Anatomical Features can Affect OCT Measures Used for Clinical Decisions and Clinical Trial Endpoints.

Purpose: To understand the association between anatomical parameters of healthy eyes and optical coherence tomography (OCT) circumpapillary retinal nerve fiber layer (cpRNFL) thickness measurements. Methods: OCT cpRNFL thickness was obtained from 396 healthy eyes in a commercial reference database (RDB). The temporal quadrant (TQ), superior quadrant (SQ), inferior quadrant (IQ), and global (G) cpRNFL thicknesses were analyzed. The commercial OCT devices code these values based on percentiles (red, <1%; yellow, ≥1% and <5%), after taking age and disc area into consideration. Four anatomical parameters were assessed: fovea-to-disc distance, an estimate of axial length, and the locations of the superior and the inferior peaks of the cpRNFL thickness curve. Pearson correlation values were obtained for the parameters and the thickness measures of each of the four cpRNFL regions, and t-tests were performed between the cpRNFL thicknesses coded as abnormal (red or yellow, <5%) versus normal (≥5%). Results: For each of the four anatomical parameters, the correlation with the thickness of one or more of the TQ, SQ, IQ, and G regions exceeded the correlation with age or disc area. All four parameters were significantly (P < 0.001) associated with the abnormal cpRNFL values. The significant parameters were not the same for the different regions; for example, a parameter could be negatively correlated for the TQ but positively correlated with the SQ or IQ. Conclusions: In addition to age and disc area, which are used for inferences in normative databases, four anatomical parameters are associated with cpRNFL thickness. Translational Relevance: Taking these additional anatomical parameters into consideration should aid diagnostic accuracy.

Frequency of Optical Coherence Tomography Testing to Detect Progression in Glaucoma.

PRCIS: With high specificity and less variability than perimetry, more frequent testing resulted in shorter time to detect progression, though a 6-month testing interval provides a reasonable trade-off for following glaucoma patients using optical coherence tomography (OCT). PURPOSE: To investigate the time to detect progression in glaucomatous eyes using different OCT test intervals. MATERIALS AND METHODS: Participants with manifest glaucoma from the African Descent and Glaucoma Evaluation Study (ADAGES), a multicenter, prospective, observational cohort study, were included. A total of 2699 OCT tests from 171 glaucomatous and 149 normal eyes of 182 participants, with at least 5 tests and 2 years of follow-up, were analyzed. Computer simulations (n=10,000 eyes) were performed to estimate time to detect progression of global circumpapillary retinal nerve fiber layer thickness (cpRNFL) measured with OCT tests. Simulations were based on different testing paradigms (every 4, 6, 12, and 24 mo) and different rates of change (µm/year). Time to detect significant progression ( P <0.05) at 80% and 90% power were calculated for each paradigm and rate of cpRNFL change. RESULTS: As expected, more frequent testing resulted in shorter time to detect progression. Although there was clear disadvantage for testing at intervals of 24 versus 12 months (~22.4% time [25 mo] increase in time to progression detection) and when testing 12 versus 6 months (~22.1% time [20 mo] increase), the improved time to detect progression was less pronounced when comparing 6 versus 4 months (~11.5% time [10 mo] reduction). CONCLUSION: With high specificity and less variability than perimetry, a 6-month testing interval provides a reasonable trade-off for following glaucoma patients using OCT.

Detecting glaucoma with only OCT: Implications for the clinic, research, screening, and AI development.

A method for detecting glaucoma based only on optical coherence tomography (OCT) is of potential value for routine clinical decisions, for inclusion criteria for research studies and trials, for large-scale clinical screening, as well as for the development of artificial intelligence (AI) decision models. Recent work suggests that the OCT probability (p-) maps, also known as deviation maps, can play a key role in an OCT-based method. However, artifacts seen on the p-maps of healthy control eyes can resemble patterns of damage due to glaucoma. We document in section 2 that these glaucoma-like artifacts are relatively common and are probably due to normal anatomical variations in healthy eyes. We also introduce a simple anatomical artifact model based upon known anatomical variations to help distinguish these artifacts from actual glaucomatous damage. In section 3, we apply this model to an OCT-based method for detecting glaucoma that starts with an examination of the retinal nerve fiber layer (RNFL) p-map. While this method requires a judgment by the clinician, sections 4 and 5 describe automated methods that do not. In section 4, the simple model helps explain the relatively poor performance of commonly employed summary statistics, including circumpapillary RNFL thickness. In section 5, the model helps account for the success of an AI deep learning model, which in turn validates our focus on the RNFL p-map. Finally, in section 6 we consider the implications of OCT-based methods for the clinic, research, screening, and the development of AI models.

