Effect of Artificial Tears on Visual Performance in Subjects With Dry Eye

Dry Eye Treatment with Intense Pulsed Light for Improving Visual Outcomes After Cataract Surgery with Diffractive Trifocal Intraocular Lens Implantation

Background/Objectives: Meibomian gland dysfunction (MGD)-related dry eye aggravates postoperative visual outcomes in cataracts. Diffractive trifocal intraocular lenses (IOLs) decrease contrast sensitivity (CS). Intense pulsed light (IPL) improves tear film stability and ocular surface conditions in MGD-related dry eyes. We investigated the effect of preoperative MGD-related dry eye treatment combining manual meibomian gland expression (MGX) with IPL (IPL-MGX) on visual outcomes post-cataract surgery with diffractive trifocal IOL implantation. Methods: In this single-center, prospective, and open-label study, we enrolled 67 patients (134 eyes) with MGD-related dry eye undergoing cataract surgery on both eyes. Preoperatively, IPL-MGX was performed on one eye (IPL-MGX group) but not the contralateral eye (control group). Tear break-up time, high-order aberrations, and central superficial punctate keratopathy (C-SPK) were assessed. CS and corrected distance visual acuity were analyzed. Differences between groups were analyzed at 1 week, 1 month, and 3 months postoperatively. Results: The IPL-MGX group showed greater mean tear break-up time and lower mean high-order aberration and C-SPK values after preoperative IPL treatment and postoperatively (all p < 0.01). Postoperative CS was higher in the IPL-MGX group at 1 week (all spatial frequencies) (p < 0.01 [cpd = 2.9, 4.5, 7.1, and 10.2] and p < 0.05 [cpd = 1.1 and 1.8]); 1 month [2.9-10.2 cpd] (p < 0.01); and 3 months [4.5-10.2 cpd] (p < 0.01 [cpd = 10.2] and p < 0.05 [cpd = 4.5 and 7.1]) postoperatively. Mean corrected distance visual acuity was higher in the IPL-MGX group only postoperatively (p < 0.01). Conclusions: Preoperative MGD-related dry eye treatment using IPL-MGX enhances tear film stability, ocular surface conditions, and visual outcomes, potentially improving postoperative vision quality and patient satisfaction.

Preliminary Application of a Continuous Functional Contrast Visual Acuity System in the Assessment of Visual Function in Dry Eye Patients

Purpose

To investigate the feasibility and efficacy of a continuous functional contrast visual acuity (CFCVA) system in the assessment of visual function in dry eye disease (DED).

Methods

Twenty patients with DED and 15 normal controls were recruited. Subjective symptoms were evaluated using the Ocular Surface Disease Index (OSDI) questionnaire, and tear film stability was assessed by a noninvasive corneal topographer. Under natural blinking conditions, the custom-built CFCVA system was used to take serial visual acuity measurements at 100%, 25%, 10%, and 5% contrast for 60 seconds. A 5-minute measurement at a 100% contrast level was defined as the stress test (ST). Mean CFCVA was defined, and visual maintenance ratio (VMR) was the ratio of mean CFCVA divided by baseline visual acuity.

Results

In both groups, VMR decreased and mean CFCVA (logarithm of the minimum angle of resolution) increased with decreasing optotype contrast (from 100% to 5%). In ST, the ST VMR at the fourth and fifth minutes (VMR54 and VMR55) showed the strongest correlations with OSDI total, ocular symptoms, and vision-related function (-0.646 and -0.598, -0.688 and -0.693, and -0.599 and -0.555, respectively, P < 0.05). VMR54 and VMR55 also demonstrated the best discriminating ability for detecting DED, with areas under the curve of 0.903 and 0.867, respectively.

Conclusions

Extending the continuous measuring time was more effective for detecting vision-related functional abnormalities in patients with DED than simply decreasing the optotype contrast level.

Translational Relevance

The proposed CFCVA system and associated parameters offer a potential method for quantifying and interpreting the visual symptoms of DED in clinical care.

Customized designed notch filters and applied effects on glare and contrast sensitivity in patients with dry eye syndrome

PURPOSE

Glare visual acuity and contrast sensitivity are important indicators of visual quality. Studies have shown that the glare visual acuity and contrast sensitivity in dry eye patients tend to degenerate, further affecting their quality of life. The objective of this study was to investigate the effect of notch filters on glare VA and contrast sensitivity in patients with dry eye or with dry eye syndrome.

