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Query: UMLS:C0086543 (cataract)
 29,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Since 1963, the Choyce Mark VIII lens, a quadrupedal, anterior chamber implant, has proved satisfactory following conventional intracapsular surgery in eyes of normal size, but less successful after primary extracapsular procedures and in small eyes. Reducing some of its dimensions by as much as 30% enables the surgeon to treat a much wider range of cataract problems through a smaller incision. The reduced-size version is known as the Choyce Mark IX anterior chamber implant. The quadrupedal principle has been preserved.
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PMID:The evolution of the anterior chamber implant up to, and including, the Choyce Mark IX. 53 May 73

We reviewed 70 cases that had undergone secondary lens implantation. The lenses used included 34 Medallion and 36 Choyce Mark VIII lenses. A 20/40 or better vision was present in 74.3% of the cases before implantation, and could be achieved postoperatively in 95.7% of the cases. Corneal changes, i.e. endothelial corneal dystrophy and induced astigmatism, were not noted in cases where Choyce Mark VIII lenses were used. Cystoid macular edema occurred in three cases where surgery followed an intracapsular cataract extraction (5.3%).
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PMID:Secondary lens implantation in aphakia: visual results and complications. 74 9

The author's experiences with the Choyce Mark VIII implant have been statistically reviewed. The results reveal no significant increase in complications over standard cataract extraction without implantation. Secondary implantation is compared with primary implantation. The results seem to support the author's position that secondary implantation with the Choyce lens carries a 3-5% incidence of complications which must be weighed against the patient's need for further rehabilitation. The importance of fixation in implantation has been reviewed from an historical standpoint to support the conclusion that the Choyce lens owes much of its superior results to its ideal fixation and lack of pseudophakodonesis.
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PMID:Results of primary and secondary implants using Choyce Mark VIII lenses. 90 75

We have compared long-term intraocular pressure control in patients with open angle glaucoma, cupping and atrophy of the optic nerve head and visual field loss as well as cataract after: trabeculectomy posterior to the scleral spur and cataract extraction without implantation in 108 patients. guarded posterior lip sclerectomy, cataract extraction and Mark VIII or Mark IX anterior chamber implantation in 28 patients. argon laser trabeculoplasty followed by lens extraction and implantation in 27 patients. Approximately 75 per cent of patients achieve intraocular pressures of 18 mm Hg or less without medication after (a), and approximately 40 per cent of patients achieve similar control without medication after (b). Approximately 25 per cent of these glaucoma patients have intraocular pressure levels of less than or equal to 18 mm Hg on topical medication three months after ALT, and none achieve this control without medication. Cataract surgery with anterior or posterior chamber implantation caused loss of topical control in four of the seven patients benefiting from ALT. These data imply that combined surgery with or without implantation produces better and more significant intraocular pressure control than the presently utilized techniques of ALT subsequently followed by lens extraction and implantation.
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PMID:Laser trabeculoplasty and cataract surgery. 385 41

The validity and reproducibility with which six classifiers [one experienced (L.T.C.), and five novices (W.G., F.G., W.W., J.W. and O.W.)] used the CCRG cataract classification system was assessed. The validity of index classifications was assessed by computing sensitivities and pairwise interclass correlations between experienced and novice classifiers using the former's classification as the standard. The number of unordered combinations of terms in the CCRG's classification was reduced by combining cortical terms according to the CCRG's accepted system of staged simplification. The number of combinations of terms at each stage is as follows: Stage I (greater than 1000); II (127); III (63); IV (15); V (7); VI and VII (3) and VIII (2). Excellent agreement was obtained between the experienced and novice classifiers for Stages VII and VIII of the classification, good agreement for Stages V and VI and poor agreement for Stages IV, III and II (sensitivities of 97, 96, 72, 59, 40, 24 and 20% respectively). Good agreement was also achieved for the classifications of single lenticular regions, except for subcapsular regions. The intra- and interobserver reproducibility was assessed by computing the Kappa statistic to (1) compare classifications between novice observers and (2) compare repeat classifications made by the same observer by viewing the same cataract once on each of three different days. The novice classifiers had excellent intraobserver reproducibility for Stages VII and VIII (Kappas of 0.87 and 0.97 respectively), good reproducibility for Stages IV, V and VI (Kappas of 0.53, 0.62 and 0.62, respectively) and marginal reproducibility for stages II and III (Kappas of 0.39 and 0.40, respectively). The intraobserver reproducibility of the experienced classifier was superior to the others for virtually all characteristics with excellent reproducibility for Stages IV, V, VI, VII and VIII with Kappas of 0.79, 0.90, 1.0, 1.0 and 1.0, respectively and good reproducibility for Stages II and III (Kappas of 0.55 and 0.64, respectively). These results indicate that the simplified CCRG cataract classification system (Stages IV-VIII) passes the minimum standards for reproducibility. The performance of the experienced classifier far exceeds the minimum standards and indicates the feasibility of improving classifier performance with training and practice.
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PMID:Validity and reproducibility of the Cooperative Cataract Research Group (CCRG) cataract classification system. 397 55

