Dendritic Cell Density and Morphology Can Be Used to Differentiate Vernal Keratoconjunctivitis from Allergic Conjunctivitis.

The aim of the study was to compare the distribution of corneal and conjunctival epithelial dendritic cells (DCs) in vernal keratoconjunctivitis (VKC), allergic conjunctivitis (AC), and non-allergic controls to examine if the allergy type causes differences in immune cell activation. The prospective study included 60 participants: 20 with VKC, 20 with AC, and 20 non-allergic controls. In vivo confocal microscopy was performed on the right eye. The locations scanned included the corneal centre, inferior whorl, corneal periphery, corneal limbus, and bulbar conjunctiva. The DCs were counted manually, and their morphology was assessed for the largest cell body size, the presence of dendrites, and the presence of long and thick dendrites. The DC density was higher in VKC and AC compared to non-allergic group at all locations (p ≤ 0.01) except at the inferior whorl. The DC density in VKC participants was significantly higher than in AC at the limbus (p < 0.001) but not at other locations. Both the AC and the VKC group had larger DC bodies at the corneal periphery and limbus compared to the non-allergic group (p ≤ 0.03). The study found a higher proportion of participants with DCs exhibiting long dendrites at both the corneal periphery in AC (p = 0.01) and at the corneal centre, periphery, and limbus in VKC, compared to the non-allergic group (p ≤ 0.001). In conclusion, a higher DC density at the limbus may be a marker of more severe VKC. DCs with larger cell bodies and a greater proportion of participants with DCs displaying long dendrites can be potential markers to differentiate allergy from non-allergy, and more severe forms of allergy from milder forms.

Increased dendritic cell density and altered morphology in allergic conjunctivitis.

BACKGROUND: Corneal and conjunctival epithelial dendritic cells (DC) have an established role in vernal keratoconjunctivitis, however, their role in more prevalent forms of allergic eye disease remains unclear. This study evaluated corneal and conjunctival epithelial DC density, morphology, and distribution observed using in vivo confocal microscopy (IVCM) in allergic conjunctivitis. METHODS: In this prospective, observational study, 66 participants (mean age 36.6 ± 12.0 years, 56% female): 33 with allergic conjunctivitis and 33 controls were recruited. IVCM was performed at the corneal centre, inferior whorl, corneal periphery, corneal limbus, and temporal bulbar conjunctiva. DC were counted and their morphology was assessed as follows: largest cell body size, presence of dendrites, and presence of long and thick dendrites. Mixed model analysis (DC density) and non-parametric tests (DC morphology) were used. RESULTS: DC density was higher in allergic participants at all locations (p ≤ 0.01), (corneal centre median (IQR) 21.9 (8.7-50.9) cells/mm2 vs 13.1 (2.8-22.8) cells/mm2; periphery 37.5 (15.6-67.2) cells/mm2 vs 20 (9.4-32.5) cells/mm2; limbus 75 (60-120) cells/mm2 vs 58.1 (44.4-66.2) cells/mm2; conjunctiva 10 (0-54.4) cells/mm2 vs 0.6 (0-5.6) cells/mm2, but not at the inferior whorl 21.9 (6.2-34.4) cells/mm2 vs 12.5 (1.9-37.5) cells/mm2, p = 0.20. At the corneal centre, allergic participants had larger DC bodies (p = 0.02), a higher proportion of DC with dendrites (p = 0.02) and long dendrites (p = 0.003) compared to controls. CONCLUSIONS: Corneal and conjunctival DC density was increased, and morphology altered in allergic conjunctivitis. These findings imply that the ocular surface immune response was upregulated and support an increased antigen-capture capacity of DC in allergic conjunctivitis.

Dendritiform immune cells with reduced antigen-capture capacity persist in the cornea during the asymptomatic phase of allergic conjunctivitis.

