JOURNAL ABSTRACTS
The Longitudinal Follow-up of a Newly Proposed OCTA Imaging Finding (SSPiM) and the Importance of it as a New Biomarker for Treatment Response in Diabetic Macular Edema
OCTA offers a noninvasive modality to detect flow of erythrocytes in the retinal and choroidal vasculature. As such, the imaging technology offers important insights into diabetic macular edema (DME) and diabetic retinopathy. A newly recognized imaging finding is highlighted in this study called suspended scattering particles in motion (SSPiM). SSPiM is an artifact on OCTA associated with motion contrast created by non-erythrocyte particles, suspected to be lipid and protein-containing macromolecules. On OCT B scans, SSPiM are hyperreflective fluid filled spaces that on OCTA show false flow signals. This prospective study was designed to evaluate the frequency of SSPiM in DME and compare treatment response in eyes with vs without. A total of 109 eyes with DME of 109 patients were followed over 6 months. SSPiM was present in 34.9%, half of which had moderate NPDR and the rest had severe NPDR or PDR. SSPiM was most often (81.6%) noted in the outer nuclear layer. Over the follow up course, the SSPiM+ group had a poorer anti-VEGF treatment response rate with 33.3% decreasing in central subfoveal thickness, as compared to the SSPiM- group at 62.5%. In 7 of 36 patients SSPiM disappeared over follow-up. Of those, 4 developed hard exudate localized to the same area. This study, though small, reveals more insights into a new OCT biomarker, SSPiM.
Genç G, Yanık Ö, Demirel S, et al. The longitudinal follow-up of a newly proposed OCTA imaging finding (SSPiM) and the importance of it as a new biomarker for treatment response in diabetic macular edema. Graefes Arch Clin Exp Ophthalmol. 2024 Mar 26. doi: 10.1007/s00417-024-06457-2. Epub ahead of print.
Exploring Patient Demographics and Presence of Retinal Vascular Disease in Paracentral Acute Middle Maculopathy
Paracentral acute middle maculopathy is an SD-OCT finding of hyperreflective bands at the inner nuclear layer that later progresses to atrophy and thinning. There are many reports on PAMM in the literature finding it linked with retinal vascular disease (RVD) and attributing PAMM to ischemia and/or infarction originating from the intermediate or deep capillary plexus. This study was designed to explore a large population of PAMM for insights into the epidemiology, patient demographics, and visual consequences.
This was a retrospective cohort study record performed at Moorfields Eye Hospital of adult patients with a diagnosis of PAMM. From the chart and imaging review, ultimately 78 patient records consistent with PAMM were identified. The median age of the cohort was 54.5 years with 62.8% male. The ethnic breakdown was 37 patients (47.4%) identified Caucasian, 4 Afro-Caribbean, 5 South Asian, 15 other and 17 not specified.
Half (51.3%) of patient records were confirmed as an isolated PAMM event, meaning no coexistent RVD. Systemic comorbidities were found in many of these isolated cases including: 52.5% HTN, 20% history of major adverse cardiovascular event, 20% with sickle cell disease, 17.5% with DM, 12.5% hypercholesterolemia, and 7.5% with migraine. Furthermore, 1 patient was pregnant, 1 developed PAMM 4 days post COVID-19 BioNTech vaccination and 1 patient associated with amphetamine use. The remaining cohort, 38 patients, had associated RVD breaking down into 20 with RVO, 16 with RAO, and 2 with combined RAO and RVO.
This study boasts the largest collection of PAMM in a multiethnic cohort. Of significance, the isolated PAMM group showed a higher prevalence of stroke or myocardial infarction (p=.04) and sickle cell disease (p=.04) as compared the PAMM group with RVD. This may indicate a need for further systemic evaluation in such cases. Across both groups, PAMM was associated with good BCVA improvement during follow-up.
Limoli C, Raja LD, Wagner SK, Ferraz D, Bolz M, Vujosevic S, Nucci P, Nicholson L, Keane PA, Khalid H, Huemer J. Exploring Patient Demographics and Presence of Retinal Vascular Disease in Paracentral Acute Middle Maculopathy. Am J Ophthalmol. 2024 Apr;260:182-189.
Incidence of Central Retinal Artery Occlusion Peaks in Winter Season
Research has shown that the incidence of cerebral stroke peaks in winter months. This article investigates whether or not the same holds true for central retinal artery occlusion (CRAO), which is an ocular form of stroke affecting 1.3 to 1.8 per 100,000 people per year. A retrospective chart review covering 15 years from 2008 to 2022, was conducted at University Eye Hospital in Tubingen, Germany. A total of 432 patients were diagnosed with CRAO during that time. Like cerebral stroke, the incidence of CRAO was also found to be highest in the winter months, with a peak in February of 1.55 times the incidence found at the low point of the summer months, which was in June. The authors speculate on possible associations with the winter months which could contribute to the increased prevalence of CRAO. Temperatures are lower in the winter, which may potentially have a role. In addition, air pollutants are found at a higher volume in the winter months. Specifically, in this review, the increased winter incidence of CRAO correlated with higher nitrous oxide and higher fine particulate matter. Cold air stays close to the ground compared to warm air, thus making it more difficult for pollutants to disperse. The amount of ozone and the amount of course particulate matter did not prove to show correlation.
