泪膜动态改变对视觉质量的影响

泪膜的动态变化包括泪膜厚度、脂质层和泪膜破裂区域的动态变化.干眼患者常伴有视力波动,泪膜对视觉质量的作用主要取决于泪膜的同质性及均匀性.近年来使用Hartmann-Shack波前像差仪、视觉质量分析系统等仪器定量连续测量健康眼及干眼瞬目后持续睁眼状态时及其应用人工泪液后泪膜动态改变对视觉质量影响.正常人瞬目后持续睁眼视觉质量下降,高阶像差和客观散射指数呈现出与干眼相似的上升趋势.干眼患者泪膜动态改变较正常人出现更早,高阶像差和客观散射指数均较正常眼增大.长期使用人工泪液可以改善干眼患者泪膜稳定性及瞬目后的视觉质量.视觉质量的动态检测可反映泪膜动态变化,有助于敏感地发现泪膜不稳定,及早进行临床诊治.     

Short tear film breakup time-type of dry eye in India

Purpose:The aim of this study was to describe the clinical characteristics and risk factors of short tear film break-up time (TBUT) type of dry eye disease and compare it with other types of dry eye diseases.Methods:This cross-sectional study included 570 patients (≥ 20 years) from the outpatient department using systematic random sampling.Results:The age-adjusted prevalence of short TBUT type of dry eye disease was 5.4% (95% confidence interval: 3.2–6.8%). There was no difference (P > 0.05) between the total and subscale scores of the Ocular Surface Disease Index^® questionnaire between patients with short TBUT and those with aqueous tear deficiency. Both these groups differed significantly (P < 0.05) in the findings of TBUT, Schirmer I test, and Lissamine green staining score. The common symptoms in patients with short TBUT type of dry eye disease were eye fatigue (25.4%), heaviness in the eye (19.7%), and an uncomfortable sensation (14.1%). The symptoms in the aqueous tear deficiency group were light sensitivity (28.2%), dryness (19.2%), burning (13.0%), foreign body sensation (12.8%), and blurring of vision (14.1%). The risk factors associated with short TBUT type of dry eye disease were the presence of meibomian gland dysfunction (odds ratio: 3.759 [95% confidence interval: 2.135–6.618], P < 0.0001) and female sex [odds ratio: 1.954 (95% confidence interval: 1.042–3.667), P = 0.037].Conclusion:Patients with short TBUT type of dry eye disease have symptom severity similar to aqueous tear-deficient dry eyes, but the pattern is different. The finding of this type of dry eye disease in India indicates its global presence, and ophthalmologists should consider it in their differential diagnoses.     

Prophylactic action of lipid and non-lipid tear supplements in adverse environmental conditions: A randomised crossover trial

PurposeTo evaluate the prophylactic benefits of lipid-based and non-lipid-based artificial tear lubricants, in dry eye disease, after adverse environmental exposure.MethodsTwenty-eight participants with dry eye disease were recruited in a prospective, double-masked, randomised crossover trial. On separate days, participants were randomised to receive a single application of a lipid-containing tear supplement (Systane Complete) to one eye, and a non-lipid containing eye drop (Systane Ultra) to the contralateral eye. Participants were then exposed to a previously validated simulated adverse environment. Symptoms, non-invasive tear film breakup time, lipid layer grade, and tear meniscus height were assessed at three time points; baseline, following eye drop instillation, and after exposure to the adverse environment.ResultsBoth treatments effected improvements in symptoms and non-invasive tear film stability following instillation (all p < 0.05), although an improvement in lipid layer quality was limited to the lipid-containing nano-emulsion tear supplement (p = 0.003). Although protective effects were conferred by both treatments following exposure to the simulated adverse environment, more favourable symptomology scores, non-invasive tear film stability, and lipid layer quality were observed in the lipid-containing tear supplement group (all p < 0.05). No significant changes were observed in tear meniscus height in both treatment groups (all p > 0.05).ConclusionsBoth the lipid and non-lipid-based artificial tear supplement demonstrated prophylactic benefits in a simulated adverse environment. However, the ability to preserve tear film quality and reduce dry eye symptomology was greater with the lipid-containing eye drop.Trial registration numberACTRN12619000361101     

Systemic risk factors of dry eye disease subtypes: A New Zealand cross-sectional study

