Influencing factors of ocular pain in dry eye disease patients at high altitude

AIM:To quantify the severity and frequency of ocular pain in Tibetan plateau patients with dry eye,and to evaluate the related factors affecting ocular pain.METHODS:A retrospective study included 160 cases of dry eye disease(DED)patients who were treated from July 2022 to June 2023.Age,gender,occupation,illness course,anxiety,plateau duration,plateau protection,ocular surface disease index scale(OSDI),break-up time(BUT),Schirmer I test(SIT),conjunctivitis,history of ophthalmic medication,autoimmune disease,the workload of daily near vision range,smoking and overnight stay were obtained via comprehensive ophthalmic assessment,and their duration was followed up.Logistic regression analysis was used to determine the related factors affecting ocular pain.RESULTS:Totally 77.5%(124/160)of DED patients had ocular pain,of which the severity of ocular pain was mild,moderate,and severe in 30.0%,36.3%,and 11.3%of patients,respectively.Frequency of ocular pain was reported occasional,half the time,frequent,and persistent pain in 19.4%,36.9%,16.9%,and 4.4%.OSDI score was 19.67±5.70(13 to 36),and the level of pain was lowly correlated with OSDI(rs=0.316,P<0.001).Logistic regression showed that in plateau DED patients,increased anxiety led to increased severity and frequency of ocular pain[odds ratio(OR)=3.662,5.613,2.387,and 4.870;all P<0.05],professional eye protection and improvement of daily sleep quantity decreased pain(OR=0.307,0.572,0.418,and 0.789;all P<0.05),while smoking and general protection of plateau did not affect the severity and frequency of ocular pain(all P>0.05).CONCLUSION:Ocular pain is a common complaint in high-altitude DED patients during the pandemic.Anxiety,eye protection,and adequate sleep during the epidemic period are significantly associated with the severity and frequency of ocular pain in patients with plateau DED,while symptoms of DED have relatively little influence on them.

Intraocular pressure before and after capsulorhexis using two viscoelastic substances and two surgical approaches in enucleated porcine eyes

AIM:To investigate the influence of ophthalmic viscoelastic devices(OVDs)and different surgical approaches on the intraocular pressure(IOP)before and after creation of the curvilinear circular capsulorhexis(CCC)as a measure for anterior chamber stability during this maneuver.METHODS:Prospective experimental WetLab study carried out on enucleated porcine eyes.IOP was measured before and after CCC with the iCare Rebound tonometer(iCare ic200;iCare Finland Oy,Vantaa,Finland).The OVDs used were a cohesive one[Z-Hyalin,Carl Zeiss Meditec AG,Germany;hyaluronic acid(HA)]and a dispersive[Z-Celcoat,Carl Zeiss Meditec AG,Germany;hydroxy propylmethylcellulosis(HPMC)].The CCC was created using Utrata forceps or 23 g microforceps in different combinations with the OVDs.RESULTS:Using the Utrata forceps the IOP dropped from 63.65±6.44 to 11.25±3.63 mm Hg during the CCC.The use of different OVDs made no difference.Using the 23 g microforceps the IOP dropped from 65.35±8.15 to 36.55±6.09 mm Hg.The difference between IOP drop using either Utrata forceps or 23 g microforceps was highly significant regardless of the OVD used.CONCLUSION:Using the sideport for the creation of the capsulorhexis leads to a lesser drop in IOP during this maneuver compared to the main incision in enucleated porcine eyes.The use of different OVD has no significant influence on IOP drop.

