Assessment of iris volume in glaucoma patients with type 2 diabetes mellitus by AS-OCT

AIM:To examine the change of iris volume measured by CASIA2 anterior segment optical coherence tomography(ASOCT)in glaucoma patients with or without type 2 diabetes mellitus(T2DM)and explore if there is a correlation between hemoglobin A1c(HbA1c)level and iris volume.METHODS:In a cross-sectional study,72 patients(115 eyes)were divided into two groups:primary open angle glaucoma(POAG)group(55 eyes)and primary angle-closure glaucoma(PACG)group(60 eyes).Patients in each group were separately classified into patients with or without T2DM.Iris volume and glycosylated HbA1c level were measured and analyzed.RESULTS:In the PACG group,diabetic patients'iris volume was significantly lower than those of non-diabetics(P=0.02),and there was a significant correlation between iris volume and HbA1c level in the PACG group(r=-0.26,P=0.04).However,diabetic POAG patients'iris volume was noticeably higher than those of non-diabetics(P=0.01),and there was a significant correlation between HbA1c level and iris volume(r=0.32,P=0.02).CONCLUSION:Diabetes mellitus impact iris volume size,as seen by increased iris volume in the POAG group and decreased iris volume in the PACG group.In addition,iris volume is significantly correlated with HbA1c level in glaucoma patients.These findings imply that T2DM may compromise iris ultrastructure in glaucoma patients.

Associations of lens thickness and axial length with outcomes of laser peripheral iridotomy

AIM:To investigate the association of axial length(AL),lens thickness(LT),and lens vault(LV)with postoperative anterior chamber angle metrics after laser peripheral iridotomy(LPI).METHODS:Prospective observational study of 69 patients(97 eyes)were diagnosed as primary angle-closure suspect(PACS),primary angle closure(PAC)or primary angle-closure glaucoma(PACG).AL,LT,anterior central chamber depth(ACD),angle opening distance(AOD),trabecular iris angle(TIA),and angle recess area(ARA)were measured before and 1 wk after LPI.The association between AL,LT,LV with ACD,AOD,TIA,ARA were analyzed by comparing the differences between preoperative and postoperative measurements for anterior segment biometric parameters.RESULTS:ACD,AOD,TIA,and ARA were significantly increased after LPI(all P<0.05).Greater LT was significantly associated with greater postoperative increases in ACD,AOD,TIA,and ARA(all P<0.05).AL was not significantly associated with changes of anterior segment biometric parameters.Greater LV was significantly associated with greater postoperative increases in ACD,AOD,and TIA(all P<0.05),but was not significantly associated with changes of ARA.CONCLUSION:Greater baseline LT and LV measurements are associated with greater increases in anterior segment biometric parameters after laser peripheral iridotomy.AL are not associated with the change of anterior segment biometric parameters.

Clinical application of a shape-preserving rapid corneal donor dehydrater

AIM:To describe the design and clinical application of a corneal donor dehydrator which can quickly dehydrate corneas and keep its original shape.METHODS:The corneal donor material is placed on stainless steel beads with different diameters in the dehydrating box to make the cornea the same shape as the steel ball.Then,the cornea is placed inside the dehydrater for rapid dehydrating using the internal cleaning and ventilation system.Totally 83 eyes underwent deep anterior lamellar keratoplasty(DALK)using corneal donor tissue preserved with corneal dehydrater,and 60 patients(60 eyes)received DALK by the same surgeon using corneal donor tissue preserved with glycerol were included in the control group.The best corrected visual acuity(BCVA),the thickness and transparency of the corneal buttons were recorded.RESULTS:After the completion of dehydrating,all the donor corneas maintained a normal shape without any shrinkage or distortion,and the average intraoperative rehydration time was 43.3±12.1 s during operation.The mean BCVA of the dehydrater group was 0.30±0.18 at 1 wk and 0.32±0.16 at 1 mo,which were statistically better than that of the control group(P<0.001).The score of corneal buttons transparency were lower than that of the control group with statistical difference(P<0.001).The thickness of corneal buttons at 1 wk and at 1 mo in the dehydrater group was significantly better than that of the control group respectively(P<0.001).One week after operation,no corneal button turbidity or edema was observed in both groups.CONCLUSION:The dehydrater can quickly dehydrate the corneal material in a clean and airtight environment and maintain the original shape of the corneal donor during the dehydrating process.This dehydrater is recommended for long-term high-quality preservation in areas where corneal materials cannot be used within a reasonable time period.

