Assessment of lipid layer patterns in domestic dogs and rabbits: an observational study

Background

Maintaining a stable tear film is crucial for having healthy human and animal vision. Animals are expected to have thicker lipid layers than humans due to living in high-temperature and humid environments.

Aim

The study aimed to evaluate the lipid layer patterns (LLPs) in Arabian dogs and rabbits using a non-invasive, practical, and easy-to-use device and compare them to humans with healthy eyes.

Methods

The study included 75 domestic Arabian dogs (42 males and 33 females; mean ± SD = 6.1 ± 12.7 months) and 75 rabbits (37 males and 38 females; mean ± SD = 3.1 ± 3.4 months). In addition, 75 individuals with healthy eyes (39 males and 36 females; mean ± SD = 25.7 ± 5.0 years) were included for comparison. EASYTEAR View+ assessed the LLP in each animal's and individual's right eye.

Results

The median LLP grades significantly differed between dogs and humans (Mann-Whitney U test, p < 0.001). Similarly, the LLP grades differed significantly between rabbits and humans (Mann-Whitney U test, p < 0.001). No significant difference (Mann-Whitney U test) in the LLP grades between dogs and rabbits was found. The analysis indicated that most dogs had either an A (34.7%) or a B grade (37.3%). Similarly, rabbits had predominantly A or 1 (46.7%) and B (30.7%) grades. On the other hand, humans had predominantly D (53.3%) and E (30.7%) grades.

Conclusion

The EASYTEAR View+ has been employed to assess LLP in dogs and rabbits, and the measurements were compared to those of humans with normal ocular health. Dogs and rabbits have thinner lipid layers than healthy humans.

Evaluation of tear meniscus height and lipid layer patterns in the tear film in domestic cats: An observational study

Background

Healthy vision in humans and animals requires a stable tear film. The environmental factor could affect the status of the tear film. Therefore, assessing the tear film in animals is essential to avoid visual system disturbance.

Aim

The current research used a noninvasive device to evaluate the tear meniscus height (TMH) and lipid layer pattern (LLP) in domestic cats. In addition, the scores were compared with those of humans with healthy eyes.

Methods

Fifty-four domestic cats (28 males and 26 females; mean ± SD = 13.9 ± 18.2 months) were randomly selected and included in the study. The cats were healthy, without any ocular disorders or diseases. Fifty-four healthy eye subjects (27 males and 27 females; mean ± SD = 25.6 ± 5.1 years) were randomly recruited and took part in the study for comparison. EASYTEAR View+ was used, for the first time, to assess the tear film parameters on the right eye of each subject. The examiner allowed a 5-minute gap between the tests. Each test was performed by the same examiner three times, followed by calculating the mean scores.

Results

Significant differences (Mann-Whitney U test) were found in the median scores of LLP (p = 0.009) between cats and subjects with healthy eyes. The median TMH score was higher in cats (0.18 mm) than in humans (0.14). However, no significant difference (Mann-Whitney U Test, p = 0.210) exists in the TMH scores between cats and humans. The LLP analysis indicated that a dense white-blue lipid layer (grade 4 or D; lipid layer thickness, LLT, = approximately 80 nm) was predominant in both cats (N = 24, 44.4%) and humans (N = 29, 53.7%). In comparison, variable colors lipid layer (grade 5 or E; LLT = 90-140 nm) was a minority in cats (N = 5, 9.3%) and common in humans (N = 16, 29.6%). The statistical analysis indicated medium correlations between cats' TMH and LLP scores (r = 0.431, p < 0.01) and between age and TMH scores in humans (r = 0.440, p < 0.01). In addition, it indicated a weak correlation (r = 0.291, p < 0.05) between the LLP scores in cats and humans.

Conclusion

Assessing animals' tear film is essential to avoid any ocular disorders. EASYTEAR View+ is efficiently used to evaluate domestic cats' TMH and LLP. Cats have thicker lipid layers and longer TMH comparable to those reported for humans with healthy eyes.

Synergistic Effect of Nilavembu Choornam-Gold Nanoparticles on Antibiotic-Resistant Bacterial Susceptibility and Contact Lens Contamination-Associated Infectious Pathogenicity

