Purpose This study aimed to identify the various clinical characteristics and ocular imaging features of ocular toxoplasmosis (OT) in HIV patients.

Methods Observational retrospective study of 52 eyes of 38 HIV patients with OT.

Results 68% of patients were male. 53.8% of eyes had keratic precipitates, anterior chamber cells were seen in 61.5%. 57.69% (n=30) eyes had de novo presentation of retinitis and 42.3% (n=22) of eyes had a retinochoroidal scar at presentation. Bilateral presentation was seen in 37% (n=14). Unifocal retinitis was noted in 38.4% (n=20) and 61.5% of eyes had multifocal (multizonal) retinitis (n=32). The most common multizonal involvement was noted in combined zone 1+2(n=14, 26.9%). The average horizontal and vertical measurements retinitis was 8.35 mm and 7.48 mm, respectively. The average area of retinitis was 66.2 mm². Localised posterior vitreous detachment was seen in 83% of eyes and posterior hyaloid precipitates were noted in (n=7,39%) of eyes. Retinitis without retinal pigment epithelium elevation occurred in 88.8% of cases, compared with retinitis with retinal pigment epithelium elevation seen in 44.4% of eyes. 50% of eyes had thickened choroid beneath the retinitis lesion. Other unique signs of optical coherence tomography (OCT) noted were angular signs of Henle fibre layer hyper-reflectivity sign (n=1), halo lesions with central hypo (n=3) and choroidal excavation (n=1).

Conclusions OT in HIV patients presents with large, bilateral, multifocal retinitis, generally devoid of haemorrhages and can rarely have central clearing. These lesions may present with or without a previous retinochoroidal scar. These lesions have horizontal spread and may not always have thickened choroid on OCT.