Digital measuring the ocular morphological parameters of guinea pig eye in vivo with Python

AIM:To quantitatively measure ocular morphological parameters of guinea pig with Python technology.METHODS:Thirty-six eyeballs of eighteen 3-weekold guinea pigs were measured with keratometer and photographed to obtain the horizontal,coronal,and sagittal planes respectively.The corresponding photo pixels-actual length ratio was acquired by a proportional scale.The edge coordinates were identified artificially by ginput function.Circle and conic curve fitting were applied to fit the contour of the eyeball in the sagittal,coronal and horizontal view.The curvature,curvature radius,eccentricity,tilt angle,corneal diameter,and binocular separation angle were calculated according to the geometric principles.Next,the eyeballs were removed,canny edge detection was applied to identify the contour of eyeball in vitro.The results were compared between in vivo and in vitro.RESULTS:Regarding the corneal curvature and curvature radius on the horizontal and sagittal planes,no significant differences were observed among results in vivo,in vitro,and the keratometer.The horizontal and vertical binocular separation angles were 130.6°±6.39°and 129.8°±9.58°respectively.For the corneal curvature radius and eccentricity in vivo,significant differences were observed between horizontal and vertical planes.CONCLUSION:The Graphical interface window of Python makes up the deficiency of edge detection,which requires too much definition in Matlab.There are significant differences between guinea pig and human beings,such as exotropic eye position,oblique oval eyeball,and obvious discrepancy of binoculus.This study helps evaluate objectively the ocular morphological parameters of small experimental animals in emmetropization research.

AB016.Cholinergic enhancement reduces the temporary shift in perceptual eye dominance induced by a few hours of monocular occlusion

Background:A few hours of monocular deprivation with a diffuser eye patch temporarily strengthens the contribution of the deprived eye to binocular vision.This shift in favour of the deprived eye is characterized as a form of adult visual plasticity.Studies in animal and human models suggest that neuromodulators can enhance adult brain plasticity in general.Specifically,acetylcholine has been shown to improve certain aspects of visual function and plasticity in adulthood.We investigated whether a single administration of donepezil(a cholinesterase inhibitor)could further augment the temporary shift in perceptual eye dominance that occurs after two hours of monocular patching.Methods:We conducted three experiments to investigate whether donepezil enhances the shift in perceptual eye dominance induced by monocular patching.In each experiment,healthy adults completed two experimental sessions while taking either donepezil(5 mg,oral)or a placebo(lactose)pill.In experiment 1 we patched the non-dominant eye for 2 hours and measured ocular balance with a binocular phase combination task.In experiment 2 we patched for one hour to investigate whether donepezil shortens the amount of time necessary to observe a shift in ocular dominance.In experiment 3 we patched for 2 hours and measured ocular balance with a binocular rivalry task to see if the effect of donepezil was comparable across the two tasks.We calculated AUCs for the shift in perceptual eye dominance across five time points after removing the patch to compare our treatment conditions in each experiment.Results:Donepezil significantly reduces the magnitude and duration of the shift in perceptual eye dominance produced by both 2(P<0.01)and 1 hours(P<0.05)of monocular patching when measuring ocular balance with a binocular phase combination task.Donepezil also reduces the magnitude of the shift in ocular dominance when measuring balance with a binocular rivalry task.Conclusions:Previous studies have demonstrated that cholinergic potentiation enhances adult brain plasticity.Because of this,we hypothesized donepezil would further augment the strength of the deprived eye after patching.Our study demonstrates that enhanced cholinergic potentiation actually interferes with the consolidation of the perceptual eye dominance plasticity induced by several hours of monocular deprivation.These results contribute to the growing evidence that cholinergic potentiation enhances certain forms of adult brain plasticity at the expense of others.

