Review of Ophthalmology Online

Volume 3, Number 36

Monday, September 8, 2003

In this issue: (click heading to view article)

		Ocular Drug Delivery Via Polylactide Nanoparticles

		Safety and Outcomes of Bilateral Cataract Surgery

		Neutrophil and Eosinophil Participation in AKC and VKC

		Gamma Knife Radiosurgery of Large Choroidal Melanomas

		Briefly

Ocular Drug Delivery Via Polylactide Nanoparticles

Specific targeting of intraocular tissues with encapsulated material in polylactide (PLA) nanoparticles (NPs) is a feasible vehicle for ocular drug delivery, according to findings by the National Institute of Health and Medical Research (Paris).

In the study, animal eyes received a single intravitreous injection (5 micro L) of an NP suspension (2.2 mg/mL) encapsulating either Rh-6G (Rh) or Nile red (Nr). Researchers studied NP localization within the intraocular tissues after sacrifice using environmental scanning electron microscopy (ESEM), confocal microscopy, light microscopy histology, fluorescence microscopy and immunohistochemistry. Eyes injected with blank NPs, free Rh, or PBS solution provided the control.

ESEM showed the flow of the NPs from the site of injection into the vitreous cavity and their rapid settling on the internal limiting membrane. Histology demonstrated the anatomic integrity of the injected eyes and showed no toxic effects. Researchers observed a mild inflammatory cell infiltrate in the ciliary body six hours after the injection and in the posterior vitreous and retina at 18 to 24 hours after injection. The intensity of inflammation decreased markedly by 48 hours. Confocal and fluorescence microscopy and immunohistochemistry showed that a transretinal movement of the NPs was gradually occurring, with a later localization in RPE cells. Rh encapsulated within the injected NPs diffused and stained the retina and RPE cells. PLA NPs were still present within the RPE cells four months after a single intravitreous injection, suggesting that a steady and continuous delivery of drugs might be achieved using this method.

SOURCE: Bourges JL, Gautier SE, Delie F, et al. Ocular drug delivery targeting the retina and retinal pigment epithelium using polylactide nanoparticles. Invest Ophthalmol Vis Sci 2003;44(8):3562-9.


		Click here for more information about LUMIGAN^®.

Safety and Outcomes of Bilateral Cataract Surgery

A Toronto retrospective study to evaluate the safety and outcomes of simultaneous bilateral cataract surgery (SBCS) showed that it does not necessarily cause an increased incidence of intraoperative or postoperative complications.

The study reviewed the results of 1,020 consecutive patients (2,040 eyes) who had SBCS by endolenticular phacoemulsification through a clear corneal incision on the corneal steep axis with foldable posterior chamber intraocular lens implantation. The same surgeon performed all surgeries from January 1996 to January 2002 as two consecutive independent procedures under topical and intracameral anesthesia. Outcome measures included intraoperative and postoperative complications, postoperative uncorrected and best spectacle-corrected visual acuities, refractive error and patient satisfaction.

Results showed that in SBCS, complications were few and would not likely have been prevented had the surgery been performed monocularly. Visual acuity results were good and patients were pleased. No complications were observed that could be attributed to the SBCS procedures.

SOURCES: Arshinoff SA, Strube YNJ, Yagev R. Simultaneous bilateral cataract surgery. J Cataract Refract Surg 2003;29(7):1281-91.

Neutrophil and Eosinophil Participation in AKC and VKC

Both neutrophils and eosinophils play an active role in the pathogenesis of atopic keratoconjunctivitis (AKC) and vernal keratoconjunctivitis (VKC), according to a multicenter retrospective study conducted in Texas, Utah, Massachusetts and Rome. This role is evidenced by the extracellular deposition of the specific granule proteins of neutrophils and eosinophils.

At three centers, clinicians obtained conjunctival specimens from patients with AKC, VKC and normal subjects. Researchers used indirect immunofluorescent staining to localize neutrophil elastase (NE) and eosinophil granule major basic protein (MBP) in serial sections of all specimens.

Specimens from AKC and VKC patients revealed extracellular deposition of NE and MBP. Control specimens showed no or minimal extracellular NE and no MBP. Statistical analysis demonstrated significantly greater extracellular MBP deposition in AKC specimens compared to controls, and VKC specimens showed significantly greater staining for both extracellular MBP and NE.

SOURCE: Trocme SD, Leiferman KM, George T, et al. Neutrophil and eosinophil participation in atopic and vernal keratoconjunctivitis. Curr Eye Res 2003;26(6):319-25.

