Comparison of visual field defects in normal-tension glaucoma and high-tension glaucoma

In a prospective comparison of visual defects in 23 patients with normal-tension glaucoma and 23 with high-tension glaucoma, the groups were matched for equal involvement of the optic disk. F profiles on the Octopus 201 Perimeter were used to quantify thresholds at 1-degree intervals from fixation to define eccentricity, depth, and slope of the scotoma. The mean eccentricity of scotomas in the normal-tension group was 4.86 degrees from fixation; in the high-tension group it was 2.96 degrees. These differences were statistically significant (P less than .01). No statistically significant differences were found between the slopes of the scotomas or depths of the scotomas in the two groups.     

Visual field defects in patients with normal-tension glaucoma and patients with high-tension glaucoma.

We compared the automated visual field test results of 24 patients with normal-tension glaucoma and 24 patients with high-tension glaucoma who were closely matched for the amount of visual field loss to determine any differences in the characteristics of visual field defects between the two groups. Patients were matched with a maximum allowable difference in mean deviation of 0.3 dB. Although the normal-tension group had a greater amount of focal visual field loss (pattern standard deviation), the difference was not statistically significant (P = .628). Additionally, there was no statistically significant difference in the amount of diffuse or focal visual field damage in the superior hemifields between the two groups; however, the patients with normal-tension glaucoma had a significantly greater amount of localized visual field loss in the inferior hemifield than the patients with high-tension glaucoma (P = .015). Our data support the hypothesis that a vascular mechanism may have a greater role in the pathogenesis of optic nerve damage and visual field loss in patients with normal-tension glaucoma than in patients with high-tension glaucoma.     

Visual field damage in normal-tension and high-tension glaucoma

We studied the ocular characteristics of 40 pairs of normal-tension and high-tension glaucoma patients who matched closely for the extent of field damage, pupil size, and visual acuity. To determine if there were differences in visual field damage between patients with normal-tension and high-tension glaucoma, we studied characteristics of the areas of the patients' visual fields that were undisturbed. We computed the number of normal locations, the number of clustered normal locations, and the size of the largest cluster of normal locations. The results showed that for an equivalent extent of damage, the individuals in the normal-tension group had greater areas with normal sensitivity, hence more localized damage. A comparison of the patient data to control data showed that paired differences were larger when the normal-tension member of a pair had a larger value in any of the parameters. The results support the hypothesis that glaucoma patients with lower intraocular pressures have more localized damage and those with higher intraocular pressures have more diffuse damage.     

The influence of intraocular pressure on visual field damage in patients with normal-tension and high-tension glaucoma

There have been several reports to suggest that the type of visual field damage in open-angle glaucoma is influenced by intraocular pressure (IOP). This study was undertaken to determine the extent to which patients with normal-tension (NTG) and high-tension glaucoma (HTG) could be differentiated on the basis of some features of their visual fields. The results from 40 pairs of NTG and HTG patients were matched closely for the extent of visual field damage, pupil size, and visual acuity. Using this pooled material, the authors increased the IOP difference between the two groups in either direction, ie, by either progressively lowering the highest recorded IOP allowed for inclusion in the NTG group or by progressively increasing that required for inclusion in the HTG group. They compared the normal areas of the patients' visual fields by using simple visual field indices designed to quantify the undisturbed field. Using receiver operating characteristics (ROC) analysis, they showed that changing the inclusion criterion in the NTG group resulted in no better separation between the groups. However, when the inclusion criterion was changed in the HTG group, the two groups tended to become more separable. In this case, the degree of separation appeared to be related to the difference in the highest recorded IOP between the two groups although the separation was not complete. These findings show that pressure has a greater influence on the type of visual field damage at the higher end of the IOP spectrum encountered in open-angle glaucoma and suggest that there is no common single pathophysiologic mechanism in this disease.     

Frequency doubling technology perimetry in open-angle glaucoma eyes with hemifield visual field damage: comparison of high-tension and normal-tension groups

