Clinical Optometric Procedures: Ocular Health Examination

Clinical Optometric Procedures: Ocular Health Examination

SECTION C – OCULAR HEALTH EXAMINATION

• This section includes a review of:
• Tests included in assessment of ocular health
• Direct ophthalmoscopy
• Normal fundus
• Diagrammatic representation of the various structures of the fundus

INTRODUCTION

Anectodal reports reveal that most practitioners assume that an assessment of ocular health involves a posterior segment evaluation of the fundus. The ocular health examination reveals information on the current status of ocular health, conditions that have the potential to result in ocular damage and to monitor the effect of systemic disease on the ocular system. The effects of systemic disease is not only limited to an assessment of the posterior segment of the eye, but involves assessment of pupils, visual fields, binocularity, etc.

TESTS USED FOR ASSESSMENT OF OCULAR HEALTH

Assessment of ocular health should include tests such as:

1. Pupillary responses (which can also be performed as part of the preliminary examination) 2. Evaluation of the anterior segment and adnexae (may be achieved by direct observation and slit lamp biomicroscopy

3. Evaluation of ocular media (achieved by slit lamp biomicroscopy, direct ophthalmoscopy, visual acuity) 4. Evaluation of the posterior segment. An assessment of the posterior segment may be achieved by several methods of examination, namely:

• a. Direct fundus examination (direct ophthalmoscopy)
• b. Dilated fundus examination
• Stereoscopic fundus biomicroscopy
• Binocular indirect ophthalmoscopy

5. Visual field screening (confrontation) 6. Measurement of intraocular pressure (this may be achieved by using non-contact and contact methods of measurement)

7. Systemic health screening tests

We shall describe now the techniques used for the assessment of ocular health in more detail:

• 1. Pupillary responses
• This has been discussed in Section A Chapter 7 of the preliminary eye examination.
• 2. Evaluation of the anterior segment and adnexae

1. This may be achieved by gross direct observation or with the slit lamp biomicroscopy 2. Gross observation of the patient’s body, face and head must take into consideration. These observations provide clues regarding the visual, ocular and general health issues involved o Body positioning: this could provide information about the presence or evidence of a stroke o Head turn, tilt or elevation could indicate extraocular muscle difficulties, visual field problems and possible ocular pathology (like ptosis or macular degeneration) leading to compensatory head position changes

o An assessment of the external ocular structures, i.e. the eyelids, eyelashes, puncta, conjunctiva, cornea and iris. Some of these structures can be observed with the naked eye, with extra light and slight magnification (+10.00DS lens or Burton lamp) or with a slit lamp biomicroscope.

3. In addition to the gross observation of the external ocular structures, the practitioner can also make an assessment of the anterior chamber angle width in the absence of other instrumentation such as a slit-lamp or gonioscope or when these techniques cannot be performed like in the paediatric population. This method of examination is also referred to as the Shadow method.

• Procedure

o Direct the patient to a distance target in primary gaze o The practitioner holds a penlight temporal to the eye at about 15cm from the eye so that the penlight lies in line with the pupil (Fig. 1a). To achieve an accurate positioning of the penlight, the practitioner can begin by placing the penlight behind the eye/head position and then move it anteriorly until the practitioner is able to observe the illumination of the iris surface (Fig 1b).

Figure 1 Positioning of the penlight for the shadow method of anterior chamber angle width estimation o The tangential illumination source (Fig. 2) will allow the practitioner to observe a crescent shaped shadow on the iris area opposite to the position of the penlight (Fig. 3) when the patient’s eye is in primary gaze International Centre for Eyecare Education Figure 2 Illumination of the iris surface with the temporal tangentially placed penlight o The crescent-like shadow observed is produced by the elevation of the iris on the side of the penlight illumination, thus preventing the light from passing across the entire iris surface unobstructed (Fig. 3a). The width of the crescent-like shadow will vary depending on the width of the anterior chamber angle. If the practitioner notices no shadow created (Fig. 3b), then it would indicate that there is a deep anterior chamber depth and therefore a lesser chance of the presence of angle closure glaucoma or a lesser chance of precipitating angle closure glaucoma with dilated fundus examinations.

Figure 3 (a) Grade 2 anterior chamber depth (risk of angle closure); (b) Grade 4 anterior chamber depth (open angle)

o The grading of the anterior chamber angle depth and its likelihood to precipitate an angle closure is illustrated in figure 4. These guidelines are used to complement practitioner sketches in an effort to allow the practitioner to grade angle depth.

