Glaucoma
The Association Between Visual Field Defect Severity and Fear of Falling in Primary Open-Angle Glaucoma Kenya Yuki,1,2 Sachiko Tanabe,1,3 Keisuke Kouyama,4 Kazumi Fukagawa,1,2 Miki Uchino,1 Masaru Shimoyama,1 Naoki Ozeki,1 Daisuke Shiba,1 Yoko Ozawa,1 Takayuki Abe,4 and Kazuo Tsubota1 1
Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan Iidabashi Eye Clinic, Tokyo, Japan 3Tanabe Eye Clinic, Yamanashi, Japan 4 The Center for Clinical Research, Keio University School of Medicine, Tokyo, Japan 2
Correspondence: Kenya Yuki, Department of Ophthalmology, Keio University School of Medicine, Shinanomachi 35, Shinjuku-ku, Tokyo, Japan; [email protected]. KY and ST contributed equally to the work presented here and should therefore be regarded as equivalent authors. Submitted: March 22, 2013 Accepted: October 10, 2013 Citation: Yuki K, Tanabe S, Kouyama K, et al. The association between visual field defect severity and fear of falling in primary open-angle glaucoma. Invest Ophthalmol Vis Sci. 2013;54:7739–7745. DOI:10.1167/ iovs.13-12079
PURPOSE. To determine if glaucomatous visual field defect severity is associated with fear of falling. METHODS. This is a cross-sectional study. A total of 387 consecutive subjects with POAG were enrolled in this study along with 293-ocular disease-free control subjects, who were screened at the same institutions. We defined mild POAG as MD of 6 dB or better, moderate POAG as MD of 6 to 12 dB, and severe POAG as MD of 12 dB or worse in the better eye. All participants were requested to answer a questionnaire on fear of falling. Associations between POAG severity and the prevalence of fear of falling were evaluated with the Cochran-Armitage trend test. Multivariable factors including age-adjusted odds ratios (ORs) for the prevalence of fear of falling and 95% confidence intervals (CIs) were evaluated with logistic regression models. RESULTS. The prevalence of fear of falling was 35/293 (11.9%) in the control group, 38/313 (12.1%) in the mild POAG group, 12/48 (25.0%) in the moderate POAG group, and 6/26 (23.1%) in the severe POAG group, and the trend was statistically significant (P ¼ 0.028 Cochran-Armitage trend test). The adjusted ORs for prevalence in the mild, moderate, and severe POAG groups compared with that in the control group were 1.44 (95% CI: 0.83–2.51), 2.33 (95% CI: 1.00–5.44), and 4.06 (95% CI: 1.39–11.90), respectively. CONCLUSIONS. Among patients with POAG, the severity of visual field defects is associated with fear of falling. (http://www.umin.ac.jp/ctr/index.htm number, UMIN000005574.) Keywords: glaucoma, fear of falling, visual field, quality of life
alls are among the most common physical threats for the elderly. Previous studies estimate that about 30% of individuals over the age of 75 experience falls at least once per year; 10% to 20% of these falls lead to injury, and 5% to 6% result in fracture.1,2 Falls result not only in physical injury, but also have psychological consequences (e.g., fear of falling). Fear of falling has been defined as a concern about falling that makes an individual avoid activities that he or she actually remains capable of taking part in.3 Fear of falling is associated with selfimposed restrictions on activities,4,5 depression,6,7 reduced mobility levels,8 increased risk of actual falling,9 and reduced health-related quality of life (QOL).7 Glaucoma is the second leading cause of blindness in the world, affecting approximately 5 million adults globally.10 Glaucomatous optic neuropathy is a disease that involves slow, progressive loss of retinal ganglion cells, resulting in a concomitant pattern of peripheral and central visual field loss. In one study, subjects with glaucoma were found to be over three times more likely to have fallen in the previous year than healthy controls.11 However, the association between fear of falling and the severity of glaucomatous visual field defects is not yet fully understood.12,13 Ramulu et al.12 compared 83 glaucoma subjects with 60 subjects suspected of having
F
Copyright 2013 The Association for Research in Vision and Ophthalmology, Inc. www.iovs.org j ISSN: 1552-5783
Downloaded From: https://iovs.arvojournals.org/ on 12/25/2018
glaucoma and concluded that fear of falling increased with greater visual field loss (b ¼0.52 logits per 5-dB decrement in the better eye visual field). However, Turano et al.13 failed to show any significant association between glaucoma and fear of falling. The aim of this study was to investigate the prevalence of fear of falling among patients with POAG in comparison with comparably aged healthy subjects, and to examine the association between the prevalence of fear and disease severity. Factors that affect fear of falling among POAG patients were also investigated.
