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Biomedical subjects

Y M Buys

Publications and source records attributed to Y M Buys.

16 recordsLinked to original sources
PubMed2004

Prospective study comparing lidocaine 2% jelly versus sub-Tenon's anaesthesia for trabeculectomy surgery.

AIMS: To compare the analgesic properties of lidocaine 2% jelly versus sub-Tenon's anaesthesia with lidocaine 2% without adrenaline (epinephrine) for trabeculectomy surgery. METHODS: A prospective randomised clinical trial. 59 consecutive patients scheduled for trabeculectomy at the Toronto Western Hospital were randomly assigned to topical unpreserved lidocaine 2% jelly or sub-Tenon's anaesthesia with 2% lidocaine. Both groups received a standardised sedative consisting of midazolam, fentanyl. and/or propofol. The visual analogue scale was utilised to measure intraoperative pain. Patient comfort, physician assessment of intraoperative patient compliance, volume of local anaesthetic used, need for supplemental anaesthesia, and any complications were recorded. The two groups were compared using the Student's t test. RESULTS: The sub-Tenon's anaesthesia group and the lidocaine 2% jelly group did not vary significantly in subjective pain score (18.3 (SD 16.2) v 19.8 (12.4) respectively, p = 0.739) and surgeons' satisfaction scale (3.6 (0.7) and 3.8 (0.6) respectively, p = 0.328). Four patients required additional anaesthesia, all of them in the sub-Tenon's group. CONCLUSION: Topical lidocaine 2% jelly is as effective as sub-Tenon's anaesthesia for pain control in patients undergoing trabeculectomy. Lidocaine 2% jelly is similar to sub-Tenon's anaesthesia in patient comfort and surgeon satisfaction.

Aged↗
PubMed2000

Long-term results of transscleral Nd:YAG cyclophotocoagulation for refractory glaucoma postpenetrating keratoplasty.

PURPOSE: To determine the effects of noncontact transscleral Nd:YAG cyclophotocoagulation (NCTY) in the treatment of refractory glaucoma postpenetrating keratoplasty (PKP) with respect to intraocular pressure (IOP), corneal graft survival, and reduction of glaucoma medications. METHODS: The records of all patients treated with NCTY for refractory glaucoma after PKP at the authors' institution over an 11-year interval were reviewed. The LASAG noncontact Nd:YAG laser (Lasag AG; Thun, Switzerland) was used. Approximately 40 laser applications were delivered per eye. Visual acuity, IOP, glaucoma medications, and corneal graft clarity were evaluated. RESULTS: Fifty-two eyes met the inclusion criterion. The mean pretreatment IOP was 38.7+/-11.9 mm Hg. The mean posttreatment IOP was 15.8+/-9.7 mm Hg. From life table analysis, the probability of having a posttreatment IOP of 21 mm Hg or less with or without medication was 70% at 1 year and 63% at 5 years. The probability of a graft remaining clear was 79% at 1 year and 56% at 5 years. In 85% of patients the visual acuity remained stable, in 11% the visual acuity improved, and in 4% the visual acuity deteriorated after treatment. One patient developed hypotony. Twenty patients (36.5%) were able to discontinue one or more glaucoma medications posttreatment. CONCLUSION: In this group of patients with PKP glaucoma, NCTY effectively lowered IOP over the long term, with 36.5% of patients discontinuing one or more glaucoma medications. There was, however, a significant incidence of graft failure at 5 years.

Adult↗
PubMed1999

Ultrasound biomicroscopic quantitative analysis of light-dark changes associated with pupillary block.

