Repeatability of visual function measures in age-related macular degeneration

INTERSESSION REPEATABILITY OF READING PERFORMANCE MEASURES IN PATIENTS WITH NEOVASCULAR AGE-RELATED MACULAR DEGENERATION

PURPOSE

To assess the intersession repeatability of reading performance measures in patients with previously treated neovascular age-related macular degeneration and good best-corrected visual acuity (≥20/40 Snellen).

METHODS

Ninety-one patients (91 eyes) with a diagnosis of previously treated neovascular age-related macular degeneration and good best-corrected visual acuity (≥20/40 Snellen) were prospectively enrolled. Reading performance metrics were assessed using Radner charts, and these measurements were repeated after 7 days to obtain the intersession repeatability. To test repeatability, we calculated the intraclass correlation coefficient, the 95% coefficient of repeatability, and the coefficient of variation for each reading parameter: 1) reading acuity (RA-LogRAD); 2) maximal reading speed-words per minute; 3) RA score (RA score-LogRAD); and 4) critical print size-LogRAD.

RESULTS

Mean ± standard deviation best-corrected visual acuity was 0.13 ± 0.01 logMAR [range: 0.00-0.30 logMAR]. The intraclass correlation coefficient values indicated a good reliability for all the analyzed metrics (0.901 for RA; 0.859 for max reading speed; 0.906 for RA score; and 0.868 for critical print size). The coefficient of repeatability was 0.2 LogRAD for RA, 63.2 words per minute for max reading speed, 0.2 LogRAD for RA score, and 0.2 LogRAD for critical print size. Coefficient of variation was 5.5% for RA, 8.9% for max reading speed, 5.8% for RA score, and 6.9% for critical print size.

CONCLUSION

Reading performance metrics are characterized by good values of intersession repeatability in patients with neovascular age-related macular degeneration with good best-corrected visual acuity. Our findings may grant the employment of such measures in trials assessing the visual outcome in these patients.

Relationship of Topographic Distribution of Macular Atrophy Secondary to Neovascular AMD and Reading Performance

Purpose

The purpose of this study was to provide a topographical assessment of macular atrophy in successfully treated neovascular age-related macular degeneration (AMD) eyes to investigate determinants of monocular reading performance.

Methods

A total of 60 participants (60 eyes) with previously treated neovascular AMD and absence of optical coherence tomography (OCT) signs of exudation were enrolled. Reading performance was assessed monocularly using Radner charts. The following variables were obtained: (i) the reading acuity was defined as the logarithm of the reading acuity determination (LogRAD), at the smallest sentence, a patient is able to read in less than 30 seconds; (ii) the maximum reading speed was defined as the fastest time achieved and is calculated in words per minute (wpm). OCT images were reviewed for the presence of macular atrophy within the central, 4 inner and 4 outer Early Treatment Diabetic Retinopathy Study (ETDRS) grid subfields. Contributory factors affecting reading performance were examined using univariable and multivariable linear mixed model considering reading acuity and reading speed as dependent variables.

Results

Median (interquartile range [IQR]) values were 0.53 (IQR = 0.17) LogRAD for reading acuity, and 144 (60) wpm for maximum reading speed. Thirty-five out of 60 (58.3%) eyes were characterized by the presence of macular atrophy. In multiple regression analysis, reading acuity was significantly associated with presence of macular atrophy in the foveal central circle (P = 0.024). Conversely, the maximum reading speed was associated with presence of macular atrophy in the inner-right ETDRS subfield (P = 0.005).

Conclusions

We showed a significant relationship between presence and location of macular atrophy and reading performance in neovascular AMD.

Towards a population pharmacokinetic/pharmacodynamic model of anti-VEGF therapy in patients with age-related macular degeneration

PURPOSE

To develop a population pharmacokinetic/pharmacodynamic model (popPKPD) of intravitreal bevacizumab treatment for neovascular age-related macular degeneration (nAMD) patients to learn about the PK/PD relationship and utilise it for dosing regimen decisions on future nAMD patients.

