Biomedical subjects

D S Minckler

Publications and source records attributed to D S Minckler.

At least 19 recordsLinked to original sources

PubMed1998

Trabeculectomy with intraoperative 5-fluorouracil.

BACKGROUND AND OBJECTIVE: To investigate the outcome and complication rates of trabeculectomy following the combined use of intraoperative, topical 5-fluorouracil (5-FU) and low-dose, postoperative subconjunctival 5-FU injections. PATIENTS AND METHODS: Forty-one eyes of 41 patients with advanced, medically uncontrolled glaucoma underwent trabeculectomy with intraoperative episcleral application of 5-FU (50 mg/ml for 5 minutes). A variable number of subconjunctival 5-FU injections were administered postoperatively at the discretion of the operating surgeon. RESULTS: Six-, 12-, and 15-month life-table success rates (5 mm Hg < or = intraocular pressure [IOP < or = 21 mm Hg) were 100%, 97%, and 83%, respectively. Mean postoperative IOP was 12.1 +/- 4.3 mm Hg. An average of 2.2 +/- 1.6 (range 0 to 7) supplemental subconjunctival 5-FU injections were administered postoperatively. Corneal epithelial erosions developed in 7 (17%) of the eyes. Five of 7 patients who underwent subsequent surgical procedures maintained successful control of IOP at an average of 11.0 +/- 4.8 (range 5 to 16) months after the secondary surgery. CONCLUSION: Trabeculectomy with intraoperative 5-FU is effective in controlling IOP while possibly minimizing the need for frequent postoperative injections and the occurrence of corneal epitheliopathy.

Adult↗

PubMed1997

Annular peripheral choroidal detachment simulating aqueous misdirection after glaucoma surgery.

PURPOSE: The purpose of the study was to define a newly recognized complication after glaucoma surgery and to recommend a therapeutic regimen. METHODS: Eighteen patients diagnosed initially as having aqueous misdirection after glaucoma surgery, but who subsequently were found by ultrasonography to have an annular peripheral choroidal detachment that resulted in secondary angle closure glaucoma, were studied. Ten of these patients were treated with topical cycloplegics and corticosteroids, and 8 were treated with drainage of suprachoroidal fluid. Outcomes of these two treatment methods were compared. RESULTS: Annular peripheral choroidal detachment reliably was diagnosed with ultrasonography. Of the variables studied, time elapsed before resolution of the annular peripheral choroidal detachment was noted to be statistically significant (P < 0.00005). Immediate resolution followed drainage of suprachoroidal fluid, whereas a mean of 19.6 days was required for resolution after medical therapy. CONCLUSIONS: Annular peripheral choroidal detachment should be considered in the differential diagnosis of a flat or shallow anterior chamber with normal or high intraocular pressure after glaucoma surgery. The diagnosis of annular peripheral choroidal detachment can be confirmed most reliably by ultrasonography. Medical therapy is as effective as is surgery, although a significantly longer time to resolution is required.

Adult↗

PubMed1996

Aqueous humor dynamics in rats.

BACKGROUND: In order to determine normal outflow facility and aqueous humor production values in Lewis rats, we established methods of measuring aqueous humor dynamics in this animal. METHODS: Outflow facility was determined using anterior chamber infusion with constant pressure. Aqueous humor production was determined by a technique of dilution with FITC-albumin. RESULTS: The mean outflow facility was 0.044 +/- 0.01 microliter/min/mmHg. Rats weighing less than 300 g had lower values than did rats weighing more than 300 g (0.034 +/- 0.006 microliter/min/mmHg vs 0.050 +/- 0.015 microliter/min/mmHg, P = 0.009). The mean aqueous humor production was 0.350 +/- 0.110 microliter/min. The turnover rate of aqueous humor production per minute was 2.23%. CONCLUSIONS: Anterior chamber infusion with constant pressure and the FITC-albumin method allow measurement of the outflow facility and aqueous humor production in Lewis rats. These methods may be useful in assessing aqueous humor dynamics when rats are used as a glaucoma model.

Animals↗

PubMed1996

Fascia lata patch graft in glaucoma tube surgery.

