Temporal Anterior Chamber Angle Research Articles

Changes in corneal high order aberrations and anterior chamber parameters following scleral fixated intraocular lens implantation

BackgroundTo evaluate the change in corneal high order aberrations (HOAs) and anterior chamber parameters following scleral fixation in aphakic patients using the Scheimpflug camera system. MethodsThis retrospective study included patients who were aphakic after phacoemulsification surgery and underwent scleral-fixed intraocular lens (SF-IOL) implantation with Z suture technique between 2010 and 2022. Preoperative and postoperative best corrected visual acuity (BCVA), anterior segment parameters and corneal aberrations were evaluated with a combined Scheimpflug-Placido disk corneal topography device (Sirius Costruzione Strumenti Oftalmici, Florence, Italy). The following values were recorded: Simulated keratometry (SimK), flat meridian (K1), steep meridian (K2), iridocorneal angle (ICA), temporal anterior chamber angle (T-ACA), nasal anterior chamber angle (N-ACA), horizontal anterior chamber diameter (HACD), anterior chamber volume (ACV), corneal volume (CV), total Root Mean Square (RMS), high order aberrations (HOAs), spherical aberration, coma, trefoil, quadrifoil, and secondary astigmatism. ResultsThe study included 31 eyes of 31 patients (mean age: 63.00 ± 19.41 years, 17 males/14 females). Postoperative BCVA was better than preoperative BCVA (p = 0.012). Postoperatively, there was a statistically significant increase in ACV and CV values and a statistically significant decrease in K2 (p = 0.009, p = 0.032, p = 0.015). Preoperative T-ACA and preoperative and postoperative ACV were negatively correlated with postoperative intraocular pressure (r=-0.427 p = 0.033, r=-0.406 p = 0.032 and r=-0.561 p = 0.001). There were statistically significant postoperative increases in corneal RMS, trefoil and HOAs for 3 mm pupil diameter (p = 0.0177, p = 0.001, p = 0.031) and in corneal RMS, trefoil and quadrifoil aberrations for 6 mm pupil diameter (p = 0.033, p = 0.001, p = 0.001). ConclusionsIn conclusion, SF-IOL implantation with Z-suture technique used for visual rehabilitation of aphakic patients may affect visual quality by increasing corneal HOAs while improving visual acuity.

Early outcomes of anterior segment parameters after implantable collamer lens V4c implantation

BackgroundThis study investigated the early outcomes of anterior segment parameters after implanting an implantable collamer lens with a central hole (ICL V4c) in patients with myopia and determined the earliest follow-up time for detecting potential complications.MethodsSixty-two patients were included, and the following parameters were measured at baseline (preoperative), 1 day, 1 week, and 1, 3, and 6 months after the operation: intraocular pressure (IOP), endothelial cell density (ECD), central anterior chamber depth (CACD), anterior chamber volume (ACV), nasal and temporal anterior chamber angle (n-ACA and t-ACA), horizontal corneal diameter (white-to-white, WTW), and axial length (AL). The vault was measured at each post-operative timepoint.ResultsThe postoperative IOP and ECD at the 6 months were both statistically similar to the baseline. The post-operative CACD and ACV were significantly less at all timepoints compared with the baseline (P < 0.001) and stayed stable from 1 day and 1 month after the operation, respectively. Postoperative n-ACA and t-ACA decreased significantly at 1 day and 1 week compared with the baseline (P < 0.001), while tended to stabilization at 1, 3, and 6 months. The vault kept decreasing significantly at 1 day, 1 week, and 1 month, but stayed stable at 3 and 6 months. The postoperative n-ACA and t-ACA positively correlated with the baseline ACA, CACD, and ACV.ConclusionsThe anterior chamber parameters tended to stabilization early after the operation. Thus, it is essential to evaluate patients’ anterior segment status at earlier timepoints and prevent complications with prompt and non-invasive intervention.

