Changes In Anterior Chamber Volume Research Articles

Changes in anterior chamber biometry and intraocular pressure after uneventful phacoemulsification in non-glaucomatous eyes.

In non-glaucomatous eyes, many factors impact intraocular pressure (IOP) reduction following phacoemulsification. This study aimed to determine the relationship between changes in IOP and alterations in anterior chamber biometric measurements using the Pentacam Scheimpflug anterior segment imaging system before and after uneventful phacoemulsification in non-glaucomatous eyes. This prospective interventional study included patients with ages of 20 - 80 years, no known systemic diseases, and visually significant cataracts necessitating phacoemulsification with posterior chamber intraocular lens implantation. The preoperative and two-month postoperative IOPs were measured using a Goldmann applanation tonometer, and the iridocorneal angle (ICA) in four quadrants (superior, inferior, nasal, and temporal), anterior chamber depth (ACD), and anterior chamber volume (ACV) were measured using the Pentacam. Forty-two eyes of 42 patients with a mean (standard deviation [SD]) age of 56.8 (10.7) years were included; 22 (52%) were men and 20 (48%) were women. The eyes demonstrated statistically significant changes in postoperative IOP, ACD, ACV, and in widening of the ICA (all P < 0.05), with a mean (SD) IOP reduction of 4.5 (2.7) mmHg, ACD deepening of 0.7 (0.6) mm, ACV increase of 33.2 (21.1) mm3, and ICA widening of 7.5o (6.4o), 12.4o (7.7o), 9.1o (7.1o), and 11.5o (6.1o) in the superior, inferior, temporal, and nasal quadrants, respectively. A significant positive correlation was detected between pre- and postoperative IOP (r = + 0.58; P < 0.001) and between pre- and postoperative ACD (r = + 0.50; P < 0.001). Significant negative correlations were detected between preoperative ACV and changes in ACV (r = - 0.42; P < 0.001) and between preoperative ICA and changes in ICA (r = - 0.02; P = 0.001). However, no significant correlations were observed between the changes in IOP and patient age (r = + 0.001; P = 0.957) and axial length of the eye (r = + 0.13; P = 0.221), or changes in ICA (r = - 0.01; P = 0.945), ACD (r = + 0.01; P = 0.945), and ACV (r = - 0.12; P = 0.599). We observed a significant reduction in IOP, widening of the ICA, and increases in ACD and ACV after phacoemulsification; however, there was no significant correlation between changes in IOP and other biometric variables. Further studies are required to determine the exact mechanisms underlying these effects.

Relationship Between Optical Coherence Tomography and Anterior Chamber Depth After Pupillary Dilation in Primary Angle Closure Suspects.

Anterior chamber depth (ACD) change after pupillary dilation is correlated with lens vault (LV) and anterior chamber width (ACW), as observed by swept-source optical coherence tomography (SS-OCT) at both horizontal and vertical scans in patients with primary angle closure suspect and cataract. The purpose of this study is to evaluate the association between ACD and other anterior chamber parameters after pharmacological dilation in patients with primary angle closure suspect and cataract. SS-OCT was performed for 78 patients at baseline and 1 hour after pharmacological dilation. Measurements were taken at 8 evenly spaced axes at 250, 500, and 750μm from the scleral spur. Pearson correlation coefficient (ρ) was used to evaluate the relationship between averaged ACD change and other SS-OCT parameters. Multivariable regression analyses were performed to determine the parameters that predict ACD change. Across all 14 dimension and angle parameters, 12 parameters at the 270-degree axis and 10 parameters at the 0-degree axis yielded significant correlations with ACD change (ρ=0.24-0.55, P <0.05). Angle parameters were most significantly correlated to ACD change 750µm from the scleral spur. The prediction model for ACD change after pharmacological dilation at 0 degree included decreased LV, wider ACW, and increased trabecular iris space area (all P ≤0.001). The prediction model for ACD change at 270 degrees included: decreased LV, wider ACW, larger change in anterior chamber volume, larger baseline anterior chamber volume, and smaller baseline angle opening distance (all P ≤0.03). LV and ACW, as measured in both vertical and horizontal scans, were found to be determinants of the ACD change after pharmacological pupillary dilation. Examination of these parameters may help identify patients at higher risk of developing angle-closure disease.

