Unoperated Eyes Research Articles

Scheimpflug Camera Measurement of Anterior and Posterior Corneal Curvature in Eyes With Previous Radial Keratotomy

To compare the anterior and posterior corneal curvature in eyes with previous radial keratotomy (RK) to normal unoperated eyes. In this retrospective observational case series, 29 eyes from 29 consecutive patients were analyzed and compared to a control group of 71 unoperated eyes. Corneal imaging was obtained by a rotating Scheimpflug camera (Pentacam, Oculus Optikgeräte GmbH). Anterior and posterior corneal curvature radii were measured at the 3-mm zone. The mean anterior and posterior corneal radii were 9.54 ± 0.89 and 8.54 ± 1.01 mm, respectively, both values being significantly higher than in the control group (7.81 ± 0.28 and 6.40 ± 0.24 mm, respectively, P<.0001). The mean anterior-to-posterior corneal curvature ratio was 1.12 ± 0.07, a value significantly lower than in the control group (1.22 ± 0.03, P<.0001). Mean corneal flattening was more evident in the posterior (33.44%) than in the anterior (22.15%) corneal curvature. The mean keratometric index, as calculated with the Gullstrand equation for thick lenses, was 1.3319 ± 0.0026, a value significantly higher than in the control group (1.3281 ± 0.0011, P<.0001). Linear regression detected a significant and directly proportional relationship between the number of radial incisions and flattening of both corneal surfaces (P<.0001). After RK, both corneal surfaces flatten but do not deform in parallel as commonly accepted, as shown by the fact that the anterior-to-posterior corneal curvature ratio decreases. This finding invalidates the standard keratometric index and thus has relevant implications for intraocular lens power calculation in RK eyes.

Comparison of Goldmann applanation and dynamic contour tonometry before and after cataract surgery

To validate changes in intraocular pressure (IOP) after phacoemulsification with intraocular lens (IOL) implantation without pressure-lowering surgery in previously unoperated eyes of normal and glaucoma patients. University Eye Clinic, Otto-von-Guericke-University, Magdeburg, Germany. Cohort study. The IOP in both eyes of patients was determined by Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT) 1 to 2 days before and after uneventful unilateral surgery. Central corneal thickness was used to correct raw GAT readings. Of the 50 patients having unilateral phacoemulsification, 29 had had cataract extraction in the contralateral eye. The mean baseline IOP was 17.4 ± 4.4 mm Hg (GAT) and 16.6 ± 2.9 mm Hg (DCT). Postoperatively, the GAT IOP decreased to 16.4 ± 6.5 mm Hg and the DCT IOP increased slightly to 17.1 ± 4.1 mm Hg. The mean tonometer difference (ΔIOP = GAT - DCT) amounted to ΔIOP(pre) = +0.75 ± 2.69 mm Hg in phakic eyes and ΔIOP(post) = -0.70 ± 3.76 mm Hg in pseudophakic eyes (P=.0011). Consistent results were found in pairs of phakic eyes and pseudophakic eyes (mean IOP 18.0 ± 4.8 mm Hg [GAT] and 17.0 ± 3.3 mm Hg [DCT]). In fellow eyes, the mean GAT reading was 13.4 ± 4.4 mm Hg and the mean DCT value, 14.8 ± 2.4 mm Hg. ΔIOP(phakic) was +1.04 ± 2.75 mm Hg and ΔIOP(pseudophakic) was -1.48 ± 2.78 mm Hg (P=.00000021). The GAT IOP readings in pseudophakic eyes seemed to be falsely low. Hence, special attention in the screening, diagnosis, and management of glaucoma is necessary.

