Low vision rehabilitation in patients with retinal dystrophy
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Low vision rehabilitation in patients with retinal dystrophy

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The presentation I have made and uploaded provides you with an in-depth insight into the rehabilitation of patients with retinal dystrophy on the part of LOW VSION. It also details the features the ...

The presentation I have made and uploaded provides you with an in-depth insight into the rehabilitation of patients with retinal dystrophy on the part of LOW VSION. It also details the features the patients present with and specific tests that are launched.
The author does not assume responsibility or legal liability for any errors in the text or for the misuse or misapplication of material in this work.
No copyright infringement, or plagiarism intended.
Amrit Pokharel

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Low vision rehabilitation in patients with retinal dystrophy Low vision rehabilitation in patients with retinal dystrophy Presentation Transcript

  • Amrit Pokharel
  • Dystrophy?? A hereditary, symmetrical, congenital or later appearing, slowly progressive affection, presenting slight intrafamilial variation, and of unknown etiology.
  • Dystrophy?? It was suggested that conditions secondary to systemic factors should not be considered dystrophies, but the authors find it somewhat artificial to exclude entities with systemic manifestations from the definition. Retinitis Pigmentosa has been found to be associated with systemic conditions that are inherited and is called one of the retinal dystrophies
  • Retinal Dystrophies Generalised photoreceptor dystrophies  Typical retinitis pigmentosa  Atypical retinitis pigmentosa  Progressive cone atrophy  Leber Congenital Amaurosis  Stargardts disease and Fundus flavimaculatus  Bietti corneoretinal crystalline dystrophy  Alport syndrome
  • Retinal Dystrophies Generalised photoreceptor dystrophies  Familial benign fleck retina  Pigmentary paravenous chorioretinal atrophy  Congenital stationary night blindness  Congenital monochromatism
  • Retinal Dystrophies Macular Dystrophies  Juvenile Best macular dystrophy  Multifocal Vitelliform lesions without Best disease  Pattern dystrophy  North Carolina macular dystrophy  Familial dominant drusen  Sorsby pseudoinflammatory dystrophy
  • Retinal Dystrophies Macular Dystrophies  Benign concentric annular macular dystrophy  Central areolar choroidal dystrophy  Dominant cystoid macular oedema  Sjogrens-Larsson syndrome  Familial internal limiting membrane dystrophy
  • Goals Identify patients with visual impairment(s) who might benefit from low vision care and rehabilitation Evaluate visual functioning of a compromised visual system effectively Emphasize the need for comprehensive assessment of patients with impaired vision and referral to, and interaction with, other appropriate professionals
  • Goals Maintain and improve the quality of eye and vision care rendered to visually impaired patients Inform and educate other health care practitioners and the lay public regarding the availability of vision rehabilitation services
  • Goals Increase access for the evaluation and rehabilitative care of individuals with visual impairment(s), thereby improving their quality of life.
  •  Vision rehabilitation As defined by the American Optometric Association the process of treatment and education that helps individuals who are visually disabled attain maximum function, a sense of well being, a personally satisfying level of independence,
  •  and treatment including, but not limited to, the prescription of optical, non-optical, electronic and/or other treatments. The rehabilitation process includes the development of an individual rehabilitation plan specifying clinical therapy and/or instruction in
  • Quantifiers of Visual Impairment The ICD 10-ICIDH has employed the following quantifiers:  Visual Acuity  Visual Field  Contrast Sensitivity
  • Quantifiers of Visual Impairment The approach is to use functional terms to classify the type of Visual Field defect. This approach is a useful way to think of problems the patient may encounter:
  • Quantifiers of Visual Impairment …the patient may encounter:  Novisual field defect, but a loss of resolution or contrast throughout the entire visual field; general haze or glare  Central visual field defect  Peripheral visual field defect
  •  For rehabilitation work, must know thing:  Visualfield defect loss of contrast and resolution  Central VF defect  Peripheral VF defect
  •  For the Guideline here on how to rehabilitate the patients with retinal dystrophy, Low vision instruction, low vision training, low vision therapy, vision rehabilitation theapy and vision rehabiliatation training are synonymous
  • CARE PROCESS Diagnosis of Low Vision  PatientHistory  Ocular Examination  Visual Acuity  Monitor stability or progression of disease  Assess eccentric viewing postures and skills  Assess scanning ability( for patients with restricted field)  Assess patient motivation  Teach basic concepts and skills( ie to eccentrically view) relevant to rehabilitation process
  • CARE PROCESS Diagnosis of Low Vision  PatientHistory  Ocular Examination  Refraction  Use of JND technique  Radical retinoscopy
