What every physician should know about the eye

1. What every physician should know about the eye What every physician should think about vision and the eye Michael B. Gorin, MD PhD Professor of Ophthalmology Jules Stein Eye Institute - UCLA

2. Goals of this talk • What is blindness • Understand basic concepts regarding vision and its assessment • How do we evaluate the eye • Appreciating the diversity of ocular disease • The eye with respect to general health and systemic disease • The “biggies” • What do you do with a patient with possible vision or eye problems.

3. “Non-goals” of this talk • Detailed discussion of ocular anatomy, physiology, biochemistry and genetics • You should have already had this in prior sections • There is a website in your handout to review this material and you will have a quiz on the morning of the first day to ensure that you have the necessary information for the clerkship. • Eye examination skills for the general physician • This was covered in the prior workshop (2nd year)

4. “Non-goals” of this talk • Recognition of the findings of different types of eye disorders • Management and treatment of major or common eye conditions • These are the primary goals of this 3rd year clinical clerkship experience. • Convincing you that ophthalmology is the best specialty in medicine

5. What is blindness? • Blindness is a very indistinct term that has different meanings in different contexts. • A person whose vision is insufficient to carryout normal sighted tasks (ie color blindness, night blindness) • 2) A person whose vision is restricted to 20/200 or worse in their better eye or with reduced central visual fields of less than 20o - Legal definition of blindness • 3) A person with no vision at all (no light perception) - actually relatively rare

6. What is the definition of blindness? 20/10 - 20/25: Normal 20/30 - 20/60: Near-normal 20/70 - 20/160 : Moderate vision impairment - eligible for education assistance in US 20/200 - 20/400: Severe vision impairment - legal blindness in US (visual field < 20 degrees) 20/500 - 20/1000: profound vision impairment - WHO and several European countries definition of blindness (visual field < 10 degrees),CF < 3m < 20/1000: Near-total visual impairment: used by some developing countries as definition of blindness (visual field < 5 degrees),HM, LP NLP: Total visual impairment

7. Causes of Worldwide Blindness • Cataract 17 million • Trachoma 6.0 million • Glaucoma 3.0 million • Xerophthalmia 0.5 million • Onchocerciasis 0.5 million • AMD 1.0 million • Diabetic retinopathy 0.25 million • Leprosy 0.25 million • Others 2.5 million • 85% of blindness is in Africa and Asia • 85% of cases are potentially treatable or preventable • Prevalence: • 0.125-0.25% in Western world • 0.2-1.5% (av 0.75%) in Asia • 0.3-3.1% (av 1.2%) in Africa Allen Foster in Clinical Ophthalmology - Duane, ed. (1991)

8. Aging and Blindness • Prevalence(in Germany) : • 15 % lose sight < 20 years old • 51% lose sight >50 and <80 • 15 % lose sight > 80 years old • Incidence: • 50% of new cases are people over 80 • “Imbalance” due to differences in life expectancy and duration of blindness. • Blind < 10 years - 74% • Blind >10 years - 26% • Blind > 20 years - 10%

9. Vision parameters • Central visual acuity • Contrast sensitivity • Color • Adaptation • Peripheral vision • Binocularity and stereopsis • Central Processing • Confounders - nightblindness, photopsias, photophobia, scotomas, distortions, glare

10. Central visual acuity • Derives from the central 250 microns of the retina • Beyond 250 microns, central acuity declines rapidly • Measured by Snellen chart or ETDRS Note: high contrast, high luminance conditions • Requires proper central (brain) development Early vision impairment can prevent good central vision even if problem is corrected - amblyopia

11. Central visual acuity • • Uncorrected and corrected • • Refractive error • Myopia • Hyperopia • Astigmatism • Presbyopia • • Snellen chart, near card, and the ETDRS chart ETDRS Chart Back-illuminated, High luminance, High contrast

12. Normal View Central loss with paracentral blurring Fixation on head Central loss with paracentral blurring Fixation on paper