Comparison of Parafoveal Retinal Thickness in Eyes with Idiopathic Macular Hole to that with Rhegmatogenous Retinal Detachment after Vitrectomy

Background:The foveal contour is asymmetrical in the horizontal optical coherence tomographic (OCT) images in idiopathic macula holes (IMHs) successfully closed by pars plana vitrectomy (PPV). The purpose of this study was to compare the parafoveal retinal contour after PPV followed by gas tamponade for IMHs to that after vitrectomy for rhegmatogenous retinal detachment (RRD). Design:Retrospective study. Participants:Eleven eyes of 11 IMH patients and 10 eyes of 10 RRD patients who underwent PPV. Methods: The internal limiting membrane (ILM) was stained with indocyanine green and peeled in the IMH group but not in the RRD group. The postoperative retinal thickness was measured by spectral-domain OCT. Main outcome measures:The parafoveal thicknesses of the operated eyes were compared to the corresponding areas of the fellow un-operated eyes. Results: In the IMH group, the average postoperative thickness of the temporal sector was 312.6 μm and that of the corresponding area of the fellow eyes was 330.2 μm (P <0.05). Similarly, the thickness of the nasal sector was 362.6 μm and that of the fellow eyes was 345.8 μm (P<0.05). These differences were not observed in the RRD group. Additional measurements showed that the inner retinal layer was thinner in the temporal retina and the outer retinal layer was thicker in the nasal retina in the IMH group. Conclusions:The postoperative asymmetrical foveal contour was observed in only the IMH group. We suggest that these alterations were caused by procedures, such as ILM peeling, rather than the gas tamponade.

Normal conjunctival flora and their antibiotic sensitivity in Omanis undergoing cataract surgery

Purpose:To evaluate the normal conjunctival flora and to ascertain their sensitivity to antibiotics.Materials and Methods:Prospective study was undertaken with 56 patients scheduled for cataract surgery. In each of these patients, conjunctival swab was taken from both eyes before instilling any antibiotic drops or local anesthetics and were sent for culture sensitivity by inoculating the samples in blood agar plates. The un-operated eyes served as controls for the study. The results were tabulated and analyzed by applying confidence intervals at 95% confidence limits.Results:Of the 112 eyes studied, positive cultures were obtained from 54 eyes (48.3%) preoperatively, and included both operated and control eyes. Coagulase-negative staphylococcus was isolated in 44 eyes (81.5%). Maximum sensitivity was found with vancomycin, gentamycin, chloramphenicol, and ciprofloxacin and maximum resistance with fusidic acid, penicillin, and oxacillin.Conclusion:We conclude that coagulase-negative staphylococcus are the most common bacteria isolated from the conjunctival sac, and vancomycin followed by gentamycin and ciprofloxacin are most effective against normal conjunctiva l flora, and fusidic acid the most ineffective of all the antibiotics tested.

Development of a surgical approach for a wide-view suprachoroidal retinal prosthesis: evaluation of implantation trauma

Our research goal is to develop a safe, reproducible surgical approach for implantation of a wide-field retinal stimulating array. The aim of this study was to evaluate the pathological response to acute implantation of a functional prototype electrode array in the suprachoroidal space. The surgical techniques to implant a 72 platinum electrode array fabricated on 8 × 13 × 0.4mm polyimide and silicone substrate were developed in a pilot study in anesthetized cats. For the main study, nine eyes were implanted in vivo and unoperated eyes were used as controls. Surgery consisted of a temporal approach with a full-thickness scleral incision 5mm posterior to the limbus. A suprachoroidal "pocket" was created, the electrode array inserted to sit beneath the area centralis, and placement was confirmed visually. The eyes were collected subsequently for histopathology. The array was consistently inserted into the suprachoroidal space beneath the area centralis in nine eyes. There was a significant hemorrhage in two cases where implantation was complicated by choroidal congestion. Retinal folding occurred only when the array tip was within 2.6mm of the optic disc (p < 0.01). There was choroidal incarceration at the incision in six eyes and scleral distortion at the array edges in five. No cases were found where the implant breached the retina, choroid, or sclera. A large stimulation array can be reliably inserted into the suprachoroidal space without trauma to the neuroretina. These findings suggest that this is an appropriate surgical approach for the placement of an electrode array for use in retinal stimulation.

