• My Dashboard My Education Find an Ophthalmologist
  • Home
  • Coronavirus
  • For Ophthalmologists
    • Meetings
      • AAO 2022
        • Meeting Information
          • Past and Future Meetings
          • Mobile Meeting Guide
          • Contact Information
          • Annual Meeting News
          • Health and Safety
          • Policies and Disclaimers
        • Program
          • Program Highlights
          • Subspecialty Day
          • Virtual Meeting
          • Program Committees
          • CME
          • Meeting Archives
        • Expo
        • Registration
        • Hotels & Travel
          • Hotel Reservation Information
          • Chicago
          • International Attendees
          • Hotel Meeting Space
        • Presenter Central
          • Presenter Central
          • Abstract Selection Process
          • Submission Policies
          • Subject Classification/Topics
          • Instruction Courses and Skills Transfer Labs
          • Papers and Posters
          • Videos
          • Grand Rounds Symposium
          • Program Participant and Faculty Guidelines
          • Faculty Development Program
        • Exhibitors
          • Exhibitor Central
          • Exhibitor Portal Information
          • Exhibitor Prospectus
          • New Exhibiting Companies
          • Exhibitor Resources
          • International Exhibitors
          • Promotional Opportunities
          • Exhibitor Hotel Reservations
      • Mid-Year Forum
        • Registration and Travel
        • Congressional Advocacy Day
        • Advocacy Ambassador Program
        • Program
        • Schedule
        • Sponsored Attendees
        • News
      • Codequest
        • Codequest Instructors
        • Claim Codequest CME or CEU Credit
      • Eyecelerator
    • Clinical Education
      • COVID-19
      • Education
        • Browse All Education
        • Courses
        • Cases
        • Learning Plans
        • Interactive
        • Focal Points
        • Wills Eye Manual
        • Disease Reviews
        • Clinical Webinars
        • Diagnose This
        • Self-Assessments
        • Educational Centers
          • Glaucoma Education Center
          • Pediatric Ophthalmology Education Center
          • Laser Surgery Education Center
          • Myopia Resources
          • Oculofacial Plastic Surgery Center
          • Redmond Ethics Center
      • Journals
      • Guidelines
        • Browse All Practice Guidelines
        • Preferred Practice Patterns
        • Clinical Statements
        • Compendium Guidelines
        • Complementary Therapy Assessments
        • Medical Information Technology
        • Ophthalmic Technology Assessments
        • Patient Safety Statements
        • Choosing Wisely
        • Low Vision
        • Eye Care for Older Adults
        • Eye Disease Statistics
        • About the Hoskins Center
      • Video and Image Library
        • Browse All Videos
        • Clinical and Surgical Videos
        • Presentations and Lectures
        • 1-Minute Videos
        • Master Class Videos
        • Basic Skills Videos
        • Interviews
        • Images
        • Submit an Image
        • Submit a Video
      • Podcasts
        • Browse All Audio and Podcasts
        • Experts InSight
        • Ophthalmology Journal
      • News
        • Browse All Clinical News
        • Editors' Choice
        • Headlines
        • Current Insight
      • CME Central
        • Browse All CME Activities
        • Claim CME Credit and View Transcript
        • CME Planning Resources
        • Complete Your Financial Disclosure
        • Joint Sponsorship Portal
        • LEO Continuing Education Recognition Award
        • Safe ER/LA Opioid Prescribing
        • Check Your Industry Payment Records
      • MOC
      • Resident Education
        • Resident Education Home
        • Browse All Resident Content
          • Courses
          • Flashcards
          • Interactive Cases and Simulations
          • Videos
          • Webinars
        • OKAP and Board Exam Resources
          • OKAP Exam
          • Board Prep Resources
          • OKAP and Board Review Presentations
          • Study Flashcards
        • Cataract Master
        • Diversity and Inclusion Education
        • News and Advice from YO Info
        • Pediatric Ophthalmology Education Center
        • PGY-1 and PGY-2 Resources
        • Simulation in Resident Education
    • Membership
      • Join
      • Renew
      • Current Member
      • Volunteer
      • Physician Wellness
      • Member Directory
      • Member Obituaries
      • AAOE Membership
    • Advocacy
      • Advocacy News
      • Get Involved
        • Ways to Give
        • How to Get Involved
        • Congressional Advocacy
        • Support the Academy's Agenda
        • Research Legislation
        • Find Your Legislators
        • I Am an Advocate
        • Advocacy at Home
        • Advocate Tools
        • Best Practices for Advocating at Home
        • Social Media Toolkit
        • Letter to Editor
        • Town Hall Guide
        • Guide to Engaging With New Lawmakers
        • Resources
        • Attending a Political Fundraiser
