Efficacy of Multicolor Imaging in Patients With Asteroid Hyalosis: Seeing the Unseen

Multicolor imaging: Current clinical applications

Multicolor (MC) imaging is an innovative pseudocolor fundus imaging modality based on confocal scanning laser ophthalmoscopy. It effectively scans the retina at different depths to create a composite image. The green reflectance image depicts the middle retinal while blue reflectance image provides images of the retinal surface. The infrared reflectance image depicts retinal structures at the level of outer retina and choroid. We systematically analyze published case reports, case series, and original articles on MC imaging where it has helped in discovering additional clinical features of retinal diseases not readily apparent on conventional color fundus photography and played a role in monitoring the response to treatment.

Comparison of Multicolor Scanning Laser Imaging and Color Fundus Photography in Evaluating Vessel Whitening in Branch Retinal Vein Occlusion

INTRODUCTION

Few studies have explored MultiColor™ imaging (MCI) in evaluating retinal vascular diseases, particularly branch retinal vein occlusion (BRVO). This study aimed to compare the identification of retinal vessel whitening in BRVO using MCI by scanning confocal laser versus conventional white-flash color fundus photography (CFP).

METHODS

Paired images of consecutive patients diagnosed with BRVO who underwent same-day MCI and CFP were reviewed. Visualization of vessel whitening on MCI and CFP was graded and scored using a scale by two masked graders. A longitudinal analysis of the vessel grading score was performed to evaluate the vessel whitening detection by MCI. A correlation analysis was conducted between vessel whitening on MCI and the measured area of retinal ischemia on fluorescein angiography to evaluate the MCI performance.

RESULTS

Forty-four eyes of 41 patients (mean age 69 ± 14 years; 61% female) were analyzed. MCI demonstrated superior vessel whitening visibility score than CFP (p < 0.001). Longitudinal analysis showed no significant changes in vessel whitening visibility scores over a mean follow-up time of 430 ± 648 days (p = 0.655). There was a significantly positive correlation between the grading score of vessels whitening by MCI and the area of ischemia by fluorescein angiography (r2 = 0.15; p = 0.036).

CONCLUSION

MCI appears to provide a superior detection of whitening BRVO compared to CFP, serving as a rapid and non-invasive correlate of retinal ischemia.

Spotlight on Asteroid Hyalosis: A Clinical Perspective

Asteroid hyalosis is a benign degenerative condition of the vitreous that is often asymptomatic. Our purpose with this narrative review is to provide a current overview of asteroid hyalosis from a clinical perspective. We review the epidemiology and risk factors, the clinical diagnosis and differential diagnoses, clinical challenges in eyes with asteroid hyalosis, and the treatment of asteroid hyalosis. Many clinical questions remain unanswered, and the current evidence to guide clinical practice is largely based on anecdotal evidence and clinical experience. More studies on asteroid hyalosis from a clinical perspective are warranted.

Global prevalence of asteroid hyalosis and projection of its future burden: a systematic review and meta-analysis

Asteroid hyalosis is defined by the presence of white, snowball-like non-crystalline vitreous opacities that move with the vitreous and appear to be anchored to its matrix. Asteroid hyalosis commonly occurs in the absence of other identifiable ocular abnormalities and is usually an incidental finding. The vitreous opacities are usually invisible to the patient and asymptomatic, but asteroid hyalosis can be a significant obstacle to the examination of the fundus. The prevalence increases dramatically with age. The aetiology is unknown. We systematically reviewed the literature for epidemiological data, qualitatively reviewed available studies, conducted meta-analyses with demographical stratifications, evaluated temporal changes and estimated the future prevalence using forecasting analysis. Nine eligible studies were identified with data on 104 569 individuals. The overall population prevalence of asteroid hyalosis was 0.75% (95% confidence interval: 0.39-1.21%); however, the prevalence was highly age-dependent, ranging from 0.27% (95% confidence interval 0.12-0.49%) in individuals aged 0-39 years and gradually increasing to 3.07% (95% confidence interval 1.90-4.50%) in individuals aged ≥80 years. Male gender was an additional risk factor (odds ratio 1.80, 95% confidence interval 1.32-2.45, p = 0.00017). The estimated global prevalence was 10.7 million subjects in year 1950, which is expected to increase to 41.5 million in year 2020 and 91.2 million in year 2100. The prevalence of asteroid hyalosis is relevant because it impacts the utility of diagnostic strategies, especially screening methods for conditions such as diabetic retinopathy.

Asteroid hyalosis-a comprehensive review

Asteroid hyalosis is a relatively common cause of vitreous opacities, which is possibly associated with diabetes mellitus and hereditary pigmentary retinopathies. We review the history, epidemiology, and biochemistry of asteroid hyalosis, as well as its relationship with ocular and systemic conditions. We describe imaging modalities used for diagnostic evaluations in cases of severe asteroid hyalosis and propose hypotheses regarding its lack of significant effects on vision. We discuss cataract surgery in patients with asteroid hyalosis and the selection of intraocular lenses for implantation.

Measurement of size of pigmented choroidal nevus: Superiority of multicolor imaging compared to conventional color fundus photography

Choroidal nevi are benign fundus lesions that require regular follow with documentation. Conventional color fundus photography (CFP) has traditionally been used to images these lesions. Multicolor imaging (MCI) available on Spectralis spectral domain optical coherence tomography system is increasingly been tested vis-à-vis conventional CFP in various retinal diseases. We present data of the right eye of a 59-year-old gentleman with choroidal nevus who underwent conventional CFP as well as MCI. Nevus appeared orange red on MCI and its size appeared larger than the same measured on conventional CFP. We also report infrared reflectance and near infrared autofluorescence features of choroidal nevus.