LASIK-dry eye connection gets attention at AAO-PAAO

The joint meeting presented innovative work in all subspecialties from cornea to retina.

ORLANDO, Fla. — About 26,000 physicians, allied health personnel and exhibitors attended the 1999 Joint Meeting of the American Academy of Ophthalmology (AAO) and the Pan-American Association of Ophthalmology (PAAO).

At this year’s meeting, there was an emerging recognition of an important complication of laser in situ keratomileusis (LASIK) — postoperative dry eye.

During his keynote address in a session on LASIK complications and their management at the Refractive Surgery Subspecialty Day, Richard L. Lindstrom, MD, noted that the overall frequency of complications after LASIK is decreasing. Severe vision loss after LASIK is now a rare occurrence.

However, he said, dry eye is being seen with increasing frequency, is making patients very unhappy and must be recognized and treated aggressively. In his practice in Minneapolis, he said, he often uses punctal occlusion to address patient complaints of dry eye.

Roger F. Steinert, MD, echoed these remarks in his address later in the same complications session. He noted that LASIK patients tend to be “self-selected dry eye patients.” That is, many seek LASIK because of contact lens intolerance. He too noted that silicone punctum plugs are being used frequently in his practice.

Marguerite B. McDonald, MD, devoted her entire address during the Late Breaking News segment of the Subspecialty Day to a discussion of this emerging complication. She noted several possible explanations for this phenomenon. These include exacerbation of pre-existing dry eye by the use of multiple medications after LASIK, including steroids; the possibility that previous contact lens use has disrupted normal corneal physiology; and the possibility that hormonal changes from menopause or birth control pills may be to blame in some women.

Other possible explanations take into account the effects of the surgery itself, she said. The microkeratome may damage the cilia and affect the mucous layer of the tear film. Additionally, the cutting of the nerves of the central cornea by the microkeratome may affect corneal sensation, which in turn affects the level of tear secretion, Dr. McDonald said.

Whatever the explanation, the take-home message was that this is a serious, newly recognized complication of LASIK that surgeons should be aware of and ready to address. Dr. McDonald recommended careful preoperative slit lamp examination with rose bengal and fluorescein staining for diagnosis and postoperative treatment with unpreserved artificial tears at least every 2 hours.

Dr. McDonald said she has begun an investigation of ophthalmic cyclosporine 0.05% (Restasis, Allergan) for dry eye after LASIK. She obtained her own investigational drug exemption and is currently investigating the drug’s efficacy in these cases. (Restasis is still awaiting FDA premarket approval.)

Another cause of DLK

--- William S. Tasman, MD, president of the AAO, stood before a standing ovation at the meeting’s Joint Opening Session.

Diffuse lamellar keratitis (DLK), also known as sands of the Sahara syndrome, has been called a multifactorial complication of LASIK, with everything from microkeratome lubricants to improper sterile techniques blamed for its occurrence. At least one clinic has identified a definitive cause of the syndrome. D. James Schumer, MD, said during the Late Breaking News session that in his practice, a desktop sterilization unit has been implicated.

After four occurrences of DLK in which best corrected vision was lost, Dr. Schumer and his staff did a thorough search for possible causes of infection. They found culture-positive Pseudomonas in the reservoir of their desktop sterilizer, even though they had been following the manufacturer’s recommendations for cleaning the unit. After instituting a new regimen of draining the reservoir every night, leaving it to dry overnight and refilling with sterile water the next day, there have been no recurrences of DLK at his clinic, Dr. Schumer said.

“We believe that this problem may be common to most tabletop sterilizers used for LASIK surgery,” Dr. Schumer said.

Retinal complications

---Juan Verdaguer T., MD, president of the PAAO, spoke about his belief in Pan-Americanism at the meeting’s Joint Opening Session.

After review of refractive surgery patients operated upon by the same surgeon, the three predominant retinal pathologies before and after LASIK included peripheral retinal degeneration and/or retinal holes, macular hemorrhage and retinal detachment.

According to the study’s presenter, Jesus S. Vidaurri Leal, MD, the peripheral retinal degeneration or holes were most common. Lattice degeneration was the common type of retinal degeneration, followed by “white without pressure” and other less common degenerative conditions such as pavingstone, snowflake, cystoid and snailtrack retinal degeneration. Macular hemorrhage was seen in a small percentage of myopic eyes, as was retinal detachment.

According to Dr. Leal, the majority of retinal complications seen in this study reflects the natural history of myopia and so cannot necessarily be linked to LASIK.

Taking a stand

William S. Tasman, MD, president of the AAO, received a standing ovation at the meeting’s Joint Opening Session after expressing the opinion that postoperative management of patients by optometrists is usually inappropriate and often no more than fee splitting.

“You [audience] are the EyeMDs,” Dr. Tasman said. “You are the ones that are vastly prepared to give postoperative care to patients. When money becomes the sanctity of what we are doing, then maybe we are in the wrong profession.” Dr. Tasman also warned against the continuing expansion of optometric scope-of-practice legislation, such as optometrists in his native Pennsylvania currently trying to obtain an authorization to use steroids.

