Anterior Chamber Angle Values Research Articles

Intraocular pressure increase after Nd:YAG laser capsulotomy and anterior segment optical coherence tomography analysis.

This study is to determine whether post-procedure intraocular pressure (IOP) increase is associated with the anterior chamber angle in cases of Neodymium: yttrium-aluminum garnet (Nd: YAG) laser capsulotomy. The study included 51 eyes with posterior capsule opacification. Initial IOP values of the patients were compared with IOP values without intraocular pressure-lowering administration at the end of the 1st hour, 1st day, 3rd day, and 7th day after Nd:YAG laser capsulotomy. The anterior segment angle configuration was evaluated using anterior segment optical coherence tomography analysis without dilatation before the procedure. The anterior chamber angle (ACA) and angle opening distances of 500 and 750 μm (AOD500 and AOD750) in the nasal and temporal quadrants were examined. The mean pre-laser IOP value only increased significantly at 1st hour post-laser (13.02 ± 3.02 mmHg vs 14.16 ± 4.07 mmHg, p = 0.016). In eyes with ACA below 40° in both the nasal and temporal quadrants, mean IOP increased significantly at 1st hour post-laser (p = 0.025 and p = 0.032, respectively), while it was not significant in eyes with ACA above 40° (p > 0.05). No correlation was found between ACA, AOD500, and AOD750 values and IOP changes at the first hour (p > 0.05). Except for the first hour after Nd:YAG laser capsulotomy, no significant increase in IOP was observed. This elevation was higher in eyes with ACA less than 40°. In patients with a narrow ACA, first-hour follow-up may be beneficial in terms of susceptibility to increased IOP.

Морфометрические особенности, характеризующие повышенный риск развития острого приступа закрытоугольной глаукомы у пациентов с осевой гиперметропией высокой степени, планирующих проведение рефракционной операции

Purpose. To study of quantitative and qualitative morphometric characteristics of the anterior chamber (AC) depth, lens thickness (LT), corneal-iris angle in young patients with high axial hyperopia planning refractive surgery. Material and methods. The main group – 35 patients (70 eyes) with high axial hyperopia. Inclusion criteria: absence of ophthalmic and systemic somatic pathology. The best corrected visual acuity (BCVA) is from 0.7 to 1.0. The comparison group included 35 patients (70 eyes) with primary closure of the anterior chamber angle (ACA) in combination with high hyperopia. Inclusion criteria: the presence of functional block of the ACA in at least 2 quadrants, the absence of signs of glaucomatous optic neuropathy. BCVA – from 0.6 to 0.9. All patients underwent gonioscopy of the ACA in 4 quadrants, optical coherence tomography, assessment of morphometric parameters of the anterior segment of the eyes. Results. The analysis of morphometric parameters revealed statistically significant differences in patients of the main group relative to the comparison group: in the AC depth in the central zone – 2.8 ± 0.3 vs. 2.4 ± 0.25 mm; LT – 4.0 ± 0.35 vs. 4.5 ± 0.3 mm; ACA width – 19.6 ± 4.4° vs. 13.1±5.1°; AC depth in the periphery – 1.0 ± 0.21 vs. 0.5 ± 0.37 mm, respectively. Next, we determined whether anyone from the main group had ACA values similar to the average values of this indicator of the comparison group (13.1 ± 5.1°): in 6 eyes of the main group (3 men aged 40 to 45 years) the values of the ACA turned out to be minimal, not significantly differing from the comparison group. In addition, in 7 eyes of 6 patients of the main group, the index of the AC depth in the periphery was less than 0.5 mm with normal values of the AC depth in the central zone, which was comparable with similar values in the comparison group. Conclusion. Among the examined patients with hyperopia at the age of 39 to 45 years, with axial length values from 19 to 22 mm, an increased risk of developing an acute angle-closure glaucoma occurred in 9 patients (26 %). Keywords: hyperopia; refractive surgery; acute angle-closure glaucoma

Evaluation of Eyelid, Angle, and Anterior Segment Parameters Using Scheimpflug Camera and Topography System in Obstructive Sleep Apnea Syndrome.

