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Non surgical management of strabismus .ppt

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  • 1. Non- Surgical Strabismus management GroupPediatric ophthalmology & Strabismus Mashhad Eye Research Center Mashhad University of Medical Sciences Eye HospitalKhatam
  • 2. When it comes to treating the patient with strabismus many ophthalmologists think of surgery first, but there are several instances where the non-surgical method is best!
  • 3. What is the prescription aim? Our purpose is best visual acuity in distance versus binocular alignment  Certainly ,we want to eliminate any amblyogenic factors by using the optical correction and consider the binocular status
  • 4. Prescribing for Children • In adults, the correction of refractive errors has one measurable endpoint: the best corrected visual acuity. • Prescribing visual correction for children often has two goals: 1- providing a focused retinal image 2- achieving the optimal balance between accommodation and convergence.
  • 5. spectacle Create sharp retinal image that improve fusion Assist balance between accomodation and convergence Trend is prescribe full amount of refractive error in cycloplagia Young children normally accept the correct glass General Rules
  • 6. Search for hurt behind nose or pinch the nose or uncomfortable frame Atropinization of both eyes for 3 to 4 days in case with unable to relax accomodation Explain indication in the presence of normal vision(refractive accomodative ET) Consider full corection from infancy through pre school age spectacle
  • 7. Consider prescibe BCVA in old children Hypermetropic correction greater than +2 in esotropic patient spectacle
  • 8. case1 5 years old girl referred to clinic for strabismus. Vision: BCVA: OD:20/20,OS:20/30 Refraction:OD:+1 sph,os:+2 sph EOM:10ET with glass(far),30ET with glass(near) Fundus: normal What is your plan?
  • 9. GlassBifocal Valuable in high AC/A ratio accomodative ET Restricted in whom that were orthotropic or small angle ET in far by FCR but residual ET at near that convert to orthotropia or esophoria by additional plus lens Contraindication is amblyopia and not complete elimination of ET in near
  • 10. Start with +1 sph and increase power in step of +0.5 up to +3 sph Minimal power that convert ET to E prescribed(prevent excessive relaxation of accommodation) Success depend on proper bifocal segment Prefer straight top segment which bisect pupil or touch lower border in straight head position GlassBifocal
  • 11. Progressive as a substitute Fusional amplitude increase so reduce power stepwise until discontinue If still depend to maintain fusion during teenage year consider surgery FCR must be done semiannually and correction readjusted Goal is maximal hyperopic correction but reduce bifocal power by same amount if additional plus is necessary GlassBifocal
  • 12. High AC/A Ratio  Any uncorrected hyperopic refractive error will trigger convergenece , therefore 0.50 D ,should be full corrected  It may be possible to avoid bifocal by simply slightly overplussing the patient with a single vision correction ( +0.50 +0.75D )  Bifocal strength +2 +3.5 D  Bifocal are often eliminated in the teenage years
  • 13.  6years old boy referred to strabismus clinic due to deviation.parents notice occasional outward deviation of eyes especially after awakening.  Vision:10/10 (o.u)  Refraction:-1.00 (o.u)  EOM:15 prism diopter X(near),25 prism diopter XT(far)  Fundus:normal What is your plan? case2
  • 14. Aim of IXT treatment Reducing episodes of manifest exotropia Facilitating sensory fusion and achieving constant binocular alignment and normal stereoacuity.
  • 15. Nonsurgical management is indicated In patients with excellent control as measured by normal distance stereoacuity In young children who are at risk of developing monofixational esotropia from persistent surgical overcorrection
  • 16. In children By maintaining the potential for equal vision in each eye and preserving binocular fusion status. Nonsurgical techniques such as minus lenses and prisms can prevent or reverse early sensory anomalies
  • 17. Refractive Errors • Unequal clarity in vision represents an obstacle to fusion and can facilitate suppression, contributing to progressive loss of control in X(T). • Significant RE, especially astigmatism and anisometropia, need to be corrected.
