.3-mg ranibizumab arms (1.3% and 1.6% respectively), these adverse events were slightly higher in the 0.5-mg ranibizumab arm (2.9%). These differences are not statistically significant, however, and probably do not represent a dose-dependent increase in risk because the 2-year results from the MARINA trial with the same monthly injection regimen showed no increased risk of thromboembolic events. In December 2005, Genentech submitted a Biologics License Application to the FDA for the use of ranibizumab in the treatment of neovascular wet AMD based on 1-year clinical efficacy and safety data from the two pivotal phase III trials, ANCHOR and MARINA, and the phase I-II FOCUS trial. Genentech has been granted a 6-month Priority Review from the FDA with a decision anticipated 6 months from the December submission date or by the end of June 2006 [29]. By the summer of 2006, this revolutionary therapy should be available for the treatment of neovascular AMD. At that time, the major dilemma facing most retina specialists will be whether to use intravitreal ranibizumab or intravitreal bevacizumab, the low cost alternative, for the treatment of neovascular AMD.
Ophthalmol Clin North Am
· 2006 Sep · PMID 16935210
·
Publisher ↗
Repeated Macugen intravitreal injections, well tolerated and safe when performed according to protocol, is the first successful pharmacotherapy for wet AMD. Macugen has already had a significant impact on neovascular AMD...Repeated Macugen intravitreal injections, well tolerated and safe when performed according to protocol, is the first successful pharmacotherapy for wet AMD. Macugen has already had a significant impact on neovascular AMD management, in regard to both individual patients with AMD lesions that would become amenable to treatment, and in its effects on visual function and its preservation in the aging United States population. Although results and delivery method are not optimal, the positive outcomes indicate the beginning, and not the limit, of pharmacotherapy for AMD. The benefits of Macugen therapy for AMD strongly outweigh the risks. It is pointed out by some that the overall magnitude of the efficacy results is very similar to the PDT trials and question why there is so much enthusiasm about a treatment that entails intravitreal injections every 6 weeks instead of PDT every 12 weeks. In all fairness, PDT is not equally efficacious across the lesion subtypes and sizes, whereas Macugen has effect with all lesion subtypes. In addition, these studies widen the armamentarium and open up the possibility of combination therapy in attacking neovascularization through multiple ways.
Ophthalmol Clin North Am
· 2006 Sep · PMID 16935209
·
Publisher ↗
Corticosteroids have been traditionally used for treatment of inflammatory disorders, but recently their angiostatic properties have been explored in neovascular ocular diseases. New corticosteroid compounds designed spe...Corticosteroids have been traditionally used for treatment of inflammatory disorders, but recently their angiostatic properties have been explored in neovascular ocular diseases. New corticosteroid compounds designed specifically to target angiogenesis are being developed, along with novel delivery methods and therapeutic regimes. Corticosteroids are gaining widespread acceptance, particularly in the treatment of retinal diseases, and new advances are being made in understanding their mode of action, optimal administration, and safety. Recent basic and clinical findings about the effectiveness and mechanisms of angiostatic corticosteroids are reviewed in this article.
Ophthalmol Clin North Am
· 2006 Sep · PMID 16935208
·
Publisher ↗
VEGF-A is a critical regulator of ocular angiogenesis and vascular permeability and is involved in the pathogenesis of several ocular diseases involving neovascularization or increased vascular permeability, such as neov...VEGF-A is a critical regulator of ocular angiogenesis and vascular permeability and is involved in the pathogenesis of several ocular diseases involving neovascularization or increased vascular permeability, such as neovascular AMD, diabetic ME, and diabetic retinopathy. Currently available therapies for neovascular AMD, such as laser photocoagulation, PDT with verteporfin, and pegaptanib sodium, slow visual loss but do not improve vision for most patients. In contrast, an emerging anti-VEGF agent, ranibizumab, improved vision in 25% to 34% of treated patients in one clinical trial, rather than slowing visual loss and is the first treatment for neovascular AMD to demonstrate visual improvement in a substantial number of patients. This represents a major advance in the treatment of ocular diseases involving neovascularization or increased vascular permeability and provides hope to patients with these debilitating diseases. Since the submission of this article, ranibizumab was approved by the FDA for the treatment of neovascular AMD.
Ophthalmol Clin North Am
· 2006 Sep · PMID 16935207
·
Publisher ↗
VEGF plays a pivotal role in the neovascularization of the choroid in AMD. Anti-VEGF agents have been developed to target VEGF itself or its receptor signal transduction pathway, and have shown promising results in clini...VEGF plays a pivotal role in the neovascularization of the choroid in AMD. Anti-VEGF agents have been developed to target VEGF itself or its receptor signal transduction pathway, and have shown promising results in clinical trials. The combination of anti-VEGF strategies with established treatment modalities may have additional efficacy. Safe and effective drug-delivery systems are also required for the successful anti-VEGF therapies for AMD and other ocular diseases with CNV.
Ophthalmol Clin North Am
· 2006 Jun · PMID 16701168
·
Publisher ↗
Economic evaluation is an increasingly important component of health and medical care policy making although it continues to be met with some resistance. Many fields of medical care services and public health have extens...Economic evaluation is an increasingly important component of health and medical care policy making although it continues to be met with some resistance. Many fields of medical care services and public health have extensive economic evaluation literatures. In ophthalmology, the literature is less well developed and there is an ongoing discussion of the most appropriate methods. This article outlines different types of economic evaluations providing examples on their potential use in ophthalmic care decision making, reviews three articles in the brief recent literature on the cost-effectiveness of ophthalmic anesthesia and cataract surgery in the United States with a focus on explaining methods that were used, and discusses ways in which research in this area might be moved forward.