Ophthalmic Ultrasound is an essential test done in management of Ocular Trauma, patients with poor view of fundus (posterior segment of eye) due to poor clarity of ocular media
Eleven months after discharge, the patient's best-corrected visual acuity was 20/25, and his ocular media
were clear and without any lesions.
Clinically, any opacity of the ocular media
reduces the brightness of test stimuli and background equally, and therefore has no effect other than overall depression of retinal sensitivity; this is reflected in changes to the total deviation plot and global indices, (20) but no significant changes to the pattern deviation plot as this filters out the depression to identify focal losses (unless concurrent disease such as glaucoma is present) (Figure 1).
For short pulse lasers, typical in lasers used in fire-control devices (laser rangefinders and designators), the beam is transmitted through the outer ocular media
(cornea, aqueous humor, lens, vitreous humor) to a small spot on the retina, resulting in a localized, intense temperature elevation or even a plasma formation that can disrupt membranes and produce a small hemorrahage.
They further stated that since TTT utilizes near-infrared light to deliver hyperthermia to the posterior pole, there is minimal absorption by clear ocular media
It is not an absorption effect brought about by the ocular media and until recently it was only thought to be shown by foveal and peripheral cones.
The Stiles-Crawford Effect may well be of greatest importance to the visual process by suppressing the effect of stray light within the ocular media.
Some of these mechanisms involve selective absorption in the ocular media
, for example the lens and macular pigments, whilst the depth of field/pupil size of the eye also reduce the visual effects from peripheral aberrations, thus minimising effects on visual acuity (VA).
Any infrared rays that are transmitted through the ocular media
to the retina are absorbed by the pigment epithelium of the retina.