METHOD

36 subjects in the 20‒65 age group were diagnosed as having dry eye disease or perceived dry eye syndromes themselves who were included after the initial screening with the OSDI questionnaire, and one was subsequently excluded as they had undergone retinal detachment surgery. Finally, 35 subjects (14 male and 21 female) with a mean age of 40.66 ± 15.62 years participated in this study. All subjects wore their habitual prescriptions and four different filter lenses (namely 480, 620, dual 480 & 620 notch filter, and FL-41 tinted lens), and measured the parameters of glare visual acuity and contrast sensitivity using CSV-1000 and sine wave contrast test (SWCT), respectively. Student t-test and Repeated measurement analysis (R-ANOVA) were utilized by using SPSS 26.0 software.

RESULTS

A dual-wavelength 480 & 620 nm optical notch filter had a significant anti-glare effect decreasing glare disabilities or discomfort, and leading to better visual quality, the same effect was also shown on a 480 nm notch filter lens. All participants showed a significant difference among the baseline, three notch filters (480 nm, 620 nm, dual-wavelength 480 & 620 nm), and FL-41 tinted lens were used on SWCT_A (1.5 cpd, F = 3.054, p = 0.019) and SWCT_E (18 cpd, F = 2.840, p = 0.049); but did not show statistical different on SWCT_B (3 cpd, F = 0.333, p = 0.771), SWCT_C (6 cpd, F = 1.779, p = 0.159), and SWCT_D (12 cpd, F = 1.447, p = 0.228). The baseline showed the best visual performance on CS at a low spatial frequency (SWCT_A, 1.5 cpd), any filter might reduce the contrast sensitivity at low spatial frequencies in the clinical trial, whereas 480 nm notch filter showed the best effectiveness on CS at a high spatial frequency (SWCT_E, 18 cpd), the FL-41 lens that also filters out the 480 nm band does not achieve the same effect. Moreover, patients with dry eye or those older than 40 years old preferred optical multilayer notch filters to FL-41 tinted lenses.

CONCLUSION

The 480- & 620-nm dual-wavelength and 480-nm single-wavelength notch filters have the best effect on the glare visual acuity and contrast sensitivity (CS) at high spatial frequencies in dry eye patients. The 620-nm notch filter performs better in CS at low and mid-low spatial frequencies; the FL-41 tinted lens performs poorly for glare VA and CS spatial frequencies examination. Patients with glare disabilities or CS disturbance at high spatial frequencies may choose a 480-nm notch filter lens, and patients who have CS disturbance at low spatial frequencies may consider a 620-nm notch filter for the prescription.

Funktionelle Sehschärfe beim Trockenen Auge

Das Trockene Auge führt häufig zu Sehstörungen trotz guter Sehleistung in der Standardvisusprüfung. Die Beschwerden treten meist beim Lesen, Arbeiten am Computer und/oder beim Autofahren auf. Grund ist die schlechte optische Qualität der Augenoberfläche beim Trockenen Auge mit Zunahme von topometrischer Irregularität und Asymmetrie, Anstieg des irregulären Astigmatismus, Zunahme der kornealen und okulären Aberrationen höherer Ordnung, Abnahme der Kontrastsensitivität und Zunahme der Lichtstreuung. Die funktionelle Sehschärfe repräsentiert die Visusfunktion im Zeitverlauf und reflektiert die Visusleistung eines Individuums bei täglichen Aktivitäten. Sie ist beim Trockenen Auge signifikant reduziert im Vergleich zu Normalprobanden. Eine Vielzahl von Testmethoden zur Evaluierung der funktionellen Sehschärfe wurde beschrieben. Kein Verfahren hat sich bisher in der täglichen Praxis durchgesetzt.

Improvement in Contrast Sensitivity Function after Lacrimal Passage Intubation in Eyes with Epiphora

