Biomedical subjects

D K Heuer

Publications and source records attributed to D K Heuer.

At least 37 records · Page 2Linked to original sources

PubMed1994

Rhegmatogenous retinal detachment after Molteno glaucoma implant surgery.

BACKGROUND: The Molteno implant is a device used for surgical treatment of complicated glaucoma. Rhegmatogenous retinal detachment (RD) is a relatively rare complication of Molteno implant surgery. This study was undertaken to evaluate the clinical features including the surgical management and postoperative outcome of patients with rhegmatogenous RD after Molteno implant surgery. METHODS: The authors reviewed 350 consecutive patients who had Molteno surgery and identified 16 patients with subsequent rhegmatogenous RD. They also studied one patient referred for RD repair after Molteno surgery at another institution. RESULTS: The risk of rhegmatogenous RD was 5%. Seventy percent (12/17) of the patients presented within 4 months of the Molteno procedure. Dialysis and flap tear were the most common types of retinal break found. Forty-one percent (7/17) of the patients had proliferative vitreoretinopathy. In three patients, clinical features suggested RD resulting from the Molteno procedure. In other patients, previous ocular surgery and underlying ocular disease may have contributed to the development of RD. Retinal detachment repair was attempted in all patients. Among 16 patients with at least 6 months of follow-up, 56% (9/16) had successful retina attachment. Forty-four percent (7/16) of the patients maintained formed vision. Eighteen percent (3/16) of the patients maintained visual acuity of at least 20/40. Intractable glaucoma did not develop in any of the patients with an attached retina. Recurrent RD, endophthalmitis, cyclitic membrane, or intractable glaucoma led to phthisis bulbi or enucleation in 44% (7/16) of the patients. CONCLUSION: A combined approach by vitreoretinal and glaucoma surgeons can restore vision and maintain glaucoma control in patients with rhegmatogenous RD associated with Molteno implant surgery.

Adolescent↗

PubMed1994

Initial clinical experience with the baerveldt implant in complicated glaucomas.

BACKGROUND: The Baerveldt glaucoma implant is an aqueous shunting device with a large surface area that is installed through a conjunctival incision in one quadrant of the eye. This study presents the initial results of the first 13 patients who underwent Baerveldt implantation as part of the Food and Drug Administration approval process. METHODS: Thirteen patients with medically uncontrollable complicated glaucomas underwent one-stage implantation of either a 200- or 350-mm2 Baerveldt implant without postoperative systemic antifibrosis therapy. Surgical success was defined as intraocular pressure greater than or equal to 6 and less than or equal to 21 mmHg without glaucoma reoperation or devastating complication. RESULTS: Eight patients (62%) had successful surgical outcomes, with a mean follow-up of 17.3 +/- 7.0 months (+/- standard deviation) (range, 6-24 months). Seven (70%) of the ten patients with glaucomas associated with aphakia or pseudophakia had successful outcomes, whereas only one (50%) of the two patients with neovascular glaucomas had a successful outcome. One patient with glaucoma associated with nanophthalmos and an unsuccessful filtering procedure had a failed outcome. The postoperative visual acuities remained within one line of the preoperative visual acuities or improved in 62% of the patients. The most frequent complications among all patients were transient serous choroidal effusion (23%) and hyphema (15%). CONCLUSION: Initial results of the Baerveldt implant generally are comparable with other implants. It is easier to install and requires less extensive conjunctival dissection than other large implants. Additional studies are needed to evaluate the effectiveness of the Baerveldt implant in affording long-term intraocular pressure control.

Adult↗

PubMed1993

Echographic evaluation of glaucoma shunts.