Anterior segment optical coherence tomography findings in the Infant Aphakia Treatment Study (IATS): a secondary analysis of a randomized clinical trial

To correlate the diagnosis of glaucoma among children in the Infant Aphakia Treatment Study (IATS) by age 10 years with anterior segment optical coherence tomography (AS-OCT) findings. A multicenter randomized controlled trial of 114 infants with unilateral congenital cataract who were 1-6 months of age at surgery. Data on long-term glaucoma-related status and outcomes were collected when children were 10.5 years old. Participants were randomized at cataract surgery to either primary intraocular lens (IOL) or no IOL implantation (contact lens [CL]). AS-OCT findings in eyes with glaucoma were compared to eyes which did not have glaucoma and to the fellow eyes, between fellow and treated eyes, and between the IOL and CL groups. There were no significant differences in the mean nasal and temporal anterior chamber angle (ACA) or mean nasal and temporal angle opening distance (AOD) for nonglaucomatous, glaucomatous, and fellow eyes (P = 0.31, 0.16, 0.43, 0.08 resp.). There were also no significant differences in mean nasal and temporal ACA and AOD between fellow and treated eyes (P = 0.44, 0.67, 0.57, 0.38 resp.), or between IOL and CL groups (P=0.36, 0.35, 0.49, 0.44, resp.). AS-OCT confirmed that eyes with glaucoma in IATS had predominantly open angles with similar ACA and AOD to eyes without glaucoma and to fellow eyes. Furthermore, congenital cataract surgery with or without an IOL did not result in a significant difference in ACA or AOD compared to fellow eyes in IATS.

Anterior segment parameters on optical coherence tomography in healthy South Asian children

PurposeHigh resolution spectral domain optical coherence tomography (SD-OCT) was used to assess the anterior segment structure parameters in healthy South Asian children. Methods108 eyes of 54 healthy children ≤ 16 years were recruited after a thorough eye exam. The anterior segment analysis was be done by Optopol Revo 80 high resolution SD-OCT. Central corneal thickness (CCT), Angle opening distance (AOD), Anterior chamber (AC) angle, Trabecular iris space area (TISA), Trabecular iris angle (TIA), iris thickness at 2 mm, internal AC diameter and lens vault were evaluated. ResultsMean age was 11.38 years. Mean IOP was 13.63 mmHg, mean axial length, 22.82 mm, mean spherical equivalent, -0.14 D, mean CCT, 532.6 µm and mean CDR was 0.31. The mean internal AC diameter was 11609.15 µm. The nasal and temporal AC angles was 53.54° and 50.37°, respectively [P = .033]. The nasal and temporal AOD500 were 0.9 mm and 0.85 mm, respectively [P = .629]. The nasal and temporal AOD750 were 1.21 mm and 1.06 mm, respectively [P = .583]. The nasal TIA was 41.75°; the temporal TIA; 40.24° [P = .325]. The nasal TISA500 was 0.33 mm2; the temporal TISA500, 0.31 mm2 [P = .012]. The nasal TISA750 was 0. 59 mm2; the temporal TISA750, 0.56 mm2 [P = .746]. The nasal iris thickness at 2 mm was 483.54 µm; the temporal iris thickness, 505.8 µm [P = .273]. The mean lens vault was -519.58 µm. ConclusionsOur study data depicts the normal anterior segment parameters in healthy Pakistani children.

Changes in anterior chamber dimensions following small incision lenticule extraction (SMILE).