  • 18. • All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy. • Minus lenses should be discontinued if esotropia develops. • There are studies that suggest that this treatment may induce myopia • As the child grows older, asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases
  • 19. • Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria. • Although the benefit is usually temporary, occlusion can be used to postpone surgical intervention in responsive patients • Alternate occlusion may be used in patients with equal fixation preferences • Initially the results are evaluated after 4 months of occlusion. • If the angle of deviation is decreased the occlusion should be continued and assessment made every 4 months until no further change occurs. • In case there is no improvement for 4 months, it is discontinued Occlusion
  • 20. Various Non-Surgical Therapies for Intermittent Exotropia Corrective lenses for any significant RE part time Alternate Occlusion Minus lenses Therapy Orthoptics (Including Convergence exercises) Therapeutic Base – in prisms Botulinum Toxin
  • 21. Indications for Surgery Once deterioration is documented Waiting until deterioration has relentlessly progressed may reduce the chance of obtaining an excellent surgical outcome So improving fusional states accompanied by higher surgical success rate
  • 22. The AAO PPP pediatric glass prescribing guideline
  • 23. • When hyperopia and esotropia coexist, initial management includes full correction of the cycloplegic refractive error. • Later, reductions in the amount of correction may be appropriate, based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place
  • 24. Hyperopia associated with partly of full accommodative esotropia  When hyperopia is associated with overt esotropia or ever large esophoria , a full cycloplegic correction should be prescribed  The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity  Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible  In older children 0.50 – 1.00 D should be subtracted  In some cases of acc /ET an extra + 0.50 D could make some difference to the strabismus
  • 25. Undercorrection & overcorrection Undercorrect myopia in accommodative ET rarely tolerated Slight overcorrection of myopia in IXT Optical overcorrection or under correction in treatment of amblyopia(penalization)
  • 26.  
  • 27. Ophthalmic Prism Ali Akbar Sabermoghaddam Associated professor of Ophthalmology Eye research center & Khatam eye hospital, MUMS
  • 28. Prisms bend rays toward the base. PRISMS P cm displacement 1 m = Prismatic Power (P ) apex base 100 cm X cm
  • 29. Ophthalmic Prism Prismatic power
  • 30. Ophthalmic Prism • Prisms function by bending rays of light towards the base of the prism. • The degree of bending of light depends upon the angle of incidence of light and the prismatic power.
  • 31. Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years.
  • 32. Ophthalmic Prism Corrective Prism: 1. Ground – In Prism. 2. Fresnel – On Prism (Press-on Prisms).
  • 33. Ophthalmic Prism PRESCRIBING INDUCED PRISM BY INTENTIONALLY DISPLACING THE OPTICAL CENTERS  Light traveling through the optical center of a lens encounters no prismatic power and passes through undeviated.  However, as the distance from the optical center increases, increasing prismatic power is encountered.  Prentice's rule : This is defined algebraically using the formula: Δ = hD where Δ = prism diopters , h = distance from the optical center in centimeters, and D= power of the lens in diopters.  Of note, the direction of displacement of light depends on whether the lens is of minus or plus power : - Minus lenses function as prisms held apex to apex; that is, as if the apex of the prism were at the optical center of the lens. - In other words, a ray of light traveling above the optical center encounters base-up prism power, and a ray traveling below the optical center encounters base-down prism.
  • 34.  In the mid 1960's, the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time. The first ophthalmic Fresnel prism, known as the "wafer" prism, was molded of an acrylic resin, making it much lighter and thinner than the corresponding powers of conventional prisms, thus extending the useful range of prism powers.  In 1970, the Press-OnTM prism, a Fresnel-principle prism molded in flexible plastic, was introduced to ophthalmologists. This thin, light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens.
  • 35. Ophthalmic Prism
  • 36. Fresnel – On Prism • Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic. • The prism is flexible, enabling it to conform to the base curve of the spectacle lens. • The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10, a power of 12, and in increments of 5 from 15 to 40).
