Aims-To report the appearances of cornea guttata and Fuchs' endothelial dystrophy from white light confocal microscopy. Methods-Seven eyes of four consecutive patients with cornea guttata were prospectively examined. Of the seven eyes, three also had corneal oedema (Fuchs' dystrophy). In vivo white light tandem scanning confocal microscopy was performed in all eyes. Results were compared with non-contact specular microscopy. Results-Specular microscopy was precluded by corneal oedema in one eye. In the remaining six eyes, it demonstrated typical changes including pleomorphism, polymegathism, and the presence of guttae appearing as dark bodies, some with a central bright reflex. In all seven eyes, confocal microscopy revealed the presence of round hyporeflective images with an occasional central highlight at the level of the endothelium. Changes in cell morphology and size were readily appreciated. Conclusion-By comparison with specular microscopy, the hyporeflective images with an occasional central highlight seen on confocal microscopy are consistent with the presence of guttae. Confocal microscopy may confirm the diagnosis of cornea guttata and Fuchs' endothelial dystrophy by demonstrating the presence of guttae. This technique is especially valuable in cases of corneal oedema, where specular microscopy may fail to visualise the endothelium. However, specular microscopy should remain the method of choice to evaluate the endothelium, principally because it is easier to use. (Br J Ophthalmol 1999;83:185-189) Corneal guttae consist of focal accumulation of collagen at the posterior surface of Descemet's membrane.1 They are probably secreted by abnormal endothelial cells and may appear as a result of aging. Guttae are characteristic for Fuchs' endothelial dystrophy, which is a familial dominantly inherited disorder, also characterised by corneal oedema.2 Usually the condition is bilateral, although asymmetric presentation is not uncommon. When corneal oedema is absent and only guttae are present, the condition is called cornea guttata.The endothelium is usually best examined by specular microscopy. However, confocal microscopy allows superior image contrast and vertical and lateral resolution, compared with conventional imaging methods.3-13 Because of its ability to focus the light source and the image on the same focal plane, it allows real time in vivo assessment of the diVerent layers of the cornea, including the endothelial layer. Therefore, it may be an alternative method in evaluating cornea guttata or Fuchs' endothelial dystrophy.In the current study, we analysed the appearances of cornea guttata and Fuchs' dystrophy from confocal microscopy and compare the technique with non-contact specular microscopy.

Citation: El-Fayoumi D, Badr Eldine NM, Esmael AF, Ghalwash D, Soliman HM. Retinal nerve fiber layer and ganglion cell complex thicknesses are reduced in children with type 1 diabetes with no evidence of vascular retinopathy. Invest Ophthalmol Vis Sci. 2016;57:5355-5360. DOI: 10.1167/iovs.16-19988 PURPOSE. To determine whether type 1 diabetes (T1DM) in children with a mean age of 12.21 6 3.04 years affects the retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) when compared to age-and sex-matched healthy children.METHODS. Forty-six children with T1DM with no diabetic retinopathy (DR) and 50 normal ageand sex-matched controls underwent full clinical ophthalmic and spectral-domain optical coherence tomography (SD-OCT) examination. Using RTVue Fourier-Domain OCT (version 6.11.0.12) average, superior, and inferior RNFL and GCC thicknesses (in lm) were measured. Mean values of patients and the control group were compared. RESULTS.In children with T1DM with no DR, the mean average RNFL thickness was 110.9 lm 6 10.46, and the mean GCC thickness was 95.59 lm 6 5.13; both were significantly thinner than the control group (115.62 lm and 99.30 lm, respectively). The retinal nerve fiber layer and GCC thickness showed no correlation to either age of onset, duration of the disease, or glycosylated hemoglobin (HbA1c). A positive correlation was found between the daily insulin dose and the average RNFL thickness (r ¼ 0.378, P ¼ 0.01). The average GCC in children with dyslipidemia was thinner than those with normal lipid profile (91.29 6 6.46 lm, 97.11 6 3.59 lm, respectively) with a P value of 0.011. CONCLUSIONS.Thinning of the RNFL and GCC in children with T1DM with no DR compared to healthy controls suggests that neurodegenerative changes occur in the absence of vascular changes. It also shows that neurodegeneration is not related to either disease duration, onset, or control.

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Synchronous generators in power systems are commonly equipped with Power System Stabilisers (PSS) to provide damping signals following disturbances. The design parameters of the PSS are load-dependent. The main objective of this paper is to design a simple robust PSS that can properly function over a wide range of operating conditions. The proposed compensator is designed by stabilising a finite number of characteristic polynomials that are obtained using Kharitonov theorem. The compensator's parameters are tuned using a swarm optimisation technique to ensure maximum relative stability. Simulation results illustrate satisfactory performance of the PSS as it is applied to the original non-linear system under wide loading conditions at lagging and leading power factors.