PURPOSE: To evaluate the performance of frequency doubling technology (FDT) perimetry in open-angle glaucoma eyes with hemifield visual field damage and to compare it between open-angle glaucoma with high pressure [high-tension glaucoma (HTG)] and those with normal pressure [normal-tension glaucoma (NTG)] groups. METHODS: FDT perimetry with the N-30 full threshold protocol and standard automated perimetry (SAP) using the Humphrey Field Analyzer with the 30-2 full threshold protocol were performed in 20 eyes of 20 HTG patients and 36 eyes of 36 NTG patients with visual field damage confirmed with SAP in only one hemifield. RESULTS: There was no significant difference in demographics, the Heidelberg Retina Tomography indices, and the Humphrey Field Analyzer indices between HTG and NTG groups. Regarding the FDT perimetry results, mean deviation in the global field (P=0.009) and mean sensitivity in the SAP-spared (P=0.001) and SAP-impaired (P=0.011) hemifields were lower; the numbers of FDT abnormal test points (probability of abnormality <5%) in the SAP-spared hemifield were significantly greater (P=0.005) in HTG than in NTG groups. Eyes in which FDT results of the SAP-spared hemifield were judged as abnormal was more frequent in HTG groups (P=0.007). CONCLUSIONS: The performance of FDT perimetry to detect early or preperimetric glaucomatous functional changes should be different between HTG and NTG eyes.     

Comparison of visual field defects between normal-tension and primary open-angle glaucoma in the late stage of the disease

Background: There is a lack of studies focusing on differences in visual field damage between normal-tension glaucoma (NTG) and primary open-angle glaucoma (POAG) in the late stage of the disease. This problem was addressed in 34 NTG cases and 63 POAG cases with a mean deviation (STATPAC) -15 dB. Age, refraction, mean deviation, best corrected visual acuity and sex ratio showed no significant between-group differences. Methods: Total deviation (STATPAC), the difference between the measured threshold and the age-corrected normal reference at each test point of the Humphrey 30-2 or 10-2 program (TD₃₀ or TD₁₀) was used for pointwise between-group comparisons: (1) difference in the TD₃₀ or TD₁₀ at the examination point due to the difference of disease type was examined using logistic discriminant analysis; (2) a relatively spared point in a given visual field was defined as a test point of TD₃₀ or TD₁₀>mean deviation/3 and the incidence was compared pointwise between the two groups. Further, (TD₃₀-mean TD₃₀) or (TD₁₀-mean TD₃₀) was used to compare the diffuseness of the visual field damage. Results and conclusion: The two methods of pointwise betweengroup comparison gave similar results. In late-stage disease, the inferior ceco-central field was found to be significantly less depressed in NTG than in POAG. Between-group difference was also suggested in the damage in the superior field and the lower Bjerrum area and in the diffuseness of the visual field damage.     

Risk factors for progression of visual field abnormalities in normal-tension glaucoma

PURPOSE: To uncover risk factors for the highly variable individual rates of progression in cases of untreated normal-tension glaucoma. METHODS: Visual field data were assembled from 160 subjects (160 eyes) enrolled in the collaborative normal-tension glaucoma study during intervals in which the eye under study was not receiving intraocular pressure-lowering treatment during prerandomization and postrandomization intervals. Analyses included multivariate analysis of time-dependent Cox proportional hazard, Kaplan-Meier analysis of "survival" without an increment of visual field worsening, and comparison of slopes of change in mean deviation global index over time. RESULTS: Most migraine occurred in women, but analysis demonstrated that gender and presence of migraine contribute separately to the overall risk. The risk ratio for migraine, adjusted for the other variables was 2.58 (P =.0058), for disk hemorrhage was 2.72 (P =.0036), and for female gender 1.85 (P =.0622). The average fall in the mean deviation index was faster in nonmigrainous women than in nonmigrainous men (P =.05). Suggesting genetic influence, Asians had a slower rate of progression (P =.005), and the few black patients enrolled had a tendency for faster progression. However, self-declared history of family with glaucoma or treated for glaucoma did not affect the rate of progression. Neither age nor the untreated level of intraocular pressure affected the rate of untreated disease progression, despite their known influence on prevalence. CONCLUSIONS: Whereas risk factors for prevalence help select populations within which to screen for glaucoma, the factors that affect the rate of progression help decide the expected prognosis of the individual's untreated disease and thereby the frequency of follow-up and aggressiveness of the therapy to be undertaken.     

Differentiation by imaging of superior segmental optic hypoplasia and normal-tension glaucoma with inferior visual field defects only

Purpose

To differentiate superior segmental optic hypoplasia (SSOH) from normal-tension glaucoma (NTG) with inferior visual field defects only.

Methods

Eighteen eyes with SSOH (SSOH group) and 19 eyes with NTG (NTG group) were examined by optical coherence tomography (OCT), Heidelberg retina tomography (Heidelberg Retinal Tomograph II, HRT II) and standard automated perimetry.