Antibiotic-resistant bacterial colonies mitigate rapid biofilm formation and have complex cell wall fabrications, making it challenging to penetrate drugs across their biofilm barriers. The objective of this study was to investigate the antibacterial susceptibility of antibiotic-resistant bacteria and contact lens barrenness. Nilavembu Choornam-Gold Nanoparticles (NC-GNPs) were synthesized using NC polyherbal extract and characterized by UV-visible spectrophotometer, SEM-EDX, XRD, Zeta sizer, FTIR, and TEM analysis. Contact lenses with overnight cultures of antibiotic-resistant bacteria K. pneumoniae and S. aureus showed significant differences in growth, biofilm formation, and infection pathogenicity. The NC-GNPs were observed in terms of size (average size is 57.6 nm) and surface chemistry. A zone of inhibition was calculated for K. pneumoniae 18.8 ± 1.06, S. aureus 23.6 ± 1.15, P. aeruginosa 24.16 ± 0.87, and E. faecalis 24.5 ± 1.54 mm at 24 h of NC-GNPs alone treatment. In electron microscopy studies, NC-GNP-treated groups showed nuclear shrinkage, nuclear disintegration, degeneration of cell walls, and inhibited chromosomal division. In contrast, normal bacterial colonies had a higher number of cell divisions and routinely migrated toward cell multiplications. NC-GNPs exhibited antibacterial efficacy against antibiotic-resistant bacteria when compared to NC extract alone. We suggest that NC-GNPs are highly valuable to the population of hospitalized patients and other people to reduce the primary complications of contact lens contamination-oriented microbial infection and the therapeutic efficiency of antibiotic-resistant bacterial pathogenicity.

Effect of monovalent electrolyte solutions on the human tear ferning pattern

PURPOSE

To investigate the effect of the addition of a low concentration of sodium chloride (NaCl) and potassium chloride (KCl) solutions on the tear ferning (TF) patterns of tears collected from humans.

METHODS

A tear sample (20 μL) was collected from the right eye of 23 males and 7 females (25.4 ± 6.6 years). The tears were collected in one sitting for healthy subjects (N = 13). For dry eye participants (N = 17), the tear samples were collected in two separate settings with five minutes gap in between. A sample (1 μL) from each tear was dried on a glass slide, and the obtained ferns were observed using a microscope and graded using the five-point TF grading scale. Mixtures of tear samples (0.5 μL) and different volumes (0.5-2.5 μL) of each electrolyte (10-30 mg in 100 mL of water) solution were prepared, and their TF patterns were recorded and compared with those of the corresponding pure tears.

RESULTS

Significant improvements (Wilcoxon test, P < 0.001) have been seen in the TF grades of the tear samples after the addition of NaCl and KCl solutions. A significant difference (Wilcoxon test, P = 0.016) was found between the TF grades when NaCl and KCl solutions were added to the tear samples. The TF grades of pure tears collected from dry-eye subjects ranged from 2.1 to 3.5, based on the five points grading scale, and decreased to be in the range of 0.4 to 1.6 after the addition of electrolyte solutions. While the TF grades of pure tears collected from normal-eye ranged from 1.2 to 1.9 and improved after the addition of electrolyte solution to be in the range of 0.4 to 1.5.

CONCLUSIONS

The TF test was used in vitro to assess the impact of the addition of a low concentration of sodium and potassium chloride solutions on tears collected from humans. The TF grades of human tears significantly improved after the addition of either sodium or potassium chloride solution. The mechanism for the improvement in TF grades due to the addition of electrolyte solutions must be investigated.

Modifications of Polymers through the Addition of Ultraviolet Absorbers to Reduce the Aging Effect of Accelerated and Natural Irradiation

The photooxidative degradation process of plastics caused by ultraviolet irradiation leads to bond breaking, crosslinking, the elimination of volatiles, formation of free radicals, and decreases in weight and molecular weight. Photodegradation deteriorates both the mechanical and physical properties of plastics and affects their predicted life use, in particular for applications in harsh environments. Plastics have many benefits, while on the other hand, they have numerous disadvantages, such as photodegradation and photooxidation in harsh environments and the release of toxic substances due to the leaching of some components, which have a negative effect on living organisms. Therefore, attention is paid to the design and use of safe, plastic, ultraviolet stabilizers that do not pose a danger to the environment if released. Plastic ultraviolet photostabilizers act as efficient light screeners (absorbers or pigments), excited-state deactivators (quenchers), hydroperoxide decomposers, and radical scavengers. Ultraviolet absorbers are cheap to produce, can be used in low concentrations, mix well with polymers to produce a homogenous matrix, and do not alter the color of polymers. Recently, polyphosphates, Schiff bases, and organometallic complexes were synthesized and used as potential ultraviolet absorbers for polymeric materials. They reduced the damage caused by accelerated and natural ultraviolet aging, which was confirmed by inspecting the surface morphology of irradiated polymeric films. For example, atomic force microscopy revealed that the roughness factor of polymers' irradiated surfaces was improved significantly in the presence of ultraviolet absorbers. In addition, the investigation of the surface of irradiated polymers using scanning electron microscopy showed a high degree of homogeneity and the appearance of pores that were different in size and shape. The current work surveys for the first time the use of newly synthesized, ultraviolet absorbers as additives to enhance the photostability of polymeric materials and, in particular, polyvinyl chloride and polystyrene, based mainly on our own recent work in the field.

