Biomedical subjects

Mae O Gordon

Publications and source records attributed to Mae O Gordon.

27 records · Page 2Linked to original sources

PubMed2004

Baseline risk factors for the development of primary open-angle glaucoma in the Ocular Hypertension Treatment Study.

PURPOSE: Higher baseline pattern standard deviation (PSD) and larger vertical cup-to-disk ratio (VC/D) were factors in the predictive model for the development of primary open-angle glaucoma (POAG) in the Ocular Hypertension Treatment Study. Because early changes in PSD and VC/D may be indicative of early POAG damage, we repeated the prediction model excluding PSD and VC/D. DESIGN: Reanalysis of baseline factors for the development of POAG. METHODS: We compared the hazard ratios for baseline factors predictive of POAG in the multivariate Cox proportional hazards model that included PSD and VC/D and in the model that excluded them. RESULTS: Hazard ratios for baseline factors predictive of POAG in Ocular Hypertension Treatment Study were not substantially affected by the inclusion or exclusion of PSD and VC/D in the proportional hazards model. CONCLUSION: Whether PSD or VC/D was included in the Cox proportional hazards model, the same baseline factors were statistically significant and their hazard ratios were essentially similar.

Glaucoma, Open-Angle↗

PubMed2004

Central corneal thickness and measured IOP response to topical ocular hypotensive medication in the Ocular Hypertension Treatment Study.

PURPOSE: To determine whether central corneal thickness (CCT) correlates with measured intraocular pressure (IOP) response to topical ocular hypotensive medication in the Ocular Hypertension Treatment Study (OHTS). DESIGN: Prospective randomized clinical trial. METHODS: Intraocular pressure measurements were performed by Goldmann applanation tonometry. Central corneal thickness was measured by ultrasonic pachymetry. The following indicators of IOP response to topical ocular hypotensive medication were examined: (1) IOP after an initial four- to six-week one-eyed therapeutic trial of a nonselective beta-blocker (N = 549) or a prostaglandin analog (N = 201); (2) the mean IOP response during 12 to 60 months of follow-up among medication participants (N = 689); (3) the percentage of follow-up visits at which both eyes met the treatment goal; (4). the total number of different medications prescribed to reach treatment goal; and (5) the total number of different medications prescribed multiplied by the number of months each medication was prescribed. RESULTS: Central corneal thickness was inversely related to the IOP response after the initial one-eyed therapeutic trial and during 12 to 60 months of follow-up (P < .05). Mean CCT was not correlated with the number of different medications prescribed during follow-up, the total medication-months, or the percentage of visits at which IOP target was met. CONCLUSIONS: Individuals with thicker corneas had smaller measured IOP responses to ocular hypotensive medication than those with normal or thin corneas. We believe that CCT measurements may be useful in patient management and in interpreting clinical trials of ocular hypotensive medication.

Administration, Topical↗

PubMed2004

Variables affecting rigid contact lens comfort in the collaborative longitudinal evaluation of keratoconus (CLEK) study.

PURPOSE: To identify factors associated with rigid contact lens comfort in keratoconus. METHODS: Baseline data from the 16 Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study clinical sites were analyzed for all patients wearing a rigid contact lens in their more severely keratoconic eye (as determined by steep keratometry). Corneal transplant patients, patients who did not wear a rigid contact lens in either eye, patients who did not wear a rigid lens in their worse eye, and patients with missing contact lens comfort data were excluded from the sample. A total of 751 eyes were included. Variables assessed included measures of disease severity, visual acuity through the patients' habitual rigid contact lenses, contact lens wearing time, the apical fitting relationship of the contact lens, the degree of peripheral clearance, and the presence of corneal scarring and staining. Comfort was measured by asking the patients "In general, how comfortable are your contact lenses?" (1 = very comfortable through 5 = very irritating). RESULTS: Measures of disease severity (steep keratometry and the first definite apical clearance lens) were not associated with lens comfort. There was no difference in self-reported contact lens comfort between patients fitted with apical touch vs. apical clearance. Patients with a peripheral clearance rating of "minimal unacceptable" (more common among patients with milder keratoconus) were approximately half as likely to report good contact lens comfort compared with patients with "average" peripheral clearance (unadjusted odds ratio, 0.39; 95% confidence interval, 0.19 to 0.79). There was no association between contact lens comfort and the other peripheral clearance ratings compared with ratings of average. CONCLUSIONS: There does not appear to be an association between decreasing patient-reported rigid lens comfort and increasing disease severity as measured by steep keratometry or first definite apical clearance lens in this sample. The apical fitting relationship (flat vs. steep) does not appear to be associated with patient-reported comfort. Minimal peripheral clearance may contribute to decreased rigid contact lens comfort in keratoconus.

