Frequency doubling technology perimetry abnormalities as predictors of glaucomatous visual field loss

Visual Field Tests: A Narrative Review of Different Perimetric Methods

Visual field (VF) testing dates back to fifth century B.C. It plays a pivotal role in the diagnosis, management, and prognosis of retinal and neurological diseases. This review summarizes each of the different VF tests and perimetric methods, including the advantages and disadvantages and adherence to the desired standard diagnostic criteria. The review targets beginners and eye care professionals and includes history and evolution, qualitative and quantitative tests, and subjective and objective perimetric methods. VF testing methods have evolved in terms of technique, precision, user-friendliness, and accuracy. Consequently, some earlier perimetric techniques, often still effective, are not used or have been forgotten. Newer technologies may not always be advantageous because of higher costs, and they may not achieve the desired sensitivity and specificity. VF testing is most often used in glaucoma and neurological diseases, but new objective methods that also measure response latencies are emerging for the management of retinal diseases. Given the varied perimetric methods available, clinicians are advised to select appropriate methods to suit their needs and target disease and to decide on applying simple vs. complex tests or between using subjective and objective methods. Newer, rapid, non-contact, objective methods may provide improved patient satisfaction and allow for the testing of children and the infirm.

The Role of Retinal Ganglion Cell Structure and Function in Glaucoma

Glaucoma, a leading cause of irreversible blindness globally, primarily affects retinal ganglion cells (RGCs). This review dives into the anatomy of RGC subtypes, covering the different underlying theoretical mechanisms that lead to RGC susceptibility in glaucoma, including mechanical, vascular, excitotoxicity, and neurotrophic factor deficiency, as well as oxidative stress and inflammation. Furthermore, we examined numerous imaging methods and functional assessments to gain insight into RGC health. Finally, we investigated the current possible neuroprotective targets for RGCs that could help with future glaucoma research and management.

A Novel Visual Field Screening Program for Glaucoma With a Head-Mounted Perimeter

PRCIS

A novel visual field screening program with a head-mounted perimeter 'imo' could detect glaucoma at all stages in a short time with high accuracy.

PURPOSE

The present study aimed to examine the accuracy and availability of a novel glaucoma visual field screening program using a head-mounted visual perimeter 'imo.'

PARTICIPANTS AND METHODS

Eyes of 76 non-glaucoma participants and 92 glaucoma patients were examined. All patients underwent visual field tests using the Humphrey Visual Field Analyzer (30-2 or 24-2 Swedish Interactive Thresholding Algorithm standard program) and imo (the visual field screening program). We evaluated five visual field screening program indicators: sensitivity, specificity, positive predictive value, negative predictive value, and testing time. We also evaluated the ability of this visual field screening program to differentiate between glaucoma patients and normal controls using the receiver operating characteristic curves and areas under the receiver operating characteristic curves.

RESULTS

The sensitivity, specificity, positive predictive value, and negative predictive value of the visual field screening program were 76%-100%, 91%-100%, 86%-89%, and 79%-100%, respectively. The visual field screening program test time was 46±13 seconds for normal controls and 61±18, 82±21, and 105±16 econds, respectively for mild, moderate, and advanced-stage patients. The areas under the receiver operating characteristic curves were 0.77, 0.97, and 1.0 in the mild, moderate, and advanced stages, respectively.

CONCLUSIONS

Visual field screening using a head-mounted perimeter 'imo' detected glaucoma at all stages in a short time with high accuracy.

Diagnostic Capability of Isolated-Check Visual Evoked Potential for Early to Moderate Primary Open-Angle Glaucoma

This study aimed to evaluate the diagnostic capability of isolated-check visual evoked potential (icVEP) for primary open-angle glaucoma (POAG) via comparison with visual field (VF) tests and pattern visual evoked potential (PVEP). This cross-sectional study enrolled 68 subjects, including 33 POAG patients and 35 controls. All subjects underwent a complete ophthalmic examination, including icVEP, PVEP, and VF tests. The diagnostic performance, the area under the receiver operating characteristic curve (AUC), the integrated discrimination index (IDI), and the net reclassification index (NRI) were calculated. The clinical benefits of the three tests were compared via decision curve analysis (DCA) of the signal-to-noise ratio (SNR) from icVEP, the P100 latency and amplitude of 1° and 0.25° checks from the PVEP, pattern standard deviation (PSD), and mean deviation (MD) from the VF test. The SNR, MD and PSD, PVEP P100 latency of 0.25° checks, and P100 amplitude (both 1° and 0.25° checks) showed significant differences between the POAG and control groups (* p < 0.05), except for the P100 latency of 1° checks. Regarding diagnostic ability, the three tests, AUC, IDI, and NRI, showed no significant difference (p > 0.05). The DCA showed that the clinical benefits of icVEP (SNR) were comparable to those of VF (MD and PSD) and better than those of PVEP (P100 latency and amplitude). In addition, no significant difference was found in the consistency analysis of the qualitative comparison between the icVEP, VF, and PVEP (McNemar p > 0.05). In this study, icVEP showed a diagnostic ability for early to moderate POAG patients comparable to VF and PVEP. IcVEP might be applied as a supplementary psychophysical examination method in addition to VF examinations for special POAG populations who have difficulty cooperating with the VF examination.

Frequency Doubling Technology Visual Field Loss in Fabry Subjects Related to Retinal Ganglion Cell Function as Explored by ERG and OSOME

Purpose

This study aims to evaluate potential causes of FDT visual field loss in a selected group of Fabry subjects.

Patients and Methods

This is a pilot observational study. Subjects were assessed during 2 visits. The following tests were performed: visual acuity, tonometry, optical coherence tomography (OCT) optic nerve scan, frequency doubling time (FDT) and threshold (SAP) VF, ERG, and Online Spectro-reflectometry Oxygenation Measurement in the Eye (OSOME). Results are compared across visits and, when indicated, interpreted against those collected on non-Fabry population matched for age and sex.

Results

The study population was composed of 3 males (34.3 ± 8.9 y.o.) and 5 females (46.4 ± 6.5 y.o). For all subjects, BCVA remained 6/6 OU throughout the study and OCT optic nerve scans were normal. FDT showed a defect in at least 1 quadrant for all participants, in contrast with SAP. FDT PSD value was found different vs SAP. For ERG, the i-wave (52.1 + 2.7 ms) and B-waves (31.6 ± 2.1 ms) peak times were significantly longer compared to a non-Fabry population (p < 0.05). Overall blood oxygenation varied from 61.3% ± 4% to 68.1% ± 4% at the second visit, suggesting a loss of capillary perfusion. Blood volume varied based on location (superior/inferior), eye tested (OD/OS) and time (visit 1/2). The range of values exceeds normal subjects findings (p < 0.05). Blood volume was correlated to FDT PSD value for the superior area of the optic nerve.

Conclusion

The results suggest that Fabry subjects present FDT deficits and abnormal ERG patterns that may be explained by a retinal dysfunction affecting retinal ganglion cells (RGCs), second to vascular alterations.

Comparison of Retinal Nerve Fiber Layer and Ganglion Cell-Inner Plexiform Layer Thickness Values Using Spectral-Domain and Swept-Source OCT

Purpose

To compare peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell-inner plexiform layer (mGCIPL) thickness measurements obtained with spectral domain optical coherence tomography (SD-OCT) and swept-source OCT (SS-OCT) using an OCT-angiography scanning protocol, and their ability to distinguish among patients with glaucoma, glaucoma suspects (GS), and healthy controls (HC).

Methods

Cross-sectional study of 196 eyes (81 glaucoma, 48 GS, and 67 HC) of 119 participants. Participants underwent peripapillary and macular OCT with SD-OCT and SS-OCT. Parameters of interest were average and sector-wise pRNFL and mGCIPL thickness. Inter-device agreement was investigated with Bland-Altman statistics. Conversion formulas were developed with linear regression. Diagnostic performances were evaluated with area under the receiver operating characteristic curves.

