Proper planning, precautions allow safe cataract surgery in IFIS cases

ROME – Eliciting a history of alpha-blockers allows cataract surgeons to anticipate intraoperative floppy iris syndrome and take measures to effectively deal with the condition, according to a surgeon speaking here at the OSN Rome Symposium.

David F. Chang, MD, gave the Benedetto Strampelli Medal Lecture at the symposium. He focused his talk on strategies surgeons can use either alone or in combination for the management of intraoperative floppy iris syndrome (IFIS). Surgeons should gain experience with several approaches and consider the variability of IFIS severity when deciding how to proceed, he said.

“Stopping tamsulosin (Flomax, Boehringer-Ingelheim) preoperatively is of unpredictable and questionable value, as there are many documented cases of IFIS occurring up to several years following drug cessation,” Dr. Chang said.

Preoperative application of atropine is also often ineffective for moderate and severe cases of IFIS, he noted.

Direct intracameral injection of alpha agonists, such as phenylephrine and epinephrine, can further dilate the pupil. Such drug injections can also restore iris rigidity by increasing iris dilator smooth muscle tone.

Regarding general surgical principles, Dr. Chang advised that surgeons pay close attention to properly constructing incisions and performing gentle, slow hydrodissections. He also recommended using lower irrigation and aspiration flow parameters.

Bimanual microincision surgery may be helpful because its irrigation currents can be isolated within the anterior chamber, which results in less billowing and iris prolapse, he said.

Avoiding or reducing iris prolapse is particularly important and should be considered when selecting a viscosurgical device. Disposable pupil expansion rings are “costly, but 100% effective,” Dr. Chang said, noting that iris retractors are also reliable and should be placed in a diamond configuration.

“The subincisional hook retracts the iris downward and out of the phaco tip path, maximizing exposure in front of the phaco tip, while the nasal hook facilitates chopper placement,” he said.

In his experience, it is easier and safer to insert iris retractors and pupil expansion rings before capsulorrhexis initiation, Dr. Chang added.

The OSN Rome Symposium is a meeting held jointly by Ocular Surgery News, the Italian Association of Cataract and Refractive Surgery and the Italian Society of Ophthalmology. These items appeared originally as daily coverage from the meeting on OSNSuperSite.com. Look for more in-depth coverage of these and other topics in upcoming issues.

Surgeons: Femtosecond lasers can allow thin-flap LASIK

The potential for creating thin LASIK flaps in the 90-µm to 100-µm range represents one advantage to using femtosecond lasers during LASIK, according to surgeons.

“Thin-flap LASIK preserves biomechanical corneal integrity and leaves more stroma for the ablation, reducing the risk of post-LASIK keratectasia,” Michael C. Knorz, MD, said.

Richard L. Lindstrom

Thin-flap LASIK was abandoned in the early days of the procedure because of flap complications such as folds, striae and irregularities. But femtosecond laser technology allows for more precise flap creation with lower risks for such complications.

“We can obtain perfect flaps of 80 µm to 120 µm,” Richard L. Lindstrom, MD, Global Chief Medical Editor of Ocular Surgery News, said.

According to studies presented by both surgeons, flaps created using femtosecond lasers can allow for “optimal” visual quality and are associated with significantly fewer flap-related complications than with microkeratome-created flaps.

Alternatives to Goldmann tonometry useful in certain cases, specialist says

Goldmann applanation tonometry remains the gold standard for measuring IOP, but the Tonopen applanation tonometer and the Pascal Dynamic Contour Tonometer should be used in specific cases, according to a glaucoma specialist.

Antonio Fea, MD, said that Goldmann tonometry is still “the most reproducible system,” but its precision may be affected by irregular astigmatism, corneal scars, corneal edema and reduced corneal thickness.

“For this reason, applanation tonometry might not be entirely reliable in post-refractive surgery patients,” Dr. Fea said.

Pascal tonometry (Ziemer Ophthalmic Systems) is less reproducible, but also less sensitive to corneal thickness. Therefore, it seems more accurate after LASIK or PRK and in ectatic corneas, he said.

“However, we must take into account that it is more difficult to use and requires more cooperation from patients,” Dr. Fea noted.

