**5. Conclusion**

This chapter aims to show that there is no scientific reason for the use of the called monovision surgical technique, as well as to show that there are at least two scientific surgical alternatives. Two ways of ocular dominance are described, natural and pathological. Natural ocular dominance occurs according to the ocular system neurophysiological anatomy. Pathological ocular dominance is described in two forms, acquired and dichotomous. Acquired ocular dominance is known as ocular dominance and dichotomous ocular dominance, as referred to in this chapter, is characterized by surgical imposition. The three ocular dominances are described by their main functional characteristics and their consequences.

1.**Etiology of natural ocular dominance** - This ocular dominance is alternated between the eyes, so the dominate eye is the contralateral to the direction of the eye movement in relation to the head, its fixation, to reach an objective or to remain focused on a known objective, right after that, the dominant eye will be its contralateral one. This alternation of domination stimulates mainly the

**83**

**Figure 6.**

*Specular microscopy before and after surgery.*

*Visual Impairment Caused by Monovision Surgical Design*

physiological process characteristic of the action of the two superior oblique muscles. The superior oblique muscle action changes the corneal cylindrical dioptric power and sustains the sclera in opposition to the consequent variation in intraocular pressure. Then, the cornea shape change is part of the mass movement forced convection mechanism in the cornea and retina, in addition to moving the trabecular meshwork, to avoid obstructing the passage of aqueous humor. Forced convection in the cornea and retina prevents the accumulation of metabolic residue that causes refractive error in the cornea and stiffens the retina. The ocular domain alternation is a fast process and makes small changes in the natural lens dioptric power that is part of its own forced convection mechanism to prevents the metabolic residues accumulation that cause

2.**Etiopathogenesis of ocular dominance** - This ocular dominance is the result of habits that are harmful to the intraocular forced convection mechanism. Then, the refractive error caused by the dehydrated metabolic residues accumulated in the cornea, retina and lens resist the natural movement of the eyes and create vicious pathological movements, such as the saccadic movement

refractive error and consequent opacity.

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

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

#### **Figure 6.**

*Current Cataract Surgical Techniques*

**82**

**Figure 5.**

*Biometry before and after surgery.*

before and after operative conditions.

**5. Conclusion**

than before the surgery and also in relation to the contralateral eye. The anterior surface of the cornea became more regular, As already explained in several studies [12, 14–16], the intraocular metabolic residue is dehydrated and stored, making a volume with high viscosity. To eliminate this viscous volume, it is necessary, first, to rehydrate it in order to reduce the viscosity and homogenize its concentration in the mobile mass, however, the only intraocular natural rehydration process available is the agitation performed through corneal flexion [14] using images fusion. In the 69-year-old patient case, the surgery made impossible for her to fuse the images, so there is no way to eliminate the metabolic residues from the cornea significantly. **Figure 5** shows the ocular biometry before and after surgery and **Figure 6** shows the specular microscopy before and after surgery, to better understand the patient's

This chapter aims to show that there is no scientific reason for the use of the called monovision surgical technique, as well as to show that there are at least two scientific surgical alternatives. Two ways of ocular dominance are described, natural and pathological. Natural ocular dominance occurs according to the ocular system neurophysiological anatomy. Pathological ocular dominance is described in two forms, acquired and dichotomous. Acquired ocular dominance is known as ocular dominance and dichotomous ocular dominance, as referred to in this chapter, is characterized by surgical imposition. The three ocular dominances are described by their main functional characteristics and their consequences.

1.**Etiology of natural ocular dominance** - This ocular dominance is alternated between the eyes, so the dominate eye is the contralateral to the direction of the eye movement in relation to the head, its fixation, to reach an objective or to remain focused on a known objective, right after that, the dominant eye will be its contralateral one. This alternation of domination stimulates mainly the

physiological process characteristic of the action of the two superior oblique muscles. The superior oblique muscle action changes the corneal cylindrical dioptric power and sustains the sclera in opposition to the consequent variation in intraocular pressure. Then, the cornea shape change is part of the mass movement forced convection mechanism in the cornea and retina, in addition to moving the trabecular meshwork, to avoid obstructing the passage of aqueous humor. Forced convection in the cornea and retina prevents the accumulation of metabolic residue that causes refractive error in the cornea and stiffens the retina. The ocular domain alternation is a fast process and makes small changes in the natural lens dioptric power that is part of its own forced convection mechanism to prevents the metabolic residues accumulation that cause refractive error and consequent opacity.