Results

Both SD-OCT and SS-OCT detected a significant pRNFL and mGCIPL thinning in glaucoma patients compared to HC and GS for almost all study sectors. A strong linear relationship between the two devices was present for all quadrants/sectors (R2 ≥ 0.81, P < 0.001), except for the nasal (R2 = 0.49, P < 0.001) and temporal (R2 = 0.62, P < 0.001) pRNFL quadrants. SD-OCT and SS-OCT measurements had a proportional bias, which could be removed with conversion formulas. Overall, the two devices showed similar diagnostic abilities.

Conclusions

Thickness values obtained with SD-OCT and SS-OCT are not directly interchangeable but potentially interconvertible. Both devices have a similar ability to discriminate glaucoma patients from GS and healthy subjects.

Translational Relevance

OCT-Angiography scans can be reliably used to obtain structural metrics in glaucoma patients.

Recent developments in perimetry: test stimuli and procedures

Automated perimetry has evolved substantially in recent years, in part due to modern computer technology that enables more complex visual stimuli and test procedures to be realised than those incorporated in traditional white-on-white luminance increment perimetry. This paper reviews briefly a number of advances in automated perimetry. The review includes discussion of new test types: frequency doubling technology perimetry, short wavelength automated perimetry, flicker perimetry, high-pass resolution perimetry and rarebit perimetry. Test algorithms applied to perimetry such as zippy estimation of sequential thresholds (ZEST), Swedish interactive thresholding algorithm (SITA), tendency-oriented perimetry (TOP) and multi-sampling supra-threshold perimetry are also discussed.

Comparison of vertical cup-to-disc ratio estimates using stereoscopic and monoscopic cameras

BACKGROUND

The use of monoscopic cameras for glaucoma screening is increasing due to their portability, lower cost, and non-mydriatic capabilities. However, it is important to compare the accuracy of such devices with stereoscopic cameras that are used clinically and are considered the gold standard in optic disc assessment. The aim of this study is to compare vertical cup-to-disc ratio (VCDR) estimates obtained using images taken with a monoscopic and stereoscopic camera.

METHODS

Participants were selected from the Tema Eye Survey. Eligible subjects had images of at least one eye taken with two cameras. They were classified as meeting the glaucoma threshold if an eye had a VCDR estimate >97.5th percentile, corresponding to >0.725 for this population. Hence, we used 0.725 as the cutoff to group eyes into two categories: positive and negative. We calculated sensitivity, specificity, and predictive values of VCDR assessed by expert readers at a reading center for monoscopic photos using stereoscopic photos as the gold standard.

RESULTS

Three hundred and seventy-nine eyes of 206 participants were included in the study. Most participants were female (60.2%) and the most common age group was 50-59 years (36.4%). Sixteen eyes met the glaucoma threshold (VCDR > 0.725). Of these, the VCDR estimates of 14 eyes (87.5%) disagreed on the glaucoma threshold from the two cameras. The sensitivity to detect glaucoma with the monoscopic camera was 14.3% (95% CI: 4.0, 40.3).

CONCLUSIONS

The low sensitivity of monoscopic photos suggests that stereoscopic photos are more useful in the diagnosis of glaucoma.

Functional assessment of glaucoma: Uncovering progression

Clinicians who manage glaucoma patients carefully monitor the visual field to determine if treatments are effective or interventions are needed. Visual field tests may reflect disease progression or variability among examinations. We describe the approaches and perimetric tests used to evaluate glaucomatous visual field progression and factors that are important for identifying progression. These include stimulus size, which area of the visual field to assess (central versus peripheral), and the testing frequency, evaluating which is important to detect change early while minimizing patient testing burden. We also review the different statistical methods developed to identify change. These include trend- and event-based analyses, parametric and nonparametric tests, population-based versus individualized approaches, as well as pointwise and global analyses. We hope this information will prove useful and important to enhance the management of glaucoma patients. Overall, analysis procedures based on series of at least 5 to 6 examinations that require confirmation and persistence of changes, that are guided by the pattern and shape of the glaucomatous visual field deficits, and that are consistent with structural defects provide the best clinical performance.

Association between esodeviation and primary open-angle glaucoma: the 2010-2011 Korea National Health and Nutrition Examination Survey

BACKGROUND/AIMS

To evaluate the association between strabismus and primary open-angle glaucoma (POAG) in a representative Korean population.

METHODS

A total of 11 114 participants aged 20 years or older in the Korea National Health and Nutrition Examination Survey database for the years 2010 through 2011 were reviewed. A standardised protocol was used to interview every participant and to perform comprehensive ophthalmic examinations. Glaucoma diagnosis was based on fundus photography and frequency-doubling technology perimetry results, according to the International Society of Geographical and Epidemiological Ophthalmology criteria. Ocular alignment was evaluated using the alternate prism and cover test, and clinically significant horizontal strabismus was defined as exodeviation of ≥15 prism dioptres (PD) and esodeviation of ≥10 PD. Univariate and multivariate regression analyses were used to evaluate the potential risk factors for POAG.

RESULTS

In the Korean population, subjects with clinically significant esodeviation had a much higher prevalence of POAG (12.32%) than those without clinically significant esodeviation (3.14%, p=0.016). After adjusting for age and intraocular pressure, clinically significant esodeviation was independently associated with POAG (OR 7.61, p=0.002).

CONCLUSION

Esodeviation was independently associated with POAG in the Korean population. This could be the result of, at least in part, ocular-adduction-induced greater strain on the temporal optic nerve head and peripapillary tissues, which makes eyes with esodeviation more vulnerable to POAG.

Effects of consumption of coffee, tea, or soft drinks on open-angle glaucoma: Korea National Health and Nutrition Examination Survey 2010 to 2011

We sought to investigate the association between consumption of coffee, tea, or soft drinks and risk of open-angle glaucoma (OAG) among Koreans using nationwide population-based data. This cross-sectional survey was performed through the Korea National Health and Nutrition Examination Survey 2010 to 2011. Participants older than 19 years were included in the sample for analysis after excluding those with any missing data. The diagnosis of OAG was based on the International Society of Geographical and Epidemiological Ophthalmology criteria, and participants without glaucomatous optic neuropathy served as controls. The frequency of beverage consumption during the past 12 months was obtained through a questionnaire. Multivariate logistic regression models were used to determine the relationship between consumption of each type of beverage and prevalence of OAG. A total of 6,681 participants was included in the analysis. The prevalence of OAG was 4.4% (n = 323), including 5.4% (n = 169) among men and 3.5% (n = 154) among women. After adjusting for multiple covariates, coffee consumption was significantly associated with OAG, while no significant association was found between consumption of tea or soft drinks and OAG. Participants who drank coffee had a higher risk of having OAG compared with those who did not drink coffee (odds ratio [OR], 2.40; 95% confidence interval [CI], 1.22–4.72; p = 0.011). In sex-stratified analyses, the robust association of coffee consumption with OAG was observed in men (OR, 3.98; 95% CI, 1.71–9.25; p = 0.001) but not in women. Our results suggest that coffee consumption may affect the risk of OAG, particularly in men.

Significant intraocular pressure associated with open-angle glaucoma: Korea National Health and Nutrition Examination Survey 2010-2011

Objectives

To investigate significant intraocular pressure (IOP) levels associated with the risk of open-angle glaucoma (OAG) in the treatment-naïve Korean population.

Methods

Participants ≥20 years of age in Korea National Health and Nutrition Examination Survey 2010–2011 were divided into two groups, those with higher and lower IOP values, compared with the reference IOP value. We compared the risk of OAG in each group using regression analyses. The IOP value that yielded the highest statistical significance was determined as an IOP significantly associated with the OAG risk.

