Volume 3, Number 12

Monday, March 24, 2003

In this issue: (click heading to view article)
		Tear Evaporimetry System to Detect Obstructive Meibomian Gland Dysfunction
		Visual Performance and Morphologic Alterations Five Years After PRK
		Er:YAG Laser Goniopuncture vs. Trabeculectomy as Cataract Surgery Adjunct
		Retinochoroidal Collateral Veins May Protect Against Neovascularization after CRVO
		Variability of Fasting Plasma Glucose: A Risk Factor for Diabetic Retinopathy?
		Briefly

	Click here for more information.

Tear Evaporimetry System to Detect Obstructive Meibomian Gland Dysfunction A newly developed tear evaporimetry system that detects real-time changes in tear evaporation rates also helps differentiate patients with obstructive meibomian gland dysfunction (MGD) from normal subjects, according to researchers at the Department of Ophthalmology, Tokyo Dental College, Japan. In a prospective case-control study of 38 eyes of 22 normal subjects and 32 eyes of 21 patients with obstructive MGD, researchers used a ventilated chamber system with a high-sensitivity microbalance sensor to evaluate tear evaporation. They measured tear evaporation rates and "flip heights" — dynamic changes in evaporation rates in response to blinking — and compared them in both groups of patients. The relationship between tear evaporation rates and flip heights to meibomian gland orifice obstruction was also analyzed. Results showed changes in tear evaporation rates produced by blinking. The tear evaporation rates and flip heights in the MGD group were significantly higher than in normal subjects. Correlations between both tear evaporation rates and flip heights to the meibomian gland orifice obstruction score were statistically significant. Researchers believe that the higher evaporation rates and higher flip heights measured with the system reflect unstable tear evaporation, and they may well indicate unstable tear film in patients with obstructive MGD with abnormal evaporative tear loss.

SOURCE: Goto E, Endo K, Suzuki A, et al. Tear evaporation dynamics in normal subjects and subjects with obstructive meibomian gland dysfunction. Invest Ophthalmol Vis Sci 2003;44(2):533-9.

Visual Performance and Morphologic Alterations Five Years After PRK In vivo confocal microscopy demonstrates the presence of morphologic alterations even 5 years after photorefractive keratectomy (PRK), but the alterations are overcome by cellular and neural recovery and do not interfere with visual performance, according to a study by Finland’s University of Helsinki Department of Ophthalmology. Researchers examined 14 eyes of 14 patients aged 27 to 53, five years after they underwent 6-mm diameter PRK for low to moderate myopia (spherical equivalent [SE] -2.5 to -8.0D). Nine healthy individuals were control subjects. Researchers performed standard biomicroscopy, manifest refraction and visual acuity tests and examined the morphology of all corneas by in vivo confocal microscope. They obtained thicknesses of the epithelium and stroma, as well as the density of corneal opacity (haze), from digital image analysis of the confocal microscopy through-focusing (CMTF) scans. Results from confocal microscopy revealed increased reflectivity in the subepithelial extracellular matrix, keratocyte nuclei and processes in all PRK patients. The mean objective haze estimate was 166.7 U in control corneas compared with a mean of 225.9 U in post-PRK corneas. The density of the subbasal nerve fiber bundles in post-PRK corneas was not significantly lowered from that in control subjects. Bowman"s layer was undetectable in all post-PRK corneas. Clinically, slitlamp-observed trace of haze in four corneas correlated positively with the ablation depth and the thickness of the haze area in the confocal microscope.

SOURCES: Moilanen JA, Vesaluoma MH, Muller LJ, Tervo TM. Long-term corneal morphology after PRK by in vivo confocal microscopy. Invest Ophthalmol Vis Sci 2003;44(3):1064-9.

