Comparison of an aspheric monofocal intraocular lens with the new generation monofocal lens using defocus curve.

PURPOSE: The aim of this study was to compare the visual outcomes of two monofocal intraocular lenses (IOLs), with emphasis on the defocus curve. METHODS: A total of 116 consecutive eyes with cataract, undergoing phacoemulsification with IOL implantation were included in the observational case series, and divided into two groups. 71 eyes were implanted with Tecnis Eyhance and 45 with Tecnis 1 monofocal IOL. Eyes with ocular comorbidities, previous ocular surgeries and corneal astigmatism >1 Diopters (D) were excluded from the study. Complete ophthalmic evaluation including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected intermediate visual acuity (UIVA), corrected intermediate visual acuity (CIVA), uncorrected visual acuity (UNVA), corrected near visual acuity (CNVA) was noted and defocus levels ranging from -4.00 D to + 1.00 D were plotted postoperatively in both groups. RESULTS: Uncorrected intermediate visual acuity (UIVA) and uncorrected near visual acuity (UNVA) was significantly better in Tecnis Eyhance group compared to Tecnis 1 monofocal. Both the IOLs have similar performance for distance vision but visual acuity at intermediate and near is significantly better with Tecnis Eyhance compared to Tecnis 1 piece IOL. CONCLUSION: Tecnis Eyhance IOL with its better defocus curve, not only provides good distance, but intermediate vision as well. With significantly better visual acuity across the range of near and intermediate vision, Tecnis Eyhance IOL can prove to be a viable and reasonable option for patients who are more dependent on intermediate vision in daily activities.

International Values of Central Pachymetry in Normal Subjects by Rotating Scheimpflug Camera.

PURPOSE: In corneal refractive surgery, postoperative ectasia risk assessment routinely includes pachymetric analysis at the apex and thinnest point. We examined whether these data differ worldwide and constructed preliminary country-specific normative thresholds. DESIGN: This was a multicenter, cross-sectional study. METHODS: Using the Pentacam Eye Scanner (OCULUS GmbH, Wetzlar, Germany), we examined 1 randomly selected eye from each of 555 normal adults (8 countries, 6 continents), measuring the thinnest point location, central pachymetry (thinnest point, pupillary center, and apex), and the apex-thinnest point difference. International differences were assessed by 1-way analysis of variance. Normative thresholds were defined by 2- and 3-SD gates or Tukey method. RESULTS: The thinnest point averaged 0.44 mm temporal and 0.29 mm inferior to the apex. Individual thinnest points located more than 1.0 mm inferior represented fewer than 0.5% of normal corneas (>0.76 mm in the US subgroup). The mean thinnest-point pachymetry was 536 µm overall, and values less than 469 or 435 µm (-2 or -3 SD, respectively) would be expected in less than 2.5% or 0.15% of normal corneas, respectively. The thinnest-point pachymetry averaged 2 to 3 µm thinner than apical (range, 0-32 µm). Differences of greater than 8.5 µm would be expected in less than 0.5% of normal corneas overall. CONCLUSIONS: International differences were largely clinically insignificant. Nevertheless, it remains preferable to establish racial/geographic-specific normative values. We defined preliminary generalized and country-specific thresholds useful to the corneal refractive surgeon for identifying potentially abnormal corneas based on common pachymetric parameters, particularly the thinnest point by tomography.

International values of corneal elevation in normal subjects by rotating Scheimpflug camera.

PURPOSE: To examine whether clinically significant differences exist in corneal elevation data from a sampling of countries worldwide. SETTING: International multicenter. DESIGN: Evaluation of diagnostic test or technology. METHODS: One randomly selected eye of normal adults from 8 countries spanning 6 continents was examined using the Pentacam Eye Scanner. Anterior and posterior elevations were measured at the apex and thinnest point. Differences between countries were assessed by Kruskal-Wallis. Normative thresholds were defined according to the Tukey method. RESULTS: The study examined 1 eye of 555 patients. Median elevations were similar across countries. Upper limits of normal for collective international data were 3.5 µm, 6.0 µm, 7.5 µm, and 13.5 µm at the anterior apex, anterior thinnest point, posterior apex, and posterior thinnest point, respectively. These and country-specific thresholds were similar to normal values from previous data; however, country-specific thresholds flagged additional eyes in China, Egypt, and India. Those thresholds were 4.5 µm at the anterior thinnest point (China and Egypt), 7.4 µm at the posterior apex (India), and 11.0 µm and 12.0 µm at the posterior thinnest point (China and Egypt, respectively). CONCLUSIONS: In general, international variations were clinically insignificant; thus, current screening guidelines maintained their applicability. Notable exceptions were China, Egypt, and India, where country-specific thresholds may better reflect the test populations and minimize potential false negative results from screening. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes.

