PRACTICAL APPROACH TO FUNDOSCOPY NELSON.R.MANDELA SCHOOL OF MEDICINE 2012
For this module, you need to be able to examine the fundus – on a model or a simulated patient - know the features and significance of papilloedema, and be able to recognise it clinically. You should also become familiar with other common abnormalities such as optic atrophy, hypertensive and diabetic retinopathy and retinitis pigmentosa – look at illustrations in your textbooks eg Talley Page 299 Note that we also have panoptic as well as standard ophthalmoscopes available in the Skills Lab. You must, however, be competent in the use of the standard opththalmoscope. LEARNING OUTCOMES:
a OPTHALMOSCOPE
Explain the procedure to the patient. Dim the lights in the room. To examine the right eye, you must: Sit on right side of the patient. Use your right eye to look into the patient’s right eye. STEPS:
Turn the ophthalmoscope on. Rotate the rheostat to the desired light output . You may start at full illumination and reduce it to a level that is comfortable to the patient. Select 0 on the lens dial. (If you wear spectacles, remove these and use the ophthalmoscope to correct your vision by focusing on an object 3-4 metres away and selecting the lens which provides the best focus for you) Select the correct aperture You may start with the small aperture and lower light intensity to avoid patient discomfort, but ultimately use the largest possible aperture for good viewing of the retina. STEPS ( cont )
• Hold the ophthalmoscope in your right hand, vertically in front of your right eye. • Place your index finger on the lens dial to enable you to change lenses easily in order to focus. • Instruct the patient to look straight ahead and focus on an object in the distance. STEPS ( cont )
• Place your left hand on the patient’s forehead, using your left thumb to hold the patient’s right upper eyelid open. • Position the ophthalmoscope +/- 15cm away from and 25 degrees to the right of the patient. • Direct the light beam onto the pupil as you move towards the eye. STEPS ( c ont )
• The red reflex should appear as you look at the pupil. • Keep the reflex in view, as you move slowly closer to the patient’s eye. • When you are +/- 5cm away from the eye, the optic disc should come into view (or locate and follow a large retinal vein back towards the disc - all vessels radiate from the optic disc.) STEPS ( cont )
Rotate the lens dial until the optic disc is focused clearly. (Red numbers/negative numbers in myopia or short-sightedness. Green numbers/positive numbers in hyperopia or far-sightedness.) Examine the optic disc for: Shape – normally round or slightly oval Clarity of the outline-clear outline or rim Colour-rich yellow contrast to rich red of rest of fundus Elevation –disc is a shallow (physiological) cup Condition of vessels STEPS ( Cont )
Follow each vessel as far to the periphery as you can Ask the patient to look up, down, temporally and nasally and move as necessary as well to examine all areas of the retina, making sure to examine all 4 quadrants. The procedure is made difficult if the light is reflecting off the patient’s cornea, into your eye (corneal reflection). Use the appropriate filter (crossed polarising filter) to reduce this reflection. STEPS ( cont )
Examine the macula last. To locate the macula, focus on the disc, then move 2 disc diameters temporally. The macula is darker in colour than the surrounding fundus, and devoid of blood vessels. You may also ask the patient to look at the light. This automatically puts the macula into full view. STEPS ( cont )
Do the opposite to examine the patient’s left eye. STEPS ( cont )
1)The optic disc 2)The retinal blood vessels 3)The periphery of the fundus 4) The macula (Assess the vessels and look for other abnormalities such as hypertensive or diabetic retinopathy.) FUNDUS EXAMINATION: