Lower Baseline Intraocular Pressure Research Articles

Positional and Curvature Difference of Lamina Cribrosa According to the Baseline Intraocular Pressure in Primary Open-Angle Glaucoma: A Swept-Source Optical Coherence Tomography (SS-OCT) Study.

PurposeTo investigate the variation of lamina cribrosa (LC) structure based on the baseline intraocular pressure (IOP) in eyes with primary open-angle glaucoma (POAG) and healthy individuals using swept-source optical coherence tomography.MethodsA total of 108 eyes with POAG and 61 healthy eyes were recruited. Based on the baseline IOP, the POAG eyes were divided into higher-baseline IOP (HTG; baseline IOP > 21 mmHg, n = 38 eyes) and lower-baseline IOP (NTG; baseline IOP ≤ 21 mmHg, n = 70 eyes). The anterior laminar insertion depth (ALID), mean LC depth (mLCD), and the LC curvature index (mLCD–ALID) were measured, and compared among the three groups. The regional variation of LC structure was evaluated by vertical-horizontal ALID difference.ResultsThe mLCD and LC curvature index were greatest in HTG eyes (520.3 ± 123.0 and 80.9 ± 30.7 μm), followed by NTG (463.2 ± 110.5 and 64.5 ± 30.7 μm) and healthy eyes (382.9 ± 107.6 and 47.6 ± 25.7 μm, all P < 0.001). However, there were no significant difference in ALID between HTG and NTG eyes. The vertical-horizontal ALID difference was larger in NTG eyes (72.8 ± 56.2 μm) than in HTG (32.7 ± 61.4 μm, P = 0.004) and healthy eyes (25.5 ± 34.8 μm, P < 0.001).ConclusionsLamina cribrosa position and curvature differed in POAG eyes with low and high IOP. This would support the theory that IOP induced biomechanical effects on the optic play a role on glaucoma.

Long-Term Outcomes and Prognostic Factors of Trabeculectomy following Intraocular Bevacizumab Injection for Neovascular Glaucoma.

PurposeTo evaluate long-term outcomes and identify prognostic factors of trabeculectomy following intraocular bevacizumab injection for neovascular glaucoma.MethodsSixty-one eyes of 54 patients with neovascular glaucoma treated by trabeculectomy following intraocular bevacizumab injection were consecutively enrolled. Surgical success criteria were sufficient intraocular pressure (IOP) reduction (IOP ≤21 mmHg, ≥20% IOP reduction, no additional medications or glaucoma surgeries) without devastating complications (loss of light perception, phthisis bulbi, and endophthalmitis) or significant hypotony (IOP ≤5 mmHg continued ≥6 months and until the last follow-up visit or hypotony requiring intervention). Kaplan-Meier survival curves and Cox regression analysis were used to examine success rates and risk factors for surgical outcomes.ResultsThe follow-up period after trabeculectomy was 45.0 ± 22.2 months (mean ± standard deviation). Surgical success rate was 86.9 ± 4.3% (± standard error), 74.0 ± 6.1%, and 51.3 ± 8.6% at 1, 3, and 5 years. Multivariate Cox regression analysis identified two risk factors; lower preoperative IOP (≤30 mmHg) for surgical failure and hypotony [hazard ratio (HR), 2.92, 6.64; 95% confidence interval (CI), 1.22 to 7.03, 1.47 to 30.0; P = 0.018, 0.014, respectively], and vitrectomy after trabeculectomy for surgical failure with or without hypotony criteria (HR, 2.32, 4.06; 95% CI, 1.02 to 5.28, 1.30 to 12.7; P = 0.045, 0.016, respectively).ConclusionsThe long-term outcomes of trabeculectomy following intraocular bevacizumab injection for neovascular glaucoma were favorable. Lower baseline IOP was associated with development of significant hypotony, while additional vitrectomy was related to insufficient IOP reduction.

Long-term effect of phacoemulsification on trabeculectomy function.

