A case with transient refractive change after removal of pituitary tumor

Background Refractive change can be caused by systemic illnesses such as Lupus erythematosus, thyroid deficiency, and diabetes mellitus. However, refractive change after pituitary tumor removal has so far not been reported. Case presentation A 62-year-old woman presented with blurred near vision 10 days after trans-sphenoidal surgery (TSS) for a pituitary tumor. Around the same time, she experienced intercurrent hyponatremia. The corrected visual acuity of both eyes was 20/20, the spherical equivalent of the right eye was −2.125 diopters, and of the left eye was −2.0 diopters before TSS. However, 11 days after TSS, the spherical equivalent of the right eye changed to −0.75 diopters, and that of left eye changed to −1.125 diopters without hyperglycemia. There were no changes in the corrected visual acuity during the follow-up. Conclusion We demonstrated a case with transient refractive change after TSS. The following mechanism is proposed: Hyponatremia induced by the pituitary tumor removal causes an osmotic change in the aqueous humor with lens swelling. This case report is a reminder to both ophthalmologists and neurosurgeons that ophthalmological factors such as lens thickness and axial length should be taken into account when conducting preoperative examinations especially for patients undergoing TSS.