Pilot study supporting the existence of novel lymphatic channels within the canine anterior uveal tract using Lyve-1 and CD31.

OBJECTIVE: To demonstrate the existence of lymphatics in the canine anterior uvea using lymphatic-specific markers Lyve-1, Prox-1, and podoplanin, the endothelial cell marker CD31, and basement membrane matrix marker collagen IV. DESIGN: Prospective Study. ANIMALS: Eight normal globes from animals euthanized for unrelated health problems. PROCEDURES: Sagittally cut serial sections of six normal canine eyes were immunofluorescence double-stained with Lyve-1 and CD31 and single-stained with colorimetric Prox-1 and collagen IV. Three serial sections from 2 additional eyes were cut in the coronal plane at the level of the ciliary body and immunofluorescence double-stained with Lyve-1 and CD31 to map lymphatic channel distribution. Lymphatics from normal canine lymph nodes were used for validation of podoplanin. RESULTS: Four of 6 of the sagitally sectioned eyes had Lyve-1-positive lymphatic-like structures that were distinct from CD31-positive blood vessels in the iris base and ciliary body. Both of the coronally sectioned globes had Lyve-1-positive lymphatic-like structures in the ciliary body. The location of these structures was evaluated and found to be diffusely present circumferentially around the ciliary body. CONCLUSION AND CLINICAL RELEVANCE: These results support the existence of lymphatic channels in the anterior uveal tract of the canine eye. This could indicate the presence of a novel uveolymphatic outflow pathway, which may play a role in aqueous humor outflow. Future studies are needed to confirm the existence and elucidate the role of this proposed uveolymphatic outflow pathway and potentially develop novel treatment options for managing glaucoma.

Anatomy of the ciliary sulcus and the optimum site of needle passage for intraocular lens suture fixation in the living eye.

PURPOSE: To determine the relationship of the anatomic position of tissue surrounding the ciliary sulcus using ultrasound biomicroscopy (UBM) for measurement of ciliary sulcus parameters and the surrounding tissue after intracapsular cataract extraction (ICCE) and determine the correct suture site for intraocular lens (IOL) suture fixation. SETTING: Sugiura Eye Clinic, Asahi General Hospital, Shizouka-ken, Japan. DESIGN: Prospective case series. METHODS: Using UBM, the angle of the ciliary sulcus and several areas of the tissue surrounding the ciliary sulcus were measured from 8 orientations in eyes after ICCE. These measurements and endoscopic observation of the ciliary sulcus indicated the optimum points of needle insertion and needle emergence on the sclera for IOL suture fixation. Endoscopic observation of the ciliary sulcus also showed its shape. RESULTS: The shape of the surrounding tissue of the ciliary sulcus was measured in 16 eyes after ICCE, and endoscopy was used to observe the ciliary sulcus during surgery in 150 eyes. For ab interno ciliary sulcus suture fixation, the correct point of needle emergence on the sclera was 2.5 mm from the posterior surgical limbus when a straight needle was used. For ab externo pars plana suture fixation, the correct point of needle insertion on the sclera was 3.0 mm from the posterior surgical limbus. Endoscopic observation showed that the lower surface of the ciliary sulcus was formed by the fusion of neighboring ciliary processes. CONCLUSION: Knowing the detailed shape of ciliary sulcus will allow for more precise IOL suture fixation.

Tolerance of high and low amounts of PLGA microspheres loaded with mineralocorticoid receptor antagonist in retinal target site.

