At Press Time
Comparing DSAEK Insertion Techniques
Two studies could influence corneal transplantation.
By Jerry Helzner, Senior Editor
■ When Mark Gorovoy, MD, of Fort Myers, Fla., created the corneal transplantation procedure known as Descemet's stripping automated endothelial keratoplasty (DSAEK), he advanced the treatment of such diseases as Fuchs' endothelial dystrophy, pseudophakic bullous keratopathy and other corneal diseases that can be effectively treated with a partial-thickness graft.
However, in recent years, transplant surgeons and device manufacturers have attempted to improve on the basic DSAEK procedure by developing inserters and injectors to place the donor tissue into the eye. Two new studies presented at the recently completed ARVO meeting shed light on DSAEK insertion techniques. One study compared basic techniques that do not require an inserter while another compared procedures performed with traditional forceps insertion to DSAEK performed with a commercial inserter.
In the first study, researchers from the University of Michigan compared outcomes from 100 eyes of 100 patients who underwent DSAEK. Of the 100 eyes, 51 eyes received the so-called “taco” insertion technique, 19 received the “push” technique and 30 were done with the “pull” insertion technique.
Researchers found no differences in BCVA at six months and one year postoperatively when comparing all three techniques. The BCVA improved significantly in the first six months postoperatively in all three groups, with no significant change from six months to one-year postoperatively. A statistically significant hyperopic shift of 0.86 D was observed, with no difference in the shift across the three groups. There was no significant astigmatic change at any time point. A comparison of postoperative complication rates revealed similar donor dislocation rate of 19% amongst all three techniques.
The researchers concluded that “all three techniques for donor disc insertion in DSAEK are equally effective at all postoperative time points with similar visual acuity outcomes. The techniques result in a similar hyperopic shift and are astigmatically neutral. Additionally, dislocation rates are similar amongst the three techniques.”
In the second study, presented by researchers from Wills Eye Institute, 284 eyes underwent DSAEK using a traditional forceps insertion technique and 124 eyes underwent the procedure with the Neusidl corneal inserter (NCI). Preoperative endothelial cell counts on the donor tissue were provided by the eye banks using confocal microscopy.
Mean endothelial cell counts at three months were 1523 cells/mm2 and 1747 cells/mm2 with traditional and NCI insertion techniques, respectively. Mean endothelial cell counts at six months were 1448 cells/mm2 and 1675 cells/mm2, respectively. At one year, the endothelial cell counts were 1369 cells/mm2 and 1595 cells/mm2, respectively. Mean endothelial cell loss at three months was 1685 cells/mm2 with the traditional forceps technique and 1395 cells/mm2 with the NCI.
The researchers concluded that “corneal endothelial cell loss in donor grafts during DSAEK with the NCI is less than with traditional forceps insertion. The endothelial cell counts in the NCI group remain higher than in the traditional group throughout the first year.”
Though the NCI was used in this study, there are several other inserters and injectors that can be used in the DSAEK procedure.
Racial Patterns in Express Shunt Failures
Study: Many more fail in African Americans.
■ A study conducted by researchers at SUNY Downstate in Brooklyn, NY and presented at the recent ARVO meeting indicates a much higher rate of first-year and overall failure of the Express mini-shunt for African Americans than Caucasians. This was the first study to monitor long-term Express failure based on race.
In this retrospective analysis, 64 eyes of 55 African-American patients and 44 eyes of 35 Caucasian patients with open-angle glaucoma were compared. All were implanted with a subscleral Express mini-shunt with mitomycin C by a single surgeon.
Researchers reported that mean age was 71 and 76 for African-American and Caucasian patients, respectively. Mean length of follow up was 23.3 months for African-American patients and 23.5 months for Caucasians.
Success was defined as an IOP less than or equal to 18 mm Hg with or without additional glaucoma medications. Mean preoperative IOP was 27 mm Hg and 30 mm Hg in African-American and Caucasian eyes, respectively. Mean postoperative IOP was 13 mm Hg and 12 mm Hg in African-American and Caucasian eyes, respectively.
Fourteen African-American eyes failed within one year and 24 failed overall, with 10 of the eyes failing within six months. Only two of the Caucasian eyes failed within one year and 15 overall. Using the Kaplan-Meier survival analysis, the rate of failure within the first year was 22% for African-American patients and 5% for Caucasians.