Kawasaki disease in an infant after administration of hexavalent vaccine

Kawasaki disease is a vascular disorder of unknown etiology that affects children. Kawasaki disease mainly involves medium-sized blood vessels and may cause cardiovascular complications, particularly coronary artery aneurysms. Concern has been raised against various types of vaccines becoming potential risk factors for Kawasaki disease. Here, we describe a case of a 4-month-old Saudi infant who presented with incomplete Kawasaki disease a few hours after receiving his hexavalent vaccine and there was a significant dilatation of all coronary arteries. Although a relationship between vaccinations and Kawasaki disease has been suggested, there is no strong evidence of an increased risk or causal association. This possibility of adverse effects is rare but should be observed and further investigated.

Radiographic evaluation of bone density in dentulous and edentulous patients in Riyadh, KSA

Background

The Cone Beam Computed Tomography (CBCT) is currently being used as the most common diagnostic method to evaluate the bone density of the maxilla and the mandible for planning dental implant. Aim: The aim of the study is to check the quantitative alveolar bone density in complete or partial edentulous and dentulous male and female patients among Riyadh sample population in Saudi Arabia.

Materials and Methods

The study involved a cross-sectional analysis of 231 consecutive CBCT images of 231 different patients (115 males and 116 females). The scans were of Saudi National patients who were partially or completely edentulous without any bone infections in the maxilla and the mandible. The findings are presented as descriptive statistics and inferential statistics: student -t-test for two group means, ANOVA for three groups, Post-hoc LSD test for multiple comparisons, Levene statistics for testing the homogeneity of variances and a statistical significance at 5% level.

Results

Comparison of mean alveolar bone density in maxillae of dentulous male smokers showed a statistically significant difference for bucco-cortical plate and cancellous bone among different regions. In dentulous male nonsmokers, no significant difference was observed for maxillary regions, while in mandibular areas, a statistically significant difference was seen for buccal cortex, palatal cortex, and cancellous bone among different regions. While studying the scans of female dentulous patients, a statistically significant difference was observed in alveolar bone density for all the areas.

Conclusion

Evaluation of bone density is an important step in treatment planning and this study was aimed to provide insight into bone density patterns of population in Riyadh, Saudi Arabia. Further similar studies in different populations can help in planning for more efficient treatment outcomes.

2-[3-(4-Chlorophenyl)-5-(4-fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl]-5-[(4-fluorophenyl)diazenyl]-4-methylthiazole

The molecule of the title compound, C25H18ClF2N5S, comprises almost co-planar fluorophenyl, methylthiazolyl, pyrazolyl and chlorophenyl rings with the second fluorophenyl ring almost perpendicular to this plane. One fluorophenyl group is disordered over two components of occupancy ratio 0.767 (10):0.233 (10) related by a 24.2 (8)° twist. In the crystal, two molecules related by inversion symmetry are linked by a pair of C—H...F contacts in an R(8)2 2 geometry.

Assessment of tear film in subjects with a high body mass index

PURPOSE

The aim of the study was to assess the tear film in subjects with a high body mass index (BMI).

METHODS

Twenty male subjects aged 23-42 years (mean ± standard deviation =31.3±5.7 years) with a high BMI [median (interquartile range) =31.8 (5.2) kg/m2] were recruited. An age-matched control group of twenty male subjects aged 22-38 years with a normal BMI [20.5 (2.8) kg/m2] also participated in the study.

RESULTS

There were significant (Kolmogorov-Smirnov test; P<0.05) differences in the BMI, non-invasive tear break-up time (NITBUT), and tear ferning (TF) scores between the study and control groups. There were some differences in the ocular surface disease index (OSDI), tear meniscus height (TMH), and phenol red thread (PRT) scores between the study and control groups, but these differences were not significant (Kolmogorov-Smirnov test; P>0.05). For the study group, the NITBUT and TF tests mean scores showed a dry eye condition (8.5±2.8 s and 2.0±1.1, respectively). However, these two tests showed a normal eye condition within the control group (14.7±2.8 s and 0.7±0.6, respectively). The TMH score had strong correlations with the NITBUT (r=0.711; P=0.001) and PRT scores (r=0.566; P=0.009) and strong negative correlations with age (r=-0.503; P=0.024) and the OSDI scores (r=-0.520; P=0.018). The TF score had a strong correlation with age (r=0.579; P=0.007) and strong negtive correlations with the scores from the NITBUT (r=-0.525; P=0.018), TMH (r=-0.575; P=0.008), and PRT (r=-0.773; P=0.001) tests.

CONCLUSION

The acquired data suggest a high BMI has an effect on the quality of tears. The quality of tears seems to be lower in subjects with a high BMI compared with normal subjects. On the other hand, the tear volume in subjects with a high BMI was just as high and adequate as for normal eye subjects.

A comparative study of the quality of non-stimulated and stimulated tears in normal eye male subjects using the tear ferning test

PURPOSE

To evaluate and compare the tear ferning patterns of non-stimulated and stimulated tears in normal eye male subjects using the tear ferning test.

