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CASE REPORT
Ahead of print publication  

Targeted laser photocoagulation of larger capillary aneurysms with rim in diabetic macular edema


1 Department of Vitreo-Retina, Sankara Eye Hospital, Shimoga, Karnataka, India
2 Department of Vitreo-Retina and Ocular Oncology, Sankara Eye Hospital, Bengaluru, Karnataka, India

Date of Submission25-May-2022
Date of Acceptance29-Jun-2022
Date of Web Publication01-Aug-2022

Correspondence Address:
Pradeep Sagar,
Department of Vitreo-Retina, Sankara Eye Hospital, Harakere, Shimoga - 577 202, Karnataka
India
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2211-5056.353130

  Abstract 


This is a retrospective series of five eyes of four cases with diabetic macular edema (DME) secondary to large capillary aneurysms. Larger capillary aneurysms were identified noninvasively based on the presence of white rim in color photograph. On optical coherence tomography (OCT), the larger capillary aneurysms were seen as vertically oval structures with heterogeneous lumen and hyperreflective margin. Two of the four eyes were treated with intravitreal therapy with poor response before considering laser photocoagulation. In one eye, laser photocoagulation was considered as primary therapy in view of the poor response to intravitreal therapy in the fellow eye. In one eye, intravitreal steroid with prompt laser was considered. In one eye, laser was considered as primary therapy. Complete obliteration of the capillary lumen was noted on OCT in all the five eyes after laser photocoagulation. Complete resolution of macular edema was noted in all the five eyes with no recurrence over a follow-up period of 4–18 months. DME secondary to larger capillary aneurysms responds well to targeted laser photocoagulation. These larger capillary aneurysms can be identified on clinical examination and color photograph by the presence of white rim and can be confirmed on OCT.

Keywords: Capillary macroaneurysm, diabetic macular edema, large capillary aneurysm, laser photocoagulation



How to cite this URL:
Sagar P, Biswal S, Shanmugam P M, Ravishankar H N, Pawar R. Targeted laser photocoagulation of larger capillary aneurysms with rim in diabetic macular edema. Taiwan J Ophthalmol [Epub ahead of print] [cited 2022 Sep 28]. Available from: https://www.e-tjo.org/preprintarticle.asp?id=353130




  Introduction Top


Diabetic macular edema (DME) is one of the leading causes of visual impairment in patients with diabetic retinopathy.[1],[2] Leak from microaneurysms and incompetent capillaries result in macular edema. Microaneurysms are usually tiny and measure 50–100 μ in size.[3] However, larger aneurysms arising from the retinal capillaries are described in diabetic retinopathy and retinal vein occlusions. Macular edema due to larger aneurysms responds poorly to intravitreal anti-vascular endothelial factor (VEGF) therapy and responds well to laser photocoagulation.[4] Indocyanine green angiography (ICGA) and infrared reflectance imaging are described to be better imaging modalities in the identification of such larger aneurysms.[5],[6] In this series, we describe the identification of larger capillary aneurysms by color photograph and optical coherence tomography (OCT) and the successful treatment of macular edema by targeted laser photocoagulation.


  Case Reports Top


Case 1

A 59-year-old gentleman with right eye moderate nonproliferative diabetic retinopathy (NPDR) and DME was noted to have no improvement in macular edema at 1 month following intravitreal bevacizumab (1 dose). Best-corrected visual acuity (BCVA) in the right eye was 6/18. Fundus examination showed circinate retinopathy temporal to the fovea. A large aneurysm with a white rim was seen at the center of hard exudate ring. On OCT, the vertical diameter of the aneurysm was 255 μ and central foveal thickness (CFT) was 268 μ (measured by caliper from internal limiting membrane to retinal pigment epithelium). Targeted focal laser photocoagulation (spot size: 50 μ, duration: 100 mS, power: 70 mW, frequency-doubled Nd: YAG laser) was performed to achieve complete blanching of the aneurysm. After 2 months, the vertical diameter of the aneurysm reduced to 213 μ and CFT was 170 μ. At the center of the fovea, the subretinal fluid and intraretinal fluid were completely resolved and the BCVA improved to 6/6 [Figure 1]. There was no recurrence of macular edema at 6 months of follow-up. On OCT angiography (OCTA), the aneurysm was not detectable both at presentation and after treatment.
Figure 1: Case 1 – (a) Fundus photograph showing aneurysm with rim (white circle) with surrounding hard exudates. (b) Fundus photograph showing sclerosis of the aneurysm (white circle) following laser photocoagulation. (c) Optical coherence tomography showing the presence of subfoveal fluid and intraretinal fluid. (d) Optical coherence tomography showing complete resolution of subretinal fluid and intraretinal fluid, 2 months following laser photocoagulation. (e) Optical coherence tomography corresponding to the aneurysm showing hyper reflective wall with heterogeneous lumen (yellow arrow). (f) Optical coherence tomography corresponding to the aneurysm showing homogeneous oval structure (yellow arrow) suggestive of occluded aneurysm, 2 months following laser photocoagulation

