Alessandro Invernizzi, Peter McCluskey
Purpose: To compare Optical Coherence Tomogra- phy (OCT) features of active necrotizing infectious retinitis (NIR) due to toxoplasmosis or Herpes viruses and to determine distinctive OCT signs for these two causes of infectious retinitis.
Methods: OCT images from patients diagnosed with active NIR due to Varicella Zoster Virus (VZV), Herpes Simplex Virus (HSV), Cytomegalovirus (CMV), and Toxoplasmosis (TOXO) were reviewed. Prevalence of OCT ftndings previously described in TOXO chorioretinitis was compared between TOXO vs viral-infected population. New OCT ftndings were also recorded and compared. Retinal and cho- roidal thickness measured at the site of the active lesion on OCT scans were compared among the 2 groups.
Results: 10 eyes with TOXO chorioretinitis and
13 eyes with viral necrotizing retinitis (9 CMV, 4 VZV) were analysed. All eyes showed full thick- ness hyperre?ectivity and disruption of the retina and a variable degree of vitritis. Among previously described OCT ftndings hyper-re?ective oval deposits and hypo-re?ectivity of the choroid had a higher prevalence in TOXO (p=0.018 and p<0.0001 respectively). Among the newly observed signs, clots of cells along the posterior hyaloid, retrohya- loid hyper-re?ective spots and disruption of choro- dial architecture were more frequent in TOXO (all p<0.01). Intraretinal edema and hyper-re?ective vertical strips within the outer nuclear layer resulted suggestive for viral etiology (both p=0.045). Retinal thickness did not differ among the two groups. Cho- roidal thickness was signiftcantly higher in TOXO (p=0.01). Conclusions: The diagnosis of necrotizing infectious retinitis is largely based on clinical and laboratory ftndings. OCT changes may be useful in differentiat- ing different causes of NIR.