Eastern Mediterranean Council of Optometry Marrakesh, Morocco 2018

On September 21 and 22, 2018, I was an invited speaker at the 2nd Annual Eastern Mediterranean Council of Optometry (EMCO) meeting in Marrakesh, Morocco. While not quite located on the eastern Mediterranean, their first meeting in Beirut, Lebanon in 2016 certainly was!  I want to express my appreciation to the EMCO Scientific committee, Dr. Hassan Awada, Dr. Yazan Gamoh, and Dr. Liana Al-Labadi for their invitation.

I met optometrists and optometry students from all over the Middle East, northern Africa, India, Nepal and Bhutan. Speakers ranged from far and wide, including the US, Canada, UK, France, Australia, Sudan, South Africa, Lebanon, Palestine and Jordan. Topics ranged from myopia control (with Naidoo Kovin, CEO of the Brien Holden Vision Institute), scleral contact lenses, amblyopia, ortho-keratology, pediatric eyecare, and for me, of course, low vision.  Co-sponsored by the Moroccan Council of Optometry and the World Congress of Optometry (WCO), the meeting attracted several hundred attendees.

I was asked to present three COPE approved courses—the first on treating distance vision loss, a second on understanding and treating hemianopic and tunnel vision visual field loss, and lastly a bioptic prescribing and fitting workshop. The 2-hour workshop, limited to 12 attendees was filled with energetic, enthusiastic (and young!) optometrists. We discussed how to identify promising candidates, determine the appropriate prescription, establishing a prognosis, and especially the nuts and bolts of fitting the telescopes.  Attendees played the roles of both patients and doctors and took turns fitting the Ocutech bioptics on each other.  It didn’t take long for them to see how easy it is!  We also demonstrated the new Ocutech Falcon Autofocus bioptic, which was a highlight and huge success!  Since many spoke only French and Arabic, I was ably translated and assisted by Dr. Liana Al-Labadi, a 2009 graduate of the OSU School of Optometry, who now practices in Palestine.

Dr. Greene with Hamid Nafis, chairman of EMCO 2018.
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Notes about Keplerian ‘expanded field’ telescopes.

An invited blog contribution by Alan Johnston, OD, FAAO

Dr. Alan Johnston is an Australian optometrist and a 1985 low vision diplomate of the American Academy of Optometry.  He practices in Melbourne, Australia.

Some optical facts:

Keplerian telescopes provide additional benefits for bioptic use over Galilean types.  Originally designed for astronomical use, Keplerians provide a wider field of view than Galileans of comparable magnification (Mx). 

Keplerian telescopes for astronomy provide a reversed and upside-down image, but for patients the image must be upright and translated left-to-right.  Image inversion/translation was achieved at first using Porro prisms, named after their Italian inventor.  Porro prism binoculars have the characteristic, dog-leg shape where the front lenses are more widely spaced than the lenses close to the eye.  A more compact prism design is the lightweight Pechan-Schmidt combination, known generally as roof prisms, which have become popular in higher quality binoculars.  Prisms offer the additional benefit of ‘folding’ the optical path hence shortening the physical length of the telescope.   

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Is the ORCAM really an “Artificial Vision Device”?

Referencing article: http://iovs.arvojournals.org/article.aspx?articleid=2335212

by Henry A Greene, OD, FAAO

A paper titled The Impact of a Novel Artificial Vision Device (OrCam) on the Quality of Life of Patients with End-Stage Glaucoma by Michael Waisbourd, et.al. appeared in Investigative Ophthalmology & Visual Science in June 2015, Vol. 56 (see link to paper above). New technology to aid the visually impaired is always welcome and serves also to move the field forward, however we need to be careful to describe these products in a way that honestly represents their function and the benefit they provide.

photo of person wearing orcam
Photo from Orcam.com

The ORCAM, a portable head-born text-to-audio device that can be attached to eyeglasses, is a novel and potentially very helpful device to enable the visually impaired (as well as others) to access text material such as on signs, packaging, publications and also to aid in recognize faces and provide their names to the user via a bone conduction speaker.

