LENSES

By: Carmen Willings
teachingvisuallyimpaired.com

Reports should indicate what a student's uncorrected and corrected visual acuities are. If a student's vision can be corrected, even mildly, they will typically be prescribed glasses or contacts. 

---

Why were the glasses prescribed?

It is important to know why the glasses have been prescribed. Correcting a refractive error (such as myopia or hyperopia) is only one of the reasons that these may be prescribed. ​Glasses may be prescribed with a prism for a muscle imbalance or they may be recommended to protect the eyes. If the glasses are prescribed for near, they should be removed for distance viewing and vice versa if recommended by the doctor (some students will be able to leave them on as it will not have a significant impact). Glasses that are prescribed for myopia, or nearsightedness, will have a minus lens. Glasses prescribed for hyperopia will have a plus lens.

Types of Lenses

​The type of lenses that are prescribed can tell you a lot about the student's eye condition. The stronger the lens, the more significant the uncorrected vision. Keep in mind that even if a student is prescribed glasses, it doesn't necessarily mean that the student's vision can be fully corrected. This is because glasses cannot correct all types of visual impairments.

A convex, or plus lens

A convex lens bulges outward, converges light rays and increases the size of an image being viewed. A plus lens directs light rays entering the eye so they focus on the retina instead of behind the retina as convex lenses correct hyperopia, a condition in which the eye is underpowered. Lens power that is greater than +12D could mean that the student has no crystalline lens (due to cataract surgery or aphakia) or the student has extreme farsightedness.

A concave, or minus lens

A concave lens bulges inward, diverges light rays and decreases the size of the image received or can be used to converge light rays so that they focus on the retina, rather than in front of it. A very strong minus lens indicates extreme nearsightedness, also referred to as high myopia.

Plano lenses

A plano lens does not bulge inward or outward and is not for correction in eyeglasses. A student may be prescribed plano lenses if they have no vision in one eye and the lens is used to "balance" the prescription for the other eye. It may also be used for cosmetic reasons or for safety reasons.

Prism Lenses

Prism lenses are often prescribed for persons who have strabismus for the purpose of redirecting the rays of light entering the eye. Prisms may also be used for persons with visual field neglect to cue the person that additional information exists in the neglected field.

​Other Terms...

• The sphere is the amount in diopters of correction to sharpen vision to best correction.
• The cylinder power is the amount of lens power needed to correct astigmatism.
• The axis is a number that indicates location of cylinder power in lens for astigmatism. 
• Prism is added to some prescriptions to compensate for eye alignment problems.
• Base refers to the location of the thickest edge of the prism and direction it redirects light. 

Sample Eyeglasses Prescription

		Sphere	Cylinder	Axis	Prism	base
Distance	OD	-3.75			0.5	down
	OS	-4.25	-0.50	180	0.5	up

Learn More...

All About Vision

Gary Heiting, OD has written a great article for All About Vision entitled "How to Read Your Eyeglass Prescription." This information can be very helpful when interpreting the eye report!

Free Membership

Sign up for free membership to access the FREE downloadable templates, handbooks and handouts on the Printables page. Simply click on the Log In | Register link in the navigation bar. If you haven't joined yet, you will be prompted to create a password. ​

Job Posting Service

Shop

TVI's Guide to Teaching the ECC: An Activities Based Curriculum for Teaching Students who are Blind or Visually Impaired

$50.00

Written specifically for fellow itinerant Teachers of Students with Visual Impairments (TVI’s), this book consists of over 400 activities and topic areas of discussion for instructing students in the Expanded Core Curriculum. The activities are age-neutral and multi-sensory and therefore can meet the needs of the broad range of students served on an itinerant caseload serving. The activities can be individualized to the students various learning modalities and scaffold in order to challenge students but ensure success. Select those activities that align with the student’s learning objects based on the student’s unique visual needs and academic and developmental level.

The core activities listed in the Activity section can be adapted to each thematic unit. These include:

• Object Characteristic Activities
• Quantity & Number Concepts
• Time Concept Activities
• Environment & Job Awareness Activities
• Listening Skills Activities
• Reading Foundation Activities
• Reading Fluency Activities
• Braille Basics Activities
• Writing Activities
• Tactual Efficiency Activities
• Developing Skillful Hands Activities
• Visual Efficiency Activities
• Optical Device Instruction Activities
• Recipe Activities

In addition to the core activity areas, each of the 32 Thematic Units incorporates additional unique ECC concepts and skills providing you with a years’ worth of activities. These units are cyclical and can be used repeatedly to help students build on prior knowledge and develop a deeper understanding of concepts. Each unit includes suggestions for activity adaptation associated with the unit. These include lists of objects, possible community based experiences, environmental print, poems, children & young reader books, children's songs, pop culture songs, movies, and websites.

Unique Concepts within the Units include:

• Self Advocacy Activities (e.g. advocating for safe classroom, presenting to class on visual impairment, requesting help and more)
• Social Skills Activities (e.g. Being bullied or teased, giving and receiving compliments, body language, "I" messages when upset and more)
• Recreation & Leisure Activities (e.g. exploring interest areas, getting involved in clubs and sports, playing games, and more)
• O&M Support Activities (e.g. Suggestions for community based experiences, dog guide information, locations in the school, bioptics, ride sharing, traffic signs, and more)
• Independent Living Skill Activities (e.g. chores, being responsible, using tools, recipe suggestions, hygiene, staying healthy, labeling foods and products, and more)
• Sensory Efficiency Activities (e.g. unique sensory experiences related to the unit, unique optical device activities, and more)
• Compensatory Activities (e.g. organizing materials, study habits, and many unique concepts related to the unit)
• Career & Vocational Activities (e.g. job awareness, completing applications, job task suggestions, and more)

Although the intended audience of this resource is fellow Teachers of Students with Visual Impairments, special education teachers may find these activities beneficial to the students in their classrooms as the activities are multisensory and include life skills and concepts needed by all students. This resource, however, is not intended to take the place of a Teacher of Students with Visual Impairments (TVI). Readers are advised to consult their own TVI’s regarding instruction in the ECC and the unique visual needs of the student’s served in their programs.

Note: This curriculum is a digital pdf download. Once you make your purchase you will be directed to an order confirmation page where you will find the download link. This download will also be included on the receipt sent to the email address you provide. The pdf download can be found directly under the order number.

Each download is intended for single instructor use per copyright. Thank you for helping me preserve the content and not distributing copies to third parties.

Product details

Digital pdf download: 364 pages (11 pt font)

Publisher: Teaching Students with Visual Impairments

Author: Carmen Willings

Language: English

Shop

Visual Efficiency & Magnifier Fluency Grab & Go ECC Supplements

$20.00

This workbook is a pdf download that can be printed on demand for use with students. It contains five different types of worksheets for developing visual motor skills and near magnifier fluency skills particularly with the use of a video magnifier. As a supplement to the TVI’s Guide to the ECC, the worksheets correspond to each of the 32 ECC Thematic units. The worksheets, along with a list of environmental print for each thematic unit, are designed to help students refine their visual motor skills while reinforcing ECC concepts presented in the thematic units.  

Visual Efficiency & Near Magnifier Fluency Worksheet Details:

Digital pdf download: 210 pages

Publisher: Teaching Students with Visual Impairments

Author: Carmen Willings

Language: English

Shop