Results

A total of 7,650 participants (7,292 control, 358 OAG) were included. The mean IOP was significantly higher in OAG group (14.4 ± 2.9 mmHg), compared to control group (13.9 ± 2.7 mmHg, P = 0.022). In association with an increased risk of OAG, the significant IOP value was 18 mmHg (Odds ratio [OR] = 1.79, 95% confidence interval [CI] 1.14–2.80, P = 0.011). Additionally, sex-difference was identified and they were 19 mmHg (OR = 2.79, 95% CI 1.27–6.16, P = 0.011) in men and 18 mmHg (OR = 2.65, 95% CI 1.32–5.33, P = 0.006) in women. The IOP values associated with significantly decreased risk of glaucoma were determined to be 14 mmHg in men (OR = 0.68, 95% CI 0.47–0.99, P = 0.042) and 16 mmHg in women (OR = 0.47, 95% CI 0.27–0.81, P = 0.007).

Conclusions

In consideration of the risk to benefit ratio, the reference IOP level for screening or setting the target IOP for treatment could be considered different from traditional 21 mmHg in Korean population.

Relationships between Obesity, Nutrient Supply and Primary Open Angle Glaucoma in Koreans

To investigate the association between nutrient intake and primary open angle glaucoma (POAG) in Koreans, a population-based, cross-sectional survey, the Korean National Health and Nutrition Examination Survey, was analyzed. Glaucoma diagnosis was based on criteria established by the International Society of Geographic and Epidemiologic Ophthalmology. Multivariate regression analysis was used to assess the correlation between dietary intake and the prevalence of POAG in all enrolled subjects. In the low Body mass index(BMI) group (BMI <18.5), females with POAG had significantly lower intakes of energy, protein, fat, carbohydrate, ash, calcium, phosphorus, sodium, potassium, vitamin A, B-carotene, thiamin, riboflavin, and vitamin C than their non-glaucoma counterparts, based on a multivariate logistic regression analysis (all p < 0.05). In females with a medium BMI (18.5 ≤ BMI < 23), POAG showed a significant association with lower food intake, energy, protein, calcium, phosphorus, potassium, thiamin and niacin. (all p < 0.05). Lower protein thiamine intake in medium BMI males was related to POAG. Low dietary intake of several nutrients showed an association with glaucoma in low BMI female subjects. An insufficient intake of certain nutrients may be associated with an increased risk of glaucoma in Koreans. Further large-scale cohort studies are needed to determine how specific nutrients alter the risk of glaucoma.

Insights for mfVEPs from perimetry using large spatial frequency-doubling and near frequency-doubling stimuli in glaucoma

PURPOSE

To compare two forms of perimetry that use large contrast-modulated grating stimuli in terms of: their relative diagnostic power, their independent diagnostic information about glaucoma and their utility for mfVEPs. We evaluated a contrast-threshold mfVEP in normal controls using the same stimuli as one of the tests.

METHODS

We measured psychophysical contrast thresholds in one eye of 16 control subjects and 19 patients aged 67.8 ± 5.65 and 71.9 ± 7.15, respectively, (mean ± SD). Patients ranged in disease severity from suspects to severe glaucoma. We used the 17-region FDT-perimeter C20-threshold program and a custom 9-region test (R9) with similar visual field coverage. The R9 stimuli scaled their spatial frequencies with eccentricity and were modulated at lower temporal frequencies than C20 and thus did not display a clear spatial frequency-doubling (FD) appearance. Based on the overlapping areas of the stimuli, we transformed the C20 results to 9 measures for direct comparison with R9. We also compared mfVEP-based and psychophysical contrast thresholds in 26 younger (26.6 ± 7.3 y, mean ± SD) and 20 older normal control subjects (66.5 ± 7.3 y) control subjects using the R9 stimuli.

RESULTS

The best intraclass correlations between R9/C20 thresholds were for the central and outer regions: 0.82 ± 0.05 (mean ± SD, p ≤ 0.0001). The areas under receiver operator characteristic plots for C20 and R9 were as high as 0.99 ± 0.012 (mean ± SE). Canonical correlation analysis (CCA) showed significant correlation (r = 0.638, p = 0.029) with 1 dimension of the C20 and R9 data, suggesting that the lower and higher temporal frequency tests probed the same neural mechanism(s). Low signal quality made the contrast-threshold mfVEPs non-viable. The resulting mfVEP thresholds were limited by noise to artificially high contrasts, which unlike the psychophysical versions, were not correlated with age.

CONCLUSION

The lower temporal frequency R9 stimuli had similar diagnostic power to the FDT-C20 stimuli. CCA indicated the both stimuli drove similar neural mechanisms, possibly suggesting no advantage of FD stimuli for mfVEPs. Given that the contrast-threshold mfVEPs were non-viable, we used the present and published results to make recommendations for future mfVEP tests.

Open-angle Glaucoma and Sensorineural Hearing Impairment in the Korean Population

PURPOSE

This study identifies the prevalence and risk factors of sensorineural hearing loss and primary open-angle glaucoma (POAG).

MATERIALS AND METHODS

Patients aged 19 years or older who had undergone both ophthalmologic examination and audiometry as part of the Korea National Health and Nutrition Examination Survey V (2010-2012) were analyzed. Hearing loss was defined as the pure-tone average over 40 decibels based on the automatic hearing test to determine the threshold of airway hearing for each frequency. We investigated the prevalence of glaucoma and hearing loss when they occurred alone or simultaneously. The risk factors for concurrent glaucoma and hearing loss were examined.

RESULT

Among the participants, 6.6% had hearing loss alone, 2.3% had glaucoma alone, and 0.5% had both glaucoma and hearing loss. The weighted prevalence of glaucoma in patients with hearing loss was 7.5%; however, the weighted prevalence of glaucoma was 3.2% among patients without hearing loss, with a significant difference (P < .001). Multivariable logistic regression analysis revealed that the risk factors associated with concurrent glaucoma and hearing loss were age (3.786 times per 10 years, P < .001) and triglyceride level (1.002 times per 1 mg/dL, P = .028).

CONCLUSION

Sensorineural hearing loss and POAG are relevant. If hearing impairment and visual impairment occur together, the quality of life of the patient is worsened and the social burden is greater. Therefore, care should be taken when treating elderly patients with glaucoma.

Associations Among Pregnancy, Parturition, and Open-angle Glaucoma: Korea National Health and Nutrition Examination Survey 2010 to 2011

PURPOSE

The purpose of this study was to investigate the association between factors associated with parturition and open-angle glaucoma (OAG) in Korean females.

METHODS

A population-based, cross-sectional survey was performed from the Korean National Health and Nutrition Examination Survey from 2010 to 2011 and enrolled postmenopausal female participants (n=1798). We obtained information on demographics, comorbidities, and health-related behaviors and performed comprehensive ophthalmic examinations. Multivariate regression analysis was used to assess the correlation between pregnancy and delivery and the prevalence of OAG in all enrolled subjects.

RESULTS

The prevalence of OAG among study participants was 6.42%. There was a significant difference in the number of deliveries and age at first delivery between the OAG group and the nonglaucoma group. In multiple linear regression models adjusted for age, hypertension, and intraocular pressure only pregnancy 1 was associated with higher risk of OAG compared with pregnancy 2 (P=0.023). Subjects who had 3 or 4 deliveries were at higher risk of OAG compared with subjects with 2 deliveries (P=0.027). An age at first delivery of 16 to 20 years or 21 to 23 years was associated with increased OAG risk compared with the reference group (P<0.05).

CONCLUSIONS

A history of three or more deliveries and an age at first delivery younger than 23 years were associated with increased risk of OAG. These results suggest that changes or events during the period from pregnancy to delivery affect the development of glaucoma.

Steady-State Pattern Electroretinogram and Frequency Doubling Technology in Adult Dyslexic Readers

Purpose

Dyslexia is a reading disorder with neurological deficit of the magnocellular pathway. The aim of our study was to evaluate the functionality of the magnocellular-Y (M-Y) retinal ganglion cells in adult dyslexic subjects using steady-state pattern electroretinogram and frequency doubling perimetry.