PurposeTo evaluate systemic risk factors of dry eye disease, aqueous tear deficiency, and meibomian gland dysfunction.MethodsThree hundred and seventy-two community residents (222 females, 150 males; mean ± SD age, 39 ± 22 years) were recruited in a cross-sectional study. Past medical history, dry eye symptomology, ocular surface characteristics, and tear film quality were evaluated for each participant within a single clinical session. The diagnosis of dry eye disease, aqueous tear deficiency, and meibomian gland dysfunction were based on the global consensus recommendations of the Tear Film and Ocular Surface Society's Dry Eye Workshop II (TFOS DEWS II) and International Workshop on Meibomian Gland Dysfunction.ResultsOverall, 109 (29%) participants fulfilled the TFOS DEWS II criteria for dry eye disease, 42 (11%) had aqueous tear deficiency, and 95 (26%) had meibomian gland dysfunction. Multivariate logistic regression analysis demonstrated that systemic rheumatologic disease and antidepressant medication were independently associated with aqueous tear deficiency (both p < 0.05). Significant risk factors for meibomian gland dysfunction included age, East Asian ethnicity, migraine headaches, thyroid disease, and oral contraceptive therapy (all p ≤ 0.01).ConclusionsBoth etiological subtypes of dry eye disease were associated with a number of systemic risk factors. These findings would support routine systemic inquiry of dry eye disease and associated systemic conditions and medications, in order to facilitate opportunistic screening and timely inter-disciplinary referral where necessary.     

Characterising the ocular surface and tear film in a population-based birth cohort of 45-year old New Zealand men and women

PurposeTo assess the prevalence of dry eye disease, aqueous tear deficiency, meibomian gland dysfunction, and asymptomatic ocular surface disease in a population-based cohort of 45-year-old New Zealand men and women.MethodsThis cross-sectional study of 885 participants (442 females, 443 males) was based on a population-representative birth cohort of individuals born between April 1 1972 and March 31 1973 in Dunedin, New Zealand (the Dunedin Multidisciplinary Health and Developmental Study). Participants were assessed at 45 years of age, and dry eye symptomology, ocular surface characteristics, and tear film quality were evaluated for each participant within a single clinical session. The diagnosis of dry eye disease was made according to the validated rapid non-invasive dry eye assessment algorithm.ResultsClinical dry eye signs were present in 402 (45%) participants, of which 78 (9%) participants fulfilled the diagnostic criteria for dry eye disease, and 322 (37%) had asymptomatic ocular surface disease. Among participants with dry eye disease, 22 (2%) exhibited aqueous tear deficiency, and 65 (7%) had meibomian gland dysfunction. Females were more likely to be affected by dry eye disease, meibomian gland dysfunction, and asymptomatic ocular surface disease (all p < 0.05).ConclusionsClinical dry eye signs were present in almost half of this population-based cohort of 45-year-old New Zealanders, although only 9% of participants fulfilled the diagnostic criteria for dry eye disease. The high prevalence of asymptomatic ocular surface disease presents an opportunity for preventative public health intervention.     

Impact of tear optics on the repeatability of Pentacam AXL wave and iTrace in measuring anterior segment parameters and aberrations

Purpose:To assess impact of tear optics on repeatability of a Scheimpflug device with a Hartmann Shack aberrometer and a ray tracing aberrometer.Methods:One hundred healthy and 100 postrefractive surgery eyes underwent dry eye evaluation including Schirmer’s test and tear film break-up time (TBUT). They underwent optical quality analyzer (OQAS, Visio metrics S.L, Terrassa, Spain) to assess objective scatter index (OSI), three scans each on Pentacam AXL wave (OCULUS Optikgerate Gmbh, Wetzlar, Germany), iTrace (Tracey™ Technologies, Texas, USA) for flat, steep keratometry, thinnest corneal thickness, root mean square higher-order aberrations (RMS HOA), RMS lower-order aberrations (LOA), spherical aberrations, RMS COMA. Repeatability of Pentacam AXL wave and iTrace in healthy and postrefractive eyes (OSI >1 vs OSI <1) was studied using within-subject standard deviation (Sw) test–retest repeatability (TRT), coefficient of variation (COV).Results:OSI showed an inverse association with TBUT (P < 0.001). All measurements with Pentacam AXL wave with OSI < 1 had excellent repeatability, intraclass correlation coefficient (ICC) ranging from 0.88 for HOA, to 0.92 for LOA. The Sw, TRT, and COV of all aberration measurements were significantly lower (better) than those of iTrace. In eyes with OSI ≥1, the repeatability with Pentacam AXL wave dropped with ICC ranging from 0.77 for HOA, to 0.84 for LOA with lower Sw, TRT, and COV of all aberration measurements as compared to iTrace. Maximum variation was seen with HOA and minimum with LOAConclusion:Tear optics affected repeatability of Pentacam wave and iTrace. Pentacam wave had better repeatability in eyes with a poor tear film as compared to iTrace. Thus, the tear film can impact repeatability of an instrument and it is important to assess the tear film prior to imaging patients, which can change the way we interpret and image these patients.     

