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Cataract surgery does not increase risk of AMD progression
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SAN FRANCISCO – Cataract surgery does not appear to impact progression of age-related macular degeneration, and observations of more advanced disease after cataract removal may result from an improved diagnostic ability to identify underlying pathology after removal of an opacified lens, a lecturer said here at the American Academy of Ophthalmology meeting.
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At the Retina Subspecialty Day, Susan B. Bressler, MD, said several researchers have proposed different theoretical mechanisms by which cataract removal may increase the risk of AMD progression, including increased delivery of potentially toxic blue light, surgically induced inflammation and the potential for shared risk factors for both pathologic states.
Some large-scale population studies have suggested an association between the two conditions, but Dr. Bressler noted, “I cannot stress this enough: Association does not imply causation.”
In a small study performed at the Wilmer Eye Clinic, Dr. Bressler and colleagues noted a low incidence of either geographic atrophy or choroidal neovascularization developing between 1 week and 1 year after cataract surgery in 71 prospectively followed patients.
Likewise, Dr. Bressler said, analysis of data from the AREDS study revealed no increased risk on Cox regression analysis, a potentially small increased risk in comparing case (cataract removal) and age-matched controls, but no increased risk on logistic regression.
“There is no clear evidence that AMD eyes are at a clinically important greater risk of progression to advanced AMD following cataract surgery,” she said.
No causal link found between LASIK, RD
Retinal detachment may occur rarely after LASIK, but there does not appear to be a cause-effect relationship, a speaker said.
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A retrospective review of 11,594 patients with baseline myopia greater than or equal to 10 D and a minimum of 10 years of follow-up showed a cumulative incidence of 0.19% (22 eyes of 19 patients), J. Fernando Arevalo, MD, FACS, said during Refractive Surgery Subspecialty Day. The number was lower than the incidence of rhegmatogenous retinal detachment (0.7% to 6%) thought to occur in the general population of patients with significant myopia, Dr. Arevalo said.
While 1.5% of eyes required preoperative therapy for predisposing retinal lesions, no patients who developed retinal detachment had been treated prophylactically, Dr. Arevalo said.
In the study, rhegmatogenous retinal detachment occurred between 1 month and 13 years (mean 31.6 ± 39.3 months) and developed in patients with myopia ranging from –1.5 D to –9.75 D (mean –4.81 ± 2.2 D).
Imaging technique allows visualization of the choroid
Even though the choroid carries most of the blood flow in the eye and is at the center of several retinal pathologies, current imaging modalities provide poor visibility of the area.
However, pushing a spectral domain optical coherence tomography device closer to the eye and obtaining an inverted image averaged from 100 scans allows for deeper penetration and greater resolution of the choroid, Richard F. Spaide, MD, said during Retina Subspecialty Day.
The technique has already yielded new understanding of the relationship between choroidal structure and visual function. According to Dr. Spaide, testing of the technique in 54 eyes without known pathology revealed what he called “age-related choroidal atrophy” in a subset of elderly non-myopic patients with decreased vision and difficulty reading and seeing in dim light.
These patients were a mean 80.6 years old and had an average choroidal thickness of 69.8 µm, Dr. Spaide said. One-third of patients had glaucoma.
The technique has also helped elucidate features of central serous chorioretinopathy and pathologic myopia, he said.
Survey reflects laser correction market decline
The annual survey of ISRS/AAO members showed overall laser vision correction volume was down 15% among its members, according to a speaker.
The annual ISRS/AAO refractive surgery survey was conducted online for the first time in 2009 and received a response rate of 19.4%, Richard J. Duffey, MD, said at the Refractive Surgery Subspecialty Day.
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The survey showed that about 25% of refractive surgeons have had some form of modern refractive correction, which is still three or four times greater than that of the general population, and rates of family members getting correction were even higher, he said.
Other findings were that the Visx excimer laser still dominates the laser market with a 58% share, but the WaveLight laser system was on the rise at 28% of the market, according to Dr. Duffey.
Among premium IOLs, the ReSTOR was implanted 9% of the time, and the Crystalens and Tecnis were implanted 6% and 4% of the time, respectively.
