Differences In Ocular Parameters Research Articles

Influence of Lifestyle Factors on Ocular Surface Parameters in Relation to Age

Purpose: To evaluate how Video Display Terminal (VDT) use, Contact Lens (CL) wear, and eyedrop use affect ocular surface parameters in participants with ocular discomfort and how these factors may vary across different age groups. Methods: The current cross-sectional study initially involved a total of 252 participants who completed a self-administered survey to collect information about ocular discomfort and lifestyle factors. This online survey was composed of an Ocular Surface Disease Index (OSDI) questionnaire and three extra questions regarding lifestyle factors (VDT use, CL wear, and eyedrop use). Only 185 symptomatic participants, those with OSDI values > 12, were scheduled to undergo a comprehensive ocular examination that included tear film osmolarity, Fluorescein Break-Up Time (FBUT), Maximum Blink Interval (MBI), and corneal staining. Results: Differences in ocular parameters and lifestyle factors across age groups (<40 years, 40–60 years, >60 years) were analyzed, along with their correlations and regression. Significant age group differences were found in OSDI, osmolarity, FBUT, and MBI (One-way ANOVA, all p ≤ 0.029). Correlations were observed between CL wear and osmolarity and MBI (Pearson’s correlation, both p ≤ 0.049). Multiple regression confirmed age associations with OSDI, osmolarity, FBUT, and MBI (Multiple linear regression, all p ≤ 0.040) and found links between VDT use and osmolarity and MBI (Multiple linear regression, both p ≤ 0.038) and between eyedrop use and OSDI (Multiple linear regression, p = 0.040). Conclusion: Aging is a primary factor affecting ocular homeostasis, with older adults showing lower FBUT and MBI values and higher osmolarity. Prolonged use of VDTs exacerbates this effect, further contributing to ocular discomfort and destabilized tear film. No associations between CL wear and any of the ocular parameters were found. Eyedrop use shows varied effects on ocular comfort across age groups, emphasizing the need for age-specific ocular care. Overall, these findings confirm that aging and extended VDT use play a significant role in ocular surface discomfort.

Short-term tolerability of commercial eyelid cleansers: A randomised crossover study

PurposeTo evaluate the short-term tolerability of five commercially available anti-demodectic eyelid cleansers; OCuSOFT Oust Demodex (OD), I-MED I-Lid’n Lash Plus (ILL+), Labtician BlephaDex (BD), Chrissanthe Eye Cleanse (EC), and Théa Blephademodex (BDdx). MethodsThirty healthy non-contact lens wearers (18 female; mean ± SD age, 33 ± 12 years) were enrolled in a prospective randomised crossover study. On separate visits, spaced at least 48 h apart, participants were randomised to receive topical application of one of five eyelid cleansers or saline. Participants rated subjective ocular discomfort during the 10-minute post-application period. Visual acuity, non-invasive tear film stability, conjunctival hyperaemia, and ocular surface staining were assessed at baseline and 10 min. ResultsNo inter-group differences in ocular parameters were noted at baseline (all p > 0.05). Ocular discomfort scores significantly exceeded baseline scores for 60 s following BD application, 120 s with OD, 135 s with BDdx, 150 s with ILL+, and 195 s with EC (all p < 0.05). Deterioration in non-invasive tear film stability, limbal conjunctival hyperaemia, as well as corneal, conjunctival, and lid margin staining was detected following EC application (all p < 0.05), and increased bulbar conjunctival hyperaemia was observed following both EC and ILL+ treatment (both p < 0.05). ConclusionsStudy outcomes highlight varying tolerability profiles with different anti-demodectic lid cleanser preparations, and the potential to induce tear film instability, conjunctival hyperaemia and ocular surface staining on application. Awareness of possible adverse effects arising from topical application of commercial anti-demodectic lid cleanser formulations may help clinicians set realistic patient expectations and encourage better compliance in their use of lid hygiene therapies.

Effect of interocular differences on binocular visual performance after inducing forward scattering

