Hazard Detection During Simulated Driving in Glaucoma Patients.

PRCIS: In this cross-sectional study, glaucoma patients showed slower reaction times (RTs) to hazardous situations when compared with control subjects during simulated driving. Worse RTs were associated with a greater magnitude of visual field loss. PURPOSE: The purpose of this study was to evaluate the impact of different hazardous traffic conditions on driving performance in glaucoma patients using a high-fidelity driving simulator. METHODS: The cross-sectional study was performed with 52 glaucoma patients and 15 control subjects. A series of hazard scenarios were presented, such as pedestrians crossing the street unexpectedly or vehicles suddenly pulling into the driver's lane. RTs in seconds (s) from first the evidence of a hazard to the time it took the driver to take the foot off the gas pedal ("Gas Off") and the time it took to depress the brake pedal ("Brake On") were compared between groups. RESULTS: Overall, mean RTs were statistically significantly slower in glaucoma patients (3.39±3.88 s) compared with controls (2.39±1.99 s; P =0.005) for the "Brake On" task but not for the "Gas Off" task (2.74±3.42 vs. 2.13±1.91 s, respectively; P =0.120). For subjects with glaucoma, multivariable models adjusted for age, gender, race, and visual acuity demonstrated significantly slower RTs for worse values of binocular mean sensitivity for both "Gas Off" and "Brake On" tasks (1.12 and 1.14 s slower per 10 dB worse; P =0.009 and P <0.001, respectively). Subjects with glaucoma took significantly longer times to brake for smaller (low saliency) hazards compared with larger (high saliency) hazards ( P =0.027). CONCLUSIONS: RTs in response to hazardous driving situations were slower for glaucoma patients compared with controls. Individualized assessment of driving fitness using hazardous scenarios in driving simulators could be helpful in providing an assessment of driving risk in glaucoma patients.

Gonioscopy-Assisted Transluminal Trabeculotomy for Glaucoma: 1-Year Outcomes and Success Predictors.

PRCIS: Our results suggest gonioscopy-assisted transluminal trabeculotomy (GATT) as an effective and safe option for the surgical management of open-angle glaucoma (OAG). Older age was the only risk factor for failure in our analysis. PURPOSE: To report 12-month clinical outcomes, safety profile and success predictors of GATT in patients with OAG. PATIENTS AND METHODS: A retrospective study of patients (18 y old and above) with medically uncontrolled OAG who underwent GATT as a solo procedure or combined with phacoemulsification (PHACO-GATT) between January 2018 and January 2020. Success at 12 months (primary outcome) was defined as intraocular pressure (IOP) <15 mm Hg, with an IOP reduction of at least 20%, OR a reduction of at least 2 glaucoma medications, compared with baseline. Secondary outcomes were success predictors and safety parameters. RESULTS: A total of 73 eyes (GATT=38; PHACO-GATT=35) from 58 patients with a mean age of 54.8±11.6 years were included. Overall, after 12 months of follow-up, the mean IOP was reduced from 24.9±8.5 to 12.1±2.1 mm Hg (P<0.001). The mean number of glaucoma medications was reduced from 3.5±0.7 to 1.2±1.2 (P<0.001). The success rate was 87% at 12 months, with no significant differences between GATT (85%) and PHACO-GATT (91%) eyes (P=0.330). Age was the only factor significantly associated with surgical success (hazard ratio=1.35; P=0.012; after adjusting for preoperative IOP and number of glaucoma medications). Patients older than 60 years had a significant greater chance of failure (hazard ratio=10.96; P=0.026) compared with those younger than 60 years. The most common postoperative complication was transient hyphema (39%; median duration, 5 d). No sight-threatening adverse event was documented. CONCLUSIONS: GATT was effective and safe at lowering IOP with or without cataract extraction in OAG. Patients 60 years or older had a higher risk of failure compared with those younger in age.

