Because of errors arising from working off the visual axis and spherical aberration during retinoscopy, before a prescription can be issued the results obtained need to be refined during subjective refraction. The Jackson cross-cylinder is used to refine the correction for astigmatism.
Following retinoscopy and subjective refraction, binocular balancing is used to ensure that the accommodation is balanced in each eye. It corrects any extra hyperopia that may become manifest when the patient becomes binocular. Binocular balancing ensures that accommodation is balanced between th...
Accommodation relaxes in binocular single vision and therefore binocular addition may not be necessary as balancing with monocular fogging may have already relaxed accommodation maximally. However, binocular addition can be used as a final check to ensure that the accommodation is completely rela...
Presbyopia is a refractive condition in which the accommodative ability of the eye is insufficient for near vision work. It usually occurs at 40-45 years of age but may be earlier in people living in hot climates, people with short arms/working distances and hyperopes and later in people with lon...