To evaluate the changes in anterior chamber dimensions including horizontal anterior chamber diameter (HACD), anterior chamber depth (ACD), and iridocorneal angle (ICA) following small incision lenticule extraction (SMILE) using Scheimpflug-Placido disk tomographer (Sirius). The records of the 73 eyes of 47 patients who received SMILE for myopia and myopic astigmatism were retrospectively reviewed. Preoperative and 6-month postoperative measurements of central corneal thickness (CCT), HACD, ACD, ICA, nasal anterior chamber angle (nACA), and temporal anterior chamber angle (tACA) were obtained by tomography, and compared with paired t-tests. Pearson's correlation and linear regression tests were used to evaluate the relationship between these parameters. The CCT, HACD, and ACD values decreased significantly at 6-month postoperatively (p < 0.05 for all). ICA, nACA, and tACA showed no statistically significant difference postoperatively (p = 0.54, p = 0.118, and p = 0.255, respectively). Pearson's correlation analysis confirms negative relationship between Δ-HACD and Δ-tACA (r = -0.475, p < 0.01), and a loose negative relationship between change in ACD and change in ICA (r = -0.282, p = 0.016). Age and Δ-tACA were found as predictive parameters for Δ-HACD and, Δ-ICA was a predictor for Δ-ACD. While HACD and ACD decreased significantly, there was no significant change in ICA, nACA and tACA. Changes in HACD and ACD should be considered in terms of subsequent surgeries after SMILE.

Distribution of anterior chamber angle measurements in South African young adults: an optical coherence tomography study

Assessment of anterior chamber angle (ACA) variables is important to screen, diagnose and monitor ocular anomalies. Even though data on ACA variables, such as angle-opening distance taken at 500µm (AOD500) and trabecular-iris angle (TIA), are available in the literature, limited information is available about these variables in African sub-populations. The purpose of this study is to describe the distribution of ACA measurements (AOD500 and TIA) in a South African young adult population. In this cross-sectional study, 700 young adults were recruited from a university student population using two-stage random sampling. The Optovue iVue 100 optical coherence tomographer was used to measure the ACA variables. The distribution of the AOD500 and TIA measurements was analysed using descriptive and inferential statistics. Data from only the right eyes were analysed because the ACA measurements in the two eyes showed high levels of interocular symmetry. The measurements for the nasal and temporal ACAs were asymmetrically distributed (p < 0.001). The median AOD500 measurements in the nasal and temporal angles were 539µm and 542µm, respectively. The median TIA measurements were similar (~ 36°) in the two horizontal angles. The temporal ACA measurements were slightly higher than the nasal ACA measurements. Females had higher median ACA measurements than males (p ≥ 0.029). The ACA measurements in South African young adults resemble non-Gaussian curves. The ACA measurements are different from that reported in other sub-populations worldwide and most participants had ACA measurements associated with non-occludable ACAs.

Anterior chamber angle features in primary congenital glaucoma infants using hand-held anterior segment-oct.

To describe anterior chamber angle (ACA) structures and parameters in primary congenital glaucoma (PCG) and normal infant eyes, using Hand-held anterior segment optical coherence tomography (HH AS-OCT), as an in-office, non-contact technique. Normal and PCG-infants <24 months were examined, using HH AS-OCT (RTVue RT- 100, Optovue Inc., Fremont, CA). Sedation was not required. Corneal pachymetry map, ACA width and iris thickness (IT) were measured. Trabecular meshwork (TM), Schlemm's canal (SC), and scleral spur (SS) identification were assessed in both groups. Forty-eight infants; (26 PCG-eyes and 22 normal-eyes) aged 9.12 ± 6.7 months, were included. Nasal and temporal ACA width in PCG infants was found significantly larger (39.3 ± 6.6° vs. 30.4 ± 5.6, and 40.1 ± 5.3° vs. 32.5 ± 6.2 respectively) (p < 0.001). IT was significantly reduced (121.7 ± 43.9 μm in PCG-infants, vs. 160.3 ± 38.6 μm in normal-eyes) (p < 0.01). TM was identified in all normal eyes (100%) and nine (34.6%) PCG- eyes. SC was identified in 16 (72.7%) normal eyes versus four (15.4%) PCG. In PCG-eyes, an abnormal structure occluding the angle was seen in seven (26.9%), and a hyper-reflective membrane in five (19.2%), the iris was anteriorly inserted in all PCG-eyes, and iridotrabeculodysgenesis was clearly identified (with constant iris anterior insertion). The abnormal tissue obscuring the angle was seen in younger PCG-infants and iris thinning appeared to be part of the pathology, not a result of IOP elevation. Using HH AS-OCT permits tomographic examination of the ACA in PCG infants and may help in the understanding of disease pathology. Hence, may assist in optimizing treatment.

