OCTA biomarkers in adults aged 50 and above: a prospective and cross-sectional community-based study.

BACKGROUND/AIMS: To assess the normative values and parameters of optical coherence tomography angiography (OCTA) influencing the best corrected visual acuity (BCVA) in adults aged 50 and above. METHODS: This was a prospective cross-sectional study from an eye screening programme in Hong Kong for 4188 citizens aged 50 and above. Images were analysed using a validated quantification software calculating vessel density and capillary perfusion density (CPD), along with other OCTA parameters, such as the foveal avascular zone area (FAZ) and circularity. OCTA data was collected from May 2019 to December 2020, including a total of 4188 healthy eyes from 4188 subjects. RESULTS: Mean superficial vessel density (MSVD) was 14.48 ± 3.60 mm- 1, while the mean capillary perfusion density (MCPD) was 0.41 ± 0.06. Multivariate analysis revealed ageing (ß = 0.321, p < 0.001), being male (ß=-0.089, p < 0.001), having a high body mass index (BMI) (ß = 0.039, p = 0.006), high FAZ area and low FAZ circularity (ß = 0.039 and - 0.034, p = 0.01 and 0.024 respectively), low MSVD in the outer ring (ß=-0.513, p < 0.001), specifically in the nasal and temporal outer quadrants (ß = -0.226 and - 0.259, p < 0.001 for both), and low MCPD in the outer superior quadrant (ß= -0.123, p = 0.016) being independently associated with BCVA. CONCLUSION: High FAZ area and low FAZ circularity, low MSVD in the outer ring, specifically the nasal and temporal outer quadrants, and low MCPD in the outer superior quadrant can be used as biomarkers in predicting a low visual acuity in adults aged 50 and above.

Premium intraocular lens implantation in eyes with vitrectomy done.

PURPOSE: Phacoemulsification with premium intraocular lens (IOL) implantation has been increasingly popular in the recent years. However, it is not commonly implanted in eyes who had underwent previous vitrectomy surgery as the contrast sensitivity is thought to be reduced and surgeons are worried about poor visualization of the posterior segment after implantation. Since cataract and vitreoretinal diseases often coexist, premium IOLs should be a considerable option for implantation in carefully selected cases. This study aims at reporting the postoperative near and distance visual acuity and subjective quality of vision in eyes with premium IOLs implantation and vitrectomy done. METHODS: Twenty eyes with posterior vitrectomy and premium IOL implantation from 2006 to 2018 were included. Fourteen eyes were included in Group 1 with patients who underwent a combined phacovitrectomy surgery in the same setting, and six eyes were included in Group 2 with patients who received premium IOL implantation after previous posterior vitrectomy. RESULTS: Both the postoperative corrected distance and near visual acuity at 1 month, 3 month and 1 year are improved in both groups. The subjective quality of vision as graded by the National Eye Institute Refractive Error Quality of Life Instrument-42 questionnaire also showed high patient satisfaction in both groups. CONCLUSION: We conclude that the presence of a multifocal IOL does not impede visualization of the posterior segment during vitrectomy surgery and surgical complications were not raised. With careful patient selection and preoperative assessment, premium IOLs can be a considerable option in patients requiring posterior vitrectomy. TRIAL REGISTRATION: Retrospectively registered with the HKSH Medical Group Research Committee (Ref No. RC-2019-31, Date of registration: December 13, 2019).

Nutraceuticals for Diabetic Retinopathy: Recent Advances and Novel Delivery Systems.

Diabetic retinopathy (DR) is a major vision-threatening disease among the working-age population worldwide. Present therapeutic strategies such as intravitreal injection of anti-VEGF and laser photocoagulation mainly target proliferative DR. However, there is a need for early effective management in patients with early stage of DR before its progression into the more severe sight-threatening proliferative stage. Nutraceuticals, natural functional foods with few side effects, have been proposed to be beneficial in patients with DR. Over the decades, many studies, either in vitro or in vivo, have demonstrated the advantages of a number of nutraceuticals in DR with their antioxidative, anti-inflammatory, neuroprotective, or vasoprotective effects. However, only a few clinical trials have been conducted, and their outcomes varied. The low bioavailability and instability of many nutraceuticals have indeed hindered their utilization in clinical use. In this context, nanoparticle carriers have been developed to deliver nutraceuticals and to improve their bioavailability. Despite its preclinical nature, research of interventive nutraceuticals for DR may yield promising information in their clinical applications.

Ocular manifestations and diagnosis of tuberculosis involving the uvea: a case series.

BACKGROUND: Ocular tuberculosis (TB) affects 1-2% of patients with TB, with TB uveitis being the most common. This series aims to look at different manifestations of tuberculosis associated uveitis and the different tests used to make a presumptive or definitive diagnosis. METHODS: Patients diagnosed with TB related uveitis in Hong Kong SAR between 2017 and 2020 were reviewed. Demographics, clinical features, investigations and treatments of patients were collected. RESULTS: Fifteen eyes in 10 patients with a mean age 57.30 ± 10.17 years were included. The ocular manifestations on presentation included anterior uveitis (50%), posterior uveitis (40%) and panuveitis (10%), where 70% of them were unilateral and 30% were bilaterally infected; on subsequent visits the manifestations further developed into posterior uveitis (40%), panuveitis (40%) and anterior uveitis (20%), where 50% of them were unilateral and 50% bilateral infected. Tuberculosis tests were positive in 5 out of 7 Mantoux tests, 4 out of 4 T-SPOT TB tests, 3 out of 4 QuantiFERON-TB gold tests, 1 out of 1 lymph node biopsy, 0 out of 9 chest x-rays, and no aqueous fluid polymerase chain reaction (PCR) was tested. Vision impairing complications were seen in 6 patients where retinal vasculitis was most commonly seen. With anti-TB treatment prescribed in 9 patients, side effects occurred in 5 patients, including ocular hypertension, disc swelling, and hepatitis. CONCLUSIONS: Ocular TB infections may manifest in various forms, and can involve different parts of the eye. Bilateral involvement of TB is commonly presented, and both eyes should be evaluated at every follow up. When TB is suspected in a patient, diagnostic confirmation requires multimodal investigations where a negative chest x-ray is not useful in ruling out ocular TB infections, especially in an endemic region like Hong Kong. In these patients, it is crucial to have a high index of suspicion for TB, even when they do not demonstrate classical respiratory signs and symptoms of TB.