BACKGROUND: It is frequently impossible to determine by clinical examination alone if a filtering bleb is present over the equatorial plate(s) of a glaucoma shunt. This uncertainty can result in management dilemmas when patients with these devices have elevated intraocular pressures (IOPs). The authors describe how standardized echography can be used to determine if fluid is present around the plates and to characterize the blebs. METHODS: Four hundred twenty-seven plates in 269 patients who had undergone single- or double-plate Molteno implantation underwent standardized echography (both A- and B-scan examinations) to determine if blebs were present around the plates, primarily when results of slit-lamp examinations had been inconclusive. Bleb sizes, locations, and characteristics also were evaluated. RESULTS: Sixty-five percent of the plates had associated blebs, which were graded according to their sizes (small, medium, and large, in 29%, 44%, and 27% of plates with blebs, respectively). Fluid (which appeared as an echolucent area) could be seen underlying and/or overlying the plates (which appeared as echodense lines). Larger blebs were often associated with scleral flattening. Although bleb sizes did not necessarily correlate with the levels of IOP control, the presence of a bleb on ultrasound was indicative of tube patency. CONCLUSION: Standardized echography was invaluable in the postoperative management of patients who had undergone Molteno implantation because it demonstrated the presence or absence of blebs and characterized them when results of slit-lamp examinations had been inconclusive. This technique also can be used to evaluate similarly designed aqueous shunting devices.

Adult↗

PubMed1993

Trabeculectomy and Molteno implantation for glaucomas associated with uveitis.

PURPOSE: This study compares the outcomes of trabeculectomy and Molteno implantation in the treatment of glaucomas associated with uveitis. METHODS: Forty-five patients with uveitis, who had undergone filtering surgery for glaucomas associated with uveitis, were reviewed retrospectively. Successful outcome was defined as final intraocular pressure (IOP) of 6 to 21 mmHg, with a minimum follow-up of 6 months without visually devastating complications or loss of light perception. RESULTS: One- and two-year life-table success rates, respectively, were 81% and 73% with trabeculectomy (16 patients); 53% and 31% with combined trabeculectomy and first-stage (reserve) Molteno implantation (19 patients); and 79% and 79% with one-stage Molteno implantation (10 patients). In 11 patients who underwent second-stage Molteno implantation after trabeculectomy failure, 1- and 2-year life-table success rates were 79% and 79%, respectively. Complications included surgically treated choroidal effusions (1/45; 2%), choroidal hemorrhages (3/45; 7%), and chronic hypotony (3/45; 7%). Follow-up in all groups ranged from 5 to 70 months (mean +/- standard deviation, 28 +/- 17 months). CONCLUSIONS: Trabeculectomy provides surprisingly good results in glaucomas associated with uveitis (modulation of wound healing with antimetabolites probably would afford an even higher success rate). However, when significant, immediate postoperative and/or moderate chronic postoperative inflammation is likely, aqueous drainage devices appear more likely to control IOP.

Adult↗

PubMed1993

Mitomycin-C concentration in human aqueous humour following trabeculectomy.

The aim of the study was to determine mitomycin-C (MMC) concentrations in human aqueous humour during trabeculectomy and to correlate anterior chamber concentrations with method of application. MMC was applied intra-operatively by saturating sponges, ranging in size from 2 x 2 x 5 mm to 2 x 4 x 10 mm on dry cut, with 0.5 mg/ml MMC during trabeculectomy for 3-5 minutes. Applications to episclera were made in 18 cases and to the scleral bed after scleral flap dissection in 9 cases. Aqueous samples were collected by paracentesis with a 30 gauge needle 2-7 minutes after removal of sponge and external irrigation. Aqueous MMC concentrations were determined by high-performance liquid chromatography. Aqueous MMC concentration in 27 samples ranged from below minimum detectable concentration (less than 5 ng/ml) to 120.8 ng/ml. Mean aqueous drug levels obtained when the applications were to the scleral bed were 35.65 +/- 39.17 ng/ml (range 5-120.8 ng/ml). Applications on episclera gave mean aqueous concentrations of 4.98 +/- 9.11 ng/ml (range 0-33.3 ng/ml). The difference was statistically significant (p = 0.004). There were no correlations between sponge size, time of MMC exposure and aqueous MMC level. In conclusion, MMC is detectable in aqueous humour within minutes of external application and the aqueous concentration level is higher if the application is in the scleral bed than on the episclera. Toxicity of the drug at this concentration range for corneal endothelial cells needs further investigation via in vitro and clinical studies.

