Cone Type Research Articles

Design and analysis of radio frequency window for the China Fusion Engineering Test Reactor ion cyclotron range of frequency heating system.

The Ion Cyclotron Range of Frequency (ICRF) heating system of the China Fusion Engineering Test Reactor (CFETR) is intended to provide plasma heating with a minimum power output of 20MW, which demands the Radio Frequency (RF) window to possess a higher performance requirement. This paper presents the design of an RF window for the CFETR ICRF heating system and focuses primarily on the design and confirmation of its electromagnetic performance. The RF window can be effectively matched in the operating frequency range and has an S11 of under -59 dB. The geometry of the cone type ceramics was optimized to reduce the surface tangential electric field distribution. An analysis of the electric field distribution of the RF window at 50kV indicates that the pressure side was below 2.3 kV/mm and the vacuum side was below 1.3 kV/mm. Furthermore, a transmission line test bench with an open-terminated setup was constructed to conduct withstand voltage tests on the mockup, and the results showed that the mockup could withstand 62kV for 2s and 47kV for 120s.

Unique 3D preservation of Rhuddanian (Silurian) Callograptidae (Gorny Altai, Russia)

We studied a collection of the Silurian (Rhuddanian) multi-branched dendroids, including reticulate, benthic dendroid graptolites of the Callograptidae Hopkinson (in Hopkinson and Lapworth, 1875), from the Gorny Altai, Russia. Species of Dictyonema Hall, Koremagraptus Bulman, Callograptus Hall, and Desmograptus Hopkinson were identified and described. The graptolites are represented by in situ burial of colonies with 3D preservation of tubaria (= rhabdosomes). Complete (intact) colonies of dendroid graptolites are characterized by successive development stages: juvenile, neanic, ephebic (adults), while the general configuration of the tubarium changed from the proximal to distal. In a number of cases, later stage of colony development — the gerontic stage (senilis) is found. We carried out morphological analysis of dendroid graptolite tubaria (Callograptidae) of various development stages, showing eight morphotypes of the colonies, namely, the cylinder, disc, disc on a stem, hemisphere, cone, wineglass, blooming flower, and funnel type.

Invited Session III: Diversity in chromatic processing across the animal kingdom: Comparative connectomics reveals noncanonical wiring for color vision in human foveal retina.

The Old World macaque monkey and New World common marmoset provide fundamental models for human visual processing, yet the human ancestral lineage diverged from these monkey lineages over 25 Mya. We therefore asked whether fine-scale synaptic wiring in the nervous system is preserved across these three primate families, despite long periods of independent evolution. We applied connectomic electron microscopy to the specialized foveal retina where circuits for highest acuity and color vision reside. Synaptic motifs arising from the cone photoreceptor type sensitive to short (S) wavelengths and associated with "blue-yellow" (S-ON and S-OFF) color-coding circuitry were reconstructed. We found that distinctive circuitry arises from S cones for each of the three species. The S cones contacted neighboring L and M (long- and middle-wavelength sensitive) cones in humans, but such contacts were rare or absent in macaques and marmosets. We discovered a major S-OFF pathway in the human retina and established its absence in marmosets. Further, the S-ON and S-OFF chromatic pathways make excitatory-type synaptic contacts with L and M cone types in humans, but not in macaques or marmosets. Our results predict that early-stage chromatic signals are distinct in the human retina and imply that solving the human connectome at the nanoscale level of synaptic wiring will be critical for fully understanding the neural basis of human color vision.

Poster Session II: Variation of cone spectral composition in the macula.

