Ophthalmic Surgery, Lasers and Imaging Retina

Images in Ophthalmology 

Unilateral Situs Inversus of the Optic Disc in a Patient With Retinal Arteriolar Tortuosity

Chia-Chen Hsu, MD; Kathy Ming Feng, MD; Yun-Hsiang Chang, MD

Abstract

Familial retinal arteriolar tortuosity (fRAT) is a rare autosomal dominant disorder that is characterized by tortuosity of the second- and third-order arterioles around the posterior pole of retina. Most cases with fRAT lack associated systemic vascular abnormality. Situs inversus, a congenital anomaly, features emergence of retinal vessels from the optic nerve head in a nasal direction, usually occurs bilaterally. In this case report, the authors describe a unique case of fRAT with unilateral situs inversus.

[Ophthalmic Surg Lasers Imaging Retina. 2020;51:533–535.]

Abstract

Familial retinal arteriolar tortuosity (fRAT) is a rare autosomal dominant disorder that is characterized by tortuosity of the second- and third-order arterioles around the posterior pole of retina. Most cases with fRAT lack associated systemic vascular abnormality. Situs inversus, a congenital anomaly, features emergence of retinal vessels from the optic nerve head in a nasal direction, usually occurs bilaterally. In this case report, the authors describe a unique case of fRAT with unilateral situs inversus.

[Ophthalmic Surg Lasers Imaging Retina. 2020;51:533–535.]

A 52-year-old male with hyperlipidemia presented for accidently noted retinal vascular anomaly. He received cataract surgery in his right eye (OD) 2 years ago and had experienced exercise-related vitreous hemorrhage with spontaneous recovery in his teens. He denied of diabetes mellitus or hypertension. Abnormal tortuosity of the retinal arterioles was already noted at that time. Both his father and brother have tortuous retinal arterioles, as well.

On examination, the bilateral best-corrected visual acuity was 20/20. The anterior segments were unremarkable except for right pseudophakia. Fundus examination demonstrated spiral arterioles of the second and third order at the macular and peripapillary area of bilateral eyes without periphery involvement. Furthermore, situs inversus of the optic disc in his left eye (OS) was observed (Figures 1A and 1B). The left eye with situs inversus of the optic disc exhibited thicker retinal nerve fiber layer (RNFL) in the nasal side, larger rim area (OD/OS: 1.34/2.59 mm2), and smaller cup-to-disc area ratio than the right eye as measured by optical coherence tomography (Figure 2). After a thorough investigation from imaging to blood tests, no other vascular abnormalities or systemic diseases could be found. A diagnosis of familial retinal arteriolar tortuosity (fRAT) accompanied by situs inversus of optic disc was made based on his retinal image and hereditary condition.

Fundus photographs of the right (A) and left eye (B) showed bilateral pronounced tortuosity of the second- and third-order arterioles in the macular and peripapillary region with situs inversus of the optic disc in the left eye (B).

Figure 1.

Fundus photographs of the right (A) and left eye (B) showed bilateral pronounced tortuosity of the second- and third-order arterioles in the macular and peripapillary region with situs inversus of the optic disc in the left eye (B).

Disc optical coherence tomography (OCT). Horizontal cross-section of the optic nerve head image (A, D), temporal-superior-nasal-inferior-temporal curve of the peripapillary retinal nerve fiber layer (RNFL) thickness profile along the 3.45 mm diameter circle (B, E), RNFL thickness measurement summarized in two quadrants (superior and inferior) and four sectors (superior, nasal, inferior, and temporal), and RNFL thickness map (C, F) provided by the spectral-domain OCT. The left eye with situs inversus of the optic disc (D–F) showed thicker RNFL in the nasal quadrant and smaller cup-to-disc ratio when compared to the right eye (A–C) without situs inversus of the optic disc.

Figure 2.

Disc optical coherence tomography (OCT). Horizontal cross-section of the optic nerve head image (A, D), temporal-superior-nasal-inferior-temporal curve of the peripapillary retinal nerve fiber layer (RNFL) thickness profile along the 3.45 mm diameter circle (B, E), RNFL thickness measurement summarized in two quadrants (superior and inferior) and four sectors (superior, nasal, inferior, and temporal), and RNFL thickness map (C, F) provided by the spectral-domain OCT. The left eye with situs inversus of the optic disc (D–F) showed thicker RNFL in the nasal quadrant and smaller cup-to-disc ratio when compared to the right eye (A–C) without situs inversus of the optic disc.

FRAT manifests as isolated torturous small arterioles confined to the posterior pole. Patients with fRAT may present with asymptomatic or symptomatic intraretinal or preretinal hemorrhages.1 Situs inversus of the optic disc is a distinct congenital condition with dysversion optic disc and the inserted vessels. This anomaly may be complicated with high myopia, tilted optic disc, or optic disc coloboma.2,3 The association between the coexisting situs inversus of the optic disc and fRAT in our patient remains unclear.

Sunah et al. described thicker RNFL in the nasal quadrant and smaller cup-to-disc ratio in the eyes with situs inversus of the optic disc compared to the normal eye.4 The result was consistent with our case.

Although several cases and literature of fRAT have been well described,1,5,6 to our knowledge, this is the first report of fRAT associated with unilateral situs inversus of the optic disc.

References

  1. Sutter FK, Helbig H. Familial retinal arteriolar tortuosity: a review. Surv Ophthalmol. 2003;48(3):245–255. doi:10.1016/S0039-6257(03)00029-8 [CrossRef] PMID:12745002
  2. Rao VA, Sambath T, Madhavaranga MP, Nair N. Optic nerve entrance coloboma associated with situs inversus. Indian J Ophthalmol. 2002;50(4):328–329. PMID:12532503
  3. Dorrell D. The tilted disc. Br J Ophthalmol. 1978;62(1):16–20. doi:10.1136/bjo.62.1.16 [CrossRef] PMID:629907
  4. Kang S, Jin S, Roh KH, Hwang YH. Peripapillary retinal nerve fiber layer and optic nerve head characteristics in eyes with situs inversus of the optic disc. J Glaucoma. 2015;24(4):306–310. doi:10.1097/IJG.0b013e31829e1ba2 [CrossRef] PMID:24048184
  5. Bartlett WJ, Price J. Familial retinal arteriolar tortuosity with retinal hemorrhage. Am J Ophthalmol. 1983;95(4):556–558. doi:10.1016/0002-9394(83)90282-9 [CrossRef] PMID:6837703
  6. Ding PC, Chen MT. Retinal arteriolar tortuosity with recurrent retinal hemorrhages—case report. Kaohsiung J Med Sci. 2000;16(7):380–382. PMID:11079298
Authors

From the Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, R.O.C.

The authors report no relevant financial disclosures.

Address correspondence to Yun-Hsiang Chang, MD, Department of Ophthalmology, Tri-Service General Hospital, National Defense Medical Center, No. 325, Section 2, Cheng-Kung Road, Neihu District, Taipei City, 11490, Taiwan, R.O.C.; email: yun.siang@me.com.

Received: April 10, 2020
Accepted: July 09, 2020

10.3928/23258160-20200831-09

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