METHODS

Thirty-five male subjects aged 20-38 years with normal eyes were enrolled in the study. Subjects with dry eye or with a risk factor for eye dryness (eg, recent ocular surgery, contact-lens wearers, smokers, anemic, diabetes, and thyroid gland problems) were excluded from the study. Dry eye subjects were excluded based on the ocular surface diseases index scores, non-invasive tear break-up time, and tear meniscus height measurements from the right and left eyes. A tear sample was collected from both eyes in each subject to perform the tear ferning test for non-stimulated tears. After 10 mins, the tears were stimulated using a Schirmer strip, a tear sample was collected from both eyes in each participant, the tear ferning test was performed, and the ferns were graded based on the five-point tear ferning grading scale.

RESULTS

The average tear ferning grade [median (interquartile range)] for non-stimulated tears from the right and left eyes was 0.60 (1.25) and 0.50 (1.31), respectively. For stimulated tears, the average tear ferning grade from the right and left eyes was 0.50 (1.05) and 0.75 (1.25), respectively. There was no significant difference in the tear ferning grades obtained from non-stimulated and stimulated tears (Wilcoxon test, P>0.05).

CONCLUSION

This study found no significant difference in the tear ferning patterns obtained from non-stimulated and stimulated tears, or between the tear ferning patterns in the tears collected from the right and left eyes before and after stimulating tears. It seems that there were no changes in the chemical composition of tears before and after stimulation, possibly due to the steady concentration of electrolytes and lipids within the tear film for both non-stimulated and stimulated tears.

An assessment of the ocular tear film in patients with thyroid disorders

Objective: To investigate the ocular tear film in patients with thyroid disorders using various tests. Methods: The study involved the assessment of the ocular tear film in 20 patients with thyroid disorders (6 men and 14 women) aged 18-43 years (mean±standard deviation=34.3±3.2 years). An age-matched control group consisting of 20 subjects (8 males and 12 females) ranging in age from 18 to 43 years (31.3±2.9 years) was also examined under similar conditions. All patients completed the Ocular Surface Disease Index questionnaire, followed by the tear ferning test within the right eye. A phenol red thread test was carried out 10 mins later followed by the fluorescein tear break-up test with a 10-min gap between the tests being implemented. Results: The median score for the Ocular Surface Disease Index (P<0.05) showed the condition of mild dry eyes [median (IQR)=15.5 (21.9)] in patients with thyroid disorders compared to the control group [5.6 (3.6)]. The mean score for the phenol red thread test within both the right and left eyes showed acceptable tear volumes of 11.7±8.1 and 10.5±7.4 mm, respectively, but this was much lower (P<0.05) compared to those recorded within the control group (22.2±6.5 and 20.7±5.2 mm, respectively). In addition, the mean for the tear break-up time (P<0.05) scores in both eyes within the patients with thyroid disorders revealed a certain degree of eye dryness (4.9±1.6 and 4.2±1.9 s), while the control group showed normal eye scores (13.2±2.6 and 12.3±2.2 s). The median score for tear ferning grades showed eye dryness [2.0 (2.2)] within the study group and normal eyes [1.2 (0.9)] within the control group. Conclusions: Patients with thyroid disorders have a significant level of eye dryness compared to normal eye subjects.

Effect of Refresh Plus® preservative-free lubricant eyedrops on tear ferning patterns in dry eye and normal eye subjects

Purpose

To evaluate the tear ferning patterns in dry eye and normal eye subjects in the 3 hours following application of Refresh Plus^® preservative-free lubricant eyedrops.

Methods

Thirty men with dry eye (mean age 22.14±2.34 years) and 30 age-matched men with normal eyes (mean age 23.91±3.24 years) were enrolled. Eyes were classified as normal or dry based on their Ocular Surface Disease Index score, tear meniscus height, and noninvasive tear breakup time. The tear ferning test was performed before and 30, 60, 120, and 180 minutes after application of a Refresh Plus eyedrop into the right eye in each subject.

Results

There was a significant change in tear ferning grade after application of Refresh Plus eyedrops (P=0.02, Wilcoxon test) in the group with dry eye, but not in the normal eye group (P=0.19, Wilcoxon test). The correlation of tear ferning grade was moderate (r=0.484, P=0.049) at 60 minutes after application of the eyedrops and strong at 120 minutes (r=0.560, P=0.019) and 180 minutes (r=0.726, P=0.001). There was also a strong correlation (r=0.865, P=0.001) between tear ferning grades obtained 120 and 180 minutes after application. In the normal eye group, there was a moderate (r=0.407, P=0.029) correlation between tear ferning grades obtained before and 60 minutes after application of the eyedrops. There was also a strong correlation (r=0.532, P=0.003) between tear ferning grades obtained 120 and 180 minutes after application.

