LATENT SQUINT.pptx (LATENT SQUINT,SQUINT)
- 2. content 1.normal visual axes. 2. binocular vision. 3. squint & its type. 4.definition of latent squint. 5. causes of latent squint. 6. types of latent squint. 7. clinical picture (symptoms & signs) 8. treatment
- 3. normal visual axes. • Optic axis: anatomical axis passing from anterior pole of the eye to the posterior pole. • Visual axis: physiological axis connecting the fovea & the object of regard, passing through the nodal point. • Angle kappa ~ angle alpha : angle between the visual axis & optic axis. Emmetropes: +ve Hypermetropies: large +ve (divergent squint) Myopes: small or even –ve (convergent squint)
- 4. binocular vision. The ability to use the eyes together is called binocular vision. It can be measured and graded by present ing each eye separately but simultaneously with a series of images Steps of binocular vision: • Simultaneous macular perception • Fusion • Stereopsis (depth of focus)
- 5. squint & its type. • Orthophoria: perfect alignment of the eyes, (the 2visual axes are directed towards the object of regard) orthoposition orthophoria fixation target
- 6. • Squint or strabismus refers to ocular misalignment, the two visual axes are not directed (failure to meet) towards the object of regard. • Squint also known as crossed eye or deviation of the eye. squint & its type.
- 7. • squint may be false or true, true squint subdivided to manifest squint (- tropia) and latent squint (- phoria). squint & its type.
- 8. definition of latent squint • Latent squint (hetero - phoria) is a tendency of eye to deviate, but this tendency is controlled subconsciously by the fusional reflexes to maintain binocular single vision.
- 9. causes of latent squint Most common Cause of latent squint: • error of refraction hyperopia cause exophoria due to excess use of accommodation leads to increase convergence (MR more than LR) myopia cause exophoria due to lack of accommodation leads to lack of convergence (MR less than LR) • mild weakness of one or more of extra ocular muscles.
- 10. types of latent squint • Types of latent squint according to tendency of the eye to deviate 1. esophoria (inwards), 2. esophoria (outwards), 3. hyperphoria (upwards) 4. hypophoria (inwards) • according to tendency of eye to roll 1. incyclophoria (inwards) 2. excyclophoria(outwards) • cyclophoria is usually associated with hyper & hypophoria.
- 11. clinical picture (symptoms & signs) Clinical picture of latent squint may be • asymptomatic • symptomatic eye strain Headache intermittent squint intermittent diplopia running of words into one another while reading
- 12. Signs: • corneal light reflex centralized as in normal • cover/uncover (to differentiate) test result the eye deviates under the cover then corrects its position after uncovering, extra ocular muscles motility normal. • Maddox rod test to measure the angle of squint measures the latent deviation for fixation. • Maddox wing test to measure the latent deviation for near fixation and • Titmus fly normal BSV assessment. • worth’s four dots test shows five dots. clinical picture (symptoms & signs)
- 13. treatment •GPs need to appreciate the range of causes of squint, its potential consequences, and hence know when and how urgently a specialist referral is required. •In case of asymptomatic cases no treatment is needed, and if discovered accidentally during examination it is wise not to mention it to the patient. • In case of symptomatic cases the most important treatment is to correct the error of refraction, strengthen the weak muscles by orthoptic training, exercising prism, surgery if other modalities failed to relive prism, base of prism against the deviation.
- 14. prepared by Zeinab Emad younis Abdel-Rahman Faculty of medicine King Salman International university, EGYPT E-mail: zeinabemadwahdan@gmail.com LinkedIn :https://www.linkedin.com/in/zeinab-emad-33380423a/