Persistence of vision

The relation between the discontinuous procedure of Eqs. (6-124) and the continuous idealization of Eq. (6-126) is the same as that which exists between the sequence of discrete stroboscopic points and the pseudocontinuous motion of the point of the wheel which appears to the eye owing to the persistence of vision. 

POV-ray is available from the Persistence of Vision Ltd. (2004), Persistence of Vision Raytracer (Version 3.6) computer software website, http //www.povray. org. 

Poulsen, C., and Poedenphant, L. (2000). Unpublished. GenhankAccession No. AW428839. POV-Team (1997). Persistence of Vision Ray Tracer POV-Team. Available at http //... 

Motion pictures, also called film, cinema or movies, are a series of images, recorded on strips of film, that create the illusion of continuous motion. A series of rapidly shown images appear to move because of a phenomena called ihe, persistence of vision. The eye does not react instantly to changes in its field of vision. In fact, the eye continues to see an image for 1/10- 1/20 of a second after it changes. So if a sequence of images can be shown at a rate of approximately 20 per second, it will appear as continuous motion to the eye. That is Just what happens in a motion picture. 

Persistence of vision— A phenomena of the eye, which continues to register an image for a short time after it disappears. This makes motion pictures possible. 

The brain is tricked into seeing a rapid sequential series of still images as motion by the physiological process called persistence of vision. 

As an inhibitor of plasma (pseudo) cholinesterase, DFP produced only minimal reversal of scopolamine-induced incapacitation. Note the very low plasma ChE levels, with only minor decreases in RBC ChE (Fig. 71). DFP does improve near vision when applied to the eye (David Flarper, unpublished data) suggesting that paralysis of the muscles of visual accommodation is probably peripheral in origin. Persistence of pupillary enlargement (in the face of systemic treatment with physostigmine) may be due to physiological or pK factors, causing limited access to the iris. 

In humans, severe eye irritation occurs at 2 5 ppm and irritation of the nose is moderate at 12.5ppm. In workers exposed to a moderate vapor level there was a syndrome of lacrimation, retrobulbar pain, photophobia, and blurring of vision. The symptoms persisted for up to 48 hours. Skin contact with the liquid has a delayed effect, causing aching that begins several hours after contact, followed by the formation of vesicles. Splashes of the liquid in human eyes have caused moderately severe reactions. ... 

Adverse reactions include the following Hives rashes angioedema nausea, dyspepsia (5% to 25%) heartburn epigastric discomfort anorexia massive Gl bleeding occult blood loss potentiation of peptic ulcer persistent iron deficiency anemia prolongation of bleeding time leukopenia thrombocytopenia purpura decreased plasma iron concentration shortened erythrocyte survival time fever thirst dimness of vision. 

An unusual condition that has been tentatively ascribed to clomiphene is persistence of the hyperplastic primary vitreous, that is fetal ophthalmic tissue that normally resolves before birth. If more than a trace of the material persists, ocular complications, including cataract and retinal detachment, can result. In a case reported from Canada, there had been an estimated 3 weeks of exposure to high doses of clomiphene (100 mg/day) after gestation, and the child s vision was severely impaired (20). This is probably not a mere chance association, since several cases of visual defects of various types after exposure to clomiphene have been described before, and in some animal studies the drug does adversely affect ocular development. 

In diffuse anterior scleritis (Figure 28-4), the pain is often less severe. This form of scleritis is the mildest and most common type, and it manifests as an area of sectorial or diffuse dilation of the deep episcleral vascular plexus with overlying and adjacent episcleritis that can affect the whole eye. There can be mild anomalous changes in the blood vessels that may persist even after successful treatment, which is associated with a 9% incidence of vision loss. 

A 76-year-old non-smoking woman with giant-cell arteritis who had a normal chest X-ray was taking prednisone 45 mg/day and ticlopidine 250 mg bd for persistence of cloudy vision. After 1 month of ticlopidine therapy, she developed increasing dyspnea and a pruritic rash. Chest radiography showed diffuse interstitial... 

The ointment persists longer on the corneal surface and needs to be applied only twice daily, but can cause stickiness and blurring of vision. Drops are used four times daily. Treatment should be continued for 24 hours after symptoms have cleared. If symptoms do not significantly improve within 48 hours, treatment should be discontinued and the patient referred for medical advice. 

---