BACKGROUND: Increased density and altered morphology of dendritic cells (DC) in the cornea and conjunctiva occur during active allergic conjunctivitis. This study investigated whether inflammation (characterised by altered DC density and morphology) persists during the symptom-free phase of allergic conjunctivitis. METHODS: Twenty participants (age 43.3 ± 14.3 years, 55% female) assessed during their active (symptomatic) phase of allergic conjunctivitis were re-examined during the asymptomatic phase. Ocular allergy symptoms and signs were evaluated during both phases, and five ocular surface locations (corneal centre, inferior whorl, corneal periphery, corneal limbus, and bulbar conjunctiva) were examined using in vivo confocal microscopy (HRT III). DC were counted manually, and their morphology was assessed for cell body size, presence of dendrites, presence of long dendrites and presence of thick dendrites using a grading system. Mixed model analysis (DC density) and non-parametric tests (DC morphology) were used to examine differences between phases. RESULTS: DC density at corneal locations did not change between the active and asymptomatic phases (p ≥ 0.22). However, corneal DC body size was smaller and fewer DC presented with long dendrites during the asymptomatic phase (p ≤ 0.02). In contrast, at the bulbar conjunctiva, DC density was reduced during the asymptomatic phase compared to the active phase (p = 0.01), but there were no changes in DC morphology. CONCLUSIONS: Dendritiform immune cell numbers persist in the cornea during the symptom-free phase of allergic conjunctivitis, whereas conjunctival DC appear to return to a baseline state. The morphology of these persisting corneal DC suggests their antigen-capture capacity is reduced during the asymptomatic phase.

Diurnal changes and topographical distribution of ocular surface epithelial dendritic cells in humans, and repeatability of density and morphology assessment.

PURPOSE: Dendritic cells (DC) play a crucial role in ocular surface defence. DC can be visualised in vivo by confocal microscopy but have not yet been fully characterised in humans. This study investigated the diurnal variation, topographical distribution and repeatability of DC density and morphology measurements. METHODS: In vivo confocal microscopy (IVCM) was conducted on 20 healthy participants (mean age 32.7 ± 6.4 years, 50% female) at baseline and repeated after 30 minutes, 2, 6 and 24 h. Images were captured at the corneal centre, inferior whorl, corneal periphery, limbus and bulbar conjunctiva. DC were counted manually, and their morphology was assessed for cell body size, presence of dendrites, and presence of long and thick dendrites. Mixed-model analysis, non-parametric analyses, Bland and Altman plots, coefficient of repeatability (CoR) and kappa were used. RESULTS: There were no significant changes in DC density (p ≥ 0.74) or morphology (p > 0.07) at any location over the 24-h period. The highest DC density was observed at the corneal limbus followed by the peripheral cornea (p < 0.001), with the lowest density at the corneal centre, inferior whorl and bulbar conjunctiva. Most DC at the corneal periphery, limbus and bulbar conjunctiva had larger cell bodies compared with the corneal centre (p ≤ 0.01), and the presence of long dendrites was observed mostly at non-central locations. Day-to-day CoR for DC density ranged from ±28.1 cells/mm2 at the corneal centre to ±56.4 cells/mm2 at the limbus. Day-to-day agreement of DC morphology determined by kappa ranged from 0.5 to 0.95 for cell body size, 0.60 to 0.95 for presence of dendrites, and 0.55 to 0.80 for the presence of long dendrites at various locations. CONCLUSIONS: No diurnal changes are apparent in corneal or conjunctival DC. Substantial topographical differences exist in DC density and morphology. IVCM provides good repeatability of DC density and acceptable agreement of DC morphology.

Corneal epithelial dendritic cells, tear neuropeptides and corneal nerves continue to be affected more than 12 months after LASIK.