The alteration of anterior chamber angle after implantable collamer lens implantation in phakic eye

Objective To observe the alteration of anterior chamber angle after implantable collamer lens (ICL) implantation in phakic eye. Methods The data of 41 eyes of 22 cases with high myopia who received ICL V4c implantation from Dec. 2017 to Sep. 2018 were collected and analyzed retrospectively.Visante anterior segment OCT examination were performed in all cases before and 1, 3 months after surgery. The nasal and temporal anterior chamber angle (ACA), angle opening distance at 500 μm and 750 μm(AOD500, AOD750), trabecular-iris space area at 500 μm and 750 μm(TISA500, TISA750) were observed before and after surgery. Results The difference in parameters of anterior chamber angle (ACA, AOD500, AOD750, TISA500 and TISA750) were not statistically significant between temporal and nasal angle (P>0.05). Postoperative anterior chamber angle parameters (ACA, AOD500, AOD750, TISA500, TISA750) were significantly reduced compared with those before surgery, and the difference was statistically significant (P 0.05). Conclusion After ICL implantation, anterior chamber angle of phakic eye is narrowed obviously, but it is stable during 3 months follow-up. Key words: Lens, artificial, posterior chamber, phakic eye; Myopia, high; Anterior chamber angle; Anterior angle opening distance; Trabecular-iris space area

Lentiviral Vector-Mediated Expression of Exoenzyme C3 Transferase Lowers Intraocular Pressure in Monkeys.

Primary open-angle glaucoma (POAG) is considered a lifelong disease characterized by optic nerve deterioration and visual field damage. Although the disease progression can usually be controlled by lowering the intraocular pressure (IOP), therapeutic effects of current approaches do not last long. Gene therapy could be a promising method for persistent treatment of the disease. Our previous study demonstrated that gene transfer of exoenzyme C3 transferase (C3) to the trabecular meshwork (TM) to inhibit Rho GTPase (Rho), the upstream signal molecule of Rho-associated kinase (ROCK), resulted in lowered IOP in normal rodent eyes. In the present study, we show that the lentiviral vector (LV)-mediated C3 expression inactivates RhoA in human TM cells by ADP ribosylation, resulting indisruption of the actin cytoskeleton and altered cell morphology. In addition, intracameral delivery of the C3 vector to monkey eyes leads to persistently lowered IOP without obvious signs of inflammation. This is the first report of using a vector to transduce the TM of an alive non-human primate with a gene that alters cellular machinery and physiology. Our results in non-human primates support that LV-mediated C3 expression in the TM may have therapeutic potential forglaucoma, the leading cause of irreversible blindness in humans.

DYNAMIC CHANGES OF THE ANTERIOR CHAMBER ANGLE PRODUCED BY INTRAVITREAL ANTI-VASCULAR GROWTH FACTOR INJECTIONS.

To use anterior segment optical coherence tomography (AS-OCT) to evaluate the anterior chamber after intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections. Preinjection and immediate postinjection AS-OCT images were taken and measurements were compared including angle opening distance (AOD) and trabeculo-iris space area (TISA) at 500 μm and 750 μm from the scleral spur (AOD500, AOD750, TISA500 and TISA750, respectively), and the scleral spur angle. Twenty-one eyes from 21 patients were studied. There was significant narrowing of the temporal AOD500, AOD750, and temporal angle after injection (P = 0.03, 0.01, and 0.02, respectively). The percentage of narrowing of the nasal TISA500 and TISA750 was significantly greater in phakic versus pseudophakic eyes (P = 0.03 and 0.02, respectively). A higher postinjection IOP was correlated with increased narrowing of the nasal AOD500, TISA500, TISA750, and nasal angle (R = 0.22, 0.28, 0.34 and 0.20; P = 0.03, 0.01, 0.005 and 0.04, respectively) and a smaller preinjection anterior chamber depth in phakic eyes (R = 0.53, P = 0.01). After an anti-vascular endothelial growth factor injection, there is significant narrowing of the temporal anterior chamber angle in all eyes and increased narrowing of the nasal angle in phakic compared with pseudophakic eyes. Physicians performing intravitreal injections should be aware of these associations as they may contribute to our understanding of prolonged elevation of IOP after injections.

