Researchers from the University Eye Hospital in Munich, Germany, designed a prospective case series to compare the visual outcomes, alignment accuracy and surgical time between two methods of implanting toric intraocular lenses.
The study included 29 patients (57 eyes) having cataract surgery with implantation of a toric IOL (Torbi 709 M). They were randomly assigned to one of two groups based on the marking system used (manual or digital). Patients were included if they had age-related cataract and regular corneal astigmatism of 1.25 D or higher. Visual and refractive outcomes, as well as rotational stability, were evaluated. Vector analysis was performed to evaluate total astigmatic changes.
There were 28 eyes in the manual group and 29 eyes in the digital group. The mean toric IOL misalignment was significantly lower in the digital group than in the manual group (2.0 ±1.86 vs. 3.4 ±2.37 degrees; p=0.026). The mean deviation from the target induced astigmatism was significantly lower in the digital group (0.10 ±0.08 vs. 0.22 ±0.14 D; p=0.008). During surgery, the mean toric IOL alignment time was significantly shorter in the digital group (37.2 ±11.9 vs. 59.4 ±15.3 seconds; p=0.003). In addition, the mean overall time required to perform the surgery was significantly shorter in the digital group (727.2 ±198.4 vs. 1,110.0 ±382.2 seconds; p<0.001).
Based on the results of this study, the researchers say that the digital tracking approach for toric IOL alignment is an efficient and safe way to improve refractive outcomes. Furthermore, they say that image-guided surgery helps streamline the workflow in refractive cataract surgery.
J Cataract Refract Surg 2017;43:1281-1286
Mayer WJ, Kreutzer T, Dirisamer M, et al.
Lamina Cribrosa Thickness in Patients with Keratoconus
In a cross-sectional, observational study comprising 45 patients with keratoconus and 56 healthy subjects, researchers from the department of ophthalmology at the Kayseri Training and Research Hospital in Kayseri, Turkey, evaluated the thickness and depth of the lamina cribrosa in the optic nerve head region of the eyes in patients with nonglaucomatous keratoconus to compare the thickness and depth with those of age-matched controls. Analysis of LC imaging was performed using spectral-domain optical coherence tomography. Data collected included spherical equivalent, central corneal thickness, axial length, intraocular pressure and keratometry.
Eyes with keratoconus had significantly thinner LC (174.9 ±11.4 vs. 249.1 ±4.9 μm, p<0.001) compared with control-group eyes. There was no statistically significant difference in the depth of LC between the keratoconus and control groups (p=0.3). Multivariable analysis, controlled for age and sex, showed that the thickness of LC significantly correlated with central corneal thickness (p<0.001). This association persisted (p<0.001) after controlling for intraocular pressure, in addition to age and sex. There were no significant correlations with other factors, including the spherical equivalent (p=0.93) and keratometry (p=0.46).
The researchers note that the study showed that optical coherence tomography measurement of LC revealed thinner LC for patients with keratoconus compared with healthy controls, and speculate that the structural properties of the cornea may be related to the optic nerve.
Akkaya S, Küçük B.