PURPOSE: LASIK causes corneal nerve damage and may affect the neuro-immune crosstalk. This study examined the effects of LASIK on corneal epithelial dendritic cells (CEDC) density and morphology and explored their relationships with corneal nerves and tear neuropeptides. A grading system was developed to assess CEDC morphology. METHODS: Intra- and inter-observer repeatability of the CEDC morphology grading system was established using kappa (κ). In vivo confocal microscope images of the central cornea were captured from 20 participants who had undergone LASIK 12-16 months earlier and 20 controls (age 18-32 years, 55%F). CEDC density was counted manually, and CEDC morphology was assessed using a new grading system. CEDC sub-types (contacting nerves [CEDCc] and not contacting nerves [CEDCnc]) were also assessed. Differences in CEDC density and morphology were examined using mixed models and chi-squared test. Relationships between CEDC and corneal nerve parameters and tear substance P were explored using Spearman's correlation. RESULTS: Excellent intra- and inter-observer repeatability was demonstrated for the grading system (κ = 0.82-0.97). In post-LASIK participants, CEDC density was lower compared with controls (5 [0-34] vs. 21 [7-77] cells/mm2 ; p = 0.01), and the proportion of CEDC with thick dendrites was higher (55%-73% vs. 11%-21%, p < 0.003). Higher tear substance P levels were associated with higher CEDC density (rho = 0.48, p = 0.003). Fewer nerve interconnections were observed in participants in whom CEDC had dendrites (p = 0.03). CEDC sub-types followed a similar pattern to CEDC. CONCLUSIONS: The findings suggest that CEDC may remain altered more than 12 months post-LASIK. The association with substance P suggests a role for CEDC in corneal neurogenic inflammation.

Angle κ and its effect on the corneal elevation maps in refractive surgery candidates.

PURPOSE: To assess the associations of angle κ and Pentacam decentration indices with elevation maps in normal refractive surgery candidates. SETTING: Salouti Cornea Research Center, Salouti Eye Clinic, Shiraz, Iran. DESIGN: Retrospective observational study. METHODS: In this research, the right eyes of 173 refractive surgery candidates were assessed. Data of front and back corneal elevation maps, keratometric data, decentration indices, and corneal astigmatism obtained by Pentacam HR system and angle κ obtained by Orbscan IIz were extracted. Maximum elevation (or depression) for each of the 4 quadrants was recorded. Correlations of elevation values with angle κ, Pentacam decentration indices, keratometry, and astigmatism were examined by Pearson correlation coefficient. 148 age- and sex-matched cases with keratoconus grade 1 were selected as a positive control group, and Pentacam variables were compared between the groups. RESULTS: Overall, data from 173 eyes of 173 normal refractive surgery candidates and 148 eyes of 148 patients with keratoconus were recorded and analyzed. In normal refractive surgery candidates, the mean of angle κ was 5.32 ± 1.36 (SD) degrees. Angle κ had a positive correlation with front and back temporal elevations based on a best-fit sphere (BFS) ( r = 0.339, P = .001; r = 0.300, P < .001, respectively). Front and back keratometric astigmatisms were positively correlated with front and back nasal and temporal elevations ( r ≥ 0.543, P < .001) and negatively correlated with superior and inferior elevations ( r ≤ -0.547, P < .001). These associations no longer existed when using best-fit toric ellipse (BFTE) for calculating elevation data. The thinnest point to vertex decentration was significantly associated with the back temporal elevation (based on the BFTE) in both normal ( r = 0.311, P < .001) and keratoconus ( r = 0.190, P = .021) eyes. CONCLUSIONS: This study showed that elevation maps obtained by the Pentacam system using BFS might be affected by both the large angle κ and corneal astigmatism, confounding the preoperative assessment of refractive surgery candidates. Using BFTE as a reference for calculating elevation data should eliminate most diagnostic issues and thus is encouraged in this context.

The prevalence of refractive error in schoolchildren.