The purpose of the study was to investigate the eyelid hyperlaxity, anterior segment, and corneal topographic parameters in patients with obstructive sleep apnea syndrome (OSAS) using Scheimpflug camera and topography system. In this prospective and cross-sectional clinical study, 32 eyes of 32 patients with OSAS and thirty-two eyes of 32 healthy subjects were evaluated. The participants with OSAS were selected from those with an apnea-hypopnea index ≥ 15. The minimum corneal thickness (ThkMin), apical corneal thickness (ACT), central corneal thickness (CCT), pupillary diameter (PD), aqueous depth (AD), aqueous volume (AV), anterior chamber angle (ACA), horizontal anterior chamber diameter (HACD), corneal volume (CV), simulated K readings (sim-K), front and back corneal keratometric values at 3 mm, RMS/A values, highest point of ectasia on the anterior and posterior corneal surface (KVf, KVb), symmetry indices and keratoconus measurements were taken by combined Scheimpflug-Placido corneal topography and compared with healthy subjects. Upper eyelid hyperlaxity (UEH) and floppy eyelid syndrome were also evaluated. There were no statistically significant difference between groups in terms of age, gender, PD, ACT, CV, HACD, simK readings, front and back keratometric values, RMS/A-KVf and KVb values, symmetry indices, and keratoconus measurements (p>0.05). ThkMin, CCT, AD, AV, and ACA values were significantly higher in OSAS group compared to the control (p<0.05). UEH was detected in two cases in the control group (6.3%) and in 13 cases in the OSAS group (40.6%) and the difference was significant (p<0.001). The anterior chamber depth, ACA, AV, CCT, and UEH increase in OSAS. These ocular morphological changes occurring in OSAS may explain why these patients prones to normotensive glaucoma.

Short-term effects of two types of goggles on intraocular pressure and anterior eye segment biometrics

BackgroundTo evaluate and compare the changes in intraocular pressure and anterior eye segment biometrics during and after wearing two types of commonly used swimming goggles.MethodsIn a cross-sectional study, a total of 40 healthy adults aged between 18 and 60 years old were selected to wear two kinds of common swimming goggles (ocular socket and orbital goggles). Intraocular pressure and anterior segment biometry were evaluated before wearing, at 2 and 5 min of wearing, and at 5 min after removing the goggles. Intraocular pressure (IOP), corneal front keratometry values (K1, K2, Km), central corneal thickness (CCT), central anterior chamber depth (ACD), anterior chamber volume (ACV), and anterior chamber angle (ACA) were measured.ResultsThe IOP at 2 min (21.0 ± 2.2 mmHg) and 5 min (21.2 ± 2.3 mmHg) was significantly higher than before wearing goggles (17.7 ± 2.1 mmHg). The IOP after the goggles were removed and at 5 min after the goggles were removed was 18.4 ± 2.3 mmHg and 17.7 ± 2.1 mmHg, respectively. ACV, ACD, and ACA values all decreased while the googles were worn. After the goggles were removed, these changes gradually returned to baseline values, with no significant difference in the values before and after.ConclusionThis study proves that wearing orbital goggles can lead to an acute increase in IOP and a slight decrease in ACV, ACD, and ACA. However, once the goggles are removed, these indicators return to baseline levels, showing that wearing orbital goggles has no significant lasting effect on IOP and anterior segment parameters.

Pentacam changes in primary angle-closure glaucoma after different lines of treatment.

