PubMed Health⌕ Search

Biomedical subjects

Richard K Parrish

Publications and source records attributed to Richard K Parrish.

At least 19 recordsLinked to original sources
PubMed2006

Detection and prognostic significance of optic disc hemorrhages during the Ocular Hypertension Treatment Study.

PURPOSE: To compare the rates of detection of optic disc hemorrhages by clinical examination and by review of optic disc photographs at the Optic Disc Reading Center (ODRC), to assess the incidence of and the predictive factors for disc hemorrhages in the annual disc photographs of the Ocular Hypertension Treatment Study (OHTS), and to determine whether optic disc hemorrhages predict the development of primary open-angle glaucoma (POAG) in the OHTS. DESIGN: Cohort study. PARTICIPANTS: Three thousand two hundred thirty-six eyes of 1618 participants. METHODS: Both eyes of participants were examined for optic disc hemorrhages every 6 months by clinical examination, with dilated fundus examinations every 12 months, and by annual review of stereoscopic disc photographs at the ODRC. MAIN OUTCOME MEASURES: Incidence of optic disc hemorrhages and POAG end points. RESULTS: Median follow-up was 96.3 months. Stereophotography-confirmed glaucomatous optic disc hemorrhages were detected in 128 eyes of 123 participants before the POAG end point. Twenty-one cases (16%) were detected by both clinical examination and review of photographs, and 107 cases (84%) were detected only by review of photographs (P<0.0001). Baseline factors associated with disc hemorrhages were older age, thinner corneas, larger vertical cup-to-disc ratio, larger pattern standard deviation index on perimetry, family history of glaucoma, and smoking status. The occurrence of a disc hemorrhage increased the risk of developing POAG 6-fold in a univariate analysis (P<0.001; 95% confidence interval, 3.6-10.1) and 3.7-fold in a multivariate analysis that included baseline factors predictive of POAG (P<0.001; 95% confidence interval, 2.1-6.6). The 96-month cumulative incidence of POAG in the eyes without optic disc hemorrhage was 5.2%, compared with 13.6% in the eyes with optic disc hemorrhage. In eyes with a disc hemorrhage in which a POAG end point developed, the median time between the 2 events was 13 months. CONCLUSIONS: Review of stereophotographs was more sensitive at detecting optic disc hemorrhage than clinical examination. The occurrence of an optic disc hemorrhage was associated with an increased risk of developing a POAG end point in participants in the OHTS. However, most eyes (86.7%) in which a disc hemorrhage developed have not experienced a POAG end point to date.

Cohort Studies↗
PubMed2006

The association between glaucomatous visual fields and optic nerve head features in the Ocular Hypertension Treatment Study.

PURPOSE: To determine the association between change from baseline in the optic nerve head (ONH) and the visual field (VF) during follow-up of ocular hypertension participants in the Ocular Hypertension Treatment Study. DESIGN: Longitudinal randomized clinical trial. PARTICIPANTS: One hundred sixty-eight eyes of 152 ocular hypertensive participants ages 40 to 80 years. METHODS: Cox hazard models were applied to 3232 eyes, which included 81 eyes that reached a study end point by developing a glaucomatous VF (VF end point) and 128 eyes that reached a study end point by developing an optic disc change (optic disc end point). MAIN OUTCOME MEASURES: Primary open-angle glaucoma end point as determined by changes in the VF or optic disc. RESULTS: Forty-one eyes reached an end point by both VF and optic disc criteria; 40 eyes reached only a VF end point, and 87 reached only an optic disc end point. Times to reach isolated disc or field end points were similar. Visual field end points were more likely (P<0.0001) in eyes that showed the following ONH features: an ONH hemorrhage, thinning of the optic disc rim, or enlargement of the horizontal cup-to-disc (C/D) ratio. Optic disc end points were more likely (P<0.0001) in eyes that showed the following VF features: some evidence of a nasal step or a partial arcuate VF defect, or an increase in the pattern standard deviation (PSD). CONCLUSIONS: Both the VF and the optic disc must be monitored with equal diligence, because either may show the first evidence of glaucomatous damage. Changes in the ONH based on stereophotographic observation (rim thinning, hemorrhage, or a slight increase in C/D ratio) and VF changes (evidence of a nasal step/partial arcuate defect or an increase in PSD) suggest that these cases have an increased risk of developing glaucoma. Confirmation of such subtle findings should be sought through repeat testing and correlation with other clinical results.

