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Volume 3, Number 35
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Monday, September 1, 2003
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| Prevalence of
Dry Eye Syndrome Among U.S. Women Dry eye syndrome (DES) is believed to be one of the most common ocular problems in the United States, particularly among older women, but few studies have described the magnitude of the problem in women and how this may vary with demographic characteristics. A cross-sectional prevalence survey of 39,876 U.S. women participating in the Women's Health Study reveals that DES leading to a clinical diagnosis or severe symptoms affects more than 3.2 million American middle-aged and older women, including many in their 40s and 50s. The study, the first large-scale study of DES among U.S. women, was conducted by Boston's Brigham and Women's Hospital, Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary and Department of Medicine, Harvard Medical School. Researchers surveyed 39,876 U.S. women participating in the Women's Health Study about a history of diagnosed DES and dry eye symptoms, defining DES as the presence of clinically diagnosed DES or severe symptoms (both dryness and irritation constantly or often). They calculated the age-specific prevalence of DES and adjusted the overall prevalence to the age distribution of women in the U.S. population, using logistic regression to examine associations between DES and other demographic factors. Results showed that the prevalence of DES increased with age, from 5.7 percent among women less than 50 years old to 9.8 percent among women 75 or older. The age-adjusted prevalence of DES was 7.8 percent, or 3.23 million women aged 50 or older in the United States. Compared with whites, Hispanic- and Asian-American women were more likely to report severe symptoms, but not clinically diagnosed DES. There were no significant differences by income, but more educated women were less likely to have DES. Women from the South had the highest prevalence of DES, though the magnitude of geographic differences was modest. The authors of the study point out that further research is necessary to better understand DES and its impact on public health and quality of life. |
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SOURCE: Schaumberg DA, Sullivan DA, Buring JE, Dana MR. Prevalence of dry eye syndrome among U.S. women. Amer J Ophthalmol 2003;136(2):318-26. |
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| Inhibition of
Enzyme May Lower IOP in Ocular Hypertension Patients Oral carbenoxolone (CBX), an inhibitor of the enzyme 11-beta-hydroxysteroid dehydrogenase (11-beta-HSD), may lower intraocular pressure (IOP) in patients with ocular hypertension, according to a study by Britain's University of Birmingham and Southampton General Hospital, and the Yale University School of Medicine (New Haven, CT). Data from the study suggests that this process is mediated through inhibition of type 1 11-beta-HSD (11-beta-HSD1) in the ciliary epithelium. Selective and topical inhibitors of 11-beta-HSD1 could provide a novel treatment for patients with glaucoma. IOP is maintained by a balance between aqueous humor (AH) production, which is dependent on sodium transport across a ciliary epithelial bi-layer, and drainage, predominantly through the trabecular meshwork. In peripheral epithelial tissues, sodium and water transport are regulated by corticosteroids and the 11-beta-HSD isozymes (11-beta-HSD1 activating cortisol from cortisone and 11-beta-HSD2 inactivating cortisol to cortisone). In this multi-part prospective study, researchers evaluated the expression of 11-beta-HSD1 in normal human anterior segments by in situ hybridization (ISH). Researchers performed reverse transcriptase-polymerase chain reaction (RT-PCR) for 11-beta-HSD, glucocorticoid and mineralocorticoid receptors (GR, MR) on human ciliary body tissue. They measured AH cortisol and cortisone concentrations by radioimmunoassay on specimens taken from patients with primary open-angle glaucoma (POAG) and age-matched controls. Randomized, placebo-controlled studies of healthy volunteers and patients with ocular hypertension (raised IOP but no optic neuropathy) assessed the effect of CBX on IOP. Results showed that ISH defined expression of 11-beta-HSD1 in the ciliary epithelium, while RT-PCR analysis of ciliary body tissue confirmed expression of 11-beta-HSD1, with additional GR and MR, but not 11-beta-HSD2 expression. In both POAG patients and controls, AH concentrations of cortisol exceeded those of cortisone. The CBX-treated healthy volunteers who demonstrated the largest change in urinary cortisol metabolites (indicative of 11-beta-HSD1 inhibition) had the greatest fall in IOP. Patients with ocular hypertension showed an overall reduction of IOP by 10 percent following CBX administration, compared to baseline. |