The researchers concluded that “we found a definite pattern of failure between African-American and Caucasian patients, suggesting that not only do African Americans have a higher rate of failure but also tend to fail much earlier than Caucasian patients. Based on these findings, a prospective study looking at methods to decrease earlier failure in African-American patients may be useful.”
Saving Eyesight at Walter Reed
Positive outcomes in a majority of military-injury cases.
■ From 2003 until 2009, Walter Reed Hospital treated 783 eyes of 574 military beneficiaries for ocular trauma, with the great majority of these injuries related to combat in Iraq and Afghanistan.
The average age of the patients was 27.2, with closed-globe injuries comprising 347 eyes (44%) and open-globe injuries occurring in 289 eyes (37%). Intraocular foreign bodies were present in 118 eyes with open-globe injuries, while perforating injuries occurred in 74 eyes. Simple penetrating injuries occurred in 41 eyes, while blunt-force globe ruptures occurred in 54 eyes. Orbital or eyelid injuries were present in 421 eyes while neuro-ophthalmic injuries occurred in 176 eyes.
In total, 336 surgical procedures were performed on 237 patients. At final follow-up, 425 patients (54%) achieved 20/40 or better visual acuity. Eighty-nine eyes (11%) were enucleated at final follow-up, and 19 patients (3%) were bilaterally legally blind at final follow-up.
The researchers, led by Marcus H. Colyer, MD, found that nearly 10% of all combat casualties between 2003 and 2009 sustained ocular injury, with nearly half of those patients treated at the Walter Reed Army Medical Center.
“Fortunately, the majority of patients retained excellent vision, yet devastating ocular injuries still occur. Improved tracking and longer follow-up is essential to measure long-term effects of these injuries and improve outcomes for patients,” the researchers concluded.
The research was presented at the recent ARVO meeting.
Good Results With Artificial Corneas
The Boston KPro restores useful sight in many cases.
■ Three new studies measuring the effectiveness of the Boston KPro artificial cornea, presented recently at ARVO, indicate that the keratoprothesis can restore a significant amount of sight in cases where grafts have failed or where severe corneal damage has caused devastating visual deficits.
► In one study, researchers at the University of Alabama-Birmingham and Harvard Medical School studied KPro outcomes in 23 eyes of non-autoimmune patients at high risk for primary or repeat corneal transplants.
The 23 eyes had an average of 2.22 prior grafts and an average follow up of 11.7 months after KPro transplantation. Preoperative diagnoses included failed keratoplasty (17), failed perforated graft (4), bullous keratopathy with extensive anterior synechiae (1), congenital glaucoma (1) and aniridia (1).
Preoperative BCVA was ≤ count fingers in 91% eyes. Postoperative BCVA, obtained at an average of 3.1 months, was ≥ 20/40 in 35% eyes and ≥ 20/70 in 74% eyes. Visual recovery was maintained throughout the postoperative clinical course with five patients followed >20 months, and 60% of those patients retaining BCVA ≥ 20/60. Factors associated with a poorer postoperative visual outcome included preoperative retinal disease and preoperative or worsening glaucoma. Intraoperative pars plana shunt or shunt revision was associated with a better postoperative visual outcome. Overall, there was a 100% graft retention rate with no cases of endophthalmitis.
The researchers concluded that the KPro “yields substantial improvement in visual rehabilitation to non-autoimmune patients who may otherwise be poor candidates for repeat or primary penetrating keratoplasty. Visual recovery is rapid and sustained with a high rate of graft retention; however, preoperative retinal disease or glaucoma may limit patients' clinical success. Perioperative treatment of glaucoma may lead to better outcomes. Graft retention and infection should not be considered barriers to successful transplantation in these patients.”
► In a second study, researchers at the Department of Ophthalmology and Visual Sciences at the University of Iowa conducted a retrospective chart review of all KPro-1 procedures at a tertiary care eye center over a 31-month period. All cases with more than three months of follow up were included in the statistical analysis. Outcome measures were graft retention, visual acuity and complications.
