Out of 55 cases of episcleritis, only five cases had coexistent connective tissue disease, while 14 such cases were found among 31 cases of scleritis. Rheumatoid arthritis was the commonest associated disease in each case. The patients suffering from scleritis had attacks which lasted longer than the patients suffering from episcleritis. The palpebral area was affected more often in scleritis than in episcleritis, and all the patients suffering from scleritis and rheumatoid arthritis had scleral thinning which always affected the superior sclera. The majority of cases of episcleritis had single attacks affecting the interpalpebral area and lasting less than three months, suggesting that minor trauma may be a factor in their causation.
Lyne AJ, Pitkeathley DA. Episcleritis and ScleritisAssociation With Connective Tissue Disease. Arch Ophthalmol. 1968;80(2):171-176. doi:10.1001/archopht.1968.00980050173004