**2. Binocular oculomotricity**

**Rectus muscles**: Maintain the central fixation point, the intersection of the visual axes, projected in the respective central ocular fovea [2].

**Superior oblique muscle**: [2] Controls the cylindrical corneal dioptric power that is part of the moving mass transfer mechanism of the cornea and retina by forced convection and moves the trabecular meshwork to prevent obstructing the passage of aqueous humor [4]. The cerebral hemisphere adjusts the projected image on the contralateral eye nasal retina to the projected image on the ipsilateral eye temporal retina by contralateral eye superior oblique muscle contraction or relaxation, with the help of the other muscles to prevent torsional movement of the contralateral eye, so if the technician positions the corneal topography equipment without the contralateral eye occlusion then when turning off the light used for positioning the equipment the projected image on the contralateral eye temporal retina ceases to exist and can cause superior oblique muscle relaxation and repositioning of the eye under examination.

**Inferior oblique muscle**: Has antagonistic action to the torsional force of the superior oblique muscle to prevent cyclotorsional movement of the eye [2].

**Ciliary muscle**: controls the lens accommodation to select the depth of focus and moves its moving mass [2, 4].

**Iris**: Reduce the light diffusion in the projected image in the retina and prevents aqueous humor return when the pressure in the anterior chamber is greater than in the posterior one during the natural process of corneal cylindrical diopter power variation due to the images fusion [3–5].

**Binocular visual field**: It is the intersection of the visual fields of the two eyes. The person can focus on the tip of a pencil placed over the nasal root, this being the limit of near vision.

**Retina**: Its main function is to discretize the analog image projected on its photoreceptors, transduce it into neural signals and send them to the respective hemispheres.

### **3. Neurophysiological anatomy of natural binocular vision**

#### **3.1 Physioanatomy in the writing movement**

To facilitate the explanation of the importance of the movement of the superior oblique muscle, the writing of a person covering a calligraphic text was chosen [2]. The superior oblique muscle, when accommodating the cornea, moves the forced intraocular convection mechanism, which keeps the mobile mass in

**77**

**Figure 1.**

*transduction.*

*Visual Impairment Caused by Monovision Surgical Design*

agitation to prevent the accumulation of dehydrated metabolic residue. Due to personal habits, the forced convection mechanism is impaired and the oculomotor system starts to accumulate dehydrated metabolic residue in droplet form [2], so the older the person, the greater the amount of droplets stored and the less visual acuity. This is the inducing reason why many believe in the link between age and

**Figure 1a** was created to explain the connection of the observed visual field and its relationship with the interpretation of the image. **Figure 1a** corresponds to one of the forms used by a right-handed person, with natural vision, when covering a calligraphic text. The visual axes of both eyes converge at the tip of the pencil, so the dashed vertical line which passes at the tip of the pencil divides the writer's visual field into the right and left visual fields. The right and left visual fields are projected inverted on the retinas of both eyes, **Figure 1b**, however, on the temporal retinas of their respective contralateral eye and on the nasal retinas of their respective ipsilateral eye. Optical discs are part of their respective nasal retina, that is, the projections on the two temporal retinas are more accurate than their respective

The image projected onto the temporal retina, **Figure 1b**, is transduced to its respective ipsilateral cerebral hemisphere, **Figure 1c2**, and the image projected onto the nasal retina, **Figure 1b**, is transduced to its respective contralateral cerebral

*Diagram showing the projection of the image on the retina and its transduction to the brain. (a) Visual fields, (b) projection into the human eye, (c) image sent to the brain, 1 - ipsilateral transduction, 2 - contralateral* 

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

visual degradation.

projections on the nasal retinas.

hemisphere, **Figure 1c2**.

*Visual Impairment Caused by Monovision Surgical Design DOI: http://dx.doi.org/10.5772/intechopen.95770*

*Current Cataract Surgical Techniques*

corrective lenses.

**2. Binocular oculomotricity**

tioning of the eye under examination.

and moves its moving mass [2, 4].

limit of near vision.

hemispheres.

variation due to the images fusion [3–5].