Grade 4 Grade 3

• Angle closure is unlikely – Dilation possible

Grade 2 Grade 1

Dilation maybe risky Dilation is contraindicated Figure 4 Grading scale used for the classification of the anterior chamber angle depth based on LOCS III photographs International Centre for Eyecare Education 3. Evaluation of ocular media

• The ocular media comprises the cornea, anterior chamber, crystalline lens and vitreous body.
• The main feature of the ocular media is that they should be transparent. The purpose of the ocular health

examination to assess the transparency of these structures. The practitioner shines the direct ophthalmoscope light into the eye and observes the light reflected from the retina. This is observed as a red glow within the pupil area, referred to as the red reflex. A lack of transparency is inferred when there is an obstruction in the light returning back through the pupil which is observed as a shadow. In addition, the red glow returning from both eyes should similar. A lack of similarity could indicate the presence of subtle media opacities.

• In addition, an asymmetrical brightness of the reflex between the 2 eyes may indicate the presence of

strabismus, or anisometropia where the eye with the abnormality is brighter eye. This is referred to as the Brückner test. It is a valuable objective assessment of ocular alignment or refractive status in patients where the practitioner may receive limited subjective feedback. This will be discussed in much more detail in the binocular vision module.

• When assessing the ocular media using the ophthalmoscope, it may be necessary for the practitioner to vary

the focus by rotating the lens wheel to a more plus power to focus on the more anterior structures of the eye.

• When observing corneal abnormalities with direct examination, it usually will appear white instead of as a
• black shadow obstructing the red reflex.

4. Evaluation of the posterior segment

• An assessment of the posterior segment may be achieved by several methods of examination, namely:
• a. Direct fundus examination (ophthalmoscopy)
• b. Dilated fundus examination
• Stereoscopic fundus biomicroscopy
• Binocular indirect ophthalmoscopy
• For the purposes of the scope of this course, direct ophthalmoscopy will only be discussed. The other
• methods of examination will be discussed in Clinical Optometry II course.
• 5. Visual field screening (confrontation)
• Discussed in preliminary examination.

6. Measurement of intraocular pressure

• The measurement of intraocular pressure may be achieved by non-contact and contact methods.

7. Systemic health screening tests

• Besides direct opthalmoscopy providing the practitioner with information regarding the systemic health of the

patient, other tests like blood pressure measurements, carotid auscultation, etc. will be discussed in the Clinical Optometric Procedures II module.

DIRECT OPHTHALMOSCOPY

Purpose of Direct Ophthalmoscopy

Direct ophthalmoscopy provides a view of the posterior pole region of the fundus which includes the optic nerve and its vascular arcades and the macula.

The method of direct ophthalmoscopy has various advantages and disadvantages in its use in the ocular health examination.

• Advantages
• Easier to conduct than other methods of posterior segment evaluation
• Performed upright on patients allowing for more comfort
• Can be performed on large or small pupils
• Provides a relatively higher level of magnification ~15X
• Allows the assessment of media

 Portable/Handheld

• Upright image
• Disadvantages
• Lack of stereoscopic view of the posterior segment
• Close working distance
• Provides a small field of view
• Produces distortion with off-axis views of the eye
• Limited views of media opacities are present
• Parts and Optics of the Direct Ophthalmoscope
• Parts of the direct ophthalmoscope
• Rheostat to control illumination
• Variable Aperture sizes small to large- Varying diameters (pupil size adjustment)
• Lens power indicator (plus and minus)
• Auxiliary controls:

o Red-free filter is used to differentiate retinal and choroidal lesions, hemorrhages, pigment, subtle optic nerve head drusen and nerve fibre layer defects o Fixation cross is used to assess fixation and in some cases grade position and size of defects.

o Slit beam is used to detect elevated lesions on the fundus and macula holes (Watzke-Allen test) o Cobalt blue filter is used together with fluorescein on the cornea to assess corneal scar and abrasion as well as pupil size in the dark. International Centre for Eyecare Education Optics of the direct ophthalmoscope

Figure 5 Optics of the ophthalmoscope The direct ophthalmoscope comprises an observation system and illumination system. More recent changes in the illumination system have included a halogen light source which was introduced by Welch Allyn in 1973. Other improvements include optically coated lenses and prisms to reduce the amount of glare reflected into the practitioner’s eye. Auxillary features of the ophthalmoscope include: apertures of varying diameters, fixation and slit apertures, fixation target cross and various filters including the red-free filter, and cobalt filter.

