Biomedical subjects

M B Sherwood

Publications and source records attributed to M B Sherwood.

At least 19 recordsLinked to original sources

PubMed2004

A new model of glaucoma filtering surgery in the rat.

PURPOSE: The most common reason for long-term failure of glaucoma filtering surgery (GFS) is scarring of the external filtering "bleb" tissues. The identification of the factors that mediate this process, as well as the development and initial testing of new therapies to limit scarring is enhanced by the use of appropriate animal models. The standard animal model for studying GFS is the rabbit but newer investigative tools that examine changes induced in biologic systems at a genetic level have made development of a rat model desirable. METHODS: Glaucoma filtering surgery was performed on 20 Sprague-Dawley rats by introducing a 30-gauge silicone cannula through a penetrating scleral tunnel, under a limbal-based conjunctival flap and suturing the conjunctiva closed. Identical GFS was performed on 3 additional rats, which underwent histologic evaluation at days 2, 5, and 11, following surgery.Fistulizing surgery was also performed on 6 Sprague-Dawley rats, for comparison, by creating a full-thickness needle sclerostomy under a limbal-based conjunctival flap and suturing the conjunctiva closed. RESULTS: Following the cannula GFS, well-elevated filtering blebs formed and these gradually failed over the course of 8 to 13 days. Needle tract sclerostomy filtering blebs formed at the site of the fistulizing surgery but rapidly failed over the course of 2 to 3 days. CONCLUSION: Cannulated filtering surgery in the rat provides a longer lasting and more predictable model than needle tract sclerostomy for studying wound healing following GFS and may facilitate the study of induced changes at the gene level.

Animals↗

PubMed2003

Corneal thickness and endothelial cell density measured by non-contact specular microscopy and pachymetry in Rhesus macaques (Macaca mulatta) with laser-induced ocular hypertension.

PURPOSE: Sustained increase in intraocular pressure (IOP) in humans results in a loss of corneal endothelial cells and an increase of corneal thickness. The effects of chronically elevated IOP on the corneal endothelium of monkeys with laser-induced ocular hypertension, a commonly used animal model of human glaucoma have not been documented. This study examined the central corneal thickness (CCT), the corneal endothelial cell density (ECD), and the corneal endothelial cell size (ACS) in Rhesus monkeys with experimental ocular hypertension. Materials and methods. Ten male monkeys with argon laser-induced ocular hypertension in one eye for an average duration of 2.4+/-0.7 years, were sedated with ketamine hydrochloride, and the CCT, ECD, and ACS measured at the center of the cornea of both eyes with a Topcon SP-2000P non-contact specular microscope (Topcon America Corporation((R)), Paramus, NJ, USA). CCT was also measured using a DHG-500 Pachette ultrasonic pachymeter (DHG Technology Inc., Exton, PA, USA). Mean and standard deviation (S.D.) of CCT, ECD and ACS for each eye was calculated and statistically compared.Results. Mean CCT in the hypertensive and normal eyes measured by specular microscopy was 0.477+/-0.023mm and 0.468+/-0.020 mm, respectively. Mean ECD in the hypertensive and normal eyes was 2601.7+/-631.8 and 3990.2+/-402.9 cells mm(-2), respectively. The mean size of the endothelial cells was 252.4+/-23.9 micro m(2) in the normal eye and 408.7+/-115.0 microm m(2) in the hypertensive eye. No significant difference in the measurement of CCT was observed between the specular microscope and the pachymeter (p=0.46). No significant difference in the mean CCT was observed between the two eyes (p=0.4820), whereas the mean ECD was significantly lower in the hypertensive eye than in the normal eye (p<0.001). The ECD was inversely related to the length of IOP elevation (p<0.001). CONCLUSIONS: No difference in the corneal thickness measurement was observed between the specular microscopy and the pachymetry techniques. Chronic ocular hypertension did not significantly affect the CCT, but caused a significant loss of endothelial cells in the center of the cornea of the laser treated eyes compared to the normotensive eyes. The duration of elevated IOP was the most important factor affecting the ECD.