Gassel CJ, Andris W, Poli S, Bartz-Schmidt KU, Dimopoulos S, Wenzel DA. Incidence of central retinal artery occlusion peaks in winter season. Front Neurol. 2024 Jan 22;15:1342491.
Changes in Neurodegeneration and Visual Prognosis in Branch Retinal Vein Occlusion after Resolution of Macular Edema
Long term macular edema following branch retinal vein occlusion (BRVO) can damage photoreceptors in the outer retina, thus leading to permanently decreased vision. This research sought to determine if the inner retina is also damaged in this situation, and if so, how that damage correlated to vision. BRVO patients seen at St. Mary’s Hospital in Seoul, South Korea, between January 2020 and January 2021, were retrospectively reviewed. Fellow eyes were used as the control, and exclusion criteria included pre-existing retinal disease or glaucoma, high myopia, and significant media opacity. A total of 57 eyes were included, and all of them had fully resolved macular edema. Of the 57 eyes, 40 had superior BRVO while the BRVO was inferior in 17 eyes. Swept-source ocular coherence tomography (OCT) was used to evaluate central macular thickness (CMT), ganglion cell thickness (GCL), and peripapillary retinal nerve fiber layer thickness (RNFL). These parameters were compared to their counterparts in the fellow eye and were also evaluated relative to final visual acuity. The peripapillary RNFL was significantly thinner in the temporal and nasal quadrants of BRVO eyes, as was the GCL in the affected quadrant. Thinning of the GCL in the nasal and middle areas was correlated with decreased final vision, likely due to this area representing the papillomacular bundle, while RNFL thickness and CMT were not. This research indicates that in addition to damaging the photoreceptors and external liming membrane in the outer retina, long term macular edema post BRVO appears to also damage the inner retina as well, with superior and nasal GCL thinning correlating to decreased vision. Final visual prognosis may depend, at least to some degree, on this inner retinal damage.
Park C, Lee JH, Park YG. Changes in Neurodegeneration and Visual Prognosis in Branch Retinal Vein Occlusion after Resolution of Macular Edema. J Clin Med. 2024 Jan 31;13(3):812.
Serum Vitamin D Level Alterations in Retinal Vascular Occlusions
The aim of this research was to evaluate serum vitamin D levels in ischemic versus non-ischemic retinal vascular occlusions. This study comprised of 50 patients with retinal vascular occlusions which included: central retinal vein occlusion, branch retinal vein occlusion, central retinal artery occlusion, and branch retinal artery occlusion along with a gender-matched healthy control group. The study concluded that there is a high prevalence of low serum vitamin D levels in patients with retinal vascular occlusions. It further concluded that ischemic types of retinal vascular occlusions have significantly lower serum vitamin D levels when compared to non- ischemic sub-types. However, the study had a low number of patients with arterial occlusions, making it impossible to generalize the findings of the study to all vascular occlusion types. The authors suggest that vitamin D supplementation may be considered a possible future targeted therapy in optimizing outcomes of retinal vascular disease. This study highlights the importance of evaluating serum vitamin D levels in all cases of RVO.
Bhanot R, Kumar A, Shankar S, et al. Serum vitamin D level alterations in retinal vascular occlusions. Photodiagnosis Photodyn Ther. 2024 Feb;45:103855.
Risk of Acute Stroke in Patients with Retinal Artery Occlusion: A Systematic Review and Meta-analysis.
This study is a systemic review and subsequent meta-analysis to evaluate the risk of acute stroke in patients with retinal artery occlusion (RAO). The analysis included 12 studies which comprised of 26,276,857 participants from 2004 to 2022. Out of these patients, 4,297 were affected by retinal artery occlusions.
Although the likelihood of stroke after retinal artery occlusion is well established, estimates of its occurrence are still disputed. One previous study estimates the stroke incidence for patients with acute retinal artery occlusion at 1%, while another clinical investigation reported the stroke incidence to be 37%. This analysis demonstrated that those with RAO have a noticeably higher chance of experiencing an acute stroke than people without RAO. Compared to people without RAO, patients with RAO, especially those under 75 years old, have a markedly increased risk of having an acute stroke following RAO. The author concluded that more investigation is needed to develop clinical management strategies for RAO that may include prompt referral to the emergency room or stroke unit for neurological assessment and brain imaging.
Al Jarallah O. Risk of acute stroke in patients with retinal artery occlusion: a systematic review and meta-analysis. Eur Rev Med Pharmacol Sci. 2023 Jun;27(12):5627-5635.