Purpose: Idiopathic nephrotic syndrome (NS) often necessitates prolonged or repeated corticosteroid treatment, which increases the risk for steroid-induced posterior subcapsular cataract (SI-PSC). Previous research on its burden remains limited. Here, we aimed to determine the prevalence and predictive risk factors of SI-PSC in children with NS. Methods: This cross-sectional study was conducted in the Pediatric Nephrology Department of The Kidney Centre, Karachi, Pakistan, from October 2023 to October 2025. The study included 150 children with NS, aged 2–16 years, who had received oral prednisolone for more than 6 months. Demographic and clinical information were collected through caregiver interviews and medical record review. All participants underwent a detailed slit-lamp examination by the same ophthalmologist. Associations between cataract formation and demographic or treatment-related variables were analyzed statistically. A P-value of ≤0.05 was considered significant. Results: Cataracts were detected in 23 children (15.3%). Most patients had early lenticular changes, but only two required surgical intervention. Other ocular abnormalities were uncommon (4.7%). Cataracts occurred more frequently in males and in children younger than 10 years. Cumulative corticosteroid doses were nearly identical in patients with and without cataracts. Children with frequently relapsing NS accounted for the highest proportion of those with SI-PSC. Systemic hypertension was the adverse effect most strongly associated with cataract development. Conclusions SI-PSC is a notable complication in children receiving long-term corticosteroid therapy. Our findings underscore the importance of routine ophthalmologic screening. Individual susceptibility, including potential genetic factors, might play a role in cataract development and warrant further investigation.