Tear film normalization test: a new diagnostic test for dry eyes

PURPOSE: To evaluate the normalization of the tear film (tear film normalization test [TNT]) as a diagnostic test for dry eye syndrome. METHODS: The uncorrected distance vision of 20 patients with dry eyes (40 eyes) and 20 normals (40 eyes) before and after instillation of carboxymethyl cellulose 0.5% (CMC; Refresh Plus; Allergan, Irvine, CA) was recorded. We used study early treatment diabetic retinopathy (ETDRS) vision charts to test vision in each eye. Tear film breakup time (TBUT), presence or absence of superficial punctate erosions (SPE), tear film meniscus height, meibomian gland function, and ocular surface disease index (OSDI) questionnaire scores were evaluated. RESULTS: CMC improved visual acuity in the dry eye group (P < 0.0001). Response operator's curve (ROC) analysis showed that vision improvement of 2 lines or more after tear normalization was associated with an 82.5% (95% CI: 66.6%-92.1%) sensitivity and 100% (95% CI: 89.1%-100%) specificity for dry eye. There was a significant correlation between vision improvement and OSDI score in the dry eye group (P = 0.003). CONCLUSION: The TNT is a highly sensitive and specific test for dry eyes and is available in every eye care professional's office. The more symptomatic the dry eye, the greater the improvement.     

Meibomian gland dropout is associated with immunodeficiency at HIV diagnosis: Implications for dry eye disease

AimTo characterize anterior eye health and tear film characteristics in individuals with human immunodeficiency virus (HIV) undergoing anti-retroviral therapy.MethodsThis cross-sectional study involved 35 adults, categorized as healthy controls (n = 18) or as HIV-positive patients (n = 17), with no history of opportunistic infection or current ocular fundus abnormalities. Participants underwent a comprehensive anterior eye assessment. Primary outcome measures were dry eye symptoms (Ocular Surface Disease Index survey), tear film osmolarity, and extent of meibomian gland dropout. Secondary outcomes measures were ocular redness, tear film stability, and ocular surface staining. Levels of 36 cytokines were assayed from basal tears using a multiplex bead array.ResultsThe HIV-positive group showed more extensive meibomian gland dropout relative to controls (mean ± SD, controls: 29.6 ± 5.8 versus 37.0 ± 13.9%, p = 0.045). The extent of meibomian gland dropout was negatively correlated with blood CD4 T-cell count (a marker of immunodeficiency) at diagnosis (r = −0.69, p = 0.006). All other tests of anterior ocular health, including dry eye symptom levels, were not significantly different between the groups. There were no significant inter-group differences for the 36 cytokines assayed in the tear film.ConclusionsWe find greater meibomian gland dropout in HIV-positive individuals that is related to disease severity at diagnosis. Given this feature predisposes to dry eye disease, it suggests the need for long-term studies of anterior eye health in people with HIV.     

Ageing and the natural history of dry eye disease: A prospective registry-based cross-sectional study

PurposeTo investigate the impact of ageing on ocular surface parameters, and empirically determine optimal prognostic cut-off ages for clinical markers of dry eye disease, aqueous tear deficiency, and meibomian gland dysfunction.MethodsA total of 1331 community residents (785 females, 546 males; mean ± SD age, 38 ± 19 years) were recruited in a prospective registry-based cross-sectional study. Dry eye symptomology, ocular surface characteristics, and tear film quality were evaluated for each participant within a single clinical session, in accordance with the global consensus recommendations of the TFOS DEWS II reports.ResultsMultivariate regression analysis demonstrated positive associations between ageing and clinical markers of dry eye disease (all p ≤ 0.001). The Youden-optimal prognostic cut-off ages for signs of meibomian gland dysfunction occurred during the third decade of life (24–29 years); the optimal predictive ages for lid wiper epitheliopathy, tear film instability, hyperosmolarity, and dry eye symptoms occurred during the fourth decade of life (31–38 years); while the optimal prognostic thresholds for signs of aqueous tear deficiency and ocular surface staining occurred in the fifth and sixth decades of life (46–52 years).ConclusionsAdvancing age is a significant risk factor for dry eye disease, which represents a growing public health concern with the ageing population worldwide. Signs of meibomian gland dysfunction appeared earlier in the natural history of disease progression, and the brief delay prior to the development of other clinical dry eye signs might represent a window of opportunity for preventative interventions in the young adult age group.     

