# Central and Peripheral Vision

## Overview

This module describes how to test a patient’s peripheral and central vision using the confrontation test and Amsler grid test respectively.

## Indications

1. Patients complaining of loss of vision
2. Conditions with risk of loss of vision such as glaucoma
3. Suspected macular disease (Amsler grid particularly indicated)

## Contraindications

1. None

## Patient information & consent

Always verify your patient’s identity and obtain informed consent before proceeding.

### How do I explain this procedure?

“I need to test your central vision, and what you can see on the outer edges of your vision.”

### What can my patient expect?

“I will give you a chart with a grid to look at using each eye in turn, with the other eye closed. You must focus on the centerpoint and tell me if any part of the gridlines look distorted or disappear in any place.

For the testing of your outer/peripheral visual fields we will sit opposite each other and test each eye in turn. I will ask you to look at my nose and count fingers held on the edges of your vision. Don’t look away from my nose.”

### What is my patient’s role?

“If you use reading glasses, you should put them on for this test. It is important in the grid test that you focus on the center dot, and in the peripheral vision test that you keep eye contact. Don’t look directly at the gridlines or at my fingers during the test.”

## Preparation

###

### Documentation

1. Patient notes

### Equipment

1. Alcohol-based hand rub

2. Amsler grid notepad
   Amsler grid notepad

   Not always widely available

## Site & Positioning

Peripheral vision test: Patient should sit opposite you about 1 m away with your eyes at the same level.

Amsler grid: Patient should wear their reading spectacles, and hold the grid perpendicular to the line of sight, approximately 30-35 cm from the eye.

Perform the tests in normal ambient light.

## Procedure

Follow medical asepsis without gloves.

1. Perform hand hygiene.

2. If Amsler grid available: Ask the patient to cover one eye and to hold the Amsler grid at a normal reading distance. They should fixate on the central dot, and should report any

   distortion or absence
   distortion or absence

   Distortion indicates metamorphopsia, and absent lines indicate scotoma.

   of gridlines. Ask the patient to draw the area of visual distortion or loss on the Amsler grid notepad.

3. Repeat the test using the other eye.

4. With both eyes open, face the patient and ask them to focus on your nose. Ask if any part of your face appears

   missing.
   missing.

   This could indicate central scotoma or a hemianopia.

   Confirm with the Amsler grid as well.

5. Perform confrontation testing: Sit opposite the patient. Close your right eye with your hand, and the patient their left (vice versa). Ask the patient to make eye contact and not look away.

6. Test vision in each quadrant of the visual field by holding up fingers in each quadrant where you can see them, at about 50 cm from the patient. Ask the patient to

   count them.
   count them.

   Inability to count fingers in a quadrant suggests a visual field defect.

7. Hold up one finger in the left and one finger in the right visual field simultaneously and ask the patient which finger is

   clearer.
   clearer.

   This detects less dense visual field defects.

8. Hold up a finger, equidistant between you, and move it slowly inward from outside each visual quadrant. Ask the patient when they are

   able to see
   able to see

   The patient should be able to see the finger at the same time that it appears in your field of vision. If not, this suggests a visual field defect.

   the finger.

9. Repeat these tests with the other eye.

10. Record
    Record

    the results in patient notes.

## Troubleshooting

My patient has an abnormal test result.

Refer the patient to an ophthalmologist.

## Risks

1. None

## References

1. Pons J. How To Examine The Eye. In: Mash B, Blitz-Lindeque J, eds. South African Family Practice Manual. 2nd ed. Pretoria: Van Schaik Publishers; 2010: 134-137.