Pupil size of myopes under different mesopic conditions and its influencing factors / 中华实验眼科杂志

Objective:To explore the pupil size distribution of the Chinese myopic population under different mesopic conditions, and to analyze the possible influencing factors.Methods:A cross-sectional study was conducted.Two hundred and fourteen myopic patients (428 eyes) who underwent refractive surgery in Tianjin Eye Hospital from December 2018 to April 2019 were randomly selected.The patients were 17 to 45 years old, with an average age of (22.62±4.88) years old.The patients were divided into astigmatism <-1.5 D group (372 eyes) and astigmatism ≥-1.5 D group (56 eyes) according to their astigmatism measurements.The low mesopic pupil size (LMPS) (0.2 lx) was measured with the infrared Colvard pupillometer, and the high mesopic pupil size (HMPS) (6-12 lx) was obtained through the anterior Pentacam segment analyzer.The pupil size was compared between both eyes, different sexes and different astigmatism measurements.The relationship between pupil size and possible influencing factors, such as age, sex, spherical equivalent, spherical diopter, cylinder diopter, axis, mean keratometry(Km), and central cornea thickness was analyzed.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Tianjin Eye Hospital (No.201912). Written informed consent was obtained from each subject or their guardians.Results:The pupil sizes measured by the Colvard pupillometer and Pentacam were (6.806±0.776)mm and (3.312±0.540)mm, respectively.The pupil size of male subjects was (6.692±0.754)mm, which was larger than (6.668±0.792)mm of females, showing a statistically significant difference ( t=2.935, P=0.004). Under the high mesopic condition, the pupil size of astigmatism ≥-1.5 D group was lower than that of astigmatism <-1.5 D group, with a statistically significant difference ( t=2.611, P=0.009). Under the low mesopic condition, pupil size was negatively correlated with age and Km ( r=-0.213, -0.210; both at P<0.001). Under the high mesopic condition, pupil size was weakly positively correlated with cylinder power ( r=0.124, P=0.010) and was weakly negatively correlated with Km ( r=-0.142, P=0.003). The multiple linear regression analysis revealed that the LMPS=0.659×HMPS-0.019×age-0.084×Km+ 8.662.About 28% of pupil size under low mesopic conditions could be predicted by Pentacam.LMPS of ≤7 mm could be better predicted when the results were below 3.6 mm. Conclusions:Age and corneal curvature are influencing factors of mesopic pupil size.Older people with steep curvature have a smaller pupil.At high mesopic conditions, astigmatism affects pupil size.Pentacam measurements can predict LMPS to some degree but are not a substitute for dark-adapted pupil diameter.

Mesopic Pupillometry in Pre-LASIK Patients by a Placido-Disc Topographer and Hartmann-Shack Aberrometer

@#Introduction: Precise pupillometry is crucial to determine ablation optical zone (OZ) size selection in LASIK. Significant difference in the selection induces unwanted postoperative night visual disturbance. Placido-disc topographer and Hartmann-Shack aberrometer are commonly used in LASIK preoperative assessment. However, little is known on the precision and agreement of these devices in pupillometry. Hence, this study aimed to evaluate the precision (repeatability and reproducibility) and inter-device agreement of a Placido-disc topographer and Hartmann-Shack aberrometer in measuring mesopic pupil size in pre-LASIK patients. Methods: Mesopic pupillometry on 38 pre-LASIK patients were performed using both devices by two masked operators, on two separate sessions. Intra-session repeatability, inter-operator reproducibility and inter-device agreement were analysed. A disagreement value of ±0.5 mm and 95% limits of agreement (LoA) were determined. Results: Hartmann-Shack aberrometer demonstrated higher repeatability and reproducibility than Placido-disc topographer in mesopic pupillometry. Ninety-seven percent and all of Hartmann-Shack wavefront aberrometer pupillometry were within ±0.5 mm in repeated sessions and between the operators, respectively. The mesopic pupil size obtained from Placido-disc topographer was significantly larger than Hartmann-Shack aberrometer results (P = 0.02). The agreement between devices was low (LoA > ±1 mm) and only 53% of Placido-disc topographer pupillometry were within ±0.5 mm of Hartmann-Shack aberrometer pupillometry. Conclusion: Hartmann-Shack aberrometer has higher precision within sessions and between operators, and it provides smaller mesopic pupillometry than Placido-disc topographer. Precise mesopic pupillometry could assist refractive surgeons in choosing a correct ablation OZ size during LASIK surgery to improve postoperative outcome.

Assessment of Pupil Diameters in Pseudoexfoliation Syndrome under Scotopic, Mesopic, Photopic and Dynamic Conditions Using Infrared Pupillometer (Assessment of Pupil Diameters in Pseudoexfoliation Syndrome).