      • OPHTHPAC
        • About Us
        • Join OPHTHPAC
        • OPHTHPAC Blog
      • Surgical Scope Fund
        • Support Surgery By Surgeons
        • Surgery By Surgeons Blog
    • Publications
      • EyeNet Magazine
        • Latest Issue
        • Archive
        • Subscribe
        • Advertise
        • Write For Us
        • Corporate Lunches
        • Contact
        • MIPS 2022
      • Focal Points
      • Ophthalmology
      • Ophthalmology Glaucoma
      • Ophthalmology Retina
      • YO Info
      • Scope
    • Subspecialties
      • Cataract/Anterior Segment
      • Comprehensive Ophthalmology
      • Cornea/External Disease
      • Glaucoma
      • Neuro-Ophthalmology/Orbit
      • Ocular Pathology/Oncology
      • Oculoplastics/Orbit
      • Pediatric Ophthalmology/Strabismus
      • Refractive Management/Intervention
      • Retina/Vitreous
      • Uveitis
    • IRIS Registry
      • About
      • Using the Registry
        • User Guide
        • Medicare Reporting
        • Maintenance of Certification
        • Non-EHR Reporting
      • Sign Up
        • Application Process
        • Why Participate
        • Once You've Applied: Getting Started
        • What Practices Are Saying About the Registry
      • Requirements
        • EHR Systems
        • Data & Technical Needs
      • Research
      • Registry Dashboard
      • News
      • Medicare & MIPS
    • Medicare Information
    • Diversity, Equity, and Inclusion
  • For Practice Management
    • Managing Your Practice
      • Managing Your Practice Topics
      • Coronavirus Resources
      • Reopening & Recovery
      • Practice Forms Library
      • Practice Management News and Advice
      • AAOE-Talk
      • Video Library
      • Ophthalmology Job Center
      • Benchmarking and Salary Tools
      • Academy Consultations
      • Consultant Directory
    • Coding
      • Coding Topics
      • Codequest Events
      • Ask the Coding Experts
      • Coding Updates and Resources
      • Coding for Injectable Drugs
      • EM Documentation
      • ICD-10-CM
      • Ophthalmic Coding Specialist (OCS) Exam
      • Retina
      • Savvy Coder
    • Webinars and Events
      • Annual Meeting
        • Master Classes
        • Coding Sessions
        • Submit an Instruction Course
      • Codequest Courses
      • Mid-Year Forum
      • Webinar Recordings
      • Upcoming Webinars
    • IRIS Registry
      • Merit-Based Incentive Payment
    • Medicare and MIPS
      • MIPS
        • Quality
        • Promoting Interoperability
        • Improvement Activities
        • Cost
        • Avoid a Penalty
      • Resources
      • Medicare Participation Options
      • Medicare Advantage Plans
      • New Medicare Card
      • Provider Enrollment, Chain and Ownership System (PECOS)
    • Regulatory Compliance
      • HIPPA Resources
      • Office of Inspector General
      • Audits
      • OSHA
    • AAOE Membership
      • Join AAOE
      • Membership Benefits
      • Renew/Pay Dues
    • About AAOE
      • AAOE Board of Directors
      • AAOE Content Committee
      • Volunteer Opportunities
  • For Public & Patients
    • Eye Health A-Z
    • Symptoms
    • Glasses & Contacts
    • Tips & Prevention
    • News
    • Ask an Ophthalmologist
    • Patient Stories
    • No Cost Eye Exams
    • Español
      • A - Z de Salud Ocular
      • Síntomas
      • Anteojos y Lentes de Contacto
      • Consejos y Prevención
      • Noticias
      • Relatos de Pacientes
      • Exámenes de la vista sin costo
      • English
  • AAO 2022
    • Meeting Information
      • Past and Future Meetings
      • Mobile Meeting Guide
      • Contact Information
      • Annual Meeting News
      • Health and Safety
      • Policies and Disclaimers
    • Program
      • Program Highlights
      • Subspecialty Day
      • Virtual Meeting
      • Program Committees
      • CME
      • Meeting Archives
    • Expo
    • Registration
    • Hotels & Travel
      • Hotel Reservation Information
      • Chicago
      • International Attendees
      • Hotel Meeting Space
    • Presenter Central
      • Presenter Central
      • Abstract Selection Process
      • Submission Policies
      • Subject Classification/Topics
      • Instruction Courses and Skills Transfer Labs
      • Papers and Posters
      • Videos
      • Grand Rounds Symposium
      • Program Participant and Faculty Guidelines
      • Faculty Development Program
    • Exhibitors
      • Exhibitor Central
      • Exhibitor Portal Information
      • Exhibitor Prospectus
      • New Exhibiting Companies
      • Exhibitor Resources
      • International Exhibitors
      • Promotional Opportunities
      • Exhibitor Hotel Reservations
  • About
    • Who We Are
      • What We Do
      • About Ophthalmology
      • The Eye Care Team
      • Ethics and the Academy
      • History
      • Museum of Vision
      • Values
    • Governance
      • Council
      • Board of Trustees
      • Committees
      • Academy Past Presidents
      • Secretariats
      • Elections
      • Academy Blog
      • Academy Staff Leadership
    • Leadership Development