Conclusion

Tear ferning patterns improved significantly after application of Refresh Plus preservative-free lubricant eyedrops in subjects with dry eye. Artificial tears containing sodium carboxymethylcellulose, such as Refresh Plus, can be used to improve tear ferning patterns in dry eye for at least 3 hours.

Effects of short-term oral vitamin A supplementation on the ocular tear film in patients with dry eye

Objective

To investigate the effects of short-term oral vitamin A supplementation on the ocular tear film in patients with dry eye.

Methods

In total, 30 male patients with dry eye (age range, 18–38 years; mean age, 25.2±2.8 years) who did not wear contact lenses or exhibit any ocular (other than dry eye) or systemic diseases were included, along with 30 age-matched men (control group; mean age, 24.5±2.3 years) with healthy eyes. Subject exclusion was based on the findings of the McMonnies questionnaire (cutoff score for dry eye: 14.5) and slit-lamp biomicroscopy. All subjects received an oral vitamin A supplement at a daily dose of 1,500 mg for 3 consecutive days. The phenol red thread (PRT) test was performed along with assessments of tear ferning (TF), tear osmolarity, and the tear break-up time (TBUT) before and 24 hours after the third dose of the vitamin A supplement. A 10-minute interval was observed between different tests.

Results

In the dry eye group, the TF grade (Wilcoxon test, P=0.01) exhibited a significant decrease, while the tear osmolarity value (t-test, P=0.01) exhibited a significant increase after vitamin A supplementation. The PRT test findings (P=0.17) and TBUT (P=0.49) showed no significant differences before and after vitamin A supplementation. In the control group, vitamin A supplementation showed no significant effects on TF (P=0.74), tear osmolarity (P=0.55), the TBUT (P=0.19), and the PRT test scores (P=0.48).

Conclusion

Our findings suggest that short-term oral vitamin A supplementation improves the quality, but not quantity, of tears in patients with dry eye. Future studies should involve larger patient samples and longer periods of vitamin A supplementation.

The acute effect of a single dose of green tea on the quality and quantity of tears in normal eye subjects

Objective

The study aimed to investigate the acute effect of a single dose of green tea on the quality and quantity of tears in normal eye subjects.

Methods

Forty normal eye subjects (22 men and 18 women) aged 19–39 years were enrolled in the study. Also, an age matching control group (20 males and 20 females) was enrolled for comparison. McMonnies dry eye symptoms questionnaire and slit lamp were used for the exclusion criteria determination. Phenol red thread (PRT) test was performed on both eyes of each subject. A tear sample was collected from the lower tear meniscus of the right eye of each subject for the tear ferning (TF) test, which was performed before (30 minutes) and after (60 minutes) drinking green tea.

Results

The median PRT measurement after green tea consumption was lower (median [IQR]=23.50 [8.00] mm) compared to that before consumption (median [IQR]=27.00 [8.75] mm). In contrast, the median TF grade was significantly higher following green tea consumption than that before consumption (median [IQR]=2.65 [1.23] vs 1.50 [0.88] mm, respectively). The results show that TF grades increased in 97.5%, and the red phenol thread scores decreased in 80% of the subjects after green tea consumption compared to those before consumption. The PRT readings and TF grades were significantly different (P<0.05) before and after green tea consumption.

Conclusion

Drinking green tea could have a significant effect on the eye tear film quality. Tear quality appeared to decrease after green tea consumption.

Assessment of tear-evaporation rate in thyroid-gland patients

Objective

To assess the tear-evaporation rate in thyroid-gland patients using a VapoMeter.

Methods

Twenty thyroid gland patients aged 18-43 years (mean 34.3±6.3 years) completed the study. Additionally, an age-matched control group of 20 patients aged 18-43 years (32.2±5.1 years) was enrolled in the study for comparison purposes. An Ocular Surface Disease Index dry-eye questionnaire was completed, followed by a test to determine the tear-evaporation rate using the VapoMeter. The test was performed three times per subject by the same examiner. Two readings were obtained each time.

Results

Significant differences (P<0.05) were found between mean Ocular Surface Disease Index and tear-evaporation-rate scores within the study and control groups. The average tear-evaporation rate was much higher in the study group (median 41.2 [IQR 41.4] g/m²⋅h) than the control group (15.7 [13.7] g/m²⋅h). Moreover, the average Ocular Surface Disease Index score for thyroid-gland patients was much higher (15.6 [23.4]) compared to the control group (5.5 [7.50]).

Conclusion

The tear-evaporation rate in thyroid-gland patients was found to be much higher than normal-eye subjects.