PURPOSE: To determine if using human cadaveric fascia lata grafts to cover glaucoma implant tubes is safe and effective. METHODS: All patients who underwent glaucoma implant surgery at the Doheny Eye Institute between July 1993 and September 1993 received a fascia lata patch graft to cover the subconjunctival portion of the tube. These patients were followed prospectively for clinical signs of conjunctival breakdown, graft melt, tube erosion, graft-related inflammation, infection, and graft-related complications. RESULTS: Twenty-two eyes of 21 patients were followed for a mean of 19 months. All eyes tolerated the fascia lata grafts well without clinical evidence of graft-related conjunctival, scleral, or intraocular inflammation. No tube erosion or melting of the graft was observed in the study group. CONCLUSION: Preserved donor fascia lata was well tolerated as a grafting material in glaucoma implant surgery. No clinical signs of graft rejection, foreign body reaction, tube erosion, or graft melt were observed in the study group during the follow-up period.

Adolescent↗

PubMed1996

Laser suture lysis after mitomycin C trabeculectomy.

PURPOSE: To evaluate the timing, efficacy, and complications of laser suture lysis (LSL) after mitomycin C trabeculectomy in patients with glaucoma at high risk for failure of filtering surgery. METHODS: The authors retrospectively reviewed the charts of 62 consecutive patients who underwent a total of 66 sessions of LSL after trabeculectomy with mitomycin C. RESULTS: The interval from surgery to LSL ranged from 2 to 65 days (mean +/- standard deviation, 17.9 +/- 14.9 days). The average intraocular pressure (IOP) reduction after LSL was 11.9 +/- 8.9 mmHg (range, 3-40 mmHg). A longer interval to LSL was correlated with a lesser degree of pressure reduction (P=0.0004, Wilcoxon rank-sum test). After LSL, hypotony developed in 13 (21%) patients (IOP < 6 mmHg on 2 consecutive measurements at least 24 hours apart). This resolved spontaneously after 7 to 304 days (104.1 +/- 109.1 days) in 12 (92%) of the 13 patients. Life-table success rates (success defined as 6 mmHg </= final IOP </= 21 mmHg) for the hypotony and no hypotony groups were 100% and 86% (at 6 months) and 96% and 86% (at 12 months), respectively. The final visual acuity worsened in a significantly greater percentage of patients in the hypotony group (46%) compared with the no-hypotony group (18%) (P = 0.06), Fisher's exact test). CONCLUSIONS: Laser suture lysis is safe and effective in augmenting aqueous filtration after mitomycin C trabeculectomy. A longer time interval between surgery and LSL may result in both a lesser degree of IOP reduction and a lower incidence of subsequent hypotony.

Adolescent↗

PubMed1996

Effects of intraoperative mitomycin-C on the function of Baerveldt glaucoma drainage implants in rabbits.

PURPOSE: The purpose of this study was to assess the effects of intraoperative mitomycin-C (MMC) on the function of Baerveldt glaucoma implants in rabbits. METHODS: Bilateral implantations of 200 mm2 Baerveldt drainage devices were performed in 30 normal albino rabbits. One eye, randomly selected, received intraoperative application of MMC at the site of the implant plate for 5 min, via a 6 x 4 x 2 mm cellulose sponge saturated with 0.5 mg/ml of MMC. The opposite eye served as a control. MMC-treated and control eyes (five animals each group) were compared for intraocular pressure (IOP), resistance to flow, flow rates through the implant and histopathological findings at 2, 4, 6, 12, and 24 weeks postoperatively. Resistance to flow and flow rates through the implants were studied after opening the cornea and connecting the drain tube to a micromanometric system. RESULTS: Preoperative IOP did not differ between groups. MMC-treated eyes had lower levels of IOP than did controls at all postoperative times. The differences in IOP were statistically significant up to 8 weeks postoperatively. Resistance to flow was lower in MMC-treated eyes at all times studied, but the differences were statistically significant only at the time points of 2, 4, and 6 weeks. Flow rates through the implant bleb were always higher in MMC-treated eyes, and statistically significant differences were seen at 2, 4, 6, and 24 weeks. Histopathologically, MMC-treated eyes had thinner implant capsules with delayed maturation and less inflammatory infiltrate. CONCLUSION: MMC causes lower IOP and higher perfusion rates through the implant capsule at 2, 4, and 6 weeks postoperatively. Wound dehiscence, bleb leaks, and extraocular muscle injury were observed only in MMC-treated eyes.