Repeatability of automatic measurements by a new Scheimpflug camera combined with Placido topography

To assess the repeatability of anterior segment measurements performed by a Scheimpflug camera combined with Placido corneal topography (Sirius) in unoperated, post-refractive surgery, and keratoconus eyes. Private clinical ophthalmology practice. Evaluation of diagnostic test or technology. Three consecutive scans were acquired for each eye. The following parameters were evaluated: simulated keratometry, posterior corneal power, mean pupil power (ie, corneal power assessed by ray tracing through the anterior and posterior corneal surfaces), corneal asphericity, thinnest and apex corneal thickness, aqueous depth, anterior chamber volume, and corneal spherical aberration. Repeatability was assessed using test-retest variability, the coefficient of variation, and the intraclass correlation coefficient (ICC). Sixty-four unoperated eyes, 17 eyes that had myopic excimer laser surgery, and 13 eyes with keratoconus were analyzed. High repeatability was achieved for most parameters in the 3 groups, with an ICC higher than 0.99 for all measurements except posterior corneal power and mean pupil power in keratoconus (ICC, 0.868 and 0.976, respectively), anterior and posterior asphericity in normal eyes (ICC, 0.904 and 0.977, respectively), and spherical aberration in normal eyes (ICC, 0.806), post-refractive surgery eyes (ICC, 0.980), and keratoconus eyes (ICC, 0.981). The anterior segment measurements provided by the new Scheimpflug camera-Placido corneal topography system were highly repeatable and can be relied on in clinical routine and for research purposes. No author has a financial or proprietary interest in any material or method mentioned.

Computerized Scheimpflug densitometry as a measure of corneal optical density after excimer laser refractive surgery in myopic eyes

To evaluate changes in anterior corneal optical density and the refractive index after photorefractive keratectomy (PRK) using a rotating Scheimpflug system. Department of Ophthalmology, University Federico II, Naples, Italy. Comparative case series. Anterior corneal optical density was evaluated with a rotating Scheimpflug system at baseline and 3 months and 12 months after PRK in eyes with a refractive error between -6.00 diopters (D) and -12.00 D (study group). A control group of unoperated eyes with the same refraction range was used to calculate corneal optical density and the Gladstone-Dale constant in unoperated eyes using the Gladstone-Dale formula. In the study group, changes in the anterior corneal optical density were evaluated over time and variations in the anterior corneal refractive index were obtained using the Gladstone-Dale constant. The study group comprised 37 eyes and the control group, 200 eyes. In the study group, the mean anterior corneal optical density and refractive index, respectively, were 27.71 ± 4.39 and 1.360 ± 0.05 at baseline, 37.812 ± 12.31 and 1.491 ± 0.16 after 3 months (P<.001 compared with baseline), and 26.29 ± 4.93 and 1.341 ± 0.06 after 12 months (P=.03 compared with baseline). The mean corneal optical density in the control group was 27.71 ± 4.31 (SD), and the resultant Gladstone-Dale constant was 0.013. An early increase and a subsequent reduction in anterior corneal optical density and the refractive index were present in myopic eyes during 1 year after PRK.

Manganese porphyrin reduces retinal injury induced by ocular hypertension in rats