The Effect of Ametropia on Glaucomatous Visual Field Loss.

Myopia has been discussed as a risk factor for glaucoma. In this study, we characterized the relationship between ametropia and patterns of visual field (VF) loss in glaucoma. Reliable automated VFs (SITA Standard 24-2) of 120,019 eyes from 70,495 patients were selected from five academic institutions. The pattern deviation (PD) at each VF location was modeled by linear regression with ametropia (defined as spherical equivalent (SE) starting from extreme high myopia), mean deviation (MD), and their interaction (SE × MD) as regressors. Myopia was associated with decreased PD at the paracentral and temporal VF locations, whereas hyperopia was associated with decreased PD at the Bjerrum and nasal step locations. The severity of VF loss modulated the effect of ametropia: with decreasing MD and SE, paracentral/nasal step regions became more depressed and Bjerrum/temporal regions less depressed. Increasing degree of myopia was positively correlated with VF depression at four central points, and the correlation became stronger with increasing VF loss severity. With worsening VF loss, myopes have increased VF depressions at the paracentral and nasal step regions, while hyperopes have increased depressions at the Bjerrum and temporal locations. Clinicians should be aware of these effects of ametropia when interpreting VF loss.

Patient Concerns Regarding Suspended Ophthalmic Care Due to COVID-19.

PURPOSE: The temporary cessation and profound changes in ophthalmic care delivery that occurred as a result of the coronavirus disease 2019 (COVID-19) pandemic have yet to be fully understood. Our objective is to assess patients' self-reported impact of health care lockdown measures on their fears and anxieties during the crisis period of the COVID-19 pandemic in New York City. METHODS: We conducted a digital, self-reported, patient care survey distributed by an e-mail at Columbia University's Department of Ophthalmology outpatient faculty practice. Inclusion criteria were age greater than or equal to 18 years, a diagnosis of either retinal disease or glaucoma, and a canceled or rescheduled ophthalmology established patient appointment during the acute phase of the COVID-19 pandemic in New York City. Patients without an e-mail address listed in their electronic medical records were excluded. The survey occurred between March 2, 2020, to May 30, 2020. Primary measures were survey responses to assess key areas of patient anxiety or concern during the pandemic including the safety of care delivery in a COVID pandemic, difficulties contacting or being seen by their ophthalmologist, concern of vision loss or disease progression, and concern over missed or access to treatments. Secondary measures were correlating survey response to factors such as visual acuity, intraocular pressure, diagnosis, disease severity, follow-up urgency, recent treatments, and diagnostic testing data. RESULTS: Of the 2594 surveys sent out, 510 (19.66%) were completed. Over 95% of patients were at least as concerned as in normal circumstances about their ocular health during the peak of the pandemic. Overall, 76% of respondents were more concerned than normal that they could not be seen by their ophthalmologist soon enough. Increased concern over ocular health, disease progression, and access to care all showed positive correlations (P<0.05) with worse disease severity as measured with testing such as visual fields and optical coherence tomography. In addition, 55% of patients were afraid of contracting COVID-19 during an office visit. CONCLUSION AND RELEVANCE: We found a majority of our patients were concerned about limitations in access to ophthalmic care and were fearful of disease progression. In addition, we found a number of demographic and clinical factors that correlated with increased anxiety in our patients.

The Challenge of Managing Bilateral Acute Angle-closure Glaucoma in the Presence of Active SARS-CoV-2 Infection.