Administration, Topical↗

PubMed1996

Suprachoroidal hemorrhage after Molteno implantation.

PURPOSE: The objective of this study is to identify the rate and the associated risk factors for suprachoroidal hemorrhage (SCH) after Molteno drain implantation. METHODS: Data from the Molteno pilot study and single versus double-plate Molteno study were reviewed retrospectively for the occurrence of SCH. Follow-up intervals, demographic variables, ocular data, and medical history were collected. RESULTS: SCH occurred in 6% of the patients enrolled in the Molteno studies; all cases were delayed and none were intraoperative. Significantly associated factors in a multiple logistic regression for SCH were the extent of intraocular pressure (IOP) drop after surgery, the post-operative IOP, a diagnosis of angleclosure glaucoma, and possibly the number of prior surgeries as well. Eyes with SCH did significantly less well in terms of visual acuity outcomes and were more likely to have inadequately controlled IOP. CONCLUSIONS: This study suggests that SCH occurs at the same frequency after Molteno implantation as after filtering surgery with antimetabolite use and that eyes with SCH do less well.

Adult↗

PubMed1996

Long-term histologic studies of the Baerveldt implant in a rabbit model.

PURPOSE: The Baerveldt glaucoma implant is an aqueous shunting device with large surface area that is installed through a single-quadrant conjunctival incision. A rabbit model of the Baerveldt implant was created to obtain serial histology and clinical information over 1 year. METHODS: Modified versions of the Baerveldt implant (110 or 160 mm2) were implanted in 18 normal New Zealand white rabbit eyes. The rabbits were examined periodically and their intraocular pressures (IOPs) recorded. They were killed at monthly intervals to obtain histology of the bleb capsules. RESULTS: Thin capsules were present at 1 month, which consisted of lamellar collagen deposition surrounded by a granulomatous reaction with multinucleate giant cells. Inflammatory cells (probably macrophages) were scattered on the inner bleb surface. The granulomatous reaction resolved after 4 months. Subsequently, capsule thickness and cellularity remained relatively stable, although the collagen stroma became less compact over time. Sixteen rabbit eyes had initial IOP reductions of > or = 3 mm Hg compared with fellow eyes, which persisted up to 4 weeks postoperatively. Seven eyes (39%) exhibited a hypertensive phase (IOP exceeded that of fellow eye by > or = 3 mm Hg) from 2 weeks to 3 months postoperatively. CONCLUSION: The Baerveldt explant is surrounded by a fibrous capsule that matures over time. The bleb histology in the rabbit model is similar to that described with the Molteno implant in primates and humans, except for the eventual development of a fibroblastic inner lining in the rabbit model. This contrasts with primate and human models, in which the inner lining remains an open mesh.

Animals↗

PubMed1996

Interobserver and intraobserver variability in the detection of glaucomatous progression of the optic disc.

PURPOSE: To evaluate the potential value of obtaining follow-up stereoscopic photographs on glaucoma suspects in identifying progressive optic nerve damage. METHODS: Nineteen sets of stereoscopic optic disc photographs, reflecting one eye from each of 19 patients at two time points, were selected from the records of subjects enrolled in the Glaucoma Screening Study. By consensus, three experts judged 13 of these eyes to have progressive glaucomatous optic nerve damage. Four other ophthalmologists who were masked to the expert panel evaluation then assessed glaucomatous progression in the same eyes. They were asked to evaluate glaucomatous progression in three ways: first, by drawing the optic nerve head appearance from initial stereoscopic photographs and later comparing their own drawings to follow-up stereoscopic photographs; second, by comparing serial stereoscopic photographs directly; and third, by comparing drawings of the optic nerve head made by another examiner to the follow-up photographs. RESULTS: Neither sensitivity nor specificity was consistently better for serial stereoscopic photographs than for drawings. Individual ophthalmologist agreement rates with the expert panel's determinations of progression were 23-62% when examiners compared their own drawings to follow-up photographs, 54-71% when examiners compared serial stereoscopic photographs, and 38-85% when comparing another ophthalmologist's drawings to follow-up photographs. CONCLUSION: Baseline stereoscopic photographs of the optic nerve head did not substantially improve recognition of progressive glaucomatous optic nerve damage when compared with the use of baseline drawings of the optic nerve head made from photographs in subjects who developed visual loss in the interim.

