BASIC EYE EXAMINATIONS and nursing management

Anatomy of the human eye conditions and related management

1. BASIC EYE EXAMINATIONS DR ARMAH , FWACS

2. EYE EXAMINATION DISTANT VISUAL ACUITY TEST PIN HOLE TEST . RED REFLEX TEST PUPILLARY REACTIONS--- RELATIVE AFFARENT PUPILLARY RESPONSE OCULAR MOTILITY TESTS

3. EYE EXAM TONOMETRY CORNEAL LIGHT REFLEX CONFRONTATION FIELD TESTING DIRECT OPHTHALMOSCOPY

4. EYE EXAM COLOUR VISION TESTING FLUORESCEIN STAINING OF CORNEA UPPER EYELID EVERSION

5. EQUIPMENT FOR BASIC EYE EXAM SNELLEN DISTANT VISUAL ACUITY CHART NEAR VISION CARD PEN TORCH LIGHT DIRECT OPHTHALMOSCOPE MYDRIATIC TOPICAL ANAESTHETIC FLUORESCEIN STRIPS OR DROPS SLIT-LAMP BIOMICROSCOPE

6. PIN HOLE TEST

7. COLOUR DESATURATION TEST

8. DISTANT VISUAL ACUITY TESTING Usually record as a ratio or fraction comparing patient performance with an agreed-upon standard , eg , 6/60 or 20/200 or 0.1 . The numerator represents the distance between the client and the eye chart. The denominator represents the distance ( metres ) at which a person with normal acuity can read the smallest letters/ optotypes OR object / optotype size

9. DISTANT VISUAL ACUITY Visual acuity of 20/20 or 6/6 or 1.0 represents normal visual acuity . British system uses 6m as test distance. American system uses 20ft as test distance. If limited by space a distance of 3m or 10ft can be used in addition to a plain mirror and a reverse Snellen chart.

10. DISTANT VISUAL ACUITY By convention, the right eye is tested and recorded first whilst the left eye is covered with an opaque occluder . The left eye is then tested and recorded whilst the right eye is occluded. If the visual acuity is 0.5 or less in one or both eyes, repeat the test with the subject viewing the test chart through a pinhole occluder and record the results.

11. DISTANT VISUAL ACUITY If a patient cannot see the largest Snellen letters, you proceed as follows: (1)Reduce the test distance between patient and the chart . Eg , 2/60. (2)If the patient is unable to see the largest Snellen letter at 1m(3ft) then hold up one hand, extend two or more fingers,and ask the patient to count the number of fingers.

12. DISTANT VISUAL ACUITY Record distance at which counting fingers is done accurately,eg,CF at 1m. If the patient cannot count fingers, then do hand movement test , eg , HM at 0.5 m. If patient cannot detect HM , then use a penlight to determine whether or not he or she has light perception ,LP , or no light perception , NLP. If patient has LP, then check for light projection.

13. DISTANT VISUAL ACUITY VISUAL ACUITY IMPAIRMENT VRS VISUAL DISABILITY. Any difference between the two above?

14. NEAR VISUAL ACUITY TESTING This is tested if the patient has a complaint about near vision , eg , presbyopia . This could also be done if distant acuity testing is difficult or impossible , eg , a bed-ridden patient in the admission ward. Rosenbaum pocket vision screener is used and the test distance is 14in (35cm).

15. NEAR VISUAL ACUITY TESTING However, there are other near charts with varying letter size designations and test distances. To avoid ambiguity, both the letter size designation and test distance should be recorded, eg , J5 at 14in, 6 point at 40cm.

16. VISUAL ACUITY ESTIMATION IN PREVERBAL CHILDREN VISUAL BEHAVIOUR fix and follow light, face and colourful objects. Smile back to a smiling mother, father or any relative. Withdrawal or a change in facial expression in response to light or sudden movement indicates the presence of vision.

