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Biomedical subjects

T W Perkins

Publications and source records attributed to T W Perkins.

16 recordsLinked to original sources
PubMed1998

The rarity of clinically significant rise in intraocular pressure after laser peripheral iridotomy with apraclonidine.

OBJECTIVE: To determine the incidence of intraocular pressure (IOP) rise of varying degrees after laser peripheral iridotomy (LPI) in patients with and without glaucoma treated perioperatively with pilocarpine and apraclonidine. DESIGN: A retrospective chart review. PARTICIPANTS: A total of 289 eyes in 179 patients with narrow occludable angles (NOA) (N = 148), open-angle glaucoma or ocular hypertension (OAG) (N = 115), or chronic-angle closure glaucoma (CACG) (N = 26) were reviewed. MAIN OUTCOME MEASURES: The difference between preoperative and postoperative IOP, absolute postoperative IOP, and the need for acute IOP-lowering treatment was noted. RESULTS: Only 1.1% (95% confidence interval [CI], 0.03%-5.8%; 1 of 94) of patients and 0.7% (95% CI, 0.02%-3.7%; 1 of 148) of eyes with NOA experienced a rise of more than 10 mmHg 1 to 2 hours after LPI. The incidence of postoperative IOP greater than 25 mmHg and acute postoperative IOP-lowering management was 0% (95% CI, 0%-3.8%). Intraocular pressure in 1 of 115 eyes (0.9%, 95% CI, 0.02%-4.7%) with OAG rose more than 10 mmHg, requiring acute treatment. None of the 26 CACG eyes experienced a rise of more than 10 mmHg (95% CI, 0%-13.2%). CONCLUSION: The IOP rise that requires further intervention after LPI with the perioperative use of pilocarpine and apraclonidine is very uncommon. In patients with NOA, routine postiridotomy IOP monitoring may not be required.

Adrenergic alpha-Agonists↗
PubMed1998

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Filtering Surgery↗
PubMed1998

Molteno implant with mitomycin C: intermediate-term results.

PURPOSE: The authors examine the intermediate-term effects of adjunctive intraoperative mitomycin C (MMC) in a cohort of patients who received double-plate Molteno implants for complicated glaucomas. METHODS: A consecutive series of 21 patients who received MMC 0.5 mg/ml for 5 minutes as an adjunct to a double-plate Molteno implant was compared by life-table analysis to a historical control group of 18 patients who received either no adjunct or 5-fluorouracil (5-FU) but no MMC. RESULTS: At three years follow-up, 35% (95% confidence interval (CI), 15-57%) of patients who received MMC avoided failure criteria of intraocular pressure (IOP) less than 6 mm Hg or more than 21 mm Hg, addition of glaucoma medication, reoperation for glaucoma, or tube removal. Seventeen percent (95% CI, 4-37%) of patients in the control group at three years follow-up met similar criteria (p = 0.039). No late complications of tube erosion were seen in the MMC group. CONCLUSION: Intraoperative MMC offers an increased likelihood of a two- to three-year period of medication-free IOP control in patients undergoing double-plate Molteno implants, compared to similar patients receiving 5-FU or no adjunctive antimetabolite therapy.

Adult↗
PubMed1998

Trabeculectomy with mitomycin C: intermediate-term results.

PURPOSE: This study was performed to provide results 2 to 3 years after trabeculectomy with mitomycin C (MMC). METHODS: A consecutive series of all 68 patients who underwent trabeculectomy with MMC was analyzed using Kaplan-Meier life-table statistics and compared with other published retrospective analyses. RESULTS: At 2- and 3-year follow-up examinations, 59% (95% confidence interval [CI], 44-70%) and 47% (95% CI, 32-61%) of patients, respectively, avoided an intraocular pressure (IOP) of more than 21 mmHg or less than 20% below their preoperative level without glaucoma medication on two consecutive occasions more than 1 month apart after 3 months follow-up (75% [95% CI, 60-84%] and 70% [95% CI, 53-81%], respectively, with medication) and avoided additional glaucoma surgery. Loss of more than three lines of visual acuity on two occasions more than 1 month apart after 3 months follow-up occurred in 28% of patients (> 2 lines in 44%) at 3 years. Nonreversible causes of loss of three lines of acuity occurred in 13% of patients. Complications requiring reoperation occurred in 16% of patients and included hypotony maculopathy (4%) and late bleb leaks (4%). CONCLUSIONS: At the 3-year follow-up evaluation, trabeculectomy with MMC provided an approximately 50% chance of maintaining IOPs less than 21 mmHg and a more than 20% IOP reduction without concomitant use of glaucoma medication, which increased to 70% with the addition of medication. This procedure was associated with an approximately 30% risk of substantial visual loss (approximately 15% nonreversible) and a 15% chance of reoperation for complications.

