Findings of Optical Coherence Tomography Angiography in Best Vitelliform Macular Dystrophy

Optical Coherence Tomography in Inherited Macular Dystrophies: A Review

Macular dystrophies (MDs) constitute a collection of hereditary retina disorders leading to notable visual impairment, primarily due to progressive macular atrophy. These conditions are distinguished by bilateral and relatively symmetrical abnormalities in the macula that significantly impair central visual function. Recent strides in fundus imaging, especially optical coherence tomography (OCT), have enhanced our comprehension and diagnostic capabilities for MD. OCT enables the identification of neurosensory retinal disorganization patterns and the extent of damage to retinal pigment epithelium (RPE) and photoreceptor cells in the dystrophies before visible macular pathology appears on fundus examinations. It not only helps us in diagnostic retinal and choroidal pathologies but also guides us in monitoring the progression of, staging of, and response to treatment. In this review, we summarize the key findings on OCT in some of the most common MD.

Multimodal imaging in Best Vitelliform Macular Dystrophy: Literature review and novel insights

Best Vitelliform Macular Dystrophy (BVMD) is a dominantly inherited retinal disease caused by dominant variants in the BEST1 gene. The original classification of BVMD is based on biomicroscopy and color fundus photography (CFP); however, advancements in retinal imaging provided unique structural, vascular, and functional data and novel insights on disease pathogenesis. Quantitative fundus autofluorescence studies informed us that lipofuscin accumulation, the hallmark of BVMD, is unlikely to be a primary effect of the genetic defect. It could be due to a lack of apposition between photoreceptors and retinal pigment epithelium in the macula with subsequent accumulation of shed outer segments over time. Optical Coherence Tomography (OCT) and adaptive optics imaging revealed that vitelliform lesions are characterized by progressive changes in the cone mosaic corresponding to a thinning of the outer nuclear layer and then disruption of the ellipsoid zone, which are associated with a decreased sensitivity and visual acuity. Therefore, an OCT staging system based on lesion composition, thus reflecting disease evolution, has been recently developed. Lastly, the emerging role of OCT Angiography proved a greater prevalence of macular neovascularization, the majority of which are non-exudative and develop in late disease stages. In conclusion, effective diagnosis, staging, and clinical management of BVMD will likely require a deep understanding of the multimodal imaging features of this disease.

Evaluation of retina and choroid perfusion with optical coherence tomography angiography in patients with retinitis pigmentosa

PURPOSE

In this study, we aimed to evaluate macular perfusion with optical coherence tomography angiography (OCTA) and to investigate the correlation between OCTA quantitative data and visual acuity (VA) in patients with retinitis pigmentosa (RP).

METHODS

This retrospective single-center study was conducted on 60 eyes of 30 RP patients and 52 healthy eyes. The vessel density (VD) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) of the macula, the size of foveal avascular zone (FAZ), choriocapillary flow density (FD) were measured using OCTA. Quantitative data obtained with OCTA were compared between the two groups. In addition, the correlation between the OCTA measurements and VA was examined.

RESULTS

In patients with RP, the choriocapillary FD was decreased (p = 0.001), the FAZ area was enlarged (p = 0.010), and the VDs of the SCP and DCP were decreased in all areas (p = 0.001). Correlation was found between VA and SCP VD, whole image (p = 0.011, rho = -0.327) and parafoveal (p = 0.001, rho = -0.444) areas.

CONCLUSION

Quantitative data from OCTA showed reduced macular perfusion in patients with RP compared to healthy controls. There was also a correlation between the quantitative OCTA data and VA.

