Enablers and Barriers to Deployment of Smartphone-Based Home Vision Monitoring in Clinical Practice Settings.

IMPORTANCE: Telemedicine is accelerating the remote detection and monitoring of medical conditions, such as vision-threatening diseases. Meaningful deployment of smartphone apps for home vision monitoring should consider the barriers to patient uptake and engagement and address issues around digital exclusion in vulnerable patient populations. OBJECTIVE: To quantify the associations between patient characteristics and clinical measures with vision monitoring app uptake and engagement. DESIGN, SETTING, AND PARTICIPANTS: In this cohort and survey study, consecutive adult patients attending Moorfields Eye Hospital receiving intravitreal injections for retinal disease between May 2020 and February 2021 were included. EXPOSURES: Patients were offered the Home Vision Monitor (HVM) smartphone app to self-test their vision. A patient survey was conducted to capture their experience. App data, demographic characteristics, survey results, and clinical data from the electronic health record were analyzed via regression and machine learning. MAIN OUTCOMES AND MEASURES: Associations of patient uptake, compliance, and use rate measured in odds ratios (ORs). RESULTS: Of 417 included patients, 236 (56.6%) were female, and the mean (SD) age was 72.8 (12.8) years. A total of 258 patients (61.9%) were active users. Uptake was negatively associated with age (OR, 0.98; 95% CI, 0.97-0.998; P = .02) and positively associated with both visual acuity in the better-seeing eye (OR, 1.02; 95% CI, 1.00-1.03; P = .01) and baseline number of intravitreal injections (OR, 1.01; 95% CI, 1.00-1.02; P = .02). Of 258 active patients, 166 (64.3%) fulfilled the definition of compliance. Compliance was associated with patients diagnosed with neovascular age-related macular degeneration (OR, 1.94; 95% CI, 1.07-3.53; P = .002), White British ethnicity (OR, 1.69; 95% CI, 0.96-3.01; P = .02), and visual acuity in the better-seeing eye at baseline (OR, 1.02; 95% CI, 1.01-1.04; P = .04). Use rate was higher with increasing levels of comfort with use of modern technologies (ß = 0.031; 95% CI, 0.007-0.055; P = .02). A total of 119 patients (98.4%) found the app either easy or very easy to use, while 96 (82.1%) experienced increased reassurance from using the app. CONCLUSIONS AND RELEVANCE: This evaluation of home vision monitoring for patients with common vision-threatening disease within a clinical practice setting revealed demographic, clinical, and patient-related factors associated with patient uptake and engagement. These insights inform targeted interventions to address risks of digital exclusion with smartphone-based medical devices.

Antimicrobial Activity and Antiadherent Effect of Peruvian Psidium guajava (Guava) Leaves on a Cariogenic Biofilm Model.

AIM: Phytomedicine has been commonly practiced as a form of traditional medicine in various cultures for the treatment of oral diseases. Recently, it has gained importance as an alternative to conventional treatment. Several extracts of plants and fruits have been recently evaluated for their potential activity against microorganisms involved in the development of dental caries. The purpose of this study was to evaluate the antimicrobial activity and antiadherent effect of the crude organic extract (COE) and three partitions (aqueous, butanolic, and chloroformic) of Psidium guajava (guava) leaves on a cariogenic biofilm model. MATERIALS AND METHODS: Guava leaves were obtained from the mountains of northern Peru, where they grow wild and free of pesticides. The antimicrobial activity of the COEs and partitions against Streptococcus mutans and Streptococcus gordonii was determined by measuring the inhibition halos, while the effect on biofilm adhesion was determined by measuring the optical density using spectrophotometry. RESULTS: An antibacterial effect of the COE and chloroformic partition against S. gordonii (p < 0.05) was found, as was a significant effect on biofilm adherence, with a minimum inhibitory concentration (MIC) of 0.78 mg/mL, which was maintained throughout the 7 days of evaluation. CONCLUSION: We conclude that the COEs and their chloroformic partition have antimicrobial and antibiotic effects against this strain of S. gordonii, making them of particular interest for evaluation as a promising alternative for the prevention of dental caries. CLINICAL SIGNIFICANCE: By knowing the antimicrobial effect of Psidium guajava, this substance can be effectively used in products aimed to prevent dental caries and periodontal disease.