PurposeTo assess binocular visual performance by means of binocular summation on visual function after inducing monocular forward scattering, and to study the influence of interocular differences on ocular parameters.MethodsSeven young healthy subjects were recruited. Four Bangerter foils and five fog filters were used to induce monocular forward scattering. To analyse the impact of the scatter, visual acuity, contrast sensitivity, visual discrimination capacity and distance stereoacuity were measured binocularly with the filter placed over the dominant eye. Additionally, interocular differences were calculated for four ocular parameters: the Objective Scatter Index (OSI), Strehl ratio (SR), modulation transfer function cut‐off (MTF cut off) and straylight (log[s]). Binocular summation was determined for these visual functions.ResultsA statistically significant deterioration in visual acuity, contrast sensitivity and stereoacuity was seen for all of the filter conditions with respect to the natural state (baseline), with the largest change being recorded for the Bangerter foils. Similarly, the interocular difference for the three retinal image quality parameters (OSI, SR and MTF cut‐off) and log(s) increased significantly for the Bangerter foil condition, but not for the fog filters (except log(s)). Binocular summation declined gradually with the Bangerter foils, but not for the fog filters. Statistically significant correlations were found, that is, the greater the interocular differences, the lower the binocular summation of the visual functions and the greater the distance stereoacuity.ConclusionIncreased forward scattering in the dominant eye resulted in interocular differences, which reduced the overall binocular visual performance, including the binocular summation of several visual functions and distance stereoacuity. The results suggest that marked interocular differences in ocular parameters should be avoided in cases of ocular pathology, amblyopia and emmetropisation procedures (such as refractive surgery) or a monovision correction for presbyopia.

Analysis of the structural parameters and surgical effect of patients with primary angle closure glaucoma in different age groups

Objective To analyze the ocular structural parameters and the surgical effect of patients with primary angle closure glaucoma (PACG) in different age group. Methods Prospective case series study. Total 121 eyes of 62 patients with PACG were collected from Feb. 2012 to Feb. 2015 as treatment group. There were 60 eyes of 30 normal people with <40 years old as control group(group A). The anterior chamber depth (ACD), lens thickness (LD) and axial length (AL) were measured and analyzed. The treatment group underwent trabeculectomy, the surgical effects were observed. Results There were 50 eyes of 25 patients with aged <40 as group B in the treatment group. The ACD, LT and AL of group B were (1.85±0.32) mm, (4.51±0.43) mm and (21.78±1.09) mm, respectively. There were 71 eyes of 37 patients aged ≥40 as group C in the treatment group. The ACD, LT and AL were (1.79±0.23) mm, (4.56±0.68) mm and (22.29±0.83) mm, respectively. The difference of AL was statistically significant between group B and group C (P<0.01). The ACD, LT and AL of group A were (2.96±0.37) mm, (3.90±0.56) mm and (23.77±1.14) mm, respectively. The overall differences in ocular parameters were statistically significant among 3 groups (P<0.01). The difference in IOP of patients with PAEG was statistically significant between before and after surgery (P<0.01). During the follow-up period, malignant glaucoma occurred in 20% patients in group B and 1.92% patients in group C, and the difference was significant(χ2=8.371, P=0.004). Conclusion PACG patients are with shorter AL, shallow anterior chamber and thick lens.AL of PACG patients<40 years is more shorter. Trabeculectomy can effectively control the IOP, the malignant glaucoma is likely to occurr in PACG patients with<40 years old. Key words: Glaucoma, angle closure, primary; Parameters, structural; Age; Trabeculectomy

Corneal biomechanics in normal Saudi individuals

PurposeThe aim of this study was to determine and relate corneal biomechanical metrics with demographic, tomographic and refractive data in healthy Saudi people. DesignProspective, cross-sectional, observational study. ParticipantsThe study included 215 normal Saudi adult individuals. MethodsCorneal hysteresis (CH) and corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg) and corneal-compensated intraocular pressure (IOPcc) were measured by ocular response analyzer. The central keratometry (CK), central corneal thickness (CCT), and anterior chamber depth (ACD) were measured using Pentacam system. The spherical equivalent of refraction (SER) was obtained by an Auto-refractometer. ResultsThe mean CH was 11.16±2.11, CRF was 11.07±2.31 and IOP was 15.12±3.5. Mean CK, ACD, CH and CRF were distinct among gender with the significant P values of 0.05, 0.006, 0.020, and 0.047 respectively. CRF was negatively correlated with ACD (r=−0.146, P=0.032). A positive correlation was found between CRF and SER (r=0.176, P=0.010), CCT (r=0.447, p=0.000) and CH (r=0.878 and p=0.000). CH was negatively correlated with IOPcc (−0.433, p=0.000). A positive correlation was found between CH and ACD (r=−0.14, p=0.044), SER (r=0.617, p=0.014), CCT (r=0.412, p=0.000) and IOPg (r=0.183, p=0.007). ConclusionThis study demonstrated a distinct difference among gender values of corneal hysteresis and corneal resistance factor being higher in female Saudi subjects. CH and CRF values were higher in Saudi subjects than values in other populations. This may suggest the presence of ethnic differences in ocular parameters and support the importance of establishing population norms for corneal biomechanical parameters.