Animals↗

PubMed2000

Enhanced short-term plasmid transfection of filtration surgery tissues.

PURPOSE: To quantify and localize plasmid transfection of filtration surgery tissues using two delivery techniques. METHODS: Full-thickness filtering procedures were performed on eyes of New Zealand albino rabbits. In 10 eyes, naked plasmid DNA in saline was either injected beneath Tenon's capsule at the filtration site or absorbed into a collagen shield that was then placed external to the sclerostomy and under the Tenon's capsule. Forty-eight hours after surgery, levels of the reporter gene, chloramphenicol acetyltransferase (CAT) were measured in samples of ocular tissues. In two additional eyes, the ss-galactosidase (ss-GAL:) reporter gene expression was localized histologically. RESULTS: Injection of plasmid DNA in saline vehicle into the filtration bleb produced readily detectable CAT activity in bleb tissue (conjunctiva, Tenon's capsule, and sclera) whereas CAT activity was nearly undetectable in samples of the cornea, iris-ciliary body, and tissues located opposite the bleb site. Delivery of the plasmid DNA into the bleb through a collagen shield increased CAT activity 30-fold over injection of plasmid in saline (2711 +/- 567 mU/mg versus 92 +/- 38 mU/mg). ss-Gal activity was imaged only in the region of the bleb, and microscopic examination showed ss-Gal activity localized to Tenon's capsule fibroblasts, with minimal ss-Gal activity observed in inflammatory cells or scleral fibroblasts. CONCLUSIONS: Transfection of filtration tissues is enhanced by absorption of naked DNA into a collagen shield. Furthermore, transfection is localized to the fibroblasts and inflammatory cells of the filtration bleb site. Gene therapy using naked plasmid DNA and a simple collagen shield delivery vehicle may be useful for regulating wound healing after glaucoma surgery.

Animals↗

PubMed1999

Mid-peripheral pattern electrical retinal responses in normals, glaucoma suspects, and glaucoma patients.

AIMS: Reliance on intraocular pressure, optic nerve cupping changes, nerve fibre layer integrity, and visual field changes may delay treatment of glaucoma since irreversible changes may have already occurred at the time of diagnosis. Abnormal pattern electrical retinal responses (PERR or PERG) have been demonstrated in patients with ocular hypertension (no visual field changes) and glaucoma when visual stimulation was presented to the central field. Since glaucomatous visual field changes tend to occur first in the mid-periphery, the use of PERR outside of the central field may offer an earlier indication of glaucomatous involvement. METHODS: Glaucoma suspects and glaucoma patients were derived from a university practice. Normal subjects were recruited from non-patient volunteers. Alternating bar gratings were presented in the supranasal, supratemporal, infratemporal, and infranasal visual field. Six spatial frequencies, from 0.25 to 6.0 cycles per degree, were used for normal volunteers; three spatial frequencies, from 0.38 to 1.5 cycles per degree, were presented to suspects and glaucoma patients. Time of onset of the first negative (N35) and first positive peak (P50) and the amplitude consisting of the absolute difference between the first negative peak and first positive peak (P50 amplitude) are reported. Age corrected values were determined for normals, suspects, and glaucoma patients for each spatial frequency and for each quadrant in the visual field. RESULTS: Mean P50 amplitudes from normal subjects showed spatial tuning in all quadrants with reduced low frequency attenuation. Normals demonstrated a small decline in amplitude with age. Glaucoma patients demonstrated an age corrected reduction in amplitude and early implicit times. Glaucoma suspects had values between those of normal and glaucoma subjects. P50 amplitudes were weakly correlated with increasing cup to disc diameter ratio. A glaucoma patient with asymmetric visual field loss demonstrated significant diminution of the PERR bilaterally. CONCLUSION: The PERR, using mid-peripheral stimulation, may be a sensitive tool for the early detection of glaucoma. Further refinements can speed clinical data acquisition and enhance signal to noise ratio.