Assessment of the tear film in normal eye subjects after consumption of a single dose of hot peppermint drink

Objective: To test the effect of a single dose of hot peppermint consumption on the tear film in normal eye subjects. Methods: Thirty healthy male subjects aged 18-39 years (23.20±2.17 years) were enrolled. Also, an age-matched control group of 30 male subjects (19-39 years, 23.50±0.70 years) was enrolled to test the effect of the hot water. Tear meniscus height (TMH), noninvasive tear breakup time (NITBUT), and tear ferning (TF) tests were performed for each patient 30 mins before and 60 mins after they drank hot peppermint. Results: Mean TMH measurements were higher postintervention (0.32±0.07) than preintervention (0.27±0.04 mm). Similarly, mean TF grades were significantly higher (2.07±1.20) postintervention than preintervention (0.84±0.71). By contrast, mean NITBUT was lower postintervention than preintervention (11.57±3.17 and 15.84±3.36, respectively). TMH measurements increased in 90% of the subjects. Conversely, NITBUT decreased in 96.7% of the subjects. For the control group that tests the effect of drinking hot water, the scores did not differ significantly in the three tests pre- and postintervention (P˂0.05). TF grades increased in 93.3% of the subjects, postintervention. Conclusion: Tear film quality decreases significantly after peppermint beverage consumption. A similar observation has been made on the consumption of hot green tea drink.

Analysis of basal and reflex human tear osmolarity in normal subjects: assessment of tear osmolarity

PURPOSE

The aim of this study is to evaluate the difference between reflex and basal tear osmolarity among healthy normal subjects.

METHOD

The right eyes of 20 healthy normal male subjects aged 20 to 40 years were recruited for this study. The inclusion criteria for the subjects were the Ocular Surface Disease Index questionnaire score of less than 12 and wetting length of the phenol red thread of more than 10 mm. Tear film osmolarity was assessed using TearLab osmometer. Basic tear osmolarity was measured normally without inducing any irritation to the eye. In order to stimulate reflex tear, subjects were asked to open their eye as long as they can till they feel ocular surface irritation (minimum 20 s).

RESULTS

The mean score on the Ocular Surface Disease Index questionnaire was 5.5 ± 3. The mean value obtained from the phenol red thread was 21 ± 4.5 mm. There were no statistically significant differences between the osmolarity readings of basal and reflex tear osmolarity (p > 0.05). The mean value was 308 ± 12 and 306 ± 9 mOsm/l for basic and reflex tear osmolarity, respectively.

CONCLUSION

This study found that the osmolarity of the basal and reflex tears fell within the same range. The values found in this study are in agreement with published results for normal subjects.

Crystal structure of 3-tert-butyl-3-hydroxy-1,3-dihydro-2H-pyrrolo[3,2-c]pyridin-2-one, C11H14N2O2

C11H14N2O2, orthorhombic, P212121 (no. 19), a = 7.5411(2) Å, b = 11.5148(2) Å, c = 12.5370(2) Å, V = 1088.64(4) Å3, Z = 4, R gt (F) = 0.0301, wR ref (F 2 ) = 0.0826, T = 296 K.

Evaluation of visual stress symptoms in age-matched dyslexic, Meares-Irlen syndrome and normal adults

AIM

To examine the prevalence of dyslexia and Meares-Irlen syndrome (MIS) among female students and determine their level of visual stress in comparison with normal subjects.

METHODS

A random sample of 450 female medical students of King Saud University Riyadh (age range, 18-30y) responded to a wide range of questions designed to accomplish the aims of this study. The detailed questionnaire consisted of 54 questions with 12 questions enquiring on ocular history and demography of participants while 42 questions were on visual symptoms. Items were categorized into critical and non-critical questions (CQ and NCQ) and were rated on four point Likert scale. Based on the responses obtained, the subjects were grouped into normal (control), dyslexic with or without MIS (Group 1) and subjects with MIS only (Group 2). Responses were analysed as averages and mean scores were calculated and compared between groups using one way analysis of variance to evaluate total visual stress score (TVSS=NCQ+CQ), critical and non-critical visual stress scores. The relationship between categorical variables such as age, handedness and condition were assessed with Chi-square test.

RESULTS

The completion rate was 97.6% and majority of the respondents (92%) were normal readers, 2% dyslexic and 6% had MIS. They were age-matched. More than half of the participants had visited an eye care practitioner in the last 2y. About 13% were recommended eye exercises and one participant experienced pattern glare. Hand preference was not associated with any condition but Group 1 subjects (3/9, 33%) were significantly more likely to be diagnosed of lazy eye than Group 2 (2/27, 7%) and control (27/414, 7%) subjects. The mean±SD of TVSS responses were 63±14 and it was 44±9 for CQ and 19±5 for NCQ. Responses from all three variables were normally distributed but the CQ responses were on the average more positive (82%) in Group 2 and less positive (46%) in Group 1 than control. With NCQ, the responses were equally less positive in Group 1 and 2 than control. Group 2 subjects showed significantly higher TVSS (P=0.002), NCQ (P=0.006) and CQ (P=0.008) visual stress scores than control but no difference between Group 1 and control subjects, was observed for all scores (P>0.05, for all comparisons).

