All spectral-domain optical coherence tomographers, despite different resolution and acquisition rates, have the same ability to detect glaucoma, says a team of U.S. and Brazilian researchers. Their study compared the diagnostic accuracies of retinal nerve fiber layer thickness measurements obtained with the Spectralis (Heidelberg Engineering), Cirrus (Carl Zeiss Meditec), and RTVue (Optovue). Researchers evaluated a total of 233 eyes (107 healthy, 126 glaucomatous) of 149 participants from the longitudinal Diagnostic Innovations in Glaucoma Study (DIGS) and from the African Descent and Glaucoma Evaluation Study (ADAGES). All participants underwent RNFLthickness imaging with the Spectralis, Cirrus, and RTVue devices in the same visit. Receiver operating characteristic (ROC) curves adjusted for age and race were obtained for quadrants (superior, nasal, inferior, temporal) and global RNFLthickness for all instruments. Areas under ROC (AUC) and sensitivities at fixed specificities (80 percent and 95 percent) were calculated and compared as the main outcome measure.

The researchers found that the RNFLthickness parameter with the largest AUCs was the superior quadrant for the Spectralis (0.88) and the global RNFL thickness for the Cirrus (0.88) and the RTVue (0.87). The pairwise comparison among the ROC curves showed no statistical difference for all parameters except for the nasal quadrant, which had significantly larger AUC in the Spectralis and RTVue compared with the Cirrus (p<0.03 for both comparisons). There were no significant differences in sensitivities among the best parameters from each instrument (p>0.05). The superior quadrant thickness measured with the Spectralis had sensitivity of 81.9 percent at a fixed specificity of 80 percent and 70 percent at a fixed specificity of 95 percent. The global thickness measured by the Cirrus had a sensitivity of 80.3 percent at a fixed specificity of 80 percent and 65.6 percent at a fixed specifi city of 95 percent. For the RTVue, the global thickness had a sensitivity of 77.9 percent at a fixed specificity of 80 percent, and 62.1 percent at a fixed specificity of 95 percent.

Ophthalmology 2011;118:1334-9.
Leite MT, Rao HL, Zangwill LM, et al.

Simultaneous and Sequential Cataract Surgeries Fairly Equal
A two-part study conducted at the Helsinki University Eye Hospital in Finland assessed clinical and economic outcomes for simultaneous and sequential bilateral cataract surgery.

The first part of the study, designed as a clinical trial, showed that refractive outcomes, rates of complications, and patient-rated satisfaction were similar whether bilateral cataract surgery was performed simultaneously or sequentially. Consecutive patients scheduled for bilateral cataract surgery were enrolled based on appropriate inclusion criteria and randomized to be operated on in one session (study group) or sequentially (control group) four to six weeks apart.

Four hundred ninety-one (94.4 percent) of the 520 patients completed the study. Of the eyes, 493 (247 patients) had bilateral surgery in one session and 506 (257 patients) in separate sessions. In the study group, 240 patients (96 percent) were treated per protocol. In the control group, 250 patients (97.3 percent) were treated per protocol. The refraction was within ±0.50 D of the target in 67.2 percent of eyes in the study group and 69.2 percent of eyes in the control group, and within ±1 D in 91.0 percent and 90.3 percent, respectively (p=0.92). The only complication that affected postoperative visual acuity was chronic cystoid macular edema, which occurred in one eye in the study group (0.2 percent) and in two eyes (0.4 percent) of one patient in the control group (p=0.57). Ninety-five percent of patients in both groups reported being very satisfied with surgery.

Results from the second part of the study suggested that sequential and simultaneous bilateral cataract surgery provided comparable clinical outcomes with substantial savings in health-care and non-health-carerelated costs. Researchers estimated the effects of the procedures from data in a study in which patients were randomized to have bilateral cataract surgery on the same day (study group) or sequentially (control group).

The main clinical outcomes were corrected distance visual acuity, refraction, complications, Visual Function Index-7 (VF-7) scores and patient- rated satisfaction with vision. Health-care costs of surgeries and preoperative and postoperative visits were estimated, including the cost of staff, equipment, material, floor space, overhead and complications.The data were obtained from staff measurements, questionnaires, internal hospital records and accountancy. Non-health-care costs of travel, home care and time were estimated based on questionnaires from a random subset of patients.

The main economic outcome measures were cost per VF-7 score unit change and cost per patient in simultaneous versus sequential surgery. The study comprised 520 patients (241 patients included non-healthcare and time cost analyses). Surgical outcomes and patient satisfaction were similar in both groups. Simultaneous cataract surgery saved 449 per patient in health-care costs and 739 when travel and paid homecare costs were included. The savings added up to 849 per patient when the cost of lost working time was included.

J Cataract Refract Surg 2011;37:992-1002.
Sarikkola AU, Uusitalo R, Hellstedt T, et al.

J Cataract Refract Surg 2011;37:1003-8.
Leivo T, Sarikkola AU, Uusitalo RJ, et al.

Higher IOP Common After Intravitreal Injection
Elevated intraocular pressure, sustained or unsustained, after intravitreal injection is not uncommon, suggests new research from the University of California Los Angeles.

In an attempt to investigate elevated intraocular pressures (defined as a measurement >25 mmHg at a follow-up visit) after an intravitreal injection of anti-vascular endothelial growth factor agents for age-related macular degeneration, the researchers did a retrospective review of medical records for 27 patients (155 eyes) that received an intravitreal injection of anti-vascular endothelial growth factor agents (bevacizumab, ranibizumab or pegaptanib) ranging from one to 39 injections for more than a period of 30 to 1,759 days.

