Evaluation of an offline, artificial intelligence system for referable glaucoma screening using a smartphone-based fundus camera: a prospective study.

BACKGROUND/OBJECTIVES: An affordable and scalable screening model is critical for undetected glaucoma. The study evaluated the performance of an offline, smartphone-based AI system for the detection of referable glaucoma against two benchmarks: specialist diagnosis following full glaucoma workup and consensus image grading. SUBJECTS/METHODS: This prospective study (tertiary glaucoma centre, India) included 243 subjects with varying severity of glaucoma and control group without glaucoma. Disc-centred images were captured using a validated smartphone-based fundus camera analysed by the AI system and graded by specialists. Diagnostic ability of the AI in detecting referable Glaucoma (Confirmed glaucoma) and no referable Glaucoma (Suspects and No glaucoma) when compared to a final diagnosis (comprehensive glaucoma workup) and majority grading (image grading) by Glaucoma specialists (pre-defined criteria) were evaluated. RESULTS: The AI system demonstrated a sensitivity and specificity of 93.7% (95% CI: 87.6-96.9%) and 85.6% (95% CI:78.6-90.6%), respectively, in the detection of referable glaucoma when compared against final diagnosis following full glaucoma workup. True negative rate in definite non-glaucoma cases was 94.7% (95% CI: 87.2-97.9%). Amongst the false negatives were 4 early and 3 moderate glaucoma. When the same set of images provided to the AI was also provided to the specialists for image grading, specialists detected 60% (67/111) of true glaucoma cases versus a detection rate of 94% (104/111) by the AI. CONCLUSION: The AI tool showed robust performance when compared against a stringent benchmark. It had modest over-referral of normal subjects despite being challenged with fundus images alone. The next step involves a population-level assessment.

Diagnostic Accuracy of Automated Diabetic Retinopathy Image Assessment Softwares: IDx-DR and Medios Artificial Intelligence.

INTRODUCTION: Numerous studies have demonstrated the use of artificial intelligence (AI) for early detection of referable diabetic retinopathy (RDR). A direct comparison of these multiple automated diabetic retinopathy (DR) image assessment softwares (ARIAs) is, however, challenging. We retrospectively compared the performance of two modern ARIAs, IDx-DR and Medios AI. METHODS: In this retrospective-comparative study, retinal images with sufficient image quality were run on both ARIAs. They were captured in 811 consecutive patients with diabetes visiting diabetic clinics in Poland. For each patient, four non-mydriatic images, 45° field of view, i.e., two sets of one optic disc and one macula-centered image using Topcon NW400 were captured. Images were manually graded for severity of DR as no DR, any DR (mild non-proliferative diabetic retinopathy [NPDR] or more severe disease), RDR (moderate NPDR or more severe disease and/or clinically significant diabetic macular edema [CSDME]), or sight-threatening DR (severe NPDR or more severe disease and/or CSDME) by certified graders. The ARIA output was compared to manual consensus image grading (reference standard). RESULTS: On 807 patients, based on consensus grading, there was no evidence of DR in 543 patients (67%). Any DR was seen in 264 (33%) patients, of which 174 (22%) were RDR and 41 (5%) were sight-threatening DR. The sensitivity of detecting RDR against reference standard grading was 95% (95% CI: 91, 98%) and the specificity was 80% (95% CI: 77, 83%) for Medios AI. They were 99% (95% CI: 96, 100%) and 68% (95% CI: 64, 72%) for IDx-DR, respectively. CONCLUSION: Both the ARIAs achieved satisfactory accuracy, with few false negatives. Although false-positive results generate additional costs and workload, missed cases raise the most concern whenever automated screening is debated.

Impact of Monocular and Binocular Visual Function Parameters on Vision-Related Quality of Life in Glaucoma.

