**3.2 Eye exercises**

The same interpretation of the oculomotor action of writing covering a calligraphic text, exposed through the diagram shown in **Figure 1**, is used in the analysis of the focus of a person's gaze, at the lateral limit of his binocular vision, the tip of the finger of his hand, very near to the nasal root, **Figure 2**, as children do in their initial oculomotor development. In **Figure 2a**, the right eye is diagrammed, positioning its visual axis tangent to the nasal root and intercepting the visual axis of the contralateral eye at a focus point common to both eyes, on the middle finger, of the contralateral hand, and on the **Figure 2b**, the left eye is diagrammed, positioning its visual axis tangent to the nasal root and intercepting the visual axis of the contralateral eye at a focus point common to both eyes, on the middle finger, of the contralateral hand. So:


#### **Figure 2.**

*Diagram showing the lateral limits of the binocular visual field. (a) left binocular limit, (b) right binocular limit.*

**79**

*Visual Impairment Caused by Monovision Surgical Design*

**4. Cataract surgery with monovision IOL**

As [7] in monovision one eye (usually the dominant eye) is corrected for distance and the other eye is corrected for reading and according to [8] a lens set to far distances is implanted in your dominant eye, while a lens set to near distances is implanted in your non-dominant eye. It works because your brain automatically adjusts your visual system to achieve clear vision when you are focusing on near and

This surgical technique uses pathological ocular dominance to maintain it and does not encourage its correction. In [2] it was demonstrated that in natural binocular vision, ocular dominance is alternated between the two eyes. But in [9] it says "If a strong degree of dominance is not apparent in a dominant eye test, it's more likely a person has mixed ocular dominance (*also called alternating ocular dominance*), where one eye is dominant for certain functions or tasks, and the other eye is dominant at different times", in addition to citing two criteria to determine ocular dominance, but under the hypothesis of alternating ocular dominance, that is, it

In the work development, in the research group, it was found that in a simple frontal photo, a selfie, it is possible to perceive the result of pathological ocular dominance, but it is necessary to be sure that the photo is really frontal [10], see photo of **Figure 3**, because vicious ocular dominance can cause slight ocular deviation. Another way is to focus on the pencil tip that moves slowly to the nose root. The eye that keeps focusing on the pencil tip is the the dominant eye and the contralateral eye moves away quickly in its temporal direction, losing the focus point is the nondominant eye, because who has natural binocular vision keeps both eyes focused on the pencil tip until it reaches the root of the nose effortlessly. The pathological ocular dominance is known as ocular dominance and in this chapter it is addressed only in

If a person, with one eye, sees the nearby objects well and with the contralateral eye sees the distant objects well, this situation was built through the convenience and personal habits, that is why, in this chapter, it is called ocular dominance, which is constructed involving eye shape and movement, in addition to the construction of neural communication, therefore, its surgical reproduction is impossible without the possibility of binocular vision. In this chapter, ocular dominance after monovision surgery is called dichotomous ocular dominance. Considering scientific knowledge, two surgical options are presented only for comparison with monovision surgery:

• **Bilateral monofocal intraocular lenses**: In this chapter it is considered that there are two monofocal lenses so that the eyes can focus on distant objects, although corrective lenses are required for reading. In this case, the distant focus is a known operational state of equilibrium, analogous to the state existing before surgery, and for reading, it is a state of temporary equilibrium, because of the use of corrective lenses, but both eyes focus simultaneously on

• **Bilateral bifocal intraocular lenses**: In this chapter, it is considered that there are two lenses with two distinct optical powers so that the eyes can focus on far and near distant objects without the use of corrective lenses. In this case, the far focus and the near one are two well-known operational states of equilibrium, analogous to their corresponding states existing before the operation, because the two eyes simultaneously focus on common distances at different times.

same distance in both equilibrium states as well as images fusion.

identifies the natural ocular dominance acting alternately in both eyes.

its connections in planning and sequelae related to monovision surgery.

*DOI: http://dx.doi.org/10.5772/intechopen.95770*

**4.1 Etiopathogenesis of monovision**

distant objects [8].
