Features Of Keratoconus Research Articles

Keratoconus characteristics and associations: A cross-sectional keratoconus study in western India (CKSWI).

To study the clinical and tomographic characteristics and associations of keratoconus (KC) patients visiting a tertiary eye care hospital. This was a cross-sectional, observational study that included 242 newly diagnosed clinical KC patients. Detailed ocular and systemic history, visual complaints, habit of eye rubbing, best spectacle-corrected visual acuity (BSCVA), retinoscopy reflex, detailed slit-lamp examination and tomographic findings, and presence of any ocular and systemic associations were documented for the included patients. Severity of KC was further graded into stages 0, 1, 2, 3, and 4 according to the ABCD grading system. The most common visual complaint was blurred vision (82.64%), followed by itching (48.76%), tearing (43.80%), and photophobia (41.32%). A total of 44.62% of patients had the habit of eye rubbing and 4.54% had a family history of KC. Most common clinical signs were scissor reflex (94.21%), Rizutti's sign (77.27%), corneal protrusion (69.83%), and Fleischer ring (67.35%). A total of 14.05% of patients had stage 0, 42.15% had stage 1, 19.83% had stage 2, 18.60% had stage 3, and 5.37% had stage 4 KC. Of these patients, 70.25% had a BSCVA visual acuity of ≥6/12 or better; 26.45% had a BSCVA of ≥6/60 to <6/12; and 3.30% had a BSCVA of <6/60. Ocular allergies, atopy, and asthma were found in 32.32%, 4.96%, and 2.48% cases, respectively. This study gives an overview of the clinical findings of KC cases in western India. Our results suggest that use of retinoscopy should be promoted in early KC detection in primary eyecare screening programs.

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.

Comparing the natural progression and clinical features of keratoconus between pediatric and adult patients

To present the natural course of keratoconus (KC) and compare pediatric and adult patients. Design A retrospective cohort study. Setting Hospital-based. Patient Population In total, 152 patients (288 eyes) diagnosed with KC at Chang Gung Memorial Hospital, Taiwan, were included. Previously managed patients and those with missing optical data were excluded. Observation Procedures Patients were divided into pediatric (≤ 18 years) and adult (> 18 years) groups. Demographics, clinical data, and optical variables were collected, including corrected distance visual acuity (CDVA), refractive error, and keratometric readings (K). Main Outcome Measure Optical variables at the final follow-up before aggressive treatment. Results In total, 20 pediatric (37 eyes) and 132 adults (251 eyes) patients were eligible for this study. The mean follow-up time was 2.98 years. Male predominance was observed in both groups. Both groups had similar clinical characteristics and optical variables at the initial diagnosis. Pediatric patients progressed significantly more rapidly in refractive errors, including spheres and cylinders, spherical equivalence, steep K, and flat K during the follow-up. However, significant change between the two study groups was only seen in sphere refractive error spherical equivalence. Conclusion Pediatric patients had more rapidly progressive KC than adult patients, so early detection and frequent follow-up for prompt interventions are necessary for these patients.

Effects of rigid high gas-permeable contact lens wear on progression in patient with keratoconus

Wearing Rigid High Gas-Permeable Contact Lens (RGPCL) is a primary method of vision rehabilitation in keratoconus eyes. The aim of the study is to investigate the effects of using RGPCL on the topographical variations at the keratoconus progress. All patients had undergone ophthalmic examination including corneal topography, and their medical history and keratoconus characteristics were documented. Fifty-one eyes of those who wore RGPCL without any problems and 42 eyes of those who did not wear any lenses were evaluated retrospectively. It was accepted that the follow-up period was terminated when patients received any treatment or change lenses. The mean follow-ups were 36.5±12.7 and 38.4±14.6 months in the control and lens-wearing samples, respectively. The changes in topographic indices were compared from the baseline to the final visit. The difference between spectacle-best corrected visual acuity was not significant in both groups from baseline to final visit (p&gt;0.05). In the RGPCL wearing group, apical keratometric power ( Kmax ) increased from mean 51.86±3.70 diopter (D) to 52.54±3.85 D at the sagittal map in the following period, but this difference was not significant (p&gt;0.05). Similarly, in the control group, Kmax increased from mean 52.14±2.51 D to 52.94±3.02 D, and this difference was not significant (p&gt;0.05). Lens-wearing and control group mean keratometry values increased from 47.36±1.7 D and 47.17±1.65 D to 47.94±2.05 D and 47.74±1.76 D, respectively (p&gt;0.05). Pachymetry at the thinnest corneal point decreased significantly in both groups from baseline to final visit (p=0.008, p=0.01). In conclusion, the comfortable usage of RGPCL has no effect on the progression of keratoconus.

