The document outlines the first three points of a 21-step clinical refractive procedure, focusing on ophthalmoscopy, keratometry, and the habitual phoria test. It details methodologies, purposes, and types of ophthalmoscopy, as well as the significance of keratometry in measuring corneal curvature and astigmatism. In addition, it describes the procedure for testing habitual phoria, emphasizing the importance of accurate measurements for optimal patient outcomes.

1. 1. OPHTHALMOSCOPY
2. KERATOMETRY
3. HABITUAL PHORIA TEST
DX
GROUP 1
202135070 NXUMALO N
202124124 SWANEPOEL W
202105522 PHOLOANA BE
202137445 MAVECUA SP
202124919 MASHELE R

2. TODAY, WE WILL BE DISCUSSING THE FIRST THREE POINTS OF THE 21-STEP
CLINICAL REFRACTIVE PROCEDURE.
REFRACTION IS A COMPLEX PROCESS THAT INVOLVES NUMEROUS STEPS TO
ENSURE OPTIMAL OUTCOMES
FOR PATIENTS. THE 21-STEP CLINICAL REFRACTIVE PROCEDURE IS A
COMPREHENSIVE GUIDE FOR OPTOMETRISTS TO FOLLOW TO ACHIEVE THE
BEST POSSIBLE RESULTS FOR THEIR PATIENTS.
INTRODUCTION

3. OPTHALMOSCOPY
1. What is ophthalmoscopy
2. what is the purpose of
perfoming it
3. Content
-Instrumentation
understanding
-Procedure/Methodology
-Normal values
-recording

4. Ophthalmoscopy is an examination of the back part of the eye
(fundus), which includes the retina, optic disc, choroid. and blood
vessels. It can also be called Fundoscopy
1. OPHTHALMOSCOPY

5. - To determine the presence or absence of pathology
-Ophthalmoscopy is performed as part of a standard physical
examination or comprehensive eye exam.
-It is employed to identify and assess the signs of glaucoma or
retinal detachment.
- If you exhibit any indications or symptoms of high blood pressure,
diabetes, or other conditions that impact the blood vessels,
ophthalmoscopy may also be performed.
WHY THE TEST IS PERFORMED(PURPOSE)

6. Different types of ophthalmoscopy.
- Direct Ophthalmoscopy
- Indirect Ophthalmoscopy
- Telescopic Ophthalmoscopy

7. • Direct ophthalmoscope is a handheld
instrument used to examine the Fundus
• It is used monocularly.
• It can be used to examine central 7 to
10 degree of retina
• It gives a magnification of 15x which
makes the 1.5mm disc appear much
larger
DIRECT OPHTHALMOSCOPE

8. Practitioner’s side Patient’s side

9. Aperture Sizes
• The Large aperture is used for a dilated pupil after administering mydriatic drops.
• The medium aperture is the standard for a non-dilated pupil in a dark room
• The small aperture is for a constricted pupil in a well-lit room.
Light Filters
•Red free: Used to look closely at the vasculature.
•Blue: Used to look for corneal abrasions or ulcers with fluorescein dye.
•Slit : Used to look at contour abnormalities of the cornea, lens or retina.
•Grid: Used to approximate the relative distance between retinal lesions.
DIFFERENT LIGHT SETTINGS ON THE
OPHTHALMOSCOPE

10. • Wash your hands first.
•Introduce yourself and explain the test to your patient
•Place the patient so that their eyes are directly above the level of the ophthalmoscope.
•Switch on the ophthalmoscope and adjust the light's aperture.
•Lower the lighting.(preferably dark ,so that the pupils can dilate)
•Tell the patient to concentrate on target directly in front of them.
•Hold the ophthalmoscope in your RIGHT hand and gaze through it with your RIGHT eye to
examine the patient's RIGHT eye.
•Position your ophthalmoscope 15 degrees to the right and above 15 cm from the eye.
•Locate your red reflex.
METHODOLOGY OF DIRECT OPHTHALMOSCOPE