Methods

Ten patients with dyslexia (7 females and 3 males), mean age 28.7 ± 5.9 years, and 10 subjects without dyslexia (6 females and 4 males), mean age 27.8 ± 4.1 years, were enrolled in the study and underwent both steady-state pattern-electroretinogram examination and frequency doubling perimetry.

Results

There was a significant difference in the amplitude of the steady-state pattern electroretinogram of the dyslexic group and the healthy controls (0.610±0.110 μV vs 1.250±0.296 μV; p=0.0001). Furthermore, in the dyslexic group we found a significant difference between the right eye and the left eye (0.671±0.11 μV vs 0.559±0.15 μV; p=0.001). With frequency doubling perimetry, the pattern standard deviation index increased in dyslexic eyes compared to healthy controls (4.40±0.81 dB vs 2.99±0.35 dB; p=0.0001) and in the left eye versus the right eye of the dyslexic group (4.43±1.10 dB vs 3.66±0.96 dB; p=0.031). There was a correlation between the reduction in the wave amplitude of the pattern electroretinogram and the simultaneous increase in the pattern standard deviation values (r=0.80; p=0.001). This correlation was also found to be present in the left eye (r=0.93; p<0.001) and the right eye (r=0.81; p=0.005) of dyslexic subjects.

Conclusion

Our study shows that there was an alteration of the activity of M-Y retinal ganglion cells, especially in the left eye. It confirms that in dyslexia there is a deficit of visual attention with damage not only of the magnocellular-dorsal pathway but also of the M-Y retinal ganglion cells.

The Association Between Body Mass Index and Open-angle Glaucoma in a South Korean Population-based Sample

PURPOSE

The purpose of this article is to investigate the association between body mass index (BMI) and open-angle glaucoma (OAG) in a sample of the South Korean population.

MATERIALS AND METHODS

The sample consisted of a cross-sectional, population-based sample of 10,978 participants, 40 years of age and older, enrolled in the 2008 to 2011 Korean National Health and Nutrition Examination Survey. All participants had measured intraocular pressure <22 mm Hg and open anterior chamber angles. OAG was defined using disc and visual field criteria established by the International Society for Geographical and Epidemiological Ophthalmology. Multivariable analyses were performed to determine the association between BMI and OAG. These analyses were also performed in a sex-stratified and age-stratified manner.

RESULTS

After adjusting for potential confounding variables, lower BMI (<19 kg/m) was associated with greater risk of OAG compared with normal BMI (19 to 24.9 kg/m) [odds ratio (OR), 2.28; 95% confidence interval (CI), 1.22-4.26]. In sex-stratified analyses, low BMI remained adversely related to glaucoma in women (OR, 3.45; 95% CI, 1.42-8.38) but not in men (OR, 1.72; 95% CI, 0.71-4.20). In age-stratified analyses, lower BMI was adversely related to glaucoma among subjects 40- to 49-year old (OR, 5.16; 95% CI, 1.86-14.36) but differences in glaucoma prevalence were not statistically significant between those with low versus normal BMI in other age strata.

CONCLUSIONS

Lower BMI was associated with increased odds of OAG in a sample of the South Korean population. Multivariate analysis revealed the association to be statistically significant in women and those in the youngest age stratum.

Relationships between Hearing Loss and the Prevalences of Cataract, Glaucoma, Diabetic Retinopathy, and Age-Related Macular Degeneration in Korea

This study was conducted using the database of the Korea National Health and Nutrition Examination Survey to determine whether age-related eye diseases such as cataract, glaucoma, diabetic retinopathy (DR), and age-related macular degeneration (AMD), are related to hearing loss. 12,899 participants ≥ 40 years of age were included. The weighted prevalence of diabetic retinopathy was not significantly different between the normal hearing group and hearing-impaired group, but the weighted prevalences of cataract, glaucoma, early AMD, and late AMD were significantly different in the two groups. The odds ratio for cataract in the hearing-impaired group was 1.373 (1.118–1.687). The odds ratios of glaucoma, DR, early AMD, and late AMD were not significantly different in the hearing-impaired group. Age was significantly associated with the presence of concurrent cataract and hearing impairment by 6.574-fold per decade. Significant factors that increased the risk of concurrent glaucoma and hearing impairment were age, male gender, and triglyceride. Age, ex-smoker, systolic BP elevation, BMI decline, and fasting blood sugar significantly predicted the presence of concurrent DR and hearing loss. In early AMD, age and triglyceride, and in late AMD, age and systolic BP elevations increased the risk of concurrent AMD and hearing impairment.

Validation and reproducibility of the Heidelberg Edge Perimeter in the detection of glaucomatous visual field defects

AIM

To validate the ability of the Heidelberg Edge Perimeter (HEP) in detecting glaucomatous visual field (VF) defects compared to the Octopus Visual Field (OVF) Analyzer and to determine the test-retest repeatability of both modalities.

METHODS

This prospective, cross-sectional study was conducted at Wills Eye Hospital, Philadelphia, PA. Glaucoma subjects and unaffected controls underwent VF testing using HEP standard automated perimetry (SAP) III 30-2 Adaptive Staircase Thresholding Algorithm (ASTA) FAST protocol and OVF G-TOP white-on-white strategy. Testing order was randomized. Pearson's correlation coefficient was calculated for both mean deviation (MD) and pattern standard deviation/square root of loss of variance (PSD/sLV). Receiver operating characteristic (ROC) curves were used to determine the diagnostic abilities of both modalities. Glaucoma subjects returned for repeat testing and intraclass correlation coefficients (ICCs) were calculated to assess test-retest repeatability.

RESULTS

Seventy-nine subjects with glaucoma and 36 unaffected controls were enrolled. HEP and OVF were significantly correlated for both MD (r=-0.84; P<0.01) and PSD/sLV (r=0.79; P<0.01). Areas under the ROC curves (AUCs) were also comparable between HEP and OVF for both MD (0.74 and 0.79, respectively; P=0.26) and PSD/sLV (0.74 and 0.82; P=0.08). ICC was high for both HEP (0.96 for MD, 0.95 for PSD/sLV) and OVF (0.82 and 0.88, respectively). Mean test duration (min) was significantly shorter for OVF (2.63) compared to HEP (5.15; P<0.01).

CONCLUSION

HEP and OVF show strong correlation for both MD and PSD/sLV, and have similar validity for detecting glaucoma. The test-retest repeatability is high for both HEP and OVF, however the average testing duration of HEP is significantly longer than that of OVF.

Applications of Isolated-Check Visual Evoked Potential in Early Stage of Open-Angle Glaucoma Patients

Background:

Standard automated perimetry does not sufficiently detect early open-angle glaucoma (OAG) in the clinic. New visual function tests for early glaucoma damage are therefore needed. The present study evaluated whether an isolated-check visual evoked potential (icVEP) could be used to detect visual function abnormalities in early-stage OAG and to explore potential related factors.

Methods:

This was a cross-sectional study. Thirty-seven OAG patients with early-stage visual field loss (mean deviation ≥ −6.00 dB) detected by the Humphrey Field Analyzer (30-2 SITA program) and 26 controls were included in this study. Optical coherence tomography (OCT) was used to detect retinal nerve fiber layer (RNFL) defects. The icVEP preferentially evaluates the magnocellular-ON pathway. VEPs were recorded and signal-to-noise ratios (SNRs) were derived based on multivariate analysis. Eyes that yielded an SNR ≤1 were considered abnormal. Receiver operating characteristic (ROC) curve analysis was used to estimate the accuracy of group classification. Correlations between SNRs and related factors were analyzed.

Results:

Based on an SNR criterion of 1, the icVEP had a sensitivity of 62.2% and a specificity of 92.3% for diagnosing early-stage OAG with 74.6% classification accuracy. The ROC curve analysis, however, suggested that an SNR criterion of 0.93 would produce the highest classification accuracy (77.3%). Both RNFL thinning in the temporal superior quadrant on OCT and number of abnormal test points in the central 11° visual field (pattern deviation, P < 0.5%) significantly correlated with the SNR (P < 0.05).

