Small incision lenticule extraction and femtosecond-assisted laser in situ keratomileusis in patients with deep corneal opacity:case series

AIM:To report the safety,efficacy,and accuracy of small-incision lenticule extraction(SMILE)or femtosecondassisted laser in situ keratomileusis(FS-LASIK)for the correction of myopia or myopic astigmatism in patients with deep corneal opacity denoted by anterior segment optical coherence tomography(AS-OCT).METHODS:Four patients with monocular corneal opacity(3 due to mechanical injury,1 due to a firecracker wound)were recruited and treated with refractive surgery(3 for SMILE,1 for FS-LASIK combined with limbal relaxing incision(LRI).Preoperative ocular manifestations,surgical details,postoperative visual outcomes,corneal opacity parameters,and corneal topography were analyzed.RESULTS:Preoperatively,spherical diopter ranged from-3.0 D to-4.75 D with cylinder ranging from-0.75 to-5.0 D,and corrected distance visual acuity(CDVA)ranging from 20/25 to 20/20.One eye’s corneal opacity was located in the central zone and three were in the mid-peripheral optical zone.Three patients underwent uneventful SMILE in both eyes,whilst one patient underwent FS-LASIK for high astigmatism in both eyes and LRI in the right eye.CDVA of the eye with corneal opacity ranged from 20/22to 20/20 one to six weeks postoperatively.Two patients achieved better CDVA and no patients lost Snellen lines.The postoperative diopter was within±0.75 D for all eyes.Significant edema existed above the corneal opacity in one eye and dissipated soon.No eccentric corneal topography or morphological anomaly of the corneal cap or flap was observed.CONCLUSION:The cases demonstrate that SMILE or FS-LASIK is safe and effective to treat myopic astigmatism combined with deep corneal opacity lesions after comprehensive preoperative evaluation and appropriate candidate selection.FS-LASIK combined with LRI is also sufficient for correcting high astigmatism due to corneal scarring.

Image Analysis on Corneal Opacity:A Novel Method to Estimate Postmortem Interval in Rabbits

Corneal opacity is one of the most commonly used parameters for estimating postmortem interval （PMI）. This paper proposes a new method to study the relationship between changes of corneal opacity and PMI by processing and analyzing cornea images. Corneal regions were extracted from images of rabbits＇ eyes and described by color-based and texture-based features, which could represent the changes of cornea at different PMI. A KNN classifier was used to reveal the association of image features and PMI. The result of the classification showed that the new method was reliable and effective.

Method Optimization and Application Extension of Bovine Corneal Opacity and Permeability Assay

This paper systematically summarizes the improvements in bovine corneal opacity and permeability assay(BCOP),an alternative method of eye irritation test,further explores the usage mode of combinatorial methods with BCOP at the core module,introduces the application of each single method and their combination in the assessment of pesticides,plant extracts,medical devices and medicines.By optimizing traditional methods,the alternative method is more scientific and individually applicable.

TGFBI gene mutation analysis in a Chinese pedigree of Avellino corneal dystrophy

AIM: To analyze phenotype and genotype of a Chinese pedigree with Avellino corneal dystrophy (ACD). METHODS: Complete ophthalmic EX aminations were performed on all the family members. Exons of TGFBI were amplified by polymerase chain reaction, sequenced, and compared with a reference database. RESULTS: A single heterozygous G>A(R124H) point mutation was identified in exon 4 of TGFBI in three affected members and two unaffected children who were offsprings of the affected members, but not in the other family members. CONCLUSION: Mutation R124H in TGFBI was identified in this pedigree and appeared to be the disease causing mutation. Atypical phenotype and low penetrance was observed in this pedigree..

Fourier-domain optical coherence tomography-guided phototherapeutic keratectomy for the treatment of anterior corneal scarring

