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Received 13 December 2013; revised 4 November 2014; accepted 9 November 2014; published online 9 December 2014, Purpose: To compare signs and symptoms of dry eye in keratoconus (KC) patients versus healthy subjects. Methods: A total of 15 KC patients (KC group, n = 15 eyes) and 16 healthy subjects (control group, 16 eyes) were enrolled in this study. The Schirmer I test with no anesthetic, tear break-up time (TBUT), corneal staining characteristics, and ocular surface disease index (OSDI) scores were evaluated for both groups. Impression cytology, combined with/scanning laser confocal microscopy (LCM), was performed to evaluate goblet cell density, mucin cloud height (MCH), and goblet cell layer thickness (CLT). Finally, tear concentrations of di-adenosine tetraphosphate (Ap4A) were assessed. Results were statistically analyzed using Shapiro–Wilk and non-parametric Wilcoxon rank sum tests. Statistical significance was set at p < 0.05. Results: KC patients had lower tear volumes and greater corneal staining than did healthy subjects (p < 0.05). OSDI scores were 44.96 ± 8.65 and 17.78 ± 6.50 for the KC and control groups, respectively (p < 0.05). We found no statistically significant differences in TBUT between groups. Impression cytology revealed lower goblet cell densities in KC group patients versus control group subjects (84.88 ± 32.98 and 128.88 ± 50.60 cells/mm,2 respectively, p < 0.05). There was a statistically significant reduction in MCH and CLT in KC group patients compared with control group subjects. Ap4A tear concentrations were higher in KC group patients than in control group subjects (2.56 ± 1.10 and 0.15 ± 0.12 µM, respectively, p < 0.05). Conclusions: The parameters evaluated in this study indicate that KC patients suffer greater symptoms of dry eye and greater tear instability, primarily due to the decreased mucin production in their tears, than do healthy patients with no KC., Depto. de Optometría y Visión, Unidad Docente de Bioquímica y Biología Molecular, Fac. de Óptica y Optometría, TRUE, pub

This study aims to describe how in-vivo confocal microscopy (ICVM) results improved diagnosis and treatment in three patients with complex corneal disorders at a single institution. Case one was a 36-year-old woman contact lens wearer referred to the hospital eye service (HES) by her community optician for a suspected corneal ulcer in her left eye. The case demonstrated that where laboratory cell culture was inconclusive, IVCM imaging improved diagnosis and more importantly adjusted the initial treatment till the complete resolution of the case. Case two was a shared-care 66-year-old keratoconus patient under a complex immunosuppression regime who had developed a recent series of post-surgical complications of fungal origin and was experiencing eye pain. IVCM was able to differentiate between an immune-mediated response and fungal keratitis and guide the clinicians towards an optimized treatment. Case three was a long-standing dry eye disease in a 64-year-old woman diagnosed with primary Sjögren’s syndrome where previous treatments failed to improve her symptomatology. IVCM was crucial for prescribing allogeneic serum eyedrops by anticipating early immune changes in the sub-basal corneal nerve plexus. In-vivo confocal microscopy can be an essential non-invasive imaging technique for improving clinicians’ diagnostic precision by adding a layer of certainty that other techniques may lack. Additionally, IVCM allows adjustment of the treatment accordingly, by instantly following any pathologic changes at the cellular level.

Since the introduction of silicone hydrogel contact lenses, many silicone-hydrogel materials have been produced, including water-gradient contact lenses with a silicone hydrogel core and a thin hydrogel outer layer (e.g., delefilcon A, verofilcon A, and lehfilcon A). Their properties have been investigated in various studies assessing both the chemical-physical characteristics and the comfort, but the overall picture is not always consistent. In this study, water-gradient technology is reviewed by looking at basic physical properties both in vitro and in vivo and at the interaction with the human ocular surface. Surface and bulk dehydration, surface wetting and dewetting, shear stress, interaction with tear components and with other environmental compounds, and comfort are discussed.