• 1. Illuminating system
• Figure 6 Optics of the illuminating system of the direct ophthalmoscope
• The illumination system comprises:
• A tungsten bulb, condensor system, projection lens and reflector
• Bulb is centered and produces a filametic image on the reflector
• Can be filled with halogen gas  increase light output
• Reflectors can be either mirrors, metallic plates, prisms
• A range of aperture stops and filters are present between the condensing and projection lens
• The illumination system also Includes a series of different size apertures
• A series of filters are also part of the illumination system, viz. red free filter which increases the contrast

between vessels and retinal background, differentiates retinal and choroidal lesions, differentiates hemorrhages and pigment

• 2. Observation System:
• Figure 7 Optics of the observation system of the direct ophthalmoscope
• The observation system comprises:
• A sight-hole/peephole and focusing system
• A focusing system made of a rack of lenses
• Sight-hole positions the viewing axis to one side of illumination axis and so displaces the corneal reflex
• A bright corneal reflex can be eliminated by using a polarizing filter, however, it causes a loss of light

Procedure for Conducting Direct Ophthalmoscopy 1. The practitioner must grasp the ophthalmoscope such that his/her fingers are placed on the lens wheel which allows the practitioner to adjust lens power in either the plus or minus direction.

The right hand is used to hold the instrument when performing the technique on the right eye and by the left hand when performing on the left eye. Practitioners who have physical or visual limitations may not be able to adapt to this method of instrument handling.

2. The observation aperture of the ophthalmoscope must be directly before the practitioner’s eye, thereby requiring the practitioner to move his/her head, arm and ophthalmoscope as one unit.

3. Fixation and its maintenance is essential to performing a problem-free ophthalmoscopic examination on a patient. The patient must be directed to view in the primary or straight ahead position since the optic nerve head of the posterior pole is the structure that is observed first. One may provide a large fixation target on a VA chart to assist in this process or in the case of paediatric evaluation, an interesting visually stimulating distance target.

4. The technique is best performed in dimly lit room to ensure that the pupil size is maximal in size to encourage a larger field of view upon examination.

5. It is essential to provide the patient with adequate instructions. This would include the purpose of the test the bright light and that you are likely to come very closer to their eye or face. In this way, the patient is ready for you to invade their internal space.

6. When beginning the examination, the practitioner begins with approximately +10.00DS lens and positions himself/herself at about 10cm from the patient (equivalent to the focus of the +10.00DS lens). This lens power facilitates a view of the anterior media structures. One would be able to observe the red-reflex which is the reflection off the fundus. Any media disturbance would usually obstruct the view of this red-reflex. As the practitioner focuses towards posterior structures, i.e. aqueous, lens, etc, he decreases the power of the focusing lens.

7. The patient is usually not required to use their prescription unless he/she has a very high refractive error.

8. Media opacities are assessed using the principle of motion of parallax plus nodal point as reference.

a. If the opacity lies in the anterior capsule, then the opacity appears to move in the same direction as the movement of the eye

b. If the opacity lies in the posterior capsule, then the opacity appears to move in the opposite direction as the movement of the eye

c. If the opacity lies posterior to the lens, in the vitreous gel, usually floaters, they will appear to move as the patient moves his/her eye and then float back to the original position.

9. As the practitioner completes the examination of the media, he/she will be moving closer to the patient.

However, the practitioner should not get closer than the extent of the eyelashes.

10. Adjustments in the prescription used to view the eye may need to be calculated as per formula in order for the practitioner to be able to see the patient’s retina clearly. The power of the correcting lens must be the algebraic sum of the ametropias of the practitioner and the patient minus the dioptric amount of their accommodation.

For example: (-2.00 + 5.00) – 1.00 = +2.00DS 11. When the practitioner is ready to view the fundus and more specifically the optic nerve head (ONH), he/she may move to a position that is slightly temporal to a central view. At this point, the patient is observing along the visual axis. In some cases, it may be difficult for the patient to be able to obtain an immediate view of the ONH even in this position. If so, the practitioner must find a bifurcation of the vessel forms a “V” shape, which will give the practitioner a guideline as to which direction to move in order to find the ONH.

F correcting lens = (Examiner’s Ametropia+ Patient’s Ametropia) – accommodation International Centre for Eyecare Education 12. Once the practitioner reaches the ONH, there are several features that the practitioner would have to take cognizance of in order to determine the health status of the retina. These features include:

• Disc margin contour and distinctness
• Neuroretinal rim tissue. This lies between disc and cup margins and its pattern of width. This needs to

be observed carefully as it may be an indicator of risk of glaucomatous change occurring in patients.

• Cup-to-disc ratio (C/D ratio)- horizontal and vertical
• Depth of the cup
• Visibility of the lamina cribrosa
• Contour of the cup margins
• Crescents around disc margin
• Central retina artery (CRA) and Central retinal vein (CRV)
• Spontaneous venous pulsation
• Artery-to-vein thickness ratio (A/V ratio)
• Artery and vein crossings, which should be assessed away from ONH
• Arteriolar light reflex
• Other variations in vasculature which include circumlinear vessels, cilioretinal vessels, undermined

vessels, neovascularisation, etc.