2.**Etiopathogenesis of ocular dominance** - This ocular dominance is the result of habits that are harmful to the intraocular forced convection mechanism. Then, the refractive error caused by the dehydrated metabolic residues accumulated in the cornea, retina and lens resist the natural movement of the eyes and create vicious pathological movements, such as the saccadic movement

[17] and the cyclotorsion movement mentioned in [18]. Dominance may not be full, as mentioned in [9], dominance depends on the evaluation criteria and usually for a specific activity.

	- **Precision**: In [8] it is written that the patient may still need a pair of glasses to read small print for a few hours or to thread the needle. In the binocular view, each cerebral hemisphere receives the image projected on the temporal retina of the ipsilateral eye and simultaneously receives the image projected on the nasal retina of the contralateral eye, that is, for the more precise region of the retina, both eyes transmit neural signals twice as much to the brain, then, binocular vision is more than twice as accurate as monocular vision, with occlusion of one eye, since, in addition to having twice as many points, they are adjusted together, by the action of the superior oblique muscles, **Figure 1c**. This description combines with human perception, two eyes see better than one eye. The lack of precision is analogous to the sportsman using the sight out of alignment. The use of bilateral monofocal lenses maintains visual accuracy before surgery however one may need glasses for some activities.
	- **Sharpness**: In [8] it is written that the patient may still need a pair of glasses for nighttime driving. Analyzing **Figure 1c**, the monovision, without occlusion of the contralateral eye, is less clear, because a cerebral hemisphere receives the focused image projected on the temporal retina of the ipsilateral eye adding, as noise, without focusing, the image projected on the nasal retina of the contralateral eye and the contralateral cerebral hemisphere, receives, in focus, the image projected on the nasal retina of the contralateral eye to this cerebral hemisphere, without the region projected on its optic disc, adding, as noise, without focusing, the image projected on the temporal retina of the ipsilateral eye, that is, the patient's brain starts to receive the image focused by one eye with the addition of the defocused image of the contralateral eye. This is a form of stimulus for night blindness. The lack of sharpness is analogous to the sportsman who uses the target in smoke.

The use of bilateral monofocal lenses can superimpose images with the same dimensions increasing the neural energy transmitted to the brain however one may need glasses for some activities.

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activities.

of the wall.

adaptive power to stay alive.

must use two distinct optical powers of lenses.

*Visual Impairment Caused by Monovision Surgical Design*

• **Agility**: It is misleading to admit that the depth is given by binocular vision. If the depth depended on the simultaneous vision of the two eyes, the chicken would not be able to choose the grain of corn it eats. Animals that see their goal simultaneously with both eyes have greater agility of depth distance. The perception of distance depends on movement so astronomers are able to observe and analyze the universe with a telescope because there are movements. Those who have a natural binocular vision cannot visualize movements in static images nor can they view the stereoscopic image from photographs taken at two different points, they see two planes of images. When fixing an observation point, the alternation speed of the domain between the eyes produces dioptric powers changes in the crystallines for the rapid perception of depth but this visualization of depth is only possible up to a certain distance, from which, the brain makes use of the corneas diopter variation and for greater distances the person makes use of the head movement. After the monocular surgery there is no adjustment movement between the eyes and this may have been one of the causes of the 69 year patient's suffering. The substitution of the corneal movements for the movement of the head for depth perception the patient loses in agility because the corneas are more agile that the head, so the patient can be deprived of practicing activities that depend on agility and in transit may even cause an accident [19]. With dichotomous ocular dominance the patient may have difficulty to drive a motor vehicle, ride a bicycle and practice many sports such as tennis, ping pong, since in addition to the loss of agility, the brain receives the blurred image [20] of the contralateral eye. The lack of agility is analogous to that of sportsman with heavier equipment. An easy way to perceive the severity of the distance change problem is to use the basic principle observed by Scheinerque, in 1619, apud [1] through the using of pinhole glass [21] playing ping pong. One must be very careful when testing. The use of bilateral monofocal lenses maintains the mechanism of forced convection in the cornea, in the retina and the movement of the trabecular meshwork, fundamental for eye health, in addition to contributing to the perception of depth and has a much better result than that obtained with monovision surgery, however it may be necessary to wear glasses for some

• **Dimension**: The monocular visual field has less visual space than the visual field with both eyes. No explanation is necessary but the monocular visual field blinds part of the contralateral eye's temporal visual field. The reduction of visual space is analogous to the sportsman located on the side

To enable alternating ocular dominance if the surgery is bilateral bifocal the patient does not need corrective lenses and if the surgery is bilateral monofocal the patient must use near corrective lenses and if the surgery is monovision the patient

The vision has many secrets as nobody knows how the other sees besides nobody can compare alternatives to intraocular lenses therefore if the patient is in a very adverse situation in his vision many of the basic movements he has already lost then any improvement is profit. This was not the 69 years old patient's situation before surgery. Monovision surgery only serves to prove the human being's

The use of bilateral monofocal lenses maintains the same dimensions of the visual field before surgery, however, one may need glasses for some activities.