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Case 2

A 75-year-old gentleman with bilateral moderate NPDR and DME was noted to have poor response to intravitreal bevacizumab (3 doses), triamcinolone (2 doses) and dexamethasone implant (2 doses) in the left eye. During therapy with intravitreal agents, there was no significant reduction in macular thickness at any point of time. BCVA in the right eye was 6/12 and the left eye was 6/18. Fundus examination of the left eye showed a large aneurysm with white rim and intraretinal hemorrhage temporal to the fovea. On OCT, the CFT was 559 μ and the size of the aneurysm was 328 μ. Fundus examination of the right eye showed two large aneurysms with white rim nasal to the fovea. On OCT, the CFT was 472 μ and the diameter of the largest aneurysm was 178 μ. Targeted focal laser photocoagulation (spot size: 50 μ, duration: 100 mS, power: 80 mW, frequency-doubled Nd: YAG laser) of the large aneurysms was performed. At 1-month follow-up, there was minimal reduction in retinal thickness in both eyes. At 3 months of follow-up, resolution of macular edema was noted in both the eyes. CFT in the left eye was 144 μ and the vertical diameter of the aneurysm reduced to 183 μ [Figure 2]. CFT in the right eye was 151 μ and the vertical diameter of the largest aneurysm reduced to 93 μ [Figure 3]. His BCVA improved to 6/9 in both the eyes. At 6, 12, and 18 months of follow-up, there was no recurrence of edema.
Figure 2: Left eye of Case 2 – (a) Fundus photograph showing aneurysm with rim (white circle). (b) Fundus photograph showing sclerosis of aneurysm and resolution of hard exudates, 3 months following laser photocoagulation. (c) Optical coherence tomography showing the presence of longstanding intraretinal cystoid space and the aneurysm is seen as an oval structure with hyperreflective wall and heterogeneous lumen (yellow arrow). (d) Optical coherence tomography showing normal foveal contour, 3 months following laser photocoagulation and homogeneous oval structure (yellow arrow) suggestive of occluded aneurysm

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Figure 3: Right eye of Case 2 – (a) Fundus photograph showing two aneurysms with white rim (white circle). (b) Aneurysms are not seen on fundus photograph, 3 months following laser photocoagulation. (c) Optical coherence tomography showing the presence of intraretinal cystoid space at the fovea. (d) Optical coherence tomography showing normal foveal contour 3 months following laser photocoagulation. (e) Optical coherence tomography corresponding to the aneurysms showing two oval structures with hyperreflective wall and heterogeneous lumen (yellow arrow). (f) Optical coherence tomography corresponding to the aneurysms showing homogeneous oval structures (yellow arrows) suggestive of occluded aneurysms

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Case 3

A 46-year-old gentleman presented with sudden-onset central scotoma in the right eye of 3 days duration. BCVA in the right eye was 6/36. On fundus examination, the right eye showed moderate NPDR with the presence of subretinal fluid at the fovea. Two large aneurysms with white rim were noted temporal to optic disc. On OCT, the subfoveal fluid was seen to be communicating with intraretinal cystoid spaces adjacent to large aneurysms. CFT was 425 μ and the vertical diameter of the largest aneurysm was 225 μ. On OCTA, the aneurysm could not be identified. Intravitreal triamcinolone 2 mg was administered in the right eye. Reduction of subretinal fluid was noted at 1-week follow-up (345 μ). Targeted laser photocoagulation (spot size: 50 μ, duration: 100 mS, power: 100 mW, frequency-doubled Nd: YAG laser) of the largest aneurysm was performed. The other aneurysm was not treated as it was located over the papillomacular bundle. Complete resolution of subretinal fluid was noted at 6-week follow-up. Intraretinal edema adjacent to the treated aneurysm was completely resolved, but the edema adjacent to the untreated aneurysm was persistent. CFT was 141 μ and the vertical diameter of the largest aneurysm was 110 μ [Figure 4]. There was no recurrence of edema at the last follow-up at 6 months.
Figure 4: Case 3 – (a) Fundus photograph showing aneurysm with rim (white circle). The yellow circle indicates the aneurysm overlying papillomacular bundle which was untreated. (b): Fundus photograph showing sclerosis of aneurysms, 6 weeks following laser photocoagulation. (c) Optical coherence tomography showing the presence of subretinal fluid at the fovea and intraretinal fluid adjacent to aneurysm (yellow arrow). (d) Optical coherence tomography showing normal foveal contour and homogeneous oval structure (yellow arrow) suggestive of occluded aneurysms