Comparison of efficacy of two different silicone hydrogel bandage contact lenses after T-PRK

AIM:To compare the efficacy between two different silicone hydrogel bandage contact lenses after transepithelial photorefractive keratectomy(T-PRK).METHODS:In this randomized controlled trial,a total of 89 patients(178 eyes) who underwent T-PRK at the Qingdao Eye Hospital from October to December 2019 were selected.One random eye wore a Senofilcon A bandage contact lens after surgery,and the other eye a Balafilcon A bandage contact lens.Pain scores,uncorrected visual acuity(UCVA),spherical equivalent(SE),corneal epithelial healing status,epithelial thickness,bandage lenses deposits,lenses movement,and ocular surface conditions were measured and compared.RESULTS:There were no differences between the two groups in UCVA,SE,corneal epithelial healing status,corneal epithelial thickness,tear river heights and tear film rupture time at each follow-up visit.However,postoperative pain scores in the Senofilcon A group were significantly lower than those of the Balafilcon A group(F_(intergroups)=67.833,P<0.001;F_(time)=383.773,P<0.001;F_(interaction)=57.344,P<0.001).The duration of pain in eyes in the Senofilcon A group was shorter than that of the Balafilcon A group(t=-3.326,P=0.001).The surface deposition scores and movement scores of Senofilcon A bandage lenses on the first and fourth days after surgery were lower than those of Balafilcon A bandage lenses(Z=-5.385,-6.782,P<0.001;Z=-8.336,-8.906,P<0.001).CONCLUSION:Both Senofilcon A and Balafilcon A bandage lenses have good efficacy after T-PRK.Senofilcon A lenses are associated with less pain and more comfort compared to Balafilcon A.

Single-cell RNA sequencing in cornea research:Insights into limbal stem cells and their niche regulation

The corneal epithelium is composed of stratified squamous epithelial cells on the outer surface of the eye,which acts as a protective barrier and is critical for clear and stable vision.Its continuous renewal or wound healing depends on the proliferation and differentiation of limbal stem cells(LSCs),a cell population that resides at the limbus in a highly regulated niche.Dysfunction of LSCs or their niche can cause limbal stem cell deficiency,a disease that is manifested by failed epithelial wound healing or even blindness.Nevertheless,compared to stem cells in other tissues,little is known about the LSCs and their niche.With the advent of single-cell RNA sequencing,our understanding of LSC characteristics and their microenvironment has grown considerably.In this review,we summarized the current findings from single-cell studies in the field of cornea research and focused on important advancements driven by this technology,including the heterogeneity of the LSC population,novel LSC markers and regulation of the LSC niche,which will provide a reference for clinical issues such as corneal epithelial wound healing,ocular surface reconstruction and interventions for related diseases.

Should ocular Demodex be checked and treated in refractory keratitis patients without blepharitis?

AIM:To evaluate the correlation between Demodex infestation and keratitis,and to assess demodicosis using a simple approach.METHODS:A modified slit lamp illumination(at 40×magnification)was used to observe Demodex tails in 40patients with refractory keratitis and 80 healthy controls.Bacterial smear and culture of the conjunctival sac and corneal lesion were performed to identify the pathogen.Tea tree oil ointment(TTOO)was added as a Demodex killing agent for lid scrubs to the treatment when Demodex infestation was confirmed.RESULTS:Demodex tails were found in all patients compared to 42/80 of the controls(P<0.01).Seventeen patients presented blepharitis,while 23 were free of scales and inflammation at the lid margin.The demodicosis was mild,moderate,and severe in 8,19,and 13 patients,respectively,compared to mild in 42 controls(P<0.01).The keratitis was mild,moderate,and severe in 13,19,and 8patients,respectively.The severity of Demodex infestation was not correlated to the severity of keratitis(P=0.126).The growth of Staphylococcus was revealed in nine patients who did not react to antibiotic eye drops prior to the TTOO treatment.Patients’signs and symptoms got resolved after the lid scrub with TTOO.CONCLUSION:Ocular Demodex needs to be checked and treated in refractory keratitis patients with or without blepharitis.A slit-lamp illumination under high magnification favors the judgment of the severity of Demodex infestation.