  • 37. Internal Reflection Color Separation Magnification Visual acuity Fusion and stereopsis
  • 38. Ophthalmic Prism FRESNEL PRISMS  The prism is applied by pressing the smooth surface of the prism against the back surface of the spectacle lens while the lens is submerged in water.  Disadvantage of Fresnel prisms is that higher-power : - Introduce glare and chromatic aberration. - Significant decline in vision. - Minimal decline in visual acuity when using Fresnel prisms of 12 prism diopters or less
  • 39. Ophthalmic Prism Terminology a. Relieving Prism. • Action – Reduces the demand for controlling fusional vergence b. Inverse Prism. • Action – Increases the demand for controlling fusional vergence c. Yoked Prism • Action – Directs the eyes into a specific gaze direction d. Sector / Regional Prism • Action – Reduces the demand for controlling vergence in more than 1 gaze
  • 40. Ophthalmic Prism Indication : 1- Strabismus : - Comitant. - Non - Comitant (Diplopia) . 2 - Symptomatic heterophorias : Convergence training for exodeviation. 3 – presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic
  • 41. Ophthalmic Prism Prism For Deviations : 1. Exo: Base-In (BI) over either eye 2. Eso : Base-Out (BO) over either eye 3. RHT: - Base-Down (BD) over right eye - Base-Up (BU) over left eye 4. LHT : - BD over left eye - BU over right eye
  • 42. Ophthalmic Prism Prism For Head postures : 1. Left face turn Yoked prism base left 2. Right face turn Yoked prism base right 3. Chin elevation Yoked prism (BU) 4. Chin depression Yoked prism(BD)
  • 43. Chin Depression Yoked prism(BD)
  • 44. Ophthalmic Prism Adverse ( Reverse) Prism Indications : 1.To ignore the diplopic image 2.During convergence training for exodeviation: (BO Prism) 3.Cosmetics for patients who has very poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed 4.Strengthening of the weak muscle
  • 45. 1- Strengthening of the weak muscle 2- Prevent Contractures of antagonist Adverse Prism
  • 46. Inoperable strabismus : Adverse Prism Cosmetic:
  • 47. Relieving Prism  In order to move the image to where the eye is looking, thus restoring fixation and binocular vision: For diplopia  Base of the prism is placed over the weak (or paralyzed muscles)
  • 48. Relieving Prism Surgical over and under-correction:
  • 49. Relieving Prism Mild Amblyopia :
  • 50. Relieving Prism Nystagmus :
  • 51. Relieving Prism DIPLOPIA : Nerve palsies
  • 52. DIPLOPIA Myasthenia Gravis, Multiple Sclerosis , Graves Disease OBLIQUE PRISMS :
  • 53. DIPLOPIA RHT
  • 54. Symptomatic Heterophoria: Prismatic correction of exophoria Relieving Prism
  • 55. Prism for Symptomatic Heterophoria
  • 56. Prism for Symptomatic Heterophoria sheard’s criterion : Formula: prism needed=2/3 (phoria) – 1/3 (compensating fusional vergence) If a patient has 6 exophoria and base-out prism (BO) to blure is 6: 2/3 X6 -1/3X6=2  you would prescribe 2  base-in for this patient
  • 57. Prism for Other Medical - Bed-ridden patients. - Ankylosing spondylitis , - Other postural deformities.
  • 58. Ophthalmic Prism CLINICAL APPLICATIONS  In patients with tropias (small, comitant deviations) .  To ease asthenopia in patients with phorias.  Small-angle strabismus following intraocular surgery and  Residual deviations following strabismus surgery.  In most cases of superior oblique palsy, many patients will respond well to a small amount of vertical prism, with improvement in double vision and in head tilt as well.  Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement),  convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance),  divergence insufficiency (best used at distance only),  Anisometropia in the reading position (best treated with …
  • 59. Ophthalmic Prism OTHER CLINICAL USES OF PRISM  Prisms have been incorporated into contact lenses as a means of correcting vertical diplopia, but this method is only rarely used.  In some cases, prisms may be prescribed as a form of eye ‘exercise’, For example, in convergence insufficiency, the patient might be prescribed base out prism over both eyes to increase the exotropia at near.  This is typically provided as a removable Fresnel prism that is worn part of the day, with the goal of making the patient more comfortable the rest of the day when the prism is not worn.  Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity.[To correct head positions, prisms are ‘yoked’ to shift the image into the null zone area. For example, a patient who has a right head turn and a null point in left gaze would be treated with base-out
  • 60. How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS The Procedure  Estimating prism power. A good way to arrive at a starting prism power is to take the higher power prism measurement and add one-half of the lower power measurement.  For example, take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia. The higher power measurement (20) is added to half the lower power measurement (10 ÷ 2 = 5). Therefore, a 25-PD handheld prism is selected.  Testing the prism. This prism is then placed before the nondominant eye. Assuming the left eye is nondominant, the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia.  This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused.
  • 61. How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS The Procedure  If the patient is unable to fuse, another prism is selected (start with a prism one increment higher or lower—in this case either a 30-PD or 20-PD and the process is repeated until fusion occurs.  Prescribing the prism. A wax pencil is then used to draw a line directly on the outside of the spectacles, using the base of the handheld prism as a guide. The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism. For the above example, the prescription would read: ―25-PD Fresnel prism base out and down as marked.