Results

Retinal nerve fiber layer thickness (RNFLT) based on OCT measurements was significantly reduced (thinner) in the superior to superonasal sectors and significantly greater (thicker) in the inferotemporal sector in the SSOH group than in the NTG group. The cup was significantly smaller and the rim significantly larger in the superotemporal and temporal sectors in the SSOH group than in the NTG group based on HRT II measurements. The greatest area under the receiver operating characteristic curve for discrimination of SSOH from NTG by OCT and HRT II was for the RNFLT ratio of 1 + 2 o’clock/10 + 11 o’clock (0.985) and for the ratio of the superonasal to superotemporal sector of rim to disc area ratio and cup to disc area ratio (0.955), respectively. The frequent location of the inferior visual field defects corresponded to the difference in structural changes in both groups.

Conclusions

Comparison of the superonasal to superotemporal sectors by OCT and HRT II were useful in differentiating SSOH from NTG with only inferior visual field defects.     

Pattern of retinal nerve fiber layer damage in Korean eyes with normal-tension glaucoma and hemifield visual field defect

PURPOSE: To evaluate quantitatively the pattern of retinal nerve fiber layer (RNFL) damage in eyes with normal-tension glaucoma (NTG) with hemifield dominant visual field defects using scanning laser polarimetry. METHODS: Prospectively, 40 consecutive eyes from 40 patients with NTG and hemifield defect based on the findings of examination using the Humphrey Field Analyzer underwent RNFL thickness measurements. Twenty normal eyes from 20 subjects matched in age and refractive error formed a control group. RESULTS: Symmetry, calculated as the ratio of superior to inferior RNFL thickness, showed no statistically significant difference between the study group and the control group ( P=0.50). Overall, 27.5% (11/40 eyes) showed an "abnormal" symmetry index that indicated focal RNFL change. The affected ratio, calculated as the ratio of RNFL thickness in the quadrant corresponding to the hemifield of visual field defect to that of the temporal quadrant was significantly lower in the study group than in the control group ( P<0.0001). A similar finding was noted for the unaffected ratio. CONCLUSION: Despite strict selection of the eyes with visual field defect confined to one hemifield, a mixture of both focal and diffuse RNFL damage was noted, with a common occurrence of symmetrical RNFL thinning in both upper and lower quadrants based on scanning laser polarimetry.     

正常眼压性青光眼与高眼压性青光眼视神经图像分析的对比研究

目的 探讨正常眼压性青光眼 (normal-tension glaucoma, NTG)与高眼压性青光眼(high-tension glaucoma, HTG)视盘和视神经纤维层(retinal nerve fiber layer, RNFL)损害的差异。 方法 选择具有青光眼性视神经损害或RNFL缺损、相应的视野缺损的青光眼患者,NTG至少2次24 h眼压曲线和多次眼压测量均≤21 mm Hg(1 mm Hg =0.133 kPa)，HTG的眼压至少2次测量≥25 mm Hg。患者进行详细的眼科检查，同时用扫描激光偏振仪(scanning laser polarimetry, SLP)、光学相干断层扫描（optical coherence tomography, OCT）和海德堡视网膜成像仪(Heidelberg retinal tomography, HRT)定量测定视盘形态和RNFL厚度。比较两组视盘总体和相同象限测量参数。 结果 30例 NTG和 19例 HTG (共49只眼)患者的平均年龄分别为(59.6±8.6)岁(39～71岁)和(59.2±12.3)岁(36～75岁)。两组间视野缺损的平均偏差(mean deviation, MD)差异不显著(P＞0.05)。HRT测量的视盘 C/D面积比，除鼻侧象限外,NTG者视盘总体和上、下、颞侧3个象限均显著大于HTG者(P＜0.05 ),而盘缘面积小于HTG者(P＜0.05)；两组间其他视盘参数差异不显著。3种激光扫描技术所测定的总体和象限RNFL厚度，两组间差异不显著。 结论 NTG趋向大 C/D面积比和窄盘缘面积。RNFL缺损的形态分布须更精细和节段性分析。 (中华眼底病杂志, 2002, 18: 109-112)     

Risk factors for visual field damage progression in normal-tension glaucoma eyes

· Background: This study was carried out to evaluate intraocular or systemic factors associated with the visual field damage progression in eyes with normal-tension glaucoma (NTG). · Patients and methods: Forty-seven NTG eyes with a minimum follow-up of 5 years were enrolled into the retrospective study. A stepwise regression analysis was performed to correlate the visual field damage progression, expressed as the mean deviation (MD) change per year, with several independent clinical factors including age, history of disc hemorrhage, initial MD, mean intraocular pressure (IOP), peak IOP, diurnal fluctuation of IOP, presence of a β zone of peripapillary atrophy, and use of Ca²⁺-channel blockers. · Results: Statistical analysis revealed that non-use of Ca²⁺-channel blockers (P=0.01), peripapillary atrophy (P=0.03) and disc hemorrhage (P=0.04) were associated with visual loss progression. · Conclusions: Risk factors unrelated to IOP were suggested to be associated with progression of visual field loss. Systemic use of Ca²⁺-channel blockers has a favorable effect on visual field prognosis in NTG eyes. Received: 29 July 1997 Revised version received: 17 November 1997 Accepted: 9 December 1997     