13. The practitioner is required to examine all four quadrants. Either the practitioner will move towards the different quadrants or the patient looks in different directions of gaze.

14. Any abnormalities/lesions should be noted in terms of size, position from the disc in clock position.

15. The macula is examined by asking the patient to look into the light source of the ophthalmoscope, or the practitioner should move their view in a temporal direction to reach the macula. The practitioner must note the colour, any abnormalities, presence of a foveal reflex, steadiness of the position of foveal reflex with fixation and uniformity of the colouration of macula.

The assessment of ocular health using ophthalmoscopy cannot be achieved without the practitioner being aware of the normal fundus appearance and its variations.

NORMAL FUNDUS

• Colour of the Fundus
• There is variation in the background colour of the overall fundus between individuals.
• The background colour of the fundus is reddish-orange due to the pigment in the retinal pigment epithelial

layer (RPE), choroid and vasculature.

• In individuals with sparse pigment, like in Caucasians, the choroid vasculature is more visible and the fundus

therefore has a more red appearance.

• In individuals with dense pigment, like in Asians and African patients, the increased pigment content in the

fundus gives a tessellated or tygroid appearance which are observed as dark streaks of pigment Optic Nerve Head (ONH)

• The ONH lies nasal to the macula or can be observed most easily when the practitioner observes the retinal

when he is about 15 degrees temporally positioned relative to the eye being examined.

• The ONH dimensions on average: 5.5mm wide and 7.5mm wide. Its projection in the visual field is referred

to as the blindspot, since the ONH is devoid of photoreceptors.

• The outer margins of the ONH are indicated as the disc margin and should be clear and defined. A lack of

clarity of these margins may indicate the presence of pathological conditions.

• The central portion of the ONH is marked by an excavation which is referred to as the physiological optic

cup. It is the point of exit of the ganglion cell fibres from the retina into the optic nerve. The intraocular pressure tends to have an impact on the morphology of the cup and the neuro-retinal rim.

• An assessment of the C/D ratio is the size of cup relative to disc.

Retinal Vessels

• The blood vessels observed in the fundus is the only site in the body where they can be visualized directly.
• The veins are thicker, darker because they carry de-oxygenated blood. They have transparent walls.
• The arteries are narrower and brighter red in colour.
• The CRA and CRV emerge at optic disc and enter the nerve fibre layer.
• Both arteries and veins have a relatively smooth path. Tortuoisty may be a congenital variation or indicate

the presence of vascular pathology.

• An assessment of the AV ratio (thickness of A compared to V) usually is conducted after the second
• bifurcation of the vessels. The normal A/V ratio is 1:2, 2:3.
• Macula
• The macula lies approximately 2 disc diameters (DD) temporal to the optic disc.
• Its area spans 5mm in diameter.
• Macula is darker in pigmentation than the rest of the fundus. This is attributed by;
• Increased pigmentation in the RPE layer
• Xanthophyll pigment giving the macula an orange/brown hue
• Macula pigment is uniformly distributed.
• Abnormalities of the macular pigmentation is usually observed as an uneven colouration and referred to as
• being mottled.
• It is area of the fundus that is rich in retinal cone photoreceptors.
• The central region of the macula is known as the fovea centralis (foveal avascular zone). It is an area that is

very slightly excavated relative to the surrouding area of the macula. It gives rise to a foveal reflex when illuminated as it is a thinner aspect of the macula.

• Foveal avascula zone (center portion of macula) is entirely dependent on the choriocapillaries for its nutrition

and O2 supply. International Centre for Eyecare Education The above mentioned structures are discussed in greater detail in its diagrammatic representation.

DIAGRAMMATIC REPRESENTATION OF THE VARIOUS

STRUCTURES OF THE FUNDUS

• 1. Disc margins of the ONH
• 2. Neuroretinal rim tissue between disc and cup margins
• 3. Cup-to-disc ratio (C/D ratio)
• 4. Depth of the cup
• 5. Visibility of the lamina cribrosa
• 6. Contour of the cup margins
• 7. Crescents around the disc margin
• 8. Central retina artery (CRA) and Central retinal vein (CRV)
• 9. Spontaneous venous pulsation
• 10. Artery-to-vein thickness ratio (A/V ratio)
• 11. Artery and vein crossings

12. Arteriolar light reflex

13. Other variations in vasculature which include circumlinear vessels, cilioretinal vessels, undermined vessels, neovascularisation, etc.