METHODS The procedures used in this study conformed to the tenets of the Declaration of Helsinki and to national (Japanese) and institutional (Keio University School of Medicine) regulations. The study was approved by the ethics committee of Keio University School of Medicine (#2010293). All study subjects signed written informed consent prior to enrollment after explanation of the nature and possible consequences of the study. The study was preregistered in the University Hospital 7739
Fear of Falling and Primary Open-Angle Glaucoma Medical Information Network (UMIN) Clinical Trial Registry (UMIN000005574, http://www.umin.ac.jp/ctr/index.htm).
IOVS j November 2013 j Vol. 54 j No. 12 j 7740 LogMAR, to focus on the association between the glaucomatous visual field defect and fear of falling, while avoiding the effect of poor best-corrected visual acuity.
Study Design and Subject Enrollment A total of 943 consecutive Japanese patients aged between 40 and 85 years who visited Keio University Hospital (Tokyo, Japan), Iidabashi Eye Clinic (Tokyo, Japan), or Tanabe Eye Clinic (Yamanashi, Japan) between May 1, 2011 and November 30, 2011 were screened for eligibility as subjects for this multicenter, cross-sectional study. Subjects with POAG were screened at the glaucoma clinics of the three institutions, and the control subjects were screened at the general outpatient clinics of the same institutions.
Evaluation of Glaucoma Subjects The glaucoma subjects were screened for eligibility with a battery of ophthalmic examinations: slit-lamp biomicroscopy, funduscopy, gonioscopy, IOP measurements with Goldmann applanation tonometry, and visual field examination with a Humphrey visual field analyzer using the 30-2 or 24-2 Swedish Interactive Threshold Algorithm standard strategy (Carl Zeiss Meditec, Dublin, CA). The findings were analyzed by ST, NO, Shingo Hosoda, MS, and KY, all of whom subspecialize in glaucoma. Reliability was confirmed at rates of less that 20% fixation losses, less than 33% false-positive results, and less than 33% false-negative results. In this study, we requested that the patients be re-evaluated for visual field defects until the reliability met prespecified criteria. Therefore, no subjects were excluded for failure to meet the visual field test criteria. POAG was diagnosed on the basis of the presence of the following three sets of findings: (1) glaucomatous optic cupping represented by notch formation, generalized enlargement of cupping, senile sclerotic disc or myopic disc, or nerve fiber layer defects, (2) typical glaucomatous visual field defects such as Bjerrum scotoma, nasal step, or paracentral scotoma compatible with optic disc appearance, and (3) open angle observed on gonioscopy.
Evaluation of Control Subjects We recruited the control subjects without POAG at the general outpatient clinics of the same institutions: Keio University Hospital, Tanabe Eye Clinic, and Iidabashi Eye Clinic. They mostly consisted of individuals who visited the clinics for their annual eye examination, or those with an outer adnexal disease. The control subjects were evaluated by an ophthalmic examination that included best-corrected visual acuity measurements, autorefractometry, slit-lamp biomicroscopy, funduscopy, and IOP measurements with a noncontact tonometer or Goldmann applanation tonometer. Control subjects satisfied both of the following vision-related criteria: (1) free of ocular fundus disease that may affect visual function, and (2) bestcorrected visual acuity in both eyes of less than 0.25 logarithm of the minimum angle of resolution (LogMAR) visual acuity.