Cone spectral composition is central to the study of color vision and retinal development. There is a lack of information on the spatial distribution of L and M-cones in the macula given that there are no histological methods to separate them. To overcome this gap, cones were spectrally classified using adaptive optics OCT-based optoretinography in human subjects and their variation was described in the macula. To date, we have classified ~130000 total cones in 9 subjects across 79 regions of interest (ROI), with a maximum of 16 retinal eccentricities per subject spread along the 4 cardinal meridians. In 2 two subjects, the variation in cone spectral topography in both eyes was compared. The L: M cone ratio decreased in the foveal slope (0.4°- 1°) but remained relatively uniform in the parafovea from 1.5°- 10° eccentricity. The % S-cones and S-cone density were consistent with prior histology (Curcio et al. 1991). No significant differences were observed in the fellow eyes of the same subject or the distribution of cone types across the 4 cardinal meridians. Decreased L: M cone ratio in the foveal slope suggests earlier differentiation of M-cones than L-cones. The stable L: M cone ratio in the parafovea suggests that the greater fall off in chromatic versus achromatic vision with eccentricity is not explained by cone spectral composition, but is rather attributed to pooling in downstream neurons.

Designing regression approach for mode frequency prediction of empty and filled steel silos

In this study the primary objective is to design prediction model for the free vibration analysis of thin circular cylindrical steel silos having various aspect ratios in empty and varying filled conditions for different types of closures. A finite element method (FEM) is used to carry out the free vibration analysis of steel silos. It is found that the effect of different aspect ratios slender, intermediate slender and squat steel silos is very significant for dynamic response of silo. The silos are considered having open, flat and cone type of closures at its top end. The clamped-free (cantilever) boundary condition is taken for this approach as actual silos are fixed at flat-base. The structural mass of thin cylindrical shell steel silo is made constant for a particular height and diameter. The eigenvalues of the thin cylindrical shell steel silos are extracted by using block Lanczos method. The free vibrations of thin cylindrical shell steel silo with different aspect ratios, radius to thickness ratio are studied. From the present studies it is seen that as aspect ratio increases the fundamental frequency is reduced in empty silo. It is more in the case of squat silo. It can be seen that the fundamental frequency is less in the case of flat closure in all the aspect ratios of the silo. The frequency values are more in the case of cone closure is observed. Also as the mode number increases the modal frequency value increases. Further, as the filling level is increased the modal frequency also increases. Finally, regression approach is adopted for predicting the mode frequency of empty and filled silos for wide range of aspect ratios.

Contextualizing Disaster Phases Using Social Media Data: Hurricane Risk Visualizations during the Forecast and Warning Phase of Hurricane Irma

Abstract Common disaster-phase models provide a useful heuristic for understanding how disasters evolve, but they do not adequately characterize the transitions between phases, such as the forecast and warning phase of predictable disasters. In this study, we use tweets posted by professional sources of meteorological information in Florida during Hurricane Irma (2017) to understand how visual risk communication evolves during this transition. We identify four subphases of the forecast and warning phase: the hypothetical threat, actualized threat, looming threat, and impact subphases. Each subphase is denoted by changes in the kinds of visual risk information disseminated by professional sources and retransmitted by the public, which are often driven by new information provided by the U.S. National Weather Service. In addition, we use regression analysis to understand the impact of tweet timing, content, risk visualization and other factors on tweet retransmission across Irma’s forecast and warning phase. We find that cone, satellite, and spaghetti-plot image types are retweeted more, while watch/warning imagery is retweeted less. In addition, manually generated tweets are retweeted more than automated tweets. These results highlight several information needs to incorporate into the current NWS hurricane forecast visualization suite, such as uncertainty and hazard-specific information at longer lead times, and the importance of investigating the effectiveness of different social media posting strategies. Our results also demonstrate the roles and responsibilities that professional sources engage in during these subphases, which builds understanding of disasters by contextualizing the subphases along the transition from long-term preparedness to postevent response and recovery. Significance Statement Visual information is an important tool for communicating about evolving tropical cyclone threats. In this study, we investigate the kinds of visualizations posted by professional weather communicators on Twitter during Hurricane Irma (2017) to understand how visual information shifts over time and whether different visuals are more retweeted. We find that visual information shifts substantially in the days before Irma’s impacts, and these shifts are often driven by changes in Irma’s strength or forecast track. Our results show that cone, satellite, and spaghetti-plot visualizations are retweeted more frequently, while watch/warning imagery is retweeted less. These results help us to understand how visual information evolves during predictable disasters, and they suggest ways that visual communication can be improved.

