BACKGROUND: Various imaging modalities play a role in diagnosing parasitic infections of the eye. We describe the spectral domain optical coherence tomography (SD-OCT) findings of an intravitreal parasite with subsequent evaluation by light microscopy. FINDINGS: This is a case report of a 37-year-old Ecuadorian man who presented with uveitic glaucoma and a new floater in his left eye for 1 week’s duration. Full ophthalmic examination revealed an intravitreal parasite. Color fundus photography, fluorescein angiography (FA), ocular ultrasonography (US), and SD-OCT were performed. The parasite was removed via 23-gauge pars plana vitrectomy and sent to pathology for evaluation. Color fundus photography and ocular ultrasonography demonstrated an elongated foreign body within the vitreous above the retina. FA demonstrated minimal vascular changes in the vicinity of the parasite. SD-OCT was utilized to visualize the parasite and to create a three-dimensional (3D) image. The parasite was determined to be most consistent with Gnathostoma spp. by morphologic analysis. CONCLUSIONS: This is the first reported case of SD-OCT of an intravitreal parasite with corresponding evaluation by pathology. SD-OCT allows non-invasive, high-resolution visualization and 3D reconstruction of parasitic anatomy which may help establish tomographic criteria for species identification. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12348-015-0064-x) contains supplementary material, which is available to authorized users