PRCIS: This study describes the impact of monocular (M/O) and binocular (B/O) visual function decline, primarily the contrast sensitivity (CS) and visual field (VF) defect severity and its location, on the subjective perception of quality of life (QoL) among the Indian glaucoma population with spared central acuity. AIM: To investigate the influence of M/O and B/O visual function parameters on vision-related QoL (VRQoL) in glaucoma with spared central visual acuity. MATERIALS AND METHODS: Glaucoma subjects underwent M/O and B/O visual acuity, CS assessment, followed by the M/O perimetry from which the integrated VF was estimated (B/O summation method). VRQoL was evaluated using the Glaucoma Quality Of Life-15 (GQL-15) and Visual Function Questionnaire-Utility Index (VFQ-UI) questionnaires. The relationship between CS and VF defect (VFD) with the composite VRQoL scores was analyzed. RESULTS: A total of 154 glaucoma subjects with a median age of 61 (range: 24-83) years were enrolled. Subjects with severe VFD reported poor composite scores for GQL-15 and VFQ-UI when compared with unilateral and mild groups ( P < 0.001, Dunn post hoc). Both the composite scores were negatively correlated with M/O and B/O CS and VF mean deviation ( r range: -0.3 to -0.5, P < 0.001, Spearman rank correlation). B/O VFD in the inferior central zone contributed to poor GQL-15 score [odds ratio: 1.14 (95% CI: 1.10-1.29), P = 0.04] irrespective of sex, whereas females with increasing B/O VFD reported poor QoL score in VFQ-UI [odds ratio: 4.09 (95% CI: 1.77-9.43), p=0.003]. CONCLUSIONS: Poor GQL-15 and VFQ-UI scores were reported with increasing disease severity. B/O VFD in the inferior central region was found to contribute predominantly to the poor GQL-15 scores while both disease severity and sex influenced VFQ-UI scores.

Low-vision intervention for oculocutaneous albinism in a Tertiary Eye Care Hospital in India.

PURPOSE: The objective of this study on patients with albinism in different age groups was to compare their level of visual impairment with the low-vision intervention (LVI) and its benefit. METHODS: The medical records of 72 patients with low vision secondary to albinism who were referred to the low vision care clinic from 2015 to 2017 were analyzed. This included the demographic profile such as age, gender, occupation, ocular history, visual acuity status, and type of low-vision device (LVD) preferred. The LVDs prescribed and its subsequent improvement was compared. RESULTS: In this data, 70 (97.2%) people had oculocutaneous albinism and 2 (2.8%) had ocular albinism. Majority of the patients had hyperopic astigmatism 42 (58.3%) and with-the-rule astigmatism 58 (93.5%). Presenting mean visual acuity for distance was noted to be 0.88 logMAR which improved to 0.83 logMAR with the help of spectacle correction. The most commonly prescribed LVD was a dome magnifier for 15 (34.9%) patients. In all the patients, there was statistically significant improvement (P < 0.05) in near vision with the help of LVDs. CONCLUSION: The study highlights the importance of appropriate LVI for each subdivided age group. Patients with albinism who have received medical and surgical treatment have no or a limited role in restoring useful vision.

Validation of a Simple-to-Use, Affordable, Portable Wavefront Aberrometry-Based Auto Refractometer in a Paediatric Population.

Purpose: InstaRef R20 is a handheld, affordable auto refractometer based on Shack Hartmann aberrometry technology. The study's objective was to compare InstaRef R20's performance for identifying refractive error in a paediatric population to that of standard subjective and objective refraction under both pre- and post-cycloplegic conditions. Methods: Refraction was performed using 1) standard clinical procedure consisting of retinoscopy followed by subjective refraction (SR) under pre- and post-cycloplegic conditions and 2) InstaRef R20. Agreement between both methods was evaluated using Bland-Altman analysis. The repeatability of the device based on three measurements in a subgroup of 20 children was assessed. Results: The refractive error was measured in 132 children (mean age 12.31 ± 3 years). The spherical equivalent (M) and cylindrical components (J0 and J45) of the device had clinically acceptable differences (within ±0.50D) and acceptable agreement compared to standard pre- and post-cycloplegic manual retinoscopy and subjective refraction (SR). The device agreed within ± 0.50D of retinoscopy in 67% of eyes for M, 78% for J0 and 80% for J45 and within ± 0.50D of SR in 70% for M and 77% for cylindrical components. Conclusion: InstaRef R20 has an acceptable agreement compared to standard retinoscopy in paediatric population. The measurements from this device can be used as a starting point for subjective acceptance. The device being simple to use, portable, reliable and affordable has the potential for large-scale community-based refractive error detection.

Validation of a simple-to-use, affordable, portable, wavefront aberrometry-based auto refractometer in the adult population: A prospective study.