Poster Session: Eliciting Color Percepts over Extended Fields through Cone-by-Cone Stimulation.

Purpose Human color vision is informed by the relative activations of the long-, medium-, and short-wavelength sensitive cones. We have developed a display that can produce a variety of color sensations using only a single wavelength of light, by programming the activity levels of the three cone types at population scales. Methods With an Adaptive Optics Scanning Laser Ophthalmoscope, we image the retina at 840 nm over a 0.9° x 0.9° field and track the eye's fixational motion in order to deliver discrete microdoses of 543 nm light to ~2500 individual cones per frame. Using each cone type's spectral sensitivity to 543 nm, we can recapitulate the relative activations consistent with colors that are distinct from the stimulating laser, resulting in percepts of uniform colored squares that appear stable in the world. Results Using stimulation from only 543 nm light, we can elicit color percepts ranging from green to red-orange in 2 subjects who have cone spectral types classified in a region of their retina. Additionally, we find through color matching data that the distinct color percepts are lost for intentional misdeliveries that exceed 30% of the cone diameter in both subjects. Conclusions These results demonstrate our system's ability to track the retina at high speed, stimulate with cone-level precision, and generate color percepts by directly programming the activity of the human cone mosaic. These technical capabilities provide a novel platform for studying color vision.

Seamless Parametrization with Cone and Partial Loop Control

We present a method for constructing seamless parametrization for surfaces of any genus that can handle any feasible cone configuration with any type of cones. The mapping is guaranteed to be locally injective, which is due to careful construction of a simple domain boundary polygon. The polygon’s complexity depends on the cones in the field, and it is independent of mesh geometry. The result is a small polygon that can be optimized prior to the interior mapping, which contributes to the robustness of the pipeline. For a surface of genus >0, non-contractible loops play an important role, and their holonomies significantly affect mapping quality. We enable holonomy prescription, where local injectivity is guaranteed. Our prescription, however, is limited and cannot handle all feasible holonomies due to monotonicity constraints that keep our polygon simple. Yet this work is an important step toward fully solving the holonomy prescription problem.

Design and Experiments of a New Internal Cone Type Traveling Wave Ultrasonic Motor

Design and Experiments of a New Internal Cone Type Traveling Wave Ultrasonic Motor

Development of a hand classification system for smart hand wearables

Research purpose: This study aimed to lay a research foundation for smart hand wearable design by classifying the right-hand data of 4545 adults aged 20 to 69. Further, to increase the practical applicability of the hand classification system, a hand type discrimination method and regression equations for the hand dimensions of each type were presented. Methods: This study statistically analyzed eighth Size Korea data with IBM SPSS Ver.26.0. Cluster analysis was performed to classify both finger length and circumference type. Discriminant analysis was conducted, yielding discriminant functions to aid potential smart hand wearable wearers in self-diagnosing their hand types. Linear regression analysis yielded regression equations for the detailed finger dimensions for the pattern-making of smart hand wearables. Results: The finger length type was categorized into four types: the Uphill type, Downhill type, Mountain type, and Horizon type for both men’s and women’s hands. The finger circumference type was categorized into two types, the Cone and Cylinder types, for both men’s and women’s hands. The discriminant function showed a mean accuracy rate of 89.9% and the regression equations a mean explanatory power of 72.9%. Conclusion: The hand classification system proposed in this study aimed to improve the fingertip fit of smart hand wearable products by analyzing the configuration of motion tracking gloves or haptic gloves. In addition, considering the practical applicability for both wearers and designers of smart hand wearables, a discrimination method of finger types for wearers’ self-diagnosis and regression functions of finger dimensions for designers’ pattern making were provided.