Although automated and less sensitive to the influence of corneal thickness, the Tonopen (Reichert) is also less reproducible than Goldmann tonometry, and the device tends to overestimate IOP in the extreme ranges. However, the Tonopen requires less patient cooperation and may be better for use in children and post-keratoplasty patients.

Glaucoma shunt promising for managing IOP, surgeons say

The Solx Gold Shunt is a promising new device for glaucoma control, according to a panel of surgeons.

Marco Nardi

“We are at a turning point in the treatment of glaucoma,” Marco Nardi, MD, said. “Thanks to this new implant, we can rely on aqueous outflow in the suprachoroidal space, which is more easily accessible.”

The Solx Gold Shunt implant is a flat plate that measures 3-mm wide and 6-mm long. The device features numerous microtubular channels that bridge the anterior chamber and the suprachoroidal space to help control aqueous outflow and reduce IOP. It is virtually undetectable by the patient and is intended to last indefinitely.

“Aqueous from the anterior chamber enters the ingress holes of the shunt. [It is then] directed through the internal micro-channels and exits the shunt into the suprachoroidal space,” Shlomo Melamed, MD, said.

The device is implanted under topical anesthesia through a small scleral incision about 2.5 mm from the limbus. It is placed in a pocket in the suprachoroidal space and sutured.

The shunt is made of thin, pure gold and is therefore delicate. Thus, surgical maneuvers must be performed gently to avoid scratching or distorting the device.

“We have obtained encouraging results, with a significant and stable decrease of intraocular pressure. All patients have been able to reduce medications significantly,” Dr. Nardi said.

“We have had no complications apart from early, transient hyphema. Eyes are very quiet, and there is no bleb,” Dr. Melamed said.

‘Vaseline’ vision dysphotopsia reported in 3.66% of ReSTOR IOL patients

Severe “Vaseline” vision dysphotopsia occurred in 3.66% of eyes implanted with Alcon’s AcrySof ReSTOR multifocal IOL, according to a study.

The reasons why the ReSTOR lens produced this complication in some patients remains unknown, but it may be correlated with the crowded concentration of diffractive rings in the central 3.6-mm optic, Frank A. Bucci Jr., MD, said.

Patients who experience the condition complain of waxy, hazy vision occurring immediately after implantation and, unlike halos and glare, does not decrease with neuroadaptation, he said.

“Once the lens is explanted, patients experience an immediate relief, despite the temporary increase in their residual refractive error,” Dr. Bucci said.

In a study involving 300 patients implanted with the lens, 13 patients experienced the complication and nine of these patients required explantation, he said.

Surgeon: Blue-blocking IOLs may damage vision and health

Blue-blocking IOLs have no proven advantages for the eye and may cause such conditions as depression, insomnia and other health problems correlated with the disruption of circadian rhythmicity, according to a specialist.

“Blue light is essential for good vision and health,” Martin Mainster, MD, said. “Blue light-sensitive retinal ganglion cells synchronize the human body’s master biological clock to environmental day-night cycles, assuring the proper hormonal and physiological rhythms.”

He emphasized that no evidence has been found of a correlation between blue light exposure and the pathogenesis of either degenerative retinal disorders, such as age-related macular degeneration, or uveal melanoma.

Additionally, blue light provides 35% of rod-mediated scotopic sensitivity and is therefore essential for effective vision in dim light, Dr. Mainster noted.

Corneal inlay simple, effective for presbyopia correction

The AcuFocus ACI 7000 corneal inlay is a simple, safe method for correcting presbyopia up to 1.5 D, providing enough correction “to make 45- to 60-year-olds happy,” Dr. Lindstrom said.

The ACI 7000 is a small disc with a central hole. The device is placed under a LASIK flap and is designed to increase depth of focus through a “pinhole effect,” Dr. Lindstrom said.

Compared with other methods of presbyopia correction, the ACI 7000 has the advantage of being a reversible, minimally traumatic technique that can be carried out under topical anesthesia.

Data from two multicenter studies carried out in Turkey and the European Union demonstrated that emmetropic presbyopic patients implanted with the device retain distance vision and improve both intermediate and near vision. Most patients achieve 20/20 and J1, Dr. Lindstrom said.