CLINICAL RELEVANCE: Information on the refractive error prevalence in school-aged children will result in delivering the optimal eye health service to this group. BACKGROUND: Understanding the prevalence of refractive error in school-aged children is crucial to reduce the consequences of uncorrected refractive error. This study aims to investigate the prevalence of refractive error among school-aged children in Shiraz, Iran. METHODS: In this cross-sectional population-based study, 2001 schoolchildren aged 6-12 years participated. All participants underwent cycloplegic refraction. Spherical equivalent (SE) of -0.50 dioptre or more was considered as myopia, SE of +2.00 dioptre or more as hyperopia, and astigmatism as cylinder power of 0.75 dioptre or more. The difference of 1.00 dioptre or more between two eyes defined as anisometropia. RESULTS: The prevalence of myopia was 11.6% (95% confidence interval [CI]: 10.2-13.1%), hyperopia 6.7% (95%CI: 5.6-7.9%), and astigmatism 28.9% (95%CI: 26.9-31.0%), out of which 82.1% had with the rule astigmatism. Anisometropia was detected in 4.0% (95%CI: 3.2-5.0%) of children. Astigmatism and anisometropia were significantly higher in boys (p < 0.001, p = 0.03 respectively). The SE decreased significantly with increasing age (p < 0.001) indicating an increase in myopia with age. In addition, the rate of myopic astigmatism increased with age (p < 0.001). Among studied schoolchildren 97.0% could achieve the best-corrected visual acuity of 6/6 and 3.0% could not in the better eye. CONCLUSION: Astigmatism was the most common refractive error among primary school children. The prevalence of myopia was relatively higher than other studies conducted in Iran, and it increased with age. These results may highlight the role of lifestyle changes and increased near work activities on the myopic shift in school-aged children. The findings provide information for screening programmes in school-aged children.

The Prevalence and Causes of Low Vision and Visual Impairment in School-Aged Children: The Shiraz Pediatric Eye Study.

Purpose: To determine the prevalence and causes of visual impairment (VI) in Shiraz schoolchildren aged between 6 and 12 years. Methods: In the present population-based study, stratified random sampling was used to select 2400 schoolchildren aged 6-12 years from all four educational districts of Shiraz, Iran. Using the definitions of the World Health Organization, VI was defined as best-corrected visual acuity (BCVA) ≤0.5 logMAR (20/60) in the better eye, and blindness as BCVA worse than 1.3 logMAR (20/400) in the better eye. The low vision was defined as BCVA equal to or worse than 0.5 logMAR (20/60) in either eye. Data were recorded from a detailed interview and ocular examination of each eligible student. Results: The mean age of the students was 9.1 ± 1.6 years. The prevalence of VI was 3/2001 (0.14%). The cause of VI in all these three patients (100%) was amblyopia due to high refractive errors (high ametropia and astigmatism). Regarding the main refractive errors leading to VI among these three patients, one patient had bilateral high hyperopia (compound hyperopic astigmatism), one of them had bilateral high astigmatism, and the other one had compound myopic astigmatism. According to a visual acuity of less than or equal to 20/60 in at least one eye, 9/2001 (0.4%) of children had low vision. Conclusions: This study revealed a low prevalence of VI in a sample of 6- to 12-year-old school-aged children. Amblyopia in the setting of high ametropia and astigmatism were the most common causes of VI.

Intraocular Pressure Changes after Water Drinking Test in Surgically Treated Primary Congenital Glaucoma.

PURPOSE: To assess intraocular pressure (IOP) changes after the water drinking test (WDT) in patients with primary congenital glaucoma (PCG). METHODS: In this prospective interventional study, 20 eyes of 20 patients with PCG were included. All patients had undergone trabeculotomy. Six out of twenty eyes had received a glaucoma drainage device (GDD) implantation. IOP was measured using an air-puff tonometer at baseline, and 15, 30, 45, and 60 min after WDT. The repeated-measures analysis of variance test was used to compare the mean IOPs at different time points. RESULTS: The mean ( ± standard deviation) of participants' age was 9.9 ± 2.7 years (range, 6 to 16 years), and 8 (40%) participants were male. The mean IOPs at baseline and 15, 30, 45, and 60 minutes after the WDT were 15.8 ± 3.7, 18.6 ± 3.4, 19.0 ± 3.8, 17.9 ± 3.8, and 16.9 ± 3.5 mmHg, respectively (P < 0.001). Pairwise comparisons revealed that the mean IOPs after 15 and 30 min were significantly greater than the baseline IOP (P < 0.001 and P = 0.002, respectively); however, the difference in mean IOPs after 45 and 60 min were not statistically significant from the baseline IOP. The averages of IOP peak and IOP fluctuation after the WDT were 20.0 ± 3.5 and 4.2 ± 2.9 mmHg, respectively. IOP fluctuation in those who underwent trabeculotomy alone was twice that of those with GDDs, but the difference was not statistically significant (5.0 vs 2.5 mmHg; P = 0.08). CONCLUSION: In patients with PCG, WDT induced significant IOP elevation 15 and 30 min after the test, which returned to pre-test values after 45 min.