Mineralocorticoid receptor (MR) contributes to retinal/choroidal homeostasis. Excess MR activation has been shown to be involved in pathogenesis of central serous chorioretinopathy (CSCR). Systemic administration of MR antagonist (MRA) reduces subretinal fluid and choroidal vasodilation, and improves the visual acuity in CSCR patients. To achieve long term beneficial effects in the eye while avoiding systemic side-effects, we propose the use of biodegradable spironolactone-loaded poly-lactic-co-glycolic acid (PLGA) microspheres (MSs). In this work we have evaluated the ocular tolerance of MSs containing spironolactone in rat' eyes. As previous step, we have also studied the tolerance of the commercial solution of canrenoate salt, active metabolite of spironolactone. PLGA MSs allowed in vitro sustained release of spironolactone for 30days. Rat eyes injected with high intravitreous concentration of PLGA MSs (10mg/mL) unloaded and loaded with spironolactone maintained intact retinal lamination at 1month. However enhanced glial fibrillary acidic protein immunostaining and activated microglia/macrophages witness retinal stress were observed. ERG also showed impaired photoreceptor function. Intravitreous PLGA MSs concentration of 2mg/mL unloaded and loaded with spironolactone resulted well tolerated. We observed reduced microglial/macrophage activation in rat retina compared to high concentration of MSs with normal retinal function according to ERG. Spironolactone released from low concentration of MSs was active in the rat retina. Low concentration of spironolactone-loaded PLGA MSs could be a safe therapeutic choice for chorioretinal disorders in which illicit MR activation could be pathogenic.

Reproducibility and Agreement of Anterior Segment Parameter Measurements Obtained Using the CASIA2 and Spectralis OCT2 Optical Coherence Tomography Devices.

PURPOSE: To assess the reproducibility and agreement of measurement values obtained from the Tomey CASIA2 and Heidelberg Spectralis OCT2 anterior segment optical coherence tomographic devices. METHODS: Twenty eyes from 10 subjects ranging from age 28 to 45 years with no history of eye conditions or intraocular surgery were included. Two scans were obtained with each device in a standardized dark room environment after a period of dark adaptation. One anterior segment optical coherence tomography image along the horizontal (temporal nasal) meridian was analyzed per eye and per scan. Lens vault, pupil diameter, anterior chamber width, angle opening distance, trabecular iris space area, and scleral spur angle were measured using manufacturer-provided image analysis programs. Intraclass correlation coefficient (ICC) values, coefficients of variation, and Bland-Altman plots were computed to assess the intradevice correlation and interdevice agreement of measurement values. RESULTS: There was excellent intradevice reproducibility of measurement values for both the CASIA (ICC range, 0.86 to 0.99) and Spectralis (ICC range, 0.79 to 1.00). There was also excellent interdevice correlation of measurement values (ICC range, 0.78 to 0.93) for all parameters except anterior chamber width (ICC 0.20). Linear regression models and Bland-Altman plots showed that this relationship was strongest when measurement values were small. CONCLUSIONS: There is excellent intradevice reproducibility and good interdevice agreement of anterior segment parameter measurement values for the CASIA2 and Spectralis OCT2. However, the measurements obtained with each device should not be considered interchangeable.

[Clinical analysis of malignant glaucoma after glaucoma surgery].

OBJECTIVE: To explore the risk factors, the ciliary body anatomy structures, the therapeutic methods and the prognosis for malignant glaucoma through retrospectively collecting the clinical data from primary angle-closure glaucoma (PACG) patients. METHODS: Clinical data in 1183 patients (1456 eyes) with PACG were collected between July, 2010 and May, 2014 from Xiangya Hospital, Central South University. Thirty patients (38 eyes) were diagnosed as malignant glaucoma. According to symptom, these patients were divided into a PACG group (1418 eyes) and a malignant glaucoma group (38 eyes); according to age, they were divided into a 3-40 years old group (171 eyes), a 41-70 years old group (1016 eyes) and a ≥71 years old group (269 eyes); according to therapeutic methods, they were divided into a drug therapy group (5 eyes), a lens extraction group (6 eyes) and a vitrectomy surgery group (27 eyes); according to the different method of surgery, they were divided into a vitrectomy group (27 eyes), a nonvitrectomy group (11 eyes). The age, sex, anterior chamber depth (ACD), axial length (AL), lens thickness (LT), visual acuity, intraocular pressure, therapeutic methods and surgery history were recorded. Meanwhile, the ciliary body thickness (CBT), trabecular ciliary process angle (TCA) and lens diameter were measured by ultrsound biomicroscopy (UBM). RESULTS: Male and female ratio was 1:2 in the malignant glaucoma group. The average age [(51.87±12.92) years] in the malignant glaucoma group was less than that in the PACG group [(57.87±8.78) years](P<0.05). Malignant glaucoma was more likely to occur in the first 3 months after PACG trabeculectomy with a rate of 85.7%. The LT [(4.33±0.67) mm], AL[(21.44±1.18) mm] and ACD [(2.12±0.41) mm] in the malignant glaucoma group were less than those in the PACG group [(4.81±0.50), (22.17±0.97) and (2.49±0.48) mm, respectively](all P<0.05). The CBT0, CBT1, CBTmax, TCA and lens diameter in the malignant glaucoma group were less than those in the PACG group (all P<0.05). CONCLUSION: Female PACG patients, with short axial length, shallow anterior chamber, thin lens, thin ciliary body, small trabecular ciliary process angle and short lens diameter, are more likely to suffer from malignant glaucoma. Vitrectomy can significantly reduce intraocular pressure.