This prospective case series aimed to investigate the contrast sensitivity function before and after lacrimal passage intubation (LPI) in eyes with epiphora due to lacrimal passage obstruction. We included 58 eyes of 51 patients who underwent LPI for lacrimal passage obstruction. The best-corrected visual acuity (BCVA), contrast sensitivity function, and lower tear meniscus were compared before LPI and one month after lacrimal duct stent removal. The area under the log contrast sensitivity function (AULCSF) was calculated for the analyses. Lower tear meniscus was assessed using anterior segment optical coherence tomography. The BCVA was comparable (p = 0.61) before and after LPI, while AULCSF increased significantly after treatment (before LPI: 1.29 ± 0.17, after LPI: 1.37 ± 0.14, p < 0.0001). Treatment resulted in a significant increase in contrast sensitivity at all spatial frequencies, 3-18 cycles/degree (p < 0.01 for 3, p < 0.01 for 6, p < 0.0005 for 12, p < 0.05 for 18 cycles/degree). The lower tear meniscus parameters improved significantly after treatment (p < 0.005); however, no correlation between the changes in the tear meniscus and those of the AULCSF was found. The contrast sensitivity significantly improved after LPI in eyes with epiphora due to lacrimal passage obstruction.

Deterioration of contrast sensitivity in eyes with epiphora due to lacrimal passage obstruction

Purpose

Epiphora causes deterioration in contrast sensitivity in some eye diseases. This study was conducted to investigate contrast sensitivity in eyes with epiphora caused by lacrimal passage obstruction.

Methods

This single-center, prospective case series enrolled 57 patients with unilateral lacrimal passage obstruction. The best-corrected visual acuity (BCVA), contrast sensitivity function, and lower tear meniscus of the affected and contralateral unaffected eyes were compared. The area under the log contrast sensitivity function (AULCSF) was calculated.

Results

The BCVA did not significantly differ between the affected and contralateral eyes, while the AULCSF was significantly lower in the affected eyes than that in the contralateral eyes (median 1.35, interquartile range 1.22–1.44 vs. median 1.36, interquartile range 1.28–1.46, P = 0.032). Lower tear meniscus parameters were significantly higher in the affected eyes than those in the contralateral eyes (P < 0.005).

Conclusions

The contrast sensitivity function is significantly diminished in eyes with epiphora caused by lacrimal passage obstruction.

[Tear film analysis and evaluation of optical quality: A review of the literature (French translation of the article)]

Dry eye is a complex multifactorial disease of the ocular surface and tears. It is associated with ocular surface symptoms and is one of the most common causes for ophthalmologic consultation. Despite their frequent use in clinical practice, the usual tests to evaluate dry eye and ocular surface disease-history of symptoms, tear break-up time (TBUT), Meibomian gland evaluation, corneal fluorescein staining, Schirmer test-have shown low reproducibility and reliability. In addition, subjective symptoms are often weakly or poorly correlated with objective signs. Since the tear film is the first system through which light must pass, the optical quality of the eye is highly dependent on the homogeneity of the tear film. Various investigative methods have been developed to evaluate both the structural and functional quality of the tear film, such as corneal topography, interferometry, tear meniscus measurement, evaporation rate, tear osmolarity and even aberrometry. Some are easily accessible to clinicians, while others remain in the field of clinical research. All of these tests provide a better understanding of the pathophysiology of the tear film. This review hopes to provide an overview of the existing tests and their role in evaluating the significance of the tear film in visual function.

Tear film analysis and evaluation of optical quality: A review of the literature

Dry eye is a complex multifactorial disease of the ocular surface and tears. It is associated with ocular surface symptoms and is one of the most common causes for ophthalmologic consultation. Despite their frequent use in clinical practice, the usual tests to evaluate dry eye and ocular surface disease-history of symptoms, tear break-up time (TBUT), Meibomian gland evaluation, corneal fluorescein staining, Schirmer test-have shown low reproducibility and reliability. In addition, subjective symptoms are often weakly or poorly correlated with objective signs. Since the tear film is the first system through which light must pass, the optical quality of the eye is highly dependent on the homogeneity of the tear film. Various investigative methods have been developed to evaluate both the structural and functional quality of the tear film, such as corneal topography, interferometry, tear meniscus measurement, evaporation rate, tear osmolarity and even aberrometry. Some are easily accessible to clinicians, while others remain in the field of clinical research. All of these tests provide a better understanding of the pathophysiology of the tear film. This review hopes to provide an overview of the existing tests and their role in evaluating the significance of the tear film in visual function.

Immediate effect of a tear enhancer and meibomian gland expression on the corneal surface and whole eye higher order aberrations

PURPOSE

To investigate changes in higher order ocular aberrations (HOA) induced by the administration of 0.15% sodium hyaluronate tear enhancer (TE) and meibomian gland expression (ME) on the tear film of normal subjects.