Changes in Anterior Chamber Volume, Depth and Angle After Prophylactic Laser Peripheral Iridotomy in Patients With Primary Angle-closure Suspect

Background and Objectives This study aims to assess changes in anterior chamber parameters after prophylactic laser peripheral iridotomy (LPI) in patients with primary angle-closure suspect (PACS). Subjects and Methods In this study, 43 patients (86 eyes) with PACS (Mean age: 55.16±9.14 years) participated. The anterior chamber parameters including anterior chamber volume (ACV), anterior chamber angle (ACA) and central anterior chamber depth (CACD) were extracted from the Pentacam map at 0-180° meridian before and one month after prophylactic LPI. Results The only parameter that had a significant increase after LPI was ACV, which increased from 99.26±19.57 mm3 to 113.09±19.712 mm3 after LPI (P&lt;0.001). The relationship between age and ACV changes after LPI was statistically significant (P=0.014), indicating that the increase of age is associated with the increased of ACV after LPI. The relationship of ACV and ACD with their initial values was statistically significant, such that with the increase of the initial values of ACV and ACD, their changes decrease. Due to the lack of significant increase in CACD after LPI, the relationship between its changes after LPI and its initial value cannot be relied upon. Conclusion ACV is the only anterior chamber parameter that changes significantly after prophylactic LPI. This parameter can be used as a measurable scale to evaluate and monitor the eyes of patients with PACS. Among the PACS cases, older patients and patients with lower initial ACV have greater increase of ACV after LPI

Correlation between corneal refractive power and anterior chamber morphology in age-related cataract patients with shallow anterior chambers

Objective: To investigate the relationship between corneal refractive power and anterior chamber parameters in age-related cataract patients with normal axial lengths and shallow anterior chambers. Methods: Retrospective case series study. Clinical data of 627 age-related cataract patients (627 eyes) with axial lengths between 22 mm and 24 mm and anterior chamber depths less than 2.20 mm treated in the Department of Ophthalmology of Peking University International Hospital from June 2018 to October 2021 were selected. There were 215 male patients and 412 female patients, with an average age of (75±10) years. According to the average corneal refractive power, eyes were divided into groups of keratometry (K)<42 diopters (D) (50 eyes), 42 D ≤K<45 D (398 eyes) and K ≥45 D (179 eyes). Axial length, anterior chamber depth, corneal diameter, anterior chamber volume and anterior chamber angle of 3 groups were recorded, and Spearman correlation analysis was used to analyze the correlation between parameters. The differences of parameters among different groups were compared by one-way analysis of variance or Kruskal-Wallis test, and multiple or pairwise comparisons using LSD-t test or Mann-Whitney U test. Results: There was a negative correlation between axial length and corneal refractive power in 627 eyes (r=-0.62, P<0.001). Corneal refractive power was positively correlated with anterior chamber depth (r=0.26, P=0.006), while in the K≥45 D group, corneal refractive power was also positively correlated with anterior chamber depth (r=0.23, P=0.025). Anterior chamber depth [M (Q1,Q3)] was 1.77 (1.64, 1.90) mm in the K<42 D group, 1.85 (1.70, 2.14) mm in the 42 D≤K<45 D group and 2.02 (1.81, 2.18) mm in the K≥45 D group. Multiple comparisons showed that there were significant differences in anterior chamber depth between the K<42 D group and the K≥45 D group, between the 42 D≤K<45 D group and the K≥45 D group (U=14 372.00, 18 226.00; both P<0.05). There was a negative correlation between corneal refractive power and corneal diameter in 627 eyes (r=-0.52,P<0.001), while in the 42 D≤K<45 D group and the K≥45 D group, corneal refractive power were also negatively correlated with corneal diameter (r=-0.20, -0.28; both P<0.05). Corneal diameter was (11.77±0.43) mm in the K<42 D group, (11.24±0.35) mm in the 42 D≤K<45 D group and (10.90±0.33) mm in the K≥45 D group, while there were significant differences in multiple comparisons (t=1.92, 2.96, 2.01; all P<0.05). There was no correlation between corneal refractive power and anterior chamber volume, or between corneal refractive power and anterior chamber angle in 627 eyes (all P>0.05). There was no significant difference both in anterior chamber volume and in anterior chamber angle among 3 groups (all P>0.05). Conclusion: For age-related cataract patients with normal axial lengths and shallow anterior chambers, the anterior chamber depth increase and the corneal diameter decrease with the increase of corneal refractive power, but there is no significant change in anterior chamber volume and anterior chamber angle.

