The Role of Intraocular Pressure and Systemic Hypertension in the Progression of Glaucomatous Damage to the Macula.

PRCIS: Macular structural and functional parameters were better correlated with pressure-dependent glaucomatous damage than conventional parameters. Self-reported systemic hypertension (HTN) was not associated with structural or functional progression in this cohort. PURPOSE: The aim was to examine the relationships between intraocular pressure (IOP), systemic HTN, and glaucoma progression using structural testing with optical coherence tomography (OCT) and functional testing with visual field (VF). PATIENTS AND METHODS: A total of 191 eyes of 119 patients enrolled in a prospective, longitudinal study (Structural and Functional Progression of Glaucomatous Damage to the Macula study) with a diagnosis of glaucoma were analyzed. Patients were tested with 10-2 and 24-2 VF and spectral-domain OCT obtained at 4 to 6 month intervals. IOP from each visit was collected. Self-reported diagnoses of HTN were reported in 72 eyes (37%) in the patients included. Linear mixed effects regression was used to test the relationship between summary statistics from VF and OCT and HTN diagnosis. The goodness-of-fit of relationships was assessed with Bayesian information criterion. RESULTS: Mean follow-up IOP was most associated with the following OCT parameters: global macula ganglion cell layer (GCL), inferior macula GCL, mean macular vulnerability zone GCL, and mean less vulnerable zone macula GCL, and with the following VF parameters: 10-2 PSD and 10-2 MD. There was no significant difference in rates of progression between HTN and non-HTN patients for any OCT or VF parameter. Models with the best goodness-of-fit for the relationship between HTN and progression were the same as those observed for IOP. CONCLUSION: Macular structural and functional parameters are more sensitive to IOP in terms of glaucomatous progression when compared with more conventional parameters. While HTN was not significantly associated with progression using any parameter, macular structural and functional parameters had a better goodness-of-fit to model progression and may be useful as endpoints.

Retinal ganglion cell and inner plexiform layer thickness measurements in regions of severe visual field sensitivity loss in patients with glaucoma.

PURPOSE: To better understand the effects of severe glaucoma on the thickness of the retinal ganglion cell (RGC) and inner plexiform (IP) layers measured with frequency-domain optical coherence tomography. METHODS: In experiment 1, macular cube scans were obtained in 11 patients with glaucoma and the thickness of both the RGC and IP layers were measured at locations corresponding to 3, 5, and 7° eccentricity. For patients, only locations with total deviation losses of -15 dB or worse on perimetry were included. In experiment 2, higher resolution, horizontal midline scans were obtained from 30 controls in order to obtain a precise measure of the thickness of the RGC and IP layers of the healthy retina. RESULTS: In regions of severe field loss (experiment 1), glaucoma decreased the thickness of both layers, leaving a residual layer. The residual thickness of the IP layer was larger than the residual thickness of the RGC layer. In healthy controls (experiment 2), the RGC layer was about 57% of the RGC+IP layer thickness at 3° as compared with only 36% at 10°, in agreement with a recent histological study. CONCLUSION: Glaucomatous optic neuropathy, with severe losses in visual field sensitivity, decreases the thickness of both the RGC and IP layers, but leaves a residual thickness of both. The IP layer contributes slightly more than the RGC to this residual, even just outside the center of the fovea where the RGC layer thickness exceeds the IP layer thickness in controls.

Baseline mean deviation and rates of visual field change in treated glaucoma patients.

PURPOSE: To evaluate the relationships between baseline visual field (VF) mean deviation (MD) and subsequent progression in treated glaucoma. METHODS: Records of patients seen in a glaucoma practice between 1999 and 2009 were reviewed. Patients with glaucomatous optic neuropathy, baseline VF damage, and ≥8 SITA-standard 24-2 VF were included. Patients were divided into tertiles based upon baseline MD. Automated pointwise linear regression determined global and localized rates (decibels (dB) per year) of change. Progression was defined when two or more adjacent test locations in the same hemifield showed a sensitivity decline at a rate of >1.0 dB per year, P<0.01. RESULTS: For mild, moderate, and severe groups, progression was noted in 29.5, 31.2, and 26.0% of eyes (P=0.50) and global rates of VF change of progressing eyes were -1.3±1.2, -1.01±0.7, and -0.9±0.5 dB/year (P=0.09, analysis of variance). Within these groups, intraocular pressure (IOP) in stable vs progressing eyes were 15.5±3.3 vs 17.0±3.1 (P<0.01), 15.4±3.3 vs 15.9±2.5 (P=0.28), and 14.0±2.8 vs 14.8±2.3 mm Hg (P=0.07). More glaucoma filtering surgeries were performed in eyes with worse MD. There was no significant difference between groups regarding their risk of progression in both univariate (P=0.50) and multivariate (P=0.26) analyses adjusting for differences in follow-up IOP. CONCLUSIONS: After correcting for differences in IOP in treated glaucoma patients, we did not find a relationship between the rate of VF change (dB per year) and the severity of the baseline VF MD. This finding may have been due to more aggressive IOP lowering in eyes with more severe disease. Eyes with lower IOP progressed less frequently across the spectrum of VF loss.

Factors associated with topographic changes of the optic nerve head induced by acute intraocular pressure reduction in glaucoma patients.

