Abstract
Purpose:
Ocular surface disease primarily includes aqueous tear deficiency (ATD), evaporative dry eye (EDE), and allergic conjunctivitis (AC). Until recently, the overlap between sub-types, especially with allergic conjunctivitis, has not been thoroughly examined in the literature. We looked at the prevalence of ocular surface disease categories in consecutive patients at two clinics.
Methods:
Objective tests were performed to classify the ocular surface disease into three categories: ATD, EDE, and AC. ATD was defined as Schirmer I score (without anesthesia) of 5 mm or lower. EDE was defined by digital meibomian gland expression of grade 1 or higher according to the grades described below. AC was defined as a papillary reaction of grade 1 or higher according to the Efron scale. The average measurement of both eyes were used. Combinations of Mixed were then counted with the remaining considered normal. The meibomian gland expression grades were 0: clear, low viscosity, easily expressible; 1: clear to mildly opaque, few particles, low viscosity; 2: opaque or many particles, medium viscosity; 3: opaque, solid (toothpaste); 4: not expressible.
Results:
258 patients were studied. The average age was 43.4±16.8 with 159 females and 98 males. 223 (86.4%) patients were classified as ATD, EDE, AC or Mixed with only 35 normals. EDE only was 10.8% (24/223), ATD only was 3.6% (8/223) and AC only was 41.7% (93/223). Out of all the mixed categories, the most significant overlap was the EDE and AC groups. There were 70 that had both conditions or 31.3% of the disease group. If a patient had EDE, there was an odds ratio of 1.10 that they also had AC.
Conclusions:
Very few normals truly exist in the population. In this sample, 86.4% had at least one of the three conditions. The Mixed category of EDE and AC is the largest. Perhaps low grade inflammation, especially in non-obvious meibomian gland dysfunction, may manifest as a papillary reaction first before downstream signs and symptoms appear. Allergic conjunctivitis appears to be a more prevalent condition than once thought and presents with EDE more than ATD. This category of overlap is found much more than EDE and ATD together.
Keywords: 486 cornea: tears/tear film/dry eye •
463 clinical (human) or epidemiologic studies: prevalence/incidence