Unbiased Estimation of the Eyeball Volume Using the Cavalieri Principle on Computed Tomography Images

Abstract

The size of the eyeball has been the subject of a few studies. None of them used stereological methods to estimate the volume. In the current study, we estimated the volume of eyeball in normal men and women using the stereological methods. Eyeball volume (EV) was estimated using the Cavalieri principle as a combination of point-counting and planimetry techniques. We used computed tomography scans taken from 36 participants (15 men and 21 women) to estimate the EV. The mean (SD) EV values obtained by planimetry method were 7.49 (0.79) and 7.06 (0.85) cm in men and women, respectively. By using point-counting method, the mean (SD) values were 7.48 (0.85) and 7.21 (0.84) cm in men and women, respectively. There was no statistically significant difference between the findings from the 2 methods (P > 0.05). A weak correlation was found between the axial length of eyeball and the EV estimated by point counting and planimetry (P < 0.05, r = 0.494 and r = 0.523, respectively). The findings of the current study using the stereological methods could provide data for the evaluation of normal and pathologic volumes of the eyeball.

Measurement of normal ocular volume by the use of computed tomography

“…[3] Consequently, if the volume of one eye is known then the volume of the other eye (if normal) can be extrapolated as it will fall within the calculated value of ±1% of the known eye volume. We reported a total average volume of both eyes of 5282 mm 3 which is smaller than that reported by Galluzzi et al [1] and Acer et al, [9] but less than that reported by de-Graaf et al [10] (mean ocular volume of the normal eyes was put at 6,018 mm 3 , 7,060 mm 3 and 5018 mm 3 respectively). Similarly, in a study in Nesbraska, USA, on CT measured ocular volume on 228 eyeballs, the value obtained was 7,181 mm 3 .…”

“…The difference in ocular volume between the sexes was less than 100 mm 3 which may be considered of minimal significance as it was less than 2%. But this was not the case in the study by Acer et al [9] in which the percentage difference in the mean between ocular volumes of both sexes was about 3.6%. We observed that the patients in our study showed consistent increase in ocular volume in either globe of male patients than of females in those above 60 years.…”

Three-Dimensional Eyeball and Orbit Volume Modification After LeFort III Midface Distraction

“…Because of the lack of a bony anterior border, a manual aid was necessary during the volume determination of the data sets. Nout et al 7 who only used sagittal CT slices, defined the 12,13 The summation of the areas obtained from manual segmentation of a large number of axial or coronal slices could be performed in different ways, including the following: (1) a manual calculation by point-counting and multiplying the surface factors of each element for each slice, (2) a manual outline of each slice and computed calculation, (3) a summation of the cross-sectional areas of each section. [12][13][14][15] Orbital volume measurement with these methods is very time consuming and, therefore, is not clinically useful.…”

Ocular biometry by computed tomography in different dog breeds

“…Computed tomography is widely used for ocular biometry in people, both for research and to establish reference ranges for certain cohorts . Standard measurement methods have been established . In veterinary ophthalmology, it would be useful to have breed‐specific reference values for research purposes and for skull CT interpretation.…”