PURPOSE: To report a case of bilateral acute angle-closure glaucoma associated with hyponatremia in the setting of chlorthalidone use and SARS-CoV-2 infection, and to demonstrate the challenges of managing this patient given her infectious status. METHODS: This was a case report. CASE: A 65-year-old woman taking chlorthalidone for hypertension presented to the emergency room with headache, pain, and blurry vision in both eyes and was found to be in bilateral acute angle closure. On laboratory investigation, she was severely hyponatremic and also tested positive for SARS-CoV-2. B-scan ultrasound demonstrated an apparent supraciliary effusion in the right eye. Following stabilization of her intraocular pressures with medical management, she ultimately underwent cataract extraction with iridectomies and goniosynechiolysis in both eyes. CONCLUSIONS: We report a rare case of bilateral acute angle-closure glaucoma associated with hyponatremia. Chlorthalidone use and perhaps SARS-CoV-2 infection may have contributed to this electrolyte abnormality and unique clinical presentation. In addition, we discuss the challenges of managing this complex patient with active SARS-CoV-2 infection during the pandemic.

Did the OCT Show Progression Since the Last Visit?

Identifying progression is of fundamental importance to the management of glaucoma. It is also a challenge. The most sophisticated, and probably the most useful, commercially available clinical tool for identifying progression is the Guided Progression Analysis (GPA), which was initially developed to identify progression using 24-2 visual field tests. More recently, it has been extended to retinal nerve fiber layer (RNFL) and ganglion cell+inner plexiform layer thicknesses measured with optical coherence tomography (OCT). However, the OCT GPA requires a minimum of 3 tests to determine "possible loss (progression)" and a minimum of 4 tests to determine if the patient shows "likely loss (progression)." Thus, it is not designed to answer a fundamental question asked by both the clinician and the patient, namely: Did damage progress since the last visit? Some clinicians use changes in summary statistics, such as global/average circumpapillary RNFL thickness. However, these statistics have poor sensitivity and specificity due to segmentation and alignment errors. Instead of relying on the GPA analysis or summary statistics, one needs to evaluate RNFL and ganglion cell+inner plexiform layer probability maps and circumpapillary OCT B-scan images. In addition, we argue that the clinician can make a better decision about suspected progression between 2 test days by topographically comparing the changes in the different OCT maps and images, in addition to topographically comparing the changes in the visual field with the changes in OCT probability maps.

Optical Coherence Tomography Can Be Used to Assess Glaucomatous Optic Nerve Damage in Most Eyes With High Myopia.

PRECIS: It is generally assumed that optical coherence tomography (OCT) cannot be used to diagnose glaucomatous optic neuropathy (GON) in high myopes. However, this study presents evidence that there is sufficient information in OCT scans to allow for accurate diagnosis of GON in most eyes with high myopia. PURPOSE: The purpose of this study was to test the hypothesis that glaucomatous damage can be accurately diagnosed in most high myopes via an assessment of the OCT results. PATIENTS AND METHODS: One hundred eyes from 60 glaucoma patients or suspects, referred for OCT scans and evaluation, had corrected spherical refractive errors worse than -6 D and/or axial lengths ≥26.5 mm. An OCT specialist judged whether the eye had GON, based upon OCT circle scans of the disc and cube scans centered on the macula. A glaucoma specialist made the same judgement using all available information (eg, family history, repeat visits, intraocular pressure, 10-2 and 24-2 visual fields, OCT). A reference standard was created based upon the glaucoma specialist's classifications. In addition, the glaucoma specialist judged whether the eyes had peripapillary atrophy (PPA), epiretinal membrane (ERM), tilted disc (TD), and/or a paravascular inner retinal defect (PIRD). RESULTS: The OCT specialist correctly identified 97 of the 100 eyes using the OCT information. In 63% of the cases, the inner circle scan alone was sufficient. For the rest, additional scans were requested. In addition, 81% of the total eyes had: PPA (79%), ERM (18%), PIRD (26%), and/or TD (48%). CONCLUSIONS: For most eyes with high myopia, there is sufficient information in OCT scans to allow for accurate diagnosis of GON. However, the optimal use of the OCT will depend upon training to read OCT scans, which includes taking into consideration myopia related OCT artifacts and segmentation errors, as well as PPA, ERM, PIRD, and TD.

