Research progress of hyperreflective foci in OCT images in retinal and central nervous system diseases / 国际眼科杂志(Guoji Yanke Zazhi)

@#Microglial activation is one of the main pathogenic factors to cause retinal neuroinflammation. Recently, with the advancement of retinal imaging technologies, hyperreflective foci(HRF), as a novel biomarker in optical coherence tomography(OCT)imaging, have received more attention in retinal neuroinflammation. Current research demonstrated that HRF are the aggregates mainly derived from the activated microglia in retina or mononuclear phagocyte-macrophage from the blood. HRF were defined as discrete and well-circumscribed hyperreflective dot-shaped lesions with the maximum diameter between 20-50μm in retina and choroid imaged with OCT. Under pathological conditions, the number of HRF increases significantly. Under pathological condations, the number of HRF was obviously increased, which might be related to the severity of some retinal diseases. However, the research on the source and function of HRF is still in its infancy. This review is aimed to describe the basic characteristics of HRF and their roles in both retinal inflammatory diseases and neurodegenerative diseases of the central nervous system. HRF are expected to be a potential and novel biomarker of inflammation for early diagnosis and prognosis of neuroinflammation in both retinal and central nervous system diseases.

The status in the mechanism and significance of the hyperreflective foci in macular edema by optical coherence tomography / 中华眼底病杂志

Macular edema is an important cause of visual impairment in many eye diseases such as diabetic retinopathy, retinal vein occlusion and uveitis. Optical coherence tomography (OCT) provides high-resolution image of retinal microstructures in a non-contact and rapid manner, which greatly improves the ability of diagnosis and follow-up to macular edema patients. OCT has been widely used in the clinical detection of patients with macular edema. No matter what the cause of macular edema is, it can be observed in OCT images that there are spot-like deposits with strong reflection signals in the retina, which are mostly distributed discretely or partially convergent, and are called hyperreflective foci. At present, the nature or source of hyperreflective foci is not clear, however, may involve the destruction of the blood retina barrier, retinal inflammatory reaction, neurocellular degeneration, and so on. These mechanisms are also the key physiological mechanisms in the development of macular edema. The clinical research on hyperreflective foci provides a new direction for understanding the pathogenesis of macular edema and predicting the prognosis of macular edema. The distribution and quantity characteristics of hyperreflective foci may be an important biological marker to predict the prognosis of macular edema.nosis of macular edema. foci provides a new direction for understanding the pathogenesis of macular edema and predicting the prognosis of macular edema. The distribution and quantity characteristics of HRF may be an important biological marker to predict the prognosis of macular edema.

Comparision of Hyperreflective Foci after Treatment of Diabetic Macular Edema Patients between Intravitreal Injections

PURPOSE: To compare the outcomes in patients with diabetic macular edema (DME) treated with intravitreal dexamethasone implants and intravitreal bevacizumab injections.METHODS: A retrospective cohort study was designed using 66 patients with DME treated with intravitreal dexamethasone (n = 35; 35 eyes) and intravitreal bevacizumab (n = 31; 31 eyes). Post-treatment changes in hyperreflective foci in the inner and outer retina were characterized using optical coherence tomography, central macular thickness, outer limiting membrane, and photoreceptor inner segment-outer segment junctions. Visual acuities were analyzed 4 weeks after bevacizumab injections and 8 weeks after dexamethasone injections.RESULTS: Both groups showed a decrease in the number of hyperreflective foci after treatment: from 10.6 ± 11.8 to 6.3 ± 5.9 (p = 0.005) in the intravitreal dexamethasone implant group and from 11.6 ± 8.5 to 7.7 ± 6.7 (p < 0.001) in the intravitreal bevacizumab injection group. The mean central macular thickness in the dexamethasone group changed significantly from 586.8 µm to 297.7 µm after treatment and the visual acuity improved significantly from 0.33 logMAR to 0.38 logMAR after treatment (p < 0.001 and p = 0.018, respectively). The mean central macular thickness in the bevacizumab group showed a significant decrease from 467.1 µm to 353.2 µm after treatment (p < 0.001), but there was no significant change in the visual acuities: 0.34 logMAR to 0.32 logMAR after treatment (p = 0.464).CONCLUSIONS: Both intravitreal dexamethasone implants and bevacizumab treatments in patients with DME showed improved outcomes including a decrease in hyperreflective foci shown by optical coherence tomography.

Factors Related to Refractory Macular Edema in Branch Retinal Vein Occlusion

PURPOSE: To evaluate the factors associated with refractory macular edema (ME) secondary to branch retinal vein occlusion (BRVO) after three times of intravitreal bevacizumab (IVB) injections. METHODS: Ninety eyes of Ninety patients, who were retrospectively reviewed, were treated with IVB of 1.25 mg (0.05 mL) for ME secondary to BRVO, repeated three times at 4-week intervals and then followed-up for at least 4 months after the IVB. The patients were classified as refractory if there was an increase in the mean retinal thickness >150 µm when measured 1 month after the three injections. The patients were divided into two groups: a responsive group (46 eyes) and a refractory group (44 eyes). RESULTS: In univariate logistic regression analyses, age, diabetes mellitus, hypertension, visual acuity, maximal combined response b wave amplitude (Max B amp), maximal combined response B/A ratio (Max B/A), cone response b wave amplitude, subfoveal choroidal thickness (SFCT), and the number of hyperreflective foci (HF) were risk factors for refractory ME of BRVO (p = 0.045, p = 0.010, p = 0.037, p = 0.034, p = 0.003, p = 0.004, p = 0.001, p = 0.001 and p = 0.001, respectively). In backward multivariate logistic regression analyses, age, Max B amp, Max B/A, SFCT and number of HF were risk factors for refractory ME of BRVO (p = 0.024, p = 0.004, p = 0.047, p = 0.033 and p = 0.049, respectively). CONCLUSIONS: Baseline age, Max B amp, Max B/A, SFCT and number of HF predicted the probability of refractory ME secondary to BRVO after IVB.

Correlation between Visual Outcomes and Pre-Treatment Factors Including Hyperreflective Foci in Neovascular Age-Related Macular Degeneration

PURPOSE: To investigate the correlation between hyperreflective foci (HF) on spectral domain optical coherence tomography (SD-OCT) at baseline and visual outcomes after intravitreal ranibizumab injection in neovascular age-related macular degeneration (nAMD). METHODS: We retrospectively reviewed the medical records of 44 eyes of 44 nAMD patients. The number of HF was counted according to the location of HF on SD-OCT: neurosensory retinal layer, outer retinal layer, and subretinal layer. Statistical correlations among final visual acuity (VA) and pretreatment OCT parameters including number of HF, foveal thickness (FT), thickness of choroidal neovascularization (CNV), the status of external limiting membrane, and photoreceptor inner and outer segments (IS/OS) were evaluated. RESULTS: The number of HF was reduced in all retinal layers in nAMD patients after treatment. In multivariate regression analysis, final VA was associated with baseline VA, number of subretinal HF, and IS/OS disruption length (p = 0.028, p = 0.046 and p = 0.009, respectively) in nAMD patients. The baseline number of subretinal HF was correlated with final FT and CNV thickness (p = 0.002 and p = 0.009, respectively). CONCLUSIONS: The baseline number of subretinal HF on SD-OCT might predict the final VA after intravitreal ranibizumab treatment in nAMD patients.