Adolescent↗

PubMed1999

A randomized trial of the effect of midazolam on intraocular pressure.

PURPOSE: The effect of midazolam on intraocular pressure (IOP) in adults was studied as an initial step in determining whether it can be used as a preoperative anxiolytic or sedative agent in children with glaucoma who are undergoing examination for IOP measurements. METHODS: This study followed a prospective, placebo controlled, randomized, double masked design. Fifty-five participants were enrolled after informed consent was obtained. Each enrolled patient underwent a brief history and eye examination. Measurements of IOP were taken at baseline and 5, 10, and 15 minutes after intravenous administration of 1 mg midazolam or placebo. IOP was the primary outcome measured. RESULTS: There was no difference in IOP fluctuation from baseline between patients who received midazolam and those who received placebo. CONCLUSION: Early results indicate that because midazolam does not lower IOP, it may be a useful adjunct to ketamine anesthesia in children with glaucoma undergoing ophthalmologic examination under anesthesia. However, studies of midazolam must be conducted in children and patients with glaucoma before its use in these populations can be recommended.

Anesthesia, Intravenous↗

PubMed1998

Glaucoma's impact on quality of life and its relation to clinical indicators. A pilot study.

OBJECTIVE: This study aimed to compare the quality of life (Q of L) of patients with glaucoma and control subjects and to determine the relationships between Q of L and demographic and clinical variables in patients with glaucoma. DESIGN: The study design was a stratified cross-sectional study. PARTICIPANTS: A gender-, race-, and age-stratified cross-sectional sample of patients with glaucoma (n = 56) and control subjects (n = 54) was obtained. Additional patients (n = 12) were included to examine the relationships between glaucoma, its therapy, and Q of L. INTERVENTION: The Medical Outcomes Study short form (MOS-20), the Activities of Daily Vision Scale (ADVS), and questions related to glaucoma and side effects of treatment were administered. Descriptive statistics characterized demographic variables and MOS and ADVS scales. Group differences were evaluated using chi-square, Fisher's and Ordinal Exact, Wilcoxon rank-sum, and two-sample t tests. Spearman rank correlations were obtained between MOS-ADVS scores and clinical and demographic variables. Regression was used for multivariate analysis. MAIN OUTCOME MEASURES: The MOS scores, ADVS scores, visual acuity, visual fields, and demographic variables were measured. RESULTS: Patients scored significantly lower than did the control subjects in all MOS-20 categories except pain. Differences were physical (-20%), role (-43%), mental health (-10%), general health (-22%), and social (-9%). The only category that was not statistically significant was that of pain (P = 0.075). In the glaucoma subgroup, there were differences between whites and nonwhites in MOS subscales physical, role, social, pain, and health, and ADVS near vision. In patients, current medications and previous surgeries correlated with ADVS subscales night vision, near vision, and glare; visual acuity and fields correlated with MOS subscales physical, role and health, and all ADVS subscales. A multiple regression model including visual acuity and fields, urban residence, and female gender explained 61% of the variability in ADVS overall score. CONCLUSIONS: The Q-of-L perception differed between patients with glaucoma and control subjects. Increasing field loss, decreased visual acuity, and complexity of therapy correlated with patients' reduction in activities of daily vision.

Activities of Daily Living↗

PubMed1998

Diurnal intraocular pressure curves in healthy rhesus macaques (Macaca mulatta) and rhesus macaques with normotensive and hypertensive primary open-angle glaucoma.

