Acers 1964.

Methods	Participants allocated by a "random listing" It was not clear whether 1 or both eyes were included
Participants	Participants (n = 20) residing in Baltimore, USA with active retinitis, positive toxoplasma skin test and antibody test (dye test), and no other cause of retinitis. Mean age 32.9 years (treatment), 30.9 years (controls) (age range 18 to 49 years)
Interventions	Pyrimethamine (200 mg/day 1, 100 mg/day 2, 50 mg/day on days 3 to 15, 25 mg/day on days 16 to 56); trisulfapyrimidine 2 g/day for 8 weeks; prednisolone (40 mg/day on days 1 to 7, 20 mg/day on days 8 to 56) versus lactose capsules and prednisolone as above
Outcomes	Change between baseline and end of treatment at 8 weeks in: visual acuity intraocular inflammation (classified as "improved versus same or worse" based on visual acuity, media and lesion appearances) adverse events (nausea, loss of appetite, rash, arthralgia, stopped treatment due to low platelet count) Time to quiescence of lesion Recurrence of lesions during the 2 years of the study (length and completeness of follow‐up unclear) Outcomes assessed masked to treatment allocation at 8 weeks but not thereafter. Follow‐up complete at 8 weeks but not stated for the 2 years of the study
Notes	Date study conducted: Not reported Funding source: Training Grant No. 2B‐5217, from the National Institute of Neurological Diseases and Blindness, US Public Health Service Declaration of interest: not reported Trial registration: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random listing
Allocation concealment (selection bias)	Unclear risk	No relevant statement
Blinding of participants and personnel (performance bias) All outcomes	Low risk	A lactose capsule was used as a placebo: “placed in identical bottles.” Masking of ocular outcomes from clinical data on side effects
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Separate, independent assessors were used for clinical signs and for ophthalmic examination. The ophthalmic assessor “did not inquire about, or obtain, any subjective information or laboratory data.”
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Complete follow‐up for 8 weeks, but this would not be adequate for detecting recurrence. Completeness of follow‐up over the entire 2‐year study period unclear
Selective reporting (reporting bias)	Low risk	Recurrence was a secondary outcome, although no details are given about the completeness of follow‐up for this outcome