Evaluation of anterior chamber angle under dark and light conditions in angle closure glaucoma: An anterior segment OCT study

To evaluate changes of nasal and temporal anterior chamber angle (ACA) in subjects with angle closure glaucoma using Spectralis AS-OCT (SAS-OCT) under dark and light conditions. Based on dark-room gonioscopy, 24 subjects with open angles and 86 with narrow angles participated in this study. The nasal and temporal angle opening distance at 500 μm anterior to the scleral spur (AOD500), nasal and temporal ACA were measured using SAS-OCT in light and dark conditions. In 2 groups, ACA and AOD500 in nasal and temporal quadrants were significantly greater in light compared to dark (all with p=0.000). The AOD500 and ACA were significantly higher in nasal than temporal in measured conditions for 2 groups except the ACA and AOD500 of normal group measured in light. The difference between nasal and temporal in dark (29.07 ± 65.71 μm for AOD500 and 5.7 ± 4.07° for ACA) was greater than light (24.86 ± 79.85 μm for AOD500 and 2.09 ± 7.21° for ACA) condition. But the difference was only significant for ACA (p=0.000). The correlation analysis showed a negative correlation between AOD500 and pupil diameter in temporal and nasal quadrants (both with p=0.000). While temporal AOD500 difference correlated with spherical equivalent, temporal and asal gonioscopy, nasal AOD correlated with IOP, temporal and nasal gonioscopy. Clinically important changes in ACA structure could be detected with SAS-OCT in nasal and temporal quadrants under different illumination intensity. The results could help in improvement of examination condition for better and more accurate assessment of individuals with angle closure glaucoma.

Sources of variability of the van Herick technique for anterior angle estimation

BackgroundThe purpose of the present study was to investigate two potential sources of variability of the traditional van Herick technique for temporal anterior chamber angle estimation, namely the need to compare the depth of the peripheral anterior chamber (PACD) with the thickness of the peripheral cornea (PCT), and the possible loss of information resulting from restricting the assessment of the anterior chamber angle (ACA) to the temporal limbus.MethodsBoth image analysis and Scheimpflug photography were employed to measure PCT and PACD in a group of 82 eyes (mean ± SD age of 32.8 ± 4.1 years) with and without narrow anterior chamber angles. Subjective and semi‐objective van Herick grades were compared and the relationship between PCT and PACD was investigated. Scheimpflug photography was also used to determine the value of the narrowest anterior chamber angle and to compare it with the temporal angle.ResultsNo statistically significant differences were encountered between semi‐objective and subjective grades. A weak statistically significant correlation was found between image analysis values for PCT and PACD (r = 0.295; p = 0.007). Upon examining Scheimpflug photographic data, no statistically significant association between PCT and PACD was revealed. Temporal and minimum anterior chamber angles presented statistically significant differences (t = 7.213; p < 0.001). In approximately 65 per cent of the patients, the minimum ACA was not located at the temporal limbus, with a difference of up to 9.8 degrees between minimum and temporal angles.ConclusionThe encountered association between the image analyses of PCT and PACD advocates for the direct measurement of PACD as a better estimation of ACA depth than the ratio between PCT and PACD. All anterior chamber quadrants should be examined, as the minimum ACA may not be located temporally.