Adolescent↗

PubMed1992

Incidence and management of glaucoma after intravitreal silicone oil injection for complicated retinal detachments.

BACKGROUND: Intravitreal silicone oil injection used for managing complicated retinal detachments can be associated with elevated intraocular pressure (IOP). This study was undertaken to determine the incidence of glaucoma in patients who underwent silicone oil injection, as well as to evaluate the effectiveness of medical and surgical therapy in patients in whom glaucoma developed. METHODS: The postoperative courses of 50 eyes of 47 consecutive patients who underwent pars plana vitrectomy and silicone oil injection for the management of complicated retinal detachments were reviewed retrospectively. The outcomes of patients who underwent silicone oil removal and/or glaucoma surgery also were evaluated. RESULTS: The mean overall postoperative IOP before any glaucoma surgery was 16.7 +/- 9.3 mmHg (range, 0 to 45 mmHg), with a mean follow-up of 16.6 +/- 12.1 months (range, 2 to 51 months). Twenty-four (48%) eyes had postoperative IOPs of at least 25 mmHg and IOP elevations of at least 10 mmHg above the preoperative levels. Twenty-one (42%) eyes underwent complete removal of silicone oil and/or glaucoma surgery to effect IOP control. The IOPs were controlled to 21 mmHg or less (but > 5 mmHg) in 8 of 14 eyes that underwent removal of silicone oil alone, in 3 of 5 eyes that underwent Molteno implantation, and in 1 eye that underwent Nd:YAG transscleral cyclophotocoagulation, but not in 1 eye that underwent a modified Schocket procedure (mean follow-up, 13.5 +/- 11.0 months; range, 0.2 to 33 months). CONCLUSION: Intraocular pressure elevation is a common occurrence after intravitreal silicone oil injection. The underlying mechanism may often be multifactorial in nature. Patients in whom uncontrolled IOP develops may benefit from aggressive medical and/or surgical treatment with silicone oil removal, glaucoma implants, or cyclodestructive procedures.

Adolescent↗

PubMed1992

Which is better? One or two? A randomized clinical trial of single-plate versus double-plate Molteno implantation for glaucomas in aphakia and pseudophakia.

PURPOSE: Previous studies have suggested that primary double-plate Molteno implantation may be beneficial. Therefore, the authors performed a randomized clinical trial to evaluate the relative effectiveness and safety of single- versus double-plate Molteno implantation. METHODS: From March 1988 to February 1990, 132 patients who underwent Molteno implantation for medically uncontrollable non-neovascular glaucomas in aphakia or pseudophakia were randomly assigned to receive either single- or double-plate implants. RESULTS: The 1- and 2-year life-table success rates (success [survival] defined as 6 mmHg < or = final intraocular pressure [IOP] < or = 21 mmHg without additional glaucoma surgery or devastating complication) were 55% and 46% with single-plate implantation and 86% and 71% with double-plate implantation, respectively. The final postoperative visual acuities were within one line of the preoperative visual acuities or had improved in 73% and 80% of patients, respectively. Choroidal hemorrhages and/or effusions, corneal decompensation, flat anterior chambers, and phthisis bulbi were more common in the patients who had undergone double-plate Molteno implantation; however, transient elevations of IOP during the first few postoperative months were more common in the patients who had undergone single-plate Molteno implantation. CONCLUSIONS: Double-plate Molteno implantation more frequently affords IOP control than single-plate Molteno implantation; however, double plates are associated with greater risks of choroidal hemorrhages and/or effusions, corneal decompensation, flat anterior chambers, and phthisis bulbi.