To assess the changes in the anterior chamber parameters using Pentacam following four different lines of treatment of primary angle-closure glaucoma (PACG). A retrospective comparative study included 126 patients (126 eye) presented within 24-48h after acute angle-closure glaucoma (AACG). Patients were divided into 2 groups: group A (68 eyes) with controlled intraocular pressure (IOP) ≤21 mm Hg, which included subgroup A1 (34 eyes) with clear lens underwent Nd:YAG laser peripheral iridotomy (LPI) and subgroup A2 (34 eyes) with cataract underwent standard phacoemulsification; and group B (58 eyes) with uncontrolled IOP, which included subgroup B1 (30 eyes) with clear lens underwent trabeculectomy and subgroup B2 (28 eyes) with cataract underwent combined phacoemulsification and trabeculectomy. Patients were followed up for at least 3mo. Primary outcomes were Pentacam anterior segment measurements [anterior chamber angle (ACA) and depth (ACD)]. Secondary outcomes were changes in IOP, visual acuity (VA) and recorded complications. At the 3rd month, there was significant increase in the ACA values in all studied groups compared to preoperative values (P<0.001). The highest percent of increase in ACA was recorded in phacotrabeculectomy group B2 (128.40%). There was significant increase in ACD values at 3rd month compared with baseline values (P<0.001) for groups A1, A2, and B2; without change in B1 trabeculectomy group. The maximum deepening of ACD was noticed in group B2 with 94.27% increase. Significant decrease in postoperative IOP in groups A2, B1 and B2 (P<0.001, P=0.014, and P<0.001 respectively). In group A1 there was significant increase in 3rd month postoperative IOP from baseline values (P<0.001). The maximum decrease in IOP was noticed in group B2 with 59.54% decrease. VA improvement in 3rd month postoperative was recorded in all studied groups, maximum VA improvement was observed in group B2 up to 0.2 logMAR. Pentacam can be a helpful tool in studying and comparing the effect of the different lines of management of PACG on the anterior chamber measures. Phacotrabeculectomy was proved to be an effective line for managing PACG with resultant significant increase in the anterior chamber parameters, IOP reduction as well as maximum VA improvement. LPI has only temporary effect on IOP with significant changes in ACA and ACD. Phacoemuslification alone can be an option in treating PACG. Trabeculectomy resulted in temporary increase in the anterior chamber parameter which subsequently returned to baseline values.

Using Anterior Segment Optical Coherence Tomography to Assess Angle Anatomy in Patients with Neurofibromatosis Type 1.

Lisch nodules have been identified in more than 90% of patients 16 years or older with neurofibromatosis type 1 (NF1). According to our hypothesis, the presence of Lisch nodules in patients with NF1 might affect the anterior chamber angle (ACA) parameters. The aim of this study was to evaluate the anterior segment angle parameters using anterior segment optical coherence tomography in patients with NF1. A total of 42 eyes from 21 patients with NF1 (study group) and 42 eyes from 21 age- and sex-matched healthy individuals (control group) were included in this study. Angle opening distance at 500 (AOD500) and 750 μm (AOD750) anterior to the scleral spur, ACA, and iris thickness (IT) values were measured in the temporal (T) and nasal (N) quadrants using anterior segment optical coherence tomography. The mean AOD500 and AOD750 values in both quadrants were significantly lower in the study group compared with the control group (T-AOD500: 548 ± 151 vs. 761 ± 288 [P < .001], T-AOD750: 705 ± 175 vs. 921 ± 334 [P < .001], N-AOD500: 599 ± 223 vs. 777 ± 292 [P = .002], and N-AOD750: 756 ± 268 vs. 948 ± 303 [P = .003], respectively). The mean ACA values in both quadrants were significantly narrower in the study group compared with the control group (T-ACA: 29.52 ± 6.36 vs. 40.83 ± 8.90 [P < .001] and N-ACA: 30.05 ± 7.11 vs. 41.29 ± 8.68 [P < .001], respectively). The IT values in both quadrants were significantly thicker compared with the control group (T-IT500: 406 ± 78 vs. 355 ± 59 [P = .001], T-IT750: 453 ± 103 vs. 362 ± 100 [P < .001], N-IT500: 416 ± 93 vs. 353 ± 54 [P < .001], and N-IT750: 437 ± 91 vs. 370 ± 95 [P = .002], respectively). We have revealed lower angle opening distance values in individuals with NF1 than in the healthy ones, as well as significantly narrower ACA values and significantly thicker IT values.

Pregnancy and the eye. Changes in morphology of the cornea and the anterior chamber of the eye in pregnant woman.

