Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda)

Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda)
Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) MYOPIA The objective of this section is: determine the prescription criteria in cases with myope subjects. This section is structured for: 3 hours of theory One task outside of the classroom It does not present directly associated practice. The students should simultaneously continue practicing clinical refraction techniques. The methodology of the class will be different according to the concrete objectives in the distict sections and it will be explained in each of them.

Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) MYOPIA : PROGRAM

Myopia: program I Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Generalities Definition Etiology Epidemiology Classification: According to magnitude Clinical In the Generalities section, the objective is to refresh the previous knowledge that the students possess with regards to these aspects, explained in the corresponding module in the Generalities of ametropias. As a result, it doesn’t have to be an attended class. Students can count on between 1 and 2 hours of personal work in order to refresh previous knowledge. We recommend working in groups of 3-4 students with the following procedure: Hand in an outline of the section similar to the one in the slide in the generalities section. Recommend a first step that consists in refreshing previous knowledge. An interview between the professor and each of the groups during which strong and weak points of the recuperation realized up to that moment will be detected. Elaboration alongside amplification for each group. With the recommend books in the theme’s bibliography and some web pages the students can improve upon their knowledge. Hand in a definitive draft to the professor who can decide whether it forms a part of the system of evaluation or not. Hand in a later, corrected draft indicating the quality of the task and evaluating the capacity for synthesis.

Myopia: program II Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Myopia simple: Characteristics Clinical exam Prescription criteria. Factors: Age Anisometropia Binocularity Control of myopic progression The advancement of the main contents of the module will be dedicated to the clinical attention to different types of myopia. It will begin with simple myopia (the most prevalent).

Myopia: program III Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Degenerative myopia: Characteristics Clinical examen Prescription criteria. Factors: Type of optical compensation Pseudomyopia: Clinical exam Prescription criteria Next, we will address the theme of degenerative myopia which we will also find to be named magna or pathological. Afterwards pseudomyopia which, just as its name indicates, refers to those cases in which the subject demonstrates myope visual behavior when in reality the patient is not myope.

Myopia: program IV Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Nocturnal myopia: Characteristics Treatment We will finish the exposition of the types of myopia by looking at nocturnal myopia, which only presents itself in poorly lit conditions.

Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) MYOPIA: GENERALITIES

Myopia: Generalities I
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Myopia: Generalities I Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Refractive condition in which the image of an object at a distance does not form on the retina but focuses in front of the retina. Structural causes of myopia could be: Excessive axial longitude of the eye Excessive power of the eye Error in the relationship between axial longitude and power The slide is to be utilized to remind the students of previously acquired concepts and of previous tasks on myopia.

Myopia: Generalities II
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Myopia: Generalities II Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) The etiology of myopia depends on diverse factors. Such as: Hereditary Magnitude Sex Work NV Diet Etc. Diverse factors related to the etiology of myopia are known to exist. In addition, the distinct types of myopia show different etiological factors. This is why they are dealt with in greater detail in the corresponding sections.

MYOPIA: CLASSIFICATION
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) MYOPIA: CLASSIFICATION

Myopia: classification I
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Myopia: classification I Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) According to the magnitude of the myopia: Low myopia: between -0,25 and -3,00 D Moderate myopia: between -3,25 and -6,00 D High myopia: between -6,25 and -10,00 D Very high myopia: above -10,00 D A simple form of classifying myopia is done by paying attention to its magnitude. Despite the diversity of criteria, we can say that: Low myopia: from -0,25 to -3,00D. Obviously the affect on the VA in DV will depend on the magnitude of the myopia. In general: 20/25 vision can be obtained (or even 20/20 though with difficulty) in the cases of myopias from -0,25 to -0,50 without compensated. 20/40 or 20/30 in cases of myopia near 1,00D. The VA can be 20/200 or 20/100 in uncorrected myopias of 2,00D For myopias of greater magnitude the uncorrected VA starts to fall below 20/200 In this range of ametropia the VA in NV will be seen little affected or not affected at all. Moderate myopias: from -3,25 to -6,00D. The VA in DV is, in all cases, below 20/200 or 20/400.The VA in NV will always be preserved, and when the work distance diminishes. Myopias above -6,00D. Low VA, with correction, as much with near vision as with distance vision. Associated pathologies of the ocular sphere.

