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

Anterior polar cataracts (APC) are a relatively rare but well-documented form of congenital cataract. Occasionally, these white disc-shaped opacities protrude towards the anterior chamber with an inverse cone-like morphology and are known as anterior pyramidal cataracts. These represent three to four per cent of all types of congenital cataracts. APCs portray a dominant mode of inheritance and generally do not progress over time. Due to their small size, APCs generally have little effect on vision and are simply monitored clinically. Photodocumentation of pyramidal cataracts has traditionally shown biomicroscopic views of the opacities. In addition to a review of APC, this report describes how a gonioscope offers a unique observational advantage in viewing an anterior pyramidal cataract.
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PMID:Unique advantage of gonioscopy for viewing an anterior pyramidal cataract. 1236 62

A 52-year-old man had loss of vision and black discoloration of the lids of the right eye after a retrobulbar injection of 3 mL lidocaine hydrochloride 2% (Xylocaine). Examination of the right eye revealed no light perception with extensive necrosis of the lids. Anterior segment examination revealed conjunctival pallor, corneal edema, and necrosis of the sclera. This is a previously unreported complication of retrobulbar anesthesia comprising ophthalmic artery occlusion with scleral melt, ocular ischemia, and eyelid necrosis.
J Cataract Refract Surg 2003 Apr
PMID:Necrosis of the eyelids and sclera after retrobulbar anesthesia. 1268 60

Neuro-ophthalmologic complications from cataract surgery are uncommon and include central nervous system toxicity, binocular diplopia, traumatic optic neuropathy and ischemic optic neuropathy. Retrobulbar blocks may be accidentally injected into the subarachnoid space with diffusion to the brainstem. This leads to cardiovascular, respiratory, and mental status compromise. Most patients have complete recovery with adequate support. Post-operative, binocular diplopia may occur secondary to anisometropia or previously unrecognized misalignment. Periocular injection may cause paresis or fibrosis of extraocular muscles. Anterior or posterior ischemic optic neuropathy can occur in the first 6 weeks after cataract surgery with or without periocular injection. The risk to the other eye is high with subsequent contralateral cataract extraction. Post-operative vision loss associated with direct traumatic needle injury is recognized immediately. Therefore, an orbital MRI may be warranted for a patient with an optic neuropathy in the first 24 hours after cataract surgery using periocular anesthesia. If evidence of needle injury is present on neuroimaging, a trial of steroids should be considered.
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PMID:Neuro-ophthalmologic complications of cataract surgery. 1275 44

Anterior subcapsular cataracts cause a serious loss of vision and are normally associated with ocular trauma, inflammation or clinical skin conditions. They appear to be accompanied by epithelial cell growth and transdifferentiation where unscheduled production of a number of proteins, including alpha smooth muscle actin (alpha-sma), occurs. Clinical studies have also revealed an up-regulation of the TGFbeta signalling pathway in such cataracts. The present study, using phase contrast and immunofluorescent techniques, was undertaken to investigate the extent of alpha-sma expression in traumatic cataracts, in capsulorhexis specimens obtained during cataract surgery and in aged human lenses from donor eyes. The donor lenses were also exposed to trauma or TGFbeta in culture to observe their relative contribution to alpha-sma production. Dense anterior subcapsular cataracts were relatively rare (<1%), but all showed a pronounced up-regulation of alpha-sma, which was located both in anterior cells of normal appearance and in nucleated fibroblastic cells lying beneath the anterior epithelium. Surprisingly, more than 50% of capsulorhexis specimens from mature cataracts showed expression of alpha-sma, although to a limited extent. Alpha-sma was not expressed in any of the clear donor lenses and culture for 8 days in EMEM did not induce expression. Interestingly, unlike their young animal counterparts, human lenses failed to show the presence of alpha-sma when exposed to 10 ng ml(-1) TGFbeta. However, after culture, lenses with pre-existing cortical opacities did express alpha-sma, as did clear lenses subjected to injury or trauma. It appears that the greater the stress, the greater is the expression of alpha-sma. Cataract, and especially cortical cataract, should therefore be seen as associated with stress-induced signalling pathways in the lens that lead to the transdifferentiation of the anterior epithelial cells.
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PMID:Epithelial transdifferentiation and cataract in the human lens. 1290 66

A 55-year-old woman had bilateral laser in situ keratomileusis (LASIK). An epithelial defect was observed in the left eye after the flap was cut. Postoperatively, the patient developed recurrent corneal erosion in the left eye related to the traumatic epithelial defect sustained during LASIK. The erosion led to secondary diffuse lamellar keratitis (DLK). Anterior stromal puncture was required to treat the erosion after conventional treatment failed. The secondary DLK resolved quickly after the erosion healed, without the need for topical corticosteroids. Anterior stromal puncture may be a useful treatment for recurrent corneal erosions that do not respond to conventional therapy.
J Cataract Refract Surg 2004 Feb
PMID:Anterior stromal puncture for recurrent corneal erosion after laser in situ keratomileusis. 1572 75

