Pneumatic retinopexy for primary repair of rhegmatogenous retinal detachments.

PURPOSE: To evaluate anatomical and functional outcomes of pneumatic retinopexy (PR) for primary repair of rhegmatogenous retinal detachments and to determine demographic and ocular risk factors for failure of the procedure. DESIGN: Retrospective interventional case series. METHODS: A chart review on 97 eyes of 97 consecutive patients who had undergone PR as the initial procedure for unilateral recent primary retinal detachments with causative break(s) in the superior two-third of the retina. After injection of 0.35 mL to 0.60 mL of sulfur hexafluoride, 6 hours face-down positioning, and the steamroller maneuver, the patient's head position was changed so that the gas could efficiently tamponade the retinal break(s). Pre- and post-gas injection laser photocoagulation of break(s) and 360° peripheral retina was applied. RESULTS: Seventy-two male and 25 female patients were included in this study. The single-operation success rate was 82.5%. The pars plana vitrectomy procedure as the second intervention was not adversely affected by the preceding PR. Presence of proliferative vitreoretinopathy (odds ratio: 58.7, 95% confidence interval: 7.8-443.5) and delay between initial symptoms and PR (odds ratio: 1.21 per each additional day, 95% confidence interval: 1.07-1.37) were the only independent predictors for the failure. CONCLUSION: With proper selection of cases, PR is a good surgical option for primary rhegmatogenous retinal detachments with acceptable success rate, minimal discomfort to the patient, and minimal surgical risks.

Deep anterior lamellar keratoplasty for keratectasia after laser in situ keratomileusis.

PURPOSE: To assess the efficacy of deep anterior lamellar keratoplasty (DALK) for treating post-LASIK keratectasia. SETTING: Poostchi Eye Research Center, Shiraz University of Medical Sciences, Shiraz, Iran. DESIGN: Retrospective interventional cases series. METHODS: The same surgeon performed all DALK procedures using the Melles manual technique. The preoperative and postoperative corrected distance visual acuity (CDVA), spherical equivalent (SE) refraction, keratometry (K) readings, and endothelial cell profiles were compared. RESULTS: The cohort comprised 20 eyes of 18 patients (72% women) with a mean age of 29 years ± 4 (SD). The mean follow-up was 31.8 ± 17.0 months (range 6 to 60 months). The mean Snellen CDVA improved significantly from 20/191 before DALK to 20/23 after DALK (P < .001). The mean of the modulus of SE refraction was 11.9 ± 6.6 diopters (D) and 11.4 ± 4.3 D, respectively (P = .446). The mean K value was 52.2 ± 7.0 D before DALK and 46.0 ± 1.9 D after DALK (P = .001); the mean apical K value, 59.5 ± 5.1 D and 49.9 ± 2.8 D, respectively (P < .001); and the mean keratometric astigmatism, 4.3 ± 2.4 D and 1.9 ± 1.2 D, respectively (P = .003). The endothelial cell profile did not change significantly, and no major complications related to DALK occurred. Twelve eyes had additional refractive procedures to correct residual ametropia. CONCLUSION: Deep anterior lamellar keratoplasty using the Melles manual technique was effective and safe in restoring CDVA in patients with post-LASIK keratectasia; however, high residual ametropia was a common finding.

Results of Ahmed glaucoma valve implantation in primary congenital glaucoma.

PURPOSE: To evaluate the outcome of Ahmed glaucoma valve (AGV) implantation in primary congenital glaucoma (PCG). METHODS: The medical records of patients with PCG refractory to trabeculotomy and medical therapy who had undergone AGV implantation with a minimum follow-up of 6 months were retrospectively reviewed. The primary outcome measure was cumulative probability of success, defined as intraocular pressure (IOP) of 6-21 mm Hg, with or without medication, and no serious complications, additional glaucoma surgery, or loss of light perception. RESULTS: A total of 33 eyes of 22 children with a mean age (and standard deviation) of 2.7 ± 3.1 years were included. The patients had a mean follow-up time of 32.6 ± 18.3 months. The mean IOP was 32.8 ± 7.3 mm Hg preoperatively and 16.8 ± 4.0 mm Hg postoperatively. The number of glaucoma medications was 2.5 ± 0.7 preoperatively and 2.2 ± 0.7 postoperatively. The cumulative probability of success (and standard error) was 97% ± 3.0% in the 1st year, 85% ± 7.0% in the 2nd year, and 56% ± 14.8% in the 5th year. When only the first operated eye per patient was included, the cumulative probability of success was 96% ± 4.4% in the 1st and the 2nd years and 72% ± 15.3% in the 5th year. Major complications comprised tube-endothelial touch (3 eyes), cataract (2 eyes), shunt extrusion (1 eye), and retinal detachment (1 eye). CONCLUSIONS: AGV implantation in patients with PCG offers moderate success in controlling the IOP with a low rate of complications. Most continued to require medications.

