Impact of binocular visual field loss on driving performance in glaucoma patients

AIM:To evaluate the driving performance in young and middle-aged Chinese glaucoma patients with mild to severe visual field loss compared to those without glaucoma by using a driving simulation test.METHODS:Twenty-nine participants were included in this study:nine patients with glaucoma but pass the binocular Esterman visual field test,ten patients with glaucoma and fail the binocular Esterman visual field test,and ten age-matched healthy controls.A driving simulation test was designed as a frequency-based analysis of a lanekeeping task.The total performance error,the controlresponse amplitude and delay were calculated.RESULTS:Esterman visual field test fail group showed the longest delay of control-response among three groups(P=0.02).And the delay in lane-keeping task was significantly associated with inferior field of better-eye(r=0.51,P=0.004)and integrated visual field(r=0.55,P=0.002).CONCLUSION:Young and middle-aged glaucoma patients with binocular visual field loss suffered from a longer delay of response in driving simulation test,while inferior visual field having more impact than superior visual field.     

Color doppler imaging in glaucoma patients with asymmetric visual field loss

With color Doppler imaging, we attempted to determine whether glaucoma patients with asymmetric visual field losses had evidence of asymmetric blood flow velocities in the central retinal artery despite similar intraocular pressure (IOP) curves in both eyes. We found that eyes with more severe visual field damage had an increased local resistance to blood flow in the central retinal artery. Thus vascular factors might have important roles in the pathogenesis of primary open-angle glaucoma.     

Functional visual field of patients with visual field loss

To assess the capability of perceiving forms in patients with visual field loss, a concept of functional visual field was introduced based on determinations of the time required for pattern recognition. Two series of stimulus patterns were made of Japanese syllabic hiragana characters drawn with black dots in the background of open circles of various sizes: the clear stimulus had only open circles in the background and the noisy stimulus had black dots scattered in the background. The stimuli were presented for various durations to 15 normal subjects and 25 patients with narrowed visual field; a correlation of the percentages of correct pattern recognition with the stimulus durations permitted calculations of the 50% recognition time. The recognition time was longer with the noisy than with the clear stimuli. The recognition time with a given stimulus size was longer in patients than in normal subjects. In 3 normal subjects the visual field was artificially narrowed and the recognition time was determined. The recognition time could be expressed by a power function of the ratio of the effective visual field diameter to the diameter of the stimulus pattern. On this basis the functional visual field size of a patient was defined as the size of the artificially narrowed visual field of the normal subject that required the same recognition time as that of the patient. The functional visual field of patients could be correlated with the area of the perimetric field with the V/4 target of Goldmann's projection perimeter. The concept of the functional visual field was found to be useful to express the patients' capability for pattern perception.     

Diffuse visual field loss in open-angle glaucoma

Recent studies have suggested that diffuse field loss and localized visual field loss in glaucomatous patients may have different pathophysiologic mechanisms. Testing that hypothesis requires that some patients present with purely localized field loss and other patients with purely diffuse loss. This article describes four highly selected patients with elevated intraocular pressures, bilateral damage to the optic nerve head, one eye with a classic glaucomatous visual field defect and in the other eye, in the absence of opacities in the media, a diffuse loss of the visual field. Although purely localized loss is very common, the report illustrates purely diffuse loss in the absence of other causes.     

Visual field progression in patients with initially unilateral visual field loss from chronic open-angle glaucoma

PURPOSE: To investigate visual field progression in patients with initially unilateral glaucomatous visual field loss, and to determine risk factors for progression. DESIGN: Retrospective observational case series. PARTICIPANTS: Forty-eight consecutive patients with primary open-angle glaucoma, pseudoexfoliative glaucoma, or pigmentary glaucoma, seen over an 18-month period, who initially had unilateral visual field loss as defined by use of modified Anderson criteria. Patients were followed with standard Humphrey perimetry for a minimum of 2 years. METHODS: Progression was defined by use of modified Anderson criteria, and Advanced Glaucoma Intervention Study (AGIS) and Collaborative Initial Glaucoma Treatment Study scores. MAIN OUTCOME MEASURE: Visual field progression. RESULTS: Three patients (6.2%) had fellow eye progression over a mean follow-up of 76 months and duration of disease of 8.7 years. Fellow eye progression correlated with progression of the first-affected eye (P = 0.044). Ten patients (21%) had progression of the first-affected eye; these eyes had a larger initial cup/disc ratio compared with stable eyes (P = 0.041). Increasing initial AGIS score was associated with progression (P: = 0.003). Kaplan-Meier survival analysis estimated the risk of progression at 5 years to be 25% in first-affected eyes and 7.2% in fellow eyes. CONCLUSIONS: In this population, the risk of fellow eye progression in patients with initially unilateral visual field loss from open-angle glaucoma is low. Progression is higher in eyes with visual field loss at initial testing, and the risk of progression increases as the level of initial visual field loss increases.     

