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 Table of Contents  
CASE REPORT
Year : 2021  |  Volume : 1  |  Issue : 4  |  Page : 662-665

Bacillary layer detachment in a case of sympathetic ophthalmia: Presentation and pattern of resolution on swept-source optical coherence tomography


Department of Vitreo-retina and Uveitis, Shri Sadguru Seva Sangh Trust, Sadguru Netra Chikitsalaya, Chitrakoot, Madhya Pradesh, India

Date of Submission08-Jan-2021
Date of Acceptance10-Apr-2021
Date of Web Publication09-Oct-2021

Correspondence Address:
Dr. Alok Sen
Vitreo-Retina and Uveitis Services, Shri Sadguru Seva Sangh Trust, Sadguru Netra Chikitsalaya, Chitrakoot - 210 204, Madhya Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijo.IJO_75_21

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  Abstract 


The terminology of bacillary layer detachment (BLD) has been used vicariously to describe the splitting of the photoreceptor layers at the level of the myoids and has been discerned in multiple uveitic pathologies. To add to the existing literature, we report BLD in the acute stage of sympathetic ophthalmia presenting as an enclosed outer retinal cyst extending between the external limiting membrane and retinal pigment epithelium with disruption of the outer retinal layers and apparent splitting of the photoreceptor myoid zone at its margins. The cystic-appearing BLD collapsed following treatment with systemic steroids with improvement in vision.

Keywords: Bacillary layer detachment, optical coherence tomography, steroids, swept-source OCT, sympathetic ophthalmia


How to cite this article:
Shenoy P, Kohli GM, Bhatia P, Sen A. Bacillary layer detachment in a case of sympathetic ophthalmia: Presentation and pattern of resolution on swept-source optical coherence tomography. Indian J Ophthalmol Case Rep 2021;1:662-5

How to cite this URL:
Shenoy P, Kohli GM, Bhatia P, Sen A. Bacillary layer detachment in a case of sympathetic ophthalmia: Presentation and pattern of resolution on swept-source optical coherence tomography. Indian J Ophthalmol Case Rep [serial online] 2021 [cited 2021 Oct 18];1:662-5. Available from: https://www.ijoreports.in/text.asp?2021/1/4/662/327649



The anatomical terminology of “bacillary layer” was first coined by Polyak in 1941.[1] This terminology resurfaced again following the observations of Mehta et al.[2] in a case of toxoplasma retinochoroiditis showing a dome-shaped detachment of the overlying outer retina on optical coherence tomography (OCT), which they speculated to be analogous to the split in the bacillary layer. Subsequently, bacillary layer detachment (BLD) was also perceived in Vogt–Koyanagi–Harada (VKH) disease, posterior scleritis, acute posterior multifocal placoid pigment epitheliopathy, and tubercular choroidal granuloma.[3],[4],[5],[6] To add to the existing pathologies, we report the updated nomenclature of BLD in a case with sympathetic ophthalmia (SO) and chronicle its resolution on swept-source OCT (SS-OCT) after treatment.


  Case Report Top


A 26-year-old female presented with an alleged history of trauma to her left eye by a goat's horn. Her visual acuity (VA) was perception of light; slit-lamp examination revealed a scleral tear for which she underwent primary repair. The right eye examination was within normal limits. Six weeks after the initial trauma, the patient presented with complaints of diminution of vision in the right eye. The best-corrected visual acuity (BCVA) in the right eye was 20/400. Clinical examination of the right eye showed cellular reaction 2+ and granulomatous keratic precipitates with fundus examination revealing a hyperemic disc [Figure 1]a. The left eye had a sutured scleral tear and vitreous hemorrhage.
Figure 1: Clinical picture at presentation shows the hyperemic disc (a) with fundus fluorescein angiography demonstrating disc hyperfluorescence and multiple pin-point leaks (b). The SS-OCT through the macula (c) reveals RPE undulations and a dome-shaped intraretinal cystic cavity (hashtag) with the apparent splitting of the photoreceptor ellipsoid zone at its margin suggestive of a BLD (yellow arrow). The inner hyperreflective band (green arrow) corresponds to the myoids and the outer hyperreflective band corresponds to the residual myoid fragments, ellipsoids, and the outer retinal layers (blue arrow). An SRF pocket is visible temporal to the fovea (yellow asterisk)

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Fundus fluorescein angiography (FFA) showed early disc hyperflouroscence and multiple pin-point hyperflouroscent leaks [Figure 1]b. The SS-OCT of the right eye showed an undulating retinal pigment epithelium (RPE) with the presence of subretinal fluid (SRF) temporal to the macula. Subfoveally, an intraretinal cystic space was seen involving the outer retinal layers with internal hyperreflective thread-like structures. The margins of this cystic space appeared to be continuous with the ellipsoid zone (EZ) of the normal retina with an apparent splitting of the photoreceptors layer, suggestive of a BLD [Figure 1]c. A clinical diagnosis of right SO was made, which was supported by corroborative OCT and FFA findings.

