Toronto Guide to Clinical Ophthalmology for Physicians and Medical Trainees

TORONTO GUIDE TO CLINICAL

OPHTHALMOLOGY

FOR PHYSICIANS AND MEDICAL TRAINEES

TORONTO GUIDE TO CLINICAL

OPHTHALMOLOGY

FOR PHYSICIANS AND MEDICAL TRAINEES

DANIEL J. WEISBROD, MD, FRCSC

TINA FELFELI, MD

SHERIF R. EL-DEFRAWY, MD, PhD, FRCSC

Contents

Contributors

Figures

Introduction

1 Red eye

2 The lens and cataract

3 Glaucoma

4 Retina

5 Neuroophthalmology

6 Oculoplastics and orbital diseases

7 Ocular trauma

8 Pediatric ophthalmology

9 A reference on anatomy of the eye

Abbreviations

About the authors

Index

Contributors

The authors would like to thank all chapter editors and the rest of our team, who have made a significant contribution to this initiative, and without whom this project would not have been possible.

Chapter editors

CHAPTER 1 – RED EYE

Amrit S. Rai, MD

Resident physician, Department of Ophthalmology and Vision Sciences

University of Toronto

Amandeep S. Rai, MD, FRCSC

Lecturer, Department of Ophthalmology and Vision Sciences, Kensington Vision and Research Centre

University of Toronto

CHAPTER 2 – THE LENS AND CATARACT

Brian G. Ballios, MD, PhD

Resident physician, Department of Ophthalmology and Vision Sciences

University of Toronto

Hall F. Chew, MD, FRCSC

Associate professor, Department of Ophthalmology and Vision Sciences, Sunnybrook Health Sciences Centre

University of Toronto

CHAPTER 3 – GLAUCOMA

Angela Q. Zhang, MD

Resident physician, Department of Ophthalmology and Vision Sciences

University of Toronto

Matthew B. Schlenker, MD, FRCSC

Assistant professor, Department of Ophthalmology and Vision Sciences, Kensington Vision and Research Centre

University of Toronto

CHAPTER 4 – RETINA

Samuel A. Minaker, MD, MSc

Resident physician, Department of Ophthalmology and Vision Sciences

University of Toronto

Panos G. Christakis, MD, FRCSC

Assistant professor, Department of Ophthalmology and Vision Sciences, Kensington Vision and Research Centre

University of Toronto

Efrem D. Mandelcorn, MD, FRCSC

Associate professor, Department of Ophthalmology and Vision Sciences, Toronto Western Hospital, University Health Network

University of Toronto

CHAPTER 5 – NEUROOPHTHALMOLOGY

Lili Tong, MD

Resident physician, Department of Ophthalmology and Vision Sciences

University of Toronto

Jonathan A. Micieli, MD, FRCSC

Assistant professor, Department of Ophthalmology and Vision Sciences, Kensington Vision and Research Centre

University of Toronto

Edward A. Margolin, MD, FRCSC

Associate professor, Department of Ophthalmology and Vision Sciences, Mount Sinai Hospital

University of Toronto

CHAPTER 6 – OCULOPLASTICS AND ORBITAL DISEASES

Jason M. Kwok, MD

Resident physician, Department of Ophthalmology and Vision Sciences

University of Toronto

Harmeet S. Gill, MD, FRCSC

Assistant professor, Department of Ophthalmology and Vision Sciences, Sunnybrook Health Sciences Centre, and Mount Sinai Hospital

University of Toronto

CHAPTER 7 – OCULAR TRAUMA

Bryon R. McKay, MD, PhD

Resident physician, Department of Ophthalmology and Vision Sciences

University of Toronto

Edsel B. Ing, MD, FRCSC

Associate professor, Department of Ophthalmology and Vision Sciences, Michael Garron Hospital, Toronto East Health Network

University of Toronto

Kylen D. McReelis, MD, FRCSC

Lecturer, Department of Ophthalmology and Vision Sciences, Sunnybrook Health Sciences Centre, and Peterborough Regional Health Centre