Disease Progression↗

PubMed1996

Cataract surgery after trabeculectomy.

BACKGROUND AND OBJECTIVE: To determine the effect of cataract surgery on glaucomatous eyes with good intraocular pressure (IOP) control after trabeculectomy. PATIENTS AND METHODS: Twenty-two eyes with functional blebs that underwent cataract extraction were retrospectively analyzed. RESULTS: The mean (+/- SD) preoperative IOP was 11.0 +/- 4.3 mm Hg. The mean (+/- SD) postoperative IOPs at 1, 2, 6, and 9 months were 15.5 +/- 4.9, 12.6 +/- 4.7, 14.6 +/- 5.6, and 19.0 +/- 7.9 mm Hg, respectively. At each interval except for the second month, the mean IOP was statistically significantly higher than the preoperative value (P = .0003, .24, .02, and .0009, respectively). The total number of medications was also higher (3 preoperatively versus 27 postoperatively). The interval between the two surgeries had no influence on IOP control. Intraoperative complications during cataract surgery, particularly vitreous loss, were associated with poor IOP control. Phacoemulsification had less of an effect on the postoperative IOP control than did extracapsular cataract extraction. CONCLUSIONS: Eyes with previous successful trabeculectomies had higher IOPs and required more medications after subsequent cataract surgeries.

Aged↗

PubMed1995

Pars plana Baerveldt tube insertion with vitrectomy in glaucomas associated with pseudophakia and aphakia.

PURPOSE: We reviewed the course of intraocular pressure, visual acuity, and complications in patients with shallow anterior chambers or vitreous prolapse who underwent insertion of glaucoma drainage tubes through the pars plana (after a complete posterior vitrectomy). METHODS: Thirteen patients (13 eyes) with uncontrolled glaucoma associated with shallow anterior chamber or vitreous prolapse and aphakia or pseudophakia underwent pars plana Baerveldt tube insertion after vitrectomy. RESULTS: In 11 eyes the intraocular pressure was less than or equal to 15 mm Hg at a minimum follow-up of one year; the other two eyes underwent additional glaucoma surgery. Two of the 11 eyes with controlled intraocular pressure had limitation of ocular motility postoperatively. No retinal complications had occurred in any of the 13 eyes. CONCLUSION: This technique of combined pars plana vitrectomy and pars plana insertion of a Baerveldt tube provides intraocular pressure control in eyes with shallow anterior chamber or vitreous prolapse and glaucoma associated with pseudophakia or aphakia.

Adolescent↗

PubMed1995

Experience with the Baerveldt glaucoma implant in treating neovascular glaucoma.

PURPOSE: The authors present a retrospective study designed to assess the effectiveness of the Baerveldt glaucoma implant in controlling intraocular pressure (IOP) and maintaining visual function in eyes with neovascular glaucoma. METHODS: The medical records of all 36 patients (36 eyes) who underwent Baerveldt glaucoma implantation for medically uncontrolled neovascular glaucoma between February 1991 and December 1992 were reviewed. RESULTS: Eighteen patients received Model 350 implants, 16 received Model 500 implants, and 2 received Model 200 implants. The 12- and 18-month life-table success rates (success defined as 6 mmHg < or = final IOP < or = 21 mmHg without additional glaucoma surgery or devastating complication) were 79% and 56%, respectively. Visual acuity remained stable or improved in 10 (31%) patients. Postoperative complications included flat anterior chamber, serous choroidal detachment, and obstruction of the proximal tube tip with fibrovascular tissue, each of which occurred in four (11%) patients. Eleven (31%) patients lost light perception. There were no significant differences between the groups receiving the Model 350 and Model 500 implants with respect to life-table success rates, percentage of postoperative IOP reduction, or complication rates. Patients in the Model 500 implant group required significantly fewer antiglaucoma medications post-operatively, but also demonstrated a significantly greater mean visual acuity reduction. Better preoperative visual acuity and increased patient age were positively correlated with a successful outcome. CONCLUSIONS: Baerveldt implantation is effective in controlling IOP elevation associated with neovascular glaucoma. Postoperative visual loss, despite adequate IOP control, is common. Young patient age and poorer preoperative visual acuity are significant predictors of surgical failure.

