Volume 4, Number 48
Monday, November 29, 2004



In this issue: (click heading to view article)
Macular Pigment Density and Aging in Normal, Cataract and AMD Elderly
Pirenzepine Ophthalmic Gel in Children with Myopia
A Novel Molecular Target for Retinoblastoma Therapy
Iridectomy Histopathologic Features of Latanoprost- and Non-Latanoprost-Treated Patients
Briefly











Macular Pigment Density and Aging in Normal, Cataract and AMD Elderly

Increasing evidence has linked retinal lutein and zeaxanthin (termed macular pigment, or MP) to the risk of age-related macular degeneration (AMD). Currently, however, studies differ regarding the question of whether MP declines with age, or age has an effect in patient populations being assessed. A prospective, observational cross-sectional study by Indiana’s Midwest Eye Institute assessed MP across the lifespan with an emphasis on assessing MP in a cross-section of elderly, including those with lenticular or AMD, or both.

Three hundred ninety subjects, 22 with cataracts and 59 with AMD, were tested in Indianapolis, IN. Investigators measured MP density with a one-degree diameter test field at 460 nm using a psychophysical method based on heterochromatic flicker photometry. Results showed that MP does not appear to change as a function of age when examining subjects across the lifespan (from 18 to 88 years). They showed a slight tendency for MP to decline when only the elderly subjects were considered, but this trend was not significant for any of the groups considered (normal, cataractous or AMD).

The authors of the study concluded that MP does not change significantly with age, even when elderly subjects with cataracts and AMD are considered. When heterochromatic flicker photometry is employed, elderly subjects display a full range of MP density similar to that of young subjects.

SOURCE: Ciulla TA, Hammond BR Jr. Macular pigment density and aging, assessed in the normal elderly and those with cataracts and age-related macular degeneration. Am J Ophthalmol 2004;138(4):582-7. 		Table of Contents











Pirenzepine Ophthalmic Gel in Children with Myopia

The relatively selective M(1) antagonist pirenzepine hydrochloride is effective and relatively safe in slowing the progression of myopia in school-aged children during a one-year treatment period, according to researchers at the University of Oklahoma and the Dean A. McGee Eye Institute, Oklahoma City.

Investigators conducted a parallel-group, placebo-controlled double-masked study of healthy children aged 8 to 12 years in 13 U.S. academic clinics and private practices. All children had a spherical equivalent of -0.75D to -4.00D and astigmatism of 1.00D or less. Patients underwent a baseline complete eye examination and regular examinations during a one-year period; they were randomized in a 2:1 ratio to receive 2% pirenzepine ophthalmic gel or a placebo control twice daily for a year.

At study entry, the spherical equivalent was mean +/- SD -2.098D +/- 0.903D for the pirenzepine group (117 children) and -1.933D +/- 0.825D for the placebo group (57 children). At one year, results showed a mean increase in myopia of 0.26D in the pirenzepine group vs. 0.53D in the placebo group. No patients in the placebo group and 13 (11 percent) of 117 patients in the pirenzepine group discontinued participation in the study because of adverse effects (five children, or four percent, of 117 due to excessive antimuscarinic effects).

SOURCE: Siatkowski RM, Cotter S, Miller JM, et al. Safety and efficacy of 2% pirenzepine ophthalmic gel in children with myopia: a one-year, multicenter, double-masked, placebo-controlled parallel study. Arch Ophthalmol 2004;122(11):1667-74.		 Table of Contents











A Novel Molecular Target for Retinoblastoma Therapy

Epithelial cell adhesion molecules (EpCAMs) are vastly expressed in retinoblastoma and point to their use as a target for retinoblastoma therapy in the future, according to investigators in Chennai, India, and Providence, RI.

The researchers first determined whether EpCAM is expressed in retinoblastoma and then whether EpCAM reactivity correlates with tumor aggressiveness. They evaluated EpCAM reactivity by immunohistochemistry in 43 retinoblastoma specimens from 43 patients, using the monoclonal antibody GA733. The tumors were divided into two groups: 20 had no invasion of the choroid and optic nerve (Group A) and 23 had invasion of the choroid, optic nerve and orbit (Group B). EpCAM reactivity was correlated with invasion and differentiation of the tumors.

Among the 43 tumors, EpCAM reactivity was observed in 100 percent of the tumors. EpCAM reactivity was significantly higher in the invasive than the noninvasive tumors and in poorly differentiated than in well-differentiated tumors. Non-neoplastic retina also expressed EpCAM.