Ocular Trauma in a Rural Population of North China:The Handan Eye Study

Objective To determine the prevalence of ocular trauma and the proportion of blindness and visua impairment due to trauma in a rural population in northern China. Methods The Handan Eye Study is a population-based cross-sectional study that surveyed 6830 Chinese people aged 30＋ years from 13 randomly selected villages in Yongnian County, city of Handan, Hebei Province, in July, 2006. All participants underwent a standardized interview and extensive examinations. A structured questionnaire was used to collect information on ocular trauma. Results Of the 5837 participants who filled out the questionnaire, 124 subjects [2.1%; 95% confidence interval （CI）, 1.8%-2.5%] reported a history of ocular trauma in either eye, including 19 （0.3%） persons reporting trauma in both eyes. Men were more likely to have an eye injury than women [odds ratio （OR）, 3.3; 2.2-4.9]. In multiple logistic regression models, ocular trauma was significantly more frequent among normotensive participants when compared with hypertensive participants （hypertensive vs. normotensive＂ OR, 0.6; 0.4-0.9） and among participants who had a history of falls （OR, 2.4; 1.2-4.8）. The proportion of unilateral visual impairment and unilateral blindness due to trauma were 10.5% （13 subjects） and 21.0% （26 subjects）, respectively. Conclusion Our study reports the prevalence of severe ocular trauma among adults in rural China, revealing a high proportion of blindness and visual impairment due to trauma. These findings suggest the need for educational strategies to increase eye health awareness in this rural population with focus on providing at least appropriate first aid care to reduce blindness due to trauma.

Early changes to dry eye and ocular surface after smallincision lenticule extraction for myopia

AIM： To investigate the early changes in dry eye symptoms, tear function and ocular surface following small-incision lenticule extraction（SMILE） for myopia.·METHODS： Ninety-seven consecutive patients（193 eyes）who underwent SMILE for myopia were observed in this longitudinal and retrospective study. Parameters evaluated included： subjective dry eye symptoms（dryness, foreign body sensation and photophobia）, tear film breakup time（TBUT）, Schirmer Ⅰ test without anesthesia（S Ⅰ T）, tear meniscus height（TMH） and corneal fluorescein staining. Each parameter was evaluated before, and subsequently at 1d, 1wk, 1 and3 mo after surgery.·RESULTS： Compared with preoperative data, dryness was noted to be significantly increased at 1wk and 1mo postoperatively（P 〈0.01）. Symptoms of photophobia and foreign body sensation demonstrated significant differences at 1d and 1wk as compared with preoperative scores respectively（P 〈0.01）. These values were decreased at 1 and 3mo post-surgery（P 〉0.05）.Conversely the corneal staining scores were higher than the preoperative data at 1d, 1wk and 1mo（P 〈0.01）, but were close to the preoperative level at 3mo postoperatively. There was a significant decrease in TMH at 1wk and 1mo（P 〈0.01）, but the value was close to the preoperative level at 3mo postoperatively（P =0.16）. The examination outcomes of S Ⅰ T were significantly increased at 1d then reduced at 1wk after surgery（P 〈0.01）. Each value subsequently returned to the baseline value at 1 and 3mo（P 〉0.05）. TBUT was significantly decreased at all postoperative time points（P 〈0.01）.· CONCLUSION： SMILE resulted in mild dry eye symptoms, tear film instability and ocular surface damages; however, these complications can recover in a short period of time.

Reliability of Chinese web-based ocular surface disease index questionnaire in dry eye patients:a randomized,crossover study

AIM:To assess the reliability of web-based version of ocular surface disease index in Chinese(C-OSDI)on clinically diagnosed dry eye disease(DE)patients.METHODS:A total of 254 Chinese participants(51%male,129/254;mean age:27.90±9.06 y)with DED completed paper-and web-based versions of C-OSDI questionnaires in a randomized crossover design.Ophthalmology examination and DED diagnosis were performed prior to the participants being invited to join the study.Participants were randomly designated to either group A(paper-based first and webbased second)or group B(web-based first and paper-based second).Final data analysis included participants that had successfully completed both versions of the C-OSDI.Demographic characteristics,test-retest reliability,and agreement of individual items,subscales,and total score were evaluated with intraclass correlation coefficients(ICC),Spearman rank correlation,Wilcoxon test and Rasch analysis.RESULTS:Reliability indexes were adequate,Pearson correlation was greater than 0.8 and ICCs range was 0.827 to 0.982;total C-OSDI score was not statistically different between the two versions.The values of mean-squares fit statistics were very low compared to 1,indicating that the responses to the items by the model had a high degree of predictability.While comparing the favorability 72%(182/254)of the participants preferred web-based assessment.CONCLUSION:Web-based C-OSDI is reliable in assessing DED and correlation with the paper-based version is significant in all subscales and overall total score.Webbased C-OSDI can be administered to assess individuals with DED as participants predominantly favored online assessment.