Thirty-seven eyes met the inclusion criteria. The indications for KPro-1 were failed graft in 28 eyes, Stevens-Johnson syndrome in three eyes, corneal scar in three eyes, neurotrophic keratopathy in two eyes, and ocular cicatricial pemphigoid in one eye. Graft retention occurred in 36 eyes during a mean follow-up period of 32 months. There was a statistically significant improvement in the mean logMAR BCVA from 1.704 (range, 0.40 to 1.90) preoperatively to 1.32 (range, −0.07 to 1.90) at the most recent examination. A final BCVA of ≥ 20/20, ≥ 20/40, or ≥ 20/200 was obtained in two eyes, 12 eyes and 26 eyes, respectively. Overall, the BCVA improved in 29 eyes, remained the same in four eyes and worsened in four eyes.
One or more major complications occurred in 20 eyes. These included epiretinal membrane (9), escalation of glaucoma therapy (8), cystoid macular edema (8), retroprosthetic membrane (6), retinal detachment (4), and endophthalmitis (1). These complications were responsible for the four eyes which experienced worsened postoperative vision.
The researchers concluded that “the use of the KPro-1 is a viable alternative for eyes with a poor prognosis with conventional keratoplasty. Although sight-threatening complications are common, most eyes retain the keratoprosthesis and experience significantly improved visual acuity after the procedure.”
► A third KPro study presented at ARVO, conducted at the University of Illinois in Chicago, sounded a cautionary note. There, researchers reported that 70 KPros had been implanted over a three-year period, with clinically evident graft thinning observed in 10 of the eyes over this time frame.
Researchers stated that “the retention rate of primary KPros at our institution was 92%, but attention must be paid to these 10 patients who suffered postoperative corneal graft thinning as 60% extruded. These patients were recognized as challenging surgical candidates preoperatively as evidenced by the fact that prior PKP was only performed in 30%. Further analysis is required to identify additional associations with graft thinning as KPro extrusion usually leads to adverse visual outcomes.” OM
| In the News… |
|---|
| ■ New phaco technique trains surgeons. Cataract surgeons-in-training at Weill Cornell Medical College in New York City are being taught a novel supracapsular phaco technique designed by their instructor for beginning surgeons. Christopher E. Starr, MD, who came up with a technique that he calls “Pop and Prechop,” reported at the recent ARVO meeting that the procedure “is an effective and safe alternative to intracapsular cataract extraction.” He says the technique, which includes performing the prechop manually in the anterior chamber, combines the advantages of supracapsular surgery—and its protection of the posterior capsule—while minimizing the disadvantage of endothelial cell loss. (Dr. Starr and a colleague will describe the details of the “Pop and Prechop” procedure in an upcoming article in Ophthalmology Management.) Dr. Starr and his colleagues report that of 83 cataract surgeries performed in this manner by fellows and residents, 20% were preoperatively classified as complex. No intraoperative complications occurred in any of the cases compared to published rates of 6% to 14.7% complications in trainee surgery. All corneas were clear of edema at one month postop. ■ CATT study data compares Lucentis to Avastin. Much-awaited one-year data from the 1185-patient CATT study, released in late April, indicates that Lucentis and Avastin are about equally effective in improving vision in patients with wet AMD. However, Lucentis demonstrated a slightly greater ability to decrease central retinal thickness. One issue that remains unresolved and that will require further study is possible systemic side effects. Patients given Avastin had a 24% overall incidence of adverse events, while Lucentis patients had a 19% incidence. But the most serious adverse events, such as stroke, were about equal for both drugs. Genentech, the developer of both drugs, said the CATT study added to “an emerging body” of safety concerns regarding Avastin use in the eye. The AAO said both drugs should be available to treat wet AMD. ■ Generic Combigan gets tentative approval. Hi-Tech Pharmacal said the FDA granted tentative approval for the company's Abbreviated New Drug Application for brimonidine tartrate with timolol maleate ophthalmic solution, the generic for Allergan's Combigan glaucoma medication, which had sales of $108 million in 2010. Hi-Tech plans to launch the product after the company receives final approval from the FDA. ■ Novartis