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

Proliferation and migration of lens epithelial cells is at the origin of after-cataract, currently the main side effect of cataract surgery. Extracapsular cataract surgery necessitates opening of the anterior lens capsule and removal of the lens fibres before an intraocular lens can be placed in the cleaned capsular bag. The present study was aimed at testing the potential of the lens capsule and the fibres to affect the mitotic activity of the lens epithelial cells in human donor eyes. Pairs of human lenses used in this study were subjected to two different experimental conditions. In the first, only a small anterior capsulorhexis was made. In the other, fibres were separated from the epithelium by gentle hydrodissection, the nucleus was rotated and, either left in the capsular bag or removed by hydroexpression. The specimens were cultured for 48 hr in MEM with 2% serum. Mitotic activity was assessed by immunohistochemistry using the bromodeoxyuridine (BrdU) incorporation technique. Fellow lenses of the same donors were cultured intact as controls. Anterior capsulorhexis showed a small but significant (P < 0.02) increase in the number of BrdU positive nuclei in the equatorial region but not in the wound area. Lenses where fibres were separated from the epithelium showed a large increase in BrdU incorporation in the germinative region, as compared to the intact control lenses (P < 0.01). BrdU incorporation was highest when fibres were removed. Lens capsule integrity and the presence of contacts between fibres and epithelial cells may have a role in the control of the mitotic activity of the lens epithelium. The data recorded here could be useful for understanding lens cell biology and prevention of after-cataract.
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PMID:Separation of fibres from the capsule enhances mitotic activity of human lens epithelium. 909 22

It has been assumed that lens epithelial cells (LECs) existing at the capsulotomy edge have been traumatized through anterior capsulotomy in cataract extraction. In this study, the correlation between traumatized LECs remaining at the anterior capsulotomy edge and epidermal growth factor (EGF) found in the aqueous humor, a cell growth factor though to affect cell morphology, was determined. Anterior lens capsules with adhering LECs were obtained following anterior capsulotomy performed during cataract surgery to first confirm the presence of EGF receptors on LECs, which are needed for EGF to be biologically active. Besides, to identify any EGF receptors on traumatized LECs, I next intentionally traumatized the cells by pressing them with a forceps from the anterior capsular side. It has been found that the LECs containing EGF receptors were always those existing at the edge of the anterior capsular opening and LECs containing EGF receptors existed along the pressed region too. The present results indicate that traumatized LECs along the capsulotomy edge have undergone changes to manifest EGF receptors, thus allowing EGF from the aqueous humor to become more active. The physiological effect of EGF upon these LECs may therefore be one of the causative factors of fibrous opacification of the anterior capsulotomy edge after cataract extraction.
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PMID:Cell biological analysis with respect to cause of fibrous opacification of the anterior capsule after cataract extraction. 978 25

Anterior segment surgeons may treat patients with long-standing media opacities or uncorrected aphakia who have developed sensory strabismus. These patients are at risk for diplopia after surgery to clear the visual axis and restore emmetropia. This report describes 2 patients who regained comfortable single binocular vision without strabismus surgery. Sensory fusion was restored with Fresnel prisms, which were weaned and ultimately discarded as the patients' motor fusion was re-engaged after decades of disuse. Surgeons who restore vision in an eye with manifest sensory strabismus should be aware of this noninvasive, well-tolerated treatment option. Collaboration with an orthoptist or strabismologist may be helpful.
J Cataract Refract Surg 1999 Mar
PMID:Fresnel prism treatment of sensory exotropia with restoration of sensory and motor fusion. 1007 53