Blood-cell velocity in the nailfold capillaries of patients with normal-tension and high-tension glaucoma

We compared the capillary blood-cell velocity in the fingertips of 30 patients with high-tension glaucoma, 30 patients with normal-tension glaucoma, and 30 control subjects by nailfold capillaroscopy. There were no measurable differences in the morphologic findings. The blood-flow velocity, however, was reduced significantly in the patients with normal-tension glaucoma compared with the control subjects (P less than .05). This difference was especially pronounced after cold provocation (P less than .0005). After cooling, 25 of 30 patients with normal-tension glaucoma had a blood standstill of 12 seconds or more, whereas only three of 30 control subjects and four of 30 patients with high-tension glaucoma had a measurable blood standstill.     

Correlation between hemifield visual field damage and corresponding parapapillary atrophy in normal-tension glaucoma

PURPOSE: To evaluate the correlation between the superior or inferior half area of parapapillary atrophy (PPA) and the corresponding hemifield visual field damage (VFD) in normal-tension glaucoma. DESIGN: Cross-sectional study. METHODS: patients: One hundred nine eyes of 109 consecutive patients with normal-tension glaucoma. observation procedures: Topography parameters of the optic nerve head and PPA (zone beta) area were obtained with the Heidelberg Retina Tomograph (HRT), and VFD was evaluated with the 30 to 2 program of Humphrey Field Analyzer. The HRT parameters and PPA area were determined separately in superior and inferior half regions. main outcome measures: Partial correlation coefficients of the superior and inferior areas of PPA with refractive error, axial length, HRT parameters, and corresponding hemifield VFD. RESULTS: In simple correlation analyses, significant correlation was found between the inferior PPA area and the superior hemifield VFD (Spearman rank correlation coefficient; Rs = -0.32; P < .001) but not between the superior PPA area and the inferior hemifield VFD (Rs = 0.05; P = .6). Age, refractive error, axial length, and height variation contour were associated significantly with the total, superior, and inferior areas of PPA, respectively (P < .01). Multiple regression analyses showed that the superior PPA area was associated significantly with only axial length (P < .001), and the inferior PPA area was associated significantly with the axial length and the superior hemifield VFD (P < .001). CONCLUSIONS: In patients with normal-tension glaucoma, only the inferior half area of PPA correlated significantly with glaucomatous VFD. Axial length and myopia were associated with both the superior and inferior half areas of PPA.     

Long-term follow-up of visual field progression after trabeculectomy in progressive normal-tension glaucoma

OBJECTIVE: To evaluate the long-term effects of trabeculectomy on the progression of visual field damage in patients with progressive normal-tension glaucoma (NTG). DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Twenty-three patients with NTG who had significant progression of visual field damage preoperatively and underwent trabeculectomy using antimetabolites. METHODS: Visual field testing using the Humphrey Visual Field Analyzer was periodically performed before and for at least 5 years after surgery (mean, 6 years). The time course of the mean deviation (MD) and mean of total deviations (TD(mean)) in four separate subfields, superior and inferior cecocentral and superior and inferior arcuate fields, were analyzed using a linear mixed effects model. MAIN OUTCOME MEASURES: Intraocular pressure (IOP), preoperative and postoperative regression coefficients of the time course of MD or TD(mean) in the four subfields, corresponding to the rate of progression of visual field damage. RESULTS: IOP significantly decreased from 16.2 +/- 1.8 mmHg preoperatively to approximately 11 mmHg during the postoperative follow-up period (P < 0.001). The preoperative regression coefficient of MD change was significantly negative (-1.05 [95% confidence interval, -1.28 to -0.82] dB/year, P < 0.001). After surgery, it increased significantly to -0.44 (95% confidence interval, -0.64 to -0.24) dB/year (P < 0.001), but the postoperative value was still significantly negative (P < 0.001). In the superior cecocentral, superior and inferior arcuate fields, preoperative regression coefficients of TD(mean) change were significantly negative (P < 0.001) and significantly increased after surgery (P < 0.01). In the inferior cecocentral field, the preoperative regression coefficient was not significantly different from 0 (P = 0.72) and did not change significantly after surgery (P = 0.15). CONCLUSIONS: Trabeculectomy was statistically associated with slowing further progression of visual field damage in patients with progressive NTG. The progression, however, did not completely stop over the 6-year postoperative follow-up period.     