Novel anti-VEGF agent offers potential for longer duration of effect with fewer doses
Data from the extension study of a novel anti-VEGF agent suggest clinically significant improvements in vision with low dosing burden and a favorable safety profile, a speaker said.
In the CLEAR-IT 2 extension study, 117 patients were followed with as-needed therapy with VEGF Trap (aflibercept, Regeneron), which binds the two key VEGF receptors in the eye and may offer improved affinity, duration and penetration compared with current agents, David S. Boyer, MD, said.
In the study, patients received three monthly loading doses, followed by 21 months of as-needed therapy. Overall, 9% of patients required no additional therapy in the as-needed therapy phase and 50% required fewer than four doses. According to Dr. Boyer, the mean number of doses delivered was 4.6 per patient over the 2 years of study.
Patients gained 7.3 letters of visual acuity during the initial 3-month loading phase and increased to 8.4 letters through 12 months. Patients gained 7.1 letters at 18 months and 6.1 letters at 24 months, Dr. Boyer said.
PresbyLASIK procedure shows safe, effective long-term results
The creation of a multifocal cornea with an excimer laser for the correction of presbyopia has been shown to be safe and effective in the long term, according to a speaker.
Gustavo Tamayo, MD, presented results at the International Society of Refractive Surgery Refractive 2009 meeting from a study of the presbyLASIK procedure on 97 eyes followed up for a mean of 39.9 months.
According to Dr. Tamayo, 96% of his patients were spectacle-free following surgery, and 100% of patients gained one line of near uncorrected visual acuity. In addition, there was no loss of best corrected visual acuity following surgery.
“While the surgery produces some of the same visual disturbances as multifocal IOL surgery, this surgery has the advantage of being noninvasive and completely reversible,” Dr. Tamayo said.
John A. Hovanesian, MD, FACS, a Primary Care Optometry News Editorial Board member, said that the take-home message from this presentation is that “multifocal ablations on the cornea are not only possible but also achieve acceptable near vision for many patients.” More importantly, he said, they are reversible.
“This is obviously important because of the concern among surgeons that multifocal optics are not accepted well by every patient and therefore the idea that it is reversible is desirable if we are doing a permanent corneal ablation,” he said.
Annual optic disc imaging provides knowledge of glaucoma change
Imaging of the optic disc at different stages of glaucoma progression is an effective means of following optic disc change in both suspect and confirmed cases, a glaucoma expert said.
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Richard K. Parrish II, MD, said that careful review and repetition of optic disc imaging after initial baseline assessment helps in determining glaucomatous change and progression. He said there are several ways of recording optic disc appearance, including freehand drawings, sequential and simultaneous stereoscopic photographs.
He outlined the method of optic disc documentation used at Bascom Palmer Eye Institute during a session at Glaucoma Subspecialty Day.
“[We] document baseline simultaneous stereoscopic photographs in glaucoma patients, those who are early and moderate in the course of their disease, ocular hypertensives, and review the photographs annually, repeating them if there is a question of change,” he said.
DSAEK causes more immediate cell loss but less over time than PK
Endothelial cell loss may be more dramatic after Descemet’s stripping automated endothelial keratoplasty compared with penetrating keratoplasty immediately after surgery, but long-term results favor the newer technique, a speaker said.
Published studies to date comparing the two procedures have documented a better prognosis for patients undergoing DSAEK despite a greater proportion of patients receiving a transplant for Fuchs’ dystrophy, Jonathan H. Lass, MD, said during Refractive Subspecialty Day.
These studies have noted a higher occurrence of perioperative trauma and a 15% higher repositioning rate with DSAEK compared with PK, Dr. Lass said. Published comparative studies have noted a two times higher rate of endothelial cell loss in the first 6 months after DSAEK compared with PK (around 30% to 35%), but a stable rate thereafter to a maximum of 4 years in clinical follow-up data, Dr. Lass said.
By contrast, PK tends to have a much slower but more consistent rate of endothelial cell loss in the postoperative period, which eventually results in greater overall cell loss after about 3 years, Dr. Lass said.