Volume 4, Number 38

Monday, September 20, 2004

In this issue: (click heading to view article)
		Corneal Reconstruction with Tissue-engineered Autologous Oral Mucosal Epithelium
		Method for Comparing Measure of Visual Function and Structural Measure of the Optic Nerve Head
		Endophthalmitis Caused by Streptococcus pneumoniae
		Insulin Resistance and Proliferative Retinopathy in Type II Diabetes Patients
		Briefly

Corneal Reconstruction with Tissue-engineered Autologous Oral Mucosal Epithelium Ocular trauma or disease may lead to severe corneal opacification and, consequently, severe loss of vision as a result of complete loss of corneal epithelial stem cells. Transplantation of autologous corneal stem-cell sources is an alternative to allograft transplantation and does not require immunosuppression, but it is not possible in many cases in which bilateral disease produces total corneal stem-cell deficiency in both eyes. Investigators at Japan"s Osaka University Medical School, Tokyo Women"s Medical University and the University Graduate School of Medicine studied the use of autologous oral mucosal epithelial cells as a source of cells for the reconstruction of the corneal surface. Researchers harvested 3 x 3-mm specimens of oral mucosal tissue from four patients with bilateral total corneal stem-cell deficiencies. Tissue-engineered epithelial-cell sheets were fabricated ex vivo by culturing harvested cells for two weeks on temperature-responsive cell-culture surfaces with 3T3 feeder cells that had been treated with mitomycin C. After conjunctival fibrovascular tissue was surgically removed from the ocular surface, sheets of cultured autologous cells that were harvested with a simple reduced-temperature treatment were transplanted directly to the denuded corneal surfaces (one eye of each patient) without sutures. Complete reepithelialization of the corneal surfaces occurred within one week in all treated eyes. Corneal transparency was restored and postoperative visual acuity improved remarkably in all four cases. During a mean follow-up period of 14 months, all corneal surfaces remained transparent. There were no complications. The authors of the study believe that this method may be used to reconstruct corneal surfaces and can restore vision in other patients with bilateral severe disorders of the ocular surface.

SOURCE: Nishida K, Yamato M, Hayashida Y, et al. Corneal reconstruction with tissue-engineered cell sheets composed of autologous oral mucosal epithelium. New Eng J Med 2004; 351(12):1187-96.

Method for Comparing Measure of Visual Function and Structural Measure of the Optic Nerve Head Researchers at Columbia University (NY) developed a method for comparing multifocal visual-evoked potential (mfVEP) responses and behaviorally determined visual fields with structural measures of the optic nerve head. Humphrey 24-2 visual fields and mfVEPs were obtained from each eye of 20 patients with open-angle glaucoma. Investigators performed monocular and interocular analyses to identify locations with abnormal mfVEP responses. They assessed optic discs with a confocal scanning laser ophthalmoscope (Heidelberg Retina Tomograph II). The image of the optic nerve head was divided into six sectors; the rim and disc area measurements for each sector were compared with those in a normal database using Moorfields regression analysis. The optic nerve head measurements for the six sectors were related to the Humphrey visual field locations and the 60 sectors of the mfVEP display. Of 240 sectors tested (40 eyes times six sectors), 18.8 percent on Humphrey visual field, 22.1 percent on mfVEP and 10.8 percent on confocal scanning laser ophthalmoscopic testing were significantly different from those of control subjects. There were no significant deficits in 165 sectors. Comparisons of the Humphrey visual field and mfVEP results showed agreement for 86.7 percent of the sectors. The confocal scanning laser ophthalmoscopic results were in agreement for 84.6 percent of these sectors. The authors conclude that although the results of the functional and structural measures showed general agreement, the clear examples of disagreements in this study merit further investigation.

SOURCE: Greenstein VC, Thienprasiddhi P, Ritch R, et al. A method for comparing electrophysiological, psychophysical, and structural measures of glaucomatous damage. Arch Ophthalmol 2004;122(9):1276-84.

Endophthalmitis Caused by Streptococcus pneumoniae Despite prompt treatment with appropriate antibiotics, endophthalmitis caused by Streptococcus pneumoniae is associated with a poor visual prognosis, according to a retrospective, observational case series by the Bascom Palmer Eye Institute of Miami. Investigators reviewed the records of all patients with culture-positive endophthalmitis caused by S. pneumoniae who were treated at the Bascom Palmer Eye Institute between January 1, 1989 and December 31, 2003. Main outcome measures were visual acuity and antibiotic sensitivities. Twenty-seven eyes of 27 patients met study inclusion criteria. The median follow-up was seven months (range, three months to 10 years). Clinical settings included acute postoperative (10 eyes), corneal stitch abscess (5), corneal ulcer (3), bleb-associated (4), post-trauma (3) and endogenous (2). Eighteen cases (67 percent) were acute-onset (less than three weeks from event), with a median interval between event and presentation of endophthalmitis of five days (range, one day to 16 days). Nine cases (33 percent) were delayed-onset (median, 27 months; range, three to 121 months). Initial visual acuity was hand motions or better in 11 cases (41 percent). Initial therapeutic procedures included vitreous tap and injection of intravitreal antibiotics in 15 eyes (56 percent), pars plana vitrectomy and injection of intravitreal antibiotics in 10 eyes (37 percent), and evisceration in two eyes (7 percent). Seventeen (68 percent) of 25 eyes received intravitreal dexamethasone. Twelve patients (48 percent) received additional doses of intraocular antibiotics, and 11 patients (44 percent) underwent secondary surgical intervention within one week of diagnosis. The S. pneumoniae isolates showed sensitivity patterns as follows: 27/27 vancomycin, 13/13 clindamycin, 6/6 cefazolin, 11/11 ciprofloxacin, 14/14 moxifloxacin, 24/26 (92 percent) ofloxacin, 12/14 (86 percent) levofloxacin, 13/14 (93 percent) gatifloxacin and 1/13 (8 percent) gentamicin. The organism was sensitive to at least one antibiotic administered initially in all cases. Final visual acuity was 20/400 or better in eight of 27 cases (30 percent), but 10 eyes (37 percent) had a final vision of no light perception.

