Avedro Announces Completion Of 1st US Phase III Corneal Cross-Linking Clinical Trials

Avedro, Inc. today announced the completion of all one-year follow-up visits for patients enrolled in its two multi-center Phase III studies evaluating the safety and efficacy of corneal collagen cross-linking for the treatment of progressive keratoconus and ectasia following refractive surgery.

Keratoconus is a degenerative disease of the eye and is the leading cause of corneal transplants in the US today. Ectasia following refractive surgery is a complication following various types of surgery, including LASIK, a surgical procedure for correcting myopia (short sightedness) and hyperopia (far sightedness). Outside the US, Cross-linking has been deemed safe and effective and is approved for use in treating keratoconus and ectasia post-refractive surgery.

Dr. Peter Hersh, a leading refractive surgeon and Medical Monitor for Avedro’s clinical trial stated, “Avedro’s efforts to make this clinically important treatment available to US patients is applauded by all US ophthalmologists who today lack any approved therapeutic treatment to halt the progression of these sight threatening conditions.”

“I am extremely pleased that we have reached this important stage in the US clinical trials and our team is working diligently to accomplish a timely analysis of data,” said David Muller, CEO of Avedro. “Outside the US, cross-linking has become the standard of care for treating weak and ectactic corneas. It is our hope to bring this technology to the US in the near future.”

Source:

Avedro, Inc.

Animal Model Of Macular Degeneration Paves Way For Development Of Cures

A new study of age-related macular degeneration (AMD), a disease that affects more than nine million Americans, will pave the way for the biopharmaceutical industry to develop better treatments and cures, according to the Foundation Fighting Blindness, which partially funded the research.

“This is the first time that scientists have been able to create an AMD animal model that closely represents the disease in people,” said Stephen Rose, Ph.D., Chief Research Officer, Foundation Fighting Blindness. “Though there are some treatments for the wet form of AMD, we still don’t have a cure for the condition, and millions of people are still at risk of losing their vision to both the dry and wet forms. This new model will greatly enhance the development of better treatments and potentially a cure.”

Researchers at the Cleveland Clinic Lerner College of Medicine used oxidative chemicals to sensitize the immune systems in mice and create AMD . The study is titled “Oxidative damage-induced inflammation initiates age-related macular degeneration,” and was published in the online edition of the scientific journal Nature Medicine on January 27.

Once developed, therapies for the dry form, or early stage of AMD, could be implemented before vision is lost, which would be a dramatic breakthrough in the treatment of the disease, Rose said.

Click here for a copy of the study.

The Foundation Fighting Blindness (www.FightBlindness) is the largest source of non-governmental funding for retinal degenerative disease research in the world. The urgent mission of The Foundation Fighting Blindness is to drive the research that will provide preventions, treatments and cures for people affected by retinitis pigmentosa, macular degeneration, Usher syndrome, and the entire spectrum of retinal degenerative diseases.

Source: David Harrison

Foundation Fighting Blindness

Sirion Therapeutics Highlights Pivotal Trial Results Of Durezol(TM) At The American Society Of Cataract And Refractive Surgery Annual Symposium

Sirion Therapeutics, Inc., a
privately held ophthalmic-focused biopharmaceutical company, announced the presentation of data from two Phase 3 clinical trials of
Durezol(TM) (difluprednate ophthalmic emulsion) 0.05%, a topical steroid in
the treatment of postoperative ocular inflammation. The results were given
in a presentation by Michael Korenfeld, MD during the American Society of
Cataract and Refractive Surgery Annual Symposium in Chicago, Illinois.

The two multi-center studies evaluated the safety and efficacy of
Durezol(TM) 0.05% compared to placebo dosed twice a day (BID) and four
times a day (QID) beginning 24 hours after ocular surgery. The studies
included 438 subjects who presented with an anterior chamber cell grade 2
(greater than or equal to 10 cells) or higher the day after surgery. The
clinically and statistically significant findings demonstrated that
Durezol(TM), at both the BID and QID dosing regimens, was superior to
placebo in achieving the primary endpoint of proportion of subjects with an
anterior chamber cell grade of 0 (less than or equal to 1 cell) on Day 8,
with 30% of subjects in the BID group reaching Grade 0 versus 9% in the
placebo group. Of the subjects in the QID group, 35% reached Grade 0 on Day
8. In addition, Durezol(TM) maintained superiority over placebo through the
treatment period (Day 15), with 56% in the BID group and 63% in the QID
group reaching Grade 0 versus 16% in the placebo group.