Er:YAG Laser Goniopuncture vs. Trabeculectomy as Cataract Surgery Adjunct Combined erbium:YAG (Er:YAG) goniopuncture and cataract surgery lowers intraocular pressure (IOP) to an extent comparable to combined trabeculectomy and cataract surgery but has fewer postoperative complications, according to a study by Albert-Ludwigs University in Freiburg, Germany. Researchers aimed to compare the efficacy of endoscopic Er:YAG laser goniopuncture to trabeculectomy in glaucoma treatment, considering both methods as adjuncts to cataract surgery. Fifty-nine eyes of 59 glaucoma patients with coexistent cataract were treated by phacoemulsification and endoscopic Er:YAG goniopuncture in a combined fashion. The primary study endpoints were IOP, number of antiglaucomatous drugs, postoperative complications, hospitalization time and visual acuity at 1 year after surgery. Twenty-four eyes have thus far finished the 1-year follow-up. This prospective treatment arm was compared to a retrospective inclusion-matched control group treated by trabeculectomy and cataract surgery in a single procedure. In the laser-treated group, the mean IOP dropped by 30 percent from 23.4 +/- 3.7 mmHg to 16.3 +/- 6 mmHg after 12 months. Without reoperation, treatment was successful in 71 percent of these eyes. In the control group, the IOP decreased by 33.5 percent from 22.7+/- 3.3 mmHg to 15.1 +/- 3.8 mmHg. The success rate without reoperation was 46 percent. The number of antiglaucomatous drugs required decreased from 1.48 +/- 0.95 to 0.48 +/- 0.7 in the laser-treated group and from 2.0 +/- 0.9 to 0.39 +/- 0.6 in the control group. Postoperative complications occurred more frequently and postoperative visual acuity was lower in the control group; hospitalization time was shorter in the laser group. Due to fewer postoperative complications, researchers believe that Er:YAG goniopuncture seems to be superior to standard fistulation surgery as the primary approach within the first year.

SOURCE: Feltgen N, Mueller H, Ott B, et al. Endoscopically controlled erbium:YAG goniopuncture versus trabeculectomy: effect on intraocular pressure in combination with cataract surgery. Graefes Arch Clin Exp Ophthalmol 2003;241(2):94-100.

	Click here for more information about LUMIGAN®.

Retinochoroidal Collateral Veins May Protect Against Neovascularization after CRVO Clinicians at Retina Consultants of Alabama in Birmingham report that retinochoroidal collateral veins are negatively associated with anterior segment neovascularization (ASN) following central retinal vein occlusion (CRVO), and that they may function protectively against such an outcome. In a case-control retrospective medical record review of patients with CRVO, clinicians identified 107 patients with CRVO, of whom 34 had developed ASN. After applying exclusion criteria, they selected a case group and an age-, sex- and visual acuity-matched control group. They analyzed the groups for the presence or absence of RCVs and noted the time course involved in their development. One (5.4 percent) of 19 individuals who developed ASN did so in the presence of RCVs. In contrast, 11 (57.9 percent) of 19 individuals in the control group developed RCVs. Statistical analysis revealed that patients who developed ASN were roughly 25 times less likely to have had RCVs than individuals who never developed ASN (odds ratio = 24.74).

SOURCE: Fuller JJ, Mason JO 3rd, White MF Jr, et al. Retinochoroidal collateral veins protect against anterior segment neovascularization after central retinal vein occlusion. Arch Ophthalmol 2003;121(3):332-6.

Variability of Fasting Plasma Glucose: A Risk Factor for Diabetic Retinopathy? Fasting plasma glucose (FPG) variability may be considered a risk factor for retinopathy in Type 2 diabetic patients, according to a cohort study by Spain’s Alcaniz Hospital. In the study, 130 Type 2 diabetic patients without retinopathy were recruited from June 1994 to June 1998. The fundus was reexamined between November 2000 and June 2001, with a mean follow-up period of 5.2 years. Clinicians measured fasting plasma glucose (FPG) variability by its variation coefficient (VC). They used stratified and multivariate models to estimate the effect of FPG variability and mean glycated hemoglobin (HbA1c) during follow-up on cumulative incidence of retinopathy. The cumulative incidence of retinopathy was 36.2 percent and increased all along the quartiles of FPG variability. After adjustment for confounders, time sequence, dosage response gradient and biological plausibility, a statistically significant association existed between FPG variability and the onset of retinopathy in Type 2 diabetic patients.