Adult↗

PubMed2004

Importance of vitreous liquefaction in age-related cataract.

PURPOSE: Vitrectomy is associated with the rapid progression of nuclear cataracts. This study was conducted to test the hypothesis that age-related liquefaction of the vitreous gel may also be associated with lens opacification. METHODS: Lenses from eye bank eyes were graded for nuclear, cortical, and posterior subcapsular opacities, and the amount of liquid vitreous was measured. RESULTS: Nuclear sclerosis (NS) grade, percent liquefaction, and age all correlated highly (P < 0.0001). After adjustment was made for age, the correlation between NS and percent liquefaction was 0.37 (P < 0.0001), and the correlation between age and NS after adjustment for liquefaction was 0.57 (P < 0.0001). After the eyes were stratified into age groups, the correlation between NS and percent liquefaction was found to be highest in eyes from donors aged 51 to 70. Cortical and posterior subcapsular opacities increased with age, but scores for these cataract types did not significantly correlate with vitreous liquefaction. CONCLUSIONS: Loss of vitreous gel during aging increases the risk of nuclear cataracts. Preservation or replacement of the vitreous gel may protect patients from nuclear cataract.

Aged↗

PubMed2003

Classification of visual field abnormalities in the ocular hypertension treatment study.

OBJECTIVES: (1) To develop a classification system for visual field (VF) abnormalities, (2) to determine interreader and test-retest agreement, and (3) to determine the frequency of various VF defects in the Ocular Hypertension Treatment Study. METHODS: Follow-up VFs are performed every 6 months and are monitored for abnormality, indicated by a glaucoma hemifield test result or a corrected pattern SD outside the normal limits. As of January 1, 2002, 1636 patients had 2509 abnormal VFs. Three readers independently classified each hemifield using a classification system developed at the VF reading center. A subset (50%) of the abnormal VFs was reread to evaluate test-retest reader agreement. A mean deviation was calculated separately for the hemifields as an index to the severity of VF loss. MAIN OUTCOME MEASURES: A 97% interreader hemifield agreement. RESULTS: The average hemifield classification agreement (between any 2 of 3 readers) for 5018 hemifields was 97% and 88% for the 1266 abnormal VFs that were reread (agreement between the first and second classifications). Glaucomatous patterns of loss (partial arcuate, paracentral, and nasal step defects) composed the majority of VF defects. CONCLUSION: The Ocular Hypertension Treatment Study classification system has high reproducibility and provides a possible nomenclature for characterizing VF defects.

Antihypertensive Agents↗

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↗

PubMed2002

Baseline visual field characteristics in the ocular hypertension treatment study.

PURPOSE: The Ocular Hypertension Treatment Study (OHTS) seeks to evaluate the safety and efficacy of topical ocular hypotensive medication in preventing or delaying the onset of visual field loss and/or optic nerve damage in ocular hypertensive subjects at risk for developing primary open-angle glaucoma. This study evaluates the baseline visual field test characteristics (visual field status, reliability properties, etc.) of patients who underwent eligibility visual field testing for entry to the OHTS. DESIGN: Cross-sectional study of baseline data as part of a longitudinal randomized clinical trial. PARTICIPANTS: Two thousand eight hundred nineteen ocular hypertensive individuals, aged 40 to 80 (mean age, 55). METHODS: Subjects underwent at least two Humphrey Field Analyzer Program 30-2 Full Threshold visual field examinations in both eyes for study eligibility. A third examination was performed if a prior test was abnormal, questionable, or unreliable. For final eligibility, two sets of visual field examinations had to meet OHTS criteria for reliability and had to be classified as "normal." All OHTS visual field tests of potential subjects were submitted for eligibility assessment to the OHTS Visual Field Reading Center. MAIN OUTCOME MEASURES: The percentage of visual fields that were normal and reliable according to OHTS criteria. RESULTS: Of the subset of 2304 subjects who completed the eligibility assessments, 1828 (79%) were OHTS-eligible based on visual field test requirements. A third eligibility test was required for 11% of all eyes because of unreliable, questionable, or abnormal test results. With the 33% fixation loss cutoff in the OHTS, 97% of all eligibility visual field examinations were reliable and 3% were unreliable. The most frequent cause (69.5%) of unreliability was excessive fixation losses. CONCLUSIONS: Permitting one repeat test after an abnormal or unreliable test allowed an extra 560 patients to be "eligible" for the study based on visual field tests. A clinical screening review of otherwise normal and reliable tests was not restrictive. The adoption of a 33% fixation loss cutoff significantly reduced the number of required retests and prevented study rejection of 89 patients.

Adult↗