Multicolor Imaging Characteristics of Best's Vitelliform Macular Dystrophy.

A 40-year-old woman presented with vitellieruptive stage of Best's vitelliform macular dystrophy (BVMD) in the right eye and pseudohypopyon stage in the left eye. She underwent comprehensive ophthalmic examination and fundus imaging using multicolor (MC) imaging technology of Spectralis (Heidelberg Engineering, Heidelberg, Germany) spectral-domain-optical coherence tomography system. Composite MC imaging revealed larger area of retinal pigment epithelium atrophy in vitellierruptive stage of the disease in the right eye compared to color fundus photograph. Retinal elevation in the pseudohypopyon stage was better delineated on composite MC and blue reflectance images in the left eye. Subretinal lipofuscin was best seen in green reflectance and short-wave autofluorescence images. The present case reports the MC imaging features of BVMD. Copyright:

Introduction

Multicolor (MC) imaging technology is a novel noninvasive retinal imaging modality. It acquires three reflectance images of the retina using blue, green, and infrared lasers with a confocal scanning laser ophthalmoscope to produce a composite image.[1] MC provides information about structural changes right from the vitreomacular interface to the retinal pigment epithelium (RPE). It provides better delineation of the epiretinal membrane compared to conventional fundus photograph.[2] MC shows high accuracy in the measurement of geographic atrophy in age-related macular degeneration.[3] We herein report the MC imaging characteristics of Best vitelliform macular dystrophy (BVMD).

Case Report

A 40-year-old woman presented with the complaint of gradual dimness of vision in her both eyes. Best-corrected visual acuity in her right and left eyes was 20/120, N10 and 20/40, N10 respectively. Anterior segment was unremarkable in both eyes.

Fundus examination in the right eye revealed RPE atrophy with tiny speckle-like yellowish deposits near the fovea [Figure 1a]. Composite MC image of the right eye showed an area of mottled RPE hyperpigmentation which was larger than the area of RPE abnormality seen on color fundus photograph (FP) [Figure 1b]. It also showed yellowish deposits as seen on color FP. Fundus examination of the left eye revealed a circular area of retinal elevation centered at the fovea, with layering of a yellowish material at the lower end along with scattered yellowish deposits [Figure 2a]. Composite MC image of the left eye showed a well-delineated area of retinal elevation with a blue-green hue to the elevated retina [Figure 2b]. It also showed scattered yellowish deposits as seen on color FP along with RPE hyperpigmentation at the center of the fovea. A diagnosis of BVMD was made, and electro-oculogram was performed which revealed reduced Arden's ratio in both eyes (right eye 1.23 and left eye 1.40). The right eye was in vitellieruptive stage and the left eye in pseudohypopyon stage.

Figure 1

(a) Color fundus photograph of the right eye shows retinal pigment epithelium alterations at the center of the macula along with subretinal yellowish deposits (white arrow) suggestive of vitellieruptive stage of Best's vitelliform macular dystrophy. The area of retinal pigment epithelium mottling temporal to fovea (white solid arrow) is barely seen. (b) Composite multicolor image of the right eye shows a larger area of retinal pigment epithelium mottling (white arrows) compared to color fundus photograph. It shows retinal pigment epithelium mottling temporal to fovea (white solid arrow) better than color fundus photograph

Figure 2

(a) Color fundus photograph of the left eye shows area of retinal elevation at the center of the macula with yellowish subretinal deposit at the dependent part (solid white arrow) suggestive of lipofuscin. (b) Composite multicolor image of the left eye gives blue-green hue to the elevated retina and delineates the margin of elevation sharply (white arrows). Subretinal yellowish lipofuscin deposits (solid star) are brighter than composite fundus photograph

Further, component MC images were analyzed separately. Blue reflectance image of the left eye showed a well-demarcated area of retinal elevation centered at the macula along with bright layered deposits at the inferior part suggestive of subretinal deposits [Figure 3a]. The layered deposits appeared brighter in green reflectance image, which also showed speckle-like spots within the retinal elevation [Figure 3b]. These bright layered deposits and speckle-like spots were lipofuscin deposits in the subretinal space. Infrared reflectance image showed a ring corresponding to the elevated retina along with mottling RPE [Figure 3c]. The subretinal lipofuscin deposit appeared brightest on short-wave autofluorescence which also showed a ring corresponding to the elevated retina [Figure 3d]. Spectral-domain-optical coherence tomography (SD-OCT) line scan across the macula using Spectralis HRA + OCT (Heidelberg Engineering, Heidelberg, Germany) showed loss of external limiting membrane and an ellipsoid zone along with hyperreflective subretinal deposits [Figure 4a]. The left eye showed empty space beneath the center of the macula with overlying thinning of the outer nuclear layer [Figure 4b].

Figure 3

(a) Blue reflectance image of the left eye shows well-circumscribed ring of retinal elevation (white arrow) with subretinal lipofuscin. (b) Subretinal lipofuscin layered inferiorly (solid arrow) and scattered through the retinal elevation (white arrow) appeared brighter on green reflectance image. (c) Infrared reflectance image of the left eye shows retinal pigment epithelium mottling within the area of retinal elevation. (d) Short-wave autofluorescence shows the subretinal lipofuscin deposits as bright white spots (solid arrow)

Figure 4

(a) Spectral-domain-optical coherence tomography line scan through the macula in the right eye shows zone of disruption of external limiting membrane and ellipsoid zone at the macula delineated with white solid arrows, along with the underlying hyperreflective deposits. (b) Spectral-domain-optical coherence tomography line scan through the macula in the left eye shows thinning of the outer nuclear layer (white arrows) and empty space (white star) owing to pseudohypopyon stage

The patient was explained about the eye condition and was prescribed suitable low-vision aids. Need of regular checkup was explained to her.

Discussion

MC technology uses monochromatic laser lights of blue, green, and infrared range to produce a composite image of the retina.[1] While blue reflectance is mainly concerned with vitreoretinal interface and inner retinal layer, green reflectance images deeper retinal layers. Infrared reflectance images provide information about RPE and choroid. MC has been used for imaging various retinal disorders involving vitreoretinal interface, retina, optic nerve, and choroid.[234] Blue reflectance image was noted to be superior to color FP for imaging dissociated optic nerve fiber layer after internal limiting membrane peeling for macular hole.[5] Yu et al.[4] have reported infrared reflectance to be suited the most for imaging reticular pseudodrusen.

We report that composite MC showed a greater extent of RPE abnormalities in the vitellieruptive stage of BVMD. It was superior to color FP in showing retinal elevation in pseudohypopyon stage. While retinal elevation was best seen in blue reflectance image, it was inferior to green reflectance image in showing subretinal lipofuscin deposits which appeared more prominent later. Short-wave autofluorescence showed subretinal lipofuscin more vividly than blue, green, or infrared reflectance owing to the autofluorescent property of lipofuscin. Infrared reflectance image showed a larger area of RPE abnormality than that seen on blue or green reflectance, which may probably be due to its use in prognostication.

Multimodal imaging characteristics of BVMD and adult-onset vitelliform macular dystrophy have been reported in past using SD-OCT, infrared imaging, and autofluorescence imaging.[678] However, MC imaging characteristics of BVMD are hitherto unreported. Study of MC imaging characteristics in a larger case series may further substantiate our findings. By the virtue of depicting RPE abnormalities better, infrared reflectance may be of prognostic value.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.