Anterior chamber depth in normal subjects by rotating scheimpflug imaging.

PURPOSE: Anterior chamber depth (ACD) is an important preoperative parameter in anterior segment surgery. Several factors are known to influence ACD, including race and geography. Our purpose was to sample data from various countries to characterize differences in ACD worldwide and, if any, assess their level of clinical significance. SETTING: International, multicenter. METHODS: Cross-sectional study. Using the Pentacam Eye Scanner (OCULUS GmbH, Wetzlar, Germany), we analyzed ACD measurements from 1077 eyes of 568 normal adults from nine countries spanning six continents. Differences between countries were assessed by comparison of 95% confidence intervals and by ANOVA. Normative thresholds were constructed at three standard deviations (SD) above and below the mean. RESULTS: Mean ACD was 3.11 mm overall, ranging from 2.91 mm (New Zealand) to 3.24 mm (United States). The ACD among New Zealanders was significantly shallower (P < .0001) than that among Chinese, Egyptians, Germans, Indians, and Americans. The maximum difference in the mean ACDs was 0.33 mm, between New Zealand and the United States. The shallowest 0.15% of normal ACD values occurred below 2.04 mm overall, ranging from 1.69 mm (New Zealand) to 2.42 mm (United States). The deepest 0.15% of normal ACD values occurred above 4.18 mm overall, ranging from 4.03 mm (Saudi Arabia) to 4.35 mm (Brazil). CONCLUSIONS: ACD did not vary significantly in the countries studied, with the notable exception of New Zealand. Surgeons should anticipate a greater likelihood of a shallow ACD when evaluating patients from New Zealand. Clinical examination and direct measurement of ACD are recommended. Finally, deep ACD has limited clinical utility in screening for keratoconus.

Assessment of central corneal thickness in normal, keratoconus, and post-laser in situ keratomileusis eyes using Scheimpflug imaging, spectral domain optical coherence tomography, and ultrasound pachymetry.

PURPOSE: To compare the central corneal thickness (CCT) in normal eyes, eyes with keratoconus, and eyes after laser in situ keratomileusis (LASIK) using 3 methods. SETTING: Cornea Clinic, Grewal Eye Institute, Chandigarh, India. METHODS: In this study, CCT was measured by sequential Scheimpflug imaging, spectral-domain anterior segment optical coherence tomography (AS-OCT), and ultrasound (US) pachymetry. RESULTS: Each of the 3 groups comprised 50 eyes. There were no differences between the 3 groups in age, sex, or intraocular pressure. In normal eyes, CCT was statistically significantly higher by US pachymetry (mean 525.8 microm +/- 41.4) [SD] than by Scheimpflug imaging (mean 519.4 +/- 40.9 microm) and AS-OCT (mean 517.9 +/- 41.5 microm) (both P<.001). In keratoconus eyes, CCT by US pachymetry (mean 446.4 +/- 57.9 microm) was statistically significantly higher than by Scheimpflug imaging (mean 439.6 +/- 62.1 microm) (P = .002) and AS-OCT (mean 441.8 +/- 58.4 microm) (P = .007). In post-LASIK eyes CCT by US pachymetry (mean 462.4 +/- 44.7 microm) was significantly higher than by Scheimpflug imaging (mean 457.9 +/- 33.6 microm) (P = .012) and AS-OCT (mean 455.4 +/- 43.2 microm) (P<.001). In all groups, CCT measured by Scheimpflug imaging and AS-OCT was similar. CONCLUSIONS: There was a statistically significant difference between Scheimpflug imaging and US pachymetry and AS-OCT, with US pachymetry measurements being consistently thicker. Thus, CCT should be interpreted in the context of the instrument used.