Anterior segment optical coherence tomography in acute anterior uveitis.

To analyze the corneal thickness and anterior chamber (AC) angle using anterior segment optical coherence tomography (AS-OCT) in patients with acute anterior uveitis (AAU). Twenty two patients (24 eyes) were included. All patients underwent complete ophthalmological examination, applanation tonometry and AS-OCT at diagnosis and fifteen days after treatment. Average corneal thickness before treatment was 564.2 ± 44.2 µm, 580.0 ± 44.3 µm and 580.1 ± 2.9 µm, respectively in central, pericentral and paracentral cornea. Fifteen days after treatment a significant decrease of corneal thickness was observed, with 529.5 ± 33.1 µm (p=0.0091) and 542.6 ± 33.6 µm (p=0.0068), respectively in central and pericentral cornea; paracentral corneal thickness (557.8 ± 35.3 µm) thinning did not reach statistical significance (p=0.1253). There was no significant change in temporal AC angle between visits, 44.3 ± 14.4 degrees before treatment and 44.7 ± 14.7 degrees fifteen days after (p=0.9343), and mean intraocular pressure, 10.8 ± 4.5 mmHg before treatment and 12.3 ± 3.0 mmHg fifteen days after (p=0.1874). In the studied group, AS-OCT detected a decrease of corneal thickness after AAU treatment. Temporal AC angle and intraocular pressure did not change during the studied period.

Anterior Chamber Angle Measurements Using Schwalbe’s Line With High-resolution Fourier-Domain Optical Coherence Tomography

To use Fourier-domain optical coherence tomography (OCT) to measure the angle opening distance at Schwalbe's line (AOD-SL) and determine its value in anterior chamber angle assessment. Horizontal scans of the nasal and temporal anterior chamber angles in glaucoma subjects were performed at 830 nm wavelength Fourier-domain OCT. Images were graded by 2 ophthalmologists who assessed the visibility of Schwalbe's line (SL), anterior limbus (AL), scleral spur (SS), and angle recess (AR). AOD-SL was measured with computer calipers. SL was manually identified by the termination of the corneal endothelium. Gonioscopy was used to classify anterior chamber angles according to a modified Shaffer system. Spearman ρ analysis was performed to assess correlation between AOD-SL and modified Shaffer grade. A cutoff value of AOD-SL for diagnosing occludable angles (modified Shaffer grade ≤ 1) was determined by receiver operating characteristic (ROC) analyses. Thirty-five glaucoma subjects (65 eyes) were enrolled. SL, AL, AR, and SS were visible by OCT in 97.7%, 99.2%, 87.3%, and 80.8% of eyes, respectively. Nasal and temporal AOD-SLs were 322.6 ± 200.2 µm and 341.4 ± 197.4 µm, respectively. Correlation coefficients between AOD-SL and modified Shaffer grade were 0.80 (nasal) and 0.81 (temporal). The diagnostic cutoff value of AOD-SL for occludable angles was 290 µm. The areas under the ROC curve, sensitivity, specificity values were 0.90, 0.80, 0.87 (nasal) and 0.90, 0.85, 0.77 (temporal), respectively. The measurement of AOD-SL by Fourier-domain OCT is highly correlated with gonioscopy and may be a useful noncontact method for assessing angle closure risk.

Evaluation of Nasal and Temporal Anterior Chamber Angle with Four Different Techniques

Background: Anterior chamber angle (ACA) can be measured by many different techniques. In order for a technique to be a part of the routine eye examination, it has to be quick and easy in good agreement with gonioscopy both nasally and temporally. Aim: To investigate variation in ACA measurement between gonioscopy, van Herick technique, anterior segment optical coherence tomography (AS-OCT) and Sirius Scheimpflug-Camera both nasally and temporally. Method: The ACA of 50 eyes of 25 healthy subjects was measured with gonioscopy, van Herick technique, AS-OCT and Sirius Scheimpflug-Camera. The angle was measured both nasally and temporally. Results: No statistically significant difference could be found between gonioscopy, van Herick technique and AS-OCT either nasally or temporally. The Sirius Scheimpflug-Camera on the other hand showed statistically significant difference to gonioscopy (p Conclusion: This study showed good agreement between three of the four techniques. ACA measurements obtained by the Sirius Scheimpflug-Camera should therefore not be considered interchangeable with those obtained by the remaining three methods.