The main goal of the study was to determine whether uncomplicated pregnancy and natural labor exert influence on the cornea and the anterior chamber of the eye. The study included 114 eyes of 57 women in age of 21-35 years old. Only patients in the physiological pregnancy and giving natural birth were recruited into study. Prospective observative examination was performed. Patients were diagnosed twice: in 36 HBD and 6 weeks after labor. Using the Scheimpflug camera (Pentacam system) the following parameters were assessed: central corneal thickness (CCT), keratometric parameters: flat (K1) and steep (K2), astigmatism value and axis, anterior chamber depth (ACD), anterior chamber volume (ACV) and anterior chamber angle (ACA). The statistical analysis was carried out in the StatSoft Statistica 13 program. CCT value is greater in the third trimester than in 6th week after the labour. ACD and ACA values are higher in 36 HBD than in the post-partum period but the difference is not statistically important (p > 0.05). K1, K2, cylindrical refraction error, axis of cylindrical refraction error do not change. Authors claim that it is the result from an increase in water retention in the corneal stroma as a response to hormonal changes. The plasticity of the anterior chamber seen before delivery can be a natural adaptive mechanism of the female body, which counteracts the excessive increase in intraocular pressure in the second stage of delivery.

Stabilization Time of Anterior Segment Parameters After Trabeculectomy Surgery

To investigate the postoperative changes in the anterior segment parameters by Scheimpflug imaging method in patients undergoing trabeculectomy surgery. This prospective study included 38 phakic eyes of 38 patients with primary open-angle glaucoma who underwent trabeculectomy. Anterior chamber angle (ACA), anterior chamber depth (ACD), anterior chamber volume (ACV), and central corneal thickness (CCT) of the eyes were measured by performing Scheimpflug imaging in preoperative (baseline) and postoperative periods (1st week and 1st, 3rd, and 6th months after the surgery). Significant differences were observed in all the anterior segment parameters during the postoperative period (P<0.001 for ACA, ACD, and CCT; P=0.001 for ACV). Compared with preoperative values, ACA, ACD, and ACV values decreased and CCT value increased in the 1st postoperative week (P<0.001 for all the parameters). Compared with the 1st postoperative-week values, ACA, ACD, and ACV values significantly increased and CCT value significantly decreased in the 1st postoperative month (P=0.002 for ACV; P<0.001 for ACA, ACD, and CCT). However, no significant differences were observed between the baseline and 1st postoperative-month values (P>0.05 for all the parameters). Moreover, the changes in the anterior segment parameters were not statistically significant after the 1st postoperative month. Our results showed that the changes in the anterior segment parameters observed in the early postoperative period after trabeculectomy returned to their baseline values after approximately 1 month after the surgery and remained stable thereafter.

Anterior chamber indices in a population-based study using the Pentacam.

To determine the distribution of anterior chamber depth (ACD), anterior chamber volume (ACV), and anterior chamber angle (ACA) values in a rural population over 5years of age using the Pentacam. In this cross-sectional study, samples were selected from over 1-year-old inhabitants of two villages in Iran using a multistage cluster sampling approach. All participants underwent the measurement of uncorrected and corrected visual acuity and auto-refraction, retinoscopy, subjective refraction, and slit lamp examination. Finally, corneal imaging was done for all subjects over 5years of age using the Pentacam. Of 3851 selected individuals, 3314 participated in the study, of whom 2681 met the inclusion criteria. The mean age of the sample was 36.03 ± 18.5years (range 6-90years). The mean ACD, ACA, and ACV values were 3.37mm (95% CI: 3.37-3.39), 34.82° (95% CI: 34.45-35.2), and 159.17µL (95% CI: 156-161.36), respectively. The results of multiple linear regression models showed that ACD, ACA, and ACV values reduced with age, and ACD and ACV values were significantly higher in males. ACA and ACV values correlated inversely with central corneal thickness, while the ACA value correlated directly with keratometry and inversely with the ACV value. This study is one of the few studies in the world showing changes in ACD values in different age groups using the Pentacam. According to the results, aging was associated with a decline in the mean ACD, ACA, and ACV values. These parameters were the largest in patients with emmetropia and smallest in hyperopic subjects.

Distribution of Anterior Chamber Parameters in Normal Chinese Children and the Associated Factors.