Adult↗
PubMed2006

Retinal nerve fiber layer analysis in the diagnosis of glaucoma.

PURPOSE OF REVIEW: The detection of optic disc and retinal nerve fiber layer damage and change is the cornerstone of glaucoma management. Assessment of the retinal nerve fiber layer for localized and diffuse damage has been traditionally based on clinical examination, with documentation of change primarily qualitative. With the latest improvements in optical imaging instruments, objective and quantitative measurements of the retinal nerve fiber layer are now possible. This review summarizes the results from recent cross-sectional studies evaluating the discriminating ability of automated retinal nerve fiber layer measurements to detect glaucoma, and from longitudinal studies assessing the ability to predict and monitor glaucomatous changes. RECENT FINDINGS: Numerous cross-sectional studies have documented good diagnostic accuracy of a scanning laser polarimeter (GDx VCC), the optical coherence tomograph (Stratus), and the Heidelberg Retina Tomograph retinal nerve fiber layer measurements for differentiating between healthy and glaucoma eyes. There are only limited data available on the ability of these retinal nerve fiber layer measurements to document change over time. SUMMARY: It is essential that the clinician understand the specific strengths and weaknesses of each technique so that only good quality retinal nerve fiber layer information will be used in conjunction with careful clinical examination and visual function testing for glaucoma management decisions. Longitudinal studies are needed to evaluate the ability of these instruments to document retinal nerve fiber layer change over time.

Diagnostic Imaging↗
PubMed2005

The tube versus trabeculectomy study: design and baseline characteristics of study patients.

PURPOSE: The Tube Versus Trabeculectomy (TVT) Study will compare the safety and efficacy of nonvalved tube shunt surgery to trabeculectomy with mitomycin C in patients with previous intraocular surgery. DESIGN: Multicenter randomized clinical trial. METHODS SETTING: 17 Clinical Centers. STUDY POPULATION: Patients 18 to 85 years of age who have undergone previous trabeculectomy, cataract extraction with intraocular lens implantation, or both and have inadequately controlled glaucoma with intraocular pressure (IOP) >or=18 mm Hg and <or=40 mm Hg on tolerated medical therapy. INTERVENTIONS: Study patients were randomized to undergo placement of a 350-mm(2) Baerveldt glaucoma implant or trabeculectomy with mitomycin C (0.4 mg/ml for 4 minutes). MAIN OUTCOME MEASURES: IOP, complication rates, visual acuity, visual field, quality of life, reoperations for glaucoma, and need for supplemental medical therapy. RESULTS: A total of 212 patients were enrolled between October 1999 and April 2004. The age of the study population was 71.0 +/- 10.4 years (mean +/- SD), and 53% were women. The baseline IOP was 25.3 +/- 5.3 mm Hg (mean +/- SD). There were no significant differences in the demographic and ocular characteristics between the 2 treatment groups. CONCLUSIONS: Practice patterns vary in the surgical management of glaucoma, and there are differing opinions among glaucoma surgeons regarding the preferred surgical approach in patients who have undergone previous cataract extraction and/or failed filtering surgery. Forthcoming data from the TVT Study should provide valuable information comparing two surgical procedures commonly used in this patient population.

Adult↗
PubMed2005

Test-retest reproducibility of optic disk deterioration detected from stereophotographs by masked graders.

PURPOSE: To assess the reproducibility of determining whether an eye has developed optic disk deterioration by the Optic Disc Reading Center (ODRC) in the Ocular Hypertension Treatment Study (OHTS). DESIGN: Test-retest reproducibility study. METHODS: Masked, certified graders at the ODRC determine the occurrence of optic disk deterioration in OHTS by comparing baseline with follow-up stereoscopic optic disk photographs. To assess reproducibility, re-gradings were obtained annually by inserting masked "quality control" photographs into the usual ODRC reading stream. RESULTS: Agreement (kappa) ranged from 0.65 to 0.83 over 5 years. Specificity ranged from 98% to 100%, and sensitivity ranged from 64% to 81%. CONCLUSIONS: The kappa statistic for test-retest agreement in OHTS is in the range considered good to excellent over 5 years. Consistency (specificity) in re-grading optic disks that did not develop deterioration was particularly high. The sensitivity results show that detecting subtle deterioration of optic disks is challenging.

Glaucoma, Open-Angle↗
PubMed2005

Pattern electroretinogram abnormality and glaucoma.