Anterior chamber aspirate cultures were done for 66 patients who underwent either an uncomplicated intracapsular cataract extraction, extracapsular cataract extraction with posterior-chamber intraocular lens implantation, or phacoemulsification with posterior-chamber intraocular lens implantation. The aspirate was obtained at the time of wound closure. The aspirates were immediately transferred to the microbiology laboratory where one drop of the aspirate was placed on a glass slide for gram stain, and the remainder was unequally divided and inoculated into blood agar, chocolate agar and thioglycolate broth. The cultures were incubated at 37 degrees C with 5% CO2 and held for 5 days. Of 66 patients 4 (6%), had smear-positive anterior chamber aspirates. None of the aspirates showed any growth on any of the 3 culture media used. None of the eyes in the study developed endophthalmitis. This study concludes that there is no contamination of the anterior chamber by viable bacteria after cataract surgery, irrespective of the mode of intervention.
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PMID:Microbiological profile of anterior chamber aspirates following uncomplicated cataract surgery. 1021 6

Alport syndrome is an inherited disorder of type IV collagen, a major constituent of basement membranes. Eighty-five percent of cases are transmitted through X-linked dominant inheritance, although autosomal dominant and autosomal recessive inheritance has also been reported. Clinical manifestations of Alport syndrome include progressive glomerulopathy, sensorineural deafness, anterior lenticonus, posterior corneal dystrophy, and abnormal retinal pigmentation. Anterior lenticonus may lead to loss of vision because of progressive myopia or cataract formation. We report 2 cases of unusual cataract formation in adolescent boys who had a rupture of the anterior lens capsule. One rupture was spontaneous, and the other was traumatic.
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PMID:Rupture of the anterior lens capsule in Alport syndrome. 1104 Apr 88

A 4-year-old boy with bilateral idiopathic and progressive ectopia lentis had phacoaspiration of the lens and capsular tension ring (CTR) insertion in his left eye. Postoperatively, lens capsule centration remained poor. Single-point scleral fixation of the CTR was performed and centration of the lens capsule achieved. In-the-capsule intraocular lens (IOL) implantation was tried, but excessive IOL manipulation sliced open the capsule at the equator. Anterior vitrectomy and scleral IOL fixation were required. A similar approach was adopted in the right eye with meticulous attention given to gentle maneuvers. The operation was uneventful, with good IOL centration. Three and 11 months after surgery in the right and left eye, respectively, best corrected visual acuity was 20/50 in both eyes. Scleral fixation of the CTR, accompanied by gentle IOL manipulation, is an option to improve IOL centration in patients with severe zonular deficiency.
J Cataract Refract Surg 2000 Apr
PMID:Scleral fixation of a capsular tension ring for severe ectopia lentis. 1077 Dec 39

This study presents a computational model of the growth of the normal human lens and the induction of spoke-like cortical cataract in the aging lens. The anterior lens is modelled as a 2-D disk with a circumferential germinative zone. Lens cortical fibre cells in the same generation cover the surface in three identical 120 deg growth wedge-shaped sectors, with centre cardinal fibres at the 90, 210 and 330 deg meridians. In the foetal lens all primary fibre cells begin to elongate simultaneously. Anterior migration is spatially asynchronous, where the centre fibre begins to move towards the anterior pole first. The fibres at the end of the sector move last in the anterior direction. Fibre elongation advanced at constant speed until the boundary of the sector is reached. Spatio-temporal asynchrony and random fluctuations were increased for the adult lens. The model foetal lens evolved Y-shaped sutures anteriorly, and an inverted Y-shaped posteriorly. Fibre length varied periodically with meridional angle. The adult lens displayed irregular growth. If clusters of germinative cells are caused to opacify the resultant opacities are predominantly spoke-shaped. The model mimics crystalline lens fibre growth to the extent of successfully evolving lens sutures. Fluctuations in lens mass are consistent with an ordered pattern of growth. Lens senescence includes a progressive loss of spatio-temporal synchrony in fibre migration from the germinative zone. Peripheral light focusing by the anterior eye is a possible explanation for the nasal predilection and cuneiform shape of age-related cortical cataract.
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PMID:Temporal and spatial growth patterns in the normal and cataractous human lens. 1097 40

