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Biomedical subjects

M Bruce Shields

Publications and source records attributed to M Bruce Shields.

10 recordsLinked to original sources
PubMed2006

Factors associated with failure to follow up after glaucoma screening: a study in an African American population.

PURPOSE: To evaluate variables associated with failure to access free eye care after participating in glaucoma screening. DESIGN: Review of responses to a survey completed by participants during glaucoma screening. PARTICIPANTS: Two hundred seventy-three surveys completed by participants of African descent during screening. METHODS: African Americans 40 years or older participated in community glaucoma screening clinics, which included a survey with demographic and social variables. Each participant was given a preliminary diagnosis and encouraged to attend a free eye clinic for a complete examination. Survey results were correlated with attendance at the follow-up examination, using Student's t test, chi-square test, and logistic regression analysis. MAIN OUTCOME MEASURE: Noncompliance with follow-up after glaucoma screening. RESULTS: When adjusting for risk factors in logistic regression analysis, noncompliance was associated with living alone (P = 0.008), smoking (P = 0.0005), and lacking a car (P<0.01). Odds of noncompliance for participants living alone were 2.2 times higher than those for participants not living alone. Odds of noncompliance for participants who smoked were 3.0 times greater than those for participants who did not smoke. Odds of noncompliance for participants who did not have access to a car for their last eye examination were 2.1 times greater than those for participants who did. CONCLUSION: Socioeconomic factors such as smoking, lack of access to a car for eye examinations, and living alone are associated with noncompliance to follow-up after glaucoma screening clinics. Identifying persons with these variables may facilitate improved compliance.

Adult↗
PubMed2006

Glaucoma screening in a high-risk population.

PURPOSE: To evaluate a screening protocol for detection of individuals with a higher risk of chronic open angle glaucoma for which a complete glaucoma evaluation is indicated. PATIENTS AND METHODS: African Americans over 40 years of age in New Haven, CT. In the screening phase, volunteers filled out a questionnaire and underwent measurements of visual acuity, intraocular pressure (IOP) with a Tono-Pen and visual field with Frequency Doubling Technology. Participants were categorized into "glaucoma likely" or "unlikely," but all were encouraged to follow up with a free complete glaucoma exam, which included applanation tonometry, pachymetry, visual fields with a Humphrey Visual Field Analyzer, gonioscopy, and fundoscopy. Based on the latter exam, patients were categorized into "glaucoma likely" (suspects and confirmed glaucoma) or "unlikely" groups. RESULTS: One hundred eighty-four subjects completed both phases of the study and 76 of 93 patients (82%) who were classified as "glaucoma likely" in the final exam, were also classified as "glaucoma likely" in the screening. Adjusted analysis revealed family history of glaucoma in first degree relatives and screening IOP > 21 mm Hg to have statistically significant associations with the final impression of "glaucoma likely." A combination of these findings gave an overall sensitivity of 81.7% with a specificity of 55%. CONCLUSIONS: In the study population, the combination of an IOP > 21 mm Hg and history of glaucoma in a first degree relative allowed the identification of a significant percentage of individuals with a higher risk of chronic open angle glaucoma, for which a complete glaucoma examination is indicated.

Adult↗
PubMed2005

Needle revision of failed filtering blebs using 5-Fluorouracil and a combined ab-externo and ab-interno approach.

PURPOSE: To evaluate a surgical technique to revise a failed filtering bleb using subconjunctival 5-Fluorouracil with a combined ab-externo and ab-interno approach. PATIENTS AND METHODS: This study is a retrospective review of the outcome of 77 consecutive bleb revisions, with greater than 6-month follow-up, performed by a single glaucoma surgeon (MW). All eyes had previously functioning filtering blebs with currently inadequately controlled intraocular pressures (IOP) prior to the bleb revisions. All surgery was performed in the operating room, using a retrobulbar injection and a microscope. Visco-elastic was injected into the anterior chamber. 5-Fluorouracil (0.1 mL; 50 mg/ml) was infiltrated around the bleb. A 30-gauge needle was used to lyse subconjunctival fibrosis and episcleral scar tissue binding down the scleral flap, and elevate the scleral flap. Through an inferior paracentesis, a cyclodialysis spatula was used to confirm and enlarge the communication with the subconjunctival space. The main outcome measurements were IOP and number of glaucoma medications. A successful outcome was defined as a 20% reduction from baseline IOP and a maximum IOP of 18 mm Hg, with or without medications, and a minimal follow-up of 6 months. RESULTS: 52% of patients achieved success after one revision with an average follow-up of 29.6 +/- 14.4 months. In successful cases, the mean IOP decreased from 22.7 +/- 4.5 mm Hg to 11.3 +/- 3.5 mm Hg and medications were reduced from an average of 2.2 +/- 1.1 to 0.4 +/- 0.7. Kaplan-Meier survival analysis calculated a success of 77% at 1 year, 68% at 2 years, and 58% at 3 years. CONCLUSIONS: In failed filtering blebs, needle revision with 5-Fluorouracil and a combined ab-externo and ab-interno approach results in high success and low complication rates. The outcome of this procedure compares favorably with previously reported revision techniques.

