To investigate the mean values and standard deviations according to age, reliability, and correlation between different parameters of anterior chamber measurements using the Pentacam rotating Scheimpflug camera. Heidelberg IOL and Refractive Surgery Research Group, Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany. This prospective clinical study comprised 76 healthy volunteers (mean age 46.6 years +/- 16.8 [SD]). Three consecutive measurements were made of only 1 eye and anterior chamber depth (ACD), mean and minimum anterior chamber angle (ACA), and anterior chamber volume (ACV) were evaluated. Mean ACD was 2.93 +/- 0.36 mm, mean ACA was 34.81 +/- 5.05 degrees, minimum ACA was 29.99 +/- 5.53 degrees, and mean ACV was 160.3 +/- 36.81 mm3. Increasing age was associated with reduced ACD and ACV; however, mean and minimum ACAs were lowest in patients aged 40 to 59 years. Excellent correlation was found between ACD and ACV (R = 0.92). Anterior chamber depth and mean ACA correlated only moderately (R = 0.65). The correlation coefficient between ACD and minimum ACA was smaller (R = 0.58). There was no correlation between ACV and ACA (R = 0.37). Minor standard deviations were noted (ACD 0.02 +/- 0.02 mm, mean ACA 1.12 +/- 0.94 degrees, minimum ACA 2.04 +/- 2.67 degrees, and ACV 2.48 +/- 1.65 mm3). Using the Pentacam, it was possible to examine different parameters of the anterior chamber within a short period and with good reliability. The evaluation of the ACA in different positions can help to classify the potential risk for angle-closure glaucoma.

Introduction: Accurate assessment of the corneal shape is important in cataract and refractive surgery, both in screening of candidates as well as for analyzing postoperative outcomes. Although corneal topography and tomography are widely used, it is common that these technologies are confused. The aim of this study was to present the current developments of these technologies and particularly distinguish between corneal topography and tomography. Methods: The PubMed, Web of Science and Embase databases were the main resources used to investigate the medical literature. The following keywords were used in various combinations: cornea, corneal, topography, tomography, Scheimpflug, Pentacam, optical coherence tomography. Results: Topography is the study of the shape of the corneal surface, while tomography allows a three-dimensional section of the cornea to be presented. Corneal topographers can be divided into large- and small-cone Placido-based devices, as well as devices with color-LEDs. For corneal tomography, scanning slit or Scheimpflug imaging and optical coherence tomography may be employed. In several devices, corneal topography and tomography have been successfully combined with tear-film analysis, aberrometry, optical biometry and anterior/posterior segment optical coherence tomography. Conclusion: There is a wide variety of imaging techniques to obtain corneal power maps. As different technologies are used, it is imperative that doctors involved in corneal surgery understand the science and clinical application of devices for corneal evaluation in depth.

To investigate the mean values and standard deviations as well as the reliability of consecutive examinations of central and peripheral corneal thickness measurements according to age using the Pentacam rotating Scheimpflug camera (Oculus, Inc.). Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany. Seventy-six healthy volunteers were enrolled in a clinical prospective study. Three consecutive Pentacam measurements of 1 eye per subject were taken. Evaluated were the central corneal thickness (CCT), corneal thickness at 4 peripheral points (3.0 mm superior, inferior, nasal, and temporal), and the thinnest point of the cornea. The volunteers were then assigned to 3 groups to assess the influence of increasing age on the study parameters. The mean age of the subjects was 46.6 years +/- 16.8 (SD). The mean CCT was 539.62 +/- 31.87 microm. Peripherally, the corneal thickness was between 11% and 19% higher than centrally, with the superior cornea being the thickest followed by the nasal, the inferior, and the temporal cornea. The thinnest point was located in the inferotemporal quadrant in 92% of eyes and in the superotemporal quadrant in 8%. There was no correlation between age and corneal thickness. Minor mean standard deviations of consecutive measurements were noted in the corneal center (4.33 microm), increasing significantly toward the periphery (mean 8.31 microm). Increasing age was not associated with decreasing reliability. Using the Pentacam, it was possible to acquire information about corneal thickness across the entire cornea. No correlation was found between increasing age and change in peripheral or CCT. Good reliability was noted for pachymetry measurements decreasing slightly toward the periphery, which was independent of age.