El ojo seco está relacionado con un aumento intrasujeto de la variabilidad de osmolaridad lagrimal confirmado por tecnología de aprendizaje de máquinas

ObjectiveBecause of high variability, tear film osmolarity measures have been questioned in dry eye assessment. Understanding the origin of such variability would aid data interpretation. This study aims to evaluate osmolarity variability in a clinical setting.Material and methodsTwenty dry eyes and 20 control patients were evaluated. Three consecutive osmolarity measurements per eye at 5 min intervals were obtained. Variability was represented by the difference between both extreme readings per eye. Machine learning techniques were used to quantify discrimination capacity of tear osmolarity for dry eye.ResultsMean osmolarities in the control and dry eye groups were 295.1 ± 7.3 mOsm/L and 300.6 ± 11.2 mOsm/L, respectively (P = .004). Osmolarity variabilities were 7.5 ± 3.6 mOsm/L and 16.7 ± 11.9 mOsm/L, for the control and dry eye groups, respectively (P < .001). Based on osmolarity, a logistic classifier showed an 85% classification accuracy.ConclusionsIn the clinical setting, both mean osmolarity and osmolarity variability in the dry eye group were significantly higher than in the control group. Machine learning techniques showed good classification accuracy. It is concluded that higher variability of tear osmolarity is a dry eye feature.     

Does Sjogren's syndrome affect only the lacrimal gland in the eye? Time to replace the missing stones

Purpose:This study aimed to reveal the cause of meibomian gland disease and meibomian gland loss in patients with Sjögren''s syndrome (SS) as the leading factor for dry eyes.Methods:The study included a total of 30 patients with SS and dry eye symptoms and a control group of 50 age- and gender-matched healthy subjects. The dryness parameters of all the participants were evaluated. At first, meibography was performed to measure meibomian gland loss using noninvasive methods. Later, meibomian gland expression and secretion quality were evaluated using silt-lamp biomicroscopy. Correlations between the measurements were analyzed statistically.Results:In patients with SS, MG loss was significantly greater than in the control group (19.7 ± 71%, 12.7 ± 9.6%, P < 0.001). All dry eye parameters (tear film breakup time, Schirmer''s test score, OSDI, stain score, dry eye disease) were statistically significant in the SS group. There was an extremely negative correlation between upper MB loss and BUT (P = 0.08, r: 0.781). There was an extremely positive correlation between upper MB loss and staining (P = 0.015, r: 0.739). An extremely negative correlation was determined between sub-MB loss and BUT (P = 0.18, r:-0.781), and a moderately positive significant correlation was found between sub-MB loss and staining (P = 0.031, r: 0.659).Conclusion:The results of this study demonstrated that patients with SS were at a higher risk of being exposed to meibomian gland loss, which directly leads to the severe dry eye symptoms associated with SS.     

Tear film lipid layer alterations in allergic conjunctivitis

PURPOSE: To assess the alterations of the tear film lipid layer and tear functions in patients with seasonal allergic conjunctivitis (SAC) and to compare the results with healthy control subjects. METHODS: Seventy-eight eyes of 39 consecutive patients diagnosed as SAC (mean age 32.6 years; 11 male, 28 female) as well as 20 eyes of 10 healthy control subjects (mean age 32.5 years; 6 male, 4 female) underwent slit-lamp examinations, tear film breakup time measurements (BUT), corneal fluorescein stain scoring, Schirmer test, and tear film lipid layer interferometry. The 2 groups were then compared for the examined parameters. RAST and serum IgE level evaluations were also carried out in the patients to confirm the diagnosis of allergy. RESULTS: The mean BUT was 3.4 +/- 1.5 seconds in patients with SAC compared with the mean value of 12.4 +/- 2.4 seconds in the controls (P < 0.05). There were no significant differences in relation to Schirmer test values between the 2 groups; 78% of the patients with SAC had grade 3 or above dry eye change in tear film lipid layer interferometry, whereas none of the controls had an interferometry grade greater than 3 (grade 1-2 normal; grade 3-4 dry eye; grade 5 severe dry eye). Eyes with SAC had significantly higher tear film lipid layer thickness ranges compared with the control eyes (P < 0.05). CONCLUSION: SAC was associated with advanced tear instability and thickening of the tear film lipid layer. Evaluation of the tear film lipid layer thickness might be useful in the assessment of the extent of dry eye disease and the treatment outcomes in patients with allergy.     