To investigate the long-term effect of phacoemulsification on intraocular pressure (IOP) in trabeculectomized eyes and to identify the factors affecting the IOP changes. In consecutive patients with previous trabeculectomy (TE) who underwent uncomplicated clear cornea phacoemulsification we evaluated intraocular pressure, need of antiglaucomatous medical therapy or glaucoma surgery, and length of glaucoma control without therapy. Glaucoma therapy was prescribed in the presence of IOP >18 mm Hg or worsening of the visual field. A group of trabeculectomized eyes that did not receive cataract surgery was retrospectively selected as a control. Multivariate analysis was used to test factors related to final outcome of the treatment. One hundred and eight eyes with previous TE that received phacoemulsification and 108 controls were included in the study. Phacoemulsification was performed 60±21 months after TE. After a mean follow-up of 66±28 months, mean IOP was significantly increased in the cataract surgery group (by 1.7±4.3 mm Hg) and in the control group (by 2.3±4.3 mm Hg)(both P<0.001); in two groups, respectively, 31 eyes (28.7%) and 17 eyes (15.7%) had received glaucoma therapy (chi-square P=0.030). Factors related to success (no need of therapy) were use of mitomycin-C (MMC) in previous TE (P<0.001), longer time from TE to cataract surgery (P=0.007), higher preoperative bleb score (P=0.021), and lower baseline IOP (P=0.042). Cataract surgery reduces the function of filtering bleb in some eyes. Factors related to low rate of failure are the previous use of MMC during TE, longer time from TE to cataract surgery, and good preoperative aspect of the bleb.

Central retinal venous pressure in eyes of normal-tension glaucoma patients with optic disc hemorrhage.

ObjectiveTo compare central retinal venous pressure (CRVP) among eyes with and without optic disc hemorrhage (ODH) in bilateral normal-tension glaucoma (NTG) patients and NTG eyes without an episode of ODH.MethodsIn this prospective study, 22 bilateral NTG patients showing a unilateral ODH and 29 bilateral NTG patients without an episode of ODH were included. Eyes were categorized into group A (n = 22, eyes with ODH), group B (n = 22, fellow eyes without ODH), and group C (n = 29, NTG eyes without an episode of ODH). A contact lens ophthalmodynamometer was used to measure CRVP and central retinal arterial pressure (CRAP).ResultsIntraocular pressure (IOP) measured on the day of contact lens ophthalmodynamometry showed no difference among groups. However, the mean baseline IOP in group A was significantly lower than that in group C (P = .008). The CRVP in group A (29.1 ± 10.8 mmHg) was significantly lower than that in group C (40.1 ± 8.8 mmHg, P = .001), but similar to that in group B (30.5 ± 8.7 mmHg, P = .409). A similar relationship was noted for CRAP. No significant eye-associated variable for ODH was found in group A and B by conditional logistic regression analysis (all P > 0.05). However, multivariate logistic regression analysis in groups A and C revealed that low mean baseline IOP (odds ratio [OR] = 0.69, 95% confidence interval [CI] 0.49-0.98, P = 0.043) and low CRVP (OR = 0.88, 95% CI 0.80-0.95, P = 0.003) were associated with ODH.ConclusionsCRVP was lower in NTG eyes with ODH than in eyes without an episode of ODH, but similar to that of fellow eyes without ODH. These imply less likelihood of association between increased central retinal venous resistance and ODH.