BACKGROUND: Refraction is one of the key components of a comprehensive eye examination. Auto refractometers that are reliable and affordable can be beneficial, especially in a low-resource community setting. The study aimed to validate the accuracy of a novel wave-front aberrometry-based auto refractometer, Instaref R20 against the open-field system and subjective refraction in an adult population. METHODS: All the participants underwent a comprehensive eye examination including objective refraction, subjective acceptance, anterior and posterior segment evaluation. Refraction was performed without cycloplegia using WAM5500 open-field auto refractometer (OFAR) and Instaref R20, the study device. Agreement between both methods was evaluated using Bland-Altman analysis. The repeatability of the device based on three measurements in a subgroup of 40 adults was assessed. RESULTS: The refractive error was measured in 132 participants (mean age,30.53 ± 9.36 years, 58.3% female). The paired mean difference of the refraction values of the study device against OFAR was - 0.13D for M, - 0.0002D (J0) and - 0.13D (J45) and against subjective refraction (SR) was - 0.09D (M), 0.06 (J0) and 0.03D (J45). The device agreed within +/- 0.50D of OFAR in 78% of eyes for M, 79% for J0 and 78% for J45. The device agreed within +/- 0.5D of SR values for M (84%), J0 (86%) and J45 (89%). CONCLUSION: This study found a good agreement between the measurements obtained with the portable autorefractor against open-field refractometer and SR values. It has a potential application in population-based community vision screening programs for refractive error correction without the need for highly trained personnel.

Assessment of knowledge, attitude, and practice of glaucoma among different cadres of optometrists.

Purpose: To assess the level of knowledge, attitude, and clinical practice of glaucoma among optometry students and optometry practitioners with different years of clinical experience and academic background. Methods: A survey with 20 questions on knowledge, attitude, and practice (KAP) of glaucoma was prepared and self-administered to optometry students and optometry practitioners practicing in an eye hospital/clinic/optical with varied years of clinical experience and education qualification. Results: Among the 558 participants, 57% were optometry practitioners and 43% were students. The knowledge scores among optometry practitioners increased significantly with an increase in the years of clinical experience (P < 0.001). Participants with master's degrees scored higher than participants with bachelor's degrees (P = 0.12). There was no statistically significant difference in knowledge scores based on the type of clinical practice - hospital, private practice, or optical (P = 0.39). Practicing optometrists who performed slit-lamp examination, gonioscopy, IOP measurements, and disc evaluation for the detection of glaucoma had significantly higher knowledge scores than those who did not perform these tests in their practice (P < 0.05). A positive attitude toward glaucoma learning through workshops and hands-on training was reported by optometrists and students. Conclusion: Knowledge about glaucoma was good among optometrists and optometry students and was better among those who handled the diagnostics. All the optometrists had a positive attitude toward enhancing their practice through proper training.

Environmental factors in school classrooms: How they influence visual task demand on children.

BACKGROUND: The key visual factors in a classroom environment include the legibility, angle subtended at the eye, illumination, contrast, and colour of the visual task. The study evaluated the visual environmental factors in the school classrooms. MATERIALS AND METHODS: The distance Visual Acuity (VA) demand was evaluated based on the size of visual task i.e. the smallest size of chalkboard writing and its viewing distance. The environmental factors which can have an effect on the visibility in classrooms such as illuminance on the chalkboard and at student's desk, chalkboard contrast, light sources and the student's perception of their classroom visual environment were measured. To quantify the distance VA demand and to compare with a standard high contrast VA chart measure, a validation of the measurements was performed by chalkboard simulation experiment. The "acuity reserve" to be included to the measured distance VA demand was evaluated. RESULTS: We included twenty-nine classrooms of eight schools. The median distance VA threshold demand was 0.28 logMAR(0.25,0.45). The median illuminance on front desk position and chalkboard contrast was 130 lux(92,208) and 40(36,50) respectively with 62% classrooms having low illumination (<150lux). The acuity reserve evaluated to be included to the distance VA demand was 0.13logMAR and 0.29 logMAR in classrooms with optimal and low chalkboard illumination respectively which was based on the results of the simulation experiment. The median distance VA demand including the acuity reserve was 0.09 logMAR(-0.03,0.23) [Snellen Equivalent: 20/25(20/19,20/34)]. CONCLUSION: The study findings highlight the increased visual task demand in school classrooms and the need for appropriate seating arrangements in classrooms based on the visual acuity of children. The study emphasises regular audit of the classroom environment along with the school eye screening.

Construction and validation of logMAR visual acuity charts in seven Indian languages.