Distribution of intraocular pressure in healthy Iranian children: the Shiraz Pediatric Eye Study.

PURPOSE: To describe the mean and normal range of intraocular pressure (IOP) and its associations in healthy Iranian school children using the noncontact tonometer. METHODS: In this cross-sectional study as part of the Shiraz Pediatric Eye Study, a stratified random sampling was performed among elementary school children of Shiraz, Iran. Basic demographics and socioeconomic status of households, past medical history, drug history, and eye health history were collected for each eligible student. Children underwent complete ophthalmic examination. Axial length, corneal curvature, and anterior chamber depth were measured using the IOL-Master 500. RESULTS: Of 2,001 eligible children, 1,901 (95.0%; 3,802 eyes) with a mean age of 9.1 ± 1.6 years (standard deviation; range, 6-12 years) had reliable IOP. The mean spherical equivalent refraction was 0.5 ± 1.3 D for the right eye and 0.6 ± 1.2 D for the left eye. Mean IOP in the right eye was 15.1 ± 2.5 mm Hg (median, 15.0; range, 8.0-27.0 mm Hg); in the left eye, 15.2 ± 2.5 mm Hg (median, 15.0; range, 9.0-28.0 mm Hg). In multiple regression analyses, the mean IOP was significantly lower among asthmatic children compared to normal participants (P = 0.007). The measured IOP was significantly higher in myopic participants than hyperopic patients (P = 0.003). CONCLUSIONS: This study provides a useful normative IOP database using the noncontact tonometer for healthy Iranian school children.

Density and Morphology of Corneal Epithelial Dendritic Cells are Different in Allergy.

Purpose: The role of corneal epithelial dendritic cells (CEDC), a subtype of antigen presenting cells, in ocular allergy remains largely unknown. This cross-sectional study evaluated the density and morphology of CEDC in participants diagnosed with systemic allergy, to increase our understanding of the role of CEDC in ocular inflammation associated with systemic allergy.Materials and methods: A convenience sample of 50 participants was categorised into allergic and non-allergic groups (31 allergic and 19 non-allergic) based on the results of skin prick test (SPT). Ocular allergy symptoms, clinical ocular surface signs and serum IgE were assessed. In vivo confocal microscopy was performed on the right eye only. The number of CEDC in a 1mm2 region at both the central and mid-peripheral cornea was manually counted. CEDC morphology was graded on a 1 to 3 scale.Results: Ocular surface symptoms, signs (other than eyelid oedema), and serum IgE were significantly higher in the allergic (SPT+) group. CEDC density at the mid-peripheral cornea was significantly lower in the allergic group (p = .003). CEDC morphology grades were significantly higher in allergic participants in the central cornea (p = .02), with the highest grade morphology observed only in allergic participants. No associations were evident between CEDC density or morphology and ocular signs, symptoms or serum IgE.Conclusions: The study showed reduced CEDC density and cells with longer dendrites in allergic participants. The more mature CEDC morphology in the allergic group is suggestive of an inflammatory or immune response.

The Shiraz Pediatric Eye Study; a Population Based Survey of School Age Children: Rationale, Design and Baseline Characteristics.