PURPOSE: To determine the existence of retinal ganglion cell dysfunction and associated risk factors in glaucoma suspects with increased optic disc cupping and normal visual field. DESIGN: Cross-sectional, observational study. PARTICIPANTS: Two hundred glaucoma suspect (GS) patients were identified based on optic disc abnormalities (vertical cup-to-disc ratios [C/D]>0.5; vertical C/D asymmetry >or= 0.2; disc hemorrhages; notching) in association with known glaucoma risk factors (positive family history, African American descent, increased intraocular pressure [IOP]), but normal visual fields. Forty-two patients had early manifest glaucoma (EMG). Sixteen normal black subjects were added to update previous pattern electroretinogram (PERG) normative data and to establish a normal control (NC) group with a racial breakdown comparable with that of the study groups. METHODS: Pattern electroretinograms were recorded simultaneously from both eyes using skin electrodes and automated analysis; visual fields were monitored with standard white-on-white automated perimetry (SAP) central 24-2 program; vertical C/D was evaluated by an independent reader from stereo disc photographs; and univariate and multivariate statistical analysis between PERG and other outcome measures was evaluated. MAIN OUTCOME MEASURES: Pattern electroretinogram amplitude (microV), phase (pi rad), and interocular asymmetry in amplitude and phase (%); and SAP mean deviation (MD; decibels), vertical C/D, age (years), IOP (mmHg), and race (black vs. nonblack). RESULTS: The PERG results were abnormal in at least 1 of the outcome measures in 52% of GS patients and 69% of EMG patients. The PERG amplitude was correlated weakly with both MD (P<0.01) and vertical C/D (P = 0.05). The correlation between PERG amplitude and MD and C/D was stronger (P<0.001) for interocular differences rather than absolute measures. Interocular PERG amplitude asymmetry increased with severity of disease (EMG>GS>NC; P<0.01). The PERG amplitude decline with age was steeper in patients with a more negative MD (P<0.01) and in patients with a more negative MD and a larger vertical C/D (P = 0.06). Black race (but not family history) was associated with lower PERG amplitude (P = 0.005) in GS and EMG patients, but not in normal controls (P = 0.44). CONCLUSIONS: The correlation between PERG abnormality and known risk factors for glaucoma indicates that PERG has a predictive potential for the development or progression of the disease, or both.

Adult↗
PubMed2005

2002 survey of the American Glaucoma Society: practice preferences for glaucoma surgery and antifibrotic use.

PURPOSE: To determine the preference of members of the American Glaucoma Society for the use of antifibrotic agents (mitomycin C or 5-fluorouracil or both) and glaucoma drainage devices in ten clinical settings. MATERIALS AND METHODS: Voluntary written survey of the American Glaucoma Society. RESULTS: American Glaucoma Society (AGS) members continue to report preference for mitomycin C use in ten clinical settings. The percent usage for glaucoma drainage devices has increased in poor prognosis scenarios including the following: neovascular glaucoma, previous failed trabeculectomy, previous ECCE/ICCE, previous PKP, previous scleral buckling surgery, and uveitic glaucoma. However, trabeculectomy and MMC continue to be more likely employed for surgical management. CONCLUSION: Despite the long-term complications of bleb-related infections, no statistically significant shift in preference away from MMC use or reduction in the concentration of drug delivery was observed since the 1996 survey.

Antineoplastic Agents↗
PubMed2003

Use of glaucoma drainage devices in the management of glaucoma associated with aniridia.

PURPOSE: To describe intraocular pressure (IOP) and visual acuity outcomes after glaucoma drainage device placement in eyes with glaucoma associated with aniridia. DESIGN: Retrospective, noncomparative, consecutive, interventional case series. METHODS: The medical records of all patients who underwent glaucoma drainage device placement for the management of glaucoma associated with aniridia at the Bascom Palmer Eye Institute between January 1, 1989, and December 31, 1999, were reviewed. RESULTS: The study included eight eyes of five patients with a median age at the time of glaucoma drainage device placement of 92 months (range, 10- 495 months) and a median follow-up of 19 months (range, 11- 33 months). Preoperatively, the mean IOP was 35 mm Hg using a mean of one antiglaucoma medication. Postoperatively, the mean IOP was reduced to 14.9 mm Hg and no patient was using antiglaucoma medication. Final visual acuity was improved compared with preoperatively in five of eight eyes (63%) and remained unchanged in two eyes (25%). Loss of light perception occurred in one eye owing to retinal detachment. Success rates using Kaplan-Meier survival analysis were 100% at 6 months and 88% at 1 year. CONCLUSIONS: Glaucoma drainage device placement for glaucoma associated with aniridia achieves IOP control and vision preservation in most patients.

