Ophthalmic Surgery, Lasers and Imaging Retina

Case Report 

Swept-Source Optical Coherence Tomography Angiography Findings in Torpedo Maculopathy

Zaria Ali, MBChB; Carol Lally Shields, MD; Kirti Jasani, FRCOphth; Tariq Mehmood Aslam, PhD; Konstantinos Balaskas, MD

Abstract

Torpedo maculopathy is a rare congenital anomaly of the retinal pigment epithelium (RPE). Various imaging modalities have been used to assess cases of torpedo maculopathy, including optical coherence tomography (OCT) and fundus autofluorescence (FAF). OCT angiography (OCTA) offers combined structural and flow characteristics of imaged lesions. The authors present OCTA findings in two cases of torpedo maculopathy. Common features include loss of RPE and choriocapillaris allowing greater visualization of larger vessels in the outer choroid. This confirms the potential of OCTA to provide greater detail of retinal and choroidal architecture and elucidate the histopathology of retino-choridal lesions.

[Ophthalmic Surg Lasers Imaging Retina. 2017;48:932–935.]

Abstract

Torpedo maculopathy is a rare congenital anomaly of the retinal pigment epithelium (RPE). Various imaging modalities have been used to assess cases of torpedo maculopathy, including optical coherence tomography (OCT) and fundus autofluorescence (FAF). OCT angiography (OCTA) offers combined structural and flow characteristics of imaged lesions. The authors present OCTA findings in two cases of torpedo maculopathy. Common features include loss of RPE and choriocapillaris allowing greater visualization of larger vessels in the outer choroid. This confirms the potential of OCTA to provide greater detail of retinal and choroidal architecture and elucidate the histopathology of retino-choridal lesions.

[Ophthalmic Surg Lasers Imaging Retina. 2017;48:932–935.]

Introduction

Torpedo maculopathy is a rare entity and is thought to be a congenital anomaly of the retinal pigment epithelium (RPE).1 Various imaging modalities have been used to assess cases of torpedo maculopathy, including optical coherence tomography (OCT) and fundus autofluorescence (FAF). We describe features detected on OCT angiography (OCTA) in two cases of torpedo maculopathy using swept-source OCTA technology (DRI OCT Triton; Topcon Medical Systems, Oakland, NJ).

Case Reports

Case 1

A 19-year-old asymptomatic female with visual acuity (VA) of 6/7.5 in the right eye and 6/6 in the left eye was noted to have a well-demarcated, torpedo-shaped, flat lesion of the temporal macula of her right eye (Figure 1A). OCT demonstrated posterior choroidal excavation with overlying subretinal cleft (Figure 1B).

Imaging of torpedo lesion from Case 1. (A) Color fundus photo demonstrating typical appearance and location of torpedo lesion. (B) Optical coherence tomography (OCT) of torpedo lesion that shows outer retinal cavitation. (C) OCT angiography (OCTA) segment; superficial plexus of inner retina showing fine vessel loss at the site of the lesion. (D) OCTA segment; deep plexus of inner retina showing fine vessel loss at the site of the lesion. (E) OCTA segment; outer retina demonstrating visibility of the larger choroidal vessels at lesion site. (F) OCTA segment; choriocapillaris demonstrating visibility of the larger choroidal vessels at lesion site.

Figure 1.

Imaging of torpedo lesion from Case 1. (A) Color fundus photo demonstrating typical appearance and location of torpedo lesion. (B) Optical coherence tomography (OCT) of torpedo lesion that shows outer retinal cavitation. (C) OCT angiography (OCTA) segment; superficial plexus of inner retina showing fine vessel loss at the site of the lesion. (D) OCTA segment; deep plexus of inner retina showing fine vessel loss at the site of the lesion. (E) OCTA segment; outer retina demonstrating visibility of the larger choroidal vessels at lesion site. (F) OCTA segment; choriocapillaris demonstrating visibility of the larger choroidal vessels at lesion site.

OCTA revealed possible fine vessel loss at the site of the lesion in the superficial and deep capillary plexus. Large outer choroidal vessels were visible on the outer retinal and choriocapillaris slabs, potentially due to loss of the overlying RPE and choriocapillaris (Figures 1C–1F).

Case 2

A 46-year-old asymptomatic female with VA of 6/6 bilaterally was found to have a well-demarcated, flat, torpedo-shaped lesion in the temporal macula of her right eye (Figure 2A). On FAF, hypoautofluorescence of the pigmented portion was noted (Figure 2B). On OCTA, the superficial and deep capillary plexus density showed patchy loss at the lesion site, with preservation of the foveal avascular zone (FAZ). Similarly to Case 1, OCTA demonstrated increased visibility of the outer choroidal vasculature due to loss of overlying RPE and choriocapillaris (Figures 2C–2F).

Imaging of torpedo lesion from Case 2. (A) Color fundus photo showing the classical appearance and location of torpedo maculopathy. (B) Fundus autofluorescence of torpedo lesion demonstrating hypoautofluorescence consistent with retinal pigment epithelium loss. (C) Optical coherence tomography angiography (OCTA) segment; superficial plexus of inner retina showing fine vessel loss at the site of the lesion. (D) OCTA segment; deep plexus of inner retina showing fine vessel loss at the site of the lesion. (E) OCTA segment; outer retina demonstrating visibility of the larger choroidal vessels at lesion site. (F) OCTA segment; choriocapillaris demonstrating visibility of the larger choroidal vessels at lesion site. (G) OCT of torpedo lesion.

Figure 2.