Changes in anterior segment parameters of normal subjects during accommodation using a Scheimpflug imaging system

Background: Accommodation changes ocular parameters, such as the anterior chamber volume (ACV), anterior chamber depth (ACD), anterior chamber angle (ACA), and pupil diameter (PD), which can reflect a risk of angle-closure glaucoma. Previous studies of changes in ocular anterior segment parameters, have used high diopters or maximum amplitude. Here, we focused on normal accommodation at a reading distance of 30‒40 cm. The aim of this study was to assess changes in anterior segment parameters during a normal accommodative state, using a Scheimpflug imaging system.&#x0D; Methods: In this cross-sectional study, 40 emmetrope subjects (mean ± SD of age: 22 ± 4.0 years) who met the inclusion criteria and provided informed consent were enrolled. Clinical history, refraction, amplitude of accommodation, slit lamp examination, Goldman applanation tonometry, and Pentacam investigations were performed on all subjects. Accommodative and non-accommodative targets were induced via the Pentacam. Two seconds were allowed for accommodation or relaxation prior to measurements in each eye.&#x0D; Results: Eighty normal eyes were evaluated; a small but statistically significant change in ACV, ACA, and PD during accommodation (P &lt; 0.01, &lt; 0.01, and &lt; 0.05, respectively) was observed. The ACD did not change substantially with accommodation (P = 0.29). The mean ± SD values of ACV, ACD, ACA, and PD before and after accommodation were 151.85 ± 24.04 mm3 and 145.38 ± 23.30 mm3, 2.87 ± 0.28 mm and 2.86 ± 0.27 mm, 35.06° ± 3.68° and 33.84° ± 3.72°, and 3.46 ± 0.57 mm and 3.41 ± 0.53 mm, respectively.&#x0D; Conclusions: Accommodation changes ocular parameters, such as ACV, ACA, and PD, in healthy young emmetropes. Interestingly, the ACD remains unaltered during accommodation. Nevertheless, although these changes were statistically significant, they were not clinically significant in our study.

Four-year observation of the changes in corneal endothelium cell density and correlated factors after Implantable Collamer Lens V4c implantation

BackgroundTo evaluate the changes in corneal endothelium cell density (ECD) and the correlated factors after Implantable Collamer Lens (ICL) V4c implantation.MethodsIn this retrospective, consecutive study, 48 eyes of 25 patients...

Weighted Comparison of the Corneal Topographic Data in Intracapsular versus Ciliary Sulcus Intraocular Lens Implantation during Phacoemulsification Surgery.

Objectives:This study aimed to evaluate the preoperative and postoperative changes in corneal topography, intraocular pressure (IOP), and visual acuity in patients who developed posterior capsule rupture during phacoemulsification surgery and simultaneously underwent ciliary sulcus intraocular lens (IOL) implantation and in those with intact capsular integrity who simultaneously underwent intracapsular IOL implantation and to compare these changes within and between the two groups.Methods:Among the 855 patients, 92 eyes of 69 patients whose corneal topography, IOP, and best-corrected visual acuity (BCVA) were successfully measured were included in the study. Preliminary chamber parameters [horizontal visible iris diameter (HVID), iridocorneal angle, anterior chamber volume (ACV), and anterior chamber depth (ACD)] were measured before and after surgery using a Sirius corneal topography device.Results:The IOL was implanted in the capsular bag in 58 patients and in the ciliary sulcus between the posterior iris and the capsule in 34 patients. In the sulcus IOL group, both BCVA and IOP measurements statistically significantly increased in the postoperative period compared with the preoperative values (p<0.001). As regards postoperative changes between the intracapsular and sulcus IOL groups, no significant difference was found in the changes in HVID (p=0.584), iridocorneal angle (p=0.282), and ACD (p=0.382), whereas the changes in ACV, IOP, and BCVA were statistically significantly different (p=0.020, p<0.001, and p<0.001, respectively).Conclusion:While the IOP of the sulcus IOL group significantly increased, that of the intracapsular group significantly decreased. Visual acuity increased in both lens implants, but patients with intracapsular lenses had greater improvement in visual acuity; thus, intracapsular IOL implantation was more advantageous than sulcus IOL implantation.