Bringing accommodation into focus: the several discoveries of the ciliary muscle.

Since at least the 16th century, many investigators have speculated on the presence of a specialized muscle in the front of the eye designed to somehow alter its disposition to bring about changes in focus. By the 1850s, when Hermann von Helmholtz offered the first plausible theory of accommodation, the anatomy of the ciliary muscle was well known. The credit for this knowledge is generally given to Ernst Brücke and William Bowman, who published their observations on the muscle independently in the 1840s. In fact, not only were Bowman and Brücke wrong about the role of the ciliary muscle in accommodation, and for different reasons, but they shared this distinction with at least 3 investigators who came before them. In the 3 decades before 1840, Philip Crampton, Robert Knox, and William Wallace had all zeroed in on the ciliary muscle, describing its anatomy in varying detail. If none understood its precise role in accommodation--all ignored the work of Thomas Young, who by 1800 had proved that the lens must somehow round up to achieve near vision--each deserves a share of the credit for its discovery.

[Analysis of anatomy features for patients with narrow anterior chamber angle and primary iridociliary body cysts].

OBJECTIVE: To investigate the prevalence and anatomy features of iridociliary body cysts in patients with narrow anterior chamber angle. METHODS: Retrospective case series study. The prevalence and anatomy features of iridociliary body cysts in 223 patients (402 eyes) were analyzed retrospectively with ultrasound biomicroscopy (UBM). All of the patients were examined for susceptive narrow anterior chamber angle without complaint. The age of the patients, the site, diameter and number of cysts, the anterior chamber angle and the central anterior chamber depth were measured. RESULTS: Iridociliary body cysts were found in 19 patients (23 eyes) out of 223 patients (402 eyes), the prevalence is 5.7%. Fifteen patients were unilateral and four patients bilateral. Two cases originated from the ciliary process, eighteen cases from the iris root, and three from both the root and posterior surface of the iris. Twenty one cases were single cysts while two cases were multiple cysts. The diameter of the cysts ranged from 0.5 to 3.1 mm, averaged (0.71 ± 0.53) mm. The average age and the central anterior chamber depth of the eyes with iridociliary body cysts were (55.32 ± 10.74) years and (2.25 ± 0.39) mm, with no significant difference (t = 0.534, 0.783; P > 0.05) as compared to that of patients without cysts, which were (57.46 ± 10.52) years and (2.14 ± 0.34) mm. The anterior chamber angle in iridociliary body cysts group was 8.2° (21.0°, 0.0°), with no significant difference (Z = -0.062, P > 0.05) as compared to that of patients without cysts, which was 8.9° (21.4°, 0.0°). CONCLUSIONS: The prevalence rate of iridociliary body cysts in this study is 5.7%, central anterior chamber depth and anterior chamber angle in patients with cysts do not differ form patients without cysts.

Repeatability of the ciliary sulcus-to-sulcus diameter measurement using wide-scanning-field ultrasound biomicroscopy.

