title: Objective measurement of allergic reactions in the eye.
abstract: OBJECTIVE
  Conjunctival allergen challenge has become a useful model of human ocular allergy and an accepted method for studying the effects of topical antiinflammatory medications. Conjunctival allergen challenge reactions are typically evaluated in a subjective fashion. Erythema and edema are graded by observation, using a 0 to 4 scale. Itching is graded on a 0 to 4 scale by questioning the subject. We have reviewed the recent literature on conjunctival allergen challenge, including recently developed methods aimed at objective assessment of ocular allergic reactions, such as the erythema, edema, sensation, or EES, method.
  
  
  RESULTS
  Conjunctival erythema can be measured objectively using a spectroradiometer, or colorimeter, a device which measures the chromaticity of reflected light, and provides the x, or u', and y, or v', coordinates of any color. Edema of the eyelids and conjunctiva can be measured using a fractional millimeter reticule in the eyepiece of a slit lamp microscope. Ocular surface sensation can be evaluated using the aesthesiometer of Cochet and Bonnet, or by using a 'sensation index', a measurement that takes into account the intensity and duration of itching.
  
  
  CONCLUSIONS
  CAC reactions can be measured objectively using the erythema, edema, sensation method, as well as subjectively by observation and questioning.
authors.affiliation: Division of Ophthalmology, Scripps Clinic, La Jolla, California 92037, USA. MFried@ScrippsClinic.com
authors.forename: Mitchell H
authors.initials: MH
authors.lastname: Friedlaender
mesh_terms: D000485:Allergens / Q000009:adverse effects* / Q000276:immunology; D003233:Conjunctivitis, Allergic / Q000175:diagnosis* / Q000276:immunology*; D004487:Edema / Q000209:etiology / Q000276:immunology; D004890:Erythema / Q000209:etiology / Q000276:immunology; D006801:Humans; D011058:Pollen / Q000009:adverse effects* / Q000276:immunology; D014110:Touch / Q000276:immunology
chemical_list: D000485:Allergens