Diurnal variation in microcirculation of ocular fundus and visual field change in normal-tension glaucoma

PURPOSE: Diurnal variations in microcirculation of the ocular fundus in normal-tension glaucoma (NTG) were examined to compare with the normal control eyes. The correlation between progression of visual field impairment and diurnal variations in ocular circulation was also studied. METHODS: The subjects were 12 patients with NTG and 12 normal controls. Blood pressure (BP), intraocular pressure (IOP), ocular perfusion pressure (OPP), and square blur rate (SBR), an index of microcirculation acquired by the laser speckle method, were measured at 9 a.m. (morning), 3 p.m. (afternoon), and 9 p.m. (night). Diurnal variations in SBR were tested using the Friedman test and Wilcoxon signed ranks test. On the other hand, diurnal variations in BP, IOP, and OPP were tested by the analysis of variance. The visual field was evaluated at the same time as determining diurnal variation and again about 9 months later to calculate the change. The correlation between variation ratio in SBR and the change in visual field was examined by simple regression. RESULTS: A significant decrease (P=0.04) was found in SBR at night, as compared with the morning value, in the optic nerve head (ONH) of NTG, although no significant diurnal variations were found in SBR either in the choroid-retina or in normal control eyes. Other parameters showed no significant diurnal variations. The larger diurnal variation was in SBR of the ONH, and the more exacerbated visual field impairment was (r=0.59, P=0.04). CONCLUSION: These findings suggest that diurnal variations in the microcirculation of the ONH may play a role in the progression of NTG.     

Target intraocular pressure for stability of visual field loss progression in normal-tension glaucoma

Purpose  

To determine the target intraocular pressure (IOP) level in normal-tension glaucoma (NTG) for visual field (VF) stability following trabeculectomy.     

Study on the progression of visual field defect and clinical factors in normal-tension glaucoma

PURPOSE: We investigated the relationship between the progression of visual field defect and clinical factors in patients with normal-tension glaucoma (NTG). SUBJECTS AND METHODS: Forty-eight eyes of 48 NTG patients undergoing more than 5-year follow-up were enrolled in this study. Their visual field defects ranged between Aulhorn's classification stage 2 and 4, and mean deviation (MD) more than -10 dB measured by Humphrey Field Analyzer (HFA). End points of this follow-up study were defined as follows: in HFA STATPAC 2 glaucoma change probability analysis, more than 5 points which significantly deteriorated at p < 0.05 were found at 2 consecutive examinations (Criterion 1) or a significant decrease in MD value at p < 0.025 was encountered at one examination or in MD value at p < 0.05 at consecutive examinations (Criterion 2). RESULTS: During the follow-up period, 18 eyes of 48 patients satisfied Criterion 1 and 21 eyes Criterion 2. There were no significant differences in clinical factors between patients with progression and without progression. By multiple logistic regression analysis, minimum flow velocity of central retinal artery (CRA) showed significant relation (odds ratio for a 1 cm/sec rise = 0.2215; 95% confidence interval: 0.0530-0.9253) to progression of visual field defect in Criterion 1, and minimum flow velocity of CRA (odds ratio for a 1 cm/sec rise = 0.2099; 95% confidence interval: 0.0506-0.8712) and cholesterol (odds ratio for a 1 cm/dl rise = 1.0332; 95% confidence interval: 0.4096-2.6064) showed significant relation in Criterion 2. CONCLUSION: These results suggests that vascular risk factors of ocular blood flow may play a role in the progression of visual field defects in NTG patients.     

Pattern ERG and glaucomatous visual field defects

In the past five years numerous reports have suggested that ganglion cell function can be tested by means of a specialized form of electroretinography, the socalled pattern electroretinogram (PERG). Because of the important potentials of a ganglion cell test for clinical use this technique has been applied by several investigators to patients with (presumed) ganglion cell dysfunction, especially glaucoma. On grounds of principle we had reason to question whether the reported positive results should be attributed to ganglion cell dysfunction or to other factors such as optical disturbances. We investigated in this study the PERG as a function of visual field loss in glaucoma patients with careful control of optical factors. We did not find changes in PERG as a function of field loss. So either field loss is not related to the mass behaviour of ganglion cells, or ganglion cells are not the prime basis of the PERG. We believe the latter to be true.