Keratoconus is a progressive blinding eye disease that characterized by corneal thinning and protrusion, which accompanied with irregular astigmatism and impaired visual acuity.The irregular astigmatism of early keratoconus can be corrected by spectacles. For the irregular astigmatism of moderate to severe keratoconus, spectacles are no longer suitable, and contact lenses are the best choice for patients to restore vision. There are various types of contact lenses, making the selection very difficult. In addition, trying on lenses for a long time will increase the discomfort and overall feeling of patients, and greatly increase the workload of doctors. Thus, the article aims to summarize and discuss the classification of contact lenses, the application of contact lenses in different types of keratoconus, the complications of contact lens, and the current status and prospect of contact lenses, with a view to understanding the management and clinical application of contact lenses in keratoconus patients and to further improving the application value of contact lenses in keratoconus.

Keratoconus is a blinding corneal disease characterized by central or paracentral corneal thinning and conical ectasia, and usually happens in adolescence. Currently, the etiology of keratoconus is unclear. Multiple studies have identified an association between genetics, eye rubbing, allergic diseases, ultraviolet exposure and keratoconus. Recently, several studies identified that sex hormones also played important roles in the pathogenesis of keratoconus. The disturbance of sex hormones may increase the risk of occurrence and progress of keratoconus. This review aims to summarize the pathophysiological effects of sex hormones on the cornea, clarify the effects of sex hormones on keratoconus and its related inflammatory or immune mechanisms, and explore the role of sex hormones in the early diagnosis and treatment of keratoconus, providing reference and help for clinical work.

Objective:To investigate the repeatability of corneal topographic parameters with the Pentacam HR in patients with keratoconus of different severity.Methods:A diagnostic test study was performed.A total of 120 eyes from 98 patients with subclinical keratoconus or keratoconus were enrolled at Henan Eye Hospital from January 2019 to March 2022.The patients were divided into subclinical keratoconus group, mild keratoconus group, moderate keratoconus group and severe keratoconus group, with 30 eyes in each group.An additional 30 eyes of 30 subjects undergoing refractive surgery were selected as a control group.Three consecutive Pentacam HR measurements were performed by the same clinician.The recordings included a total of 53 parameters in anterior corneal surface, posterior corneal surface, thickness, composite index, and corneal densitometry.The within-subject standard deviation (Sw), repeatability limit ( r) and tolerance index (TI) were calculated to evaluate the repeatability of the parameters between different groups.This study adhered to the Declaration of Helsinki and was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2019[5]).All subjects were informed of the purpose and significance of the study and signed an informed consent form before enrollment. Results:Compared with the control group, the TI of the subclinical, mild, moderate and severe keratoconus groups were 54.71%(29/53), 66.04%(35/53), 90.57%(48/53) and 94.34%(50/53), respectively, higher than 0.31.The steep keratometry (Ks), the maximum keratometry (Kmax) of the anterior corneal surface, the anterior corneal radius of curvature, the flat keratometry (Kf) of the posterior corneal surface, the posterior corneal radius of curvature (PRC), the thinnest corneal thickness (TCT), the average densitometry for the anterior 120 μm in the 0-2 mm area (A.0-2 mm), average densitometry for the anterior 120 μm in the 2-6 mm area (A.2-6 mm), average densitometry for the central tissue in the 0-2 mm area (C.2-6 mm), average densitometry for the total cornea in the 0-2 mm area (T.0-2 mm) and average densitometry for the total cornea in the 2-6 mm area (T.2-6 mm) showed good repeatability in the subclinical and mild keratoconus groups (TI<0.31).Kmax Zonal Mean 3 mm, posterior corneal surface mean keratometry, central keratoconus index showed good repeatability in subclinical, mild and moderate keratoconus groups.Kmax Zonal Mean 4 mm and Kmax Zonal Mean 5 mm showed good repeatability in all groups (TI<0.31).Conclusions:For patients with subclinical and mild keratoconus, Kf of the posterior corneal surface, PRC and TCT are recommended to monitor disease progression.To monitor the condition of patients with moderate and severe keratoconus, we may focus on the detection of Kmax Zonal Mean 4 mm and Kmax Zonal Mean 5 mm.

