Ads
related to: blind eye contacts no pupil limit price definition
Search results
Results From The WOW.Com Content Network
When the pupil is small (1–2 mm), image sharpness may be limited by diffraction of light by the pupil (see diffraction limit). Between these extremes is the pupil diameter that is generally best for visual acuity in normal, healthy eyes; this tends to be around 3 or 4 mm. If the optics of the eye were otherwise perfect, theoretically, acuity ...
A contact lens rests directly on the surface of the cornea and moves in sync with all eye movements; consequently, a contact lens is always almost perfectly aligned on center with the pupil, and there is never any significant off-axis misalignment between the pupil and the optical center of the lens.
Distribution of rods and cones along a line passing through the fovea and the blind spot of a human eye [1]. A blind spot, scotoma, is an obscuration of the visual field.A particular blind spot known as the physiological blind spot, "blind point", or punctum caecum in medical literature, is the place in the visual field that corresponds to the lack of light-detecting photoreceptor cells on the ...
No abnormality detected (is frequently used but is not recommended) NCT: Non-contact tonometer ND: Neutral density filter NLP: No light perception No light perception is considered total visual impairment, or total blindness; see Visual impairment#Classification: NPC: Near point of convergence or no previous correction NRC Normal retinal ...
Legally blind indicates that a person has less than 20/200 vision in the better eye after best correction (contact lenses or glasses), or a field of vision of less than 20 degrees in the better eye. Totally blind students learn via braille or other non-visual media.
PL is an abbreviation for plano or plain, meaning no prescription; PD or IPD Pupillary Distance or Interpupillary Distance, respectively. It is the distance between pupil centers. BVD Back vertex distance is the distance between the back of the spectacle lens and the front of the cornea (the front surface of the eye). This is significant in ...