This study aimed to clarify the possible therapeutic benefit of preferential nitric oxide synthase (NOS) inhibition and catalytic antioxidant Mn (III) meso-tetrakis ( N-n-hexylpyridinium-2-yl) porphyrin (MnTnHex-2-PyP 5+) treatment in a rat model of elevated intraocular pressure (EIOP). Rats were randomly divided into different experimental groups which received either intraperitoneal MnTnHex-2-PyP 5+ (0.1 mg/kg/day), intragastric NOS inhibitor (S-methylthiourea: SMT; 5 mg/kg/day) or both agents for a period of 6 weeks. Ocular hypertension was induced by unilaterally cauterizing three episcleral vessels and the unoperated eye served as control. Neuroprotective effects of given treatments were determined via electrophysiological measurements of visual evoked potentials (VEP) while retina and vitreous levels of MnTnHex-2-PyP 5+ were measured via LC-MS/MS. Latencies of all VEP components (P 1, N 1, P 2, N 2, P 3) were significantly prolonged ( p < 0.05) in EIOP and returned to control levels following all three treatment protocols. Ocular hypertension significantly increased retinal protein nitration ( p < 0.001) which returned to baseline levels in all treated groups. NOS-2 expression and nitrate/nitrite levels were significantly greater in non-treated rats with EIOP. Retinal TUNEL staining showed apoptosis in all ocular hypertensive rats. The presented data confirm the role of oxidative injury in EIOP and highlight the protective effect of MnTnHex-2-PyP 5+ treatment and NOS inhibition in ocular hypertension.

Refractive surgery in anisometropic adult patients induce plastic changes in primary visual cortex

To prospectively study the effect of refractive surgery in the primary visual cortex of adult anisometropic and isometropic myopic patients. Two anisometropic and two isometropic myopic patients were examined with multifocal functional magnetic resonance imaging technique (mffMRI) before refractive surgery and at 3, 6, 9 and 12 months postoperatively. Two controls without refractive surgery were also examined with mffMRI in the beginning and in the end of the study. Anisometropic patients had only their more myopic eye operated to correct the anisometropia. The myopic isometropic patients had their both eyes operated. Operated anisometropic eyes showed 65% reduced amount of active voxels in foveal data at 12 months postoperatively compared with the preoperative situation. In unoperated anisometropic eyes, the corresponding value was 86% and in myopic patients and controls 31% and 1%, respectively. To confirm this finding, the number of activated voxels representing the innermost ring of the stimulus was also calculated, and an exactly similar phenomenon was encountered in the anisometropic patients. Both anisometropic patients improved the best-spectacle-corrected visual acuity in the operated eye after refractive surgery. Our results suggest that plastic changes may take place in the primary visual cortex of anisometropic adult patients after refractive surgery.

Repeatability of automatic measurements performed by a dual Scheimpflug analyzer in unoperated and post-refractive surgery eyes

To assess the repeatability of the anterior segment measurements performed with a dual Scheimpflug analyzer (Galilei) in unoperated and post-refractive surgery eyes. Private practice. Evaluation of diagnostic test. Three consecutive scans were acquired in unoperated eyes and in eyes that had excimer laser surgery for myopia. Unoperated eyes were enrolled from 3 subgroups: younger than 50 years, aged between 50 and 70 years, and older than 70 years. The following parameters were evaluated: simulated keratometry, posterior corneal power, total corneal power, anterior and posterior best-fit sphere radius, mean and thinnest central corneal thickness, anterior chamber depth and volume, horizontal and vertical corneal diameter, iridocorneal angle in the 4 quadrants, and corneal spherical aberration. Repeatability was assessed using analysis of variance (ANOVA), the coefficient of variation (COV), intraclass correlation (ICC), and test-retest variability. The study evaluated 45 unoperated eyes (n = 45) and 15 post-refractive surgery eyes (n = 15). Each age subgroup in the unoperated group comprised 15 eyes. The ANOVA did not detect significant differences between the 3 measurements for any parameter. The COV was less than 0.5% for corneal power measurements and less than 3.5% for all remaining parameters except spherical aberration (16.68%). The ICC was more than 0.99 for corneal power measurements and more than 0.94 for all remaining parameters. The anterior segment measurements provided by the dual Scheimpflug analyzer were highly repeatable. Repeatability did not change with age or after myopic photorefractive keratectomy or laser in situ keratomileusis.