• 1. Margins of the Cup or Disc
• Optic disc
• Optic disc size:
• The optic disc (OD) is not constant among individuals
• According to Jonas et al (1999)
• OD in men > women
• high myopia > high hyperopia
• OD varies with race, with White/Caucasians < Asians/Hispanics < African-American
• Optic disc diameter:
• ~ 5 wide horizontally and ~7 wide vertically.
• Fig 8 Dimensions of the optic nerve head

Optic disc shape:

• The OD is slightly vertically oval. On average, vertical diameter being about 7-10% larger than the horizontal
• Not uncommon to find spherical ODs
• Abnormal disc shapes may be correlated with increased corneal astigmatism

Disc margins:

• The scleral crescent is the limit of the disc and may appear as a partial or total white circle peripheral to the
• normally pink neuroretinal rim (NRR)
• Margins of the disc may be either distinct or indistinct
• Margins may be elevated or blurred. Examples of cases presenting with blurred disc margins are: ONH

drusen, benign intracranial hypertension, advanced systemic hypertension, etc. When this occurs, it is necessary to distinguish them from a normal variation or pathology

• The symbols used to denote the margins of the disc are:

Distinct contour Indistinct contour

Figure 9 Normal optic nerve head – (a) scleral rim is indicated between arrows; (b) distinct optic disc margin

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• Optic cup (OC)
• Optic cup size in relation to the Optic disc size
• The optic cup is the excavation of the ONH
• The border between the OC and the NRR is determined by contour and not pallor (this is best achieved by
• stereoscopic examination of the ONH)
• The border of the cup may be determined by locating the contour of vessels (Fig. 13)
• Cup is larger in a larger optic nerve head but C/D ratio is relative to ONH size

Figure 13 Contour changes to the vessels (indicated by arrows) indicates the margin of the optic cup 2. Neuro-Retinal Rim (NRR)

• Neuroretinal rim size
• This is the pink ring of capillary-rich tissue present on healthy optic nerve heads.
• It is the intrapapillary equivalent of the retinal nerve fibres and ON fibres.
• NRR assessment is necessary in ophthalmoscopic evaluation of the ONH.
• The NRR size is correlated with disc area. A larger disc has a tendency to have a larger NRR.
• Axons of the ganglion cells closer to the optic disc lie more centrally in the disc compared with axons from
• the retinal periphery which lie at the ONH margins.

NRR shape

• NRR shape is based on the vertically oval shape of the OD and the horizontally oval shape of the optic cup
• NRR is usually broadest Inferiorly, followed by Superior disc margin, Nasal disc area and finally the
• Temporal disc region (the “ISNT rule” as termed by Werner) (Fig. 14)
• NRR pallor may be a sign of ON damage
• Notching of the cup or vertical elongation of the cup indicates compromise to the nerve fiber. Assessment of

the NRR will show narrowing or thinning in this aspect of ONH. Assessment of this on visual fields is critical and may present with a visual field defect. International Centre for Eyecare Education

• The change in size and thickness of the NRR (Review rule of ISN”T) is of utmost importance in the diagnosis
• of early glaucomatous ONH damage, which may show up before visual field defects
• Figure 14 Comparisons of the neuroretinal rim indicating that the ISNT rule is satisfied
• 3. Cup-to-Disc Ratio (C/D)
• C/D ratios are dependent on the size of the OD and OC
• The estimation of the C/D ratio is independent of the magnification of the optic media and the method of

examination of the ONH

• Physiological cupping usually indicates a large C/D ratio (> 0.5) but no functional damage (i.e. visual field

loss)

• Asymmetric C/D ratios that differ by 0.2 or more between the 2 eyes is usually suggestive of glaucoma or
• other pathology
• The red free filter is helpful when judging the C/D ratio and macula
• To determine the C/D ratio, the disc diameter is designated a value of 1.0 or 10
• One must determine what the ratio is between the horizontal and vertical diameter of the cup to the
• horizontal and vertical diameter of the disc
• Both horizontal and vertical axes are specified (e.g. 0.4HX0.5V)
• The C/D ratio may be given as a decimal form (e.g. 0.5) or a percentage ratio (e.g. 50%)
• Methods of determining the CD ratio

a. Fitting the cup within the disc diameter One can estimate the CD ratio by estimating how many times the cup can fill the diameter of the disc. In the diagram below, the cup can fit into the diameter of the disc 3 times and there still some NRR that cannot be accommodated. This means that the CD ratio is approximately 0.3 along the horizontal and 0.3 vertical dimensions. C/D = 0.3HX0.3V

• Figure 15 Diagram of how to determine the CD ratio

b. Ruler method

Another method is to divide a disc into 10 parts across the diameter of and determine how many of those 10 divisions is occupied by the cup (Fig. 16). e.g. 4 parts of the 10 along the horizontal axis is filled by the cup making the CD ratio along the horizontal 0.4 or 40%. A similar procedure is followed to determine the vertical ratio.

