Quality of Vision in Eyes With Epiphora Undergoing Lacrimal Passage Intubation

Higher Order Aberrations in Patients with Unilateral Nasolacrimal Duct Obstruction

PURPOSE

To compare corneal higher order aberrations (HOAs) in patients with epiphora caused by unilateral primary acquired nasolacrimal duct obstruction (PANDO) and their fellow eyes.

METHODS

A total of 122 eyes of 61 patients with unilateral PANDO were included. Affected eyes were named as group 1 and contralateral eyes as group 2. The Munk score and fluorescein dye disappearance test (FDDT) were assessed. Corneal topographic and HOAs measurements were taken by Sirius topography.

RESULTS

There were 47 female and 14 male patients. The mean keratometry was 43.84 ± 1.4 in group 1 and 43.96 ± 1.4 in group 2 (p = 0.73). The mean corneal topographic astigmatism was 0.81 ± 0.7 in group 1 and 0.78 ± 0.5 in group 2 (p = 0.57). The mean coma-like aberration was 0.19 ± 0.2 in group 1 and 0.10 ± 0.1 in group 2 (p = 0.03). The mean spherical-like aberration was 0.16 ± 0.1 in group 1 and 0.11 ± 0.1 in group 2 (p = 0.04). The mean total corneal HOA was 0.30 ± 0.5 in group 1 and 0.23 ± 0.2 in group 2 (p = 0.04). The mean Munk score was 3.47 ± 1.0 in group 1. There was a positive correlation between the Munk score and both coma-like aberration (r = 0.53, p = 0.003) and total corneal HOAs (r = 0.44, p = 0.010). The mean FDDT grade was 2.60 ± 0.1 in group 1. A positive correlation was observed between the FDDT grade and both coma-like aberration (r = 0.48, p = 0.001) and total corneal HOAs (r = 0.33, p = 0.001).

CONCLUSIONS

Epiphora in patients with PANDO can affect corneal HOAs. As patients' symptoms and tear pooling were increased as corneal HOA levels increased.

Efficacy of 3% diquafosol long-acting eye drops in dry eye patients treated for three months

PURPOSE

To investigate changes in the ocular surface and subjective symptoms during a three months administration of 3% diquafosol long-acting (DQL) eye drops.

STUDY DESIGN

Prospective observational study.

METHODS

DQL eye drops were administered as the sole treatment for all patients, including those in the group where DQL eye drops were newly prescribed (New DQL) and the group who switched from 3% diquafosol (DQS) eye drops (Switched DQL) in this prospective study. Each group underwent assessment of tear meniscus height (TMH), ocular surface disease index (OSDI), fluorescein break-up time (FBUT), fluorescein score, and Schirmer 1 test before DQL administration, at one month, and at three months. Changes in ocular surface scores and subjective symptoms at each time point were analyzed.

RESULTS

The study included a total of 63 eyes of 63 patients, with a mean age of 60.3 ±14.6 (SD). Among them, 29 patients (20 women) were in the New DQL group, and 34 patients (24 women) were in the Switched DQL group. Both the New DQL and Switched DQL groups showed significant improvements in TMH, OSDI, FBUT, Fluorescein Score, and Schirmer 1 test after three months of DQL eye drop administration.

CONCLUSION

DQL eye drops have the potential to improve ocular scores and subjective symptoms in patients with DE over a three months period, regardless of whether it is newly initiated or as a switch from DQS eye drops.

Comparative study of surgical outcomes regarding tear meniscus area and high-order aberrations between two different interventional methods for primary acquired nasolacrimal duct obstruction

PURPOSE

To compare endonasal dacryocystorhinostomy (EN-DCR) with sheath-guided dacryoendoscopic probing and bicanalicular intubation (SG-BCI) by evaluating tear meniscus area (TMA) and total high-order aberrations (HOAs) for primary acquired nasolacrimal duct obstruction (PANDO).