    • Awards
      • Laureate Recognition Award
      • Outstanding Advocate Award
      • Outstanding Humanitarian Service Award
      • International Blindness Prevention Award
      • Distinguished Service Award
      • Guests of Honor
      • Secretariat Award
      • Straatsma Award
      • Achievement Award Program
      • Artemis Award
      • EnergEYES Award
      • International Education Award
      • International Scholar Award
      • Commitment to Advocacy Award
      • Visionary Society Award
    • Financial Relationships
    • Policy Statements
    • Related Organizations
      • Subspecialty/Specialized Interest Society Directory
      • State Society Directory
      • Subspecialty/Specialized Interest Society Meetings
      • State Society Meetings
      • Resources for Societies
    • Year in Review
      • 2020 Year in Review
  • Foundation
    • About
      • 2020-2021 Annual Report
      • Annual Report Archives
      • News From the Chair
      • Foundation Staff
    • Our Impact
      • Partners for Sight
      • Donor Spotlights
      • Global Ophthalmic Community
      • Sponsorships
      • Patients and the Public
    • Giving Options
      • Our Supporters
      • Estate and Planned Giving
      • Ophthalmic Business Council
      • Parke Center Campaign
      • Minority Ophthalmology Mentoring Campaign
      • Museum of the Eye Campaign
    • Orbital Gala
      • Why Attend
      • Photo Recap
      • Corporate Support Opportunities
      • Tribute Gifts
      • Silent Auction
      • Corporate Sponsors
    • Donate
    • Museum of the Eye Campaign
      • Museum Supporters
  • Museum of the Eye
    • Visit
    • What's On
      • Museum Galleries
      • Special Exhibitions
      • Current Events
      • Past Events
    • Explore
      • Research and Resources
      • Collection Search
      • Previous Exhibits
      • Oral Histories
      • Biographies
    • Volunteer
    • Mailing List
    • Donate
    • About the Museum
      • Museum Blog
  • Young Ophthalmologists
    • YO Info
    • Learn to Bill
    • Engage with the Academy
  • Senior Ophthalmologists
    • Scope
    • Practice Transitions
  • International Ophthalmologists
    • Global Programs and Resources for National Societies
    • Awards
    • Global Outreach
  • Residents
  • Medical Students
×
Shop
Log In Create an Account
  • For Ophthalmologists
  • For Practice Management
  • For Public & Patients
  • Coronavirus
  • About
  • Foundation
  • Museum of the Eye
  • COVID-19
  • Journals
  • Education
    • Education
    • Courses
    • Cases
    • Learning Plans
    • Interactive
    • Focal Points
    • Wills Eye Manual
    • Disease Reviews
    • Clinical Webinars
    • Diagnose This
    • Self-Assessments
    • Education Centers
      • Glaucoma Education Center
      • Pediatric Ophthalmology Education Center
      • Laser Surgery Education Center
      • Oculofacial Plastic Surgery Center
      • Redmond Ethics Center
      • Myopia Resources
      • Thyroid Eye Disease Resources
  • Guidelines
    • Practice Guidelines
    • Preferred Practice Patterns
    • Clinical Statements
    • Ophthalmic Technology Assessments
    • Patient Safety Statements
    • Complementary Therapy Assessments
    • Compendium Guidelines
    • Medical Information Technology
    • Low Vision
    • Choosing Wisely
    • Eye Care for Older Adults
    • Eye Disease Statistics
    • About the Hoskins Center
    • Artificial Intelligence
    • Premium IOLs
    • Patient-Reported Outcomes with LASIK Symptoms and Satisfaction
  • Multimedia
    • Multimedia Library
    • Video
      • 1-Minute Videos
      • Presentations and Lectures
      • Master Class Videos
      • Basic Skills Videos
      • Clinical and Surgical Videos
      • Interviews
      • Resident Lectures
      • Submit a Video
      • YO Video Contest
    • Podcasts
      • Browse Podcast Archive
      • Experts InSight Podcast
      • Ophthalmology Journal Podcast
    • Images
      • Submit an Image
  • News
    • Clinical News
    • Editors' Choice
    • Headlines
    • Current Insight
  • CME
    • CME Central
    • Claim CME Credit and View Transcript
    • CME Planning Resources
    • Complete Your Financial Disclosure
    • Joint Sponsorship Portal
    • LEO Continuing Education Recognition Award
    • Safe ER/LA Opioid Prescribing
    • Check Your Industry Payment Records
  • MOC
  • Residents
    • Resident Education Home
    • Browse All Resident Content
      • Courses
      • Flashcards and Study Presentations
      • Interactive Cases and Simulations
      • Videos
      • Webinars
    • Cataract Master
    • Diversity and Inclusion Education
    • News and Advice from YO Info
    • OKAP and Board Exam Resources
      • OKAP Exam
      • Board Prep Resources
      • OKAP and Board Review Presentations
      • Study Flashcards
    • Pediatric Ophthalmology Education Center
    • PGY-1 and PGY-2 Resources
    • Resident Knowledge Exchange
    • Simulation in Resident Education
    • Clinical Education /
    • Book Excerpts /
    • Basic and Clinical Science Course - Excerpt
  • 2020–2021 BCSC Basic and Clinical Science Course™

