Case Study: Pin Point Pupil

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Pin point pupil
What is the pupil?
The pupil is a rounded medium sized hole which allows light into the eye that hits the retina (located at the back of the eye). It is located at the center of the iris as shown below.

Fig. 1 Parts of the eye

Normal working of the pupil
The pupil being the entry point of light, it has to regulate the amount of light that enters the eye. In bright light, the pupil usually constricts (becomes smaller) so as to reduce the amount of light reaching the retina. For a person who is in a dark room or a room with dim lighting, the pupil dilates (becomes bigger) in order to allow as much light as possible to enhance clear vision. Fig. 2 Eye in bright light (left) and eye in dim light (right)

What is pinpoint …show more content…

However, if the constriction goes below 2.0 mm in normal lighting (pinpoint size) then there is a problem caused by a disorder known as pinpoint or miosis (also myosis). The condition is usually associated with the slow reaction of the ganglion cells compared to the cone and rod cells which are all photoreceptors. Pinpoint pupils are important indicators for diagnostics and prognostics during emergencies.

Fig. 3 Patient with pinpoint pupil

Pupillary observation
When you visit a doctor for any diagnosis emphasis is put on observing the eye as it always gives telltale signs of underlying issues. In pupillary observation, the focus is on the size and shape of the pupils in bright light. The normal size of the pupil ranges from 2-8 mm and are equal in size. Both pupils should also react equally when examined.
The consultant then reduces the light and instructs the patient to stare at a far object say the wall. Here asymmetry is sort using an opthalmoscope. If an abnormality is present then the pupils will vary in the red reflex of theinstrument.

Fig. 4 Pupillary examination

Reflexes tested during pupillary …show more content…

They are usually used as pain relievers but unregulated use can cause addiction. Abusers prefer it since it modifies consciousness and awareness. Overdose of opioids such as oxycodone and morphine,lead to pupil constriction.
Benzodiazepines- These are also known as benzos and are also psychoactives. Other problems associated with them include: panic attacks, seizures, anxiety and insomnia.
Infections
Both viral and bacterial infections could lead to the pupil becoming pinpoint size. An infection of the eye such as uvetiscauses harm to the centre of the eye which can become inflamed causing adhesions of the iris and the lens. The eye tissues clump together restricting expansion and contraction of the pupil.
Other infections may not be directly on the eye but can directly affect the pupil size. Neurosyphilis is one such disease that affects the spinal cord or the brain to the point of affecting sensory organs of the eye.
Problems of the brain
Brain complications such as pontine infarction and hemorrhaging lead to injuries of the brain causing stroke, illness and brain damage. When the front part of the brain is affected both pupils become small but when other areas of the brain are affected one pupil dilates as the other

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