|Year : 2019 | Volume
| Issue : 4 | Page : 267-270
Photoreceptor stretching: An optical coherence tomography finding in a case of incomplete Vogt–Koyanagi–Harada disease
Carlos Mario Pinilla-Gomez, Francisco José Rodríguez-Alvira
National Ophthalmology Foundation; Medicine and Health Sciences Faculty, University of the Rosary, Bogotá, Colombia
|Date of Submission||23-Aug-2019|
|Date of Acceptance||11-Oct-2019|
|Date of Web Publication||13-Dec-2019|
Dr. Francisco José Rodríguez-Alvira
Calle 50 # 13 – 50, Cundinamarca, Bogotá 110231
Source of Support: None, Conflict of Interest: None
The aim of the study was to describe an optical coherence tomography finding in Vogt–Koyanagi–Harada (VKH) disease and discuss its physiopathology. A 34-year-old Hispanic male was referred to the retina clinic, with 2 weeks of “drowsiness,” headache, photopsia, and blurred vision. He was diagnosed with incomplete VKH. Optical coherence tomography, among other studies, was obtained, and a focal separation of the photoreceptor outer segments (OSs) from the inner neuroepithelium was observed. Here, we report a rare finding associated with VKH disease, which we called photoreceptor stretching and hypothesize it results from the presence of a spot of strong adherence between the OS of the photoreceptors and the retinal pigment epithelium.
Keywords: Fluorescein angiography, optical coherence tomography angiography and photoreceptor, optical coherence tomography, Vogt–Koyanagi–Harada disease
|How to cite this article:|
Pinilla-Gomez CM, Rodríguez-Alvira FJ. Photoreceptor stretching: An optical coherence tomography finding in a case of incomplete Vogt–Koyanagi–Harada disease. Taiwan J Ophthalmol 2019;9:267-70
|How to cite this URL:|
Pinilla-Gomez CM, Rodríguez-Alvira FJ. Photoreceptor stretching: An optical coherence tomography finding in a case of incomplete Vogt–Koyanagi–Harada disease. Taiwan J Ophthalmol [serial online] 2019 [cited 2020 Jan 26];9:267-70. Available from: http://www.e-tjo.org/text.asp?2019/9/4/267/272256
| Introduction|| |
Vogt–Koyanagi–Harada (VKH) disease is a systemic autoimmune disorder, mainly affecting pigmented tissues in the ocular, integumentary, auditory, and central nervous systems. VKH disease affects mainly darkly pigmented races, such as East and Southeastern Asian, Hispanic, and Native Americans, typically presents in the ages between 20 and 50 years. VKH is clinically divided into four stages: prodromal, acute, convalescent, and chronic recurrent., During the acute phase, ocular involvement is characterized by severe bilateral granulomatous panuveitis involving the choroid and is associated with multifocal serous retinal detachments.,
The diagnosis of VKH is usually based on clinical examination combined with optical coherence tomography (OCT), fluorescein angiography (FA), and indocyanine green angiography. Reports on the imaging features of the disease have helped understanding the physiopathology of the disease due to the lack of pathology specimens or animal models.,
OCT provides noninvasive, high-speed, high-resolution, three-dimensional images of the human macula. OCT findings in VKH include macular edema (seen as increased retinal thickness or intraretinal cysts), subretinal fluid, subretinal septa, retinal pigment epithelium (RPE) distortion, and pigment epithelial detachment.
Here, we report a case of a young otherwise healthy male, diagnosed with incomplete VKH disease, who presented with a separation of the photoreceptor outer segments (OSs) from the inner retina and proposed a physiopathogical theory.
| Case Report|| |
A 34-year-old Hispanic male was referred to the retina clinic for 2 weeks of what he described as “drowsiness,” mild headache, photopsia, and blurred vision; symptoms initially affected his right eye but 48 h later became bilateral. Best-corrected visual acuity was 20/25 in both the eyes, external examination and biomicroscopy were unremarkable, and intraocular pressure was slightly elevated in both the eyes.
Fundus examination of the right eye revealed multiple coalescent elevated gray lesions involving the macula, extending beyond the inferior temporal vascular arcade. The left fundus presented a similarly isolated lesion located in the mid periphery temporally [Figure 1].
|Figure 1: Right and left eye red-free photograph and fluorescein angiography. Multiple hyperfluorescent spots with extensive leakage and pooling of the dye involving the entire macula in the right eye and focally localized in the left eye|
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Fundus autofluorescence showed these lesions as multiple hyperautofluorescent spots surrounded by a slightly hyperautofluorescent halo, which made related structures look blurry. On FA, these lesions appeared as multiple hyperfluorescent spots with extensive leakage and pooling of the dye involving the entire macula in the right eye and focally localized in the left eye [Figure 1].