Adolescent↗

PubMed1992

Clinical experience with the single-plate Molteno implant in complicated glaucomas. Update of a pilot study.

Ninety-six patients who had undergone single-plate Molteno implantation for glaucomas with poor surgical prognoses were re-evaluated for long-term results. Control of intraocular pressure was achieved with one single-plate implant to a level less than 22 mmHg (but greater than 5 mmHg) without reoperation or devastating complications in 46% of the aphakic/pseudophakic eyes, 25% of eyes after failed filters, 25% of eyes with neovascular glaucomas, and 26% of eyes in patients younger than 13 years of age (life-table analysis at 5 years). Five-year success rates improved to 53%, 71%, 40%, and 56%, respectively, when data from second plates were included. Visual acuities improved or remained the same after one or two plates were implanted in 47% of aphakic/pseudophakic eyes, 17% of eyes after failed filters, 65% of eyes with neovascular glaucomas, and 63% of eyes in patients younger than 13 years of age on whom Snellen acuity was available. The most frequent overall complications after implantation of one or two plates included: corneal edema (19%), corneal graft decompensation (13%), and cornea-tube touch, retinal detachment, and cataract (8% each).

Adolescent↗

PubMed1991

Combined Molteno implantation and pars plana vitrectomy for neovascular glaucomas.

Ten patients underwent combined Molteno implantation and pars plana vitrectomy as the primary nonlaser surgical treatment of neovascular glaucoma associated with diabetic retinopathy (9 patients) or central retinal vein occlusion (1 patient). Combined surgery was performed most frequently because media opacities precluded adequate preoperative retinal ablation. Follow-up ranged from 3 to 43 (mean +/- standard deviation, 18.0 +/- 13.2) months. Six patients achieved final intraocular pressures less than 22 mmHg. Visual acuities remained the same or improved in four patients. Four patients had uncomplicated courses. Among the other patients, complications included: recurrent vitreous hemorrhage and retinal detachment (3 patients each); hyphema (2 patients); and tube block, extensive fibrin formation, epiretinal membrane, and total retinal necrosis (1 patient each).

Adult↗

PubMed1991

Molteno implantation for glaucoma in young patients.

Seventy patients younger than 21 years of age underwent Molteno implantation for nonneovascular glaucoma. Fifty-three (76%) patients had failed angle and/or conventional filtering surgery. Final intraocular pressure less than 22 mmHg (but over 5 mmHg) was achieved in 40 (62%) of the 65 patients with at least 6-month follow-up (range, 6 to 59 months; mean +/- standard deviation, 22.7 +/- 14.1 months); however, only 22 (34%) were controlled after the initial Molteno implantation procedure, and 54 (83%) patients underwent further glaucoma and/or nonglaucoma surgical procedures. The visual acuities remained within one line of their preoperative levels or improved in 25 (68%) of the 37 patients on whom Snellen acuities were available. The most frequent complications included: tube-cornea touch (20%, transient in 3%), corneal edema (17%), retinal detachment (16%), tube block (10%), cataract (9%), chronic hypotony or phthisis (9%), pupillary or cyclitic membrane (9%), hyphema (7%), flat anterior chamber (6%), and large postoperative choroidal effusion (6%). Despite the high rates of subsequent surgical interventions and complications, Molteno implantation has been a useful approach for achieving intraocular pressure reduction in young patients with glucoma.

Adolescent↗

PubMed1991

Apraclonidine prophylaxis for postcycloplegic intraocular pressure spikes.