Efficacy of Isotonic Seawater Solution on Inflammation of the Ocular Surface in Matrix Metalloproteinase MMP-9-Positive Dry Eye Disease Patients

Purpose: Prospective study to evaluate the anti-inflammatory efficacy of isotonic seawater solution on metalloproteinase 9 (MMP-9) levels in the tears of patients with dry eye disease (DED). Methods: A total of 50 patients were included, with the following dry eye criteria in both eyes: InflammaDry? test initially positive, ocular surface disease index (OSDI) score ≥ 12 and <33, tear film breakup time (TBUT) ≤ 10 seconds, Shirmer I test result ≤ 10 mm/5 minutes, corneal staining ≥ 1. Additionally, all the patients selected corresponded to a dry eye type 2 - 3 severity degree - mild and moderate - Dry Eye Workshop Study (DEWS) classification. The InflammaDry test is used to measure levels of MMP9 at the beginning and the end of the study. All patients were treated exclusively with isotonic seawater solution 5 times a day for 3 weeks. Results: The InflammaDry test was positive in 100% of the patients (n = 50) and in 100% (n = 100) of the eyes before treatment. In 14 (28%) patients the test became negative in both eyes, and in 15 (30%) it was negative in one of the eyes. In 43% (n = 43) of the positive eyes, MMP-9 became undetectable in the tear fluid following treatment with isotonic seawater. This change was statistically significant (p < 0.001). Conclusions: The washes with ophthalmic isotonic seawater solution have a significant impact on inflammation of the ocular surface in dry eye disease, with an ability to make MMP-9 levels negative in 43% of cases.

Comparison of Artisan iris-claw intraocular lens implantation and posterior chamber intraocular lens sulcus fixation for aphakic eyes

AIM:To compare the efficacy and complications of Artisan iris-claw intraocular lens(IOL)implantation and posterior chamber IOL sulcus fixation for the treatment of aphakic eyes without capsular support after vitrectomy.METHODS:A prospective study of 45 cases was conducted.Forty-five eyes without sufficient lens capsule support following pars plana vitrectomy(PPV)combined lens extraction were divided into two groups.Group A:25 eyes received Artisan iris-claw IOL implantation.Group B:20 eyes received posterior chamber IOL sulcus fixation.The corrected distance visual acuity(CDVA)and intraocular pressure(IOP),corneal endothelial cell loss rate,surgical time and complications were compared between the two groups.Pigment changes of trabecular meshwork and anterior chamber depths were measured at each time point in Artisan group.RESULTS:The mean surgical time of Artisan group was significantly shorter(P【0.05).No statistically significant difference in endothelial cell loss rate was noted between two groups at any time point(P】0.05).CDVA of Artian group was better than that of the sulcus fixation group 1d after surgery(P【0.05)and there was no statistically significant difference 1 and 3mo after surgery(P】0.05).Mean IOP showed no significant differences between groups before and after surgery.The postoperative complications of Artisan group were anterior uveitis,iris depigmentation,pupillary distortion and spontaneous lens dislocation.The complications of sulcus fixation group include choroidal detachment,intraocular haemorrhage,tilt of IOL optic part and retinal detachment.CONCLUSION:Secondary Artisan IOL implantation canbe performed less invasively and in a shorter surgical time period with earlier visual recovery after surgery compared to transscleral suturing fixation of an IOL.This technique is an effective and safe procedure.It is a promising option for the treatment of aphakic eyes without capsular support after vitrectomy.