Adolescent↗
PubMed2003

A comparison of latanoprost, bimatoprost, and travoprost in patients with elevated intraocular pressure: a 12-week, randomized, masked-evaluator multicenter study.

PURPOSE: To Internet Advance publication at ajo.com Feb 13, 2003. compare the intraocular pressure (IOP)-lowering effect and safety of latanoprost, bimatoprost, and travoprost in patients with open-angle glaucoma (OAG) or ocular hypertension (OH). DESIGN: Interventional study. METHODS: This 12-week, randomized, parallel-group study was conducted at 45 US sites. Previously treated patients with OAG or OH and an IOP > or =23 mm Hg in one or both eyes after washout received either latanoprost 0.005%, bimatoprost 0.03%, or travoprost 0.004% once daily in the evening. At baseline and after 6 and 12 weeks of therapy, masked evaluators measured IOP in triplicate at 8:00 AM, 12 noon, 4:00 PM, and 8:00 PM, and masked investigators graded conjunctival hyperemia before the 8:00 AM IOP measurement. The primary efficacy outcome measure was change between baseline and Week 12 in the 8:00 AM IOP (time of peak drug effect). RESULTS: In all, 410 of 411 randomized patients were included in intent-to-treat analyses (latanoprost, 136; bimatoprost, 136; travoprost, 138). Baseline mean 8:00 AM IOP levels were similar (P =.772); by week 12, reductions were observed in all 3 groups (P <.001 for each). Adjusted (ANCOVA) reductions in mean IOP at 8:00 AM were similar (P =.128) as were those at 12 noon, 4:00 PM, and 8:00 PM. Fewer latanoprost-treated patients reported ocular adverse events (P <.001, latanoprost vs bimatoprost), fewer reported hyperemia (P =.001, latanoprost vs bimatoprost), and average hyperemia scores were lower at week 12 (P =.001, latanoprost vs bimatoprost). CONCLUSIONS: Latanoprost, bimatoprost, and travoprost were comparable in their ability to reduce IOP in OAG and OH patients. Latanoprost exhibited greater ocular tolerability.

Adult↗
PubMed2003

Uveal melanoma presenting as acute angle-closure glaucoma: report of two cases.

PURPOSE: To present two cases of uveal melanoma presenting as acute angle-closure glaucoma. DESIGN: Observational case reports. Assessment and management of two patients with uveal melanoma presenting with acute angle-closure glaucoma. RESULTS: One patient was initially treated with antiglaucoma medications, and a laser peripheral iridotomy was performed. The second patient had opaque media preventing visualization of the posterior segment, but the presence of an occult mass was suspected as the cause of angle closure. In both cases, B-scan ultrasonography revealed the presence of a tumor causing angle-closure glaucoma. The eyes were enucleated, and the diagnosis of uveal malignant melanoma was confirmed by histopathology. CONCLUSION: Although acute angle-closure as the initial presentation of uveal melanoma is rare, the presence of a uveal melanoma should be suspected in eyes unresponsive to medical therapy, especially in unilateral cases in which the view of the posterior segment is obscured.

Acute Disease↗
PubMed2002

The Ocular Hypertension Treatment Study: a randomized trial determines that topical ocular hypotensive medication delays or prevents the onset of primary open-angle glaucoma.