Exclusion Criteria Subjects with an ophthalmologic disease other than POAG that could potentially compromise visual acuity or contribute to visual field loss, such as secondary glaucoma or AMD, were excluded. Subjects with a LogMAR best-corrected visual acuity of 0.20 or more were excluded. Subjects were also excluded if they were unable to walk unassisted or had any mental disease that prevented them from understanding the questionnaire. Of the 943 subjects screened, 263 were excluded (Supplementary Table S1). We used a cut-off value of 0.20 LogMAR, not 0.301
Downloaded From: https://iovs.arvojournals.org/ on 12/25/2018
Evaluation of Fear of Falling All participants were requested to answer a questionnaire in Japanese that contained the following questions (translated): 1. Can you walk without assistance? (Yes/No) 2. Do you use a cane or any kind of walking aid? (Yes/No) 3. How long do you spend walking on average per day? (The number of minutes was recorded.) 4. Are you afraid of falling? (Not at all; Not much; Afraid; Very afraid) 5. Have you had any falls in the last year? (Yes/No) In addition, demographic information was elicited on age, sex, height, weight, alcohol intake, smoking history, current illnesses, and medical history (including medications taken orally). In our dichotomous analysis, those who answered ‘‘Afraid’’ or ‘‘Very afraid’’ to question (4) were considered to have fear of falling, and those who answered ‘‘Not at all’’ or ‘‘Not much’’ were considered to have no fear. The question ‘‘Are you afraid of falling?’’ was used in previous studies to provide a hierarchy of fear of falling.14,15
Glaucoma Severity Grading For the purposes of this study, we defined mild POAG as a visual field defect corresponding to an MD of 6 dB or better in the better eye, moderate POAG as corresponding to an MD of 6 to 12 dB, and severe POAG as an MD of 12 dB or worse.16 The eye with better visual field was defined as the eye with the higher (i.e., less negative) MD.
Statistical Analysis Descriptive statistics were calculated for the demographic, medical, and visual function variables. Homogeneity of distributions between the POAG and control groups was examined with ANOVA or Fisher’s exact test, depending on the variables. Associations between POAG severity and the prevalence of fear of falling were evaluated with the Cochran-Armitage trend test, for which exact statistics were used. Pair-wise comparisons of the prevalence of fear of falling between the control group and the three POAG groups combined were performed with the v2 test. For sensitivity analyses, adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated with logistic regression models to examine the effects of confounding factors on the unadjusted results. We used forward stepwise selection to determine which candidate variables were possibly associated with fear of falling (P < 0.1), and thus entered into the model. Factors included glaucoma severity, age, sex, body mass index (BMI), alcohol intake, current smoking habit, presence of diabetes mellitus, hypertension, depression, and presence of comorbid illnesses, previous history of falls, and (1) best-corrected visual acuity in the better eye or (2) that in the worse eye. To examine the association between glaucoma severity and fear of falling, Spearman’s correlation coefficient was used to analyze the association between MD in the better eye and the degree of fear of falling. The difference in walking time between subjects with fear of falling and those without was examined with the Mann– Whitney U test. Multiple linear regression analysis with stepwise variable selection was used to explore independent
IOVS j November 2013 j Vol. 54 j No. 12 j 7741
Fear of Falling and Primary Open-Angle Glaucoma TABLE 1. Characteristics of Subjects
Number Age Sex, M/F BMI Alcohol drinker Current smoker
Controls
Mild Glaucoma
Moderate Glaucoma
Severe Glaucoma
P Value
293 67.6 6 11.1 113/180 22.5 6 3.2 118 (40.3%) 33 (11.3%)
313 64.8 6 10.5 133/180 22.4 6 3.1 148 (47.3%) 35 (11.2%)
48 68.2 6 11.8 26/22 22.5 6 3.0 22 (45.8%) 8 (16.7%)
26 67.3 6 11.0 6/20 22.0 6 2.3 19 (73.1%) 6 (23.1%)
0.007*
The Association Between Visual Field Defect Severity and Fear of Falling in Primary Open-Angle Glaucoma Kenya Yuki,1,2 Sachiko Tanabe,1,3 Keisuke Kouyama,4 Kazumi Fukagawa,1,2 Miki Uchino,1 Masaru Shimoyama,1 Naoki Ozeki,1 Daisuke Shiba,1 Yoko Ozawa,1 Takayuki Abe,4 and Kazuo Tsubota1 1
Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan Iidabashi Eye Clinic, Tokyo, Japan 3Tanabe Eye Clinic, Yamanashi, Japan 4 The Center for Clinical Research, Keio University School of Medicine, Tokyo, Japan 2
Correspondence: Kenya Yuki, Department of Ophthalmology, Keio University School of Medicine, Shinanomachi 35, Shinjuku-ku, Tokyo, Japan; [email protected]. KY and ST contributed equally to the work presented here and should therefore be regarded as equivalent authors. Submitted: March 22, 2013 Accepted: October 10, 2013 Citation: Yuki K, Tanabe S, Kouyama K, et al. The association between visual field defect severity and fear of falling in primary open-angle glaucoma. Invest Ophthalmol Vis Sci. 2013;54:7739–7745. DOI:10.1167/ iovs.13-12079
PURPOSE. To determine if glaucomatous visual field defect severity is associated with fear of falling. METHODS. This is a cross-sectional study. A total of 387 consecutive subjects with POAG were enrolled in this study along with 293-ocular disease-free control subjects, who were screened at the same institutions. We defined mild POAG as MD of 6 dB or better, moderate POAG as MD of 6 to 12 dB, and severe POAG as MD of 12 dB or worse in the better eye. All participants were requested to answer a questionnaire on fear of falling. Associations between POAG severity and the prevalence of fear of falling were evaluated with the Cochran-Armitage trend test. Multivariable factors including age-adjusted odds ratios (ORs) for the prevalence of fear of falling and 95% confidence intervals (CIs) were evaluated with logistic regression models. RESULTS. The prevalence of fear of falling was 35/293 (11.9%) in the control group, 38/313 (12.1%) in the mild POAG group, 12/48 (25.0%) in the moderate POAG group, and 6/26 (23.1%) in the severe POAG group, and the trend was statistically significant (P ¼ 0.028 Cochran-Armitage trend test). The adjusted ORs for prevalence in the mild, moderate, and severe POAG groups compared with that in the control group were 1.44 (95% CI: 0.83–2.51), 2.33 (95% CI: 1.00–5.44), and 4.06 (95% CI: 1.39–11.90), respectively. CONCLUSIONS. Among patients with POAG, the severity of visual field defects is associated with fear of falling. (http://www.umin.ac.jp/ctr/index.htm number, UMIN000005574.) Keywords: glaucoma, fear of falling, visual field, quality of life
alls are among the most common physical threats for the elderly. Previous studies estimate that about 30% of individuals over the age of 75 experience falls at least once per year; 10% to 20% of these falls lead to injury, and 5% to 6% result in fracture.1,2 Falls result not only in physical injury, but also have psychological consequences (e.g., fear of falling). Fear of falling has been defined as a concern about falling that makes an individual avoid activities that he or she actually remains capable of taking part in.3 Fear of falling is associated with selfimposed restrictions on activities,4,5 depression,6,7 reduced mobility levels,8 increased risk of actual falling,9 and reduced health-related quality of life (QOL).7 Glaucoma is the second leading cause of blindness in the world, affecting approximately 5 million adults globally.10 Glaucomatous optic neuropathy is a disease that involves slow, progressive loss of retinal ganglion cells, resulting in a concomitant pattern of peripheral and central visual field loss. In one study, subjects with glaucoma were found to be over three times more likely to have fallen in the previous year than healthy controls.11 However, the association between fear of falling and the severity of glaucomatous visual field defects is not yet fully understood.12,13 Ramulu et al.12 compared 83 glaucoma subjects with 60 subjects suspected of having
F
Copyright 2013 The Association for Research in Vision and Ophthalmology, Inc. www.iovs.org j ISSN: 1552-5783
Downloaded From: https://iovs.arvojournals.org/ on 12/25/2018
glaucoma and concluded that fear of falling increased with greater visual field loss (b ¼0.52 logits per 5-dB decrement in the better eye visual field). However, Turano et al.13 failed to show any significant association between glaucoma and fear of falling. The aim of this study was to investigate the prevalence of fear of falling among patients with POAG in comparison with comparably aged healthy subjects, and to examine the association between the prevalence of fear and disease severity. Factors that affect fear of falling among POAG patients were also investigated.
