This is blindness of the nasal half of the visual field of one eye and the temporal half of the other.

Homonymous hemianopsia is caused by an optic chiasm lesion. These lesions could be neoplasms (either intrinsic or extrinsic), or aneurysms.

There may be a lack of awareness of the problem, except for bumping into things on the side of the defect, or having trouble reading and seeing the next word or line. The type of visual field abnormality will reveal where the lesion is located. Visual problems may include: diplopia, and ptosis.

Lesions may be identified by computed tomography (CT) scan or magnetic resonance imaging (MRI). Other tests may include: visual field; visual acuity; ophthalmoscopy; and slit lamp.

Treatment of the underlying disease condition causing the visual field loss may be helpful. An eye patch may be used for diplopia.

Impairment of visual fields may lead to injury by falling, stepping in front of on-coming vehicles, and unawareness of hazards on the affected side.

• May be entitled to special monthly compensation where the Veteran has a single service-connected disability rated as 100% with additional service-connected disability or disabilities independently ratable at 60% or more, which are separate and distinct from the 100% service-connected disability and involves different anatomical segments or bodily systems. See  38 CFR 3.350(i)(1) – Special Monthly Compensation (SMC).

• Consider entitlement to specially adapted housing under 38 U.S.C. 2101(a)(2)(A)(i) if there is visual impairment to the degree specified in 38 CFR 3.809(b)(2).

• The veteran, spouse, surviving spouse or parent will be considered in need of regular aid and attendance if he or she is blind or so nearly blind as to have corrected visual acuity of 5/200 or less, in both eyes, or concentric contraction of the visual field to 5 degrees or less (38 CFR 3.351(c)(1)).

• Consider entitlement to automobile allowance and/or automobile adaptive equipment if there is visual impairment to the degree specified in 38 CFR 3.808(b)(3).

• To determine the evaluation for visual impairment when both decreased visual acuity and visual field defect are present in one or both eyes and are service connected, separately evaluate the visual acuity and visual field defect (expressed as a level of visual acuity), and combine them under the provisions of 38 CFR 4.25. (38 CFR 4.77)