• Figure 16 Diagram of how to use the rule method to determine the CD ratio
• 4. Depth of the Cup
• Cup depth can be either flat, moderate (sloping margins) or deep (steep margins).
• The depth of the cup may be inferred from the change in power to view the cup from the neuroretinal rim. A
• change in power of 3.00 DS = 1 mm depth
• A deep cup usually is one that may be associated with the presence of lamina cribrosa
• Abnormalities in the depth of the cup may be indicated by bean-pot cupping or baring vessels where
• circumlinear vessels were noted previously

5. Lamina Cribrosa

• The lamina cribrosa is a collagenous connective and glial tissue that is continuous with and bridges the

scleral canal.

• It is sieve-like tissue that provides support to the exiting ganglion cell nerve fibres.
• Visualized in about 35% of normal eyes as laminar dots at the base of the cup, i.e. they appear as greyish,

washed-out spots (Fig. 17).

Figure 17 (a) Direct schematic view of the lamina cribrosa observed within the cup; (b) Profile of the ONH and the lamina cribrosa in relation

• The lamina cribrosa is diagrammed by hash (#) signs or small circles (Fig. 18).
• It is generally more useful to diagram lamina with small circles. In conditions such as glaucoma, the lamina

may become distorted (change shape from round to elongated) following the direction of cup damage. This can be drawn as elongated.

• Normal lamina is diagrammed as while distorted lamina is diagrammed as . International Centre for Eyecare Education
• Figure 18 Diagrammatic representation of the lamina cribrosa and its distortion

6. Contour of the Walls of the Cup

• While the cup depth can be even in the entire cup, there are instances in which it can vary from one end of

the cup to the other.

• If the cup is deeper in one end and slopes at the other end, then it is indicated by oblique radiating lines (Fig.
• 19).

Figure 19 Radiating lines indicating sloping in a cup

• The contour of the cup in addition can also be judged by the turning of the blood vessels at the margin of the

cup. If the blood vessels make a sharp turn, then it indicates the cup contour is steep and if the blood vessels make a slight turn, then it indicates that the cup contour is sloping.

• 7. Margins of the Cup
• Margins of the cup are denoted in the same manner as that for the disc
• The symbols used to denote the margins of the cup are:

Distinct margin Indistinct margin

Figure 20 Diagrammatic representation of the sloping margins of a cup with indistinct margins as well 22 F 8.

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• Figure 22 (a) Schematic view of choroidal crescent (b) Schematic view of scleral crescent
• Figure 23 ONH with scleral and choroidal crescents

Figure 24 ONH with pigmentary crescent Peripapillary atrophy is also a crescent-like feature seen around the ONH (Fig. 25). It can be found in a 360 degree pattern around the ONH or more commonly observed temporally. The area of PPA can be divided into a peripheral alpha zone and central beta zone. The beta zone represents an area of total loss of the RPE and a reduction in the number of photoreceptors thereby increasing the visibility of the larger vessels of the choroid and the sclera. The alpha zone changes correspond to areas of RPE irregularities. The Beta zone is found more 22 F freque

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Artery and vein course

• In general, the caliber of the vessels should be uniform with no area of compression at the crossing of
• vessels
• 10. Spontaneous Venous Pulsation (SVP)
• Venous pulsation is found in about 80% of normal individuals
• It is an indication of the homeostatisis between blood pressure and intraocular pressure
• The incidence of a venous pulsation increases with age because of increase in IOP and increase in blood
• pressure
• Observing an SVP is recorded as positive or lack of it is recorded as negative.
• Venous pulsation can be either spontaneous (SVP)
• Conditions that can contribute to a venous pulsation from being seen or elicited include papilloedema, raised
• intraocular pressure – IOPs or very low blood pressure
• 11. Artery-to-Vein Thickness Ratio (A/V Ratio)
• The normal A/V ratio is approximately 2:3
• The A/V ratio is usually estimated beyond the second bifurcation
• Abnormalities that can alter the AV ratio include conditions such as diabetes and hypertension
• 12. Artery and Vein Crossings
• Compression of the veins with the arteries can occur at A/V crossings
• Merging of the arterial adventitia and venous glial coverings at A/V crossings. The sharing of tissue in this

area, result in compression of the vein wall when the arteries develop arteriosclerotic changes

