Anxiety, conflict, and perception of everyday decisions.
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Adult↗
Biomedical subjects
S Melamed
Publications and source records attributed to S Melamed.
The management of non-insulin-dependent mellitus.
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Diabetes Mellitus, Type 2↗
Anterior and posterior axial lens displacement and human aqueous outflow facility.
We studied the effect of anterior and posterior axial crystalline lens displacement (and thereby ciliary tone) on the aqueous humor outflow facility in enucleated human eyes. After attaching a reversible footplate plunger to the anterior lens capsule with cyanoacrylate, the lens was placed in one of three positions: "neutral baseline," posterior displacement (2.5 mm), or anterior displacement (2.0 mm). In seven pairs of eyes, the mean "neutral baseline" was not statistically different from the control eye, but anterior lens displacement decreased outflow facility "C" by 0.14 (36%) (P less than 0.0001), and posterior displacement increased "C" by 0.18 (50%) (P less than 0.01). Anterior or posterior lens displacement after complete ciliary body detachment produced no effect on outflow facility in two pairs. Histologic correlation studies demonstrated narrowing of the intertrabecular spaces and Schlemm's canal in the eyes fixed in anterior lens displacement, and widening of the same structures in the eyes fixed in posterior lens displacement. The lens-zonular-ciliotrabecular force vectors are responsible for the compression or decompression of the meshwork and Schlemm's canal in this model, with compression decreasing, and decompression increasing aqueous humor outflow facility.
Aqueous Humor↗
Recurrent closure of neodymium: YAG laser iridotomies requiring multiple treatments in pseudophakic pupillary block.
We present a rare case of repeated closure of Nd:YAG laser iridotomies and recurrent iris bombe configuration with angle-closure attacks in a pseudophakic eye. Until recently, patent Nd:YAG laser iridotomies were considered incapable of being closed, and the only reported closure was in an eye with concomitant iritis. Our patient developed iris bombe five times following extracapsular extraction, anterior vitrectomy, and anterior-chamber intraocular lens implantation. The first occurred following closure of the surgical iridectomy; the next three times, following closure of previously patent Nd:YAG iridotomies; and the final episode occurred despite patent iridotomies. This last time one drop of pilocarpine 2% was administered and resulted in immediate iris flattening and reopening of the third iridotomy. Possible mechanisms for closure of the Nd:YAG iridotomies in this case are discussed. We suggest the combination of Nd:YAG laser iridotomies and the stretching of the iris by pilocarpine might have liberated the trapped aqueous humor behind the iris, maintaining the patency of the iridotomies and the depth of the anterior chamber.
Cataract Extraction↗
Trabeculectomy with resection of ciliary processes in glaucoma following scleral buckling.
We report a case of glaucoma following scleral buckling that required filtering trabeculectomy. Despite anterior entry to the anterior chamber, swollen ciliary processes were incarcerated in the sclerostomy site, blocking aqueous flow. Resection of the occluding ciliary processes resulted in restoration of aqueous flow through the sclerostomy. This case demonstrates that anterior rotation of the ciliary body and processes plays an important role in the pathogenesis of glaucoma following scleral buckling operation.
Aged↗
Neodymium:YAG laser trabeculopuncture in juvenile open-angle glaucoma.
The authors performed neodymium:YAG (Nd:YAG) laser trabeculopuncture (YLT) in eight eyes of six patients with uncontrolled juvenile open-angle glaucoma. Two methods of treatment were evaluated: either two confluent trabeculotomies, each 1 clock hour in extent; or focal treatment in four quadrants. In six eyes (75%), the intraocular pressure (IOP) was controlled (less than or equal to 19 mmHg) after a mean follow-up period of 6 +/- 2 months. All successful treatments were associated with blood reflux from the site of trabeculopuncture into the anterior chamber at the time of the procedure. Energy levels required for a single trabeculotomy (1 clock hour in extent) and for one focal trabeculopuncture, were 156 +/- 59 mJ and 42 +/- 24 mJ, respectively. The clinical results suggested that confluent trabeculotomy may be superior to focal treatment. No major complications were encountered with either treatment. The authors propose the use of YLT in uncontrolled juvenile glaucoma before surgically invasive goniotomy or filtration operations.
Adolescent↗
Alterations of aqueous humour outflow following argon laser trabeculoplasty in monkeys.