University of Toronto

CHAPTER 8 – PEDIATRIC OPHTHALMOLOGY

Yelin Yang, MD

Resident physician, Department of Ophthalmology and Vision Sciences

University of Toronto

Michael J. Wan, MD, FRCSC

Assistant professor, Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children

University of Toronto

CHAPTER 9 – A REFERENCE ON ANATOMY OF THE EYE

Jeremy A. Goldfarb, MD

Resident physician, Department Ophthalmology and Vision Sciences

University of Toronto

Hannah H. Chiu, MD, FRCSC

Lecturer, Department of Ophthalmology and Vision Sciences, St. Michael’s Hospital, and William Osler Health System

University of Toronto

Acknowledgements

ILLUSTRATIONS

Cynthia Watada

Freelance medical illustrator, Oakville, Ontario

Manokaraananthan Chandrakumar, MSc, MBA

Executive assistant, Department of Ophthalmology and Vision Sciences

University of Toronto

CLINICAL IMAGE CONTRIBUTION

Sultan Aldrees, MBBS, MSc

Resident physician, Department of Ophthalmology and Vision Sciences

University of Toronto

Asim Ali, MD, FRCSC

Associate professor, Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children

University of Toronto

Catherine M. Birt, MD, FRCSC

Associate professor, Department of Ophthalmology and Vision Sciences, Sunnybrook Health Sciences Centre

University of Toronto

William A. Cantore, MD

Department of Ophthalmology and Neurology Penn State Hershey Eye Center

Milton S. Hershey Medical Center

Kenneth Eng, MD, FRCSC

Assistant professor, Department of Ophthalmology and Vision Sciences, Sunnybrook Health Sciences Centre

University of Toronto

James P. Farmer, MD, FRCSC, FRCPC

Associate professor, Ophthalmology and Pathology and Molecular Medicine

Queen’s University

Assistant professor, Ophthalmology and Pathology and Laboratory Medicine, EORLA

University of Ottawa

John H. Fowler, MD, PhD, FRCPC

Associate professor, Department of Ophthalmology and Vision Sciences

University of Toronto

Peter J. Kertes, MD, FRCSC

Professor, Department of Ophthalmology and Vision Sciences, Sunnybrook Health Sciences Centre University of Toronto

Stephen P. Kraft, MD, FRCSC

Professor, Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children

University of Toronto

Shaobo Lei, MD, MSc, PhD

Resident physician, Department of Ophthalmology and Vision Sciences

University of Toronto

Allan R. Slomovic, MD, FRCSC, MSc

Professor, Department of Ophthalmology and Vision Sciences, Toronto Western Hospital, University Health Network

University of Toronto

Agnes Wong, MD, PhD, FRCSC

Professor, Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children

University of Toronto

TECHNICAL ASSISTANCE WITH ACQUISITION OF IMAGES

Beth A. Selkirk, COA

Ophthalmic photographer, Department of Ophthalmology and Vision Sciences, Sunnybrook Health Sciences Centre

University of Toronto

Cynthia VandenHoven, BAA, CRA

Medical imaging specialist, Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children