METHODS

HOA values were obtained from the corneal surface (CS) and whole eye (WE), using a corneal topographer and Shack-Hartmann aberrometer, from both eyes of 50 subjects (25 females, mean age±sd 32.5±11.0 years, and 25 males, 33.88±11.2 years) for two pupil sizes (3 and 6mm) in a dark environment. One drop of Blink Contacts™ (Abbott Medical Optics) was instilled into the right eye and HOA measurements repeated after 30s. After 1h, the meibomian glands of the left lower eyelid were gently squeezed and HOA measurements repeated after 30s.

RESULTS

There was no significant difference for CS and WE root mean square (RMS) HOAs between right and left eyes before (both pupil sizes) and after TE use or ME (3mm pupil). For 6mm pupil, TE use significantly reduced the WE RMS HOA (p<0.05, mean±sd) for Z40 (0.297±0.136 to 0.053±0.069), and Z55 (0.221±0.372 to 0.098±0.121) while ME significantly increased CS RMS HOA (p<0.05, mean±sd) for Z3-3 (0.799±1.178 to 1.302±1.991) and Z44 (0.594±1.184 to 0.988±1.463). In general, the change in HOA was significantly correlated with the initial value before TE use or ME (p<0.05).

CONCLUSION

There were no detectable differences between right and left eyes. For the 6mm pupil, the tear enhancer tended to improve optical performance of the WE and meibomian gland expression tended to reduce the optical performance at the CS.

Effects of tear film dynamics on quality of vision

The precorneal tear film is maintained by blinking and exhibits different phases in the tear cycle. The tear film serves as the most anterior surface of the eye and plays an important role as a first refractive component of the eye. Alterations in tear film dynamics may cause both vision-related and ocular surface-related symptoms. Although the optical quality associated with the tear film dynamics previously received little attention, objective measurements of optical quality using wavefront sensors have enabled us to quantify optical aberrations induced by the tear film. This has provided an objective method for assessing reduced optical quality in dry eye; thus, visual disturbances were included in the definition of dry eye disease in the 2007 Dry Eye Workshop report. In addition, sequential measurements of wavefront aberrations have provided us with valuable insights into the dynamic optical changes associated with tear film dynamics. This review will focus on the current knowledge of the mechanisms of wavefront variations that are caused by different aspects of tear film dynamics: specifically, quality, quantity and properties of the tear film, demonstrating the respective effects of dry eye, epiphora and instillation of eye drops on the quality of vision.

Blink: Characteristics, Controls, and Relation to Dry Eyes

Blink is a complex phenomenon that is profoundly affected by diverse endogenous and exogenous stimuli. It has been studied in the context of cognition, emotional, and psychological states, as an indicator of fatigue and sleepiness, particularly in the automobile and transportation industry, in visual tasking, and finally, as it relates to tear film stability and ocular surface health. The fact that it is highly variable and has input from so many sources makes it very difficult to study. In the present review, the behavior of blink in many of these systems is discussed, ultimately returning in each instance to a discussion of how these factors affect blink in the context of dry eyes. Blink is important to ocular surface health and to an individual's optimal functioning and quality of life. Disturbances in blink, as cause or effect, result in a breakdown of tear film stability, optical clarity, and visual function.

Objective and subjective assessing efficacy of a lubricating drop in eyes wearing silicone hydrogel contact lenses

Purpose

To investigate the effect of a lubricating drop on optical quality, tear film stability, and subjective symptoms in individuals wearing silicone hydrogel contact lens.

Methods

In this one-day, prospective single-center clinical study, Pre-lens Tear Deformation Time (PL-TDT), Root-Mean-Square (RMS) of Low Order Aberrations (LOA) and High Order Aberrations (HOA), individual twelve Zernike coefficients, and subjective symptoms were assessed in 43 volunteers (mean age 19.58 ± 1.63, 86 eyes) at 6 h after inserting the contact lens and then at 60 min after instilling a lubricating drop (Comfort drops, Avizor, Madrid-Spain).

Results

PL-TDT, LOA-RMS, and HOA-RMS values measured before drop instillation were not significantly different with those measured after drop. None of the Zernike coefficients were significantly different after instilling lubricating drop. Statistically significant decrement in both frequency and severity values in blurry vision, dryness, discomfort, burning, itching, foreign body sensation, excessive blinking, and lacrimation were seen after drop instillation (all P < 0.05).

Conclusion

Our results showed that although the lubricating drop did not improve the tear film stability and optical quality in the silicone hydrogel contact lens wearers, subjects experienced a subjective improvement.