CONCLUSION

The prevalence of dyslexia and MIS among Saudi female students was 2% and 6%, respectively. Critical questions performed best for assessing visual stress symptoms in dyslexic and MIS subjects. Generally, students with MIS were more sensitive to visual stress than normal students but dyslexics were more likely to present with a lazy eye than MIS and normal readers.

Crystal structure of 2-(2-methyl-phen-yl)-1,3-thia-zolo[4,5-b]pyridine

In the title mol-ecule, C13H10N2S, the dihedral angle between the planes through the non-H atoms of the methylbenzene and thi-azo-lopyridine groups is 36.61 (5)°. In the crystal, the thi-azo-lopyridine groups of inversion-related mol-ecules overlap, with a minimum ring-centroid separation of 3.6721 (9) Å. Furthermore, the methylbenzene groups from neighbouring mol-ecules inter-act edge-to-face at an angle of 71.66 (5)°. In addition, weak C-H⋯ N hydrogen bonds form chains exending along [100].

Crystal structure of 3-amino-2-propyl-quinazolin-4(3H)-one

In the title mol-ecule, C11H13N3O, the propyl group is almost perpendicular to the quinazolin-4(3H)-one mean plane, making a dihedral angle of 88.98 (9)°. In the crystal, mol-ecules related by an inversion centre are paired via π-π overlap, indicated by the short distances of 3.616 (5) and 3.619 (5) Å between the centroids of the aromatic rings of neighbouring mol-ecules. Inter-molecular N-H⋯N and N-H⋯O hydrogen bonds form R 6 (6)(30) rings and C(5) chains, respectively, generating a three-dimensional network. Weak C-H⋯O inter-actions are also observed.

Crystal structure of 2,2-dimethyl-N-(5-methyl-pyridin-2-yl)propanamide

There are two mol-ecules in the asymmetric unit of the title compound, C11H16N2O. The pyridine rings and amide groups overlap almost perfectly (r.m.s. overlay fit = 0.053 Å), but the tertiary butyl groups have different orientations: in one mol-ecule, one of the methyl C atoms is syn to the amide O atom [O-C-C-C = -0.8 (3)°] and in the other the equivalent torsion angle is 31.0 (2)°. In the crystal, the two independent mol-ecules are linked by a pair of N-H⋯N hydrogen bonds in the form of an R 2 (2)(8) loop to form a dimer. A C-H⋯O inter-action connects the dimers into [100] chains.

Crystal structure of 2-(1-methyl-eth-yl)-1,3-thia-zolo[4,5-b]pyridine

In the title mol-ecule, C9H10N2S, one of the methyl groups is almost co-planar with the thia-zolo-pyridine rings with a deviation of 0.311 (3) Å from the least-squares plane of the thia-zolo-pyridine group. In the crystal, weak C-H⋯N hydrogen-bonding inter-actions lead to the formation of chains along [011].

Crystal structure of 2,2-dimethyl-N-(pyridin-3-yl)propanamide

In the title compound, C10H14N2O, the pyridine ring is inclined to the mean plane of the amide moiety [N-C(=O)C] by 17.60 (8)°. There is an intra-molecular C-H⋯O hydrogen bond present involving the carbonyl O atom. In the crystal, mol-ecules are linked via N-H⋯N hydrogen bonds, forming chains propagating along [100]. The tert-butyl group is disordered over two sets of sites with a refined occupancy ratio of 0.758 (12):0.242 (12).

Eye rubbing-induced changes in intraocular pressure and corneal thickness measured at five locations, in subjects with ocular allergy

AIM

To assess the effects of eye rubbing on corneal thickness (CT) and intraocular pressure (IOP) measurements obtained 0-30min after habitual eye rubbing in symptomatic patients.

METHODS

Measurements of IOP and CT were obtained at five locations (central, temporal, superior, nasal and inferior) before, and every 5min for 30min interval after 30s of eye rubbing, for 25 randomly selected eyes of 14 subjects with ocular allergy and 11 age-matched normals. Differences in measurements were calculated in each group [Baseline measurements minus measurements recorded at each time interval after eye rubbing (for IOP), and for each corneal location (for CT)] and comparison were then made between groups (allergic versus control) for differences in any observed effects.

RESULTS

Within groups, baseline mean IOPs in the allergic patient-group (14.2±3.0 mm Hg) and in the control group (13.1±1.9 mm Hg) were similar at all times, after eye rubbing (P >0.05, for all). The maximum reduction in IOP was 0.8 mm Hg in the control subjects and the maximum increase was also 0.8 mm Hg in the allergic subjects. Between groups (allergic versus control), the changes in IOP remained under 1 mm Hg at all times (P=0.2) after 30min of eye rubbing. Between 0 and 30min of CT measurements after eye rubbing, the mean central CT (CCT), inferior CT (ICT), superior CT (SCT), temporal CT (TCT) and nasal CT (NCT) did not vary significantly from baseline values in the control and allergic-subject groups (P>0.05, for both). Between both groups, changes in CT were similar at all locations (P>0.05) except for the TC which was minimally thinner by about 4.4 µm (P=0.001) in the allergic subjects than in the control subjects, 30min following 30s of eye rubbing.

