Conjunctival vasculature in the assessment of anemia

To assess the correlation of the bulbar conjunctival blood column (BCBC) with anemia.

A prospective, randomized, masked, two observer case series.

Inpatients on hospital wards; outpatients in both the Hematology-Oncology and Ophthalmology Clinics.

Observations of the palpebral conjunctival hue (PCH) and BCBC by two observers masked to the patient's diagnosis, laboratory test results, and other's observations. The PCH and BCBC were correlated by slit-lamp examination with serum hemoglobin values. Different threshold levels for anemia were defined as hemoglobin <10, <11, and <12 mg/dl.

The parameters included determination of (1) the conjunctival hue, assessed as pink or pale and (2) the bulbar conjunctival blood column, assessed as full (normal), granular, or discontinuous. These data were compared against the patient's hemoglobin level.

Mean hemoglobin was 11.0+/-2.2 mg/dl. Sensitivity of the BCBC and PCH for anemia was 83%-94% and 38%, respectively, regardless of the definition of anemia. Specificity of BCBC improved with increasing hemoglobin threshold levels for anemia: 56% (hemoglobin <10 mg/dl) to 73% (hemoglobin <12 mg/dl); specificity for PCH ranged from 82% to 94%. The BCBC was significantly (P<0.03) associated with anemia for hemoglobin <11 mg/dl for both observers (logistic regression, Spearman correlation). There was a significant (P<0.05) association of PCH with anemia only for hemoglobin <10 mg/dl with logistic regression (one observer only) and with Spearman correlation (both observers).

The BCBC is significantly associated with anemia, with higher sensitivity and only slightly less specificity than PCH.