Clinical Applications of Optical Coherence Tomography Angiography in Inherited Retinal Diseases: An Up-to-Date Review of the Literature

Optical coherence tomography angiography (OCT-A) is a valuable imaging technique, allowing non-invasive, depth-resolved, motion-contrast, high-resolution images of both retinal and choroidal vascular networks. The imaging capabilities of OCT-A have enhanced our understanding of the retinal and choroidal alterations that occur in inherited retinal diseases (IRDs), a group of clinically and genetically heterogeneous disorders that may be complicated by several vascular conditions requiring a prompt diagnosis. In this review, we aimed to comprehensively summarize all clinical applications of OCT-A in the diagnosis and management of IRDs, highlighting significant vascular findings on retinitis pigmentosa, Stargardt disease, choroideremia, Best disease and other less common forms of retinal dystrophies. All advantages and limitations of this novel imaging modality will be also discussed.

Clinical Correlation Between Optical Coherence Tomography Biomarkers and Retinal Sensitivity in Best Vitelliform Macular Dystrophy

Purpose

To investigate the clinical and imaging features associated with retinal sensitivity in Best vitelliform macular dystrophy (BVMD).

Methods

This was a cross-sectional, single-center, observational study. Each patient underwent optical coherence tomography (OCT), near-infrared fundus autofluorescence, and OCT angiography. Macular integrity assessment microperimetry under mesopic conditions was performed to obtain retinal sensitivity thresholds from 68 testing points in the central macula. Structural OCT was used to classify BVMD lesions into four types according to their composition: vitelliform, mixed, subretinal fluid, and atrophy. Multilevel, mixed-effects linear regression was used to determine the factors associated with retinal sensitivity.

Results

The study included 57 eyes of 30 patients with BVMD, 48 of which (84%) were in a clinical stage. Mean retinal sensitivity varied according to the composition of the lesion: the vitelliform type registering the highest (22 ± 4.1 dB), followed by mixed (18.73 ± 2.7 dB), subretinal fluid (15.68 ± 4.2 dB), and atrophy types (11.85 ± 4.6 dB). The factors most strongly associated with mean retinal sensitivity in BVMD proved to be the OCT lesion type and outer nuclear layer thickness.

Conclusions

Retinal sensitivity in BVMD is influenced by lesion composition and outer nuclear layer thickness. Further studies with long-term follow-up are warranted to examine retinal sensitivity over time and to validate retinal sensitivity changes as biomarkers for BVMD.

Translational Relevance

Assessing retinal sensitivity in BVMD provides a new instrument in the clinical characterization of the disease and offers the opportunity to identify imaging biomarkers for use as outcome measures in future clinical trials.

Optical Coherence Tomography Angiography in Patients with Cone Dystrophy

PURPOSE

This study aimed to evaluate macular perfusion using optical coherence tomography angiography (OCTA) in patients with cone dystrophy and to determine the associations between the quantitative data of OCTA and functional parameters.

METHODS

The data of 36 eyes of 18 patients with cone dystrophy and 38 eyes of 19 healthy controls were analyzed. The superficial and deep capillary plexus (SCP and DCP) vessel densities (VD) of the macula, the foveal avascular zone (FAZ) and choriocapillary flow density values were obtained using OCTA. The associations between visual acuity (VA) and full-field electroretinography (ffERG) and the quantitative data of OCTA, and the associations between OCTA and ffERG were analyzed.

RESULTS

: VD was significantly lower in all areas except the foveal area in SCP in the cone dystrophy group compared to the control group. VA was found to be associated with the VDs of the SCP and DCP except for that of the foveal SCP. VA was also associated with dark-adapted, light-adapted wave amplitudes.

CONCLUSION

OCTA quantitatively showed that macular perfusion was decreased in cone dystrophy compared to the healthy controls. In addition, there was an association between VA and ffERG parameters and quantitative data of OCTA.