Cones generated by a generalized fractional maximal function

The paper considers the space of generalized fractional-maximal function, constructed on the basis of a rearrangement-invariant space. Two types of cones generated by a nonincreasing rearrangement of a generalized fractional-maximal function and equipped with positive homogeneous functionals are constructed. The question of embedding the space of generalized fractional-maximal function in a rearrangement invariant space is investigated. This question reduces to the embedding of the considered cone in the corresponding rearrangement-invariant spaces. In addition, conditions for covering a cone generated by a generalized fractional-maximal function by the cone generated by generalized Riesz potentials are given. Cones from non-increasing rearrangements of generalized potentials were previously considered in the works of M. Goldman, E. Bakhtigareeva, G. Karshygina and others.

Experimental and parametric analysis of exhaust heat exchanger used in thermoelectric generator

A thermoelectric generator system consists of an exhaust heat exchanger, a thermoelectric module, and water heat exchanger. Perfect heat exchangers recover as much heat energy as possible from engine exhaust with an acceptable pressure drop. The capacity and efficiency of the heat exchanger depend on its shape, type, and material of the heat exchanger. The main objective of this research was to perform a parametric analysis of the test section of the exhaust heat exchanger by using simulation tools. The simulation results were validated with the experimental results to ensure the performance of the simulation model. The performance of the test section was measured in relation to geometry, pressure drop, temperature distribution, fluid velocity, and temperature uniformity coefficient. The test section of 60 mm × 60 mm × 180 mm (F-type) shows a higher surface temperature with an allowable pressure drop than the other types of test section without inserts. The inserts played a vital role in enhancing the surface temperature distribution and uniformity coefficient. The cone type (G-type), cone-cylinder type (H-type), and cone-cylinder-cone type (I-type) inserts were used to improve the performance of the F-type test section. The G-type and H-type test sections of the exhaust heat exchanger have a high surface temperature, high-temperature uniformity, and allowable pressure drop.

Runner cone drilling and slotting to reduce vortex rope - induced pressure fluctuations in a Francis turbine

Pressure fluctuations caused by helical vortex rope in the draft tube is one of the main reasons for the instability of Francis turbines. Previous studies showed that drilling holes on runner cone can reduce the amplitude of pressure fluctuation. In this study, based on the runner cone which has been drilled one hole, two kinds of new runner cones are designed by means of drilling two more holes (2 holes runner cone) and drilling a slot (2 holes and 1 slot runner cone). Pressure fluctuation and flow pattern observation experiments as well as numerical simulations at partial load operation condition in a Francis turbine were carried out for the three types of runner cones. Analyses were performed to reveal the generation mechanism of the low frequency pressure fluctuations. The results showed that low frequency fluctuations are related to the cyclical rotation of helical vortex rope. Holes and slots on the runner cone have little impact on the efficiency of the Francis turbine. Slotting on the runner cone can reduce the amplitude of pressure fluctuation induced by vortex rope to a maximum of 29.41%. Hence, proper slotting on the runner cone can effectively reduce the low-frequency fluctuation caused by vortex rope in Francis turbines. These findings provide a new idea to improve the hydraulic instability of Francis turbines induced by vortex rope.

Comparative connectomics reveals noncanonical wiring for color vision in human foveal retina

The Old World macaque monkey and New World common marmoset provide fundamental models for human visual processing, yet the human ancestral lineage diverged from these monkey lineages over 25 Mya. We therefore asked whether fine-scale synaptic wiring in the nervous system is preserved across these three primate families, despite long periods of independent evolution. We applied connectomic electron microscopy to the specialized foveal retina where circuits for highest acuity and color vision reside. Synaptic motifs arising from the cone photoreceptor type sensitive to short (S) wavelengths and associated with "blue-yellow" (S-ON and S-OFF) color-coding circuitry were reconstructed. We found that distinctive circuitry arises from S cones for each of the three species. The S cones contacted neighboring L and M (long- and middle-wavelength sensitive) cones in humans, but such contacts were rare or absent in macaques and marmosets. We discovered a major S-OFF pathway in the human retina and established its absence in marmosets. Further, the S-ON and S-OFF chromatic pathways make excitatory-type synaptic contacts with L and M cone types in humans, but not in macaques or marmosets. Our results predict that early-stage chromatic signals are distinct in the human retina and imply that solving the human connectome at the nanoscale level of synaptic wiring will be critical for fully understanding the neural basis of human color vision.