Example of monitoring measurements in a virtual eye clinic using 'big data'.

AIM: To assess the equivalence of measurement outcomes between patients attending a standard glaucoma care service, where patients see an ophthalmologist in a face-to-face setting, and a glaucoma monitoring service (GMS). METHODS: The average mean deviation (MD) measurement on the visual field (VF) test for 250 patients attending a GMS were compared with a 'big data' repository of patients attending a standard glaucoma care service (reference database). In addition, the speed of VF progression between GMS patients and reference database patients was compared. Reference database patients were used to create expected outcomes that GMS patients could be compared with. For GMS patients falling outside of the expected limits, further analysis was carried out on the clinical management decisions for these patients. RESULTS: The average MD of patients in the GMS ranged from +1.6dB to -18.9dB between two consecutive appointments at the clinic. In the first analysis, 12 (4.8%; 95% CI 2.5% to 8.2%) GMS patients scored outside the 90% expected values based on the reference database. In the second analysis, 1.9% (95% CI 0.4% to 5.4%) GMS patients had VF changes outside of the expected 90% limits. CONCLUSIONS: Using 'big data' collected in the standard glaucoma care service, we found that patients attending a GMS have equivalent outcomes on the VF test. Our findings provide support for the implementation of virtual healthcare delivery in the hospital eye service.

Development of a Pediatric Visual Field Test.

PURPOSE: We describe a pediatric visual field (VF) test based on a computer game where software and hardware combine to provide an enjoyable test experience. METHODS: The test software consists of a platform-based computer game presented to the central VF. A storyline was created around the game as was a structure surrounding the computer monitor to enhance patients' experience. The patient is asked to help the central character collect magic coins (stimuli). To collect these coins a series of obstacles need to be overcome. The test was presented on a Sony PVM-2541A monitor calibrated from a central midpoint with a Minolta CS-100 photometer placed at 50 cm. Measurements were performed at 15 locations on the screen and the contrast calculated. Retinal sensitivity was determined by modulating stimulus in size. To test the feasibility of the novel approach 20 patients (4-16 years old) with no history of VF defects were recruited. RESULTS: For the 14 subjects completing the study, 31 ± 15 data points were collected on 1 eye of each patient. Mean background luminance and stimulus contrast were 9.9 ± 0.3 cd/m2 and 27.9 ± 0.1 dB, respectively. Sensitivity values obtained were similar to an adult population but variability was considerably higher - 8.3 ± 9.0 dB. CONCLUSIONS: Preliminary data show the feasibility of a game-based VF test for pediatric use. Although the test was well accepted by the target population, test variability remained very high. TRANSLATIONAL RELEVANCE: Traditional VF tests are not well tolerated by children. This study describes a child-friendly approach to test visual fields in the targeted population.

Corneal biomechanical properties and their correlates with refractive error.

PURPOSE: The aim was to study the link between refractive error and corneal biomechanical properties. METHODS: Corneal hysteresis and corneal resistance factor were measured using the Ocular Response Analyser in 117 participants. The spherical equivalent refractive error of the participants ranged between -9.00 and +3.00 D. RESULTS: Corneal hysteresis and corneal resistance factor showed a considerable degree of variability between individuals. Corneal hysteresis was not found to correlate significantly with refractive error (p = 0.82). Corneal resistance factor showed a weak but significant correlation with spherical equivalent refractive error (r(2) = 0.04; p = 0.03), with myopic participants exhibiting a higher corneal resistance factor compared with non-myopes. CONCLUSIONS: Refractive error accounted for four per cent of the variance in corneal resistance factor measurements, indicating that patients with mild to moderate myopia have higher corneal resistance compared with non-myopes.