Purpose: To evaluate the association between the vitreous and the refractive error in pseudophakia.Methods: Vitrectomy was performed in 67 eyes of 61 patients who underwent cataract surgery. Vitrectomy was needed for epiretinal membrane in 30 eyes, macular edema in 22 eyes, macular hole in 3 eyes, lamelar macular hole in 2 eyes, macular hole in 3 eyes, lamelar macular hole in 2 eyes, vitreous opacity in 6 eyes, and vitreous hemorrhage in 4 eyes. Refraction was measured before the operation, and 1 month, 3 months, 6 months, and 12 months after operation. Anterior chamber depth was measured in 10 eyes before the operation, and 1 month, 3 months, and 6 months after operation. We evaluated the refractive error after vitrectomy in 49 eyes that had predicted refraction.Results: The mean value of refractive change was -0.3 D 1 month postoperatively, and then gradually became positive. The variation of refraction (6-month postoperative refraction minus preoperative refraction) was negatively correlated with preoperative refraction (P =.0052, R(2) = 0.146). If preoperative refraction was more myopic than -1.5 D, then refraction became positive. If preoperative refraction was not more myopic than -1.5 D, then refraction became negative.Conclusion: About 15% of postoperative refractive error may be associated with the vitreous, but further investigation is required.
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PMID:Refraction and Anterior Chamber Depth Change After Vitrectomy for Pseudophakia. 1134 3

In the past three decades, a great improvement has occurred in microsurgical techniques used in the management of various eye diseases involving retina and vitreous. Advances in instrumentation has made the surgery easier and refined. The instruments used are narrated widely in this article. Various vitreous substitutes have been developed and are required in vitreoretinal surgery. These are gases, silicone oil, perfluorocarbon liquids and fluorosilicone oil. Anterior segment indications for vitreous surgery are: Vitreous loss during cataract surgery, thick after cataracts that can't be managed with Nd: YAG capsulotomy, vitreocorneal touch, updrawn pupils, incarcerated vitreous in the wound causing cystoid macular oedema, malignant glaucoma, penetrating keratoplasty in aphakic patients, congenital cataracts and filtering procedures in aphakic eyes. In posterior segment indications, vitrectomy is useful in penetrating trauma, haemorrhage, retinal deetachment, intra-ocular foreign bodies and infection endophthalmitis Macular surgery involves peeling of epimacular membrane or proliferation, treating vitreomacular traction syndrome, idiopathic macular holes, retinal detachment associated with optic pit, evacuation of submacular haemorrhage and excision of choroidal neovascular membranes. Available options to treat retinal detachments are pneumatic retinopexy, scleral buckling and vitreous surgery. Proliferative vitreoretinopathy remains the important cause of failure and occurs in about 8-10% cases after retinal detachment. Vitreous surgery for ocular trauma, vitrectomy for proliferative diabetic retinopathy, macular hole surgery, submacular surgery are also discussed in detail.
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PMID:Recent developments in vitreoretinal surgery. 1139 74

The authors present results of 32 operations with capsular tension ring performed in eyes with zonular dehiscence. There were 14 women (50%) and 14 men (50%), altogether 28 patients (32 eyes). Mean patient age was 47.1 years (range 22-89 years). The reason for zonular weakness was trauma in 15 eyes (46.9%), Marfan's syndrome in 8 eyes (25.0%), pseudoexfoliation syndrome in 6 eyes (18.7%) and high myopia in 3 eyes (9.4%). Anterior vitrectomy was done if the vitreous appeared in the anterior chamber. Early postoperative complications were fibrinoid reaction in 2 eyes (6.3%), intraocular pressure elevation in 5 eyes (15.6%), hyphaema in 2 eyes (6.3%). Best corrected visual acuity was 0.5 or better in 18 eyes (56.3%) on the first postoperative day and in 17 eyes (53.1%) at the time of the last examination. Our results have shown the high efficiency of the capsular tension ring in managing zonular problems during cataract surgery.
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PMID:[Results of 32 cataract operations using the capsular ring]. 1143 90


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