Laser vision correction turns the big 3-0

By Marguerite B. McDonald, MD

March 25, 2018 marked the 30th anniversary of the first laser vision procedure in the world, a PRK, on a live subject. I had the honor of performing it. For me the journey began in 1983 when I read, with fascination, Steve Trokel’s ground-breaking AJO paper¹ in which he used an industrial excimer laser to make patterns in cadaver animal eyes. In 1984, Charles Munnerlyn, PhD, Steve Trokel, MD, and I began our long journey to develop laser vision correction. We ablated thousands of plastic test blocks, then cadaver animal and human eyes, then living rabbit eyes, then living monkey eyes, refining the hardware, software and surgical technique over the years. Steve Klyce, PhD, was also an important member of our research team.

IT WASN’T A SURE THING THEN

Progress was arduous. One step forward, two steps back. We lost staff, we had poor results early on.

The roughest obstacle: conquering the haze. Initially we had no idea why we were getting haze. In fact, it was the reason I lost a research coordinator and technician — the rabbits’ eyes developed such severe subepithelial haze that they thought the project was going nowhere.

LIGHT BULB MOMENT

We then made an intuitive leap; if we smoothed the ablations some more, that might help. So we increased the number of steps in the closing diaphragm and automated this process (I had been cranking the diaphragm closed by hand!). So, having started at five steps, we increased to an automated 40-step ablation — and the haze problem improved dramatically.

[N.B.: Of course, later, we went on to put many dozens of steps into the ablation program and much later added flying spot treatments (possible only when high fidelity trackers were introduced). These improvements made the haze virtually a nonissue.]

A GENEROUS GIFT

Then an extraordinary opportunity presented itself, in the form of Mrs. Alberta Cassady. This 62-year-old woman had cancer of the orbit, requiring exenteration. With a massively disfiguring procedure looming and a poor prognosis even with the surgery, she offered to let us do experimental surgery on her eye. We knew we would get her eye as part of the exenteration tissue block.

Since time was of the essence, the FDA allowed us to rush Mrs. Cassady past the monkey cages at the Delta Primate Center in Covington, La. (the vivarium used by LSU Eye Center). On March 25, 1988, I performed the world’s first laser vision procedure on a living human subject. We watched her heal on a daily basis, right up until the exenteration 11 days later. The pathology report showed the healing pattern that we now know so well.

Mrs. Cassady lost her battle with cancer. Her remarkable bravery and generosity in the face of such tragedy gave us vital information that allowed the FDA to accelerate the approval process. Though only wealthy donors have facilities named after them, we demanded that LSU allow us to name the laser facility after her.

The FDA was so impressed by the daily postop evaluations and histological specimen that it allowed us to start the blind-eye trial immediately instead of requiring months, maybe years, of additional monkey experiments.

And the rest is history. OM

REFERENCE

1. Trokel SL, Srinivasan R, Braren B. Excimer laser surgery of the cornea. AJO. 1983. 96:710-175.

An Atlas to take glaucoma imaging forward

By René Luthe, senior editor

Heidelberg Engineering has launched its Glaucoma Imaging Atlas, a textbook that will serve in the company’s OCT educational initiative. Heidelberg wants to help ophthalmologists make advanced use of OCT information in glaucoma diagnosis and management.

According to the company, in-person observations at clinics worldwide led to the conclusion that, in about 20% of glaucoma cases, OCT parameters do not agree: not with one another, with visual field results and/or with clinical examination results. “The Glaucoma Imaging Atlas illustrates that careful review of OCT images, in addition to more relied-upon summary metrics, is the key to reducing the uncertainty that presents in these … cases,” says a Heidelberg representative.

The Atlas is meant to help users consider OCT results in the management of either routine or challenging cases that may present with confounding factors. Heidelberg says its Atlas also includes supplemental information describing the premise behind the Spectralis Glaucoma Module Premium Edition. This information includes the rationale behind the diagnostic parameters, the associated reference databases and how the available glaucoma reports should be evaluated.