PURPOSE: To quantitatively analyze the changes in anterior chamber angle and iris configuration induced by varying illumination in patients with narrow angles and pupillary block. METHODS: Twenty-four eyes of 24 patients with pupillary block (mean age, 52.5 years) had ultrasound biomicroscopic images of the angle and iris structures obtained superiorly, nasally, inferiorly, and temporally. Images were performed in the light and the dark. We measured the angle opening distance, iris thickness, iris chord length, iris-lens touch, and iris curvature. RESULTS: Changes in iris and angle configuration occurred within a few seconds of a change in lighting. The mean dark measurements were statistically significantly less than the mean light measurements for angle opening distance (96 +/- 18 vs 185 +/- 26 microm, P = .0001), iris chord length (2,505 +/- 61 vs 3,001 +/- 69 microm, P = .0001), and iris-lens touch (350 +/- 20 vs 693 +/- 35 microm, P = .0001). The mean dark measurements were statistically significantly greater than the mean light measurements for iris thickness at 500 microm from the scleral spur (367 +/- 10 vs 307 +/- 25 microm, P = .0001), and 1,500 microm from the scleral spur (404 +/- 14 vs 347 +/- 12 microm, P = .0001). Iris curvature in all four quadrants was statistically significantly greater in the dark than the light. CONCLUSIONS: This study quantitatively confirms that angle narrowing in the dark in eyes with pupillary block is associated with iris shortening, increased iris thickness, and increased iris convexity. Iris-lens touch is relatively small in pupillary block and decreases with dilation. Angle narrowing with dilation is not related to increased iris-lens touch and occurs promptly without requiring time for aqueous pressure buildup behind the iris.

Adult↗
PubMed1999

Retinitis pigmentosa, nanophthalmos, and optic disc drusen: a case report.

OBJECTIVE: Although the associations of retinitis pigmentosa (RP) with nanophthalmos/microphthalmos and RP with optic disc drusen have previously been recognized, the concurrence of all three features, as far as the authors are aware, has not previously been reported. DESIGN: Case report. RESULTS: The authors report a sporadic case of nanophthalmos, RP, and optic nerve drusen with the additional complication of chronic angle closure glaucoma. CONCLUSIONS: Visual loss may be secondary to the complications of nanophthalmos, RP, or optic nerve drusen. Chronic angle closure may be caused by choroidal effusion with serous retinal detachment, which may, in turn, cause a pseudo-RP picture. It is therefore important to recognize the possible association of true RP with nanophthalmos as a cause for visual deterioration.

Aged↗
PubMed1999

Efficacy of brimonidine 0.2% as adjunctive therapy for patients with glaucoma inadequately controlled with otherwise maximal medical therapy.

PURPOSE: To evaluate the clinical efficacy and tolerability of brimonidine tartrate 0.2% twice daily as adjunctive therapy for glaucoma patients inadequately controlled with otherwise maximal tolerated medical therapy. DESIGN: Retrospective, noncomparative, case series. PARTICIPANTS: Ninety-six patients were identified from the authors' tertiary glaucoma practice who were treated with brimonidine. Their glaucoma was uncontrolled despite maximal tolerated medical therapy before receiving brimonidine, and some had previously undergone argon laser trabeculoplasty or filtration surgery. The patients were subdivided according to their glaucoma diagnosis: open-angle (OAG), angle-closure (ACG), mixed mechanism, and congenital glaucoma. Both the short- (about 2 weeks) and long-term results were evaluated. Twenty-two patients were excluded because additional medication changes were made at the time of introduction of brimonidine. INTERVENTION: Brimonidine was added to the existing regimen of glaucoma medication. MAIN OUTCOME MEASURES: Intraocular pressure (IOP) was recorded at all follow-up dates, together with visual field examination and optic disc evaluation twice yearly. RESULTS: There were 44 OAG, 20 ACG, 6 mixed mechanism, and 4 congenital glaucoma patients. Mean pretreatment IOP, mean short-term post-treatment IOP, and mean short-term IOP reduction (percentage) were 23.10 +/- 5.21 mmHg, 18.49 +/- 4.77 mmHg, and 4.6 mmHg (20%) for OAG; 22.80 +/- 5.70 mmHg, 18.65 +/- 5.75 mmHg, and 4.15 mmHg (18%) for ACG; 25.00 +/- 10.32 mmHg, 21.00 +/- 12.12 mmHg, and 4.0 mmHg (16%) for mixed mechanism; and 26.00 +/- 4.97 mmHg, 17.75 +/- 4.57 mmHg, and 8.25 mmHg (32%) for congenital glaucoma, respectively. Mean long-term follow-up was 204 days for OAG and 213 days for ACG. Of the initially controlled OAG and ACG patients, at 3 months 96% and 100%, at 6 months 80% and 77%, and at 9 months 58% and 44%, respectively, were still controlled. Six patients discontinued brimonidine, three of these owing to allergy. CONCLUSION: As adjunctive therapy, brimonidine achieved a short-term IOP reduction of 16%-32% in this patient population; 77%-80% of initially controlled patients were still controlled after 6 months. Brimonidine was well tolerated.