Diurnal variation of retinal thickness in healthy subjects.

PURPOSE: To investigate diurnal fluctuations in retinal thickness using spectral domain optical coherence tomography (SD-OCT). METHODS: Spectralis SD-OCT was used to obtain data from the right eye of 21 healthy subjects (mean age, 31.3 years) at 7 AM, 1 PM, and 7 PM. For each eye, a full peripapillary retinal nerve fiber layer circular scan and a 19-line horizontal raster scan (6- by 6-mm area) centered on the fovea were performed. RESULTS: Retinal nerve fiber layer thickness was greater at 7 AM or 1 PM than at 7 PM for nasal (79.1 µm [1 PM] vs. 77.6 [7 PM]; p = 0.024), inferior (134.1 [7 AM] vs. 131.9 [7 PM]; p = 0.009), and inferonasal (115.2 [7 AM] vs. 115.6 [1 PM] vs. 112.4 [7 PM]; p < 0.001) subfields. Macular thickness was greater at 7 AM than at 7 PM for inferior 6 mm (290.2 µm [7 AM] vs. 287.8 [7 PM]; p < 0.001) ETDRS (Early Treatment Diabetic Retinopathy Study) subfield. Macular volume was greater at 7 AM than at 7 PM for nasal 3 mm (0.541 mm vs. 0.538; p = 0.028) and inferior 6 mm (1.538 vs. 1.525; p < 0.001) ETDRS subfields. The remaining studied areas did not show any significant change throughout the day. CONCLUSIONS: The Spectralis SD-OCT retinal thickness measurements showed a small but statistically significant diurnal variation in nasal and inferior subfields toward smaller values in the evening. However, the overall change is close to the instrument's resolution and repeatability.

Comparison of Horizontal corneal diameter measurements using the Orbscan IIz and Pentacam HR systems.

PURPOSE: To compare 2 automated devices for measuring the horizontal corneal diameter [white-to-white (WTW) distance]. METHODS: In this prospective comparative case series, the WTW distance was measured by independent examiners using the Pentacam HR and the Orbscan IIz in 101 eyes of 101 healthy refractive surgery candidates. Statistical evaluation was performed using the paired t test, Pearson correlation, and the Bland-Altman method for comparison of measurement techniques. RESULTS: The mean WTW distance measurements were 11.76 ± 0.38 mm as obtained with the Pentacam HR and 11.66 ± 0.37 mm as obtained with the Orbscan IIz (P < 0.001). The measurements were highly correlated (Pearson correlation coefficient = 0.948; P < 0.001). The 95% limits of agreement for the Pentacam HR versus the Orbscan IIz were -0.14 to 0.33 mm. CONCLUSIONS: The observed differences in WTW distance readings between the Pentacam HR and the Orbscan IIz are not clinically relevant, and the 2 devices could be used interchangeably in clinical practice.

Changes in corneal endothelial cell profile measurements after deep anterior lamellar keratoplasty for keratoconus.

PURPOSE: The primary objective was to evaluate whether postoperative alterations in corneal shape (as reflected by keratometry values) affect endothelial cell profile measurements after deep anterior lamellar keratoplasty (DALK) in a group of patients with keratoconus. Secondary objective was to describe the pattern of changes in corneal endothelial cell profile measurements during the first 3 years after DALK. METHODS: In this prospective interventional case series, we enrolled patients who had significant keratoconus and were scheduled for DALK (Melles technique). Cases with concomitant intraocular surgeries, intra-/postoperative complications, and poor quality of images were excluded. RESULTS: Two hundred one eyes and 45 eyes (of the original 201) were enrolled for evaluating the primary and the secondary objectives, respectively. At 3 months post DALK, the mean endothelial cell density (ECD) had significantly increased and the mean cell area had decreased compared with preoperative measurements (2721 vs. 2823 cells/mm2, P = 0.015; and 378 vs. 362 µm2, P = 0.005, respectively). Regression analysis revealed a weak but significant nonlinear association between changes in mean keratometry and ECD changes at 3 months (R2 = 0.039, P = 0.02). Standard deviation of mean cell area had significantly decreased at 12 months after DALK compared with measurements taken at 3 months after surgery (P = 0.023) and remained stable thereafter. CONCLUSIONS: Apparent measurements of ECD may not show a decrease but instead even a slight increase in some cases after uncomplicated DALK (Melles technique) for keratoconus. This finding along with a later decrease in standard deviation of mean cell area suggests that notable postoperative changes in corneal biomechanical forces may affect endothelial cell profile measurements.