Results showed that, among this population, 12 patients (14 eyes; 9.4 percent) developed elevated IOP 25 mmHg. Of these, seven patients (5. 5 percent) developed sustained elevated IOP (IOP >25 mmHg on two separate visits requiring glaucoma medication or surgery), of which eight eyes required topical medications and one eye underwent glaucoma surgery.

Mean IOP of injected eyes receiving intravitreal injection was 15.2 ±2.4 mmHg, and the mean IOP was 14. 9 ±2.6 mmHg for noninjected eyes. Among eyes that had elevated IOPs, there was no association with injection frequency, number of injections or anti-vascular endothelial growth factor agent used.

Retina 2011;31:1028-35.
Choi D, Ortube MC, McCannel C, et al.

Low-dose Triamcinolone Safe In Treating Vitreoretinopathy

Chinese researchers find low-dose (2 mg) triamcinolone acetonide intravitreal injection as an adjunct to vitrectomy and silicone oil tamponade in treating proliferative vitreoretinopathy (grade C or D) to be effective and safe. Researchers from the Chinese University of Hong Kong reviewed a retrospective interventional case series to evaluate the midterm anatomical and functional outcomes of intravitreal injection of low-dose triamcinolone acetonide in silicone oil-filled eyes as an adjunctive treatment.

Patients with proliferative vitreoretinopathy grade C or D received pars plana vitrectomy combined with silicone oil tamponade and intravitreal injection of 2 mg of triamcinolone acetonide in the first stage and silicone oil removal in the second stage. Primary outcome measures were retinal reattachment rate and best-corrected visual acuity.

Thirty-seven eyes from 37 patients were included in this study. The mean follow-up duration was 22. 9 ±9.6 months. Retina was reattached in 36 (97.3 percent) eyes at the last visit. The mean best-corrected visual acuity was 1.76 ±0.56 logMAR at baseline, which improved to 0.87 ±0.60 logMAR at the last visit (p<0.001). Best-corrected visual acuity increased in 31 (83.8 percent) eyes, remained unchanged in five(13. 5 percent) eyes, and decreased in one (2.7 percent) eye at last visit compared with baseline.

Retina 2011;31:1137-42.
Chen W, Chen H, Hou P, et al.

Post-PK Suture Infections Less Common Than Reported?
The rate of suture-related infections after penetrating keratoplasty may be lower than previously reported, suggests new research from the Cole Eye Institute in Cleveland. Researchers reporting on the incidence, occurrence rate and characteristics of suture-related infections after PK evaluated patients who underwent PK at the institute between January 2002 and July 2006. Those patients were cross-referenced with patients diagnosed with corneal infections between January 2002 and July 2007. All patient charts were reviewed retrospectively for occurrence of suturerelated infections, duration of follow-up and clinical characteristics.

Of the 487 Pks performed in 412 patients, 22 eyes of 22 patients developed postoperative corneal infections. Of these, five eyes were identified as having suture-related graft infections, yielding an occurrence rate of 1 percent. The average followup was 3.46 years per PK, yielding an incidence of 2.96 infections per 1,000 PK-years. The mean interval from surgery to infection was eight months (range: three to 23 months).

All culprit sutures were in the interpalpebral zone. No patients were using topical antibiotics at the time of infection, and all patients were using topical corticosteroid drops. Cultured organisms included Staphylococcus aureus (three cases), coagulase-negative Staphylococcus (one case) and S. viridans (one case).

In two patients with isolated corneal involvement, topical moxifloxacin was initiated, and the patients responded favorably. In three patients with corneal infection and an associated hypopyon or endophthalmitis, vitreous biopsy, intravitreal injections of antibiotics and fortified topical antibiotics were used. One patient required a repeat PK as a result of the infection. Two eyes eventually became phthisical.

Cornea 2011;30:624-8.

Hood CT, Lee BJ, Jeng BH.

Ortho-K Lenses May Affect Epithelium After Short Wear
New research shows that overnight orthokeratology lenses for myopia induce significant structural and optical changes, particularly in the central epithelium, after 15 days or one month of wear.

In a prospective, single-center, longitudinal trial to examine the morphological and biometric corneal changes produced by ortho-K lenses, researchers at University School of Optics in Madrid reviewed 27 right eyes of 27 subjects (group 1) with low to moderate myopia who wore ortho-K lenses for one month. Ten right eyes of 10 subjects (group 2) with emmetropia to low myopia who did not wear any type of contact lens served as controls. Corneal morphometric measurements were obtained in vivo using a confocal microscope to examine the central and midperipheral cornea. Thickness measurements in the peripheral cornea were obtained by optical coherence tomography. Changes in visual acuity, refractive error and corneal topography were also analyzed.

No significant changes in either endothelial cell or stromal cell density were observed after one month of ortho-K. Basal epithelial cells were, however, significantly reduced (p<0.01), and epithelial wing and superficial cells showed enhanced visibility (p<0.05). Superficial cells increased in height and width, the width increase after one month being significant (p<0.01). Epithelial thickness was significantly reduced in the central cornea and 2 mm around the center. Corneal pachymetry increased significantly in the band from 5 to 10 mm from the corneal apex (p<0.01).

The researchers concluded that the central corneal epithelium responds to ortho-K wear by undergoing significant epithelial cell shape and size alterations with no effects, however, on the cells of the corneal endothelium or the corneal stroma. Peripheral corneal thickness increased with respect to baseline values.

These findings suggest that the corneal epithelium is the principal structure affected by the mechanical forces exerted by the ortho-K lenses, the group concludes.

Cornea 2011;30:646-54.
Nieto-Bona A, González-Mesa A, Nieto-Bona MP, et al.