Retinal shadows of multisegment lenses in fundus imaging

Area of Science:

• Ophthalmic optics
• Retinal imaging technology

Background:

• Scanning laser ophthalmoscopy (SLO) can reveal retinal shadows when patients wear multisegment or diffusion optic spectacle lenses.
• The precise optical mechanisms causing these shadows require further elucidation.

Purpose of the Study:

• To offer a detailed optical explanation for retinal shadows observed in scanning laser ophthalmoscopic images.
• To investigate the influence of spectacle lens design on these observed phenomena.

Main Methods:

• Utilized a scanning broad line fundus imaging system with participants wearing a multisegment spectacle lens.
• Performed ray-tracing and image simulations using a Maxwellian illumination model and varying light source sizes.
• Simulated light refraction through spectacle lenses and eye models to predict retinal irradiation distribution.

Main Results:

• Retinal shadow patterns were visible on the live infra-red preview but not in the final recorded retinal images.
• Simulations indicated that the size of the light source significantly impacts the visibility of predicted retinal shadows.
• Increasing light source diameter led to progressively less discernible circular shadows corresponding to lenslet positions.

Conclusions:

• Provided a sophisticated optical explanation for retinal shadows associated with multisegment spectacle lenses.
• These shadows are dependent on specific illumination conditions and may not always be apparent in recorded images.