Adult↗
PubMed1997

Measuring column void volumes with NMR.

A novel method for measuring resin porosities and column void volumes with fluorine. NMR has not been developed. In situ measurements of the void volumes accessible to an array of fluorinated probe molecules are used to characterize the pore size distribution of the media. Application of this simple procedure is demonstrated for a commercially packed column and several bulk resins. The porosity distributions obtained by this technique are similar to those obtained by size exclusion chromatography. Unlike chromatographic tracer studies, however, this method does not require packed columns.

Magnetic Resonance Spectroscopy↗
PubMed1997

A "clothesline" suture technique for the repair of a conjunctival tear during trabeculectomy.

This report describes a new technique for the intraoperative repair of a conjunctival tear during trabeculectomy. A single suture was used in a "clothesline" fashion to wall off the conjunctival defect from the aqueous flow, allowing the defect to scar closed. This technique will allow the surgeon to salvage a functioning bleb, thereby avoiding more radical surgical options.

Aged↗
PubMed1995

Adjunctive mitomycin C in Molteno implant surgery.

PURPOSE: The authors assessed the efficacy of adjunctive intraoperative mitomycin C to produce lower intraocular pressures (IOPs) in patients with complicated glaucoma who underwent double-plate Molteno implantation. METHODS: A pilot series of 21 consecutive patients who underwent double-plate Molteno implantation with adjunctive intraoperative mitomycin C (0.5 mg/ml) for 5 minutes was compared with a historical control group who received Molteno implants without mitomycin C (n = 18). With failure defined as an IOP greater than 21 or less than 6 mmHg at two observations 1 month apart, the addition of medication, re-operation for glaucoma, or tube removal, a life-table analysis of IOP was performed on patients with at least 3 months' follow-up. RESULTS: Success in the mitomycin C group was higher (68% at 1 year) than the control group (17% at 1 year; P = 0.006). Loss of more than one line of vision (33%) and re-operation for complications (including flat anterior chamber, choroidal detachment, and tube blockage) (38%) were slightly but not significantly more frequent in the mitomycin C group than in the control group. CONCLUSION: This study suggests that intraoperative mitomycin C in conjunction with Molteno implant may offer a better chance of achieving target IOPs in the low teens in patients with complicated glaucoma than Molteno implantation alone.

Adult↗
PubMed1994

Recalcitrant diplopia after implantation of a Krupin valve with disc.

We report, to our knowledge, the first case of a patient experiencing recalcitrant diplopia after implantation of a Krupin valve with disc for uncontrolled glaucoma. Despite multiple surgeries and adjustments in her glasses, the patient was left with residual and intolerable diplopia.

Aged↗
PubMed1990

Endophthalmitis after placement of a Molteno implant.

I report a case of early postoperative endophthalmitis following placement of a Molteno implant. Excellent results were obtained by immediate removal of the implant and surgical management of the infection, followed by replacement of the implant.

Adult↗
PubMed1988

Trabecular meshwork cells grown on filters. Conductivity and cytochalasin effects.

A system was developed to measure the hydraulic conductivity of cultured monolayers of human trabecular meshwork (HTM) cells. By optimizing the cell growth conditions and evaluating a number of filter supports, confluent HTM cells in single layers were obtained for measurement of hydraulic conductivity. The HTM monolayers had hydraulic conductivities of 0.3-2.0 microliters/min/mm Hg/cm2 measured at near-physiological flow rates. Evaluations of cytochalasin B (CB) effects on the hydraulic conductivity of our HTM monolayers revealed that CB (10(-6) to 10(-5) M) caused a dramatic dose-related increase in conductivity within 10 to 30 min, which parallels CB effects on outflow facility in vivo. Morphologic observations show that the increase in hydraulic conductivity was accompanied by a retraction of the trabecular cells and widening of the intercellular spaces. Our findings suggest that growth of HTM cells on filter supports can provide a useful in vitro system to study the regulation of aqueous outflow.

Adult↗
PubMedDate not supplied

Ocular motility defects in patients with the Krupin valve implant.

To determine the prevalence of ocular motility defects following placement of a Krupin valve with disk and adjunctive mitomycin-C in glaucoma patients, a retrospective case series of all patients receiving a Krupin valve with disk and intraoperative mitomycin-C in a university-based referral practice was conducted. Each of the seven consecutive patients undergoing placement of a Krupin valve with disk in one eye because of uncontrolled glaucoma, developed significant primary position heterotropia or limitation of ocular rotations. One patient had significant postoperative diplopia. We conclude that the Krupin valve with disk used with intraoperative mitomycin-C can be associated with the development of ocular motility defects. The limitation of rotations appears to relate to the combined mechanisms of implant and cyst bulk and the displacement of the oculorotary muscles by the encapsulating cyst.

Adult↗