Anti-inflammatory Therapy after Selective Laser Trabeculoplasty: A Randomized, Double-Masked, Placebo-Controlled Clinical Trial

To investigate the effect of anti-inflammatory therapy on selective laser trabeculoplasty (SLT) outcomes. Randomized, double-masked, placebo-controlled trial. Patients with primary open-angle or pseudo-exfoliation glaucoma. Patients undergoing SLT were randomized to receive placebo (artificial tears), prednisolone acetate 1%, or ketorolac tromethamine 0.5% eye drops 4 times per day for 5 days commencing immediately after SLT. Change in intraocular pressure (IOP) from baseline to the 1-month post-SLT visit. Mean change in IOP at the 1-month primary outcome time point, as well as all other time points, was not significantly different among groups (P = 0.99). Likewise, a repeated-measures, mixed-effects model did not find significant differences in IOP outcome at the 1-month time point (P = 0.95). The IOP was reduced in all groups at the 1-month post-SLT time point and all other time points, and no significant differences were found between groups using separate unadjusted cross-sectional analyses of variance (P > 0.15 for analyses at all time points). Treatment failure rates were not different among groups (P = 0.75), and at 1 year after SLT, the percentage of patients maintaining a 20% IOP reduction ranged from 18% to 22% in the 3 study groups. Anti-inflammatory therapy after SLT does not seem to substantially influence the IOP-lowering effect of SLT. In this study of patients with low baseline IOP, SLT showed limited efficacy in achieving a sustained reduction in IOP.

Intraocular Pressure Control after Trabeculectomy, Phacotrabeculectomy and Phacoemulsification in a Hispanic Population.

ABSTRACTPurpose: To compare the efficacy of different surgical strategies for intraocular pressure (IOP) control in Hispanic glaucoma patients with and without visually significant cataracts.Design: Comparative retrospective consecutive case series.Methods: The charts of 153 consecutive patients with primary open angle glaucoma who underwent either trabeculectomy alone (n = 51), phacotrabeculectomy (n = 51), or phacoemulsification alone (n = 51) were reviewed to compare IOP control, the number of glaucoma medications required postoperatively, and the inci dence of surgical complications.Results: Preoperative IOP was 17.5 ± 5.2 mm Hg in the trabe-culectomy group, 15.4 ± 4.5 mm Hg in the phacotrabeculectomy group and 13.9 ± 2.9 mm Hg in the phacoemulsification group (p < 0.001 for all comparisons). Mean IOP reduction from baseline was 4.2 ± 6.9 (24.6%) for the trabeculectomy group, 2.9 ± 5.0 (20.8%) for the phacotrabeculectomy group, and 0.9 ± 3.4 (6.5%) for the phacoemulsification group (p = 0.009). The number of IOP-lowering medications required postoperatively decreased significantly in all three groups (p = 0.001). The rate of early and late postoperative complications was similar between the trabeculectomy and phacotrabeculectomy groups and less for the phacoemulsification group.Conclusion: Trabeculectomy and phacotrabeculectomy are both viable surgical options for managing open angle glau coma. Both resulted in similar rates of success, IOP reduction, decrease in use of IOP-lowering medications and post operative complication rates. Phacoemulsification alone had a lower success rate and greater need for postoperative IOP-lowering medications compared to trabeculectomy alone or phacotrabeculectomy. Phacoemulsification alone may be a reasonable option for patients with visually significant cataract and lower baseline IOP.How to cite this article: Jung JL, Isida-Llerandi CG, Lazcano-Gomez G, SooHoo JR, Kahook MY. Intraocular Pressure Control after Trabeculectomy, Phacotrabeculectomy and Phaco-emulsification in a Hispanic Population. J Curr Glaucoma Pract 2014;8(2):67-74.

Surgical Decisions in Primary Open Angle Glaucoma with Low or Normal Tension.

ABSTRACTGlaucoma, given its insidious nature, is often coined ‘the sneak thief of sight'. Following this trail of thought, primary open angle glaucoma with low or normal tension (POAGLNT) could be coined ‘the king of thieves'. The lack of a compelling red fag of high intraocular pressure (IOP), together with the diurnal fuctuation of the deceptively low baseline IOP, POAGLNT poses a therapeutic challenge in terms of judging when to intervene, and how.In this review article, we will outline the considerations before undergoing surgery: risk stratification, defining goal in terms of target pressure and IOP modulation. We will also review the strengths, weaknesses and pearls of available options.How to cite this article: Shum JW, Leung DY. Surgical Decisions in Primary Open Angle Glaucoma with Low or Normal Tension. J Current Glau Prac 2013;7(3):121-127.

