To the Editor.
—Keratoconjunctivitis sicca (KCS) is a significantly disabling eye disease that affects millions of individuals throughout the world. Recently, three published reports have promoted the benefits of new tear substitutes—Healon,1 autologous serum,2 and a gel tear3—in the treatment of KCS. Each report tried to establish the safety and efficacy of their new tear substitute based on improvements in subjective complaints and objective clinical variables. However, the study design involved in each of these reports highlights the problems in designing studies that serve to evaluate the safety and efficacy of tear substitutes in individuals with KCS.First, care must be taken to include patients who have documented KCS without other complicating factors, such as blepharitis, keratitis medicamentosum, or intrinsic ocular surface disease (cicatricial ocular pemphigoid, atopic eye disease, etc). Without rigid inclusion and exclusion criteria, the improvement seen (subjective and objective) may not be related
Nelson JD. Treatments of Keratoconjunctivitis Sicca. Arch Ophthalmol. 1985;103(11):1630-1631. doi:10.1001/archopht.1985.01050110024005