completes Alcon takeover. The complicated, several-stage $51 billion purchase of Alcon by Novartis was completed in April when shareholders of both companies approved the deal. The final stage involved a sweetened payment of approximately $168 per share in cash and Novartis stock to Alcon shareholders, who had rejected a previous lower offer. ■ IFIS: prevalence and prevention. Researchers at Jules Stein Medical Center and the Greater Los Angeles VA Medical Center, presenting at ARVO, found a strong correlation between male patients over 50 who had a history of taking alpha-1 adrenergic receptor antagonists (a1ARA) to facilitate urine flow and the incidence of intraoperative floppy iris syndrome (IFIS) during cataract surgery. Of 639 consecutive eyes studied, 26.3% had exposure to a1ARA. When the eyes exposed to a1ARA underwent phaco, 22.6% of them exhibited symptoms of IFIS. Only 1.7% of the eyes that were not exposed to a1ARA exhibited IFIS symptoms during surgery. Careful preoperative screening enabled surgeons to anticipate IFIS and take steps to deal with it. There were no significant differences between the two groups of patients in either intraoperative complications or visual outcomes. ■ Merck to acquire Inspire. As part of its increasing focus on ophthalmic drugs, Merck has announced it has a definitive agreement to purchase Inspire Pharmaceuticals for $430 million. Inspire is best known for its AzaSite treatment for bacterial conjunctivitis. ■ Generic version of Xalatan; Vigamox patent challenged. Mylan Inc. said a subsidiary, Mylan Pharmaceuticals, has received final approval from the FDA for its Abbreviated New Drug Application for Latanoprost Ophthalmic Solution, 0.005%, the generic version of Pfizer's market-leading glaucoma medication Xalatan. Pfizer's patent protection on Xalatan expired in March. Mylan President Heather Bresch said: “We are very pleased to introduce this product to the market as it represents Mylan's first ophthalmic solution.” In other news of generics, Watson Pharmaceuticals is seeking federal approval to make a generic version of Alcon's anti-infective Vigamox. Alcon has filed a patent lawsuit against Watson to prevent Watson from making and selling the product before its US patents expire on Sept. 1, 2013. ■ Ultra-thin corneal lamellar grafts. Corneal surgeons can achieve visual outcomes superior to conventional DSAEK and equivalent to DMAEK, without the surgical complications of the latter procedure, using a new microkeratome system from Moria that creates 100 µm grafts, the company says. The system includes seven single-use microkeratome heads ranging from 50 to 300 microns, plus surgical accessories and the Moria CB Microkeratome with control unit. The heads can be used in various combinations in a two-pass technique that initiates two cuts in opposite quadrants of the cornea, which will result in grafts that are thinner and more planar than conventional grafts. Studies by Italy's Massimo Busin validate the improved outcomes, Moria says. ■ Better IOP accuracy. Corneal-compensated IOP measurement, or IOPcc, accounts for corneal biomechanics rather than just correcting for central corneal thickness, and is said to be less prone to error than conventional tonometry. The IOPcc technology used in Reichert's Ocular Response Analyzer and 7CR Auto Tonometer has just been patented by the company. Over 1000 Reichert IOPcc devices are installed worldwide, the company says. ■ Stroke risk with Avastin. A paper presented at the recent ARVO meeting and encompassing almost 79,000 Medicare beneficiaries indicates that wet AMD patients receiving multiple Avastin intravitreal injections are at greater risk for death and hemorrhagic cerebrovascular accident (CVA) than patients receiving multiple injections of Lucentis. The risk for mortality was found to be 11% greater with Avastin and the risk for CVA was found to be 57% greater. The study was conducted by researchers at Johns Hopkins University, the Doheny Eye Institute, and the University of Wisconsin-Madison, with support from Genentech. ■ Glaukos on “Next Big Thing” list. Glaukos has been named to The Wall Street Journal's “The Next Big Thing” list, which seeks to identify and rank venture-backed companies across all industries that have the capital, executive experience and investor know-how to succeed. Glaukos developed the iStent for safer, blebless glaucoma surgery. The iStent has been approved in Canada and Europe and is awaiting FDA approval in the US. |
![]({"src":"/media/xihfyo05/52011.jpg","focalPoint":null,"crops":[{"alias":"thumbnail","width":1110,"height":700,"coordinates":null}]})