Cataract Surgery Induces Retinal Pro-inflammatory Gene Expression and Protein Secretion

To investigate the effect(s) of cataract surgery on the expression of pro-inflammatory genes and proteins in the retina using an experimental rodent model. An extracapsular lens extraction was performed in one eye of C57BL/6 mice (n = 24); the contralateral unoperated eyes (n = 24) as well as eyes from unoperated animals (n = 9) served as controls. The neurosensory retina and retinal pigment epithelium (RPE)/choroid were collected postoperatively. Expression of genes involved in the acute inflammatory/injury response, including IL-1β, fibroblast growth factor, transforming growth factor β, chemokine CCL2, SDF-1, and complements C3, C4, and factor B (CFB), were examined by real-time PCR and, selectively, by immunohistochemistry. The expression of IL-1β and CCL2 genes was markedly upregulated (>20-fold, P < 0.01) in the neurosensory retina 30 minutes postoperatively and maintained for the 2-week postoperative period of observation; IL-1β expression was also upregulated in RPE/choroid. The expression of complement C3 (>5-fold) and CFB (>30-fold) genes in the neurosensory retina was also significantly upregulated (P < 0.01 in both cases). Increased IL-1b, CCL2, and CFB as well as enhanced C5b-9 immunostaining were observed by confocal microscopy. In rodents, lens extraction elicited an acute pro-inflammatory gene and protein response in the posterior segment of the eye, indicating induction of the inflammasome as well as complement activation, as occurs in the "danger" response. A similar response in humans might explain the pathogenesis of cataract surgery-associated retinal complications such as cystoid macular edema.

Digital Image Analysis to Characterize the Upper Lid Marginal Peak After Levator Aponeurosis Repair

Lid contour is important for eyelid symmetry, but clinical quantification can be difficult. The marginal peak is a major determinant of upper eyelid contour, and its horizontal position, relative to the mid-pupillary line, may be used as a measure of symmetry after surgery. This study used digital image analysis to assess the peak position in patients who had undergone levator aponeurosis repair. An unselected group of patients underwent anterior-approach levator aponeurosis repair, performed under local anesthesia by a single surgeon, using 3 6/0 Vicryl sutures to reattach the levator aponeurosis to the upper tarsus. Both before and 2-3 weeks after ptosis repair, digital photographs were taken in a fixed format and the images analyzed using NIH imaging software to assess the position of the upper eyelid peak. Comparisons were made between the pre- and postoperative measurements in the operated eye and between the operated eye and its fellow eye. Twenty people (8 male; 40%) underwent unilateral levator muscle resection (9 right eyes; 45%). In eyes before ptosis surgery, the peak was significantly more medially placed (median +0.17 mm) as compared with that of fellow eyes (median +0.80 mm) (p = 0.023). There was a significant temporal shift of the median peak after surgery, from +0.17 mm to +0.92 mm (p = 0.029). Although there was a minor nasal shift of peak in the unoperated eyes after contralateral surgery (median +0.80 mm to +0.64 mm), the peak positions for the 2 eyes were not significantly different at 2-3 weeks after aponeurosis repair (p = 0.22). Digital image analysis allows an objective assessment of the upper eyelid marginal contour after ptosis repair. A nasal shift in the upper eyelid marginal peak has been identified in ptotic eyes (as compared with the contralateral side) and, after successful ptosis repair, there is a significant temporal shift to match the unoperated fellow eye.

