Background: many of autoimmune diseases associated with ophthalmological complication, such as Peripheral ulcerative keratitis. Objective: to evaluate the potential changes in the peripheral corneal thickness in selected rheumatic autoimmune diseases. Patients and Methods: a case control study was been held in Al-Azhar University Hospitals on 80 eyes for 40 patients and subjects. The patients and subjects was been examined by Pentacam examination. Results: as regard peripheral corneal thickness, the mean peripheral thickness of RA patients was 668.6 ± 32.1 micron, the mean peripheral thickness of SLE patients was 667.5 ± 34.8 micron, the mean peripheral thickness of SNA patients was 637.8 ± 86.7 micron and the mean peripheral thickness of control patients was 681.2 ± 12.8 micron (p-value = 0.045). Conclusion: the peripheral corneal thickness was thinner in autoimmune patients than in normal subjects.