Adult↗

PubMed1995

In vitro and in vivo flow characteristics of glaucoma drainage implants.

PURPOSE: To determine pressure-flow characteristics at physiologic flow rates in vitro and in vivo in rabbits for Ahmed, Baerveldt, Krupin disk, and OptiMed glaucoma implants. The Molteno dual-chamber implant also was evaluated in vivo only. METHODS: Five samples of each glaucoma implant were studied. Baerveldt implants were ligated partially for in vitro testing. Opening and closing pressures in air or after immersion in balanced salt solution or plasma were evaluated for the valved devices (Ahmed and Krupin). Pressures were measured in vitro and in vivo in normal rabbits at flow rates preset at between 2 and 25 microliters/minute after the tubes were connected to a closed manometric system. In vivo measurements were made 24 hours after implantation. Resistance to flow was calculated using Poiseuille's equation after at least three separate flow rate readings. RESULTS: In air, the Ahmed and Krupin valves had opening pressures of 9.2 +/- 3.4 and 7.2 +/- 0.6 mmHg and closing pressures of 5.2 +/- 0.9 and 3.9 +/- 1 mmHg, respectively. Neither opening nor closing pressures could be determined when Ahmed and Krupin valves were immersed. In vitro, the Ahmed and OptiMed devices had higher pressures than did other devices at a 2-microliters/minute flow rate of balanced salt solution. During perfusion with plasma, only the OptiMed device maintained higher pressures than with balanced salt. With all devices, pressures fell rapidly to zero after flow was stopped. The OptiMed device demonstrated the highest resistance values. In vivo, the Ahmed device provided pressures of 7.5 +/- 0.8 mmHg and the OptiMed device gave pressures of 19.6 +/- 5.6 mmHg at a 2-microliters/minute flow rate. After 15 minutes of flow shutdown, the OptiMed implant maintained pressures of 7.1 +/- 1.1 mmHg. The Baerveldt (nonligatured), Krupin, and Molteno dual-chamber implants had similar resistances and pressures in vivo. Pressures with all devices in vivo fell rapidly to zero after conjunctival wound disruption. CONCLUSION: Neither the Ahmed nor Krupin devices had demonstrable opening or closing pressures when tested in vitro immersed in balanced salt solution or plasma. With all devices, pressures were higher in vivo than in vitro due to tissue-induced resistance around the explant. Both Ahmed and Krupin valves functioned as flow-restricting devices at the flow rates studied, but did not close after initial perfusion with fluid.

Animals↗

PubMed1995

[Prostaglandins E2 and F2-alpha in uveitic glaucoma in the Lewis rat].

PURPOSE: In the preinflammatory phase of S-antigen (S-ag) induced uveitis, an ocular hypotension occurs between day 2 and day 6 after S-ag injection. To better understand this phenomenon, we studied the levels of prostaglandin E2 (PGE2) and prostaglandin F2-alpha (PGF2-alpha) in the aqueous humor of S-ag injected rats at various time points after induction of disease. METHODS: Twenty-five female Lewis rats weighting 150 to 175 gm were injected in the hind foot-pad with 50 micrograms of S-antigen. IOP was measured each day at 9 am with a Tono-Pen tonometer. Aqueous humor was collected at days 0, 2, 4, 6, 9, 14 and 18 after S-ag injection. PGE2 and PGF2-alpha were assayed in the aqueous humor using an enzyme immunoassay method. RESULTS: The concentration of PGE2 increased after day 6 and peaked at day 14 after S-ag injection (45.6 +/- 9.0 mu/ml vs 1.1 +/- 0.1 mu/ml in controls, P = 0.04). The peak of PGE2 corresponded to the maximum inflammation and ocular hypertension. PGF2-alpha was increased from day 2 to day 6, with a peak at day 6 after S-ag injection (128.0 +/- 51 pg/ml vs 56 +/- 2.0 pg/ml in controls, P = 0.047), which corresponded to the preinflammatory ocular hypotension. A second peak was observed at day 18 after S-ag injection (3643 +/- 824 pg/ml, P = 0.049), which corresponded to the cessation of intraocular inflammation and ocular hypertension. CONCLUSIONS: The early increased concentration of PGF2-alpha in the aqueous humor of rats with S-ag induced uveitis may explain the ocular hypotension observed from day 2 to day 6 after S-ag injection.

