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The blind spot indicates the location of the optic nerve head—an area with no photoreceptors—in the temporal part of the visual field. Anything obstructing the travel of light towards the retina may affect the field tests, for example, lens opacity (cataract), ptosis (if not taped away from the pupil) or the rim of a correcting lens (test ...
- Sui H Wong, Gordon T Plant
- 2015
- Gather Equipment
- Introduction
- Visual Acuity
- Colour Vision Assessment
- Visual Fields
- Blind Spot
- Inspection of The External Eye
- Pupillary Reflexes
- Assessment of Strabismus
- Eye Movements
Gather the appropriate equipment: 1. Snellen chart 2. Ishihara chart 3. Fine print reading chart 4. Pinhole 5. Hatpin 6. Ophthalmoscope 7. Pen torch 8. Mydriatic eye drops
Wash your hands and don PPEif appropriate. Introduce yourself to the patient including your name and role. Confirm the patient’s name and date of birth. Briefly explain what the examination will involve using patient-friendly language. Gain consentto proceed with the examination. Position the patient sitting on a chair. Ask if the patient has any p...
Assessment of visual acuity
Begin by assessing the patient’s visual acuity using a Snellen chart. If the patient normally uses distance glasses, ensure these are wornfor the assessment. 1. Stand the patient at 6 metres from the Snellen chart. 2. Ask the patient to cover one eye and read the lowest line they are able to. 3. Record the lowest line the patient was able to read (e.g. 6/6 [metric] which is equivalent to 20/20 [imperial]). 4. You can have the patient read through a pinhole to see if this improves vision (if v...
Further steps for patients with poor vision
If the patient is unable to read the top line of the Snellen chart at 6 metres(even with pinhole) move through the following steps as necessary: 1. Reduce the distance to 3 metres from the Snellen chart (the acuity would then be recorded as 3/denominator). 2. Reduce the distance to 1 metre from the Snellen chart (1/denominator). 3. Assess if they can count the number of fingers you’re holding up (recorded as “Counting Fingers” or “CF”). 4. Assess if they can see gross hand movements (recorded...
Assessment of near vision
Assess the patient’s near vision using a near vision chart. If the patient normally uses reading glasses, ensure these are wornfor the assessment.
Colour vision can be assessed using Ishihara plates, each of which contains a coloured circle of dots. Within the pattern of each circle are dots which form a number or shape that is clearly visible to those with normal colour vision and difficult or impossible to see for those with a red-green colour vision defect.
This method of visual field assessment relies on comparing the patient’s visual field with your ownand, therefore, for it to work: 1. you need to position yourself, the patient and the target correctly (see details below) 2. you need to have normal visual fields and a normal-sized blindspot
A physiological blind spot exists in all healthy individuals as a result of the lack of photoreceptor cells in the area where the optic nerve passes through the optic disc. In day to day life, the brain does an excellent job of reducing our awareness of the blind spot by using information from other areas of the retina and the other eye to mask the...
Inspection of the external eyes including the anterior segment can provide a lot of valuable clinical information. See our anterior segment examination guidefor a more detailed approach.
With the patient seated, dim the lights in the assessment room to allow you to assess pupillary reflexeseffectively.
Light reflex test
1. Ask the patient to focus on a target approximately half a metre away whilst you shine a pen torch towards both eyes. 2. Inspect the corneal light reflex on each eye: 1. If the ocular alignment is normal, the light reflex will be positioned centrally and symmetrically in each pupil. 2. Deflection of the corneal light reflex in one eye suggests a misalignment.
Cover test
The cover test is used to determine if a heterotropia (i.e. manifest strabismus) is present. 1. Ask the patient to fixate on a target (e.g. light switch). 2. Occlude one of the patient’s eyes and observe the contralateral eye for a shift in fixation: 1. If there is no shift in fixation in the contralateral eye, while covering either eye, the patient is orthotropic (i.e. normal alignment). 2. If there is a shift in fixation in the contralateral eye, while covering the other eye, the patient ha...
Briefly assess for abnormalities of eye movementsthat may be caused by underlying cranial nerve palsy (e.g. oculomotor, trochlear, abducens, vestibular nerve pathology). 1. Hold your finger (or a pin) approximately 30cm in front of the patient’s eyes and ask them to focus on it. Look at the eyes in the primary position for any deviation or abnormal...
Jan 1, 2018 · If appropriate, map out the patient's blind spot: the patient and examiner are seated as for the visual field test. both close one opposite, non-tested eye.
13 Using a red hatpin (or alternatively, a cotton bud stained with fluorescein/pen with a red base) start by identifying and assessing the patient’s blind spot in comparison to the size of your own.
Ask the patient to focus on a red hat pin presented directly in front of their eye. Move a hat pin of a different colour (or white cotton swab) temporally until they lose sight of it. Ensure these are midway between yourself and the patient so that you are checking your blind spot and comparing it to theirs at the same time
A blind spot is a small area in the back of the eye where there are no rods and cones, making it insensitive to light. Find out how to measure your own blind spot and test your range of vision with this lesson and activities.
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Oct 9, 2024 · A temporary blind spot could mean the onset of a migraine headache. Or, a more serious health issue may be contributing to vision loss. If you notice a blind spot, call your eye doctor and schedule an appointment immediately.