Monitoring Glaucomatous Functional Loss Using an Artificial Intelligence-Enabled Dashboard.

PURPOSE: To develop an artificial intelligence (AI) dashboard for monitoring glaucomatous functional loss. DESIGN: Retrospective, cross-sectional, longitudinal cohort study. PARTICIPANTS: Of 31 591 visual fields (VFs) on 8077 subjects, 13 231 VFs from the most recent visit of each patient were included to develop the AI dashboard. Longitudinal VFs from 287 eyes with glaucoma were used to validate the models. METHOD: We entered VF data from the most recent visit of glaucomatous and nonglaucomatous patients into a "pipeline" that included principal component analysis (PCA), manifold learning, and unsupervised clustering to identify eyes with similar global, hemifield, and local patterns of VF loss. We visualized the results on a map, which we refer to as an "AI-enabled glaucoma dashboard." We used density-based clustering and the VF decomposition method called "archetypal analysis" to annotate the dashboard. Finally, we used 2 separate benchmark datasets-one representing "likely nonprogression" and the other representing "likely progression"-to validate the dashboard and assess its ability to portray functional change over time in glaucoma. MAIN OUTCOME MEASURES: The severity and extent of functional loss and characteristic patterns of VF loss in patients with glaucoma. RESULTS: After building the dashboard, we identified 32 nonoverlapping clusters. Each cluster on the dashboard corresponded to a particular global functional severity, an extent of VF loss into different hemifields, and characteristic local patterns of VF loss. By using 2 independent benchmark datasets and a definition of stability as trajectories not passing through over 2 clusters in a left or downward direction, the specificity for detecting "likely nonprogression" was 94% and the sensitivity for detecting "likely progression" was 77%. CONCLUSIONS: The AI-enabled glaucoma dashboard, developed using a large VF dataset containing a broad spectrum of visual deficit types, has the potential to provide clinicians with a user-friendly tool for determination of the severity of glaucomatous vision deficit, the spatial extent of the damage, and a means for monitoring the disease progression.

Baseline Age and Mean Deviation Affect the Rate of Glaucomatous Vision Loss.

PURPOSE: The purpose of this study was to assess the relationship between the rate of the glaucomatous visual field (VF) worsening and baseline age and baseline VF mean deviation (MD). DESIGN: This study was a retrospective, multisite cohort. PARTICIPANTS: A total of 84,711 reliable Swedish Interactive Thresholding Algorithm 24-2 VF tests from 8167 eyes from 5644 patients with ≥6 VF tests, ≥5 years of follow-up, baseline age 18 years or above and baseline MD ≥-10 dB, and at least 2 abnormal VF tests were included from the Glaucoma Research Network Database. METHODS: The global mean deviation rates (MDRs) and pointwise total deviation rates (TDRs) of VF progression (dB/y) were calculated for each eye using linear regression. The relationships between MDR and baseline age and MD were determined using linear mixed-effects models and logistic regression, with rapid progression defined as an MDR≤-1.0 dB/y. The relationships between TDR and baseline age and baseline MD were determined using linear mixed-effects models. MAIN OUTCOME MEASURES: Coefficients of the regression models. RESULTS: In individual mixed-effects models both baseline age (ß=-0.0079 dB/y; P<0.001) and baseline MD (ß=0.012/y; P<0.001) were associated with faster progression. All parameters were statistically significant in the full model with both parameters and their interaction (ß=0.00065; P=0.0017) as covariates. With logistic regression, each year increase in baseline age increased the odds of belonging to the rapid-progressing group by a factor of 1.033, and each unit increase in baseline MD (less severe visual loss) decreased the odds by a factor of 0.8821. The mean pointwise TDR ranged from -0.21 to -0.55 dB/y, with the most rapid pointwise progression observed in the nasal and paracentral regions of the field. CONCLUSIONS: Older age and worse MD at baseline are associated with more rapid VF progression in this large dataset. The effect of age on MDR is influenced by baseline MD severity, supporting the importance of early detection and more aggressive therapy in older patients with worse VF damage. The pointwise rate of VF loss varies across the VF, providing a means for physicians to more effectively monitor progression.