PURPOSE: To describe the rationale, study design, methodology, and baseline characteristics of the Shiraz Pediatric Eye Study, a population-based survey of schoolchildren in Shiraz, Iran. METHODS: This population-based study included schoolchildren aged 6-12 years from all four educational districts of Shiraz who were recruited in years 2015-2016. Stratified random sampling was used to select 2400 participants from all districts. Data were recorded from a detailed interview and ocular evaluation of each eligible student. The eye examination comprised uncorrected and best corrected visual acuity measurement, refraction, external eye examination (including specific strabismus and lid evaluation tests), slit lamp biomicroscopy, intraocular pressure measurement, the Ishihara color vision test, and stereoacuity. Exophthalmometry, optical biometry, and optical coherence tomography were performed for a randomly selected subset of children. General characteristics and socioeconomic variables were also recorded to assess risk factors. RESULTS: From a total of 2400 selected students, 2001 (83.3%) participated in the study. The mean age of the students was 9.1 ± 1.6 years, and 59.7% were girls. Most children had at least one parent with a diploma or less than diploma (63.5%), and 2.2% had illiterate parents. CONCLUSION: This study is expected to provide accurate estimates of the prevalence of visual impairments and their related determinants in Shiraz. In addition, it will identify children who should be targeted by blindness prevention programs.

Results for Water-drinking Test, before and after Laser Iridotomy, in Primary Angle-closure Suspects.

SIGNIFICANCE: Intraocular pressure and ocular biometric changes were similar before and after laser iridotomy in response to the water-drinking test in a cohort of patients at risk of angle closure. The water-drinking test does not seem to be a good provocative test to determine which eyes would benefit from a laser iridotomy. Our data call into question the preoperative predictive value of this test. PURPOSE: The aim of this study was to evaluate the effect of water-drinking test on intraocular pressure and ocular biometric parameters, before and after laser peripheral iridotomy, in patients with an occludable angle. METHODS: Twenty-seven patients, who met the inclusion criteria and had at least 180 degrees of iridotrabecular apposition, underwent a complete eye examination followed by the measurement of ocular biometric (using LenStar LS-900; Haag-Streit AG, Koeniz, Switzerland) and anterior chamber parameters (using Pentacam HR; Oculus Optikgerate GmbH, Wetzlar, Germany). All the measurements were repeated 30 minutes after the water-drinking test. Two weeks after laser peripheral iridotomy, all the measurements were repeated both before and after the water-drinking test. RESULTS: The mean ± SD of the age of the participants was 57 ± 9 years, and 23 (85.2%) were male. Intraocular pressure increased after the water-drinking test in both pre-laser peripheral iridotomy (17.0 vs. 19.3 mmHg, P < .001) and post-laser peripheral iridotomy (15.6 vs. 18.6 mmHg, P < .001) conditions. The thickness values of central cornea increased slightly after the water-drinking test in pre-laser peripheral iridotomy (535 vs. 538 µm, P = .001) compared with post-laser peripheral iridotomy (532 vs. 536 µm, P = .003). The water-drinking test had no significant effect on other biometric or anterior chamber parameters, before or after laser peripheral iridotomy. CONCLUSIONS: The water-drinking test increased intraocular pressure, both before and after laser peripheral iridotomy. Laser peripheral iridotomy had no significant effect on the amount of intraocular pressure change after the water-drinking test. The water-drinking test has no effect on other biometric or anterior chamber parameters.

The Water-Drinking Test Revisited: An Analysis of Test Results in Subjects with Glaucoma.

PURPOSE: The Water-Drinking Test (WDT) has been shown to predict the diurnal IOP change. This study evaluates the factors that may affect the WDT results. METHODS: This study was conducted on 203 glaucoma patients who had undergone trabeculectomy (53) or tube surgery (31), or had a medically controlled open-angle (82) or closed-angle (37) glaucoma. IOP was measured at baseline and then every 15 minutes over a one-hour period after drinking water. The main outcome measures were IOP change (increase in IOP from baseline) at all measurement time points, IOP peak (highest IOP after drinking water), IOP fluctuation (difference between IOP peak and baseline), and assessing the association of these IOPs with a patient's demographic and management modalities. RESULTS: The mean age of the participants was 54±18 years, and 113 (56%) were male. Female patients showed greater IOP fluctuation than males (7.28 vs. 5.92 mm Hg; P=0.016), and a greater IOP peak (22.7 vs. 20.1 mm Hg; P=0.001). The observed associations between gender and IOP changes were only significant in <50 years. IOP at 60 minutes was greater in tube than trabeculectomy (5.6 vs. 3.1 mm Hg; P=0.007). The number of topical medications showed a direct independent association with IOP changes (P<0.001). Compared to other classes of topical medications, latanoprost showed lower WDT-IOP profile (P=0.0003). CONCLUSIONS: WDT-IOP change was diminished in subjects on latanoprost, and was greater in females <50 years, and those on greater number of medications.