Objective:To investigate the clinical characteristics of patients with keratoconus, and to explore the factors influencing keratoconus severity.Methods:A cross-sectional study was performed.A total of 908 patients (1 476 eyes) with primary keratoconus were enrolled in Henan Eye Hospital from January 2019 to December 2021.The medical history data of patients were collected by face-to-face questionnaire survey.Refractive parameters were measured by subjective optometry.Intraocular pressure (IOP) was measured by a non-contact tonometer, and corrected IOP was calculated by Dresden formula.Corneal topography parameters was obtained using Pentacam HR.The subgroup analysis of clinical characteristics of all patients was performed by age (<21 years, 21~<31 years, ≥31 years) and gender.Disease severity was graded based on steep keratometry (Ks), namely mild (Ks<48 D), moderate (48 D≤Ks<55 D) and severe (Ks≥55 D). The influencing factors of disease severity in keratoconus were analyzed by ordered Logistic regression.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2019[5]). All subjects or guardians were informed of the purpose and significance of the study and written informed consent was obtained.Results:Of the 908 patients, 622 were with bilateral keratoconus and 286 were with unilateral keratoconus.The median age of onset was 20(17, 26) years, and the median age of diagnosis was 21(18, 27) years.The ratio of males to females was 3.05∶1.There were 9.80%(89/908) of the patients having a history of allergy, 25.55%(232/908) having a history of other systemic diseases, and 1.98%(18/908) having a family history of keratoconus.Of the 1 476 affected eyes, 27.57%(407/1 476) were diagnosed as severe keratoconus, and 61.94%(568/917) had a history of eye rubbing.The medians of sphericity, cylindricity, IOP, corrected IOP, Ks, thinnest corneal thickness (TCT), anterior corneal surface elevation (AE) and posterior corneal surface elevation (PE) were -4.00(-7.00, -1.75)D, -3.50(-6.00, -1.50)D, 12.00(10.30, 13.80)mmHg, 15.40(13.60, 17.00)mmHg, 49.85(46.40, 54.90)D, 460.00(425.00, 490.00)μm, 21.00(13.00, 34.75)μm, 51.00(33.00, 75.00)μm, respectively.The spherical refraction, IOP and corrected IOP were lower and the cylindrical refraction was higher in patients at age <21 years than in patients at age 21~<31 years, and the TCT of patients at age <21 years was higher than that at age ≥31 years, and the differences were statistically significant (all at P<0.05). Compared with female patients, male patients had younger onset age, lower spherical refraction, IOP and corrected IOP, as well as higher cylindrical refraction, AE and PE, showing statistically significant differences (all at P<0.05). The spherical refraction and IOP of male patients were lower than those of female patients at age <21 years, and the cylindrical refraction was higher in males than in females among the patients at age 21~<31 years, and the differences were statistically significant (both at P<0.05). Among the patients with onset age <21 years and diagnosis age <21 years, the ratio of males to females in patients with severe keratoconus was higher than those with mild and moderate disease, and the difference was statistically significant (both at P<0.05). Older age of onset was a protective factor for disease severity in keratoconus (odds ratio=0.981, 95% confidence interval: 0.963~0.999). Conclusions:The younger the onset age of keratoconus patients, the more severe the disease.Among the patients with severe keratoconus, there were more male patients, and males have a younger onset age and severer conditions.It is suggested that early screening of keratoconus in children and adolescents should be strengthened in clinical work, and more active prevention and treatment measures should be taken for younger patients, especially males.