Conclusions:

The icVEP detected visual function abnormalities in approximately 3/5 of eyes with early-stage OAG with greater than 90% specificity. SNR correlated with both a decrease in RNFL thickness and severity of central visual field loss.

Development of a new algorithm based on FDT Matrix perimetry and SD-OCT to improve early glaucoma detection in primary care

Purpose

The purpose of this study was to develop an objective algorithm to discriminate the earliest stages of glaucoma using frequency doubling technology (FDT) Matrix perimetry and spectral domain-optical coherence tomography (OCT) technology to improve primary care detection.

Materials and methods

Three hundred six eyes (mean age 58.67±15.12) from 161 patients were included and classified in the following three groups: 101 nonglaucoma (GI-NG), 100 glaucoma suspect (GII-SG), and 105 open-angle glaucoma (GIII-OAG). All participants underwent a visual field exploration using the Humphrey Matrix visual field instrument and retinal nerve fiber layer evaluation using the Topcon 3D OCT-2000. Pattern deviation plot was divided into 19 areas and five aggrupation or quadrants and ranked with a value between 0 and 4 according to its likelihood of normality, and differences among three groups were analyzed. Principal component analysis (PCA) was also used to extract the most notable features of FDT and OCT, and a logistic regression analysis was applied to obtain the classification rules.

Results

Only area numbers 7 and 12 and the central zone of FDT Matrix showed statistical differences (P<0.05) between GI-NG and GII-SG. The classification rules were estimated by the four PCA obtained from FDT Matrix and 3D OCT-2000 in a separate and combined use. Area under the receiver operating characteristic curve was 78.88% with FDT-PCA, 82.09% with OCT-PCA, and 94.27% with combined use of FDT and OCT-PCA to discriminate GI-NG and GII-SG.

Conclusion

The predictive rules based on FDT-PCA or OCT-PCA provide a high sensitivity and specificity to detect the earliest stages of glaucoma and even better in combined use. These predictive rules may help the future development of software for FDT Matrix perimetry and 3D OCT-2000, which will greatly improve their diagnostic ability, making them useful in daily practice in a primary care setting.

A Prospective Longitudinal Study to Investigate Corneal Hysteresis as a Risk Factor for Predicting Development of Glaucoma

PURPOSE

To investigate the role of corneal hysteresis (CH) as a risk factor for development of glaucoma.

DESIGN

Prospective observational cohort study.

METHODS

Two hundred and eighty-seven eyes of 199 patients suspected of having glaucoma were followed for an average of 3.9 ± 1.8 years. All eyes had normal visual fields at baseline. Development of glaucoma was defined as occurrence of 3 consecutive abnormal standard automated perimetry tests during follow-up, defined as pattern standard deviation (PSD) < 5%, and/or Glaucoma Hemifield Test outside normal limits. Measurements of CH were acquired at baseline using the Ocular Response Analyzer (ORA). Univariable and multivariable Cox regression models were used to investigate baseline factors associated with development of visual field loss over time.

RESULTS

Fifty-four (19%) eyes developed repeatable visual field defects during follow-up. Measurements of CH at baseline were significantly lower in patients who developed glaucoma vs those who did not (9.5 ± 1.5 mm Hg vs 10.2 ± 2.0 mm Hg; P = .012). Each 1-mm Hg lower CH was associated with an increase of 21% in the risk of developing glaucoma during follow-up (95% confidence interval [CI]: 1.04-1.41; P = .013). In a multivariable model adjusting for age, intraocular pressure, central corneal thickness, PSD, and treatment, CH was still predictive of development of glaucoma (hazard ratio = 1.20; 95% CI: 1.01-1.42; P = .040).

CONCLUSION

Baseline lower CH measurements were significantly associated with increased risk of developing glaucomatous visual field defects over time. The prospective longitudinal design of this study supports a role of CH as a risk factor for developing glaucoma.

SITA-Standard perimetry has better performance than FDT2 matrix perimetry for detecting glaucomatous progression

PURPOSE

The Humphrey Matrix (FDT2) may be more sensitive in detecting glaucomatous visual field loss than SITA standard automated perimetry (SAP) performed on the Humphrey Field Analyzer (HFA). Therefore, FDT may be a good candidate to determine disease progression in patients with glaucoma. Our aim was to test the hypothesis that automated perimetry using the FDT2 would be equal to, or more effective than, HFA SITA-Standard, in identifying glaucomatous progression.

METHODS

One hundred and twenty patients with glaucoma were tested twice at baseline and every 6 months for 4 years with HFA SITA-Standard and FDT2. FDT2 values were standardised to HFA SAP values. We used pointwise linear regression (PLR) over the full data series to identify glaucomatous progression and generated an array of results using three different criteria: (1) three or more clustered test locations progressing, (2) three or more non-clustered test locations progressing and (3) total number of progressing test locations. We compared HFA SAP and FDT2 for the number of locations signalled by the PLR detection algorithm.

RESULTS

Regardless of the criteria, HFA SAP with SITA-Standard testing detected visual field progression at a higher rate than the FDT2 overall (P<0.001).

CONCLUSION

HFA SAP identifies glaucomatous visual field progression at a rate at least as high if not higher than FDT2.

Peripapillary and Macular Vessel Density in Patients with Primary Open-Angle Glaucoma and Unilateral Visual Field Loss

PURPOSE

To characterize OCT angiography (OCT-A) vessel density of patients with primary open-angle glaucoma (POAG) with unilateral visual field (VF) loss.

DESIGN

Cross-sectional study.

PARTICIPANTS

A total of 33 patients with POAG with a VF defect in 1 eye (mean VF mean deviation [MD], -3.9±3.1 decibels [dB]) and normal VF in the other eye (mean VF MD, -0.2±0.9 dB) and 33 healthy eyes.

METHODS

All subjects underwent OCT-A imaging, spectral-domain (SD)-OCT imaging, and VF testing. OCT-A retinal vascular measurements were summarized as whole image vessel density (wiVD), circumpapillary vessel density (cpVD), and parafoveal vessel density (pfVD). Inter-eye differences in vascular measures, as well as SD OCT retinal nerve fiber layer (RNFL), macular ganglion cell complex (mGCC) thickness, and rim area measurements in glaucoma and healthy eyes were compared. Areas under the receiver operating characteristic curves (AUROCs) were used to evaluate diagnostic accuracy for differentiating between unaffected eyes of patients with POAG and healthy eyes.

MAIN OUTCOME MEASURES

Difference in OCT-A vessel density and SD OCT structural parameters between unaffected eyes of patients with POAG with the fellow affected eyes and healthy controls.

RESULTS

Mean wiVD in unaffected eyes of patients with POAG (52.0%) was higher than in their fellow affected eyes (48.8%) but lower than in healthy eyes (55.9%; P < 0.001). Mean circumpapillary RNFL (cpRNFL) thickness, mGCC thickness, and rim area measurement in unaffected eyes of patients with POAG (87.5 μm, 87.7 μm, and 1.0 mm²) were also higher than those measurements in their fellow eyes (76.5 μm, 79.5 μm, and 0.8 mm²; P < 0.001) and lower than in healthy eyes (98.0 μm, 94.5 μm, and 1.4 mm²; P < 0.001). The AUROCs for differentiating unaffected eyes of patients with POAG from healthy eyes were highest for wiVD (0.84), followed by mGCC (0.78), cpRNFL (0.77), and pfVD (0.69).

CONCLUSIONS

OCT-A measures detect changes in retinal microvasculature before VF damage is detectable in patients with POAG, and these changes may reflect damage to tissues relevant to the pathophysiology of glaucoma. Longitudinal studies are needed to determine whether OCT-A measures can improve the detection or prediction of the onset and progression of glaucoma.

Glaucoma progression detection with frequency doubling technology (FDT) compared to standard automated perimetry (SAP) in the Groningen Longitudinal Glaucoma Study

PURPOSE

To determine the usefulness of frequency doubling perimetry (FDT) for progression detection in glaucoma, compared to standard automated perimetry (SAP).