Gonioscopy-assisted transluminal trabeculotomy (GATT) outcomes in eyes with open-angle glaucoma resistant to maximum treatment / Resultados da técnica de trabeculotomia transluminal assistida por gonioscopia em olhos com glaucoma de ângulo aberto resistentes ao tratamento máximo

ABSTRACT Purpose: To report the initial 2 years' learning curve on gonioscopy-assisted transluminal trabeculotomy performed using the thermally blunted suture technique and review the factors that could potentially affect the outcome. Methods: This retrospective study evaluated 100 eyes from 89 participants with glaucoma resistant to maximum clinical treatment, which was defined as having an intraocular pressure >21 mmHg in addition to three or four different hypotensive drugs. Intraocular pressure values at baseline, 1 week, and at 1, 2, 3, 6, 12, and 24 months of follow-up and details regarding the need of antiglaucoma medication and further glaucoma surgery were recorded. Eyes that required further surgical intervention for intraocular pressure control were considered as failure. Results: A total of 51 eyes were subjected to isolated gonioscopy-assisted transluminal trabeculotomy, and 49 eyes were subjected to gonioscopy-assisted transluminal trabeculotomy + cataract extraction at the same surgical time. A statistically significant difference was observed between overall mean follow-up intraocular pressure and mean preoperative intraocular pressure (p<0.001) in all follow-up visits. When the extent of treatment was evaluated, patients with an extension of 360° did not exhibit statistically significantly lower mean intraocular pressure than those with other extensions. Hyphema was the only complication presented in 50 eyes (50%), but all had spontaneous resolution within 4 weeks. A total of 26 eyes (26%) required additional conventional trabeculectomy due to uncontrolled intraocular pressure, especially those who previously underwent vitreoretinal surgery. Conclusions: Gonioscopy-assisted transluminal trabeculotomy, besides being an apparently safe procedure, results in satisfactory success rates even during the surgeon's initial learning curve. The technique was effective in decreasing intraocular pressure and medication burden.

RESUMO Objetivo: Reportar a curva de aprendizado dos 2 anos iniciais da trabeculotomia transluminal assistida por gonioscopia, usando a técnica de sutura termicamente atenuada e revisar os fatores que podem afetar o resultado. Métodos: Este estudo retrospectivo incluiu 100 olhos de 89 participantes com glaucoma resistente ao tratamento clínico máximo, definido como tendo pressão intraocular superior a 21mmHg, além de três ou quatro drogas hipotensoras diferentes. Pressão intraocular inicial, 1 semana, primeiro, segundo, terceiro, sexto, 12 e 24 meses de acompanhamento; necessidade de medicação antiglaucoma; necessidade de mais cirurgias anti-glaucomatosas foram registradas. Olhos que necessitaram de intervenção cirúrgica adicional para o controle da pressão intraocular foram considerados como insucesso. Resultados: Cinquenta e um olhos foram submetidos à trabeculotomia transluminal assistida por gonioscopia isolado e 49 olhos à trabeculotomia transluminal assistida por gonioscopia associado à extração de catarata no mesmo tempo cirúrgico. Houve diferença estatisticamente significativa entre a pressão intraocular média global no acompanhamento e a pressão intraocular média pré-operatória (p<0,001) em todas as visitas do acompanhamento. Ao avaliar a extensão do tratamento, os pacientes com extensão de 360 graus não apresentaram pressão intraocular média menor estatisticamente significativa em comparação com outras extensões. O hifema foi a única complicação presente em 50 olhos (50%), contudo todos tiveram resolução espontânea em quatro semanas. Um total de 26 olhos (26%) teve que ser submetido a trabeculectomia convencional adicional devido à pressão intraocular descontrolada, principalmente aqueles previamente submetidos à cirurgia vitreorretiniana. Conclusões: A trabeculotomia transluminal assistida por gonioscopia, além de ser um procedimento aparentemente seguro, apresenta taxas de sucesso satisfatórias, mesmo durante a curva de aprendizado inicial do cirurgião. A técnica foi efetiva em reduzir a pressão intraocular e uso de medicamentos.

Gonioscopy-assisted transluminal trabeculotomy (GATT) outcomes in eyes with open-angle glaucoma resistant to maximum treatment.