Adolescent↗
PubMed1999

Analysis of myocilin mutations in 1703 glaucoma patients from five different populations.

A glaucoma locus, GLC1A, was identified previously on chromosome 1q. A gene within this locus (encoding the protein myocilin) subsequently was shown to harbor mutations in 2-4% of primary open angle glaucoma patients. A total of 1703 patients was screened from five different populations representing three racial groups. There were 1284 patients from primarily Caucasian populations in Iowa (727), Australia (390) and Canada (167). A group of 312 African American patients was from New York City and 107 Asian patients from Japan. Overall, 61 different myocilin sequence variations were identified. Of the 61 variations, 21 were judged to be probable disease-causing mutations. The number of probands found to harbor such mutations in each population was: Iowa 31/727 (4.3%), African Americans from New York City 8/312 (2.6%), Japan 3/107 (2.8%), Canada 5/167 (3.0%), Australia 11/390 (2.8%) and overall 58/1703 (3. 4%). Overall, 16 (76%) of 21 mutations were found in only one population. The most common mutation observed, Gln368Stop, was found in 27/1703 (1.6%) glaucoma probands and was found at least once in all groups except the Japanese. Studies of genetic markers flanking the myocilin gene suggest that most cases of the Gln368Stop mutations are descended from a common founder. Although the specific mutations found in each of the five populations were different, the overall frequency of myocilin mutations was similar ( approximately 2-4%) in all populations, suggesting that the increased rate of glaucoma in African Americans is not due to a higher prevalence of myocilin mutations.

Asian People↗
PubMed1999

Is a tight patch necessary after trabeculectomy?

AIMS: To determine if post-trabeculectomy patching reduces the prevalence of shallow/flat anterior chambers and pain. METHODS: 435 eyes were prospectively randomised to either a double patch with tape or no patch with tape group. RESULTS: There was no statistically significant difference in flat or shallow anterior chamber rates or pain symptoms between the patch and no patch groups. CONCLUSION: There is no benefit to patching the post-trabeculectomy eye.

Anterior Chamber↗
PubMed1999

Agreement in assessing glaucomatous discs in a clinical teaching setting with stereoscopic disc photographs, planimetry, and laser scanning tomography.

PURPOSE: Agreement between three observers--two recently trained fellows and their supervisor--was measured using estimations of cup/disc ratio from stereoscopic optic nerve head photographs and planimetric measurements of cup/disc ratio. Agreement between the clinicians' planimetric measurements of cup/disc ratio and laser scanning tomographic measurements of cup/disc ratio also was assessed. METHODS: From 16 stereoscopic optic nerve head photographs of 16 subjects, the three observers performed clinical estimations of horizontal and vertical cup/disc ratios and planimetric measurements of cup/disc ratios. Interobserver agreement was measured using intraclass correlation coefficients (ICCs). Agreement between the planimetric cup/disc ratios and laser scanning tomographic cup/disc ratios obtained with the Heidelberg Retina Tomograph (HRT; Heidelberg Engineering, Heidelberg, Germany) also was measured using ICCs. The difference between the planimetric and HRT cup/disc ratios was calculated. RESULTS: The agreement between observers for clinical estimations from stereoscopic optic nerve head photographs (ICC = 0.74 horizontally and 0.83 vertically) was substantial. Agreement between the observers' planimetric measurements of cup/disc ratio was substantial (ICC = 0.79). Agreement between HRT cup/disc ratio and each observer's planimetric cup/disc ratio was moderate (ICC = 0.57-0.65), with large confidence intervals. The cup/disc ratio measured with HRT was an average of 0.07 to 0.11 larger than the planimetric cup/disc ratio. CONCLUSION: Substantial agreement between observers can be achieved when estimating cup/disc ratio with stereoscopic optic nerve head photographs and with planimetric measurements of cup/disc ratios, provided there is a standard protocol and sufficient training period. Good agreement is critical in a teaching institution to ensure accurate follow-up care of patients with glaucoma, especially if patients are examined by different clinicians. Laser scanning tomography is a more repeatable and objective method, which may provide further standardization of optic nerve head assessments. Future studies will determine the reference plane that optimizes agreement between the HRT findings and each clinician's estimations.