We performed argon laser trabeculoplasty in one eye in each of three cynomolgus monkeys, leaving the contralateral eyes as controls. Four weeks later in both eyes of each monkey we infused cationized ferritin as a tracer of the aqueous outflow pathways for 30-40 minutes before fixation. In the control eyes cationized ferritin was found throughout the conventional aqueous outflow tract, labelling trabecular endothelial cells, both inner and outer walls of Schlemm's canal, and the collecting channels. No permeation of cationized ferritin through continuous cellular layers such as the corneal endothelium was detected. In the lasered spots of the treated eyes cationized ferritin was found to label the cellular sheet covering the trabecular scar at the lasered site, but no tracer was detected within the scar or in Schlemm's canal immediately beneath. In contrast in adjacent non-lasered regions the trabecular cells, the observed juxta-canalicular herniations, and the vacuoles of the inner wall as well as Schlemm's canal itself were extensively labelled. Our findings suggest impermeability to aqueous humour flow through the actual lasered lesion, with shift of flow to adjacent, non-lasered regions. In the normal monkey these regions compensate structurally and functionally in ways that may help to deal with this diverted flow.
Animals↗
Increased intraocular pressure following endarterectomy.
Two patients are presented with neovascularization of the iris due to ischemia secondary to decreased blood flow through the carotid arteries. Panretinal photocoagulation was followed by regression of the new iris blood vessels to a greater extent in one patient than in the other. Following carotid endarterectomy, intraocular pressure increased, and, in one case, filtering surgery was required. Possible mechanisms for the rise in intraocular pressure following carotid endarterectomy are discussed.
Carotid Artery Diseases↗
Alteration of trabecular aqueous flow after cataract extraction.
Two human eyes that had undergone intracapsular cataract extraction were perfused with cationized ferritin. In both eyes segmental areas of trabecular meshwork collapse were demonstrated superiorly, adjacent to the cataract incision. Electron-microscopic study of these regions disclosed no labeling of the trabecular beams and trabecular spaces, suggesting impermeability to aqueous flow. In other regions, a diffuse labeling with cationized ferritin was demonstrated throughout the trabecular spaces, indicating aqueous flowthrough. Use of corneoscleral sutures may cause trabecular collapse and impermeability. When the collapse is extensive, subsequent increase in intraocular pressure may follow.
Aged↗
Complications of subconjunctival 5-fluorouracil following glaucoma filtering surgery.
The antimetabolite 5-fluorouracil (5-FU) has been used to inhibit fibroblastic growth to increase the success rate in glaucoma filtration surgery. Subconjunctival 5-FU can have adverse side effects. This paper describes two cases in detail of the ocular side effects of 5-FU. The first case is representative of the ocular surface problems. The second case deals with bleb leaks. Relative contraindications to 5-FU treatment are pre-existing ocular surface problems, early postoperative bleb leaks and fornix-based conjunctival flaps in filtering procedures. New drug delivery methods are presently being investigated to help decrease the adverse side effects and increase the efficacy of 5-FU.
Aged↗
Delayed response to argon laser trabeculoplasty in monkeys. Morphological and morphometric analysis.
In eight cynomolgus monkeys we performed argon laser trabeculoplasty and evaluated morphological changes in the trabecular meshwork (TM). Four weeks after laser treatment, the treated spots were detected as regions of flattened and collapsed beams covered by a cellular sheet extending from the corneal endothelium. The inner wall of Schlemm's canal beneath these regions was flat, with no vacuoles despite fixation with intraocular pressure maintained at 15 mm Hg. Adjacent nonlasered spots had wide open intertrabecular spaces with herniations of juxtacanalicular TM and of inner wall endothelium into and across the lumen of Schlemm's canal. The herniations contained chronic inflammatory cells and large vacuoles. Statistical morphometric analysis in three monkeys established that these herniations were significantly wider, more numerous, and contained more vacuoles than did control eyes. Our findings suggest that a biologic process is involved in these reactions to argon laser trabeculoplasty. Scarring is seen to obliterate TM in spots treated by the laser, and this apparently causes the flow of the aqueous humor to be diverted through adjacent nonlasered regions that become structurally altered to compensate for this overload of flow.
Animals↗
Use of cationized ferritin to trace aqueous humor outflow in the monkey eye.
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Animals↗
The use of glaucoma shell tamponade in leaking filtration blebs.
Our experience with the use of glaucoma shell tamponade for bleb leaks in six patients is described. All patients had posterior lip sclerectomies, with leaking blebs diagnosed intraoperatively (2 patients), early (2 patients) and late (2 patients) following surgery. The glaucoma shell works by applying a high resistance to excessive aqueous humor run-off through the leaking wound, and promotes conjunctival epithelial closure by approximating the wound edges. In all six cases the use of the glaucoma shell tamponade was fully effective. The leaks were sealed off and diffuse functioning filtering blebs were maintained, with very low intraocular pressure. We recommend the use of the glaucoma shell tamponade as the treatment of choice for bleb leaks prior to considering surgical repair.
Aged↗
Neodymium:YAG laser iridotomy as a possible contribution to lens dislocation.