Myopia: Classification II
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Myopia: Classification II Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Clinically: Simple myopia Magna, degenerative, or pathological myopia Pseudomyopia Noctunal myopia Much more useful than the previous classification is that which is shown in the present slide. We say that it is a clinical classification since it concentrates on diverse aspects of the patient’s visual behavior and allows for understanding of his/her visual symptoms. In addition, each of these types of myopia have general lines of recommendation for prescription criteria.

Myopia: classification III
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Myopia: classification III Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) SIMPLE MYOPIA Most common type of myopia Is recognized by: Good VA in DV with correction Absence of structural anomalies of the ocular sphere (no pathologies) Retinoscopy  subjective Progresses limitedly School age: 0.50 D/year After years of age it has few variations Simple myopia is the most prevalent in the population and is characterized by: It is a functional myopia. Due to logical variations in the population’s ocular parameters, among other causes. It does not provoke the appearance of an associated ocular pathology; consequently the VA will be normal with the prescription for the refractive error. The value of the retinoscopy is very similar to that of the subjective. It presents a progression in magnitude (important general characteristic) until the beginning of adulthood.

Myopia: Classification IV
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Myopia: Classification IV Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) MAGNA OR DEGENERATIVE MYOPIA Secondary to an excessive axial longitude of the eye Associated to alterations or degeneration of certain ocular structures With the passage of time the VA can be diminished Alterations to the posterior pole (mainly): Myopic cone Loosening of the retina Macular alterations Etc The next type of myopia is degenerative, magna, or pathological myopia. It is secondary to the excessive growth of the eye (excessive axial longitude) that provokes: Elevated value of myopia. This magnitude can be very variable but we can speak about some possible values that oscillate from 6 to 8D and others that can be over 30D. Secondary ocular alterations (from which fact the name degenerative or pathological is derived). Among the main issues we point out in this section are those that affect the funduscopy and can be observed with the opthalmascope: Myopic cone: secondary to an excessive growth of the ocular sphere. The anatomical structures of the eye are excessively stressed and the retina (with its pigment epithelium) does not reach the emergency zone of the nervous fibres. Loosening of the retina: more prevalent as age progresses and depending on the magnitude of the myopia. It is secondary to the excessive axial longitude and to the retina’s consequential difficulty in covering all of its area. Macular alterations: mainly degeneration of the tissue in this zone. Etc.

Myopia: Classification V
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Myopia: Classification V Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Pseudomyopia Result of an accomodative spasm Subjective exam is more negative than the retiniscopy Nocturnal myopia VA reduction in conditions of low illumination Just as it’s name suggests, pseudomyopia is that which makes it appear as if the patient has myopia (since the visual behavior is that of a myope and the subject shows the characteristic symptoms of myopia) when in fact this is not the case. This is proved when the objective analysis of the refractive defect through the retinoscopy is done and myopia is not detected. It’s ETIOLÓGICA cause is a small spasm in the Ciliary muscle. A greater reflection on the value of refraction is important in these cases in which the Ciliary muscle spasms, since confusion can exist: If the person is really emmetrope (or almost), when there is a Ciliary spasm it augments the power and consequently the person becomes myope. These are cases in which the value of the retinoscopy is around 0,00 D and the subjective exam can vary, but in general is between -0,50 and -2,00 D. If the person is myope, when the Ciliary spasm appears it augments the ocular power and consequently the person becomes more of a myope. The magnitude of the spasm also tends to oscillate, with greatest frequency between 0,50 and 2,00 D. An example: a person whose retinoscopy gives a value of -1,25 D but who, in the subjective exam, does not reach a good VA until we put the -2,25 D lense before him/her. If the person is hypermetrope, the Ciliary muscle spasm increases the ocular power and consequently provokes a decrease in the hypermetropic refraction. We can find cases in which the value of the retinoscopy is +3,50D but because of the spasm mentioned, the person will not tolerate a prescription higher than +2,00 (without losing VA). This lastecase is known as latent hypermetropia which is addressed in more detail in the Hypermetropia module. Nocturnal myopia is that which only manifests itself in conditions of low illumination and that provokes, in certain people, difficulties, for example, driving at night.

Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) MYOPIA: SIMPLE MYOPIA

Simple myopia: Characteristics I
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Simple myopia: Characteristics I Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Factors associated with the prevalence of simple myopia Age 2%-5% at 6 years of age 25%-35% in young adults Sex Greater in women Race Greater in white races, Japanese, Jews, and Chinese. Lesser in darker races Reading and education Increases when the reading and educational levels increase Occupation Greater in cases which consist of activity in NV In order to introduce the theme of myopia we make brief reference to some characteristics and epidemiological aspects. About age, we point out that there are various studies that deal with the prevalence in the population and that will depend a lot on the group chosen. Nonetheless, the increased prevalence with the passage of time is common in all of them. It is also known that the earlier (agewise) that the myopia begins the greater the magnitude that it will reach. In all cases of all ages there is greater prevalence in women. The difference is principally greater around the age of puberty. Epidemiological observations suggest that the visual activity influences the development of the refractive error and a strong relationship has been discovered, remarkably consistent and dosis dependent, between myopia and work in NV.

Simple myopia: Characteristics II
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Simple myopia: Characteristics II Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Age School age: At 6 years of age: 5% myopes At 18 years of age: 25-35% myopes 20-60 years of age: stabalization > 65 years of age: do not forget the relationship between nuclear cataracts and myopia A little more detail about the refractive variations that can be expected with age in people with simple myopia: In small children, before starting school, there aren’t a great number of myopias When the schooling period finishes the percentage of myopes increases markedly. In addition, point out that not only are the number of myopes increased but also that during the period between 6 and years of age, myopias that do appear progressively increase in value with the passage of time. Emphasize that this progression is characterized by a large variability between people. After the age of 20 (approximately) the refractive defect stabalizes or the variations are minimal. Emphasize that when old age begins, the presence of cataracts tends to increase markedly. The senile cataract is opacification of the crystalline and a densification of the crystalline can also exist (increase in the index of refraction). Consequently, the ocular power increases and appearance of or increase to the myopia is produced.

Simple myopia: Characteristics III
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Simple myopia: Characteristics III Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Possible risk factors for the development of myopia: Family history of myopia Emmetropia at pre-school age Astigmatism against the rule Altered accomodative function Endophoria in NV Prolonged work in NV and at very short distances Obstruction in the formation of images during the first few years In the slide some indicators that a child or youth could develop myopia are shown.

Simple myopia: Symptoms and signs
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Simple myopia: Symptoms and signs Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Symptoms Blurry vision in DV Rarely symptoms in NV Signs Blinks to reduce the palpebral aperture Good VA in NV Mydriasis Exodeviation Bringing glasses closer The symptoms that myope subjects show without correction or with a hypercorrection tend to be easily recognizable since they refer to a reduction of vision in DV, maintaining adequate near vision. The clinical signs that can coexist are: Reduction of the palpebral aperture through blinking in order to improve the VA thanks to the increase of the depth of the eye’s focus. It is frequent that myopes present pupillary diameters slightly greater than is expected for the age. In addition, less accomodation from close up makes the near myosis slightly less. We must remember the concept of the proximal triad (accomodation-convergence-pupillary diameter) when near objects are seen. Given that a myope in NV accomodates less than an emmetrope it also results in a lesser response from the accomodative convergence. This can provoke endodeviations of variable grades, mainly from close up. A hypercorrected myope demonstrates an habitual gesture of bringing the glasses closer to the eyes, and he/she does it with great frequency. This, due to a decrease in the distance of the vertex between the negative lenses and the eye, increases the effective power of both. This gesture provokes a slight improvement in the retinal image and of the VA.

Simple myopia : Clinical exam
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Simple myopia : Clinical exam Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Retinoscopy and subjective have similar value With the adequate Rx the VA tends to reach 20/20 or even 20/15 Absence of related anomalies in the funduscopy. If the subject has never worn glasses he/she could show a reduced amplitude of accomodation for his/her age Points to keep in mind during the clinical exam are: The value of the retinoscopy and the subjective are similar (this has already been previously explained) Do not provoke alterations to or degenerations of the ocular sphere, with which the VA will be good with the appropriate prescription. If a myope, let’s imagine, of -2,00 has never worn glasses, he/she hardly realizes an accomodative exertion when using NV. This is why it is possible that, when we give a prescription for his/her refractive error and we determine his/her amplitude of accomodation, we find it low for his/her age. We are demanding that the patient use an accomodative capacity that he/she has never needed. In these cases it is appropriate to allow for a period of time so that the person can adapt to the new prescription. In general the accomodative capacity normalizes itself after 2-3 months.

