|Year : 2017 | Volume
| Issue : 10 | Page : 1023-1024
Vitreous opacities causing artifacts in optical coherence tomography angiography
Vinaya Kumar Konana, P Mahesh Shanmugam, Rajesh Ramanjulu, KC Divyansh Mishra
Department Vitreoretina and Ocular Oncology, Sankara Eye Hospital, Bengaluru, Karnataka, India
|Date of Submission||26-Jun-2017|
|Date of Acceptance||01-Aug-2017|
|Date of Web Publication||17-Oct-2017|
P Mahesh Shanmugam
Department of Vitreoretina and Ocular Oncology, Sankara Eye Hospital, Kundalahalli Gate, Varthur Main Road, Marathahalli, Bengaluru - 560 037, Karnataka
Source of Support: None, Conflict of Interest: None
Keywords: Artifacts, asteroid, ocular coherence tomography angiography, vitreous
|How to cite this article:|
Konana VK, Shanmugam P M, Ramanjulu R, Divyansh Mishra K C. Vitreous opacities causing artifacts in optical coherence tomography angiography. Indian J Ophthalmol 2017;65:1023-4
|How to cite this URL:|
Konana VK, Shanmugam P M, Ramanjulu R, Divyansh Mishra K C. Vitreous opacities causing artifacts in optical coherence tomography angiography. Indian J Ophthalmol [serial online] 2017 [cited 2020 Jan 21];65:1023-4. Available from: http://www.ijo.in/text.asp?2017/65/10/1023/216760
Ocular coherence tomography angiography (OCTA) is a noninvasive imaging modality to image chorioretinal vasculature. The quality of images acquired by OCTA can be compromised by artifacts. Various artifacts include projection, motion, blink and segmentation artifact. We aim to describe artifacts caused by vitreous opacities.
| Case Reports|| |
A 51-year-old diabetic visited us for diabetic retinopathy screening. Left eye fundus examination was limited due to asteroid hyalosis (AH) [Figure 1]a. Optical coherence tomography (OCT) of left eye demonstrated asteroid bodies with posterior vitreous detachment (PVD) [Figure 1]b. Left eye OCTA revealed multiple black areas in all slabs resembling capillary drop out areas [Fig. 1c-e]. The black dot is seen in [Figure 1]c is over the blood vessel which continues beyond that point, indicating that the vessel is patent.
|Figure 1: (a) Color fundus photo of left eye showing dense asteroid hyalosis obscuring the fundus view. (b) Ocular coherence tomography of left eye demonstrating asteroid bodies with posterior vitreous detachment. (c) Left eye Ocular coherence tomography angiography (superficial retinal slab) showing multiple black areas resembling capillary drop out areas. Yellow arrow shows that, the black area which can be confused with capillary drop out is over the blood vessel which, is seen to continue beyond that point indicating, that the vessel is patent. (d) shadow artifacts in deep retinal slab. (e) shadow artifacts in choriocapillary slab|
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A 46-year-old presented with floaters in the right eye. Fundus examination of the right eye was suggestive of branch retinal vein occlusion. An opening in the posterior hyaloid was noted superotemporal to the fovea [Figure 2]a. OCT of the right eye showed a PVD with an opening [Figure 2]b. OCTA showed an oval ring corresponding to opening in the posterior hyaloid in all slabs [Figure 2]c,[Figure 2]d,[Figure 2]e.
|Figure 2: Color photograph showing a ring like opening in the posterior hyaloid (white arrows) at the macula. (b) Ocular coherence tomography in the right eye showed posterior vitreous detachment. White arrows indicate opening in the posterior hyaloid. (c) right eye Ocular coherence tomography angiography at superficial retinal slab illustrating an oval shaped shadow corresponding to the location of the oval shaped opening in the posterior hyaloid. Areas of capillary drop out are seen superotemporal to the fovea with multiple microanuerysms. (d) Ring like artifact in deep retinal slab. (e) Ring like artifact in choriocapillary slab|
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| Discussion|| |
AH is a degenerative disorder of the vitreous. Smith reported that 27%–70% of patients with AH are diabetic. AH renders visualization of the microvascular abnormalities challenging. In such scenarios, fluorescein angiography (FA) helps us visualize retinal vasculature better. The barrier filter in fundus camera used to acquire FA absorbs the scattered blue light and allows only green light, making visualization possible. Meticulous evaluation of OCTA in eyes with vitreous opacity is crucial and shadows caused by vitreous opacities should be differentiated from capillary dropout.
| Conclusion|| |
Vitreous opacities such as AH and PVD can cause artifacts on OCTA. FA remains the investigation of choice in cases with AH.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Ghasemi Falavarjani K, Al-Sheikh M, Akil H, Sadda SR. Image artefacts in swept-source optical coherence tomography angiography. Br J Ophthalmol 2017;101:564-8.
Smith JL. Asteroid hyalitis and diabetes mellitus. Trans Am Acad Ophthalmol Otolaryngol 1965;69:269-78.
Delori F, Ben-Sira I, Trempe C. Fluorescein angiography with an optimized filter combination. Am J Ophthalmol 1976;82:559-66.
Hampton GR, Nelsen PT, Hay PB. Viewing through the asteroids. Ophthalmology 1981;88:669-72.
[Figure 1], [Figure 2]