Randomized contralateral comparison of visual outcomes following implantation of two monofocal aspherical intraocular lenses after cataract surgery.

PURPOSE: To compare optical and visual performances of two one-piece aspherical implanted intraocular lenses (IOLs) following phacoemulsification cataract surgery in a contralateral eye study. METHODS: In this prospective randomized parallel-group study, 25 patients with bilateral age-related cataract were implanted in one eye with the EnVista IOL (MX60, Bausch & Lomb Corporations, Rochester, NY, USA) and the Acrysof IQ IOL (Acrysof IQ SN60WF, Alcon Surgical Laboratories, Fort Worth, TX, USA) in the other eye. Uncorrected and corrected distance visual acuity (UDVA, CDVA), refractive status, higher-orders aberrations (HOAs) in 5 and 6 mm pupil size, contrast sensitivity (CS) with and without glare, color vision status, and patient satisfaction were assessed in the two eyes at 1 and 3 months after surgery. RESULTS: There was no significant difference in CDVA (P > 0.99), UDVA (P = 0.46), spherical equivalent refractive error (P = 0.63), CS with and without glare across different spatial frequencies, color vision, and root mean square (RMS) of aberrometric values between the two IOLs after 3-month follow-up. Spherical aberration with 5 and 6 mm pupil sizes (P = 0.02) and horizontal coma with a 6 mm pupil size (P < 0.001) were lower with the EnVista IOL. Patient's satisfaction showed no cases of dissatisfaction, and most patients were highly or moderately satisfied with both IOLs. CONCLUSION: The visual and optical performance of eyes implanted with the EnVista IOL or the Acrysof IQ IOL was similar, although the aberration profile differed.

The effect of trabeculectomy on contrast sensitivity, corneal topography and aberrations.

PURPOSE: To investigate the effect of trabeculectomy on corneal topography, corneal sensitivity and aberrations. METHODS: Twenty-four eyes of 24 subjects with open-angle glaucoma who required glaucoma filtration surgery were assessed. The evaluation of corneal topography, corneal sensitivity and aberrations were done before the trabeculectomy procedure, 1 week and 1 month after the trabeculectomy. RESULTS: There were significant differences in cylindrical power (P = 0.02), contrast sensitivity at 12 cycle/degree spatial frequency (P = 0.04) as well as high order aberration (P = 0.04) and high order without spherical component (P = 0.02) following trabeculectomy. However, significant differences were found for keratometric results and Fourier index in 3 and 6 mm pupil diameters between pre- and post-trabeculectomy (P > 0.05). CONCLUSIONS: According to the findings of the current study, trabeculectomy affects contrast sensitivity at 12 cycle/degree spatial frequency, higher-order aberration and higher order without spherical component aberration 1 month after trabeculectomy. Being knowledgeable about these changes may lead to some advancement in post-surgical management of patients particularly in early stages following trabeculectomy.

Comparison of Keratoconus Cone Location of Different Topo/tomographical Parameters.

Purpose: To compare the corneal cone location on different maps and instruments, and their agreements, with elevation maps.Methods: In 90 left eyes with bilateral keratoconus, the apex of cone location was determined based on the maximum simulated keratometry (Kmax) location on the anterior sagittal curvature map by Pentacam HR, the maximum curvature on the mean curvature map by ATLAS 9000, most elevated point of the island of positive elevation relative to the best fit sphere on the front and back corneal elevation maps by Pentacam HR, and thinnest point on the thickness map by Pentacam HR and Orbscan, and the thinnest points on pachymetry and epithelial thickness maps by RTVue OCT.Results: There was a significant difference among the location on different maps along the x- and y-axes (p < .001). The lowest agreement with the cone apex on both front and back elevation maps was for the anterior sagittal curvature map and the highest agreement for the Pentacam thickness map. The majority of keratoconus cone apexes were displaced in the inferotemporal direction on the different maps except for the epithelial thickness maps.Conclusions: Despite the variability between different devices and methods; the thickness map on the Pentacam HR showed the highest correlation with the front and back elevation maps, while the RTVue epithelial thickness map showed the poorest correlation. Based on this study, epithelial thickness maps and anterior curvature maps should be utilized with caution to determine the location of the cone.