Dr. Tasman also received much applause when he recognized the recent reimbursement victory whereby the base-year practice expense provision from the 1997 Balanced Budget Act was dropped. Dr. Tasman expressed thanks to those hundreds of ophthalmologists who contacted their senators on the Finance Committee, urging the removal of the provision. According to Dr. Tasman, ophthalmologists’ efforts prevailed and have saved ophthalmology in excess of $200 million.

In other good news for ophthalmology, Dr. Tasman announced that President Clinton agreed to temporarily retain current “pass-through” payments for corneal tissue processing until further study is conducted. As part of the Hospital Outpatient Department Prospective Payment System proposed rule, the Health Care Financing Administration had proposed that fees for corneal tissue be “bundled” with payments to the facility for the surgery.

PAAO meeting

Following opening remarks and introduction, Dr. Tasman gave his welcoming remarks in Spanish, recognizing the representation of the PAAO.

PAAO President Juan Verdaguer, MD, spoke about the PAAO, his belief in Pan-Americanism and the importance of specialty training in ophthalmology with the help of funding from fellowships. Dr. Verdaguer told the audience that only a minority of Latin American peoples have access to care, and he estimated that out of 475 million, about 1.3 million are blind from cataract alone.

In an effort to prevent continued vision devastation, Dr. Verdaguer and others had designated July 3, 1999 as D-Day, where ophthalmologists devoted 1 work day to screening for diabetic retinopathy.

Later during the Joint Opening Session, the following awards were presented:

Guest of Honor: W. Banks Anderson, MD, of Durham, N.C.; W. Richard Green, MD, of Baltimore; and Robert B. Welch, MD, also of Baltimore;

Distinguished Service Award: H. Dunbar Hoskins, Jr., MD, AAO executive vice president;

Special Recognition Award: Virginia S. Boyce, of New York, and Loretta Drew, of Waukegan, Ill.;

1999 International Blindness Prevention Award: Francisco Contreras, MD, of Lima, Peru; and

Outstanding Humanitarian Awards: Davis G. Durham, MD, FACS, of Wilmington, Del.; Michelle Gelkin, MD, of Baltimore; John B. Jeffers, MD, of Philadelphia; John J. McDermott, MD, of Claremont, Calif.; and Tully C. Patrowicz, MD, of Mount Dora, Fla.

ELK instead of PK?

On the clinical front, Juan F. Batlle, MD, suggested that two successful corneal endothelial transplantations may indicate that the door has been opened to a new alternative to penetrating keratoplasty.

The new procedure, endothelial lamellar keratoplasty (ELK), takes a posterior corneal lamella containing endothelium and transplants it into eyes with endothelial dysfunction such as Fuchs dystrophy.

A corneal flap is first created in the recipient eye using a microkeratome. After lifting the flap, Dr. Batlle uses a trephine to resect the posterior cornea. A donor posterior corneal lamella is then sutured to the recipient cornea and the graft is covered with the flap.

The advantages of the ELK include less pain, less inflammation, reduced astigmatism and short recovery time compared with penetrating keratoplasty.

Intacs, I-tacs for keratoconus, hyperopia

Joseph Colin, MD, of Brest, France, reported on use of Intacs (KeraVision; Fremont, Calif.) intrastromal corneal ring segments for treatment of keratoconus. He now has 10 keratoconus patients in whom he has implanted the Intacs. It makes more sense, he said, to reinforce the thinning corneas of these patients with the plastic ring segments than to weaken them with a tissue removal procedure such as photorefractive keratectomy (PRK) or LASIK, as other surgeons have suggested.

The keratoconus procedures are identical to normal myopic Intacs implantations, he said, except that the implantation site is moved 90°, so that the segments have a horizontal rather than vertical orientation. The procedure does not eliminate the disease, he said; it just reshapes the cornea.

KeraVision’s other product, corneal implants for hyperopia correction known as I-tacs, were discussed by Kerry Assil, MD. He said Arturo Chayet, MD, has implanted the devices in 16 eyes of patients in Mexico. The 2-mm segments, implanted radially around the cornea, have provided stable correction of low hyperopia for up to 18 months. Several patients have had one or more of the segments removed to demonstrate the reversibility of the procedure, Dr. Assil said.

Intacs stable

Additionally, clinical trial data submitted to the Food and Drug Administration show that Intacs are effective in correcting mild myopia and are safe, well-tolerated in the eye and stable over time, said David J. Schanzlin, MD, professor of ophthalmology at the University of California in San Diego and chief medical investigator for the Intacs clinical trials.

Intacs showed stable correction 2 years after treatment with 76% of treated eyes seeing at least 20/20, 55% seeing 20/16 or better and 21% seeing at least 20/12. Two-year clinical results were based on 358 treatments performed at 11 medical sites as part of phase 2 and phase 3 studies. Patients were treated for 1 D to 3 D of myopia.

Analysis shows that wavefront analysis of Intacs eyes are consistent with quality vision, Dr. Schanzlin said.

“We believe this occurs because Intacs, unlike laser procedures, preserve the natural shape of the cornea, which appears to be a critical element of overall quality of vision,” he said.

