Volume 9, Number 33
Monday, August 24, 2009



In this issue: (click heading to view article)
Healing Response at the Flap Interface in Patients with LASIK Ectasia Requiring Penetrating Keratoplasty
Impact of Phacoemulsification Cataract Surgery on the Progression and Development of Diabetic Retinopathy
Changes in Optic Nerve Cup–to–Disk Ratio in Patients Receiving Multiple Intravitreal Injections of Anti-VEGF
Effect of Topical Anesthetic Cataract Surgery on Ocular Alignment
Briefly





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Healing Response at the Flap Interface in Patients with LASIK Ectasia Requiring Penetrating Keratoplasty

To evaluate the healing response at the flap interface in corneas with LASIK ectasia that required penetrating keratoplasty (PK), researchers collected the corneas of five patients who developed corneal ectasia following LASIK (range: 2.5 to 5 years postoperative) after corneal transplant surgery. They also bisected the corneas and processed them for conventional histologic analysis and immunofluorescence.

Light microscopy showed a hypocellular fibrotic scar at the wound margin compared with the adjacent corneal stroma in all eyes, reported the researchers. They noted that all corneas had positive staining for alpha-smooth muscle actin (SMA), a myofibroblast marker and in one eye, alpha–SMA cells were located in the fibrotic scar region in the area of the semicircular ring of haze along the margin of the LASIK flap corresponding to an area of epithelial ingrowth. In all other eyes, alpha–SMA positive cells were fewer and mainly located in the superficial stroma under the epithelial wound margin surface.

The study researchers observed that type III collagen was minimal or absent in the central zone and wound margin of all corneas except for the cornea with epithelial ingrowth present in the hypercellular fibrotic scar region. Additionally, chondroitin sulfate was stronger in the periphery of the flap wound coinciding with a higher presence of alpha–SMA–positive cells in that region and the researchers saw positive staining for matrix metalloproteinase 9 (MMP–9) in the paracentral wound margin scar.

They noted a wound-healing process characterized by absence of significant fibrosis and myofibroblasts at the wound edge in the flap interface in all keratectatic eyes. However, changes in the composition of collagen and the presence of MMP–9 at the wound edge several years after LASIK indicates active wound remodeling that may explain the ongoing loss of tissue and tendency of the cornea to bulge, the researchers concluded.

SOURCE: Esquenazi S, Esquenazi I, Grunstein L, et al. Immunohistological evaluation of the healing response at the flap interface in patients with LASIK ectasia requiring penetrating keratoplasty. J Refract Surg 2009;25:739–746.






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Impact of Phacoemulsification Cataract Surgery on the Progression and Development of Diabetic Retinopathy

The authors of this Australian, clinic-based, cohort study assessed whether phacoemulsification cataract surgery exacerbates the development and progression of diabetic retinopathy (DR) in a cataract surgical cohort. Participants were patients aged 65+ years undergoing cataract surgery at an eye clinic in Sydney, Australia, between 2004 and 2006.

The study authors performed digital retinal photography after pupil dilation preoperatively and at 1–, 6– and 12–month postoperative visits and assessed DR using the modified Early Treatment Diabetic Retinopathy Study (ETDRS) classification. They then compared preoperative and 1-month postoperative (baseline) photographs side-by-side with 12–month postoperative photographs and calculated odds ratios (ORs) and 95% confidence intervals (CIs) for DR progression in operated (pseudophakic) compared with nonoperated (phakic) eyes, adjusted for age, sex, diabetes duration and preoperative glycosylated hemoglobin level.

