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 Table of Contents  
Year : 2022  |  Volume : 2  |  Issue : 1  |  Page : 292-293

Chimney leak in proliferative diabetic retinopathy

1 Department of Retina and Vitreous, Narayana Nethralaya, Bangalore, Karnataka, India
2 University of Pittsburgh School of Medicine, Medical Retina and Vitreoretinal Surgery, Pittsburg, PA, USA

Date of Submission07-May-2021
Date of Acceptance23-Aug-2021
Date of Web Publication07-Jan-2022

Correspondence Address:
Dr. Ramesh Venkatesh
Narayana Nethralaya, #121/C, Chord Road, 1st R block Rajaji Nagar, Bangalore - 560 010, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijo.IJO_1139_21

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Keywords: Chimney leak, fluorescein angiography, leakage pattern, proliferative diabetic retinopathy

How to cite this article:
Reddy NG, Venkatesh R, Agrawal S, Mishra P, Chhablani J. Chimney leak in proliferative diabetic retinopathy. Indian J Ophthalmol Case Rep 2022;2:292-3

How to cite this URL:
Reddy NG, Venkatesh R, Agrawal S, Mishra P, Chhablani J. Chimney leak in proliferative diabetic retinopathy. Indian J Ophthalmol Case Rep [serial online] 2022 [cited 2022 Jan 19];2:292-3. Available from: https://www.ijoreports.in/text.asp?2022/2/1/292/334856

A 62-year-old female, diabetic for 20 years, was referred for diabetic retinopathy (DR) screening. Corrected visual acuity was 6/6, 6/6RS in both eyes. Intraocular pressure and anterior segment examination were normal. Both eye fundus showed features of severe nonproliferative DR (SNPDR) with no macular edema. Right eye (RE) fundus showed a small red tuft of vessels along the superotemporal arcade suggestive of a suspicious retinal neovascularization (NV) [Figure 1]a. Optical coherence tomography scan through NV showed an elevated lesion on the retinal surface, protruding into the vitreous [Figure 1]b. A retinal NV was confirmed showing a late intense leakage on fluorescein angiography (FA). There was an interesting chimney-like leak emanating from the NV into the superior retinal periphery in late FA [Figure 2]a, [Figure 2]b, [Figure 2]c, [Figure 2]d, [Figure 2]e. Findings were suggestive of PDR in RE and SNPDR in the left eye.
Figure 1: Color fundus and optical coherence tomography (OCT) scans in a patient with proliferative diabetic retinopathy: (a) Color fundus photograph of the right eye using the Optos, Daytona showing possible retinal neovascularization (black arrow) along the superotemporal arcade in patient with diabetic retinopathy. (b) OCT line scan (Spectralis, Heidelberg) through the suspected NV shows the lesion to be elevated from the retinal surface and protruding toward the vitreous cavity (white arrow). There was no macular edema on OCT in the right eye

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Figure 2: (a–e) Chimney-like leakage from the retinal neovascularization due to proliferative diabetic retinopathy along the different phases of fluorescein angiogram

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  Discussion Top

We demonstrate an unusual FA leakage finding in PDR and pictorially call it “chimney leak.” Routinely, retinal NV demonstrates an intense diffuse leakage pattern during late FA. Leakage intensity from NV depends on the vasculature within it, associated vitreoretinal interface changes, and vitreous traction.[1],[2],[3],[4] No such change was noted in our case. Our hypothesis for this leakage pattern is similar to the mechanism of smoke-stack leak in central serous chorioretinopathy and retinal meteor-leak in vasoproliferative tumors.[5],[6] Retinal hypoxia causes retinal ischemia, which triggers retinal physiological and pathological changes. This creates pressure gradients across the vitreous, retina, and choroid, causing leakage of free fluorescein from the retinal vessels into the vitreous due to inner blood–retina barrier breakdown. There is a temperature difference across the different eye structures in DR.[7] The anterior part of the eye is cooler compared to its posterior part. This temperature difference between the cooler vitreous and warmer retina could stimulate the convection currents.

Thus, multiple factors such as high unbound fluorescein, pressure, and temperature difference between retina and vitreous and development of convection currents could precipitate this chimney-type leak in PDR.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Grading diabetic retinopathy from stereoscopic color fundus photographs--An extension of the modified airlie house classification. ETDRS report number 10. Early treatment diabetic retinopathy study research group. Ophthalmology 1991;98 (5 Suppl):786-806.  Back to cited text no. 1
Salz DA, Witkin AJ. Imaging in diabetic retinopathy. Middle East Afr J Ophthalmol 2015;22:145-50.  Back to cited text no. 2
[PUBMED]  [Full text]  
Rasta SH, Nikfarjam S, Javadzadeh A. Detection of retinal capillary nonperfusion in fundus fluorescein angiogram of diabetic retinopathy. Bioimpacts 2015;5:183-90.  Back to cited text no. 3
Cho H, Alwassia AA, Regiatieri CV, Zhang JY, Baumal C, Waheed N, et al. Retinal neovascularization secondary to proliferative diabetic retinopathy characterized by spectral domain optical coherence tomography. Retina 2013;33:542-7.  Back to cited text no. 4
Bujarborua D, Nagpal PN, Deka M. Smokestack leak in central serous chorioretinopathy. Graefes Arch Clin Exp Ophthalmol 2010;248:339-51.  Back to cited text no. 5
Venkatesh R, Gurav P, Dave PA, Roy S. Retinal meteor. Indian J Ophthalmol 2017;65:879-81.  Back to cited text no. 6
[PUBMED]  [Full text]  
Sodi A, Giambene B, Miranda P, Falaschi G, Corvi A, Menchini U. Ocular surface temperature in diabetic retinopathy: A pilot study by infrared thermography. Eur J Ophthalmol 2009;19:1004-8.  Back to cited text no. 7


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