Human eye ocular component analysis for refractive state and refractive surgery

AIM： To analyze the clinical factors influencing the human vision corrections via the changing of ocular components of human eye in various applications; and to analyze refractive state via a new effective axial length.METHODS： An effective eye model was introduced by the ocular components of human eye including refractive indexes, surface radius（r1, r2, R1, R2） and thickness（t, T） of the cornea and lens, the anterior chamber depth（S1） and the vitreous length（S2）. Gaussian optics was used to calculate the change rate of refractive error per unit amount of ocular components of a human eye（the rate function M）. A new criterion of myopia was presented via an effective axial length.RESULTS： For typical corneal and lens power of 42 and 21.9 diopters, the rate function Mj（j=1 to 6） were calculated for a 1% change of r1, r2, R1, R2, t, T（in diopters） M1=＋0.485, M2=-0.063, M3=＋0.053, M4=＋0.091, M5=＋0.012, and M6=-0.021 diopters. For 1.0 mm increase of S1 and S2, the rate functions were M7=＋1.35, and M8=-2.67 diopter/mm, respectively. These rate functions were used to analyze the clinical outcomes in various applications including laser in situ keratomileusis surgery, corneal cross linking procedure, femtosecond laser surgery and scleral ablation for accommodation.CONCLUSION： Using Gaussian optics, analytic formulas are presented for the change of refractive power due to various ocular parameter changes. These formulas provide useful clinical guidance in refractive surgery and other related procedures.

Analysis of postoperative ocular surface changes and intervention effect after pars plana vitrectomy in meibomian gland dysfunction dry eye patients

AIM:To observe ocular surface changes after phacovitrectomy in patients with mild to moderate meibomian gland dysfunction(MGD)-type dry eye and track clinical treatment response using a Keratograph 5M and a Lipi View interferometer.METHODS:Forty cases were randomized into control group A and treatment group B;the latter received meibomian gland treatment 3d before phacovitrectomy and sodium hyaluronate before and after surgery.The average non-invasive tear film break-up time(NITBUTav),first noninvasive tear film break-up time(NITBUTf),non-invasive measured tear meniscus height(NTMH),meibomian gland loss(MGL),lipid layer thickness(LLT)and partial blink rate(PBR)were measured preoperatively and 1wk,1 and 3mo postoperatively.RESULTS:The NITBUTav values of group A at 1wk(4.38±0.47),1mo(6.76±0.70),and 3mo(7.25±0.68)were significantly lower than those of group B(7.45±0.78,10.46±0.97,and 11.31±0.89;P=0.002,0.004,and 0.001,respectively).The NTMH values of group B at 1wk(0.20±0.01)and 1mo(0.22±0.01)were markedly higher than those of group A(0.15±0.01 and 0.15±0.01;P=0.008 and P<0.001,respectively);however,there was no difference at 3mo.The LLT of group B at 3mo[91.5(76.25-100.00)]significantly exceeded that of group A[65.00(54.50-91.25),P=0.017].No obvious intergroup difference was found in MGL or PBR(P>0.05).CONCLUSION:Mild to moderate MGD dry eye worsens in the short term after phacovitrectomy.Preoperative cleaning,hot compresses,and meibomian gland massage as well as preoperative and postoperative sodium hyaluronate promote the rapid recovery of tear film stability.

Ocular Manifestations in Thyroid Eye Disorder: A Cross-Sectional Study from Nepal

Background: Thyroid eye disease represents an organ-specific autoimmune process that is usually associated with thyroid disease. Graves’ disease is the most common thyroid abnormality associated with thyroid eye disease. Aim: This study was conducted for the profile of ocular manifestation in Thyroid Eye Disease (TED). Methodology: A cross-sectional study of 117 cases of thyroid dysfunction was carried out at BP Koirala Institute of Health System, out of which 84 (71.79%) cases had ocular manifestation. They were evaluated and analyzed in detail and the characteristics documented included patient’s demography, ocular and systemic history and as well as ocular examination and some of the systemic and laboratory findings. Results: In this study, mean age of presentation of TED was 39.7 years. 59 patients were female and 25 were male. The maximum patients of both sexes were in the fourth decade of their lives. The common lid signs were lid retraction and lid lag. Proptosis was seen in 33.3% of cases out of which 68% had bilateral proptosis. Corneal ulcer was seen in 7.1% and optic neuropathy in 1.2% of cases. In 27.3% of cases there was elevation of IOP. Dry eye was seen in 61.9% of cases and POAG seen in 8.3% of cases. In the study population 75% were hyperthyroiditic, 16.7% were hypothyroiditic and 8.3% were in euthyroid state. Conclusion: Female was more commonly affected. The maximum number of patients of both sexes was in the fourth decade of their lives. Hyperthyroidism patient had greater chance of ocular manifestation.

