Serial ultra wide field imaging for following up acute retinal necrosis cases

Abstract

We describe two cases of acute retinal necrosis (ARN) in a post renal transplant diabetic patient and a pregnant female in the first trimester. Serial ultra wide field imaging (UWFI) with comprehensive ocular examination was done to monitor the progression of the disease. All the cases responded favorably with intravenous followed by oral acyclovir, which was captured with UWFI. UWFI provides objective proof of response to therapy in ARN. UWFI may also improve patient education and counseling for this peripheral retinal disorder.

Introduction

Ultra-wide field imaging (UWFI) and UWF angiography (UWFA, Optos Inc, Marlborough, Ma, USA) uses scanning laser technology to give single image of up to 82% or 200° of the retina. UWFI uses the ellipsoid mirror with two focal points. The laser of the UWFI is directed through one of the focal points while second focal point is located inside the patient's eye capturing peripheral retina even through small pupil.[1] UWFI and UWFA have been reported to document disease severity, progression, and response to therapy of intermediate and posterior uveitis. It may significantly alter management in retinal vasculitis. It has been shown to pick up more retinal vascular pathology, in both the periphery and the posterior pole in uveitis, and more area of cytomegalo viral retinitis when compared with examination and standard fluorescein angiography. Acute retinal necrosis (ARN) presents with peripheral confluent retinitis. Due to peripheral circumferential spread of the disease clinical documentation is difficult with the available fundus cameras which have limited field capturing capacity of 30° and 50° and various montaging techniques could portray up to maximum of 140°.[1] We describe utility of this wide field imaging in the management of ARN.

Case Reports

Case 1

A 37-year-old male with insulin-dependent diabetes mellitus who underwent renal transplantation for chronic kidney disease 1 year back, presented with redness in either eye. Since the patient was on immunosuppressants, he developed systemic varicella with ocular involvement in the form of ARN. His human immunodeficiency virus (HIV) serology was negative. On examination, visual acuity was 6/18 in right eye and 6/60 in left eye. Anterior chamber cells were 3+ in either eye with posterior synechiae and small nondilating pupils. He had healed retinitis in left eye [Figure 1a] and posterior subcapsular cataract [Figure 1b]. Right eye had peripheral multifocal active retinitis in right eye [Figure 2a]. He was managed by intravenous acyclovir 13 mg/kg thrice daily for 7 days, followed by oral acyclovir 800 mg five times in consultation with nephrologists in conjunction with topical steroids and cycloplegics. Active retinitis started healing within 7 days [Figure 2b] with complete resolution within 30 days [Figure 2c].

Figure 1.

(a) Healed retinitis in left eye of case 1 with pigmentation and only island of the posterior retina remaining with arteriolar involvement (b) Small pupil with extensive posterior synechia with posterior subcapsular cataract

Figure 2.

(a) At presentation multifocal peripheral active retinitis patches are seen in the right eye of case 1 (b) At 7th day of follow-up retinitis has started responding (c) At 30 days the retinitis has resolved with pigmentary changes, arteriolar attenuation and disc pallor

Case 2

A 23-year-old pregnant lady in 10^th week of gestation presented to us with diminution of vision in left eye for 1 week. On examination, visual acuity was 6/6 in right eye and hand movement close to face with an accurate projection of rays in left eye. The right eye was normal. Left eye showed 2+ anterior chamber cells, clear lens and retrolental cells. Left eye showed disc edema with extensive 360° confluent active retinal necrosis [Figure 3a]. She started developing varicella zoster lesions on the face for 1 week before the presentation. Her serology for HIV was negative; however, antivaricella zoster immunoglobulin M (IgM) was positive. Obstetrics clearance and written consent from the patient was obtained for intravenous acyclovir explaining category B status of acyclovir. Though retinitis started healing by 6^th day [Figure 3b] vision did not improve as disc pallor and arteriolar attenuation ensued [Figure 3c].

Figure 3.

(a) Left eye of case 2 shows 360° confluent peripheral retinal necrosis with disc edema (b) On 6th day the size of whitened retina has decreased (c) At 10th day arteriolar attenuation and disc pallor ensued

Discussion

In both the above described patients UWFI was able to detect and clearly demonstrate the extent and activity of the disease along with the response to therapy even in nondilating small pupil, cataract (first case) and vitritis. ARN is a known complication of varicella zoster virus infection in immunosuppressed kidney transplanted patients. ARN has also been reported in pregnant women after infection with both varicella zoster virus[2] and herpes simplex virus type 1.[3] It has been reported in 23^rd week of gestation,[4] and in the third trimester.[5] In our second case, the pregnant lady developed ARN in late first trimester, which has not been reported earlier. Patient education and counseling about the disease severity and response may become easier with UWFI. Moreover, it can be helpful to assess the response to therapy as well as early detection of necrotic breaks in the periphery that often lead to retinal detachment in these patients. However, upper lid lashes may sometimes obscure details of inferior retinal periphery in UWFI. UWFI, thus, is becoming the indispensable modality in the management of ARN in our practice.