The role of corneal endothelium in macular corneal dystrophy development and recurrence

Macular corneal dystrophy(MCD)is a progressive,bilateral stromal dystrophic disease that arises from mutations in carbohydrate sulfotransferase 6(CHST6).Corneal transplantation is the ultimate therapeutic solution for MCD patients.Unfortunately,postoperative recurrence remains a significant challenge.We conducted a retrospective review of a clinical cohort comprising 102 MCD patients with 124 eyes that underwent either penetrating keratoplasty(PKP)or deep anterior lamellar keratoplasty(DALK).Our results revealed that the recurrence rate was nearly three times higher in the DALK group(39.13%,9/23 eyes)compared with the PKP group(10.89%,11/101 eyes),suggesting that surgical replacement of the corneal endothelium for treating MCD is advisable to prevent postoperative recurrence.Our experimental data confirmed the robust m RNA and protein expression of CHST6 in human corneal endothelium and the rodent homolog CHST5 in mouse endothelium.Selective knockdown of wild-type Chst5 in mouse corneal endothelium(AC^(siChst5)),but not in the corneal stroma,induced experimental MCD with similar extracellular matrix synthesis impairments and corneal thinning as observed in MCD patients.Mice carrying Chst5 point mutation also recapitulated clinical phenotypes of MCD,along with corneal endothelial abnormalities.Intracameral injection of wild-type Chst5 rescued the corneal impairments in AC^(siChst5)mice and retarded the disease progression in Chst5 mutant mice.Overall,our study provides new mechanistic insights and therapeutic approaches for MCD treatment by highlighting the role of corneal endothelium in MCD development.

Increased cGAS/STING signaling components in patients with Mooren's ulcer

AIM:To explore the expression of cGAS/STING signaling components in Mooren’s ulcer(MU).METHODS:Samples were obtained from ten MU patients,and eight residual corneal-scleral rings of healthy donor corneas for controls.Human corneal epithelial cells(HCECs)were used to evaluate the effect of cGAS/STING signaling pathway.Immunohistochemistr y(IHC)and Western blot were used to examine the expression of cGAS,STING,and phosphorylated interferon regulatory factor 3(p-IRF3)in MU tissues.The expression of interferon-β(IFN-β)and interferon-stimulated genes(ISGs)was quantified by real-time polymerase chain reaction(PCR)and enzymelinked immunosorbent assay(ELISA).RESULTS:The protein levels of cGAS and STING in MU samples were significantly elevated when compared with the healthy controls by Western blot and IHC.After stimulation with cGAMP,real-time PCR and ELISA showed a dramatic increase of IFN-βand ISGs(containing CXCL10,IFIT1,and IL-6)in HCECs.Moreover,HCECs treated with cGAMP was characterized by increased phosphorylation and more nuclear translocation of IRF3.Meanwhile,increased p-IRF3 was observed in MU samples via IHC and Western blot.CONCLUSION:The pronounced expression of cGAS/STING signaling components in the patients with MU and probably contribute to the onset and development of MU.

Indications for penetrating keratoplasty and anterior lamellar keratoplasty during 2010-2017

AIM: To review the indications of penetrating keratoplasty(PK) and anterior lamellar keratoplasty(ALK) at Qingdao Eye Hospital, Shandong Eye Institute, Qingdao, China, from 2010 to 2017. METHODS: The data of all patients undergoing PK or ALK from January 2010 to December 2017 was retrospectively reviewed, with the indications during 2010-2013 and 2014-2017 compared. RESULTS: A total of 1869 eyes were included, among which 1405 eyes(75.2%) had PK and 464 eyes(24.8%) had ALK. The leading indications were suppurative keratitis(36.8%), keratoconus(15.5%), herpes keratitis(13.1%), and regraft(10.5%). In eyes undergoing PK, the top four indications were suppurative keratitis(38.7%), herpes keratitis(15.3%), keratoconus(12.6%), and regraft(12.5%) during 2014-2017, with the proportion of suppurative keratitis and herpes keratitis decreased while regraft and keratoconus increased compared with 2010-2013. In eyes with ALK, suppurative keratitis(30.8%), keratoconus(24.1%), corneal dystrophies and degenerations(10.6%), and corneal dermoid tumor(9.7%) were the top four indications, and there was no significant difference for the proportion of each indication between 2010-2013 and 2014-2017. CONCLUSION: Suppurative keratitis is the most common indication for PK and ALK at Qingdao Eye Hospital during 2010-2017, followed by keratoconus, herpes keratitis, and regraft. In eyes treated with PK, the proportion of suppurative keratitis and herpes keratitis decrease while regraft and keratoconus increase during 2014-2017 compared with 2010-2013.