Aim: Our study aims to assess the mean pupil size under scotopic, mesopic, photopic and dynamic conditions in patients with PXS. Methodology: This study was performed in Ophthalmology Clinic at İstanbul Bakırköy Dr.Sadi Konuk Training and Research Hospital. Fourty-six patients with PXS and 46 age and sex matched controls were included in the prospective study. The subjects were allowed at least 3 minute to adapt to the lighting condition in the room. Pupil diameters were measured with infrared (IR) pupillometer integrated within CSO Sirius Corneal Topographer (Costruzione Strumenti Oftalmici S.r.l,Italy ) by the same examiner. The measurements were taken in scotopic, mesopic, photopic and dynamic conditions. Statistical analyses were evaluated. Results: Mean pupil diameter were significantly lower in the PXS group than control group for all measurements. Scotopic and mesopic pupil size were significantly lower in the PXS group than control group (p=0.0001). Also photopic and dynamic pupil size were significantly lower in the PXS group than control group (p=0.014, p=0.013). Conclusion: The results suggest that pupillary light response in patients with PXS significantly was affected not only in scotopic and mesopic conditions but also in photopic and dynamic conditions.

Comparison of Intraocular Straylight in Patients with Clear and Photochromic Intraocular Lenses

PURPOSE: To compare visual acuity and intraocular straylight after implantation of clear and photochromic intraocular lenses (IOLs) in a mesopic lighting condition. METHODS: Clear IOLs were implanted in 95 eyes of 72 patients (clear IOL group), and photochromic IOLs were implanted in 22 eyes of 16 patients (photochromic IOL group). Best-corrected visual acuity (BCVA) was measured indoors before surgery and 1 month after surgery. Straylight values were measured indoors before surgery and 1 and 2 months after surgery using the C-quant straylight meter (Oculus GmbH, Wetzlar, Germany). RESULTS: There were no significant differences between the 2 groups in BCVA at 1 month postoperatively (p = 0.587). Mean straylight values of clear and photochromic IOL groups were 2.76 +/- 1.89 log (s) and 2.88 +/- 2.04 log (s) preoperatively, 1.39 +/- 0.84 log (s) and 1.32 +/- 0.26 log (s) at 1 month postoperatively, and 1.43 +/- 0.92 log (s) and 1.45 +/- 0.50 log (s) at 2 months postoperatively. There were no significant differences between the 2 groups in indoor straylight values (p = 0.778, 0.709, 0.929, before surgery, 1 and 2 months after surgery respectively). Repeated-measure analysis of straylight values also showed no significant difference between the 2 groups (p > 0.05). CONCLUSIONS: There were no significant differences in BCVA and straylight values between clear and photochromic IOL groups under a mesopic light condition. Therefore, photochromic IOL could be suitable choice for cataract patients who spend significant time under mesopic conditions.

A Study of Mesopic Vision and Glare in Normal Subjects and Post-LASIK Patients Using Mesoptometer

PURPOSE: To evaluate of the mesopic vision and glare in normal subjects and post-LASIK patients by using mesoptometer. METHODS: One hundred sixty eyes of eighty subjects with normal vision and no ocular disease were divided into four groups. Each twenty subjects were followed up for more than 3 months and the authors tested the mesopic vision and glare disability with Mesotest II. The authors also measured eighty eyes of forty patients by same means depending on pupil size and high order root mean square (RMS) values before LASIK surgery in 1st and 3rd months postoperatively and compared with data of normal subjects. RESULTS: The mesopic vision and glare disability at 1: 5 contrast level were extremly reduced in the group over 60 age old but there was no statistical significance. In post-LASIK patients, mesopic vision and glare disability were significantly reduced in 1st month after surgery. However the values returned nearly to preoperative figures in 3rd month. Patients with large pupil and high order RMS values reduced more in mesopic vision and glare disability but there was not statistical significance. CONCLUSIONS: The mesopic vision and glare disability were reduced in older age group and they were reduced in the patients with large pupils and high order RMS values in the early postoperative period after LASIK.

Contrast Sensitivity Function of Sound Eye after Occlusion Therapy in the Amblyopic Children

To verify the changes of mesopic and photopic contrast sensitivity function of sound eye whose visual acuity was kept the same after occlusion therapy in the amblyopic children. Fourteen sound eyes of amblyopic children (mean; 7.67 years; S.D., 1.50 years) who kept their visual acuity the same after the occlusion therapy were tested. The children had 6 hours of part-time patch therapy for 3 months prior to this examination. Among 14 amblyopic children, 8 were anisometric and 6 were strabismic amblyopes. Using the visual capacity analyzer which measures the minimal contrast level at from low to high spatial frequencies, the contrast sensitivity of sound eye was measured, under both photopic and mesopic condition, before and after 3 months of occlusion therapy. Comparing the contrast sensitivity of sound eye after the occlusion therapy to that before the occlusion, there was no statistical difference in photopic condition. When it comes to mesopic condition, the contrast sensitivity decreased at the intermediate spatial frequency level (3-13 c.p.d, p=0.028) after the occlusion therapy. The occlusion caused statistically significant decrease in mesopic contrast sensitivity, when the visual acuity was not changed after the occlusion therapy. It may indicate that mesopic contrast sensitivity can be considered as a useful tool for early detection of hidden occlusion amblyopia.

