Search results
Results from the WOW.Com Content Network
Digital Compound Monocular Microscope. If you have more to spend, this digital compound microscope is excellent. It features a 0.3-megapixel camera to capture and display images on a computer ...
Accommodating to a distance nearer than 6 meters makes the ciliary muscles work harder than they need to, leading to fatigue. [5] Some binocular microscopes are designed so that the vergence of the eyes is correct for a 6-meter viewing distance. Accommodating to a closer distance will tend to converge the eyes, leading to double vision.
used to search for magnified examination of the anterior segment of the eye (uniocular or binocular) Jackson's cross cylinder: used to check the power and axis of a cylindrical lens: Maddox rod: used to test for latent squint and retinal function Refraction box: has lenses of different powers for refraction testing: Slit lamp bio microscope
The binocular device is a generally compact instrument for both eyes designed for mobile use. A camera could be considered a type of optical instrument, with the pinhole camera and camera obscura being very simple examples of such devices.
Most roof prism binoculars use either the Schmidt–Pechan prism (invented in 1899) or the Abbe–Koenig prism (named after Ernst Karl Abbe and Albert König and patented by Carl Zeiss in 1905) designs to erect the image and fold the optical path. They have objective lenses that are approximately in a line with the eyepieces.
For example, a 10 × 42 binocular has a 4.2 mm wide exit cone, and fairly comfortable for general use, whereas doubling the magnification with a zoom feature to 20 × results in a much more critical 2.1 mm exit cone. Optics showing eye relief and exit pupil 1 Real image 2 Field diaphragm 3 Eye relief 4 Exit pupil
An example of the Landolt C eye chart (also known as the Japanese eye chart.). Numerous types of eye charts exist and are used in various situations. For example, the Snellen chart is designed for use at 6 meters or 20 feet, and is thus appropriate for testing distance vision, while the ETDRS chart is designed for use at 4 meters. [16]
One of the most important properties of microscope objectives is their magnification.The magnification typically ranges from 4× to 100×. It is combined with the magnification of the eyepiece to determine the overall magnification of the microscope; a 4× objective with a 10× eyepiece produces an image that is 40 times the size of the object.