For main outcome measures, incident DR was defined in eyes without DR at baseline in which DR was detected at 12–month postoperative visits and DR progression was defined as an increase of 1 or more ETDRS steps during the same period, including incident cases. Of 1994 surgical patients recruited, 190 (9.53%) with diabetes and complete data and thus were included. There were 56 patients with unilateral surgery performed before baseline (mean postoperative duration 3.3 ± 3.3 years). The authors reported that the prevalence of DR at baseline was higher in these 56 pseudophakic eyes than in 324 phakic eyes (71.4% vs. 48.2%, respectively, adjusted OR 2.16; 95% CI, 1.16–4.03). Also, that of the 190 patients, 169 were followed for 12+ months postoperatively; 278 eyes were pseudophakic and 60 eyes remained phakic at 12 months. During the 12–month postoperative period, incident DR developed in 28.2% of pseudophakic eyes and 13.8% of phakic eyes (adjusted OR 2.65; 95% CI, 1.06–6.61). Moreover, in a paired–eye comparison of 45 patients who remained unilaterally pseudophakic at 12 months and were at risk of DR progression, 35.6% of pseudophakic eyes exhibited DR progression compared with 20.0% of the fellow phakic eyes (adjusted OR 2.21%; 95% CI, 0.85–5.71).

Per the authors' conclusion, diabetic patients undergoing phacoemulsification cataract surgery appear to have a doubling of DR progression rates 12 months after surgery. This outcome, however, represents less progression than was previously documented with intracapsular and extracapsular cataract surgical techniques.


SOURCE: Hong T, Mitchell P, de Loryn T, et al. Development and progression of diabetic retinopathy 12 months after phacoemulsification cataract surgery. Ophthalmol 2009;116(8):1510–1514.






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Changes in Optic Nerve Cup–to–Disk Ratio in Patients Receiving Multiple Intravitreal Injections of Anti-VEGF

This study was conducted to assess whether the transient IOP rise, frequent IOP fluctuations or antivascular endothelial growth factor (VEGF) effects of repeated intravitreal injection of anti–VEGF agents can lead to changes in the optic nerve vertical cup–to–disk ratio (C/D).

Excluding patients with a known history of glaucoma and those receiving triamcinolone acetonide, fundus photographs were cropped to optic disk images only, which were then randomized and independently graded by two glaucoma specialists. The fellow eye was used as a control in patients who received treatments in only one eye.

A total of 23 eyes of 21 patients met inclusion criteria. It was reported that the mean change in C/D was –0.012 (95% confidence interval [CI], –0.053 to 0.029) for the treated groups and -0.006 (95% CI, –0.106 to 0.095) for the control group, with no statistically significant difference (p=0.90). Additionally, the mean change in C/D for eyes receiving ≤5 injections (n=9) was 0.003 (95% CI, –0.089 to 0.095) in the treated group and 0.054 (95% CI, –0.033 to 0.142) in the control group, with no statistically significant difference (p=0.33). In eyes receiving >5 injections (n=14), the mean change in C/D was –0.021 (95% CI, –0.095 to 0.052) in the treated group and –0.057 (95% CI, –0.231 to 0.116) in the control group, with no statistically significant difference (p=0.70).

It was concluded that there was no statistically significant change in the vertical C/D of optic nerves in patients receiving multiple intravitreal injections of anti–VEGF agents, regardless of whether they received fewer or more than five total injections. This suggests that the short–term IOP rise and frequent IOP fluctuation, as well as the anti–VEGF properties of these drugs, do not adversely change the optic nerve C/D. To confirm these conclusions, additional prospective studies are warranted.

SOURCE: Seth RK, Salim S, Shields MB, et al. Assessment of optic nerve cup–to–disk ratio changes in patients receiving multiple intravitreal injections of antivascular endothelial growth factor agents. Retina 2009;29(7):956–959.




When your PGA patients need a change




Effect of Topical Anesthetic Cataract Surgery on Ocular Alignment

Investigators in Korea prospectively evaluated 160 consecutive patients who were scheduled for cataract surgery under topical anesthesia to report the incidence of, and change in ocular misalignment following topical anesthetic cataract surgery. They gave all patients a complete ophthalmic examination, including ocular alignment evaluation, just before and 1 day, 1 week, 3 weeks and 2 months after cataract surgery.

Preoperatively, 26 patients had ocular misalignment, reported the investigators. They also noted that mean deviation in these pre-existing misalignment was 7.2 ± 6.8 prism diopters (PD) and that postoperatively, the angle of deviation improved to 5.4 ± 7.4 PD. Moreover, acquired ocular misalignment after cataract surgery occurred in 12 of 160 patients (8%) at 1 day, and 7 of 131 (5%) at 2 months. None of these 7 patients sought medical attention for the diplopia.