METHOD

We retrospectively reviewed 56 eyes of 42 patients (7 men, 35 women; age, 72.7±13.1 years) who underwent EN-DCR or SG-BCI for PANDO in Toyama University Hospital from February 2020 to June 2022. In the EN-DCR and SG-BCI groups, we measured the patency of the lacrimal passage, preoperative and postoperative TMA, and HOAs of the central 4 mm of the cornea using optical coherence tomography (AS-OCT), six months postoperatively.

RESULTS

There was a positive correlation between preoperative TMA and preoperative HOAs in all cases. Postoperative patency of lacrimal passage was 100% in the EN-DCR and 80.8% in the SG-BCI group. There was a significant difference in the number of passages between the two groups (p = 0.01). Preoperative TMA and HOAs showed a significant postoperative decrease in both groups (EN-DCR group: p<0.01, p<0.01, SG-BCI group: p<0.01, p=0.03, respectively). We then calculated the rate of change of preoperative and postoperative TMA and HOAs and compared them between the two groups. The rate of change was significantly higher in the EN-DCR group than that in the SG-BCI group (TMA, p=0.03; HOAs, p=0.02).

CONCLUSION

Although both EN-DCR and SG-BCI are effective for PANDO, our results suggest that EN-DCR is more effective in improving TMA and HOAs.

Complement activation products in tears of dry eye and meibomian gland dysfunction

Sixty-seven patients (38 woman; median age, 69 years) were enrolled to assess complement activation products (CAPs) in tear fluid with/without dry eye (DE) and with/without meibomian gland dysfunction (MGD). Patients were divided into four groups based on the presence/absence of DE and MGD: group DM had both DE and MGD, group DN had DE without MGD, group NM had MGD without DE, and group NN had neither DE nor MGD. The levels of C3a and C5a in the collected tears were analyzed using a cytometric bead array. The C3a concentrations in the DM, DN, NM, and NN groups were 2326 pg/ml, 1411 pg/ml, 1821 pg/ml, and 978 pg/ml, respectively. The C5a concentrations in the DM, DN, NM, and NN groups were 24.7 pg/ml, 15.3 pg/ml, 24.1 pg/ml, and 12.9 pg/ml, respectively. The concentrations of C3a and C5a in the DM and NM groups were significantly higher than in the NN group (P < 0.05 for both comparisons). The CAPs in the tear fluid in MGD and DE increased. Local dysregulation of the innate immune system can be associated with the development of MGD and DE in elderly patients.

Recovery of the Ratio of Closure Time during Blink Time in Lacrimal Passage Intubation

(1) Background: We aim to find a novel blink parameter in nasolacrimal duct obstruction (NDO) patients and analyze parameters that could reflect subjective symptoms and objective indicators at the same time through a blink dynamic analysis. (2) Methods A retrospective study was conducted with 34 patients (48 eyes) who underwent lacrimal passage intubation (LPI) and 24 control groups (48 eyes). All patients' blink patterns were measured using an ocular surface interferometer before and after LPI, including total blink (TB) and partial blink (PB) and the blink indices blink time (BT), lid closing time (LCT), closure time (CT), lid opening time (LOT), interblink time (IBT), closing speed (CS) and opening speed (OS). The tear meniscus height (TMH) was measured, and the questionnaire "Epiphora Patient's Quality of Life (E-QOL)," which includes daily activity restriction as well as static and dynamic activities, was completed. (3) Results: Compared to CT and the ratio of CT during BT (CT/BT) in control (89.4 ± 20.0 msec, 13.16%), those in NDOs were longer (140.3 ± 92.0 msec, 20.20%) and were also related to TMH. After LPI, CT and CT/BT were recovered to 85.4 ± 22.07 msec, 13.29% (p < 0.001). CT and CT/BT showed a positive correlation with the E-QOL questionnaire score, particularly with dynamic activities. (4) Conclusions: CT and CT/BT, which are objective indicators associated with subjective symptoms of patients, are considered new blink indices for the evaluation of NDO patients with Munk's score.

