Repeatability assessment of anterior segment measurements in myopic patients using an anterior segment OCT with placido corneal topography and agreement with a swept-source OCT.

BACKGROUND: The precision of anterior segment biometric measurements in eyes has become increasingly important in refractive surgery. The purpose of this study is to assess the repeatability of the automatic measurements provided by a new spectral-domain optical coherence tomograph (SD-OCT)/Placido topographer (MS-39, CSO) and its agreement with a swept-source OCT (SS-OCT) biometer (CASIA SS-1000, Tomey) in patients with myopia. METHODS: The right eye of 235 subjects was scanned 3 times with both devices. The evaluated parameters included central corneal radius of the steep meridian, central corneal radius of the flat meridian, mean central corneal radius, thinnest corneal thickness, central corneal thickness, anterior chamber depth, corneal volume and diameter. The intraobserver repeatability of the MS-39 measurements was calculated using intraclass correlation coefficient (ICC), within subject standard deviation, coefficient of repeatability, coefficient of variation and repeated-measures analysis of variance of the 3 repeated measurements. The agreement between the two devices was evaluated by 95% limits of agreement (LoA). RESULTS: The majority of the parameters acquired from MS-39 showed high repeatability. The repeatability of corneal diameter was slightly lower than the other measurements, although the ICC remained high. Agreement with the CASIA SS-1000 was good, indicated by the Bland-Altman plots with narrow 95% LoA values for all parameters assessed. CONCLUSIONS: The high repeatability of automatic measurements by the new device supports its clinical application in eyes with myopia, and the good agreement between the two devices indicates they could be used interchangeably for the parameters evaluated.

Bacterial Keratitis Following Small Incision Lenticule Extraction.

Purpose: To describe the development of bacterial keratitis after small incision lenticule extraction in 5 patients and to explore its appropriate therapies. Methods: We retrospectively summarized the clinical treatments of five patients with postoperative bacterial infection after small incision lenticule extraction, who were referred to our hospital from 2019 to 2021. Results: Five male patients had undergone bilateral SMILE in the local hospital due to myopia aged from 18 to 26 years. The onset of keratitis during 1-3 days postoperatively and four of them were severe infection (2 bilateral, 2 unilateral). In five cases, 1 patient (1 eye) who was infected mild keratitis after SMILE was treated with only topical antibiotics; the others who respond poorly to topical antibiotics require surgical treatment, which 1 patient (1 eye) infected necrotic mass of the corneal cap was scraped and irrigated with antibiotic, and 3 patients (5 eyes) were treated by converting the cap to flap, curetting the necrotic tissue and irrigating with the antibiotic solution. In all patients, the duration from onset to resolution was 1-5 weeks. The final uncorrected visual acuity was above 20/32. Conclusion: Owing to the upward popularity of refractive surgery, the incidence of keratitis after SMILE should not be ignored. Early diagnosis and timely treatment of post-SMILE keratitis are essential. For severe keratitis that fails to respond to topical antibiotics, the corneal cap should be opened as a flap.

[The investigation of microbial culturing of microkeratome blades and sponges used in laser in situ keratomileusis].

OBJECTIVE: The microbial culturing results were analysed from samples of the microkeratome blade and sponges in laser in situ keratomileusis (LASIK) procedures as for crossing the rational antibiotic eye drops for preventing infectious keratitis. METHOD: In this prospective study, 106 microkeratome blades and 212 sponges were cultured in routine LASIK procedure, at Excimer laser center in Henan Eye Institute During March to April 2009. Positive cultures were then sent for routine sensitivities and the results were analysed. RESULTS: 8 of the 106 blades were culturing positive, the positive rate was 7.55%. Each four positive cultures were in male and female patients. There was no statistical difference with gender (P = 1.000). 23 of the 212 sponges cultures were positive. The positive rate was 10.38%. All positive cultures grew Staphylococcus epidermidis. Twelve sponge positive cultures were in right eye and 11 were in left eye. There was no statistical difference between the right eye and left eye (P = 0.825). All of the 31 positive cultures were sensitive to gatifloxacin. The sensitivity of gatifloxacin, tobramycin, levofloxacin, ofloxacin, and ciprofloxacin were 100.00%, 96.77% (30/31), 93.55% (29/31), 90.32% (28/31) and 74.20% (23/31) respectively. All the patients have no infectious keratitis followed-up more then 6 monthes. CONCLUSION: There could be positive cultures from samples of the microkeratome blade and sponges in routine LASIK procedures but no patients with positive cultures developed postoperative infectious keratitis. The main positive bacteria was Staphylococcus epidermidis. They are sensitive to third and the fourth-generation fluoroquinolones and tobramycin antibiotics. Pre and post-operative supply of sensitive antibiotics can prevent post-operative infection.

[The clinical analysis of corneal interface fluid syndrome].