  • CARE PROCESS Diagnosis of Low Vision  PatientHistory  Ocular Examination  Ocular motility and Binocular Vision Assessment  Evaluate for the presence of nystagmus, ocular motility dysfunction( eg poor saccades and pursuits)  Look for strabismus, substandard binocularity, or diplopia
  • CARE PROCESS Diagnosis of Low Vision  PatientHistory  Ocular Examination  Ocular motility and Binocular Vision Assessment  Gross assessment of ocular alignment( eg Hirschberg estimation)  Sensorimotor testing( Worth four dot test, red lens test)  Amsler grid test, monocularly versus binocularly to determine eye dominance and the possible need for occlusion
  • CARE PROCESS Diagnosis of Low Vision  PatientHistory  Ocular Examination  Ocular motility and Binocular Vision Assessment  Contrast sensitivity , monocularly versus binocularly to determine eye dominance and the possible need for occlusion  Effect of lenses, prisms, or occlusion on visual functioning
  • CARE PROCESS Diagnosis of Low Vision  PatientHistory  Ocular Examination  Visual Field Assessment  Central vs Peripheral VF defects  Confrontation VF testing  Amsler or threshold Amsler grid assessment  Automated static perimetry  Tangent screening  Goldmann Bowl perimetry or equivalent kinetic testing
  • CARE PROCESS Diagnosis of Low Vision  PatientHistory  Ocular Examination  Ocular Health Assessment  External examination( adnexa, lids, conjunctiva, iris, lens, and pupillary response)  Biomicroscopy( lids, lashes, conjunctiva, tear film, cornea, anterior chamber, iris, and lenses)  Tonometry  Central and peripheral fundus examination with dilation unless containdicated Dilation not to be carried out prior to working with lenses
  • CARE PROCESS Diagnosis of Low Vision  PatientHistory  Ocular Examination  Supplemental Testing  Contrast sensitivity testing  Glare testing  Visually Evoked Potentials (VEP)  Electroretinogram( ERG)  Electrooculogram( EOG)  Colour Vision testing
  • CARE PROCESSManagement (Low visionrehabilitation)
  • Rehabilitation The goals discussed earlier are met by;  Improving distance, intermediate, or near vision  Improving print reading ability  Reducing photophobia and/or light-to-dark or dark-to-light adaptation time
  • Rehabilitation The goals discussed earlier are met by;  Improving the ability to travel independently  Improving the ability to perform activities of daily living  Maintaining independence  Understanding the diagnosed vision condition, prognosis,and implications for visual functions
  • How to start?? An optometrist should individualize the management plan for each patient while planning a course of therapy.
  • How to start?? An optometrist should CONSIDER the following:  Degree of VI  Underlying cause( here retinal dystrophy)  Patient‟s age and developmental level
  • How to start?? An optometrist should CONSIDER the following:  Overall health status of the patient  Patient‟s adjustment to visual loss
  • How to start?? An optometrist should CONSIDER the following:  Patient‟s expectations and motivations  Patient‟s(cognitive) ability to participate in the rehab  Lens systems and technology available
  • Rehabilitation process Use of devices:  Optical Devices  Non-Optical Devices  RGPHOMeS
  • Looking at the statistics… 40 35 30 25 20 40 15 10 5 10 10 10 10 5 5 5 3 2 0
  • `Presenting complaint Possible rehabilitation optionsDifficulty in reading Refraction, lighting, high reading add spectacles, hand held magnifiers, CCTV, large prints/talking booksDifficulty in recognizing faces Refraction, fixation advice/training, lightningDifficulty in watching TV Refraction, Changing Viewing distance, Fixation advice /training telescopic magnifiersDifficulty in navigation/mobility Orientation and mobility training, Refraction, Telescopic magnifiers (for street signs)
  • `Presenting complaint Possible rehabilitation optionsDifficulty in using computer screens Text enlargement software, Screen reading software, RefractionDifficulty in kitchen/household tasks Lighting, Contrast advice, Hand magnifiersDifficulty in shopping Hand magnifiers, Portable lightning, Handheld CCTVsDifficulty in hobbies Refraction, Galilean Telescopes, Text(reading, music, gardening, painting) enlargement
  • Eccentric viewing
  •  Eccentric Viewing Eccentric viewing refers to the technique of  observing a scene with the peripheral retina, by moving the damaged fovea away from the object of interest
  •  Eccentric Viewing Due to the lower density of photoreceptors and greater number of photoreceptors per ganglion cell in the peripheral retina,  visual acuity will be far worse as that in the fovea.  This strategy can, however, provide an unobstructed view of the scene
  • Retinitis PigmentosaUsher SyndromeHallgren‟s SyndromeRefsum‟s syndrome
  •  Prognosis: worst prognosis severe Vision loss by 4th  XL- decade  ARor sporadic cases-favourable with retention of CF until 5th decade  ADbest prognosis and CF present beyond 5th decade
  •  ERG in RP  Decreased in fERG  Early pERG may be normal,Later gets abnormal  Amplitude reduction in the periphery that corresponds to VF defect
  • CHARACTERISTICS OFDISEASES Dark Line in Retina Decreased Night Vision Loss of Peripheral/Central Vision Decrease in Visual Acuity
  • Functional Implications Peripheral vision lost Limited visual field Limited mobility Debilitating glare Extreme sensitivity of light Eventual Blindness
  • Rehabilitation Wearing glasses Low vision devices Magnification and illumination of objects
  • Rehabilitation Field enhancers are employed since visual field is markedly constricted.