Corneal biomechanical properties measured with the Ocular Response Analyser in a myopic population.

PURPOSE: To explore the possible association between myopia and corneal biomechanical properties in a Caucasian population, and the correlations between the properties of right and left eyes. METHODS: Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using the Ocular Response Analyser (ORA) in both eyes of 95 normal adult subjects aged between 19 and 48 years. The spherical equivalent refractive errors of the participants ranged from 0.25 to -14.00 D. The mean CH and CRF values for the right and left eyes were recorded for each subject. CH and CRF data were compared between different refractive groups. RESULTS: CH was found to be slightly lower in high myopes (>-6.00 D, mean CH 10.0 ± 1.2 mmHg) in comparison to moderate myopes (>-3.00 to -6.00 D, 10.1 ± 1.4 mmHg) and emmetropes and low myopes (+0.25 to -2.75 D, 10.9 ± 1.5 mmHg). The decrease in CH with the degree of myopia was about 0.13 mmHg per D or roughly 1% per D (r(2) = 0.084, p < 0.001). Inter-subject variations were much greater than any systematic changes. CRF was not correlated with refractive error (r(2) = 0.001, p = 0.66). Although the refractive error was highly correlated between the two eyes (r(2) = 0.89, p < 0.001), CH and CRF showed a lower inter-ocular correlation (r(2) = 0.68, p < 0.001 and r(2) = 0.77, p < 0.001 respectively). CONCLUSIONS: These findings may indicate that the viscoelastic properties of the cornea are altered to a minor extent in myopia. However, in this normal population, any overall systematic changes in CH and CRF with refractive error were small in comparison with the considerable inter-subject scatter at any level of refraction.

Repeatability of oculus pentacam metrics derived from corneal topography.

PURPOSE: To estimate the variability of Scheimpflug imaging measurements over a 1-week period and to determine the impact of age on the measurements and on the variability of the parameters in the study. METHODS: Three consecutive measurements of anterior and posterior corneal P values (CPVs), central corneal radii (horizontal and vertical), and sagittal corneal radii (at the apex and along an 8-mm diameter ring) were performed on one eye of 23 healthy subjects. Measurements were obtained at 3 different sessions with intervals of a few seconds, 1 hour, and 1 week, under scotopic conditions and immediately after a blink. RESULTS: In general, no clinically or statistically significant differences were found in within-subjects variance between the three time scales. Confidence limits from Bland and Altman analysis within the first session, and between the first and second sessions, and between the first and third sessions ranged between +/-0.09 and +/-0.18 for anterior and posterior CPV, and between +/-0.03 mm and +/-0.27 mm for anterior and posterior corneal radii (central and sagittal radii). Anterior and posterior corneal measurements and the variability of these measurements were not found to change significantly as a function of age. CONCLUSION: The Oculus Pentacam provides repeatable measures of the metrics derived from corneal topography over the tested time scales. In subjects aged from 19 to 40 years, topography measurements and their respective variability did not seem to change significantly with age.

Repeatability of corneal and ocular aberration measurements and changes in aberrations over one week.

BACKGROUND: Both Shack-Hartmann aberrometry (IRX3, Imagine Eyes, Orsay, France) and Scheimpflug photography (Oculus Pentacam, Oculus Inc Wetzlar, Germany) are known to provide repeatable measurements. The variability in measurements of corneal and ocular aberrations obtained with these instruments over one week had not been assessed. The aim was to study the variability in corneal and ocular aberrations in the human eye over one week and to determine the impact of age on corneal and crystalline lens aberrations and on the variability of these measurements. METHODS: Monochromatic ocular aberrations were measured with the IRX3 and monochromatic corneal aberrations were measured using Scheimpflug photography on one eye of 23 normal subjects at periods of a few seconds, one hour and one week after the initial measurement. RESULTS: No significant differences were found between the initial aberrations and aberrations measured at 59 +/- 24 seconds, 1.10 +/- 0.24 hours and 7.11+/- 0.31 days later. Analysis with Bland and Altman plots showed that measurements with both instruments were highly repeatable over the times studied. There was no relationship between age and the variance of corneal and ocular aberrations (higher order, spherical and coma aberrations). Corneal spherical aberration did not show a significant correlation with age, whereas the lens aberrations changed from being negative in the younger age groups to positive in the older age group, however, these differences failed to reach statistical significance (p > 0.05). CONCLUSION: The variability found in all the measurements was small and not clinically significant and could be attributable to instrument noise, changes in the tear film and to small fixational eye movements.

