Background: A proof of past streptococcal infection is usually required for the diagnosis of Post streptococcal uveitis, which is achieved by measuring the serum level of anti-streptococcal lysin O titer.
Aim of the work: This study aims to investigate the association between positivity of antistreptolysin O and non-infectious uveitis.    
Patients and Methods: This cross-sectional study included 100 patients diagnosed with noninfectious uveitis at the ophthalmology outpatient clinic of Al-Azhar university hospital, Damietta, Egypt, in cooperation with Mansoura ophthalmic center from November 2022 to April 2023. ASO titer was measured for every patient, and it was considered positive if > 200 IU/ml.
Results: The median [IQR] ASO level was 130.5 [55 – 289.2] IU/ml with a range of [19.9 – 512.2] IU/ml. Its level was higher in the idiopathic, AS, and Arthritis patients than in other study patients, 205 [54.5 – 334.2], 223 [153 – 412], and 225 [40 – 225] respectively. However, this difference between the study groups was not significant statistically [P value > 0.05]. Our study revealed that no significant correlation between the ASO positivity and the degree of visual loss [P value = 0.48]. Correlation analysis between the ASO titer and the type of uveitis, anatomical site of uveitis, and AC score revealed no statistically significant correlation between them and the ASO titer [P = 0.9, 0.1, 0.3 respectively]. Also, we found no significant correlation between the ASO titer and IOP and BCVA.
Conclusion: ASO titer is significantly elevated in noninfectious uveitis, however, our results showed no significant correlation between the ASO and the type of uveitis.