European regulatory approval is expected in about 1 year, he said.

New software simulates phakic IOL distances before implantation

Camille J. Budo Jr.

New software for Carl Zeiss Meditec’s Visante OCT (ocular coherence tomography) device will allow surgeons to simulate phakic IOL distances intraocularly before proceeding with surgery, Camille J. Budo Jr., MD, said.

The new software integrates standard anterior segment OCT images of the patient’s eye with a virtual insertion of the desired phakic IOL. The device can then measure all distances, including clearance, vaulting and crystalline lens rise, as they would after actual lens implantation, Dr. Budo said.

“This software will become for us a routine examination, just like topography for the corneal refractive surgeon,” he said.

Surgeon: Customize multifocal IOL choice to best suit patient needs, lifestyles

Because diffractive and refractive multifocal IOLs have different optical properties, use of such lenses “either alone or combined” should be based on patients’ individual needs, according to a surgeon.

In addition, careful patient selection is crucial for achieving good results with multifocal IOLs, Dr. Knorz noted.

According to Dr. Knorz, there are basically three types of multifocal IOL patient candidates.

“The first is ‘the golf player,’ a patient with predominantly distance vision tasks who occasionally uses a laptop and rarely reads a book,” he said. “This patient will have best results with a distance-dominant IOL, such as the ReZoom (Advanced Medical Optics) in both eyes, and may require glasses for reading.”

He described the second type of patient as “the librarian,” someone who rarely drives at night and rarely uses a laptop, but who spends several hours reading books each day.

“A diffractive multifocal IOL like the Tecnis (AMO) in both eyes is the best option,” he said. “[Near] vision will be perfect in any lighting condition [and] distance vision is still good, while intermediate vision is somewhat reduced.”

However, most patients are in between these two extremes and want the best possible vision for a variety of tasks, including reading, driving, playing golf and using a laptop. For these patients, mixing and matching IOLs is the best option, Dr. Knorz said.

Michael C. Knorz

“They should receive a refractive multifocal IOL like the ReZoom in the dominant eye and a diffractive multifocal like the Tecnis in the nondominant eye,” he said.

Ideal candidates for multifocal IOLs include all presbyopic hyperopic patients, followed by patients with 6 D or more of myopia and patients with both presbyopia and cataract, he noted.

“When in doubt, test the patients preoperatively with multifocal contact lenses,” he added.

For surgery, Dr. Knorz prefers to implant in the patient’s dominant eye first, implanting a ReZoom IOL and then asking the patient to evaluate his near vision after surgery.

“If they are happy with their near vision, I implant a ReZoom also in the second eye. If they are not [happy], I implant a Tecnis,” he said.

Because multifocal IOLs only work if the patient achieves emmetropia, laser vision correction can be performed to treat residual refractive errors, he said, noting that multifocal IOL implantation and customized laser refractive surgery can be offered as a package to selected patients.

Two-stage capsulorrhexis may be necessary in some cases

Performing a two-stage capsulorrhexis can help reduce the risk of complications when performing difficult cataract surgery, according to Dr. Chang.

The two-stage approach involves initially creating a capsulorrhexis of a smaller diameter, which can then be enlarged after IOL implantation, he said

“Successful completion is the priority, rather than size,” he said.

According to Dr. Chang, the safest time to enlarge the capsulorrhexis is after IOL insertion because, without the nucleus, the red reflex is improved, which allows optimal visualization of the capsule. Also, there is no convexity in the anterior capsule and therefore less risk of radial, “downhill” tears. In addition, the stiff PMMA haptics of the IOL exert outward pressure against the capsular fornices, similar to a partial tension ring.

“This is particularly important in the case of weak zonules,” Dr. Chang said, noting that the IOL optic can also serve as a convenient template for guiding the continuous curvilinear capsulorrhexis.

Finally, the risks posed by an errant tear are minimized at this point because the most forceful surgical steps have been completed, he said.

A note from the editors:

To facilitate bringing news to readers rapidly, for OSN SuperSite articles and meeting wrap-up articles, OSN departs from its editorial policy and typically does not send these items out for source corrections.