Walking for a Short Distance at a Brisk Pace Reduces Intraocular Pressure by a Clinically Significant Amount

To determine if walking for a short distance in a natural outdoor setting will have a clinically significant effect on intraocular pressure (IOP). Twenty-five healthy participants (25 eyes) aged 20.8±1.3 years had their IOP measured using noncontact tonometry at baseline, after completing a 1046 m outdoor walking course at a brisk pace and after a 20-minute resting period in a seated position. Repeated-measures analysis of variance was used to compare the average IOP at each time point and Pearson correlation was used to assess relationships between the difference in IOP, baseline IOP, and walking pace. IOP decreased from 16.0±2.6 mm Hg at baseline to 14.6±3.2 mm Hg (-1.4±1.1 mm Hg, P<0.001, 95% confidence interval: +0.7--3.3 mm Hg) after the walk. The IOP remained -0.7 mm Hg below the baseline level (P=0.028, paired t test with Bonferroni correction) after the 20-minute resting period. The decrease in IOP was larger in eyes with a lower baseline IOP (partial Pearson r=0.433, P=0.035, controlled for pace). The average walking pace was 4.7±0.5 km/h and was negatively correlated to the decrease in IOP (partial Pearson r=-0.432, P=0.035, controlled for baseline IOP). The postrest recovery of IOP was greater for participants who demonstrated a greater decrease in IOP during the walking period (Pearson r=-0.427, P=0.033). A short brisk walk caused a clinically significant reduction in IOP by an amount that was related to the relative intensity of the exertion, and it did not recover within a 20-minute period. Clinicians are advised to seek information regarding recent physical activity (including walking) and the subsequent resting period, when highly accurate measurements of IOP are required.

Ab Interno Trabeculectomy Versus Trabeculectomy for Open-Angle Glaucoma

To compare the effect of ab interno trabeculectomy with trabeculectomy. Retrospective, cohort study. A total of 115 patients who underwent ab interno trabeculectomy (study group) compared with 102 patients who underwent trabeculectomy with intraoperative mitomycin as an initial surgical procedure (trabeculectomy group). Inclusion criteria were open-angle glaucoma, age ≥ 40 years, and uncontrolled on maximally tolerated medical therapy. Exclusion criterion was concurrent surgery. Clinical variables were collected from patient medical records. Intraocular pressure (IOP) and Cox proportional hazard ratio (HR) and Kaplan-Meier survival analyses with failure defined as IOP >21 mmHg or less than 20% reduction below baseline on 2 consecutive follow-up visits after 1 month; IOP ≤ 5 mmHg on 2 consecutive follow-up visits after 1 month; additional glaucoma surgery; or loss of light perception vision. Secondary outcome measures include number of glaucoma medications and occurrence of complications. Mean follow-up was 27.3 and 25.5 months for the study and trabeculectomy groups, respectively. Intraocular pressure decreased from 28.1 ± 8.6 mmHg at baseline to 15.9 ± 4.5 mmHg (43.5% reduction) at month 24 in the study group, and from 26.3 ± 10.9 mmHg at baseline to 10.2 ± 4.1 mmHg (61.3% reduction) at month 24 in the trabeculectomy group. The success rates at 2 years were 22.4% and 76.1% in the study and trabeculectomy groups, respectively (P<0.001). Younger age (P = 0.037; adjusted HR, 0.98 per year; 95% confidence interval [CI], 0.97-0.99) and lower baseline IOP (P = 0.016; adjusted HR, 0.96 per 1 mmHg; 95% CI, 0.92-0.99) were significant risk factors for failure in the multivariate analysis of the study group. With the exception of hyphema, the occurrence of postoperative complications was more frequent in the trabeculectomy group (P<0.001). More additional glaucoma procedures were performed after ab interno trabeculectomy (43.5%) than after trabeculectomy (10.8%, P<0.001). Ab interno trabeculectomy has a lower success rate than trabeculectomy. Proprietary or commercial disclosure may be found after the references.