University of Toronto

ADMINISTRATIVE ASSISTANCE

Elizabeth Den Hartog

Business officer, Department of Ophthalmology and Vision Sciences

University of Toronto

Figures

The lens and cataract

FIGURE 2.1 ACCOMMODATION

FIGURE 2.2 THE 3 COMMON TYPES OF CATARACTS

Glaucoma

FIGURE 3.1 CLASSIFICATION OF GLAUCOMA

FIGURE 3.2 MECHANISM OF ANGLE CLOSURE IN RELATIVE PUPILLARY BLOCK

FIGURE 3.3 LASER PERIPHERAL IRIDOTOMY FOR RESTORING NORMAL AQUEOUS FLOW PATTERN

Neuroophthalmology

FIGURE 5.1 OPTIC NEUROPATHY TEMPORAL PROFILE

FIGURE 5.2 COMMON PATTERNS OF NEUROLOGICAL VISUAL FIELD DEFECTS

FIGURE 5.3 ALGORITHM TO DETERMINE THE CAUSE OF ANISOCORIA

FIGURE 5.4 DIFFERENTIATING CAUSES OF CRANIAL NERVE III PALSY

FIGURE 5.5 MEDIAL LONGITUDINAL FASCICULUS AND ASSOCIATED STRUCTURES

Ocular trauma

FIGURE 7.1 CLASSIFICATION OF OCULAR TRAUMA

FIGURE 7.2 CLINICAL PRESENTATION OF CRANIAL NERVE PALSIES

Anatomy of the eye

FIGURE 9.1 SECTIONAL ANATOMY OF THE EYE

FIGURE 9.2 COMPONENTS OF THE CONJUNCTIVA IN CROSS-SECTION

FIGURE 9.3 SURFACE ANATOMY OF THE EYE

FIGURE 9.4 HISTOLOGICAL CROSS-SECTION OF THE CORNEA (H&E STAIN)

FIGURE 9.5 HISTOLOGICAL CROSS-SECTION OF THE LENS (H&E STAIN)

FIGURE 9.6 ANATOMICAL STRUCTURES OF THE ANTERIOR SEGMENT

FIGURE 9.7 HISTOLOGICAL CROSS-SECTION OF THE ANTERIOR SEGMENT (H&E STAIN)

FIGURE 9.8 STRUCTURES OF THE ANTERIOR CHAMBER ANGLE AND CILIARY BODY

FIGURE 9.9 FLOW OF AQUEOUS HUMOUR

FIGURE 9.10 ANATOMICAL STRUCTURES OF THE POSTERIOR SEGMENT

FIGURE 9.11 RETINAL LAYERS AND CELL TYPES, FROM MOST-INNER TO OUTER ASPECT

FIGURE 9.12 MACULA AND FOVEA IN CROSS-SECTION

FIGURE 9.13 COURSE OF GANGLION CELL AXONS IN THE RETINA

FIGURE 9.14 VISUAL PATHWAY STRUCTURES IN THE BRAIN

FIGURE 9.15 ORBICULARIS OCULI MUSCLE AND RELATED STRUCTURES

FIGURE 9.16 STRUCTURES UNDERLYING THE ORBICULARIS OCULI MUSCLE

FIGURE 9.17 HISTOLOGICAL CROSS-SECTION OF THE UPPER EYELID (H&E STAIN)

FIGURE 9.18 GLANDS OF THE EYELID

FIGURE 9.19 MUSCLES OF THE EYELID

FIGURE 9.20 ANATOMY OF THE LACRIMAL APPARATUS

FIGURE 9.21 STRUCTURAL COMPONENTS OF THE PRECORNEAL TEAR FILM, AND ANATOMY OF THE UPPER AND LOWER EYELIDS

FIGURE 9.22 BONY WALLS OF THE ORBITAL CAVITY

FIGURE 9.23 ANTERIOR VIEW OF THE ORBITAL APEX

FIGURE 9.24 BASIC EYE MOVEMENTS

FIGURE 9.25 CARDINAL POSITIONS OF GAZE

Introduction

This first edition of the Toronto Guide to Clinical Ophthalmology represents the collective effort of many generations of staff, residents, and students from the Department of Ophthalmology and Vision Sciences at the University of Toronto, one of Canada’s foremost academic departments. This book began as an accumulation of teaching resources for trainees, and has since evolved to become an extensive resource for clinical ophthalmology.

Ophthalmology is a discipline often overlooked during medical school and in nonophthalmology medical residency training programs. This book aims to make up that gap for practising physicians, residents, and medical students. Our goal is to provide the foundational knowledge required for clinical examination, diagnosis, and management of the most commonly encountered ophthalmic diseases and ocular emergencies. We have focused on a clinical approach to make this guide practical and user-friendly. We have included a chapter on ocular anatomy at the end of the guide to supplement the clinical chapters.

The unique features of this book include:

• presentation of material that is comprehensive for the novice ophthalmology learner, and clinically relevant for physicians and trainees from all areas of medicine

• organization of content in a manner that makes this text both a study resource and day-to-day guide in clinic

• an exceptional set of clinical images, illustrations, figures, and tables

We hope that the Toronto Guide to Clinical Ophthalmology fosters the enthusiasm that inspires our department in providing only the best ophthalmic care for our patients.