Cone contrast test-HD: sensitivity and specificity in red-green dichromacy and the impact of age.

We report normative cone contrast sensitivity values, right-left eye agreement, and sensitivity and specificity values for the cone contrast test-HD (CCT-HD). We included 100 phakic eyes with color vision normal (CVN) and 20 dichromatic eyes (10 with protanopia and 10 with deuteranopia). The CCT-HD was used to measure L, M, and S-CCT-HD scores, and the right and left eyes were evaluated for agreement using Lin's concordance correlation coefficient (CCC) and Bland-Altman analysis to investigate the sensitivity and specificity of the CCT-HD based on diagnosis with an anomaloscope device. All cone types were in moderate agreement with the CCC (L-cone: 0.92, 95% CI, 0.86-0.95; M-cone: 0.91, 95% CI, 0.84-0.94; S-cone: 0.93, 95% CI, 0.88-0.96), whereas the Bland-Altman plots showed that the majority of cases (L-cone: 94%; M-cone: 92%; S-cone: 92%) fell within the 95% limits of agreement and showed good agreement. The m e a n±s t a n d a r d error L, M, and S-CCT-HD scores for protanopia were 0.6±1.4, 74.7±2.7, and 94.6±2.4, respectively; for deuteranopia, these were 84.0±3.4, 40.8±3.3, and 93.0±5.8, respectively; and for age-matched CVN eyes (m e a n±s t a n d a r d deviation age, 53.1±5.8 years; age range, 45-64years), these were 98.5±3.4, 94.8±3.8, and 92.3±3.4, respectively, with significant differences between the groups except for S-CCT-HD score (Bonferroni corrected α=0.0167, p<0.0167). The sensitivity and specificity of the CCT-HD were 100% for protan and deutan in diagnosing abnormal types in those aged 20 to 64years; however, the specificity decreased to 65% for protan and 55% for deutan in those aged >65 years. The CCT-HD is comparable to the diagnostic performance of the anomaloscope in the 20-64-year-old age group. However, the results should be interpreted cautiously in those ≥65 years, as these patients are more susceptible to acquired color vision deficiencies due to yellowing of the crystalline lens and other factors.

Analysis of q‐fractional coupled implicit systems involving the nonlocal Riemann–Liouville and Erdélyi–Kober q‐fractional integral conditions

The solutions to fractional differential equations are a developing area of current research, given that these equations arise in various domains. In this article, we provide some necessary criteria for the existence, uniqueness, and different types of Ulam stability for a coupled implicit system requiring the conditions for nonlocal Riemann–Liouville and Erdélyi–Kober q‐fractional integral conditions. The uniqueness and existence results for the suggested coupled system are demonstrated using Banach fixed point theorem and Leray–Schauder of cone type. We also explore the various types of stability using classical methods of nonlinear functional analysis. To verify the effectiveness of our theoretical outcomes, we study an interesting example.