Purpose: To translate and validate an Italian version of the CLDEQ-8 (CLDEQ-8_IT). Methods: The study was carried out in two phases. In the first phase, a cross-cultural adaptation of CLDEQ-8 to Italian was performed by forward and backward translation in sequence. In the second phase, a multi-centre study was conducted for the validation of the questionnaire. Validity CLDEQ-8_IT was evaluated against three gestalt questions: overall opinion of soft contact lenses (CLs), global self-assessments of eye sensitivity and eye dryness. Reliability was evaluated by test–retest assessment in a subgroup of subjects. Finally, the psychometric properties of CLDEQ-8_IT were explored by Rasch analysis. Results: Two hundred and forty soft CL wearers, fluent Italian speakers (73 males and 167 females), between 18 and 70 years of age were enrolled. A significant correlation was found between CLDEQ-8_IT and each of the three Gestalt questions. The cutoff score of 12 points demonstrated the best balance between sensitivity and specificity in differentiating wearers grading their CLs as “Excellent/Very good” from those reporting their overall opinion as “Good/Fair/Poor”. The Intraclass Correlation Coefficient between test and retest was 0.88 (95% CI: 0.81–0.92). Finally, infit and outfit statistics using Rasch analysis for the 8 items were in a good range, however Principal Components Analysis revealed a certain degree of multi-dimensionality of the instrument. Also, item 8 analysis could be computed after merging the last two response categories. Conclusion: The CLDEQ-8_IT showed very good validity and reliability in measuring symptoms of CL wearers, comparable to the original English language version. A cut-off of 12 was confirmed as yielding the best balance between sensitivity and specificity in detecting CL wearers who could benefit from clinical management of their CL-related symptoms. Collapsing of the response options 5 and 6 in the last item of questionnaire could optimise it

Since the introduction of silicone hydrogel contact lenses, many silicone-hydrogel materials have been produced, including water-gradient contact lenses with a silicone hydrogel core and a thin hydrogel outer layer (e.g., delefilcon A, verofilcon A, and lehfilcon A). Their properties have been investigated in various studies assessing both the chemical-physical characteristics and the comfort, but the overall picture is not always consistent. In this study, water-gradient technology is reviewed by looking at basic physical properties both in vitro and in vivo and at the interaction with the human ocular surface. Surface and bulk dehydration, surface wetting and dewetting, shear stress, interaction with tear components and with other environmental compounds, and comfort are discussed.

Short Communication

When considering eye blinking from a tribological perspective, tear viscosity is expected to play a fundamental role. The application of rheological techniques to describe the tear film dates back to the late 1980s, but there has been a continuous need of reappraisal due to new findings in tear film biochemistry and to the development of new methods of physico-chemical characterization. This review provides an overview on tear rheological behavior by analyzing the peer-reviewed literature on this topic. Specifically, examples of in-vitro and in-vivo viscosity measurements are detailed, highlighting experimental criticalities and the need of a standard convention for rheological techniques to compare data across different studies, of analyses on tears of single individuals even within the limits of the low volume available, and of a further development of in-vivo techniques. Then, the controversial role of specific tear components on viscosity is discussed, together with the alterations associated to dry eye disease and contact lens wear. Finally, an updated focus is reported on the viscosity of artificial tears formulations.

Background: Patient-reported outcome measures (PROMs) can provide valuable insights on the impact of a disease or treatment on a patient’s health-related quality of life. In ophthalmology, particularly in dry eye disease (DED) and ocular surface disease (OSD), it is unclear whether the available PROMs were developed using comprehensive guidelines. To address this, we evaluated the methodological quality of studies assessing the psychometric properties of PROMs in DED and OSD [PROSPERO registration number CRD42019142328]. Methods: Four databases were searched; reference list and citation searching of included studies was also conducted. The COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist was used to appraise the quality of the studies evaluating the psychometric properties of PROMs used in DED and OSD. Results: The search strategy (S3 Table) retrieved 5,761 records, 573 duplicates were removed, 5,188 abstracts were screened and 127 full-text articles were retrieved for further review. Of these, 118 full-text articles did not meet the eligibility criteria and were excluded. Reference list and citation searching, identified an additional 8 articles bringing the total numbers of papers reviewed to 17. In general, psychometric properties such as content validity, measurement error and structural validity were not assessed by the studies included in this review. Studies reviewing The Impact of Dry Eye on Everyday Life (IDEEL) presented with the highest quality scores together with the Ocular Surface Disease Index (OSDI) questionnaire. Conclusions: The quality of studies evaluating PROMs in DED and OSD was considered using the COSMIN standards. The majority of the studies evaluating PROMs included in this review did not meet the recommended COSMIN criteria and the quality of the PROMs evaluated is not assured. Further evaluation of their psychometric properties is required if these are going to be used in clinical practice o

Purpose: To evaluate demographic and lifestyle factors associated with aqueous deficient and evaporative dry eye disease. Methods: A total of 1125 general public visitors (707 females, mean ± SD age, 33 ± 21, range 5–90 years) at the Royal Society Summer Science Exhibition were recruited in a cross-sectional study. A demographic and lifestyle factor questionnaire was administered, and dry eye symptomology (DEQ-5 score), ocular surface characteristics (conjunctival hyperaemia, and infrared meibography), and tear film parameters (tear meniscus height, non-invasive breakup time, and lipid layer grade) were evaluated for the left eye of each participant within a single session. The diagnostic criteria for dry eye disease subtypes were adapted from the rapid non-invasive dry eye assessment algorithm. Results: Overall, 428 (38%) participants fulfilled the diagnostic criteria for dry eye disease, 161 (14%) with aqueous deficient dry eye disease, and 339 (30%) with evaporative dry eye disease. Multivariate logistic regression demonstrated that advancing age, female sex, reduced sleep duration, higher psychological stress, and poorer self-perceived health status were independently associated with aqueous deficient dry eye disease (all p < 0.05). Significant risk factors for evaporative dry eye disease included advancing age, East and South Asian ethnicity, contact lens wear, increased digital device screen exposure, higher psychological stress, and poorer self-perceived health status (all p < 0.05). Conclusions: Both subtypes of dry eye disease were associated with several unique and shared demographic and lifestyle factors. The findings of this study could inform future research design investigating the utility of targeted screening and risk factor modification for the prevention and management of dry eye disease.