Keratoconus Characteristics Used in Randomized Trials of Surgical Interventions-A Systematic Review.

To investigate descriptions and inclusion criteria of keratoconus used in randomized trials assessing the efficacy of surgical and nonsurgical interventions. Systematic review: we searched (Pre-)Medline and the Cochrane Library from inception until December 2018 and checked the reference lists of included articles and reviews. We included randomized trials assessing the efficacy of any kind of keratoconus treatment. No language restrictions were imposed. We assessed articles against the inclusion criteria, extracted relevant data including any kind of keratoconus description, and examined the methodological quality. Searches retrieved 459 nonduplicate records, and we included 57 randomized controlled trials investigating 9 different surgical interventions with the most used primary outcome measure being maximum keratometry. Only 15 (26.3%) described eligibility parameters regarding keratoconus staging/classification, of which 12 studies used the Amsler-Krumeich classification. Eleven studies were published before 1997 (before publication of the Consolidated Standards of Reporting Trials statement), and none of these described the use of a classification. From 1997 onward, 15 of 46 studies (32.6%) described the incorporation of a classification system (P = 0.051). The average methodological quality of included trails was modest. The evidence from randomized trials, even after introduction of the Consolidated Standards of Reporting Trials statement, remains ill-formed regarding a careful definition of keratoconus. This is unfortunate because imprecisions regarding the specification of included patients preclude clinicians to assess applicability, that is, the extent to which they can use inferences drawn from study participants regarding efficacy and adverse events in the care of individual patients.

Tissue-Derived Biological Particles Restore Cornea Properties in an Enzyme-Mediated Corneal Ectatic Model.

Purpose: To investigate the impact of tissue derived biological particles on enzyme-mediated weakened corneas. Methods: Rabbit corneas were treated with enzymes to create an ex vivo ectatic model that simulated representative characteristics of keratoconus (KC). Porcine cornea, cartilage, and lymph node tissues were processed to remove most cellular components and cryomilled into microparticles. The KC corneas were cultured in medium containing the tissue-derived biological particles (TDP) overnight. The mechanical, thermal, ultrastructural changes, and gene expressions of corneal stromal cells were characterized to evaluate the effects of the TDP treatment. Results: The enzyme treatment significantly reduced corneal mechanics and thermal stability, and also disrupted the extracellular matrix ultrastructure. After culturing with TDP medium, the Young’s modulus of the modeled KC corneas increased by ~50%, comparable to normal cornea controls. Similarly, the thermal denaturation temperature of the corneas was restored. These findings also corresponded to a significant increase in collagen fibril density after TDP treatment. Furthermore, corneas cultured in TDP medium significantly downregulated expression of the pro-inflammatory gene Tnfα, and restored the expression of the key keratocyte markers Aldh, keratocan, and biglycan. Conclusions: Tissue-derived biological particles reinforce mechanical and thermal properties of corneal tissue in an ex vivo model of KC. Through this study, we demonstrate and characterize the previously unexplored impact of tissue-derived biological scaffolds on corneal biomechanics, thermal stability, and gene expression, presenting a potential new therapy for ocular disease.

Role of retinoic acid-related orphan receptor gamma transcription factor (RORɣ) in keratoconus pathology

Keratoconus (KC) is a complex, multifactorial, inflammatory disorder characterized by ectasia and steepening of the cornea, leading to visual impairment. The characteristic pathophysiological features of KC develop as a result of progressive dysregulation of the extracellular matrix proteins (collagens (COL) I and IV) and their regulators (lysyl oxidase (LOX) and matrix metalloprotease (MMP) 9) as well as an aberrant inflammatory cytokine profile. The abundance of pro-inflammatory cytokines, including IL-17, in the tear fluid of KC patients could potentially trigger pathogenic signalling cascades culminating in aberrant ECM remodeling through yet to be explored mechanisms. Traditionally, IL-17 has been ascribed to regulate Th-17 cell maturation and development of autoimmunity. However, since KC is a stromal disease with epithelial contribution, we tested if the corneal epithelium has the capacity to produce IL-17. We investigate the potential regulation of increased IL-17 in tears of KC patients by evaluating the levels of its regulator, the transcription factor retinoic acid-related orphan receptor gamma (RORg).

RARE ASSOCIATION OF KERATOCONUS IN THE CONTRALATERAL EYE IN A CASE OF DUANES RETRACTION SYNDROME

Duanes retraction syndrome is characterised by restriction of ocular motility, changes in palpebral fissure width and globe retraction. Keratoconus is a bilateral, progressive non-inflammatory corneal ectatic disease characterised by central or paracentral thinning and steepening causing irregular astigmatism. We report a case of rare association of DRS with keratoconus in the contralateral eye in a thirteen year old male child. The ocular motility revealed left DRS with exotropia. Corneal topography, based on new Scheimpflug and placido-disk analyser, revealed the findings consistent with features of keratoconus in the right eye. There were no associated systemic abnormalities. This case gives evidence of the importance of cycloplegic refraction which provided a clue towards suspecting keratoconus. It also highlightsthe fact that a patient with DRS should be examined thoroughly to rule out any associated ocular anomalies.