Further data from the presentation demonstrated that both the BID and
QID dosing regimens were superior to placebo with regard to change from
baseline in anterior chamber cell count at Day 8. The mean reduction in
cell count for subjects in both the BID and QID groups was 19 cells and the
mean reduction in the placebo group was 6 cells. In addition, the
proportion of subjects who reached “clinical cure” (defined as anterior
chamber cell count less than or equal to 5 and flare score of 0) at Day 15
was 73% in the BID group and 71% in the QID group versus 27% in the placebo
group (p

New Technique May Spot Evidence Of Macular Degeneration Years Earlier

A layer of “dark cells” in the retina that is responsible for maintaining the health of the light-sensing cells in our eyes has been imaged in a living retina for the first time.

The ability to see this nearly invisible layer could help doctors identify the onset of many diseases of the eye long before a patient notices symptoms. The findings are reported in Investigative Ophthalmology and Visual Science.

“Our goal is to figure out why macular degeneration, one of the most prevalent eye diseases, actually happens,” says David Williams, director of the Center for Visual Science and professor in the Institute of Optics at the University of Rochester. “Macular degeneration affects one in 10 people over the age of 65, and as the average age of the U.S. population continues to increase, it is only going to get more and more common. We know these dark retinal cells are compromised by macular degeneration, and now that we can image them in the living eye, we might be able to detect the disease at a much earlier stage.”

In 1997, Williams’ team was the first to image individual photoreceptor cells in the living eye, using a technique called adaptive optics, which was borrowed from astronomers trying to get clearer images of stars. To image the dark cells behind the photoreceptors, however, Williams employed adaptive optics with a new method to make the dark cells glow brightly enough to be detected.

The cells, called retinal pigment epithelial, or RPE cells, are nearly black, and form a layer that recharges the photoreceptor cells of the eye after they are exposed to light, Williams explains. The photoreceptors contain molecules called photopigments. When light strikes these molecules, they absorb the light and change shape, sending a signal to the brain indicating they’ve “seen” light.

Once a photopigment molecule absorbs light, says Williams, it needs to get recharged, so it is shuttled out of the photoreceptor and down to the RPE cells. The RPE cells recharge the photopigment molecules and send them back to the photoreceptors to start the process again. In addition, the RPE layer keeps the photoreceptors healthy by collecting and storing toxic waste products that are produced during the process of regenerating the photopigment. In macular degeneration, for reasons that are not yet completely clear, the RPE cells are unable to provide this support for the photoreceptors and both kinds of cells eventually die.

Given their critical role supporting the photoreceptors, Williams says that scientists will benefit from being able to image RPE cells in patients to see what is malfunctioning in individual cells.

To see these dark cells, Williams and his colleagues Jessica Morgan, postdoctoral fellow at the University of Pennsylvania, Alf Dubra, postdoctoral fellow in Williams’ laboratory, Bob Wolfe, technical associate in Williams’ laboratory, and Bill Merigan, professor of Ophthalmology, Visual Science, and Brain and Cognitive Sciences at the University of Rochester, exploit a trait of the toxic chemicals the RPE were collecting from the photoreceptors.

“These nasty chemicals fluoresce – they glow just a little under the right conditions,” says Williams. “When you shine blue or green light into the eye, the chemicals in the RPE shine back green and yellow. It’s an incredibly dim glow, but when we use adaptive optics, we can take pictures of these chemicals in individual RPE cells.”

Williams says many scientists believed imaging single RPE cells in the living eye would be impossible. He says he wasn’t even convinced it could be done. When he and his team imaged the first photoreceptors in 1997, the RPE cells appeared pitch black.

Williams and his team now hope to learn exactly how RPE cells are related to macular degeneration. At the moment, scientists aren’t sure how the disease starts, but being able to monitor the health of individual RPE cells may help doctors begin to piece together a picture of what mechanisms are malfunctioning in the retina. Williams also says that since the technique may eventually be able to spot illness in the RPE long before the patient experiences symptoms, doctors could start patients on therapies early enough to possibly slow or stop the onset of macular degeneration. Currently, when a patient begins treatment, a great deal of irreparable damage has been done.

This research was funded by the National Institutes of Health.