PURPOSE: To assess the influence of decentration and aperture size on the optical quality of different intraocular lenses (IOLs) of the same material, body design, and refractive power using standardized optical bench testing. METHODS: Using an optical bench set-up, an aspheric monofocal (CT ASPHINA 409M; Carl Zeiss Meditec, Jena, Germany), an aspheric diffractive bifocal (AT LISA 809M; Carl Zeiss Meditec), and an aspheric diffractive trifocal (AT LISA 839M; Carl Zeiss Meditec) intraocular lens (IOL) were evaluated, each with the same distance power, body design, and material. Modulation transfer function (MTF) values were measured at spatial frequencies of 50 lp/mm and aperture sizes of 3 and 4.5 mm. Each IOL was measured while centered, then decentered by 0.25, 0.5, 0.75, and 1 mm. RESULTS: MTF values for the monofocal IOL at far focus with 3- and 4.5-mm aperture size were 0.80/0.80 with maximum reduction to 0.77/0.73 for 1-mm decentration, respectively. Centered IOL MTFs of the bifocal and trifocal IOLs were lower for the far focus at 0.46/0.41 and 0.39/0.26, with reduction at 1-mm decentration to 0.35/0.25 and 0.25/0.18, respectively. Values for near focus of the bifocal and trifocal IOLs reduced from 0.27/0.31 and 0.19/0.18 to 0.2/0.21 and 0.12/0.13, respectively. The trifocal intermediate focus MTF reduced from 0.15/0.10 to 0.12/0.08. MTF values of all three lenses decreased significantly under all conditions with decentration of 0.5 to 0.75 mm. CONCLUSIONS: Monofocal lenses were least negatively affected by decentration, with mean optical quality reduction of less than 10% for 1-mm decentration at physiological pupil sizes. For diffractive bifocal and trifocal lenses, optical quality at all distances was significantly reduced if decentration exceeded 0.75 mm, with intermediate focus showing the least reduction. [ J Refract Surg . 2017;33(12):808–812.]

A post-operative manifest refractive error as close as possible to target is key when performing cataract surgery with intraocular lens (IOL) implantation, given that residual astigmatism and refractive errors negatively impact patients’ vision and satisfaction. This review explores refractive outcomes prior to modern biometry; advances in biometry and its impact on patients’ vision and refractive outcomes after cataract surgery; key factors that affect prediction accuracy; and residual refractive errors and the impact on visual outcomes. There are numerous pre-, intra-, and post-operative factors that can influence refractive outcomes after cataract surgery, leaving surgeons with a small “error budget” (i.e., the source and sum of all influencing factors). To mitigate these factors, precise measurement and correct application of ocular biometric data are required. With advances in optical biometry, prediction of patient post-operative refractory status has become more accurate, leading to an increased proportion of patients achieving their target refraction. Alongside improvements in biometry, advancements in microsurgical techniques, new IOL technologies, and enhancements to IOL power calculations have also positively impacted patients’ refractory status after cataract surgery.

Background/aims To evaluate the effect of corneal collagen crosslinking with riboflavin and UV-A as a treatment option for postlaser in situ keratomileusis keratectasia. Methods Crosslinking was carried out in 22 eyes of 15 patients with iatrogenic keratectasia. Follow-up, according to a standardised protocol (uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), slit-lamp examination, pachymetry and topography), was performed preoperatively 1, 3, 6 and 12 months after crosslinking. Results The mean BCVA was 0.19 (SD±0.21) logMAR preoperatively, 0.25 (SD±0.17) 1 month, 0.20 (SD±0.20) 3 months, 0.18 (SD±0.21) 6 months and 0.15 (SD±0.14) 12 months postoperatively (statistically significant postop1–postop6, p=0.0335). The maximum k-readings were 44.12 (SD±3.97) preoperatively, 46.23 (SD±4.14) 1 month, 43.88 (SD±4.25) 3 months, 45.06 (SD±5.07) 6 months and 44.43 (SD±4.06) 12 months postoperatively (statistically significant preop–postop1, p=0.0281). Conclusion Crosslinking in patients with iatrogenic keratectasia stabilised the UCVA and BCVA as well as the maximum k-readings in our cohort. It seems to be a safe and promising procedure to stabilise the refraction and the corneal topography, and thus to stop the progression of visual loss, thereby avoiding or delaying disease progression and keratoplasty.