APAO’s ‘Vision for the future’ meeting sees continued growth

The Asia-Pacific Academy of Ophthalmology meeting held in conjunction with the AAO and APACRS was large in attendance and program scope.

SINGAPORE — The cultural and economic diversity of the Asia-Pacific region contributed to a diverse program here at the Asia-Pacific Academy of Ophthalmology meeting.

Explosive economic growth in many countries in the region helped account for a large meeting, which hosted more than 4,000 attendees with more than 80 exhibitors.

These exhibitors created “an ophthalmic trade exhibition that is one of the largest ever staged in Asia,” APAO vice president and secretary-general Adrian Koh, MD, said.

To provide information for those attending, the meeting featured 250 faculty speakers, seven named lectures, 12 plenary sessions, 26 symposia, and 64 courses and workshops.

According to APAO president Yasuo Tano, MD, “Members of the APAO are spread over a wide spectrum of social, economic, cultural and religious backgrounds and are delivering eye care to people comprising more than half of the world’s entire population. This may represent the greatest diversity of a single medical society on Earth.”

Highlights from the APAO are presented in this article. Many of these items appeared first on OSNSuperSite.com as daily reports from the meeting. Look to the pages of Ocular Surgery News for expanded coverage of selected items in the future.

Retina/Vitreous

Diabetic retinopathy crisis will change researchers’ role

Arthur S.M. Lim

Diabetic retinopathy is one of the challenges facing Asian ophthalmologists today, said Arthur S.M. Lim, MD, FRCS, referring to reports from the World Health Organization.

“It is quite clear that diabetes mellitus, in particular type 2 diabetes, will explode into a crisis,” he said. “[Diabetes and diabetic retinopathy] will become the major concern of the next 10 years.”

Because of this concern, he said, the research physician will play a more important role in ophthalmology.

Prof. Lim’s remarks about the state of Asian ophthalmology came during the Asia-Pacific Association of Cataract and Refractive Surgeons’ (APACRS) annual meeting held in conjunction with the APAO meeting. He described the “awakening” of Asian ophthalmology in 1990, when the Singapore National Eye Center opened. This awakening, coupled with the establishment of the Singapore Eye Research Institute in 1996, is helping to bring Asian research centers up to the standards of their European and U.S. counterparts, he said.

“This has become one of the most important centers in the world,” he said.

Doctors should always be mindful of the current state of ophthalmology, the goals of organizations such as APAO and APACRS and, in particular, the role of the eye surgeon, Prof. Lim said.

“Today’s doctor must be abreast of the latest research so as to be able to choose the best for his patients,” he said.

Prof. Lim said research centers, such as the one in Singapore, will help surgeons in that region of the world gain access to the best innovations in the most timely manner.

“Doctors need to re-examine the principles that have elevated the medical profession to one of honor,” Prof. Lim said. “What is the role of our surgical skills if not to benefit our fellow man?”

ERG eases hereditary retinal disease diagnosis

Hereditary retinal diseases can be more easily defined because of advances in technology, specifically the electroretinogram, said Yozo Miyake, MD. He delivered the De Ocampo Lecture at the APAO.

Congenital stationary night blindness (CSNB) with normal fundi has been termed “Schubert-Bornschein type” when it shows negative electroretinogram (ERG) configuration, Dr. Miyake said. However, in an analysis of 92 patients at the National Institute of Sensory Organs in Tokyo, Dr. Miyake found that this single term takes in two different disease entities; he dubbed them incomplete and complete CSNB.

“The complete form has no rod function, and the incomplete form has moderate rod function,” he said. “Complete and incomplete types are definitely different entities.”

Fundus albipunctatus (FA) has been categorized as one type of CSNB with unique fundus appearance, he said. The typical clinical characteristic of FA is “enormous delay of rod adaptation.”

An analysis of 29 patients with FA who underwent ERG showed that about 33% were associated with cone dystrophy, “sometimes showing bull’s eye maculopathy,” he said. Cone ERGs were virtually nonexistent in the group, Dr. Miyake said. The patients also showed a specific gene mutation, RDH5.

“We cannot classify FA as a stationary disease because the cone dystrophy is progressive,” Dr. Miyake said.