Accessing printed material is often the first and major complaint and functional concern of individuals who are visually impaired and the ORCAM has the potential to effectively address that need.

However, calling the ORCAM an “Artificial Vision Device” misrepresents the innovative technology that it provides as it offers no visual enhancement, solely an audio presentation of items scanned by the device. While it may read text and recognize and name your friends, family and other items of interest, it does not allow the user to actually see them. So, while the device may well be of value to the user, it does not provide vision of any kind, and hence the “Artificial Vision” nomenclature is misleading both in terms of what it does and also what a potential user would expect it to provide.

I would not presume to have the right to suggest an alternate descriptive for the Orcam, but do hope that others might.

A discussion about refraction for visually impaired individuals.

I’m often asked how I manage eyeglass prescriptions for my low vision patients, so I thought I’d spend a little time exploring this issue. I’ve presented this discussion in many talks I’ve given, but thought perhaps it was time to put it in writing.

Hope you’ll find this helpful.

Henry Greene

eyeglasses in front of an eye chart

Refraction, of course, is the optometrist’s mainstay. If we can make a sufficient improvement in acuity by refraction, (usually a two-line improvement is required for the patient to experience a functional gain), than obviously that would be our first and most convenient option. A brief retinoscopy through the current eyeglasses (if any) can be valuable to see how close to neutral the reflex is as well as its quality. (Only perform retinoscopy briefly. If you spend too much time you’ll bleach the retina, which will often delay and undermine your exam.) If the reflex is dull due to media issues, consider therapeutic options that might improve it. No amount of lens power will impact acuity if there are significant media opacities. If the patient is post cataract surgery with IOLs, it is unlikely that they will have a significant refractive error. If they do, there is often an astigmatic component.

Generally, by the time a patient gets to a low vision practitioner, if a new refraction would have been of value, it would have already been prescribed. Remember, small changes don’t make big differences! If a patient sees 20/400 a half diopter or 10-degree axis change will be of little value. Changes in refraction will have more potential impact when acuity is 20/80 or better as a modest change might yield 20/60 and that can be helpful. Improving acuity from 20/400 to 20/300 is unlikely to impact the patient’s functional life. So, as a result I will spend more time refining a refraction when acuity is 20/80 or better. I find keratometry can be a very valuable tool. The character of the mires as well as cylinder can often be missed and this data can sometimes make a difference in better-seeing individuals.

I always use a trial frame; I find it more reliable and it allows for a better rapport with the patient. Trial frames are especially important with high cylinders, because it lets the patient maintain their normal posture rather than an unnatural one induced by the phoropter, which can avoid a host of cylinder axis hassles.

Remember to make a sufficient enough power change for the patient to notice. If they can’t notice a half-diopter change, try one diopter changes. There’s no use in making changes smaller than what the patient can reliably respond to- everyone will just get frustrated and you’ll not make any progress.

Remember also that the high-contrast acuity chart is a poor determiner of functional value. After I’ve determined the best refraction, I find it helpful for the patient to look at a low contrast target such someone’s face at the furthest distance that they can normally see it. If the patient can notice a difference, then the Rx change is likely to be of functional value. If they don’t notice a difference than I don’t pursue it further. Keep in mind also that acuity will fluctuate as fixation varies. Don’t let a fleeting acuity improvement fool you into thinking it’s the refraction change that’s helping—it’s more likely a PRL issue. The prescription change has to be enough to make a “real” difference! Remember that if the patient can “almost see something” they still can’t see it!

When refraction is the best you can achieve and acuity remains inadequate for the patient’s goals, than there’s only one option left to further enhance distance vision- make it bigger! And, of course, we have only two ways to do that—walk up close enough to see it, or, make it closer optically (with telescopes!).

The In’s and Out’s of Telescopes for Low Vision: Achieving a Balance between Acuity and Field of View in Prescribing.