Imaging of torpedo lesion from Case 2. (A) Color fundus photo showing the classical appearance and location of torpedo maculopathy. (B) Fundus autofluorescence of torpedo lesion demonstrating hypoautofluorescence consistent with retinal pigment epithelium loss. (C) Optical coherence tomography angiography (OCTA) segment; superficial plexus of inner retina showing fine vessel loss at the site of the lesion. (D) OCTA segment; deep plexus of inner retina showing fine vessel loss at the site of the lesion. (E) OCTA segment; outer retina demonstrating visibility of the larger choroidal vessels at lesion site. (F) OCTA segment; choriocapillaris demonstrating visibility of the larger choroidal vessels at lesion site. (G) OCT of torpedo lesion.

A diagnosis of torpedo maculopathy was rendered in both cases.

Discussion

Torpedo maculopathy is a rare clinical finding. In contrast to other RPE defects, its location and shape is nonrandom; it is a well-demarcated lesion with characteristic appearance situated in the temporal macula with a tip pointing toward the fovea.1,2 Patients are usually asymptomatic; however, they may demonstrate a paracentral scotoma.2–4

Although these features have little variation, findings on imaging can be more diverse, which may reflect a variety of etiologies that could lead to this anomaly.5

OCT findings can be variable with varying degrees of signal intensity being reported from the RPE.2,3,5 Wong et al. described two patterns of abnormality that may be found; Type 1 demonstrated outer retina attenuation without outer retinal cavitation, whereas Type 2 demonstrated both outer retinal attenuation and outer retinal cavitation which appears to be present in Case 1 described here.3

Findings with autofluorescence are also wide-ranging.5 Short wave FAF has revealed patterns of both normal and hypoautofluorescence (as in Case 2 presented here, consistent with RPE loss and masking from localized hyperpigmentation), with also some reports of localized hyperautofluorescence.2,3 Fluorescein angiography in cases of torpedo maculopathy has shown hyperfluorescence in the form of a window defect over the lesion due to overlying RPE atrophy.3

In the cases presented here, using swept-source OCTA, a common feature detected is the loss of RPE and choriocapillaris allowing greater visualization of larger vessels in the outer choroid. To confirm it is indeed larger vessels being visualized, manual segmentation of the inner choroid was done for both cases to highlight the deeper vessels (Figures 3 and 4). Interestingly, although OCTA technology is supposed to offer flow characteristics of vascular tissue confined within the segmented layer at any one time, flow in the outer choroidal vasculature is evident in both cases. A potential explanation for this phenomenon is that the segmentation curves used to delineate the tissue planes included in the flow detection processing are not absolute boundaries but rather represent gradients including areas of tissue on either side of the segmentation curves.6 The cases presented here confirm the potential of OCTA to provide greater detail of retinal and choroidal architecture and allow greater insight into the histopathology of retino-choroidal lesions through providing both structural and flow information in a single non-invasive imaging test.

The layer function on the B-scan (A) demonstrates the area that is being delineated. Manual segmentation of the choriocapillaris slab from Case 1 (B) confirms that it is the larger choroidal vessels that are being visualized.

Figure 3.

The layer function on the B-scan (A) demonstrates the area that is being delineated. Manual segmentation of the choriocapillaris slab from Case 1 (B) confirms that it is the larger choroidal vessels that are being visualized.

The layer function on the B-scan (A) demonstrates the area that is being delineated. Manual segmentation of the choriocapillaris slab from Case 2 (B) confirms that it is the larger choroidal vessels that are being visualized.

Figure 4.

The layer function on the B-scan (A) demonstrates the area that is being delineated. Manual segmentation of the choriocapillaris slab from Case 2 (B) confirms that it is the larger choroidal vessels that are being visualized.

References

  1. Shields CL, Guzman JM, Shapiro MJ, Fogel LE, Shields JA. Torpedo maculopathy at the site of the fetal “bulge.”Arch Ophthalmol. 2010;128(4):499–501. doi:10.1001/archophthalmol.2010.29 [CrossRef]
  2. Golchet PR, Jampol LM, Mathura JR Jr., Daily MJ. Torpedo maculopathy. Br J Ophthalmol. 2010;94(3):302–306. doi:10.1136/bjo.2009.162669 [CrossRef]
  3. Wong EN, Fraser-Bell S, Hunyor AP, Chen FK. Novel optical coherence tomography classification of torpedo maculopathy. Clin Exp Ophthalmol. 2015;43(4):342–348. doi:10.1111/ceo.12435 [CrossRef]
  4. Sanabria MR, Coco RM, Sanchidrian M. Oct findings in torpedo maculopathy. Retin Cases Brief Rep. 2008;2(2):109–111. doi:10.1097/ICB.0b013e318033a130 [CrossRef]
  5. Trevino R, Kiani S, Raveendranathan P. The expanding clinical spectrum of torpedo maculopathy. Optom Vis Sci. 2014;91(4 Suppl 1):S71–78. doi:10.1097/OPX.0000000000000181 [CrossRef]
  6. Spaide RF, Fujimoto JG, Waheed NK. Image artifacts in optical coherence tomography angiography retina. Retina. 2015;35(11):2163–2180. doi:10.1097/IAE.0000000000000765 [CrossRef]
Authors

From Manchester Royal Eye Hospital and University of Manchester, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK (ZA, KJ, TMA, KB); Wills Eye Hospital, Philadelphia (CLS); Centre for Ophthalmology and Vision Sciences, Institute of Human Development, University of Manchester, Manchester, UK (TMA); University of Manchester, Manchester, UK (TMA); and Heriot Watt University, Edinburgh Campus, Edinburgh, Scottland (TMA).

The authors report no relevant financial disclosures.

Address correspondence to Zaria Ali, MBChB, Manchester Royal Eye Hospital, Oxford Road, Manchester M13 9WL United Kingdom; email: zariaali@doctors.org.uk.

Received: February 04, 2017
Accepted: June 02, 2017

10.3928/23258160-20171030-10

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