Direct image-creating aspheric lens for indirect ophthalmoscopy

Area of Science:

• Ophthalmology
• Optical Engineering
• Medical Devices

Background:

• Indirect ophthalmoscopy is crucial for visualizing the fundus.
• Conventional indirect ophthalmoscopy lenses produce inverted images, requiring mental reorientation.
• A need exists for improved optical systems that simplify fundus visualization.

Purpose of the Study:

• To describe a novel compact handheld optical lens.
• To achieve a real, upright image of the fundus during indirect ophthalmoscopy.
• To enhance the usability of indirect ophthalmoscopy.

Main Methods:

• A compound lens system comprising three double aspheric lenses was designed.
• The lenses are mounted coaxially within a plastic housing.
• Specific lens separations (30.96 mm and 19.38 mm) and an optical system length of 79.63 mm were utilized.

Main Results:

• The lens design successfully generates an upright aerial image of the fundus.
• This image is located between the lens and the observer.
• The upright image contrasts with the inverted image from conventional indirect lenses.

Conclusions:

• The developed aspheric lens directly creates an upright fundus image.
• This facilitates binocular indirect ophthalmoscopy.
• Eliminates the cognitive burden of mentally reorienting inverted images, improving diagnostic efficiency.