  • 62. Ophthalmic Prism OBLIQUE PRISMS  Oblique prisms are required when trying to prescribe a single Fresnel prism for a combined vertical and horizontal deviation. Vector addition is used to combine horizontal and vertical prism. For example, combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a, b, andc, with c the hypotenuse, a2 + b2 = c2). In this case, 52 + 52 = c2 = 50; so, c = √50. Thus, 7.1 Δ of Fresnel prism may be prescribed base up and out in the 45° meridian. More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles, or more practically by measuring the combination of vertical and horizontal prism in the lensmeter. When prescribing a combination of vertical and horizontal prism for ground-in prism, these calculations are not necessary, as most opticians prefer to be given the horizontal and vertical components separately.
  • 63. OBLIQUE PRISMS
  • 64. How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS CASE ONE: A 75-year-old woman with Graves disease complained of diplopia.  Motility testing showed 25 PD of left hypertropia and 10 PD of esotropia.  A 30-PD handheld prism was chosen (25 + half of 10),  Held base down and out in front of the nondominant left eye.  The prism was rotated slightly clockwise and counter- clockwise until fusion occurred.  The outside of the glasses were marked with a wax pencil along the base of the prism.  An optician applied a 30-PD Fresnel prism with the base oriented as marked. The prism relieved the diplopia in primary gaze.
  • 65. How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS) CASE TWO: A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula.  Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze.  A 15-PD handheld prism was chosen (10 + half of 8, rounded off to the closest available Fresnel prism power), held base in and up in front of the left eye,  Then rotated in a manner similar to that described above until fusion occurred.  The glasses were marked with a wax pencil.  The patient took the marked glasses to an optician for application of a 15-PD Fresnel prism, base in and up to the left spectacle lens.  The prism corrected the diplopia in primary gaze.
  • 66. Ophthalmic Prism SLAB-OFF PRISM  Patients who have anisometropia may suffer from diplopia or asthenopia when the line of sight does not pass through the optical centers of their spectacles.  This occurs because the displacement induces a net prismatic effect.  In general, most patients are able to use fusional abilities to adapt to the induced horizontal prism.  However, vertical gaze is often quite problematic. For example, a patient who has a refractive error of –3.00 OD and +1.00 OS will have induced prism when looking away from the optical center. If this patient looks 1 cm below the optical centers to read, the induced prismatic power will be 3Δ (1 cm ×3 D) of base-down prism on the right and 1Δ (1 cm ×1 D) of base-up prism on the left, giving a net prismatic effect of 4Δ base down on the right (base up on the left). Cover testing would reveal a 4Δ left hypertropia in the reading position.  There are several options for treating the vertical prismatic effects
  • 67. Ophthalmic Prism MEASURING PRISM IN SPECTACLES  The effective prism power in spectacle lenses is the combination of ground-in prism plus prism induced by displacement of the optical centers. To measure the amount of effective prism in spectacles, ask the patient to fixate on your own eye, then mark the point where line of sight intersects the lens using a felt tip marker. (The line of sight is the line connecting the object of regard with the center of the pupil.) The prism power at this location is the effective prism power. (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patient's pupil.) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port. If no prism is present, the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle. If prism is
  • 68. Ophthalmic Prism WRITING A PRISM PRESCRIPTION  When prescribing prisms, it is important to specify the amount and direction of the prism in addition to the lens or lenses into which the prism should be incorporated. Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens. In our experience, it is best if Fresnel prisms are placed in the office or by a trusted optician; errors in positioning are frequent when the prisms are placed by inexperienced individuals.  Prescriptions requiring prism must be written with special care to avoid errors. It is advisable to communicate directly with the optician for particularly complex prescriptions. For combined vertical and horizontal deviations requiring oblique Fresnel prisms, the axis of the base must be specified using degrees as for astigmatic lenses. However, the astigmatic axis allows for two positions of the base; that is, ‘10Δ base 30°’ could be interpreted as ‘10Δ base up-and-out in the 30° meridian’, oras ‘10Δ base down-and-in
  • 69.  Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) : - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias . - Abnormal head postures. - Nystagmus. • In a patient with a long-standing paresis, what are the considerations when prescribing prism? • In a patient with a recent onset paresis, what are the considerations when prescribing prism? • How do you prescribe prism using Sheard’s criterion? • How do you prescribe prism using Caloroso’s Residual Vergence Demand Criterion?