Simple myopia: Clinical treatment I
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Simple myopia: Clinical treatment I Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Age: Children < 2 years of age: hypercorrect by 1-2 D Children up to 5-years-old (pre-schoolers): hypercorrect by 0,5-1 D From 6 to 40 years of age: avoid hypercorrections. Evaluate: Visual needs Binocularity > 40-years-old: Precaution if he/she has never had a myopic Rx before The clinical treatment of simple myopia can be approached by paying attention to distinct factors, the first of which is the age of the individual myope. The child’s visual world is one of close distances and they tend to be closer the younger the child. This is why we can recommend light hypercorrections at these ages. There is some controversy regarding the necessity and utility of the aforementioned hypercorrection. In the period from 6 to years of age it is necessary to make reference to the need to avoid myopic hypercorrections. In young patients we must be careful not to prescribe for more myopia than the person shows. Frequently it is easy for the individual to refer to greater comfort during the subjective exam with a grade of myopia a little higher (0,50 D for example) due to the fact that this -0,50 provokes a greater contrast of the letters of the optotype for DV. Remember that any increase of -0,25 in the subjective exam has to be accompanied by an increase in the power of resolution (VA); judging by which, if it only provokes greater contrast, this refractive change is not necessary. > 40 years of age: At this age, the same considerations as in the previous section are valid. We emphasize, in addition, that a myope normally, uncorrected or hypercorrected, at this age shows better near vision than expected. The moment a prescription is made for the total myopia in far vision, it will inevitably provoke a loss of comfort in NV.

Simple myopia: Clinical treatment II
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Simple myopia: Clinical treatment II Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Anisometropia: Up to 8-10 years of age: try to prescribe for the anisometropia > years of age: prudence in the prescription. Possible existence of monovision Giving some prescription guidelines when the myopic graduation is accompanied by anisometropia is difficult and depends on various factors: Previous anisometropic prescription and good level of comfort found The age of the subject, which is related to the plasticity of the visual system and tolerance of certain prescriptions The level of the anisometropia Binocularity that can go, when anisometropia exists, from nonexistent to appropriate and stable We have noted down some general guidelines: In children up to 8 years of age it will be appropriate to maintain the anisometropia in the prescription in order to stimulate adequate development of the visual system. We must remember, nonetheless, that the myopia is not such an amblyogenic factor like hypermetropia since when one eye is more myope than the other it tends to rely on itself first for visual tasks in NV, which permits its stimulation and development. As years pass, we must be more prudent in the prescription and basically pay attention to the individual’s previous prescription and level of comfort with the new prescription.

Simple myopia: Clinical treatment III
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Simple myopia: Clinical treatment III Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Binocularity: Exodeviations: Total Rx for general use. In young subjects with exotropia: evaluate a possible slight hypercorrection. Endodeviations: avoid hypercorrections. In NV try a slight hypocorrection From the point of view of binocularity, myopia can be associated with: Latent exodeviations (exophorias) or manifest exodeviations (exotropias). Some reflections on this topic are necessary: If a patient shows an exodeviation without correction and a myopic refractive error: the optical compensation for the defect will diminish the deviation, mainly in near vision. With the compensation, the subject will accommodate more up close than without it and, consequently, the angle of deviation will decrease. If a patient presents an important exodeviation with the appropriate myopic compensation: the constant use of the prescription is recommended in order to keep accomodation active. In some cases, like the one shown in the slide of young myopes with exotropia, a slight hypercorrection (<2 D) can be good in order to stimulate binocular vision. There are only two recommendations in these cases: (1) the hypercorrection must facilitate the existence of binocular vision since if not the hypercorrection does not have any reason to be; and (2) we must not compromise the visual comfort in near vision. Latent endodeviations (endophorias) or manifest deviations (endotropias). To keep in mind: When there is an endodeviation in the myope subject without correction the endodeviation will increase, mainly in NV, the moment the subject puts on glasses. Hypocorrections are advisable in NV as long as they permit comfort and binocularity. When the endodeviation appears the moment the optical compensation is in place, a hypocorrections in NV may also be necessary.

