Beat the Bug and Inflammation!

Updates on the latest diagnosis and treatment options of infectious keratitis in Asia

by Tan Sher Lynn

Experts from the Asia-Pacific region shared the latest findings from the ACSIKS study, as well as provided updates on the treatment of various forms of infectious keratitis.

Established by the Asia Cornea Society (ACS) in August 2010, the Asia Cornea Society Infectious Keratitis Study (ACSIKS) is a multicenter, prospective, observational study of infectious keratitis in each participating center, conducted over 12 months. “All together we recruited more than 7,300 patients between 2012 and 2019,” said Dr. Khor Wei Boon (Singapore).

“Pseudomonas aeruginosa (P. aeruginosa) was the most common bacterial pathogen isolated in ACSIKS. Multi-drug resistance (MDR) was found in 14% of P. aeruginosa isolates, largely from the centers of India. Some of the fluoroquinolone (moxifloxacin and besifloxacin) had the highest cumulative resistance rates,” shared

Dr. Khor. “This is a concern as topical fluoroquinolone is the antibiotic of choice for the treatment of infectious keratitis. However, fortunately, this data is largely contributed by the high resistance rates in Indian isolates. Outside of India, most of the centers are seeing a much lower rate of drug resistance,” he continued.

Nevertheless, there are limitations to the study. “ACSIKS is conducted in major tertiary eye centers, so infections may be more serious and more likely to be resistant. Nonetheless, we hope that this information will help Asian ophthalmologists in making informed and prudent antibiotic choices in the management of infectious keratitis,” Dr. Khor said.

Novel diagnosis methods

Meanwhile, Dr. Venkatesh Prajna (India) shared about new methods that will help to diagnose fungal keratitis more accurately, including deep learning, fluorescent smart probes, and the lateral flow device.

According to him, clinicians are only able to correctly distinguish bacterial from fungal ethology 66% of the time. On the other hand, computer vision models were able to achieve superhuman performance in identifying the underlying infectious cause of microbiologically positive corneal ulcers, with the bestperforming convolutional neural network (CNN) being the Mobile Net, which attained an AUC of 0.86 on the single center test set.

The fluorescent smart probe offers a comparative method to gram stain for delineating gram-positive or gram-negative bacteria or fungi within corneal scrapes, demonstrating equivalent or higher sensitivity, specificity positive predictive value (PPV), and negative predictive value (NPV) and accuracy than culture to gram stain. “Our approach has scope for point-of-care clinical application to aid in the diagnosis of microbial keratitis,” Dr. Prajna said.

In addition, the lateral flow device can be used to rapidly diagnose Aspergillus keratitis in just 20 minutes.

“There are innovative diagnostic modalities in the anvil, which may reduce the need for an expensive microbiology setup,” he said.

Managing atypical keratitis

Atypical keratitis is caused by an uncommon organism, such as Phythium insidiousum, that is difficult to identify, leading to delayed diagnosis and treatment as well as poor visual outcomes, noted Dr. Vilavun Puangsrich Arern (Thailand).

She described three types of atypical keratitis — Phythium keratitis, Microsporidial keratitis, and Acanthamoeba keratitis

“Atypical keratitis should be suspected in cases with indefinite diagnosis which failed to respond to conventional treatment. Several unique clinical courses and presentations would be clues to suspicion of each causative organism. When in doubt, perform special staining techniques and cultures together with in vivo confocal microscopy (IVCM), polymerase chain reaction (PCR), and corneal biopsy for histopathological examination, which will guide you to the diagnosis and treatment,” she shared.

Updates on microbial keratitis treatment

Keratitis is sight-threatening with one in 10 elderly patients losing an eye and 40% losing vision, noted Dr. Stephanie Watson (Australia). “It is the fifth

Ophthalmologists Discuss Extended Range of Vision with the RayOne EMV IOL

At a packed breakfast symposium today at APACRS 2023, a highprofile panel of ophthalmologists, led by APACRS Past President Prof. Graham Barrett, delved into how the RayOne EMV IOL from Rayner provides patients with an extended range of vision — especially when used with a monovision approach.

In-coming ESCRS President Prof. Filomena Ribiero showed defocus curves from her study comparing Rayner’s EMV IOL with EDOF and monofocal IOLs. The RayOne EMV demonstrated excellent visual outcomes for distance and intermediate vision, and good visual acuity for near vision.

Out-going ESCRS President Prof. Oliver Findl then presented the first multicenter clinical data on the EMV Toric. Results showed significant cylinder reduction, UDVA similar to a standard monofocal IOL, a range of vision extension with excellent UIVA values, and very good functional UNVA outcomes.

Lastly, Dr. Tun Kuan Yeo, senior consultant for the Department of Ophthalmology at Tan Tock Seng Hospital in Singapore, presented his findings comparing clinical outcomes of the EMV with emmetropia and modest monovision. He found good distance and intermediate VA with bilateral emmetropia, as well as good distance, intermediate and near VA with modest monovision. Further, the EMV lens showed similar performance in photopic and mesopic conditions and was pupil size independent.

Prof. Barrett said: “For many years I have worked on optimizing a lens for monovision, given that it accounts for nearly 30% of all surgeries. I collaborated leading cause of blindness worldwide with most of the burden in lowerincome countries. People in those countries where they lose one eye are more likely to lose vision in the other eye,” she added. with Rayner on bringing this lens to market as RayOne EMV, an exciting new product for all surgeons looking to treat presbyopia reliably.”

According to Dr. Watson, more cost-effective community-driven eye care models, effective and safe pharmacological interventions, and educational interventions to enable rapid diagnosis and treatment, as well as preventive eyewear, are needed to tackle the problem.

“To improve outcomes, we need to be able to identify the microbe and choose antimicrobial therapy. Global surveillance will have a key role in this, along with improved regimes and newer antimicrobial agents. Importantly, we need the resources for more research and technology to really advance the field. And while we do this, the public and patients need to be educated that if they get an abrasion, they need to seek help and treatment. Finally, we need to improve our patient experience,” she concluded.