PURPOSE: To investigate factors associated with changes in optic nerve head (ONH) topography after acute intraocular pressure (IOP) reduction in patients with primary open-angle glaucoma (POAG). METHODS: Untreated POAG patients (IOP >21 mm Hg) were prospectively enrolled. Systemic and ocular information were collected, including central corneal thickness (CCT) and corneal hysteresis (CH). All patients underwent confocal scanning laser ophthalmoscopy and tonometry (Goldmann) before and 1 h after pharmacological IOP reduction. The mean of three measurements was considered for analysis. Changes in each ONH topographic parameter were assessed (one eye was randomly selected), and those that changed significantly were correlated with patient's systemic and ocular characteristics. RESULTS: A total of 42 patients were included (mean age, 66.7 ± 11.8 years). After a mean IOP reduction of 47.3 ± 11.9%, significant changes were observed in cup area and volume, and in rim area and volume (P < 0.01), but not in mean cup depth (P = 0.80). Multiple regression analysis (controlling for baseline IOP and magnitude of IOP reduction) showed that CH (r(2) = 0.17, P < 0.01) and diabetes diagnosis (r(2) ≥ 0.21, P < 0.01) were negatively correlated with the magnitude of changes in ONH parameters, whereas the cup-to-disc ratio was positively correlated (r(2) = 0.30, P < 0.01). Age, race, disc area, and CCT were not significant (P ≥ 0.12). Including all significant factors in a multivariable model, only the presence of diabetes remained significantly associated with all ONH parameters evaluated (P < 0.01). CONCLUSIONS: Different systemic and ocular factors, such as diabetes, CH, and the relative size of the cup, seem to be associated with the magnitude of changes in ONH topography after acute IOP reduction in POAG patients. These associations partially explain the ONH changes observed in these patients and suggest that other factors are possibly implicated in an individual susceptibility to IOP.

Retinal vascular occlusions occur more frequently in the more affected eye in exfoliation syndrome.

PURPOSE: To evaluate the relationship between retinal vascular occlusions (RVOs) and exfoliation syndrome (XFS) in a cohort of patients with the two conditions. METHODS: We reviewed the records of patients with XFS with or without glaucoma and any type of RVO between 1983 and 2007. Patients with prior incisional surgery or a history of uveitis were excluded. Data collected included demographics, systemic comorbidities, type of RVO, and intraocular pressure (IOP) before the RVO. Slit-lamp biomicroscopy regarding the presence of exfoliation material on the lens capsule and pupillary margin before the vascular event was used to evaluate the laterality and degree of XFS. RESULTS: We identified 36 patients (mean age 78.4+/-8.3 years, 19 women). Most patients were of European descent (34/36) and 20 (56%) had no prior glaucoma diagnosis. The most common retinal vascular events were central retinal vein occlusion (18/36) and BRVO (10/36). Mean IOP between eyes with (19.5+/-6.5 mm Hg) and without (17.9+/-4.8 mm Hg) RVO was similar (P=0.12). RVOs occurred more commonly in the eye with more pronounced XFS in 92% (33/36) of the cases. A similar agreement was found when considering patients with and without glaucoma separately (94% (15/16) vs90% (18/20); P=0.83). In addition, no difference in the agreement percentage was observed when comparing patients with unilateral XFS (87% (13/15)) with all study patients (P=0.87). CONCLUSIONS: Retinal vascular occlusion in patients with XFS occurs most often in the affected or more severely affected eye. As vascular occlusions happened in patients with and without glaucoma in similar proportions, the presence of XFS seems to play an important role in these findings.

A comparison between microperimetry and standard achromatic perimetry of the central visual field in eyes with glaucomatous paracentral visual-field defects.

BACKGROUND AND AIMS: The aim was to correlate retinal sensitivity as determined by scanning laser ophthalmoscope microperimetry (SLO-MP) in glaucomatous eyes with paracentral visual field (VF) defects detected by standard automated perimetry (SAP). METHODS: Twenty eyes with glaucomatous optic neuropathy and an SAP VF defect involving the central 16 test points (at least one point with p<1% in the 24-2 VF) were enrolled. Eyes with diseases other than glaucoma were excluded. All patients underwent SLO-MP and SAP of the central 10 degrees . Results from each eye were divided into four quadrants for analysis. Normal and abnormal quadrants by SAP were compared with the corresponding normal and abnormal quadrants by SLO-MP. Regression analysis was used to correlate the mean threshold values (dB) of SLO-MP and SAP in each quadrant. Macular optical coherence tomography (OCT) was performed when there was a disagreement between functional tests. RESULTS: The mean age and VF mean deviation were 60.8 (13.4) years and -7.3 (6.1) dB, respectively. There was a significant correlation between SLO-MP and SAP results in all quadrants (r(2)> or =0.68, p<0.001). All abnormal SAP quadrants had a corresponding abnormal SLO-MP quadrant. However, 21% of the normal SAP quadrants had an abnormal corresponding microperimetry result; a corresponding significant reduction in total macular thickness measured by OCT was present in 75% of these quadrants. CONCLUSIONS: Macular sensitivity evaluated by SLO-MP correlates significantly with SAP paracentral VF defects. SLO-MP detected retinal sensitivity reduction in areas of OCT structural damage with normal SAP and suggests that subtle paracentral functional deficits may be present in many more eyes with established glaucoma than generally assumed.