About the University of Rochester

The University of Rochester (rochester.edu/) is one of the nation’s leading private universities. Located in Rochester, N.Y., the University gives students exceptional opportunities for interdisciplinary study and close collaboration with faculty through its unique cluster-based curriculum. Its College of Arts, Sciences, and Engineering is complemented by the Eastman School of Music, Simon School of Business, Warner School of Education, Laboratory for Laser Energetics, Schools of Medicine and Nursing, and the Memorial Art Gallery.

Source: Jonathan Sherwood

University of Rochester

Wet Age-Related Macular Degeneration, Benefits Of Lucentis, Preliminary Phase III Data From Head-To-Head Study

Genentech, Inc. (NYSE: DNA)
announced today positive one-year results from its second pivotal Phase III
study of the investigational drug Lucentis(TM) (ranibizumab) in patients with
wet age-related macular degeneration (AMD). Data from the ANCHOR study
comparing Lucentis to verteporfin (Visudyne(R)) photodynamic therapy (PDT)
showed a difference in mean change in visual acuity of 18 letters for patients
treated with 0.3 mg of Lucentis and 21 letters for patients treated with 0.5
mg of Lucentis from study entry compared to those treated with PDT at 12
months.

In the first year of this two-year study, patients treated with
Lucentis gained an average of 8.5 letters in the 0.3 mg dose group and 11
letters in the 0.5 mg dose group compared to patients treated with PDT, who
lost an average of 9.5 letters. In November 2005, Genentech announced that the
Phase III ANCHOR study met its primary efficacy endpoint of maintaining vision
(defined as a loss of less than 15 letters in visual acuity) in patients with
wet AMD. One-year data from the ANCHOR study were presented today during
Macula 2006, a medical symposium held in New York and sponsored by the
Manhattan Eye, Ear & Throat Hospital.

“Lucentis is the first investigational therapy that has shown improved
vision, not just a slowing of vision loss, in patients with all types of wet
AMD,” said Peter K. Kaiser, M.D., director, Clinical Research Center, The
Cleveland Clinic Cole Eye Institute, who presented the data today. “As a
result, physicians may be one step closer to being able to set a new
expectation for the future treatment of this condition.”

An analysis of the one-year data showed that adverse events were similar
to those seen in earlier trials of Lucentis. Common ocular adverse side
effects that occurred more frequently in the Lucentis arms than in the control
group were mild to moderate and included conjuctival hemorrhage, increased
intraocular pressure, eye pain and vitreous floaters. Serious ocular adverse
events that occurred more frequently in the Lucentis-treated arms were
uncommon and included endophthalmitis and intraocular inflammation (each
reported in less than 1 percent of patients per group). Among non-ocular
serious adverse events, the frequency of cerebral vascular events was less
than 1 percent of patients per group. The frequency of myocardial infarctions
was slightly higher in patients treated with 0.5 mg of Lucentis (2.1 percent)
than in the other two arms (0.7 percent).

Additional key clinically meaningful study findings include:

— 94 percent of patients (132/140) treated with 0.3 mg of Lucentis and
96 percent (134/139) of those treated with 0.5 mg of Lucentis lost
fewer than 15 letters compared to baseline, the primary efficacy
endpoint of the study, compared with 64 percent (92/143) of those
treated with PDT [p

— Nearly 36 percent of patients (50/140) treated with 0.3 mg of Lucentis
and 40 percent of patients (56/139) treated with 0.5 mg of Lucentis
improved vision by a gain of 15 letters or more compared with
approximately 6 percent of patients (8/143) treated with PDT.

— 31 percent of patients (44/140) treated with 0.3 mg of Lucentis and
nearly 39 percent of patients (54/140) treated with 0.5 mg of Lucentis
achieved visual acuity of 20/40 or better at 12 months compared with
approximately 3 percent (4/143) of those treated with PDT.

“Through the extensive clinical study program for Lucentis we have now
shown a significant improvement in vision compared to Visudyne and in patients
with all types of wet AMD,” said Hal Barron, Genentech senior vice president,
Development and chief medical officer. “We look forward to working with the
FDA on our BLA submission and Priority Review request. Given the existing
unmet medical need for patients with wet AMD, we are providing access to
Lucentis for eligible patients through SAILOR, a Phase IIIb safety study.”
In December 2005, Genentech announced that it had submitted a Biologics
License Application (BLA) to the U.S. Food and Drug Administration (FDA) for
the use of Lucentis in the treatment of neovascular wet AMD. The BLA
submission, which included a request for Priority (six-month) Review, is based
on one-year clinical data on the efficacy and safety of Lucentis from two
pivotal Phase III trials, ANCHOR and MARINA, as well as one-year clinical data
from the Phase I/II FOCUS trial.