  • 70. Terminology a. Corrective or Neutralizing Prism: • Goal – To stabilize normal sensory fusion • Prism Action – Neutralizes the demand for controlling fusional vergence b. Relieving Prism: • Goal – To stabilize sensorimotor fusion • Action – Reduces the demand for controlling fusional vergence c. Overcorrective Prism: • Goal – To disrupt anomalous correspondence • Action – Reverses the demand for controlling fusional vergence
  • 71. Terminology d. Inverse Prism for Training or Disruptive Prism Therapy: • Goal – To increase fusional vergence ability • Action – Increases the demand for controlling fusional vergence e. Inverse Prism for Cosmesis: • Goal – To enhance cosmesis of a strabismus when a patient has poor treatment prognosis • Action – Optically displaces the image of the eyes in a direction opposite the strabismus when an observer views the patient. f. Yoked Prism: • Goal – To stabilize bv in non-concomitancy or dampen nystagmus • Action – Directs the eyes into a specific gaze direction g. Sector / Regional Prism: • Goal – To stabilize binocular vision in one or more gaze positions • Action – Reduces the demand for controlling vergence in more than 1 gaze
  • 72. 4. Constant Strabismus  a. Corrective Prisms for Resolvable Strabismus  • Avoid using prism when patient has Anomalous Correspondence, peripheral suppression, amblyopia.  • Must have normal correspondence and normal peripheral sensory fusion  • Monitor for prism adaptation. Can use temporary Fresnel prisms.  • Once normal sensory fusion achieved for 3-6 months (can be less for infants)  - Titrate prism 2-4Δ at a time
  • 73.  3M Press-On™ Optics  AVAILABLE PRISMS and ASPHERIC LENSES PRISMS ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS  Diopter Power Power Power  1.0 􀁕 + .5 -1.0 1.0  2.0 􀁕 +1.0 -2.0 1.5  3.0 􀁕 +1.5 -3.0 2.0  4.0 􀁕 +2.0 -4.0 2.5  5.0 􀁕 +2.5 -5.0 3.0  6.0 􀁕 +3.0 -6.0 4.0  7.0 􀁕 +3.5 -7.0 5.0  8.0 􀁕 +4.0 -8.0 6.0  9.0 􀁕 +5.0 -9.0  10.0 􀁕 +6.0 -10.0  12.0 􀁕 +7.0 -11.0  15.0 􀁕 +8.0 -12.0  20.0 􀁕 +10.0 -13.0  25.0 􀁕 +12.0 -14.0  30.0 􀁕 +14.0  35.0 􀁕 +16.0  40.0 􀁕
  • 74. Conditio n Relevant Issues Function of 3M Press- On prism Suggested use of 3M Press-on Prisms STRABISMUS Early onset strabism s Surgical over and under- correction is a common problem Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically. To obtain presurgical fusion without weight, thickness, and incoveniene of conventional prisms To provide a fusion lock and stability for post-surgical residual deviations.
  • 75. Condition Relevant Issues Function of 3M Press- On prism Suggested use of 3M Press-on Prisms STRABISMUS Mild Amblyopia Requires early intervention to avoid progression Applied over the preferred eye as a weak patch Small image degradation of prism serves as weak occluder Prisms blurs visual acuity in dominant eye
  • 76. Condition Relevant Issues Function of 3M Press- On prism Suggested use of 3M Press-on Prisms STRABISMUS Nystagmus Can allow patient to assume a more normal head position to find the null point of the nystagmus Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn Redirects the visual gaze toward the fireld of minimal tremor Requires placement of prisms over both lenses. In absence of strabismus ,the power needs to be matched.
