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MYOPIA

MYOPIA. MYOPIA : PROGRAM. Myopia: program I. Generalities Definition Etiology Epidemiology Classification: According to magnitude Clinical. Myopia: program II. Myopia simple: Characteristics Clinical exam Prescription criteria. Factors: Age Anisometropia Binocularity

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MYOPIA

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  1. MYOPIA

  2. MYOPIA : PROGRAM

  3. Myopia: program I • Generalities • Definition • Etiology • Epidemiology • Classification: • According to magnitude • Clinical

  4. Myopia: program II • Myopia simple: • Characteristics • Clinical exam • Prescription criteria. Factors: • Age • Anisometropia • Binocularity • Control of myopic progression

  5. Myopia: program III • Degenerative myopia: • Characteristics • Clinical examen • Prescription criteria. Factors: • Type of optical compensation • Pseudomyopia: • Characteristics • Clinical exam • Prescription criteria

  6. Myopia: program IV • Nocturnal myopia: • Characteristics • Treatment

  7. MYOPIA: GENERALITIES

  8. Myopia: Generalities I • 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

  9. Myopia: Generalities II • The etiology of myopia depends on diverse factors. Such as: • Hereditary • Magnitude • Sex • Work NV • Diet • Etc.

  10. MYOPIA: CLASSIFICATION

  11. Myopia: classification I • 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

  12. Myopia: Classification II • Clinically: • Simple myopia • Magna, degenerative, or pathological myopia • Pseudomyopia • Noctunal myopia

  13. Myopia: classification III 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 18-20 years of age it has few variations

  14. Myopia: Classification IV 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

  15. Myopia: Classification V • Pseudomyopia • Result of an accomodative spasm • Subjective exam is more negative than the retiniscopy • Nocturnal myopia • VA reduction in conditions of low illumination

  16. MYOPIA: SIMPLE MYOPIA

  17. Simple myopia: Characteristics I

  18. Simple myopia: Characteristics II • 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

  19. Simple myopia: Characteristics III • 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

  20. Simple myopia: Symptoms and signs • 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

  21. Simple myopia : Clinical exam • 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

  22. Simple myopia: Clinical treatment I • 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

  23. Simple myopia: Clinical treatment II • Anisometropia: • Up to 8-10 years of age: try to prescribe for the anisometropia • > 10 -12 years of age: prudence in the prescription. Possible existence of monovision

  24. Simple myopia: Clinical treatment III • 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

  25. MYOPIA: MYOPIA DEGENERATIVE

  26. Degenerative myopia: Generalities I • 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

  27. Degenerative myopia: Generalities II • 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%

  28. Degenerative myopia: Generalities III • 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

  29. Degenerative myopia: Clinical exam • 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.

  30. Degenerative myopia: Clinical treatment • 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

  31. MYOPIA: PSEUDOMYOPIA

  32. Pseudomyopia: Generalities I • 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

  33. Pseudomyopia: Generalities II • 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

  34. Pseudomyopia: Clinical exam I • 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

  35. Pseudomyopia: Clinical exam II • Binocularity: • Can be associated with exodeviations (secondary condition pseudomyopia) • Can be associatated with endodeviations (primary condition pseudomyopia)

  36. Pseudomyopia: Clinical treatment • Treatment: • Negative minimum • If prescription: use mainly in DV • Norms of visual hygiene • Visual exercises to relax accomodation

  37. MYOPIA: NOCTURNAL MYOPIA

  38. Nocturnal myopia: Generalities • 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

  39. Nocturnal myopia: Clinical treatment • Specific Rx for nocturnal activities • Tends to be sufficient with a prescription of -0,75 or -1,00 D

  40. MYOPIA: CASES

  41. Myopia: case 1-I • 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.

  42. Myopia: case 1-II • 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

  43. Myopia: case 1-III • 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

  44. Myopia: case 1-IV • Complete diagnostic of the case • Treatment proposed and plan of revisions • Possible evolution of the condition

  45. Myopia: case 1-V • 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

  46. Myopia: case 1-VI • 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

  47. Myopia: case 1-VII • 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

  48. Myopia: case 1-VIII • Possible evolution of the condition: • Progression of the myopia

  49. Myopia: case 2-I • 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.

  50. Myopia: case 2-II • 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

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