The patient was initiated on intravenous pulse dexamethasone 3 mg/kg body weight/day for a period of 5 days along with topical steroids and cycloplegics. Three days posttreatment, the BCVA improved to 20/120, and the SS-OCT showed a reduction in the RPE undulation, the height of SRF, and BLD [Figure 2]a. Five days later the BCVA further improved to 20/80 while the SRF and BLD height further decreased with a hyperreflective granularity above the RPE [Figure 2]b. On the sixth day (after five doses of IV [intravenous] steroids), there was a normalization of the RPE contour and resolution of the BLD, with a collection of SRF subfoveally [Figure 2]c. The patient was discharged on oral steroids (1 mg/kg body weight) and azathioprine (2 mg/kg body weight). A week later, the BCVA was maintained at 20/80 and the fundus showed a reduction in disc hyperemia with pigmentary alterations at the posterior pole [Figure 3]a. The SS-OCT revealed the resolution of the SRF pocket; however, the EZ could not be clearly demarcated [Figure 3]b. Two months later, the BCVA in the right eye improved to 20/20. Fundus evaluation revealed a normal disc with pigmentation at the macula [Figure 3]c. The SS-OCT showed restoration of the foveal contour with a distinct external limiting membrane (ELM) and subfoveal EZ [Figure 3]d.
Figure 2: The sequential reduction of the BLD, SRF, and RPE undulations on OCT is shown on Day 3 (a) and Day 5 (b) following treatment. On Day 6 (c), the BLD resolved and a subfoveal SRF pocket (asterisk) was visible with a cuff of hyperreflective dots (arrowheads)

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Figure 3: The fundus picture a week after initiation of oral steroids and immunosuppressants shows a reduction in the disc hyperemia and pigmentary alterations at the macula (a). The SRF pocket is resolved on OCT (b) with a distinct external limiting membrane and RPE band. The ellipsoid and interdigitation zones are not clearly demarcated. Two months later, the fundus shows pigmentary changes at the macula (c) and the OCT shows foveal contour restoration and a distinct ellipsoid zone in the area corresponding to the BLD (d)

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  Discussion Top


The presence of BLD reflects a split between the inner segment myoids from the ellipsoids and the outer segment of the photoreceptor unit, resulting in the formation of two hyperreflective bands on OCT present within the dome-shaped intraretinal cystic cavity. The inner hyperreflective band is a composite of the split myoid fragments and the ELM, whereas the outer band comprises the residual myoid fragments, ellipsoids, and the outer retinal layers.[2]

Sympathetic ophthalmia is considered to be an autoimmune inflammatory response with retinal damage being produced either by cellular immunity against the retinal antigens or by melanin-containing structures and secondary to the mitochondrial oxidative stress.[7],[8],[9] Both of these can help explain the possible reason for the development of BLD in the hyperacute stage of SO, which in turn represents the ongoing nascent immune injury to the photoreceptors.

Before the terminology of BLD came into vogue, Gupta et al.[10] noted the presence of a pre-RPE moderately hyperreflective membrane in the acute phase of SO on Spectral Domain OCT. In our case of SO, we noted the splitting of the outer retinal layers correlating well to the pre-RPE “hyperreflective membrane” described by Gupta et al.[10] in their series.

Choroidal involvement in the form of ischemia or inflammation remains the common denominator in the various uveitic pathologies presenting with BLD.[11] Another proposed pathogenic mechanism contributing to BLD formation is sudden shear stress at the level of the bacillary layer owing to the massive fluid exudation.[4] In our case of SO, the presence of underlying choroidal involvement along with fluid exudation could have been contributory to the development of BLD.

We observed a sequential reduction in the height of the BLD and intraretinal fluid with the absorption of fibrin following treatment. Reports on the evolution of BLD following treatment remain scarce. Agarwal et al.[3] in their series of acute VKH noted BLD resolution before SRF with a significant improvement in VA. In our case of SO, the pattern was found to be similar, with the resolution of BLD preceding that of SRF and a parallel improvement in the vision.