Toxicity to the macula after using small doses cefuroxime for phacoemulsification and vitrectomy combined surgery

Dear Editor,Cefuroxime is a second-generation cephalosporin and a member of theβ-lactam family of antibiotics.Intracameral cefuroxime injection(1 mg/0.1 mL)during cataract surgery was found to be beneficial in reducing the risk of postoperative endophthalmitis[1-3].At the recommended dose of 1.0 mg in 0.1 mL,cefuroxime presents no ocular toxicity and is well tolerated[4-6].Acute macular edema with retinal detachment after cataract surgery is very rare[7].

Role of lncRNA MALAT1 in UVA-induced corneal endothelial senescence

The corneal endothelial monolayer is responsible for maintaining corneal transparency through its barrier and pump functions.Endothelial cells do not proliferate in vivo,and aging-related reductions in cell density make the endothelium fragile.1 However,the molecular mechanism associated with the aging corneal endothelium remains elusive.In this study,we used ultraviolet A(UVA)-light-induced senescence to mimic the degenerative endothelial changes during aging.MALAT1,the most abundant long non-coding RNA(lncRNA)gene in the cornea,was markedly down-regulated after UVA irradiation.The inhibition or activation of Malat1 expression genetically led to the aggravation or remission of the cellular aging phenotype after UVA irradiation.Furthermore,an in vitro model established by the human corneal endothelial cell line(HCEC)recapitulated the morphological and molecular changes during aging,encouraging the investigation of the underlying mechanisms.We observed changes in the mitochondrial bioenergetic profiles of HCECs accompanied by extensive cell aging and reduced reproductive capacity after MALAT1 was silenced by gene-targeting ASOs.Finally,Malat1 knockout(KO)aggravated mouse corneal endothelial senescence and dysfunction,which reinforced our conclusions.Our findings indicate that MALAT1 may contribute to the delay of aging processes involving endothelial cells and provide a new therapeutic target for treating aging-related corneal endothelium disorders.

Genomic instability and eye diseases

Background:Genetic information is stored in the bases of double-stranded DNA.However,the integrity of DNA molecules is constantly threatened by various mutagenic agents,including pollutants,ultraviolet light(UV),and medications.To counteract these environmental damages,cells have established multiple mechanisms,such as producing molecules to identify and eliminate damaged DNA,as well as reconstruct the original DNA structures.Failure or insufficiency of these mechanisms can cause genetic instability.However,the role of genome stability in eye diseases is still under-researched,despite extensive study in cancer biology.Main text:As the eye is directly exposed to the external environment,the genetic materials of ocular cells are constantly under threat.Some of the proteins essential for DNA damage repair,such as pRb,p53,and RAD21,are also key during the ocular disease development.In this review,we discuss five ocular diseases that are associated with genomic instability.Retinoblastoma and pterygium are linked to abnormal cell cycles.Fuchs’corneal endothelial dystrophy and age-related macular degeneration are related to the accumulation of DNA damage caused by oxidative damage and UV.The mutation of the subunit of the cohesin complex during eye development is linked to sclerocornea.Conclusions:Failure of DNA damage detection or repair leads to increased genomic instability.Deciphering the role of genomic instability in ocular diseases can lead to the development of new treatments and strategies,such as protecting vulnerable cells from risk factors or intensifying damage to unwanted cells.

Late postoperative opacification of a new type hydrophilic acrylic intraocular lens

Background:To report the clinical consequences and laboratory characteristics of late postoperative opacification of a hydrophilic acrylic intraocular lens(US-860UV IOL)as well as the prognosis of IOL replacement.Methods:Forty medical records(42 eyes)of patients with US-860UV IOL opacification reporting decreased or lost vision who underwent IOL explantation between 2017 and 2019 were reviewed.Explanted IOLs were analyzed by slit-lamp examination,confocal microscopy,scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS)at the Shandong Key Laboratory of Ophthalmology,Shandong Eye Institute,Shandong First Medical University,and Qingdao University of Science and Technology,Qingdao,China.Results:The mean age of the 40 patients was 74.837.57(63–92)years.The mean interval between cataract surgery and diagnosis of opacification was 32.388.76(17–48)months.Systemic diseases were found without statistical correlations,the most frequent being arterial hypertension,coronary heart disease,and diabetes mellitus.Visual acuity improved from 1.42±1.03 to 0.31±0.16(logMAR)after IOL replacement.SEM,EDS and alizarin red staining showed uniformly distributed,diffuse,milk-white opacification,with calcium and phosphorus deposits on the optic and haptic surfaces that could be dissolved in 1%HCl.Conclusions:Calcium and phosphorus deposition was the main cause of hydrophilic acrylic US-860UV IOL opacification.IOL replacement can safely and effectively improve the visual acuity of patients.