METHODS The procedures used in this study conformed to the tenets of the Declaration of Helsinki and to national (Japanese) and institutional (Keio University School of Medicine) regulations. The study was approved by the ethics committee of Keio University School of Medicine (#2010293). All study subjects signed written informed consent prior to enrollment after explanation of the nature and possible consequences of the study. The study was preregistered in the University Hospital 7739
Fear of Falling and Primary Open-Angle Glaucoma Medical Information Network (UMIN) Clinical Trial Registry (UMIN000005574, http://www.umin.ac.jp/ctr/index.htm).
IOVS j November 2013 j Vol. 54 j No. 12 j 7740 LogMAR, to focus on the association between the glaucomatous visual field defect and fear of falling, while avoiding the effect of poor best-corrected visual acuity.
Study Design and Subject Enrollment A total of 943 consecutive Japanese patients aged between 40 and 85 years who visited Keio University Hospital (Tokyo, Japan), Iidabashi Eye Clinic (Tokyo, Japan), or Tanabe Eye Clinic (Yamanashi, Japan) between May 1, 2011 and November 30, 2011 were screened for eligibility as subjects for this multicenter, cross-sectional study. Subjects with POAG were screened at the glaucoma clinics of the three institutions, and the control subjects were screened at the general outpatient clinics of the same institutions.
Evaluation of Glaucoma Subjects The glaucoma subjects were screened for eligibility with a battery of ophthalmic examinations: slit-lamp biomicroscopy, funduscopy, gonioscopy, IOP measurements with Goldmann applanation tonometry, and visual field examination with a Humphrey visual field analyzer using the 30-2 or 24-2 Swedish Interactive Threshold Algorithm standard strategy (Carl Zeiss Meditec, Dublin, CA). The findings were analyzed by ST, NO, Shingo Hosoda, MS, and KY, all of whom subspecialize in glaucoma. Reliability was confirmed at rates of less that 20% fixation losses, less than 33% false-positive results, and less than 33% false-negative results. In this study, we requested that the patients be re-evaluated for visual field defects until the reliability met prespecified criteria. Therefore, no subjects were excluded for failure to meet the visual field test criteria. POAG was diagnosed on the basis of the presence of the following three sets of findings: (1) glaucomatous optic cupping represented by notch formation, generalized enlargement of cupping, senile sclerotic disc or myopic disc, or nerve fiber layer defects, (2) typical glaucomatous visual field defects such as Bjerrum scotoma, nasal step, or paracentral scotoma compatible with optic disc appearance, and (3) open angle observed on gonioscopy.
Evaluation of Control Subjects We recruited the control subjects without POAG at the general outpatient clinics of the same institutions: Keio University Hospital, Tanabe Eye Clinic, and Iidabashi Eye Clinic. They mostly consisted of individuals who visited the clinics for their annual eye examination, or those with an outer adnexal disease. The control subjects were evaluated by an ophthalmic examination that included best-corrected visual acuity measurements, autorefractometry, slit-lamp biomicroscopy, funduscopy, and IOP measurements with a noncontact tonometer or Goldmann applanation tonometer. Control subjects satisfied both of the following vision-related criteria: (1) free of ocular fundus disease that may affect visual function, and (2) bestcorrected visual acuity in both eyes of less than 0.25 logarithm of the minimum angle of resolution (LogMAR) visual acuity.