Effect of 0.01%atropine eyedrops on intraocular pressure in schoolchildren:a randomized clinical trial

·AIM:To assess the effect of 0.01%atropine eye drops on intraocular pressure(IOP)in myopic children.·METHODS:A placebo-controlled,double-masked,randomized study.Totally 220 children aged 6 to 12 y with myopia ranging from-1.00 to-6.00 D in both eyes were enrolled.Children were randomized in a 1:1 ratio to either 0.01%atropine eye drops or a placebo group using generated random numbers.All participants underwent the examination of IOP and cycloplegic refraction at baseline,6 and 12 mo.The change of IOP and the proportion of subjects with increased IOP in atropine and placebo groups were compared.·RESULTS:Of 220 children,117 were boys(53.2%).A total of 159(72.3%)participants completed the follow-up at the 1-year study.At baseline,the mean IOP was 15.74 mm Hg(95%CI,15.13 to 16.34 mm Hg)for the 0.01%atropine group and 15.59 mm Hg(95%CI,15.00 to 16.19 mm Hg)for placebo group(mean difference,0.14 mm Hg;P=0.743)after adjusting for central corneal thickness at baseline.At one year follow-up,the mean change of IOP was 0.16 mm Hg(95%CI,-0.43 to 0.76 mm Hg)for the 0.01%atropine group and-0.11 mm Hg(95%CI,-0.71 to 0.50 mm Hg)for placebo group(mean difference,0.27 mm Hg;P=0.525)after adjusting for central corneal thickness.The 51.4%of children have increased IOP in the 0.01%atropine group,compared with 45.9%in the placebo group(P=0.511).·CONCLUSION:The 0.01%atropine eye drops do not significantly affect the risk of elevated IOP.It is relatively safer to use in the studies that try to minimize myopia progression.However,a further long-duration study is required to be validated.

Comparison of intraocular pressure readings with Perkins,Tonopen,iCare 200,and iCare Home to manometry in cadaveric eyes

AIM:To compare intraocular pressure(IOP)readings obtained with Perkins tonometry,i Care Home,i Care 200,and Tonopen to IOP readings obtained with the manometer of a perfusion system to assess the accuracy and reproducibility of each method of tonometry at set pressures.METHODS:The IOP of human cadaveric eyes(n=2)was measured using a manometer inserted into the eye through the optic nerve.IOP measurements were obtained using a Perkins tonometer,i Care Home,i Care 200,and Tonopen.These measurements were compared to set point IOP measurements of a manometer to determine accuracy and reproducibility of each device.RESULTS:Mean IOP readings obtained with the Perkins tonometer compared to manometer readings demonstrated a difference of-1.0±5.0 mm Hg(P=0.45),indicating a lower reading on average than manometery although not significant.Mean IOP difference between iCare 200 and manometer was 5.3±2.2 mm Hg(P<0.0001).Mean difference in IOP between iCare Home and manometer was 3.5±2.4 mm Hg(P=0.0004).Mean IOP difference compared to manometer was 4.6±4.0 mm Hg for the Tonopen(P<0.0001).IOP measurements obtained with the Perkins tonometer demonstrated a standard deviation of 5.0 mm Hg while the Tonopen measurements demonstrated a 4.0 mm Hg standard deviation.In comparison,iCare 200 and iCare Home demonstrated 2.2 and 2.4 mm Hg standard deviation,respectively.CONCLUSION:Applanation tonometry produces more accurate IOP readings than rebound tonometry or Tonopen,however it demonstrates greater variability than the other forms of tonometry.Rebound tonometry is more reproducible but tends to over-estimate IOP.