MYOPIA: MYOPIA DEGENERATIVE
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) MYOPIA: MYOPIA DEGENERATIVE

Degenerative myopia: Generalities I
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Degenerative myopia: Generalities I Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Elevated myopia associated to pathological degenerative changes mainly in the posterior segment of the eye Abnormally large axial longitude Ocular complications increase with age Frequent cause of legal blindness In the Classification section we have already made reference to degenerative myopia and its etiology. Just remind students that ocular complications tend to increase with the magnitude of the myopia (a myopia of -10D is not the same as one of -25 D) and with the individual’s age. Thus, we can find a 15-year-old myope with ocular structures within the normal range but when he/she is 55 some of the aforementioned degenerations will be present. In some countries, it is a frequent cause of legal blindness.

Degenerative myopia: Generalities II
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Degenerative myopia: Generalities II Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Etiology/risk factors: Family history Prematurity and low weight Albinism Mental retardation Certain ocular pathologies Age of beginning: 0-5 years of age: 31% 6-11 years of age: 61% 12 or more years of age : 8% In the slide some factors that collaborate and coexist with high magnitude myopia are shown.

Degenerative myopia: Generalities III
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Degenerative myopia: Generalities III Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Symptoms:  VA in DV, even with the best refraction: From problems in the posterior segment Minifying effect of the lenses (-) Good VA in NV but at reduced distances Discomfort with the glasses: Peripheral distortion Weight Chromatic aberration Minification of the environment With respect to the symptoms that people with elevated myopia can possess: When they don’t wear the graduation: Very low VA at all distances. This condition limits daily life in important ways. They can see in NV but at very reduced distances (inferior to 10cm). They obtain this VA through the increase of the size of the text thanks to the reduction of the distance of observations. When they wear the graduation: It is frequently the case that they do not achieve a good VA. This happens because of the previously mentioned possible degenerations of the posterior pole and/or because of the minifying effect of the negative lenses. A lense of -15D will permit the formation of a clear image in the retina of a myope of -15 D, but, with a considerable reduction of the size of the image. This reduction will be greater the farther from the eye the lens is placed (from the principal object plane). This effect is reduced with the use of contact lenses. Elevated myopes recount that they can have good vision in primary position, but in other positions they experience distortion of space. This effect disappears with the use of contact lenses. The optical compensation of myopes has diverse obstacles and one of them, an aesthetic obstacle, is the thickness of the lenses in the glasses. It is because of this that they tend to get prescriptions in materials with high indexes of refraction which will allow lesser thickness. This brings with it, as a side-effect, heavier glasses and the perception of the chromatic aberration.

Degenerative myopia: Clinical exam
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Degenerative myopia: Clinical exam Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Signs: Occasionaly exophthalmos VA  with the best refraction More negative retinoscopy than the subjective Vertex distance critical during the subjective Anterior segment: Flatter and thinner cornea Mydriasis Deep anterior chamber Posterior segment:  relationship cup/disc (in the ophthalmoscopy) Myopic cone Posterior staphyloma Etc. The most important point to have present in the refraction are: Difference of value between the retinoscopy and the subjective. When we realize the retinoscopy we do not exactly locate the visual axis. In the zone in which we realize the retinoscopy there could be a posterior staphyloma (loosening of the ocular sphere because of the loss of rigidity of the structures) and this will imply a more elevated refractive defect. Effect of the distance of the vertex since the prescription varies depending on the distance at which the glasses are put on. This happens with all ametropes, but it begins to have clinical relevance starting after 4 or 5 D. It is known that a myope that, in glasses, at a traditional vertex distance of 12mm, shows a graduation of -5,00D and needs to use, in contact lenses, a power of -4,75D. When these differences in elevated ametropes are evaluated they can cause very important errors. Accepting that elevated myopes tend to wear their glasses pretty close to their faces (reduced vertex distance) it is necessary to realize the refraction at this distance or to keep it in mind.

Degenerative myopia: Clinical treatment
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Degenerative myopia: Clinical treatment Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Avoid hypercorrections If prescribing glasses: control the vertex distance Importance of prismatic effects in secondary sight positions Contact lenses: Less distorted vision More accomodative demand in NV In the slide, some reflections to keep in mind regarding the clinical treatment of cases of elevated myopia are shown.

Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) MYOPIA: PSEUDOMYOPIA

Pseudomyopia: Generalities I
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Pseudomyopia: Generalities I Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Value of the subjective exam is more negative than the that of the retinoscopy Possible spasm of the Ciliary muscle Do not confuse pseudomyopia with myopic hypercorrection In the Classification section we have already addressed the concept of pseudomyopia: the condition in which the patient behaves like a myope when really he/she is not (or the patient behaves as if he/she were more myopic than in reality). It is believed that, among other factors, it can be the side-effect of a spasm in the Ciliary muscle.