• One may be able to observe the following A/V crossing changes:
• o Salus sign: a deflection of the underlying artery
• o Gunn’s sign: tapering of the artery invades or extends into the vein
• o Banking: distention of a vein peripheral to the crossing of the artery and vein

13. Arteriolar Light Reflex

• The arteriolar light reflex is the ratio width of the light that is reflected off the surface of an artery to the overall

width of the artery

• Thickening of the walls of the artery allows less light to pass through the artery. Therefore light reflected is
• greater, as in cases of arteriosclerosis or artherosclerosis
• The arteriolar light reflex is usually expected to be 1/3 or 1/4
• Arteriosclerotic changes involve a widening of the arterial reflex and narrowing of the vessels. This clinically
• appears white or copperish in color International Centre for Eyecare Education

14. Other Variations in Vasculature

• Other variations in vasculature include circumlinear vessels, cilioretinal vessels, baring of vessels,
• undermined vessels, neovascularisation, etc.

Cilioretinal arteries

• In rare cases the cilioretinal artery may be found nasally and does not branch off the CRA (Fig. 26a)
• The cilioretinal artery is a branch of the short posterior ciliary artery from the choroidal circulation (Fig. 26b)

and typically this vessel exits temporally towards the macula from the neuroretinal rim (Fig. 27)

• This artery is found in approximately 25% of population
• This artery may be one or on occasion 2 in number
• In a central retinal artery occlusion (CRAO) the cilioretinal artery can provide oxygen/nutrients of small

surface area of retina. If adjacent to the macula, in a CRAO can preserve a small amount of central vision Figure 26 (a) Shows direct view of the exit of the cilioretinal artery from the NRR (b) Shows the origin and path of the cilioretinal artery to supply the retina with blood in profile view Figure 27 ONH with cilioretinal artery Circumlinear vessels

• Circumlinear vessel is a vessel that follows the contour of the cup partially (Fig. 28).
• Circumlinear vessels may become barred (barring of vessel) when the cup enlarges. The neuroretinal rim
• narrows in cases of progressive glaucoma damage.

Figure 28 ONH with distinct disc margins, deep cup and a circumlinear vessel Circumlinear and cilioretinal vessels are diagrammed by a solid line which indicates the vessels origin, contour and position on the ONH.

Baring of blood vessels

• Baring is a blood vessel change that is observed when the NRR erodes at the edge of a blood vessel,

creating a separation between the vessel and the neural tissue (Fig. 29).

• Acccording to Vingrys (2000), blood vessels can appear bared by about 2 arterial widths and thereafter is it

considered abnormal.

• The significance of bared vessels may indicate progressive glaucomatous optic neuropathy, enlarged
• cupping (Fig. 30).
• Figure 29 ONH with bared vessel
• Bared blood vessel
• Circumlinear vessels International Centre for Eyecare Education
• Figure 30 ONH with a bared vessel

Undermined vessels (Kinking vessels)

• Undermined or kinked blood vessels occur when neural erosion in glaucoma produces different planes along
• the vessel path. It is sometimes also referred to as “bayoneting”.
• Undermined vessels are found in very deep cups which assume a “bean-pot” profile.
• The vessels are pushed significantly and their position is altered, usually by deepening and changes of cup

depth.

• The vessels start at one point, disappear and then reappear within the cup at another point.
• These vessels are diagrammed with 2 solid lines in the position at which they are undermined as in the
• diagram alongside.
• Figure 31 Example of a disc diagram for the retinal photograph
• Bared blood vessel International Centre for Eyecare Education
• Section D – MANAGEMENT PLAN
• This section will include a review of:
• SOAP format of record keeping

INTRODUCTION

Clinical decision making requires a practitioner’s ability for “clinical judgment, inference and diagnostic reasoning”.

All of these attributes stem most importantly, from close attention to patient reports and/or the case history. This is an aspect of the optometric assessment that is said to continue throughout the assessment and is not limited exclusively to the time dedicated to eliciting information for the case history. The second most important aspect of the assessment is the practitioner’s overall knowledge of all the facets of an optometric examination. These include knowledge of ophthalmic dispensing, occupational optometry, binocular vision, low vision, pharmacology and investigative techniques. By drawing on the information gathered, the practitioner is able to identify findings that account for patient symptoms. The practitioner is able to analyze these findings holistically and make decisions regarding a plan of action for the clinical and therapeutic management of the problems identified.

SOAP FORMAT OF RECORD KEEPING

The SOAP format is a formal system of record keeping that is used in the health care community and is not limited to the practice of optometry. It is adaptable to the wide scope of the optometric profession being easily usable also in sub-specialty areas of optometry such as contact lenses, low vision, sport vision.