Confidence Intervals↗
PubMed1999

Interobserver agreement of Heidelberg retina tomograph parameters.

PURPOSE: To measure the interobserver agreement of Heidelberg Retina Tomograph (HRT; Heidelberg Engineering, Heidelberg, Germany) parameters as a result of different observers' contour line placement. METHODS: The optic nerve heads of 50 patients with glaucoma were imaged with the HRT. Five observers traced each disc margin with a contour line. Each observer was masked to the contour line tracings of the other observers, and there was no formal discussion as to where to place the contour line. The following stereometric parameters were calculated for each image for each observer: disc area, mean height of contour, cup shape, rim volume using the standard reference plane from software version 1.11, rim volume using a reference plane of 320 microns below the retinal plane, and volume above curved surface. Agreement between the five observers was tested for each parameter using intraclass correlation coefficients (ICCs). RESULTS: Interobserver agreement between the five observers was substantial for both rim volumes (ICC = 0.73) and for disc area (ICC = 0.67). Agreement was almost perfect for mean height of contour (ICC = 0.94), cup shape (ICC = 0.92), and volume above curved surface (ICC = 0.83). CONCLUSION: The interobserver agreement for the HRT parameters was substantial to almost perfect, indicating that the HRT results as defined by the five observers were interchangeable.

Glaucoma, Open-Angle↗
PubMed1998

Imaging zonular abnormalities using ultrasound biomicroscopy.

OBJECTIVES: To evaluate the use of ultrasound biomicroscopy (UBM) in detecting ciliary zonular defects and to describe the UBM signs of such defects. METHODS: Eighteen eyes of 18 patients with clinically suspected zonular abnormalities were evaluated using UBM. Predisposing factors included pseudoexfoliation, congenital spherophakia, surgical procedure, trauma, and the Marfan syndrome. RESULTS: Of 18 eyes, 11 showed UBM evidence of missing zonules and 11 showed evidence of zonular stretch. Four of the 18 eyes had both missing and stretched zonular fibers. All of the eyes examined showed increased lenticular sphericity in the area of zonular disorder. Nine eyes showed ciliary body flattening. Pupillary block was seen in 5 patients, and angle crowding due to direct iridal rotation was noted in 3. CONCLUSIONS: Ultrasound biomicroscopy can detect zonular loss and stretching directly. Increased lenticular sphericity and ciliary body flattening are signs of zonular defects. Angle closure mechanisms include pupillary block and direct iridal rotation.

Adolescent↗
PubMed1995

(-)-Deprenyl increases the survival of rat retinal ganglion cells after optic nerve crush.