A phase II randomized trial to evaluate the long-term (12-week) efficacy and safety of OC-01 (varenicline solution) nasal spray for dry eye disease: The MYSTIC study

PurposeDry eye disease is characterized by loss of tear film stability. OC-01 (varenicline solution) is a small-molecule nicotinic acetylcholine receptor agonist administered as a nasal spray that stimulates tear production.MethodsIn MYSTIC (NCT03873246) patients aged ≥22 years with dry eye disease were randomized 1:1:1 to OC-01 0.03 mg, OC-01 0.06 mg, or vehicle (n = 41 per group), administered twice daily via intranasal spray, for 12 weeks (84 days). Primary efficacy endpoint was mean change from baseline in anesthetized Schirmer's test score (STS) in study eye at day (D) 84.ResultsPatients receiving OC-01 0.03 and 0.06 mg had statistically significantly increased tear production at D84 versus vehicle; least squares mean changes from baseline in STS were 10.8 mm and 11.0 mm for OC-01 0.03 and 0.06 mg, respectively. A trend toward a higher proportion of patients experiencing ≥10-mm improvement in STS from baseline was observed with OC-01 0.03 mg (36.6%; p > 0.05), and was significant for OC-01 0.06 mg (48.8%; p = 0.024), versus vehicle (24.4%). Non-ocular treatment-emergent adverse events (TEAEs) were reported by 21 patients; the most common was sneezing (OC-01 0.03 mg, 2 [4.9%]; OC-01 0.06 mg, 3 [7.3%]), with similar frequencies between treatment groups. No severe or serious TEAEs were reported.ConclusionsOC-01 (varenicline solution) nasal spray improved tear production in patients with dry eye disease over a long-term (12-week) period, and represents a receptor neuro-activator with a nasal route of administration that spares the ocular surface to stimulate tear production.     

干眼症患者对比敏感度的测定

目的:研究干眼症对比敏感度的变化及通过对比敏感度测试来评价人工泪液对干眼症患者视功能的影响。方法:确诊为干眼症患者25例50眼和正常人15例29眼,分别测量BUT(泪膜破裂时间)、SⅠt(泪液分泌基础实验)和泪膜干涉图像,并采用OPTEC6500视功能测试仪分别测量干眼症患者和正常人应用人工泪液前后的对比敏感度。主要观察指标包括BUT、SⅠt、泪膜干涉图像及低、中、高频CS。结果:本研究中按临床症状、BUT,SⅠt和泪膜干涉图像试验结果将受试者分为干眼症组和正常对照组,两组年龄比较无统计学差异。干眼症患者低、中、高频CS均低于正常组(P<0.05)。应用人工泪液5min后,发现干眼症组低、中、高频CS都有显著提高(P<0.05);且干眼症组应用人工泪液后的对比敏感度与对照组相近。结论:干眼症的低对比敏感度可以通过人工泪液的使用加以改善,通过人工泪液治疗不但可以缓解症状而且使干眼症的视觉质量接近正常人标准;另外,对比敏感度测试可以作为一种客观的非接触的评价泪膜质量的方法,为干眼症的治疗疗效提供客观依据。     