A Khatibi

A Lago do

A Masudi

AH Gomes

AR Forman

C Behr

CR Fitzgerald

DN Sujata

E Ahmed

GS Pillai

H Bhattacharjee

H Morsy

J Biswas

JDM Gass

JH Yang

JM Rusnak

K Sasana

M Bhende

M Funata

ME Bathrick

MS Kearney

SK Basak

T Higashide

T Suzuki

Journal of Ophthalmic Inflammation and Infection

PubMed

Aziz A. Khanifar

Michael J. Espiritu

Jane S. Myung

Grant D. Aaker

Audrey N. Schuetz

Donald J. D’Amico

R. V. Paul Chan

Crossref

BRIEF REPORT Open AccessThree-dimensional spectral domain opticalcoherence tomography and lightmicroscopy of an intravitreal parasiteAziz A. Khanifar1, Michael J. Espiritu1, Jane S. Myung1, Grant D. Aaker1, Audrey N. Schuetz2, Donald J. D’Amico1and R. V. Paul Chan1,3*AbstractBackground: Various imaging modalities play a role in diagnosing parasitic infections of the eye. We describe thespectral domain optical coherence tomography (SD-OCT) findings of an intravitreal parasite with subsequentevaluation by light microscopy.Findings: This is a case report of a 37-year-old Ecuadorian man who presented with uveitic glaucoma and a newfloater in his left eye for 1 week’s duration. Full ophthalmic examination revealed an intravitreal parasite. Color fundusphotography, fluorescein angiography (FA), ocular ultrasonography (US), and SD-OCT were performed. The parasitewas removed via 23-gauge pars plana vitrectomy and sent to pathology for evaluation.Color fundus photography and ocular ultrasonography demonstrated an elongated foreign body within the vitreousabove the retina. FA demonstrated minimal vascular changes in the vicinity of the parasite. SD-OCT was utilized tovisualize the parasite and to create a three-dimensional (3D) image. The parasite was determined to be most consistentwith Gnathostoma spp. by morphologic analysis.Conclusions: This is the first reported case of SD-OCT of an intravitreal parasite with corresponding evaluation bypathology. SD-OCT allows non-invasive, high-resolution visualization and 3D reconstruction of parasitic anatomy whichmay help establish tomographic criteria for species identification.Keywords: Gnathostomiasis, Gnathostoma, Ophthalmomyiasis, Optical coherence tomography, Parasitic infection,Retinal imagingFindingsIntroductionIntraocular parasites are uncommon occurrences inthe USA. Diagnosis is dependent on reliable historyof ingested foods, geographic location, season, anddirect visualization of the parasite with ophthalmos-copy. Various imaging modalities have also been ap-plied in the study of intraocular parasites such asfluorescein angiography. Ultrasound biomicroscopyhas been used to localize larvae when not seen on di-lated fundus examination [1], and scanning electronmicroscopy has aided morphological study for speciesdetermination [2, 3].While optical coherence tomography (OCT) has beenutilized in visualizing tracks of nonspecific cutaneous larvamigrans through the epidermis [4], its capabilities have yetto be explored with regard to complete visualization of anintraocular helminthic infection. We report a case in whichspectral domain optical coherence tomography (SD-OCT)imaging of an intravitreal parasite was performed. The clin-ical presentation and pathological findings are most consist-ent with Gnathostoma spp.Case reportA 37-year-old Ecuadorian immigrant presented to theNew York-Presbyterian Hospital Emergency Depart-ment with a 3-day history of redness, pain, and hazy* Correspondence: rvpchan@uic.edu1Department of Ophthalmology, Weill Cornell Medical College, New York,NY, USA3Department of Ophthalmology and Visual Sciences, Illinois Eye and EarInfirmary, University of Illinois at Chicago, Chicago, IL, USAFull list of author information is available at the end of the article© 2015 Khanifar et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, andreproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link tothe Creative Commons license, and indicate if changes were made.Khanifar et al. Journal of Ophthalmic Inflammation and Infection  (2015) 5:33 DOI 10.1186/s12348-015-0064-xvision in his left eye. He denied flashes, photophobia,or discharge in either eye. He had no complaints inhis right eye.Two weeks prior to presentation, he experienced fe-vers, nasal congestion, and muscle aches, which spon-taneously resolved. He also admitted to recentlyseeing a curved floater in his left eye. His past med-ical history was significant only for Bell’s palsy on theleft in 2004, which had resolved spontaneously with-out ocular complications. His last tuberculin skin testwas 3 years prior to presentation and was negative.He denied any risk factors for HIV. His past socialhistory revealed that he immigrated to the USA fromEcuador 13 years ago and has not been back toEcuador for 9 years. He denied any other travel, farmwork, or extended contact with animals. The patientworked in a local restaurant as a cook, handling rawbeef, pork, poultry, and both saltwater and freshwaterfish with his bare hands. He reported that his dutiesinclude preparing the tuna tartar, and he usually eatsany leftover food.On examination, his visual acuity was 20/20 in botheyes with pinhole. Intraocular pressure (IOP) was 12and 35 mm Hg in his right and left eyes, respectively.Pupils, motility, confrontational visual fields, and ex-ternal exam were within normal limits bilaterally. Slitlamp biomicroscopy and dilated fundus examinationwere normal for the right eye. In the left eye, theconjunctiva and sclera were quiet, and the cornea hadmicrocystic edema and fine keratic precipitates. Cellswere present in the anterior chamber, but there wasno hypopyon. The iris and lens were normal. Dilatedfundus exam revealed a peripheral operculated holein the left eye and a single linear object measuringapproximately 3 mm in length floating in the nasalvitreous. The object appeared to have a white discfollowed by a whitening of the body on one end anda white pointed tip preceded by a reddish brown col-oration of the body at the other end (Fig. 1). Novitritis, papillitis, vasculitis, retinitis, and other retinalbreaks or detachments were noted. Ultra-widefieldfluorescein angiography demonstrated mild vascularsheathing in the region where the parasite was origin-ally seen (Fig. 2). Ocular ultrasonography verified thatthe object was not in contact with the retinal surface (Fig. 3).Fig. 1 a Wide-angle color fundus photograph of the patient’s left eye demonstrating the parasite (white oval) within the vitreous and nasal to theoptic disc. b Higher magnification color photograph of the intravitreal parasiteFig. 2 Wide-angle fluorescein angiogram demonstrating vascularsheathing (white arrow) in the region where the parasite wasinitially visualizedKhanifar et al. Journal of Ophthalmic Inflammation and Infection  (2015) 5:33 Page 2 of 6Using the Topcon 3D OCT-1000 (Topcon MedicalSystems, Paramus, NJ), the intravitreal object was im-aged (Fig. 4a, b and Additional file 1: Video 1).Three-dimensional (3D) reconstructions using theOCT B-scans were also created (Fig. 5a, b and Add-itional file 2: Video 2). Review of the scans demon-strated a tubular structure with a central lumenoverlying the nasal retina. Superiorly, the lumencontained hyper-reflective material (Fig. 4a), whereasthe inferior lumen was hypo-reflective (Fig. 4b).Further diagnostic evaluation of the patient revealedperipheral eosinophilia, and magnetic resonance im-aging of the brain was negative for cerebral larvae.Based on its appearance, gnathostomiasis was high onthe differential diagnosis. A 23-gauge pars plana vi-trectomy with removal of the foreign body was per-formed. Intraoperatively, the presumed worm wasnoted to be associated with superficial retinal hemor-rhages and resist aspiration. The worm was eventuallyaspirated with a vitreous cutter using aspiration only.The specimen, within the tip of the vitreous cutter,was sent for microscopic evaluation by the Depart-ment of Pathology and Laboratory Medicine at NewYork-Presbyterian Hospital. The patient was dis-charged on oral ivermectin and recovered well.Macroscopically, the single larva was light red-brown in color and 3 mm in length when viewedunder a dissecting microscope (Fig. 6). Only a portionof the worm was available for examination after re-moval from the vitreous cutter, with a portion of thecuticle removed. Through examination of theremaining worm, including the probable gastrointes-tinal tract and the remnant of the anterior portion ofthe worm, a differential diagnosis was generated.Based on the size of the larva and the minute spinespresent on the cuticular armature of the head bulbon the anterior portion of the worm (Fig. 7),Gnathostoma spp. was the most likely diagnosis. TheFig. 