About the Study

ANCHOR (ANti-VEGF Antibody for the Treatment of Predominantly Classic
CHORoidal Neovascularization in AMD) is a Phase III randomized, two-year,
multi-center, double-masked, active-treatment controlled study comparing two
different doses of Lucentis to PDT in 423 patients with predominantly classic
wet AMD. Patients were randomized 2:1 to receive intravitreal Lucentis
injections (0.3 mg or 0.5 mg dose) once a month or PDT every three months for
two years. Exclusion criteria included prior subfoveal laser treatment, PDT or
experimental treatments for wet AMD. Visual acuity was measured using the
Early Treatment Diabetic Retinopathy Study (ETDRS) chart, the standard method
of quantifying visual acuity. The study is ongoing in the United States,
Europe and Australia. Based on the one-year results, patients in the PDT alone
arm of the study will have access to Lucentis for the remainder of the study.

Additional Phase III Studies

SAILOR

In November 2005, Genentech began enrollment in a Phase IIIb study,
SAILOR, to make Lucentis available to eligible patients. SAILOR (Safety
Assessment of Intravitreal Lucentis fOR AMD) is a Phase IIIb clinical study of
Lucentis for patients with all subtypes of new or recurrent active subfoveal
wet AMD. It is a one-year study designed to evaluate the safety of two
different doses (0.3 mg and 0.5 mg) of Lucentis administered once a month for
three months and thereafter as needed based on re-treatment criteria. The
study will be conducted at more than 100 sites in the United States and will
enroll up to 5,000 patients. Those interested in additional information about
the study can call toll-free 1-888-662-6728.

MARINA

In July 2005, Genentech announced positive preliminary one-year results
from the pivotal Phase III MARINA study (Minimally classic/occult trial of the
Anti-VEGF antibody Ranibizumab In the treatment of Neovascular AMD), a
randomized, two-year, multi-center, double-masked, sham-injection controlled
study evaluating the safety and efficacy of two different doses of Lucentis in
716 patients with minimally classic or occult wet AMD. Nearly 95 percent of
patients treated with Lucentis maintained or improved vision at 12 months.
Additional one-year results include:

— Twenty-five percent (59/238) of patients treated with 0.3 mg of
Lucentis and 34 percent (81/240) treated with 0.5 mg of Lucentis
improved vision by a gain of 15 letters or more compared to
approximately 5 percent (11/238) of patients in the control group as
measured by the ETDRS eye chart.

— Nearly 40 percent (188/478) of Lucentis-treated patients achieved a
visual acuity score of 20/40 or better compared to 11 percent (26/238)
in the control group.

— Patients treated with Lucentis gained an average of seven letters in
visual acuity compared to study entry, while those in the control
group lost an average of 10.5 letters.

— The majority of patients treated with Lucentis (74.8 percent in the
0.3 mg group and 71.3 percent in the 0.5 mg group) experienced a
letter improvement of zero or more compared to 28.6 percent in the
sham group.

In October 2005, Genentech announced that patients in the sham arm of the
MARINA study would be crossed over to active treatment with Lucentis.
Additional one-year data from the MARINA study will be presented at the Macula
Society Meeting in February.

PIER

Genentech is also conducting PIER (A Phase IIIb, Multi-center, Randomized,
Double-Masked, Sham Injection-Controlled Study of the Efficacy and Safety of
Ranibizumab in Subjects with Subfoveal Choroidal Neovascularization with or
without Classic CNV Secondary to Age-Related Macular Degeneration) with 184
patients in the United States. In this trial, Lucentis is administered once
per month for the first three months followed thereafter by doses once every
three months for a total of 24 months. Enrollment in this study is complete,
and preliminary results are expected in the second quarter of 2006.

Lucentis Safety Profile

In clinical trials to date, the most common side effects that occurred
more frequently in the Lucentis arms (0.3 mg and 0.5 mg) than in the control
arms were mild to moderate and included: conjunctival hemorrhage, eye pain,
increased intraocular pressure and vitreous floaters.