Comparison of eye-rubbing effect in keratoconic eyes and healthy eyes using Scheimpflug analysis and a dynamic bidirectional applanation device

To compare the effect of eye rubbing on Scheimpflug imaging parameters and corneal biomechanics in eyes with keratoconus and healthy eyes. Oftalmosalud Instituto de Ojos, Lima, Peru. Prospective cohort study. The study included healthy and keratoconus patients who attended the institution between January 2017 and July 2017. Eye rubbing was performed for 1minute followed by a 5-second break, followed by further rubbing for 1minute. Baseline tests were performed before rubbing; post-rubbing tests were performed immediately after (0minutes), and then again at 7minutes and 14minutes. Parameters related to anterior and posterior curvature and elevation, pachymetry, and corneal biomechanics obtained from tomography with a rotating Scheimpflug camera (Pentacam HR) and a dynamic bidirectional applanation device (Ocular Response Analyzer) were measured and compared between healthy and keratoconic eyes. The study included 30 healthy eyes and 31 keratoconic eyes. In the healthy group, the immediate mean changes in steeper anterior keratometry, posterior astigmatism, anterior chamber volume (ACV), flattest posterior keratometry, and Goldmann-correlated intraocular pressure (IOPg) after eye rubbing were 0.07 diopters (D)±0.15 (SD), -0.01±0.08 D, 0.03±7.06mm3, -0.001±0.04mm, and -1.21±1.99mm Hg, respectively, whereas the mean changes in the keratoconus group were -0.03±0.32 D, 0.14±0.50 D, -5.09±8.45mm3, 0.03±0.06mm, and -1.61±1.41mm Hg, respectively. There were statistically significant differences between the preoperative and postoperative eye-rubbing values of posterior astigmatism, ACV, and IOPg in the keratoconus group (P=.03, P=.0003, and P=.001, respectively) but not in the healthy group (P=.65, P=.85, and P=.23, respectively). Unlike the healthy eyes group, the keratoconus group experienced significant changes in ACV, IOP, and corneal posterior astigmatism after eye rubbing.

Observation of anterior chamber volume after cataract surgery with swept-source optical coherence tomography.

To investigate the changes in the anterior chamber volume (ACV) with swept-source optical coherence tomography (SS-OCT) after cataract surgery and the factors that influence these ACV changes. This was a prospective cohort study. Fifty-one patients who underwent cataract surgery were enrolled. Their ACV, anterior chamber depth, and angle widths were measured with SS-OCT before and 1day, 1week, and 1month after surgery. The associations between the changes in ACV and posterior vitreous detachment (PVD) and axial length (AXL) were determined. Compared with the preoperative volume, ACV increased significantly at all three time points after surgery (all p < 0.001). ACV was greater at 1week after surgery than at 1day after surgery (p < 0.001). Both AXL and the presence of PVD were significantly associated with the change in ACV at 1day after surgery (p = 0.005). However, neither PVD nor AXL affected the change in ACV between 1day and 1week after surgery. ACV stabilized in the first week after cataract surgery. The absorption of irrigation fluid and balanced salt solution in the vitreous cavity contributed to the change in ACV 1week after surgery. Eyes with longer AXL and PVD tended to show less change in ACV at 1day after surgery.

Measurement of and Factors Associated with the Anterior Chamber Volume in Healthy Chinese Adults.