Objective:To compare the fitting effect between rig gas-permeable contact lens (RGPCL) and scleral lenses (SLs) in moderate and severe keratoconus eyes.Methods:A cross-sectional study was performed.Fifty-two eyes of 42 keratoconus patients were recruited in Henan Eye Hospital from September 2022 to September 2023.Based on steep keratometry (Ks) value, patients were divided into moderate stage (48 D≤Ks<55 D, 28 eyes) and severe stage (Ks≥55 D, 24 eyes). RGPCL and SLs were fitted normatively in all eyes.Fluorescein staining and anterior segment optical coherence tomography were performed under a slit lamp.The distance between the central and lateral centers of the lenses and the cornea, the centering of the lenses, the mobility of the lenses and the peripheral fit of the lenses were observed.Best corrected visual acuity (BCVA) converted to logarithmic minimum angle of resolution, comfort score, wetness score and clarity score were recorded.Differences in the above parameters of each patient between RGPCL and SLs wear were compared.The improvement of the above parameters after RGPCL and SLs wear was compared in moderate and severe patients.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2019[5]-04). Written informed consent was obtained from each patient before any medical examination.Results:After RGPCL wear, the mean BCVA, comfort, wetness, and clarity score were 0.19(0.10, 0.30), 5.5(3.0, 7.0) points, 7.0(5.0, 8.0) points and 7.0(4.0, 8.0) points, respectively.After SLs wear, the mean BCVA, comfort score, wetness score and clarity score were 0.10(0.00, 0.10), 8.0(8.0, 9.0) points, 8.0(8.0, 9.0) points and 8.0(6.0, 9.0) points, respectively.Compared with RGPCL wear, the BCVA, comfort score, wetness score and clarity score of SLs were significantly improved ( Z=-5.887, -6.064, -5.705, -5.516; all at P<0.001). There was a moderate positive correlation between BCVA and Kmax after SLs wearing ( rs=0.519, P<0.001), and had a moderate negative correlation with TCT ( rs=-0.535, P<0.001). There was a moderate positive correlation between the clarity score of the SLs and TCT ( rs=0.303, P=0.029). In the moderate and severe subgroup analysis, BCVA, comfort score, wetness score and clarity score were significantly improved after SLs wear compared to RGPCL (all at P<0.05). In addition, the clarity score was significantly improved in severe keratoconus compared to moderate keratoconus ( Z=-3.100, P=0.002). Conclusions:In patients with moderate to severe keratoconus, RGPCL can improve BCVA to a limited extent.SLs can significantly improve patients' comfort, wetness and visual clarity while improving their BCVA.

Keratoconus is a progressive and bilateral corneal disease with the characteristics of the protrusion of the dilated and central thinning cornea.Keratoconus often causes myopia and irregular astigmatism, and corneal edema and scarring in the late stage, leads to significant vision loss, and brings patients psychological pressure and economic burden.Eye rubbing is an important risk factor of keratoconus.Many studies suggest that eye rubbing is related to the occurrence and development of keratoconus.Different frequency and intensity of eye rubbing have different effects on the cornea.In susceptible population, eye rubbing causes severer damage to the cornea and more serious consequences.Eye rubbing damages the cornea by direct mechanical action, raising corneal temperature and intraocular pressure and releasing inflammatory factors resulting in cell apoptosis.Avoiding eye rubbing is of great significance in delaying the development of keratoconus.Reducing the rubbing time and frequency of patients with keratoconus by treating the primary disease causing eye rubbing and distracting them can reduce the occurrence and slow down the progression of keratoconus, and the life quality of patients can be improved.In this review, the role of eye rubbing in the etiology of keratoconus was elucidated to provide reference for the treatment and prevention of keratoconus.

Corneal densitometry is a biological property of corneal tissue, which is related to the transparency of cornea, and can be used to describe the degree of corneal transparency.At present, corneal densitometry has been used in the auxiliary diagnosis and severity evaluation of corneal diseases, as well as in the evaluation of the surgical outcome and the postoperative follow-up, even some systemic diseases affecting the cornea.The measurement of corneal densitometry is an objective, non-invasive and repeatable method to evaluate corneal transparency, which has important reference values for the monitoring of corneal and systemic health.In this article, the application of corneal densitometry in clinical practices was reviewed.

