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Biomedical subjects

A E Maumenee

Publications and source records attributed to A E Maumenee.

At least 55 records · Page 3Linked to original sources
PubMed1985

Tissue toxicity of laser-damaged intraocular lens implants.

Because of close proximity to the posterior capsule, the posterior chamber intraocular lens is frequently damaged when capsulotomy is performed using the Nd:YAG laser. Damage to the optic or haptics of an intraocular lens may release substances potentially toxic to intraocular tissues. We found that injection molded intraocular lenses experimentally damaged using multiple YAG laser burst at energy levels of 10 mJ or greater released compounds which caused cell death to cultures of human conjunctival epithelial cells, retinal pigment epithelial cells, choroidal cells, and retinoblastoma cells. No cytotoxic effect was seen at energy levels of 2 and 5 mJ.

Cataract Extraction↗
PubMed1985

Ultrastructural studies of cornea, iris and lens in a case of siderosis bulbi.

Transmission electron microscopy studies of cornea, iris and lens from a case of ocular siderosis due to a retained intraocular foreign body (IOFB) and vitreous hemorrhage are presented. We observed widespread degeneration of lens epithelium, iris stromal cells and iris pigment epithelium associated with intra- and extracellular siderosomes. A direct relationship was found between the degree of cell degeneration and the number of intracellular siderosomes in lens epithelium. This is contrary to findings in other siderotic tissues which show intracellular iron deposition to be associated with increased ability to detoxify iron. The cornea showed siderosomes only within keratocytes, and there was no evidence of a relationship between siderosome accumulation and cell degeneration. The literature on ultrastructural studies of ocular siderosis is reviewed and the current theory of the mechanism of chronic iron toxicity is discussed.

Adult↗
PubMed1984

Cystoid macular edema in pseudophakia.

Cystoid macular edema after cataract surgery, with or without intraocular lens implantation, has been reported to develop in more than 50% of patients as detected by fluorescein angiography. It is associated with reduced visual acuity in up to 8% of cases. Analysis of ongoing clinical trials at the Wilmer Institute indicates that clinically significant cystoid macular edema develops in a lower percentage of cases (2% total incidence and 0.3% persistent cystoid macular edema) if the intraocular lens implantation was uncomplicated. The factors associated with cystoid macular edema and the importance of considering clinically significant rather than just fluorescein-proven cystoid macular edema are discussed. Results of intraocular lens studies reported to the Federal Drug Administration are updated, and results of an ongoing study of prostaglandin inhibitors at the Wilmer Institute are reported.

Aged↗
PubMed1984

Possible mechanisms for the loss of goblet cells in mucin-deficient disorders.

By studying the pathological changes in human conjunctival flaps and the conjunctival transdifferentiation in rabbits, we have identified and correlated two pathological processes with the loss of goblet cells: (1) loss of vascularization, and (2) intense inflammation. Loss of vascularization may be correlated with the loss of goblet cells in the chronic cicatricial stage of various mucin-deficient disorders, whereas inflammation may be responsible for their absence in the acute inflammatory stage. The exact interrelationship between these two processes remains unknown. The loss of goblet cells appears to be an early sign of a spectrum of squamous metaplasia, an abnormality of epithelial differentiation. We therefore speculate that loss of vascularization and intense inflammation may have an important effect on epithelial differentiation.

Adult↗
PubMed1984

A new posterior chamber intraocular lens formula for axial myopes.

The accuracy of prediction of postoperative refractive error was evaluated in 175 patients with extracapsular cataract extraction and a Shearing-style posterior chamber intraocular lens. The Binkhorst, Colenbrander - Hoffer and SRK formulas were all less accurate in patients with an axial length greater than or equal to 24.5 mm. The standard error of the estimates of the Binkhorst formula was 1.2 diopters, the Colenbrander - Hoffer formula 1.18 diopters and the SRK formula 0.90 diopters. A new intraocular-lens formula for axial myopes was derived by polynomial regression analysis with a standard error of the estimate of 0.85 diopters. This new formula was accurate within 1 diopter in 79% of axial myopes compared to 71% for the SRK , 66% for the Colenbrander - Hoffer and 64% for the Binkhorst formulas. Regression analysis of a surgeon's own patient data can further improve the accuracy of prediction of the post-operative refraction.