We report on a patient with angle-closure glaucoma in the right eye that was apparently triggered by lens subluxation and tilting forward after trauma to the eye. Further inferior dislocation of the lens was detected after neodymium:yttrium aluminum garnet (Nd:YAG) laser iridotomy was performed superotemporally. We suspect that the Nd:YAG laser iridotomy, which was performed peripherally, might have induced further zonular rupture and lens dislocation due to a shock-wave effect, especially when the lens was already tilted forward. We suggest that the use of the Nd:YAG laser in cases in which subluxation of the lens is suspected should be considered as potentially hazardous.
Aged↗
Q-switched neodymium-YAG laser trabeculopuncture in monkeys.
In nine cynomolgus monkeys, trabeculopuncture was performed with a Q-switched neodymium-YAG laser, using a pulse energy of 5 to 7 millijoules and an exposure time of 14 nanoseconds. A penetration into Schlemm's canal was successfully achieved with two to four pulses; this penetration was accompanied by intraocular pressure (IOP) reduction and blood reflux into the anterior chamber. However, after eight days, IOP returned to baseline level, while white tissue was observed gonioscopically to fill in the puncture sites. Histologically, one hour after laser treatment, a blasting effect on the trabecular meshwork was observed with no signs of necrosis. Ater eight days, a hypertrophic scar formed, with the corneal endothelium extending over the scarred surface. At eight weeks and at six months after laser treatment, further shrinkage of the scar and the formation of a membrane over it was evident. Attempts to control scar formation by preventing blood reflux or injecting fluorouracil subconjunctivally for two weeks were unsuccessful. Scar formation at the trabecular puncture site severely limits the applicability of this potentially simple glaucoma treatment.
Animals↗
Short-term effect of argon laser trabeculoplasty in monkeys.
We performed argon laser trabeculoplasty (ALT) in four cynomolgus monkeys and evaluated the morphologic changes in the trabecular meshwork one hour and 14 hours following the laser treatment. One hour after ALT, disruption of the trabecular beams and coagulative necrosis of the tissue were evident. Fragmented cells and fibrillar tissue debris were found in the trabecular spaces, accumulating in the juxtacanalicular region. This might explain the elevation of intraocular pressure seen immediately following ALT in some glaucomatous patients. Also, many trabecular endothelial cells were rounded up, displaying different stages of leaving the beams; these cells were actively phagocytic. Such stimulation of trabecular meshwork cells with subsequent removal of tissue debris might explain the temporary nature of elevation of intraocular pressure following ALT.
Animals↗
Neodymium: YAG laser trabeculopuncture in open-angle glaucoma.
Ten eyes of eight patients with open-angle glaucoma (OAG) had neodymium (Nd):YAG trabeculopuncture performed in an investigational protocol as an alternative to surgical intervention. In each, at four to six sites in the mid-trabecular meshwork, three to six superimposed applications were made (2 to 6 mJ). In four of six patients with adult OAG, a small decrease in intraocular pressure (IOP) was noted (from a mean of 25.5 to 20.0 mmHg after 3-4 weeks in the treated eyes, compared to no change at 21 mmHg in the fellow eyes). There appeared to be further attenuation of this IOP effect over the subsequent 2 to 11 months, and all patients demonstrated gonioscopic closure of all the puncture sites with time. One patient demonstrated an acute IOP elevation to 58 mmHg after the procedure, necessitating emergency filtration surgery. In contrast, in four eyes of two patients with juvenile open angle glaucoma, a dramatic lowering of IOP and improvement in tonographic outflow facility was demonstrated, although the effects were only temporary in one patient. YAG laser treatment to the trabecular meshwork may have its greatest potential usefulness when abnormalities in the uveal meshwork are involved, such as in certain cases of juvenile or congenital glaucoma, and may help identify the need for a surgical goniotomy. With more usual forms of OAG, however, widespread use of this technique should be avoided until greater efficacy can be achieved.
Adolescent↗
A system for evaluating the earning capacity of the disabled.
A comprehensive system for evaluating the earning capacity of disability benefit claimants was developed. It is based on theoretical considerations of the factors constituting the loss of such capacity, and involves assessments made by a multi-disciplinary team (including at least a rehabilitation physician, registered nurse, psychologist and a social worker). Each team member conducts an assessment by means of a questionnaire with a strong emphasis on the claimant's functional capacity. In this study the physician was requested to evaluate the claimant according to a "profile of insufficiencies" in addition to the traditional percentage system which is used to reflect the degree of impairment. The results obtained with the first sample of 50 examinees are reported in this paper. The comprehensiveness of the variables covered by the team are demonstrated. A composite score agreed upon by the team was a better predictor of the final degree of disability (determined by an independent disability commission) than each team member's independent assessment. In addition, the "profile of insufficiencies", representing a functional approach to the medical evaluation, proved to be superior to the percentage system commonly used.
Adult↗