Dr. Miyake added that occult macular dystrophy is a newly identified macular dystrophy in which the fundi and fluorescein angiography are normal. He said the key for diagnosis “is the abnormal focal macular ERG in spite of normal full-field ERG.”

An analysis of 46 patients indicated clinical findings of progressive decrease of bilateral visual acuity, color vision deficiency and autosomal dominant heredity. He warned that most of these patients are misdiagnosed with psychological problems, optic nerve disease or central nervous system problems.

Retinal surgeons should reconsider viscodissection

Using viscodissection to delineate the plane between a thick vascularized membrane and the retina should be reconsidered by retinal specialists, said Pearl Tamesis-Villalon, MD.

Newer viscoelastics with higher molecular weights have changed the technique, making it viable once again as an option for retinal surgeons, she said.

Advantages of the technique include minimal trauma, exertion of force over a broad area rather than at one single point, and the control of bleeding through the viscous effect of the viscoelastic, she said.

“Although [viscodissection] is not the main surgical technique, it is of great use occasionally, as it can adequately define a space between two surfaces,” Dr. Tamesis-Villalon said.

She said this technique is not meant to replace conventional surgeries but to work as an adjunct to them.

Modified PDT may enhance outcomes in chronic chorioretinopathy

A modified version of photodynamic therapy enhances the treatment’s safety and efficacy for patients with acute or chronic chorioretinopathy, said Wai-Man Chan, MD, who delivered the Nakajima Lecture at APAO and was this year’s recipient of the Nakajima Award. He said conventional forms of PDT have been shown to cause visual disturbances in up to 18% of patients treated and severe vision loss in 1% to 4% of patients. Photoreceptor function is also depressed shortly after PDT applications, he said.

“There is more risk than benefit with the conventional treatment,” he told attendees. Altering the dosage amount and time may help improve the safety profile, he said.

In one study in 55 eyes, Dr. Chan and colleagues used a modified version of verteporfin PDT, and the eyes showed a mean gain of 1.67 lines and a 76% absorption rate. Severe decreases in vision were also eliminated, Dr. Chan said.

Another similar study included patients with acute chorioretinopathy. Of the 39 patients in that study, 18 were treated with PDT with verteporfin and 21 received placebo treatment.

The results in this study were similar to those in the chronic group, Dr. Chan said.

Refractive Surgery

Pupil size important to presby-LASIK outcomes

A patient’s pupil size cannot be overlooked when preparing to perform presby- LASIK, one surgeon stressed.

Jerry Tan, MD, told attendees to remember that small or large pupils can negate the effect of topographically successful treatments.

“When you focus near, the pupil shrinks, so anything done on the outer surface of the cornea has no effect on vision,” Dr. Tan said.

He said presby-LASIK is currently used to treat hyperprolate corneas, steep central island ablations, decentered steep islands and a centered steep annulus. He explained that hyperprolate cornea is the only one of these indications that can be corrected with spectacles if the visual outcome is not satisfactory.

“Presby-LASIK is a hot topic, but I am still up in the air about it,” he said. “There is still a lot to learn and discover with this procedure.”

Femtosecond lasers complement microkeratomes

Surgeons should view femtosecond lasers as a complement to microkeratomes rather than as an alternative, said Chan Wing Kwong, MD.

Femtosecond lasers and microkeratomes are similar in terms of reliability, cost, safety and flap thickness predictability, he said.

“Femtosecond lasers will have applications in abnormal corneas,” he said. Femtosecond lasers can create a different set of flap complications than surgeons are used to seeing with conventional microkeratomes, he added. He said complications can include diffuse lamellar keratitis.

Dr. Kwong said femtosecond lasers can create an infinite variety of cuts and “need to have expanded treatment options to justify their cost.”

He called for non-sponsored, randomized, controlled trials to determine if differences exist in visual acuity between eyes treated with femtosecond lasers and those treated with microkeratomes.

“LASIK is a two-stage procedure. There is no point in making the best flap if you can’t get the best ablation,” he said. “There is too much market-driven emphasis on flaps. Pay attention to laser ablation algorithms and patterns.”

Neural adaptive program expands treatment

Contrast sensitivity and uncorrected visual acuity in low myopes, emmetropic presbyopes and post-refractive-surgery patients may be improved through a neural adaptation program, preliminary study results show.