    Go to Academy Store Learn more and Purchase.

    1 Update on General Medicine

    Chapter 11: Behavioral and Neurologic Disorders

    Neurologic Disorders

    Parkinson Disease

    Parkinson disease (PD), also known as paralysis agitans, is a neurodegenerative condition that is characterized by tremor, bradykinesia, and rigidity. Parkinson disease usually affects persons older than 50 years, and its incidence rises dramatically after age 60. Early-onset PD (prior to age 50) is seen in less than 10% of cases; risk factors for early onset are still unclear. Worldwide, approximately 7.5 million people are affected with the disease; this number is estimated to rise to over 9 million by 2030. Many studies indicate a male predominance. The differential diagnosis for Parkinson disease includes other neurodegenerative disorders such as dementia with Lewy bodies, corticobasal degeneration, multiple system atrophy, and progressive supranuclear palsy.

    Etiology

    The basal ganglia are a complex of deep gray-matter nuclei that includes the corpus striatum, globus pallidus, and substantia nigra. These structures regulate the initiation and control of movement. Patients with Parkinson disease have typically lost 80% or more of the dopamine-producing neurons in the substantia nigra. Depletion of dopamine in the complex nigrostriatal pathway produces an imbalance in inhibitory and excitatory neuronal signals, leading to the cardinal signs of Parkinson disease.

