Vision Rehabilitation and Intra-Ocular Telescopes – shortened
As ophthalmologists involved in vision rehabilitation we feel compelled to let our voice be heard
on the issue of intra-ocular telescopes. Our reaction was triggered by a recent paper1, but is
directed at a growing list of related papers. Our intention is not to stifle innovation, but to ask for
adequate, comparative studies.
Macular degeneration is a significant and growing problem across the world. We are frustrated
that we cannot change the condition of the retina. It is understandable that surgeons seek
remediation through surgery. It is encouraging that surgical techniques have progressed to a
point where complex devices can be implanted without major additional risks. Yet, since all
surgery carries risks, more complex surgery is bound to carry more risks.
All papers on this subject report that the patients saw better and felt better after surgery than
they did before. However, they fail to separate the factors that contribute to this improvement:
Removal of a cataractous lens.
Insertion of a telescopic device.
Rehabilitation training following surgery.
By not separating these factors, it is impossible to estimate how much improvement can be
attributed to each of them.
The contribution of lens extraction cannot be known precisely, but clinicians can estimate it from
ophthalmoscopy or by PAM and interferometry.
The theoretical improvement due to the telescopic system can be calculated. It would be
worthwhile to also calculate how off-axis placement or tilt can reduce this. In the latest paper,
the theoretical magnification is given as 1.3x, equivalent to about one line (26%) on an ETDRS
chart. In cases where fundus photography is possible, the minification of the postoperative
image (the camera is looking through a reverse Galilean telescope) is an objective measure of
the actual magnification achieved. We are not aware that studies have reported this.
As Vision Rehabilitation professionals, we know first hand how much vision rehabilitation can
improve the patient’s performance of daily living skills, even with a defective macula2-4.
Unfortunately, many of our colleagues are not convinced, because letter chart testing does not
adequately measure these results.
Vision rehabilitation has three objectives.
(1) Improving the optical image. This can be achieved with various magnification devices, from
a low-tech hand magnifier to a high-tech video-magnifier, with improved illumination, use of
filters, etc. Intra-ocular telescopes address this magnification aspect, but they reduce the field
of view, which can be a risk factor for falls5.
(2) Improving the use of the eccentric Preferred Retinal Locus (PRL) or pseudo-fovea. Training
can improve search and fixation strategies as well as hand-eye coordination. In our offices we
see on a daily basis results such as improved reading speed, improved reading distance and
improved reading endurance, as reported in the latest paper. These effects often are greater
than the theoretical 1-line improvement provided by the telescope in the latest paper.
(3) Improving the patient’s safety, participation and well-being and the performance of Activities
of Daily Living (ADLs) through attention to non-visual cues, through adapted aids, through
environmental modifications and through improving the awareness of the patient’s condition
among family members and others.
We commend the authors for including a significant vision rehabilitation component. However,
since this training was done after surgery, its effect could not be separated from the other
In this age of evidence-based medicine, patients and the profession deserve sound insight into
the relative effects of various interventions. We therefore recommend that any study about the
implantation of telescopic devices contain the following.
As a minimum, estimates of the relative contributions of the three interventions.
Preferably, a comparison of matched groups: surgery vs. structured vision rehabilitation.
The gold standard would be a true Randomized Clinical Trial.
When such comparative studies are done, the benefits of intra-ocular telescopic devices can be
properly separated from the improvements that can be achieved with vision rehabilitation
training alone. However, unless journals and others insist that these comparisons be made, we
will never have definitive proof of their relative strengths.
We urge you and other journal editors to apply these suggestions as review criteria for any
paper that is sent for your review.
Original = 850 words Shortened = 682 700 = limit for letters to the editor.
* August Colenbrander, MD Smith-Kettlewell Eye Research Institute, San Francisco, CA
* Donald C. Fletcher, MD California Pacific Medical Center, San Francisco, CA
Judith A. Bennington, MDAshland, WI
A. Jan Berlin, MDPortland, ME
* Ronald J. Cole, MDSacramento, CA
* Robert M. Christiansen, MD University of Utah, Salt Lake City, UT
Eleanor Faye, MD Lighthouse International, New York, NY
* Joseph Fontenot, MDCommunity Services for Vision Rehabilitation, Daphne, AL
Bert M. Glaser, MDNational Retina Institute, Birmingham, AL
* Paul Homer, MD,Boca Raton FL
* Mary Lou Jackson, MDMassachusetts Eye and Ear Infirmary, Boston, MA
Mary G. Lawrence, MD, MPH University of Minnesota, Minneapolis, MN
* Samuel N. Markowitz, MD University of Toronto, Toronto, Canada
* Lylas Mogk, MD Henry Ford Medical Center, Detroit, MI
* Rebecca Morgan, MD University of Oklahoma, Oklahoma City, OK
* Nelson Sabates, MDUniversity of Missouri, Kansas City, MO
Sheila Santos-Jimenez, MD St. Luke's Medical Center, Philippines
* John Shepherd, MDUniversity of Nebraska Medical Center; Omaha, NE
implant for visual rehabilitation of patients with macular disease. Ophthalmology. 114(5):860-5, 2007
Orzalesi N, Pierrottet CO, Zenoni S, Savaresi C. The IOL-Vip System: a double intraocular lens
Measuring Outcomes of Vision Rehabilitation with the Veterans Affairs Low Vision Visual Functioning
Questionnaire. IOVS, August 2006, Vol. 47, No. 8
Stelmack JA, Szlyk JP, Stelmack TR, Demers-Turco P, Williams TR, Moran D’A, Massof RW.
inpatient vision rehabilitation program. Arch Phys Med Rehabil 2007;88:691-5.
Stelmack JA, Moran D’A, Dean D, Massof RW. Short- and long-term effects of an intensive
Journal of the Society for Clinical Trials – in press.
The Veterans’ Affairs Low Vision Intervention Trial: Design and Methodology. Clinical Trials:
Adults: The Salisbury Eye Evaluation ;; IOVS, 2007;48:4445-4450.
Freeman EE, Muñoz B, Rubin G, West SK. Visual Field Loss Increases the Risk of Falls in Older
5 most relevant references = limit for “Ophthalmology”.