From the Guidelines
Drusen are generally not disqualifying for aviation duties, but they require careful monitoring due to their potential to progress to more serious eye conditions, such as age-related macular degeneration (AMD), which can compromise visual function and impact flight safety. Pilots with drusen should undergo regular comprehensive eye examinations, typically every 6-12 months, with an ophthalmologist experienced in aeromedical assessments, as recommended by the American Academy of Ophthalmology 1. These examinations should include:
- Visual acuity testing
- Visual field assessment
- Retinal imaging to monitor for any changes If drusen are small, hard, and few in number without affecting central vision or visual fields, most aviation authorities will permit continued flying duties. However, soft, large, or numerous drusen, especially those associated with AMD, may lead to flying restrictions or disqualification if they compromise visual function, as noted in the comprehensive adult medical eye evaluation preferred practice pattern guidelines 1. Pilots should report any changes in vision immediately, including distortion, blurring, or scotomas. No specific medication is required for drusen themselves, but antioxidant vitamins, such as the AREDS2 supplement formulation, may be recommended in some cases to slow the progression of AMD, as shown in the Age-Related Eye Disease Study (AREDS) 1. The aeromedical concern with drusen stems from their potential to interfere with critical visual tasks during flight operations, particularly if they progress to cause central vision loss or visual field defects that could impact instrument reading, traffic detection, or runway alignment during critical phases of flight. Air travel itself does not pose a significant risk to individuals with drusen, but it can exacerbate existing eye conditions, such as dryness and discomfort, due to the low humidity inside airplanes, as noted in the study on eye disease and international travel 1.
From the Research
Drusen in Aeromedical Considerations
- Drusen are extracellular deposits of debris that accumulate on Bruch's membrane, and their presence is a risk factor for visual deterioration in age-related macular degeneration (AMD) 2.
- The formation of drusen is associated with a degeneration of the retinal pigment epithelial (RPE) cells and photoreceptors in the retinal centre (macula), and can lead to visual impairment 2, 3.
- Drusen can be classified into different types, including hard and soft drusen, cuticular drusen, reticular pseudodrusen, and "ghost drusen", each with distinct characteristics and associations with AMD 4.
- The presence of drusen has been linked to local and distant disruptions to human retinal pigment epithelium cells, including changes in cell morphology and distribution 5.
- Drusen ooze, a phenomenon characterized by hyperreflective dots overlying a collapsing drusen or pseudodrusen, has been identified as a predictor for progression of dry age-related macular degeneration 6.
Aeromedical Implications
- The presence of drusen and their associated visual impairment may have significant implications for aeromedical considerations, particularly in individuals with AMD 2, 3.
- The classification and characterization of drusen, as well as the identification of drusen ooze, may be important factors in assessing an individual's visual fitness for flight 4, 6.
- Further research is needed to fully understand the relationship between drusen and visual deterioration, as well as the aeromedical implications of drusen in AMD 2, 3, 4, 5, 6.