CONCLUSION

IOP measured in allergic subjects after 30s of habitual eye rubbing was comparable with that obtained in normal subjects at all times between 0 and 30min. Although, CT in the allergic subjects were similar to those of the control subjects at all times, it varied between +10 and -7.5 µm following eye rubbing, with the temporal cornea showing consistent reductions in thickness in the subjects with allergy. However, this reduction was minimal and was considered to not be clinically relevant.

Factors influencing Saudi Arabian optometry candidates' career choices and institution of learning. Why do Saudi students choose to study optometry?

BACKGROUND

Optometry is a primary health-care profession (PHCP) and this study aimed to elucidate the factors influencing the choice of optometry as a career for Saudi students, the students' perceptions of optometry and the effect of gender.

METHODS

Two hundred and forty-seven students whose average age was 21.7 ± 1.5 (SD) years and who are currently enrolled in two colleges of optometry in Saudi Arabia--King Saud University (KSU) and Qassim University (QU)--completed self-administered questionnaires. The survey included questions concerning demography, career first choice, career perception and factors influencing career choices.

RESULTS

The response rate was 87.6 per cent and there were 161 male (64.9 per cent) students. Seventy-nine per cent of the participants were from KSU (males and females) and 20.6 per cent were from QU (only males). Seventy-three per cent come from Riyadh and 19 per cent are from Qassim province. Regarding the first choice for their careers, the females (92 per cent) were 0.4 times more likely (p = 0.012) to choose optometry than males (78.3 per cent). The males were significantly more likely to be influenced by the following factors: the Doctor of Optometry (OD) programs run at both universities, good salary and prospects (p < 0.05, for all). The women were significantly less likely to be influenced by another individual (p = 0.0004). Generally, more than two-thirds of the respondents viewed the desire to help others, professional prestige and the new OD programs as the three most influential factors in opting for a career in optometry.

CONCLUSION

Females were more likely to opt for a career in optometry and males were more likely to be influenced by the new OD programs, good salary and job prospects. Service provision to others in the community was a primary motivation to opt for a career in optometry among young Saudis.

Influence of age on measured anatomical and physiological interpupillary distance (far and near), and near heterophoria, in Arab males

PURPOSE

To compare the effects of age and near phoria on interpupillary distance measured at far (FIPD) and near (NIPD) using the Viktorin's and pupillometer (PD-5) methods.

METHODS

Interpupillary distance (IPD) by Viktorin's method and the corneal reflex pupillometer (PD-5) method, as well as near heterophoria by the Saladin near point card, were each obtained on 133 randomly selected normal subjects aged 20-67 years. Comparison within and between techniques, influence of age on IPD, and near heterophoria were assessed.

RESULTS

The mean FIPD varied significantly from the NIPD (P < 0.001 for both methods). Overall, FIPD ranged from 56-73 mm, and NIPD ranged from 50-70 mm. For FIPDs of 55 mm, 63 mm, and 71 mm, the corresponding NIPDs were less by 3.9 mm, 4.4 mm, and 5.0 mm, respectively, which were measured by Viktorin's method, and 4.0 mm, 4.6 mm, and 5.2 mm, respectively, measured by the PD-5 method. Between methods, the limits of agreement were: -3.9 mm and 3.2 mm (P > 0.05) for FIPD, and -3.1 mm and 2.9 mm (P > 0.05) for NIPD. Both IPDs varied significantly across age groups (P < 0.0001). Post hoc analysis revealed a significant variation (P < 0.01 in both techniques) only in the comparison between age groups 16-25 years and 41-67 years. The mean difference was -2.2 mm (-4.0 mm to -0.3 mm) and -2.8 mm (-4.7 mm to -1.0 mm) for Viktorin's method for FIPD and NIPD, respectively. For PD-5, the corresponding values were -1.3 mm (-3.2 mm to 0.4 mm) and -1.7 mm (-4.1 to -0.5 mm). Also, the near phoria differed significantly (P < 0.0001) across age groups and correlated positively with age (r(2) = 0.27, P < 0.0001) and NIPD (r(2) > 0.04; P < 0.03, both techniques).

CONCLUSION

The difference between FIPD and NIPD (about 4.4 mm in Arab males) was observed independent of the technique used. The Viktorin's and the PD-5 methods of IPD assessment resulted in similar values, and therefore, could be interchangeably used. However, caution is advised in cases of high power refractive corrections as the difference could vary from -4 mm to +3 mm (FIPD) and -3 mm to +3 mm (NIPD). Both IPDs have demonstrated an increase until the patients are in their early 40s, and a slight decrease has been observed thereafter. Age and NIPD were significantly associated with heterophoria in our subjects.