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Case 4

A 59-year-old woman was referred for the management of DME. On examination, the right eye had severe NPDR and the left eye had PDR with DME. A large capillary aneurysm with rim was noted superotemporal to the fovea. BCVA in the left eye was 6/12. On OCT, the subfoveal fluid was seen to be communicating with intraretinal cystoid spaces adjacent to large aneurysms. The CFT in the left eye was 274 μ and the vertical diameter of the aneurysm was 465 μ. Targeted laser photocoagulation (spot size: 50 μ, duration: 100 mS, power: 100 mW, frequency-doubled Nd: YAG laser) of the aneurysm was performed. Pan-retinal photocoagulation was performed simultaneously in 3 sitting. Complete resolution of macular edema was noted at 1-month follow-up. CFT at 1 month was 172 μ, BCVA in the left eye improved to 6/6 and the aneurysm showed homogeneous internal reflectivity. There was no recurrence of edema at the last follow-up at 4 months [Figure 5].
Figure 5: Case 4 – (a) Fundus photograph showing aneurysm with rim (white circle). (b) Fundus photograph showing sclerosis of aneurysms (white circle), 1 month following laser photocoagulation. (c) Optical coherence tomography showing the presence of subretinal fluid at the fovea and intraretinal fluid adjacent to aneurysm (yellow arrow). (d) Optical coherence tomography showing normal foveal contour and homogeneous oval structure (yellow arrow) suggestive of occluded aneurysms

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  Discussion Top


Microaneurysms are saccular or fusiform dilatation of retinal capillaries and are the earliest detectable clinical sign of diabetic retinopathy. Although aneurysms arising from the capillaries are typically small, larger aneurysms can arise from the capillaries. Such larger aneurysms are described in the literature with various synonyms, such as perifoveal vascular anomalous complex (PEVAC),[7] retinal capillary macroaneurysms (RCMs),[4] capillary macroaneurysms,[8] and telangiectatic capillaries (TelCaps).[5]

The term PEVAC is used to describe perifoveal capillary dilatation, resulting in exudation and macular edema. Initially, the capillary dilatation in eyes without known retinal vascular diseases was described as PEVAC; however, recently, the capillary dilatation larger than the typical microaneurysms in DME is also described as PEVAC by a few authors.[7] Spaide and Barquet reported larger aneurysms (>200 μ) arising from the retinal capillaries and described them as RCM.[4] Bourhis et al. described the aneurysms larger than 100 μ in diabetic retinopathy as capillary macroaneurysms.[8] Castro Farías et al. termed the aneurysms larger than 150 μ as TelCaps to avoid confusion between arterial macroaneurysm and capillary macroaneurysm.[5]

Bourhis et al. described that ICGA and high-resolution OCT help in better visualization of capillary macroaneurysms, with OCT being more sensitive due to visualization of wall of aneurysm.[8] Castro Farías et al. also described that ICGA helps in the identification of TelCaps in eyes with DME.[5] Roh et al. described that infrared reflectance image helps in the identification of TelCaps.[6] In the present study, we identified the larger capillary aneurysms noninvasively based on the presence of white rim in color photograph. On OCT, the larger capillary aneurysms were seen as vertically oval structures with heterogeneous lumen and hyperreflective margin. The larger capillary aneurysms were not detectable on OCTA, probably due to low-flow velocity.

Macular edema in eyes with PEVAC responds poorly to intravitreal anti-VEGF therapy.[7] Similarly, Spaide and Barquet reported that RCM had partial or poor response to intravitreal anti-VEGF therapy and targeted laser photocoagulation of these aneurysms resulted in rapid resolution of edema and regression of the aneurysm.[4] Paques et al. noted that chronic DME refractory to intravitreal anti-VEGF therapy had better anatomical and functional outcomes following ICGA-guided photocoagulation of capillary macroaneurysms.[9] Roh et al. noted that laser photocoagulation of “TelCaps” results in the resolution of edema.[6]