Disc and field damage in patients with unilateral visual field loss from primary open-angle glaucoma

To assess the temporal relationship between field and disc change in early glaucoma, 24 patients with unilateral visual field loss from primary open angle glaucoma were identified for planimetric optic disc measurements. Cross-sectional analysis of disc rim area was performed and compared to 25 age-matched normal controls. The mean (±SD) disc rim area in eyes with normal visual fields (1.10 ± 0.31 mm²) was slightly larger than that of eyes with visual field loss (0.90 ± 0.33 mm²). The mean disc rim area in the control group (1.49 ± 0.19 mm²) was significantly different from both sets of eyes in the asymmetric primary open angle glaucoma patients (p = 0.000). These findings support the hypothesis that loss of the optic disc rim can be detected before perimetric abnormalities develop in patients with glaucoma.     

Nerve fiber layer thickness in glaucoma patients with asymmetric hemifield visual field loss

PURPOSE: To investigate the presence of retinal nerve fiber layer (RNFL) thinning and determine the relationship between RNFL thickness and visual field sensitivity loss in glaucoma patients with asymmetric hemifield visual field loss. PATIENTS AND METHODS: Thirty glaucoma patients with asymmetric hemifield visual field loss and 30 normal control subjects were included in the study. RNFL thickness was measured by optical coherence tomography and visual field sensitivity was measured by automated perimetry. Glaucoma patients with advanced visual field loss restricted to 1 hemifield and early or absent glaucomatous field loss in the other hemifield on the basis of the visual field data were included. Visual field sensitivity and mean deviation (MD) were averaged separately in each of the 2 hemifields. The hemifields in each eye were categorized as early (MD>or=-6 dB) and advanced (MD<-6 dB) glaucomatous hemifields. RESULTS: RNFL thickness measurements in corresponding (eg, superior peripapillary quadrant with inferior hemifield) advanced glaucomatous hemifields (59+/-16 microm) were significantly (P<0.001) lower than in corresponding early glaucomatous hemifields (90+/-25 microm). The mean RNFL thickness in corresponding advanced and early glaucomatous hemifields were significantly lower than in normal control subjects (P<0.0001). On the basis of the normative database supplied by optical coherence tomography software, 100% and 43% of eyes had abnormal RNFL thickness in corresponding advanced and early glaucomatous hemifields, respectively. A linear correlation was found between RNFL thickness and MD in the early (r=0.6; P<0.001) and advanced (r=0.5; P=0.007) glaucomatous hemifields. CONCLUSIONS: RNFL thinning was present in corresponding hemifields of glaucomatous eyes with minimal visual field defect and correlated with visual field sensitivity loss. Measurement of RNFL thickness has potential for detection of early nerve fiber loss owing to glaucoma.     

Reading performance in patients with central visual field disturbance due to glaucoma

PURPOSE: To evaluate the relationship between central visual field disturbance due to glaucoma and reading performance. SUBJECTS AND METHODS: We evaluated the reading performance of 11 patients (14 eyes) with visual acuities of 1.0 and higher who had absolute scotoma within 3 degrees of the central visual field. The ages of the patients ranged from 37 to 77, with a median of 62 years. Maximum reading speed of texts printed horizontally and vertically was measured using MNREAD-J. Subjective reading difficulties were investigated orally. The relationship between the maximum reading speed of both horizontal and vertical texts, the subjective reading difficulties, the number of quadrants, and the position and continuity of absolute scotoma were evaluated. RESULTS: The mean maximum reading speed for vertical and horizontal texts by the 11 patients was 323 and 335 characters/minute(c/m), respectively, and was not significantly slower than that of normal eyes. In 2 of 14 eyes, a significant (p < 0.05) difference between maximum vertical and horizontal reading speeds was observed. In 3 of 14 eyes, absolute scotoma was distributed continuously in more than 2 adjacent quadrants, and these patients also had subjective reading difficulties. CONCLUSION: Reading difficulty is present in patients having absolute scotoma within 3 degrees of the central visual field when the scotoma involves more than 2 adjacent quadrants.     