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

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

*Current Cataract Surgical Techniques*

usually for a specific activity.

[17] and the cyclotorsion movement mentioned in [18]. Dominance may not be full, as mentioned in [9], dominance depends on the evaluation criteria and

3.**Etiopathogenesis of dichotomous ocular dominance** - This ocular dominance is the surgical result of imposing 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 [8]. Thus, the patient is obliged to use corrective lenses in order to take advantage of his precarious intraocular force convection mechanism, before operative, however, upon waking up or when opening the eye during sleep, it causes an important impact, as it is not common to sleep with glasses, that is, the patient's brain spent 69 years adopting the direction of eye movement in relation to the head as a criterion for alternating ocular dominance and, due to the imposition of monovision surgery, in a "magic step", the focusing distance became the criterion for alternating ocular dominance without causing any disturbance for the patient. It is an alternative that should only be adopted with the permission given by the patient, after all, it is the patient who will be responsible for the administration of the after operative problems. In the case of the patient in focus, ocular dominance was imposed by the professional without the patient's knowledge, causing visual

losses in precision, sharpness, agility, expansion, among others.

• **Precision**: In [8] it is written that the patient may still need a pair of glasses to read small print for a few hours or to thread the needle. In the binocular view, each cerebral hemisphere receives the image projected on the temporal retina of the ipsilateral eye and simultaneously receives the image projected on the nasal retina of the contralateral eye, that is, for the more precise region of the retina, both eyes transmit neural signals twice as much to the brain, then, binocular vision is more than twice as accurate as monocular vision, with occlusion of one eye, since, in addition to having twice as many points, they are adjusted together, by the action of the superior oblique muscles, **Figure 1c**. This description combines with human perception, two eyes see better than one eye. The lack of precision

is analogous to the sportsman using the sight out of alignment.

surgery however one may need glasses for some activities.

The use of bilateral monofocal lenses maintains visual accuracy before

The use of bilateral monofocal lenses can superimpose images with the same dimensions increasing the neural energy transmitted to the brain

however one may need glasses for some activities.

• **Sharpness**: In [8] it is written that the patient may still need a pair of glasses for nighttime driving. Analyzing **Figure 1c**, the monovision, without occlusion of the contralateral eye, is less clear, because a cerebral hemisphere receives the focused image projected on the temporal retina of the ipsilateral eye adding, as noise, without focusing, the image projected on the nasal retina of the contralateral eye and the contralateral cerebral hemisphere, receives, in focus, the image projected on the nasal retina of the contralateral eye to this cerebral hemisphere, without the region projected on its optic disc, adding, as noise, without focusing, the image projected on the temporal retina of the ipsilateral eye, that is, the patient's brain starts to receive the image focused by one eye with the addition of the defocused image of the contralateral eye. This is a form of stimulus for night blindness. The lack of sharpness is analogous to the sportsman who

**84**

uses the target in smoke.


The use of bilateral monofocal lenses maintains the same dimensions of the visual field before surgery, however, one may need glasses for some activities.

To enable alternating ocular dominance if the surgery is bilateral bifocal the patient does not need corrective lenses and if the surgery is bilateral monofocal the patient must use near corrective lenses and if the surgery is monovision the patient must use two distinct optical powers of lenses.

The vision has many secrets as nobody knows how the other sees besides nobody can compare alternatives to intraocular lenses therefore if the patient is in a very adverse situation in his vision many of the basic movements he has already lost then any improvement is profit. This was not the 69 years old patient's situation before surgery. Monovision surgery only serves to prove the human being's adaptive power to stay alive.

After monofocal surgery, the patient cannot, without the use of corrective lenses, drive her vehicle or walk on the street safely [19, 20], in addition to losing the image fusion, blurred image [20] and, consequently, exposing herself to macular degeneration [15, 16], the increase in intraocular pressure (glaucoma) [2, 5, 10, 12] and, with corrective lenses, the 69-year-old patient suffers discomfort for read and headaches, today she prefers to abstain of read because of the great visual discomforts.

Monovision surgery and bilateral monofocus surgery do not interfere in the surgeon's fees or in the surgical costs of the clinic or health plan, in addition to not interfering in the values negotiated by the implanted lenses, so monovision surgery does not bring any financial advantage and can bring unrecoverable damage to the patient, why, in secret for the patient, use monovision surgery without any scientific basis?
