Floating islands-ultra-widefield imaging of rapid silicone oil emulsification.

Introduction

Ultra-widefield(UWF) retinal imaging helps in documentation of large retinal area in a single capture and allows evaluation of serial changes. We document unusually rapid silicone oil(SO) emulsification at 3 weeks in a young female following surgery for subluxated cataract and rhegmatogenous retinal detachment. Serial UWF imaging revealed free-floating agglomerate of emulsified SO droplets over pre-retinal surface posterior to intact silicone oil bubble.

Image Description

A 22-year-old female presented with diminished vision in the left eye (OS) for 3 months. Best-corrected visual acuity in the right eye (OD) was 20/20 and in OS was counting fingers 1 m. Slit-lamp examination revealed inferotemporal subluxated cataract in OS. Fundus examination of OS revealed rhegmatogenous retinal detachment extending from 2–10 o’clock hours with retinal tear at 4 o’ clock. Evaluation in OD was unremarkable. She underwent 23G pars plana lensectomy, vitrectomy, and silicone oil (1300 Cst) injection in OS. At 3 weeks postoperatively, eye was quiet. Anterior chamber examination revealed aphakia and mobile silicone oil droplets in aqueous with inverse hypopyon. Fundus assessment showed reattached retina. There were clusters of emulsified oil droplets posterior to large silicone oil bubble (LSOB) in upper half mimicking “appearance of islands” on the global map [Figure 1a]. At 6 weeks, fundus showed attached retina and increase in the number of clusters of emulsified oil droplets with change in their location [Figure 1b]. This mimicked aerial view of “floating islands.” Considering rapid progression of silicone oil emulsification, early silicone oil removal was performed. At 8 weeks, best-corrected visual acuity in OS was 20/250 with attached retina.

Figure 1

(a) Ultra-widefield image of the left eye fundus 3 weeks postvitrectomy showing clusters of emulsified silicone oil droplets, mimicking aerial view of islands on the global map. (b) Ultra-widefield image at 6 weeks showing rapid increase in the number and size of clusters with change in their location, mimicking aerial view of floating islands

Discussion

Current ultra-widefield (UWF) retinal imaging system (Optos PLC, Dunfermline, United Kingdom) provides around 200° (82%) of fundus image in the single capture. It represents a three-dimensional image on a two-dimensional flat surface (Mercator projection) with a consistent geometry and accurate anatomic features of the retina.[1] In the presence of LSOB occupying the vitreous cavity, the posterior retinal surface is covered by only a thin layer of aqueous.[2] Emulsified oil droplets posterior to LSOB are trapped as clusters in this thin layer, predominantly in the upper half as seen in our case probably due to lower specific gravity.[3] Reduced intraocular fluid current in the presence of LSOB might have contributed to this island like appearance on UWF imaging. An increase in the number and size of clusters noted in subsequent 3 weeks was most likely due to rapid emulsification as this was associated with increase in hyperoleon. Moreover, change in position of clusters of droplets was also observed posterior to LSOB on UWF image, which could be explained by mobility of silicone oil droplets in the aqueous layer.

Possible reasons for rapid emulsification seen in this eye could be: (1) Use of low viscosity silicone oil, (2) young patient with congenital subluxation of cataractous lens, (3) absence of posterior capsule and zonules postlensectomy and (4) possible residual layer of cortical vitreous.[4]

A floating island consists of floating aquatic plants, mud, and peat. It has a tendency to move and can be many hectares in size.[5] Clusters of emulsified oil droplets on serial two-dimensional UWF fundus images seen in our case, thus mimicked aerial view (two-dimensional image) of floating islands. This was possible due to ability of UWF imaging system to capture 200° view of the retina which is not possible otherwise.

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.