Structure-Function Agreement Is Better Than Commonly Thought in Eyes With Early Glaucoma.

Purpose: To assess the agreement between structural (optical coherence tomography [OCT]) and functional (visual field [VF]) glaucomatous damage with an automated method and deviation/probability maps, and to compare this method to a metric method. Methods: Wide-field spectral-domain OCT scans, including the disc and macula, and 24-2 and 10-2 VFs were obtained from 45 healthy control (H) eyes/individuals, and 53 eyes/patients with 24-2 mean deviation (MD) better than -6 dB diagnosed as "definite glaucoma" (DG) by experts. Abnormal structure-abnormal function (aS-aF) agreement was assessed with an automated topographic (T) method based upon VF pattern deviation and OCT probability maps. Results were compared to a metric (M) method optimized for accuracy, (abnormal 24-2 glaucoma hemifield test [GHT] or pattern standard deviation [PSD], or 10-2 PSD AND abnormal OCT [quadrant]). Results: For the T-method, 47 (88.7%) of the 53 DG eyes showed aS-aF agreement, compared to 2 (4.5%) of the 45 H eyes. The aS-aF agreement for these two H eyes was easily identified as mistaken, and did not replicate on a subsequent test. Without the 10-2, the aS-aF agreement decreased from 47 to 34 (64.2%) of 53 DG eyes. For the M-method, 37 (69.8%) of the 53 DG eyes showed aS-aF agreement, while omitting the 10-2 VF resulted in agreement in only 33 (62.3%) eyes. Conclusions: There is good agreement between structural and functional damage, even in eyes with confirmed early glaucomatous damage, if both 24-2 and 10-2 VFs are obtained, and abnormal locations on the VFs are compared to abnormal regions seen on OCT macular and disc scans. This can be done in an objective, automated fashion. (ClinicalTrials.gov number, NCT02547740.).

An Examination of the Frequency of Paravascular Defects and Epiretinal Membranes in Eyes With Early Glaucoma Using En-face Slab OCT Images.

PURPOSE: To examine the frequency of paravascular defects (PDs) and macular epiretinal membranes (ERMs) in eyes categorized as having mild glaucoma or glaucoma suspect using en-face slab analysis of optical coherence tomography (OCT) scans. MATERIALS AND METHODS: Fifty-seven glaucomatous eyes, 44 low-risk suspect eyes, and 101 healthy control eyes were included in the study. The 101 glaucomatous and suspect eyes had a mean deviation better than -6 dB on the 24-2 visual field, and a spherical refractive error between±6 D or axial length <26.5 mm. Two OCT-graders masked to eye classification identified ERMs and PDs on en-face slab images of the macula and peripapillary retina using horizontal B-scans and derived vertical B-scans. RESULTS: Glaucomatous eyes had a significantly higher number of PDs and ERMs than healthy controls (PD, P<0.001; ERM, P=0.046) and low-risk glaucoma suspects (PD, P=0.004; ERM, P=0.043). PDs and/or ERMs were present in 16 of 57 (28.1%) glaucomatous eyes, 2 of 44 (4.5%) suspect eyes, and 3 of 101 (3.0%) control eyes. Further, PDs were present in 11 of the 57 (19.3%) glaucomatous eyes, 1 of the 44 (2.3%) suspect eyes and 0 of the 101 (0%) control eyes, ERMs were seen in 7 of the 57 (12.3%) glaucomatous eyes, 1 of the 44 (2.3%) suspects, and 3 of the 101 (3.0%) control eyes. CONCLUSIONS: Eyes with early glaucoma have a higher frequency of PDs and ERMs than suspects or controls and exhibit PDs even in the absence of ERMs or high myopia.

The Effect of Therapeutic IOP-lowering Interventions on the 24-hour Ocular Dimensional Profile Recorded With a Sensing Contact Lens.

