Introduction: Playing online games has become a most popular leisure activity in many parts of the world, which may impact people's health as a result of excessive gaming, most commonly among students. Some computer-related and vision-related researches have measured the physical and ocular effects and binocular vision separately. India has second largest number of users of cell phones. In India, few studies conducted to assess its impact on health. Presently, the incidence of internet gaming disorder among the adolescent group was between 1.3% to 19.9%. Aim: To determine the effectiveness of self-instructional module on knowledge regarding vision hazards while playing online games among junior college students. Materials and Methods: A pre-experimental pre-test, post-test research design was used to conduct this study. The study was conducted during September 2019 to February 2020 and the setting was selected in the New English junior college, Wardha (Maharashtra) after getting ethical permission. (Ref. no: DMIMS (DU)/IEC/Sept-2019/8494). Purposive sampling was the sampling method used to collect data from junior college students (11th standard students) on the basis of structured knowledge questionnaire. After collecting pre-test data, self-instructional module was given for intervention of vision hazards while playing online games to junior college students. Seven days were provided to the samples for utilising self-instructional module which was organised for 45-50 minutes. Post-test information was gathered after seven days from the day of intervention. The data were described by frequency, percentage and t-test was used to describe the difference between pre-test and post-test knowledge score. Chi-square test was also used to find out the association between knowledge of junior college students regarding vision hazards while playing online games and selected demographic variables. Results: There was a significant difference between pre-test and post-test knowledge scores interpreted that self-instructional module on knowledge regarding vision hazards while playing online games among junior college students were effective. Mean value of pre-test was 7.82 and post-test was 15.62 and standard deviation values of pre-test was ±1.88 and post-test was ±0.58. The calculated t-value was 39 and p-value was 0.0001. Conclusion: The study was effective because the post-test knowledge score improved than the pre-test knowledge score. So, the self-instructional module has proved to improve junior college student’s knowledge regarding vision hazards while playing online games.