METHODS

Data were used from 150 eyes of 150 glaucoma patients from the Groningen Longitudinal Glaucoma Study. After baseline, SAP was performed approximately yearly; FDT every other year. First and last visit had to contain both tests. Using linear regression, progression velocities were calculated for SAP (Humphrey Field Analyzer) mean deviation (MD) and FDT MD and the number of test locations with a total deviation probability below p < 0.01 (TD). Progression velocity tertiles were determined and eyes were classified as slowly, intermediately, or fast progressing for both techniques. Comparison between SAP and FDT classifications were made using a Mantel Haenszel chi-square test. Longitudinal signal-to-noise ratios (LSNRs) were calculated, per patient and per technique, defined as progression velocity divided by the standard deviation of the residuals.

RESULTS

Mean (SD) follow-up was 6.4 (1.7) years; median (interquartile range [IQR]) baseline SAP MD -6.6 (-14.2 to -3.6) dB. On average 8.2 and 4.5 tests were performed for SAP and FDT, respectively. Median (IQR) MD slope was -0.16 (-0.46 to +0.02) dB/year for SAP and -0.05 (-0.39 to +0.17) dB/year for FDT. Mantel Haenszel chi-squares of SAP MD vs FDT MD and TD were 12.5 (p < 0.001) and 15.8 (p < 0.001), respectively. LSNRs for SAP MD (median -0.17 yr^-1 ) were better than those for FDT MD (-0.04 yr^-1 ; p = 0.010).

CONCLUSIONS

FDT may be a useful technique for monitoring glaucoma progression in patients who cannot perform SAP reliably.

Diagnostic capability of Pulsar perimetry in pre-perimetric and early glaucoma

This study aimed to compare the diagnostic capability of Pulsar perimetry (Pulsar) in pre-perimetric glaucoma (PPG) and early glaucoma (EG) with that of Flicker perimetry (Flicker) and spectral-domain optical conference tomography (SD-OCT). This prospective cross-sectional study included 25 eyes of 25 PPG patients, 35 eyes of 35 EG patients, and 42 eyes of 42 healthy participants. The diagnostic capability using the area under the curve (AUC) of the best parameter and agreement of detectability between structural and functional measurements were compared. For PPG patients, the AUC of Pulsar, Flicker, OCT-disc, and OCT-macular was 0.733, 0.663, 0.842, and 0.780, respectively. The AUC of Flicker was significantly lower than that of OCT-disc (p = 0.016). For EG patients, the AUC of Pulsar, Flicker, OCT-disc, and OCT-macular were 0.851, 0.869, 0.907, and 0.861, respectively. There was no significant difference in AUC among these methods. The agreement between structural and functional measurements expressed by kappa value ranged from -0.16 to 0.07 for PPG and from 0.01 to 0.25 for EG. Although the diagnostic capability of Pulsar in the PPG and EG groups was equal to that of Flicker and SD-OCT, the agreements between structural and functional measurements for both PPG and EG were poor.

Comparison of matrix frequency-doubling technology perimetry and standard automated perimetry in monitoring the development of visual field defects for glaucoma suspect eyes

BACKGROUND

Perimetry is indispensable for the clinical management of glaucoma suspects. Our goal is to compare the performance of standard automated perimetry (SAP) and Matrix frequency-doubling technology (FDT) perimetry in monitoring the development of visual field (VF) defects in glaucoma suspect eyes.

METHODS

Longitudinal data of paired SAP and FDT from 221 eyes of 155 glaucoma suspects enrolled in the Diagnostic Innovations in Glaucoma Study or the African Descent and Glaucoma Evaluation Study were included. All eyes had glaucomatous optic neuropathy or ocular hypertension, but normal SAP and FDT results at baseline. The development of glaucomatous VF defects was defined as the presence of a cluster of ≥ 3 (less conservative) or ≥ 4 (more conservative) locations confirmed on ≥ 2 additional consecutive tests. Risk factors for the development of VF defects were analyzed by COX proportional hazard models. After conversion into common logarithmic units, the rates of change of global VF indices were fitted with linear mixed models.

RESULTS

FDT detected more eyes that developed VF defects than SAP using the less conservative criterion, and no significant difference was observed using the more conservative criterion. For those eyes detected by both SAP and FDT, FDT detected the development of VF defects either earlier than SAP or simultaneously in most cases. Baseline structural measurements were not significantly associated with an increased risk for the development of glaucomatous VF defects on either SAP or FDT. Older age was significantly associated with the development of VF defects on FDT but not on SAP. Both SAP and FDT detected a progressing worsening trend of pattern standard deviation over time with a similar rate of change between these test types.

CONCLUSIONS

Matrix FDT would be useful to monitor the onset of VF defects in glaucoma suspects and may outperform SAP in the early stage of glaucomatous VF damage.

Structural and functional brain changes in early- and mid-stage primary open-angle glaucoma using voxel-based morphometry and functional magnetic resonance imaging

To investigate structural and functional brain changes in patients with primary open-angle glaucoma (POAG) by using voxel-based morphometry based on diffeomorphic anatomical registration through exponentiated Lie algebra (VBM-DARTEL) and blood oxygenation level dependent functional magnetic resonance imaging (BOLD-fMRI), respectively.Thirteen patients diagnosed with POAG and 13 age- and sex-matched healthy controls were enrolled in the study. For each participant, high-resolution structural brain imaging and blood flow imaging were acquired on a 3.0-Tesla magnetic resonance imaging (MRI) scanner. Structural and functional changes between the POAG and control groups were analyzed. An analysis was carried out to identify correlations between structural and functional changes acquired in the previous analysis and the retinal nerve fiber layer (RNFL).Patients in the POAG group showed a significant (P < 0.001) volume increase in the midbrain, left brainstem, frontal gyrus, cerebellar vermis, left inferior parietal lobule, caudate nucleus, thalamus, precuneus, and Brodmann areas 7, 18, and 46. Moreover, significant (P < 0.001) BOLD signal changes were observed in the right supramarginal gyrus, frontal gyrus, superior frontal gyrus, left inferior parietal lobule, left cuneus, and left midcingulate area; many of these regions had high correlations with the RNFL.Patients with POAG undergo widespread and complex changes in cortical brain structure and blood flow. (ClinicalTrials.gov number: NCT02570867).

Medical Management of Glaucoma in the 21st Century from a Canadian Perspective

Glaucoma is a medical term describing a group of progressive optic neuropathies characterized by degeneration of retinal ganglion cells and retinal nerve fibre layer and resulting in changes in the optic nerve head. Glaucoma is a leading cause of irreversible vision loss worldwide. With the aging population it is expected that the prevalence of glaucoma will continue to increase. Despite recent advances in imaging and visual field testing techniques that allow establishment of earlier diagnosis and treatment initiation, significant numbers of glaucoma patients are undiagnosed and present late in the course of their disease. This can lead to irreversible vision loss, reduced quality of life, and a higher socioeconomic burden. Selection of therapeutic approaches for glaucoma should be based on careful ocular examination, patient medical history, presence of comorbidities, and awareness of concomitant systemic therapies. Therapy should also be individualized to patients' needs and preferences. Recent developments in this therapeutic field require revisiting treatment algorithms and integration of traditional and novel approaches in order to ensure optimal visual outcomes. This article provides an overview of recent developments and practice trends in the medical management of glaucoma in Canada. A discussion of the surgical management is beyond the scope of this paper.

Steady-state pattern electroretinogram and frequency doubling technology in anisometropic amblyopia

Background

Steady-state pattern electroretinogram (PERG) and frequency doubling technology (FDT) perimetry can be used to selectively investigate the activity of the M-Y ganglion cells in adult anisometropic amblyopes.

Methods

Fifteen normal subjects (mean 27.8±4.1 years) and 15 adults with anisometropic amblyopia (mean 28.7±5.9 years) were analyzed using steady-state PERG and FDT.