PURPOSE: The authors identify any diurnal intraocular pressure (IOP) variation in healthy Cayo Santiago macaques, as well as Cayo Santiago macaques with normotensive and hypertensive primary open-angle glaucoma (POAG), to further evaluate their potential value as a model for human POAG. METHODS: Twenty-four monkeys (eight animals each of the healthy control, normotensive glaucoma, and hypertensive glaucoma groups) were sedated with ketamine hydrochloride and the IOP measured hourly from 8:00 AM until 3:00 PM with a Tonopen XL applanation tonometer (Mentor, Norwell, MA, U.S.A.). Mean IOP time profiles, mean IOPs at each observation time, and linear trends in mean IOP over time were compared among groups. Intraocular pressure rate-of-change over time and residual variation about the regression line for each individual eye were analyzed. Cup/disc ratio (C/D) was compared with baseline IOP, IOP profile mean and slope, and IOP residual variation. RESULTS: A significant group and time effect on mean IOP (p = 0.0001 and 0.011, respectively), with highest values at 2:00 PM or 3:00 PM, and a significant increasing linear trend in mean IOP over time in the hypertensive group were observed (p = 0.012). Intermediate readings between control and hypertensive mean IOPs were identified for the normotensive glaucoma group. The biggest range of IOP variation was found in the hypertensive glaucoma monkeys. Higher variations in IOP did not lead to an increase in C/D. CONCLUSIONS: This study provides evidence that the Cayo Santiago macaques are a valuable model for human normotensive and hypertensive POAG.

Animals↗

PubMed1998

Change in intraocular pressure during long-term use of loteprednol etabonate.

PURPOSE: Loteprednol etabonate is a novel site-active corticosteroid synthesized through structural modifications of prednisolone-related compounds so that it will undergo a predictable transformation to an inactive metabolite. In double-masked studies, loteprednol etabonate was effective in the treatment of giant papillary conjunctivitis, seasonal allergic conjunctivitis, postoperative inflammation, and uveitis. The objective of this analysis was to determine the incidence of clinically significant elevations in intraocular pressure (IOP) with long-term use of loteprednol etabonate. PATIENTS AND METHODS: All subjects (healthy volunteers or patients with inflammation or allergy) in all sponsored loteprednol etabonate studies in the United States were evaluated. A clinically significant elevation in IOP was defined as > or = 10 mmHg at any visit, and long-term use was defined as > or = 28 days. Of the 2,210 subjects, 1,648 were treated for 28 days or longer with loteprednol etabonate (0.2% or 0.5%), prednisolone acetate 1%, or vehicle. RESULTS: IOP elevation > or = 10 mmHg occurred in 1.7% (15/901) of patients taking long-term loteprednol etabonate, 0.5% (3/583) of those taking vehicle, and 6.7% (11/164) of those taking prednisolone acetate. Excluding patients who wore contact lenses, the incidence was 0.6% (4/624), 1.0% (3/304), and 6.7% (11/164) for loteprednol etabonate, vehicle, and prednisolone acetate, respectively. The incidence of IOP elevations with 0.2% loteprednol etabonate was 0.8% (1/133), similar to that for vehicle (0.7%, 1/135). CONCLUSION: The results of this analysis in a large population of subjects undergoing long-term therapy and of a previously published controlled, double-masked study in corticosteroid responders suggest that loteprednol etabonate has less propensity to cause clinically significant elevations in IOP than prednisolone acetate.

Androstadienes↗

PubMed1998

Signs of glaucoma in rhesus monkeys from a restricted gene pool.

PURPOSE: To investigate the distribution of intraocular pressure (IOP) and cup properties in a colony of rhesus monkeys that has had no outside genetic input since 1938 (approximately 12 generations). This sample of sequestered monkeys is significantly larger than any previously reported. Comparisons are made with a sample of random-source monkeys to develop population estimates defining the limits of normalcy. METHODS: The IOP and cup/disc ratio estimates were collected from 701 eyes of 354 adult rhesus monkeys from the closed colony on Cayo Santiago, Puerto Rico. Results for IOP were compared with the normal rhesus IOP population distribution function calculated from an earlier sample of genetically heterogeneous rhesus. RESULTS: The mean +/- standard deviation IOP in the Cayo Santiago monkeys (15.8+/-3 mmHg) related well to the calculated "normal" rhesus distribution (14.5+/-2 mmHg) below and around the mean IOP only. Above the mean rhesus IOP, the samples from the Cayo monkeys were strongly skewed: 129 eyes had IOP more than two standard deviations above the normal mean IOP, and 54 eyes had IOP more than three standard deviations above the normal mean IOP. Cup/disc ratio estimations tended to cluster as higher values in the higher IOP quartiles. Some eyes with IOP below the mean had cup/disc ratios > 0.5. Values for IOP that were more than two standard deviations above the mean and cup/disc ratios > 0.4 were not uniformly distributed across social groupings, although incidence of high IOP was more than 25% in one group. CONCLUSION: After 12 generations with the same genetic pool, expression of ocular hypertension and large optic disc cups is high but not uniform.