Donald Tan, MD, described a computerized visual training program that uses Gabor patches to facilitate neural connections in order to enhance “perceptual learning.” The treatment was performed on 113 patients with low myopia, 41 patients with presbyopia and 14 post-refractive surgery patients.

Prof. Tan said the group with low myopia gained 2.8 lines of uncorrected visual acuity and improved contrast sensitivity to within the normal range. Fifty-five patients at 6 months follow-up maintained 85% of the visual improvement, although 16 patients who had been followed to 12 months maintained only 5% of the improvement.

The presbyopic group gained 1.6 lines of uncorrected vision and showed significant improvements in contrast sensitivity, Prof. Tan said. The post-refractive surgery group gained 2.05 lines in uncorrected visual acuity.

“Results to date suggest the treatment improves unaided visual acuity and contrast sensitivity in low myopes, emmetropic presbyopes and post-refractive surgery patients,” Prof. Tan said.

A randomized trial in low to moderate myopia is under way, he said.

Cornea/External Disease

PK with femtosecond laser is promising

Using a femtosecond laser for penetrating keratoplasty produces favorable outcomes, Gerd Auffarth, MD, said.

Gerd Auffarth

He presented results from his first five cases of PK using a femtosecond laser during the APACRS annual meeting, held in conjunction with the APAO meeting.

Patient ages ranged from 50 to 84 years. Indications for PK included granular corneal dystrophy, Fuchs’ endothelial dystrophy, familiar endothelial dystrophy, keratoconus and corneal scars after herpetic keratitis.

Dr. Auffarth said all procedures and postoperative recovery were uneventful.

The surgical technique involved a circular cut starting at 1,000 µm depth in the cornea and moving anteriorly toward the epithelium through the endothelium and stroma, he said. The cutting diameter was 7.8 mm for the recipient and 8 mm for the donor tissue. A double running Hoffman suture was applied to secure the corneal implant, Dr. Auffarth said.

All corneal donors and recipients were treated with the Femtec laser (20/10 PerfectVision).

Dental keratoprosthesis can restore sight in end-stage corneal disease

An osteo-odonto keratoprosthesis (OOKP) procedure developed decades ago is offering hope to patients with end-stage corneal disease, such as Stevens-Johnson syndrome or severe chemical burns, a surgeon here said.

In an interview with Ocular Surgery News, Prof. Tan, deputy director of the Singapore National Eye Center, said the procedure “is for those cases in which nothing else would work. It is probably the most complex series of operations we have, because the procedure replaces the whole front part of the eye. I cannot think of any other ophthalmic procedure that [takes such a long time to perform] and is so complex.”

Prof. Tan, who presented his results with the OOKP procedure at the meeting, said candidates for the surgery must have bilateral blindness but still have a functioning retina and optic nerve.

Since February 2004, the procedure has been performed on 15 patients at the Singapore National Eye Centre in collaboration with the Singapore National Dental Centre. In 13 patients with the longest follow up of 24 months, Prof. Tan reported seven of 13 patients achieved 6/6 vision; nine of 13 are 6/12 or better; and the others have stable vision between 6/30 and 6/120. He attributed the poorer visual acuity in some eyes to pre-existing glaucoma or retinal detachment.

In the first stage of the procedure, a canine tooth of the patient is removed and shaved down to receive an optical PMMA cylinder. This is then implanted under the cheek muscle of the patient.

“We no longer use the ocular surface for this procedure anymore,” Prof. Tan said. “We provide a new surface from the mouth. We use a canine tooth because it’s the largest tooth with a single root. So this tooth-cylinder [implant] is then implanted into the cheek under the muscle, and the tooth is still living, so it’s a combined living, biological implant. Over the next 3 months it will grow a fibrous capsule. There’s a blood supply, and the tooth will recover within this living tissue in the cheek.”

As the last step of this first procedure, a large piece of buccal mucosal tissue is removed from the cheek, the surface of the eye is denuded, and the buccal mucosal tissue is used to create a new front part of the eye.

“We let the buccal mucosa recover, and we let the tooth recover, and about 2 to 3 months later we perform the second stage of the operation,” he said. “We exchange one buccal mucosa for another.”