Aged↗
PubMed2005

The influence of peripheral iridotomy on the intraocular pressure course in patients with pigmentary glaucoma.

PURPOSE: To evaluate the influence of laser peripheral iridotomy on the long-term intraocular pressure course for patients with pigmentary glaucoma. PATIENTS AND METHODS: Retrospective analysis of data contributed by members of the American Glaucoma Society on patients with bilateral pigmentary glaucoma, who received uniocular laser iridotomy. The main outcome measure was the post-laser intraocular pressure course of the treated eyes, compared with the fellow, untreated eyes. RESULTS: Sixty patients were included in the study, 46 of whom were observed for a minimum of 2 years (mean 70.3 +/- 26.0 months; range 24-113 months). Among the 14 patients who were observed for less than 2 years, the mean intraocular pressure in the treated eyes increased 0.36 +/- 2.63 mm Hg, compared with the fellow, untreated eyes. Among the 46 patients, observed for 2 years or more, the mean intraocular pressure in the treated eyes decreased 4.0 +/- 5.4 mm Hg, compared with 1.9 +/- 3.8 mm Hg in the fellow eyes (P = 0.005). However, analysis by linear models indicates that a higher mean baseline intraocular pressure in the treated eyes accounts for the apparent treatment effect of laser peripheral iridotomy. CONCLUSION: The study does not provide support for the benefit of laser peripheral iridotomy in the long-term intraocular pressure control of patients with pigmentary glaucoma, when the data are subjected to rigid statistical analysis. This does not disprove the benefit of laser iridotomy in this patient population, but underscores the need for a large, prospective study to address the question.

Adult↗
PubMed2004

Bleb revision for hypotony maculopathy after trabeculectomy.

PURPOSE: To assess the efficacy of a bleb revision technique with regard to improvement in intraocular pressure (IOP) and visual acuity after hypotony maculopathy and to evaluate the influence of duration of hypotony on visual outcome. PATIENTS AND METHOD: : Retrospective review of a series of patients who underwent bleb revision for hypotony maculopathy (IOP less than 6 mm Hg and loss of two or more lines of central vision) following trabeculectomy. Bleb revision included excision of avascular bleb tissue, dissection posteriorly between conjunctiva and Tenon's capsule, and advancement and suturing of the conjunctiva at the limbus. RESULTS: Fourteen patients were included in the study. The average age was 49.8 years (range 18-85) and eight were female. Before trabeculectomy, the mean IOP was 23.2 +/- 11.8 mm Hg, and the visual acuity was 20/30-2 or better in 13 patients and 20/80 in one patient. The mean IOP before bleb revision was 1.07 +/- 0.73 mm Hg, and 12 patients had lost an average of 4.33 +/- 2.96 lines of visual acuity from baseline, while one had count fingers and another had hand motion vision. The final mean IOP after bleb revision was 11.07 +/- 3.08 mm Hg. Compared with visual acuity just prior to bleb revision, 12 patients regained an average best corrected vision of 3.08 +/- 2.67 lines, with seven returning to the pre-trabeculectomy vision level. The duration of hypotony prior to bleb revision was 1 to 24 months (average 8.36 months) with no correlation (correlation coefficient -0.13) between duration and visual outcome. CONCLUSION: Bleb revision for hypotony maculopathy following trabeculectomy is an effective technique for raising IOP and limiting visual loss, which is not influenced by duration of hypotony within the time frame of the study.

Adolescent↗
PubMed2004

Characterization and prevalence of PITX2 microdeletions and mutations in Axenfeld-Rieger malformations.