PURPOSE: To evaluate the interexaminer and intraexaminer variance in ciliary sulcus-to-sulcus (STS) diameter measurements using wide-scanning-field ultrasound biomicroscopy (UBM) (Vumax II). SETTING: Nagoya Eye Clinic, Nagoya, Japan. DESIGN: Evaluation of diagnostic test or technology. METHOD: Two examiners measured the STS diameter 10 times in each subject. Intraexaminer and interexaminer variances were calculated. To determine interexaminer variance at each UBM measurement step, the examiner was changed every 2 steps when the STS diameter was measured. The Bland-Altman plot test was used to analyze each step of measurement variance. RESULTS: Thirty eyes of 15 volunteers (9 men, 6 women; mean age 29.6 years ± 6.2 [SD]) were enrolled. The mean coefficient of variation was 0.62% ± 0.20% for intraexaminer measurements and 3.4% ± 2.4% for interexaminer measurements. There were statistically significant differences between the 2 examiners in the step of extracting images and determining and measuring the STS diameter (P=.02). The 95% confidence intervals in all steps were relatively high (recordings, -1.02 to 1.08 mm; extracting images and determining and measuring STS; -0.79 to 1.25 mm). CONCLUSION: Interexaminer variance in STS measurement should be considered if the STS diameter is used for selecting the size of posterior chamber phakic intraocular lenses.

Comparative analysis of white-to-white and angle-to-angle distance measurements with partial coherence interferometry and optical coherence tomography.

PURPOSE: To perform white-to-white (WTW) and angle-to-angle (ATA) distance measurements with 2 optical devices and analyze the correlation with other anterior segment parameters. SETTING: Department of Ophthalmology, Medical Health and Science Center, University of Debrecen, Debrecen, Hungary. DESIGN: Comparative case series. METHODS: In this prospective study, the WTW distance, axial length (AL), and anterior chamber depth (ACD) were measured by partial coherence interferometry (PCI) (IOLMaster). The horizontal and vertical ATA distances and ACD were assessed by anterior segment optical coherence tomography (AS-OCT) (Visante). RESULTS: The mean PCI values were AL, 23.31 mm ± 1.52 (SD); WTW distance, 11.99 ± 0.47 mm; ACD, 2.99 ± 0.4 mm. On AS-OCT, the mean horizontal ATA was 11.43 ± 0.51 mm and the mean vertical ATA, 10.72 ± 0.66 mm. The WTW distance was significantly greater than the horizontal ATA distance, and the horizontal ATA distance was significantly greater than the vertical ATA distance (P<.0001). The correlations between WTW and horizontal ATA (r = 0.51; P<.0001), vertical ATA (r = 0.32; P<.0021), AL (r = 0.45; P<.0001), and patient age (r = -0.28; P = .023) were significant. The PCI WTW distance and ACD were significantly correlated (r = 0.55; P<.0001). There were no significant correlations between AS-OCT horizontal and vertical ATA measurements (r = -0.02; P = 0.79) or between same-device ACD measurements (r = 0.18; P = .15). CONCLUSIONS: Although PCI WTW and AS-OCT ATA measurements are not clinically interchangeable, the WTW values correlated well with horizontal and vertical measurements and other anterior segment parameters.

Ciliary sulcus diameter and two anterior chamber parameters measured by optical coherence tomography and VHF ultrasound.

PURPOSE: To evaluate the relationship between two anterior chamber anatomical parameters, angle-to-angle and iris pigment end-to-iris pigment end distances, and sulcus-to-sulcus diameter. METHODS: Twenty eyes without active ocular pathologies or previous ocular surgeries from 20 patients ranging in age from 23 to 51 years were included in this study. Mean spherical equivalent refraction ranged from +5.50 to -7.00 diopters. Angle-to-angle and iris pigment end-to-iris pigment end distances were measured in all cases three times consecutively using two technologies: optical coherence tomography (OCT) and very high-frequency ultrasonography. Sulcus-to-sulcus diameter was additionally obtained by ultrasonography. Correlation, linear regression, intrasession, and interchangeability analysis between parameters was performed. RESULTS: Mean sulcus-to-sulcus diameter was 11.92+/-0.80 mm. Mean angle-to-angle distance was 12.14+/-0.52 mm for ultrasonography and 12.23+/-0.59 mm for OCT. Mean iris pigment end-to-iris pigment end distance was 12.18+/-0.51 mm for ultrasonography and 12.29+/-0.61 mm for OCT. No statistically significant differences were found among these anatomical parameters (unpaired Student t test, all P>.10). Statistically significant correlations were found between sulcus-to-sulcus diameter and angle-to-angle distance and between sulcus-to-sulcus diameter and iris pigment end-to-iris pigment end distance for both imaging techniques. For ultrasonography, range of agreement was 0.90 mm between sulcus-to-sulcus diameter and angle-to-angle distance and 0.74 mm between sulcus-to-sulcus diameter and iris pigment end-to-iris pigment end distance. These ranges increased to 1.22 mm and 1.14 mm, respectively, for OCT measurements. CONCLUSIONS: Angle-to-angle and iris pigment end-to-iris pigment end distances are correlated with sulcus-to-sulcus diameter, but they cannot be used as equivalent parameters.

