The COVID-19 pandemic brought about sudden, profound shifts in working practices, including in qualitative research, where telephone or virtual interviews became necessary alternatives to ...face-to-face interviews given COVID-19 distancing measures. In this reflection, we discuss our group’s transition to using telephone interviews to carry out an interpretative phenomenological analysis (IPA) study with 18 older adults living with age-related macular degeneration, a chronic, progressive eye disease causing central vision loss. Rather than focusing on the ‘pros and cons’ of the telephone modality compared to face-to-face interviews, we aim to provide a reflexive account of the telephone interview experience from both the researchers’ and participants’ perspectives within the unique context of the COVID-19 pandemic. Integrating these perspectives, we suggest that telephone interviews can generate rich data while being an accessible, comfortable mode of data collection for many participants. Provided there is reflection on how the context shapes the interview encounter, we suggest that telephone interviews can play an important role as part of a more pluralistic approach to qualitative data collection.
To evaluate changes in colour vision following intravitreal injection of Dexamethasone implant (Ozurdex) in patients with diabetic macular oedema (DMO). Both red-green (RG) and yellow-blue (YB) ...chromatic sensitivity were assessed using the Colour Assessment & Diagnosis (CAD) test which isolates the use of colour signals and provides age-corrected, statistical limits for normal trichromats. To determine whether colour changes and visual acuity (VA) post-treatment relate to central sub-field retinal thickness (CST).
Fourteen patients with DMO who were undergoing treatment with Ozurdex were recruited for this study. RG and YB colour thresholds were measured using the CAD test, best corrected visual acuity was assessed using the ETDRS chart and CST was measured using spectral domain optical coherence tomography (SD-OCT). All tests were performed monocularly at baseline and 24 weeks post injection.
All patients (n = 14 eyes), had significant loss of RG and YB chromatic sensitivity at baseline (p<0.05). The mean age was 56 ± 9.5 years. The age specific, monocular, upper normal limits for a 56 year old subject are 2.66 for RG and 2.85 for YB. In this study, the measured, pre injection thresholds (mean±SD) were 22.6 ± 11.3 for RG and 16.2 ± 3.76 for YB. There was significant improvement in RG threshold post injection (i.e., 19.2 ± 10.8 (p<0.05)). No significant changes were found in the YB thresholds with corresponding mean and range values of: 15.8 ± 4.6 (p = 0.23). CST pre-treatment was 542 ±135 μm. After treatment and by week 24 the CST values decreased to 435 ±127 μm.
RG colour thresholds provide a sensitive measure of functional change in diabetic subjects with macular oedema. The YB system is damaged severely in the DMO patients studied and shows little or no recovery post treatment. The improvement in VA and particularly in RG colour vision correlate well with the measured decrease in CST. The results suggest that the improvement in the RG chromatic sensitivity can provide a useful biomarker for monitoring the efficacy of treatment in DMO.
Purpose Rod and cone photoreceptor-specific tests can be time-consuming. A new non-invasive test is described. The test is based on the measurement of flicker modulation thresholds with rod- and ...cone-enhanced visual stimuli, which requires only minimum adaptation time. Here, we investigated how the rod-and cone-mediated flicker thresholds vary with age. Methods Monocular thresholds with rod and cone-enhanced stimuli were measured in 140 healthy adults, (age range: 18-75 years), foveally (0#176;) and at four parafoveal locations, at an eccentricity of 5#176; in each of the four quadrants using five, adaptive, interleaved staircases. Temporal frequencies, stimulus sizes, background luminance and spectral composition, were adjusted appropriately to achieve approximately 1 log unit separation in sensitivity between the rod- and cone-enhanced stimuli. Spectrally calibrated, 'neutral density' filters were used to enable adequate control of display luminance for rod enhanced stimuli. Results The magnitude of central and parafoveal rod thresholds was significantly higher than the central and parafoveal cone thresholds, respectively (p 45 years (Spearman correlation, rho = 0.74, p 0.001) compared to age less than or equal to 45 years (rho = 0.41, p 0.001). Conclusions Thresholds with rod- and cone-enhanced stimuli are largely invariant below 45 years of age and increase rapidly above this age. This age-wise normative database can be used as an effective functional-marker to assess photoreceptor sensitivities in retinal diseases.