Animals↗

PubMed1997

Results of intraoperative 5-fluorouracil or lower dose mitomycin-C administration on initial trabeculectomy surgery.

PURPOSE: This study was conducted to review outcomes in eyes following primary trabeculectomy supplemented intraoperatively with 5-fluorouracil (5-FU) or lower dose mitomycin-C (MMC). PATIENTS AND METHODS: We retrospectively reviewed the medical records of 73 eyes of 63 patients with progressive, far advanced open angle glaucoma who had undergone initial trabeculectomy with intraoperative application of 5-FU, 50 mg/mL for 5 min (N = 37), or MMC, 200 micrograms/mL for 3-5 min (N = 36), and with at least 12 months follow-up. RESULTS: Mean preoperative intraocular pressures (IOPs) in the MMC and 5-FU groups were 24.3 +/- 7.6 and 24.6 +/- 9.3 mm Hg, respectively. Postoperatively, IOPs were similar at 6-month interval follow-up examinations in the MMC and 5-FU groups. At an average follow-up of 20.9 months, mean final visit postoperative IOPs were 10.2 +/- 3.6 (p < 0.001) and 9.7 +/- 3.4 mm Hg (p < 0.001) in the MMC and 5-FU groups, respectively, requiring an average of 0.25 and 0.22 antiglaucoma medications per eye, respectively. Interval follow-up complications were similar between groups and included four bleb leaks in the MMC group, and three bleb leaks in the 5-FU group. Visual acuity remained stable in 71 of 73 eyes. CONCLUSIONS: Both antifibrosis agents provide good intermediate term IOP control and may be appropriate for use in those eyes requiring final "target" IOPs in the low teens or single digits.

Adult↗

PubMed1997

Treatment of bleb leaks with transforming growth factor-beta in the rabbit model.

PURPOSE: The mechanism through which peribleb injection of autologous blood results in resolution of bleb leak in the rabbit model remains unclear. This study evaluates the clinical and histologic effects of peribleb injection of transforming growth factor-beta (TGF-beta) after leak induction in mitomycin-C-treated blebs. METHOD: Posterior lip sclerectomies treated with mitomycin-C were created in New Zealand White rabbits. On postoperative day 7, a standardized stab incision was performed on all blebs, and the eyes were randomized to receive a peribleb injection of either TGF-beta or of a balanced salt solution. RESULTS: Injection of TGF-beta was associated with the resolution of bleb leak and maintenance of a functioning bleb in 50% (4 of 8) of treated eyes. The remaining TGF-beta-treated eyes and control eyes demonstrated continued bleb leaks or bleb failures with intraocular pressure returning to preoperative levels. Histologic examination revealed increased peribleb cellularity and denser collagen deposition in the TGF-beta-treated eyes compared with that observed in control eyes. CONCLUSIONS: Peribleb TGF-beta injections may contribute to healing bleb leaks, but the injections do not appear in this model to be as useful as whole-blood injections.

Animals↗

PubMed1996

Injection of autologous blood for bleb leaks in New Zealand white rabbits.