METHODS

The Greater Manchester Avastin for Neovascularisation (GMAN) randomised clinical trial data was retrospectively utilised, and the best-corrected visual acuity (BCVA) and central macular retinal thickness (CRT, measured by optical coherence tomography) were the PD inputs to the model. Using the nonlinear mixed-effects method, the best PKPD structural model was investigated, and the clinical significance of the two different dosing treatment regimens (as-needed versus routine) was evaluated.

RESULTS

A structural model to describe the change of BCVA from the baseline of nAMD patients was successfully obtained based on the turnover PD model concept (drug stimulates the "visual acuity response production"). The popPKPD model and simulation indicate that the routine regimen protocol improves patient visual outcome compared to the as-needed protocol. For the change in CRT, the turnover structural PKPD model was too demanding to fit to the given clinical data.

CONCLUSIONS

This is the first popPKPD attempt in nAMD treatment that shows the potential of this strategy to understand/inform the dosing regimen. Clinical trials with richer PD data will provide the means to build more robust models.

Repeatability and Discriminatory Power of Chart-Based Visual Function Tests in Individuals With Age-Related Macular Degeneration: A MACUSTAR Study Report

Question

Under multicenter, multiexaminer conditions, do simple chart-based assessments of visual function (VF) have sufficient repeatability and discrimination in people with age-related macular degeneration (AMD) to be considered as measures for future clinical trial end points?

Findings

In this cross-sectional study including 245 people with AMD and 56 healthy, age-similar control individuals, best-corrected visual acuity, low-luminance visual acuity, Moorfields Acuity Test, contrast sensitivity, and International Reading Speed Test had adequate repeatability but limited power to discriminate between no AMD and intermediate AMD (iAMD).

Meaning

The findings suggest that the chart-based tests included in this study perform sufficiently well to be considered as potential measures for clinical trial end points; their prognostic power to predict conversion from iAMD to late AMD needs to be examined with longitudinal data.

Importance

There is a need for validated clinical end points that are reliably able to quantify potential therapeutic effects of future treatments targeting age-related macular degeneration (AMD) before the onset of serious visual impairment.

Objective

To assess the reliability and discriminatory power of 5 simple chart-based visual function (VF) tests as potential measures for clinical trial end points with regulatory and patient-access intention in intermediate AMD (iAMD).

Design, Setting, and Participants

This international noninterventional study took place at 18 tertiary ophthalmology departments across Europe. Participants were recruited between April 2018 and March 2020 and were identified during routine clinical review. Participants with no AMD and early AMD were recruited from hospital staff, friends, and family of participants with AMD and via referrals from community ophthalmologists and optometrists. The repeatability and discriminatory power of 5 simple chart-based assessments of VF (best-corrected visual acuity [BCVA], low-luminance visual acuity [LLVA], Moorfields Acuity Test [MAT], Pelli-Robson Contrast Sensitivity [CS], and International Reading Speed Test [IReST]) were assessed in a repeated-measures design. VF assessments were performed on day 0 and day 14. Participants with early AMD, iAMD, late AMD, and no AMD were recruited.

Main Outcomes and Measures

Intraclass correlation coefficients (ICCs) and Bland-Altman 95% limits of agreement (LoA) were computed to assess repeatability. Area under the receiver operating characteristic curves (AUCs) determined the discriminatory ability of all measures to classify individuals as having no AMD or iAMD and to differentiate iAMD from its neighboring disease states.

Results

A total of 301 participants (mean [SD] age, 71 [7] years; 187 female participants [62.1%]) were included in the study. Thirty-four participants (11.3%) had early AMD, 168 (55.8%) had iAMD, 43 (14.3%) had late AMD, and 56 (18.6%) had no AMD. ICCs for all VF measures ranged between 0.88 and 0.96 when all participants were considered, indicating good to excellent repeatability. All measures displayed excellent discrimination between iAMD and late AMD (AUC, 0.92-0.99). Early AMD was indistinguishable from iAMD on all measures (AUC, 0.54-0.64). CS afforded the best discrimination between no AMD and iAMD (AUC, 0.77). Under the same conditions, BCVA, LLVA, and MAT were fair discriminators (AUC, 0.69-0.71), and IReST had poor discrimination (AUC, 0.57-0.61).