PURPOSE: To report the initial 2 years' learning curve on gonioscopy-assisted transluminal trabeculotomy performed using the thermally blunted suture technique and review the factors that could potentially affect the outcome. METHODS: This retrospective study evaluated 100 eyes from 89 participants with glaucoma resistant to maximum clinical treatment, which was defined as having an intraocular pressure >21 mmHg in addition to three or four different hypotensive drugs. Intraocular pressure values at baseline, 1 week, and at 1, 2, 3, 6, 12, and 24 months of follow-up and details regarding the need of antiglaucoma medication and further glaucoma surgery were recorded. Eyes that required further surgical intervention for intraocular pressure control were considered as failure. RESULTS: A total of 51 eyes were subjected to isolated gonioscopy-assisted transluminal trabeculotomy, and 49 eyes were subjected to gonioscopy-assisted transluminal trabeculotomy + cataract extraction at the same surgical time. A statistically significant difference was observed between overall mean follow-up intraocular pressure and mean preoperative intraocular pressure (p<0.001) in all follow-up visits. When the extent of treatment was evaluated, patients with an extension of 360° did not exhibit statistically significantly lower mean intraocular pressure than those with other extensions. Hyphema was the only complication presented in 50 eyes (50%), but all had spontaneous resolution within 4 weeks. A total of 26 eyes (26%) required additional conventional trabeculectomy due to uncontrolled intraocular pressure, especially those who previously underwent vitreoretinal surgery. CONCLUSIONS: Gonioscopy-assisted transluminal trabeculotomy, besides being an apparently safe procedure, results in satisfactory success rates even during the surgeon's initial learning curve. The technique was effective in decreasing intraocular pressure and medication burden.

Comparing the Rule of 5 to Trend-based Analysis for Detecting Glaucoma Progression on OCT.

PURPOSE: The rule of 5 is a simple rule for detecting retinal nerve fiber layer (RNFL) change on spectral-domain OCT (SD-OCT), in which a loss of 5 µm of global RNFL on a follow-up test is considered evidence of significant change when compared with the baseline. The rule is based on short-term test-retest variability of SD-OCT and is often used in clinical practice. The purpose of this study was to compare the rule of 5 with trend-based analysis of global RNFL thickness over time for detecting glaucomatous progression. DESIGN: Prospective cohort. PARTICIPANTS: A total of 300 eyes of 210 glaucoma subjects followed for an average of 5.4±1.5 years with a median of 11 (interquartile range, 7-14) visits. METHODS: Trend-based analysis was performed by ordinary least-squares (OLS) linear regression of global RNFL thickness over time. For estimation of specificity, false-positives were obtained by assessing for progression on series of randomly permutated follow-up visits for each eye, which removes any systematic trend over time. The specificity of trend-based analysis was matched to that of the rule of 5 to allow meaningful comparison of the "hit rate," or the proportion of glaucoma eyes categorized as progressing at each time point, using the original sequence of visits. MAIN OUTCOME MEASURES: Comparison between hit rates of trend-analysis versus rule of 5 at matched specificity. RESULTS: After 5 years, the simple rule of 5 identified 37.5% of eyes as progressing at a specificity of 81.1%. At the same specificity, the hit rate for trend-based analysis was significantly greater than that of the rule of 5 (62.9% vs. 37.5%; P < 0.001). If the rule of 5 was required to be repeatable on a consecutive test, specificity improved to 93.4%, but hit rate decreased to 21.0%. At this higher specificity, trend-based analysis still had a significantly greater hit rate than the rule of 5 (47.4% vs. 21.0%, respectively; P < 0.001). CONCLUSIONS: Trend-based analysis was superior to the simple rule of 5 for identifying progression in glaucoma eyes and should be preferred as a method for longitudinal assessment of global SD-OCT RNFL change over time.

Mobile Telephone Use and Reaction Time in Drivers With Glaucoma.

Importance: Combining mobile telephone use with driving is not unusual. However, distracted driving limits driving performance because of limited capacity for persons to divide attention. Objectives: To investigate the frequency of mobile telephone use while driving and to assess whether patients with glaucoma had a disproportionate decrease in driving performance while conversing on a mobile telephone compared with healthy participants. Design, Setting, and Participants: Cross-sectional study of surveys collected from 112 patients with glaucoma and 70 control participants investigating mobile telephone use while driving. A randomly selected subgroup of 37 patients with glaucoma and 28 controls drove in a driving simulator to investigate peripheral event detection performance during distracted driving at the Visual Performance Laboratory, Duke University, Durham, North Carolina. Data collection was performed from December 1, 2016, through April 30, 2017. Exposures: Participants answered a survey and submitted to a driving simulation test with and without mobile telephone use. Main Outcomes and Measures: Survey answers were collected, and distracted driving performance, assessed by reaction time to peripheral stimuli, was analyzed. Results: Of the 182 participants who answered the survey, the 112 participants with glaucoma included 56 women (50.0%) and had a mean (SD) age of 73.6 (9.6) years. The 70 controls included 49 women (70.0%) and had a mean (SD) age of 68.4 (10.9) years. When asked about mobile telephone use while driving, 30 patients with glaucoma (26.8%) admitted rarely using and 2 (1.8%) sometimes using it. In the control group, 20 participants (28.6%) admitted rarely using and 2 (2.9%) sometimes using the telephone while driving (P = .80). Reaction times to peripheral stimuli were significantly longer among patients with glaucoma compared with controls during mobile telephone use (median [interquartile range], 1.86 [1.42-2.29] seconds vs 1.14 [0.98-1.59] seconds; P = .02). Compared with driving performance while not using a mobile telephone, the mean (SD) increase of 0.85 (0.60) second in reaction time while conversing on the mobile telephone among patients with glaucoma was significantly greater than the mean (SD) increase of 0.68 (0.83) second for controls (P = .03). Conclusions and Relevance: This study's findings indicate that patients with glaucoma use mobile telephones while driving as frequently as healthy participants. However, the findings also suggest that patients with glaucoma may experience a greater decline than healthy participants in their ability to detect peripheral events while driving when also talking on a mobile telephone. Patients with glaucoma should be informed that they may have a higher driving risk that may be worsened by distractions, such as mobile telephone use.