SOURCE: Miller JJ, Scott IU, Flynn HW Jr., et al. Endophthalmitis caused by Streptococcus pneumoniae. Am J Ophthalmol 2004;138(2):231-6.

Insulin Resistance and Proliferative Retinopathy in Type II Diabetes Patients In a cross-sectional, case-control study, investigators at Italy"s Mario Negri Institute for Pharmacological Research explored the association of proliferative diabetic retinopathy (PDR) with insulin resistance (IR) in Type II diabetics with serum creatinine less than 2.0 mg/dl. For each PDR case, researchers identified one reference case with background diabetic retinopathy (BDR) and two controls without retinopathy. IR was evaluated by hyperinsulinemic euglycemic clamp; retinopathy was evaluated by indirect ophthalmoscopy and photography. Patients were matched by age, gender and body mass index. The 28 PDR patients had higher IR and low-density lipoprotein cholesterol and triglyceride levels than the 29 BDR patients, but comparable levels of glycosylated hemoglobin. Compared with the 58 patients without retinopathy, those with PDR had higher levels of IR, low-density lipoprotein cholesterol and albuminuria; those with BDR had higher glycosylated hemoglobin but comparable IR. At multivariate regression analysis, IR was the only independent marker of PDR among patients with retinopathy. IR also retained its independent predictive value at multiple comparison among all groups (by Kruskal-Wallis test). Authors concluded that in Type II diabetes, IR is an independent specific marker of proliferative retinopathy that may characterize patients at increased risk for blindness who may benefit most from early screening and therapeutic intervention. They believe that longitudinal studies are needed to evaluate the role of IR in the pathogenesis of proliferative retinopathy.

SOURCE: Parvanova A, Iliev I, Filipponi M, et al. Insulin resistance and proliferative retinopathy: a cross-sectional, case-control study in 115 patients with Type 2 diabetes. J Clin Endocrinol Metab 2004;89(9):4371-6.

 

BRIEFLY FDA APPROVES VERISYSE ARTISAN PHAKIC INTRAOCULAR LENS FOR MYOPIA. Advanced Medical Optics, Inc. (AMO) and Ophtec USA, Inc., have announced FDA approval of the Verisyse/Artisan phakic intraocular lens (IOL) for use in patients with myopia. The IOL is the first lens of its kind to receive FDA approval. The patented lens design was introduced by Ophtec in Europe more than 17 years ago and has been safely implanted in more than 150,000 eyes worldwide. Ophtec BV manufactures and distributes the lens under the trade name Artisan in all markets except North America and Japan. In 2002, AMO acquired global distribution rights to the phakic IOL, which it markets under the Verisyse brand. AMO is the exclusive source for the product in North America and Japan. The FDA-approved product labeling will indicate that the Verisyse/Artisan lens is suitable for the reduction or elimination of myopia in adults with myopia ranging from -5.0D to -20.0D and in patients aged 21 and older. The FDA approval followed Ophtec USA’s submission of a Pre-Market Approval (PMA) application, which received expedited review status in August 2003. AMO has begun coordinating surgeon training and certification for the Verisyse lens in the United States; the company expects to begin releasing the product to trained surgeons by October 2004. Information about the Verisyse lens and procedure is available at www.visioninfocus.com. NIDEK LAUNCHES ADVANCED AUTO LENSMETER. NIDEK Co., Ltd., has announced the worldwide launch of its LM-1000/P Auto Lensmeter, which uses advanced and dynamic technologies to provide faster, easier and more accurate measurements of progressive power lenses of all types. The lensmeter also incorporates technologies for UV transmittance measurements, unique marking and inking on lenses with special coatings, and finishes and automatic lens type detection. For more information, call 510-226-5700, ext. 803. OASIS MEDICAL INTRODUCES DISPOSABLE BIMANUALS. Oasis Medical has announced a new line of disposable bimanuals, with separate irrigation and aspiration functions that provide surgeons with more control and flexibility during cortex removal and capsule polishing. The disposable bimanuals include a blue irrigation handpiece, which is curved with a textured tip, closed end and a dual 0.5-mm oval port; and a purple aspiration handpiece, which is curved with a textured tip, closed end and round 0.3-mm port. Both are currently available in 19-g, 20-g and 21-g sizes. Additional tip configurations will be available in the future. For more information, call 800-528-9786 or 909-305-5400.

 

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