  • Rehabilitation So how is peripheral VF defect management launched?
  • Rehabilitation Consider the goals as given by the AOA and work under the following five areas:  Maximized VA  Glare and photophobia control  Magnification  Field enhancement techniques  Referrals for additional services
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Maximized VA Visual Acuity  VA testing at appropriate distance so as not to overwhelm the field with the letter size RP patients have difficulty seeing a larger object at near
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Maximized VA Visual Acuity Proper illumination( towards a brighter side) depending on other ocular associations, Cataracts, for example
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Maximized VA Refraction Allow for eccentric viewing(EV) Encourage the EV if the px achieves better VA
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Maximized VA Binocularity The asymmetric nature of RP makes it difficult for pxs to maintain healthy fusion because of differences in the acuity( > 2 lines)
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Maximized VA Binocularity Also the frequent association of nystagmus supports the binocularity, for monocularity seems to worsen nystagmus.
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Glare and photophobia control Glare and photophobic sensitivities ??? Reduced contrast sensitivity, slower responses to dark adaptation and secondary media defects…
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Glare and photophobia control Glare and photophobic sensitivities ??? The RPE tends to absorb less light hence supports light scattering. Glare interferes with the middle and
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Glare and photophobia control Use of various lenses like Corning, NoIR. These absorb wavelengths towards blue that are responsible for more
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Glare and photophobia control Corning Lenses CPF 550(Amber) esp for RP NoIR filters 4% Dark Plum 2% Medium Plum
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Glare and photophobia control Corning Lenses CPF 550(Amber) esp for RP NoIR filters 65% Yellow 49% Red
  • Glare and Contrast
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Glare and photophobia control Peaked caps Tinted screen CCTVs Also use of typoscopes
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Glare and photophobia control Illumination Incandescent lamps( 75-100)
  • Rehabilitation
  • Adequate light ( natural / lamp) for daily tasks
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Glare and photophobia control Place the lighting source behind the px So as to do away with the possible unwanted glare Place it to the side of the
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Magnification  In peripheral field defects like in RP, the minimal magnification to be provided coz the stimulation of the peripheral retinal may be of little or no value.
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Magnification Use of microscopes in later stages Also handheld magnifiers, stand magnifiers
  • Stand magnifiers
  • Hand Held Magnifiers
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Visual Field RP shows a cone shaped visual field. Cone shaped?? The patient will show a geometrically expanded field with increased testing
  • Cone shaped VF in RP
  • Rehabilitation Consider the goals as given by the AOO and work under the following five areas: Visual Field Enhancers Prism Minus lens Mirror Reverse Telescope
  • Prism E.g.. Fresnel prism
  • Interpretation When peripheral vision loss is severe (leaving central visual fields of less than 20°), mobility can be reduced. Clinical rehabilitation options in dealing with tunnel vision using nonprismatic methods are limited and have had variable success
  • Interpretation Fresnel prisms may not cause the same central visual field degradation and have added advantages of cosmetic appeal, relative availability, and ease of fitting The rationale for using prisms for field expansion involves increasing scanning effectiveness for patients, resulting in improved peripheral awareness.
  • Interpretation We constantly scan our environment using low spatial-frequency visual channels as we also intermittently spot and view points of interest in visual fields scanned, using various high spatial-frequency visual channels. Cortical temporal multiplexing processes create visual perception as we know it by using the information obtained from scanning and spotting.
  • Interpretation In the presence of tunnel vision, prisms project peripheral fields information otherwise unavailable, thereby enhancing the scanning abilities of the eye. Enhanced scanning ability will produce new spotting eye movements and together both visual skills in fact expand peripheral field awareness.