A randomized, prospective, double-masked study was undertaken to determine the risk of postcycloplegic intraocular pressure spikes in patients with open-angle glaucoma and to evaluate apraclonidine prophylaxis in minimizing these spikes. Patients were stratified as miotic treated or untreated and each group was randomized to receive either placebo (artificial tears) or apraclonidine in both eyes before instillation of tropicamide. In both the miotic treated and untreated groups that received placebo, there was a high incidence, (37% and 38%, respectively) of clinically significant (greater than or equal to 6 mmHg) intraocular pressure spikes after instillation of tropicamide. In both the miotic treated and untreated groups, there was a statistically significant difference in postcycloplegic intraocular pressure between the subgroup that received placebo and the group that received apraclonidine prophylaxis (P = 0.003 and P = 0.006, respectively). Additionally, four eyes that received placebo had a spike of over 10 mmHg (range, 12 to 27 mmHg), while only one eye had an increase of greater than 10 mmHg (12 mmHg) in the apraclonidine group. Thus, apraclonidine appears to be a useful agent for minimizing precipitous increases in intraocular pressure after cycloplegia in eyes of open-angle glaucoma patients prone to this complication of cycloplegia.

Adrenergic alpha-Agonists↗

PubMed1990

Primate trabeculectomies with 5-fluorouracil collagen implants.

Bilateral trabeculectomies were performed on four normal cynomolgus monkeys. Highly purified bovine skin collagen implants with either 1 mg of 5-fluorouracil or physiologic saline (one each per monkey by randomized, masked assignment) were sutured under the scleral flaps. The randomization code was not broken until all clinical and histopathologic observations had been completed. Six weeks postoperatively, the 5-fluorouracil-treated eyes had more deeply open internal trabeculectomy ostia than the control eyes; however, the intraocular pressures were indistinguishable, the filtering blebs were only minimally different, and half of each group had trace or mild anterior subcapsular lenticular changes. Histologically, a multinucleated foreign body giant cell reaction was evident in all of the collagen implants, but the 5-fluorouracil-treated eyes had less vigorous or delayed reactions compared to the control eyes. The collagen implant appears to be a poor drug delivery system in this model of glaucoma filtering surgery, because it incites a granulomatous inflammatory reaction.

Animals↗

PubMed1990

Molteno implantation for secondary glaucomas associated with advanced epithelial ingrowth.

Nine patients with advanced epithelial ingrowth underwent Molteno implantation for medically uncontrollable secondary glaucomas. Substantial reductions in intraocular pressures (IOPs) were observed in most patients (preoperative IOPs ranged from 5 to 48 mmHg [mean +/- standard deviation, 33.6 +/- 14.6 mmHg]; postoperative IOPs ranged from 10 to 30 mmHg [mean +/- standard deviation, 16.0 +/- 6.5 mmHg]); follow-up ranged from 9 to 47 months (mean +/- standard deviation, 18.8 +/- 12.1 months). Seven (78%) patients had final postoperative IOPs of less than 22 mmHg, five (56%) retained formed vision (visual acuity of at least 1/200), and six (67%) remained comfortable. Postoperative complications related to Molteno implantation included one case each of: conjunctival wound leak, vitreous-tube block, tube-cornea touch, and iris-tube block (or tube retraction). Complications attributed to epithelial ingrowth included five cases of corneal decompensation with band keratopathy. Molteno implantation is an effective technique for palliative treatment of secondary glaucomas associated with advanced epithelial ingrowth, frequently maintaining modest vision and comfort in eyes in which the intraocular epithelialization is too extensive for surgical removal and/or destruction.

Adult↗

PubMed1989

The influence of decreased retinal illumination on automated perimetric threshold measurements.

Decreased retinal illumination (such as can be caused by pupillary constriction or light absorption by ocular media opacities) was simulated with a randomly ordered series of neutral density filters in front of the right eyes of five subjects with dilated pupils. Threshold measurements were performed on Humphrey and Octopus perimeters at 0, 5, 10, 15, 20, and 25 degrees nasally along the 180-degree meridian. A 0.6-log unit neutral density filter, which reduces retinal illumination the equivalent of halving the pupillary diameter, decreased the mean Humphrey thresholds by 1.1 +/- 0.8 decibels (dB) (mean +/- standard deviation) and the mean Octopus thresholds by 1.7 +/- 1.4 dB. Statistically significant (P less than or equal to .05, Dunnett's test) threshold depressions were observed at all eccentricities with a 1.5-log unit neutral density filter on the Humphrey perimeter (-4.5 +/- 0.7 dB) and with a 1.0-log unit neutral density filter on the Octopus perimeter (-3.5 +/- 1.0 dB).

