Purpose. To compare real-time intraocular pressure (IOP) during laser in situ keratomileusis (LASIK) in porcine eyes using two types of microkeratomes. methods. An interventional, prospective study of two microkeratomes: a Moria 2 (Moria group) and an IntraLase femtosecond laser (IntraLase Corp., Irvine, CA; IntraLase group). These devices were used to create lamellar corneal flaps in freshly enucleated porcine eyes. The IOP changes induced by the procedures were recorded with a reusable blood pressure transducer connected to the anterior chamber by direct cannulation. results. Seven porcine eyes were studied in each group. The IOP increased during the suctioning phase, reaching a mean of 122.52 ± 30.40 and 160.52 ± 22.73 mm Hg during the cutting phase in the Moria group (the total time in this group was 36.42 ± 7.48 seconds; suctioning required 21.42 ± 7.48 seconds and the cutting phase, 15 ± 2.88 seconds). In the IntraLase group, the IOP reached 89.24 ± 24.26 mm Hg during the suctioning phase and 119.33 ± 15.88 mm Hg during the intrastromal laser application (the total time was 92.85 ± 13.49 seconds; suctioning required 40.00 ± 9.57 seconds and the cutting phase 52.85 ± 5.66 seconds). Both IOPs during both phases differed significantly between the two groups (P = 0.01 for all comparisons). conclusions. Real-time IOP can be measured during LASIK using a transducer connected to the anterior chamber. The results showed a significant increase in IOP during the procedure in both groups, although with the IntraLase the IOP seemed to increase to a lesser extent than with the conventional mechanical microkeratome.
Objectives. To describe the past 20 years’ correction modalities for keratoconus and their visual outcomes and possible complications.Methods. A review of the published literature related to the visual outcomes and possible complications in the context of keratoconus management using nonsurgical procedures for the last 20 years (glasses and contact lenses) was performed. Original articles that reported the outcome of any correction modalities of keratoconus management were reviewed.Results. The most nonsurgical procedure used on keratoconus management is the contact lens fitting. Soft contact lenses and soft toric contact lenses, rigid gas-permeable contact lenses, piggyback contact lens system, hybrid contact lenses, and scleral and corneoscleral contact lenses form the contemporary range of available lens types for keratoconus management with contact lenses. All of them try to restore the vision, improve the quality of life, and delay surgical procedures in patients with this disease. Complications are derived from the intolerance of using contact lens, and the use of each depends on keratoconus severity.Conclusions. In the context of nonsurgical procedures, the use of contact lenses for the management of keratoconic patients represents a good alternative to restore vision and improve the quality of live in this population.
6 September 2013 in Graefe's Archive for Clinical and Experimental Ophthalmology
To determine the correlation between refractive and keratometric astigmatism in pseudophakic eyes. Vissum Madrid, Madrid, Spain. Case series. Consecutive eyes that had phacoemulsification with intraocular lens implantation during the first quarter of 2003 were evaluated. The refractive and keratometric astigmatism were compared 2 months postoperatively. The mean postoperative keratometric astigmatism (0.91 diopter [D] ± 0.67 [SD]) in the 121 eyes was statistically significantly higher than the mean postoperative refractive astigmatism (0.64 ± 0.72 D) (P<.0001). Regression analysis found a significant correlation between the refractive and keratometric errors of the J0 component (P<.001, r(2) = 0.29) and between the refractive and keratometric errors of the J45 component (P<.001, r(2) = 0.36) Keratometric astigmatism was responsible for about 30% of the refractive astigmatism in pseudophakic eyes. Other undetermined factors induce astigmatism in these cases.
This systematic review examines the use of eye-tracking devices in optometry, describing their main characteristics, areas of application and metrics used. Using the PRISMA method, a systematic search was performed of three databases. The search strategy identified 141 reports relevant to this topic, indicating the exponential growth over the past ten years of the use of eye trackers in optometry. Eye-tracking technology was applied in at least 12 areas of the field of optometry and rehabilitation, the main ones being optometric device technology, and the assessment, treatment, and analysis of ocular disorders. The main devices reported on were infrared light-based and had an image capture frequency of 60 Hz to 2000 Hz. The main metrics mentioned were fixations, saccadic movements, smooth pursuit, microsaccades, and pupil variables. Study quality was sometimes limited in that incomplete information was provided regarding the devices used, the study design, the methods used, participants' visual function and statistical treatment of data. While there is still a need for more research in this area, eye-tracking devices should be more actively incorporated as a useful tool with both clinical and research applications. This review highlights the robustness this technology offers to obtain objective information about a person's vision in terms of optometry and visual function, with implications for improving visual health services and our understanding of the vision process.