Visual Crowding in Glaucoma.

Purpose: Crowding refers to the phenomenon in which objects that can be recognized when viewed in isolation are unrecognizable in clutter. Crowding sets a fundamental limit to the capabilities of the peripheral vision and is essential in explaining performance in a broad array of daily tasks. Due to the effects of glaucoma on peripheral vision, we hypothesized that neural loss in the disease would lead to stronger effects of visual crowding. Methods: Subjects were asked to discriminate the orientation of a target letter when presented with surrounding flankers. The critical spacing value (scritical), which was required for correct discrimination of letter orientation, was obtained for each quadrant of the visual field. scritical values were correlated with standard automated perimetry (SAP) mean sensitivity (MS) and optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness measurements. Results: The study involved 13 subjects with mild glaucomatous visual field loss and 13 healthy controls. Glaucomatous eyes had significantly greater (worse) scritical than controls (170.4 ± 27.1 vs. 145.8 ± 28.0 minimum of visual angle, respectively; P = 0.007). scritical measurements were significantly associated with RNFL thickness measurements (R2 = 26%; P < 0.001) but not with SAP MS (P = 0.947). Conclusions: In glaucoma patients, a pronounced visual crowding effect is observed, even in the presence of mild visual field loss on standard perimetry. scritical was associated with the amount of neural loss quantified by OCT. These results may have implications for understanding how glaucoma patients are affected in daily tasks where crowding effects may be significant.

Is vision-related quality of life impaired in patients with preperimetric glaucoma?

BACKGROUND/AIMS: To investigate whether subjects with preperimetric glaucoma exhibit decline in patient-reported vision-related quality of life (QoL) compared with healthy individuals. METHODS: This cross-sectional study included 45 patients with preperimetric glaucoma, 102 patients with perimetric glaucoma and 81 healthy controls. Perimetric glaucoma was defined by the presence of repeatable abnormal standard automated perimetry tests and corresponding optic nerve damage in at least one eye. Preperimetric glaucoma was defined based on the presence of retinal nerve fibre layer (RNFL) loss as detected by spectral-domain optical coherence tomography in the absence of visual field loss. Patient-reported QoL was measured by the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25). RESULTS: Patients with preperimetric glaucoma had significantly thinner average RNFL in the better eye compared with controls (79.9±9.2 µm vs 97.8±8.6 µm; p<0.001). There was no significant difference in Rasch-calibrated NEI VFQ-25 scores between the preperimetric and control groups (72.8±16.8 vs 73.7±20.2, respectively; p=0.964). The average NEI VFQ-25 score in the perimetric glaucoma group was 58.9±18.6 and was significantly different than the average score in the preperimetric glaucoma and healthy groups (p<0.001 for both comparisons). CONCLUSION: Contrary to patients with perimetric damage, preperimetric glaucoma does not seem to be associated with loss in QoL. Prevention of disability from glaucoma may benefit from early diagnosis during a 'window of opportunity' given by detecting structural loss before visual field damage.

What Is the Amount of Visual Field Loss Associated With Disability in Glaucoma?