AIM:To evaluate the safety,visual and anatomic outcomes of fourier-domain optical coherence tomography(FD-OCT)-guided excimer laser phototherapeutic keratectomy(PTK)combined with photorefractive keratectomy(PRK)surgery in treating anterior corneal scarring.METHODS:Clinical data of 23 eyes of 21 patients with anterior corneal scarring underwent FD-OCT-guided PTK and PRK from Dec.2014 to Jul.2016 were reviewed.Patients were assessed for preoperative and postoperative uncorrected visual acuity(UCVA),best spectacle-corrected visual acuity(BSCVA),contrast sensitivity(CS),FD-OCT,corneal topography and colour figures of anterior segments.RESULTS:The preoperative corneal pathologic conditions included viral keratitis(7 patients,7 eyes),band keratopathy(2 patients,4 eyes),corneal dystrophy(4 patients,4 eyes),traumatic corneal disease(2 patients,2 eyes)and corneal chemical injury(6 patients,6 eyes).Mean follow-up time was 10.65(range,3-19)mo.UCVA(in IogMAR)improved from a mean of 0.79(95%Cl,0.28­1.29)preoperatively to a mean of 0.45(95%Cl,0.29-0.62)postoperatively(P=0.021).BSCVA(in IogMAR)improved from 0.57(95%Cl,0.27-0.88)preoperatively to a mean of 0.28(95%Cl,0.15-0.41)postoperatively(P=0.001).Corneal topographic indices postoperatively showed significant improvement in corneal cylinder(P=0.009),the surface regularity index(P=0.007)and surface asymmetry index(P=0.00).Postoperative spherical equivalent averaged-0.53 diopters(-1.49 to 0.42).No complications were associated with the treatment.CONCLUSION:FD-OCT-guided PTK combined with PRK is safe and effective for the treatment of anterior corneal scarring by eliminating or reducing corneal opacities.

A new multiple noncontinuous puncture(pointage)technique for corneal tattooing

AIMTo assess the safety and cosmetic efficacy of a new multiple noncontinuous transepithelial puncture technique for tattooing a decompensated cornea.METHODSIt was a non-comparative clinical case series study. The study examines 33 eyes in 33 patients with total corneal opacity due to corneal decompensation, which developed following intraocular surgery. Corneal tattooing was performed using the multiple noncontinuous transepithelial puncture technique (i.e. pointage). The safety of this new surgical strategy was assessed by occurrence of adverse events for the follow-up period. The cosmetic efficacy was determined by the patient's cosmetic satisfaction and independent observer's opinion about patient appearance.RESULTSSeven women and 26 men were included in the study. The mean age was 46.4±17.5y (range: 7-67). In total, 30 of 33 patients (91%) reported cosmetic satisfaction within the follow-up period. Only 3 patients (9%) required additional tattooing due to cosmetic unsatisfaction. Cosmetic outcomes were analyzed and classified as excellent or good in 13 (39%) and 17 (52%) patients, respectively. No serious adverse events developed, except delayed epithelial healing in 3 cases.CONCLUSIONThe cosmetic outcomes of the multiple noncontinuous transepithelial puncture technique for corneal tattooing were good. The safety of this method is higher than conventional procedures. This new procedure also provides improved cost-effectiveness and safety over current corneal tattooing techniques.

A recognition survey of granular corneal dystrophy type 2 genetic detection in China

AIM:To evaluate the feasibility of promoting genetic detection for granular corneal dystrophy type 2(GCD2)by a questionnaire conducted among citizens in five cities in China.METHODS:The data were collected by questionnaire,and analyzed by Chi-square test and one-tailed t test in IBM SPSS statistics.RESULTS:Based on the survey data on the awareness of GCD2 genetic detection in this study and the positive predictive analysis report of the citizens in five cities in China,the vast majority(84.2%)of respondents had never heard of it and did not know that GCD2 patients have been prohibited from performing excimer surgery that can deteriorate GCD2 patients’condition even leading to blindness.Though 3.4%of patients understood GCD2 very much,they have no idea that GCD2 could not be 100%accuracy diagnosed by the conventional inspection methods.CONCLUSION:It is feasible and necessary to use GCD2 genetic detection as an excimer preoperative examination project.In order to promote the development of detection project,a few improvements should be carried out in terms of the promoting efforts,costs,and research progress.

Penetrating keratoplasty in children under 3 years old with congenital corneal opacities

