Visual symptoms are an important component in the morbidity encountered in patients with pituitary adenoma, can present at all stages of the disease, and may have a negative effect on daily activities and overall quality of life, according to a review published in the European Journal of Endocrinology.
Pituitary adenomas can compress adjacent visual structures, including visual pathways and ocular motor nerves, causing visual impairment. Visual morbidity in these cases may also be the result of the therapeutic approach, as it can develop as a complication of surgery or radiotherapy.
There is a wide variation in the prevalence of visual dysfunction at presentation of pituitary adenoma. The most common pattern of visual loss in these cases is bitemporal field defects, secondary to chiasmal compression; however, pituitary adenomas can cause many other visual complications, including oculomotor cranial nerve palsies.
Full ophthalmic evaluation is required as part of the assessment and management of all patients with pituitary adenomas compressing or abutting the visual pathway. This includes assessment of distance visual acuity, visual fields, color vision, the pupils, and fundoscopy. Optical coherence tomography is used to assess the optic nerve structure.
Visual recovery after transsphenoidal surgery occurs in various phases. Initial improvement may be rapid (within minutes to a few days); however, additional significant changes may continue over a longer time frame (months). Identifying factors that may predict favorable visual outcomes can aid in the assessment of the benefits of surgery. There is evidence that preoperative retinal nerve fiber layer thickness can predict postoperative vision recovery.
Visual deterioration after transsphenoidal surgery occurs in 2.3% of patients and is particularly common in patients undergoing transsphenoidal surgery after a previous transcranial approach. Late visual deterioration may result from traction on the optic chiasm which is pulled into the empty sella.
Pituitary tumor apoplexy resulting from an acute hemorrhage and/or infarction in a pituitary tumor may be associated with visual fields or visual acuity impairment, and although in many cases necessitates urgent decompressive surgery, there is some controversy regarding the optimal treatment strategy.
In cases of residual or recurrent pituitary adenoma after surgical intervention, radiotherapy may be considered. This treatment approach may result in radiation exposure and damage to the optic nerves, optic chiasm, and cranial nerves within the cavernous sinuses. On the other hand, there are reports of improvement in visual function after radiotherapy, but as surgery was completed beforehand in all these cases this may simply reflect late postsurgical improvement.
In patients with visual dysfunction secondary to prolactin-producing pituitary tumor, treatment with dopamine agonists can lead to visual improvement as early as 24 to 72 hours after treatment initiation.
In conclusion, “objective assessment of the visual function and the structural integrity of the anterior visual pathway is an essential component of modern management of pituitary pathology.”
Lithgow K, Batra R, Matthews T, Karavitaki N. Management of endocrine disease: visual morbidity in patients with pituitary adenoma. Eur J Endocrinol. 2019;181(5):R185-R197.