How to use an ophthalmoscope

The ophthalmoscope is a tool used by doctors to examine the retina and internal structures of the eye. This instrument may seem complicated to use, but it is actually quite simple if you know the correct steps.

In this article, we will guide you through the necessary steps to use an ophthalmoscope effectively and safely. You will learn how to prepare the patient, how to adjust the instrument for the best possible view, and how to interpret the examination results.

By following these steps, you will be able to use the ophthalmoscope with confidence and precision, providing accurate diagnoses to your patients.

Preparing the Ophthalmoscope

Before using the ophthalmoscope, it is important to properly prepare the instrument to ensure clear and precise vision of the ocular fundus. Here are the steps to follow:

Cleaning the Ophthalmoscope

Firstly, make sure that the ophthalmoscope is clean. Use a soft, dry cloth to remove dust and fingerprints from the outer surface of the instrument.

Brightness Adjustment

Next, adjust the brightness of the ophthalmoscope. Most ophthalmoscopes have a ring or button to adjust light intensity. Typically, it is recommended to start with low brightness and gradually increase until reaching desired level.

Lens Replacement

If necessary, replace the lenses of the ophthalmoscope. Some models allow you to choose between different lenses to suit the different needs of ocular fundus visualization. Check which lens is suitable for your purpose and replace it following the manufacturer's instructions.

Ophthalmoscope Placement

Finally, position the ophthalmoscope correctly. To do this, hold the instrument with both hands and position it about 15 cm away from the patient's eye. Make sure that the ophthalmoscope light is directed towards the patient's eye and that you can see the ocular fundus through the ophthalmoscope lens.

• Remove dust and fingerprints from the outer surface of the ophthalmoscope using a soft, dry cloth.
• Adjust the brightness of the ophthalmoscope according to your needs.
• Replace lenses if necessary to suit different needs of ocular fundus visualization.
• Position the ophthalmoscope correctly about 15 cm away from the patient's eye, making sure that the light is directed towards the patient's eye and that you can see the ocular fundus through the ophthalmoscope lens.

Patient Positioning

Before using an ophthalmoscope, it is important to ensure that the patient is positioned correctly for accurate evaluation of their eye. Here are the steps to follow:

1. Comfortable Seating

The patient should be comfortably seated on a chair with a reclining backrest and legs resting on the ground. The head should be turned towards the ophthalmoscope.

2. Adequate lighting

The surrounding environment must be well-lit to allow the operator to clearly see the inside of the patient's eye. If necessary, turn on an additional lamp or move the patient's chair to a brighter area.

3. Glasses removed

If the patient is wearing glasses, they must be removed before evaluating the eye with the ophthalmoscope.

4. Head still

Ask the patient to focus on a bright spot on the opposite wall to keep their head still during eye evaluation.

5. Adequate distance

Maintain an appropriate distance between the ophthalmoscope and the patient's eye to avoid accidental eye injury. The ideal distance is about 15-20 cm.

6. Eye examined

Start the examination with the patient's right eye, then move on to their left eye.

• If using a disposable ophthalmoscope, use a new tip for each eye.
• If using a reusable ophthalmoscope, clean the tip with alcohol before moving on to the other eye.

Remember to explain to the patient what you are doing and address any questions or concerns they may have.

Using the Ophthalmoscope

After preparing the environment and patient, you can use the ophthalmoscope to examine the retina.

Step 1: Adjusting the brightness

Before starting the exam, it's important to adjust the ophthalmoscope's brightness. Generally, it's recommended to start with a low light intensity and gradually increase it until reaching an adequate level. Too much light can cause discomfort for the patient.

Step 2: Choosing the lens

The ophthalmoscope has different lenses that allow you to view the retina at different depths. Generally, you start with a low magnification lens (e.g., 10 diopters) to get an overall view of the patient's eye. If necessary, you can switch to a higher lens to examine specific parts of the retina in detail.

Step 3: Positioning the ophthalmoscope

To position the ophthalmoscope correctly, you need to approach the patient's eye while maintaining a distance of about 15 cm. It's recommended to use your left hand to support the patient's head and keep their eyelids open, while using your right hand to maneuver the ophthalmoscope.

Step 4: Examining the retina

Once the ophthalmoscope is positioned correctly, you can start examining the retina. It's recommended to start from the outer part of the eye and gradually move towards the center. During the exam, it's important to keep a steady hand to avoid sudden movements that may disturb the patient.

• To view the retina, you must look through the ophthalmoscope with one eye while illuminating the patient's eye with light emitted from the other eye of the ophthalmoscope.

• The ophthalmoscope can be moved slightly forward or backward to obtain a better view of the retina.
• In some cases, it may be necessary to ask the patient to look in different directions to examine different parts of the retina.

Step 5: Conclusion of the exam

After completing the examination of the retina, it is important to refocus the patient's eye using an external source of illumination. This way, the patient can resume normal visual activities without any problems. It is also important to clean the ophthalmoscope with a soft cloth and disinfect it before using it again on another patient.

Interpretation of Results

After using the ophthalmoscope, it is important to be able to interpret the results to determine the eye health of the patient. Below are some examples of what to look for and how to interpret what you see.

Normal Eye Fundus

• The optic disc should appear as a round or oval structure with a clear center and a pale pink or orange circumference.
• The retinal arteries appear as thin red lines with a clear center.
• The retinal veins appear as thicker and more tortuous lines than arteries, with a darker color.
• The macula appears as a yellowish area located near the optic disc.

Anomalies of Eye Fundus

• Papilledema: the optic disc appears swollen and blurred, often accompanied by superficial hemorrhages on the retina. This may indicate an increase in intracranial pressure.
• Cotton wool spots: small white or grayish lesions on the retina that can be caused by hypertension or diabetes mellitus.
• Optic neuritis: the optic disc appears inflamed and swollen, often accompanied by a loss of central vision. This can be caused by infections or autoimmune diseases.
• Diabetic retinopathy: the retina presents hemorrhages, microaneurysms, and neovascularization. This is a common sign of uncontrolled diabetes mellitus.

It is important to remember that only a specialized doctor can make an accurate diagnosis based on the results of ophthalmoscopy and other clinical tests.

Conclusion

The use of the ophthalmoscope is an important part of the eye examination and can help identify various eye pathologies. With practice and experience, healthcare providers can become experts in using the ophthalmoscope to provide an accurate and timely diagnosis of eye diseases. However, it is always important to remember that only a specialized doctor can make a definitive diagnosis. So if you suspect you have any eye problems, it is necessary to immediately consult a specialist doctor for a complete evaluation of your eye health.