SOURCE: Krishnakumar S, Mohan A, Mallikarjuna K, et al. EpCAM expression in retinoblastoma: a novel molecular target for therapy. Invest Ophthalmol Vis Sci 2004;45(12):4247-50. 		Table of Contents










Iridectomy Histopathologic Features of Latanoprost- and Non-Latanoprost-Treated Patients

Researchers at the University of Wisconsin recently conducted a study examining the histopathologic features of iridectomy specimens from patients undergoing glaucoma surgery, and compared histologic abnormalities in patients with a history of latanoprost therapy with those who had no history of prostaglandin therapy (controls). The results supported previous studies indicating that latanoprost-induced eye color changes are the result of an increased amount of melanin within the iris stromal melanocytes.

Iridectomy specimens and patient history forms were received from 449 patients with a history of latanoprost treatment and 142 patients who had no history of treatment with latanoprost or other prostaglandin analogues. No evidence of malignant or premalignant changes was found. The specimens were submitted to the central Latanoprost Pathology Center at the university’s medical school. These were independently examined by three ophthalmic pathologists in a masked fashion. The pathologists evaluated specimens for malignant, pre-malignant and other changes, including differences in pigmentation levels, degrees of cellularity, inflammation, vascular abnormalities and changes in the iris pigment epithelium.

In latanoprost-treated irides, the prevalence of iris freckles was higher than in control irides, as was the combined number of stromal fibroblasts and melanocytes. The increased numbers of freckles may be a focal manifestation of the effect of latanoprost. In a subgroup of specimens received through June 2002, investigators found no significant difference in mean melanocyte counts obtained by immunohistochemical staining techniques between the latanoprost-treated and control groups.

SOURCE: Albert DM, Gangnon RE, Zimbric ML, et al. A study of iridectomy histopathologic features of latanoprost- and non-latanoprost-treated patients. Arch Ophthalmol 2004;122(11):1680-5. 		Table of Contents







BRIEFLY
  • HYDROGEL PUNCTUM PLUG APPROVED BY FDA. Oasis Medical has received FDA approval of its new Form Fit long-term intracanalicular plug. The Form Fit is a one-size plug made of a hydrogel material that conforms to fit all patients. Upon contacting tear film, it expands into a soft, pliable, gelatinous material; in about 10 minutes it becomes completely hydrated and fills the vertical canalicular cavity. It has no anchor or cap and can be easily removed by flushing saline solution through the punctal opening. Form Fit comes pre-loaded on an inserter. The dry plug measures 3.0 mm long and 0.3 mm in diameter; it expands to 20 times the volume of its original size. Form Fit punctal plugs are available in boxes of 10 (five pairs per box). For more information, call 800-528-9786.
  • ALLERGAN SPONSORS NATIONAL PROGRAM ON GLAUCOMA EVALUATION. Allergan, Inc., is sponsoring a national program called FORGE--"Focusing Ophthalmology on Reframing Glaucoma Evaluation"--developed by leaders in ophthalmology, including George A. Cioffi, MD (Devers Eye Institute); Anne L. Coleman, MD, PhD (David Geffen School of Medicine at UCLA); Ronald L. Gross, MD (Baylor College of Medicine); Jeffrey M Liebmann, MD (New York University School of Medicine); and Robert N. Weinreb, MD (University of California, San Diego). The focus of the FORGE program is to reframe how ophthalmologists assess their patients’ disease severity by focusing on the evaluation of the optic nerve. The goal is to achieve greater accuracy in assessment of severity, which leads to better disease management at earlier stages. The interactive program presents a systematic review of the latest data and provides a practical approach for treating glaucoma patients. For more information about FORGE, e-mail [email protected].
  • VISIJET’S EPILIFT LASIK PROCEDURE DEBUTS. VisiJet, Inc., has introduced the recently FDA-approved EpiLift System, a refractive surgery technique that enables ophthalmologists to perform Epi-LASIK surgery. Unlike LASIK and PRK, the procedure does not require the surgeon to cut the cornea or apply alcohol. VisiJet acquired the worldwide distribution rights for the EpiLift System from Gebauer Medizintechnik GmbH of Germany in May 2004, received FDA approval in September 2004, and is now marketing and selling it in the United States and internationally. In addition to EpiLift, the company is developing HydroKeratome and Pulsatome using its proprietary, patented waterjet technology. For more information, call 949-450-1660.

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