Ophthalmology: Eye Exam and Vision Loss Flashcards

Questions and Answers

What is the uveal tract made up of?

Iris, Ciliary body, Choroid

What is happening in the case of bleeding in small conjunctival or Tenon's vessels?

This is not sclera bleeding.

What percentage of refractive power does the cornea provide?

2/3

What percentage of refractive power does the lens provide?

1/3 Signup and view all the answers

What is emmetropia?

The normal relationship between the refractive power of the eye and its shape. Signup and view all the answers

What is hyperopia?

Farsightedness, where the eye is too short and images focus behind the retina. Signup and view all the answers

What is myopia?

Nearsightedness, where the eye is too long and images focus in front of the retina. Signup and view all the answers

What is astigmatism?

Defective curvature of the cornea or lens of the eye. Signup and view all the answers

What happens in presbyopia?

The lens loses its ability to accommodate and becomes more convex in structure. Signup and view all the answers

What is visual acuity (VA)?

The smallest object a person can identify at a given distance from the eye. Signup and view all the answers

When is testing visual acuity most critical?

Before age 7, especially in children. Signup and view all the answers

What is the purpose of anterior chamber depth assessment?

To indicate when narrow angle is suspected prior to dilation. Signup and view all the answers

What is the normal range of intraocular pressure (IOP)?

8-21 mmHg Signup and view all the answers

What is the use of tropicamide?

It is a mydriatic drop used to dilate the eye for better visualization. Signup and view all the answers

What is the purpose of proparacaine HCl?

It is a topical anesthetic used for examination of the eye. Signup and view all the answers

What is considered normal visual acuity?

20/20, with a range from 20/12 to 20/25 being acceptable. Signup and view all the answers

What is legal blindness?

20/200 or less corrected with the better eye, or less than 120 degrees of field. Signup and view all the answers

What are the steps for visual acuity testing?

<ol> <li>Stand at proper distance 2. Test OD first, then OS 3. Use correction if available 4. Occlude fellow eye 5. Correctly identify half of the letters.</li> </ol> Signup and view all the answers

What term describes adhesions of the iris to the lens of the eye?

Posterior synechiae Signup and view all the answers

Where must the lesion be located if a patient is presenting with an APD?

Anterior to the optic chiasm. Signup and view all the answers

How many cardinal fields of vision are there?

6 Signup and view all the answers

How many positions of gaze are there?

9 Signup and view all the answers

What is the purpose of setting the diopter wheel during an exam?

To clarify the patient's retina and visualize properly. Signup and view all the answers

Study Notes

Eye Structures and Functions

Uvea/Uveal Tract: Comprises the iris, ciliary body, and choroid.
Vision Terminology: Cornea provides 2/3 of the refractive power while the lens contributes 1/3.

Vision Conditions

Emmetropia: The ideal relationship between the refractive power and eye shape for proper light focusing on the retina.
Hyperopia (Farsightedness): Caused by a short eye resulting in images focusing behind the retina; corrected with convex lenses.
Myopia (Nearsightedness): Caused by an elongated eye with images focusing in front of the retina; corrected with concave lenses.
Astigmatism: Results from irregular curvature of the cornea or lens, leading to distorted vision.
Presbyopia: Loss of lens accommodation around mid-40s, typically affecting near vision; correction includes glasses, contacts, or refractive surgery, but not for presbyopia itself.

Visual Acuity and Testing

Visual Acuity (VA): Measures the smallest identifiable object at a specific distance; important to include corrections if needed.
Basic Terminology:
- OD = Oculus Dexter (right eye)
- OS = Oculus Sinister (left eye)
- OU = Oculus Uterque (both eyes)
- cc = with correction
- sc = without correction
Critical Age for Testing: Visual acuity testing is crucial in children before age 7.
Testing Methods: Includes confrontation visual field testing, color vision testing, fluorescein staining, and upper lid eversion.

Pressure and Dilation

Tonometry: Measures intraocular pressure (normal range 8-21 mmHg), essential for glaucoma assessment.
Mydriatic Drops (Tropicamide): Used for pupil dilation to enhance eye visualization during exams.
Topical Anesthetic (Proparacaine HCl): Applied for eye examinations requiring contact.

Visual Acuity Measurement

Normal Visual Acuity: "Normal" defined as 20/20 but can range from 20/12 to 20/25.
Moderate/Low Vision: Defined as visual acuity of 20/80 to 20/160.
Legal Blindness: Considered as 20/200 or worse in the better eye, or having less than 120 degrees of visual field.

Visual Testing Procedure

Steps for visual acuity testing include:
- Ensure patient is at the correct distance from the chart.
- Test OD followed by OS, using correction if available.
- Ensure the fellow eye is properly occluded.
- Correctly identifying half or more of the letters on the line is required to pass.

Adverse Conditions and Lesions

Posterior Synechiae: Refers to iris adhesions to the lens, potentially affecting pupil assessment.
Afferent Pupillary Defect (APD): Indicates lesions anterior to the optic chiasm.

Eye Assessment Techniques

Cardinal Fields and Gaze: There are 6 cardinal fields of vision and 9 positions of gaze.
Examination Steps: Adjust lighting, focus settings, and approach the eye at a 15-degree angle to assess the optic disc and surrounding retinal vessels.

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Description

Test your knowledge on ophthalmology with these flashcards focused on eye exams, vision loss, and related drugs. Each card presents essential terms and definitions that are crucial for understanding the anatomy and functionality of the eye. Perfect for medical students and health professionals interested in this specialized field.