Cataract Extraction↗
PubMed1984

Posterior chamber intraocular lenses at the Wilmer Institute: a comparative analysis of complications and visual results.

Intraocular lens (IOL) implantation is now accepted as the most effective means of aphakic correction in selected patients undergoing cataract surgery. In terms of final rehabilitation, however, complications such as corneal oedema, retinal detachment, and cystoid macular oedema remain problematic. Results of prospective concurrent trials of IOL implantation performed at the Wilmer Institute are presented, with particular reference to the posterior chamber intraocular lens and with specific emphasis on postoperative complications.

Aged↗
PubMed1983

Extended-wear soft contact lenses for aphakic correction.

Evaluation of an extended-wear perfilcon A soft contact lens (Permalens) in 299 eyes of 244 patients showed that 266 eyes (89%) were successfully fitted and wore the lenses without important complications (mean follow-up, 23 months; range, four to 48 months). Use of the lens in 33 eyes was discontinued because of transient lens-related problems. "Overcorrected" acuity of 6/12 (20/40) or better (with spectacles plus the contact lens) was achieved in all patients who were without vitreous, retinal, or optic nerve disease. Seventy-six percent of patients could wear the lens for longer than one-month intervals, and 30% removed the lens at four- to six-month intervals. There were no cases of infectious corneal ulcers or scarring or permanent visual loss. Our more limited experience with lidofilcon B lenses (Sauflon PW) (24 eyes) and the silicone lenses (Silsoft) (25 eyes) also showed beneficial results.

Aged↗
PubMed1983

Aphakic extended-wear contact lenses after penetrating keratoplasty.

Fifteen aphakic eyes in 15 selected patients who underwent penetrating keratoplasty were successfully fitted with extended-wear contact lenses three to 42 months postoperatively. After an average follow-up of 17 months, there was no graft edema, no microbial corneal ulcers, and no episode of graft rejection. Three eyes developed minor (1 to 2 mm) graft neovascularization; the neovascularization was stable and did not require discontinuation of the contact lenses. Fourteen of the 15 patients had postoperative visual acuities of 20/70 or better; the one patient whose visual acuity was worse than 20/70 had a clear graft but also had senile macular degeneration.

Aged↗
PubMed1983

Neodymium-YAG laser for posterior capsulotomy.

We used the neodymium-YAG laser to perform discission of the posterior capsule in 49 eyes of 47 patients who had undergone previous extracapsular cataract extraction. The visual results were encouraging, with an improvement in visual acuity of one or more Snellen lines in 45 eyes and an improvement of three or more Snellen lines in 33 eyes. The complications included increases in intraocular pressure in 28 eyes. Intraocular pressures between 21 and 40 mm Hg were detected in 21 eyes and exceeded 41 mm Hg in another seven. In 14 of the 16 eyes in which intraocular pressure increased to more than 30 mm Hg, the maximum intraocular pressure was detectable within three hours after treatment. Other complications included damage to the intraocular lens in 12 of 30 eyes with implants and rupture of the anterior hyaloid face with forward displacement of vitreous into the anterior chamber in six of 19 eyes without implants. One of these eyes later developed a rhegmatogenous retinal detachment. A transient laser-induced hemorrhage occurred in one eye.

Aqueous Humor↗
PubMed1983

Pathology of intraocular lenses in 33 eyes examined postmortem.

Thirty-three pseudophakic eyes from 29 patients were examined postmortem. Clinically, 25 of the eyes had had visual acuities of 20/50 or better. In general the intraocular lenses (IOLs) were quite well tolerated. Iris atrophy and erosion were prominent features of eyes containing an anterior chamber, iris fixation, or iridocapsular lens. Angle recession and ciliary-body erosion were found in some eyes with anterior chamber lenses. Ciliary-body erosion by haptics was seen with posterior chamber lenses. Pupillary membranes were present in eight eyes. Granulomatous reaction to IOL material was present in 13 eyes. Usually this was localized to the site of the lens haptic, and was consistent with good visual acuity. One eye with a posterior chamber lens had been successfully treated for Staphylococcus epidermidis endophthalmitis after capsulotomy, shortly before death. Central corneal endothelial cell loss seemed to be of similar amount for the anterior chamber, iris fixation, and iridocapsular lenses, but was less severe in eyes with posterior chamber lenses. Cystoid macular edema was present in five eyes, retinal phlebitis in two eyes, and retinal detachments in four eyes.