SOURCE: Gimeno-Orna JA, Castro-Alonso FJ, Boned-Juliani B, Lou-Arnal LM. Fasting plasma glucose variability as a risk factor of retinopathy in Type 2 diabetic patients. J Diabetes Complications 2003;17(2):78-81.

BRIEFLY SURGILIGHT EXPANDS USE OF EXCIMER LASER TECHNOLOGY. SurgiLight has granted an exclusive three-year license for the EX-308 Excimer laser technology to RA Medical Systems, Inc., of Carlsbad, Calif., a privately held developer, manufacturer and marketer of equipment for the treatment of various medical conditions. RA Medical anticipates introducing its Pharos EX-308 Excimer laser system this summer, for treatment by dermatologists of psoriasis and vitiligo (pigmentation loss). The FDA has cleared the technology itself for treatment of these two disorders, which by some estimates affect nearly 11 million Americans. GENE INHIBITING MAY REDUCE APOPTOSIS IN GLAUCOMATOUS PATIENTS. Senesco Technologies, Inc., recently announced that inhibiting the expression of its patent-pending gene, apoptosis eucaryotic Initiation Factor 5A ("Factor 5A"), has been shown to reduce apoptosis by up to 70 percent in preclinical studies with human lamina cribrosa cells taken from human optic nerve heads. Apoptosis is a critical factor leading to blindness in glaucoma patients; Senesco is a research and development company focusing on technology that regulates the onset of cell death. A company spokesperson says that the finding indicates that blocking the expression of Factor 5A could potentially be an effective treatment for glaucoma. ACNE DRUG MAY HELP PREVENT BLINDNESS IN STARGARDT’S MD. In a recent edition of the Proceedings of the National Academy of Sciences, investigators at the University of California at Los Angeles reported that the acne drug Accutane (Roche Holding AG) suppresses the accumulation of toxic pigments in mice bred to have a genetic defect simulating Stargardt"s macular degeneration. The inherited progressive disease, for which there is no treatment, causes blindness in approximately 30,000 children and young adults in the United States by disrupting a protein responsible for flushing out all-trans-retinaldehyde, a byproduct of vision, from photoreceptors in the retina. One of Accutane’s possible side effects is night blindness — it interferes with visual pigment recycling. In the Stargardt’s mice injected daily with Accutane over two months, toxins stopped accumulating in the eyes, with no effect on daylight vision. NATIONAL SURVEY: ITCHY, WATERY EYES ARE MOST ANNOYING ALLERGY SYMPTOM. A U.S. survey of 1,000 people conducted last month by Opinion Research Corporation International on behalf of Novartis Ophthalmics shows that itchy, watery eyes are the single most annoying allergy symptom among sufferers of common allergies, topping runny nose, sneezing, and scratchy throat. Yet more than two-thirds of those surveyed believe that their ocular allergy symptoms can be sufficiently treated with oral medications, and 30 percent were unaware that prescription eyedrops are available specifically to treat eye allergies.

	It"s only been up and running a few short weeks. Yet, it"s already clear that the Check Yearly. See Clearly.(SM) marketing campaign is opening consumers" eyes to the benefits of regular eye exams. Call the Vision Council of America at 800-424-8422 today or visit checkyearly.com for your free promotional materials.

Subscriptions: Review of Ophthalmology Online is provided free of charge as a service of Jobson Publishing, LLC. If you enjoy reading Review of Ophthalmology Online, please tell a friend or colleague about it. Forward this newsletter or send this address: [email protected]. To change your subscription, reply to this message and give us your old address and your new address; type "Change of Address" in the subject line. To unsubscribe, reply to this message and type "Unsubscribe Me" in the subject line. Advertising: For information on advertising in this e-mail newsletter or other creative advertising opportunities with Review of Ophthalmology, please contact publisher Rick Bay, or sales managers James Henne, Michele Barrett or Lynn Grode. News: To submit news, send an e-mail, or FAX your news to 610.492.1049