Retinal ganglion cells (RGCs) have been shown to die by apoptosis after damage to their axons caused by optic nerve crush and the death can be reduced by some neurotrophic factors. Since (-)-deprenyl can reduce apoptotic death in some neuronal systems, we determined whether it can increase RGC survival after optic nerve crush. Fluoro-Gold (FG), a fluorescent retrograde tracer, was injected into both superior colliculi to pre-label RGC cells bodies in the retinal ganglion cell layers (RGCLs) of adult Sprague-Dawley rats. Fours days later, the left optic nerve was crushed immediately behind the globe and the animals received either (-)-deprenyl (1 mg/kg) or saline by intraperitoneal injection every two days for 14 days. Nissl stained neuronal cell bodies per mm of section length of RGCL were counted from serial frozen sections. The number of RGCL cell bodies sending axons to the superior colliculi (RGCSCS) were identified by FG fluorescence as a means of determining the proportion of RGCL neurons (RGCLns) that were RGCSCS. In the uncrushed retinas an average of 40.7% of the RGCLns were found to be RGCSCS. There was no difference in RGCSCS/mm between the uncrushed treated with saline group and the uncrushed group treated with (-)-deprenyl group. The optic nerve crush with saline group showed a decrease in RGCSCS to 3.0 +/- 1.0% of the uncrushed saline group while the optic nerve crush with (-)-deprenyl group showed a considerably smaller decrease in RGCSCS to 36.9 +/- 11.2% of the uncrushed saline group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Prospective study of sub-Tenon's versus retrobulbar anesthesia for inpatient and day-surgery trabeculectomy.

PURPOSE: Several retrospective studies have demonstrated the safety and efficacy of sub-Tenon's anesthesia in ocular surgery. This is the first prospective randomized study comparing sub-Tenon's versus retrobulbar anesthesia for glaucoma surgery. METHODS: Thirty-nine patients undergoing both inpatient and day surgery trabeculectomy were randomized to receive retrobulbar or sub-Tenon's anesthesia. Retrobulbar anesthesia consisted of a 1.5-ml injection of a 1:1 mixture of 2% lidocaine without epinephrine and 0.5% plain bupivacaine with hyaluronidase. Sub-Tenon's anesthesia consisted of 2% lidocaine without epinephrine injected over the superior, medial and lateral recti muscles. Both groups received a van Lint lid block and a standardized sedative. Outcome parameters evaluated included patient demographics, operative complications, intraoperative and postoperative patient comfort, and volume of anesthetic. RESULTS: Seventeen patients were randomized to the retrobulbar group and 22 to the sub-Tenon's group. Patient discomfort was statistically similar between the groups. There was no statistical difference between groups with respect to quantity of sedative received, surgical exposure, eye movements, or operative complications. A retrobulbar hemorrhage, however, developed at the time of retrobulbar anesthesia in one patient, requiring cancellation of surgery. A larger volume of local anesthetic was required in the retrobulbar group versus the sub-Tenon's group (1.8 versus 1.1 ml; P < 0.01). Patients receiving retrobulbar injections were more likely to require additional anesthesia (P < 0.01) and postoperative analgesics (P < 0.05) compared with patients undergoing sub-Tenon's injection. There was no significant difference between the groups with respect to age, sex, or operated eye. CONCLUSIONS: Sub-Tenon's anesthesia is safe and effective for patients undergoing either inpatient or day-surgery trabeculectomies, and it requires less local anesthetic than retrobulbar anesthesia.

Ambulatory Surgical Procedures↗
PubMed1992

Retinal findings after head trauma in infants and young children.

BACKGROUND: Many authorities believe that the finding of retinal hemorrhages in a child younger than 3 years of age with a history of head trauma, in the absence of an obvious cause for the injury, is pathognomonic of child abuse. To date, no studies have examined the prospective retinal examination of children who have had head trauma. The authors undertook such a study because the presence of retinal hemorrhage from any head trauma in children may have medicolegal diagnostic significance in differentiating accidental from nonaccidental trauma. METHODS: Seventy-nine children younger than 3 years of age, each of whom experienced head injury, underwent an ophthalmologic assessment, which included a dilated funduscopic examination. RESULTS: Seventy-five children sustained accidental head injuries and had normal funduscopic examinations. Three children had nonaccidental head injuries and all were found to have varying degrees of retinal hemorrhages. One child, with a normal fundus examination, had injuries that were of indeterminate cause. CONCLUSION: The finding of retinal hemorrhages in a child with a head injury suggests a nonaccidental cause.

Battered Child Syndrome↗