PRéCIS:: The 24-hour ocular dimensional profile recorded by a contact lens sensor was affected by intraocular pressure lowering interventions. Among different treatments, incisional surgery had the most significant effect. PURPOSE: We investigated the effect of different intraocular pressure (IOP)-lowering interventions on contact lens sensor (CLS) parameters and their relationship with Goldmann applanation tonometry (GAT)-measured IOP reduction. METHODS: Data from reliable CLS recordings performed before and after IOP-lowering interventions were analyzed. Three interventions were evaluated: topical medications, laser trabeculoplasty, and incisional surgery. A set of 115 different CLS parameters were derived from 24-hour curves. We compared before versus after values for each parameter. In addition, linear regression was performed using the percentage change of each CLS parameter as the outcome variable and the type of IOP-lowering procedure as the predictor after adjusting age and race. Finally, we investigated the relationship between changes in CLS parameters and GAT IOP with the Spearman rank correlation coefficient. RESULTS: A total of 182 eyes of 182 patients were included in the analyses: 60 (33%) topical medications, 69 (38%) laser, and 53 (29%) surgery. The mean GAT IOP change was 3.6±6.5 mm Hg (P<0.001). Overall, more CLS parameters had a significant change after surgery than in the other groups (surgery>laser=drug). Linear regression showed that, for 20 CLS parameters, surgery was the most predictive of greatest percentage change in CLS signals. In all, 11 (9.5%) of the CLS parameters were significantly correlated with GAT changes. CONCLUSIONS: Incisional glaucoma surgery had a more pronounced effect on GAT and CLS parameters than laser and drugs. The CLS can detect changes in patterns resulting from IOP-lowering interventions beyond daytime GAT IOP. This device could potentially be used to assess treatment efficacy in glaucoma.

Greater Physical Activity Is Associated with Slower Visual Field Loss in Glaucoma.

PURPOSE: To determine the association between physical activity levels and the rate of visual field (VF) loss in glaucoma. DESIGN: Longitudinal, observational study. PARTICIPANTS: Older adults with suspect or manifest glaucoma. METHODS: Participants wore accelerometers for 1 week to define average steps per day, minutes of moderate-to-vigorous activity, and minutes of nonsedentary activity. All available VF measurements before and after physical activity assessment were retrospectively analyzed to measure rates of VF loss. MAIN OUTCOME MEASURES: Pointwise changes in VF sensitivity associated with physical activity measures. RESULTS: A total of 141 participants (mean age, 64.9±5.8 years) were enrolled. Eye mean deviation (MD) at the time of physical activity assessment was -6.6 decibels (dB), and average steps per day were 5613±3158. The unadjusted average rate of VF loss as measured by pointwise VF sensitivity was 0.36 dB/year (95% confidence interval, -0.37 to -0.35). In multivariable models, slower VF loss was observed for patients demonstrating more steps (+0.007 dB/year/1000 daily steps, P < 0.001), more moderate-to-vigorous activity (+0.003 dB/year/10 more minutes of moderate-to-vigorous activity per day, P < 0.001), and more nonsedentary activity (+0.007 dB/year/30 more minutes of nonsedentary time per day, P = 0.005). Factors associated with a faster rate of VF loss included older age, non-white race, glaucoma surgery, cataract surgery, and moderate baseline VF damage (-6 dB ≥ MD >-12 dB) as opposed to mild VF damage (MD >-6 dB). Similar associations between baseline accelerometer-measured physical activity and rates of VF loss were observed over other time periods (e.g., within 1, 3, and 5 years of activity assessment). CONCLUSIONS: Increased walking, greater time spent doing moderate-to-vigorous physical activity, and more time spent in nonsedentary activity were associated with slower rates of VF loss in a treated population of patients with glaucoma, with an additional 5000 daily steps or 2.6 hours of nonsedentary physical activity decreasing the average rate of VF loss by approximately 10%. Future prospective studies are needed to determine if physical activity can slow VF loss in glaucoma or if progressive VF loss results in activity restriction. If the former is confirmed, this would mark physical activity as a novel modifiable risk factor for preventing glaucoma damage.

Comparison of Intraocular Pressure Changes During the Water Drinking Test Between Different Fluid Volumes in Patients With Primary Open-angle Glaucoma.