mTOR Signalling Pathway: A Potential Therapeutic Target for Ocular Neurodegenerative Diseases.

Recent advances in the research of the mammalian target of the rapamycin (mTOR) signalling pathway demonstrated that mTOR is a robust therapeutic target for ocular degenerative diseases, including age-related macular degeneration (AMD), diabetic retinopathy (DR), and glaucoma. Although the exact mechanisms of individual ocular degenerative diseases are unclear, they share several common pathological processes, increased and prolonged oxidative stress in particular, which leads to functional and morphological impairment in photoreceptors, retinal ganglion cells (RGCs), or retinal pigment epithelium (RPE). mTOR not only modulates oxidative stress but is also affected by reactive oxygen species (ROS) activation. It is essential to understand the complicated relationship between the mTOR pathway and oxidative stress before its application in the treatment of retinal degeneration. Indeed, the substantial role of mTOR-mediated autophagy in the pathogenies of ocular degenerative diseases should be noted. In reviewing the latest studies, this article summarised the application of rapamycin, an mTOR signalling pathway inhibitor, in different retinal disease models, providing insight into the mechanism of rapamycin in the treatment of retinal neurodegeneration under oxidative stress. Besides basic research, this review also summarised and updated the results of the latest clinical trials of rapamycin in ocular neurodegenerative diseases. In combining the current basic and clinical research results, we provided a more complete picture of mTOR as a potential therapeutic target for ocular neurodegenerative diseases.

The role of anti-vascular endothelial growth factor in treatment of retinopathy of prematurity-a current review.

The review aims to evaluate the uses of conventional laser therapy and intravitreal injection of various anti-VEGF in terms of efficacy and side effects for the treatment of retinopathy of prematurity. A literature search of the publication, concerning conventional laser treatment and intravitreal injection of anti-VEGF for ROP. A total of 40 articles were reviewed after curation by the authors for relevance. Intravitreal anti-VEGF showed better ocular efficacy in zone I ROP while laser therapy had a lower recurrence rate in zone II. Comparing the two mainstay anti-VEGF agents, bevacizumab showed lower ROP recurrence rate than ranibizumab. Anti-VEGF has a higher chance in developing persistent peripheral avascularisation compared to conventional laser therapy, but a lower chance of developing high myopia. Ranibizumab has a lower systemic absorption than bevacizumab, despite having no difference in the incidence of persistent peripheral avascularisation. In conclusion, it is advised that intravitreal anti-VEGF should be used as the first-line treatment for zone I ROP while laser therapy should be the mainstay for zone II ROP owing to the different pathogenetic mechanisms. In patients with recurrence after initial anti-VEGF injection, that given ranibizumab may opt to repeat the injection while that given bevacizumab should consider supplement laser ablative treatment.

Management of Patients with Newly Diagnosed Diabetic Mellitus: Ophthalmologic Outcomes in Intensive versus Conventional Glycemic Control.

BACKGROUND AND OBJECTIVE: Diabetic retinopathy, a microvascular complication of diabetes mellitus, is one of the most important causes of visual loss in developed countries. Our objective is to evaluate the efficacy of intensive versus conventional glycemic control of type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) patients in terms of ophthalmologic outcome, pathogenesis of the early worsening of diabetic retinopathy, risk factors for early worsening and diabetic retinopathy progression. METHODS: A literature search on publications concerning glycaemic control in diabetic retinopathy and management of newly diagnosed diabetes mellitus by intensive versus conventional glycaemic control. RESULTS: A total of 22 articles were reviewed after curation by the authors for relevance. Nineteen articles are randomized control trial, 2 articles are observational studies and 1 is clinical trial. Fifteen articles investigated the glycaemic control in T1DM-related diabetic retinopathy and 8 on T2DM-related diabetic retinopathy. The level of glycemia (in terms of HbA1c level) is significantly related to the diabetic retinopathy progression in both T1DM and T2DM. Intensive glycemic control was found to reduce the development of severe diabetic retinopathy, including severe non-proliferative diabetic retinopathy, neovascularization, clinically significant macular edema and loss of vision. Early worsening of diabetic retinopathy commonly occurs during the first year of intensive treatment, especially those initially present with proliferative or severe non-proliferative retinopathy. However, most patients with early worsening can recover and their long-term ophthalmologic outcomes are better when compared to conventional glycemic control. CONCLUSION: The current guideline on HbA1c level is considered sufficient for the minimization of diabetic retinopathy progression. More frequent monitoring for early worsening should be recommended for newly diagnosed diabetes cases already presenting with retinopathy.