Conclusions and Relevance

BCVA, LLVA, MAT, CS, and IReST had adequate repeatability in this multicenter, multiexaminer setting but limited power to discriminate between no AMD and iAMD. The prognostic power of these variables to predict conversion from iAMD to late AMD is being examined in the ongoing longitudinal part of the MACUSTAR study.

Contrast Sensitivity in Early to Intermediate Age-Related Macular Degeneration (AMD)

PURPOSE

Previous studies indicated that advanced age-related macular degeneration (AMD) affects contrast sensitivity (CS) in humans. The CS results for early/intermediate AMD patients are contradictory. The purpose of this study was to determine if CS testing discriminates early/intermediate AMD patients with normal acuity from normal patients.

METHODS

Forty-nine subjects (25 control and 24 early/intermediate AMD patients) were chosen for this project. The age (p = .16) and acuity (p = .34) was not significantly different between the groups. The average simplified AREDS AMD grade for the AMD patients was 2.75 ± 1.03. Three CS functions employing a descending method of limits were measured at the fovea (1. stationary stimulus and, 2. 16 Hz counter-phase stimulus under photopic conditions and 3. the stationary stimulus viewed through a 2 log unit neutral density filter (mesopic condition, background luminance of 1 cd/m²)) and at 4 deg right or left of the fovea with a horizontally oriented sine wave grating (5 deg diameter) viewed on a VPixx monitor (luminance of 100 cd/m²).

RESULTS

The early AMD patients were no different from the control patients for any test condition. The intermediate AMD patients were significantly different from the control patients for the mesopic CS function (p = .05). Post-hoc 2-sample t-tests for the intermediate AMD patients were significantly different from the control patients under the stationary photopic and mesopic conditions for the 1.5 cycle per degree stimulus.

CONCLUSIONS

Group differences in CS were only found in intermediate AMD patients. The loss in CS increased for the intermediate AMD patients under low light levels. Thus, CS may not be the optimal test to discriminate early AMD from control patients so other tests measured under dark adapted conditions should be investigated.

Switching to Brolucizumab in Neovascular Age-Related Macular Degeneration Incompletely Responsive to Ranibizumab or Aflibercept: Real-Life 6 Month Outcomes

Purpose: The aim of this study was to evaluate the effect of switching treatment in eyes with neovascular age-related macular degeneration (nAMD) and treatment intervals of ≤6 weeks to brolucizumab. Methods: In this prospective series, eyes with persisting retinal fluid under aflibercept or ranibizumab every 4–6 weeks were switched to brolucizumab. Visual acuity (BCVA), reading acuity (RA), treatment intervals, central subfield thickness (CST), and the presence of intra- and subretinal fluid were recorded over 6 months. Results: Seven of 12 eyes completed the 6 month follow-up and received 4.4 ± 0.5 brolucizumab injections within 28.0 ± 2.8 weeks. Treatment intervals increased from 5.3 ± 0.9 weeks to 9.0 ± 2.8 weeks (95% confidence interval of extension (CI): 1.6 to 5.9). BCVA improved from 67.8 ± 7.2 to 72.2 ± 7.5 (95% CI: −0.3 to 9.1) ETDRS letters, RA improved from 0.48 ± 0.15 to 0.31 ± 0.17 LogRAD (95% CI: 0.03 to 0.25), and CST improved from 422.1 ± 97.3 to 353.6 ± 100.9 µm (95% CI: −19.9 to 157.1). Treatment was terminated early in five eyes (two intraocular inflammations with vascular occlusion without vision loss, one stroke, and two changes in the treatment plan). Conclusions: Improvement in visual performance and longer treatment intervals in our series over 6 months indicate the potential of brolucizumab to reduce the treatment burden in nAMD, while two instances of intraocular inflammation were encountered.