Predicting Residual Astigmatism in Cataract Surgery

The purpose of this review is to evaluate the prediction of postoperative residual astigmatism and to determine the best prediction method for astigmatism correction. In recent findings for residual astigmatism in non-toric monofocal intraocular lens (IOL) implanted eyes, vector analysis can be used to correctly evaluate residual astigmatism by decomposing it. In predicting residual astigmatism, the with-the-rule (WTR) and against-the-rule (ATR) astigmatism components can now be almost predicted. This may be due to advances in inspection equipment and surgical technique. However, there are still issues with the oblique astigmatism component. In addition, corneal astigmatism is the most important predictor of postoperative residual astigmatism, and other predictors, such as refractive astigmatism, age, and lens thickness, have also been mentioned. However, all but corneal astigmatism are questionable because of the possibility of confounding variables. Total corneal astigmatism is more accurate in predicting residual astigmatism than anterior corneal astigmatism. Several predictions of residual astigmatism have been reported, but complete prediction has not been possible. Further research is needed, especially in predicting oblique astigmatism. However, I emphasize that the accuracy of predicting WTR and ATR astigmatism has improved considerably and can be predicted using regression equations with total corneal astigmatism.

Association between tear meniscus dimensions and higher-order aberrations in patients with surgically treated lacrimal passage obstruction

PURPOSE

To analyze the relationship between tear meniscus dimensions and higher-order aberrations (HOAs) in patients with lacrimal passage obstruction using anterior segment optical coherence tomography (AS-OCT).

METHODS

This study was a retrospective observational study of 71 eyes of 49 patients with lacrimal passage obstruction. These patients received sheath-guided dacryoendoscopic probing and bicanalicular intubation (SG-BCI) at Toyama University Hospital between August 2020 and October 2021. Using AS-OCT, tear meniscus height (TMH), tear meniscus area (TMA), and total corneal HOAs values were measured before and after surgery.

RESULTS

Surgical success was achieved in 69 eyes (97.1%). At the final observation, 62 eyes showed lacrimal patency (89.8%). The preoperative TMH, TMA, and HOAs values were 1.55 ± 0.96 mm, 0.11 ± 0.14 mm², and 0.37 ± 0.27 µm, respectively, and the final postoperative TMH, TMA, and HOAs values were 0.97 ± 0.74 mm (p < 0.0001), 0.06 ± 0.11 mm² (p = 0.02), and 0.29 ± 0.16 µm (p = 0.001), respectively. The results showed a significant improvement. The changes in HOAs before and after surgery were positively correlated with the changes in TMH (r = 0.3476, p = 0.0241) and TMA (r = 0.3653, p = 0.0174).

CONCLUSION

SG-BCI for lacrimal passage obstruction resulted in a significant decrease in measured HOAs. The decrease in HOAs was correlated with decreases in tear meniscus dimensions.

Prevalence and Risk Factors of Dry Eye Symptoms after Successful Dacryocystorhinostomy for Patients with Lacrimal Passage Obstruction