17. VISUAL ACUITY ESTIMATION IN PREVERBAL CHILDREN Note that sound is not part of the stimulus whilst checking for vision in preverbal children. A brisk pupillary response to light suggests the presence of vision, except a brisk pupillary response in a child with cortical blindness.

18. VISUAL ACUITY ESTIMATION IN INFANTS TO 2-YEAR-OLDS It is possible to assess visual function in infants , not visual acuity. To test for amblyopia in infants (from a few months to about age 2),you need to cover each eye in turn with the hand or, preferably , an adhesive patch and note how the child reacts.

19. VISUAL ACUITY ESTIMATION FOR AGES 2 TO 4 Picture cards can be used to test visual acuity in children between 2 and 3 years of age. At age 3 ( or before, if the child can follow directions and communicate adequately, VA can be tested with the tumbling E test. Use of an adhesive patch is the best way to ensure full monocular occlusion and accurate VA measurement in children at these ages.

20. VA ESTIMATION FOR AGES 2 TO 4 YEARS Young children may not quite reach 6/6 acuity.This is no cause for concern as long as vision is at least 6/12 and both eyes are equal.

21. VISUAL ACUITY ESTIMATION FOR AGES 4 AND 5 YEARS AND UP The Snellen chart may be used to test VA in children age 4 or 5 years and up who know the letters of the alphabet.

22. THE RED REFLEX TEST Light reflected off the fundus of the patient produces a red reflex when viewed through the ophthalmoscope at arm’s length from client. A normal red reflex is evenly coloured , is not interrupted by shadows, and is evidence that the cornea, anterior chamber , lens , and vitreous are clear and not a significant source for decreased vision.

23. RED REFLEX TEST Opacities in the media-- such as corneal scar , cataract , and vitreous hemorrhage—appear as black shadows and can be best appreciated when pupils are dilated .

24. PUPILLARY REACTION Direct and consensual pupillary reactions to light are evaluated in a room with reduced illumination and with the patient looking at a distant object . The swinging flashlight test is used for detection of Relative Afferent Pupillary Defect in the anterior visual pathway.

25. OTHER PUPILLARY ABNORMALITIES Pupillary tears Posterior synechiae Anisocoria

26. CORNEAL LIGHT REFLEX TEST PTOSIS UPPER EYELID RETRACTION STRABISMUS-------Note pseudo- esotropia

27. ALTERNATING EXOTROPIA

28. PSEUDO-ESOTROPIA

29. MARGINAL REFLEX DISTANCE MRD

30. CORNEAL LIGHT REFLEX Note that the corneal light reflex is also used in the diagnosis of ptosis and eyelid retraction . MRD—Marginal Reflex Distance. Normal is about 4 to 4.5mm.

31. CONFRONTATION FIELD TESTING The examiner takes a position about 1 m in front of the patient . Patient covers the left eye with the palm of the left hand whilst the examiner closes the right eye . Thus the field of the examiner’s left eye is used as a reference in assessing the visual field of the patient’s right eye .

32. CONFRONTATION FIELD TESTING The patient fixates on the examiner’s left eye and then count the fingers of the examiner in each of the four quadrants of the visual field. The procedure is repeated for the left eye, with the patient covering the right eye with the palm of the right hand , and the examiner closing the left eye.

33. OCULAR MOTILITY TEST DUCTIONS VERSIONS CARDINAL FIELDS OF GAZE(6) PRIMARY, SECONDARY AND TERTIARY FIELDS OF GAZE.

34. OCULAR MOTILITY TEST OCULAR ALIGNMENT CORNEAL LIGHT REFLEX TEST HETEROPHORIAS—LATENT OCULAR DEVIATIONS ESOPHORIA EXOPHORIA HYPOPHORIA HYPERPHORIA

35. OCULAR MOTILITY TEST HETEROTROPIAS—MANIFEST OCULAR DEVIATIONS ESOTROPIA EXOTROPIA HYPERTROPIA HYPOTROPIA ORTHOPHORIA

36. OCULAR MOTILITY TESTS COVER-UNCOVER TEST ALTERNATE COVER TEST HIRSCHBERG TEST KRIMSKY TEST

37. OCULAR MOTILITY TEST PRISM COVER TEST FORCED DUCTION TEST

38. OCULAR MOTILITY TEST COVER TEST This depends on abolishing fusion so that the eyes assume their position of rest. Fusion of the two eyes is abolished by covering one eye.