Exclusion Criteria Subjects with an ophthalmologic disease other than POAG that could potentially compromise visual acuity or contribute to visual field loss, such as secondary glaucoma or AMD, were excluded. Subjects with a LogMAR best-corrected visual acuity of 0.20 or more were excluded. Subjects were also excluded if they were unable to walk unassisted or had any mental disease that prevented them from understanding the questionnaire. Of the 943 subjects screened, 263 were excluded (Supplementary Table S1). We used a cut-off value of 0.20 LogMAR, not 0.301
Downloaded From: https://iovs.arvojournals.org/ on 12/25/2018
Evaluation of Fear of Falling All participants were requested to answer a questionnaire in Japanese that contained the following questions (translated): 1. Can you walk without assistance? (Yes/No) 2. Do you use a cane or any kind of walking aid? (Yes/No) 3. How long do you spend walking on average per day? (The number of minutes was recorded.) 4. Are you afraid of falling? (Not at all; Not much; Afraid; Very afraid) 5. Have you had any falls in the last year? (Yes/No) In addition, demographic information was elicited on age, sex, height, weight, alcohol intake, smoking history, current illnesses, and medical history (including medications taken orally). In our dichotomous analysis, those who answered ‘‘Afraid’’ or ‘‘Very afraid’’ to question (4) were considered to have fear of falling, and those who answered ‘‘Not at all’’ or ‘‘Not much’’ were considered to have no fear. The question ‘‘Are you afraid of falling?’’ was used in previous studies to provide a hierarchy of fear of falling.14,15
Glaucoma Severity Grading For the purposes of this study, we defined mild POAG as a visual field defect corresponding to an MD of 6 dB or better in the better eye, moderate POAG as corresponding to an MD of 6 to 12 dB, and severe POAG as an MD of 12 dB or worse.16 The eye with better visual field was defined as the eye with the higher (i.e., less negative) MD.
Statistical Analysis Descriptive statistics were calculated for the demographic, medical, and visual function variables. Homogeneity of distributions between the POAG and control groups was examined with ANOVA or Fisher’s exact test, depending on the variables. Associations between POAG severity and the prevalence of fear of falling were evaluated with the Cochran-Armitage trend test, for which exact statistics were used. Pair-wise comparisons of the prevalence of fear of falling between the control group and the three POAG groups combined were performed with the v2 test. For sensitivity analyses, adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated with logistic regression models to examine the effects of confounding factors on the unadjusted results. We used forward stepwise selection to determine which candidate variables were possibly associated with fear of falling (P < 0.1), and thus entered into the model. Factors included glaucoma severity, age, sex, body mass index (BMI), alcohol intake, current smoking habit, presence of diabetes mellitus, hypertension, depression, and presence of comorbid illnesses, previous history of falls, and (1) best-corrected visual acuity in the better eye or (2) that in the worse eye. To examine the association between glaucoma severity and fear of falling, Spearman’s correlation coefficient was used to analyze the association between MD in the better eye and the degree of fear of falling. The difference in walking time between subjects with fear of falling and those without was examined with the Mann– Whitney U test. Multiple linear regression analysis with stepwise variable selection was used to explore independent
IOVS j November 2013 j Vol. 54 j No. 12 j 7741
Fear of Falling and Primary Open-Angle Glaucoma TABLE 1. Characteristics of Subjects
Number Age Sex, M/F BMI Alcohol drinker Current smoker
Controls
Mild Glaucoma
Moderate Glaucoma
Severe Glaucoma
P Value
293 67.6 6 11.1 113/180 22.5 6 3.2 118 (40.3%) 33 (11.3%)
313 64.8 6 10.5 133/180 22.4 6 3.1 148 (47.3%) 35 (11.2%)
48 68.2 6 11.8 26/22 22.5 6 3.0 22 (45.8%) 8 (16.7%)
26 67.3 6 11.0 6/20 22.0 6 2.3 19 (73.1%) 6 (23.1%)
0.007*