To describe the distribution of anterior chamber depth (ACD), anterior chamber volume (ACV), and anterior chamber angle (ACA) and establish the associated factors in the pediatric population in Shanghai, China. In this cross-sectional study, children aged 6 to 18 years from 9 primary and middle schools in Shanghai were enrolled. The Pentacam Scheimpflug camera was used to measure anterior eye chamber parameters. The distribution of ACD, ACV, ACA, and their associations with age, sex, body mass index, cycloplegic refractive error, axial length, intraocular pressure, and other parameters were analyzed. A total of 1321 children were included, with a mean age of 9.65±2.95 years. The mean ACA, ACD, and ACV values were 37.95±7.96 degrees, 3.22±0.23 mm and 194.89±28.95 mm, respectively, and were higher in boys than in girls. ACV and ACD had similar growth trend curves with age, whereas ACA was stable. Overall, 5% of the tested children had ACA values ≤24.91 degrees. Greater ACV, deeper ACD, shorter pupil diameter, shorter axial length, and thinner apex corneal thickness were the independent factors associated with wider ACA (R=13.0%, P<0.001). As one of diagnostic indicators of angle closure, ACA was stable with age. The results of this study should improve the current understanding of the distribution of anterior chamber parameters and the main factors affecting their variation.

Evaluation of Anterior Segment Changes of Patients Taking Alpha1-Blockers by Ultrasound Biomicroscopy in the Drug-free Period.

Objectives:To evaluate and compare anterior segment changes in patients taking alpha-1 (α1) blockers (tamsulosin, terazosin, doxazosin, alfuzosin) for benign prostatic hypertrophy, during drug intake and drug-free period, using ultrasound biomicroscopy (UBM).Materials and Methods:In this prospective study, UBM was done before and after pupil dilatation in 31 phakic eyes of 19 male patients taking α1-blockers. Undilated and dilated UBM was repeated before cataract extraction, after stopping the drug for 10 days. On ideal images, pupil diameter (PD), anterior chamber depth (ACD), anterior chamber angle (ACA), and angle opening distances at points 500 µm and 250 µm from the scleral spur (AOD500 and AOD250) values were noted and changes in parameters were evaluated to reveal any changes that occurred after discontinuing the drug. No patient in the study was previously or currently using any other α1-adrenergic antagonist medication. Exclusion criteria for all patients included a history of diabetes mellitus, systemic hypertension, glaucoma, pseudoexfoliation syndrome, chronic use of medicated eye drops, and previous ocular surgery.Results:PD, ACD, ACA, AOD500 and AOD250 values measured before pupil dilatation in the drug-free period were not significantly different from those measured during α-blocker intake (p>0.05). In dilated eyes, the mean value of AOD500 was 0.35±0.08 mm during drug usage and 0.39±0.08 mm in the drug-free period. The mean value of AOD250 was 0.23±0.06 mm during drug usage and 0.26±0.07 mm after discontinuation. These increments were statistically significant (p<0.05, z=-3.699, z=-2.984). On the other hand, there were no significant differences in ACD, ACA, or PD values in dilated eyes after discontinuing α1-blockers (p>0.05).Conclusion:The interruption of taking α1-blockers in patients who have benign prostatic hypertrophy does not seem to influence anterior segment parameters generally. However, further investigation is needed.

Laser peripheral iridotomy changes anterior chamber architecture.

The pressure gradient between anterior and posterior chamber in acute angle closure (AAC) and primary angle closure suspects is balanced by a sufficient laser peripheral iridotomy (LPI). The anterior chamber changes induced by LPI in patients with unilateral AAC were examined and compared to healthy eyes to define threshold values, which may help to discriminate between healthy and diseased eyes. Using Scheimpflug photography, anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), and central corneal thickness (CCT) were measured before and after LPI in both eyes of unilateral AAC cases. These measurements were compared to a group of healthy control eyes to determine threshold values for ACD, ACV, and ACA. The ACD, ACV, and ACA increased significantly in the 25 AAC eyes after LPI. The ACD, ACV, ACA, and CCT values in the AAC eyes obtained before LPI were compared to a control group of 59 healthy eyes with wide open chamber angles. The cutoff values revealed by receiver operating characteristic analysis were 2.1 mm for ACD, 90.5 mm2 for ACV, and 27.25° for ACA. Our results confirm the significant changes of the anterior segments architecture induced by LPI in AAC eyes. The found threshold values for ACD, ACV, and ACA may help in daily clinical routine to discriminate between healthy eyes and those in need for a prophylactic LPI.

