Binoclar balancing by kausar ali
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The final step of subjective refraction is binocular balancing, which equalizes the accommodative effort between the two eyes. This allows for both retinal images to come into focus simultaneously. An imbalanced correction can cause asthenopia due to unstable accommodation. Several binocular balancing tests are commonly used, including fogging and prism dissociation. Fogging involves alternately placing -0.25D spheres before each eye while the patient identifies the clearer image at 6/30 or 6/20. Prism dissociation uses vertical prisms and fogging to have the patient view two separate lines, identifying the more blurred image to establish balancing between the eyes.
Binoclar balancing by kausar ali
- 2. Binocular Balancing By Kausar Ali 4th semester Student Pef University Doctor of optometry
- 3. Binocular balancing : Definition : The final step in the subjective refraction is called ‘Binocular balancing ʼ. Binocular balancing is the is Equalizing the accommodative effort ʼ ʻ spherical equalization ʼ Aims : This allow both eyes have the retinal image simultaneously in focus.
- 4. An imbalanced correction often leads to asthenopia because of unstable accommodation . Binocular balancing test is not balance the VA but to balance the state of accommodation of the two eyes. The test not only test best sphere but also be used for checking astigmatic compound under binocular viewing condition. Alternative to binocular balancing tests :
- 5. 1) cycloplegic Refraction. 2) Binocular Refraction.
- 6. Criteria: These techniques are not the method of choice when amblyopia is present in one eye . Deep suppression should not be present . There should be BCVA and essentially almost the same VA in both eyes .
- 7. Binocular Balancing o The final important step of subjective refraction is to make certain that accommodation has been relaxed equally in two eyes . oSeveral methods of binocular balance commonly used . oMost require that the correct visual acuity be nearly in two eyes . oFogging and prism dissociation .
- 8. Fogging: oWhen the end point refraction is fogged using +2.0 sphere before each eye. oThe visual acuity should be reduced to (6/60 – 6/30) . oPlace a -0.25 D sphere first before one eye and then the other and rapidly alternate cover , oThe patient should then be able to identify the eye with the -0.25 sphere before it has having the clearer image at 6/30 or 6/20 level.
- 9. oIf the eyes are not balance, sphere should be added or subtracted n 0.25 step until balance is achieved . oThe fogging method also provides information regarding appropriate sphere power . oEither the eye over minused or under plussed the patient reads further down the chart as far as 6/20 , 6/15 or even 6/15 with the +2.0 fogging spheres in place . oIn the above case , the refraction end point should be reconsider .
- 10. Prism dissociation: oThe most sensitive test of binocular balancing is prism dissociation . oFor this test the refraction end point is are fogged with +1.00 sphere and vertical prism of 4 or 5 prism diopters are placed before one eye . oThis cause the patient to see 2charts ,one above the other . oA single line , usually (6/12) is isolated on the chart .
- 11. oThe patient seeing 2 separate lines simultaneously, one for each eye. oDifference between the fogged image in the two eyes of as little as 0.25 D spheres are readily identified . oIn practice + 0.25 is placed before one eye and then before other eye . oIf the eyes are balanced the patient will report that corresponding to the eye is more blurred . oAfter a balance is established between the two eyes remove prism and reduced the fog binocularly until maximum VA id obtained .