Tear film lipids

Human meibomian gland secretions (MGS, or meibum) are formed from a complex mixture of lipids of different classes such as wax esters, cholesteryl esters, (O-acyl)-ω-hydroxy fatty acids (OAHFA) and their esters, acylglycerols, diacylated diols, free fatty acids, cholesterol, and a smaller amount of other polar and nonpolar lipids, whose chemical nature and the very presence in MGS have been a matter of intense debates. The purpose of this review is to discuss recent results that were obtained using different experimental techniques, estimate limitations of their usability, and discuss their biochemical, biophysical, and physiological implications. To create a lipid map of MGS and tears, the results obtained in the author's laboratory were integrated with available information on chemical composition of MGS and tears. The most informative approaches that are available today to researchers, such as HPLC-MS, GC-MS, and proton NMR, are discussed in details. A map of the meibomian lipidome (as it is seen in reverse phase liquid chromatography/mass spectrometry experiments) is presented. Directions of future efforts in the area are outlined.

Effects of diquafosol tetrasodium administration on visual function in short break-up time dry eye

PURPOSE

To investigate the effect of diquafosol tetrasodium on tear and visual function in short break-up time (sBUT) dry eye (DE).

METHODS

This interventional nonrandomized comparative study involved 11 eyes in 11 patients with sBUT DE (symptom-positive sBUT group) and 13 eyes in 13 volunteers with BUT values ≤5 s without DE symptoms (symptom-negative sBUT group). Tear function was assessed by measuring BUT and Schirmer values. Serial measurements were made of visual acuities (using a functional visual acuity measurement system) and higher-order aberrations (using a wavefront sensor). The parameters were compared before and 1 month after diquafosol tetrasodium instillation. Any changes in symptomatology after administration were also recorded.

RESULTS

After diquafosol tetrasodium administration, BUT values tended to increase in the symptom-positive sBUT group (P=0.07) and significantly increased in the symptom-negative sBUT group (P<0.05). LogMAR functional, minimal, and maximal visual acuities and higher-order aberrations significantly decreased after diquafosol tetrasodium administration in the symptom-positive sBUT group (P<0.05), while there were no significant changes in these values in the symptom-negative sBUT group (P>0.05). Diquafosol tetrasodium administration provided relief of DE symptoms in 75% of patients in the symptom-positive sBUT group.

CONCLUSIONS

Diquafosol tetrasodium appeared to improve tear film stability and visual function in sBUT DE.

Dry Eye Disease: Impact on Quality of Life and Vision

Dry eye disease (DED) is a growing public health concern causing ocular discomfort, fatigue and visual disturbance that interferes with quality of life (QoL), including aspects of physical, social, psychological functioning, daily activities and workplace productivity. This paper assesses the current understanding of the impact of DED on QoL and vision. The full impact of DED on a patient's QoL is not easily quantifiable, but several methods and techniques have been evaluated to measure the decreased quality of vision from DED, and a number of questionnaires have been developed to quantify the impact of DED on various aspects of patient QoL. We summarize available evidence on the impact of DED based on a review of published literature.

A two-week clinical evaluation of the safety of Systane Ultra in contact lens-wearing patients

Objective:

To evaluate the safety of Systane^® Ultra Lubricant Eye Drops (test solution) in contact lens wearers. A currently marketed contact lens rewetting drop was the control solution.

Participants:

This investigator- and patient-masked, single-site, randomized, and prospective study involved 45 successful contact lens wearers.

Methods:

Eligible subjects’ baseline biomicroscopy findings, visual acuity, and corneal staining score were recorded. Subjects received either the test or control solution with masked labeling. Subjects were instructed to instill their assigned solution in both eyes: 15 minutes prior to lens insertion, at least one drop during lens wear and another drop immediately following lens removal. After 14 days, biomicroscopy results, visual acuity, and corneal staining score were recorded.

Results:

No adverse events were documented for either the test or the control solution. For subjects using Systane^® Ultra, no statistically significant change was detected in visual acuity (= 0.7667) or corneal staining score (P = 1.000). For subjects using the control solution, the change in visual acuity (P = 0.0011, mean difference = 1.70 ± 3.22 standard deviation) was not clinically relevant and there was no significant change in corneal staining score (P = 0.5413).

Conclusions:

This clinical study provided evidence of safety and compatibility of Systane Ultra Lubricant Eye Drops in contact lens wearers.