Dynamic changes in optic disc morphology, choroidal thickness, anterior chamber parameters, and intraocular pressure during Valsalva maneuver.

To investigate the effects of the Valsalva maneuver (VM) on optic disc morphology, choroidal thickness, and anterior chamber parameters. This prospective observational study included 60 eyes of 60 healthy subjects. The anterior chamber parameters, including central corneal thickness (CCT), anterior chamber depth (ACD), anterior chamber angle (ACA), anterior chamber volume (ACV), pupil diameter (PD), axial length (AL), subfoveal and peripapillary choroidal thickness, optic disc parameters, and intraocular pressure (IOP), were measured at rest and during VM. VM did not have any significant influence on AL, subfoveal and peripapillary choroidal thickness, optic disc area, rim area, cup area, cup-to-disc area ratio, vertical cup-to-disc ratio, rim volume, cup volume, and nerve head volume measurements (for all; p >0.05). IOP and PD significantly increased during VM (for both; p <0.001). VM significantly decreased CCT, ACD, ACA, and ACV values (for all; p <0.001). Moreover, the optic nerve cup volume decreased and the horizontal cup-to-disc ratio significantly increased during VM (for both; p <0.05). VM may cause transient changes in IOP, optic disc morphology, and anterior chamber parameters.

Effect of Fasting on Corneal Biomechanical and Structural Parameters

ABSTRACT Purpose: To evaluate the effects of hunger and thirst on corneal biomechanical and structural parameters during Ramadan fasting. Materials and Methods: Corneal biomechanical properties and intraocular pressures of 29 eyes of 29 healthy subjects were evaluated by Reichert ocular response analyzer; and structural and anatomical properties of cornea and anterior eye chamber of same eyes were scanned with Oculus Pentacam anterior segment analyzer. Each eye has been evaluated at 8 am and 4 pm both during and 1 month after Ramadan. Changes of subjects’ weight were calculated and their relationship with corneal biomechanical and structural parameters was assessed. Results: Intraday changes in horizontal corneal astigmatism (p = 0.02), anterior chamber volume (p = 0.01), intraocular pressure associated with the Goldmann IOPg (p = 0.02) and corneal resistance factor (CRF) (p = 0.04) were significantly different when measured during the fasting period in Ramadan and 1 month thereafter. Moreover, when we compared 8 am measurements taken during and after Ramadan, we observed significant differences for anterior chamber volume (p = 0.04) and anterior chamber angle values (p = 0.03). Similarly, for 4 pm measurements, there were significant differences for IOPg (p = 0.01) and CRF values (p = 0.00). Conclusions: Fasting lasting for more than 12 h during Ramadan creates an important window of opportunity to investigate the response of anterior chamber of eye to hunger and thirst. The current study contributes to the existing literature on the effects of dietary habits and water intake on corneal and anterior chamber properties.

The effect of pharmacologic pupillary dilatation on anterior segment parameters in patients with exfoliation syndrome

PurposeThe purpose of this study was to evaluate the effect of pharmacologic pupillary dilatation on anterior chamber depth (ACD) and anterior chamber angle (ACA) in eyes with exfoliation syndrome (XFS). MethodsThirty-six eyes of 36 patients with XFS were evaluated with slit-lamp examination, Goldmann applanation tonometry and ultrasound biomicroscopy (UBM) under standard light conditions. Primary outcome parameters were defined as the change in ACD and ACA measured before and 40min after instillation of a single drop of either 1% cyclopentolate (Group I; n=12), 2.5% phenylephrine (Group II; n=12) or 1% tropicamide (Group III; n=12). Change in intraocular pressure (IOP) during the same time interval was included as a secondary outcome measure. ResultsThe average predilatation ACD, ACA and IOP values in the study subjects were 2.54±0.40mm, 27.9±6.3° and 14.9±3.1mmHg, respectively. There were no significant differences in the mean age (p=0.461), the female/male ratio (p=0.232), baseline ACD (p=0.841), ACA (p=0.761) or IOP (p=0.070) within the three groups. Differences in dilation induced changes in ACD (p=0.108), ACA (p=0.636) and IOP (p=0.160) between the three groups were not statistically significant. ConclusionPupillary dilatation with a single drop of 1.0% cyclopentolate, 2.5% phenylephrine or 1% tropicamide is not associated with shallowing of the anterior chamber or narrowing of the ACA in patients with XFS who present with open angles.

