Jeremiah K. H. Lim

Purpose: This study aimed to investigate whether short‐term inferior‐nasal gaze, commonly adopted during near work, alters macular perfusion differently from superior‐nasal gaze, and whether these gaze‐dependent changes vary between myopes and emmetropes. Methods: Twenty‐six healthy participants aged 18–35 years, comprising 14 emmetropes (−0.12 ± 0.26 D) and 12 myopes (−3.23 ± 2.22 D), underwent optical coherence tomography angiography to assess changes in the macular perfusion density (PD) during a 5‐min period of sustained superior‐nasal and inferior‐nasal gaze, compared with measurements captured in primary gaze. The choriocapillaris flow deficit density and PD of the deep choroid, and the retinal deep and superficial vascular plexuses were quantified across modified ETDRS regions over a 2 mm area centered on the fovea. Regional PD changes associated with oblique gaze direction and refractive group were examined using repeated measures ANOVA. Results: There was a significant gaze by region interaction for retinal deep vascular plexus PD ( p = 0.02), with PD reducing significantly by −1.6 ± 0.4 % in the temporal 1–2 mm region during inferior‐nasal gaze, while no significant changes were observed during superior‐nasal gaze in all regions ( p > 0.05). There was no significant main effect of gaze or gaze by region interaction on PD in any other chorioretinal layer, and PD responses to oblique gaze did not differ significantly between myopes and emmetropes (all p > 0.05). Conclusions: Reductions in macular PD of the retinal deep vascular plexus were observed associated with a brief period of inferior‐nasal gaze, whereas superior‐nasal gaze had no significant impact on the PDs. These findings may provide a better insight into the impact of near work activities on retinal perfusion which may be important for understanding mechanisms of myopia development.

Corneal foreign body removal is a common office-based procedure conducted by primary eye care practitioners globally. In Australia and New Zealand, optometry is a therapeutic profession capable of removing embedded corneal foreign bodies. In Australia, it has been estimated that ocular foreign bodies account for more than 44% of eye-related presentations to a hospital emergency department. Studies have shown that the majority of these patients can be effectively managed by the community optometrist, reducing the burden on hospital admissions. Regardless of the setting, the use of standardised terminology - recently expanded based on the IGATES recommendations, is essential when describing eye injuries. This review provides a comprehensive overview of the epidemiology, classification of trauma, assessment and removal procedure, tools involved and the post-removal therapeutic management of corneal foreign bodies. It reinforces the importance of the role of the primary eye care practitioner in the provision of accessible and timely care to patients with corneal foreign bodies.

Inherited retinal disease (IRD) refers to a heterogeneous group of genetic eye disease that causes progressive vision loss and was once regarded untreatable. However, regulatory approval for Luxturna (voretigene neparvovec-rzyl) for patients with biallelic mutation in the RPE65 gene has heralded new optimism for patients with the disease. One critical question in designing clinical trial in patients with IRD is choosing appropriate outcome measures to assess the retina, taking into consideration the slow disease progression and the inherent low vision associated with the disease. In this review, the functional and structural endpoints that have been utilised in human retinal gene therapy clinical trials in patient selection as well as measures of safety and efficacy are described. For clinicians, an appreciation of these specialised measures of eye health in a patient with IRD will enhance understanding of retinal health assessments, disease prognosis as well as facilitating discussions with patients potentially eligible for retinal gene therapy clinical trial.

The use of chloroquine or hydroxychloroquine can lead to both acute and chronic changes to both retinal structure and function.Chloroquine (CQ) and hydroxychloroquine (HCQ) have the potential for r...

The aim of this study was to review all the articles that have implemented patient-reported outcome measures (PROMs) to evaluate the quality of life (QoL) in corneal transplantation and discuss quality assessments of the PROMs. An extensive literature review was undertaken to identify all the studies that used PROMs to assess the QoL in corneal transplantation. Non-original or review articles, articles on other subject area and articles on cost-effectiveness/utility without PROM data/results were excluded. Each PROM was assessed against the following criteria: content development (item identification and item selection), psychometric properties, validity, reliability, and responsiveness. 425 articles were identified of which 35 articles were included in the final review. PROMs in corneal transplantation were used to (a) evaluate the QoL after surgery, (b) compare the QoL scores between different surgical techniques and (c) determine the relationship between QoL and objective measures such as visual acuity, visual field and stereoacuity. A total of 17 PROMs were used to assess QoL in corneal transplantation. Whilst this search did not produce any PROMs that were specifically designed to assess corneal transplantation, most studies were found to have employed the National Eye Institute Visual Function Questionnaire 25 (NEI VFQ 25). The Visual Function Index 14 (VF 14) performed better in the present quality assessment criteria compared to other PROMs, however, the NEI VFQ 25 and the VF 14 PROMs were not specifically developed for corneal transplantation and therefore the QoL assessment made using these PROMs may be incomplete. As improvements in various forms of lamellar transplantation surgery techniques such as UT-DSAEK and FT-DSAEK have resulted in better visual outcomes, improved graft survival and reduced complications, a corneal transplantation specific PROM will be useful in clinical settings to compare the outcomes of different surgical techniques from the patient perspective.