Test-Retest-Reliability of Computer-Based Metamorphopsia Measurement in Macular Diseases

In this study, the test-retest-reliability as one aspect of reliability of metamorphopsia measurements using a computer-based measuring method was determined in patients with macular diseases. Metamorphopsia amplitude, position, and area were quantified using AMD - A Metamorphopsia Detector software (app4eyes GmbH & Co. KG, Germany) in patients with diabetic, myopic, or uveitic macular edema, intermediate or neovascular age-associated macular degeneration, epiretinal membrane, vitelliform maculopathy, Irvine-Gass syndrome, or macular edema due to venous retinal occlusion. The intraclass correlation coefficient (ICC) was calculated in order to determine the repeatability of two repeated measurements and was used as an indicator of the reliability of the measurements. In this study, metamorphopsia measurements were conducted on 36 eyes with macular diseases. Metamorphopsia measurements made using AMD - A Metamorphopsia Detector software were highly reliable and repeatable in patients with maculopathies. The intraclass correlation coefficient of all indices was excellent (0.95 - 0.97). For diseases of the vitreoretinal interface or macular diseases with intra- or subretinal edema, this metamorphopsia measurement represents a supplement for visual function testing in the clinic, as well as in clinical studies.

Use of a Neural Net to Model the Impact of Optical Coherence Tomography Abnormalities on Vision in Age-related Macular Degeneration

PURPOSE

To develop a neural network for the estimation of visual acuity from optical coherence tomography (OCT) images of patients with neovascular age-related macular degeneration (AMD) and to demonstrate its use to model the impact of specific controlled OCT changes on vision.

DESIGN

Artificial intelligence (neural network) study.

METHODS

We assessed 1400 OCT scans of patients with neovascular AMD. Fifteen physical features for each eligible OCT, as well as patient age, were used as input data and corresponding recorded visual acuity as the target data to train, validate, and test a supervised neural network. We then applied this network to model the impact on acuity of defined OCT changes in subretinal fluid, subretinal hyperreflective material, and loss of external limiting membrane (ELM) integrity.

RESULTS

A total of 1210 eligible OCT scans were analyzed, resulting in 1210 data points, which were each 16-dimensional. A 10-layer feed-forward neural network with 1 hidden layer of 10 neurons was trained to predict acuity and demonstrated a root mean square error of 8.2 letters for predicted compared to actual visual acuity and a mean regression coefficient of 0.85. A virtual model using this network demonstrated the relationship of visual acuity to specific, programmed changes in OCT characteristics. When ELM is intact, there is a shallow decline in acuity with increasing subretinal fluid but a much steeper decline with equivalent increasing subretinal hyperreflective material. When ELM is not intact, all visual acuities are reduced. Increasing subretinal hyperreflective material or subretinal fluid in this circumstance reduces vision further still, but with a smaller gradient than when ELM is intact.

CONCLUSIONS

The supervised machine learning neural network developed is able to generate an estimated visual acuity value from OCT images in a population of patients with AMD. These findings should be of clinical and research interest in macular degeneration, for example in estimating visual prognosis or highlighting the importance of developing treatments targeting more visually destructive pathologies.

Development and testing of an automated computer tablet-based method for self-testing of high and low contrast near visual acuity in ophthalmic patients

PURPOSE

Many eye diseases require on-going assessment for optimal management, creating an ever-increasing burden on patients and hospitals that could potentially be reduced through home vision monitoring. However, there is limited evidence for the utility of current applications and devices for this. To address this, we present a new automated, computer tablet-based method for self-testing near visual acuity (VA) for both high and low contrast targets. We report on its reliability and agreement with gold standard measures.