The Role of Optical Coherence Tomography Angiography (OCTA) in Detecting Choroidal Neovascularization in Different Stages of Best Macular Dystrophy: A Case Series

Best macular dystrophy (BMD) is an autosomal dominant macular dystrophy of childhood onset characterized by bilateral and symmetric vitelliform lesions. Several stages of disease have been well-described in the literature. Choroidal neovascularization (CNV) has traditionally been considered a hallmark of end-stage disease, and anti-vascular endothelial growth factor (anti-VEGF) agents have been used to improve visual prognosis. While CNV was historically detected with fluorescein angiography, optical coherence tomography angiography (OCTA) has recently been employed as a novel mechanism for identifying CNV in BMD. In this case series, we discuss our institutional experience with using OCTA to detect CNV in BMD and contextualize this experience within the broader emerging literature. While OCTA allows for the identification of CNV in less severe stages of BMD, the management of this CNV remains uncertain.

Optical Coherence Tomography Angiography Imaging in Inherited Retinal Diseases

Optical coherence tomography angiography (OCTA) is a novel, noninvasive imaging modality that allows depth-resolved imaging of the microvasculature in the retina and the choroid. It is a powerful research tool to study the pathobiology of retinal diseases, including inherited retinal dystrophies. In this review, we provide an overview of the evolution of OCTA technology, compare the specifications of various OCTA devices, and summarize key findings from published OCTA studies in inherited retinal dystrophies including retinitis pigmentosa, Stargardt disease, Best vitelliform macular dystrophy, and choroideremia. OCTA imaging has provided new data on characteristics of these conditions and has contributed to a deeper understanding of inherited retinal disease.

Altered ellipsoid zone reflectivity and deep capillary plexus rarefaction correlate with progression in Best disease

AIMS

To evaluate the effects of neurovascular damage in patients with the typical vitelliform lesion of Best vitelliform macular dystrophy (BVMD) in the attempt to identify different progression patterns.

METHODS

Prospective, observational case series. Patients in the vitelliform stage of BVMD and healthy controls underwent complete ophthalmological examination on a yearly basis, including best-corrected visual acuity (BCVA), biomicroscopy, optical coherence tomography (OCT) and OCT angiography (OCT-A). 4.5×4.5 mm OCT-A slabs were imported into ImageJ software and their vessel density (VD) was calculated. Similarly, the ellipsoid zone (EZ) was manually outlined and the reflectivity was measured above the vitelliform lesion and in the 500 µm external to it. Retinal pigment epithelium-Bruch's membrane complex was taken as internal reference.

RESULTS

34 eyes (24 patients) and 34 matched controls were included in the study. Mean follow-up was of 28.4±5.8 months, with 12 eyes showing signs of stage progression at the end follow-up. The EZ overlying the vitelliform lesion and in the peri-lesional area disclosed a significant reduction in reflectivity when compared with the foveal and para-foveal EZ of controls, respectively. VD resulted meaningfully decreased only at the deep capillary plexus. Of notice, more extensive EZ (reflectivity <0.7) and vascular alterations (VD <0.4) at baseline strongly correlated with worse BCVA and were associated with a more rapid progression at follow-up.

CONCLUSIONS

Both EZ reflectivity and VD at deep capillary plexus may prove valuable biomarkers to assess BVMD severity and detect progression. In this view, 'rapid progressors' might benefit the most from timely genetic therapies in the future.

Multimodal imaging including optical coherence tomography angiography in patients with type B Niemann-Pick disease

PURPOSE

To evaluate accumulation patterns of deposits in retinal layers of type B Niemann-Pick patients by multimodal imaging.

METHODS

Seven patients with type B Niemann-Pick disease were included in this study. All participants underwent a complete ophthalmologic evaluation, high-resolution digital colour imaging, spectral-domain optical coherence tomography, blue light fundus autofluorescence and optical coherence tomography angiography (OCTA).

RESULTS

We demonstrated different accumulation patterns in the retinal ganglion cell layer, the retinal nerve fibre layer and the subfoveolar region by multimodal imaging. Local retinal capillary nonflow areas in the superficial plexus, increased vascular tortuosity and deformed foveal avascular areas were shown in OCTA scans.

CONCLUSION

Multimodal imaging including OCTA is a useful technique for the identification of different types of accumulation patterns, diagnosis and follow-up of type B Niemann-Pick patients.