Abstract
Purpose:
To establish levels of keratitis and other signs of dry eye disease in self-reported normal, asymptomatic subjects over 40 years of age.
Methods:
The subject population consisted of forty normal subjects over 40 years of age with no prior diagnosis of dry eye or other ocular surface disease and no history of artificial tear use. Subjects with current symptoms of ocular discomfort or dry eye were excluded at screening. Subjects were required to avoid contact lens wear for 72 hours prior to the visit. All subjects underwent a slit lamp examination including tear film break up time (TFBUT), fluorescein and lissamine, staining, and Schirmer’s test. Subjects were considered normal if they had a maximum fluorescein staining score of 1 on a scale of 0 to 4 (0 being none and 4 being severe) in only one region of the cornea, and less than a score of 1 in the remaining regions of the cornea in both eyes, and Schirmer’s test scores ≥12 mm in both eyes. Lissamine staining scores and TFBUT were documented but were not used for definitive diagnosis.
Results:
No subjects had symptoms at the time of examination. Of 40 subjects, 5 demonstrated staining consistent with contact lens wear and were excluded. Of the remaining 35 subjects: 3 reported a history of dry eye symptoms though they were currently asymptomatic, and were excluded from further analysis; 10 had clinically significant fluorescein staining in at least one region of the cornea (≥1.5 score) and Schirmer’s scores of <12 mm in at least one eye; 6 had clinically significant fluorescein staining in at least one region of the cornea (≥1.5 score) and normal Schirmer’s scores; 12 had Schirmer’s scores<12 mm in at least one eye but normal fluorescein staining. Only 4 subjects of 35 fully qualified with no clinically significant fluorescein staining and normal Schirmer’s scores.
Conclusions:
Identifying age-matched control subjects in dry eye studies is challenging. These data demonstrate the prevalence of dry eye signs in a normal population over 40 years of age. Of 35 subjects, 28.6% had both abnormal fluorescein staining and Schirmer’s scores, (17.1% had keratitis, and 34.3% had abnormal Schirmer’s scores). The presence of signs of dry eye in a normal subject population contribute to the difficulty of demonstrating resolution of endpoints, and provide another obstacle to dry eye clinical trials. Only 11.4% of a supposed population of normals actually had no clinically relevant signs of dry eye.
Keywords: 486 cornea: tears/tear film/dry eye •
468 clinical research methodology