Anterior segment morphometry and intraocular pressure change after uneventful phacoemulsification

To evaluate the changes in anterior segment morphometry and intraocular pressure (IOP) with 3D rotating Scheimpflug camera-topography system after uneventful phacoemulsification. Materials and methods: In 56 eyes of 54 patients, anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), and central corneal thickness (CCT) were measured with the Sirius 3D Rotating Scheimpflug camera-topography system preoperatively and 1 month after surgery. IOP was measured with applanation tonometer. The preoperative and postoperative results were compared. Results: Preoperative and postoperative anterior segment parameters were as follows: ACD 2.7 ± 0.4 and 3.5 ± 0.3 mm, ACV 143.6 ± 48.8 and 192.4 ± 59.5 mm3, nasal ACA 42.3 ± 8.4° and 53.0 ± 4.5°, temporal ACA 36.9 ± 11.9° and 45.8 ± 13.2° (P < 0.001). CCT, iris diameter, and pupil diameter changes were not statistically significant (P > 0.05). Mean axial length (AL) was 23.4 ± 0.8 mm. The IOP and corrected IOP were 14.6 ± 3.5 and 14.5 ± 3.9 preoperatively and 10.4 ± 2.4 and 10.0 ± 3.3 mmHg postoperatively (P < 0.001). There was not a correlation between AL and IOP, ACD, ACV, or ACA, and no correlation was found between IOP change and ACD, ACV, or ACA (P > 0.05). Conclusion: Measurements confirm that after uneventful phacoemulsification, IOP decreases while ACD, ACV, and ACA increase. Preoperative AL and IOP changes did not correlate with ACD, ACV, and ACA.

Successful argon laser photocoagulation of diffuse epithelial ingrowth following concomitant persistent pupillary membrane removal and phacoemulsification

A 57-year-old woman had concomitant surgery of persistent pupillary membrane removal and uneventful phacoemulsification through the same temporal clear corneal incision in her left eye. Short axial lengths (right eye, 21.08 mm; left eye, 20.39 mm) with shallow angles were noted bilaterally, and other findings were not remarkable. The patient experienced angle-closure attacks 3 and 7 months postoperatively. At the second angle-closure attack, diffuse epithelial ingrowth was observed. The epithelial ingrowth covered the intraocular lens surface in the interpupillary area, the iris surface surrounding the pupil, and the temporal anterior chamber angle, but did not reach the corneal endothelial incision. After observation of iris blanching with laser photocoagulation, argon laser photocoagulation was applied to the epithelium covering the iris and angle 7 times during the following month. The epithelial ingrowth was completely removed and did not recur during the 36-month follow-up. No author has a financial or proprietary interest in any material or method mentioned.

Narrow- and Open-Angle Measurements with Anterior-Segment Optical Coherence Tomography and Pentacam™

To assess the agreement of the Pentacam (Oculus, Wetzlar, Germany) and anterior-segment optical coherence tomography (AS-OCT) in measuring open and narrow angles. Prospective observational case series in which 39 healthy normal subjects (39 eyes) and 25 patients with narrow angles (37 eyes) were enrolled between May and September 2008. The anterior chamber measurements were performed by AS-OCT and the Pentacam. There was no significant difference in the open-angle measurements between the Pentacam and AS-OCT (P > .05). However, in patients with narrow angles, the average values of nasal and temporal anterior chamber angles taken by the Pentacam were larger than those of AS-OCT (25.5° ± 5.66° and 25.77° ± 5.15° vs 13.40° ± 6.81° and 12.13° ± 6.47°; P < .001). Both AS-OCT and the Pentacam can reliably measure anterior chamber angles in healthy normal subjects. The difference in measuring narrow angles by the two instruments was due to inability to view the angle recess or the scleral spur with the Pentacam.