Serious ocular adverse events that occurred more frequently in the
Lucentis-treated arms were uncommon and included endophthalmitis and
intraocular inflammation (less than 1 percent for each). Among non-ocular
serious adverse events, cerebral vascular events and myocardial infarctions
were observed in all three arms of both the Phase III MARINA and ANCHOR
studies. The combined rate of these events in these two studies with monthly
dosing was similar in the control and the 0.3 mg Lucentis arms (1.3 percent
and 1.6 percent respectively) and slightly higher in the 0.5 mg Lucentis arm
(2.9 percent).

About AMD

AMD is a major cause of painless central visual loss and is the leading
cause of blindness for people over the age of 60. The National Eye Institute
estimates that there are 1.6 million people with AMD in the United States
alone and that this prevalence will grow to 2.95 million by 2020. AMD occurs
in two forms: dry and wet.

The dry form is associated with atrophic cell death of the central retina
or macula, which is required for fine vision used for activities such as
reading, driving or recognizing faces. The wet form is caused by growth of
abnormal blood vessels, also known as choroidal neovascularization (CNV) or
ocular angiogenesis, under the macula. These vessels leak fluid and blood and
cause scar tissue that destroys the central retina. This results in a
deterioration of sight over a period of months to years.

About Lucentis

Lucentis(TM) (ranibizumab) is a humanized therapeutic antibody fragment
developed at Genentech and designed to bind and inhibit VEGF-A, a protein that
is believed to play a critical role in angiogenesis (the formation of new
blood vessels). Lucentis is designed to block new blood vessel growth and
leakiness, which lead to wet AMD disease progression and vision loss. Lucentis
is being developed by Genentech and the Novartis Ophthalmics Business Unit for
diseases or disorders of the eye. Genentech retains commercial rights in the
United States and Canada, and Novartis has exclusive commercial rights for the
rest of the world.

About Angiogenesis

Genentech is a leader in research and product development in the area of
angiogenesis, the process by which new blood vessels are formed. In 1989
Napoleone Ferrara, M.D., and a team of scientists at Genentech conducted
seminal work in the field, which resulted in the identification and cloning of
a gene termed Vascular Endothelial Growth Factor (VEGF), now known as VEGF-A.

The VEGF-A protein is believed to play a critical role in angiogenesis and
serves as one of the key contributors to physiological or pathological
conditions that can stimulate the formation of new blood vessels. The process
of angiogenesis is normally regulated throughout development and adult life,
and the uncontrolled growth of new blood vessels is an important contributor
to a number of pathologic conditions, including wet AMD.

About Genentech

Genentech is a leading biotechnology company that discovers, develops,
manufactures and commercializes biotherapeutics for significant unmet medical
needs. A considerable number of the currently approved biotechnology products
originated from or are based on Genentech science. Genentech manufactures and
commercializes multiple biotechnology products and licenses several additional
products to other companies. The company has headquarters in South San
Francisco, California and is listed on the New York Stock Exchange under the
symbol DNA. For additional information about the company, please visit
gene.

This press release contains forward-looking statements regarding Lucentis
as a potential therapy and the expected time frame for the PIER trial results.
Such statements are just predictions and involve risks and uncertainties such
that actual results may differ materially. Among other things, the time frame
for the PIER results could be affected by unexpected safety or efficacy
issues, additional time requirements to achieve study endpoints or for data
analysis, or discussions with the FDA or FDA actions; and Lucentis as a
potential therapy could be affected by all of the forgoing and the failure to
receive FDA approval, competition, pricing and the ability to supply product
or a product withdrawal. Please also refer to Genentech’s periodic reports
filed with the Securities and Exchange Commission. Genentech disclaims, and
does not undertake, any obligation to update or revise the forward-looking
statements in this press release.

Genentech, Inc.
gene

View drug information on Lucentis; Photodynamic Therapy; Visudyne.

Refractive Errors Significantly Affect Adults In United States

Approximately half of all adults in the United States aged 20 and older
have refraction errors in their eyes that result in less than 20/20
vision, according to an article released on August 11, 2008 in the Archives
of Ophthalmology, one of the JAMA/Archives journals.

When the eye does not properly focus light on the retina, it results in
nearsightedness, farsightedness, or astigmatism. These refractive
errors account for nearly 80% of vision impairment in residents older
than 12 in the United States. Providing eye care to this population,
including glasses and contact lenses, costs and estimated $3.8 to $7.2
billion US dollars per year.

