This is about, How the assess and manage the low vision patients

1. Low vision management
Mahendra Singh
M.optom. FLVPEI
Consultant Optometrist - (low vision services)
C.L Gupta eye institute, Ramganga Vihar, Phase-II, (Extn.)
Moradabad 244001 (India)
Ph.: +0591-247700/801 Mob: +91 6395586269 Email:
lva@clgei.org
Website: www.clgei.org

2. Classification of Vision Loss

3. 1.Overall blurred vision
2.Centeral field loss
3.Peripheral field loss
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Categories of Vision loss

4. Normal vision

5. 1.Overall blurred vision
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6. 2.Central field loss
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7. Peripheral field loss
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8. Objective
• Definition: VA<6/18, VF <10 degree,
• Who / How to start low vision clinic
• Elements of low vision examination
• Clinical examination
• Final Glasses prescription low vision patients
• Case management (Overall, central & peripheral blurred
vision)
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9. ?can (LVA)
• Optometrist.
• Ophthalmologist.
• Low vision therapist
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10. Services can be provided
• Hospital
• Vision Rehabilitation Organization.
• Private optometry and Ophthalmologist Practice
• Educational Institute
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11. Elements of low vision examination
1. Review of medical records
2. Observation
3. Assessment of functional needs
4. Assessment of capabilities and limitation of the
visual system.(Vn & Ref)
5. Calculation of magnification
6. Trail of low vision devices
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12. Clinical Examinations
1. Visual acuity
2. Refraction
3. Contrast sensitivity (CS)
4. Glare testing
5. Color vision
6. Visual fields

13. Refraction
• Usually overlooked/neglected
• Prevailingmyths
– Ocular pathology only causeof low vision/poor
functioning
– VA improvementto alevel
<6/60 (or <20/200) is considered
insignificant
– Should be corrected

14. RefractionSpecialConsideration
Objective Refraction
• Large FixationTarget
• Adjustabletrialframeand
wide aperture loose lenses
• Techniques
– Radical retinoscopy
– Over-refraction
SubjectiveRefraction
• Non-standard test dist.
• Determine Just
Noticeable Difference
(JND)
• BracketingTechnique

15. Concept ofJND
• JND = Denominatorof presentingVA /30 (inm)
or VA /100 (in f)
• Example (i)
Unaided VA6/60 for 20/200
JND = 60/30 = 2D = 200/100 = 2D
• Example (ii)
Unaided VA6/360 for 20/1200
JND = 360/30 = 12D = 1200/100 = 12D

16. GlareTesting
• Practical
– Squeezingof lids
– Bending head
– Using handas visor
– Mobility
• Comfort
• Speed
• Any use oftactile clue
• Bumpinginto objects
• Brightchartshouldbeusefor
checkingVA

17. Refraction.
Providing Magnification.
Glare Control
Increase Contrast
Rehabilitation services
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Management of Overall blurred vision

18. • Refraction
• Magnification
• Glare control
• Increase contrast
• Eccentric viewing techniques
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Central Field loss

19. Eccentric viewing technique.
• Eccentric viewing: This require development of new
preferred retinal locus (PRL) that can be use at the
“new fovea”
• Teaching awareness of the scotoma.
• Teaching off foveal viewing.
• Moving reading material instead of moving head.
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20. Peripheral field loss
1. Refraction :- should be accurate
2. Magnification
3. Increase contrast
4. Training in orientation and mobility.
2.Magnification :- In advanced peripheral field loss there is poor response to higher
magnification because increase magnification visual field decrease further. Sometime only lower
magnification is suitable for patients with peripheral field loss.
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Peripheral field loss

21. • 3.Increase contrast: Non optical devices
:Environmental modification
• 4.Training in orientation and mobility: A person with peripheral
field loss will have more difficulty in orientations and mobility as compared to other two
categories of vision loss. Varies type of devices and training can improve his independent
orientation and mobility.
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22. Anterior segment
Cornel opacity
1. Problem causes a over all blur and an artificial pupil
contact lens will be more helpful.
2. The opacities causes scattering of light.
3. Can controlled by filters,
4. Especially orange colored filters
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23. Corneal Dystrophies
• Pinhole spectacle lenses.
• Aaperture control contact lenses.
• Non optical system as large print.
• Bold line notes.
• Typoscopes.
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24. Aniridia
• Pupillary aperture control contact lenses with Iris
colour tint.
• Its work in
• Reduce photophobia.
• Improve visual acuity
• Reduce nystagmus.
• For photo phobic complaints direct illumination,
filters and sunglasses are beneficial.
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25. Dislocated lens
• Correction of aphakic eye with spectacle or contact
lens will be the first option.
• If no surgical option is feasible like a one eyed patient
or with coloboma where a detachment is possible.
• Diplopia can be eliminated by pinhole lenses.
• Stenopic slits or aperture control contact lenses.
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26. Posterior segment
Retinitis Pigmentosa
• Most challenging experience.
• Managing an RP patient with constricted fields.
• Field expanders
• The field of vision can be expanded only by
magnification of target with a reverse Galilean
telescope
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27. • Patients who travel at night alone are advised to use
search lights.
• For these patients light is a medicine at dark.
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28. Coloboma
• Aperture control contact lenses or painted iris contact
lens helps.
• There is a superior field loss by posterior coloboma.
• Patients are instructed about field loss due to superior
coloboma and explained how to navigate indoors.
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29. Diabetic Retinopathy
• Eccentric viewing, (M).
• Electronic aids such as CCTVs can be of help in
magnification in patients less than 3/60 vision.
• Non optical devices such as glucose blood sugar
monitor and insulin syringe aids.
• It is better to use binocular lens than monocular lens.
• A flip in or a clip on brown or orange filters with side
shields should be used to avoid a glare
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30. Macular Degeneration
• Before giving a low vision trial the amsler grid test is
important in assesing the extent of scotoma.
• Prismospheres are suitable which shifts the macula
scotoma.
• High level of illumination above 1000 lux.
• Increased direct illumination should be recommended
for all near tasks,
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31. Myopic degeneraion
• Contact lens serve as a better low vision aids in high
myopia.
• In myopia spectacle lens produce minification of
images.
• The contact lenses serves as an advantage over
spectacle lens of same power.
• Contact lens eliminates the peripheral distortions and
prismatic effects.
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32. Cont..
• In spectacle :
• Small round frame.
• High index lens with antireflective coating.
• For refractive errors more than -15.0 dioptres a
myo disc lens can be used.
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33. Achromatopsia (partial or total absence of color vision)
• These patients function better in an environment with
reduced illumination.
• Red tinted contact lenses and red sun lenses used to
decrease photophobia.
• Side shields on spectacle frame.
• Hats with large brim is helpful outdoors.
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36. Albinism
• Albinotic patients are ideal candidates for magnification
due to absence of central or peripheral field defects.
• Refractive errors correction as it improves vision and
reduce nystagmus.
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37. Albinism
• Soft cosmetic, contact lens.
• Majority of the albinotic patients will be benefited by
the photochromatic tinted glasses like the A2 crooks
• A cap to avoid sunlight should be insisted.
• For the achromatopias red on orange tinted lenses.
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Contact me on lva@clgei.org
Contact number:- 6395586269
3 Months low vision training program.
Thank you