13. Contrast sensitivity • Variations in vision with different lighting conditions • Different tests • Pelli Robison, others • Important to consider how different lighting conditions can affect functional acuity

14. Normal contrast Reduced contrast Pelli-Robison Chart

15. Color • Most common vision deficiency other than refractive error. • Most screening tests are for red-green congenital colorblindness • Color deficiencies are also seen in progressive conditions such as cone and cone-rod dystrophies • Testing (CRT, plates and chips)

16. Ishihara Color plates Left - Normal Right - Red green deficiency

17. 1: Normal 2: Red-green 3: Complete color deficiency 1 3 2 Farnsworth D-85 Color Testing

18. Adaptation • Adjustment to lighting changes • Nightblindness (such as with RP, Diabetics) • Delayed recovery from photostress test • (macular dystrophies, some stationary conditions (fundus albipunctatus) • Goldman Weekers adaptometer, qualitative macular stress test • Not routinely tested

19. Goldman Weekers Adaptometer Central panel: poor light adaptation, nightblindness

20. Peripheral vision • Tested with visual fields • Abnormal in RP, glaucoma as well as other conditions • When loss is gradual, patients adapt very well until advanced disease • Important to understand how the brain builds a picture of the world. • A constricted visual field is like painting a large wall with a small brush. It takes more time and effort. Harder for a person to perceive a sudden change.

21. Automated Perimetry Visual Field Test Normal Glaucoma

22. Web site to play with simulations of vision loss for different conditions glaucoma, macular degeneration, cataracts, retinitis pigmentosa, diabetic retinopathy, myopia, astigmatism, hyperopia http://my-vision-simulator.com/ Fun to use Not very accurate Only shows limited aspects of vision loss

23. Binocularity and Stereopsis - 1 • Binocularity refers to the use of both eyes to obtain a merged view of the world. • One can have binocular vision without stereopsis. • Stereopsis is the perception of depth based upon image disparities perceived by the brain from the input from both eyes. • One cannot have stereopsis without binocular vision. • One can have binocular vision without stereopsis.

24. Binocularity and Stereopsis - 2 • Depth perception is the awareness that objects are closer or farther from the subject and the position of objects with respect to each other. • One can have depth perception without stereopsis. • Often lost in strabismus and amblyopia • May be diminished with poor central vision • Can be lost over time if person loses too much vision to allow for fusion • Generally not critical to distance perception. • Not essential for driving and most tasks • Testing is done with polarizing glasses or special examination devices.

25. Central processing • Cognitive perception of vision • Usually not tested by ophthalmologists • Seen with dyslexias, vision-deprivation amblyopias • May be evident as problems with certain tasks such as reading or recognition of images • Can be abnormal in patients with dementias who claim that they can’t read but have “20/20” acuities

26. Confounders of vision • Distortion • May affect acuity or the ability to have stereopsis • Photophobia • Perception of pain under normal lighting conditions • Seen in a variety of conditions, especially cone dystrophies and albinism. • Can be disabling for some people • Glare • Certain cataract and corneal opacities will scatter light, creating distracting images

27. Confounders of vision • Photopsias - flashing lights • May be a minor symptom but can vary and be very troublesome in some individuals. • Can occasionally worsen with stress or fatigue • Different patterns for retinal degenerations as compared to migraines • Blind infants will often press on their eyes to trigger photopsias to provide stimulation to the visual pathways. • Charles Bonnett phenomenon • visual hallucinations in people with acquired blindness

28. Each visually-impaired child or adult, regardless of their condition, has a unique set of vision challenges • Even if a condition predominantly affects a particular aspect of sight, one must appreciate individual variation in other components. • Vision loss in an infant is not the same in an older individual, even if central acuities are the same. • The rate of vision loss has a major impact on a person’s ability to modify their vision-based behavior. A child with Stargardt disease and loss of central vision is not the same as an elderly individual with age-related macular degeneration.