The Effect of Age, Accommodation, and Refractive Error on the Adult Human Eye.

To quantify changes in ocular dimensions associated with age, refractive error, and accommodative response, in vivo, in 30- to 50-year-old human subjects. The right eyes of 91 adults were examined using ultrasonography, phakometry, keratometry, pachymetry, interferometry, anterior segment optical coherence tomography, and high-resolution magnetic resonance imaging. Accommodation was measured subjectively with a push-up test and objectively using open-field autorefraction. Regression analyses were used to assess differences in ocular parameters with age, refractive error, and accommodation. With age, crystalline lens thickness increased (0.03 mm/yr), anterior lens curvature steepened (0.11 mm/yr), anterior chamber depth decreased (0.02 mm/yr), and lens equivalent refractive index decreased (0.001/yr) (all p < 0.01). With increasing myopia, there were significant increases in axial length (0.37 mm/D), vitreous chamber depth (0.34 mm/D), vitreous chamber height (0.09 mm/D), and ciliary muscle ring diameter (0.10 mm/D) (all p < 0.05). Increasing myopia was also associated with steepening of both the cornea (0.16 mm/D) and anterior lens surface (0.011 mm/D) (both p < 0.04). With accommodation, the ciliary muscle ring diameter decreased (0.08 mm/D) and the muscle thinned posteriorly (0.008 mm/D), allowing the lens to shorten equatorially (0.07 mm/D) and thicken axially (0.06 mm/D) (all p < 0.03). Refractive error is significantly correlated with not only the axial dimensions but also the anterior equatorial dimension of the adult eye. Further testing and development of accommodating intraocular lenses should account for differences in patients' preoperative refractive error.

Differences in ocular parameters between diurnal and nocturnal raptors

To establish and compare normal ocular parameters between and within diurnal and nocturnal raptor groups. Eighty-eight ophthalmically normal raptors of six nocturnal and 11 diurnal species were studied. Tear production was measured using Schirmer tear test (STT) and phenol red thread test (PRTT), and applanation tonometry was conducted. Ultrasonographic measurements of axial length (AL), mediolateral axis (ML), vitreous body (VB), and pecten length (PL) were recorded, and conjunctival cultures were obtained. A weak correlation (R=0.312, P=0.006) was found between PRTT and STT. Tear production was significantly lower in nocturnal species (P<0.001), but no difference was observed in intraocular pressure (IOP). VB and PL were significantly longer in diurnals (P<0.001 and P=0.021, respectively), and no significant difference was observed in AL and ML. When comparing results within these groups, there was a significant difference between most species for all parameters except IOP. Fifty-one percent of the examined raptors were positive for mycology or bacteriology, either on culture or PCR. The most common infectious agent isolated was Staphylococcus spp. Phenol red thread test and STT are both valid methods to measure tear production; however, a separate baseline must be determined for each species using these methods, as the results of one method cannot be extrapolated to the other. Due to significant differences observed within diurnal and nocturnal species, it appears that a more intricate division should be used when comparing these parameters for raptors, and the classification of diurnal or nocturnal holds little significance in the baseline of these data.

The biometric study in different stages of primary angle-closure glaucoma

This study compared the general and ocular biometric characteristics of normal, primary angle closure (PAC), and primary angle-closure glaucoma (PACG) patients to better understand the possible relationship between differences in ocular parameters that might predict risk for PACG in PAC patients. One hundred normal, 90 PAC, and 90 PACG eyes were retrospectively reviewed. General characteristics such as age, gender, body height, body weight, blood pressure, pulse, systemic diseases, and education level were recorded. Ocular findings included visual acuity, intraocular pressure, refraction, cup to disc ratio, and ocular biometry. Ocular biometry was obtained by A-scan ultrasonography (Digital A/B scan 5500; Sonomed Inc., Lake Success, NY, USA). The parameters recorded were anterior chamber depth (ACD), lens thickness (LT), axial length (AXL), lens/axial length factor (LAF), and relative lens position (RLP). Although the controls, PAC group, and PACG group were found to be significantly different in age (62.7±9.8; 65.3±7.5; and 66.0±7.4, respectively), there were no gender differences. With regard to ocular parameters, the ACD tended to decrease and the LT and LAF tended to increase from normal to PAC to PACG. The eyes of the PACG group had significantly shallower ACD (P<0.001) and thicker lens (P<0.001) than those of the PAC group. While PAC had similar lens position to the control group, PACG had more anteriorly positioned lens than the PAC group (P<0.001). Logistic regression analysis found a significant association between a decrease in ACD and increased risk of PACG (odds ratio (OR)=3.59 for 0.2 mm decrease in ACD) as well as a significant association between an increase in LT and increased risk of PACG (OR=1.30). In addition to LT, a shallower ACD owing to a change in RLP may have a role in the progression from PAC to PACG. Owing to the differences of certain biometric characteristics between PAC and PACG, A-scan ultrasonography might potentially be used for the early detection of PACG in PAC eyes.