Progressive color visual field loss in glaucoma.

Twenty one eyes with primary open angle glaucoma were tested with standard (white stimulus-on-white background) and color (blue stimulus-on-yellow background) visual fields over a range of 6-26 mo. There was no significant increase in threshold between the initial and final standard fields overall or by quadrant (P less than 0.188, overall field). A significant increase in mean log thresholds for all areas of the color visual field (P less than 0.019, overall field) was found. Of the 21 patients, nine worsened by greater than 0.2 log units, two improved by greater than 0.2 log units, seven worsened by less than 0.2 log units, and three improved by less than 0.2 log units. When these same patients were matched to 21 normal eyes by age, lens density, and acuity they showed significantly reduced thresholds throughout their color visual fields (P less than 0.023). Whereas normal age-related increases in threshold for the short-wavelength system are only 0.10 log units per decade (n = 88), 10 glaucomatous eyes with increases of 0.14-0.75 log units were found within only 26 mo. The authors conclude that color visual fields may indicate significant change in visual function before it is apparent on standard visual fields.     

Comparison of visual field progression in patients with normal pressure glaucoma between eyes with and without visual field loss that threatens fixation

AIM: To compare the frequency and site of visual field progression and changes in visual acuity in patients with normal pressure glaucoma (NPG) with and without pre-existing visual field loss. METHOD: Patients with normal tension glaucoma were selected who had at least 10 visual fields over 5 or more years of follow up and no other condition that might influence the visual field or visual acuity. Alternate left and right eyes were selected from patients in random order. These eyes were then subdivided according to visual field defect threatening fixation, visual field defect not threatening fixation, and no visual field defect (fellow eyes). Eyes were defined as showing a threat to fixation according to the presence of a visual field defect involving one of more of four paracentral visual field locations. Pointwise linear regression analysis was applied to each visual field series using PROGRESSOR software. Progression of visual field loss was defined as the appearance of a regression slope 1 dB per year or more with a significance of p<0.01, which remained consistent with the addition of two of three successive visual fields to the series. The number of patients showing progression and the number where progression occurred in one of the four paracentral visual field locations was noted. The number of eyes losing two or more lines of Snellen visual acuity over the follow up period was also noted. RESULTS: 174 eyes of 174 patients were selected. 106 eyes had visual field loss threatening fixation, 46 eyes had visual field loss that did not threaten fixation, and 22 were fellow eyes with normal visual fields. The median follow up was 7.2 years. Eight eyes (36.4%) in the "normal visual fields" group, 31 eyes (67.4%) in the "visual field loss away from fixation" group, and 87 eyes (82.1%) in the "threat to fixation" group showed progression in any part of the visual field. Two eyes (9.1%) in the "normal visual fields" group, nine eyes (19.6%) in the "visual field loss away from fixation" group, and 45 eyes (42.5%) in the "threat to fixation" group showed progression at "threat to fixation". The Cox proportional hazards regression model showed an increased risk of progression at any part of the visual field for female sex and a decreased risk for eyes with normal visual fields. For progression at threat to fixation this model showed an increased risk with pre-existing threat to fixation. Eyes from older patients and those that went on to have progressive visual field loss at fixation were more likely to lose two lines of Snellen visual acuity over the follow up period. CONCLUSION: Since 20-30% of previously field damaged eyes and over 60% without prior field loss fail to demonstrate progressive visual field damage over a long follow up it is recommended that normal pressure glaucoma patients be monitored for progression and that potentially harmful therapy be withheld until progression is demonstrated. Although the presence of visual field loss that threatens fixation does not constitute an increased risk of visual field progression it does indicate an increased risk of further loss of visual field close to fixation which is in turn associated with loss of central acuity. In the light of this finding, patients with visual field loss that threatens fixation should be managed more aggressively.     

Central corneal thickness and visual field loss in fellow eyes of patients with open-angle glaucoma

PURPOSE: To determine the relationship of central corneal thickness (CCT) and visual field loss between fellow eyes in primary open-angle glaucoma. DESIGN: Retrospective, observational case series. METHODS: Records review of glaucoma patients seen at local Veterans Administration eye clinic. Those with CCT measurements performed within one month of visual field testing were included. Patients were excluded with vision below 20/40 or disease that would affect visual fields. Intrasubject (between fellow eyes) differences in CCT, mean deviation (MD), and pattern standard deviation (PSD) were calculated by subtracting left eye value from right eye value. RESULTS: Of the 100 subjects (94 males), the Spearman correlation coefficient between intrasubject differences in CCT vs intrasubject differences in MD was 0.36 (P = .0003). The Spearman correlation for differences in CCT vs differences in PSD was -0.31 (P = .0019). CONCLUSIONS: Our study suggests that worse visual field changes tend to occur in the eye with the thinner cornea.     