11. •Get closer and maintain a nasal position until you can view the optic disc
Once at disc, clear it and observe:
◦ Margins (distinct/ indistinct)
◦ Rim tissue (colour) – ISNT rule
◦ Cup margins (look at kinking of vessels for border and not pallor
◦ Cup size (C/D ratio)
◦ Cup depth (deeper = brighter yellow)
◦ Visibility of lamina cribrosa
-The nearsighted eye need more minus/red whereas the farsighted eye needs more
plus/green number lenses.
•Slightly scan to the left, right ,up and down to examine the vessels.
•Extend temporally to locate the fovea and macula.
•Use the identical procedure on the other eye.

12. Describe the structures seen in the eye especially any
abnormalies
Example of normal eye Disc
• margins are sharp/distinct
•Colour: yellowish orange to creamy white
•Shape: round or oval
•Cup to disc ratio: less than half
RECORDING RESULTS FOR OPHTHALMOSCOPY

13. Vessels
•AV ratio
• AV crossing: No indentation
• No arterial light reflex
Fundus background
• No exudates
• colour: red to purplish
Macula
• macula is located 2.5 disc distance temporal to disc
• no vessels are noted around Macula
• it may be slightly pigmented

15. ABNORMALITIES

16. RECORD CARD

17. • Indirect Ophthalmoscopy – An examof the inside of back of the eye
using a beam of light and hand-held lens.
It is valuable for diagnosis and treatment of retinal tears, holes and
detachment.
-Binocular
Two types
-Binocular Indirect Opthalmoscopy
-monocular Indirect Opthalmoscopy
INDIRECT OPHTHALMOSCOPE

20. •Adjustment of the ophthalmoscope
•Adjust headband crown
•Adjust the pupillary distance
•Check illumination intensity. Usually start with lower illumination and slowly
increase illumination as needed and as tolerated by the patient. Check for a
proper elevation/position. Check can be done by extending arm or by
looking at a wall.
•Apply filter if desired
•Positioning the patient - Patient should be in a supine position
METHODOLOGY OF INDIRECT
OPHTHALMOSCOPY

21. •Patient should be looking directly up, initially (primary position)
•Examiner should initially stand to the side of the patient, leaning over
the patient
•Keep handheld lens approximately 2 inches away from patient's eye,
moving it closer or farther away to focus and refine the view
•Examiner swivels his view around to view different parts of the retina,
by tilting the head and walking around the patient
•The doctor instructs the patient to look at various extremes of their
vision
•The macula is examined at the last, as the light is bright and patient
cooperation for BIO may reduce drastically if macula is examined at the
initiation of BIO

22. - it enables stereo vision- binocular vision with the ability to
perceive depth
- It has a wider field of view.
- It is not affected by the refractive state of the eye.
- It can hold a bigger, brighter light source, allowing the
examiner to see more detail in the retina pass through
moderate cataracts.
ADVANTAGES OF BINOCULAR INDIRECT
OPHTHALMOSCOPY

23. MONOCULAR INDIRECT OPTHALMOSCOPY
Instrument:
 Magnifying eyepiece
 Relay system re-inverts image to a real
one
 Image is focused using eye piece
Indication of use:
• Small pupils
• Uncooperative children
• Patients intolerant to bright illumination

25. KERATOMETRY
Keratometry (K) is the
measurement of the corneal
curvature; the corneal curvature
determines the power of the
cornea. Astigmatism results from
differences in power across the
cornea (opposite meridians);
thus, keratometry measures
astigmatism.