Comparison of keratometry measurements using the Pentacam HR, the Orbscan IIz, and the TMS-4 topographer.

PURPOSE: To compare and evaluate the agreement between keratometry readings using three devices: the Pentacam HR, the Orbscan IIz, and the TMS-4 topographer. METHODS: In this prospective comparative study, 115 eyes from 115 healthy refractive surgery candidates were sequentially examined using three devices. Fourier analysis was used to evaluate corneal astigmatism in these subjects. The outcome measures comprised steep and flat keratometry readings, corneal astigmatism, the mean keratometry reading, and the J0 and J45 components. Repeated-measures analysis of variance (RM-anova) and Bland-Altman plots with 95% limits of agreement were used to evaluate the difference between measurements. RESULTS: The mean keratometry readings were 43.89 ± 1.51, 43.52 ± 1.48, and 43.79 ± 1.50 D using the TMS-4 topographer, the Orbscan IIz, and the Pentacam HR, respectively (p < 0.001; RM-anova). The mean keratometric astigmatism was 1.27 ± 0.87, 1.20 ± 0.86, and 1.21 ± 0.82 D using the TMS-4 topographer, the Orbscan IIz, and the Pentacam HR, respectively (p = 0.007; RM-anova). The J0 measurements were higher using the TMS-4 topographer compared with the Orbscan IIz (p = 0.021; Bonferroni test). The mean, steep, and flat keratometry data were in better agreement using the TMS-4 topographer and the Pentacam HR. In general, the Orbscan IIz device measured lower values than either the TMS-4 topographer or the Pentacam HR. However, the corneal astigmatism measurements and the J0 component showed the best agreement using the TMS-4 topographer and the Orbscan IIz. CONCLUSIONS: The TMS-4 topographer and the Pentacam HR produced similar readings and can be used interchangeably to measure simulated keratometry values in young, healthy eyes. To measure corneal astigmatism, the TMS-4 topographer and the Orbscan IIz produced values that were similar and could be used interchangeably.

Anti-VEGF therapy with bevacizumab for anterior segment eye disease.

PURPOSE: To review the current literature concerning the use of bevacizumab in treating neovascular disorders affecting the anterior segment ocular structures. METHODS: The authors reviewed the literature on anti-vascular endothelial growth factor (VEGF) therapy with bevacizumab for various anterior segment neovascular disorders that was indexed in MEDLINE (up to January 2011). RESULTS: Response to bevacizumab anti-VEGF therapy is variable, based on the amount of scarring, the chronicity and extent of corneal neovascularization, the disease process, and the medication formulation and its route of administration. Anti-VEGF agents are especially effective when administered early, before anatomical changes, such as corneal neovascularization and/or angle closure, are established. Neovascularization can recur if the ischemic or inflammatory process is not reversed, so eyes with long-standing diseases, such as autoimmune disorders that involve ongoing inflammation and VEGF production, seem to be less responsive to bevacizumab anti-VEGF therapy. For established neovascularization, combining anti-VEGF agents with the removal of established vessels may be more effective than anti-VEGF therapy alone. Subconjunctival bevacizumab may be more appropriate for focal, deep, and peripheral neovascularization, whereas diffuse superficial neovascularization with central corneal involvement may be best treated via topical application. CONCLUSIONS: Besides the widely accepted use of bevacizumab in cancer therapy and chorioretinal neovascularization, the initial, striking, short-term response and patients' high tolerance of local bevacizumab therapy offer encouraging results for the potential role of anti-VEGF agents in treating anterior segment neovascular disorders. Controlled prospective trials are needed to establish the long-term safety, efficacy, and dosing guidelines for the use of anti-VEGF agents in anterior segment neovascularization.

Comparison of the ultrasonographic method with 2 partial coherence interferometry methods for intraocular lens power calculation.