PURPOSE: Bleb leaks after trabeculectomy with antimetabolites can be recalcitrant to therapy. Peribleb autologous blood injections are a moderately successful new treatment modality for such leaks. However, it is unclear what mechanism the injections work to achieve leak resolution. METHODS: A randomized, prospective study in the rabbit model was undertaken to evaluate further the clinical and histologic effects of peribleb autologous blood injection after leak induction in mitomycin-C exposed blebs, compared to controls that received only peribleb balanced salt solution injections. RESULTS: In the blood-treated eyes, all bleb leaks healed. Control eyes either demonstrated persistent bleb leaks with shallow anterior chambers or failed blebs that were Seidel negative. Histologic results were remarkable for increased peribleb cellularity and collagen deposition in the blood-treated eyes, compared to controls. CONCLUSIONS: Peribleb autologous blood injections are associated with bleb leak resolution, increased peribleb cellularity, and collagen deposition in the rabbit model.

Animals↗

PubMed1996

Neovascular glaucoma after carotid endarterectomy.

The authors examined a patient who had neovascular glaucoma (NVG) shortly after ipsilateral carotid endarterectomy and followed the patient's clinical course. The authors speculate that the sudden reperfusion after endarterectomy that occurs in patients with combined central retinal artery occlusion and carotid occlusive disease may enhance the circulation of preformed angiogenesis factors, leading to the development of neovascularization. The authors recommend frequent and careful surveillance of patients with central retinal artery occlusion associated with carotid occlusive disease if ipsilateral carotid endarterectomy is performed.

Aged↗

PubMed1995

Comparison of the Baerveldt glaucoma implant with the double-plate Molteno drainage implant.

OBJECTIVE: To compare the 350-mm2 Baerveldt implant with the double-plate Molteno implant in the treatment of eyes with complicated glaucoma. DESIGN: Retrospective chart review of a consecutive series of drainage implants. SETTING: University-based referral practice. PATIENTS: Thirty-four consecutive patients (37 eyes) undergoing glaucoma drainage device implantation because of uncontrolled, complicated glaucoma. INTERVENTION: Eighteen eyes underwent 350-mm2 Baerveldt implantation and 19 eyes underwent double-plate Molteno implantation. MAIN OUTCOME MEASURES: Intraocular pressure (IOP) control, visual acuity outcome, and complication rate. RESULTS: Mean preoperative IOP was 30.2 mm Hg in the Baerveldt group, with an average of 2.7 antiglaucoma medications, and 28.4 mm Hg in the Molteno group, with an average of 2.4 antiglaucoma medications. With an average follow-up of 11.3 months (range, 5 to 16 months), mean IOP at the final visit was 13.1 mm Hg (range, 7 to 21 mm Hg) in the Baerveldt group, with an average of 1.3 medications, and 13.4 mm Hg (range, 8 to 25 mm Hg) in the Molteno group, with an average of 0.8 medications. Final IOP was between 7 and 19 mm Hg in 16 of 18 Baerveldt eyes and in 17 of 19 Molteno eyes. Visual acuity (when it could be checked) remained stable (+/- 2 Snellen lines) in 17 of 17 eyes in the Baerveldt group and in 17 of 19 eyes in the Molteno group. Complications in the Baerveldt group included two cases (11%) of flat anterior chamber after stent removal, one case (6%) of intermittently symptomatic diplopia, and one case (6%) of endophthalmitis. In the Molteno group there were two graft failures (11%) and one eye (5%) with loss of central field. CONCLUSIONS: Both types of drainage implants provide excellent postoperative IOP control. Early stent removal should be avoided if possible in eyes with Baerveldt implants.

Anterior Chamber↗

PubMed1994

Activation and suppression of fibroblast function.

The fibroblast is the central player in the wound repair and scarring processes that occur in the anterior segment of the eye. Glaucoma filtration surgery is the ultimate example of the importance of the wound healing process, as this process is the major determinant of the success of this procedure. We highlight the role of the fibroblast, and discuss some of the growth factors stimulating fibroblast proliferation, migration and extracellular matrix production in the wound environment. We also review current methods of suppressing fibroblast proliferation, the new concepts that have arisen from laboratory studies, and future directions of investigation and treatment.

Animals↗

PubMed1993

Prolonged localized tissue effects from 5-minute exposures to fluorouracil and mitomycin C.

