To the Editor:

I am writing regarding "When and How to Get Payment for Photoscreening" (Medicare Q&A, April 2008). The most recent policy statement "Eye Examination in Infants, Children, and Young Adults by Pediatricians"1 does not state or imply, as under the second question in your article (What are the indications for screening?) that photoscreening should be done on 3- to 4-year-old children. In fact, on page 904 it says, "Photoscreening is not a substitute for accurate visual acuity measurement but can provide significant information about the presence of sight-threatening conditions, such as strabismus, refractive errors, media opacities (cataract), and retinal abnormalities (retinoblastoma). Photoscreening techniques are still evolving." In the policy statement from the AAP2 cited in your article, there is no recommendation to use this technique, but it offers it as an alternative to screening in certain cases. On p. 525 under "Recommendations" the policy statement clarifies, "Photoscreening is an innovative tool that can facilitate vision screening in children, especially in children who are difficult to screen (i.e., infants, toddlers, and children with developmental delays)." Later the policy statement indicates, "Photoscreening needs to be studied more extensively. The AAP favors additional research of photoscreening devices and other vision screening methods in large, controlled studies to elucidate validity of results, efficacy, and cost-effectiveness for identifying amblyogenic factors in different age groups as well as subgroups of children."

Finally, the Review article should make clear that photoscreening in some children may represent an alternative to screening, not to an examination. And, I am sure Ms. McCune is not speaking for insurers when she states that exams resulting from failed photoscreenings will be paid by the carrier. If this were the case, pediatric ophthalmologists would not have been fighting for years to have "failed screening" exams of other kinds paid.

Linda M. Christmann, MD, MBA

Wilson, N.C.

1. Committee on Practice and Ambulatory Medicine, Section on Ophthalmology. American Association of Certified Orthoptists; American Association for Pediatric Ophthalmology and Strabismus; American Academy of Ophthalmology. Eye examination in infants, children, and young adults by pediatricians. Pediatrics 2003;111(4 Pt 1):902-7.

2. Committee on Practice and Ambulatory Medicine and Section on Ophthalmology; American Academy of Pediatrics.Use of photoscreening for children"s vision screening. Pediatrics 2002;109(3): 524-5.

Author Reply:

Dr. Christmann's comments on the article on photoscreening provide a more detailed, in-depth and nuanced assessment of the topic based on her thorough appreciation of the lengthy policy statements of the American Academy of Pediatrics. In the limited space available in this column, the reader can obtain a useful, if basic, appreciation of the topic and is directed to one policy statement for further information. The discussion of the indications for photoscreening in the article is carefully balanced, and not in disagreement with AAP's policies, because it provides an alternative: "a complete eye exam by an ophthalmologist skilled in the examination of children."

Dr. Christmann's other concern about reimbursement for follow-up care after failed screening is likewise a subtle issue. The second-to-last question in the article is literally true, however much physician angst is elicited by the widely misunderstood phrase "medically necessary." Clearly, there are a lot of reasons that might cause a young child to fail photoscreening, and the article does not say that all follow-up exams would be covered by insurance.

We appreciate the additional information provided by Dr. Christmann and encourage interested readers to review her citations in the original policies for more information.

Donna M. McCune, CCS-P, COE, Vice President

Kevin J. Corcoran, CPC, COE, FNAO


Corcoran Consulting Group


Enzymatic Vitreolysis a
nd Dèjá Vu

To the Editor:

The review article "Enzymatic Vitreolysis for Retinal Disorders" by George A. Williams, MD, (Retinal Insider, May 2008) is interesting indeed. The author did a nice job of summarizing recent developments in the use of enzymes to facilitate vitrectomy. These studies are a continuation of the concept that I originated over three decades ago. Back in 1976, while a resident, I began investigations into the use of purified bacterial collagenase to digest cicatricial vitreous membranes in an effort to facilitate difficult cases of vitrectomy.

The first paper appeared in 1980 in the Archives of Ophthalmology.1 In the abstract, I wrote, "The injection of purified collagenase capable of digesting vitreal scar tissue while leaving the retina undamaged could represent a new approach to vitrectomy, specifically to facilitate certain cases of membranectomy." The second paper, a time-course and toxicity study, appeared in Archives in 1983.2 The final paper, a clinical trial of six patients, appeared in Retina in 1985.3 I abandoned further work because the vitreoretinal community did not seem particularly interested in the use of enzymes more than 20 years ago.

With changing times, the old is new again. Dr. Williams and his colleagues, Jerry Sebag, MD, and Michael Trese, MD, have revived the concept of enzymatic vitrectomy albeit with different enzymes, hyalouronidase and plasmin, in lieu of collagenase. Microplasmin seems to show promise for the management of vitreoretinal traction syndromes. It would be interesting to compare its efficacy with that of purified bacterial collagenase. In a clinical trial, we found purified Clostridiopeptidase A to be effective in facilitating surgery and not toxic to the retina if incubated for only 15 minutes before vitrectomy.3 Further, intravitreal collagenase could be helpful in pediatric cases in which managing the dense regular vitreous collagen is a serious problem. I am not certain that microplasmin would be particularly effective in digesting the vitreous collagen of infants and children.

Hopefully, economic considerations will not prohibit Dr. Williams and his colleagues from performing a rigorous comparison of both microplasmin and collagenase in vitrectomy. FDA-approved injectable bacterial collagenase is available from BioSpecifics Technologies Corp. ( and is used for Dupuytren's disease, Peyronie's disease and frozen shoulder (adhesive capsulitis). The company, formerly Advance Biofactures Corp., manufactured the enzyme that I used in my work. Obtaining IRB approval to perform an off-label study of an FDA- approved drug should not be particularly difficult. I have no financial interest in Biospecifics or its products.

Louise C. Moorhead, MD


1. Moorhead LC, Redburn DA, Kirkpatrick DS, Kretzer F. Bacterial Collagenase. Proposed Adjunct to Vitrectomy with Membranectomy. Arch Ophthalmol 1980;98:1829-39.

2. Moorhead LC, Chu HH, Garcia, CA. Enzyme-Assisted Vitrectomy with Bacterial Collagenase. Time Course and Toxicity Studies. Arch Ophthalmol 1983; 101:265-74.

3. Moorhead LC and Radtke N. Enzyme-Assisted Vitrectomy with Bacterial Collagenase. Pilot Human Studies. Retina 1985;5:98-100.