Ocular surface microbiota in patients with varying degrees of dry eye severity

AIM:To elucidate the profiles of commensal bacteria on the ocular surfaces of patients with varying severity of dry eye(DE).METHODS:The single-center,prospective,case-control,observational study categorized all participants into three distinct groups:1)control group(n=61),2)mild DE group(n=56),and 3)moderate-to-severe DE group(n=82).Schirmer’s tear secretion strips were used,and the bacterial microbiota was analyzed using 16S ribosomal ribonucleic acid gene sequencing.RESULTS:The three groups had significant differences in alpha diversity:the control group had the highest richness(Chao1,Faith’s phylogenetic diversity),the mild DE group showed the highest diversity(Shannon,Simpson),and the moderate-to-severe DE group had the lowest of the above-mentioned indices.DE severity was positively correlated with a reduction in beta diversity of the microbial community,with the moderate-to-severe DE group exhibiting the lowest beta diversity.Linear discriminant analysis effect size presented distinct dominant taxa that significantly differed between each.Furthermore,the exacerbation of DE corresponded with the enrichment of certain pathogenic bacteria,as determined by random forest analysis.CONCLUSION:As DE severity worsens,microbial community diversity tends to decrease.DE development corresponds with changes in microbial constituents,primarily characterized by reduced microbial diversity and a more homogenous species composition.

Severe prelenticular membrane formation on the surface of a hydrophilic acrylic intraocular lens after cataract surgery in an eye with an Ahmed valve implant

【正】Dear Sir,Iam Yong-Sun Ahn,from the Department of Ophthalmology of St.Vincent Hospital of Suwon,Kyungki-do,South Korea.Cataracts are a common problem in eyes with a glaucoma drainage device(GDD),because tube shunt surgery increases the incidence and progression of cataracts[1].An Ahmed valve,the most commonly inserted GDD,is composed of a silicone tube connected to a flat plate sewn to the sclera,and aqueous humor flows from the

Experimental platform for moving double-camera system based on binocular vergence eye movements

A control model of binocular vergence eye movements is presented. The control model can reduce blind areas caused by the double cameras in motion platform. In order to validate the model performance, an experimental platform and its control system based on TMS320LF2407 are designed. The control system has its compacted configuration and high reliability. The simulation and experimental results show that the control system can realize binocular vergence movements. Compared with the conventional moving double cameras system, this new system can considerably reduce blind areas.

Distribution and associated factors of intraocular pressure in the older population:Tehran Geriatric Eye Study

AIM:To determine the distribution and associated factors of intraocular pressure(IOP) in an Iranian elderly population 60 years of age and above.METHODS:The present report is part of the Tehran Geriatric Eye study(TGES),a population-based cross-sectional study that was conducted on the residents of Tehran 60 years of age and above.The sampling was performed using multistage stratified random cluster sampling methods from 22 districts of Tehran,Iran.Demographic and history information,blood samples,and blood pressure were collected from all participants.Ocular examinations included measurement of uncorrected and best-corrected visual acuity,objective and subjective refraction,and slit-lamp biomicroscopy.The IOP was measured using Goldmann applanation tonometry(GAT).Corneal imaging and ocular biometry were performed using Pentacam AXL.RESULTS:The data of 3892 eyes of 2124 individuals were analyzed for this report.The mean age of the study participants was 66.49±5.31y(range:60 to 95y).The mean IOP was 15.2 mm Hg(95%CI:15.1 to 15.4),15.3 mm Hg(95%CI:15.1 to 15.5) and 15.1 mm Hg(95%CI:15.0 to 15.3) in all participants,males,and females,respectively.Of the study participants,1.3% had an IOP of ≥20 mm Hg.The mean IOP increased from 15.1 mm Hg in the age group 60-64y to 16.3 mm Hg in the age group ≥80y.According to the final multiple GEE model,the IOP was statistically significantly higher in men than in women.All the studied age groups,except for the 75-79-year-old age group,had significantly higher IOP compared to the 60-64-year-old age group.The IOP was significantly higher in underweight compared to other body mass index groups.Moreover,the IOP had a statistically significant direct relationship with the mean corneal power(mean CP),central corneal thickness(CCT),and systolic blood pressure.CONCLUSION:The present study presents the distribution of IOP in an Iranian elderly population.A higher IOP(within the range 14 to 17 mm Hg) is significantly associated with older age,male sex,high systolic blood pressure,increased mean CP,and CCT.These factors should be considered in the clinical interpretation of IOP.