Evaluation of anterior segment parameters using pentacam in silicone oil-injected patients after pars plana vitrectomy

Background:The aim of this study is to evaluate anterior segment changes with Pentacam Scheimpflug camera after pars plana vitrectomy (PPV) and silicone oil injection.Materials and Methods:In all, 44 eyes of 44 patients who underwent PPV by one surgeon were evaluated with Pentacam preoperatively, first week, and first month after surgery. The patients were divided into two groups, eyes with silicone injection after PPV and eyes with PPV and no endotamponade. Main outcome measures were preoperative and postoperative anterior chamber volume (ACV), anterior chamber depth (ACD), anterior chamber angle (ACA), and central corneal thickness (CCT) obtained with pentacam.Results:Each group consisted of 22 patients. In both groups no significant difference was detected among preop and postop changes in ACV and ACA values (P > 0.05). The increase in ACD in silicone oil–injected group and the decrease in ACD in PPV group at postop 1 week were statistically significant (P < 0.05). The increase in CCT in silicone oil–injected group at postop 1 week and then decrease in postop 1 month were also significant (P < 0.05). Surgically induced astigmatism (SIA) was 3.7 Dioptry (D) in silicone oil–injected group and 2.4 D in PPV group at postop 1 week. SIA decreased to 1.7 D and 1.5 D, respectively, at postop 1 month. Changes in SIA were significant (P < 0.05).Conclusion:PPV effects cornea and anterior segment. Changes in cornea and anterior segment after PPV seem to return to preoperative values among 1 month after surgery.

Anterior segment biometry using ultrasound biomicroscopy and the Artemis-2 very high frequency ultrasound scanner

PurposeTo compare the precision of anterior chamber angle (ACA) and anterior chamber depth (ACD) measurements taken with ultrasound biomicroscopy (UBM) and the Artemis-2 Very High Frequency Ultrasound Scanner (VHFUS) in normal subjects.DesignProspective study.MethodsWe randomly selected one eye from each of 59 normal subjects in this study. Two subjects dropped out of the study; the associated data were excluded from analysis. ACA and ACD measurements were obtained using the VHFUS and the UBM. The results were compared statistically using repeated-measures analysis of variance for the intraobserver repeatability, unpaired t-test, and limits of agreement.ResultsThe average ACA values for the UBM and the VHFUS (±standard deviation) were 41.83° ± 5.03° and 33.36° ± 6.03°, respectively. The average ACD values were 2.96 ± 0.34 mm and 2.87 ± 0.31 mm. The intraobserver repeatability analysis of variance P-values for ACA and ACD measurements using UBM were 0.10 and 0.68, respectively; for the Artemis-2 VHFUS, the respective values were 0.68 and 0.09. The difference in ACA measurements was statistically significant (t = 8.41; P < 0.0001), while the difference in ACD values was not (t = 1.51; P < 0.13). The mean ACA difference was 8.50° ± 2.50°, and the limits of agreement were +13.30° to −3.60°. The mean ACD difference was 0.09 ± 0.27 mm, and the limits of agreement ranged from 0.61 mm to −0.43 mm. The mean difference percentage of ACD was 3.1% for both instruments.ConclusionIn case of the ACD, both instruments can be used interchangeably; however, with the ACA instruments, they cannot be used interchangeably.

Effects of pterygium surgery on front and back corneal surfaces and anterior segment parameters

