Handwriting with a preferred retinal locus for AMD with scotomas

Area of Science:

• Ophthalmology
• Neuroscience
• Human Factors

Background:

• Age-related macular degeneration (AMD) is a leading cause of vision loss.
• Macular scotomas, common in AMD, significantly impact visual function.
• Legible handwriting is often compromised in individuals with macular scotomas.

Purpose of the Study:

• To investigate the causes of poor handwriting in AMD patients with macular scotomas.
• To document the retinal location of the pen tip relative to the scotoma and fixational preferred retinal locus (fPRL).

Main Methods:

• Participants with AMD-induced macular scotomas and age-matched controls wrote in a scanning laser ophthalmoscope.
• Retinal positions of scotoma, fixation area (fPRL/fovea), and pen tip were analyzed.
• Handwriting performance was assessed by text angle and placement within guides.

Main Results:

• Both controls and scotoma subjects used their fovea or fPRL to guide the pen tip.
• Scotoma subjects' writing sloped downward more steeply than controls'.
• Poor handwriting correlated with fPRL eccentricity, reduced visual acuity, and scotoma obscuration of writing guides.

Conclusions:

• The fixational preferred retinal locus (fPRL) is used for handwriting, not a separate 'handwriting PRL'.
• Difficulty placing letters accurately, due to reduced fPRL visual acuity and scotoma obscuration, causes poor handwriting in AMD.
• The fPRL and fovea actively monitor the pen tip during writing.