Ocular surface and tear film changes after eyelid surgery

Eyelid surgery is widely and extensively used in facial plastic and reconstructive surgeries.There are many categories of eyelid surgeries,the most common of which include blepharoplasty,ptosis surgery,and eyelid reconstruction.In many cases,these procedures are combined,and there are many different techniques for each type of operation.Upper eyelid blepharoplasty usually includes the excision of skin,preseptal orbicularis oculi muscle,and orbital fat.Common methods of lower eyelid blepharoplasty are the skin-muscle flap,the skin flap,and the transconjunctival.Ptosis surgery is mainly divided into three types:transcutaneous,transconjunctival,and sling surgery.Surgeons often used the Hughes or Cutler-Beard Bridge Flaps in eyelid reconstruction.Different types and methods of surgery have their own advantages and disadvantages,and postoperative complications may occur.Therefore,postoperative complications of eyelid surgeries,such as dry eye symptoms,should be taken into serious consideration.Relevant literature involving these complaints can be found in PubMed by searching the terms“dry eye”,“eyelid”,“surgery”,and other related keywords.Moreover,various ocular surface and tear film alterations may be detected using the Ocular Surface Disease Index(OSDI),tear film breakup time,Schirmer test,fluorescein staining,and lissamine green staining after various eyelid surgeries.As dry eye disease is prevalent in the general population,it is more urgent to figure out what we can learn from these complaints.Further exploration in this field may help surgeons to choose a better surgical method and give an accurate evaluation of the postoperative effect.

Changes in ocular surface status and dry eye symptoms following femtosecond laser-assisted cataract surgery

AIM: To observe the changes in ocular surface and the dry eye symptoms following femtosecond laser-assisted cataract surgery(FLACS). METHODS: Patients with no eye signs or symptoms in Guangzhou Aier Eye Hospital between October 2017 and September 2018, who underwent FLACS and intraocular lens(IOL) implantation for age-related cataract were enrolled. Tear film stability assessed with OCULUS Keratograph 5 M, Schirmer’s I test(SIT), and corneal fluorescein staining(CFS) were evaluated before and after surgery at 1 d, 1 wk, 1, and 3 mo in order. Ocular Surface Disease Index scores(OSDI) and Subjective Symptom Questionnaires(SSQs) were recorded at the same time point.RESULTS: Thirty-eight eyes of 38 patients were enrolled. The noninvasive tear film break-up time(first break-up time and average break-up time) decreased in a peak at the 1 wk visit, and then increased to basic levels at 1 mo. The tear meniscus height(TMH) increased transiently at 1 d, and declined in the following 3 mo visits. The SIT had a transient increase at 1 d(P=0.357) and a decrease at 1 wk and 1 mo(both P<0.05) but returned to the preoperative levels at 3 mo after surgery(P=0.062). CFS scores were significantly improved compared with those before surgery, and had a statistical difference(P<0.05). OSDI scores and SSQs after surgery were obviously higher, and had a statistical difference(P<0.001) but didn’t return to the basic level by 3 mo. CONCLUSION: Dry eye signs and symptoms can occur immediately following FLACS and have a peak severity on day 7 postoperatively. Most signs of dry eye can return to preoperative basic levels within 3 mo postoperatively. However, all cases can not recover from CFS and dry eye symptoms at 3 mo postoperatively.