Exophthalmometric values and periocular anthropometry among 10 to 18 year old Nigerians

Abstract

The orbit is a bony cavity with an average volume of 45ml and houses the eyeball along with various other structures such as the extraocular muscles, retro-orbital fat, the lacrimal gland and the associated neural and vascular structure s | I |. Exopluhatonometry is the quantitative assessment of the position of the globe in the orbit | 2 | and many disease s of the orbit manifest with abnormal protrusion of the eye lore which exophthalmometry is a routine test to evaluate the patients. The Hartco cxophthalmomctc r is the most commonly used cxophlhalmomctcr in clinical practice because it is a handy and inexpensive device which produces consistently reproducible results, though, it cannot be used in individuals with defects in the lateral orbital wall [3]. Anthropology reveals that the skeletal build-up of humans is unique in different races, and that males and females have different bony framework [4]. T h e normal morphology and functional values of eyelid positions also vary widely between race, sex, and age |4|. Therefore, knowledge of the average dimensions of periocular structures, facial proportions and the relationships between individual segments of the face is protean. Opinions differ on the effect of age on cxophlhalmomctric value (EV) and palpebral dimensions (PD). However, many authors [5-7] reported that EV increases during the first two decades of life, and stabilizes thereafter, thus, suggesting that EV at the end of the second decade is a true representation of EV in adulthood. Heterogeneity in EV and PD values and their correlates among different populations had been clearly demonstrated [5, 8-12]. Therefore, when evaluating the results of these measurements, the normal values specific to the population must be taken into consideration. However, only a few studies f 13-15] have reported normative exophthalmometry data in the Nigerian population and these were conducted mainly among the older age groups, thus, values based on studies among Caucasians are used as reference in the country. This study thus aims to define normal EV and PD values in this select group of healthy Nigerian population.