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Biomedical subjects

G Baerveldt

Publications and source records attributed to G Baerveldt.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1992

Ab-interno neodymium:YAG versus erbium:YAG laser sclerostomies in a rabbit model.

This study was undertaken to determine whether thermally-induced tissue necrosis was a factor in ab-interno contact-laser sclerostomy failure. A rabbit model was used to compare the continuous-wave Neodymium (Nd):YAG with the pulsed Erbium (Er):YAG laser with respect to such failure. Laser energy was focused into a fused-silica fiber optic (400 microns) for the Nd:YAG laser (12 W; 3 to 5 seconds), and into a single-crystal, uncladded sapphire fiber optic (250 microns) for the Er:YAG laser (7 to 8 mJ; 250 microseconds; 6 to 8 pulses). The Nd:YAG and Er:YAG lasers required from 21 to 35 J and from 42 to 64 mJ, respectively, to create the sclerostomies. Filtering blebs and intraocular pressure reduction lasted longer (log-rank test; P less than .03) and surgical complications were fewer in the Er:YAG group than in the Nd:YAG group. By creating sclerostomies with minimal thermal damage, the Er:YAG laser may offer significant clinical advantages over lasers producing larger thermal effects.

Animals↗
PubMed1991

Laser trabecular ablation (LTA).

As part of a pilot study for glaucoma surgery, the use of 3 infrared solid state lasers with 4 fiber optic delivery systems to ablate human trabecular meshwork was investigated. Laser trabecular ablation (LTA) was attempted with the Erbium:YAG (2.94 microns), Erbium:YSGG (2.79 microns), and Holmium:YSGG (2.1 microns) lasers. Laser energy was delivered as a single pulse (250 microseconds) by tissue fiber optic contact with low hydroxyl-fused silica (200 and 500 microns), zirconium fluoride (250 microns), or sapphire (250 microns) fiber optics. Total energy required and thermal effects decreased as laser wavelength increased. LTA was best achieved at 2.94 microns (4 mJ total energy; energy densities = 8.2-12.7 J/cm2; pulse length 250 microseconds) with average thermal damage zones of 5.3-10.3 +/- 1.3-2.4 microns (means +/- SDs) to contiguous structures. This finding has potential applications in the surgical treatment of open-angle and congenital glaucoma and may minimize failure rates seen in other types of surgery on the trabecular meshwork where disrupted trabecular meshwork is not removed.

Aluminum Oxide↗
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

Management of the hypotonous cyclodialysis cleft.

Authoritative experience in the management of hypotonous cyclodialysis clefts is difficult to obtain because of their rarity. In this study, the authors describe nine patients with hypotonous cyclodialyses clefts: six patients were treated successfully with argon laser photocoagulation to the cleft surfaces; in one patient, cleft diathermy was used to seal an incompletely closed cleft after a single argon laser treatment; one patient responded to conservative management; another patient did not require treatment. Four cases followed ocular trauma and five occurred after extracapsular cataract extraction and posterior chamber intraocular lens implantation. In three patients, the anterior chamber was too shallow to permit gonioscopy; sodium hyaluronate (Healon) was used to reform the anterior chamber, to delineate the extent of the cyclodialysis cleft, and to provide maximal access for the argon laser treatment. In another patient, laser cleft consolidation was successful only after fully opening the cleft with sodium hyaluronate. The evolution of the laser photocoagulation technique used by the authors is described. Laser cyclodialysis cleft consolidation can be repeated easily and safely. The authors recommend argon laser photocoagulation as the primary management approach. Intracameral viscoelastic agents are useful adjuncts. The complications of cleft lasering are minor, although a hypertensive episode commonly occurs in the early postoperative period as the cleft closes. Major intraocular surgeries usually can be avoided.

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↗
PubMed1991

Hemorrhagic choroidal detachment with anterior vitreoretinal adhesions.

We present three cases of large intraoperative or postoperative hemorrhagic choroidal detachment with subsequent adherence of the retina to anterior segment structures. Surgical management involved bimanual vitrectomy through anterior sclerotomy sites and dissection within the anterior segment. Successful retinal reattachment was achieved in two of these cases (18-months' follow up). In the third case, the retina remained attached for 4 months but then redetached.

Adolescent↗
PubMed1991

Infrared laser sclerostomies.

Four solid-state lasers with three fiberoptic delivery systems were used to perform laser sclerostomies in an acute-injury rabbit model and in fresh human globes. The lasers used were continuous-wave neodymium:yttrium aluminum garnet (YAG, 1.06 microns) and pulsed holmium:yttrium scandium galliam garnet (YSGG) (2.10 microns), erbium:YSGG (2.79 microns), and erbium:YAG (2.94 microns). Thermal damage to tissue and total laser energy required to produce sclerostomies decreased with increasing wavelength. In human tissue using a 600-microns fused silica fiberoptic, maximum thermal damage (greater than or equal to 100 microns) was noted at 1.06 microns with a total energy of 21 J at a power density of 2.5 kW/cm2. In addition, focal damage to the iris and ciliary body was noted at this wavelength. The least amount of thermal damage (15-20 microns) and lowest total energies needed were found at 2.94 microns. A 250-microseconds pulse length and pulse radiant exposures of 3.6 J/cm2 and 14.3 J/cm2 were used for the low hydroxyl-fused silica (500 microns) and zirconium fluoride (250 microns) fiberoptics, respectively. Although zirconium fluoride fibers have high through-put efficiencies that facilitate study of laser tissue interactions at 2.94 microns, problems encountered with fragility and solubility of the bare tip in aqueous media limit its usefulness. A high attenuation rate with the low hydroxyl-fused silica fiber limited its usable length to 35 cm at 2.94 microns. Tissue damage during sclerostomy formation was minimized at 2.94 microns, reaching a maximum at 1.06 microns. Minimizing tissue damage theoretically could decrease subconjunctival scarring and filtration failure.(ABSTRACT TRUNCATED AT 250 WORDS)