  • 77. Condition Relevant Issues Function of 3M Press- On prism Suggested use of 3M Press-on Prisms STRABISMUS Inoperable strabismus Fragile health or patient concerns may delay or preclude surgery Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (e.g.,base-in prism for esotropia). For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe Cosmesis
  • 78. Condition Relevant Issues Function of 3M Press- On prism Suggested use of 3M Press-on Prisms DIPLOPIA Associated with several health issues, I.e. including mechanical restrictions, neurologic disorders (nerve palsies), poststroke skew deviation, postretinal detachment,scleral buckles, thyroid ophthamology , injuries such as blowout fractures and brain injuries 3th, 4th , and 6th nerve palsies May recover with time Allows binocularity during recovery period. May be changed as muscle function returnes. To eliminate diplopia resulting from recent- onnset strabismus (e.g.stroke, ocualr muscles paresis systemic disease)
  • 79. Condition Relevant Issues Function of 3M Press- On prism Suggested use of 3M Press-on Prisms DIPLOPIA Associated with several health issues, I.e. including mechanical restrictions, neurologic disorders (nerve palsies), poststroke skew deviation, postretinal detachment,scleral buckles, thyroid ophthamology , injuries such as blowout fractures and brain injuries Incomitant strabismus Deviation varies with gaze direction0 Applied over part of a lens at allow correction in specific gaze positions. For incomitant strabismus, which demands different prism power in certain fields of gaze Prisms can be easily cut and placed on spectacles for correction where needed
  • 80. Condition Relevant Issues Function of 3M Press- On prism Suggested use of 3M Press-on Prisms PHORIAS Symptomatic or Decompensate d phorias Fusion disruption causes eyes to deviate Promotes, fusion reduces deviation For symptomatic phorias with different distance and near angles, apply prism to upper and/or lower portions of spectacle lenses
  • 81. Condition Relevant Issues Function of 3M Press-On prism Suggested use of 3M Press-on Prisms Other Medical Indications for Press-On prisms Bed-ridden patients Cannot elevate head to read or watch television Based-down prisms on both lenses change image’s angle Apply 30* prism base down to each spectacle lenses Ankylosing spondylitis other postural deformities Limited head movement Prisms change image’s angle Apply prism base up to spectacle lens
  • 82. case1  A 45 years- old man who had car accident two week ago came with intractable diplopia .  Vision: 20/20(o.u)  Motility: 40 prism diopter ET with limitation of abduction(-4) in right eye.  Fundus: normal. What is your management
  • 83. case2  15 years old boy referred to strabismus clinic for deviation. He had occasional deviation especially after illness and complain of asthenopia.  BCVA:OU:20/20  Refraction:-0.5sph(OU)  EOM:10 prism diopterX(far),2o prism diopterX (near)  Fundus: normal What is your plan?What is your plan?
  • 84. Other indication  Fourth Nerve Paresis  Accommodative Esotropia  Acquired Esotropia  Intermittent Exotropia  Multiply Operated Strabismus  Thyroid Ophthalmopathy  Nystagmus
  • 85. Sixth Nerve Paralysis  Acute cases of any age or origin are followed without treatment for 3 to 4 weeks  If healing begins within a month it typically will be progressive and complete  After 1 month, if disabling diplopia persists and recovery is not progressing, or if a child remains esotropic in all gaze positions so that binocularity is threatened, then injecting the medial rectus (MR) on the affected side(s) is appropriate
  • 86.  for diabetic patients who have a generally good prognosis, the value of botulinum toxin treatment lies in earlier rehabilitation.  botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery  Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated.
  • 87. Infantile Esotropia  Simultaneous bimedial toxin injection is quite successful  All reports include 2 years or more of follow-up and show high correction rates of 60% to 80% with multiple injections  Perform simultaneous bimedial injection  Inject as early as age 3 months.  Repeats simultaneous bimedial injection with recurrence of esotropia exceeding 15 PD
  • 88. Side effect  Ptosis  Induced vertical deviation  Hemorrhage  Pupillary dilation  Globe perforation
  • 89. orthoptics  Goal is give comfortable binocular vision  used to combat suppression,amblyopia,ARC,enhance fusional amplitude and improve stereopsis  In successful case transform tropia to phoria but not eliminate it  Supervision and direction of treatment responsibility of ophthalmologist
  • 90. Application  Convergence insufficiency  Fusion training  Antisuppression training  ARC
  • 91. Convergence insufficiency  Most effective treatment  Converge on an approaching object such as pencil or a light while red filter is placed over one eye  Aware of physiologic diplopia of a distant object while fixing on a target at near  Training fusional convergence with base out prism or major amblyoscope  Base out prism used during reading and continue on home with increasing power
  • 92. Fusion training  Training of fusion amplitude enable symptomatic heterophoria patient more comfortable  Done by major amblyoscope or prism exercise
  • 93. Antisuppression Training  Orthoptic is aimed to awareness of physiologic diplopia in heterophoria and diplopia in heterotropia  Once diplopia elicited vergence control activated  Forcing suppressed area concurrently with corresponding area of dominant eye  Stimulation of retina of deviated eye by moving visual target on major amblyoscope back and forth across suppression scotoma  Suppression cannot be effectively eliminated by orthoptic
  • 94. ARC  Treatment is no longer practiced  The methods that were used are historical and theoretic  Based on principle that if the image of the fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization  ARC had benefit in preserving advantage of normal binocular vision so do not treat it