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Scanning laser ophthalmoscopy developed as a method to view a distinct layer of the living eye at the microscopic level. The use of confocal methods to diminish extra light by focusing detected light through a small pinhole made possible the imaging of individual layers of the retina with greater distinction than ever before. [4]
Light entering the eye strikes three different photoreceptors in the retina: the familiar rods and cones used in image forming and the more newly discovered photosensitive ganglion cells. The ganglion cells give information about ambient light levels, and react sluggishly compared to the rods and cones.
The pupil of the eye dilates in the dark to enhance night vision. Shown here is a pupil of an adult naturally dilated to 9 mm in diameter in mesopic light levels. The average human eye is not able to dilate to this extent without the use of mydriatics. Nocturnal mammals have rods with unique properties that make enhanced night vision possible ...
The various cone cells are maximally sensitive to either short wavelengths (blue light), medium wavelengths (green light), or long wavelengths (red light). Rod photoreceptors only contain one type of photopigment, rhodopsin, which has a peak sensitivity at a wavelength of approximately 500 nanometers which corresponds to blue-green light. [ 6 ]
A Marcus Gunn pupil indicates an afferent defect, usually at the level of the retina or optic nerve. Moving a bright light from the unaffected eye to the affected eye would cause both eyes to dilate, because the ability to perceive the bright light is diminished. Specialty: Ophthalmology, Optometry
Red-eye effect on dark brown eyes. The same holds for animals. The color of the iris itself is of virtually no importance for the red-eye effect. This is obvious because the red-eye effect is most apparent when photographing dark-adapted subjects, hence with fully dilated pupils. Photographs taken with infrared light through night vision ...
n November 1954, 29-year-old Sammy Davis Jr. was driving to Hollywood when a car crash left his eye mangled beyond repair. Doubting his potential as a one-eyed entertainer, the burgeoning performer sought a solution at the same venerable institution where other misfortunate starlets had gone to fill their vacant sockets: Mager & Gougelman, a family-owned business in New York City that has ...
Normally, as part of the pupillary light reflex, the pupil dilates in the dark and constricts in the light to respectively improve vividity at night and to protect the retina from sunlight damage during the day. A mydriatic pupil will remain excessively large even in a bright environment. The excitation of the radial fibres of the iris which ...