AMSLER CHARTS.pptx

AbhishekKashyap655919 598 views 28 slides Dec 09, 2022
Slide 1
Slide 1 of 28
Slide 1
1
Slide 2
2
Slide 3
3
Slide 4
4
Slide 5
5
Slide 6
6
Slide 7
7
Slide 8
8
Slide 9
9
Slide 10
10
Slide 11
11
Slide 12
12
Slide 13
13
Slide 14
14
Slide 15
15
Slide 16
16
Slide 17
17
Slide 18
18
Slide 19
19
Slide 20
20
Slide 21
21
Slide 22
22
Slide 23
23
Slide 24
24
Slide 25
25
Slide 26
26
Slide 27
27
Slide 28
28

About This Presentation

A presentation on the history and well defined description on amsler chart, along with the various types of amsler chart and its uses, advantages, disadvantages and limitation. The procedure of performing the test and the sequences of question asked during the test is also well elaborated.


Slide Content

AMSLER CHARTS Presented By- Name- Abhishek Kashyap B.Optom 3 rd year Ridley college of optometry

Layouts History Introduction Types Procedures Advantages, disadvantages and limitation Interpretation

History In 1920s, Marc Amsler, a swiss ophthalmologist, designed the amsler grid

Introduction The Amsler Grid is a rapid, qualitative technique designed to test central 20 ̊of the visual field It comprises of seven charts All charts are in a shape of square, covering an area of 100cm² (10cm x 10cm)

Each square of the grid is 5mm, subtending approximately 1 ̊ at 30 cm It is a diagnostic tool that is used mainly in screening, detection and monitoring macular diseases as well as optic nerve and visual pathway lesions

Types Chart 1: The most familiar and widely used chart It comprises a high contrast white grid against the black background with a central fixation point It enables in identification of various forms of distortion as well as relative scotomas

Chart 2: Similar to chart 1 with two additional diagonal white lines crossing through the central fixation spot It is use for patients having a central scotoma

Chart 3: Similar to chart 1 but with red grid It is used in the evaluation of color scotoma and desaturation which occurs in toxic maculopathy, optic neuropathy, chiasmal lesion It is also aid in the identification of malingering patients when used in conjuction with red and green filter

Chart 4: It displays a series of random white dot against the black background Its soul purpose is in detection of scotoma

Chart 5: It consist of 20 evenly spaced white parallel lines against the black background The chart can be rotated to change the orientation of the lines And is used to investigate metamorphopsia along specific meridians

Chart 6: Similar to chart 5 but has black lines against the white background This chart has additional lines with half the spacing in central 2 ̊ area, subtending a small angle of 0.5 ̊ at the eye So, it enable more detail examination

Chart 7: Similar to chart 1 but contains additional square of 0.5 ̊ subtends in central 8 ̊ x 6 ̊ area So, it provide a more sensitive assessment of the macula

Modified Amsler Charts Yannuzzi Card Diamond Chart Transilluminated Grid Yannuzzi Card

Procedure First, the patient is asked to seat comfortably with the appropriate near correction As the working distance for the test is 30 cm, a +3.25 D near add should be used for absolute presbyopes or the patient’s own spectacles are usually satisfactory Use a single vision glasses or trial lenses, but avoid bifocal and multifocal lenses

The examiner should position such that he/she could be able to occlude the non-viewing eye and measure the working distance Keep the room light well- illuminated Now, the patient is asked to look at the central dot of the chart at all the time with right eye and occluding the left eye

Patient is instructed to show on the chart if he/she notices any missing and distorted area/ lines Repeat the same procedure for left eye occluding the right eye

Sequences of questions Can you see the central white dot? Keeping the gaze fixed on the white dot, can you see the four corners/sides of the squares? Are any of the small squares blurry or missing on any part of the grid? Do any of the horizontal or vertical lines that make up the squares appear wavy or bent?

5. Is any part of the grid shimmering, flickering, or colored?

Advantages Rapid test Cheap Portable Easy to use

Disadvantages Can assess only 20 ̊ of the visual field area Complete subjective test

Limitation Completion phenomenon Use of high contrast well illuminated grid against which relative scotoma can easily be missed Patient with well established central scotoma can adapt to this defect by fixating eccentrically when viewing the chart, thereby giving rise to apparent paracentral scotoma

4) Chart 3 provide poor contrast, which make the chart difficult to see, giving rise to a high level of false positive response

Interpretation

Reference Primary care Optometry, 4 th edition, by Theodore Grosvenor, page no.  155-156 Clinical procedures in optometry, page no. 436- 446