BACKGROUND: The accuracy of biometric measurements, particularly axial length, is critical for precise intraocular lens (IOL) power calculation and predictable refractive outcomes after cataract surgery. Partial coherence interferometry-based systems represent progress toward measurements that are more precise and reliable. The purpose of this study was to evaluate a new noncontact optical biometer (Lenstar; Haag-Streit AG, Koeniz, Switzerland) using optical low-coherence reflectometry and to compare the biometric measurements (including axial length, keratometry, anterior chamber depth, and IOL power) with those obtained from current clinical instrumentation. METHODS: Biometric measurements were obtained with Lenstar, IOL Master V.5 (Carl Zeiss Meditec AG, Jena, Germany), and A-scan applanation ultrasound scan combined with a Javal-type keratometer in 234 eyes of 234 subjects scheduled for cataract surgery. IOL power was calculated using Sanders, Retzlaff, Kraff II, Hoffer Q, and Holladay 1 formulas. RESULTS: The axial length readings were similar (P = 0.997). The anterior chamber depth measurements obtained by IOL Master were slightly smaller than those obtained with other devices (P = 0.092). The means of the average keratometry readings were 0.65 and 0.61 diopters lower when measured with Lenstar as compared with IOL Master and the Javal-type keratometer, respectively (P = 0.002). All of the measurements were tightly correlated (P < 0.001). For anterior chamber depth measurements, however, the correlation was slightly weaker. Using the above-mentioned formulas, the mean IOL power measurements were similar. These measurements were tightly correlated (P < 0.001). The level of agreement was acceptable and comparable between devices. CONCLUSIONS: The findings from this study show the validity and clinical utility of Lenstar compared with instrumentation currently used in clinical practice for assessing ocular biometry and IOL power calculation in cataractous eyes.

The role of intravitreal bevacizumab in experimental posterior penetrating eye injury.

PURPOSE: The purpose of this study was to investigate the effect of intravitreal bevacizumab on an experimental rabbit model of penetrating posterior ocular injury. METHODS: The right eyes of 40 white New Zealand rabbits were included in a penetrating posterior ocular injury model that was consisted of a 5-mm circumferential incision placed 8 mm behind the limbus at the supratemporal quadrant. They were randomly divided into two groups. The rabbits in Group 1 (n = 20) received 1.25 mg (0.05 mL) of intravitreal bevacizumab via pars plana injection and those in Group 2 (control group, n = 20) received 0.05 mL of intravitreal balanced salt solution. On Day 28, the eyes were enucleated and evaluated by gross inspection and light microscopy. Clearance time of vitreous hemorrhage, presence of fibrous proliferation or retinal detachment, greatest linear dimension of fibrosis, and grade of fibrous extension were regarded as outcome measures. Nominal variables were evaluated by the chi-square or the Fisher's exact test; continuous variables were evaluated using the Mann-Whitney U test. RESULTS: At the end of the surgery, all the eyes had moderate (n = 9 and 7 in the case and control groups, respectively) or severe vitreous hemorrhage (n = 11 and 13 in the case and control groups, respectively) (P = 0.52). Average clearance time of vitreous hemorrhage was 3.42 ± 2.71 and 6.47 ± 3.58 days in bevacizumab and control groups, respectively (P = 0.01). The incidence of ophthalmoscopically visible fibrous proliferation was 31.6% in the bevacizumab group and 63.2% in the control group (P = 0.05). The greatest linear dimension of fibrosis was 0.91 ± 1.14 mm in the bevacizumab group and 2.00 ± 1.58 mm in the control group (P = 0.02). Retinal detachment rate was 11% (n = 2, all rhegmatogenous) and 21% (n = 4, 2 rhegmatogenous and 2 tractional) in the bevacizumab and control groups, respectively (P = 0.66). Choroidal congestion, optic disk edema, and macular edema were seen in 1 eye (5.5%) of the bevacizumab group, whereas they were found in 4 (22%), 4 (22%) and 3 (16.5%) eyes of the control group, respectively. These differences, however, did not reach statistical significance. CONCLUSION: This study showed that intravitreal injection of bevacizumab may reduce the extent of fibrovascular and/or fibrocellular proliferation and may accentuate the clearance of vitreous hemorrhage after an experimental model of posterior penetrating ocular injury in rabbits. These alterations may affect the long-term anatomical and/or functional success rate of posterior segment surgeries in these eyes.