Spark ImageWise 40 - Suraj Eye Institute

Optical Coherence Tomography features of a retinal capillary macro-aneurysm

Dr. Shashank Somani, Dr. Sarang Lambat, Dr. Prabhat Nangia, Dr. Vinay Nangia
Suraj Eye Institute, 559, New Colony, Sadar, Nagpur- 440001.

Case Description
A male, 68 years of age, came with complaints of gradual progressive diminution of vision in the right eye, since 1 year. He was known case of diabetes mellitus and systemic hypertension since 35 years. His best corrected visual acuity was 6/12(p), N12 in right eye (RE) and 6/9, N8 in left eye (LE). Anterior segment examination showed presence of grade 1 nuclear sclerosis in both the eyes. Intraocular pressure recorded by Goldmann applanation tonometer was 10 mmHg in both eyes.

**Figure 1 and Figure 2** shows fundus photograph of right eye and left eye respectively with clear media. In both eyes, the optic disc shows mild pallor of temporal neuro retinal rim and temporal parapapillary atrophy. Major blood vessels appears to be normal. There is presence of multiple microaneurysms and dot haemorrhages at macula in both eyes (yellow arrow). A single large macro aneurysm is seen in the RE temporal to fovea (green box). Probable onset of fibrosis can be appreciated surrounding the macro-aneurysm. One more possible macro-aneurysm can be seen just below the larger macro-aneurysm (Blue arrow).
The highlighted part in Figure 2 (black box) shows multiple micro-aneurysms in the area temporal to fovea.

**Figure 3** shows OCT image of line scan passing through fovea of right eye. There is loss of normal foveal contour and presence of diffuse retinal thickening in outer nuclear layer and cystoid edema in outer plexiform and outer nuclear layer (Green arrow). Fibrotic upper wall of macro-aneurysm can be seen temporal to the fovea (yellow arrow)

**Figure 4** shows OCT of left eye with a line scan passing through fovea. A thin hyper reflective membrane like structure is seen in the vitreous cavity suggestive of separation of hyaloid from the retina (green arrow). There is presence of diffuse retinal thickening in outer nuclear and inner nuclear layer temporal to fovea (diffuse macular edema) (yellow arrow) along with multiple cystic spaces in the outer nuclear layer of retina (Cystoid macular edema) (cyan arrow) which are compressing the surrounding retinal tissue. Hard exudates can be seen in the form of multiple hyper reflective spots. (Red arrow)

**Figure 5** shows an oblique line scan passing through the macro-aneurysm. The macro-aneurysm can be seen characteristically elevating the internal limiting membrane and retinal ganglion cell layer (Green arrow). The macro-aneurysm is seen to be pressing on the ellipsoid zone, interdigitation zone and retinal pigment epithelium. Shadowing effect can be seen below the macro-aneurysm. It has altered the normal retinal architecture in the adjacent retina. The vertical height of the outer surface of the wall of macro-aneurysm is 248um and the vertical height of the inner surface of the wall of macro-aneurysm is 204um. The horizontal diameter of the inner surface of wall is 150um and the outer surface of wall is 244um. Minimal intra-retinal fluid can be seen in the area adjacent to the macro-aneurysm.

**Figure 6** shows Fundus Fluorescein Angiography of RE in different phases.
Figure 6a: Early arteriovenous phase in which we can see hyperfluorescence in the area of macro-aneurysm.
Figure 6b: Late arteriovenous phase showing multiple micro-anueysms and increase in the intensity of hyperfluorescence in the area of macro-aneurysm without any significant leakage. The cystoid macular edema can be seen in a faint petaloid appearance. (Green arrow)
Figure 6c: Recirculation phase showing minimal diffuse leakage from the macro-aneurysm

The patient was advised to undergo intravitreal inj Anti-VEGF in both the eyes followed by macular laser. The patient took injection in right eye on 20-11-20.

**Figure 7:** Shows follow up oblique line scan passing through the macro-aneurysm. The walls of the macro aneurysm are not so clearly defined as before. Note the increased hyperreflectivity at the apex of the macro-aneurysm.

Discussion
Retinal capillary macroaneurysms (RCMs) are considered to be solitary outpouchings from the retinal capillaries and are distinct from the capillary micro aneurysm and retinal artery macroaneurysm (RAMs). One of the study, the aneurysms found in central retinal vein occlusion were noted to have a maximal diameter of 65 ± 39 microns and that in diabetic retinopathy to be 100 ± 57 microns. In contrast the size of RAMs ranges from 100 – 250 microns. There are 2 factors which facilitate enlargement of RCMs, one is decreasing wall strength and other is increasing wall tension. When these 2 factors come in play the lesion grows larger and leads to expansion of the RCMs.

Generally the RAMs are present in the inner retinal layers but RCMs are present in the outer retinal layers and was associated with minimal intraretinal fluid adjacent to the macro-aneurysm. Intervention may be required in cases of exudative or hemorrhagic macro-aneurysms. Different modalities of treatment include Laser photocoagulation or Anti-vascular endothelial growth factor therapy have been described for RAMs. Photocoagulation is known to produce coagulative necrosis of cells and coagulation of the blood within the RCM and it was shown to involution of the lesion and resolution of the leakage. In this case the macro-aneurysm was relatively silent and was not causing any damage to the surrounding retina however there was a presence of cystoid edema in the macular area for which the patient was advised injection Anti-VEGF followed by macular laser.

Our patient showed an irregular shaped macro aneurysm clinically on the fundus photograph. (Fig. 1) There was also presence of white tissue surrounding the macro aneurysm specially in the superior half. The presence of fibrosis may be indicative that this aneurysm may not be ‘active’ and is unlikely to cause significant associated retinal pathology. A hint of fibrosis may also be visible in Fig. 3 (yellow arrow). The appearance of the macro aneurysm on the FFA ( Fig 6 b) gives a beaded appearance which may also be suggestive of fibrosis setting in. This can only be a good sign, in that it may indicate a ‘macro-aneurysm in resolution’. In this patient however there were multiple microaneurysms indicate of significant diabetic maculopathy resulting in macular oedema as seen in the images above.

ReadWise:

Spaide RF, Barquet LA. RETINAL CAPILLARY MACROANEURYSMS. Retina. 2019 Oct;39(10):1889-1895. doi: 10.1097/IAE.0000000000002406. PMID: 30489449.
Amoroso F, Pedinielli A, Colantuono D, Jung C, Capuano V, Souied EH, Miere A. Selective Photocoagulation of Capillary Macroaneurysms by Navigated Focal Laser. Ophthalmic Surg Lasers Imaging Retina. 2021 Jul;52(7):366-373. doi: 10.3928/23258160-20210628-02. Epub 2021 Jul 1. PMID: 34309425.

Dr. Sarang Lambat
MS, FRF
Consultant
Vitreoretinal services
Suraj Eye Institute
Nagpur
Email – education@surajeye.org

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Optical Coherence Tomography features of a retinal capillary macro-aneurysm

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