The extent of this visual improvement following treatment in stromal choroidopathies such as VKH and SO has been attributed to the viability of the traumatized photoreceptors and their regenerative capacity.[10],[12] In our case, we observed that the photoreceptor regeneration in the area with BLD preceded the area with SRF. A possible explanation could be that BLD represents only a split in the photoreceptors rather than a true neurosensory detachment, thus resulting in faster photoreceptor reconstitution.

It remains difficult to speculate with conviction the exact pathogenesis of BLD based on a single case report. It would be interesting to analyze the incidence of BLD in SO while correlating it to the recurrences and the severity of inflammation for which larger samples and longer follow-ups remain essential.


  Conclusion Top


To summarize, BLD can present in the acute stage of SO and shows a swift resolution following treatment, evidenced as the reestablishment of the EZ following eventual reconstitution of the photoreceptor inner and outer segments.

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.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Polyak SL. The Retina: The Anatomy and the Histology of the Retina in Man, Ape, and Monkey, Including the Consideration of Visual Functions, The History of Physiological Optics, and the Histological Laboratory Technique. Chicago, IL: The University of Chicago Press; 1941; p. 607.  Back to cited text no. 1
    
2.
Mehta N, Chong J, Tsui E, Duncan JL, Curcio CA, Freund KB, et al. Presumed foveal bacillary layer detachment in a patient with toxoplasmosis chorioretinitis and pachychoroid disease. Retin Cases Brief Rep 2018. doi: 10.1097/ICB.0000000000000817. Online ahead of print.  Back to cited text no. 2
    
3.
Agarwal A, Freund KB, Kumar A, Aggarwal K, Sharma D, Katoch D, et al. Bacillary layer detachment in acute vogt-koyanagi-harada disease: A novel swept-source optical coherence tomography analysis. Retina 2021;41:774-83.  Back to cited text no. 3
    
4.
Cicinelli MV, Giuffré C, Marchese A, Jampol LM, Introini U, Miserocchi E, et al. The bacillary detachment in posterior segment ocular diseases. Ophthalmol Retina 2020;4:454-6.  Back to cited text no. 4
    
5.
Kohli GM, Bhatia P, Shenoy P, Sen A, Gupta A. Bacillary layer detachment in hyper-acute stage of acute posterior multifocal placoid pigment epitheliopathy: A case series. Ocul Immunol Inflamm 2020;1-4. doi: 10.1080/09273948.2020.1823423. Online ahead of print.  Back to cited text no. 5
    
6.
Markan A, Aggarwal K, Gupta V, Agarwal A. Bacillary layer detachment in tubercular choroidal granuloma: A new optical coherence tomography finding. Indian J Ophthalmol 2020;68:1944-6.  Back to cited text no. 6
[PUBMED]  [Full text]  
7.
Parikh JG, Saraswathy S, Rao NA. Photoreceptor oxidative damage in sympathetic ophthalmia. Am J Ophthalmol 2008;146:866-75.  Back to cited text no. 7
    
8.
Kaneko Y, Rao NA. Mitochondrial oxidative stress initiates visual loss in sympathetic ophthalmia. Jpn J Ophthalmol 2012;56:191-7.  Back to cited text no. 8
    
9.
Chu XK, Chan CC. Sympathetic ophthalmia: To the twenty-first century and beyond. J Ophthalmic Inflamm Infect 2013;3:49.  Back to cited text no. 9
    
10.
Gupta V, Gupta A, Dogra MR, Singh I. Reversible retinal changes in the acute stage of sympathetic ophthalmia seen on spectral domain optical coherence tomography. Int Ophthalmol 2011;31:105-10.  Back to cited text no. 10
    
11.
Fernández-Avellaneda P, Breazzano MP, Fragiotta S, Xu X, Zhang Q, Wang RK, et al. Bacillary layer detachment overlying reduced choriocapillaris flow in acute idiopathic maculopathy. Retin Cases Brief Rep 2019. doi: 10.1097/ICB.0000000000000943. Online ahead of print.  Back to cited text no. 11
    
12.
Ishihara K, Hangai M, Kita M, Yoshimura N. Acute Vogt-Koyanagi-Harada disease in enhanced spectral-domain optical coherence tomography. Ophthalmology 2009;116:1799-807.  Back to cited text no. 12
    


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