A Comparative Study for Mesopic Contrast Sensitivity between Keratectomy(PRK) and Laser in Situ Keratomileusis(LASIK)

PURPOSE: To compare the effect on visual performance of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) with mesopic contrast sensitivity using CSV-1000S in excimer laser refractive surgery using the broad beam type and manual microkeratome. METHODS: Postoperative visual performance for 40 eyes undergoing PRK and 40 eyes undergoing LASIK was compared with mesopic contrast sensitivity at 1, 3, and 6 months postoperatively using the CSV 1000 (VectorVision, Ohio, USA). Eyes were divided into two groups: less than 6.0 D and over 6.25 D. Mesopic contrast sensitivity was performed with the patient's uncorrected-visual acuity of 20/20 or better under photopic condition. RESULTS: Under mesopic conditions a significant decrease in contrast sensitivity for the postoperative PRK and LASIK group was obtained at all spatial frequencies compared to the preoperative baseline (p0.05). CONCLUSIONS: In the broad beam excimer laser, in cases of myopia with below 6.0 D, PRK seemed to have a more significant effect on mesopic contrast sensitivity than LASIK using manual microkeratome at postoperative 6 months.

Mesopic Contrast Sensitivity Functions in Amblyopic Children

This study both measured and compared the mesopic contrast sensitivity function and the visual acuity in both normal and amblyopic eyes from amblyopic children using an ACV (visual acuity analyzer). Twenty one amblyopic children (mean age, 8.48 years; S.D., 1.68 years), 11 strabismic amblyopes and 10 anisometropic amblyopes, were tested. Based on a display of the standard optotypes, the minimal contrast level, at which the optotypes were correctly read for all sizes of displays from a distance of 1m, was measured. The contrast ranged from 1% to 99% and the spatial frequencies ranged from 0.6 to- 30cpd using a Landolt ring composed of low (0.6- 2.9 c.p.d.), intermediate (3.0 - 12.9 c.p.d.) and high level (13.0- 30.0 c.p.d.) frequencies. As the visual acuity decreased, the mesopic contrast sensitivity function decreased along the contrast sensitivity axis. However, the peak sensitivity was noted at the same spatial frequencies. A comparison between the normal eye and the corresponding amblyopic eye showed that under mesopic conditions, the contrast sensitivity functions decreased more in the intermediate spatial frequencies than in the other spatial frequencies. The mesopic contrast sensitivity function decreased in the amblyopic eyes, which suggests the possibility of its use an adjunct to an evaluation of amblyopia.

Visual Field in Normal Korean Subjects: Traquair's "Hill of Vision"

PURPOSE: To investigate Traquair's "hill of vision" of the normal Korean subjects in the photopic and mesopic background. METHODS: Automated perimetry was performed in 152 normal subjects using Humphrey 24-2 SITA standard (photopic background, n=100) and Octopus G1 full threshold (mesopic background, n=52) program. We calculated and compared the threshold sensitivity and sensitivity deviation of the visual field by the fashion of the superior/inferior hemi-field, temporal/nasal hemi-field, quadrant, and 5 degrees ring. RESULTS: In Humphrey, average mean deviation (MD) and pattern standard deviation (PSD) were -1.22+/-0.86 and 1.43+/-0.33 dB, respectively. In Octopus, average MD and PSD were -3.39+/-1.39 and 1.67+/-0.23 dB, respectively. In both Humphrey and Octopus, the average threshold sensitivity of the inferior hemi-field was slightly higher than that of the superior hemi-field. There was no significant difference between the nasal and temporal hemi-field. The sensitivity was decreased with increasing the eccentricity. In the deviation map of the Humphrey, there were no significant differences in the comparisons of the hemifield, quadrant, and 5 degrees ring. In Octopus, there were no significant differences in the comparisons of the hemifield and quadrant. However, the sensitivity deviation was peaked at the fixation point and decreased with increasing the eccentricity. CONCLUSIONS: These results indicate that the normal Korean subjects may have lower sensitivity than the normal age-matched controls of the automated perimetry, especially in the Octopus perimetry. In addition, this study suggests that the shape of the Traquair's "hill of vision" in the normal Korean subjects might be similar to that of the normal age-matched controls in Humphrey perimetry which was performed in photopic background, but it might be flatter in Octopus perimetry which was performed in mesopic background.