Pupillary Offset in Keratoconus and its Relationship with Clinical and Topographical Features

ABSTRACTPurpose: To evaluate the change in the location of pupillary center with corneal tomography in keratoconic patients, and determine the correlation of pupillary offset with clinical and topographical features of keratoconus.Methods: Ninety-one eyes of the 54 patients with keratoconus in different stages and 39 eyes of 39 refractive surgery candidates with normal corneas were included in our study. Ocular aberrations and the pupillary offset parameters (x-offset and y-offset) over a 5 mm (undilated) pupil were measured with a Sirius corneal tomographer. A correlation analysis among the pupillary offset parameters and the possible determinative variables (topographical and tomographical parameters, corneal aberrations and best corrected visual acuity) was performed.Results: The mean pupillary offset was significantly greater in the keratoconic eyes compared with the controls (p = 0.003), and the difference was mostly due to the y-offset (p = 0.03). There was no significant difference between the groups in the mean horizontal pupillary offset value (p = 0.07). Both the vertical and the total pupillary offset values correlated significantly (p < 0.0001) with the keratoconus stage (r = 0.58 and r = 0.51, respectively). They also correlated with the corneal aberrations, and negatively correlated with the visual acuity.Conclusions: The pupillary offset seems to correlate with the clinical and topographic features of keratoconus. It may be important to quantify its magnitude and direction in order to ensure correct centralization of the corneal procedures.

Presence of Fleischer ring and prominent corneal nerves in keratoconus relatives and normal controls.

To examine the occurrence of commonly known clinical signs of keratoconus (KC), i.e. Fleischer ring, prominent corneal nerves and thinning, among unaffected family members of KC patients and healthy control individuals. Data of both eyes of 117 relatives of KC patients having no manifest disease based on videokeratography indices (KC relatives), and 142 controls were used for Pearson correlation and t-test statistics. Correlation of Fleischer ring, prominent corneal nerves and central pachymetry data were tested with each other and with videokeratography indices (KSI, KISA, 3 and 6 mm Fourier asymmetry, and I-S). A moderate correlation was found between Fleischer ring and all examined topographical indices. Most important correlation was present with 6 mm Fourier asymmetry, and corneal pachymetry (r=0.272, P<0.001; r=-0.234, P=0.027, respectively). Similar correlations were found with prominent corneal nerves (r=0.234, P<0.001 for 6 mm Fourier asymmetry and r=-0.235, P=0.0265 for pachymetry). KC family members who exhibited Fleischer ring or prominent nerves had thinner and more asymmetric corneas than those without Fleischer ring or prominent corneal nerves (P<0.05 for pachymetry and topographic indices with t-test and Mann-Whitney rank sum test). Though rarely, Fleischer ring and prominent corneal nerves occurred among normal controls, indicating the existence of forme fruste cases in the normal population. Control subjects, who had corneal Fleischer ring or prominent nerves had corneas more similar to KC than other controls (t-test: increased KSI and KISA, P=0.048 and 0.012, respectively). In KC family members and healthy individuals, Fleischer ring and prominent corneal nerves are associated with features of KC and may suggest a possibility of forme fruste KC. Searching for the possible presence of Fleischer ring or prominent nerves on the cornea may help in the decision whether or not to diagnose subclinical KC in a borderline case.

Macular corneal dystrophy and associated corneal thinning.

To identify the molecular genetic cause of macular corneal dystrophy (MCD) in four probands, and characterize phenotypic similarities between MCD and keratoconus. We performed ophthalmological examination, Scheimpflug imaging (Pentacam, Oculus Inc.), histopathological examination of excised corneal buttons, and direct sequencing of the CHST6 coding region. Pentacam measurements were taken in six eyes of three probands. All showed diffuse corneal thinning with paracentral steepening of the anterior corneal surface that was graded as keratoconus by the integrated software, but without associated ectasia of the posterior corneal surface or regional thinning. Homozygous or compound heterozygous CHST6 mutations were identified in all cases, including two novel mutations, c.13C>T; p.(Arg5Cys) and c.289C>T; p.(Arg97Cys). Localized elevation of the anterior corneal curvature can occur in MCD in the absence of other features of keratoconus. The identification of a further two Czech probands with the compound allele c.[484C>G; 599T>G] supports the enrichment of this allele in the study population.