Incommensurate helimagnetic structure of Ba(Fe1−xScx)12O19 determined by single-crystal neutron diffraction

Sc-substituted hexagonal ferrite $\mathrm{Ba}{({\mathrm{Fe}}_{1\text{\ensuremath{-}}x}{\mathrm{Sc}}_{x})}_{12}{\mathrm{O}}_{19}$ has an incommensurate helimagnetic structure. However, the incommensurate helimagnetic structure has not been sufficiently determined, and the mechanism via which the helimagnetism develops has not been studied. Time-of-flight-Laue single-crystal neutron diffraction measurements were performed at 4--6 K on single-crystal samples of $\mathrm{Ba}{({\mathrm{Fe}}_{1\text{\ensuremath{-}}x}{\mathrm{Sc}}_{x})}_{12}{\mathrm{O}}_{19}$ having Sc concentrations of $x=0$, 0.128, 0.153, and 0.193. The incommensurate helimagnetic structure was determined by analyzing the magnitude and direction of the ${\mathrm{Fe}}^{3+}$ magnetic moments at the five Fe1--Fe5 sites ($2a, 4e, 4{f}_{1}, 4{f}_{2}$, and $12k$). The development mechanism of the helimagnetic structure was discussed from the standpoint of superexchange interaction. The crystal structure analyses revealed that the Sc substitution enabled two significant events, namely, the coordination changes of ${\mathrm{Fe}}^{3+}$ and ${\mathrm{Sc}}^{3+}$ at the $\mathrm{Fe}2(4e)$ site, resulting in the shortened bond distances of Fe2-O1 and the preferred substitution of ${\mathrm{Fe}}^{3+}$ at the $\mathrm{Fe}4(4{f}_{2})$ site with ${\mathrm{Sc}}^{3+}$. The magnetic structure analyses revealed that the helimagnetic structure of $\mathrm{Ba}{({\mathrm{Fe}}_{1\text{\ensuremath{-}}x}{\mathrm{Sc}}_{x})}_{12}{\mathrm{O}}_{19}$ is a cone type whose base is in the $ab$ plane and height is in the $c\text{\ensuremath{-}}\mathrm{axis}$ direction. The magnetic moments of $\mathrm{Fe}2(4e), \mathrm{Fe}4(4{f}_{2})$, and $\mathrm{Fe}5(12k)$ are aligned with distinct angles, leading to the helimagnetic structure of $\mathrm{Ba}{({\mathrm{Fe}}_{1\text{\ensuremath{-}}x}{\mathrm{Sc}}_{x})}_{12}{\mathrm{O}}_{19}$, and can be explained by assuming that there is an antiferromagnetic superexchange interaction ${J}_{5}$ between $\mathrm{Fe}2(4e)$ and $\mathrm{Fe}5(12k)$ that is negligible in the $x=0$ crystal. The shorter bond distance of Fe2-O1 in Sc-rich crystals revealed by the crystal structure analyses enhances the superexchange interaction ${J}_{5}$. However, the ${\mathrm{Sc}}^{3+}$ preference for $\mathrm{Fe}4(4{f}_{2})$ weakens ${J}_{3}$ and ${J}_{4}$. The relatively strong ${J}_{5}$ leads to competition among the three superexchange interactions, ${J}_{3}, {J}_{4}$, and ${J}_{5}$, resulting in the development of the helimagnetic structure. These findings facilitate the understanding of the essentials of the basic magnetic material $\mathrm{Ba}{\mathrm{Fe}}_{12}{\mathrm{O}}_{19}$.

Investigation of the thermal and physicochemical behavior of two types of gutta-percha cones for back-filling the root canal.