26. • Assists in calculating corneal astigmatic error
• Aids in contact lens fitting by estimating the radius of corneal
surface curvature.
• Evaluates corneal shape: Keratoconus
• Evaluate refractive error when dealing with foggy media.
• Calculation of Intra Ocular Lens power.
• To check astigmatism before and after surgery.
• Used to distinguish between axial and curvature anisometropia.
KERATOMETRY PURPOSE

27. Keratometers
Fixed Doubling
• bausch and Lomb, Topcon and Mognon
• Variable-Image size and mire separation
• Fixed –object height and doubling device
distance
Variable Doubling
• Haag Streit, Javal Schiotz
• Variable –object height and doubling
• Fixed-image size and mire separation

28. One position Keratometer
• Double images are produced side by side as
well as at 90 from each other.
• The principle meridians are assumed to be at
right angkes to each other
Two Position Keratometer
• Require rotation about the axis to measure
each of the principle meridians

29. Javal Schiot Bausch and Lomb
;

30. KERATOMETRY METHODOLOGY

31. Seat Patient infront of instrument
•Chin on chin rest & head against head rest.
•Eye not being examined is covered with occluder.
•Chin raised or lowered till patient's pupil & projective knob are at the same level.
Instruct the patient to :
• Keep eyes open wide and blink normally.
•Try not to move the head nor speak.
•Look at the reflection of own eye in the keratometer barrel
METHODOLOGY CONT…

32. • Adjust to align
the mires like
image shown and
record the
measurements

33. •K1
•KF (k flat )
•Curvature power of the flat meridian of the anterior surface of the cornea
•measured within the 3-mm central zone expressed in diopters (D).
•Normal K1 is > 34 D.
•In myopic correction each - 1 D correction reduces flat K by 0.75 D to 0.8 D.
•Final flat K should be > 34 D to avoid spherical aberrations with bad vision quality even with
post-treatment zero refraction
• K1 should be calculated using the axial curvature method rather than tangential one.
KERATOMETRY READINGS

34. •K3
•Ks (k steep)
•Curvature power of the steep meridian of the anterior surface of the cornea
•measured within the 3-mm central zone
•expressed in diopters (D).
•Normal K2 is < 49 D.
•In hyperopic correction each + 1 D correction will add 1.2 D to steep K.
•Final steep K should be < 49 D to avoid spherical aberrations with bad vision quality
even with post-treatment zero refraction
• K2 should be calculated using the axial curvature method rather than tangential one

35. •KM
•K-average
• Mean curvature power of the anterior surface of the cornea
•Measured within the 3-mm central zone
•Expressed in diopters (D).
•Considered to avoid flap complications.
•Km is should be > 40 D to avoid free-flap
•Km should be < 46 D to avoid button-hole complication.

36. •КМАх
•Maximum curvature power of the whole anterior surface of the cornea
•Expressed in diopters (D)
•Normal Kmax is < 49 D
•The normal difference in Kmax between the two eyes is < 2 D
•The normal (Kmax-K2) difference in the same eye is < 1 D.
•Whenever the difference between kmax and K2 is 2 1D, K-max should be used
instead of K2 for Hyperopic correction to avoid spherical aberrations with bad
vision quality even with post-treatment zero refraction
•K-max should calculate using the axial curvature method rather than the
tangential one.

37. Topographic astigmatism (TA)
•The difference between K2 - K1
•Within the 3-mm central zone
•TA should be compared with manifest astigmatism (MA).

38. •Done at far and near
•Test done is called Von Graefe
•Dissociates eyes by means of vertical and horizontal prisms
•Measures vertical and horizontal relative position of visual axes when fusion is
broken.
•Measures innervation of muscles at certain distance
•Only for Horizontal Phoria
HIBITUAL PHORIA TEST

39. •Test distance is at 6m
•Target is best VA on distance Snellen chart
•Room illuminated
•Old prescription lenses placed in phoropter
•Prisms placed in OD 10BI and OS 6 BU
•Instruct patient to respond when images are vertically aligned
•Reduce BI prism until targets are aligned and record results.
METHODOLOGY

40. Results are recorded as BI or BO
BI= Exophoria
BO= Esophoria
Normal Value should be Less than 0.5 Exophoria
RECORDING RESULTS

41. 1.https://www.meddean.luc.edu/lumen/meded/medicine/pulmonar/pd/pste
p16.htm
2.https://link.springer.com/chapter/10.1007/978-3-030-35340-7 8
3.
REFERENCES