Accuracy of a dual Scheimpflug analyzer and a corneal topography system for intraocular lens power calculation in unoperated eyes

To evaluate the accuracy of the corneal power measurements by a dual Scheimpflug analyzer (Galilei) and a corneal topography system (Keratron) for intraocular lens (IOL) power calculation in unoperated eyes. Private practice. Case series. The IOL power was calculated for eyes having phacoemulsification and in-the-bag IOL implantation by entering into the Hoffer Q, Holladay 1, and SRK/T formulas 3 corneal power measurements: (1) simulated keratometry (K) by corneal topography, (2) simulated K derived by anterior corneal curvature only using the dual Scheimpflug analyzer, (3) total corneal power derived by anterior and posterior corneal curvatures through ray tracing using the dual Scheimpflug analyzer. The prediction error was calculated as the difference between the predicted and the measured refraction 1 month postoperatively. Forty-three consecutive patients were enrolled. The mean arithmetic error was zero for all combinations of measurements due to constant optimization. Using the Hoffer Q formula, the mean absolute prediction errors were 0.23 diopters (D) ± 0.22 (SD) for the corneal topographer simulated K, 0.21 ± 0.18 D for the Scheimpflug simulated K, and 0.27 ±0.20 D for the Scheimpflug total corneal power (P>.05). No statistically significant different results (compared with the Hoffer Q formula) were obtained with the Holladay 1 and SRK/T formulas. Both devices provided corneal power measurements that led to accurate IOL power calculation. The total corneal power by the dual Scheimpflug system is the first corneal power measurement shown to lead to accurate IOL power calculation without using the standard keratometric index. Drs. Savini, Barboni, and Carbonelli have no financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes.

Estimating Incidence of Vision-Reducing Cataract in Africa

To estimate the incidence of vision-reducing cataract in sub-Saharan Africa and use these data to calculate cataract surgical rates (CSR) needed to eliminate blindness and visual impairment due to cataract. Using data from recent population-based, standardized, rapid-assessment surveys, we calculated the age-specific prevalence of cataract (including operated and unoperated eyes) from surveys in 7 "districts" across Africa. This was done at 3 levels of visual acuity. Then we used the age-specific prevalence data to develop a model to estimate age-specific incidence at different visual acuities, taking into account differences in mortality rates between those with cataract compared with those without. The model included development of opacity in the first eye and second eye of people older than 50 years. The incidence data were used to calculate target cataract surgical rates. Incidence and CSR needs varied significantly in different sites and were lower in some than expected. Cataract surgical rates may depend on genetic, environmental, or cultural variations and will vary with population structure, which is not uniform across Africa. Africa should not be viewed as homogeneous in terms of cataract incidence or CSR needed. These CSR calculations should be useful for more appropriate planning of human resources and service delivery on the continent. The methodology can be applied to other population-based data as they become available to determine appropriate CSR targets.

Effect of Optic Nerve Sheath Fenestration on Papilledema of the Operated and the Contralateral Nonoperated Eyes in Idiopathic Intracranial Hypertension

To evaluate the effect of optic nerve sheath fenestration (ONSF) on papilledema grade in the operated eyes and the contralateral nonoperated fellow eyes in patients with idiopathic intracranial hypertension (IIH). Retrospective review. A total of 78 patients underwent ONSF, and 20 patients served as controls. Charts of patients with IIH who had ONSF at the University of Iowa Hospital and Clinics were reviewed for age, gender, body mass index, and clinical findings. Optic disc photographs were graded by a masked observer using the Frisén papilledema grading scale at preoperative baseline and postoperatively at 2 weeks, 3 months, 6 months, and 12 months follow-up. Wilcoxon signed-rank test was used to examine the change in papilledema grade in both operated and nonoperated eyes at each time point. Grade of papilledema. Sixty-two patients (52 women and 10 men) with a mean age of 32 years (range, 13-57 years) underwent unilateral ONSF. The median grade of papilledema for operated and nonoperated eyes was 3 and 2, respectively, at preoperative baseline. Postoperatively the grade was 2 in each eye at 2 weeks (P<0.0001 and <0.0002 for operated and nonoperated eyes, respectively), 1 in each eye at 3 months (P<0.0001 for both operated and nonoperated eyes), 1 in each eye at 6 months (P<0.0001 for both operated and nonoperated eyes), and 0.5 and 1 for operated and nonoperated eyes, respectively, at 12 months follow-up (P<0.0001 for both operated and nonoperated eyes). There was no significant difference in grade of disc edema or reduction of disc edema on the basis of age, gender, or body mass index. Unilateral ONSF significantly decreases the grade of papilledema in both ipsilateral (operated) and contralateral (unoperated) eyes. The reduction of the papilledema and the stability of visual field in the contralateral (nonoperated) eyes suggest that bilateral ONSF may not always be necessary in patients with bilateral visual loss and papilledema due to IIH.

