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To study the associations between optic nerve head (ONH) strains under intraocular pressure (IOP) elevation with retinal sensitivity in patients with glaucoma.Clinic-based cross-sectional study.Two hundred twenty-nine patients with primary open-angle glaucoma (subdivided into 115 patients with high-tension glaucoma [HTG] and 114 patients with normal-tension glaucoma [NTG]).For 1 eye of each patient, we imaged the ONH using spectral-domain OCT under the following conditions: (1) primary gaze and (2) primary gaze with acute IOP elevation (to approximately 35 mmHg) achieved through ophthalmodynamometry. A 3-dimensional strain-mapping algorithm was applied to quantify IOP-induced ONH tissue strain (i.e., deformation) in each ONH. Strains in the prelaminar tissue (PLT), the retina, the choroid, the sclera, and the lamina cribrosa (LC) were associated (using linear regression) with measures of retinal sensitivity from the 24-2 Humphrey visual field test (Carl Zeiss Meditec). This was performed globally, then locally according to a previously published regionalization scheme.Associations between ONH strains and values of retinal sensitivity from visual field testing.For patients with HTG, we found (1) significant negative linear associations between ONH strains and retinal sensitivity (P0.001; on average, a 1% increase in ONH strains corresponded to a decrease in retinal sensitivity of 1.1 decibels [dB]), (2) that high-strain regions colocalized with anatomically mapped regions of high visual field loss, and (3) that the strongest negative associations were observed in the superior region and in the PLT. In contrast, for patients with NTG, no significant associations between strains and retinal sensitivity were observed except in the superotemporal region of the LC.We found significant negative associations between IOP-induced ONH strains and retinal sensitivity in a relatively large glaucoma cohort. Specifically, patients with HTG who experienced higher ONH strains were more likely to exhibit lower retinal sensitivities. Interestingly, this trend in general was less pronounced in patients with NTG, which could suggest a distinct pathophysiologic relationship between the two glaucoma subtypes.

PURPOSE: To assess the psychometric properties of glaucoma-specific health-related quality of life (HRQoL) item banks (IBs), and explore their efficiency using computerized adaptive testing (CAT) simulations. METHODS: In this cross-sectional, clinical study, 300 Asian glaucoma patients answered 221 items within seven IBs: Ocular Comfort Symptoms (OS); Activity Limitation (AL); Lighting (LT); Mobility (MB); Glaucoma Management (GM); Psychosocial (PSY); and Work (WK). Rasch analysis was conducted to assess each IB's psychometric properties (e.g., item "fit" to the construct; unidimensionality) and a set of analytic performance criteria guiding decision making relating to retaining or dropping domains and items was employed. CAT simulations determined the mean number of items for 'high' and 'moderate' measurement precision (stopping rule: SEM 0.3 and 0.387, respectively). RESULTS: Participants' mean age was 67.2 ± 9.2 years (62% male; 87% Chinese). LT, MB, and GM displayed good psychometric properties overall. To optimize AL's psychometric properties, 16 items were deleted due to poor "fit", high missing data, item bias, low discrimination and/or a low clinical/patient importance rating. To resolve multidimensionality in PSY, we rehomed 16 items into a "Concern (CN)" domain. PSY and CN required further amendment, including collapsing of response categories, and removal of poorly functioning items (N = 7). Due to poor measurement precision, low applicability and high ceiling effect, low test information indices, and low item separation index the WK IB was not considered further. In CAT simulations on the final seven IBs (n = 182 items total), an average of 12.1 and 15.7 items per IB were required for moderate and high precision measurement, respectively. CONCLUSIONS: After reengineering our seven IBs, they displayed robust psychometric properties and good efficiency in CAT simulations. Once finalized, GlauCAT™-Asian may enable comprehensive assessment of the HRQoL impact of glaucoma and associated treatments.

Background To determine the agreement between intraocular pressure (IOP) measurements using conventional Goldmann applanation tonometry (GAT) and SUOER SW-500 Rebound Tonometer. Methods This was a prospective observational study where 205 eyes of 106 glaucoma patients had their IOPs measured by 2 fellowship trained ophthalmologists. Data were analysed using the Bland-Altman method of differences. Correlation was measured using the Pearson coefficient. Results Most of our patients were Chinese (88.7%) and female (51.9%). The average age was 66.9 years. The range of IOPs as measured by GAT was 2 to 58 mm Hg. Using the Bland-Altman method to compare GAT and SUOER SW-500 Rebound Tonometer. The tonometer overestimated the IOP by 0.5mm Hg in the right eye and underestimated it by 0.1 mm Hg in the left eye. The Tonometer IOP correlated well with GAT, with a Pearson coefficient of correlation(r) of 0.89 (P < 0.001) for the right eye and 0.86 (P < 0.001) for the left eye, respectively. In patients with GAT IOP ≥ 21 mm Hg (n = 25), the Tonometer underestimated the IOP by 2.96 mm Hg. Conclusions The IOP measurements from the SUOER SW-500 Rebound Tonometer correlates with the conventional GAT in measuring the IOP. SUOER SW-500 Rebound Tonometer may be of use, especially if the risk of transmission of infection is high considering that the probes are disposable. It is easy to use and its small size and portability makes it useful in situations where the patient is unable to be examined at the slit lamp.