PURPOSE

To investigate the prevalence of dry eye symptoms after successful dacryocystorhinostomy and explore the potential risk factors. Methods: This cross-sectional study included 565 patients with lacrimal passage obstruction (LPO) who underwent external dacryocystorhinostomy. Ocular Surface Disease Index (OSDI) total score of 13 or more was regarded as presence of dry eye symptoms. OSDI total score greater than 22 combined with self-reported dry eye was defined as symptomatic dry eye. Logistic regression and linear regression were used to examine the associations between OSDI scores and its potentially predictive factors. Results: Of the 565 patients, 344 completed the questionnaire, among which 101(29.4%) patients presented with dry eye symptoms, including 53(15.4%) mild, 14(4.1%) moderate and 34(9.9%) severe, and 48(14.0%) patients can be defined as symptomatic dry eye. Univariate logistic regression revealed that age, educational levels, income levels, and hypertension were significantly correlated with the presence of dry eye symptoms (P < 0.05). After multivariate adjustment, lower income levels were found significantly associated with dry eye symptoms (P < 0.05). Univariate linear regression demonstrated that age, lower educational levels, surgery history, and hypertension were significantly associated with OSDI total score (P = 0.037, 0.012, 0.022, 0.029 respectively). Multivariate stepwise linear regression manifested that educational levels and the surgery history influenced the OSDI total score mostly (P = 0.021, 0.036 respectively). Conclusions: Dry eye problem of LPO patients after successful dacryocystorhinostomy cannot be ignored. In the preoperative evaluation, we should pay special attention to the elderly patients with lower educational levels, lower income levels or systemic diseases.

Tear protein analysis in patients with primary acquired nasolacrimal duct obstruction treated with lacrimal passage intubation

PURPOSE

The pathophysiology of nasolacrimal duct obstruction (NLDO) may involve quantitative as well as qualitative changes in tears. We measured tear protein concentrations in patients with primary acquired NLDO and compared them with the tear proteins in healthy individuals and patients with dry eye disease.

STUDY DESIGN

Case-control study.

METHODS

Twenty-four patients diagnosed with primary acquired NLDO who underwent endoscopic lacrimal passage intubation were included in the study. Tear fluid was collected with Schirmer's test strips three times: before intubation, after intubation while the nasolacrimal tube was in place, and after extubation. At the same time, 24 age-matched normal controls and 24 patients with dry eye were selected from subjects whose tears were collected during the same study period. We measured the following components of tear fluid: total protein, lactoferrin, albumin, and interleukin 6 (IL-6) levels.

RESULTS

Total proteins and albumin levels in tears of the NLDO group were significantly lower than those of the control group (P < 0.001 and P = 0.014, respectively, Mann-Whitney U test). Total proteins, albumin, and lactoferrin levels were significantly increased after extubation of nasolacrimal tube (P < 0.001, P = 0.004, and P = 0.029, respectively, Wilcoxon matched-pairs signed-rank test). There were no statistically significant differences in total protein, albumin, lactoferrin and IL-6 levels between patients with NLDO after lacrimal passage extubation and controls.

CONCLUSIONS

Our study shows distinct differences in protein composition of tear fluid in NLDO eyes and demonstrates that these can be normalized by nasolacrimal tube placement.

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.

Assessment of conjunctival flora in eyes with lacrimal passage obstruction before and after successful dacryoendoscopic recanalisation

BACKGROUND

To investigate conjunctival bacterial flora in eyes with lacrimal passage obstruction before and after dacryoendoscopic recanalisation with lacrimal tube intubation.

METHODS

One-hundred fifty eyes with lacrimal passage obstruction that were successfully treated by dacryoendoscopic recanalisation were enrolled. Conjunctival sampling was done for each eye before and 4 months after surgery. The lower fornix was rubbed by a sterile cotton swab, and the collected samples were cultured with several agar plates. Colonies were differentiated and enumerated by standard bacteriological laboratory techniques.

RESULTS

Positive bacterial growth was detected in 42.0% of all the samples before surgery, and the positivity rate significantly decreased to 26.0% after surgery (p=0.0051). The number of strains detected also decreased from 20 before surgery to 9 after surgery, especially pathogenic microorganisms decreased. In addition, drug-resistant bacteria such as penicillin-resistant Streptococcus pneumoniae and methicillin-resistant Staphylococcus aureus were detected in nine eyes before surgery but were detected only in one eye after surgery. Coagulase-negative Staphylococci and Corynebacterium spp., which are common in normal conjunctival flora, accounted for 46.5% of all the isolates before surgery and 80.9% after surgery, showing a significant increase in the rate after surgery (p<0.0001).