Anterior chamber angle measurement with optical coherence tomography: intraobserver and interobserver variability.

PURPOSE: To assess intraobserver and interobserver variability of anterior segment optical coherence tomography (AS-OCT) as an objective diagnostic tool to quantify the anterior chamber angle and opening width. SETTING: University Eye Clinic, Lübeck, Germany. METHODS: The anterior chamber angle and opening width were assessed in 18 eyes of 9 healthy volunteers by 2 observers. Intraobserver reproducibility was evaluated by calculating an intraclass correlation coefficient (ICC) in a mixed model. Each observer had a separate model using information from 5 scans. Interobserver variability was determined by Bland-Altman analysis. The ICC was calculated in a mixed model using a residual maximum likelihood method. The results of 3 and 5 repeated scans were evaluated to indicate the change to 1 measurement application. RESULTS: The mean anterior chamber angle measurement was 35.9 degrees +/- 5.7 (SD) for observer A and 36.2 +/- 5.7 degrees for observer B. The ICC was 0.94 and 0.91, respectively. The mean opening width was 315 +/- 62 microm for observer A and 317 +/- 60 microm for observer B. The ICC was 0.97 and 0.93, respectively. Interobserver comparisons showed a mean difference between anterior chamber angle measurements of -0.27 +/- 1.6 degrees, a limit of agreement (LOA) interval from -3.52 to 2.98 degrees, and an ICC estimate of 0.96. The mean difference in opening width measurements was 2.40 +/- 12.40 microm, the LOA from -27.20 to 22.40 microm, and the estimated ICC 0.96. Using 1 instead of the mean of 5 measurements, the LOA range increased by 3.46 degrees for the anterior chamber angle and 30.0 microm for the opening width. CONCLUSION: Anterior chamber angle and opening width measurements by OCT showed low intraobserver and interobserver variability, indicating OCT is a valuable technique for quantitative assessment that provides reproducible measurements and objective documentation by different examiners.

Macromorphometric study on ciliary body location in canine eyes.

This macroscopic study firstly examined the precise locational information of the canine ciliary body, i.e., the ciliary crown and the ciliary ring in the beagle. The safe and effective transscleral laser photocoagulation technique requires the accurate location of the ciliary body. In both sides of the eyeball in 10 beagle dogs, the width of the ciliary ring and the distance from the limbus to the ciliary ring were measured with calipers using a stereomicroscope at the 8 points. The widest portion of ciliary body was found at the dorsal to ventro-temporal area of the lateral canthus (lateral portion of the eyelid; ear side). In contrast, the narrowest portion was seen at the ventro-nasal to nasal area of the medial canthus (medial portion of the eyelid; nasal quadrants). Use of transscleral photocoagulation at the present narrowest area of ciliary body may carry a high risk of destruction of the optic portion of retina.

Relation between injected volume and optical parameters in refilled isolated porcine lenses.