Most Intacs removals (86%) were for problems that potentially could be fixed by replacement with another Intacs size, including visual symptoms, astigmatism and undercorrections and overcorrections. Only 0.1% of cases were safety-related out of a total removal rate to date of 6% of Intacs treatments, Dr. Schanzlin said.

Glaucoma screening device

Laser Diagnostic Technologies (LDT, San Diego, Calif.) launched a new version of its GDx nerve fiber layer analyzer at the AAO meeting. The GDx Access is a portable version of the GDx machine, capable of measuring the nerve fiber layer of a patient in 1 second through an undilated pupil. The Access will not be sold, but rather will be placed in practitioners’ offices for a small installation fee — one-tenth the price of the original GDx, according to LDT — and its software will be continuously upgraded. Physicians will be charged a fee per exam.

The company noted that there is now a current procedural terminology code for use of the GDx, and this same code can be used with the GDx Access.

“Measuring eye pressure has been pivotal in glaucoma screening, but by measuring the thickness of the nerve fiber layer, we may detect glaucoma in its earliest stages, permitting treatment before major damage occurs,” said Gavin Bahadur, MD, in a statement released by LDT.

Laser photocoagulation still alive

Although photodynamic therapy (PDT) is making all the headlines, conventional retinal laser photocoagulation is not dead, according to Stuart L. Fine, MD. Dr. Fine said that extrafoveal neovascular lesions and recurrences that remain extrafoveal should be treated with laser photocoagulation. This includes those recurrences that are subfoveal, according to data from the Treatment of Age-Related Macular Degeneration (AMD) with Photodynamic Therapy Trials. Additionally, in normotensive patients, juxtafoveal neovascular lesions and subfoveal recurrent neovascular lesions should be treated with laser photocoagulation, according to Dr. Fine.

More data still are needed before a recommendation for laser photocoagulation versus PDT can be made, according to Dr. Fine. For instance, the Macular Photocoagulation Study Group has published 5-year outcome data comparing treated versus untreated eyes, whereas only 12-month data on PDT are available, making it difficult to compare the relative effectiveness of the two therapies.

Feeder vessel identification with ICG

Occult choroidal neovascularization (CNV) in patients with AMD is difficult to treat due to the uncertainty of its borders on fluorescein angiogram, but better treatments may be emerging.

In a study presented by Bert M. Glaser, MD, patients with occult CNV were viewed by biomicroscopy, fluorescein angiogram and high-speed indocyanine green (ICG) videoangiography. All were treated with an 810 nm diode laser, occasionally with ICG enhancement of the vessels. Closure of vessels was successful with one treatment in some patients, with most requiring more than one treatment in order to have resolution of the subretinal fluid. In some instances, the vessels did not seal. Visual improvement, according to Dr. Glaser, was usually within hours postoperatively, while others gained vision several weeks postoperatively.

AMD progression after cataract surgery

Ayala Pollack, MD, described the progression of AMD after cataract surgery in three groups of patients with dry early AMD. Dr. Pollack compared two different groups of patients. One group consisted of 47 patients with bilateral similar moderate dry AMD and bilateral aphakia who had undergone unilateral surgery. The course of maculopathy was compared in the operated and the non-operated eyes. The second group of 33 patients had undergone unilateral cataract surgery with a stable postoperative course of maculopathy in the operated eye for at least 1 year and subsequently underwent cataract surgery in the fellow eye.

In group 1, Dr. Pollack reported that wet AMD occurred in 19.1% of operated eyes and in 4.3% of non-operated fellow eyes. Acute wet AMD occurred in two peaks during the follow-up period, in 44.4% of eyes within 3 months of surgery and in 44.4% within 6 to 12 months. Male gender and soft drusen were found to be risk factors for progression.

In the second group, 27.2% progressed to wet AMD, of which 3% was in both eyes and 24.2% in the second eye only. The condition of two of the first operated eyes deteriorated after the operation on the second eye.

In a third group, YAG capsulotomy was examined. Out of 24 patients, 12.5% developed wet AMD within 1 year.

PRK is safe with the Visx Star

Effective treatment for mild to moderate hyperopia and hyperopic astigmatism was achievable with PRK using the Visx (Santa Clara, Calif.) Star excimer laser, according to a poster presentation by W. Bruce Jackson, MD.

The excimer laser was used on 123 eyes that were separated into three groups based on the extent of the patients’ hyperopia. Group 1 contained 78 patients with low hyperopia of +1 to +4 D SE. The moderate hyperopia group consisted of 21 patients with +4 to +6 D of SE. Twenty-four patients had hyperopic astigmatism up to +6 D sphere with +0.5 to +3.25 D cylinder. All patients were followed for 12 months to 36 months.

Ninety-six percent of low and 75% of moderate hyperopes achieved best corrected visual acuity of 20/40 or better by 12 months. Hyperopic astigmatic patients had a mean spherical equivalent (SE) of –0.02 ±0.71 D. Mean SE 24 months after surgery for patients with low hyperopia was +0.12 D ±0.44 D and +0.4 ±0.92 D for moderate hyperopic patients, respectively.