|Year : 2021 | Volume
| 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
Pratik Shenoy, Gaurav Mohan Kohli, Priyavrat Bhatia, Alok Sen
Department of Vitreo-retina and Uveitis, Shri Sadguru Seva Sangh Trust, Sadguru Netra Chikitsalaya, Chitrakoot, Madhya Pradesh, India
|Date of Submission||08-Jan-2021|
|Date of Acceptance||10-Apr-2021|
|Date of Web Publication||09-Oct-2021|
Dr. Alok Sen
Vitreo-Retina and Uveitis Services, Shri Sadguru Seva Sangh Trust, Sadguru Netra Chikitsalaya, Chitrakoot - 210 204, Madhya Pradesh
Source of Support: None, Conflict of Interest: None
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 21];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. This terminology resurfaced again following the observations of Mehta et al. 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.,,, 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|| |
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|| |
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.
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.,, 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. 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. in their series.
Choroidal involvement in the form of ischemia or inflammation remains the common denominator in the various uveitic pathologies presenting with BLD. 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. 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. 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., 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|| |
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
Conflicts of interest
There are no conflicts of interest.
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