Secondary detion is more than primary detion is a feature of
Broadly, strabismus can be classified as below:I. Apparent squint or pseudostrabismus.II. Latent squint (Heterophoria)III. Manifest squint (Heterotropia)1. Concomitant squint2. Incomitant squint INCOMITANT SQUINTIt is a type of heterotropia (manifest squint) in which the amount of detion varies in different directions of gaze. It includes following conditions:1. Paralytic squint,2. 'A' and 'V' pattern heterotropias,3. Restrictive squint PARALYTIC STRABISMUSIt refers to ocular detion resulting from complete or incomplete paralysis of one or more extraocular muscles Primary detion. It is detion of the affected eye and is away from the action of the paralyzed muscle, e.g., if lateral rectus is paralyzed the eyeis converged.2. Secondary detion. It is a detion from the normal eye seen undercover when the patient is made to fix with the squinting eye. It is greater than the primary detion. This is due to the fact that the strong impulse of innervation required to enable the eye with the paralyzed muscle to fix is also transmitted to the yoke muscle of the sound eye resulting in a greater amount of detion. This is yoke muscles. In Paralytic squint, the secondary detion is more than the primary detion. Reference: Khurana Ophthalmology; 4th edition; Strabismus and Nystagmus
Accommodative squint
Paralytic squint
Infantile esotropia
Alternate exotropia
Anatomy, Development and clinical examination