Received 10 May 2015; Revised 11 May 2016; Accepted 7 Jun 2016; Published online: 22 Jul 2016, Purpose: Based on the relationship between keratoconus and dry eye, the aim of this study was to evaluate changes in signs and symptoms of dry eye in keratoconus patients before and after intrastromal corneal ring surgery. Methods: Fifteen keratoconus patients were enrolled in Fundación Jiménez-Díaz of Madrid and University Clinic of Optometry of the Universidad Complutense de Madrid (Madrid, Spain). Tear break up time (TBUT), Schirmer test without anesthesia, corneal staining, diadenosine tetraphosphate (Ap4A) concentration, and ocular surface disease index (OSDI) were evaluated. Impression cytology combined with laser confocal microscopy was performed to evaluate goblet cell density, mucin cloud height (MCH), and cell layer thickness (CLT). All measurements were performed before (pre) surgery, 1 month (post) and 6 months after surgery (post6m). Results: We found no statistical differences in time in Schirmer test, TBUT, and corneal staining. OSDI scores were 44.96 ± 8.65, 26.30 ± 6.79, and 19.31 ± 4.28 for (pre), (post), and (post6m) surgery, respectively (p < 0.001). Impression cytology showed a decrease in cell density at (post6m) compared with presurgery (47.36 ± 35.15 cells/mm2 and 84.88 ± 32.08 cells/mm2, respectively, p = 0.04). At post6m, the MCH increased compared with presurgery values (13.97 ± 4.26 µm and 6.77 ± 2.51 µm, respectively, p < 0.001). There was a statistically significant increase in CLT in time. Ap4A tear concentrations were lower post6m than presurgery (1.02 ± 0.65 and 2.56 ± 1.10 µM, respectively, p < 0.001). Conclusion: Intrastromal corneal ring surgery induces changes improving dry eye symptoms but no changes were found in signs of dry eye after surgery in keratoconus patients except for the MCH that increases drastically. More studies are needed to clarify the reason of its improvement., Ministerio de Ciencia e Innovación (MICINN), Universidad Complutense de Madrid, Depto. de Optometría y Visión, Fac. de Óptica y Optometría, TRUE, pub

Received 15 April 2017, Revised 29 August 2017, Accepted 29 September 2017, Available online 6 October 2017., Objective: To study the influence of soft contact lens (SCL) central thickness and material in keratoconus on visual function after intracorneal ring segment (ICRS) surgery. Methods: A pilot, experimental, prospective, cross-sectional and double-blind study was performed. Fourteen keratoconus patients with age range of 34.75 ± 9.22 years (7 males and 7 females) with ICRS implanted were involved in the study. Two different SCL materials [Hioxifilcon A (G-5X/p-GMA/HEMA) and Lucifilcon A (silicone-hydrogel)] with four different central thicknesses (0.1, 0.2, 0.3 and 0.4 mm) were fitted in one eye per patient, selected randomly. High and low corrected distance visual acuity (CDVA) and contrast sensitivity (CS), corneal topography and corneal and total aberrometry were measured. Results: Corneal spherical like, coma like and root mean square (RMS) decreased significantly for 0.3 and 0.4 mm in both SCL materials (p < 0.05). Total RMS decreased significantly for 0.4 mm with both SCL materials (p < 0.05). High and low CDVA improved for 0.4 mm of thickness for both materials (p < 0.05). Statistically increasing were found in all thicknesses studied for CS in both materials (p < 0.05). Conclusion: A central thickness of the SCL equal or superior to 0.4 mm seems to decrease the ocular high order aberration (HOA) and to improve the visual function in keratoconus patients implanted with ICRS. However, the modulus of rigidity of the SCL would not influence the HOA correction., Ministerio de Economía y Competitividad (MINECO), Ministerio de Salud, Servicios Sociales e Igualdad de España, RETICS (Redes Temáticas de Investigación en Ciencias de la Salud) (España), Depto. de Optometría y Visión, Fac. de Óptica y Optometría, TRUE, inpress