Repeatability of corneal thickness measured using an Oculus Pentacam.

PURPOSE: To evaluate the repeatability of corneal thickness measurements over time, obtained with an Oculus Pentacam. METHODS: Measurements of corneal thickness (apical and peripheral) were performed at three different sessions in one eye of 23 healthy subjects, using an Oculus Pentacam instrument. In each session, three consecutive measurements were taken (without realignment) by the same observer. Measurements were performed, immediately after a blink. RESULTS: Mean values obtained were in agreement with published literature values for central corneal thickness (mean +/- SEM: 546.23 +/- 5.24 microm for first session over the first 1 min, 545.13 +/- 5.49 microm for second session 1 h later, and 543.23 +/- 4.96 microm for the third session measured 1 week later). The data showed an increase in corneal thickness towards the periphery with a decrease in intraobserver reproducibility. The confidence limits in the Bland and Altman charts for pachymetry at the corneal apex ranged between -10.91 microm and 13.00 microm within the first session measured over the first 1 min, -13.43 microm to 11.23 microm between the first and second sessions after 1 h and -11.99 microm to 10.02 microm between the first and third sessions after 1 week. The confidence limits were found to increase towards the peripheral cornea. There was no significant difference in within-subjects variance between the three time scales (p > 0.05 for all parameters measured). CONCLUSION: Our data showed that the Oculus Pentacam provides repeatable measures of corneal thickness when measured within a few seconds, after 1 h, and 1 week.

Perimetric sensitivity and response variability in glaucoma with single-stimulus automated perimetry and multiple-stimulus perimetry with verbal feedback.

PURPOSE: To measure perimetric sensitivity and response variability of glaucomatous patients with single-stimulus automated perimetry (SSAP) and multiple-stimulus perimetry (MSP) with verbal feedback. METHODS: Frequency-of-seeing (FOS) data were collected from the same four visual field locations (normal and reduced sensitivity) in one eye of 10 glaucoma patients, using SSAP and MSP. The SSAP technique was similar to that used in routine clinical perimetry while the MSP technique required the patient to verbally report the positions of the seen stimuli (0-4, with no more than 1 in each quadrant) after each presentation. At each test location, stimuli (0.5 degrees , 200 ms) were repeatedly presented at five or more intensities around the estimated threshold. FOS curves (logistic) were determined using a maximum likelihood method and the threshold sensitivity (50% seen) and response variability (20-80% seen range) were compared between the two perimetric techniques. RESULTS: There was an increase in sensitivity (mean = 1.9 dB, P < 0.01, Wilcoxon) and reduction in variability (mean range reduced from 3.7 to 2.5 dB, P < 0.01, Wilcoxon) with MSP. The increase in sensitivity with MSP varied between patients (P < 0.001, one-way anova) with the mean MSP-SSAP sensitivity per eye ranging from 0.1 to 4.8 dB. CONCLUSION: Patients have a higher sensitivity and less variability in their visual field when tested with MSP with verbal feedback than with SSAP. These differences vary between patients and a likely explanation is the better maintenance of attention with MSP and verbal feedback. This finding demonstrates how the variability found in routine clinical perimetry can be reduced through changes to the way in which the stimuli are presented and the way in which the patient responds.