Purpose: The evaluation of visual impairment requires the measurement of visual acuity with a validated and standard logMAR visual acuity chart. We aimed to construct and validate new logMAR visual acuity chart in Indian languages (Hindi, Bengali, Telugu, Urdu, Kannada, Malayalam, and Assamese). Methods: The commonly used font in each language was chosen as the reference and designed to fit the 5 × 5 grid (Adobe Photoshop). Ten letters (easiest to difficult) around median legibility score calculated for each language based on the results of legibility experiment and differing by 10% were selected. The chart was constructed based on the standard recommendations. The repeatability of charts was tested and also compared with a standard English Early Treatment Diabetic Retinopathy Study (ETDRS) logMAR chart for validation. Results: A total of 14 rows (1.0 to -0.3 logMAR) with five letters in each line were designed with the range of row legibility between 4.7 and 5.3 for all the language charts. Each chart showed good repeatability, and a maximum difference of four letters was noted. The median difference in visual acuity was 0.16 logMAR for Urdu and Assamese chart compared to ETDRS English chart. Hindi and Malayalam chart had a median difference of 0.12 logMAR. When compared to the English chart a median difference of 0.14 logMAR was noted in Telugu, Kannada, and Bengali chart. Conclusion: The newly developed Indian language visual acuity charts are designed based on the standard recommendations and will help to assess visual impairment in people of these languages across the country.

Are children with low vision adapted to the visual environment in classrooms of mainstream schools?

PURPOSE: The study aimed to evaluate the classroom environment of children with low vision and provide recommendations to reduce visual stress, with focus on mainstream schooling. METHODS: The medical records of 110 children (5-17 years) seen in low vision clinic during 1 year period (2015) at a tertiary care center in south India were extracted. The visual function levels of children were compared to the details of their classroom environment. The study evaluated and recommended the chalkboard visual task size and viewing distance required for children with mild, moderate, and severe visual impairment (VI). RESULTS: The major causes of low vision based on the site of abnormality and etiology were retinal (80%) and hereditary (67%) conditions, respectively, in children with mild (n = 18), moderate (n = 72), and severe (n = 20) VI. Many of the children (72%) had difficulty in viewing chalkboard and common strategies used for better visibility included copying from friends (47%) and going closer to chalkboard (42%). To view the chalkboard with reduced visual stress, a child with mild VI can be seated at a maximum distance of 4.3 m from the chalkboard, with the minimum size of visual task (height of lowercase letter writing on chalkboard) recommended to be 3 cm. For 3/60-6/60 range, the maximum viewing distance with the visual task size of 4 cm is recommended to be 85 cm to 1.7 m. CONCLUSION: Simple modifications of the visual task size and seating arrangements can aid children with low vision with better visibility of chalkboard and reduced visual stress to manage in mainstream schools.

Do school classrooms meet the visual requirements of children and recommended vision standards?

BACKGROUND: Visual demands of school children tend to vary with diverse classroom environments. The study aimed to evaluate the distance and near Visual Acuity (VA) demand in Indian school classrooms and their comparison with the recommended vision standards. MATERIALS AND METHODS: The distance and near VA demands were assessed in 33 classrooms (grades 4 to 12) of eight schools. The VA threshold demand relied on the smallest size of distance and near visual task material and viewing distance. The logMAR equivalents of minimum VA demand at specific seating positions (desk) and among different grades were evaluated. The near threshold was converted into actual near VA demand by including the acuity reserve. The existing dimensions of chalkboard and classroom, gross area in a classroom per student and class size in all the measured classrooms were compared to the government recommended standards. RESULTS: In 33 classrooms assessed (35±10 students per room), the average distance and near logMAR VA threshold demand was 0.31±0.17 and 0.44±0.14 respectively. The mean distance VA demand (minimum) in front desk position was 0.56±0.18 logMAR. Increased distance threshold demand (logMAR range -0.06, 0.19) was noted in 7 classrooms (21%). The mean VA demand in grades 4 to 8 and grades 9 to 12 was 0.35±0.16 and 0.24±0.16 logMAR respectively and the difference was not statistically significant (p = 0.055). The distance from board to front desk was greater than the recommended standard of 2.2m in 27 classrooms (82%). The other measured parameters were noted to be different from the proposed standards in majority of the classrooms. CONCLUSION: The study suggests the inclusion of task demand assessment in school vision screening protocol to provide relevant guidance to school authorities. These findings can serve as evidence to accommodate children with mild to moderate visual impairment in the regular classrooms.