Water Drinking Test: Intraocular Pressure Changes after Tube Surgery and Trabeculectomy.

PURPOSE: To study the effects of filtration surgeries (tube and trabeculectomy) on changes in intraocular pressure after a water-drinking test. METHODS: In this prospective, non-randomized, comparative clinical study, 30 patients who had tube surgery and 30 age- and sex-matched trabeculectomy patients underwent a water-drinking test. Only one eye of each patient was included. The baseline intraocular pressure was ≤21 mmHg in all enrolled eyes with or without adjunctive topical medications. After the water-drinking test, the intraocular pressure was measured and recorded at 15, 30, 45, and 60 minutes and the results were compared between the two groups. RESULTS: In both groups, intraocular pressure significantly increased from baseline at all measured time-points (P < 0.001). In the trabeculectomy group, the average intraocular pressure increased from 14.8 ± 2.9 to 18.8 ± 4.7 mmHg at 30 minutes, but decreased at 60 min (18.0 ± 5.2 mmHg). In the Tube group, intraocular pressure increased incrementally until the last measurement (14.2 ± 3.9, 18.8 ± 5.6, and 19.7 ± 6.0 mmHg at baseline, 30, and 60 minutes, respectively). The end-pressure difference (intraocular pressure at 60 minutes vs. baseline) was significantly greater in the tube group (5.6 ± 3.6 mmHg; 41% change) than in the trabeculectomy group (3.2 ± 4.7; 23% change; P = 0.03). CONCLUSION: Intraocular pressure significantly increased after the water-drinking test in both the groups. Intraocular pressure started to decline 30 minutes after the water-drinking test in the trabeculectomy group, while it continued to increase up to 60 minutes in the Tube group. This finding may have implications regarding the efficacy or safety of the procedures in advanced glaucoma patients.

Agreement of Corneal Diameter Measurements Obtained by a Swept-source Biometer and a Scheimpflug-based Topographer.

PURPOSE: To assess the agreement between a swept-source optical biometry device (IOLMaster 700) and a Scheimpflug-based topography device (Pentacam HR) in measuring the corneal diameter. METHODS: A total of 100 eyes from 100 cataract surgery candidates were enrolled. The white-to-white (WTW) distance measurements provided by both devices were recorded and analyzed. A paired t test was performed to compare the mean values of the WTW distance between the IOLMaster 700 and Pentacam HR. The Bland-Altman analysis was used to evaluate the agreement between the measurements of both devices. RESULTS: Mean age (±SD) of the participants was 65.9 ± 3.3 years, and 58 (58%) were men. The mean WTW distances measured by the IOLMaster 700 and Pentacam HR were 11.72 ± 0.45 mm and 11.41 ± 0.42 mm, respectively (P < 0.001). The overall 95% limits of agreement were -0.17 and 0.78 mm. The 95% limits of agreement between the measurements of the 2 devices were -0.30 and 0.84 versus -0.07 and 0.72 for eyes with WTW distances of ≤11.50 mm versus >11.50 mm, respectively. CONCLUSIONS: According to the results of this study, the IOLMaster 700 may overestimate the WTW distance measurements by up to 0.78 mm compared with the Pentacam HR, so these 2 devices should not be used interchangeably for this purpose. The agreement is somehow weaker for eyes with WTW distances of 11.50 mm or less than those with WTW distances greater than 11.50 mm.

Correlation Between Intraocular Pressure and Central Corneal Thickness in Persian Children.