Anterior segment optical coherence tomography is a new method to explore the anterior chamber. The target can be focused and defocused with positive or negative lenses to reproduce the conditions of natural accommodation. We studied accommodation in an albino patient because the absence of pigment allows the infrared beam to penetrate the iris and explore the modifications of the ciliary body and the crystalline lens during natural accommodation in a human subject.
J Cataract Refract Surg 2004 Mar
PMID:Anterior chamber optical coherence tomography study of human natural accommodation in a 19-year-old albino. 1576 26

The objective of this study was to determine the frequency of intraoperative contamination of the anterior chamber with viable microorganisms during cataract phacoemulsification and intraocular lens implantation, and to evaluate the relationship of contaminant microorganisms to patients' extraocular and nasal cavity floras. Also, the impact of various aspects of the patient history and phacoemulsification procedure on the incidence of positive postoperative anterior chamber cultures was investigated. Twenty-two eyes from 13 dogs presented for elective cataract phacoemulsification and intraocular lens implantation were studied. Preoperatively, microbiologic samples of the conjunctiva, eyelid margins, nares, and rostral nasal cavity were collected. Postoperatively, anterior chamber fluid was aspirated. Samples were submitted for aerobic/anaerobic bacteriologic culture and antimicrobial susceptibility, Mycoplasma culture, and fungal culture. Anterior chamber aspirates collected at the conclusion of surgery were culture positive for at least one organism in 22.7% of eyes. Three aerobic bacteria and three fungi were isolated from the anterior chamber aspirates. Two fungi and one bacterium isolated from the anterior chamber were typed identically, and the bacterium had a similar antibiogram to organisms recovered from the patient's conjunctiva and eyelid margin. No statistically significant difference in contamination frequency was found for the investigated patient and surgical variables. We conclude that intraoperative contamination of the anterior chamber with viable bacterial and fungal organisms is a common occurrence in canine patients undergoing cataract phacoemulsification and intraocular lens implantation, and the external ocular flora is a likely source of some of these contaminating microorganisms. This contamination is independent of the patient and surgical variables investigated.
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PMID:Microbial contamination of the anterior chamber during cataract phacoemulsification and intraocular lens implantation in dogs. 1531 Feb 92

Bilateral congenital cataract is the most common cause of treatable childhood blindness. Nuclear cataract is usually present at birth and is nonprogressive, whereas lamellar cataract usually develops later and is progressive. Surgery must be performed promptly in cases with dense congenital cataract; if nystagmus has developed, the amblyopia is irreversible. A treatment regimen based on surgery within 2 months of birth combined with prompt optical correction of the aphakia and aggressive occlusion therapy with frequent follow-up has been successful in unilateral and bilateral cases. Both anterior and posterior capsulorhexes are performed in most children. Intraocular lens implantation can be performed safely in children older than 1 year. Anterior dry vitrectomy is recommended in preschool children to avoid after-cataract. Opacification of the visual axis is the most common complication of cataract surgery in children. Secondary glaucoma is the most sight-threatening complication and is common if surgery is performed early. Life-long follow-up is essential in these cases.
J Cataract Refract Surg 2005 Apr
PMID:Cataracts in children. 1589 63

A 69-year-old man who had pseudoexfoliation and significant nuclear cataract underwent cataract surgery in his right eye. At the beginning of the phacoemulsification, inferior zonulolysis was observed and a capsular tension ring was implanted. Anterior vitrectomy was also performed because of vitreous in the anterior chamber at the end of surgery. A tear in the posterior capsule could not be identified. Three days after surgery, the capsular tension ring was observed partially in the anterior vitreous. A 3-port pars plana vitrectomy was performed and the ring was removed. Three weeks later, the eye developed retinal detachment and was successfully repaired. Retinal complications can develop if the capsular tension ring moves into the vitreous.
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PMID:Posteriorly dislocated capsular tension ring. 1623 42

Intraocular lens power (IOL) calculation for cataract surgery has been shown to be inaccurate after photorefractive keratectomy (PRK), laser-assisted subepithelial keratectomy (LASEK) and laser in situ keratomileusis (LASIK). Many techniques exist to calculate corneal power with varying results and require the clinician to be aware of the pitfalls of IOL power calculation in post-refractive eyes. The AS biometry method proposed here is a simple method which does not rely on the calculation of corneal power. This new method is compared to the current gold standard the clinical history method (CHM). Twenty-nine eyes of 15 patients had routine biometry prior to LASIK, LASEK or PRK. The range of pre-operative spherical equivalent refractive error was -5.37 to +4.00 diopters. The post-operative refraction was measured at 3-6 months. The IOL power calculation was calculated using the AS biometry method and the CHM. The two methods were compared using the Student's paired t-test and the Bland Altman technique. There was no statistical difference between the AS biometry method and the CHM. The paired Student's t-test comparing the AS biometry method and the CHM showed no statistical difference, t=0.33 with a p-value of 0.75, at a 95% confidence interval. The authors conclude that the AS biometry technique is as accurate as the CHM. The former is a simpler method which avoids many of the pitfalls and confounding factors involved in IOL power calculation following corneal excimer laser surgery. However, like the CHM it requires measurements prior to laser surgery.
Cont Lens Anterior Eye 2006 May
PMID:The AS biometry technique--a novel technique to aid accurate intraocular lens power calculation after corneal laser refractive surgery. 1660 Jun 67


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