What is the procedure for performing direct fundoscopy?

Direct Fundoscopy Procedure

Direct fundoscopy should be performed using a systematic approach that includes proper patient positioning, appropriate instrument handling, and a methodical examination technique to optimize visualization of the fundus.

Preparation

• Before beginning the examination, ensure the room is darkened to maximize pupillary dilation and improve visualization of the fundus 1
• Consider using mydriatic drops such as tropicamide for pupillary dilation when a more comprehensive examination is required 2
• Position the patient comfortably, either sitting or lying down, with their head stabilized 1
• Explain the procedure to the patient to ensure cooperation during the examination 1

Equipment

• Use a direct ophthalmoscope with appropriate light source 1
• Ensure the ophthalmoscope battery is charged and functioning properly 1
• Alternative technologies such as smartphone-based fundoscopy with a 20D lens may be considered as they have been shown to be easier to use for beginners 3, 4

Technique

1. Initial approach:

   • Set the ophthalmoscope lens power to "0" initially 1
   • Hold the ophthalmoscope in your right hand to examine the patient's right eye (and vice versa) 1
   • Position yourself approximately 30 cm from the patient at a 15-degree angle to their line of sight 1

2. Approaching the eye:

   • Direct the light beam toward the pupil, observing the red reflex 1
   • Gradually move closer to the patient (approximately 5 cm from their eye) while maintaining the red reflex 1
   • Use your free hand to gently hold the patient's upper eyelid if needed 1

3. Focusing:

   • Adjust the lens power dial to bring the fundus structures into focus 5
   • For emmetropic eyes, maintain the "0" setting; for myopic patients, rotate to negative numbers; for hyperopic patients, rotate to positive numbers 5
   • The standard magnification for an emmetropic eye is approximately 15× 5

4. Systematic examination:

   • Begin by locating and examining the optic disc, noting its color, margins, and cup-to-disc ratio 1
   • Follow blood vessels outward from the disc in all four quadrants (superior, inferior, nasal, temporal) 1
   • Pay special attention to the macula (located approximately 2 disc diameters temporal to the optic disc) 1
   • Examine the peripheral retina by having the patient look in different directions 1

Special Considerations

• For patients with narrow anterior chamber angles, be cautious with pupillary dilation as it may precipitate acute angle-closure crisis 1
• In patients with suspected narrow angles, perform gonioscopy before dilation or use alternative methods to visualize the fundus 1
• For patients with corneal edema, topical glycerin may be used to temporarily clear the cornea for better visualization 1
• If a comprehensive examination is not possible through an undilated pupil, consider using alternative imaging methods such as OCT or non-mydriatic fundus photography 1

Common Pitfalls and Solutions

• Poor visualization: If the view is obscured, check for proper alignment of the light beam with the pupil 1
• Patient discomfort: Minimize examination time and use the lowest comfortable light intensity 1
• Difficulty locating the optic disc: Have the patient fixate on a distant target, then follow the vessels centrally 1
• Corneal reflections: Adjust your angle slightly to eliminate reflections 1
• Limited field of view: Remember that direct ophthalmoscopy provides only a 10-15° field of view; methodically examine all areas by having the patient look in different directions 5

Alternative Approaches

• For patients who cannot cooperate or when better documentation is needed, consider using smartphone fundoscopy which has been shown to be more user-friendly for beginners 3, 4
• Non-mydriatic fundus cameras may be used when available, especially for screening purposes 1, 3
• For comprehensive examination, indirect ophthalmoscopy or slit-lamp biomicroscopy with appropriate lenses provides a wider field of view 1

Direct fundoscopy remains a valuable clinical skill for general practitioners and specialists alike, allowing for the detection of important ocular and systemic conditions such as diabetic retinopathy, hypertensive changes, and papilledema 6, 4.