INTRODUCTION: This study aimed to determine intraocular pressure (IOP) and central corneal thickness (CCT) measurements in healthy Persian children to find clinical reference values in this ethnicity. Additionally, we examined the possible relationship between these measurements. METHODS: This cross-sectional study included 262 eyes of 131 Persian primary school children between 6 and 13 years of age. All eyes were healthy and had no anterior or posterior segment abnormalities, corneal disease, or evidence of glaucoma. Specular microscopy was used to measure CCT and both noncontact tonometry (NCT) and Goldmann applanation tonometer (GAT) were used to measure IOP. Correlations between IOP measurements were also examined. RESULTS: Mean CCT was 513.47 ± 34.51 µm in the right eye (OD) and 513.93 ± 33.88 µm in the left eye (OS). The CCT was not significantly different between older (10-13 years) and younger (6-9 years) patients. Mean IOP measured with GAT was 13.86 ± 2.13 mmHg OD and 13.72 ± 2.04 mmHg OS and mean IOP measured with NCT was 15.26 ± 2.38 mmHg OD and 15.11 ± 2.18 mmHg OS. The IOP and CCT measured with GAT were weakly correlated (OD: r = 0.141, P = 0.114; OS: r = 0.236, P = 0.007). However, IOP and CCT measured with NCT (OD: r = 0.487, P = 0.000; OS: r = 0.456, P = 0.000) were moderately correlated. Our outcomes demonstrated that for 100 µm increase in CCT, IOP measured with GAT and NCT increased by 0.8 and 3.3 mmHg, respectively, in OD and by 1.4 and 2.9 mmHg in OS. Based on intraclass correlation coefficients, IOP measurements made with GAT and NCT were in fair agreement in OD and in good agreement in OS. CONCLUSION: The IOP and CCT in healthy Persian school children (6-13 years old) were positively correlated. Our findings revealed that corneal thickness is thinner in Persian children than in most other racial groups. FUNDING: This study has been funded by deputy dean in research of School of Medicine and deputy vice chancellor of Shiraz University of Medical Sciences, Shiraz, Iran.

Comparison of keratometry measurements using the Pentacam HR, the Orbscan IIz, and the TMS-4 topographer.

PURPOSE: To compare and evaluate the agreement between keratometry readings using three devices: the Pentacam HR, the Orbscan IIz, and the TMS-4 topographer. METHODS: In this prospective comparative study, 115 eyes from 115 healthy refractive surgery candidates were sequentially examined using three devices. Fourier analysis was used to evaluate corneal astigmatism in these subjects. The outcome measures comprised steep and flat keratometry readings, corneal astigmatism, the mean keratometry reading, and the J0 and J45 components. Repeated-measures analysis of variance (RM-anova) and Bland-Altman plots with 95% limits of agreement were used to evaluate the difference between measurements. RESULTS: The mean keratometry readings were 43.89 ± 1.51, 43.52 ± 1.48, and 43.79 ± 1.50 D using the TMS-4 topographer, the Orbscan IIz, and the Pentacam HR, respectively (p < 0.001; RM-anova). The mean keratometric astigmatism was 1.27 ± 0.87, 1.20 ± 0.86, and 1.21 ± 0.82 D using the TMS-4 topographer, the Orbscan IIz, and the Pentacam HR, respectively (p = 0.007; RM-anova). The J0 measurements were higher using the TMS-4 topographer compared with the Orbscan IIz (p = 0.021; Bonferroni test). The mean, steep, and flat keratometry data were in better agreement using the TMS-4 topographer and the Pentacam HR. In general, the Orbscan IIz device measured lower values than either the TMS-4 topographer or the Pentacam HR. However, the corneal astigmatism measurements and the J0 component showed the best agreement using the TMS-4 topographer and the Orbscan IIz. CONCLUSIONS: The TMS-4 topographer and the Pentacam HR produced similar readings and can be used interchangeably to measure simulated keratometry values in young, healthy eyes. To measure corneal astigmatism, the TMS-4 topographer and the Orbscan IIz produced values that were similar and could be used interchangeably.