Vogt-Koyanagi-Harada (VKH) disease is an autoimmune multisystem disorder directed against melanocytes. Acute ocular inflammation occurs as a bilateral granulomatous panuveitis characterized by bilateral diffuse choroiditis and prominent multifocal serous exudative retinal detachments. It is often associated with extraocular manifestations in the central nervous and integumentary systems. [4, 5]
As a new non-invasive diagnostic technique, OCT has become a method of choice to follow a number of macular diseases. Its reproducibility to measure retinal thickness in healthy subjects or in diabetic patients with macular edema has been demonstrated. OCT gives a high resolution of the images, with a longitudinal resolution of 10 microns.
Our case represents an unusual form of VKH in which the initial presentation was ocular i.e. sudden bilateral loss of vision with no other suggestive systemic symptoms or signs that can aid in the diagnosis. The visual acuity was so markedly reduced in the left eye more than the right which was parallel to a more increased retinal thickness in the left eye as shown by OCT images. A beneficial effect of corticosteroids was noticeable within days in the OCT images that were equivalent to the improvement in visual acuity for which treatment had been tapered slowly.
The (SD-OCT) of our patient showed significant changes in the retina during the acute stage involving multiloculated, cystic collections of serous fluid mixed with membranous structures under the sensory retina and the RPE, hyper-reflectance in outer retinal layers, intraretinal edema, subretinal septa, and no RPE folds had been noticed in contrary to what has been found by Kato Y et al who concluded that the detection of the folds of the RPE on OCT is a simple and effective method to help diagnose VKH disease at its acute stage which does not require pupil dilation. The OCT of the patient did not show also choroidal folds which appeared in the OCT of one patient reviewed by Shinoda K.
The tomographic features of serous retinal detachment (SRD) in eyes with VKH disease have been investigated in detail using OCT. Yamaguchi et al. detected a membrane on the RPE and subretinal septa (90% sensitivity for VKH) which disappeared immediately after treatment, and they assumed that the membrane was composed of inflammatory products such as fibrin.. Other OCT studies of eyes with VKH disease have shown an SRD during the acute and/or convalescence stages , and Yamanaka et al. showed a significant decrease in the height of the SRD immediately after the first and second intravenous corticosteroid injections. The same significant improvement in the retinal structure was seen in our patient after 2 days of oral, not intravenous corticosteroids. Yamamoto et al prove that SD-OCT is able to demonstrate characteristics of VKH that no other study to date has detected.
Ikewaki et al in their study mentioned that OCT parameters can be a reliable non-invasive real-time indicator of the severity of the inflammation and the effectiveness of the treatment in VKH and these parameters can be as important as the visual acuity. They also indicate that by using OCT, dynamic changes in the macular morphology reflecting the effect of the treatment can be monitored quantitatively and precisely and this may guide when the tapering of the dosage of steroids should begin and end. Regarding our patient, the decision to taper the treatment depended on the significant improvement in retinal structure seen in OCT as mentioned in this study.
Parc et al studied the OCT changes in the acute and chronic phases of VKH disease and demonstrated an atypical serous retinal detachment with the presence of intraretinal edema. The latter manifested as a hyporeflective area corresponding to liquid located between different layers of the neurosensory retina. They also notice retinal pigment epithelium (RPE) thickening corresponding to RPE hypertrophy and fibrosis. Nakai K et al concluded that significant choroidal thickness changes underlie VKH disease, which progresses over time, and their objective measurement (OCT) may be useful for longitudinal evaluation of VKH activity. Another finding by Theodoro da Silva F et al was that patients with VKH and long-standing disease had thinner choroids when compared to controls.