Pupillary Pathway Lecture PDF

PRDO130 - PHYSIOLOGICAL OPTICS 2 2nd Year 2nd Sem | LECTURE Systems in the Body Nervous System ​ it’s a group of function in the human body ​...

PRDO130 - PHYSIOLOGICAL OPTICS 2 2nd Year 2nd Sem | LECTURE Systems in the Body Nervous System ​ it’s a group of function in the human body ​ Central control center of the human body Integumentary ​ refers to skin as the ​ Composed of the central nervous system (CNS) and System primary or principal peripheral nervous system (PNS) organ ​ Basic unit is neuron Digestive System ​ refers to food digestion ​ Even if you receive so much stimulation or signal but and absorption of food, if the brain cannot process it and direct to whatever vitamins and nutrients organ in the body, you will not be able to react. on food ​ starts from the mouth to excretory portion Is the Nervous System the most important of all the systems? Vascular System or ​ Cardiovascular includes ​ Yes, because it is the central control of the body. It Cardiovascular the heart as the organ ad controls our responses, thoughts, memories, System Vascular refers to blood feelings, how we understand, reaction, even the vessels involuntary reactions of the body are controlled by the brain Reproductive System ​ Male and female sex ​ Feelings are caused by chemical reactions in the organs brain ​ Pheromones are involved when someone is attracted to another person and it starts in the Pupil brain. From the sense of smell (the stimulant or ​ Is it part of the CNS? No, because it just an opening change in environment) and when you smell ​ The size of the pupil is controlled by the Nervous someone and processed it in the brain that’s the System particularly the central and peripheral NS start of whatever feeling you have to another because it sends innervation particularly person parasympathetic innervation for constriction and sympathetic innervation for dilation Central Nervous System ​ The opening is controlled by muscles found in the eyes ​ Consists of the brain and spinal cord ○​ sphincter: circular ​ Pupillary pathway ○​ dilator: radial ​ Center of dilation: from the CNS the signal is cascaded down to the PNS ​ It may constrict when the sphincter pupillae muscles contract and the radial muscle relax Peripheral Nervous System ​ It may dilate when the radial muscles contract and ​ Consists of the branches of central nervous system circular muscle will relax ​ Controls the afferent and efferent nerves ​ Contains somatic and autonomic (voluntary and ​ Normal size of the pupil: 2 - 8mm involuntary nerves) nerves ○​ Involuntary nerves includes pupillary light reflex Stimulus to Constriction Stimulus to Dilation  PRDO130 - PHYSIOLOGICAL OPTICS 2 2nd Year 2nd Sem | LECTURE ​ Parasympathetic ​ Sympathetic pathway pathway Swing Flashlight Test ​ Near fixation ​ Looking at far ​ determine the direct and indirect response ​ Bright illumination ​ Dim or reduced illumination PERRLA ​ In case of ​ Pain ​ to know if the pupils constrict with light stimulus accommodation: ​ Strong emotions see clearly at near ​ Cognitive or ​ Accommodation or when you look mental activity ○​ instruct patient to look at near clearly at near ​ Lack of sleep ○​ if the pupil constrict, it has response to there is accommodation constriction brought by about ​ Test to gauge the strength of constriction by convergence ○​ fastness or speed of reaction of the pupils ○​ If you want to check its reaction, observe the pupils and introduce the stimulus Do young and old people have the same size of pupil in bright illumination? Brisk PERRLA⁺⁴ ​ No, because it decreases in size. Fast PERRLA⁺³ ​ For every decade, the pupils constrict by 0.3mm Moderate PERRLA⁺² ​ They attribute these due to stiffening of the iris or Slow or you can barely see PERRLA⁺¹ muscles. Similar to crystalline lens, the elasticity is it reduced No reaction to light or 0 accommodation Inter Pupillary Distance ​ It is the distance between the two centers of the 4 Types of Reflexes pupil which is equivalent to the distance between the two center of rotation of the eye 1.​ Pupillary Light Reflex ​ Observe eye with no stimulus: Consensual PERRLA ​ Constriction with no stimulus on that eye but there is ​ Pupils Equally Round and Reactive to Light and on the other eye or observing the non-stimulated Accommodation eye: Consensual or Indirect ​ Test to identify the integrity of the pupil ​ Observe eye with light stimulus - Direct ​ During external examination, pupil are equally round ​ Constriction with stimulus - Direct or circular in shape ​ You must observe response of both eyes on both ​ To determine whether pupils are reactive to light, occasion (direct and indirect) you use pen light and shine it on the right and left ○​ similar to swing flashlight test but not the 2.​ Pupillary Dark Reflex same ​ Removing light stimulus  PRDO130 - PHYSIOLOGICAL OPTICS 2 2nd Year 2nd Sem | LECTURE ○​ expect dilation ​ Disconnect all of these three will result to either eye ` strain, headache, phorias in the patient, or binocular ​ Introduce light on both eye and eyes are separated vision problems with the septum to make sure that there will be no light passing through towards the other eye ​ Theoretically, we should be seeing two images but ​ Use two light stimulus to both eyes because you are because of the concept of single binocular vision going to observe dilation with removal of light these images seen by the two eyes are merged into stimulus one. The fusion of images are more important when the patient fixates at near ​ Point of Observation: starting from right direct, left direct, left indirect, right indirect Pupillary Pathway 3.​ Pupillary Near Response or Reflex ​ Constriction: innervated by parasympathetic nerves ​ Dilation: innervated by sympathetic nerves ​ Stimulus: near fixation ​ Patient is looking at far while you are observing both Afferent Pathway for Parasympathetic Pathway eyes, ask the patient to look at the tip of the ballpen ○​ If there is constriction, there is a positive ​ Ganglion Cell reaction to near stimulus ​ Retina ​ Optic Nerve ​ Optic Chiasm 4.​ CilioSpinal Reflex ​ Optic Tract ​ Pretectal Nucleus ​ Pupils will dilate in response to stress ​ In time of stress or anxiety there is an increase in blood sugar level, increase in blood pressure, Efferent Pathway for Parasympathetic Pathway increase in oxygen, endorphins and oxytocin inside the brain ​ Edinger–Westphal Nucleus: Center of constriction ​ Oculomotor Nerve ​ Ciliary Ganglion Three Synkinetic Action ​ Short Ciliary Nerve goes hand in hand ​ Sphincter Pupillae Constriction Afferent Pathway for Sympathetic Pathway Accommodation ​ Look at far and near to see clearly ​ Ganglion Cell ​ Retina ​ Objective: clear vision ​ Optic Nerve ​ Optic Chiasm ​ Optic Tract ​ Locus Coeruleus Convergence ​ Inward turning of the eye or move focus from distance to near Efferent Pathway for Sympathetic Pathway ​ Objective: single binocular ​ CilioSpinal Center of Budge: found between C8 to vision T2 ​ Cervical Ganglion ​ Trigeminal Nerve (Ophthalmic division) ​ Long Ciliary Nerve  PRDO130 - PHYSIOLOGICAL OPTICS 2 2nd Year 2nd Sem | LECTURE ​ Dilator Pupillae