PURPOSE: This study was performed to elucidate the correlation between added lens refill material and enhanced lens power as well as the correlation between lens refilling volume and accommodative amplitude as determined by equatorial stretching of ex vivo refilled pigs' lenses. METHODS: Nine porcine lenses were refilled with increasing amounts of silicone oil. After each refill step, the lens power, the lens power change, and the lens thickness were measured both in the relaxed state and with a 3-mm larger ciliary body diameter. In addition, the spherical aberration of the refilled lenses was also quantified. RESULTS: Injection of 0.04 mL silicone material into the relaxed lens enhanced the lens power by 1 D. A 0.54-mm increase of the lens thickness in relaxed lenses added 1 D to the lens power. Increasing the lens refilling volume decreased the lens power changes measured at 3-mm ciliary body stretch. Spherical aberration was positive in the refilled lenses and increased with increasing lens refilling volume. CONCLUSION: The correlation found between the refilling volume and the lens power (0.04 mL D(-1)), as well as the correlation between the lens thickness and the lens power (0.54 mm D(-1)), might be important factors to be controlled in conjunction with surgery, as these also determine the lens power in the presence of this refill material. An increasing lens filling volume is associated with decreasing accommodative amplitude. The positive spherical aberration of refilled porcine lenses presents a sharp contrast to the negative aberration of natural pigs' lenses. Different lens contours and the transition from a gradient to a homogeneous refractive index might be responsible for this change in spherical aberration.

Correlation between different measurements within the eye relative to phakic intraocular lens implantation.

PURPOSE: To obtain measurements of the white-to-white distance and the anterior chamber and ciliary sulcus diameters in phakic human eyes obtained post-mortem to find a correlation between these measurements. SETTING: David J. Apple, MD Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Twenty-two phakic human eyes obtained from eye banks within 24 hours of death were evaluated. The following measurements were performed: white-to-white distance, anterior chamber diameter with a plastic sizer after a small limbal incision, and anterior chamber and ciliary sulcus diameters after fixation and sagittal section of the eyes. The first 10 eyes were studied at the 6 o'clock to 12 o'clock meridian and the last 12 eyes, at the 3 o'clock to 9 o'clock meridian. RESULTS: A positive correlation was found between the white-to-white measurements and the anterior chamber diameter in the 10 eyes studied at the 6 o'clock to 12 o'clock meridian but not in the 12 eyes studied at the 3 o'clock to 9 o'clock meridian. The latter is the meridian frequently used by surgeons to perform white-to-white measurements and thus choose the overall size of the phakic intraocular lens to be implanted. No correlation was found between the white-to-white measurements and the ciliary sulcus diameter in the 2 meridians. CONCLUSION: Experimental studies using cadaver eyes are helpful in evaluating sizing techniques for phakic IOL implantation as well as in better understanding the anatomical relationships between ocular structures.

Predicting sulcus size using ocular measurements.

PURPOSE: To predict sulcus size using ocular measurements. SETTING: Michel Pop Clinics, Montreal, Quebec, Canada. METHODS: Forty-three eyes were evaluated using several techniques. Ultrasound biomicroscopy (UBM) echograms were taken to measure the anterior chamber depth (ACD), sulcus size, and central corneal thickness. The limbus size was measured with a caliper. Axial length, ACD, and pachymetry were measured by contact ultrasonography. Refraction and corneal power were also evaluated. RESULTS: The coefficient of linear regression was 0.05 between the limbus and the sulcus size (P =.78), 0.76 between ultrasonography and UBM ACD measurements (P <.001), and 0.69 between ultrasonography and UBM pachymetry (P <.001). Paired t tests showed that ultrasound and UBM ACD measurements were not statistically different (P =.70) but that ultrasound and UBM pachymetry measurements were (P <.001). The sulcus versus limbus difference was 0.6 mm for myopia and 0.3 mm for hyperopia. A backward elimination multiple regression performed with all measures to predict sulcus size resulted in the following formula: Sulcus size = 18.9 - 0.023 x sphere + 0.15 x mean keratometry (R = 0.49; P =.005; statistical power = 0.89; standard error of estimate = 0.5 mm). CONCLUSION: Traditional estimation of sulcus size through limbal measurement is inadequate because limbus size alone cannot predict sulcus size. A general formula using the sphere and the mean corneal power can help predict sulcus size. Corneal power was significantly and negatively correlated with sulcus and limbus size as well as sphere. The standard error of sulcus measurement by UBM was 0.4 mm.

Real-time optical coherence tomography of the anterior segment at 1310 nm.