PURPOSE: Mutations of the homeodomain protein PITX2 produce Axenfeld-Rieger (AR) malformations of the anterior chamber, an autosomal dominant disorder accompanied by a 50% risk of glaucoma. Twenty-nine mutations of PITX2 have been described, with a mutational prevalence estimated between 10% and 60% in AR. In the current study, the possible role of altered PITX2 gene dosage in the etiology of AR was investigated. Gross gene deletions and duplications should alter PITX2 activity analogously to hypomorphic and hypermorphic mutations, respectively. METHODS: Sixty-four patients with AR, iridogoniodysgenesis (IGD), iris hypoplasia (IH), or anterior segment dysgenesis (ASD) were screened for PITX2 mutations by sequencing. PITX2 gene dosage was concurrently examined in these patients by real-time quantitative PCR. Microsatellite markers were used to map 4q25 microdeletions at a contig scale, as well as for haplotype analysis in an extended AR kindred. An additional 27 patients with other assorted ocular phenotypes were evaluated by similar methods, amounting to a total of 91 cases analyzed. RESULTS: Three novel mutations of PITX2 (4.7%) were identified among 64 patients with AR, IGD, IH, or ASD. Deletions of PITX2 were as frequent as mutations in our sample. Chromosome 4q25 microdeletions were physically mapped relative to several microsatellite markers in each patient. Cosegregation of AR and a PITX2 deletion was demonstrated in an extended kindred. CONCLUSIONS: Point mutations and gross deletions of PITX2 appear to produce an equivalent haploinsufficiency phenotype. Quantitative PCR is an efficient means of detecting causative PITX2 deletions in patients with AR and may increase the detection rate at this locus.

Anterior Eye Segment↗
PubMed2002

Effect of mild to moderate myopic correction by laser-assisted in situ keratomileusis on intraocular pressure measurements with goldmann applanation tonometer, tono-pen, and pneumatonometer.

PURPOSE: To evaluate the effect of mild to moderate myopic correction by laser-assisted in situ keratomileusis (LASIK) on intraocular pressure (IOP) measurements with three tonometers: the Goldmann applanation tonometer, Tono-Pen, and pneumatonometer. PATIENTS AND METHODS: In a prospective study of a clinic-based population undergoing elective LASIK surgery for myopia correction, IOP measurements were obtained preoperatively and postoperatively with a Goldmann applanation tonometer, Tono-Pen, and pneumatonometer. Central corneal thickness and keratometric and astigmatism measurements were also obtained before and after surgery. A paired test was used to evaluate the significance of differences between preoperative and postoperative IOP measurements with each instrument. Linear regression was used to correlate IOP measurements with degree of myopia corrected, astigmatism, and central corneal thickness before and after surgery. RESULTS: The study included 66 eyes of 34 individuals with a mean preoperative refractive error of -5.66 + 2.3 D (mean + SD). The reduction of central corneal thickness after LASIK of 0.032 + 0.030 mm (mean + SD) was statistically significant ( < 0.0001). However, there was no statistically significant change in mean IOP after the procedure with the Goldmann applanation tonometer or the Tono-Pen, while the pneumatonometer, was associated with a small but statistically significant decrease in mean IOP of 1.1 mm Hg. CONCLUSION: In this group of patients with mild to moderate myopia, LASIK had little or no statistically significant influence on IOP readings obtained with a Goldmann applanation tonometer, Tono-Pen, or pneumatonometer. This finding is in contrast to earlier reports of greater amounts of myopic correction, in which significant reductions in measured IOP were observed. Further study is needed to determine whether a critical amount of corneal change after LASIK is required to have a significant effect on IOP measurements.

Adult↗
PubMedDate not supplied

Considerations of glaucoma in patients undergoing corneal refractive surgery.

Glaucoma patients present a unique set of challenges to physicians performing corneal refractive surgery. Corneal thickness, which is modified during corneal refractive surgery, plays an important role in monitoring glaucoma patients because of its effect on the measured intraocular pressure. Patients undergo a transient but significant rise in intraocular pressure during the laser-assisted in situ keratomileusis (LASIK) procedure with risk of further optic nerve damage or retinal vein occlusion. Glaucoma patients with filtering blebs are also at risk of damage to the bleb by the suction ring. Steroids, typically used after refractive surgery, can increase intraocular pressure in steroid responders, which is more prevalent among glaucoma patients. Flap interface fluid after LASIK, causing an artificially low pressure reading and masking an elevated pressure has been reported. The refractive surgeon's awareness of these potential complications and challenges will better prepare them for proper management of glaucoma patients who request corneal refractive surgery.

Cornea↗
PubMedDate not supplied

Iridocorneal endothelial syndrome in a child.

The iridocorneal endothelial syndrome is an important and unusual cause of acquired glaucoma in adults. We report its occurrence in a child who presented with glaucoma. The patient required glaucoma surgery, and a goniotomy and trabeculectomy were performed. The patient's clinical findings and the results of surgeries are described.

Child↗