CONCLUSIONS

This study showed that physiological recanalisation of lacrimal passage after dacryoendoscopic surgery significantly decreased the culture positivity rate of conjunctival sac and the number of microorganism strains detected. It also decreased the number of potentially pathogenic and drug-resistant bacteria and increased the percentages of indigenous bacteria, causing the normalisation of conjunctival flora.

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.

Changes of Visual Symptoms and Functions in Patients with and without Dry Eye after Lacrimal Passage Obstruction Treatment

Purpose: To determine the quality of life (QOL) and quality of vision (QOV) of patients who developed and did not develop dry eye disease (DED) after nasolacrimal duct obstruction (NLDO) treatment. Methods: This was a retrospective nonrandomized observational study of 91 patients diagnosed with unilateral NLDO. The subjects underwent lacrimal stent insertion, and the stent was removed after 10-12 weeks. The QOL and QOV of the patients were examined preoperatively and at 6 months after the stent was removed. The postoperative outcomes were assessed subjectively with the Glasgow Benefit Inventory (GBI) questionnaire and an ocular specific questionnaire of 6 symptoms. The best-corrected visual acuity, functional visual acuity, and dry eye scores were also determined. Results: Of the 91 eyes, 19 eyes (20.9%) were diagnosed with DED (D group) and 72 were not (N group). Five of the 6 symptoms improved in the N group, while only 3 symptoms improved in the D group without blurred vision. For the GBI questionnaire, the social support and physical health scores were significantly higher in the N group than in the D group. The functional visual acuity improved significantly in the N group but not significantly in the D group. Conclusions: Patients who develop DED after treatments for NLDO may not have an improvement of their QOL or QOV. Therefore, careful dry eye assessments are important before treatments for NLDO.

Feasibility of Strip Meniscometry for Tear Volume Evaluation in Lacrimal Passage Obstruction

Strip meniscometry tube (SMTube) is useful for assessing tear volume in dry eye disease. We performed an in vitro and a clinical study to examine whether the SMTube can also be used to evaluate tear quantity in lacrimal passage obstruction (LPO). In vitro experiments showed that the SMTube value and the amount of water absorption were significantly correlated (R² = 0.816, p = 0.0008), but the measured value peaked when 4 μL was absorbed. In the clinical study, 12 eyes of 9 LPO patients and 17 eyes of 17 healthy control subjects were included. The patients’ SMTube values were significantly higher than those of the control subjects (p < 0.05). The SMTube value significantly decreased after silicon tube intubation (p < 0.05). Tear meniscus height (TMH) and area (TMA), measured by anterior segment optical coherence tomography, exhibited a significant positive correlation with the SMTube value (TMH, p < 0.001, R² = 0.396; TMA, p < 0.001, R² = 0.366). Moreover, the SMTube value significantly correlated positively with the subjective symptom of epiphora (p = 0.012, R² = 0.255). Thus, SMTube was useful for evaluating the tear volume and therapeutic effects in patients with LPO.

Lacrimal drainage function after cheese wiring of lacrimal passage intubation

PURPOSE

To investigate how cheese wiring affects lacrimal drainage function by quantitative assessment of tear function and punctal dimensions.

METHODS

Patients who underwent lacrimal passage intubation between January 2017 and September 2018 were enrolled prospectively. Among these patients, those with postoperative cheese wiring who received lacrimal passage intubation in one eye met the criteria for further investigation. The subjective symptoms of epiphora, dimensions of puncta, lower tear meniscus, and tear clearance were assessed postoperatively in both the involved eye and untreated contralateral eye. Punctum dimensions were analysed using the digital slit-lamp image. Tear meniscus and tear clearance were assessed by anterior segment optical coherence tomography.