During the second part of the surgery, the tooth is removed from the cheek, with the surgeon checking for viability and good blood flow, Prof. Tan said.

“We flap the buccal mucosa to expose the cornea, which is still there. We drill a hole in the cornea, and we remove the iris, the lens and the vitreous,” Prof. Tan said. “We just core out the whole front part of the eye to make space for the tooth, and then we put the tooth implant into the cornea.” Concurrent glaucoma and vitreoretinal procedures are also performed as necessary, he said.

The tooth-cylinder complex is then sutured in place and the buccal mucosal flap is stitched back in place. Then a hole is cut in the mucosa, through which the PMMA optic can protrude.

“So now you have a cornea that is replaced by a tooth, which is very strong,” Prof. Tan said. “The tooth in fact is not only the tooth, it’s also part of the maxillary bone. So you have bone and tooth and covering that will be buccal mucosa, and the optic protrudes right through.”

Prof. Tan said the procedure “should only be used in end-stage cases,” and that if an opportunity for a transplant or a stem-cell transplant occurs, surgeons should consider those first.

The OOKP procedure is “for cases considered hopeless,” he said. “These are patients where the whole front of the eye has been destroyed.”

Each stage of the procedure currently takes about 3.5 hours, Prof. Tan said, a decrease from about 7 or 8 hours when he first began performing the procedure.

Physicians: Polymer combination at root of Fusarium outbreaks

A combination of polymers that were added to a common contact lens solution to improve comfort may have played a key role in the Fusarium keratitis outbreaks that occurred last year and earlier this year, Prof. Tan said.

He said the polymer film buildup in Bausch & Lomb’s ReNu contact lens solution “trapped” the Fusarium molecule, leading to clusters of infections in certain regions.

Prof. Tan and colleagues at the Singapore National Eye Center were the first to report the outbreak of Fusarium infections and link them with a contact lens solution.

“The disinfectant in [ReNu with] MoistureLoc is actually very effective,” Prof. Tan said. “The problem is when you add other things in, like the polymers to improve comfort. The polymers are actually trapping the fungus so that the disinfectant, which is very strong, cannot get at the fungus. So it is a formulation problem.”

In an interview with Ocular Surgery News, Prof. Tan said, “What Bausch & Lomb has done is clearly show a plausible sequence of events in which MoistureLoc would be more likely to cause this outbreak than other solutions and that was the three different polymers which trap the fungus in.”

The sequence of events that Bausch & Lomb proposed must take place for infections to occur includes poor compliance by the contact lens wearer as well as susceptibility to infection on the part of the patient. Prof. Tan said B&L has found that the fungus can grow on the tip of an open bottle or on the cap because it is “trapped” there by the polymers.

He added that B&L found the practice of “topping off” that is common among contact lens wearers is another factor that led to the rare cases of Fusarium infection. When a contact lens wearer does not rinse the used solution from the lens case before refilling it with fresh solution, the practice is called topping off, Prof. Tan explained.

Prof. Tan presented data on behalf of B&L during an APAO-sponsored symposium indicating that the combination of polymers in the ReNu with MoistureLoc solution builds up when the water in the solution evaporates. Fusarium can survive in the leftover buildup and attach to the contact lens when it is washed out in the solution, Prof. Tan said. If the wearer topped off the solution instead of cleaning out the contact lens holder, the disinfectant in MoistureLoc “cannot break through the film and kill the bacteria,” thereby allowing it to reach the corneal surface, Prof. Tan said.

“The high polymer content combined with poor product compliance reduces the margin of safety,” he said.

Other noncompliance factors are contact users reusing solution, not rinsing contact lens cases and not cleaning or replacing lens cases.

Terrence P. O'Brien

Executives with B&L agreed with Prof. Tan’s assessment, telling Ocular Surgery News that the formulation issue is “a result of non-compliant behaviors relating to evaporative conditions favoring polymer concentration, such as topping off; not changing solution daily; and not cleaning and replacing the lens case.” In addition, there is a “causal relationship” between film buildup and noncompliant habits. B&L noted that Fusarium found on the tip of a solution bottle with polymer film was one example of the result of a patient not closing the cap after use as directed.