Objectives To report the processes used to design and implement an assessment tool to inform funding decisions for competing health innovations in a tertiary hospital. Methods We designed an assessment tool for health innovation proposals with three components: “value to the institution,” “novelty,” and “potential for adoption and scaling.” The “value to the institution” component consisted of twelve weighted value attributes identified from the host institution’s annual report; weights were allocated based on a survey of the hospital’s leaders. The second and third components consisted of open-ended questions on “novelty” and “barriers to implementation” to support further dialogue. Purposive literature review was performed independently by two researchers for each assessment. The assessment tool was piloted during an institutional health innovation funding cycle. Results We used 17 days to evaluate ten proposals. The completed assessments were shared with an independent group of panellists, who selected five projects for funding. Proposals with the lowest scores for “value to the institution” had less perceived impact on the patient-related value attributes of “access,” “patient centeredness,” “health outcomes,” “prevention,” and “safety.” Similar innovations were reported in literature in seven proposals; potential barriers to implementation were identified in six proposals. We included a worked example to illustrate the assessment process. Conclusions We developed an assessment tool that is aligned with local institutional priorities. Our tool can augment the decision-making process when funding health innovation projects. The tool can be adapted by others facing similar challenges of trying to choose the best health innovations to fund.

PurposeTo assess intraocular pressure (IOP)-induced and gaze-induced optic nerve head (ONH) strains in subjects with high-tension glaucoma (HTG) and normal-tension glaucoma (NTG).DesignClinic-based cross-sectional study.MethodsThe ONH from one eye of 228 subjects (114 subjects with HTG (pre-treatment IOP≥21 mm Hg) and 114 with NTG (pre-treatment IOPResultsAcross all subjects, adduction generated high effective strain (4.4%±2.3%) in the LC tissue with no significant difference (p>0.05) with those induced by IOP elevation (4.5%±2.4%); while abduction generated significantly lower (p=0.01) effective strain (3.1%±1.9%). The lamina cribrosa (LC) of HTG subjects exhibited significantly higher effective strain than those of NTG subjects under IOP elevation (HTG: 4.6%±1.7% vs NTG: 4.1%±1.5%, pConclusionWe found that NTG subjects experienced higher strains due to adduction than HTG subjects, while HTG subjects experienced higher strain due to IOP elevation than NTG subjects—and that these differences were most pronounced in the LC tissue.

Background/aimsTo use artificial intelligence (AI) to: (1) exploit biomechanical knowledge of the optic nerve head (ONH) from a relatively large population; (2) assess ONH robustness (ie, sensitivity of the ONH to changes in intraocular pressure (IOP)) from a single optical coherence tomography (OCT) volume scan of the ONH without the need for biomechanical testing and (3) identify what critical three-dimensional (3D) structural features dictate ONH robustness.Methods316 subjects had their ONHs imaged with OCT before and after acute IOP elevation through ophthalmo-dynamometry. IOP-induced lamina cribrosa (LC) deformations were then mapped in 3D and used to classify ONHs. Those with an average effective LC strain superior to 4% were considered fragile, while those with a strain inferior to 4% robust. Learning from these data, we compared three AI algorithms to predict ONH robustness strictly from a baseline (undeformed) OCT volume: (1) a random forest classifier; (2) an autoencoder and (3) a dynamic graph convolutional neural network (DGCNN). The latter algorithm also allowed us to identify what critical 3D structural features make a given ONH robust.ResultsAll three methods were able to predict ONH robustness from a single OCT volume scan alone and without the need to perform biomechanical testing. The DGCNN (area under the curve (AUC): 0.76±0.08) outperformed the autoencoder (AUC: 0.72±0.09) and the random forest classifier (AUC: 0.69±0.05). Interestingly, to assess ONH robustness, the DGCNN mainly used information from the scleral canal and the LC insertion sites.ConclusionsWe propose an AI-driven approach that can assess the robustness of a given ONH solely from a single OCT volume scan of the ONH, and without the need to perform biomechanical testing. Longitudinal studies should establish whether ONH robustness could help us identify fast visual field loss progressors.PrecisUsing geometric deep learning, we can assess optic nerve head robustness (ie, sensitivity to a change in IOP) from a standard OCT scan that might help to identify fast visual field loss progressors.