The SOAP also facilitates the storage, retrieval & transfer of clinical information both inter- and intra-professionally.

This method allows for simple, complete and clear documentation of information in the patient’s records. Patient charts can be read easily and descriptive information can be obtained easily. Furthermore, it facilitates the computerization of clinical information, if available.

The SOAP format aids and displays the deductive clinical reasoning behind patient management and decision making process. The logic behind the diagnosis, treatment and management of clinical conditions is outlined explicitly for others to easily understand. When mastered, the SOAP form of record keeping adds a new dimension to the clinician’s knowledge about primary care and increases the quality of services.

• SOAP is the acronym which stands for:
• S = Subjective Comprehensive case history (information is obtained from the patient by
• the examiner)
• O = Objective Database of test results, clinical observations & findings (information

gathered by the examiner)

A = Assessment Diagnosis

• Differential diagnosis
• Rule-outs (could be in plan too)

P = Plan (Management) Treatment

• Follow-up

Monitoring

Consultation/Referral

Patient Education, or Advice, or Counseling The subjective & objective information are collected throughout the examination. The assessment is completed at the end of the subjective and objective findings. The assessment or diagnoses of all the pertinent and significant findings are listed. Each entity listed requires a plan (management).

• Example of an Assessment and Plan

1. Simple myopia OD + OS Prescription given to patients: (slight change from previous Rx)

OD-11.00 DS 6/6

OS -12.00 DS 6/6

• Patient education on change in Rx and to consider high index and

polycarbonate.

2. Retinal hole superior retina OD Patient education and information on risks of retinal detachment.

Refer to ophthalmologist for further assessment.

3. No diabetic retinopathy OD + OS Patient education on importance of an annual dilated eye examination (April 2009). Letter to be sent to primary care physician on findings.

Typically the first assessment is always the refractive diagnosis. Diagnosis is entered using qualifying & descriptive terms, not as data, for example, a diagnosis (Dx) is recorded as hyperopia, and the prescription of +1.00DS. Assessments also include the Differential Diagnosis and Rule-outs in cases of questionable diagnosis.

At the end of the record, signature of the examiner and date the examination was completed are required.

The assessments or diagnoses are noted and numbered separately.

Assessments made on each exam are also enumerated on a major problem list placed at the beginning of the patient’s medical record. This will also include the Patient’s systemic assessment made by other physicians.

Each assessment is noted with the same assigned number to allow for a rapid overview of the patient’s clinical history. The Plan is not indicated here. The major problem list only applies to problems pertaining to the primary eye care exam. As such problems related to another specific area of practice, e.g. contact lenses or low vision, would be reflected on other similar pertinent lists, e.g. contact lens overview or history list.

The Plan represents the response given to each assessment. Plans include management issues regarding treatment, follow-up, consultation, referral, education & advice. Plans are numbered to correspond to each assessment. The Plan includes 3 specific points: Diagnostic Measures (Dm), Treatment (Tx) and Patient Education (Pt.edu).

• Dm: Diagnostic measures (Dm) are future actions needed to acquire additional diagnostic information or to

secure the diagnosis. Dm are not always necessary.

• Tx: Treatment (Tx) includes therapeutic measures taken to address the diagnosis. Tx may include actions

such as follow-ups, consultation and refer

• Pt. Edu: Patient education (Pt. Edu) includes the information, advice & recommendations given to patients.
• Example of Soap Format Application

The following is an example of the SOAP format applied to a clinical case:

Subjective: A 50 year old male working in a car manufacturing plant presents with a complaint of poor vision when trying to assemble motor parts and when reading car part specifications. He also presents with a history of an occupational injury to his left eye.

• This aspect of the SOAP may include more information elicited from the patient during the
• case history.

Objective: Visual acuities:

Reduced uncorrected VA of the right eye at distance and near, with the near visual impairment being more debilitating than distance.

Refraction reveals:

Simple hyperopic astigmatism in the right eye and uncorrectable visual impairment in the left eye

Assessment / Plan:

• A1: Hyperopia/presbyopia OD
• P1: Tx: New Rx given –indicate the prescription in each eye with visual acuity
• Ed: 1st Bifocal, options discussed, FT bifocal advised.
• Polycarbonate lenses recommended for safety.
• A2: Traumatic Cataract OS, VA = LP
• P2: Dm: Return to clinic (RTC) for Laser Interferometry and pre-surgical A-scan
• Tx: Refer to ophthalmologist PRN as needed for surgical consult

Ed: Nature of cataracts, surgery options & prognosis