Assessment of Anterior Chamber Angle Using Visante OCT, Slit-Lamp OCT, and Pentacam

To assess and compare the anterior chamber angle (ACA) by different anterior segment imaging techniques. Forty healthy eyes of 40 normal subjects were recruited and 3 consecutive measurements of ACA were determined prospectively utilizing Visante optical coherence tomography (OCT), slit-lamp OCT (SL-OCT), and Pentacam. Statistical significance of interdevice differences between measurements was evaluated by Wilcoxon signed rank test and Bland-Altman analysis. The repeatability of 3 consecutive measurements was analyzed by repeated measured analysis of variance. Mean nasal and temporal ACA were detected as 31.2+/-8.7 and 32.1+/-8.5 degrees by Visante OCT; 41.6+/-5.9 and 41.8+/-5.2 degrees by Pentacam; and 42.9+/-10.0 and 43.3+/-10.1 degrees by SL-OCT. All devices displayed a high intrasession repeatability (Scheffe multiple comparison, p>0.05). ACA detected by Visante OCT were found significantly different from ACA calculated by Pentacam and SL-OCT (p<0.05). On the other hand, ACA data obtained by Pentacam and SL-OCT were found to be statistically similar (p>0.05). Although noncontact ACA measurements using all modalities were easy to handle and demonstrated good repeatability in healthy participants, the tested devices were not regarded as comparable. Hence, the clinician should take the different modalities into consideration during ACA assessment using various devices.

Vergleich verschiedener optischer Verfahren zur Vermessung der Dimensionen des okulären Vorderabschnitts

The evaluation of the anterior ocular chamber sections along the optical axis/axis of vision has been carried out using single-line partial coherence interferometry for many years. Now, new technologies such as the Scheimpflug-technique of the Pentacam (Oculus Optikgeräte GmbH, Wetzlar) and the optical coherence tomography of the Visante OCT (Carl Zeiss Meditec AG, Jena) allow the two-dimensional imaging of the anterior ocular segment in addition to goniometry and ultrasonic biomicroscopy. The internal anterior chamber depth, central corneal thickness, angle-to-angle distance, and nasal and temporal anterior chamber angles of eight eyes (four patients) were examined using the Visante OCT and the Pentacam at three measurement periods within three days as part of a reproducibility study. In a comparative clinical trial on 97 eyes (53 patients), three to five measurements were made of the same parameters used in the reproducibility study, as well as external anterior chamber depths and white-to-white distances. The imaging techniques show high reproducibility with coefficients of variation up to 5.05%. The biometry instruments returned significantly different measuring results for the internal anterior chamber depth, corneal thickness and anterior chamber angle. Compared to the IOLMaster, the Visante OCT and the Pentacam produced external anterior chamber depths which were larger by 0.10 mm on average. Compared to the ACMaster, the measured internal anterior chamber depths were 0.01 mm and 0.03 mm smaller. The mean central corneal thickness measured with the Visante OCT was 3 +/- 5 microm smaller than the measured values obtained using the ACMaster. Compared to both these devices, the Pentacam produced central corneal thickness that was more than 20 microm larger. Both the Visante OCT and the Pentacam determined angle-to-angle-distances that were up to 1.3 mm smaller and up to 1.6 mm bigger than white-to-white-distances with the IOLMaster and ACMaster. On average, the anterior chamber angle measured with the Pentacam was larger 5.5 +/- 5.8 degrees (nasal) and 6.5 +/- 6.7 degrees (temporal) than the results provided by the Visante OCT. The Pentacam and Visante OCT imaging biometry instruments enabled high reproducibility and highly precise measurements of intraocular distances and displays of the anterior ocular segment.