PURPOSE: To propose a new methodology for classifying patient-reported outcomes in glaucoma and for quantifying the amount of visual field damage associated with disability in the disease. DESIGN: Cross-sectional study. METHODS: A total of 263 patients with glaucoma were included. Vision-related disability was assessed by the National Eye Institute Visual Function Questionnaire (NEI VFQ-25). A latent class analysis (LCA) model was applied to analyze NEI VFQ-25 data and patients were divided into mutually exclusive classes according to their responses to the questionnaires. Differences in standard automated perimetry (SAP) mean deviation (MD) and integrated binocular mean sensitivity (MS) values between classes were investigated. The optimal number of classes was defined based on goodness-of-fit criteria, interpretability, and clinical utility. RESULTS: The model with 2 classes, disabled and nondisabled, had the best fit with an entropy of 0.965, indicating excellent separation of classes. The disabled group had 48 (18%) patients, whereas 215 (82%) patients were classified as nondisabled. The average MD of the better eye in the disabled group was -5.98 dB vs -2.51 dB in the nondisabled group (P < .001). For the worse eye, corresponding values were -13.36 dB and -6.05 dB, respectively (P < .001). CONCLUSION: Application of an LCA model allowed categorization of patient-reported outcomes and quantification of visual field levels associated with disability in glaucoma. A damage of approximately -6 dB for SAP MD, indicating relatively early visual field loss, may already be associated with significant disability if occurring in the better eye.

Association between Rates of Visual Field Progression and Intraocular Pressure Measurements Obtained by Different Tonometers.

PURPOSE: To investigate the associations between intraocular pressure (IOP) measurements obtained by different tonometric methods and rates of visual field loss in a cohort of patients with glaucoma followed over time. DESIGN: Prospective, observational cohort study. PARTICIPANTS: This study included 213 eyes of 125 glaucomatous patients who were followed for an average of 2.4±0.6 years. METHODS: At each visit, IOP measurements were obtained using Goldmann applanation tonometry (GAT), the Ocular Response Analyzer (ORA) (Reichert, Inc., Depew, NY), corneal-compensated IOP (IOPcc), and the ICare Rebound Tonometer (RBT) (Tiolat, Oy, Helsinki, Finland). Rates of visual field loss were assessed by standard automated perimetry (SAP) mean deviation (MD). Linear mixed models were used to investigate the relationship between mean IOP by each tonometer and rates of visual field loss over time, while adjusting for age, race, central corneal thickness, and corneal hysteresis. MAIN OUTCOME MEASURES: Strength of associations (R2) between IOP measurements from each tonometer and rates of SAP MD change over time. RESULTS: Average values for mean IOP over time measured by GAT, ORA, and RBT were 14.4±3.3, 15.2±4.2, and 13.4±4.2 mmHg, respectively. Mean IOPcc had the strongest relationship with SAP MD loss over time (R2 = 24.5%) and was significantly different from the models using mean GAT IOP (R2 = 11.1%; 95% confidence interval [CI] of the difference, 6.6-19.6) and mean RBT IOP (R2= 5.8%; 95% CI of the difference, 11.1-25.0). CONCLUSIONS: Mean ORA IOPcc was more predictive of rates of visual field loss than mean IOP obtained by GAT or RBT. By correcting for corneal-induced artifacts, IOPcc measurements may present significant advantages for predicting clinically relevant outcomes in patients with glaucoma.

Macular Pigment and Visual Function in Patients With Glaucoma: The San Diego Macular Pigment Study.

Purpose: Although recent studies have shown that macular pigment (MP) is significantly lower in glaucoma patients, this relationship merits further investigation. Methods: This cross-sectional study included 85 glaucoma patients and 22 controls. All subjects had standard automated perimetry (SAP) and retinal nerve fiber layer (RNFL) thickness measurements. Intake of lutein (L) and zeaxanthin (Z) was estimated using a novel dietary screener. The Heidelberg Spectralis dual-wavelength autofluorescence (AF) technology was employed to study the relationship between MP and glaucoma. The association between MP volume and glaucoma was investigated using linear regression models accounting for potential confounding factors. Results: Glaucoma patients had significantly worse SAP mean deviation (MD) and lower RNFL thickness in the study eye compared to control subjects (P < 0.001 for both). MP (volume) was comparable between groups (P = 0.436). In the univariable model, diagnosis of glaucoma was not associated with MP volume (R2 = 1.22%; P = 0.257). Dietary intake of L and Z was positively and significantly related to MP in the univariable (P = 0.022) and multivariable (P = 0.020) models. Conclusions: These results challenge previous studies that reported that glaucoma is associated with low MP. Dietary habits were found to be the main predictor of MP in this sample. Further research is merited to better understand the relationship between glaucoma, MP, and visual performance in these patients.