PurposeTo study the associations between optic nerve head (ONH) strains under intraocular pressure (IOP) elevation with retinal sensitivity in glaucoma subjects.DesignClinic based cross-sectional study.Participants229 subjects with primary open angle glaucoma (subdivided into 115 high tension glaucoma (HTG) subjects and 114 normal tension glaucoma (NTG) subjects).MethodsFor one eye of each subject, we imaged the ONH using spectral-domain optical coherence tomography (OCT) under the following conditions: (1) primary gaze and (2) primary gaze with acute IOP elevation (to approximately 33 mmHg) achieved through ophthalmodynamometry. A 3-dimensional (3D) strain-mapping algorithm was applied to quantify IOP-induced ONH tissue strain (i.e. deformation) in each ONH. Strains in the pre-lamina tissue (PLT)and the retina, the choroid, the sclera and the lamina cribrosa (LC) were associated (using linear regression) with measures of retinal sensitivity from the 24-2 Humphrey visual field test (Carl Zeiss Meditec, Dublin, CA, USA). This was done globally, then locally according to the regionalization scheme of Garway-Heath et al.Main Outcome MeasuresAssociations between ONH strains and values of retinal sensitivity from visual field testing.ResultsFor HTG subjects, we found that (1) there were significant negative linear associations between ONH strains and retinal sensitivity (p(2) high strain regions co-localized with anatomically-mapped regions of high visual field loss, (3) the strongest negative associations were observed in the superior region and in the PLT. In contrast, for NTG subjects, no significant associations between strains and retinal sensitivity were observed except in the supero-temporal region of the LC.ConclusionWe found significant negative associations between IOP-induced ONH strains and retinal sensitivity in a relatively large glaucoma cohort. Specifically, HTG subjects who experienced higher ONH strains were more likely to exhibit lower retinal sensitivities. Interestingly, this trend was in general less pronounced in NTG subjects, which could suggest a distinct pathophysiology between the two glaucoma subtypes.

To assess whether the 3-dimensional (3D) structural configuration of the central retinal vessel trunk and its branches (CRVTB) could be used as a diagnostic marker for glaucoma.Retrospective, deep-learning approach diagnosis study.We trained a deep learning network to automatically segment the CRVTB from the B-scans of the optical coherence tomography (OCT) volume of the optic nerve head. Subsequently, 2 different approaches were used for glaucoma diagnosis using the structural configuration of the CRVTB as extracted from the OCT volumes. In the first approach, we aimed to provide a diagnosis using only 3D convolutional neural networks and the 3D structure of the CRVTB. For the second approach, we projected the 3D structure of the CRVTB orthographically onto sagittal, frontal, and transverse planes to obtain 3 two-dimensional (2D) images, and then a 2D convolutional neural network was used for diagnosis. The segmentation accuracy was evaluated using the Dice coefficient, whereas the diagnostic accuracy was assessed using the area under the receiver operating characteristic curves (AUCs). The diagnostic performance of the CRVTB was also compared with that of retinal nerve fiber layer (RNFL) thickness (calculated in the same cohorts).Our segmentation network was able to efficiently segment retinal blood vessels from OCT scans. On a test set, we achieved a Dice coefficient of 0.81 ± 0.07. The 3D and 2D diagnostic networks were able to differentiate glaucoma from nonglaucoma subjects with accuracies of 82.7% and 83.3%, respectively. The corresponding AUCs for the CRVTB were 0.89 and 0.90, higher than those obtained with RNFL thickness alone (AUCs ranging from 0.74 to 0.80).Our work demonstrated that the diagnostic power of the CRVTB is superior to that of a gold-standard glaucoma parameter, that is, RNFL thickness. Our work also suggested that the major retinal blood vessels form a "skeleton"-the configuration of which may be representative of major optic nerve head structural changes as typically observed with the development and progression of glaucoma.

There is limited literature on lifestyle and health factors related to primary open-angle glaucoma amongst Asians.This study evaluated the association of primary open-angle glaucoma with smoking, health and ocular factors amongst Chinese Singaporeans.Case-control study.The study used 711 primary open-angle glaucoma patients from a Singapore hospital and 2788 population-based controls.Subjects underwent clinical examination and completed a questionnaire with details on family history of glaucoma, comorbidities, smoking and alcohol consumption. Glaucoma cases were subclassified as normal or high-tension glaucoma according to their untreated intraocular pressures.The association of various health and lifestyle factors, with normal-tension and high-tension glaucoma was evaluated.Using multiple logistic regression, primary open-angle glaucoma was associated with older age (odds ratio 1.12 per year older; 95% confidence interval 1.10-1.15; P0.001), family history of glaucoma (odds ratio 7.86; 95% confidence interval 4.48-13.79; P0.001), higher intraocular pressure (odds ratio 1.75 per 1 mmHg; 95% confidence interval 1.64-1.87; P0.001) and thinner central corneal thickness (odds ratio 1.01; 95% confidence interval 1.01-1.02; P0.001). Myopes were more likely to have primary open-angle glaucoma (P0.001). A current smoking habit was protective against normal-tension glaucoma (odds ratio 0.30; 95% confidence interval 0.10-0.92; P = 0.035).Older age, family history of glaucoma, higher intraocular pressure, thinner central corneal thickness and myopia were significantly associated with primary open-angle glaucoma amongst Chinese Singaporeans.

Secondary glaucoma is a well-known complication post vitreoretinal surgery that is often difficult to manage. We report an unusual case of compressive angle crowding and fibrin induced pupillary block secondary to anterior segment ischemia following combined scleral buckle and vitrectomy surgery. Surgical removal of the fibrin membrane proved effective in reducing intraocular pressure and preventing glaucomatous damage to the optic disc.