BACKGROUND: Primary open-angle glaucoma (POAG) is one of the leading causes of blindness in the United States and worldwide. Three to 6 million people in the United States are at increased risk for developing POAG because of elevated intraocular pressure (IOP), or ocular hypertension. There is no consensus on the efficacy of medical treatment in delaying or preventing the onset of POAG in individuals with elevated IOP. Therefore, we designed a randomized clinical trial, the Ocular Hypertension Treatment Study. OBJECTIVE: To determine the safety and efficacy of topical ocular hypotensive medication in delaying or preventing the onset of POAG. METHODS: A total of 1636 participants with no evidence of glaucomatous damage, aged 40 to 80 years, and with an IOP between 24 mm Hg and 32 mm Hg in one eye and between 21 mm Hg and 32 mm Hg in the other eye were randomized to either observation or treatment with commercially available topical ocular hypotensive medication. The goal in the medication group was to reduce the IOP by 20% or more and to reach an IOP of 24 mm Hg or less. MAIN OUTCOME MEASURES: The primary outcome was the development of reproducible visual field abnormality or reproducible optic disc deterioration attributed to POAG. Abnormalities were determined by masked certified readers at the reading centers, and attribution to POAG was decided by the masked Endpoint Committee. RESULTS: During the course of the study, the mean +/- SD reduction in IOP in the medication group was 22.5% +/- 9.9%. The IOP declined by 4.0% +/- 11.6% in the observation group. At 60 months, the cumulative probability of developing POAG was 4.4% in the medication group and 9.5% in the observation group (hazard ratio, 0.40; 95% confidence interval, 0.27-0.59; P<.0001). There was little evidence of increased systemic or ocular risk associated with ocular hypotensive medication. CONCLUSIONS: Topical ocular hypotensive medication was effective in delaying or preventing the onset of POAG in individuals with elevated IOP. Although this does not imply that all patients with borderline or elevated IOP should receive medication, clinicians should consider initiating treatment for individuals with ocular hypertension who are at moderate or high risk for developing POAG.

Administration, Topical↗
PubMed2002

The Ocular Hypertension Treatment Study: baseline factors that predict the onset of primary open-angle glaucoma.

BACKGROUND: The Ocular Hypertension Treatment Study (OHTS) has shown that topical ocular hypotensive medication is effective in delaying or preventing the onset of primary open-angle glaucoma (POAG) in individuals with elevated intraocular pressure (ocular hypertension) and no evidence of glaucomatous damage. OBJECTIVE: To describe baseline demographic and clinical factors that predict which participants in the OHTS developed POAG. METHODS: Baseline demographic and clinical data were collected prior to randomization except for corneal thickness measurements, which were performed during follow-up. Proportional hazards models were used to identify factors that predicted which participants in the OHTS developed POAG. RESULTS: In univariate analyses, baseline factors that predicted the development of POAG included older age, race (African American), sex (male), larger vertical cup-disc ratio, larger horizontal cup-disc ratio, higher intraocular pressure, greater Humphrey visual field pattern standard deviation, heart disease, and thinner central corneal measurement. In multivariate analyses, baseline factors that predicted the development of POAG included older age, larger vertical or horizontal cup-disc ratio, higher intraocular pressure, greater pattern standard deviation, and thinner central corneal measurement. CONCLUSIONS: Baseline age, vertical and horizontal cup-disc ratio, pattern standard deviation, and intraocular pressure were good predictors for the onset of POAG in the OHTS. Central corneal thickness was found to be a powerful predictor for the development of POAG.

Administration, Topical↗
PubMed2002

The Ocular Hypertension Treatment Study: reproducibility of cup/disk ratio measurements over time at an optic disc reading center.

PURPOSE: To determine the reproducibility over time of visual estimates of the horizontal cup/disk ratio by trained technicians from optic disk stereophotographs. METHODS: Baseline optic disk stereophotographs are graded at entry and regraded annually in a masked fashion. The 1,636 participants in the Ocular Hypertension Treatment Study (OHTS) undergo stereoscopic optic disk photography at study entry and annually thereafter. Stereophotographs are graded independently by two technicians at the Optic Disc Reading Center. If the readers' estimates of horizontal cup/disk ratio differ by more than 0.2 disk diameters (DD), they attempt to reach a consensus; if they cannot, the horizontal cup/disk ratio is adjudicated by a glaucoma specialist. RESULTS: The percent of regradings differing by 0.2 DD or more from the estimate of horizontal cup/disk ratio made at entry was 4%, 6%, and 7%, respectively at years 1, 2, and 3. The percent differing by more than 0.2 DD was 1% or less at all years. Intraclass correlation coefficients were 0.93, 0.92, and 0.92, respectively. Estimates of horizontal cup/disk ratio from sequential full-frame photographs and simultaneous split-frame photographs appeared comparable and equally reproducible. Gradings by technicians were comparable to gradings by glaucoma specialists. CONCLUSIONS: High reproducibility between repeated gradings of baseline horizontal cup/disk ratio was achieved by trained technicians adhering to a rigorous protocol. Horizontal cup/disk ratio measurements in OHTS are sufficiently reproducible to provide information about the relationship of cup/disk ratio to the prognosis of individuals with ocular hypertension.

Certification↗