Results

The amplitude of steady-state PERG was significantly different not only among the control group and both the amblyopic eye (P=0.0001) and the sound eye group (P=0.0001), but also between the latter two groups (P=0.006). The difference in FDT mean deviation was statistically significant not only between the control group and amblyopic eye group (P=0.0002), but also between the control group and the sound eye group (P=0.0009). The FDT pattern standard deviation was significantly higher in the control group rather than in the amblyopic eye (P=0.0001) or the sound eye group (P=0.0001). A correlation was found between the reduction in PERG amplitude and the increase in FDT-pattern standard deviation index not only in amblyopic (P=0.0025) and sound (P=0.0023) eyes, but also in the healthy control group (P=0.0001).

Conclusion

These data demonstrate that in anisometropic amblyopia, there is an abnormal functionality of a subgroup of the magnocellular ganglion cells (M-Y), and the involvement of these cells, together with the parvocellular pathway, may play a key role in the clinical expression of the disease.

Primary open-angle glaucoma

Glaucoma is an optic neuropathy that is characterized by the progressive degeneration of the optic nerve, leading to visual impairment. Glaucoma is the main cause of irreversible blindness worldwide, but typically remains asymptomatic until very severe. Open-angle glaucoma comprises the majority of cases in the United States and western Europe, of which, primary open-angle glaucoma (POAG) is the most common type. By contrast, in China and other Asian countries, angle-closure glaucoma is highly prevalent. These two types of glaucoma are characterized based on the anatomic configuration of the aqueous humour outflow pathway. The pathophysiology of POAG is not well understood, but it is an optic neuropathy that is thought to be associated with intraocular pressure (IOP)-related damage to the optic nerve head and resultant loss of retinal ganglion cells (RGCs). POAG is generally diagnosed during routine eye examination, which includes fundoscopic evaluation and visual field assessment (using perimetry). An increase in IOP, measured by tonometry, is not essential for diagnosis. Management of POAG includes topical drug therapies and surgery to reduce IOP, although new therapies targeting neuroprotection of RGCs and axonal regeneration are under development.

Structural and Functional Evaluations for the Early Detection of Glaucoma

The early detection of glaucoma is imperative in order to preserve functional vision. Structural and functional methods are utilized to detect and monitor glaucomatous damage and the vision loss it causes. The relationship between these detection measures is complex and differs between individuals, especially in early glaucoma. Using both measures together is advised in order to ensure the highest probability of glaucoma detection, and new testing methods are continuously developed with the goals of earlier disease detection and improvement of disease monitoring. The purpose of this review is to explore the relationship between structural and functional glaucoma detection and discuss important technological advances for early glaucoma detection.

The Prevalence of Open-Angle Glaucoma by Age in Myopia: The Korea National Health and Nutrition Examination Survey

PURPOSE

To investigate the prevalence of open-angle glaucoma (OAG) in myopia by age.

MATERIALS AND METHODS

A cross-sectional study using a stratified, multistage, probability cluster survey. Participants in the Korean National Health and Nutrition Examination Survey between 2010 and 2011 were included. A standardized protocol was used to interview every participant and perform comprehensive ophthalmic examinations. Glaucoma was diagnosed according to the International Society of Geographical and Epidemiological Ophthalmology (ISGEO) criteria.

RESULTS

After adjusting for age and sex, there was a positive correlation between OAG prevalence and increasing myopic refractive error except in participants with hyperopia. Younger participants with higher myopic refractive error had higher OAG prevalence than older participants with lower myopic refractive error. Participants with high myopia (OR 3.90, 95% confidence interval (CI) 2.30-6.59) had significantly greater age- and sex-adjusted odd ratios (ORs) than did those with emmetropia who were younger than 60 years.

CONCLUSIONS

These data suggest that OAG develops earlier in participants with high myopia than in others. There was a high prevalence of OAG in participants with high myopia, even in those 19-29 years of age. Therefore, OAG screening should be performed earlier in participants with high myopia than is suggested by traditional guidelines.

Baseline factors predicting the risk of conversion from ocular hypertension to primary open-angle glaucoma during a 10-year follow-up

PurposeTo evaluate the ability of baseline clinical, morphological, and functional factors to predict the conversion to primary open-angle glaucoma (POAG) in ocular hypertensive (OHT) patients.MethodsThis single-center prospective longitudinal observational study included 116 eyes of 116 OHT patients followed for a 10-year period. All patients had intraocular pressure (IOP) ≥24 mm Hg in one eye and >21 mm Hg in the other eye, normal visual fields (VFs) and normal optic disc (OD) appearance in both eyes at baseline. All OHT patients were untreated at baseline with subsequent treatment upon need according to clinical judgement. Only one eye per subject was randomly selected. Patient age, gender, IOP, central corneal thickness (CCT), and ibopamine test results were collected at baseline. All patients underwent standard automated perimetry, short-wavelength automated perimetry (SWAP), frequency-doubling technology, confocal scanning laser ophthalmoscopy (CSLO), and scanning laser polarimetry (SLP) at baseline and every 6 months thereafter. Main outcome measure was the conversion to POAG, defined as the development of reproducible VF and/or OD abnormalities attributable to glaucoma. Cox proportional hazards models were used to identify the baseline factors predictive of POAG conversion.ResultsDuring the 10-year follow-up, 25% of eyes converted to POAG. In multivariate Cox models, baseline factors that were significant predictors of POAG development included: older age (hazard ratio (HR) 1.0, 99% confidence intervals (CIs) 1.0-1.2, per 1 year older); SWAP Glaucoma Hemifield test 'outside normal limits' (HR 4.3, 99% CIs 1.2-17.9); greater SLP 'Inter-eye Symmetry' (HR 1.1, 99% CIs 0.4-3.0, per 1 unit lower); lower CSLO Rim Volume (HR 1.1, 99% CIs 0.3-3.2, per 0.1 mm(3) lower); and greater CSLO cup-to-disc ratio (HR 6.0, 99% CIs 3.6-16.8, per 0.1 unit greater).ConclusionsThe baseline parameters that proved to be useful in assessing the likelihood of an OHT patient to develop POAG included age, functional variables provided by SWAP, and structural variables provided by SLP and CSLO. In this cohort of patients, baseline IOP, CCT, and ibopamine provocative test results were not significant predictors of POAG conversion.

Ophthalmic markers of the diabetic polyneuropathy

In the article, a world literature analysis is presented on the relationship between structural and functional changes of the retina and of the optic nerve and the diabetic polyneuropathy severity degree. Diabetic polyneuropathy is one of the most common and severe complications of diabetes mellitus leading in many patients to ulcer formation and to foot amputation. Modern methods for neuropathy diagnosis either do not allow revealing early stage changes, or include invasive procedures. Ophthalmologists, involved in diabetic patients care, due to objective reasons focus on diabetic retinopathy. However, the evidence that the corneal nerves state is a marker of peripheral neuropathy suggests a new and very important role of the ophthalmologist in diabetic patient care. Several studies obtained promising results about structural and functional retinal changes could be found in diabetic patients before retinopathy start; this allows to suggest the neuropathy role at their origin.