BACKGROUND: Recent advances in high-speed scanning technology have enabled a new generation of optical coherence tomographic (OCT) systems to perform imaging at video rate. Here, a handheld OCT probe capable of imaging the anterior segment of the eye at high frame rates is demonstrated for the first time. OBJECTIVE: To demonstrate real-time OCT imaging of anterior segment structures. DESIGN: Survey of anterior segment structures in normal human subjects. SETTING: Laboratory. MAIN OUTCOME MEASURES: Achieving real-time imaging of the anterior segment, satisfactory image quality, and convenience of a handheld probe. RESULTS: Optical coherence tomographic imaging of the anterior segment of the eyes of human subjects was performed using 1310-nm wavelength light with an image rate of 8 frames per second. Imaging trials demonstrated clear resolution of corneal epithelium and stroma, sclerocorneal junction, sclera, iris pigment epithelium and stroma, and anterior lens capsule. The anterior chamber angle was clearly visualized. Limited imaging of the ciliary body was performed. Real-time imaging of pupillary constriction in response to light stimulus was also performed. CONCLUSION: High-speed OCT at 1310-nm wavelength is a potentially useful technique for noninvasive assessment of anterior segment structures. CLINICAL RELEVANCE: Our results suggest that real-time OCT has potential applications in glaucoma evaluation and refractive surgery.

First experimental and clinical results with transscleral optical coherence tomography.

BACKGROUND AND OBJECTIVE: To evaluate the potentials of optical coherence tomagraphy (OCT) using long wavelength to penetrate highly scattering tissues of the eye and visualize the anterior chamber angle and the ciliary body. METHODS: OCT images were generated by an experimental prototype in enucleated porcine eyes using as light source a superluminiscent diode with a wavelength of 1310 nm and a scan frequency of 60 Hz. The number of lateral scans was variable in a range from 100 to 400. RESULTS: Infrared OCT was able to penetrate the sclera. The anterior chamber angle could be visualized completely and the ciliary body could be identified. However, it was not possible to penetrate the highly reflective iris pigment epithelium. CONCLUSION: The use of infrared OCT allows penetration of the sclera, thus, providing complete visualization of the anterior chamber angle and limited demonstration of the ciliary body. Because of its higher resolution, it may represent an interesting noninvasive alternative to ultrasound biomicroscopy.

Comparison of ciliary sulcus fixation techniques for posterior chamber intraocular lenses.

OBJECTIVE: To anatomically and histologically evaluate suturing techniques for sulcus fixation of posterior chamber intraocular lenses. SETTING: Kitano Hospital, Osaka, Japan. METHODS: The reproducibility of three suturing techniques (perpendicular to the eye wall; parallel to the iris; midway between perpendicular to the eye wall and parallel to the iris) were evaluated in a postmortem eye. Histologic sections of another eye and ultrasound biomicroscopy (UBM) images of 21 normal eyes were evaluated to determine the safety zone for the needle to avoid damaging adjacent structures. RESULTS: The ciliary sulcus was completely penetrated in the three techniques in 100, 40, and 70% of cases, respectively. The histologic sections and the UBM images showed that when sutures were placed perpendicular to the eye wall, there was the possibility of postoperative angle closure and suturing parallel to the iris might damage adjacent structures because of a narrow safety zone. CONCLUSIONS: The needle should penetrate obliquely, as in the technique in which the suturing is midway between perpendicular to the eye wall and parallel to the iris. This technique provides better reproducibility and causes less damage to adjacent tissue.

Ultrasound biomicroscopy. High-frequency ultrasound imaging of the eye at microscopic resolution.

UBM presents us with a new method of imaging the anterior segment of the eye at high resolution. Its strengths lie in its ability to produce cross-sections of the living eye at microscopic resolution without violating the integrity of the globe. UBM, although lacking the resolution of optical microscopy, gives us images in living eyes without affecting the internal relationships of the structures imaged. There are many other applications of this new imaging method. Examples of other uses include imaging adnexal pathology, assessing corneal changes with refractive surgery, the assessment of trauma, and determination of intraocular lens position.