Pseudomyopia: Generalities II
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Pseudomyopia: Generalities II Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Etiology: Spasm of the Ciliary muscle after tasks in NV Exodeviations Effects of medication Inadequate work conditions in NV Symptoms:  VA in DV (constant or intermittent) Asthenopia in NV Apart from mentioning the spasm in the Ciliary muscle, other etiological possibilities are: Exodeviations. When a young person has an exodeviation he/she will try to realize more accomodation with the objective of dragging along a certain grade of convergence that will help him/her maintain the stability of binocular vision and to avoid diplopia. With time, this greater accomodative exertion will not be comfortable for the patient. Certain systemic and/or ocular medications can act on the nervous fibers of the Ciliary muscle and can provoke an accomodative response that is greater than necessary. Reduced work distances are also considered important etiological factors (in that an elevated accomodative stimulus is maintained during prolonged periods of time) as well as inadequate postures and lack of illumination. With the symtomology, point out that patients can present visual fatigue in NV, an infrequent symptom in cases of uncorrected myopia.

Pseudomyopia: Clinical exam I
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Pseudomyopia: Clinical exam I Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) VA  in DV Retinoscopy: Can fluctuate Subjective: More negative than in the retinoscopy The VA does not justify the refractive changes Accomodation: With the Rx of the subjective it can seem like the amplitude of accomodation is reduced In the clinical exam we point out the fluctuation of the results. Even the VA, in the retinoscopy and the subjective exam, can present fluctuations.

Pseudomyopia: Clinical exam II
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Pseudomyopia: Clinical exam II Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Binocularity: Can be associated with exodeviations (secondary condition pseudomyopia) Can be associatated with endodeviations (primary condition pseudomyopia) Frequently, binocularity can be slightly affected. In this section it is important to realize two lines of thought since they can determine the choice of the best clinical treatment. So we have: Pseudomyopia associated with exodeviations. In these cases pseudomyopia can be a secondary condition to the binocular problem. With the aim of bringing about more convergence in an exodeviation the visual system can opt to realize a hyperaccomodation (which will provoke a greater accomodative convergence and will help to improve binocularity). In cases like this, pseudomyopia will continue existing until steps are taken towards repairing the binocular problem which is the primary visual cause. Pseudomyopia associated with endodeviations. In these cases there tends to be a hyperaccomodation (pseudomyopia) as the main visual dysfunction. Accomodating more than necessary will provoke an excess of accomodative convergence which will manifest itself in the form of endodeviation. In this hypothesis as well, the optometric action should be aimed at resolving the primary cause, which is the pseudomyopia or the hyperaccomodation.

Pseudomyopia: Clinical treatment
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Pseudomyopia: Clinical treatment Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Treatment: Negative minimum If prescription: use mainly in DV Norms of visual hygiene Visual exercises to relax accomodation The treatment of the pseudomyopia is focused on the points shown in the slide: If the VA is very affected or impedes the subject from realizing daily activities, the negative minimum can be prescribed, which will offer a certain level of visual acuity. It is important to insist that use of the glasses must be unique to activities that require a good discrimination in DV and try to avoid their use in situations with near distances. One of the principal ETIOLÓGICAS causes of pseudomyopia is reduced work distances in NV, since it inherently involves a maintained accomodative exertion. Maybe the first recommendation to keep present when dealing with a person with pseudomyopia is the need to maintain an adequate work distance and good posture during visual tasks at near distances. The possibility of recommending some visual exercises that boost the capacity to relax the accomodation of the visual system also exists. Nevertheless, it is important to emphasize that these exercises will not achieve the desired visual goals if, previously, an adequate work distance is not achieved first, just as was explained in the previous section.

