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| CME QUIZ |
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| Year : 2020 | Volume
: 18
| Issue : 2 | Page : 149-150 |
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Understanding the radiological imaging of the eye explant
Sunny Chi Lik Au, Callie Ka Li Ko
Department of Ophthalmology, Tung Wah Eastern Hospital, Hong Kong, China
| Date of Submission | 01-Jan-2020 |
| Date of Decision | 01-Feb-2020 |
| Date of Acceptance | 17-Feb-2020 |
| Date of Web Publication | 17-Apr-2020 |
Correspondence Address:
Dr. Sunny Chi Lik Au
9/F, MO Office, Lo Ka Chow Memorial Ophthalmic Centre, Tung Wah Eastern Hospital, 19 Eastern Hospital Road, Causeway Bay, Hong Kong
China
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/cmi.cmi_1_20
How to cite this article:
Au SC, Ko CK. Understanding the radiological imaging of the eye explant. Curr Med Issues 2020;18:149-50 |
| Case Scenario | |  |
An 81-year-old female with a history of repeated fall at the hostel, suffered from another fall episode with head injury over the table corner. She presented to the hospital with forehead bruises; otherwise, physical examinations were unremarkable without any focal neurological signs. Other than dementia and diabetes mellitus, she suffered from right eye retinal detachment a decade ago, presenting as right eye floaters with inferonasal visual field defect. Surgical repair by Drain-air-cryotherapy-explant (DACE) surgery was done with encircling band No. 240 (FCI Ophthalmics, MA, USA) sutured on the sclera, whereas buckle no. 277 and sleeve no. 70 were placed over the superotemporal region.
Concerning this episode, she did not complain any visual field defect. The eyes were not red, extraocular movement was normal, with no diplopia, and fundoscopy showed normal optic disc and macula, with mild nonproliferative diabetic retinopathy. On X-ray orbit, there were no signs of orbital fracture such as orbital rim discontinuity, pneumo-orbit; teardrop sign (two-dimensional projection of herniated intra-orbital tissue, e.g., fat, over the inferior orbital fracture gap into the maxillary sinus) was absent, and maxillary sinuses were not filled by the fluid level. Computed tomography revealed no intracranial hemorrhages but hyperdensity in collar configuration around the right globe.
| Questions | | |
- What are the types of retinal detachment?
- What are the visual symptoms of retinal detachment?
- How is rhegmatogenous retinal detachment treated?
 View Answer
| Answers | | |
- Retinal detachment can be classified into three types: rhegmatogenous, tractional, and exudative. Rhegmatogenous retinal detachment is the most common type of retinal detachment, which is defined by the presence of defects over the neurosensory retina. The defect can be in the form of retinal U-shaped tear or break or operaculated hole or even retinal dialysis. The most common cause is the posterior vitreous detachment with liquefied vitreous, which is a normal aging process of the eye, usually presents as floaters. Eye trauma and highly myopic eyes are also risk factors. In contrast, tractional retinal detachment is less common and arises from fibroproliferation over the retina in ischemic retinal vascular diseases, such as proliferative diabetic retinopathy, ischemic type of central retinal vein occlusion, or after a penetrating globe trauma. Exudative retinal detachment is rarest and is associated with uveitis, such as Harada disease, posterior scleritis, or ocular malignancy, for example, choroidal melanoma or secondary metastasis. Radiological imaging would be useful if ocular malignancy is suspected
- Visual symptoms depend largely on the location of the retinal detachment. With the eye optical system simulating a convex lens with refractive power of +58 D, contributed by the corneal curvature and the natural lens, the retinal location and its corresponding visual field are vertically and horizontally inverted. Thus, a superotemporal-located retinal detachment would give an inferonasal visual field defect, as in our case presentation before the DACE surgery. If the macula is involved by the retinal detachment, the central vision would be affect. For a mild case, a patient may experience metamorphopsia, whereas extensive retinal detachment might give significant blurring of vision down to the acuity of finger counting or hand movement. Besides, for rhegmatogenous retinal detachment, there may also be floaters and flashes, caused by the vitreous traction over the neurosensory retina
- Rhegmatogenous retinal detachment can be managed by the external drainage surgery,[1] for example, DACE or internal vitrectomy. Before the era of vitrectomy, DACE is a common approach, which is still essential today in the setting without a vitrectomy machine, such as a missionary service. In DACE, retinal breaks were first identified, and the subretinal fluid was drained via a needle puncturing the sclera. Gas was then injected before the application of cryotherapy to the detached site. Explant was then kept on the sclera to indent the globe hoping to appose the detached retina and release the vitreous traction.[2] About 60%–70% of the retinal breaks are located at superotemporal quadrant,[3] as in our case. Encircling band is indicated for multiple retinal breaks over different quadrants or with a possible missed break.[1] It comes in a silicone strip and requires a sleeve to keep the tension around the globe,[2] thus appearing as a hyperdense collar around the globe on computed tomography. The silicone tire added over to the encircling band aims to provide a greater surface area of indentation at the diseased site, such as area clustered with multiple breaks, and to provide better support for the apposition of the detached retina. The tire and sleeve over the encircling band contributes to the stepping appearance of the hyperdense collar around the globe on computed tomography [Figure 1].
 | Figure 1: Computed tomography of the head showed hyperdense collar-like explant over the right globe, representing the encircling buckle. The coronal cut over the globe (a) clearly demonstrated the stepping appearance of the hyperdensity over the orbital superotemporal quadrant, illustrating the position of the sleeve and tire over the encircling buckle. The whole explant complex is more thoroughly seen on three-dimensional reconstruction image (b).
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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.{Figure 1}
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 | | |
| 1. | Banaee T, Hosseini SM, Helmi T, Ghooshkhanei H. Encircling narrow band versus buckle for retinal detachments with intrabasal or unseen retinal breaks. J Ophthalmic Vis Res 2015;10:55-9.  [ PUBMED] [Full text] |
| 2. | Shanmugam PM, Ramanjulu R, Mishra KC, Sagar P. Novel techniques in scleral buckling. Indian J Ophthalmol 2018;66:909-15. [ PUBMED] [Full text] |
| 3. | Shunmugam M, Shah AN, Hysi PG, Williamson TH. The pattern and distribution of retinal breaks in eyes with rhegmatogenous retinal detachment. Am J Ophthalmol 2014;157:221-60. |
[Figure 1]
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