Evaluation of dry eye disease in children with blepharokeratoconjunctivitis

ObjectiveTo evaluate the symptoms and signs of dry eye disease (DED) in children diagnosed with blepharokeratoconjunctivitis (BKC).DesignProspective case-controlled studyParticipantsConsecutive patients with BKC and normal controls.MethodsAll participants underwent a comprehensive dry eye assessment including the Canadian Dry Eye Assessment (CDEA) questionnaire, tear film osmolarity test, Schirmer's test without anesthesia, slit lamp examination, tear film break-up time, corneal fluorescein staining (CFS), and lissamine green conjunctival staining (LGCS), according to the Sjögren's International Collaborative Clinical Alliance ocular staining score. For each test the result of the more severe eye was included in the statistical analysis.ResultsTwenty-five patients were recruited—11 with BKC and 14 healthy controls. No difference in symptoms was found between children with BKC (CDEA score 6.1 ± 5.5) and normal controls (CDEA score 3.6 ± 3.2; p = 0.16). Children with BKC had significantly higher mean CFS (1.1 ± 1.6 vs 0.1 ± 0.4; p = 0.04) but similar mean LGCS (1.4 ± 1.8 vs 1.5 ± 2.1; p = 0.81) than normal controls. No statistically significant differences were observed in other tests between the 2 groups. CDEA scores were significantly correlated to CFS in normal controls (r = 0.59, p = 0.03), and approached significance in children with BKC (r = 0.56, p = 0.07).ConclusionsThe only test that can distinguish DED in patients with BKC from children without BKC is the CFS score. This should guide management and monitoring of this unique patient population with DED symptoms and signs.     

Comparison of the Objective Optical Quality in Keratoconus Patients after Penetrating Keratoplasty versus Lamellar Keratoplasty

Objective: To evaluate the optical quality of keratoconus patients after penetrating keratoplasty (PKP) or lamellar keratoplasty (LKP) using a dual-channel optical quality analysis system (OQAS). Methods: This was a prospective study. A total of 40 keratoconus patients in Qingdao Eye Hospital were involved in thisstudy from January 2016 to December 2017. And they were divided into a PKP group (23 patients, 24 eyes) or LKP group (17 patients, 19 eyes), depending on the surgical selection. Visual acuity, astigmatism, the density of the corneal endothelium cells, objective scatter index (OSI), predicted visual acuity (PVA), modulation transfer function cut-off frequency (MTF cutoff), Strehl ratio (SR) and tear film analysis of the mean OSI with a dual-channel optical quality analysis system were compared. Data were analyzed using χ2 test and independent t test. Results: There was no statistically significant difference between the PKP group and the LKP group for best corrected visual acuity, and spherical and cylindrical powers. But there was a significant difference between the two groups in the density of the corneal endothelium cells (t=3.91, P<0.001). In addition, there were statistically significant differences between the PKP and the LKP groups for the MTF cutoff and PVA100 (t=2.58, P=0.01; t=2.66, P=0.01). There was also a statistically significant difference between the PKP group and the LKP group in the tear film analysis mean OSI (t=3.48, P<0.001). Conclusions: The objective optical qualities of keratoconus patients after PKP measured by OQAS are better than after LKP, and the MTF cutoff and contrast vision are also better.     

穿透性角膜移植术与板层角膜移植术治疗圆锥角膜术后客观视觉质量比较

目的：探讨采用双通道视觉质量分析系统（OQAS）评估圆锥角膜患者行穿透性角膜移植术（PKP）和 板层角膜移植术（LKP）后的客观视觉质量。方法：前瞻性临床研究。收集2016年1月至2017年12 月在青岛眼科医院因圆锥角膜行角膜移植的患者40例进行研究,其中PKP组23例（24眼）,LKP组 17例（19眼）,术前2组患者最佳矫正视力、屈光度和临床分期差异均无统计学意义,术后随访并应 用OQAS检查术后的客观视觉质量,检查指标包括客观散射指数（OSI）、调制传递函数（MTF）截止 频率、客观对比度视力和泪膜质量OSI变化。分类变量比较采用χ2 检验,组间连续变量比较采用独 立样本t检验。结果：术后随访23～25个月,PKP组和LKP组患者角膜植片均保持透明状态,2组间 最佳矫正视力、球镜度和柱镜度差异均无统计学意义,但PKP组角膜内皮细胞计数明显低于LKP组 （t=3.91,P<0.001）。PKP组的斯特列尔比、20%对比度视力、9%对比度视力以及OSI与LKP组相比, 差异均无统计学意义。PKP组的MTF截止频率和100%对比度视力较LKP组高,差异均有统计学意 义（t=2.58,P=0.01;t=2.66,P=0.01）。泪膜质量OSI在LKP组明显高于PKP组,差异有统计学意义 （t=3.48,P<0.001）。结论：双通道OQAS测量结果表明圆锥角膜患者行PKP术后的客观视觉质量优 于行LKP术后,PKP术后的MTF截止频率和对比度视力高于LKP术后。     

Comparison of the effects of first and second generation silicone hydrogel contact lens wear on tear film osmolarity Running title:Tear film osmolarity and silicone hydrogel contact lens wear