MYOPIA: NOCTURNAL MYOPIA
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) MYOPIA: NOCTURNAL MYOPIA

Nocturnal myopia: Generalities
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Nocturnal myopia: Generalities Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Diminishment of VA in conditions of poor illumination that improves with contact lenses Etiology: Spherical aberration Dark focus of the accomodation Detection depends on the subject’s symptomology The definition of nocturnal myopia is given in the slide: diminishment of the VA in conditions of poor illumination which can be improved upon with the use of negative lenses. At present, the exact, main ETIOLÓGICA cause of nocturnal myopia is still unknown, as is why it only affects a small percentage of the population. The most accepted theories are: The spherical aberration of the eye increases more as the pupillary diameter increases. Obviously the pupillary diameter increases in conditions of poor lighting and this is why it is in these conditions that the most spherical aberration exists. The spherical aberration provokes a shortening of the eye’s real focal distance, or, an increase in myopia, which is the same thing. In dark conditions and in the absence of visual stimulation the accomodation does not totally relax if not adopt an alert position that is calculated between 0,75 and 1,25 D of accomodative response. It is believed that this could be another factor that contributes to the appearance of nocturnal myopia. Nevertheless, insist that the causes written above do not explain why it does not appear in more people.

Nocturnal myopia: Clinical treatment
Óptico de Atención Primaria (Tahoma 10 negrita y alineado izquierda) Nocturnal myopia: Clinical treatment Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Specific Rx for nocturnal activities Tends to be sufficient with a prescription of -0,75 or -1,00 D The prescription criteria in cases of nocturnal myopia is merely empirical since there is no clinical test of application in existence that allows for exact determination.

Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) MYOPIA: CASES Next, two cases of myope patients are presented. The objective is to present the cases to the students and let them try to resolve the questions posed at the end during a period of 15 minutes. It might be more appropriate if they work in groups.

Myopia: case 1-I Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) MT, 13-years-old. Student. MC: Revision. Occasionally notes that he/she does not see well in DV PH: Has never worn glasses. It is his/her first visual revision (previous check-ups by the pediatrician). No illnesses or ingestions of medication. FH: Father and older brother are myopes. Maternal grandmother has cataracts. Some clarifications about the slide: MT are the initials of the patient’s name. Existing laws that protect the patient’s personal information impede revealing any patient’s name. MC: main reason for the consultation PH: personal history FH: family history

Myopia: case 1-II Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Normal VA in DV and NV: RE: 20/30+; NV: 20/20 LE: 20/25; NV: 20/20 Binocularity in habitual conditions: Cover test: DV: ORTHO NV: Low endophoria Promixal convergence: 6/10cm Results of the first clinical tests realized. We observe: The monocular VA in DV is a little reduced but is adequate in NV. This information points to the possible existence of a low myopia or a low myopic astigmatism. Habitually, when the VA is not reduced very much, a test designed to inform on the efficiency of the visual system in normal conditions tends to be realized. In this case it is appropriate to point out a low endophoria in NV (latent deviation that manifests a greater than normal tendency to converge from near).

Myopia: case 1-III Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Retinoscopy: RE: -0,50-0,50x90º LE: -50x90º Subjective DV and VA: RE: -0,50-0,25x75º; VA: 20/20+ LE: -0,50x100º; VA: 20/20+ Habitual amplitude of accomodation: RE: 8cm≈12,5D LE: 8cm≈12,5D Ocular health tests: within normal limits Some comments regarding the contents of the slide: The values of the retinoscopy and the subjective are similar; in addition, the VA improves with the value of the subjective. A test of the amplitude of accomodation has also been done. It could have been done with the result of the subjective exam, but a significant difference is not expected, given that the value of the subjective is of small magnitude. The value is normal for the patient’s age.

Myopia: case 1-IV Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Complete diagnostic of the case Treatment proposed and plan of revisions Possible evolution of the condition These are the issues that the students must try to find solutions to.

Myopia: case 1-V Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Complete diagnostic of the case Low inverse astigmatism in both eyes Low myopia in RE Endophoric tendency in NV The rest of the tests are within normal limits The diagnosis is shown in the slide. Perhaps indicate that it does not make special mention of the anisometropia since a graduation difference of 0,50D between both eyes is irrelevant and that an anisometropia is accepted as significant when the graduation difference between both eyes is ≥1,00D.

Myopia: case 1-VI Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Treatment proposed. There are two possibilities: Option A: Do not prescribe glasses Recommend sitting as close as possible to the board in class Recommend rules of visual hygiene: postures and work distance Explain the condition and desired conduct to the patient Revision in 3-4 months This case can allow for two treatment options that are shown in this and the next slide. It is important to emphasize that in low myopias it is not always essential to prescribe since the binocular VA is pretty good.