Eighteen rhesus monkeys underwent lens implantation with Choyce Mark VIII, Binkhorst iridocapsular, or Shearing posterior chamber lenses. They were sacrificed 4-28 months postoperative. The eyes were compared clinically and histologically. Controls included unoperated eyes and eyes with lens extraction without implantation. Several histologic findings pertained equally to cataract extraction with or without lens implantation. Late opacification of the posterior capsule was caused by migrations and fibrous metaplasia of the lens epithelial cells. These cells appeared to undergo such metaplasia only when exposed directly to aqueous, never when they were in firm apposition to another tissue such as another layer of capsular epithelium, lens cortex, or iris. All implants were well tolerated clinically. Histologically the eyes with Binkhorst lenses showed a tendency to focal loss of iris pigment epithelium and some pigmented macrophages in the iris stroma an trabecular mesh. The Choyce lenses frequently displayed marked displacement and thinning of the iris root, and occasionally showed a few chronic inflammatory cells and thin fibrous encapsulation around the implant feet. The Shearing lenses had no effect on the adjacent ciliary body when the loops were well seated in the lens capsule, but when a loop was anterior to the capsule, it eroded into the ciliary body. The loops developed a thin fibrous capsule within the ciliary body with very little chronic inflammatory reaction. The long-term effect of such loops lying in the ciliary body is undetermined, however. At present it is recommended that, if such a lens is implanted, every effort be made to ensure both loops lie in the capsular envelope. On the basis of this study, it is also recommended that in removing such a lens, one must assume that a loop might lie embedded in the ciliary body and cut the lens free from the loops before removing it.
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PMID:Extracapsular cataract extraction and pseudophakos implantation in primates: a clinico-pathologic study. 723 66

Eighteen Rhesus monkeys underwent lens implantation with Choyce Mark VIII, Binkhorst iridocapsular, and Shearing posterior chamber lenses. They were sacrificed 4 to 28 months following surgery. The eyes were compared clinically and histologically. Controls included unoperated eyes and eyes with lens extraction without implantation. Several histologic findings pertained equally to cataract extraction with or without lens implantation. Late opacification of the posterior capsule was caused by migration and fibrous metaplasia of the lens epithelial cells. These cells appeared to undergo such metaplasia only when exposed directly to aqueous, never when they were in firm apposition to another tissue such as another layer of capsular epithelium, lens cortex, or iris. Also strong fibrous posterior synechiae between the iris and lens remnants occurred only where the anterior lens capsule was missing. All implants were well tolerated clinically. Histologically they showed remarkably little inflammation. The eyes with Binkhorst lenses had a mild tendency to focal loss of iris pigment epithelium and some showed pigmented macrophages in the iris stroma and trabecular mesh. The Choyce lenses frequently displayed marked displacement and thinning of the iris root, and occasionally showed a few chronic inflammatory cells and thin fibrous encapsulation around the implant feet. The Shearing lenses had no effect on the adjacent ciliary body when the loops were well seated in the lens capsule, but when a loop was anterior to the capsule, it eroded into the ciliary body. The loops developed a thin fibrous capsule within the ciliary body with very little chronic inflammatory reaction, but the long term effect of such loops lying in the ciliary body is undetermined. At present it is recommended that, if such a lens is implanted, every effort be made to ensure both loops lie in the capsular envelope. On the basis of this study, it is also recommended that in removing such a lens, one must assume that a loop might lie embedded in the ciliary body and cut the lens free from the loops before removing it.
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PMID:Extracapsular cataract extraction and pseudophakos implantation in primates: a clinico-pathologic study. 725 72

