Purpose: To investigate the correlation between the changes in the ocular surface temperature (OST) and tear film stability over soft contact lenses (SCLs). Methods: We enrolled 20 eyes of 20 normal SCL wearers (20 men; 24.4 ± 4.1 years). We used four different daily disposable SCLs: one silicone hydrogel lens (delefilcon A) and three hydrogel lenses (etafilcon A with polyvinylpyrrolidone [PVP], etafilcon A, and polymacon). OST was measured every second during 10 seconds without blinking. We defined the difference in the OST from 0 to 10 seconds as ΔOST. To evaluate tear film stability, we measured noninvasive tear break-up time (NIBUT) and tear interference patterns on the contact lenses (TIPCL) using tear film interferometry. The parameters were measured before and 15 minutes after wearing each SCL. Results: ΔOST was correlated significantly with NIBUT without (r = 0.411, P < 0.01) and with SCL (r = 0.642, P < 0.01). TIPCL grade was correlated significantly with ΔOST over SCLs (r = −0.636, P < 0.01). ΔOST was significantly smaller with silicone hydrogel delefilcon A than hydrogel etafilcon A and polymacon lenses (P < 0.05 and P < 0.01, respectively). Delefilcon A and etafilcon A with PVP lenses had significantly smaller NIBUT than etafilcon A (P < 0.05 for both comparisons). TIPCL grade of delefilcon A lens was significantly smaller than those of etafilcon A and polymacon (P < 0.01 for both comparisons). Conclusions: The changes in OST over SCLs are related to tear film stability. Measurements of OST can be used to evaluate tear film stability for SCL wearers.

Measuring the ocular blood flow in neonates may clarify the relationships between eye diseases and ocular circulation abnormalities. However, no method for noninvasively measuring ocular circulation in neonates is established. We used laser speckle flowgraphy (LSFG) modified for neonates to measure their ocular circulation and investigated whether this method is reproducible. During their normal sleep, we studied 16 subjects (adjusted age of 34–48 weeks) whose blood flow could be measured three consecutive times. While the subjects slept in the supine position, three mean blur rate (MBR) values of the optic nerve head (ONH) were obtained: the MBR-A (mean of all values), MBR-V (vessel mean), and MBR-T (tissue mean), and nine blood flow pulse waveform parameters in the ONH were examined. We analyzed the coefficient of variation (COV) and the intraclass correlation coefficient (ICC) for each parameter. The COVs of the MBR values were all ≤10%. The ICCs of the MBR values were all >0.8. Good COVs were observed for the blowout score, blowout time, rising rate, falling rate, and acceleration time index. Although the measurement of ocular circulation in the neonates was difficult, our results exhibited reproducibility, suggesting that this method could be used in clinical research.

Purpose. To investigate the association among the ocular surface temperature (OST), tear film stability, functional visual acuity (FVA), and blink rate in patients after cataract surgery. Methods. We recruited 98 eyes of 69 patients (mean age, 73.7 ± 5.2 years) 1 month after phacoemulsification with implantation of acrylic intraocular lenses and assessed slit-lamp microscopy, corrected distance VA, FVA, noninvasive tear breakup time (NIBUT), and OST. We defined the changes in the OST from 0 to 10 seconds after eye opening as the ΔOST. We measured the FVA and blink rate using the FVA measurement system. We divided the patients into two groups based on tear film stability: stable tear film (NIBUT, >5.0 seconds) and unstable tear film (NIBUT, ≤5.0 seconds). We evaluated the differences between the two groups and the association between the blink rate and other clinical parameters. Results. The unstable tear film group (56 eyes) had significantly (p<0.0001, unpaired t-test) shorter NIBUTs than the stable tear film group (42 eyes). The ΔOSTs and blink rates were significantly (p<0.0001) higher in the unstable tear film group than in the stable group. Linear single regression analysis showed that the ΔOST (r = −0.430, p<0.0001), NIBUT (r = −0.392, p<0.0001), and gender (r = −0.370, p=0.0002) were correlated significantly with the blink rate. Multiple regression analysis showed that the ΔOST independently contributed to the blink rate. Conclusions. The frequency of blinks is associated with tear film stability in patients after cataract surgery. The blink rate may be useful for evaluating the tear film stability in clinical practice. The ΔOST should be an important contributing factor to the blink rate. [This trial is registered with UMIN000026970].

Purpose: Prelens tear film stability of soft contact lens (SCL) play an important role for contact lens discomfort. In this study, we investigated the association between two types of noninvasive methods and evaluated the tear film stability with SCL using the methods. Patients and Methods: In experiment 1, images of ring mire were recorded with a keratograph after focusing the pigment located at the front or back of the SCL. Interferometry and videokeratoscopy were used for the assessment of tear film stability in the right eye of 10 women, with two different cosmetic daily disposable SCLs: polymacon and etafilcon A with polyvinylpyrrolidone. Time to first distortion by noninvasive keratograph break up time (NIKBUT-first) was compared to noninvasive interferometry break up time (NIBUT). In experiment 2, ten normal females wore two different daily disposable SCLs: samfilcon A and narafilcon A. NIKBUT-first and NIBUT were compared between the lenses after 8 hours of SCL wearing. Results: In experiment 1, NIBUT-first without SCL was significantly correlated to NIBUT without SCL (r=0.445, P=0.0488, Pearson’s correlation coefficients). However, NIKBUT-first with SCL was not significantly correlated with NIBUT with SCL. In experiment 2, although NIKBUT-first was not significantly different between SCLs, samfilcon A had significantly longer NIBUT than narafilcon A (P=0.0315, paired t-test). Conclusion: NIKBUT-first with SCL could be related to tear film stability between the lens and the corneal surface, but not to prelens tear film stability. NIIBUT could be a suitable method to evaluate prelens tear stability.

Purpose: To determine a correlation between temperature and blood flow in the ocular anterior segment, and their effects on corneal temperature. Methods: In experiment 1, we recruited 40 eyes and measured the temperature and blood flow in the ocular anterior-segment (upper/lower eyelid skin, palpebral and bulbar conjunctiva, and cornea) before and after application of warm compresses. In experiment 2, we recruited 20 eyes and measured the same tissues before and during stimulation using water and capsaicin solution in the oral cavity. Results: In experiment 1, the temperatures of the upper/lower eyelid skin and cornea increased significantly until 15 min after the application of the warm compress; the temperatures of the palpebral and bulbar conjunctiva increased significantly until 10 min. The blood flow in the upper/lower eyelid skin and bulbar conjunctiva increased significantly until 10 min, and that of the palpebral conjunctiva increased significantly until 15 min. In experiment 2, the temperatures were correlated significantly with the blood flow in the upper and lower eyelid skin and palpebral and bulbar conjunctiva. The temperature of all locations and palpebral conjunctival blood flow contributed independently to the corneal temperature. Conclusions: In the ocular anterior segment, the temperature and blood flow were correlated significantly, and contributed to the corneal temperature.