To investigate the prevalence of refractive error in the U.S. public,
Susan Vitale, Ph.D., M.H.S., and colleagues at the National Eye
Institute, part of the National Institutes of Health in Bethesda,
analyzed data taken as part of the National Health and Nutrition
Examination Survey (NHANES) conducted by the Centers for Disease
Control and Prevention (CDC). In this survey, a nationally
representative sample was selected and noted for demographic
characteristics, and a vision test was administered.

A total 12,010 participants over age 20 performed the survey between
1999 and 2004 with complete data. Approximately half of these adults
had one type of refractive error, including 3.6% who were farsighted,
33.1% who were nearsighted, and 36.2% who had astigmatism. Refractive
error of any kind increased with age, from the youngest age group from
20-39 years (46.3%) to those 40 through 59 (50.6%) to the oldest group
aged 60 or older (62.7%).

Comparing age and sex yielded additional results. Nearsightedness was
less common in those older than 60, but this age group was more likely
to have farsightedness and astigmatism than others. Additionally, in
this older age group, men were more likely to have refractive error
than women (66.8% versus 59.2%). Among 20 to 39 year olds, women were
more likely to be nearsighted than men (39.9% versus 32.6%).

When analyzing ethnicity, Mexican-Americans were less likely to have
refractive errors than non-Hispanic whites or non-Hispanic blacks.

The authors conclude that refractive error is a highly prevalent
condition among the American public. “Refractive error is, therefore,
the most common condition affecting the ocular health of the U.S.
population, involving young adults, middle-aged persons and older
adults of all ethnicities,” they say. “Accurate, current estimates of
the prevalence of refractive error are essential for projecting vision
care needs and planning for provision of vision care services to the
many people affected.”

Prevalence of Refractive Error in the United States, 1999-2004
Susan Vitale, PhD, MHS; Leon Ellwein, PhD; Mary Frances Cotch, PhD;
Frederick L. Ferris III, MD; Robert Sperduto, MD
Arch Ophthalmol. 2008;126(8):1111-1119.
Click
Here For Abstract

Anna Sophia McKenney

Lizard “third Eye” Sheds Light On Evolution Of Color Vision

Johns Hopkins Medicine Media Relations and Public Affairs Media Contact: Audrey Huang 410-614-5105; audreyjhmi.edu Published in the March issue of Science, their lizard study describes how the “side-blotched” lizard’s so-called third, or parietal, eye, distinguishes two different colors, blue and green, possibly to tell the time of day. Specialized nerve cells in that eye, which looks more like a spot on the lizard’s forehead, use two types of molecular signals to sense light: those found only in simpler animals, like scallops, and those found only in more complex animals like humans.

Although the blue-green color comparison method used by the parietal eye is not one shared by humans, it does reveal one potential step in the evolution of color vision, the Hopkins researchers say.

Human light-reception cells responsible for color vision are called cone cells or photoreceptors, and they contain only one kind of pigment per cell – red, green, or blue. A color image results when light-triggered signals in the three different types of cone cells are compared by other nerve cells in the retina as well as the brain.

The lizard’s parietal eye photoreceptors contain two pigments per cell, blue and green. Having two different pigments allows the cell to respond to two different colors of light and process that information within the same cell.

According to the researchers, when the lizard’s third eye sees blue light, the blue pigment triggers a molecule called gustducin, which is very similar to a molecule found in human photoreceptors as well as the lateral eyes of the lizard – those on the sides of its head. But when the lizard’s third eye sees green light, the green pigment triggers a different molecule called Go, known as “G-other,” which also signals light responses in the light-sensing cells of the scallop and other creatures without a backbone. That Go is found in spineless creatures suggests it is the evolutionarily more ancient light-triggering signal.

Although gustducin and Go are different molecules, they are similar and considered “related” proteins. However, gustducin and Go each activate different molecular pathways that work against each other physiologically. Blue light and gustducin generate an “off” response in the nerve cell while green light and Go generate an “on” response.

“It may seem strange to have two opposing signals in the same cell,” says the study’s senior author, King-Wai Yau, Ph.D, a professor in the Solomon H. Snyder Department of Neuroscience at Hopkins, “but the unique mechanism renders these parietal photoreceptors most active at dawn and dusk.”