RESULTS

Postoperative cheese wiring was observed in 68 of 314 eyes. Among these cases, 36 patients (age 70.5 ± 11.7 years) had cheese wiring only in one eye: with the involvement of both puncta in 15 patients (group A) and only the lower punctum in 21 patients (group B). There was no patient with the involvement of only the upper punctum. While tear function of the involved eyes in group B did not differ from that of the untreated eye, it was significantly decreased in group A compared with that in untreated control eyes (p < 0.05). The tear clearance rate correlated significantly with the upper punctum dimensions (p < 0.05), but not with the lower punctum.

CONCLUSION

Analysis of cheese wiring after lacrimal passage intubation with tear function demonstrated that the integrity of the puncta and the canaliculus is important for lacrimal drainage.

Surgical Factors Affecting Changes in Ocular Surface Dynamics in the Early Postoperative Period After 25-Gauge Vitrectomy

OBJECTIVES

Because vitrectomy-associated postoperative ocular surface changes are not well known, we evaluated such changes before and after vitrectomy in eyes with posterior segment diseases and investigated their associations with patients' characteristics and surgical procedures.

METHODS

Thirty-five eyes of 32 consecutive patients (16 women; average age 66.6±11.1 years) were included in this prospective, noncomparative case series from tertiary care university hospital. Contact lens wearers and patients with history of ocular surgery or regular use of topical eyedrops were excluded. Patients had undergone primary 25-gauge vitrectomy at Osaka University Hospital in Japan between July and December 2016. Tear break-up time (TBUT), corneal and conjunctival fluorescein staining score (FSS), and tear meniscus height (TMH) were evaluated before, 1 week after, and 1 month after vitrectomy.

RESULTS

Conjunctival FSS and TMH were significantly higher at 1 week after vitrectomy than preoperatively. However, they decreased significantly 1 month after. Changes in TBUT and corneal FSS showed a similar course at 1 week, but this was not statistically significant. Multiple linear regression analysis showed no significant correlation between significantly increased ocular parameters and patients' characteristics. By contrast, surgical time and combined cataract surgery significantly contributed to increased and decreased conjunctival FSS, respectively (P=0.011 and 0.033, respectively). Sclerotomy site suturing significantly contributed to increased TMH (P=0.025).

CONCLUSIONS

We showed associations between ocular surface changes and specific surgical procedures. Caution should be exercised to minimize the effect of surgical procedures on the ocular surface during vitrectomy.

Evaluation of the tear clearance rate by dacryoscintigraphy in patients with obstructive meibomian gland dysfunction

PURPOSE

To measure tear clearance values in patients with meibomian gland dysfunction (MGD) with a dynamic nuclear medicine method, namely, dacryoscintigraphy (DSCI).

METHODS

Twenty-four MGD patients and 24 healthy volunteers were examined. During DSCI one drop of a solution with 100 MBq/mL^99mTc sodium pertechnetate was instilled with a micropipette into the lacrimal lake of both eyes. Measurements were performed according to a dynamic data acquisition protocol, which resulted in summed DSCI images. Data were also evaluated separately in special regions of interest (ROI), and consecutive time activity curves were created. Tear clearance (T½) values were calculated based on the activity curves. In addition, tear osmolarity measurements, tear breakup time (tBUT), and Schirmer I (ST_I) tests were performed prior to DSCI examination.

RESULTS

The T½ values were 29.91 ± 11.61 min in MGD patients and 6.26 ± 1.5 min in healthy controls. Tear osmolarity parameters were 308 ± 9.41 mOsm/L and 288.9 ± 6.4 mOsm/L, tBUT values were 5.54 ± 2.73 s and 11.4 ± 2.7 s, while the ST_I test values were 6.17 ± 2.78 mm and 13.58 ± 3.8 mm, respectively. The differences were significant (p < 0.01) in all cases.

CONCLUSIONS

Although the MGD patients' lacrimal drainage systems were patent their tear clearance values were significantly higher than those of healthy volunteers, which may be caused by decreased drainage of tears from the eyes towards the nasal cavity. The understanding of new features regarding the altered physico-chemical characteristics of MGD tears has been augmented by the results of this study.

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.