Ocular Pulse Amplitude in Patients with Thyroid-associated Ophthalmopathy

To determine ocular pulse volume values in patients with thyroid-associated ophthalmopathy with normal intraocular pressure, and to test the hypothesis that changes in orbital tissue that accompany thyroid-associated ophthalmopathy can in turn give changes in choroidal perfusion. In a prospective study, we evaluated 30 eyes of 30 consecutive patients with TAO, and 30 eyes of 30 healthy subjects. Complete ophthalmologic examination including dynamic contour tonometry was done. Possible differences in ocular parameters between the tested groups were assessed. . No significant difference was found in ocular pulse volume values between the tested subjects (paired test p=0.23). . The orbit tissue changes that are involved in thyroid-associated ophthalmopathy do not have much implication on choroidal perfusion, at least when intraocular pressure values remain within the normal range.

A comparison of refractive development between two subspecies of infant rhesus monkeys ( Macaca mulatta)

Purpose Different subspecies of rhesus monkeys ( Macaca mulatta) that are derived from different geographical locations, primarily Indian and China, are commonly employed in vision research. Substantial morphological and behavioral differences have been reported between Chinese- and Indian-derived subspecies. The purpose of this study was to compare refractive development in Chinese- and Indian-derived rhesus monkeys. Methods The subjects were 216 Indian-derived and 78 Chinese-derived normal infant rhesus monkeys. Cross-sectional data were obtained at 3 weeks of age for all subjects. In addition, longitudinal data were obtained from 10 Indian-derived (male = 5, female = 5) and 5 Chinese-derived monkeys (male = 3, female = 2) that were reared with unrestricted vision. Ocular and refractive development was assessed by retinoscopy, keratometry, video-based ophthalmophakometry, and A-scan ultrasonography. Results Although the course of emmetropization was very similar in these two groups of rhesus monkeys, there were consistent and significant inter-group differences in ocular dimensions and refractive error. Throughout the observation period, the Chinese-derived monkeys were on average about 0.4 D less hyperopic than the Indian-derived monkeys and the Chinese-derived monkeys had longer overall axial lengths, deeper anterior and vitreous chamber depths, thicker crystalline lenses, flatter corneas and lower powered crystalline lenses. Conclusions The ocular differences observed in this study presumably reflect genetic differences between subspecies but could reflect the differences in the genetic pool between isolated colonies rather than true subspecies differences. Nonetheless, the substantial ocular differences that we observed emphasize that caution must be exercised when comparing and/or pooling data from rhesus monkeys obtained from different colonies. These inter-subspecies differences might be analogous to the ethnic differences in ocular parameters that have been observed in humans.

Clinical performance and factors affecting the physical fit of a soft toric frequent replacement contact lens

Background: Differences in ocular parameters between Chinese and Caucasian eyes, may lead to differences in the success rate of soft contact lens fittings. As most disposable or frequent replacement lenses are manufactured based on data of Caucasian eyes, the aim of this study was to investigate the clinical performance and factors affecting die preliminary fitting of a ‘one‐fit’ bi‐weekly replacement soft toric lens on Hong Kong (HK)‐Chinese.Method: Forty‐one HK‐Chinese were fitted with Acuvue soft toric lenses (on one eye only). The success rate, die comfort, vision and die effects of central corneal curvature, horizontal visible iris diameter (HVID) and palpebral aperture size (PAS) on the physical fit of die toric lenses were determined.Results: Twenty‐four of 41 eyes (58.6 per cent) attained acceptable fit and satisfactory vision with these lenses. The main reason for unsuccessful lens fit was loose fitting. Only central corneal curvatures were significandy correlated (statistically) to the looseness of the lens.Discussion: The results showed diat about 40 per cent of our subjects were unable to obtain acceptable fit with this one‐fit frequent replacement lens, the main reason for which was loose fit. This was expected due to the steeper corneas of the Chinese eyes and we would expect similar results widi odier one‐fit soft lenses. Only die central corneal radii were significandy correlated widi die looseness of the lens fit. However, this factor was not die main factor affecting die contact lens fitting. HVID and PAS did not appear to play any significant role in die physical fit of diis lens. As tiiere are individual variations of lens fitting behaviour, trial lens fitting assessment is die most suitable way to select the appropriate lens.