Aged↗
PubMed1983

Update of the intraocular lens. Experience at the Wilmer Institute.

A series of 795 primary intraocular lens (IOL) implantations performed at the Wilmer Institute during the past 6 years by two surgeons were reviewed. Progressive corneal endothelial-cell loss and an increased rate of late-onset corneal edema were detected in the group with the Morcher (European) four-loop iris-clip Binkhorst IOLs. Clinically significant cystoid macular edema was more frequent in eyes with the American four-loop Binkhorst lens, presumably due to chronic iritis caused by contaminants on the IOLs. Our short-term results with the American Shearing-type IOLs implanted at the time of extracapsular cataract extraction are encouraging, with 98% of the cases achieving 20/40 vision or better, excluding those with known macular degeneration or amblyopia. A continued cautious approach to IOL implantation is recommended.

Aged↗
PubMed1983

Intraocular lenses: experience at The Wilmer Institute.

Nine hundred and thirty-eight consecutive primary intraocular lens (IOL) implant cases performed at The Wilmer Institute during the past six years by two surgeons were reviewed. Progressive corneal endothelial cell loss and an increased rate of late-onset corneal oedema were detected in the group with the Morcher (European) four-loop iris-clip Binkhorst IOLs. A higher rate of clinically-significant cystoid macular oedema developed in eyes with the American-manufactured four-loop Binkhorst lens, presumably from chronic iritis caused by contaminants on the IOLs. Our short-term results with the American-manufactured Shearing-type IOLs implanted at the time of extracapsular cataract extraction are encouraging, with 96% of cases achieving 20/40 vision or better, excluding those with known macular degeneration or amblyopia. Analysis of data submitted to the United States Food and Drug Administration (FDA) indicates that most of the four classes of intraocular lenses (anterior chamber, pupillary-supported, iridocapsular, and posterior chamber) are safe and effective at one-year follow-up. During the past three years there has been a gradual shift of preference in the type of IOLs being implanted--away from pupillary-supported and iridocapsular IOLs and, in part, from anterior chamber IOLs, to posterior chamber IOLs. A continued conservative approach to IOL implantation is recommended.

Aged↗
PubMed1982

Birdshot retinochoroidopathy associated with HLA-A29 antigen and immune responsiveness to retinal S-antigen.

Antigen HLA-A29 was present in 16 of 20 patients (80%) with birdshot retinochoroidopathy, but only in 31 of 418 controls (7.4%) (P less than .0001). The relative risk for this disease in persons possessing HLA-A29 antigen was 49.9, one of the highest reported. Of the 20 patients, 13 were also tested for evidence of an in vitro mitotic immune response to purified retinal S-antigen. Of these, 12 (92.3%) responded to the purified preparation, whereas one responded only to a crude retinal homogenate. The histopathologic and clinical findings in an eye from one of the responders to the S-antigen were similar to those in the disease induced in monkeys with the S-antigen. Our findings suggested that birdshot retinochoroidopathy has a genetic predisposition and that retinal autoimmunity, resulting from the S-antigen or other retinal antigens, plays a role in the manifestation of this disease.

Adult↗
PubMed1982

Clear-cornea cataract extraction in eyes with functioning filtering blebs.

In 22 glaucomatous eyes with functioning filtering blebs and adequately controlled intraocular pressures (less than or equal to 22 mm Hg) that underwent clear-cornea cataract extraction, the intraocular pressure remained controlled in 20 (91%). Seven of the 21 eyes, however, required an increased dosage of antiglaucoma drugs. Sixteen eyes had final visual acuities between 6/6 and 6/9 (20/20 and 20/30) and only four eyes had final visual acuities worse than 6/60 (20/200). The only intraoperative complication was a ruptured lens capsule. Postoperative bullous keratopathy developed in two eyes, both of which had had corneal edema postoperatively. A third eye, which had undergone filtering surgery 17 years earlier, had vitreous incarceration after the sutures were removed.

Aged↗