Rabbits undergoing full-thickness glaucoma filtering surgery were exposed for 5 minutes to one of three intraoperative treatments: (1) distilled water; (2) fluorouracil, 50 mg/mL; or (3) mitomycin C, 0.4 mg/mL. Tissue samples were taken from the subconjunctival and scleral tissues at the treated area and 90 degrees and 180 degrees from the center of the treated area and the adjacent cornea 2 mm from the limbus, 1 hour, 5 days, and 30 days postoperatively. The biopsy specimens were then placed in tissue culture media and the fibroblast outgrowths measured. Five-minute intraoperative treatments with fluorouracil resulted in a reversible delay of fibroblast outgrowths from treated subconjunctival and scleral tissues of just over 1 week in this model, whereas treatment with mitomycin C, 0.4 mg/mL, resulted in prolonged inhibition of at least 30 days. These effects were localized to the area treated. The many clinical implications of these findings are discussed.

Animals↗

PubMed1993

Effects of intraoperative 5-fluorouracil or mitomycin C on glaucoma filtration surgery in the rabbit.

PURPOSE: To establish the effects of single intraoperative exposures to either 5-fluorouracil (5-FU) or two different concentrations of mitomycin C (MMC) on filtration surgery in the rabbit. METHODS: A prospective, randomized, masked-observer, placebo-controlled study was performed to compare the effects on filtration surgery in rabbits of a single 5-minute intraoperative exposure to 5-FU (50 mg/ml), MMC (0.2 mg/ml), or MMC (0.4 mg/ml) with control eyes treated with distilled water. RESULTS: Intraocular pressures (IOPs) remained lower for longer and bleb survival was increased (P < 0.05) with all three treatments compared with control eyes. The effect of 5-FU was more transient than MMC. Bleb survival was prolonged in the following order: MMC 0.4 > MMC 0.2 > 5-FU 50 mg/ml. At 30 days, blebs were present in 100% of eyes treated with MMC 0.4 mg/ml, 60% of eyes treated with MMC 0.2 mg/ml, and 0% of eyes treated with 5-FU 50 mg/ml or distilled water. The blebs in the eyes treated with MMC were thinner, and significant complications (endophthalmitis, transient corneal opacification and neovascularization, and a presumed bleb leak) only occurred in the eyes treated with MMC 0.4 mg/ml. CONCLUSIONS: The authors' results suggest that 5-FU and MMC at these concentrations, delivered as a single intraoperative dose, prolong the survival of filtration surgery for different lengths of time in the rabbit, which is a model that normally exhibits aggressive healing and rapid failure of filtration surgery. The implications of these potentially titratable effects for filtration surgery in different categories of patients are discussed.

Animals↗

PubMed1993

Prevention of early hypotony associated with Molteno implants by a new occluding stent technique.

BACKGROUND: A major complication of unvalved drainage tube implants is hypotony. Occluding stents to internally block the tube, but which lie exposed in the inferior fornix, have been described. The authors report modifications of this technique. METHODS: A nonexposed 3-0 Supramid suture is used to internally block the tube, with the end placed subconjunctivally. Small venting slits are made in the extrascleral portion of the tube to provide early control of intraocular pressure. Molteno implants were placed in 32 eyes of 29 patients using these modifications. RESULTS: Mean preoperative intraocular pressure was 30.3 mmHg on an average of 2.6 medications. The stent was pulled without difficulty in the office treatment room a mean of 26 days postoperatively. Intraocular pressure from postoperative day 2 until the day of stent removal ranged from 2 to 26 mmHg, with 72% of eyes having intraocular pressure between 5 and 19 mmHg. There were 3 (9.4%) minor complications in the 32 eyes, with 1 case of early anterior chamber shallowing and 2 cases of moderate choroidal detachments, which settled spontaneously. With an average follow-up of 10.2 months, mean intraocular pressure at the final visit was 13.4 mmHg on an average of 1 medication. CONCLUSION: The "occluding stent" described here can be a helpful adjunct to unvalved drainage tube surgery in preventing early postoperative hypotony.

Adolescent↗