Event-based analysis of visual field change can miss fast glaucoma progression detected by a combined structure and function index.

PURPOSE: To investigate the relationship between progression assessed by the visual field guided progression analysis (GPA) and rates of structural and functional change in glaucoma eyes. METHODS: This was a longitudinal observational study of 135 eyes of 97 patients with glaucoma followed for an average of 3.5 ± 0.9 years. All patients had standard automated perimetry (SAP) and retinal nerve fiber layer (RNFL) analysis with spectral domain optical coherence tomography (SDOCT), with an average of 6.8 ± 2.3 visits. A control group of healthy eyes followed longitudinally was used to estimate age-related change. Visual field progression was assessed using the Humphrey Field Analyzer GPA. Estimates of retinal ganglion cell counts from SAP and SDOCT were used to obtain a combined index of glaucomatous damage (RGC index) according to a previously described algorithm. Progression by SDOCT and the retinal ganglion cell (RGC) index were defined as statistically significant (P < 0.05) slopes of change that were also faster than age-related change estimated from healthy eyes. RESULTS: From the 135 eyes, 15 (11%) progressed by GPA, 21 (16%) progressed by SDOCT, and 31 (23%) progressed by the RGC index. Twenty-one eyes showed progression by the RGC index that was missed by the GPA. These eyes had an average rate of change in estimated RGC counts of - 28,910 cells/year, ranging from two to nine times faster than expected age-related losses. CONCLUSION: Many glaucomatous eyes that are not found to be progressing by GPA may actually have fast rates of change as detected by a combined index of structure and function.

Optical Coherence Tomography Angiography Macular Vascular Density Measurements and the Central 10-2 Visual Field in Glaucoma.

PURPOSE: To evaluate the association between macula vascular density assessed by optical coherence tomography angiography (OCT-A) and central visual field (VF) threshold sensitivities in healthy, glaucoma suspect, and glaucoma patients. METHODS: A total of 185 eyes from 38 healthy participants, 31 glaucoma suspects, 72 mild glaucoma patients, and 44 moderate/severe glaucoma patients from the Diagnostic Innovations in Glaucoma Study who underwent OCT-A images of the macula and 10-2 VF testing were enrolled in this observational cross-sectional study. The relationship between central VF mean sensitivity (MS) and superficial macula whole-image vessel density (wiVD), and the relationship between the MS of the 4 central points of the 10-2 VF (MS4) and parafoveal vessel density (pfVD), were assessed using linear regression models. RESULTS: Mean wiVD (52.5%, 49.8%, 49.4% and 45.2%, respectively) and mean pfVD (54.9%, 52.1%, 51.8% and 47.7%, respectively) were found to be significantly higher in healthy eyes and glaucoma suspect eyes compared with glaucoma eyes with mild and moderate/severe disease [analysis of covariance (ANCOVA) P<0.001]. The univariate associations between 10-2 MS and wiVD (R=26.9%) and between 10-2 MS4 and pfVD (R=16.8%) were statistically significant (P<0.001 for both). After adjusting for scan quality, age, sex and intraocular pressure, superficial macula wiVD and pfVD were still independently associated with central VF loss. Macula wiVD performed better [area under the receiver operator characteristic (AUROC)=0.70] than ganglion cell complex thickness (AUROC=0.50) for differentiating between glaucoma suspect and healthy eyes (P=0.010). CONCLUSIONS: Loss of OCT-A macula vessel density is associated with central 10-2 VF defects. Macula vessel density is a clinically relevant parameter that may enhance monitoring of glaucoma suspects and patients.

The Association Between Macula and ONH Optical Coherence Tomography Angiography (OCT-A) Vessel Densities in Glaucoma, Glaucoma Suspect, and Healthy Eyes.

