Related Experiment Video
Updated: Aug 31, 2026

Quantification of Optic Nerve Cross Sectional Area on MRI: A Novel Protocol using Fiji Software
Published on: September 4, 2021
Functional anatomy of the anophthalmic socket: insights from magnetic resonance imaging
Efstathios T Detorakis1, Robert E Engstrom, Bradley R Straatsma
1Departments of Ophthalmology, University of California, Los Angeles, California, USA. detorakis@jsei.ucla.edu
Purpose:
Changes in anophthalmic socket anatomy can significantly compromise esthetics and motility after enucleation. This study evaluated such changes by using magnetic resonance imaging (MRI) of enucleated and fellow orbits.
Methods:
High-resolution, surface coil MRI was performed in five patients after enucleation for uveal melanoma. Images were analyzed quantitatively to determine extraocular muscle (EOM) volume, maximum diameter, and length; orbital, optic nerve (ON), and orbital fat tissue (OFT) volume; and implant position. The fellow orbit was used as the control. Patients evaluated their satisfaction with the surgical results and were clinically examined.
Results:
Rectus EOM volume was slightly but not significantly reduced on the surgical compared with the control side. Oblique EOM and OFT volumes were unchanged. Rectus EOM length was significantly reduced in the surgical side, but maximum EOM diameter in central gaze position was slightly but not significantly greater on the enucleated side. Rectus EOM paths were not qualitatively changed by enucleation and continued to exhibit the influence of the connective tissue pulleys, which retained motility, as appropriate to EOM contraction. Implants were located significantly posterior to the normal globe location.
Conclusions:
Enucleation does not significantly change EOM volume, but shortens EOM paths, a change that would be expected to alter their mechanical properties. EOM pulleys appear to retain their functional role in enucleated orbits.
Related Concept Videos
Cranial Bones: Lateral View
The temporal bone forms the lower lateral side of the skull. The temporal bone is subdivided into several regions. The flattened upper portion is the squamous portion of the temporal bone. Below this area and projecting anteriorly is the zygomatic process of the temporal bone, which forms the posterior portion of the zygomatic arch. Posteriorly is the mastoid portion of the temporal bone. Projecting...
Cranial Bones: Superior and Posterior View
The frontal bone is the single bone that forms the forehead. At its anterior midline, between the eyebrows, there is a slight depression called the glabella. The frontal bone also forms the supraorbital margin of the orbit. Near the middle of this margin is the supraorbital foramen, the opening that provides passage for a sensory nerve to the forehead. The frontal bone is thickened just above each supraorbital margin,...
Accessory Structures of the Eye
Magnetic Resonance Imaging
Anatomy of the Eyeball