According to the study investigators, the overall incidence of topical anesthesia–related change in ocular alignment after uneventful cataract surgery was 5%; however, no patients had symptomatic diplopia. They determined that topical anesthetic cataract surgery could abolish the risk of postoperative diplopia and improve the heterophoric status of pre-existing misalignment.

SOURCE: Chung SA, Kim CY, Chang JH, et al. Change in ocular alignment after topical anesthetic cataract surgery. Graefes Arch Clin Exp Ophthalmol 2009;247(9):1269–1272.









  • ADVANCED VISION RESEARCH MOURNS THE LOSS OF ITS FOUNDER. Last week, doctors at Massachusetts General Hospital in Boston announced the death of Jeffrey P. Gilbard, MD, Founder, CEO and Chief Scientific Officer of Advanced Vision Research (AVR). He was 55. As a medical student in the summer of 1976, Dr. Gilbard met his first patient with dry eyes and was inspired. He began a summer research project with the goal of developing an eye drop for dry eye. In 1978, he received project grant funding from the National Eye Institute and in 1995, founded AVR to market and distribute TheraTears, a revolutionary over– the–counter eye drop he created to treat dry eye. His holistic approach to eye care included the use of nutritional supplements to improve the ocular surface and to treat and prevent retinal disease. The AVR executive team, led by Chief Operating Officer Leigh Reynolds will continue to run the company. Dr. Gilbard is survived by his wife, Liz; three children; twin brother, Dr. Steven M. Gilbard; and older brother, Dr. Robert J. Gilbard.
  • TWO NEW INSTRUMENTS FOR CRYSTALENS SURGERY AVAILABLE IN U.S. Bausch & Lomb Storz Opthalmic Instruments has released two new instruments for use during Crystalens surgery: the Brown Crystalens Haptic Placement Forceps and the Lindstrom Lens Positioner. According to the company, the Brown Crystalens Haptic Placement Forceps have a “trident”–shaped tip designed to securely grasp the lens at the incision and position it in the capsule. The Lindstrom Lens Positioner is a versatile instrument featuring a semi-sharp angled tip that allows the surgeon to position an IOL by engaging optic material and is specially designed for the Crystalens and Akreos lenses to effectively facilitate movement of the lens in the capsule without marking it. For additional information, click here.
  • ENROLLMENT FOR iSONEP PHASE 1 STUDY COMPLETE. Lpath, Inc. has completed the enrollment and dosing of 15 wet AMD patients in a multi-center, open label, single–arm Phase 1 study of iSONEP administered as a single intravitreal injection to the study eye. iSONEP is the ocular formulation of humanized Sphingomab and is Lpath's second product candidate. According to a press release, iSONEP exhibits anti–fibrotic and anti–inflammatory properties that might provide comparative advantages in the AMD realm and is also suggestive of efficacy against glaucoma when surgery is required. The company reported that the drug was well tolerated in all 15 patients, and there were no drug–related serious adverse events reported at any of the five dose levels (0.2 mg/eye to 1.8 mg/eye). Furthermore, several patients showed a reduction in retinal thickness and regression of lesion size, the two primary efficacy–related endpoints in a single–dose Phase 1 trial. Lpath is expected to release a complete analysis of efficacy when all the data are available later this quarter.
  • OPHTHALMOLOGISTS TO BE HONORED FOR CONTRIBUTIONS AND DEDICATION. Nine ophthalmologists will be honored by the International Society of Refractive Surgery of the American Academy of Ophthlamology (ISRS/AAO) at this year's ISRS/AAO 2009 Gala Dinner on October 23 in San Francisco during the AAO's Joint Meeting. Alaa M. El Danasoury, MD; Canan Asil Utine, MD, MsC; Dimitri T. Azar, MD; Donald Tan, MD, FRCS, FRCOphth; George O. Waring III, FRCS; Guy M. Kezirian, MD; John Marshall, PhD; Jorge L. Alio, MD; and Steven E. Wilson, MD, are being recognized for their special contributions to society, as well as their dedication to ophthalmology. Visit www.isrs.org for descriptions of the awards and recipient bios as well as additional information.