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

Gentamicin-resistant pseudomonal infection. Rationale for a redefinition of ophthalmic antimicrobial sensitivities.

Eight pseudomonal species were involved in 106 invasive infections of the eye; all were community acquired. Eighteen percent of the total and 9% of the Pseudomonas aeruginosa strains were gentamicin resistant, as defined using conventional criteria. All 10 cases of "resistant" pseudomonal (nine P. aeruginosa) keratitis responded satisfactorily to treatment with gentamicin. The resistance breakpoint (defined by safe serum levels in parenteral therapy) for most P. aeruginosa is much lower than ocular gentamicin levels achievable by optimal local application. We argue for a specific ophthalmologic definition of antibiotic resistance in infections of the cornea and external eye. MIC quantitative determinations of ocular isolates would provide more useful information to ophthalmologists than conventional qualitative disc sensitivity testing.

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

Molteno implant for control of glaucoma in eyes after penetrating keratoplasty.

Seventeen patients (17 eyes) underwent implantation of a single plate Molteno implant for medically uncontrollable intraocular pressures after penetrating keratoplasty. Most of the eyes had extensive peripheral anterior synechiae, and 16 of 17 (94%) were pseudophakic or aphakic following keratoplasty. Other glaucoma procedures had been performed previously on 13 eyes: argon laser trabeculoplasty (one eye), trabeculectomy (seven eyes), transpupillary argon laser cyclophotocoagulation (three eyes), and cyclocryotherapy (three eyes). Follow-up ranged from 5 to 28 months (mean, 13 months). Three eyes underwent repeat Molteno implantation when intraocular pressure (IOP) was not satisfactorily reduced after the first procedure. Considering one eye with chronic hypotony as a failure, 12 of 17 eyes (71%) had IOPs of less than 21 mmHg at the time of the three most recent postoperative examinations after a single Molteno implant. Repeat implants in three eyes increased the number of eyes with IOPs of less than 21 mmHg to 14 (82%). Corneal allograft rejection after Molteno implantation occurred in seven eyes; two of these were successfully reversed with corticosteroid therapy. Three of the five eyes with irreversible graft rejection were regrafted, and two of these grafts have remained clear. Including the regrafted eyes, 13 eyes had clear grafts and controlled IOPs at the most recent postoperative examination. The Molteno implant may prove useful in the management of medically uncontrollable glaucoma following penetrating keratoplasty; however, there appears to be a substantial risk of postoperative graft rejection.

Adult↗
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↗
PubMed1984

Flurbiprofen pretreatment in argon laser trabeculoplasty for primary open-angle glaucoma.

We examined the influence of topically administered flurbiprofen sodium 0.03%, a potent prostaglandin inhibitor, on the inflammatory response and intraocular pressure following argon laser trabeculoplasty. Our investigation included one eye of each of 118 patients with primary open-angle glaucoma in whom laser trabeculoplasty was indicated. Sixty-three patients received flurbiprofen and 55 received a vehicle during the two-hour period immediately preceding laser therapy and for one week postoperatively. No significant differences in postoperative IOPs were noted between groups. However, when we considered conjunctival erythema at 24 hours or control of inflammation at the termination of the investigation, the eyes receiving flurbiprofen had less inflammation than did the vehicle-treated eyes.

Aged↗
PubMed1983

Pseudophakic serous maculopathy.

A 73-year-old woman experienced a serous macular detachment following an uncomplicated planned extracapsular cataract extraction with placement of a posterior chamber intraocular lens with general anesthesia. To our knowledge, this complication of cataract surgery, with or without lens implantation, has not been previously reported. The specific cause of this chorioretinopathy is not clear. Breakdown of the retinal pigment epithelium-Bruch's membrane-choriocapillaris barrier due to surgical procedure would appear to be the most likely cause. The macular detachment gradually resolved, leaving the patient with excellent visual acuity.

Aged↗
PubMed1983

Mucous membrane grafting for severe palpebral vernal conjunctivitis.

Vernal conjunctivitis usually can be managed medically. In the rare cases that do not respond to medical treatment, surgical intervention has been considered. Four cases of vernal conjunctivitis and one case of probable contact lens-induced giant papillary conjunctivitis were treated with palpebral conjunctival excision and application of a mucous membrane graft. All patients improved symptomatically, with follow-up ranging from 1 1/2 to 14 years. The only complication encountered was recurrence of giant papillae at the conjunctiva-mucous membrane graft junction. Conjunctival excision and mucous membrane grafting is a useful procedure in rare cases of particularly severe vernal conjunctivitis.

Adult↗