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SOURCES: Rauz S, Cheung CM, Wood PJ, et al. Inhibition of 11-Beta-hydroxysteroid dehydrogenase type 1 lowers intraocular pressure in patients with ocular hypertension. Q J Med 2003;96:481-90. |
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| Anti-TGF-beta-2
Antibody as Possible Anti-scarring Agent in Glaucoma Surgery Postoperative administration of transforming growth factor-beta-2 (CAT-152, lerdelimumab) in glaucoma filtration surgery may significantly improve surgical outcome, reduce subconjunctival scarring and minimize the risk of corneal side effects compared with that of the anti-scarring agent 5-fluorouracil (5-FU), according to results of an animal study by London's Moorfields Eye Hospital. The findings suggest that CAT-152 may offer therapeutic benefit as a postoperative agent to prevent subconjunctival scarring after glaucoma filtration surgery. Postoperative subconjunctival wound healing remains the most common cause of late bleb failure after glaucoma filtration surgery. In a randomized, controlled, masked-observer study, researchers randomly allocated 48 rabbits after modified glaucoma surgery to receive a postoperative course of seven subconjunctival injections of CAT-152 (1 mg/mL), 5-FU (50 mg/mL) or no treatment. They assessed bleb characteristics, the presence of subconjunctival drainage and local reaction to treatment. Animals were sacrificed on Days 10, 21 and 30, and researchers performed immunohistochemistry, histologic staining and electron microscopy to demonstrate the mechanism of CAT-152-mediated effects on the extracellular matrix. CAT-152 significantly improved surgical outcome and reduced subconjunctival collagen deposition compared with 5-FU and control. Median bleb survival was increased in the CAT-152 group (23.5 days) compared with the 5-FU (20 days) and control (16 days) treatment groups. CAT-152 treatment improved bleb morphology and was well tolerated, while 5-FU prolonged the duration of corneal epitheliopathy. |
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SOURCE: Mead AL, Wong TTL, Cordeiro MF. Evaluation of anti-TGF-beta-2 antibody as a new postoperative anti-scarring agent in glaucoma surgery. Invest Ophthalmol Vis Sci 2003;44(8):3394-401. |
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| Peripheral Refraction
and Retinal Steepness in Children Peripheral refraction seems to be correlated with retinal steepness, and previously observed variability in peripheral refraction chiefly reflects variability in retinal steepness, according to a recent study. Results suggest that if peripheral refraction represents a determining parameter in the control of eye growth, the precise measurement of retinal steepness might be used not only to improve estimates of myopic progression, but also to identify children who are at high risk of developing myopia. Considerable evidence suggests that both axial and peripheral refraction play important roles in eye growth control. The large variability in peripheral refraction seen in adults and children indicates that the peripheral retina is exposed to a wide range of refractive errors. The current lack of appropriate measurement techniques has hampered the determination of whether variability in peripheral refraction between individuals can be correlated with variability in retinal steepness. Researchers in this study developed an Optical Low Coherence Reflectometer (OLCR) to determine retinal steepness. They assessed retinal steepness in the right eyes of 63 children 7 to 15 years old by measuring eye length (EL) and spherical equivalent refraction (SER) axially and at 15 degrees temporally, nasally, inferiorly and superiorly with OLCR and Binocular Auto-Refractometry, respectively, during cycloplegia. At each peripheral location, they compared relative peripheral EL and SER (that is, the difference between peripheral and axial readings) between myopic, emmetropic and hyperopic eyes. They also analyzed the correlation between relative peripheral EL and SER. Although the standard deviations were large, researchers observed significant differences in relative peripheral EL and SER between refractive groups as well as a significant correlation between relative peripheral EL and SER at several of the assessed locations. The authors believe that the findings may lead to specialized clinical/optical treatments, such as the correction of axial and peripheral refractive errors, which are more effective than current treatments in individuals at risk of myopia development or progression. |
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SOURCE: Schmid GF. Variability of retinal steepness at the posterior pole in children 7-15 years of age. Curr Eye Res 2003;27(1):61-8. |
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BRIEFLY
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FDA
GIVES PRE-MARKET APPROVAL TO PHAKIC IOL.
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