Primary vs Secondary Angle of Deviation Made Easy | Paralytic Strabismus

Master the core mechanics behind Primary and Secondary Angles of Deviation in paralytic strabismus! 👁️🧠 In this video, we break down why secondary deviation occurs, why secondary deviation is always greater than primary deviation (Secondary is greater than Primary), and how Hering's Law of Equal Innervation governs eye muscle alignment during fixation. Whether you are an optometry student, ophthalmology resident, orthoptist, or eye care professional reviewing strabismus and motility examination concepts for exams or clinical practice, this guide makes complex neuro-ophthalmology simple and actionable. 📌 What You’ll Learn in This Video: • Definition of Primary Deviation (fixation with the normal eye) • Definition of Secondary Deviation (fixation with the paretic/affected eye) • Physiological mechanism explaining why Secondary Deviation is greater than Primary Deviation • Role of Hering's Law of Equal Innervation and over-innervation to yoke muscles • Clinical examples and case walk-throughs using Lateral Rectus & Medial Rectus palsy ⏱️ TIMESTAMPS / CHAPTERS: 00:00 - Introduction to Primary & Secondary Deviation 00:58 - What is Primary Deviation? (Fixation with Normal Eye) 02:00 - What is Secondary Deviation? (Fixation with Affected Eye) 03:08 - Key Clinical Finding: Secondary vs Primary Angle 03:30 - Underlying Mechanism & Muscle Innervation 04:58 - Hering's Law of Equal Innervation Explained 06:40 - Clinical Example: Lateral Rectus Palsy Walkthrough 07:32 - Final Summary & Key Takeaways 🔔 Subscribe to OPTOMETRY WITH TARIK for more clinical skills guides, binocular vision lectures, and optometry exam prep tutorials! 💬 Got questions about Hering's Law or paralytic squint? Drop your questions in the comments below—I reply to every comment! 👍 If you found this video helpful, please LIKE, SHARE, and SUBSCRIBE to support the channel! #Optometry #Strabismus #HeringsLaw #PrimaryDeviation #SecondaryDeviation #EyeExam #OptometryStudent #Ophthalmology #BinocularVision #ParalyticSquint #OptometryWithTarik