Hyperspectral imaging of the retina has recently been posited as a potentially useful form of spectroscopy of amyloid-beta (Aβ) protein in the eyes of those with Alzheimer’s disease (AD). The concept of using the retina as a biomarker for AD is an attractive one, as current screening tools for AD are either expensive or inaccessible. Recent studies have investigated hyperspectral imaging in Aβ models however these studies have been in younger mice. Here we characterised hyperspectral reflectance profile in 6 to 17 months old 5xFAD mice and compare this to Aβ in isolated preparations. Hyperspectral imaging was conducted across two preparations of Aβ using a custom built bench ophthalmoscope. In the in vitro condition, 1 mg of purified human Aβ42 was solubilised and left to aggregate for 72 h. This soluble/insoluble Aβ mixture was then imaged by suspending the solution at a pipette tip and compared against phosphate buffered saline (PBS) control (n = 10 ROIs / group). In the in vivo condition, a 5xFAD transgenic mouse model was used and retinae were imaged at the age of 6 (n = 9), 12 (n = 9) and 17 months (n = 8) with age matched wildtype littermates as control (n = 12, n = 13, n = 15 respectively). In the vitro condition, hyperspectral imaging of the solution showed greater reflectance compared with vehicle (p < 0.01), with the greatest differences occurring in the short visible spectrum (< 500 nm). In the in vivo preparation, 5xFAD showed greater hyperspectral reflectance at all ages (6, 12, 17 months, p < 0.01). These differences were noted most in the short wavelengths at younger ages, with an additional peak appearing at longer wavelengths (~ 550 nm) with advancing age. This study shows that the presence of Aβ (soluble/insoluble mixture) can increase the hyperspectral reflectance profile in vitro as well as in vivo. Differences were evident in the short wavelength spectrum (< 500 nm) in vitro and were preserved when imaged through the ocular media in the in vivo conditions. With advancing age a second hump around ~ 550 nm became more apparent. Hyperspectral imaging of the retina does not require the use of contrast agents and is a potentially useful and non-invasive biomarker for AD.

Alzheimer’s disease is characterized by the aberrant deposition of protein in the brain and is the leading cause of dementia worldwide. Increasingly, there have been reports of the presence of these protein hallmarks in the retina. In this study, we assayed the retina of 5xFAD mice, a transgenic model of amyloid deposition known to exhibit dementia-like symptoms with age. Using OCT, we found that the retinal nerve fiber layer was thinner in 5xFAD at 6, 12, and 17 months of age compared with wild-type littermates, but the inner plexiform layer was thicker at 6 months old. Retinal function showed reduced ganglion cell responses to light in 5xFAD at 6, 12, and 17 months of age. This functional loss was observed in the outer retina at 17 months of age but not in younger mice. We showed using immunohistochemistry and ELISA that soluble and insoluble amyloid was present in the retina and brain at all ages. In conclusion, we report that amyloid is present in brain and retina of 5xFAD mice and that the pattern of neuronal dysfunction occurs in the inner retina at the early ages and progresses to encompass the outer retina with age. This implies that the inner retina is more sensitive to amyloid changes in early disease and that the outer retina is also affected with disease progression.

Background: Amyloid-β soluble oligomers (Aβo) are believed to be the cause of the pathophysiology underlying Alzheimer’s disease (AD) and are normally detected some two decades before clinical onset of the disease. Retinal pathology associated with AD pathogenesis has previously been reported, including ganglion cell loss, accumulation of Aβ deposits in the retina, and reduction of nerve fiber layer thickness as well as abnormalities of the microvasculature. Objective: This study’s aim is to better understand the relationship between brain and retinal Aβo deposition and in particular to quantify levels of the toxic Aβo as a function of age in the retina of a rodent model of AD. Methods: Retinas and brain tissue from 5×FAD mice were stained with Congo red, Thioflavin-T (Th-T), and Aβ plaque-specific and Aβo-specific antibodies. Results: We show that retinas displayed an age-dependent increase of Th-T-specific amyloid fibrils. Staining with anti-Aβ antibody confirmed the presence of the Aβ plaques in all 5×FAD retinas tested. In contrast, staining with anti-Aβo antibody showed an age-dependent decrease of retinal Aβo. Of note, Aβo was observed mainly in the retinal nuclear layers. Finally, we confirmed the localization of Aβo to neurons, typically accumulating in late endosomes, indicating possible impairment of the endocytic pathway. Conclusion: Our results demonstrate the presence of intraneuronal Aβo in the retina and its accumulation inversely correlated with retinal Aβ plaque deposition, indicating an age-related conversion in this animal model. These results support the development of an early AD diagnostic test targeting Aβo in the eye.