Glaucoma and Clinical Characteristics in Vietnamese Americans

Purpose: To assess the proportions of glaucoma types and clinical characteristics in Vietnamese Americans in a single-center, retrospective study.Methods: Medical charts of Vietnamese-American patients who visited a single private practice in Northern California from 1998–2007 were reviewed. The main outcome measures included the distribution and characteristics of glaucoma types, and clinical parameters associated with the presence of various glaucomas.Results: Data from 2247 patients aged 18–98 years were reviewed. Glaucoma was determined for 305 patients (13.6%). Among this group, 54.8% had primary open-angle glaucoma (POAG), 26.9% had primary angle-closure glaucoma (PACG), 13.4% had mixed mechanism glaucoma (MMG), and 4.9% had secondary glaucoma. In the MMG group (41 patients), 27 patients who initially had open angles developed narrow angles and underwent laser peripheral iridotomy (LPI) with a mean follow up of 6.4 years from the time of iridotomy. The other 13 patients had glaucoma progression with open angles after LPI. One POAG patient had neovascular glaucoma due to retinal vein occlusion several years later. Compared to the PACG group, the MMG group had significantly lower baseline intraocular pressure (25.0 vs. 20.2 mmHg, p = 0.007) but with no difference in biometry.Conclusions: POAG is the major type of glaucoma in this clinic-based Vietnamese population. However, Vietnamese appear to have a relatively higher proportion of PACG than Caucasians and those of African descent. It is recommended that gonioscopy be part of the regular eye check-up for adult Vietnamese patients.

Intraocular pressure reduction with a fixed treatment protocol in the Early Manifest Glaucoma Trial

To evaluate: (i) the relationship between intraocular pressure (IOP) reduction attained with a fixed treatment protocol and the untreated IOP level; (ii) the consistency of IOP reduction over time; and (iii) whether there is a threshold pretreatment IOP level below which IOP reduction might be less effective. Results are based on 128 patients with glaucoma with field defects, who were randomized to the treatment arm of the Early Manifest Glaucoma Trial (EMGT). The EMGT fixed treatment protocol consisted of 360° laser trabeculoplasty and topical betaxolol eye drops B.I.D. Treatment was unchanged as long as progression did not occur. Analyses assessed the initial IOP reduction after 3 months and also the mean reduction based on all follow-up values; IOP changes over time were evaluated with linear regression analysis. Factors influencing initial and mean IOP reduction were also explored using linear models. Mean age at baseline was 68 years, and untreated baseline IOP ranged from 13 to 30.5 mmHg. On average, eyes with higher baseline IOP experienced larger pressure reductions than eyes with lower baseline IOP, whether expressed in mmHg or as percentages. Each mmHg of higher baseline IOP was associated with approximately 0.6 mmHg larger IOP reduction. IOP changed little over time, with 66% of patients changing less than 0.5 mmHg/year, and only 13% (17/128) changing >1.0 mmHg/year. The treatment protocol did not achieve any average IOP reduction in eyes with baseline pressures ≤ 15 mmHg. Factors related to more IOP reduction at 3 months were higher baseline IOP and positive refractive error, while higher baseline IOP and male gender (more reduction) and cardiovascular disease history (less reduction) were associated with mean IOP on treatment. With a fixed treatment protocol, the IOP reduction achieved depended very strongly on baseline untreated IOP levels. There seemed to be a lower threshold around 15 mmHg, where therapy did not result in any reduction of IOP. Our results suggest that when effects of IOP-lowering treatment are reported, whether expressed in mmHg or as a percentage of untreated pressure levels, the baseline IOP levels should be specified as well.