  • Mirrors
  • Minus lens
  • Reverse Telescope system
  • Amorphic lens
  • Also contrast sensitivity…
  • Also contrast sensitivity… Contrast in Kitchen
  • Environmental Painted edges of Staircasemodification
  • O and M management
  • O and M management
  • Sensory- substitution devices
  • Other Non-optical Devices
  • Progressive Cone dystrophyInheritance Sporadic, AD or XLPresentation 2nd -4th decade with central Vf , CV impairmentSigns …ERG Photopic response- abnormalDA Cone segment abnormalCV Deuteran-tritan defectPrognosis Poor with eventual loss of CV to the level of 6/60
  •  dfnjks
  • Stargardt macular dystrophyInheritance Sporadic, ARPresentation 1st -2nd decade with central VF , malingering??Signs …ERG Photopic response- abnormalDA Cone segment abnormalCV Red-green defectPrognosis Poor with eventual loss of CV to the level of 6/60
  • Characteristics…
  • Characteristics… Poor Colour Vision
  • Tests to be carried out…
  • Management Few guidelines,  When scotoma is located right to the macula, reading becomes difficult as the previous word disappears—leading to difficulty in tracking  When scotoma is located left to the macula, reading becomes difficult as a new word is readily invisible owing to a scotoma. So one should use finger or marker to overcome problem
  • Management Refraction Magnification Non-optical devices Lighting and glare control Eccentric Viewing Prism therapy Text Enhancement
  • Management Eccentric Viewing  To extrafoveate an object of regard
  • Management …EV Discussion:  Besides reducing reading speed, the central scotoma interferes with other visual functions including  Space perception  Contrast sensitivity,  Stereopsis  Fixation stability  Contraindicated when some form of foveal function exists
  • Management …EV Discussion:  After EV training, reading speed doubled with little to no improvement in Visual Acuity.  Reading speed is a better parameter than visual acuity when reporting results of visual rehabilitation because  Reading is more demanding than identifying a few optotypes on a visual acuity chart A practicable approach to rehabilitating patients with CF loss
  • Management Prism Therapy
  • Management Text Enhancement…
  • Management…TextEnhancement Conclusion  Boosting the contrast increases the perceptibility of letters and therefore words, then reading gets faster  Increasing the size of character overcomes the scotomatous region thus allowing the non- macular area to fixate extrafoveally  Increasing the luminance of the characters allows for a better recognition.
  • Psychological/Psychosocialproblems in Retinal Dystrophy Fear of growing blind Fear of ostracism Impaired social life Susceptibility to harassment
  • Refer TrainTreat Low Vision Service Eye Care Education Detect Educate Identification VI Child
  • References:  Tasca Jennifer, Edward A. Deglin. Chapter SIX „Common Disorders Encountered in Low Vision‟ in “ESSENTIALS of LOW VISION PRACTICE”, 1ST Edition, BUTTERWORTH HEIMAN,1999  Kathleen Fraser Freeman, Cole Roy Gordon, Eleanor E Faye, Paul B. Freeman, Gregory L. Goodrich, Joan A. Stelmack. Optometric Clinical Practice Guideline Care of the Patient with Visual Rehabilitation(Low Vision
  • References: Ferraro, J. and Jose, R. T. (1983). Training programs for individuals with restricted fields. In R.T. Jose (Ed.), Understanding Low Vision, American Foundation for the Blind, NewYork. Vol. 14, 363-376. Crossland, Michael D. Visual rehabilitation of patients with macular diseases, in Focus, The Royal College of Ophthalmologists
  • References: Ajit Kumar Thakur, Purushottam Joshi, Himal Kandel, Subash Bhatta.Profile of low vision clinics in eastern region of Nepal: A retrospective study.British Journal of Visual Impairment 2011 29:215 Elisabeth M. Fine, Eli Peli.Enhancement of text for the Visually impaired.J. Opt. Soc. Am. A 1995;12;1439-1447
  • References: Jae Hoon Jeong, Nam Ju Moon. A Study of Eccentric Viewing for Low Vision Rehabilitation. Korean J Ophthalmol 2011;25(6):409-416 Berson EL, Mehaffey L III, Rabin AR. A night vision device as an aid for patients with retinitis pigmentosa. Arch Ophthalmol 1973;90:112–6.
  • References: William H. Ridder III, John B. Slegfried.Chapter 16 „Clinical Electrophysiology‟ in Borish‟s Clinical Refraction, 2nd Edition, BUTTERWORTH HEIMAN Elsevier,2006
  • AND YOU THINK YOU ARE HAVING A BAD DAY AT WORK !!Although this looks like a picture taken from a Hollywood movie, it is in fact a realphoto, taken near the South African coast during a military exercise by the British Navy.It has been nominated by Geo as "THE photo of the year".