PURPOSE: To evaluate strength of associations between optical coherence tomography (OCT)-angiography vessel density (VD) measurements in the macula and peripapillary region of the optic nerve head (ONH) with standard structural OCT thickness measures. MATERIALS AND METHODS: This cross-sectional study included 333 eyes of 219 primary open-angle glaucoma patients, 41 glaucoma suspects, and 73 healthy participants from the Diagnostic Innovations in Glaucoma Study (DIGS) with good quality OCT angiography images. The strength of associations between microvasculature measures in the ONH retinal nerve fiber layer (RNFL) and superficial macula layer was assessed using linear regression models. Associations between ONH and macula VD, and circumpapillary (cp) RNFL thickness and macular ganglion cell complex (mGCC) measures were also evaluated. RESULTS: The strength (r) of associations among VD and thickness measures of ONH and macula ranged from 14.1% to 69.4%; all were statistically significant (P<0.001). The association between ONH and macula whole-image VD (r=41.0%) was significantly weaker than the relationship between mGCC and cpRNFL thickness (r=69.4%, P<0.001). Although both cpRNFL and mGCC thicknesses tended to be more strongly associated with ONH VD (r=39.2% and 26.7%, respectively) than macula VD (r=27.5% and 17.7%, respectively), differences did not reach statistical significance (P=0.050 and P=0.113, respectively). CONCLUSIONS: The strength of the association of VD with cpRNFL and mGCC thicknesses varies by retinal layer. The weaker association of macula VD compared with ONH VD with tissue thickness may be due to differences in micorovasculature between the macula and ONH.

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.

Fear of falling and postural reactivity in patients with glaucoma.

PURPOSE: To investigate the relationship between postural metrics obtained by dynamic visual stimulation in a virtual reality environment and the presence of fear of falling in glaucoma patients. METHODS: This cross-sectional study included 35 glaucoma patients and 26 controls that underwent evaluation of postural balance by a force platform during presentation of static and dynamic visual stimuli with head-mounted goggles (Oculus Rift). In dynamic condition, a peripheral translational stimulus was used to induce vection and assess postural reactivity. Standard deviations of torque moments (SDTM) were calculated as indicative of postural stability. Fear of falling was assessed by a standardized questionnaire. The relationship between a summary score of fear of falling and postural metrics was investigated using linear regression models, adjusting for potentially confounding factors. RESULTS: Subjects with glaucoma reported greater fear of falling compared to controls (-0.21 vs. 0.27; P = 0.039). In glaucoma patients, postural metrics during dynamic visual stimulus were more associated with fear of falling (R2 = 18.8%; P = 0.001) than static (R2 = 3.0%; P = 0.005) and dark field (R2 = 5.7%; P = 0.007) conditions. In the univariable model, fear of falling was not significantly associated with binocular standard perimetry mean sensitivity (P = 0.855). In the multivariable model, each 1 Nm larger SDTM in anteroposterior direction during dynamic stimulus was associated with a worsening of 0.42 units in the fear of falling questionnaire score (P = 0.001). CONCLUSION: In glaucoma patients, postural reactivity to a dynamic visual stimulus using a virtual reality environment was more strongly associated with fear of falling than visual field testing and traditional balance assessment.

Wayfinding and Glaucoma: A Virtual Reality Experiment.

Purpose: Wayfinding, the process of determining and following a route between an origin and a destination, is an integral part of everyday tasks. The purpose of this study was to investigate the impact of glaucomatous visual field loss on wayfinding behavior using an immersive virtual reality (VR) environment. Methods: This cross-sectional study included 31 glaucomatous patients and 20 healthy subjects without evidence of overall cognitive impairment. Wayfinding experiments were modeled after the Morris water maze navigation task and conducted in an immersive VR environment. Two rooms were built varying only in the complexity of the visual scene in order to promote allocentric-based (room A, with multiple visual cues) versus egocentric-based (room B, with single visual cue) spatial representations of the environment. Wayfinding tasks in each room consisted of revisiting previously visible targets that subsequently became invisible. Results: For room A, glaucoma patients spent on average 35.0 seconds to perform the wayfinding task, whereas healthy subjects spent an average of 24.4 seconds (P = 0.001). For room B, no statistically significant difference was seen on average time to complete the task (26.2 seconds versus 23.4 seconds, respectively; P = 0.514). For room A, each 1-dB worse binocular mean sensitivity was associated with 3.4% (P = 0.001) increase in time to complete the task. Conclusions: Glaucoma patients performed significantly worse on allocentric-based wayfinding tasks conducted in a VR environment, suggesting visual field loss may affect the construction of spatial cognitive maps relevant to successful wayfinding. VR environments may represent a useful approach for assessing functional vision endpoints for clinical trials of emerging therapies in ophthalmology.