Disclaimer

The publisher, authors, contributors, and editors bring substantial expertise to this reference and have made their best efforts to ensure that it is useful, accurate, safe, and reliable.

Nonetheless, practitioners must always rely on their own experience, knowledge and judgment when consulting any of the information contained in this reference or employing it in patient care. When using any of this information, they should remain conscious of their responsibility for their own safety and the safety of others, and for the best interests of those in their care.

To the fullest extent of the law, neither the publishers, the authors, the contributors nor the editors assume any liability for injury or damage to persons or property from any use of information or ideas contained in this reference.

1

Red eye

Key topics

Redness of the ocular adnexa

• eyelids

• lacrimal system

• orbit

Redness of the globe

• conjunctiva

• sclera

• cornea

• anterior chamber

In this chapter

Numerous conditions, which can be traumatic or nontraumatic, can cause a red eye. Nontraumatic conditions are often infectious or inflammatory in etiology and are covered in this chapter (see chapter 7 for traumatic causes). To elucidate a cause, it is necessary to perform a complete ocular examination to determine the primary ocular structure involved. Some causes of a red eye can be relatively benign; others, such as acute angle-closure glaucoma, are ocular emergencies.

This chapter provides an anatomic approach to the abnormalities of each of the ocular and adnexal structures that may lead to a red eye. For a summary of red eye features and key differential diagnoses, see Tables 1.3 and 1.4.

Redness of the ocular adnexa

EYELIDS

BLEPHARITIS

This common condition is characterized by eyelid inflammation. It is associated with normal ocular flora, especially Staphylococcus aureus, and can also occur with acne rosacea. Although the pathogenesis of blepharitis is thought to be multifactorial, the main classifications are based on Staphylococcal blepharitis (which causes crusting, and is associated with S. aureus) and seborrheic blepharitis (which is characterized by less inflammation, and more oily or greasy scaling).

CLINICAL FEATURES

Symptoms

• eyelash crusting

• burning sensation

• foreign body sensation

Signs

• inflammation of the eyelid margins

• madarosis (loss of eyelashes)

• collarettes (yellow flakes or scales at the base of the eyelashes)

• buildup of gland secretions and/or bacterial overgrowth

This image shows inflammation and crusting of the eyelid margins in blepharitis.

These images show crusting on the lashes, and telangectasia of the lid margin, in blepharitis.

MANAGEMENT

• Treatment strategies aim to change the composition of meibomian gland lipids to allow for better drainage.

» Eyelid hygiene: Counsel patients to apply warm compresses, and lid scrubs with baby shampoo or lid-care towelettes, to the eyelid margin for 10 minutes, 2 to 4 times daily.

» Topical medications: Prescribe mild antibiotic or steroid ointment for the eyelid margins for bacterial superinfection.

» Systemic medications: Prescribe doxycycline for unresponsive meibomitis (doxycycline promotes drainage by altering meibomian gland composition).

CLINICAL SKILLS

TEN STEPS TO TRIAGE A PATIENT PRESENTING WITH RED EYE

Step 1: Assess laterality. Is the red eye unilateral or bilateral? Unilateral cases are usually more concerning.

Step 2: Assess visual acuity and the pupils. If the patient demonstrates a decline in vision from baseline or a new relative afferent pupillary defect (RAPD), prompt referral to ophthalmology is warranted.

Step 3: Assess the severity of pain. If the patient has severe pain, prompt referral to ophthalmology is warranted.

Step 4: Assess the pattern of redness. Is it focal or diffuse?

Step 5: Asses for presence of discharge. What is the pattern (continuous or intermittent) and quality (watery or purulent) of the discharge?

Step 6: Assess other symptoms. Does the patient have symptoms of photophobia, burning, itching, or halos around light?

Step 7: Assess duration and onset. How long have the symptoms been present, and were they sudden or gradual in onset?

Step 8: Assess involvement of adnexal structures. Is there any evidence of redness or swelling of