Incorporating corneal pachymetry into the management of glaucoma

Intraocular pressure (IOP) results from a dynamic balance between aqueous humor formation and outflow. The simplest technique to measure IOP is indentation tonometry. Another technique is applanation. These methods are related to the elasticity of the eye, which mainly depends on its thickness and hysteresis. For several decades, Goldmann applanation tonometry has been the most accepted method of measuring IOP; the Goldmann tonometer is still used in all important trials. The relationship between IOP values and central corneal thickness (CCT) is well known; Goldmann stated that this relationship only holds for an average corneal thickness of 520 microm measured by optical pachymetry. The Ocular Hypertension Treatment Study (OHTS) showed that CCT is an important risk factor for a change from ocular hypertension to primary open-angle glaucoma. In a multivariate model that included IOP, CCT was the most powerful component of the predictive model. In the Early Manifest Glaucoma Trial (EMGT) with an 11-year follow-up, CCT was a significant predictive factor for glaucoma progression in patients with higher baseline IOP but not in those with lower baseline IOP. Clinical trials such as the OHTS and EMGT cannot prove that CCT is linked to a risk for glaucoma on a biological level. Thus, in eyes with glaucoma, IOP must be treated because it has a significant influence on progression of glaucoma, regardless of the baseline IOP and CCT.

Predictors of Long-term Progression in the Early Manifest Glaucoma Trial

To determine progression factors at the end of the Early Manifest Glaucoma Trial (EMGT) based on all EMGT patients and evaluate separately patients with higher and lower baseline intraocular pressure (IOP; median split). Cohort of clinical trial participants. Patients with early open-angle glaucoma randomized to argon laser trabeculoplasty plus betaxolol (n = 129) or no immediate treatment (n = 126), examined every 3 months for up to 11 years. Cox proportional hazard analyses, expressed by hazard ratios (HRs) and 95% confidence intervals (CIs). Time to progression, defined by perimetric and photographic disc criteria. Overall progression was 67% when follow-up ended (median, 8 years). Treatment approximately halved progression risk (HR, 0.53; 95% CI, 0.39-0.72); results were similar for patients with higher and lower baseline IOP (HRs, 0.41 and 0.55). Baseline progression factors (HRs, 1.51-2.12; P<0.01) were higher IOP, exfoliation, bilateral disease, and older age, as previously reported. New baseline predictors were lower ocular systolic perfusion pressure in all patients (< or =160 mmHg; HR, 1.42; 95% CI, 1.04-1.94), cardiovascular disease history (HR, 2.75; 95% CI, 1.44-5.26) in patients with higher baseline IOP, and lower systolic blood pressure (BP) (< or =125 mmHg; HR, 0.46; 95% CI, 0.21-1.02) in patients with lower baseline IOP. Postbaseline progression factors were IOP levels at follow-up, with 12% to 13% average increase per millimeter of mercury in all patients (HRs, 1.12-1.13 per mmHg higher) and similar results in patients with higher and lower baseline IOP (HRs, 1.15 and 1.13 per mmHg higher). Disc hemorrhages (HR, 1.02; 95% CI, 1.01-1.03 per percent higher frequency) also predicted progression. Thinner central corneal thickness (CCT) (HR, 1.25; 95% CI, 1.01-1.55 per 40 microm lower) was a new significant factor, a result observed in patients with higher baseline IOP (HR, 1.42; 95% CI, 1.05-1.92 per 40 microm lower) but not lower baseline IOP, with significant IOP-CCT interaction. Treatment and follow-up IOP continued to have a marked influence on progression, regardless of baseline IOP. Other significant factors were age, bilaterality, exfoliation, and disc hemorrhages, as previously determined. Lower systolic perfusion pressure, lower systolic BP, and cardiovascular disease history emerged as new predictors, suggesting a vascular role in glaucoma progression. Another new factor was thinner CCT, with results possibly indicating a preferential CCT effect with higher IOP.

