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The Doctor Is In:
Taking Options to School
Randy Jose, OD
Associate Professor (retired)
Consultant in Vision Rehabilitation (drrandyjose@hotmail.com)
In the several years of working with children, I have consistently prescribed telescopes or monoculars for use to see the blackboard (old days) or dry erase board (recent history). The second most common "prescribed goal" was for enhancing mobility. After a number of years working with the Project DOVES program in Houston and Project PAVE program in Nashville (Dr. Anne Corn initiated this program over ten years ago) some important clinical issues in delivering optimum care to visually impaired students came to the forefront.
•	Doctors do not typically get advanced information as to the problems a student is having in the classroom or educational / service program(s). The functional assessment is not always that functional or never gets to the clinic in many cases. This will be an issue that will be addressed in a future article by Karen Blankenship and me. The point here is that without some idea as to the specific "visual" problems the student is having, most clinicians, including myself, will fall back on prescribing a reading lens for regular text print for the grade the student is in and a telescope as de-scribed above.
•	Most doctors are not familiar with the classroom setting or even know what a mobility training program consists of. It is more than using a telescope to see a street sign for independent travel. In spite of this, most telescopes will be prescribed in a power that is adequate for seeing street signs?? The educational professional must bring the school setting to the clinical setting for the low vision clinician to ensure more appropriate prescribing of devices or training protocols.
•	In our Project DOVES program, a review of the re-cords revealed that there is not enough follow up with the prescribed device after the clinical evaluation. It seems, the clinic is supposed to do all the

training. Also, when there is a problem at school, it is not brought back to the clinic. Your doctor needs to know about both the success with pre-scribed devices and problems. It wasn't until I was informed that only half the students I prescribed telescopes for seeing the dry erase board, actually worked off the board that I changed my prescribing habits. Now I ask about the classroom setting before prescribing and it is included in the preliminary report prepared for the clinical low vision examination.
For this article, I will concentrate on the telescope goals of boardwork and mobility/travel skills. Let's see if we can visualize what should happen to a telescope that was prescribed for your student after a low vision examination. In the ideal world, you would have attended the examination with the student. You would have provided the doctor with some specific problems that you have noticed the student having at school: in regards to distance vision the student seems to be having problems with getting information off the board for two classes. An OM evaluation was provided two weeks ago and the OM Instructor suggested a need for a telescope to help identify crossings and be able to use it to recognize faces. The student expressed a love for watching baseball games but has trouble following the action on the field, even when the parents take the student to the AAA team games with smaller fields. (shows parents are involved with helping improve visual functioning).
With this excellent information the doctor can now proceed with a low vision examination with these specific goals in mind. It does not mean these are the only goals that will be addressed or that others can't be addressed later. This just sets some priorities for prescribing. Let's look at how the clinician might approach the collection of clinical data and determination of a device that will resolve the presenting problems or goals.
Unaided binocular visual acuity: sets a base-line measurement for the need for additional refractive error corrections. This measurement is compared to the binocular acuity with present correction and with the binocular acuity after a low vision refraction. This allows the clinician to determine if the student