    Although most cases are sporadic, genetic factors are implicated in the pathogenesis, especially in early-onset cases. At least 5 possible causative genes have been identified, and the number of Parkinson-like disorders associated with specific genetic defects is increasing. Many of these defects appear to be involved in cellular protein metabolism. Overall, Parkinson disease seems to have a multifactorial etiology that includes genetic predisposition, environmental factors, and age-related changes in neuron metabolism.

    Symptoms

    The first symptom of Parkinson disease is usually tremor of a limb at rest. Other common symptoms include bradykinesia, rigidity, a shuffling gait, postural instability, and stooped posture. Persons with Parkinson disease often have reduced facial expressions and speak in a soft voice. The disease is associated with nonmotor features such as depression (in up to 50% of cases), dementia, personality changes, sexual difficulties, sleep disorders, and hallucinations.

    Treatment

    There is currently no cure for Parkinson disease. Dopamine replacement, with medications such as levodopa, is the main treatment. Dopamine itself cannot be given because it does not cross the blood–brain barrier. Although levodopa helps at least three-fourths of patients with Parkinson disease, not all symptoms respond equally to the drug. Bradykinesia and rigidity respond best, whereas tremor may only be marginally reduced. Problems with balance and other symptoms may not be alleviated at all. Patients are often given levodopa combined with carbidopa. The combination of the 2 together delays the conversion of levodopa into dopamine until it reaches the brain, diminishing some of the adverse effects that often accompany levodopa therapy alone.

    After years of therapy, patients may experience a “wearing-off” effect that occurs about 4 hours after a dose of levodopa, when symptoms may return. Catechol O-methyltransferase inhibitors such as entacapone extend the duration of the levodopa effect and reduce the “off ” time by inhibiting the methylation of levodopa and dopamine.

    Several additional therapies for Parkinson disease exist, and research is dedicated to finding more effective modalities. Dopamine agonists (bromocriptine, pramipexole, ropinirole, rotigotine, and apomorphine) stimulate dopamine receptors in the brain and may delay the need for levodopa. The monoamine oxidase (MAO) type B inhibitors selegiline, rasagiline, and safinamide may modestly improve symptoms of Parkinson disease. Based on information obtained from animal studies, the first 2 may also have neuroprotective properties and are therefore considered to be potential disease-modifying agents. The glucagon-like peptide-1 (GLP-1) drug exenatide, which is used in the treatment of type 2 diabetes mellitus, has also demonstrated some potential neuroprotective effect and is currently being studied. Anticholinergic drugs such as trihexyphenidyl and benztropine have a short-lived effect controlling tremor and rigidity. However, only about half of patients respond to anticholinergics, and typical anticholinergic adverse effects can be problematic.

    Amantadine, an antiviral drug, may be used during the early stages of the disease, either alone or in combination with anticholinergics or levodopa. After several months, the effectiveness of amantadine wears off in one-third to one-half of patients.

    Modern surgical treatments consist primarily of deep-brain stimulation and pallidotomy or thalamotomy. The dopamine deficiency in patients with Parkinson disease results in excitation of the globus pallidus, which in turn inhibits thalamic activity. Both surgical techniques serve to suppress this excessive globus pallidus activity. Deep-brain stimulation is initially safer than pallidotomy but requires intensive adjustments and lifelong maintenance, given the risk of hardware complications and infection. Pallidotomy carries the risk of complications such as stroke and hemorrhage, as well as the risk of irreversible adverse effects, and is seldom performed.

    • Ferreira M, Massano J. An updated review of Parkinson’s disease genetics and clinicopathological correlations. Acta Neurol Scand. 2017;135(3):273–284.

    • Kalia LV, Kalia, SK, Lang AE. Disease-modifying strategies for Parkinson’s disease. Mov Disord. 2015;30(11):1442–1450.

    Ophthalmic considerations Patients with Parkinson disease may present with numerous ophthalmologic findings. These findings can be divided into eyelid disorders and ocular motor abnormalities. Eyelid disorders include seborrheic dermatitis and blepharitis, apraxia of eyelid opening, eyelid retraction, decreased blinking (with secondary dry eye), and blepharospasm. Ocular motor abnormalities include convergence insufficiency, limitation of upgaze, saccadic abnormalities, square-wave jerks, and oculogyric crisis. Patients commonly report difficulty with reading and symptoms related to ocular surface abnormalities.

