Sensory Service

Hemianopia What is hemianopia? Hemianopia is a vision impairment in which there is loss of part of the field of vision. It is a type of cerebral vision impairment, which means that the impairment is caused by processing problems in the brain rather than any structural problem with the eyes.

Visual field losses include loss of the right or left half-field (called hemianopia) and loss of the lower (inferior) field. Quadrantanopia is characterised by loss of vision in one-quarter of the visual field. Field loss can be absolute (no objects seen) or relative (small, dim object not seen). There are other types of hemianopia in which sight is lost in different parts of the field of vision.

In hemianopia, vision is lost on the same side in both eyes; for example right-sided homonymous hemianopia means that vision is lost on the right side in both eyes. Please note, this is not the same as having blindness in one eye. Visual acuity in the remaining visual field may be normal.

Children with a hemianopia will often adopt a head posture to shift their remaining field of vision more to the middle, which can be helpful for them.

Children may not be aware of people or objects to the affected side and may be inclined to bump into objects on their affected side when in an unfamiliar environment

Hemianopia can affect a child’s ability to read and how they move around objects. It can impact on learning, independence, and leisure activities.

We recommend teaching the child with a field loss to systematically scan visual materials during any visual and visual motor tasks. Scanning a page of images should be taught from the left to right and top to bottom. This is intended to “set” a motor habit for reading in English.

Children with right-sided hemianopia have difficulty reading left-to-right efficiently as they cannot see the next few letters or words as they move

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their eyes along the page. Reading will be more difficult for a person with a right field hemianopia than for a person with a left field hemianopia. This is because we make small, saccadic eye movements to the right as we read across a line of text, which helps us decode sentences. In a complete right field loss, there is no image of a word or letter to the right of fixation and thus no immediate cues to the decoding process.

Children with left-sided hemianopia can have difficulty finding the next line of text or beginning of words. This can be difficult especially for the beginning reader. Using the finger to follow back along the line that was read, and down to the next line may be helpful.

Lower (inferior) field loss affects scanning downward more than scanning to the right and left, so that the shift to the next line down in reading probably poses the most difficulty. Recommendations for left field loss above may be helpful for the child with inferior field loss.

Strategies to helpEnsure correct positioning in classroom allowing the student to access board or teacher without having to turn their head

Ensure that the student is aware of the entire piece of paper on which she/he is writing or drawing.

When reading, mark materials so that the reader will know where to start or stop e.g. putting a green dot at the start of a line and a red dot at the end of a line

A line along the right margin of a page will help with right vision loss

Turning the paper by 90 degrees so that the eyes can read down rather than along

Covering the beginning of words or lines as you read

Putting a finger at the end of each line of reading

Columns of text may be easier to read than whole pages of un-columned text.

Reading words that scroll across a screen. This website has a tool to help with this

Placement of the keyboard for computer use should be designed so that neither the keyboard nor the computer screen is far in the non-seeing field. Placement should be consistent so that the student can anticipate where to look and place the fingers for keying.

For lower field loss: Present visual materials on a slanted surface for viewing. A

computer screen is ideal as the surface is vertical. 2

The position of the child’s face relative to the slanted surface or screen is important. The surface should be biased toward the child’s seeing field, upward in the case of an inferior field loss, leftward in the case of right field loss, and rightward in the case of a left field loss.

Wide arrays and lines of text should be easier to read than columns of text for the child with lower field loss.

Individuals with field loss often develop head turns or tilts to aid in scanning into the non-seeing field. Consistent head turns/tilts can indicate that they have found their own way to adapt to the field loss. The child may tilt a page they are reading or writing on to see the whole surface better.

Once a child realises that he/she can only see to one side, they may be encouraged to physically turn to view objects .Until this skill is established, consider placing objects or activities on their visual side e.g. food .

Positioning in the classroom Seating in the classroom should be where the child’s seeing field is maximised for visual materials presented to the class as a whole, and to view the teacher during instruction. So, when facing the front of the classroom and the teacher, the child with a right field loss should be seated to the RIGHT facing the front, with the teacher on the child’s LEFT. And the child with a left field loss should be seated to the LEFT facing front with the teacher on the child’s RIGHT.

In a semi-circular group, placement of the child with a visual field loss should be guided by the activities and where the child’s attention should be directed. If the goal is to attend to the teacher, then the teacher should be well in the child’s seeing field. If the goal is to interact with the other children, then the child with a field defect should be positioned so that as many of the other children as possible are in the seeing field.

MobilitySafety during mobility is a very important consideration for children with visual field losses. Children with field loss may have difficulty localizing objects and people at distance, even if their distance visual acuity is normal. Field loss can cause difficulties crossing roads, cause individuals to collide with door frames, or objects that protrude from the side of vision loss, and can make it very difficult to navigate in crowded areas etc.

As in reading and other near tasks, a systematic approach to scanning objects at various distances must be designed and implemented across activities and environments.

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The child’s classroom, hallways, stairways, and playground should be evaluated for potential hazards.

These images simulate right sided hemianopia. The third image shows what someone with right sided hemianopia will see compared to someone with a full visual field as simulated in image one.

These various images simulate right and left sided hemianopia.

This image simulates inferior (lower) field loss

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This image simulates quadrantanopia (loss can be in any quadrant)

These 2 images simulate altitudinal hemianopia which affects the upper (superior) or lower (inferior) half of the visual field on both sides. 

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