The purpose of this study was to evaluate the effects of pterygium surgery on front and back corneal surfaces and anterior segment parameters. This prospective study included 96 eyes with primary pterygium that underwent surgery. Preoperatively and at 1, 3, and 6 months postoperatively, Pentacam was used to evaluate front and back corneal surfaces, anterior chamber depth (ACD), anterior chamber angle (ACA) and anterior chamber volume (ACV). Mean simulated keratometry at the front corneal surface increased from 42.73 ± 2.21 D preoperatively to 44.45 ± 2.05 D at 1 month (P < 0.001); it then decreased to 44.32 ± 2.07 D at 3 months (P < 0.001) and 44.19 ± 2.10 D at 6 months (P = 0.01). There was no statistically significant change in mean simulated keratometry at the back corneal surface. Radius of the front corneal best-fit sphere (BFS) decreased from 7.99 ± 0.29 mm preoperatively to 7.77 ± 0.25 mm at 1 month postoperatively (P < 0.001), without further change up to 6 months. Radius of the back corneal BFS increased from 6.42 ± 0.24 mm preoperatively to 6.50 ± 0.24 mm at 1 month (P < 0.001), without further change. Postoperative changes in mean simulated keratometry and radii of BFS had statistically significant positive correlations with pterygium extension onto the cornea and grade of pterygium morphology but, not with the surgical technique. There were no significant changes in ACD, ACA, and ACV values after pterygium surgery. Furthermore, the spherical equivalent of manifest refraction changed from +0.75 ± 1.06 D preoperatively to -0.72 ± 1.33 D at 1 month postoperatively (P = 0.001), with no further significant change. In conclusion, after pterygium surgery there were significant changes in front mean keratometry and front and back corneal radii of BFS. These were correlated with preoperative pterygium size and morphology grade. No significant changes in anterior segment parameters were noted postoperatively.

Evaluation of anterior segment parameter changes using the Pentacam after uneventful phacoemulsification

This study set out to evaluate the influences of uneventful phacoemulsification on the anterior segment parameters obtained with the Pentacam rotating Scheimpflug camera and intraocular pressure (IOP). A total of 42 eyes of 34 patients (26 men, eight women) were evaluated preoperatively, and at 1, 3 and 6 months postoperatively with the Pentacam. Intraocular pressure was measured with the Goldmann applanation tonometer. The non-parametric paired t-test was used to compare preoperative and 1-, 3- and 6-month postoperative measurements of anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA) width, central corneal thickness (CCT), the central 3-, 5- and 7-mm corneal volume (CV), pupil size, and IOP. Pearson's correlation test was used to evaluate the relationships between IOP and ACD, ACV and ACA width. The differences between ACD, ACV, ACA and IOP values taken preoperatively and those taken postoperatively at 1, 3 and 6 months were statistically significant (p<0.05). The differences between CCT, central 3-, 5- and 7-mm CV, and pupil size measurements taken preoperatively and those taken postoperatively at 1, 3 and 6 months were not statistically significant (p>0.05). The decrease in IOP was not correlated with the changes in ACD, ACV and ACA (p>0.05). Uneventful phacoemulsification significantly reduced IOP, increased ACD and ACV, and widened the ACA. However, alterations in CV, CCT and pupil size values were not statistically significant. Alterations in ACD, ACV, ACA and IOP remain stable after the first month of surgery.

Changes in intraocular pressure and anterior segment morphometry after uneventful phacoemulsification cataract surgery

To study changes in anterior segment morphometry after uneventful phacoemulsification cataract surgery, and to investigate whether there is a relationship between any observed changes and intraocular pressure (IOP) reduction after the procedure. The anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), central corneal thickness (CCT), and IOP were measured in 101 non-glaucomatous eyes before and after uneventful phacoemulsification cataract surgery. After cataract surgery, the mean ACD, ACV, and ACA values increased by 1.08 mm, 54.4 mm(3), and 13.1 degrees , respectively, and the mean IOP (corrected for CCT) decreased by 3.2 mm Hg. The predictive value of a previously described index (preoperative ACD/preoperative IOP (corrected for CCT) or CPD ratio) for IOP (corrected for CCT) reduction after cataract surgery was confirmed, reflected in an r(2) value of 23.3% between these two parameters (P<0.001). Other indices predictive of IOP reduction after cataract surgery were also identified, including preoperative IOP/preoperative ACV and preoperative IOP/preoperative ACA, reflected in r(2) values of 13.7 and 13.7%, respectively (P<0.001 and P<0.001, respectively). Our study confirms the predictive value of the CPD ratio for IOP reduction after cataract surgery, and may contribute to the decision-making process in patients with glaucoma or ocular hypertension. Furthermore, two novel indices of preoperative parameters that are predictive for IOP reduction after cataract surgery were identified, and enhance our understanding of the mechanisms underlying IOP changes after this procedure.