Comparison of Standard Automated Perimetry, Short-Wavelength Automated Perimetry, and Frequency-Doubling Technology Perimetry to Monitor Glaucoma Progression

Detection of progression is paramount to the clinical management of glaucoma. Our goal is to compare the performance of standard automated perimetry (SAP), short-wavelength automated perimetry (SWAP), and frequency-doubling technology (FDT) perimetry in monitoring glaucoma progression.Longitudinal data of paired SAP, SWAP, and FDT from 113 eyes with primary open-angle glaucoma enrolled in the Diagnostic Innovations in Glaucoma Study or the African Descent and Glaucoma Evaluation Study were included. Data from all tests were expressed in comparable units by converting the sensitivity from decibels to unitless contrast sensitivity and by expressing sensitivity values in percent of mean normal based on an independent dataset of 207 healthy eyes with aging deterioration taken into consideration. Pointwise linear regression analysis was performed and 3 criteria (conservative, moderate, and liberal) were used to define progression and improvement. Global mean sensitivity (MS) was fitted with linear mixed models.No statistically significant difference in the proportion of progressing and improving eyes was observed across tests using the conservative criterion. Fewer eyes showed improvement on SAP compared to SWAP and FDT using the moderate criterion; and FDT detected less progressing eyes than SAP and SWAP using the liberal criterion. The agreement between these test types was poor. The linear mixed model showed a progressing trend of global MS overtime for SAP and SWAP, but not for FDT. The baseline estimate of SWAP MS was significantly lower than SAP MS by 21.59% of mean normal. FDT showed comparable estimation of baseline MS with SAP.SWAP and FDT do not appear to have significant benefits over SAP in monitoring glaucoma progression. SAP, SWAP, and FDT may, however, detect progression in different glaucoma eyes.

Combining Frequency Doubling Technology Perimetry and Scanning Laser Polarimetry for Glaucoma Detection

PURPOSE

To determine the ability of frequency doubling technology (FDT) and scanning laser polarimetry with variable corneal compensation (GDx-VCC) to detect glaucoma when used individually and in combination.

METHODS

One hundred ten normal and 114 glaucomatous subjects were tested with FDT C-20-5 screening protocol and the GDx-VCC. The discriminating ability was tested for each device individually and for both devices combined using GDx-NFI, GDx-TSNIT, number of missed points of FDT, and normal or abnormal FDT. Measures of discrimination included sensitivity, specificity, area under the curve (AUC), Akaike's information criterion (AIC), and prediction confidence interval lengths.

RESULTS

For detecting glaucoma regardless of severity, the multivariable model resulting from the combination of GDx-TSNIT, number of abnormal points on FDT (NAP-FDT), and the interaction GDx-TSNIT×NAP-FDT (AIC: 88.28, AUC: 0.959, sensitivity: 94.6%, specificity: 89.5%) outperformed the best single-variable model provided by GDx-NFI (AIC: 120.88, AUC: 0.914, sensitivity: 87.8%, specificity: 84.2%). The multivariable model combining GDx-TSNIT, NAP-FDT, and interaction GDx-TSNIT×NAP-FDT consistently provided better discriminating abilities for detecting early, moderate, and severe glaucoma than the best single-variable models.

CONCLUSIONS

The multivariable model including GDx-TSNIT, NAP-FDT, and the interaction GDx-TSNIT×NAP-FDT provides the best glaucoma prediction compared with all other multivariable and univariable models. Combining the FDT C-20-5 screening protocol and GDx-VCC improves glaucoma detection compared with using GDx or FDT alone.

Strategies to improve early diagnosis in glaucoma

Early diagnosis and treatment of glaucoma is important to reduce the risk of progressive and irreversible visual loss. The key to diagnosis is recognition of morphological changes to the optic nerve head and retinal nerve fiber layer, but in some patients, functional abnormalities are detected first. This review describes recent innovations with the potential to improve the early detection of glaucoma. Developments in imaging include novel optic nerve head metrics such as Bruch's membrane opening-minimum rim width, enhanced ability to quantify inner layers of the glaucomatous macula, and ability to image deep optic nerve head structures, including the lamina cribrosa. Developments in detection of early glaucomatous functional loss include novel perimetric tests using frequency-doubling technology and flicker-defined form stimuli. Methods to combine results of structural and functional assessments are also presented that may improve early detection of glaucoma.

Frequency Doubling Technology Perimetry and Changes in Quality of Life of Glaucoma Patients: A Longitudinal Study

PURPOSE

To evaluate the relationship between rates of change on frequency doubling technology (FDT) perimetry and longitudinal changes in quality of life (QoL) of glaucoma patients.

DESIGN

Prospective observational cohort study.

METHODS

One hundred fifty-two subjects (127 glaucoma and 25 healthy) were followed for an average of 3.2 ± 1.1 years. All subjects were evaluated with National Eye Institute Visual Function Questionnaire (NEI VFQ-25), FDT, and standard automated perimetry (SAP). Glaucoma patients had a median of 3 NEI VFQ-25, 8 FDT, and 8 SAP tests during follow-up. Mean sensitivities of the integrated binocular visual fields were estimated for FDT and SAP and used to calculate rates of change. A joint longitudinal multivariable mixed model was used to investigate the association between change in binocular mean sensitivities and change in NEI VFQ-25 Rasch-calibrated scores.

RESULTS

There was a statistically significant correlation between change in binocular mean sensitivity for FDT and change in NEI VFQ-25 scores during follow-up in the glaucoma group. In multivariable analysis with the confounding factors, each 1 dB/year change in binocular FDT mean sensitivity corresponded to a change of 0.8 units per year in the NEI VFQ-25 scores (P = .001). For binocular SAP mean sensitivity, each 1 dB/year change was associated with 2.4 units per year change in NEI VFQ-25 scores (P < .001). The multivariable model containing baseline and rate of change information from SAP had stronger ability to predict change in NEI VFQ-25 scores compared to the equivalent model for FDT (R(2) of 50% and 30%, respectively; P = .001).

CONCLUSION

SAP performed significantly better than FDT in predicting change in NEI VFQ-25 scores in our population, suggesting that it may still be the preferable perimetric technique for predicting risk of disability from the disease.

Selecting visual field tests and assessing visual field deterioration in glaucoma

Testing the peripheral field of vision is the mainstay for detection of glaucoma deterioration. Various methods and algorithms are currently available for detection of early glaucoma or establishing disease progression. Alternative testing strategies such as frequency doubling technology perimetry or short-wavelength automated perimetry have been extensively explored over the last 2 decades. The former has been found most promising for detection of earliest evidence of functional glaucoma damage when the standard achromatic perimetry results are still within the normal range. However, standard achromatic perimetry remains the standard technique for establishing deterioration of the disease. Both trend and event analyses are used for establishing change within series of visual fields. Trend analyses provide the clinician with rates of progression, putting the speed of glaucoma progression in the context of patient longevity, whereas event analyses demonstrate a "step" change regardless of the length of time it took for this amount of change to occur. The two techniques are complementary and should be used concurrently.

Long-term follow-up in preperimetric open-angle glaucoma: progression rates and associated factors

PURPOSE

To investigate the rate of progressive visual field (VF) loss and associated factors for structural or functional progression in preperimetric open-angle glaucoma (OAG).

DESIGN

Longitudinal, observational study.

METHODS

We included 127 eyes of 127 preperimetric OAG patients who were treated with topical medication and followed for more than 5 years. All patients underwent stereo optic disc photography, red-free retinal nerve fiber layer (RNFL) photography, frequency doubling technology perimetry, and standard automated perimetry (SAP). Progression was defined as a structural (glaucomatous change confirmed by stereo optic disc and red-free RNFL photography) or functional (new glaucomatous defect on SAP) deterioration. The progression rate of SAP mean deviation (dB/year) and factors associated with progression were evaluated.

RESULTS

Glaucoma progression was detected in 72 of 127 eyes (56.7%). Mean rate of VF progression was -0.39 ± 0.64 dB/year in all patients; -0.66 ± 0.60 dB/year in progressors and -0.03 ± 0.24 dB/year in nonprogressors. A multivariate Cox proportional hazard model revealed that optic disc hemorrhage (hazard ratio [HR] = 1.718, P = .031) and the percentage reduction in intraocular pressure (IOP; HR = 0.964, P = .002) were significantly associated with disease progression. Patients with disc hemorrhage had a greater cumulative probability of progression than those without disc hemorrhage (P = .014 by log-rank test).

CONCLUSIONS

Our results support the importance of lowering IOP, even at the preperimetric stage. Preperimetric glaucoma patients with disc hemorrhage and insufficient IOP control should be carefully monitored for greater risk of progression.