Gutta-percha (Gp) is an inert thermoplastic polymer used as a filling to replace the dental pulp space, which has been reformulated to improve its three-dimensional sealing properties. Therefore, this study aimed to analyze the physical, chemical and thermal properties of two types of gutta-percha filling. As well as measuring the temperature distribution along the cone at the time of cutting through an in-situ test. Two commercially available brands of gutta-percha point were investigated: Conform Fit TM Gutta-Percha for ProTaper Gold® (PTG) (Dentsply Sirona), and Hygenic Gutta-Percha (Coltene whaledent). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were selected for the thermal characterization of materials, and Fourier Transform Infrared Spectroscopy (FT-IR) for the chemical analysis of Gp cones. Regarding temperature distribution, it was evaluated using a thermographic camera (FLIR ONE® PRO by MicroUSB P/N 435-0011-01) at 0 to 20 s after the cutting process (n=11/group). Both materials have three fusion endotherms associated with the three crystalline phases of Gp, with similar temperatures but enthalpies that differ by 60%, the fusion enthalpy being higher for Conform Fit. In the chemical characterization, elements such as Zn, C, O, Ba, S and Si were found in both materials but in different proportions. Regarding the content of fillers, the Conform Fit presented around 30% of Gp polymer and 25% for the Hygenic. The morphological characterization shows a microtexturized coating in the form of bars on a micrometric scale for the Conform Fit, which could favor a better three-dimensional seal. In addition to that, in heat transfer studies they showed greater temperature control. The characterization of the materials allowed us to see the variation in terms of their composition and configuration to the Gp cones of two commercial brands. These variations directly modify the thermal behavior of the material. Key words:Gutta-percha, Conform Fit, Infrared thermography, Differential Scanning Calorimetry, Infrared Spectroscopy.

Size variations in synaptic terminals among different types of photoreceptors and across the zebrafish retina

Photoreceptor synaptic terminals are responsible for transmitting visual information to downstream neurons. In vertebrate retinas, photoreceptor synaptic terminals are of different sizes and structures. The molecular mechanisms that underlie photoreceptor synaptic development are not clearly understood. Here, we have systematically examined the size variations in the synaptic terminals of cone and rod photoreceptors in the adult zebrafish retina. We reveal that the average cone pedicle sizes expand in the order of UV, blue, green, and red cones, echoing the increasing maximally sensitive wavelengths of the opsins expressed in the corresponding cone types. In addition, rod spherules are smaller than all cone pedicles. The terminals of each photoreceptor type also display distinct regional variations across the retina and between males and females. These findings establish the basis for using the zebrafish retina to study the molecular mechanisms that regulate the sizes and structures of photoreceptor terminals for proper visual functions.

Keratoconus in Thai population - a cross-sectional hospital-based study.

Studies in the epidemiology of keratoconus are limited in Southeast Asia. A study on the prevalence and characteristics of keratoconus in the Thai population could give a general idea of its impact. To study keratoconus prevalence in patients seeking refractive surgery and analyze the characteristics of keratoconus. Medical records from April 2015 to August 2018 were retrospectively reviewed. Keratoconus and keratoconus suspect prevalence in patients seeking laser vision correction were calculated. The characteristics of keratoconus patients were reviewed. The Amsler-Krumeich classification was used to determine the stages. Topographically, the types of cones were categorized into oval, nipple, pellucid marginal degeneration (PMD)-like, and astigmatic types. Keratoconus and keratoconus suspect prevalence were 1.66% and 0.68%, respectively. Out of the affected patients, 73.8% were male. The mean age at diagnosis was 25.25 ± 8.35 years. The presenting symptoms were blurred vision (87%) and itching (47%). Stage 1 was predominant, found in 39% of patients (followed by stages 2, 4, and 3, respectively). Ocular findings comprised the Munson sign (14.63%), the Rizutti sign (6.94%), Fleischer ring (28.14%), Vogt striae (24.95%), corneal scar (8.63%), prominent corneal nerve (2.81%), and corneal staining (7.69%). Mean uncorrected visual acuity (logarithm of the minimum angle of resolution [logMAR]) was 0.88 ± 0.64. Mean corrected visual acuity (logMAR) was 0.40 ± 0.49. Mean Q-value was -0.92 ± 0.63. The thinnest pachymetry was 459.39 ± 56.96 microns. The mean keratometry was 49.7 ± 6.64 diopters. Topographically, the types of cones were oval (57%), astigmatic (33%), PMD-like (5%), and nipple type (4%). Keratoconus prevalence among Thai patients seeking refractive surgery was 1.66%. Most patients were male and presented with the disease at a mild bilateral stage in their second decade of life.