4 Spectral domain optical coherence tomography (SD-OCT) images of the parasite demonstrating two concentric circles within the vitreousabove the retina. Note that the inner circle is hyper-reflective superiorly (top image) and hypo-reflective inferiorly (bottom image)Fig. 3 Ocular ultrasonography demonstrating the parasite (white arrow)within the vitreous. Note that the parasite is not in contact withthe retinaKhanifar et al. Journal of Ophthalmic Inflammation and Infection  (2015) 5:33 Page 3 of 6differential included bot fly larva or Thelazia spp.based on ocular localization, but the organism shapeand size were not consistent with those organisms.DiscussionTo our knowledge, this is the first reported case ofintravitreal 3D SD-OCT imaging of a parasite in vivoand subsequent evaluation with light microscopy.Other investigators have utilized OCT to followcomplications of parasitic infestation, but imaging ofthe actual parasite has rarely been reported [5–11].Gnathostomiasis is a rare parasitic infection that canaffect multiple organ systems, including the eye. Thiszoonosis results from accidental ingestion of immatureGnathostoma larvae, a type of roundworm endemic toSoutheast Asia and Latin America. The most commonclinical presentation is dermatological—a cutaneousFig. 6 Light microscopy photograph of the parasite removed fromthe patient’s vitreous cavity. The cuticle has been partially removedFig. 5 a Three-dimensional reconstruction of spectral domain optical coherence tomography (SD-OCT) images of the intravitreal parasite. b Additionalview of SD-OCT image from different anglesFig. 7 Higher magnification photograph of the rostral portion of theparasite demonstrating minute cuticular spines encircling the cuticulararmature of the head bulbKhanifar et al. Journal of Ophthalmic Inflammation and Infection  (2015) 5:33 Page 4 of 6larva migrans [2]. However, intraocular gnathostomiasisis uncommon and can be localized to the anterior seg-ment, retina, and vitreous cavity [12–19].Myiasis is another parasitic infection that can affectthe skin and the eye (ophthalmomyiasis). The causativeorganism is the immature larva of any fly of the orderDiptera. Invasion of the globe is classified as ophthalmo-myiasis interna anterior/posterior [20]. The clinical pres-entation of ophthalmomyiasis interna posterior (OIP) isvery similar to that of intraocular gnathostomiasis, includ-ing uveitis (with or without eosinophilia) and self-limitingperiorbital swelling [21]. For cases of OIP in which thelarva is located within the subretinal space, photocoagula-tion may be used with minimal or no resultant inflamma-tion [22, 23]. The subretinal pigmented tracks formedfrom larval migration within the subretinal space are path-ognomonic for OIP [24].Regarding the intraocular parasite of this patient, theSD-OCT findings are consistent with the findings onophthalmoscopy. The internal reflectivity of the superiorsegments varies compared to that of the inferior segments.The hyper-reflectivity superiorly likely corresponds to ahyper-cellular esophagus represented as whitening grossly,and the hypo-reflectivity inferiorly corresponds to a rela-tively hypo-cellular intestinal tract represented as reddishbrown coloration grossly. Closer observation of the infer-ior scans of the parasite reveals hyper-reflective lines con-necting the outer lumen with the inner lumen. Thesehyper-reflective lines may represent lateral chords, andthis configuration may be more suggestive of gnathosto-miasis [25].The high-resolution imaging of the worm and theacquisition of multiple images aligned along the bodyof the worm would be extremely difficult if not im-possible with time-domain OCT.SD-OCT with its high-speed scanning not only al-lows visualization of microscopic detail in vivo, butalso allows volumetric, three-dimensional imaging.The Topcon 3D OCT-1000 (Topcon Medical Systems,Paramus, NJ) was able to render a three-dimensionalrepresentation of the worm in the vitreous. While pa-tient history and visualization of the worm are helpfulin diagnosing intraocular parasites, microscopic diag-nosis is more definitive. SD-OCT may play an ad-junctive role in identifying intraocular parasiticspecies prior to surgical removal and should be con-sidered as part of the diagnostic imaging evaluation.Additional filesAdditional file 1: Video 1. SD-OCT video demonstrating two concentriccircles within the vitreous above the retina. (WMV 6952 kb)Additional file 2: Video 2. Three-dimensional SD-OCT videodemonstrating the parasite within the vitreous above the retina.(WMV 6430 kb)Abbreviations3D: three-dimensional; OIP: ophthalmomyiasis interna posterior; SD-OCT: spectral domain optical coherence tomography.Competing interestsThe authors declare that they have no competing interests.Authors’ contributionsAll authors have (1) made substantial contributions to the conception anddesign, or acquisition of data, or analysis and interpretation of data; (2) havebeen involved in drafting the manuscript or revising it critically for importantintellectual content; (3) have given final approval of the version to bepublished; and (4) agree to be accountable for all aspects of the work inensuring that questions related to the accuracy or integrity of any part ofthe work are appropriately investigated and resolved. AK, JM, and RVPCparticipated in the care of the patient reported and acquired all relevantinformation that related to this case report. MJE, AK, GDA, JM, RVPC, DJD,and ANS participated in the manuscript preparation. MJE, AK, GDA, and RVPCparticipated in the image collection and data acquisition. ANS performed thepathology and interpretation.Authors’ informationDJD is Professor and Chairman of Ophthalmology at Weill Cornell MedicalCollege. ANS is Associate Professor of Pathology and Laboratory Medicine,and Associate Director of Clinical Microbiology Laboratory Services at WeillCornell Medical College. RVPC is Professor and Vice Chair of the Departmentof Ophthalmology and Visual Sciences at the University of Illinois at Chicago.AcknowledgementsSupport was provided by the St. Giles Foundation (RVPC), DepartmentalGrant from Research to Prevent Blindness (RVPC, AAK, JSM, GDA, MJE, DJD).Author details1Department of Ophthalmology, Weill Cornell Medical College, New York,NY, USA. 2Department of Pathology and Laboratory Medicine, Weill CornellMedical College, New York, NY, USA. 3Department of Ophthalmology andVisual Sciences, Illinois Eye and Ear Infirmary, University of Illinois at Chicago,Chicago, IL, USA.Received: 27 August 2015 Accepted: 5 November 2015References1. Bhende M, Biswas J, Gopal L (2005) Ultrasound biomicroscopy in thediagnosis and management of intraocular gnathostomiasis. Am JOphthalmol 140:140–1422. Rusnak JM, Lucey DR (1993) Clinical gnathostomiasis: case report andreview of the English-language literature. Clin Infect Dis 16:33–503. 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Accessed on August 7,2015.Submit your manuscript to a journal and beneﬁ t from:7 Convenient online submission7 Rigorous peer review7 Immediate publication on acceptance7 Open access: articles freely available online7 High visibility within the ﬁ eld7 Retaining the copyright to your article    Submit your next manuscript at 7 springeropen.comKhanifar et al. Journal of Ophthalmic Inflammation and Infection  (2015) 5:33 Page 6 of 6