OCT presented with the undulation of the inner retinal surface, extensive subretinal fluid, irregularities of the RPE, and a small dome-shaped separation of the outer layers of the retina below the external limiting membrane, located slightly inferior to the center of the fovea in the right eye. This finding was confirmed in multiple slides [Figure 2]. The left eye also showed subretinal fluid, RPE irregularities, and inner retinal surface undulation, but no separation of the outer layers of the neurosensory retina was detected.
|Figure 2: Optical coherence tomography of the right eye macula, showing undulation of the inner retinal surface, extensive subretinal fluid, irregularities of the retinal pigment epithelium, and a small, dome-shaped separation of the outer layers of the retina below the external limiting membrane, located slightly inferior to the center of the fovea in the right eye|
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OCT-angiography was also performed, subtle irregularity of the foveal avascular zone edges at the deep retinal plexus was observed in both the eyes, and small areas of flow void were detected at the choriocapillaris.
Based on these findings, an incomplete VKH disease diagnosis was made, and the patient was started on a 1 mg/kg prednisolone course; a fixed combination of topical dorzolamide, brimonidine, and timolol TID was referred for the neurology consultation. One week later, subretinal fluid had notably diminished, and the OSs had reattached to the inner retinal layers. Three weeks later, subretinal fluid had completely disappeared, and a 20/20 visual acuity was regained bilaterally [Figure 3].
|Figure 3: Optical coherence tomography showing the absence of subretinal fluid|
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| Discussion|| |
Here, we report a case of incomplete VKH disease who presented with a rare tomographic finding; to the best of our knowledge, the first time to be described in the literature.
The patient was diagnosed with an incomplete acute VKH disease. He presented with multiple bilateral serous retinal detachments, subtle neurological symptoms, and no auditory symptoms. Central serous chorioretinopathy (CSC) is the main differential diagnosis. However, CSC is usually unilateral, does not improve with steroid therapy, and lacks neurological symptoms.
OCT has shown to be useful for the diagnosis and follow-up of VKH, being a reliable tool for the detection and measurement of subretinal fluid and choroidal thickness. Our patient had extensive subretinal fluid in both the eyes and RPE irregularity, typical findings of VKH disease. No pigmented epithelium detachments were found, although they can be found in VKH which are more typical of CSC.,, In 2014, Lin et al. described internal limiting membrane (ILM) fluctuations as a finding in VKH disease; we found smooth wave-shaped undulations of the ILM related to pockets of subretinal fluid. This finding seems to represent uneven diffuse edema of the retina, making the retina bulge inside at some points.
No subretinal septa were observed, but Lin et al. found them to be present in 84.6% of their patients and considered those septa to be a part of the photoreceptor OSs that separated from the inner retina.
The presence of multiple areas of flow void in the choriocapillaris has been described on OCT-angiography; these areas decrease in size until disappearance, when adequate control of the disease is achieved. This makes OCT-angiography a promising tool for VKH disease follow-up.,,
We propose that the separation of the photoreceptor OSs from the inner retinal layers represents longitudinal stretching of the cones and rods. Photoreceptor stretching can be caused by foci of strong photoreceptor-to-RPE adherence (Image 2 bottom), favoring the elongation of photoreceptors at the inner and OS junction, when a serous retinal detachment is taking place. A similar theory was proposed by Liakopoulos et al. in patients with neovascular age-related macular degeneration and subretinal hemorrhage.
They named it “presumed photoreceptor delamination,” considering it to be a separation of the OSs from the rest of the photoreceptor's body and concluded that the strong adhesion resulted from the presence of blood in the subretinal space, which is not the case in VKH.
Ishihara et al. reported a series of 10 patients (20 eyes) with VKH disease diagnosis and concluded that the membranous structure seen in eyes with acute VKH disease represents a portion of the OS layer that has become separated from the inner segment layer by cystoid spaces. In their patients, the OSs of the photoreceptors end up separating from the inner retina and remain attached to the RPE due to the presence of fibrin which acts as glue; the separated OSs collapse on the RPE appearing as a granular structure instead of membranous. They also noticed that the IS/OS layer was still present in the detached retina bridging the membranous structure in 55% of their patients, and 45% of patients presented the splitting above the IS/OS layer, which may correspond to two different etiologies. When compared to ours, Ishihara et al. lesions show a broader shape, different from the pointed shape seen in our patient, which we interpreted as a sign of traction. Besides, no intraretinal fluid was present, as seen by Ishihara et al. Although they may correspond to different stages of the same process, we believe they differ in physiopathology.
The shape of the photoreceptor separation encountered in our patient is, to our knowledge, the first to be reported in the literature. We consider that the kind of photoreceptor distortion seen in VKH is due to focal traction resulting from the presence of spots of stronger adherence between the OSs of the photoreceptors and the RPE, favored by the glue effect of fibrin described by Ishihara et al. Different from what Ishihara et al. observed, in our patient, the OSs seem to return to their original configuration, and good visual acuity is regained.
Based on these findings, stretching of photoreceptors could be interpreted as a biomarker of good visual prognosis due to the fact that photoreceptors returned to their original disposition and good visual acuity was recovered. A larger number of patients need to be followed to confirm this association.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent. The patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
The authors declare that there are no conflicts of interests of this paper.
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[Figure 1], [Figure 2], [Figure 3]