AIM:To evaluate the graft rejection and visual outcomes after penetrating keratoplasty(PK)in the presence of various congenital corneal opacities in children.METHODS:In this retrospective cohort study,children who underwent PK were then followed for 5 y.The patient’s medical records were collected from June 2014 until June 2019 and analyzed in December 2019.All patients were children under three years old with congenital corneal opacities with or without microcornea who came to a pediatric ophthalmologist and underwent PK in Jakarta Eye Center(JEC).Beforehand,all children have participated in a thorough evaluation for PK.In the case of severe microcornea was not advised to undergo surgery.The visual outcomes and graft survival rate were described in percentages.The graft survival plot was presented with Kaplan-Meier,while the visual acuity was analyzed using the Wilcoxon signed ranks test.RESULTS:Sixteen eyes from eleven patients(seven girls and four boys)underwent PK.The graft survival rate of the first 6,12,and 18 mo later of keratoplasty was 100%,83.3%,and 66.7%,respectively.The overall mean survival time is 22 mo(standard error 2.419),and no significant difference between the patients underwent PK before and after 36 mo of their age(P=0.52).The graft failure was 50%,and postsurgery complications included cataract 43.7%,band keratopathy 12.5%,and scleromalasia 6.25%.Wilcoxon test analysis of visual acuity post keratoplasty was not statistically significant(P=0.34),while overall showed 44%improvements of visual outcome for 5 y of follow-up.With a good survival at one year up to 22 mo(83.3%),the visual acuity could be achieved(63%),and showed improvements(44%)during follow-up.CONCLUSION:The complications are frequent for pediatric PK.Thus,corneal surgery on infants requires careful case selection,adequate pre-operative evaluation,skilled surgery(optical correction),very close cooperation family–physician,intensive post-operation care,and amblyopia management in the future.

Three-year follow-up in advanced pediatric keratoconus:thin corneas may not have pachymetry properly assessed after crosslinking

AIM:To analyze the crosslinking(CXL)effects in pediatric keratoconus,and to identify the patients’corneal characteristics whose pachymetry could not be adequately evaluated by Scheimpflug method after procedure.METHODS:Consecutive pediatric patients with progressive keratoconus underwent CXL were included.Best-corrected visual acuity(BCVA)and spheric equivalent(SE)were measured before and after CXL.After CXL,groups 1 and 2 were divided based on the posterior surface Pentacam quality specifications(QS):"OK"(Group 1)and"not OK"(Group 2).The mean(RmF and RmB)and minimum(RminF and RminB)radius of curvatures of the anterior and posterior corneal surfaces,and the thinnest pachymetry(Pmin)were measured preoperatively at 3,6,12,24,and 36 mo.Haze was annotated.RESULTS:Twenty-six patients(14 men,mean age 14±1.8 y)and median Kmax of 59.9 D initially and 61.4 D preoperatively were treated.BCVA was not different before and 24 mo after CXL.Group 2 statistically differed to group 1 in that SE was more myopic before and with no difference 24 mo after CXL;RmF and RmB were steeper and Pmin was thinner pre-surgically.Group 2,in which pachymetric changes could not be adequately evaluated after surgery,presented with significant RmF flattening,a shift to hyperopia,and more haze after CXL.CONCLUSION:Patients whose pachymetry could not be adequately evaluated after CXL had steeper and thinner corneas before surgery.The predictive factors for impaired QS after CXL are RmF,RmB,and Pmin.In advanced keratoconus,alternative methods to analyze pachymetry and the posterior surface should be considered.

Computerized Detection of Limbal Stem Cell Deficiency from Digital Cornea Images

Limbal Stem Cell Deficiency(LSCD)is an eye disease that can cause corneal opacity and vascularization.In its advanced stage it can lead to a degree of visual impairment.It involves the changing in the semispherical shape of the cornea to a drooping shape to downwards direction.LSCD is hard to be diagnosed at early stages.The color and texture of the cornea surface can provide significant information about the cornea affected by LSCD.Parameters such as shape and texture are very crucial to differentiate normal from LSCD cornea.Although several medical approaches exist,most of them requires complicated procedure and medical devices.Therefore,in this paper,we pursued the development of a LSCD detection technique(LDT)utilizing image processing methods.Early diagnosis of LSCD is very crucial for physicians to arrange for effective treatment.In the proposed technique,we developed a method for LSCD detection utilizing frontal eye images.A dataset of 280 eye images of frontal and lateral LSCD and normal patients were used in this research.First,the cornea region of both frontal and lateral images is segmented,and the geometric features are extracted through the automated active contour model and the spline curve.While the texture features are extracted using the feature selection algorithm.The experimental results exhibited that the combined features of the geometric and texture will exhibit accuracy of 95.95%,sensitivity of 97.91% and specificity of 94.05% with the random forest classifier of n=40.As a result,this research developed a Limbal stem cell deficiency detection system utilizing features’fusion using image processing techniques for frontal and lateral digital images of the eyes.