Characteristics of 244 patients with keratoconus seen in an optometric contact lens practice

BackgroundThe purpose of this study was to describe the characteristics of keratoconic patients seen in a specialised contact lens practice from a general population with a high prevalence of the disease.MethodsPatients attending a contact lens practice for management of keratoconus were asked to complete a questionnaire. Data were collected on demographic characteristics, general health, family history, eye rubbing, allergy, asthma, eczema, education level, history of keratoplasty and smoking.ResultsTwo hundred and forty‐four patients completed the questionnaire. There was a male bias (54.5 per cent). The majority of the patients (78.7 per cent) wore contact lenses, of whom 67.7 per cent wore hard, 13 per cent soft and 4.2 per cent scleral contact lenses. Some of the patients (21.3 per cent) had undergone corneal graft surgery. Eighteen per cent had an associated systemic disease, the most common of which was type 2 diabetes, although this disease was less prevalent, but not significantly, in the keratoconic sample than in the general population (p = 0.19). The prevalence of eye rubbing (65.6 per cent) was similar to other studies. Compared to the general population, asthma (13.2 per cent) was slightly, but not significantly, less prevalent (p = 0.17), eczema (6.6 per cent) was significantly less (p < 0.001) and allergy (34.4 per cent) was more prevalent (p < 0.001). A high proportion of patients reported a family history of the disease (27.9 per cent) and most were better educated than the general population.ConclusionThe results of this survey concur with those of other studies with regard to most known characteristics of keratoconus; however, the proportion of asthma and eczema tended to be less than in other surveys and may be linked to the environmental influence of a hot and sunny country. The high prevalence of positive family history of the disease in this cohort suggests a genetic influence.

PRK em olhos com topografia atípica e pentacam normal

OBJECTIVE: To evaluate the safety of PRK in patients with atypical corneal topography, but without features of keratoconus in Pentacam. METHODS: Medical records of patients who underwent PRK method that presented atypical corneal topography and Pentacam rates considered normal in the pre operative were analyzed. The sample consisted of nineteen eyes of ten patients. The considered criteria of corneal irregularity were: increased curvature greater than 47D with asymmetry less than 1,5D, 1,5D displacement above the apex and inferior-superior asymmetry greater [...]

Clinical features of 233 cases of keratoconus

To analyze clinical features of keratoconus. The case history of keratoconus patients who underwent penetrating keratoplasty, epikeratophakia or deep lamellar keratoplasty in our hospital during January 1993 to March 2002 was reviewed, and inquiry form was sent to those who without complete data. Patients were followed during January 2000 to March 2002. Two hundred and thirty three cases of keratoconus were enrolled in this study with 216 males and 17 females. Patient's family history, systemic complications, refractive status, progress of disease, eye axial length and anterior chamber depth were recorded. The clinical natural history of these patients followed the model of "myopia-astigmatism-poor spectacle correction-acute corneal hydrops or stromal scar". The presenting age of myopia ranged from 6 to 29 years, with a mean age of 13.8 years, 10.1% (22/219) of the patients were younger than 10 years, 67.1% (147/219) were between 11 and 15 years. The interval time between emerging myopia and poor spectacle correction (best corrected visual acuity less than 20/200) was ranged from 1 to 20 years, of which 85.2% (161/189) were shorter than 6 years. Twenty percent (47/233) of the patients had acute corneal hydrops in one eye at the age of 12 to 31 years, and 4.3% of them (2/47) resulted in corneal perforation. Thirty-four patients had corneal stromal scars 1 to 13 years after keratoconus developed, and 94.1% of them (32/34) were within 8 years. Topography examination demonstrated a tendency of the cone base position progress: first, paracentral-enlargement following dominant astigmatism axis, then, enlargement along smaller astigmatism axis, and finally, the cone base moving centrally. The eye axial length averaged at (25.9 +/- 1.4) mm, the depth of anterior chamber (AC) were (4.3 +/- 0.3) mm, 89.7% (279/311) eyes had an axial length longer than 24 mm. All cases had an asymmetry clinical progress course. Two cases had Down syndrome, 2 with intelligence defect. No family history was noted in this study. Keratoconus in Han nationality of Shandong Province has a relatively earlier age onset. These eyes tend to have a deeper AC with higher incidence of longer axial length.

Pseudo-kératocône et rosacée oculaire

Photokeratoscopy analysis of the anterior curve of the cornea can detect keratoconus, particularly in the early stages of the disease. Nevertheless, all irregular astigmatisms are not related to keratoconus. We report here several cases of patients presenting high asymmetric astigmatism with features of keratoconus, although the clinical examination suggests corneal disease related to rosacea.