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will use the telescope with glasses or without. Many students do not get an appreciable improvement in acuity with the glasses they are wearing. The present lenses are more for safety or have some benefit for the student when doing near work and it is easier to just leave them on all the time. If the student has thick glasses and the clinician finds that they do not improve acuity much (happens a lot with albinism), the field of view through the telescope can be as much at 25% bigger when glasses are not used. If there is a concern the child will lose the glasses when removing them to use the telescope (or it is just too much of a hassle when trying to use them for the board work); contact lenses can be considered. The contact lens will allow the telescope to be held close to the eye and maintain the larger field of view. So there is a lot of information in just this one data point!!
All optical devices will have a larger field of view when held closer to the eye.
Best corrected visual acuity - each eye: The clinician will take the acuity in both the right and left eye with the obvious goal of determining which eye to prescribe for or if it might be advantageous to pre-scribe a binocular telescopic system.
•	If the acuity is the same in both eyes, it must be determined which is the dominant eye and will the student be bi-ocular and switch between eyes (usually this term is reserved for using one eye for distance and one eye for near) or will the student simply alternate which eye is being used depending on the positioning of the target.
•	If the acuity is different between the two eyes, the acuity in the better eye needs to be compared to the acuity with both eyes open. With most students, the better monocular acuity will remain the same as the binocular acuity. The student can efficiently use the better monocular eye with no modifications to the prescription.
•	If the student has better binocular acuity than the best monocular acuity, the clinician will need to give serious consideration to prescribing binocular telescopic systems.
•	If the binocular acuity is worse than the best monocular acuity, consideration must be given to making sure the student is allowed to close the worse eye when using the telescope; the student is trained to hold the telescope in the left hand 
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to use over the right eye (or visa versa) so that the arm will occlude the worse eye when viewing through the telescope; or a special patch on the upper portion of the spectacle lens can be used for occlusion only when viewing through the monocular. This latter protocol works better with bioptics.
Rivalry is an issue with all prescriptions - tell the doctor if you see the student closing or covering an eye when doing visual tasks or viewing through an optical device-distance or near.
Contrast Sensitivity: this clinical measurement of contrast sensitivity essentially measures how much the visual acuity drops when the student is in a room/setting with reduced illumination, using low contrast materials or has an optical system that absorbs a lot of light - like a telescope! If it is found that the student has a severe contrast problem (usually an optic nerve related diagnosis), telescope design will be important to consider for optimum functioning. If a 4X telescope is being considered, the 4X12 monocular would be the choice over a 4X10. The last number on the telescope labeling is the diameter of the front lens of the telescope and determines how much light goes into the telescope. The smaller the number, the more light loss or dimmer an image will result. So if the student has a condition that results in poor contrast for the visual system, the clinician does not want to prescribe an optical system that will make this situation worse. In some cases, I have not prescribed telescopes as the acuity will be too poor and their use will frustrate the student. If the visual acuity is 20/200, it would be expected that the acuity will get 4 times better with the use of the 4X telescope or 20/50. The student with contrast issues may only get 20/100 through the 4x10 or 20/80 through the 4x12 but enjoy 20/50 with the larger lenses of the Beecher head mounted binocular or monocular telescope design. Each subsequent system provides more light due to a larger diameter front or objective lens.
Contrast changes outside the clinic, thus when a student is having a problem with the prescribed device, check the setting to make sure that environmental contrast loss is not the issue. Often it is
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easier to change the immediate environment than to change an Rx or prescribe multiple devices.
Visual Fields - near: Many clinical reports will show the near fields with an amsler grid or other central field test as normal and most will assume from this report that this student does not have a central scotoma or field loss. This test result actually indicates the student is successfully eccentrically viewing around the central blind spot which can be detected only with more specialized field testing or instructions to the student when taking the test.
Actually is it often misunderstood that if there is a loss of acuity there has to be a correlating loss of central field or scotoma in the macular area of the retina. An exception would be the student with Albinism as the cause of the impairment. This group of students have one large central area of reduced vision - which I refer to as more a smudge for a macula which only sees 20/120 (or whatever).
The telescope has a small lens to look through so the student will need to be assessed as to the quality of fixation. A successful telescope user will have steady fixation for all tasks. If there is an unusual null point of nystagmus (position of the eyes where the nystagmus is minimal) and that is also where steady fixation occurs, bioptic telescopes may be eliminated as a beneficial prescription of choice as the telescope cannot be aligned with the position of the eye.
Nystagmus does not preclude the use of telescopes - even bioptics. (cortical visual impairment with wandering nystagmus due to very reduced acuity will be difficult to prescribe for and will need lots of practice with localizing through paper towel tubes, etc. before proceeding with low power, large field of view telescopes)
Visual Fields-periphery: A significant peripheral field loss such as might be noted with rod-cone dystrophy will result in special problems for the use of telescopes. Mainly, if the field loss is severe enough to make localization without devices difficult, telescopes need to be pursued as a prescriptive option with caution. The student must learn to localize with the small retinal visual field without devices before proceeding with telescopes. Often the student will