Myopia: case 1-VII Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Treatment proposed. There are two possibilities: Option B: Prescribe glasses: RE: -0,50-0,25x75º; LE: -0,50x100º Exclusive use for DV. In class when necessary to in order to pay attention to the board. Do not use the glasses while studying in NV Recommend standards for visual hygiene: postures and work distance Explain the condition and the desired conduct to the patient Revision in 4-6 months The endophoric condition that the patient presents is what makes us recommend that he/she does not use the glasses for NV.

Myopia: case 1-VIII Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Possible evolution of the condition: Progression of the myopia The age of the patient, his/her visual demands and the endophoric tendency from near makes us think about the possible progression of the myopia in the next few years.

Myopia: case 2-I Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) SE, 23 years of age. Salesman. MC: notes that he/she does not see will in DV, mainly while driving. PH: Has worn general use glasses for 10 years. The most recent pair are three-years-old. No illnesses or ingestion of medication. FH: Irrevelant. Some clarifications about the slide: SE are the initials of the patient’s name. The laws in existence protect the patient’s personal information and impede revealing any patient’s name. MC: main reason for the consultation PH: personal history FH: family history

Myopia: case 2-II Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Rx and VA are habitual in DV and NV: RE: -2,25; VADV: 20/25-; VANV: 20/20 LE: -1,75-0,50x10º; VADV:20/30+; VANV: 20/20 Binocularity in habitual conditions: Cover test: DV: Ortho NV: Low exophoria Proximal convergence: up to the nose Results of the first clinical exams realized. We observe: The VA with the patient’s normal monocular prescription in DV is a little reduced but is adequate in NV. This information points to the possibility of the small hypocorrection or a low myopic astigmatism. Habitually, when the VA is not very reduced, a test that will provide information on the efficiency of the visual system in habitual conditions tends to be realized. In this case point out that the low exophoria in NV (latent deviation that manifests a tendency to hyperconverge from near) is a normal and expected result. A proximal convergence up to the nose is considered a normal result.

Myopia: case 2-III Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Retinoscopy: RE: -2,75-0,25x180º LE: -2,25-0,50x180º Subjective DV and VA: RE: -2,50-0,25x15º; VA: 20/20+ LE: -2,25-0,50x15º; VA: 20/20+ Habitual amplitude of accomodation: RE: 9cm≈11D LE: 9cm≈11D Ocular health tests: within normal limits Some comments regarding the contents of the slide: The values of the retinoscopy and the subjective are similar; in addition, the VA improves with the value in the subjective. A test of amplitude of accomodation has also been realized that shows normal values for the patient’s age.

Myopia: case 2-IV Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Complete diagnostic of the case Treatment proposed and a plan of revisions Possible evolution of the condition These are the issues that the students need to try to resolve.

Myopia: case 2-V Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Complete diagnostic of the case Simple myopia low in AO Low, direct astigmatism in both eyes Exphoric tendency in NV The rest of the tests within normal limits The diagnosis is shown in the slide. Perhaps indicate that in this case we have not made special mention of the anisometropia because it is not significant.

Myopia: case 2-VI Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Treatment proposed: Prescribe new glasses: RE: -2,50-0,25x15º LE: -2,25-0,50x15º For general use Explain the change made New check-up in 2 years or before if new symptoms appear The treatment proposed is shown in the slide. We have recommended an update to the graduation of the glasses since the symptoms demonstrated justified it. Given that the person already wears glasses for general use, we have maintained the same guideline for their use.

Myopia: case 2-VII Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Possible evolution of the condition: Significant refractive changes are not expected until the age of prebyopia Due to the age of the patient and based on the latest visual investigation it seems that we find ourselves faced with a relatively stable refractive defect. Significant changes are not expected until the patient nears the age during which presbyopia normally appears.

Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) MYOPIA: BIBLIOGRAPHY

Myopia: bibliography Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha) Amos JF. Diagnosis and management in vision care. Butterworth-Heinemann, 1987 Milder B, Rubin ML. The fine art of prescribing glasses. (2nd edition), Triad Publishing company, 1991. Grosvenor T. Flom MC. Refractive anomalies. Research and clinical applications. Butterworth-Heinemann, 1991 Brookman KE. Refractive management of ametropia. Butterworth-Heinemann, 1996 Werner DL, Press LJ. Clinical pearls in refractive care. Butterworth-Heinemann, 2002

Myopia: Bibliography Asignatura Número y Título del tel tema (Tahoma 10 negrita y alineado derecha)

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