    Drug-related adverse effects may also be superimposed, especially for patients on anticholinergic medications, which may exacerbate dry eyes and cause accommodative changes or precipitate angle-closure glaucoma. Over 30% of patients with coexisting ocular disease and reduced vision may experience formed recurrent hallucinations characteristic of Charles Bonnet syndrome. However, this syndrome is not specific to Parkinson disease because it can be seen with other neurodegenerative conditions. Likewise, visual hallucinations can also occur as a result of treatment. This adverse effect has been reported in particular with the use of levodopa and anticholinergic agents. The drug amantadine has been reported to cause corneal infiltrates and edema in rare cases.

    Excerpted from BCSC 2020-2021 series: Section 1 - Update on General Medicine. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.

  • Most Commented
    Loading, please wait...
    There are no comments available.
    Most Viewed
    Loading, please wait...
    Most Viewed content is not available.
  • The Academy Store
    2022-2023 Basic and Clinical Science Course, Complete Print Set
    2022-2023 Basic and Clinical Science Course, Complete eBook Set
    2022-2023 Basic and Clinical Science Course, Complete Print and eBook Set
    2022-2023 Basic and Clinical Science Course, Residency Print Set
    2022-2023 Basic and Clinical Science Course, Residency eBook Set
    2022-2023 Basic and Clinical Science Course Complete Set
    2022-2023 Basic and Clinical Science Course Residency Set
    2022-2023 Basic and Clinical Science Course, Section 01: Update on General Medicine
    2022-2023 Basic and Clinical Science Course, Section 02: Fundamentals and Principles of Ophthalmology
    2022-2023 Basic and Clinical Science Course, Section 03: Clinical Optics and Vision Rehabilitation
    2022-2023 Basic and Clinical Science Course, Section 04: Ophthalmic Pathology and Intraocular Tumors
    2022-2023 Basic and Clinical Science Course, Section 05: Neuro-Ophthalmology
    2022-2023 Basic and Clinical Science Course, Section 06: Pediatric Ophthalmology and Strabismus
    2022-2023 Basic and Clinical Science Course, Section 07: Oculofacial Plastic and Orbital Surgery
    2022-2023 Basic and Clinical Science Course, Section 08: External Disease and Cornea
    2022-2023 Basic and Clinical Science Course, Section 09: Uveitis and Ocular Inflammation
    2022-2023 Basic and Clinical Science Course, Section 10: Glaucoma
    2022-2023 Basic and Clinical Science Course, Section 11: Lens and Cataract
    2022-2023 Basic and Clinical Science Course, Section 12: Retina and Vitreous
    2022-2023 Basic and Clinical Science Course, Section 13: Refractive Surgery
    2022 IRIS Registry (Intelligent Research in Sight) Preparation Kit
    Presbyopia-Correcting IOLs
    Retina Patient Education Video Collection
    Cataract and Refractive Surgery Patient Education Video Collection
    Glaucoma Patient Education Video Collection
    Oculoplastics Patient Education Video Collection
    Pediatrics Patient Education Video Collection
    2022 Coding Coach: Complete Ophthalmic Coding Reference 
    2022 CPT: Complete Pocket Ophthalmic Reference
    2022 Retina Coding: Complete Reference Guide
 
  • Contact Us
  • About the Academy
  • Jobs at the Academy
  • Financial Relationships with Industry
  • Medical Disclaimer
  • Privacy Policy
  • Terms of Service
  • Help
  • For Advertisers
  • For Media
  • Ophthalmology Job Center

OUR SITES

  • EyeWiki
  • International Society of Refractive Surgery

FOLLOW THE ACADEMY

Medical Professionals

  • Facebook
  • Twitter
  • LinkedIn
  • YouTube

Public & Patients

  • Facebook
  • Twitter
  • Instagram
  • YouTube

Museum of the Eye

  • Facebook
  • Twitter
  • Instagram
  • YouTube
  • Trip Advisor
  • Yelp
© American Academy of Ophthalmology 2022