worth 4 dot test.pptx

worth' four dot test complete description

1. WORTH’S FOUR DOT TEST By: Maham qamar OD 8 th semester

2. Introduction: The Worth's Four Dot test also known as the Worth Four Light Test abbreviation W4LT, is one simple clinical test mainly used for assessing a patient's degree of binocular vision. Worth four-dot is a gross test and checks for suppression by asking the patient to report the number and color of dots they can see when looking through red-green goggles at four lights or dots of different colors.

3. Indications: Manifest strabismus Diplopia Suppression

4. Equipment and set up The W4LT instrument is composed of a silver box, which has 4 lights inside it. The 4 lights are arranged in a diamond formation, with a red light at the top, two green lights at either side (left and right) and a white light at the bottom. While the patient wears red and green glasses. Red glass filter in front of the patient´s right eye and the green filter in front of the left eye.

5. Procedure: Explain the test and procedure to the patient: “This test tests whether you are using both eyes at the same time to view. First you must place the red/green goggles over the patients' eyes. Red glass filter in front of right eye and green Infront of left. Next you must dim the room lighting. This allows the patient to see the lights better or improves fusion. This test can be performed for a distance (6m) and can be performed at approximately one third of a meter, or 33 centimeters, with a handheld Worth's Four Lights torch.

6. Questions: The questions are: How many lights are you seeing? What color are the lights you see? Describe the location of the lights? Are all the lights in line? Or are some higher than the others? Do all the lights show up at one time, or are they flashing on and off?

7. Interpretation

8. Binocular single vision: In the absence of a deviation, the patient will see the lights exactly as they appear, so it indicates that the patient have binocular single vision and normal retinal correspondence. When questioned t hey will report that; They see 4 lights, 1 red, 2 green and one mixed color. This is recorded as : W4LT (D): 4 lights (BSV) Abnormal retinal correspondence : It will be demonstrated on cover test that the patient has a manifest deviation. When questioned about the lights the patient will give a normal response and will see the lights exactly as they appear.

9. Suppression: Suppression of left eye: The patient sees two red dots Suppression of the right eye: The patients see three green dots. Right eye suppression Left eye suppression

10. Horizontal diplopia: Esotropia: In an esotropic (ET)deviation, the patient will experience uncrossed diplopia. When questioned about the position of the lights, they will report that: They see 5 lights, 2 red and 3 green The lights are horizontally displaced, seen side by side The 2 red lights from the right eye are seen on the right side The 3 green lights from the left eye are seen on the left side This is recorded as: W4LT (D): 5 lights (Uncrossed Diplopia) ET

11. Exotropia: In an exotropia (XT) deviation, the patient will experience crossed diplopia. When questioned about the position of the lights, they will report that: They see 5 lights, 2 Red and 3 Green The lights are horizontally displaced, and are seen side by side The 2 Red Lights from the Right eye are on the left side The 3 Green lights from the Left eye are on the right side This is recorded as: W4LT (D): 5 lights (Crossed Diplopia) XT

12. Vertical diplopia: Hypotropia or hypertropia In cases of vertical deviation patients will report that: They see 5 lights: 2 red and 3 green The lights are vertically displaced in relation to one another The green lights (left eye) are on top of the red lights (right eye), which is interpreted as : Right Hypertropia or Left Hypotropia The red lights (right eye) are on top of the green lights (left eye), which is interpreted as: Right Hypotropia or Left Hypertropia Vertical deviation with right hypotropia and left hypertropia Vertical deviation with left hypotropia and right hypertropia

13. Advantages: The Worth four-dot test is widely accessible, inexpensive, affordable, and easy to utilize. It is a great test to test fusion at a distance or near. Can be quick and simple to perform in the clinic as the test is easy to orientate and the red green goggles are simply put over the eyes. Relatively easy to record and interpret the results Good starting point when investigating the nature of diplopia i.e., to find manifest, intermittent, crossed or uncrossed diplopia There are no large glasses frames such as in the Bagolini striated glasses test, so the goggles are minimally obstructive to the patient's vision. Refractive correction can be worn under the goggles.

14. Disadvantages: Subjective in nature and relies on patient responses People with Red/green color blindness cannot accurately perform the test as the colors used on the test are red and green If performing the test twice, for example at near and at distance, the patient (especially children) may remember their previous answer and simply give the same answer from the last test, providing inaccurate results. The patient needs to have fusion and stereopsis in order to obtain exact results.

15. References: https://thevisionpedia.com/worth-four-dot-test/ https://www.seevividly.com/info/Binocular_Vision/Vision_Tests/Worth_4_Dot https://en.wikipedia.org/wiki/Worth_4_dot_test#Recording_and_interpreting_outcomes