The polymer theory is part of a problem that may also be related to the type of disinfectant molecule specifically used in ReNu with MoistureLoc, said Terrence P. O’Brien, MD. B&L opted to use alexidine in the MoistureLoc formulation. Alexidine is a smaller molecule than the company had previously used, Dr. O’Brien said. The smaller weight meant that absorption into the lens material is prohibited, but that also means the Fusarium bacteria can survive on the surface of the contact lens, he said.

“We don’t just need disinfectants in these solutions, we need biocompatible disinfectants,” he said.

Dr. O’Brien said case control studies are under way at Bascom Palmer Eye Institute in Miami and sites in Singapore and Malaysia.

To date, Prof. Tan has found 68 cases of Fusarium keratitis in Singapore, and 130 confirmed cases around the United States have been reported. An additional 18 cases have been found in Malaysia at one physician’s practice, speakers said.

“I think we still need to clear up issues,” Prof. Tan said. “It is still surprising why there was MoisturLoc use in other countries, which did not have any infections at all, such as throughout Europe. There are still these unanswered questions. We also saw Fusarium keratitis in other contact lens solutions. This could just be ‘noise,’ but I think it’s time to also have a look at how solutions are tested and review the current guidelines.”

“Fusarium keratitis is an emerging disease, and more research must be done,” Prof. Tan said.

Ocular lubricity an overlooked factor in dry eye

Ocular lubricity is an overlooked factor in eye surface health that may provide new opportunities for the use of gel-forming polymers, according to an ophthalmologist.

During an Alcon-sponsored symposium, Michael Lemp, MD, described new concepts that help ophthalmologists to better treat dry eye.

“We must look for agents to stabilize the tear film and protect the ocular surface,” Dr. Lemp said.

Cellular genetics studies are only one novel approach that is currently being studied, he said.

Amniotic membrane transplant effective

Amniotic membrane transplantation is an effective treatment of Mooren’s ulcers, said Chau Thi Minh Hoang, MD. She described a prospective, non-comparative case series of 10 eyes in eight patients with Mooren’s ulcers. Five of the eyes had not responded to other therapies including antibiotics and corticosteroids, and five had recurrent ulcers.

“Amniotic membrane can be used as an ideal graft in a variety of ocular surface diseases,” Dr. Chau said.

The average follow-up was 10 months, and the average patient age was 49.2 years. Four of the eyes underwent a single layer transplant, and the other eyes underwent a multilayer transplant. On average, eyes began healing in 3 days, Dr. Chau said.

At 6 months, three eyes were 20/25, and two were between 20/50 and 20/30, she said. Vision had stabilized by the 6-month mark in all patients, she said.

The procedure is not without its limits, Dr. Chau said, as it is difficult to perform in cases with large perforated ulcers and can leave irregular astigmatism postoperatively.

“Amniotic membrane transplantation may be considered an effective procedure for severe cases of Mooren’s ulcer instead of conjunctival resection or lamellar keratoplasty,” Dr. Chau said.

Cataract Surgery

Phaco, small incision increasingly common

Phacoemulsification and small incision cataract surgery are becoming more common in places such as Nepal, said one physician from that country.

“I see [small incision cataract surgery] with temporal incision as a strong surgical technique coming up in this part of the world,” said Sanduk Ruit, MD, of Kathmandu.

Phaco with foldable IOL implantation is also gaining in popularity, “but we need to address cost factors, training factors and equipment,” he said. “Equipment must be more robust.”

Over the past 10 years, Dr. Ruit and his colleagues at the Tilganga Eye Center developed a sutureless manual extraction cataract technique. He said they remove the entire cataract through a triangular capsulorrhexis constructed with a straight needle.

“You must make the rhexis larger than you would need with phaco to extract the whole nucleus,” he said.

The nucleus is extracted from the eye in two steps, he said, first delivering it into the anterior chamber of the eye and then extracting it from the eye in sections. Dr. Ruit said one of the technique’s advantages is that the surgeon sits in one place throughout the procedure.

In Nepal, Dr. Ruit said, physicians are creating strict guidelines for local ophthalmologists’ training in these types of procedures.

“Microsurgical training should be continuous, wet lab and hands on,” he said. “There should also be mandatory training for 1 year before [trainees] can perform it.”