Corneal Density with the Pentacam After Photorefractive Keratectomy

To measure corneal density and evaluate corneal haze in unoperated eyes and in eyes after photorefractive keratectomy (PRK). Forty-nine patients (91 eyes) who underwent PRK and 48 control patients (76 unoperated eyes) were measured with the densitometry program of the Pentacam Scheimpflug imaging system (Oculus Optikgeräte GmbH) (0=no clouding, 100=tissue completely opaque). Eyes were categorized as myopic or hyperopic (myopia group and hyperopia group), with subgroups defined as unoperated (unoperated myopia group and unoperated hyperopia group), postoperative clear corneas (clear cornea myopia group and clear cornea hyperopia group), and postoperative with haze (myopia haze group and hyperopia haze group). The ANOVA option of the Statistica 8.1 program package (StatSoft Inc) was used to compare subgroups. Maximum density of postoperative corneas with haze (myopia haze group, 46.2±16.2; hyperopia haze group, 50.2±25.8) was higher than in postoperative clear corneas (clear cornea myopia group, 29.9±8.7; clear cornea hyperopia group, 22.9±3.1), but maximum corneal density in the latter subgroups showed no difference compared with unoperated controls (unoperated myopia group, 25.1±2.4; unoperated hyperopia group, 22.8±3.2). Differences among subgroups were not found outside the 6-mm diameter ablation zone. In hazy myopic corneas, there was a strong decreasing density trend from the apex to the 3-mm radius (P<.001, R=-0.5), which continued towards the periphery at 4.5 mm (P=.019, R=-0.21). Hyperopic mild hazy corneas showed a density increase from the apex to 3 mm (P<.001, R=0.4), followed by a decrease towards the periphery (P<.01, R=-0.4). The densitometry program of the Pentacam can provide a useful objective measure of postoperative and other mild corneal haze.

Suppressive effect of astaxanthin on retinal injury induced by elevated intraocular pressure

The aim of this study was to clarify the possible protective effect of astaxanthin (ASX) on the retina in rats with elevated intraocular pressure (EIOP). Rats were randomly divided into two groups which received olive oil or 5 mg/kg/day ASX for a period of 8 weeks. Elevated intraocular pressure was induced by unilaterally cauterizing three episcleral vessels and the unoperated eye served as control. At the end of the experimental period, neuroprotective effect of ASX was determined via electrophysiological measurements of visual evoked potentials (VEP) and rats were subsequently sacrificed to obtain enucleated globes which were divided into four groups including control, ASX treated, EIOP, EIOP + ASX treated. Retinoprotective properties of ASX were determined by evaluating retinal apoptosis, protein carbonyl levels and nitric oxide synthase-2 (NOS-2) expression. Latencies of all VEP components were significantly prolonged in EIOP and returned to control levels following ASX administration. When compared to controls, EIOP significantly increased retinal protein oxidation which returned to baseline levels in ASX treated EIOP group. NOS-2 expression determined by Western blot analysis and immunohistochemical staining was significantly greater in rats with EIOP compared to ASX and control groups. Retinal TUNEL staining showed apoptosis in all EIOP groups; however ASX treatment significantly decreased the percent of apoptotic cells when compared to non treated ocular hypertensive controls. The presented data confirm the role of oxidative injury in EIOP and highlight the protective effect of ASX in ocular hypertension.

