Prognostic value of optical coherence tomography in chronic chiasmal compression

Introduction Sellar and parasellar region lesions, such as pituitary adenoma, often lead to the compression of the optic chiasm. Consequentialy, visual field (VF) defects and loss of visual acuity are common complaints in these patients. The aim of this report is to evaluate if optical coherence tomography, measuring retinal nerve fibre layer (RNFL) and ganglion cell complex thickness (GCC), offers a reliable prediction of visual outcome in patients with chronic chiasmal compression from a pituitary macroadenoma. Case outline We present a case of chronic chiasmal compression from a pituitary macroadenoma with an initial binocular VF defect and low values of optical coherence tomography parameters binocularly. The average value of RNFL on the right eye pre/postoperatively was 48/79 mu m, while on the left eye it was 56/63 mu m. The average value of GCC pre/postoperatively was 47/46 microns on the right and 45/46 microns on the left eye. Six weeks after surgical optochiasmal decompression, macular GCC on both eyes and RNFL on the left eye remained largely unchanged, while RNFL of the right eye exhibited increases in thickness, as the postoperative consequence of the removal of the conduction block. Neither VF nor visual acuity showed postoperative improvement. Conclusion Irreversible damage to the GCC and RNFL by longstanding compression results in poor visual outcome after surgery. Ganglion cell layer of the macula is a more accurate and reliable indicator of postoperative visual outcome.