Final answer:
The most critical symptom to report to the healthcare provider is the patient's complaint of 'a curtain' over part of the visual field, suggesting a possible retina detachment or similar acute visual field loss that could lead to permanent vision damage.
Step-by-step explanation:
The finding that is a priority for the nurse to communicate to the health care provider in an emergency department patient who reports being struck in the right eye with a fist is d. The patient complains of "a curtain" over part of the visual field. This complaint could indicate a serious ocular injury, such as a retina detachment or other forms of acute visual field loss, and requires immediate attention to prevent permanent vision impairment or blindness. While other symptoms like headache, broken blood vessels in the sclera, and bruising are also important, the complaint of a "curtain" over the visual field suggests a more immediate threat to sight.
Related conditions that could cause visual field deficits, although not directly applicable to an acute injury, include effects from a growth on the pituitary gland creating bilateral hemianopia, and swelling related to meningitis putting pressure on the optic nerve. Moreover, a blow to the head can cause a hematoma which, if not treated quickly, can be fatal due to the pressure it exerts on the brain.