39. OCULAR MOTILITY TEST METHOD The patient looks at a distant object. (a)While observing one eye, cover and uncover the other eye.The movements of the observed and the eye under cover are observed. (b)Repeat this process with the other eye and then alternately.

40. OCULAR MOTILITY TEST INTERPRETATION (1)If there is no movement , patient has orthophoria (2)If there is inward movement on removing the cover then patient has esophoria.Note that on removal of the cover the esophoric eye will move outwards to take up fixation of the distant object.

41. OCULAR MOTILITY TEST (3)If there is outward movement on removing the cover then the patient has exotropia . Note that upon removal of the cover the exotropic eye moves inward to take up fixation of the distant object. QUESTION What are the cover test findings in hyperphoria and hypophoria

42. OCULAR MOTILITY TEST (1)MADDOX ROD TEST (2)MADDOX WING TEST (3)PRISM VERGENCE TEST (1)The Maddox Rod is done to find out heterophoria for distance. Fusion is broken by the alteration in the apperance of the retinal image in one eye.

43. OCULAR MOTILITY TEST (2)MADDOX WING TEST The Maddox wing is an instrument that dissociates the two eyes for near fixation (1/3 of a metre ) and measures the amount of heterophoria . METHOD The patient is asked to hold the Maddox wing and look through the two observation slits with both eyes open.

44. OCULAR MOTILITY TEST The right eye sees a white pointing vertically and red arrow pointing horizontally to the left. The left eye sees the white figures in the horizontal lines and red figures in the vertical line. The figures are calibrated in degrees to read deviation. Patient is asked to read the figures corresponding to the red and white arrows

45. OCULAR MOTILITY TEST INTERPRETATION Any deviation an esophoria , exophoria or hyperphoria which can be read on the scale.

46. OCULAR MOTILITY TEST METHOD Patient is seated 6m from a spot of bright light in a dark room. A Maddox rod consisting of 5 cylinders of red glass fused side by side in a supporting disc is placed in front of one eye . The spot of light appears as a red line . If the cylinders are placed with their axis horizontal , then the red line will appear vertical.

47. OCULAR MOTILITY TEST INTERPRETATION If there is orthophoria the bright spot will appear in the centre of the vertical or horizontal red line depending on the orientation of the Maddox rod. TYPE OF HETEROPHORIA By the position of the vertical or horizontal red line in relation to the spot of light, exact type of heterophoria is detected.

48. OCULAR MOTILITY TEST ILLUSTRATE LATERAL AND VERTICAL DEVIATIONS USING RED LINE AND WHITE DOT ANGLE OF DEVIATION The strength of prism which is necessary to be placed in front of the Maddox or the other eye so that the red line and white spot appear together; indicates the angle of deviation.

49. OCULAR MOTILITY TEST NATURE OF DEVIATION It is indicated by the position of the prism whether base in , base out , base up , or base down.

50. OCULAR MOTILITY TEST (3)PRISM VERGENCE TEST The actual measurement of the deviation and strength of the muscles involved are tested. The muscles are forced to act with maximum effort against prisms. METHOD The patient is seated 6m from a light source and looks at the Maddox tangent scale.

51. OCULAR MOTILITY TEST The highest prism which can permit single vision gives the verging power. This is tested in different directions . INTERPRETATION The normal converging power varies a great deal .It can be raised to 50 degrees(25 D).If it falls to below 10 D it is definitely insufficient. The normal diverging power should be 2.5D