Latanoprost Nonresponders with Open-Angle Glaucoma in the Japanese Population

As some patients show little response to latanoprost, one of the most powerful topical glaucoma medications, we investigated the incidence and clinical profiles of latanoprost nonresponders (LNR) in the Japanese population. We examined 62 glaucoma patients (62 eyes) who had received only latanoprost for more than 3 months. Their mean age was 63.8 +/- 1.8 years; the mean observation period was 9.7 +/- 0.4 months. At 1, 3, 6, and 12 months, their intraocular pressure (IOP) was measured, and the IOP reduction rate (RR) and the rate of LNR, defined as RR of 10% or less, were calculated. We statistically analyzed clinical factors involved in the LNR status of our study population. At 1, 3, 6, and 12 months, RR was 20.1 +/- 2.0%, 18.8 +/- 2.3%, 21.1 +/- 2.8%, and 23.0 +/- 2.6%, respectively. At the same time points, the LNR incidence was 23.1%, 28.1%, 23.5%, and 31.8%, respectively, and significantly higher in patients whose baseline IOP was less than 15 mmHg. Patient sex and age and the glaucoma type played no significant role in the LNR status. The incidence of LNR in the Japanese population, including normal-tension glaucoma (NTG) patients, is higher than among European or American patients. Only low baseline IOP was a significant clinical factor among LNR.

Hypertension, diabetes, and longitudinal changes in intraocular pressure

Purpose Diabetes and hypertension are recognized risk factors for raised intraocular pressure (IOP). This report examines the longitudinal relationship of hypertension and diabetes to a 4-year IOP change in a black population with high prevalence of these conditions. Design Population-based cohort study of a simple random sample of residents of Barbados, West Indies, aged ≥40 years. Participants A total of 2996 persons without open-angle glaucoma or receiving IOP-lowering medication at baseline. Methods Participants underwent standardized examinations including applanation tonometry, measurement of blood pressure, and anthropometric indices; a detailed interview; various ocular measurements; and venipuncture for glycosylated hemoglobin (GHb). Diabetes was defined by self-reported physician diagnosis and hypertension by blood pressure ≥140/90 mmHg and/or treatment history. Main outcome measures The 4-year person-based IOP change between baseline and follow-up was defined as the more positive IOP difference in either eye. Results An IOP >21 mmHg at baseline was more likely in black and in mixed (black and white) participants (age-gender adjusted odds ratio [OR], 3.9 and 3.8, respectively) than in whites. Similarly, these groups had more hypertension (age-gender adjusted OR, 2.4 and 2.1, respectively) and diabetes (age-gender adjusted OR, 3.9 and 1.7, respectively) than did whites. Mean IOP in black participants increased by 2.5 (standard deviation, 3.9) mmHg over 4 years. Multiple regression analyses showed that baseline diabetes history and hypertension, as well as older age, elevated GHb, higher blood pressures, and lower baseline IOP were associated with a 4-year increase of IOP. The association between diabetes history/GHb and IOP increase became borderline/nonsignificant when persons who underwent cataract surgery during follow-up were excluded. Conclusions This report provides new data on the relationship of systemic factors to longitudinal increases in IOP in an African-origin population. Results highlight the increased risk of elevated IOP in populations with high prevalences of diabetes and hypertension.

Effect of pilocarpine in ocular hypotension.

In patients with normal intraocular pressure (IOP), local ocular application of pilocarpine causes IOP elevation, reaching a maximum at 10-20 min, and a subsequent prolonged fall of IOP below the baseline. We have studied the effect of pilocarpine in normal subjects with low baseline IOP (less than 10 mm Hg). The initial rise was larger than in normotensive controls (21 vs. 12%) and the subsequent fall was of similar relative magnitude (20%) as that of normotensives. Lower baseline IOP values were associated with greater initial rises and smaller subsequent falls. The mechanisms that may explain the two phases of IOP response to the administration of pilocarpine are discussed.