PURPOSE: The main objective of this study was to compare the intraocular pressure (IOP) response during the water drinking test (WDT) performed with 800 mL, 1000 mL, and 10 mL/kg of body weight and to test its relationship with body mass index (BMI). METHODS: In this prospective, observer-masked, observational study, patients treated with primary open-angle glaucoma were evaluated. In group I, 29 consecutive patients with body weight ≤60 kg underwent an 800 mL fluid challenge followed by a second WDT session with 10 mL/kg of body weight no longer than 4 months apart. Group II included 30 consecutive patients with body weight >60 kg who underwent a 1000 mL fluid challenge followed by an 800 mL test no longer than 4 months apart. IOP was measured before (baseline) and after water ingestion every 15 minutes for 45 minutes. RESULTS: In group I, there was no significant difference in baseline or peak IOP between 800 mL and 10 mL/kg of body weight tests (P=0.12 and 0.56, respectively). However, 10 mL/kg tended to lead to consistently lower IOP values and a biased response in eyes with higher IOP. In group II, there was also no significant difference in baseline or peak IOP between 800 and 1000 mL tests (P=0.26 and 0.72, respectively). No biased response was observed in this group. There was no significant association between IOP peak and BMI with 800 mL (P=0.18), 10 mL/kg (P=0.29), or 1000 mL (P=0.34). CONCLUSIONS: There was overall good agreement between WDT results with different fluid volumes. The response to the volume loads tested in this study was not influenced by the BMI.

Four Questions for Every Clinician Diagnosing and Monitoring Glaucoma.

We pose 4 questions for the clinician diagnosing and monitoring glaucoma, and supply evidence-based answers. The first question is: "When do you perform a 10-2 (2-degree grid) visual field (VF) test?" We argue the best answer is: anyone you would do, or have done, a 24-2 (6-degree grid) VF on should have both a 24-2 and a 10-2 VF within the first 2 visits. Second, "When do you perform an optical coherence tomography (OCT) scan of the macula?" We argue that, if you are performing an OCT test, then it should include both the macula and disc, either as a single scan or as 2 scans, one centered on the macula and the other on the disc. Third, "How do you know if the VF and OCT tests agree?" The poor answer is, "I use summary statistics such as 24-2 mean deviation and global or quadrant average of retinal nerve fiber layer (RNFL) thickness." It is much better to topographically compare abnormal regions on the OCT to abnormal regions on the VF. Finally, the fourth question is: "When do you look at OCT images?" We argue that, at a minimum, the clinician should be directly examining an image of the circumpapillary RNFL, and this image should be sufficiently large and with sufficient resolution so that local damage can be seen, and the segmentation evaluated.

Macular and Multifocal PERG and FD-OCT in Preperimetric and Hemifield Loss Glaucoma.

PURPOSE: To evaluate the ability of macular and multifocal (mf) pattern electroretinogram (PERG) to differentiate preperimetric glaucoma (PG) and glaucoma with hemifield loss (GHL) from controls, to compare the discrimination ability of PERG and fourier-domain optical coherence tomography (FD-OCT), and to assess the relationship between measurements. PATIENTS AND METHODS: Standard automated perimetry, steady-state and transient PERG and mfPERG measurements were obtained from PG (n=14, 24 eyes), GHL (n=5, 7 eyes), and controls (n=19, 22 eyes). Circumpapillary retinal nerve fiber layer (cpRNFL), full-thickness macula, and segmented macular layer thicknesses on FD-OCT were investigated. Measurements were compared using mixed effects linear models. The relationships between measurements and the diagnostic performance of each technology were assessed. RESULTS: Compared with controls, average P50 peak time transient PERG responses were reduced in PG and GHL, whereas average latency and amplitude steady-state and mfPERG responses were abnormal only in GHL. cpRNFL and macular thickness measurements in PG and GHL differed significantly from controls. A significant relationship was found between PERG and most FD-OCT or SAP parameters. Partial least squares discriminant analysis revealed that OCT parameters, along with mfPERG and transient PERG parameters had similar ability to discriminate PG and GHL from healthy controls. CONCLUSIONS: PERG and OCT parameters may be abnormal, with significant correlations between measurements, in PG eyes. Both technologies may be useful for detection of early glaucoma.