Corneal Ectasia After LASIK Despite Low Preoperative Risk: Tomographic and Biomechanical Findings in the Unoperated, Stable, Fellow Eye

To report a case of progressive corneal ectasia after LASIK with no detectable preoperative risk factors and to present three-dimensional corneal tomographic and biomechanical findings on the contralateral unoperated eye that would be considered low risk for ectasia and thereby a good LASIK candidate based on the Randleman Ectasia Risk Score System (ERSS). A case report, literature review, and description of novel screening criteria based on Pentacam (Oculus Optikgeräte GmbH) corneal tomography are presented as well as Ocular Response Analyzer (ORA, Reichert Instruments) corneal biomechanical analysis. Progressive corneal ectasia after LASIK of the operated left eye was confirmed by corneal topography. Scheimpflug imaging identified a meniscus-shaped LASIK flap with a central thickness of 165 μm and residual stromal bed thickness of 280 μm. Randleman ERSS score was 2 for the ectatic eye before LASIK and 1 for the current status of the unoperated eye, which remained stable with normal topography and no change in refraction for >5 years. Low corneal hysteresis (8.6 mmHg) and corneal resistance factor (7.5 mmHg) were found in the unoperated, nonectatic eye, along with a suspicious waveform sign of a second rebounded peak after second applanation. Pentacam average pachymetric progression was 1.09 (normal is <1.15); the Belin-Ambrósio overall deviation index was 1.99 (normal is <1.9). Three-dimensional corneal tomographic and ORA biomechanical measurements provide additional information that may help identify individuals at high risk for naturally occurring or iatrogenic corneal ectasia.

Mydriasis induced by sub-Tenon's ropivacaine injection in patients undergoing strabismus surgery

To investigate the effects of sub-Tenon's capsule ropivacaine injection on pupillary diameter in strabismus surgery. A total of 16 patients were randomly assigned to 2 groups. The ropivacaine group (R) received sub-Tenon's ropivacaine 1% (2.5-3 mL) injections. In the control group (C), general anesthesia was induced and a saline solution (2.5-3 mL) was injected in the sub-Tenon's capsule. Pupillary diameter was measured at baseline and 2 and 5 minutes from the injections. The effects of the injections were expressed as a ratio of final (5 minutes) versus basal diameter. A significant mydriasis occurred in the ropivacaine group when compared with the control group (Group R vs Group C ratio = 2.32, p < 0.0001) or with unoperated fellow eye (R vs unoperated eye ratio = 2.29, p < 0.0001). Ropivacaine in the sub-Tenon's capsule induces a mydriasis probably related to a pharmacological ciliary ganglion block.

Anterior Segment Measurements Using Pentacam and Orbscan II 1 to 5 Years After Refractive Surgery

To compare anterior segment measurements between Pentacam and Orbscan II after laser surface ablation. Corneal thickness, anterior elevation, posterior elevation, and anterior chamber depth more than 1 year after laser refractive surgery were measured using Pentacam and Orbscan II in 51 eyes that underwent laser epithelial keratomileusis (LASEK) and 21 eyes that underwent photorefractive keratectomy (PRK). As controls, the same comparisons were made in 52 unoperated eyes. Mean follow-up was 28.2 months in the LASEK group and 49.9 months in the PRK group. Mean corneal thickness using Pentacam was thicker than that using Orbscan by 10.4 microm in unoperated eyes, 22.6 microm in LASEK eyes, and 11.0 microm in PRK eyes, but the two devices showed good correlation in all groups. Mean anterior elevation was highly correlated between the two devices with 2.1-microm differences in LASEK eyes, but posterior elevation showed no correlation with significant discrepancies. Mean anterior chamber depth was 0.12-to 0.14-microm thicker with Pentacam than with Orbscan, and highly correlated in all groups. Pentacam and Orbscan showed good correlations in corneal thickness, anterior elevation, and anterior chamber depth despite some differences in mean values. The two devices, however, showed no correlation in posterior elevation measurements, a difference that was greater in the postoperative groups.