Incidentally there was an excellent post by Scout on DryEyeTalk today about the difference between typical airborne allergans and contact allergans.
Allergic conjunctivitis and dry eye syndrome.
Allergic conjunctivitis (AC) and dry eye syndrome (DES) are 2 of the most common anterior inflammatory disorders of the ocular surface and one does not preclude the coexistence of the other.
To examine the potential overlap between AC and DES as comorbidities.
Using the validated questionnaire known as Subjective Evaluation of Symptom of Dryness, we studied self-reported itchiness, dryness, and redness. In an outpatient optometric setting, 689 patients treated from January 1, 2007, to January 1, 2011, were surveyed for their ocular history and categorized according to their reported level of discomfort of itchiness, dryness, and redness.
Patients ranged in age from 5 to 90 years (median age, 25 years; 39.5% male; 60.5% female). In the studied 689 patients, clinically significant itchiness was found in 194 (28.2%), dry eyes in 247 (35.8%), and redness in 194 (28.2%). Symptom overlap was demonstrated in many of the patients. Of the 194 patients with itchiness, 112 (57.7%) had clinically significant dryness. In the 247 patients with dry eyes, 112 (45.3%) had clinically significant itch. Redness was apparent in 120 of the 194 patients with itch (61.9%) and 122 of the 247 patients with dryness (49.4%). Statistical analysis demonstrated that self-reported itchiness, dryness, and redness were not independent of each other (P<.001; Pearson χ(2) test). The odds of patients with "itchy eyes" also experiencing dry eyes were 2.11 times and the odds of these patients also experiencing redness were 7.34 times that of patients with nonitchy eyes.
Most patients with "itchy eyes" consistent with AC also have dry eyes and redness. These results suggest that some symptomatic patients concomitantly have features of AC and DES.
Ann Allergy Asthma Immunol. 2012 Mar;108(3):163-6.
Hom MM, Nguyen AL, Bielory L.