Computed Tomography Dimensions of the Lacrimal Gland in Normal Caucasian Orbits

Introduction: CT is frequently used to assess the lacrimal gland, yet no published reports exist of normal dimensions using this modality. We retrospectively evaluated CT data from normal orbits and measured the lacrimal gland dimensions. Methods: Two-hundred ninety-three consecutive orbital CT scans (586 orbits) of 282 patients were identified. Caucasian patients aged 18 years and older without known orbital disease were included. Traumatized orbits were excluded. All repeated scans were excluded. Length and width of the lacrimal gland were measured in axial and coronal sections with GE Centricity Software. The primary outcome was a descriptive analysis of the distribution of dimensions in normal orbits. A random subset of patient scans was measured independently by observers at different levels of training, and intraclass correlation coefficients (ICCs) were established. Results: Three hundred orbits (150 right orbits and 150 left orbits) of 282 patients were included. Normal distributions occurred with axial and coronal length measurements. Mean (10th and 90th percentiles) lacrimal gland axial length in right orbits was 14.7 mm (10.9 mm and 18.3 mm) and 14.5 mm in left orbits (10.3 mm and 18.3 mm). Coronal length averaged 17.7 mm in right eyes (13.9 mm and 21.8 mm) and 16.9 mm in left eyes (12.8 mm and 20.8 mm). Axial and coronal width showed non-normal distributions. No statistically significant difference in dimensions was found between genders, and a significant inverse linear relation occurred between gland size and age. Agreement was significant among the observers (ICC >0.7). Conclusion: This study presents a normal range of Caucasian lacrimal gland dimensions seen on CT. Lacrimal gland size decreases with age, and no gender difference exists. This range can aid in differentiating diseased and nondiseased lacrimal glands, especially when correlated with physical examination. This may be useful in clinical trials that involve lacrimal gland size.