In this study, laser photocoagulation of the larger capillary aneurysms with white rim resulted in complete resolution of macular edema within 3 months in all the eyes. In Case 2, laser photocoagulation was considered following poor response to intravitreal therapy. In the fellow eye, laser photocoagulation was considered as primary therapy in view of the poor response to intravitreal therapy in the other eye. In Case 1, laser photocoagulation was performed after 1 month of intravitreal bevacizumab as there was no reduction in edema following bevacizumab therapy. In Case 3, intravitreal steroid with prompt laser was considered. Hence, in this case, it would not be possible to claim that laser alone is responsible for the resolution of macular edema. However, considering the fact that the edema did not recur for 6 months, it would be possible that the laser had a definite role in occlusion of the larger capillary aneurysm, which was probably the main reason for macular edema in this case. In Case 4, laser photocoagulation was considered as primary therapy. Complete obliteration of the capillary lumen was noted on OCT in all the five eyes after laser photocoagulation. In all the five eyes, there was no recurrence of macular edema, which indicates that large capillary aneurysms were primarily responsible for macular edema in these cases. The limitations of the study are small sample size and retrospective nature. As the management protocol was different in each case, it would be difficult to suggest the timing of laser. However, it is noteworthy that laser photocoagulation was the primary therapy in two eyes, and in another eye, laser photocoagulation was performed as the macular edema was not responding to intravitreal anti-VEGF and steroid implant.

DME can occur secondary to larger capillary aneurysms. These larger capillary aneurysms can be identified on clinical examination and color photographs by the presence of white rim and can be confirmed on OCT. DME due to larger capillary aneurysms responds well to targeted laser photocoagulation with long-term remission of macular edema. Hence, focal laser photocoagulation should be considered in eyes with DME, if larger capillary aneurysms with rim are seen in the edematous area. Further studies are required to confirm these findings.

Consent and ethical committee approval

Institute ethics committee approval was obtained on December 4, 2020 (Institute Ethics Committee, Sankara Eye Hospital, Shimoga). Written informed consent was obtained from all the study participants.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for 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.

Financial support and sponsorship

Nil.

Conflicts of interest

The authors declare that there are no conflicts of interests of this paper.



 
  References Top

1.
Ding J, Wong TY. Current epidemiology of diabetic retinopathy and diabetic macular edema. Curr Diab Rep 2012;12:346-54.  Back to cited text no. 1
    
2.
Singh R, Ramasamy K, Abraham C, Gupta V, Gupta A. Diabetic retinopathy: An update. Indian J Ophthalmol 2008;56:178-88.  Back to cited text no. 2
    
3.
Dubow M, Pinhas A, Shah N, Cooper RF, Gan A, Gentile RC, et al. Classification of human retinal microaneurysms using adaptive optics scanning light ophthalmoscope fluorescein angiography. Invest Ophthalmol Vis Sci 2014;55:1299-309.  Back to cited text no. 3
    
4.
Spaide RF, Barquet LA. Retinal capillary macroaneurysms. Retina 2019;39:1889-95.  Back to cited text no. 4
    
5.
Castro Farías D, Matsui Serrano R, Bianchi Gancharov J, de Dios Cuadras U, Sahel J, Graue Wiechers F, et al. Indocyanine green angiography for identifying telangiectatic capillaries in diabetic macular oedema. Br J Ophthalmol 2020;104:509-13.  Back to cited text no. 5
    
6.
Roh HC, Lee C, Kang SW, Choi KJ, Eun JS, Hwang S. Infrared reflectance image-guided laser photocoagulation of telangiectatic capillaries in persistent diabetic macular edema. Sci Rep 2021;11:21769.  Back to cited text no. 6
    
7.
Sacconi R, Freund KB, Yannuzzi LA, Dolz-Marco R, Souied E, Capuano V, et al. The expanded spectrum of perifoveal exudative vascular anomalous complex. Am J Ophthalmol 2017;184:137-46.  Back to cited text no. 7
    
8.
Bourhis A, Girmens JF, Boni S, Pecha F, Favard C, Sahel JA, et al. Imaging of macroaneurysms occurring during retinal vein occlusion and diabetic retinopathy by indocyanine green angiography and high resolution optical coherence tomography. Graefes Arch Clin Exp Ophthalmol 2010;248:161-6.  Back to cited text no. 8
    
9.
Paques M, Philippakis E, Bonnet C, Falah S, Ayello-Scheer S, Zwillinger S, et al. Indocyanine-green-guided targeted laser photocoagulation of capillary macroaneurysms in macular oedema: A pilot study. Br J Ophthalmol 2017;101:170-4.  Back to cited text no. 9
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]



 

 
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