OBJECTIVE: To analysis the clinical characteristics of corneal interface fluid syndrome (IFS). METHODS: This is a retrospective study. During Jun. 2007 to Oct. 2011. Eight cases (12 eyes) of IFS were diagnosed at Henan Eye Institute. The history and complete ophthalmic examination that include Slit-lamp examination, Slit-lamp photography, IOP, anterior segment OCT (AS-OCT), confocal microscopic exams were recorded. RESULTS: In total 8 cases (12 eyes), 4 cases were bilateral, 4 cases were unilateral. Six patients were male and 2 were female. The age of the patients ranged from 19 to 35 years. Post-lasik steroid-induced elevated IOP was 4 eyes in 2 patients. Primary open angle glaucoma was 4 eyes in 2 patients. 1 patient (1 eye) was Posner-Shlossman syndrome, 1 patient (1 eye) was pigmented glaucoma, 1 patient (1 eye) was post-lasik traumatic iritis. 1 patient (1 eye) got IFS after repeated flap reposition because of epithelium ingrowth. Slit-lamp exam indicated edematous corneal, lamellar haze, interface fluids accumulation. AS-OCT showed obvious interface dark area. Confocal microscopy exam showed edematous corneal flap, more oval and large keratocytes' nuclei but no inflammatory cells. CONCLUSIONS: IFS is a rare but serious complication after LASIK. The main causes are high intraocular pressure and/or dysfunction of corneal endothelium. Careful exam by slit-lamp may help diagnosis, and further AS-OCT and/or in vivo confocal microscopy exam will confirm it.

[Mutation in the UBIAD1 gene of a Chinese family with Schnyder crystal corneal dystrophy].

OBJECTIVE: To investigate the genetic feature of Schnyder corneal dystrophy identified in a four-generation Chinese family. METHOD: Ophthalmologic examinations were performed in 3 affected members and 2 unaffected members of a family with Schnyder corneal dystrophy and controls. Genomic DNA was extracted from peripheral blood. The coding regions, 3'UTR and 5'UTR of UBIAD1 gene from all samples were screened by polymerase chain reaction (PCR) and direct DNA sequencing using the primers designed according to the sequence of UBIAD1, and comparatively analyzed with data from Genebank. RESULT: The family has 15 members over 4 generations with similar signs and symptoms among proband and affected members. All affected members of the family demonstrated central discoid crystalline deposition with arcus lipoide. Confocal microscopy examination showed multiple depositions of crystalline materials in anterior stroma. OCT showed the high reflective material localized within the anterior stroma. A missense mutation c.305A > G in 1 exon of UBIAD1 gene resulting in a substitution of Asparagine to Serine at codon 102 (p.Asn102Ser) was found in all affected members of the family who were clinically diagnosed as Schnyder corneal dystrophy while not in the unaffected members of the family and controls. CONCLUSION: The missense mutation c.305A > G(p.Asn102Ser) of UBIAD1 gene may cause the disease of the family. Gene screen can assist clinicians in making definitive diagnosis, presymptomatic diagnosis and prenatal diagnosis.

[Clinical observation of posterior polymorphous corneal dystrophy].

OBJECTIVE: To research the clinical features and in vivo confocal microscopic findings of posterior polymorphous corneal dystrophy (PPCD). METHODS: It was a retrospective consecutive case study. Ten patients with PPCD, attended at Optometry Department of Henan Eye Institute from March 2007 to August 2009, were analyzed. All the subjects were examined by slit-lamp, OrbscanII, specular microscopy, HRT3/RCM confocal microscopy. Mann-Whitney U test was used to analysis the data. RESULTS: The age of the patients ranged from 8 to 35 years. Seven eyes of the 4 patients have the vesicular lesions, five eyes of the 5 patients were band lesions and 1 patient had bilateral diffused opacities, this patient also had iridocorneal adhesions with associated papillary ectropion but without glaucoma. In total, 14 eyes of the 10 patients had PPCD. Two eyes had abnormal OrbscanII topography, it showed both anterior and posterior surface protrusion. Specular microscopy exam indicated large cells in size and reduced endothelium density. The mean size of the affected eye was 584 µm(2), the normal eye was 316 µm(2). The difference was statistically significant (U = 0.000, P = 0.002). The density of the endothelium was 1746 cells/mm(2) in affected eye and 3201 cells/mm(2) in normal eye. The difference was also statistically significant (U = 0.000, P = 0.002). In vivo confocal microscopy showed endothelial polymorphism. Occasional bright endothelial nuclei were seen. A variety of curvilinear and vesicular abnormalities were imaged including orange or finger like lesion, round or oval dark area with hyper reflectivity border. Some large lesions may lose endothelium with rough surface have a dike appearance. CONCLUSIONS: Careful exam by slit-lamp may help to diagnose PPCD and further specular microscopy and(or) in vivo confocal microscopy exam will confirm it. Some cases may have abnormal topography, or associated with high intraocular pressure.