The Krimsky test

Krimsky test

The Krimsky test is a widely accepted method of assessing the angle of deviation in strabismic patients. The Krimsky test is a modified version of Hirschberg’s Test, based on the well-established principle of Hering’s law of equal innervation. Krimsky test procedure In the Modified Krimsky Test, the patient fixates on a penlight, and prisms are … Read more

Bell retinoscopy

Bell retinoscopy

This procedure involves the use of a shiny steel ball, typically gold or silver in color, which is attached to a stick. The examiner holds the stick along the midline, at a certain distance from the patient. This technique derives its name from a small bell that used to hang on a string and served … Read more

Nott retinoscopy:

Nott retinoscopy

Nott retinoscopy is a technique similar to MEM (Monocular Estimated Method). In Nott retinoscopy, a fixation card (typically 6/6 in size) is positioned 40 cm away from the patient’s eyes. The card can be held by the patient or mounted on a measurement scale. The subject is instructed to view the target binocularly using their … Read more

Monocular estimation method

Monocular estimation method

MEM is a dynamic retinoscopy technique involves the use of a retinoscope with a series of cards attached to its head using magnets, such as the Welch Allyn retinoscope. These cards have a central aperture that helps the examiner align their viewing axis with the subject’s visual axis. The cards contain targets, such as printed … Read more

AC/A ratio (Accommodative convergence/ Accommodation ratio)

AC/A ratio Calculated heterophoria method

Accommodative convergence/ Accommodation ratio also known as AC/A ratio, is a measurement of changes in accommodative convergence in prism diopters induced when the patient exert or relax 1 diopter of accommodation. Changes in the accommodation are either evoked by placing plus lens which relaxes accommodation or by minus which activate accommodation or when a person … Read more

Binocular balancing

After completion of monocular subject refraction, binocular balancing is performed to balance the state of accommodation between two eyes. Binocular balancing aims to balance the state of accommodation of the two eyes. The procedure ensures that a person exerts the same amount of accommodation through distance correction while viewing a near target. During monocular refraction, … Read more

Bichrome prism dissociated method

bichrome binocular balancing

The prism dissociation and alternate occlusion test are only used when both eyes have similar monocular visual acuity. If monocular corrected visual acuity is not the same for both eyes, the bichrome prism dissociated method is used. Procedure of bichrome binocular balancing Kamal ThakurLecturer (Nethradhama School of Optometry) Moptom

Alternate occlusion method: 

This differs from the vertical prism dissociation method, instead of using prisms in both eyes, eyes are dissociated using occlusion. A paddle occlude is used for occlusion of the eye (occluder which is used in the cover test) which allows to shift occlusion from one eye to another easily and rapidly. Procedure of alternate occlusion … Read more

Vertical prism dissociation method

binocular balancing test

The procedure makes use of prisms to break the fusion between two eyes. The vertical prisms of the same amount are used to maintain equal degradation of image quality which is caused by prism. Don’t use horizontal prisms, as a compensatory positive and negative fusion vergence will make it difficult to break fusion or very … Read more

Astigmatism Fan and block test

Astigmatism fan and block

The Fan and block chart is similar to an astigmatism fan chart but additionally includes a block which contains an arrow at the center and two blocks of the line adjacent to the arrow which are perpendicular to one another. This additional block makes this test easier for the patient. Before reading procedure read optics … Read more