Patterns of early visual field loss in open-angle glaucoma

We examined two groups of patients with primary open-angle glaucoma with distinctly different patterns of early visual field loss using two visual field indices: mean defect and loss variance. Patients were selected on the basis of visual field criteria only. Eight patients were selected for diffuse depression of the differential light sensitivity without localized scotomas (mean defect greater than 3.0 decibels, loss variance less than 10.0 decibels). Seven patients were selected for localized scotomas without diffuse depression of the differential light sensitivity (mean defect less than or equal to 3.0 decibels, loss variance greater than or equal to 20.0 decibels). Patients with diffuse depression manifested intraocular pressures that were higher (mean peak pressure +/- S.E.M., 27.6 +/- 1.2 mm Hg) than those with localized defects (22.4 +/- 1.4 mm Hg). The optic disk rim area of the localized loss group (mean +/- S.E.M., 1.02 +/- 0.15 mm2) was significantly smaller (P less than .05) than the disk rim area of the diffuse loss group (1.33 +/- 0.07 mm2). This difference was largely because of thinner temporal disk rims in the localized loss group. Different patterns of visual field loss may be caused by different mechanisms of glaucomatous optic nerve damage.     

Eye movements and reading in glaucoma: observations on patients with advanced visual field loss

Purpose

To investigate the relationship between reading speed and eye movements in patients with advanced glaucomatous visual field (VF) defects and age-similar visually healthy people.

Methods

Eighteen patients with advanced bilateral VF defects (mean age: 71, standard deviation [SD]: 7 years) and 39 controls (mean age: 67, SD: 8 years) had reading speed measured using short passages of text on a computer set-up incorporating eye tracking. Scanpaths were plotted and analysed from these experiments to derive measures of ‘perceptual span’ (total number of letters read per number of saccades) and ‘text saturation’ (the distance between the first and last fixation on lines of text). Another eye movement measure, termed ‘saccadic frequency’ (total number of saccades made to read a single word), was derived from a separate lexical decision task, where words were presented in isolation.

Results

Significant linear association was demonstrated between perceptual span and reading speed in patients (R ²?=?0.42) and controls (R ²?=?0.56). Linear association between saccadic frequency during the LDT and reading speed was also found in patients (R ²?=?0.42), but not in controls (R ²?=?0.02). Patients also exhibited greater average text saturation than controls (P?=?0.004).

Conclusion

Some, but not all, patients with advanced VF defects read slower than controls using short text passages. Differences in eye movement behaviour may partly account for this variability in patients. These patients were shown to saturate lines of text more during reading, which may explain previously-reported difficulties with sustained reading.     

单眼视野损伤程度对青光眼患者双眼视野的影响

目的：探讨单眼视野丢失严重程度对原发性闭角型青光眼、原发性开角型青光眼和正常眼压性青光眼患者双眼视野缺损的影响。

方法：根据双眼单眼视野缺损的阶段,将120例青光眼患者和30例健康参与者分为正常、早期、中度或重度四个阶段。通过整合视野和Esterman双眼视野评估确定双眼视野。在组内和组间比较单眼和双眼视野参数。

结果：对于一只眼睛处于正常或早期阶段而另一只眼睛处于严重阶段的患者,双眼综合视野平均偏差分别为-2.8±1.1、-5.5±1.9dB,以及Esterman的平均得分分别为99.1%±1.7%和95.6%±4.7%。当双眼发展为中度或重度损伤(中度/中度,中度/重度或重度/重度)时,双眼综合视野平均偏差低于-6dB,中度/中度和中度/严重损伤组Esterman的平均得分分别为94.2%±6.0%、94.3%±4.9%,但当双眼处于重度损伤阶段时,Esterman的平均得分迅速从大于90%下降到68.4%±26.3%。

结论：如果一只眼睛处于正常或早期阶段,双眼视野可以保持相对完整。当双眼进展到中度或重度阶段时,通过双眼综合视野平均偏差测量的双眼视野缺损是显著的,并且仅当双眼进入严重阶段时才检测到显著的Esterman双眼视野缺损。