Purpose. To measure the anterior chamber volume (ACV) and determine factors associated with the ACV in healthy Chinese adults. Methods. In this cross-sectional study, we used swept-source optical coherence tomography (SS-OCT) to measure ACV and other anterior segment parameters. Factors associated with ACV were also determined. Results. A total of 313 healthy Chinese adults were enrolled. The anterior segment parameters, including ACV, could be measured by SS-OCT with excellent repeatability and reproducibility. There was a significant difference between the horizontal and vertical anterior chamber widths (ACW) (P < 0.05), with a mean difference of 390 μm. The ACV (mean 153.83 ± 32.42 mm3) was correlated with most of the anterior segment parameters, especially anterior chamber depth (ACD), which accounted for about 85% of the variation of ACV. Most of the anterior segment parameters were significantly correlated with age, and the relative changes in ACV and ACD were greatest in subjects aged 41–50 years. Conclusion. ACV was correlated with most of the anterior segment parameters measured in this study, particularly ACD. The relatively large difference between horizontal and vertical ACW suggests that the ACV could and should be measured using multiple OCT scans.

No change in anterior chamber dimensions after femtosecond LASIK for hyperopia.

Objective:To compare the changes in anterior chamber volume (ACV), anterior chamber depth (ACD) and anterior chamber angle (ACA) before and 6 months after femtosecond laser in situ keratomileusis (LASIK) for hyperopia using the Pentacam HR device.Methods:A total of 24 eyes of 24 consecutive hyperopic patients undergoing femtosecond LASIK were examined preoperatively and 6 months postoperatively. Anterior chamber volume; ACDs in the central, superior, inferior, nasal, and temporal quadrants; and ACA were measured using the Pentacam HR device. Comparisons of preoperative versus postoperative values were performed using paired Student t test. Linear regression analysis was performed to evaluate correlations between ACV change, central ACD change, age, and attempted maximum ablation depth.Results:Preoperative and postoperative mean ACVs were 153.6 and 158.2 μL, respectively. Preoperative and postoperative mean ACDs were 2.81, 2.28, 2.53, 2.16, and 2.61 mm, and 2.84, 2.31, 2.54, 2.16, and 2.65 mm, respectively. Preoperative and postoperative mean ACAs were 33.3° and 32.0°, respectively. There were not statistically significant differences in ACV, ACDs, and ACA from preoperatively to 6 months after femtosecond LASIK (all P>0.05). The change of central ACD was correlated significantly with age at 6 months postoperatively (R2=0.18, P=0.039).Conclusions:Anterior chamber profiles, including ACV, ACA, and central and peripheral ACDs did not significantly change after femtosecond LASIK for hyperopia.

Long-term results of corneal collagen crosslinking for progressive keratoconus

PurposeTo evaluate long-term keratoconus stability after corneal crosslinking (CXL) with riboflavin. MethodsIn this prospective study, 57 eyes of 55 patients with progressive keratoconus, consecutively treated with ultraviolet A (UVA) – riboflavin CXL, were examined with the corneal topographer Pentacam, the biometer IOLMaster and the analyzer of corneal biomechanics Ocular Response Analyzer before and during a 24 months follow-up after CXL. ResultsTwenty-four months after CXL, there was a significant improvement in best corrected visual acuity (BCVA) (P<0.01), a significant decrease in corneal thinnest point (CTP), keratometry readings at the keratoconus apex (K max), and corneal volume (CV) (P<0.01), and a significant increase in axial eye length (AL) (P=0.01). No significant changes in anterior chamber volume (ACV) and depth (ACD), (P=0.8), corneal hysteresis (CH) (P=0.16) and corneal resistance factor (CRF) (P=0.06) were found. However, in the subgroup of patients with decreased K max readings 24 months after treatment, both CH and CRF showed a significant reduction (P<0.01). ConclusionIn the first month after the procedure, CXL induces a reduction in corneal volume. During the 24 months follow-up the cornea tends to recover its original volume with a persistence of the CXL efficacy.