**3.1 Physioanatomy in the writing movement**

The research group leader exercises his own eyes to solve his eye refraction problems and discusses with the researchers group the understanding of the intraocular

In this chapter we will show that the implantation technique known as IOL monovision, should be performed only if the patient accepts the act, after being informed, in writing, of the possible negative consequences that may occur to his health following cataract surgery. The difficulties in living with the symptoms acquired by a patient submitted to this surgical technique are presented, as well as the preoperative exams. Before surgery the patient was authorized by the doctor to renew his driver's license to drive motor vehicles without the use of

**Rectus muscles**: Maintain the central fixation point, the intersection of the

**Superior oblique muscle**: [2] Controls the cylindrical corneal dioptric power that is part of the moving mass transfer mechanism of the cornea and retina by forced convection and moves the trabecular meshwork to prevent obstructing the passage of aqueous humor [4]. The cerebral hemisphere adjusts the projected image on the contralateral eye nasal retina to the projected image on the ipsilateral eye temporal retina by contralateral eye superior oblique muscle contraction or relaxation, with the help of the other muscles to prevent torsional movement of the contralateral eye, so if the technician positions the corneal topography equipment without the contralateral eye occlusion then when turning off the light used for positioning the equipment the projected image on the contralateral eye temporal retina ceases to exist and can cause superior oblique muscle relaxation and reposi-

**Inferior oblique muscle**: Has antagonistic action to the torsional force of the

**Ciliary muscle**: controls the lens accommodation to select the depth of focus

**Iris**: Reduce the light diffusion in the projected image in the retina and prevents aqueous humor return when the pressure in the anterior chamber is greater than in the posterior one during the natural process of corneal cylindrical diopter power

**Binocular visual field**: It is the intersection of the visual fields of the two eyes. The person can focus on the tip of a pencil placed over the nasal root, this being the

**Retina**: Its main function is to discretize the analog image projected on its photoreceptors, transduce it into neural signals and send them to the respective

To facilitate the explanation of the importance of the movement of the superior oblique muscle, the writing of a person covering a calligraphic text was chosen [2]. The superior oblique muscle, when accommodating the cornea, moves the forced intraocular convection mechanism, which keeps the mobile mass in

**3. Neurophysiological anatomy of natural binocular vision**

superior oblique muscle to prevent cyclotorsional movement of the eye [2].

process of dehydration and rehydration of metabolic residue.

visual axes, projected in the respective central ocular fovea [2].

**76**

agitation to prevent the accumulation of dehydrated metabolic residue. Due to personal habits, the forced convection mechanism is impaired and the oculomotor system starts to accumulate dehydrated metabolic residue in droplet form [2], so the older the person, the greater the amount of droplets stored and the less visual acuity. This is the inducing reason why many believe in the link between age and visual degradation.

**Figure 1a** was created to explain the connection of the observed visual field and its relationship with the interpretation of the image. **Figure 1a** corresponds to one of the forms used by a right-handed person, with natural vision, when covering a calligraphic text. The visual axes of both eyes converge at the tip of the pencil, so the dashed vertical line which passes at the tip of the pencil divides the writer's visual field into the right and left visual fields. The right and left visual fields are projected inverted on the retinas of both eyes, **Figure 1b**, however, on the temporal retinas of their respective contralateral eye and on the nasal retinas of their respective ipsilateral eye. Optical discs are part of their respective nasal retina, that is, the projections on the two temporal retinas are more accurate than their respective projections on the nasal retinas.

The image projected onto the temporal retina, **Figure 1b**, is transduced to its respective ipsilateral cerebral hemisphere, **Figure 1c2**, and the image projected onto the nasal retina, **Figure 1b**, is transduced to its respective contralateral cerebral hemisphere, **Figure 1c2**.

**Figure 1.**

*Diagram showing the projection of the image on the retina and its transduction to the brain. (a) Visual fields, (b) projection into the human eye, (c) image sent to the brain, 1 - ipsilateral transduction, 2 - contralateral transduction.*

Then, each cerebral hemisphere receives ipsilateral hearing and the projected image on the temporal retina of the ipsilateral eye, and, if it exists, includes the image of the contralateral hand, **Figure 1c1**, in addition to receiving the image projected on the nasal retina of the contralateral eye, and, if it exists, it includes the image of the ipslateral hand, **Figure 1c2**.

Each cerebral hemisphere controls, the contralateral superior oblique muscle, **Figure 1c2** and all other ipsilateral eye muscles (the rectus, inferior oblique, ciliary, iris, superior eyelid lift), control the movements of the contralateral hand and the rotating movement of the head in the contralateral direction **Figure 1c1**.
