In eyes with suspect glaucoma, important decrease in PhNR amplitude is associated with small changes in peripapillary retinal and macular NFL thicknesses. These findings suggest that PhNR may be a useful and sensitive test in eyes with diagnostic dilemma, although further follow-up of such eyes is required for definitive confirmation.
BackgroundPosterior capsule opacification (PCO) is the most common post-operative complication associated with cataract surgery and is mostly treated with Nd:YAG laser capsulotomy. Here, we demonstrate the use of high-resolution spectral-domain optical coherence tomography (OCT) as a technique for PCO analysis. Additionally, we evaluate the influence of PCO types and the distance between the intraocular lens (IOL) and the posterior capsule (PC), i.e., the IOL/PC distance, on the total-pulse energy required for the Nd:YAG laser posterior capsulotomy.Methods47 eyes with PCO scheduled for the Nd:YAG procedure were examined and divided into four categories: fibrosis, pearl, mixed type and late-postoperative capsular bag distension syndrome. Using custom-made computer software for OCT image analysis, the IOL/PC distances in two dimensions were measured. The IOL/PC distances were compared with those of a control group of 15 eyes without PCO. The influence of the different PCO types and the IOL/PC distance on the total-pulse energy required for the Nd:YAG procedure was analyzed.ResultsThe total-pulse energy required for a laser capsulotomy differs significantly between PCO types (p = 0.005, Kruskal-Wallis test). The highest energy was required for the fibrosis PCO type, followed by mixed, pearl and late-postoperative capsular bag distension syndrome. The IOL/PC distance also significantly influenced the total-pulse energy required for laser capsulotomy (p = 0.028, linear regression). Lower total-pulse energy was expected for a larger IOL/PC distance.ConclusionsOur study indicates that the PCO types and the IOL/PC distance influence the total-pulse energy required for Nd:YAG capsulotomy. The presented OCT method has the potential to become an additional tool for PCO characterization. Our results are important for a better understanding of the photodisruptive mechanisms in Nd:YAG capsulotomy.
ABSTRACT.Purpose: Human anterior lens epithelial cells, attached to surgically isolated capsules, were found to contract upon stimulation. The purpose of this study was to characterize these contractions, which create gaps between cells, and to assess the underlying physiological mechanisms and their possible association with cataract formation. Methods: Lens capsules obtained during cataract surgery were stained with fluorescent dye Fura-2. Its fluorescence, upon excitation at 360 and 380 nm, was imaged to monitor changes in cell morphology and cytosolic free Ca 2+ concentrations ([Ca 2+ ] i ) in response to pharmacological stimulation by acetylcholine (ACh) and to mechanical stimulation by flow of saline or direct contact.Results: Epithelial cells contracted in approximately a third of preparations when stimulated by either ACh application, fluid movement or direct mechanical contact. Contractions started either before or at best simultaneously with the rise in [Ca 2+ ] i . Contractions also occurred when there was hardly any change in [Ca 2+ ] i upon application of physiological saline alone. The probability of contractions occurring did not differ significantly among cortical, nuclear and combined cortical + nuclear cataract. Conclusions: This study provides the evidence that contractions of the anterior lens epithelial cells take place in significant portion of human lens anterior capsule postoperative preparations after non-specific stimulation. Contractions are at least partially independent of changes in [Ca 2+ ] i . They can be mechanically induced, are localized and reversible and have a fast response and did not differ among different types of cataract. Physiological and clinical significance of this phenomenon remains to be elucidated.
Patients with ESCS show characteristic full-field ERG waveform abnormality, predominance of S-cone ERG activity, and thickening of the outer nuclear layer on SD-OCT. Moreover, they can also show abnormal post-photoreceptor connectivity through S-cone-related OFF-bipolar cell activity.
Purpose The defects in functional characteristics of lens capsule epithelial cells, can lead to the formation of the cataract, especially as cortical cataract. In the germinative zone of the lens the same progenitor cells, which also form the epithelil cells, differentiate also into the fiber cells, which make up the inside of the lens and through their activity also keep the lens clear. When their function is impaired the nuclear cataract ensues. We set out to make a preparation of the human anterior capsule from cataract surgery, which would allow functional studies of the physiology of capsule epithelial cells from patients with different types of cataract, using cell physiological methods. Methods We used the entire anterior capsules, with the cells still attached. Cell contacts were preserved and allowed the communication between the cells. In addition all the contacts to the basement membrane were largely preserved although some parts of the capsule were denuded of the epithelium – possibly due to manipulation during the surgery itself, or to epithelial cell apoptosis. The remaining cells were viable and the capsules usable for experimentation for at least a day when kept in a tissue culture incubator. For experimentation using an inverted microscope, the capsules were weighed down with a harp as the one used for electrophysiological experiments. In a series of pilot experiments the lens epithelial cells were loaded with fura‐2. Results They exhibited normal [Ca2+]i responses to agonist application such as Ach. Conclusion We conclude that this preparation represents a useful tool to study many aspects of the lens epithelial cell physiology.
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