Peekaboo Vision is an iPad grating acuity app built with typically developing children in mind. Given the ease of using this app in the pediatric age group, this study determined its clinical utility ...in children with Down syndrome. Two groups of participants (children with Down syndrome and age-matched controls) were included. Presenting binocular grating acuity was measured using Peekaboo Vision and Teller acuity cards II in random order. Parents' feedback about their child's engagement and time taken to complete each test was documented. Thirty-seven children with Down syndrome (males = 23; mean age = 8.1 ± 4.2 years) and 28 controls (males = 15; mean age = 8.71 ± 3.84 years) participated. Time taken to complete the tests was comparable (p = 0.83) in children with Down syndrome. Controls were significantly faster with Peekaboo Vision (p = 0.01). Mean logMAR acuities obtained with Peekaboo Vision (0.16 ± 0.34) and Teller acuity cards II (0.63 ± 0.34) were significantly different (p < 0.001) in children with Down syndrome (mean difference in acuities: -0.44 ± 0.38 logMAR (95% LoA: -1.18 to 0.3). For controls, the mean logMAR acuity with Peekaboo Vision (-0.13 ± 0.12) and Teller acuity cards II (0.12 ± 0.09) was also found to be significantly different (p < 0.001) (mean difference in acuities: -0.24 ± 0.14 logMAR (95% LoA: -0.51 to 0.03) Peekaboo Vision test can be used on children with Down syndrome. Peekaboo Vision and Teller acuity cards II can be used independently but not interchangeably. The differences in the acuity values between the two tests could be a result of the differences in the thresholding paradigms, different testing mediums and the range of acuities covered.
The Mallett Unit is a clinical test designed to detect the fixation disparity that is most likely to occur in the presence of a decompensated heterophoria. It measures the associated phoria, which is ...the "aligning prism" needed to nullify the subjective disparity. The technique has gained widespread acceptance within professions such as optometry, for investigating suspected cases of decompensating heterophoria; it is, however, rarely used by orthoptists and ophthalmologists. The aim of this study was to investigate whether fusional vergence reserves, measured routinely by both orthoptists and ophthalmologists to detect heterophoria decompensation, were correlated with aligning prism (associated phoria) in a normal clinical population.
Aligning prism (using the Mallett Unit) and fusional vergence reserves (using a prism bar) were measured in 500 participants (mean 41.63 years; standard deviation 11.86 years) at 40 cm and 6 m. At 40 cm a strong correlation (p<0.001) between base in aligning prism (Exo FD) and positive fusional reserves was found. Of the participants with zero aligning prism 30% had reduced fusional reserves. At 6 m a weak correlation between base out aligning prism (Eso FD) and negative fusional reserves was found to break (p = 0.01) and to recovery (p = 0.048). Of the participants with zero aligning prism 12% reported reduced fusional reserves.
For near vision testing, the strong inverse correlation between base in aligning prism (Exo FD) and fusional vergence reserves supports the notion that both measures are indicators of decompensation of heterophoria. For distance vision testing and for those patients reporting zero aligning prism further research is required to determine why the relationship appears to be weak/non-existent?
The aim of this study is to investigate whether subjects with central visual impairment (VI) show different reaching and grasping behavior for targets of different contrasts compared with visually ...normal age-matched subjects.
Reaching and grasping performance was measured in 14 subjects with VI and 14 normal subjects. Subjects were asked to pick up a cylindrical target. Three different targets were used: black (low contrast), white (high contrast), and transparent, placed against a black background. A motion analysis system (Vicon 460) recorded and reconstructed the hand and finger movements.
Significantly longer onset times, total movement duration, and time after maximum grip aperture were obtained for subjects with VI compared with normal subjects (p < 0.002). No significant differences existed in maximum velocity and grip aperture between the two groups for any of the targets.
Subjects with VI took longer to initiate and to complete the movement. Maximum velocity and grip aperture were not different suggesting that once the target was "seen" by subjects with VI performance was similar to normal subjects. Time after maximum grip aperture was longer in subjects with VI indicating the need for "online" modifications in these subjects. Contrast sensitivity was significantly correlated to more indices than visual acuity.
PDF
