Indirect ophthalmoscopes are essential tools for eye examinations, combining a light source and an imaging system. These instruments use visible or infrared light to illuminate the eye’s fundus, capturing detailed images of its structure. By magnifying these images, doctors can better diagnose and monitor eye conditions.
Unlike direct ophthalmoscopes, indirect versions use a front lens held in front of the patient’s eye. The light reflected from the eye’s fundus passes through this front lens, forming an enlarged, inverted real image that is then processed by the imaging system.
The Role of Aspherical Lenses
The use of spherical lenses in these devices often leads to suboptimal imaging. Therefore, aspherical lenses are preferred due to their ability to correct aberrations more effectively. High-order aspherical lenses, in particular, have multiple adjustable parameters to finely tune the lens curvature, significantly enhancing image sharpness and reducing distortion.
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