Gamma-knife Radiosurgery of Large Choroidal Melanomas

Eye-preserving surgery in patients with large choroidal melanomas commonly includes local resection or radiosurgery. Brachytherapy can be applied only to small tumors in adequate localization, while radiosurgery (charged particles or gamma-knife) can be applied to all other tumors. In this study, researchers report on their three-year results of 100 patients treated with gamma-knife radiosurgery.

All patients received a single fraction gamma-knife treatment with a retrobulbar block. The radiation dose was 50 Gy; all tumors were within the 50 percent isodosis range. Tumors were inaccessible for Ru106 brachytherapy because they were too large (maximum height greater than 6.0 mm, basis diameter greater than 19 mm), contact to optic disc exceeded 90 degrees, or infiltration into the ciliary body was present.

Of the 100 patients, 73 were followed for one year, 33 for two years and 17 for three years. Local tumor control was 98 percent (two recurrences). Complications following radio-surgery were rubeosis iridis (12 percent of patients after one year, 15 percent after two years, six percent after three years) and secondary glaucoma (14 percent of patients after one year, nine percent after two years, six percent after three years). Total enucleation rate was 6.3 percent per year. The tumors were found at the posterior pole (61 percent), middle periphery (21 percent) or ciliary body (18 percent). Functional results depended on tumor localization in the eye; after a mean of 1.9 years follow-up, visual acuity was stable (+/-3 lines) in 71 percent of patients with a tumor in the middle periphery, while 19 percent of tumors with infiltration into the ciliary body and zero percent of tumors at the posterior pole showed stable visual acuity.

Researchers concluded that gamma-knife radiosurgery offers a well-tolerated, eye-preserving treatment for patients with large choroidal melanoma in the middle periphery. They point out that, compared with other radiosurgery therapies, gamma-knife radiosurgery offers a fast technique that requires only a single visit.

SOURCE: Thiel MJ, Mueller AJ, Schaller U, et al. Three year results of stereotactic radiosurgery of large choroidal melanomas with the gamma-knife. Spektrum der Augenheilkunde 2003;17:3.

2003 RED BOOK OF OPHTHALMOLOGISTS

A Comprehensive Directory of More Than 16,000 Ophthalmologists

Pre-Publication Price: $99.00
To order, click here.

BRIEFLY

HYDROKERATOME SYSTEM INTRODUCED AT ESCRS 2003. VisiJet Inc. will introduce its HydroKeratome Waterjet System at the European Society of Cataract and Refractive Surgeons (ESCRS) annual meeting in Munich, Germany, September 6 to 10. Unlike mechanical microkeratome systems, VisiJet's FDA-approved system uses a proprietary high-pressure micro beam of water to cut corneal tissue. VisiJet plans to provide hands-on "wet labs" at the ESCRS meeting for surgeons who wish to try out the HydroKeratome. For more information, go to www.visijet.com/docs/technology.htm.

LCA-VISION NEWS. LCA-Vision Inc., which provides laser vision correction services under the LASIKPlus brand, says that it aimed to complete the installation of wavefront analyzers to provide the LASIKPlus custom laser vision correction procedure in all of its U.S. markets by August 29. Custom LASIK equipment installations at LASIKPlus facilities include the Alcon, Inc. LADARWave system, approved by the FDA in October 2002, and the VISXWaveScan System, approved by the FDA in May 2003. LCA-Vision has offered the custom LASIK procedure in its Canadian facilities since October 2001 and in five U.S. markets as of June 30, 2003. In other news, LCA-Vision has signed an agreement with the OptiCare Eye Health Network, a North Carolina-based unit of OptiCare Health Systems Inc., that will provide OptiCare's two million covered benefit customers with access to LCA-Vision's National LASIK Network. LCA-Vision owns and operates 33 LASIKPlus facilities in the United States, two centers in Canada and a joint venture in Europe.

CORRECTION. Last week's Review of Ophthalmology Online reported that Ophtec USA, Inc. and Advanced Medical Optics, Inc. (AMO) received FDA pre-market approval (PMA) and expedited review status for the Artisan/Verisyse phakic IOL. In fact, the FDA accepted the PMA application but has not yet granted approval. ROO regrets the error.


		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: . 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. If you do not want to receive Review of Ophthalmology Online, reply to this message and type "Unsubscribe: Review of Ophthalmology Online" 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 , or sales managers , or .

News: To submit news, , or FAX your news to 610.492.1049