Three-dimensional spectral domain optical coherence tomography and light microscopy of an intravitreal parasite

Background: Various imaging modalities play a role in diagnosing parasitic infections of the eye. We describe the spectral domain optical coherence tomography (SD-OCT) findings of an intravitreal parasite with subsequent evaluation by light microscopy. Findings: This is a case report of a 37-year-old Ecuadorian man who presented with uveitic glaucoma and a new floater in his left eye for 1 week’s duration. Full ophthalmic examination revealed an intravitreal parasite. Color fundus photography, fluorescein angiography (FA), ocular ultrasonography (US), and SD-OCT were performed. The parasite was removed via 23-gauge pars plana vitrectomy and sent to pathology for evaluation. Color fundus photography and ocular ultrasonography demonstrated an elongated foreign body within the vitreous above the retina. FA demonstrated minimal vascular changes in the vicinity of the parasite. SD-OCT was utilized to visualize the parasite and to create a three-dimensional (3D) image. The parasite was determined to be most consistent with Gnathostoma spp. by morphologic analysis. Conclusions: This is the first reported case of SD-OCT of an intravitreal parasite with corresponding evaluation by pathology. SD-OCT allows non-invasive, high-resolution visualization and 3D reconstruction of parasitic anatomy which may help establish tomographic criteria for species identification

A. A. Khanifar (7928036)

M. J. Espiritu (7928039)

J. S. Myung (7928042)

G. D. Aaker (7928045)

A. N. Schuetz (7928048)

D. J. D’Amico (7928051)

R. V. P. Chan (7928054)

University of Illinois at Chicago: UIC INDIGO (INtellectual property in DIGital form available online in an Open environment)

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Three-dimensional spectral domain optical coherence tomography and light microscopy of an intravitreal parasite

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