Keratoconus is a corneal ectasia disease characterized by conical protrusion, progressive corneal thinning and irregular astigmatism.The etiology of keratoconus remains unclear now.Multiple factors contribute to the disease.A large number of studies have shown that the occurrence of keratoconus is closely related to heredity, and there exists obvious genetic heterogeneity.The incidence of keratoconus in patients with allergic diseases and frequent eye rubbing is high.Ultraviolet irradiation can damage the ocular surface and induce keratoconus subsequently.Keratectasia is a serious complication after refractive surgery.In this article, the risk factors including genetic susceptibility, eye rubbing, allergic diseases, ultraviolet irradiation, refractive surgery that related to keratoconus are reviewed.

Objective    To analyze the diagnosis and treatment of patients with ventricular septal defect complicated with infective endocarditis. Methods    We retrospectively analyzed the clinical data of 40 patients with ventricular septal defect complicated with infective endocarditis in our hospital from 2001 to 2016. There were 25 males and 15 females, aged 20-62 (39.92±11.16) years. They were divided into two groups according to the duration from admission to surgery: a group A (an early operation group whose surgery was performed within 7 days after admission) and a group B (a conventional treatment group with the duration from admission to surgery>7 days). Among them, there were 27 patients in the group A including 15 males and 12 females with an average age of 39.56±11.80 years, and 13 patients in the group B including 10 males and 3 females with an average age of 40.69±10.13 years. All patients were examined by echocardiogram and blood bacterial culture to investigate their etiology, echocardiogram results and treatment status. And the clinical data of the two groups were compared. Results    Two patients died before operation in the group B, one died of heart failure, and one cerebral infarction. No reoperation during hospitalization, cerebral infarction, thromboembolism or other complications occurred. The ventilation time in the group A was significantly shorter than that in the group B (18.00±14.85 h vs. 31.00±29.57 h, P=0.015). There was no statistical difference in the extracorporeal circulation time, myocardial block time, or postoperative hospital stay between the two groups (P>0.05). After discharge, the patients continued antibiotic therapy for 3-6 weeks. Patients were followed up for 12-127 (75.74±6.01) months, 1 died of malignant tumors in the group A, 1 developed atrial fibrillation and 1 developed cardiac insufficiency in the group B, and the rest of patients did not complain of obvious discomfort. There was no residual shunt, recurrence of infective endocarditis, reoperation, postoperative stroke or thromboembolism. Conclusion    Preoperative echocardio-graphy and blood bacteriological culture are helpful for the diagnosis and treatment of patients with ventricular septal defect complicated with infective endocarditis. Early surgery is safe and effective for these patients, and can improve the long-term survival rate.

Objective To study the sensitivity and specificity of parameter Corvis biomechanical index (CBI)— a new biomechanical index of Corvis ST in the diagnosis of keratoconus and evaluate the role of CBI in the diagnosis of keratoconus and the change of biomechanic.Methods A diagnostic trial study was adopted,and 66 eyes from 49 keratoconic patients (keratoconus group) and 91 right eyes from 91 myopic patients (control group) from April in 2018 to August in 2018 in Henan Eye Hospital were enrolled.Pentacam and Corvis ST examinations were performed by the same operator after the basic eye examinations.Using the evaluation of diagnostic test,consistency test,and receiver operating characteristic (ROC) curve analysis,gain the outcome of the sensitivity,specificity,consistency,Youden index,and area under the ROC curve of the parameter CBI.This study protocol was approved by Ethic Committee of Henan Eye Hospital and followed the Declaration of Helsinki.Written informed consent was obtained from each patient prior to any medical examination.Results Sixty eyes were diagnosed as keratoconus by the parameter CBI of Corvis ST.Evaluation of diagnosis test:the sensitivity was 97.0％,and the specificity was 97.8％;consistency check:Kappa =0.948,P＜0.05.ROC curve analysis:the sensitivity was 98.5％,the specificity was 96.8％,Youden index was 96.3％,P＜0.000 1 and AUC was 0.996.Conclusions CBI can separate healthy eyes from keratoconic eyes with highly sensitivity and specificity,which was highly consistency with results of Rabinowitz keratoconus diagnostic criteria.CBI could be used as a new biomechanical indicator for the diagnosis of keratoconus.