Adult↗

PubMed1988

The influence of simulated light scattering on automated perimetric threshold measurements.

The effect of light scattering by ocular media opacities on OCTOPUS and Humphrey perimeter threshold measurements was simulated with randomly ordered sequences of six ground-glass diffusers in the right eyes of five subjects. Threshold measurements were performed at 0 degrees, 5 degrees, 10 degrees, 15 degrees, 20 degrees, and 25 degrees nasally along the 180 degrees meridian with the F4 program on an OCTOPUS perimeter, and with twice-repeated profiles on a Humphrey perimeter. The reduction in differential light sensitivity correlated well with the 2.7-dB to 16.7-dB reduction in stimulus intensity caused by the 46% to 98% scattering of incident light by the diffusers. Contrast sensitivity in the presence of a glare source (Miller-Nadler glare test) was also affected by the diffusers, such that a 75% contrast target was not visible through the strongest diffuser whereas a 5% contrast target was visible without a diffuser. Conversely, the diffusers had very little effect on visual acuity measurements that were performed with projected high-contrast targets in a darkened room. Our data suggest that even minimal light scattering, such as might be caused by a cataract that has a relatively insignificant effect on visual acuity, may influence threshold measurements.

Adult↗

PubMed1988

Clinical experience with the single-plate Molteno implant in complicated glaucomas.

Ninety patients with medically uncontrollable glaucomas and poor surgical prognoses received single-plate Molteno implants (Optomat Supplies, Dunedin, New Zealand) without postoperative adjunctive systemic antifibrosis therapy. Eleven patients had insufficient follow-up for assessment of intraocular pressure (IOP) or visual acuity outcome. The initial Molteno implant procedures in the remaining 79 patients were successful (IOP less than or equal to 21 mmHg with at least 6 months' follow-up) in 26 (63%) of the 41 patients older than 12 years of age with non-neovascular glaucomas in aphakia/pseudophakia; 7 (70%) of the 10 patients older than 12 years of age with non-neovascular glaucomas in phakic eyes after failed filtering surgery; 7 (47%) of the 15 patients with neovascular glaucomas; and 7 (54%) of the 13 patients younger than 13 years of age with non-neovascular glaucomas. The visual acuities remained within one line of their preoperative levels or improved in 31 (76%) of the 41 aphakic or pseudophakic eyes with non-neovascular glaucomas; 3 (30%) of the 10 phakic eyes with non-neovascular glaucomas after failed filtering surgery; 10 (67%) of the 15 eyes with neovascular glaucomas; and 9 (100%) of the 9 eyes with non-neovascular glaucomas in patients younger than 13 years of age on whom Snellen acuity was available.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1988

Glaucoma update.

Explore the source record for details and available documents.

Glaucoma↗

PubMed1987

Clinical evaluation of the Oculab Tono-Pen.

We performed a clinical evaluation on a prototype version of the Tono-Pen hand-held tonometer. A masked, randomized design was used to compare the instrument with the Goldmann tonometer. We tested 270 eyes. For pressures of 6 to 24 mm Hg, the Tono-Pen tonometer measured, on average, 1.7 mm Hg higher than the Goldmann tonometer. This difference was statistically significant (P less than .0001). In the range above 24 mm Hg, no statistically significant difference was found in the pressures measured with the two instruments. Measurements made with the Tono-Pen were sufficiently close to those made with the Goldmann tonometer to be considered clinically accurate.

Evaluation Studies as Topic↗