Lens capsules become fibrotic after the extraction of a cataract. To understand this phenomenon, we evaluated the immunolocalization of prolyl 4-hydroxylase (an enzyme involved in procollagen hydroxylation), and extracellular matrix components and cytoskeletal components in a normal human lens capsule and in others with intraocular lenses. Lens capsules containing intraocular lenses were removed from a patient with proliferative vitreoretinopathy and three with proliferative diabetic retinopathy during vitreous surgery. Two circular sections of the anterior capsules with lens epithelial cells were obtained by anterior capsulotomy during cataract surgery. In addition, a lens capsular bag was obtained immediately after phacoemulsification. The lens capsules were processed for light microscopic immunohistochemical detection of the alpha and beta subunits of prolyl 4-hydroxylase, extracellular matrix components (including collagen types, laminin and cellular fibronectin) or cytoskeletal components (such as cytokeratin, vimentin and alpha-smooth muscle actin). Monolayer lens epithelial cells were seen on the inner surface of the normal anterior capsules. Each intraocular lens was found to be fixed in the capsular bag. Light microscopic immunohistochemistry showed that these proliferating cells expressed vimentin and alpha-smooth muscle actin; in contrast, quiescent lens epithelial cells did not stain for alpha-smooth muscle actin. Marked immunostaining for subunits of prolyl 4-hydroxylase was detected in lens epithelial cells proliferating on the capsules, while no or only faint prolyl 4-hydroxylase immunoreactivity was detected in quiescent lens epithelial cells immediately after phacoemulsification. Collagen types I, III and VI and cellular fibronectin were observed diffusely in accumulated connective tissue on a capsule with an intraocular lens. Type IV collagen immunoreactivity was seen both in the capsules and in the connective tissue accumulation on the capsules. Collagen V and laminin were detected in association with cellular proliferation. Collagen VII and VIII and laminin 5 were not seen. We concluded that during wound healing of the lens capsule after cataract extraction, the lens epithelial cells that proliferate on the inner surface of the capsule transform it into a myofibroblastic phenotype, expressing prolyl 4-hydroxylase and alpha-smooth muscle actin. These proliferating cells are involved in the production of collagen on the lens capsule. This results in a postoperative fibrotic process and contraction of the lens capsule.
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PMID:Immunolocalization of prolyl 4-hydroxylase subunits, alpha-smooth muscle actin, and extracellular matrix components in human lens capsules with lens implants. 953 56

Anticataract activity of Ambroxol, Spirulina and Vitamin E was examined using the naphthalene cataract model. Adult female albino rats of Wistar strain weighing between 180 and 220 grams were taken and divided into eight groups. Group I received light liquid paraffin 5 ml/kg/ day p.o. for 6 weeks. Group II received naphthalene solution 0.5 gm/kg/ day p.o. for first three days and 1 gm/kg/day p.o. thereafter for six weeks. Group III received Ambroxol suspension in 0.5% carboxy methyl cellulose (CMC) at the dose of 100 mg/kg/day p.o. alongwith naphthalene. Group IV received Spirulina in distilled water at the dose of 1500 mg/kg/ day p.o. alongwith naphthalene. Group V received Vitamin E emulsion at the dose of 50 mg/kg/day p.o. alongwith naphthalene. Group VI received Ambroxol alone at the dose of 100 mg/kg/day p.o. Group VII received Spirulina alone at the dose of 1500 mg/kg/day p.o. Group VIII received vitamin E alone at the dose of 50 mg/kg/day p.o. Lens glutathione, soluble protein and water content profiles revealed the preventive role of Ambroxol, Spirulina and Vitamin E in naphthalene-induced cataract in female rats.
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PMID:Effect of ambroxol, spirulina and vitamin-E in naphthalene induced cataract in female rats. 1588 59

We analyzed an enucleated eye that was blind and painful from a 66-year-old patient implanted with a Tennant modification of the Choyce Mark VIII anterior chamber intraocular lens (IOL) as a secondary procedure in 1978. The eye developed glaucoma, with implantation of an Ahmed valve in 2006. Gross and light microscopic analyses showed corneal decompensation and vascularization, peripheral anterior and posterior synechiae, iris thinning, significant changes in the iris pigmented layer, fibrous tissue on the anterior surface of the iris, and Soemmerring ring formation in the periphery of capsular bag remnants. In addition, there was severe attenuation of the nerve fiber layer and extensive cupping of the optic disc. The IOL surface was overall smooth and regular, without warping of the footplates, and was partially covered by clumps of various cell elements, including giant cells intermixed with pigment. This study represents the longest clinicopathologic correlation report on this IOL.
J Cataract Refract Surg 2012 Feb
PMID:Long-term pathologic follow-up of obsolete design: Choyce Mark VIII anterior chamber intraocular lens. 2211 90


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