METHODS

The Mobile Assessment of Vision by intERactIve Computer (MAVERIC) system consists of a calibrated computer tablet housed in a bespoke viewing chamber. Purpose-built software automatically elicits touch-screen responses from subjects to measure their near VA for either low or high contrast acuity. Near high contrast acuity was measured using both the MAVERIC system and a near Landolt C chart in one eye for 81 patients and low contrast acuity using the MAVERIC system and a 25 % contrast near EDTRS chart in one eye of a separate 95 patients. The MAVERIC near acuity was also retested after 20 min to evaluate repeatability.

RESULTS

Repeatability of both high and low contrast MAVERIC acuity measures, and their agreement with the chart tests, was assessed using the Bland-Altman comparison method. One hundred and seventy-three patients (96 %) completed the self- testing MAVERIC system without formal assistance. The resulting MAVERIC vision demonstrated good repeatability and good agreement with the gold-standard near chart measures.

CONCLUSIONS

This study demonstrates the potential utility of the MAVERIC system for patients with ophthalmic disease to self-test their high and low contrast VA. The technique has a high degree of reliability and agreement with gold standard chart based measurements.

High Tech Aids Low Vision: A Review of Image Processing for the Visually Impaired

Recent advances in digital image processing provide promising methods for maximizing the residual vision of the visually impaired. This paper seeks to introduce this field to the readership and describe its current state as found in the literature. A systematic search revealed 37 studies that measure the value of image processing techniques for subjects with low vision. The techniques used are categorized according to their effect and the principal findings are summarized. The majority of participants preferred enhanced images over the original for a wide range of enhancement types. Adapting the contrast and spatial frequency content often improved performance at object recognition and reading speed, as did techniques that attenuate the image background and a technique that induced jitter. A lack of consistency in preference and performance measures was found, as well as a lack of independent studies. Nevertheless, the promising results should encourage further research in order to allow their widespread use in low-vision aids.

Routine versus As-Needed Bevacizumab with 12-Weekly Assessment Intervals for Neovascular Age-Related Macular Degeneration: 92-Week Results of the GMAN Trial

PURPOSE

To evaluate the efficacy and safety of intravitreal bevacizumab (Avastin; Genentech, South San Francisco, CA) in patients with neovascular age-related macular degeneration (nAMD) using 2 different treatment regimens in which patients were assessed clinically at up to 12-week intervals.

DESIGN

Randomized, controlled, noninferiority trial.

PARTICIPANTS

A total of 331 patients with nAMD.

METHODS

Patients were treated with 1.25 mg intravitreal bevacizumab and followed up to 92 weeks. They were randomized into 2 arms. All patients received 3 loading doses 4 weeks apart and thereafter were assessed every 12 weeks until the end of the study. One arm received a routine treatment at each 12-week assessment, and the other arm was treated at these assessments on an as-needed basis. After the loading doses, patients in either arm who showed signs of disease activity had an additional assessment after 6 weeks and at that visit had top-up treatments on an as-needed basis.

MAIN OUTCOME MEASURES

Mean best-corrected visual acuity (BCVA) at 92 weeks.

RESULTS

At 92 weeks, patients who had treatments every 12 weeks had superior BCVA to those treated on an as-needed basis every 12 weeks (P = 0.008), with the regular treatment arm gaining a mean BCVA of 5.5 letters and the as-needed treatment arm gaining 0.6 letters. The regular treatment arm of the study showed significantly improved outcomes with respect to 5-, 10-, and 15-letter changes in BCVA from baseline compared with the as-needed treatment arm, as well as superior reading speed. In patients who completed the study, up to but not including week 92, the mean number of treatments was 10.8 for the regular treatment arm and 9.1 for the as-needed treatment arm.

CONCLUSIONS

A treatment regimen with regular bevacizumab injections every 12 weeks after loading doses supplemented with as-needed top-up treatments produced a stable improvement in BCVA from baseline. The improvement in BCVA was broadly similar to that obtained in other studies using anti-vascular endothelial growth factor drugs with more frequent assessments and treatments.