Corneal Biomechanical Properties in Varying Severities of Myopia.

Purpose: To investigate corneal biomechanical response parameters in varying degrees of myopia and their correlation with corneal geometrical parameters and axial length. Methods: In this prospective cross-sectional study, 172 eyes of 172 subjects, the severity degree of myopia was categorized into mild, moderate, severe, and extreme myopia. Cycloplegic refraction, corneal tomography using Pentacam HR, corneal biomechanical assessment using Corvis ST and Ocular Response Analyser (ORA), and ocular biometry using IOLMaster 700 were performed for all subjects. A general linear model was used to compare biomechanical parameters in various degrees of myopia, while central corneal thickness (CCT) and biomechanically corrected intraocular pressure (bIOP) were considered as covariates. Multiple linear regression was used to investigate the relationship between corneal biomechanical parameters with spherical equivalent (SE), axial length (AXL), bIOP, mean keratometry (Mean KR), and CCT. Results: Corneal biomechanical parameters assessed by Corvis ST that showed significant differences among the groups were second applanation length (AL2, p = 0.035), highest concavity radius (HCR, p < 0.001), deformation amplitude (DA, p < 0.001), peak distance (PD, p = 0.022), integrated inverse radius (IR, p < 0.001) and DA ratio (DAR, p = 0.004), while there were no significant differences in the means of pressure-derived parameters of ORA between groups. Multiple regression analysis showed all parameters of Corvis ST have significant relationships with level of myopia (SE, AXL, Mean KR), except AL1 and AL2. Significant biomechanical parameters showed progressive reduction in corneal stiffness with increasing myopia (either with greater negative SE or greater AXL), independent of IOP and CCT. Also, corneal hysteresis (CH) or ability to dissipate energy from the ORA decreased with increasing level of myopia. Conclusions: Dynamic corneal response assessed by Corvis ST shows evidence of biomechanical changes consistent with decreasing stiffness with increasing levels of myopia in multiple parameters. The strongest correlations were with highest concavity parameters where the sclera influence is maximal.

Masked comparison of two silicone hydrogel bandage contact lenses after photorefractive keratectomy.

PURPOSE: To compare the efficiency and safety of two bandage contact lenses after photorefractive keratectomy (PRK). METHODS: In this double-blind study, 45 patients (90 eyes) received PRK in both eyes and wore bandage contact lenses (BCLs), PureVision (Bausch & Lomb, Rochester, NY, USA) in one eye and PureVision2 (Bausch & Lomb, Rochester, NY, USA) in the other eye, randomly assigned. The medication regimen after surgery was the same for both eyes. The epithelial defect's size, conjunctival hyperemia and lens centration were graded objectively using slit-lamp biomicroscopy on days 1, 3 and 5 after surgery. Also ocular symptoms of discomfort including tearing, photophobia, foreign body sensation and visual fluctuations were assessed subjectively at each visit. RESULTS: The mean epithelial defect size on the first day after operation was similar in eyes fitted with PureVision (30.08 ± 5.30 mm²) and PureVision2 (30.25 ± 5.72 mm2) lenses. (p = 0.79) Contact lens deposits and bulbar hyperaemia on days 1 and 3 after PRK were similar between the two eyes, but were significantly greater on day 5 for PureVision2 lenses. (p = 0.02; p = 0.04 respectively) There was no difference in contact lens decentration, and discomfort symptoms including pain, tearing, foreign body sensation, photophobia and visual fluctuations between the eyes fitted with PureVision and PureVision2. (p > 0.05) CONCLUSIONS: PureVision and PureVision2 contact lenses are equivalent as bandage lenses in important aspects such as corneal re-epithelialization and subjective comfort., although PureVision2 led to a higher incidence of contact lens deposits and conjunctival hyperemia early post-PRK.