The cases and their partnered educational workshops show that OCT images and the associated parameters should be interpreted in conjunction with other routinely collected clinical data (such as visual fields, IOP, central corneal thickness, family history and so on). The company plans workshops to educate users on correctly interpreting the content of the Atlas. Each copy of the Atlas will be accompanied by Heidelberg Engineering’s Heyex viewing software, which includes the cases (with fundus photos and visual fields), allowing for interactive review of cases.

Alex Huang, MD, PhD, was one of 27 clinicians who contributed a glaucoma case study to the Atlas. The images were taken with Heidelberg’s Spectralis, its Glaucoma Module Premium Edition. Dr. Huang, an assistant professor of ophthalmology at the University of California, Los Angeles, said this glaucoma analysis tool helped with his “clinical decision making and management of glaucoma. [The Spectralis] combines high-quality images with user-friendly summary metrics.” OM

Link found between cataracts, asthma, allergy

By Robert Stoneback, associate editor

A new study that found an association between cataracts, asthma and allergic rhinitis (AR) should prompt ophthalmologists to more thoroughly investigate patient complaints of allergy and asthma, says AAO spokesperson John Hovanesian, MD. As such conditions are frequently the first touchpoint between patient and physician, they should not be quickly dismissed as they may be the preliminary signs of something worse, explains Dr. Hovanesian, who also serves as a clinical faculty member at the UCLA Jules Stein Eye Institute.

The South Korean study, published in January’s Journal of Dermatology,¹ examined data from 14,776 people using a nationwide health survey conducted by the Korean Centers for Disease Control and Prevention. The goal of the authors was to analyze any association between allergic diseases and ophthalmic diseases.

According to the study authors, ocular diseases, including glaucoma and cataracts, have previously been associated with topical and inhaled corticosteroid use, such as the kind used to treat allergic diseases. A link between atopic dermatitis (AD) and the development of cataracts and glaucoma was also researched in the study, as AD, AR and asthma are all treated with glucocorticoid therapy; an association with AD and these ocular diseases was not found, however.

HAZARD RATIOS

When other factors, such as age, sex and health were accounted for, patients with asthma were found to be 50% more likely to have cataracts than those in the nonhazard group, with the asthmatic patients having a hazard ratio of 1.51, according to the study. Those in the allergic rhinitis group had a similar cataract hazard ratio, 1.565.

Further analysis would be needed to better understand the relationship between these factors, wrote the study authors. The most plausible explanation offered for this correlation between asthma and cataracts was the asthmatic patients’ older age, according to the authors. They speculate that the AR patients’ use of corticosteroids in the nasal cavity could explain the increased risk of cataracts.

A separate study,² published on the website PLoS ONE in November 2016 and also from South Korea, found that increased levels of immunoglobulin E (IgE) were independently associated with age-related cataracts, specifically nuclear cataracts. Immunoglobulin E is an antibody that aids the body’s signaling response to allergens. The PLoS ONE study noted that further investigation into their topic would be needed.

ALLERGIES AS INDICATORS

While the findings presented in the Journal of Dermatology shouldn’t cause physicians to change patient treatments, it should urge greater caution, says Dr. Hovanesian.

If doctors treat allergies as “just a runny nose” or “just a rash,” they may miss it as an indicator for a more serious disease; similarly, asthma should not be quickly dismissed either, and patients with asthma or allergies should be checked for signs of cataracts.

Dry eye was once considered “just a nuisance,” but is now seen as an important disease and treated more seriously, Dr. Hovanesian notes. “I would purport that the same is true of allergies.” OM

REFERENCES

1. Lee YB, Lee JH, Kang MJ, et al. Association between allergic diseases and ophthalmologic diseases, including cataracts and glaucoma, using the Korean National Health and Nutrition Examination Survey: 2010-2012: A STROBE-compliant article. J Dermatol. 2018 Jan 4. doi: 10.1111/1346-8138.14193 [epub ahead of print].
2. Yoo TK, Kim SW, Seo KY. Age-Related Cataract is Associated with Elevated Serum Immunoglobulin Levels in the South Korean Population: A Cross-Sectional Study. PLoS One. 2016;11:e0166331.