Anterior Chamber Morphology Before and After Laser Peripheral Iridotomy Determined by Scheimpflug Technology in White Patients With Narrow Angles

To investigate the changes of anterior segment morphology in patients with narrow angles using a rotating Scheimpflug camera before and after laser peripheral iridotomy (LPI). Forty-six eyes of 46 patients classified as primary angle closure suspect, primary angle closure, primary angle closure glaucoma, acute angle closure glaucoma, fellow eyes of acute angle closure glaucoma, and iris plateau configuration were enrolled in this prospective interventional case series. Anterior chamber volume (ACV), anterior chamber depth (ACD), and anterior chamber angle (ACA) were evaluated with an Scheimpflug camera, before and after LPI. After LPI, the average anterior chamber depth increased from 1.88 ± 0.36 to 1.93 ± 0.32 mm (P=0.49). The mean ACV increased from 74.6 ± 25 to 89.4 ± 21.1 mm (P=0.003). The average ACA increased from 21.1 ± 4.8 to 23.4 ± 3.8 degrees (P=0.01). Eyes with synechial angle closure (primary angle closure and primary angle closure glaucoma) demonstrated a significantly smaller change in ACV compared with eyes with appositional angle closure (primary angle closure suspect). ACV and ACA determined by Scheimpflug technology increase to a statistically significant degree and this change appears to be more pronounced in cases of appositional angle closure.

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.

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.

Comparison of Preoperative and Postoperative Anterior Segment Measurements with Pentacam in Horizontal Muscle Surgery

To evaluate the effect of horizontal muscle surgery (recession or recession plus resection) on the anterior chamber parameters in patients after strabismus surgery. The Scheimpflug of 18 eyes of 12 patients with horizontal deviations were recorded just before surgery and 1 month after surgery. The power of anterior surface of cornea in horizontal and vertical axis, thinnest corneal thickness, anterior chamber depth, anterior chamber volume, and cornea volume were analyzed. The clinical characteristics of patients, the size of the deviations, the surgical doses, and observed responses to surgery were reviewed. There were six male and six female patients with an average age of 11.4 years (range, 4 to 22 years). Mean preoperative deviation was 47.91 PD (range, 20 to 75 PD), eight patients had esotropia with 57.5 PD average deviation (range, 40 to 75 PD), and four patients had exotropia with 28.75 PD average deviation (range, 20 to 35 PD). Of these 18 eyes, 12 eyes had horizontal muscle recession and 6 eyes had recession plus resection surgery. At the end of 1 month, three patients were orthophoric and eight patients had residual deviations varying between 16 and 35 PD. Preoperative and postoperative comparison of the whole study group documented insignificant changes in anterior chamber parameters and in keratometer readings. However, after dividing patients into two groups-recession or recession plus resection group-only one parameter, anterior chamber volume, was significantly reduced in recession plus resection group. Patients with strabismus who undergo recession plus resection procedure are prone to change in anterior chamber volume. Study with larger groups and long follow-up is necessary for clearer documentation of alterations at anterior chamber parameters.

A Study on Diurnal Fluctuation of Blood-Aqueous Barrier Permeability to Plasma Proteins

The diurnal change of blood-aqueous barrier permeability to protein molecules was investigated in 20 eyes of 10 normal volunteers. Simultaneous determinations of aqueous flow rate and the coefficient of entry into the anterior chamber (kin) for plasma protein were performed at different times of the day: (a) 0800 to 1100 hr: (b) 1900 to 2200 hr of the same day; (c) 0800 to 1100 hr of the next day; (d) 1400 to 1700 hr 1 week later; and (e) 0200 to 0500 hr of the following morning. Aqueous flow rate was determined by fluorophotometry and kin was calculated for each period from flow rate, plasma protein concentration, anterior chamber volume and aqueous protein concentration measured with a laser flarecell meter. Calculated values for kin did not fluctuate significantly among the periods, and there were no significant changes in anterior chamber volume or plasma protein concentration. Aqueous protein concentration and flow rate showed diurnal fluctuations, the patterns of which inversely corresponded to each other. It was concluded that permeability of the blood-aqueous barrier to protein remains fairly stable over a 24-hr period and the diurnal variation of aqueous protein concentration is mostly attributable to that of aqueous flow rate.