Dr. Ruit said his Tilganga Eye Center has improved patient flow and treats more difficult cataract cases than some other eye clinics in Nepal. In an effort to treat all patients, Dr. Ruit said his facility uses one physician and five support personnel, a reverse model from the common practice in Nepal. Too many physicians with not enough support staff is “very inefficient,” he said.

“Think of achievable models and don’t get overwhelmed,” he said.

New aspheric IOL

STAAR Surgical recently launched the KS-3Ai aspheric IOL, which features a pre-loaded injection system, according to Hans Blickensdoerfer, vice president of marketing for STAAR Surgical.

The injection system provides sterile delivery, and the aspheric IOL features polyimide haptics to provide stable centration, according to Dr. Blickensdoerfer. The system was launched at APAO.

The lens and pre-loaded injection system have been available in Japan for more than a year and are now available throughout the Asia-Pacific region. They were also recently launched in Europe, company officials said.

Glaucoma

Improved trabeculectomy techniques

Advances in trabeculectomy, including increasing bleb hole sizes and the advent of adjustable sutures, have made the surgery “unrecognizable compared with a few years ago,” said Peng T. Khaw, MD, of London’s Moorfields Eye Hospital. He outlined the technique now preferred at Moorfields.

Peng T. Khaw

Using the most advanced proven techniques has helped “dramatically reduce postoperative complications” such as blebitis, inflammation and endophthalmitis, Prof. Khaw said. As a result, the hospital has reduced the incidence of complications from about 20% to none, he added.

The improvements Prof. Khaw has implemented include controlling fluid flow by directing it posteriorly, using a “much larger area” for creation of blebs and using a 500 µm punch.

“You don’t need special machines for this, you just need a change in technique,” he said. “These are simple changes that people can make tomorrow.”

Adjustable sutures have also radically changed trabeculectomy, significantly reducing postop hypotony, Prof. Khaw said. Currently, there is about a 2% risk of hypotony at Moorfields, a decrease from about 25% before the use of adjustable sutures, he said.

“It’s what we have been dreaming about,” Prof. Khaw said.

Other advantages to using adjustable sutures are that they do not need to be removed and surgeons need to place only enough sutures to control the flow.

Information can improve patient compliance

Physicians must provide patients with “good information” and offer realistic expectations if they want to improve patient compliance with glaucoma treatments, said one physician.

“How we provide information is more important than what we provide,” said Ivan Goldberg, MD, FRCS.

Over a period of 18 months, about 25% of patients will fail to fill a second prescription, he said. He added that 80% of patients either change or discontinue their prescription during those 18 months.

“Missing a single dose can cause a 4.6 mm Hg fluctuation in pressure,” he said at an Alcon-sponsored symposium.

Socioeconomic factors must be considered, Dr. Goldberg said, including lifelong physician visits, long-term costs and intrusive drug regimens.

“Minimizing the number of drugs will positively affect compliance,” he said.

5-FU during trabeculectomy helps keep IOP lower

Use of 5-fluorouracil during trabeculectomy resulted in significantly lower IOP than when surgeons did not use the intraocular injection, a long-term study found.

“This is the largest long-term glaucoma surgery trial in Asia,” said Steve Seah, MD.

Dr. Seah said a similar study is being conducted at London’s Moorfields Eye Hospital.

A total of 235 patients were assigned to either 5-FU (115 patients) or placebo (120 patients) during trabeculectomy. The mean follow-up was 54 months, with patients completing at least 12 months of follow-up, Dr. Seah said. The primary outcomes were postoperative IOP, progressive loss of visual field and loss of optic disc neuroretinal rim area.

Dr. Seah said levels of success were defined as IOP of less than 14 mm Hg, 17 mm Hg or 21 mm Hg on two separate occasions postop. Of the patients in the 5-FU group, 83 had an IOP greater than 14 mm Hg, compared with 101 of the patients in the placebo group. There were 57 patients in the 5-FU group who had an IOP of more than 17 mm Hg, compared with 73 in the placebo group, Dr. Seah said.

There were no significant differences in adverse events between the two groups, Dr. Seah said. He added that there was a slight difference in the number of patients who developed uveitis, but he said the difference was not statistically significant.