As we know, patients often explain that they cannot see far enough away to perform whatever activity they have in mind. They must move closer in order to see it adequately—which they may or may not be able to do, or feel comfortable doing! Patients with 20/40 vision, however, rarely complain of difficulty seeing. Individuals are licensed to drive without restrictions with 20/40 acuity, and children are unencumbered in the classroom with that level of vision.

It is reasonable to assume then, that if we can provide 20/40 acuity through the telescope, most patients should be reasonably satisfied with the functional benefit it provides. So, if the goal is 20/40, a 2x device should be adequate for an individual with 20/80 acuity, 4x for 20/160, and 6x for 20/320. If we prescribe higher magnification to achieve better acuity it will be at the expense of a narrower field of view, which is the major complaint of telescope users. Also, the higher the magnification, the greater the image motion due to head movement that may actually undermine the benefit of the higher power device.

Clinically we find that users have increasing difficulty finding what they’re looking for when fields of view become narrower than about 10 degrees. So we always need to balance adequate acuity with field of view. Personally, I prescribe Galilean telescopes for powers 2.2x and lower, and Keplerian at 3x and higher.

I have found that patients respond most well to telescopic low vision aids when their acuities are 20/200 (6/60) or better. Keplerian telescopes in 4x and 5x can readily provide 20/40 and the telescope fields of view are greater than 10 degrees. I like to tell my ophthalmology colleagues that their goal is to keep their patient’s vision 20/200 or better. Now with the wonderful success of Anti VegF treatments, many patients have acuity much better than that, making their response to low vision aids even more robust.

Bioptics: Gold Standard for Low Vision Patients (Part 2)

femaile doctor talking with patient

Why Simply Prescribing a Reading Device May Be a Shortsighted Solution for Low Vision Patients, Part 2

It’s understandable why low vision prescribers quickly turn to magnifiers for their low vision patients. Reading is typically the first activity that a patient hopes to improve so many low vision product conversations begin on the topic. Additionally, magnifiers are familiar to most patients and are easy for prescribers to demonstrate, as lighting can be controlled and the print can be shown in high contrast.

New digital technology solutions exist to help low vision patients access printed material like electronic magnifiers, text to speech converters (even available on smart phones), ebooks, radio reading services, and recorded books.  However, improving access to print does not address a major component of our day-to- day lives—seeing at a distance.  Distance vision is an important social sense; allowing us to make eye contact, read body language and subsequently, feel more connected and engaged to loved ones and the world around us. Loss of distance vision directly impacts quality of life in ways that reading vision does not. While there are a myriad of ways to access the printed word, no one can see the world around you…for you.

While reading is certainly important, many low vision patients don’t realize that they will benefit from a distance low vision device that can help them in social situations as well.

The Bottom Line: Loss of distance vision usually impacts independence and self-worth much more than the inability to read. It is important for prescribers to educate patients on all low vision device options so they can work in harmony to find the solutions to address the full range of activities they face in their every day life.

Bioptics: Gold Standard for Low Vision Patients (Part 1)

man wearing bioptics and enjoying time with granddaughter

Why Simply Prescribing a Reading Device May Be a Shortsighted Solution for Low Vision Patients

The major goal in low vision care for central vision loss is to magnify images sufficiently to make them easily visible by the patient.

While the majority of our visually impaired patients seek to improve their ability to read, studies show that nearly 65% of patients also seek better distance vision.

Continue reading “Bioptics: Gold Standard for Low Vision Patients (Part 1)”

Understanding “Galilean” vs. “Keplerian” and “Wide Angle” vs. “Expanded Field” telescopes

I thought that this discussion might shed some light on how bioptic telescopes are named and what the names represent.

As is well known, bioptic telescopes are available in two optical designs—Galilean and Keplerian. Each has its distinct characteristics and attributes. We prescribe them, of course, to support our patients’ range of distance-seeing needs and activities, not just for bioptic driving.

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