AIM: To evaluate the outcomes of pars plana vitrectomy (PPV) without the use of an ocular tamponade in patients having tractional retinal detachment (TRD) secondary to proliferative diabetic retinopathy (PDR).METHODS: It was an interventional study conducted at the Department of Ophthalmology, B.V. Hospital, Bahawalpur, Pakistan, from July 2011 to July 2012. A total of 75 patients (84 eyes) having TRD secondary to PDR were treated by PPV without using an ocular tamponade. All patients included in the study had a tractional retinal detachment secondary to proliferative diabetic retinopathy but didn’t have or develop retinal breaks before or during the study period. The surgical procedure included a PPV combined with the removal of the tractional retinal membranes and the application of endolaser photocoagulation to the retina. The mean follow-up period was 12 months.RESULTS:Successful retinal reattachement was observed in 78 of the operated eyes (92.8%). In these patients, the retina remained attached till the end of the one year follow-up period. Improvement in best corrected visual acuity (BCVA) was seen in 63 eyes (75%). The visual acuity remained unchanged in 9 eyes (10.7%). Mean improvement in BCVA was 2.00+1.24 at baseline to 1.24+1.22 (P<0.05) at the end of the follow-up period.CONCLUSION: In the absence of the retinal breaks, a TRD secondary to PDR can be successfully treated by pars plana vitrectomy without the use of an ocular tamponade.     

Ocular Surface Disease Index© and the five-item dry eye questionnaire: A comparison in Indian patients with dry eye disease

Purpose:To compare the suitability of the Ocular Surface Disease Index (OSDI) and the 5-item Dry Eye Questionnaire (DEQ-5) in Indian patients with dry eyes.Methods:This cross-sectional study evaluated the OSDI and DEQ-5 in patients with tear film abnormalities. Tear film breakup time, tear film height, Schirmer’s I, lissamine green staining, and meibomian gland expressibility were performed on each patient.Results:There were 101 patients with symptoms and/or signs of tear film abnormality. Both OSDI and DEQ-5 questionnaires significantly correlated (ρ = 0.566, P < 0.0001) with each other. The OSDI questionnaire showed a good correlation with all dry eye tests, whereas the DEQ-5 correlated significantly only with the tear film breakup time and the lissamine green score. None of the questionnaires correlated with meibomian gland expressibility. The Bland–Altman analysis revealed a marginal bias (−0.01 unit) for DEQ-5. The DEQ-5 scored higher in patients with mild symptoms. While 101 (100%) patients answered all the questions in the DEQ-5, only 19 (18.8%) patients answered all the questions in the OSDI questionnaire. The least responses were recorded in the vision-function-related and environmental trigger subscales of the OSDI.Conclusion:The OSDI and DEQ-5 scores showed a moderate correlation. The OSDI questionnaire correlated with a higher number of dry eye tests than the DEQ-5. The large number of skipped questions in the vision-function-related and environmental trigger subscales of the OSDI suggests that the questionnaire is not adequately adapted to the Indian population. Patients with a negative OSDI score should be reassessed with the DEQ-5 to exclude symptom positivity.     

Peripapillary retinal nerve fibre layer thickness measurement with SD-OCT in normal and glaucomatous eyes:distribution and correlation with age

AIM:To determine peripapillary retinal fiber layer thickness (RNFL) measured with spectral domain optical coherence tomography (SD-OCT) in normal and glaucomatous eyes in a large sample of exclusively white population and compare results with other similarly constructed studies.METHODS:Average, maximum, minimum and per quadrant RNFL thickness were measured in normal and glaucomatous Greek patients with a scanning laser ophthalmoscope (SLO)/SD-OCT device. The effect of age in normal RNFL thickness was also determined.RESULTS: A total of 278 normal (278 patients) and 67 glaucomatous (67 patients) eyes were included in the study. Average RNFL thickness was 114.8±13.3μm in normal and 92.1±18.5μm in glaucomatous eyes (P<0.001). In normal discs, superior quadrant was the thickest, followed by the inferior, nasal and temporal. Decline of normal RNFL thickness with age was statistically significant for average RNFL thickness (1.92μm per decade of life) and for the superior and inferior quadrants of the disc.CONCLUSION:SD-OCT peripapillary RNFL measurements can be used to distinguish between normal and glaucomatous eyes and establish normative databases, since normal disc measurements differ between different ethnic groups and between different SD-OCT devices.