Animals↗

PubMed1995

Circadian rhythm of intraocular pressure: a rat model.

The purpose of this study was to examine whether there is a circadian rhythm of intraocular pressure (IOP) in the Lewis rat. Therefore, 20 Lewis rats (40 eyes) were subjected to an alternating 12-hour-light and 12-hour-dark cycle. Using a Tono-Pen 1, IOP was measured every 2 h between 6 a.m. and 12 midnight and every 3 h between 12 midnight and 6 a.m. for 2 consecutive days. These measurements in the Lewis rat revealed a reproducible circadian rhythm with a peak at 8 p.m. and a trough at 6 a.m. In conclusion, when using the Lewis rat as an animal model in longitudinal studies that involve the IOP, the IOP should be measured at the same time each day to correct for diurnal variations. Additionally, Lewis rats may be a useful model to study the causes of circadian rhythms of IOP and for pharmacologic studies of new glaucoma medications.

Animals↗

PubMed1995

Measurement of rabbit intraocular pressure with the Tono-Pen.

A Tono-Pen-1 (TP-1) and a Tono-Pen-2 (TP-2) were calibrated against direct manometry in the eyes of living rabbits to determine the accuracy of the Tono-Pen. Eighteen normal eyes of 10 rabbits were cannulated and connected to a pressure transducer with a chart recorder. Intraocular pressure (IOP) was increased from 5 to 40 mm Hg in 5-mm-Hg increments and from 40 to 80 mm Hg in 10-mm-Hg increments. After each incremental increase, IOP was measured first with a TP-1 and then with a TP-2. Plotting the mean Tono-Pen readings for each eye against the transducer pressure produced the following two regression line formulas: y = -0.613+0.790x (r2 = 0.97) for TP-1, and y = -1.45+0.824x (r2 = 0.97) for TP-2. Neither regression line was statistically different; p = 0.2 for the two slopes, and p = 0.24 for the y-axis intersection. The TP-1 and TP-2 can be used to rapidly and accurately measure the IOP in normal rabbit eyes. Tono-Pen readings do, however, significantly underestimate pressures in the range of 5-80 mm Hg. A table with 95% confidence intervals for corrected IOP readings obtained with the TP-1 or -2 is provided.

Animals↗

PubMed1994

Time parameters for glaucoma procedures.

Changes in physician reimbursement and the practice environment have emphasized the importance of determining physician time for procedures and services. Forty-five percent of the members of the American Glaucoma Society responded to a mail survey of estimates of the length of time and number of visits for the preoperative, operative, and 90-day postoperative care for six common glaucoma procedures. Results suggest a significant underestimation of time for trabeculectomies exists in the original and new resource-based relative value scale work values. Further, 47% to 53% of surgeons hospitalize patients on at least the first postoperative day. There were no apparent time efficiencies between "high-" and "low-volume" respondents. Thus, careful attention should be paid to the accuracy of certain time estimates and the resulting work values in the resource-based relative value scale. Additional work in this and other areas may prove illuminating.

Glaucoma↗

PubMed1994

Krupin disk implantation for complicated glaucomas.

BACKGROUND: The Krupin Eye Valve with Disk (Krupin disk) is a glaucoma shunt that incorporates a slit valve intended to minimize early postoperative hypotony. METHODS: The medical records of all patients who have undergone Krupin disk implantation at the Doheny Eye Institute between July 1990 and December 1992 (25 eyes of 25 patients) were reviewed. RESULTS: Intraocular pressure (IOP) was reduced from a mean of 36.1 +/- 11.5 mmHg to 15.3 +/- 7.5 mmHg at follow-up intervals of 4 to 19 months (mean, 13.2 months). On the first postoperative day, IOPs ranged from 0 to 40 mmHg. In two eyes (8%), the IOP was less than 6 mmHg, and in five eyes (20%) the IOP was more than 21 mmHg. Serous choroidal effusion and/or choroidal hemorrhage occurred in seven patients (28%). Six- and 12-month life-table success rates (6 < or = IOP < or = 21 mmHg) were 84% and 66%, respectively. CONCLUSION: The Krupin disk lowers IOP in most patients; however, the presence of a slit valve does not eliminate either early postoperative hypotony with its attendant complications or early IOP spikes.

Adolescent↗