29. Evaluating the eye - 1 • Symptoms • pain, itching, light sensitivity (photophobia) • Function • changes in visual function • blurring, peripheral loss, distortions, flashing lights, afferent pupillary defect, eye movements • Appearance • redness, distension/swelling of tissues, clouding of the cornea or lens, loss of red reflex, lid ptosis, assymetry between the eyes, optic nerve changes

30. Evaluating the eye - 2 • Diagnostics • Functional • Acuity (pinhole, refraction) • Visual fields (confrontation, quantitative) • Color tests (red desaturation, screening, quantitative) • Structural/Anatomic • Slit lamp, fundus imaging • Angiography (Fluorescein/ ICG) • Optical coherence tomography (OCT) • Ultrasonography • Electrophysiologic • VEP, ERG, mfERG, EOG

31. The Eye as a microcosm of the rest of health (systemic examples and ocular examples not exact counterparts) Infection URI Conjunctivitis sepsis Endophthalmitis, Orbital cellulitis Malignancy Lung Ca Melanoma Pediatric leukemia Retinoblastoma Immunology Asthma Allergic conjunctivitis Lupus Uveitis, Scleritis Genetic Muscular dystrophy Retinitis pigmentosa Aging BPH Cataract Atherosclerosis Macular Degeneration Vascular disease CAD/Stroke Transient Ischemic Attacks Vein or Arteriolar occlusions Pulmonary embolus Retinal artery embolus

32. The Eye as a microcosm of the rest of health (systemic examples and ocular examples not exact counterparts) Neurologic Dementia Retinal degeneration Optic atrophy Neuromuscular Strabismus Migraines Visual migraines Trauma UV Skin damage Ptyergium Post CA reconstruction Lid reconstruction after cancer resection Abnormal growth GH deficiency or excess hyperopia or myopia Toxic (acute versus chronic) Lead poisoning Ferrous toxicity Digoxin Plaquinil retinopathy Ethambutol optic neuropathy Loss of homeostasis Hypertension Glaucoma

33. The Eye as a portal of general health what we can see (when we know how to look) • • HTN, vascular disease, arrhythmias • • Diabetes • • Metabolic disorders • • Genetic syndromes (VHL, NF, myotonic dystrophy, lysosomal storage diseases) • • Autoimmune conditions • • Infection (emboli to the eye, bacterial, fungal, viral) • • Cancer (metastatic disease) • • Neurologic – papilledema, migraines, abnormal eye movements

34. What are the “biggies” • Infants: • Amblyopia • Strabismus • Loss of the red reflex • Children and Young adults: • Refractive error • Infections • Trauma • Inherited disorders • Older adults: • Cataract, Glaucoma, Diabetic Retinopathy, • Macular Degeneration, Vascular disease

35. What do you need to know when presented with an “eye” patient (or any patient) • Is this person’s visual function normal? • If not, can it be accounted for by my knowledge of prior conditions (including refractive error)? • Does this person have new or recent symptoms that may be eye-related? – e.g. pain, blurred vision, flashing lights • Based on my examination skills – can I confidently establish what features are normal and what are not. • Are the symptoms and findings serious? Do they require urgent attention?

36. Who should care for my patient’s eye and/or vision problems Opticiansfit glasses (they do not provide the prescription for the lenses, they do fitting) Optometristscan handle glasses and contact lenses, can make basic diagnoses and are legally allowed to prescribe eye medications. Training is 4 years after college. A small percentage do postgraduate training. The majority of their clinical training exposure is to normal people. Ophthalmologistsare physicians and complete 4 years of medical school an internship and three-year residency. They are trained in both medical and surgical care. The majority of their training exposure is to patients with significant eye pathology. Many of them do 1-2 year subspecialty fellowships: pediatric ophth., neuro-ophth., medical retina, vitreo-retinal surgery (including medical retina), oculoplastics, glaucoma, cornea and external disease, refractive, ocular oncology, ocular immunology.