Measurement of the time course of optical quality and visual deterioration during tear break-up

PURPOSE

To compare changes in optical quality and visual performance that accompany tear break-up (TBU) during blink suppression.

METHODS

A three-channel optical system was developed that simultaneously measured refractive aberrations (Shack-Hartmann aberrometer), 20/40 letter contrast sensitivity (CS), and TBU (retroillumination, RI). Ten wearers of silicone hydrogel contact lenses were asked to keep one eye open for approximately 18 seconds, while CS, wavefront aberrations, and RI images were collected. The wavefront was reconstructed by zonal methods, and image quality was quantified with a series of metrics including RMS fit error. Novel metrics for quantifying TBU over the contact lens surface were developed by quantifying the contrast of the RI image and by using Fourier descriptors of the first Purkinje (PJ) image shape.

RESULTS

There was a full range of TBU over the lens surface, with four subjects showing TBU across the corneal center and one subject with TBU in the inferior peripheral pupil. Among the four subjects with central corneal TBU, RMS fit error, RI contrast, and PJ Fourier descriptors showed high correlation with CS (r(2) range, 0.9187-0.9414, 0.6261-0.975, and 0.4917-0.8986, respectively). Some of the general optical-quality metrics such as blur strength, neural sharpness, and area of modulation transfer function (MTF) also showed that change correlated with CS loss.

CONCLUSIONS

Optical metrics of tear quality and retinal image quality are associated with the decline in vision that occurs with TBU. The evidence supports the hypothesis that blurry vision symptoms reported by contact lens wearers are caused by poor quality of the retinal image due to TBU.

Visual performance after reduced blinking in eyes with soft contact lenses or after LASIK

PURPOSE

To evaluate visual performance during concentrated visual work in patients wearing soft contact lenses or after LASIK.

METHODS

Thirty-one eyes of 17 patients who had worn soft contact lenses before LASIK were examined by the following tests immediately and 10 seconds after eye opening: 1) functional visual acuity, which is defined as visual acuity measured after prolonged eye opening without blinking; 2) surface regularity index (SRI) and surface asymmetry index (SAI) in corneal topography; and 3) higher order aberration measured with NIDEK OPD-Scan. Results were compared in the same patients before (with soft contact lenses and no eye surgery) and 1 month after LASIK (without soft contact lenses).

RESULTS

Functional visual acuity was significantly decreased 10 seconds after eye opening compared with immediately after eye opening, both with soft contact lenses and after LASIK, and decreased to a greater extent with soft contact lenses. The SRI and SAI were significantly increased 10 seconds after eye opening compared with immediately after eye opening, both with soft contact lenses and after LASIK, and increased to a greater extent with soft contact lenses. Higher order aberration was increased 10 seconds after eye opening with soft contact lenses, but not after LASIK.

CONCLUSIONS

Our results suggest that prolonged eye opening induces a decreased quality of vision in eyes of soft contact lens wearers and after LASIK. Under conditions in which blinking is restricted due to concentrated visual work, such as visual display terminal work, reading, and driving, visual performance may be more compromised with soft contact lens wear than after LASIK.

Binocular open-view Shack-Hartmann wavefront sensor with consecutive measurements of near triad and spherical aberration

We have developed a binocular open-view Shack-Hartmann wavefront sensor for measuring time variation of binocular accommodation, vergence, pupil sizes (i.e., the binocular near triad), and monochromatic aberrations. The device measures these values16 times per second for up to 1 min. Our purpose is to introduce the new instrument. We have confirmed the accuracy of the device. Refractions for a 4 mm pupil were accurate across the range of measurements of model eyes and normal human eyes. We measured binocular dynamics of accommodation, vergence, and spherical aberrations.

Patient-reported symptoms in dry dye disease

Clinically, dry eye has often been reported as a "symptom-based" disease, and definitions of dry eye based on symptoms have been used to define dry eye prevalence in population-based studies. Given this, patient-reported symptoms often do not correlate with diagnostic tests unless disease is severe or testing is tightly controlled. Progress in the understanding of dry eye symptoms has been made over the last 10 years; however, the link between symptoms and disease status, such as ocular surface damage or inflammation, remains elusive. Although several surveys for dry eye have been developed for screening or diagnosis, an accepted, validated survey capable of accurately monitoring changes with time or treatment is not available. Common symptoms, available surveys, and the associations between diagnostic tests and symptoms are reviewed.