benefit from finding objects in the school environment and while on mobility training sessions looking through a tube of some sort that will simulate the additional field loss of a telescope. The visual skill of scanning will be of tremendous benefit to the student considering using telescopes for expanding the visual reach or visual world.
Scanning without devices requires coordinated eye movements and processing of information. When using a telescope, the eye muscles hold fixation through the telescope and scanning is accomplished with head and neck movements. Make sure the educator/doctor working with the telescope on head scanning coordinate with the mobility instructor who may be teaching scanning with eye movements.
This is just a portion of what information is needed from the clinical assessment for determining the proper telescopic prescription. This clinician will also look at other binocularity issues, glare issues, photo-phobia issues, color vision problems, specialized field losses such a hemianopsia needing further evaluation and even performance with devices at near can influence the decision on a distance telescope. So what is the rationale for prescribing that particular telescope?
Functional Optics
When deciding on a particular prescription the clinician must analyze all the clinical data as de-scribed above and then try to find a device that will address the functional problems (goals) reported by the teacher and meet the visual requirements of the measured impairment. The major functional optics issues relate to how much magnification is needed for the desired task; how much field of view is needed for this task; what are the work distance limitations of this task and does the performance of the specified task require the student to be moving about while using the device. Other issues of cost, refractive error, availability and appearances will also have to be considered but these I put into the category of psycho-social issues.
With our student, a 4x10 provides 20/40 acuity at the ten foot viewing distance in each of the two classes the student needs to see the board. It also ad‑

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dresses the student's reluctance to use the device in the classroom as I was able to attach it to a ring which hides it while in use (or at least is not as obvious). This worked great in the morning class but the after-noon class has a darker (less illuminated) room and the telescope does not provide enough light. In this case we started with the 4x10 and when the student became comfortable with this system; the TVI introduced a 4x12 system. This worked and with some difficulty the student could see the board. However, the teacher reported back this mild success and as a result, a Zeiss 4X monocular was evaluated and be-cause of the significantly better optics (and cost) the student was easily seeing the board and was able to obtain an acuity of 20/30 with this new system. In the ideal world (which did not happen in this scenario) the student would have realized how much improvement in optics the Zeiss provided and voluntarily started using it in all classes... oh well, there's always college	
The student tried using the 4x12 system at the ball game but did not find it satisfactory. The out-fielders could not be seen and the field of view was too small. In this case, the 6x16 monocular was evaluated for the ball game and other outdoor activities as reported by the student. The 6X allowed for more detail of the game to be seen but had a much smaller field of view and made it impossible to follow the action of the game.
The stronger the telescope the smaller the field of view unless the telescope is made physically larger.
In addition to the small field of view, the student complained that the arms got tired holding the telescope for an entire game. To this end, a 7X Beecher was prescribed. This is a design that is basically a pair of binoculars (or can have just one eye piece) which is strapped to the head. With this system there was now enough magnification for the greater viewing distances of a ball game, a larger field of view due to the physical size of the telescope allowing more action to be followed and reduced arm fatigue due to the device being head mounted.
Note: I could sell a dozen of these every time I take one to my ASTROS game.

Reprinted with permission from Winter 2008 Association for Education and Rehabilitation of the Blind and Visually Impaired CollAERborations Newsletter.
Now how about the mobility issue? As it turns out the student could easily use the 4X Zeiss for the travel aspects of learning to cross streets, identify signs and find addresses. The coatings on the system reduced issues of glare and allowed for the better acuity both indoors and outdoors (remember, mobility and orientation skills are needed as much indoors as outdoors). As a note, the 4x12 unit did give the student problems when going indoors and when facing shadows under trees and tall buildings.
There was a problem even with the Zeiss in the task of recognizing people's faces. The student could not get the telescope up to the eye fast enough and localize where the person was to find the face - all the while the person was moving. So this task was just blown off for the time being. Then the now 15+ year old student discovered the possibility of driving using a bioptic telescope. The acuity was appropriate and the student was an experienced and expert telescope user after a few years of use. The idea of a bioptic was not socially overwhelming as he had been publically using telescopes and has lots of parent and teacher support. It so happens that in the bioptic clinical training program the student noted how much more quickly objects could be found with the bioptic as he could localize the object with the regular glasses and then quickly move into the optics of the bioptic. Finding people, seeing their faces and recognizing them at greater distances was found to be an easy task and an additional benefit for using the bioptic.
This was just a simulated run through of just one optical device and the parameters that go into the prescribing of the telescope. The same acuity/eye/ person needed three different telescopes to improve the distance vision abilities for this student and through the interaction of the clinician, teacher and O&M Instructor, the student enjoys a significantly greater visual world and one can assume a much greater degree of independence. The success here with this young student was dependent upon the feedback the clinician received from the TVI and OM professionals and their understanding that multiple devices with differing optical properties were needed to increase the student's ability to perform varied educational and recreational distance vision tasks.