“So incorporating two different pigments and two separate signaling molecules in one cell may have been an economical way, in a primitive eye with relatively few cell types, to tell the transitions of the day based on changes in the spectrum of sunlight,” says Chih-Ying Su, Ph.D., the first author of the study and a former neuroscience graduate student at Hopkins.

“It’s just like in a small company,” says Yau. “You have to delegate each person to do more things.”

By sharing features found in human photoreceptors as well as those found in simpler organisms like the scallop, the researchers propose that the lizard’s parietal eye photoreceptor cells represent a “missing link” between the light-sensing apparatus in lower animals and ours.

It turns out that some frogs and fish also have a spot on their foreheads that might play the role of a light-sensing third eye. Yau hopes to pursue these structures to obtain more clues about how our photoreceptor cells, the rods and cones, came about. As he says, he’s most curious about how the same function can be achieved in different ways in different animals.

The researchers were funded by the National Eye Institute and the Allene Reuss Memorial Trust.

Authors on the paper are Su, Dong-Gen Luo, His-Wen Liao and Yau of Hopkins, Akihisa Terakita and Yoshinori Shichida of Kyoto University, and Manija Kazmi and Thomas Sakmar of Rockefeller University.

On the Web:
sciencemag/
neuroscience.jhu.edu/

Contact: Audrey Huang
audreyjhmi.edu
Johns Hopkins Medical Institutions

Yearly Mass Antibiotic Treatment Could Eliminate Leading Cause of Blindness

Giving communities with high levels of Chlamydia trachomatis yearly mass antibiotic treatment over a few years could be sufficient to eliminate eye infection caused by the bacterium, suggests an article in this week’s issue of The Lancet.

Chlamydia trachomatiscauses trachoma, an infection of the eyes that may result in blindness after repeated re-infection. Trachoma is the world’s leading cause of blindness. Previous studies have suggested that eye infection with C. trachomatiscould be eliminated after one mass treatment with antibiotics.

However, Sheila West (The Johns Hopkins School University, Baltimore, MD, USA) and colleagues found that in an area of Tanzania with high levels of the bacterium, mass treatment significantly reduced the prevalence of infection in the community but infection re-emerged after 1-year.

Professor West states: “The findings of our community based study show that antibiotic coverage as high as 86% decreases, but does not eliminate, ocular infection with C.trachomatisover 18 months. Trachoma and infectious load began to rise 12 months after treatment, suggesting that yearly mass treatment for this community would be effective.”

Lancet
42 Bedford Sq.
London WC1B 3SL
United Kingdom
thelancet

AMA And RANZCO Oppose Chloramphenicol Rescheduling, Australia

The Australian Medical Association (AMA) and the Royal Australian and New Zealand College of Ophthalmologists (RANZCO) strongly disagree with the decision to reschedule Chloramphenicol eye drops from the Schedule 4 listing to a Schedule 3 medication.

Schedule 4 medications are prescribed by registered medical practitioners or endorsed optometrists. Schedule 3 medications are available to the public from a pharmacist without a prescription.

RANZCO President, Dr Richard Stawell, said today that Chloramphenicol is one of the most frequently used antibiotics prescribed by ophthalmologists.

“Its use should be reserved for bacterial eye infections or to prevent serious infection, postoperatively, and it is very important that it is not used indiscriminately,” Dr Stawell said.

“The AMA and RANZCO have major concerns that pharmacists will be guiding patients in the use of Chloramphenicol. Pharmacists have not been trained to be competent in diagnosing eye disease and do not have the appriopriate equipment to properly examine an eye.

“There is great variety of different causes of a red discharging eye. It is very easy for an incorrect diagnosis to be made, and the wrong drug prescribed. Some eye diseases can cause irreversible loss of sight,” Dr Stawell said.

AMA President, Dr Andrew Pesce, said that first-line eye care is the domain of general practitioners and optometrists, who are readily accessible to patients.

“General practitioners have been specifically trained in clinical diagnosis and appropriate drug use,” Dr Pesce said.

“It takes many years to train a medical practitioner to assess, diagnose and treat eye conditions properly. Pharmacists have not been similarly trained.

“Both the AMA and RANZCO strongly advised against the rescheduling of Chloramphenicol, and we strongly disagree with this decision, which is not in the best interests of people in need of specialised care for their eye conditions,” Dr Pesce said.

Source
Australian Medical Association