Displacement between anterior chamber width obtained by swept-source anterior segment optical coherence tomography and white-to-white distance.

PURPOSE: To determine the relationship between the external limbal location, represented by white-to-white (WTW) distance, and the actual angle location, represented by spur-to-spur (STS) and angle-to-angle (ATA) distances. METHODS: 166 eyes from 166 participants were imaged using CASIA2 anterior chamber optical coherence tomography (AS-OCT) and LenStar LS 900 optical biometer. The horizontal ATA and STS were measured using the swept-source Fourier-domain AS-OCT (CASIA2). The horizontal WTW was automatically measured using LenStar. The displacement lengths (DL) between WTW-STS and WTW-ATA were calculated. Bland-Altman plots and intraclass correlation were performed. RESULTS: The study showed that WTW has a positive correlation with STS (ICC = 0.82, p<0.001) and ATA (ICC = 0.82, p<0.001). The Bland-Altman analysis demonstrated that the mean difference of WTW-STS is 0.10 mm (95% CI 0.06 to 0.14 mm) with limits of agreement of -0.42 to 0.63 mm between WTW and STS, and the mean difference of WTW-ATA is 0.10 mm (95% CI 0.06 to 0.15 mm) with limits of agreement of -0.48 to 0.64 mm between WTW and ATA. Linear regression with adjustment showed that a WTW value greater than 12.07 mm is associated with a greater DL (WTW-STS DL ß 0.18, p = 0.003; WTW-ATA DL ß 0.14, p = 0.03). CONCLUSIONS: Greater WTW was significantly associated with higher displacement of WTW from the two distances representing anterior chamber width. External limbal location may not accurately represent the actual angle location in eyes with larger WTW.

Transplantation of Islets of Langerhans into the Anterior Chamber of the Eye for Longitudinal In Vivo Imaging.

Noninvasive in vivo imaging techniques are attractive tools to longitudinally study various aspects of islet of Langerhans physiology and pathophysiology. Unfortunately, most imaging modalities currently applicable for clinical use do not allow the comprehensive investigation of islet cell biology due to limitations in resolution and/or sensitivity, while high-resolution imaging technologies like laser scanning microscopy (LSM) lack the penetration depth to assess islets of Langerhans within the pancreas. Significant progress in this area was made by the combination of LSM with the anterior chamber of the mouse eye platform, utilizing the cornea as a natural body window to study cell physiology of transplanted islets of Langerhans. We here describe the transplantation and longitudinal in vivo imaging of islets of Langerhans in the anterior chamber of the mouse eye as a versatile tool to study different features of islet physiology in health and disease.

Scanning Electron Microscopy Evaluation of an EX-PRESS Mini Glaucoma Shunt After Explantation.

We report a case of an explanted stainless steel miniature glaucoma drainage device (EX-PRESS) implanted under a scleral flap for pseudoexfoliation open-angle glaucoma surgical treatment. The glaucoma shunt was implanted in a 75-year-old white man with medically refractive glaucoma. Cataract surgery was performed simultaneously. After 2 years, the shunt extruded through the scleral flap and the conjunctiva and it was, therefore, explanted. Scanning electron microscopy images of the EX-PRESS mini glaucoma shunt were acquired to verify the patency of the device lumen and the presence of fibrosis or cellular adhesion on the device. Energy dispersive spectroscopy for chemical surface characterization of the EX-PRESS shunt was performed. Scanning electron microscopy-acquired images showed minimal extracellular material proliferation on the lumen device. The energy dispersive spectroscopy analysis revealed a high peak of carbon suggesting the organic nature of the residuals found on the shunt lumen. The surface showed few superficial pits, likely due to an initial corrosion process.

Optic surface changes in Intraocular lens scaffold: An ex vivo study.

PURPOSE: We aimed to assess the micro injuries on the intraocular lens (IOL) optic in the IOL scaffold technique by ex vivo study. SETTING: This study was conducted at the Tahira Research Laboratory, Dr Agarwal's Eye Hospital and Eye Research Centre, Chennai. DESIGN: This was an experimental study. METHODS: IOL scaffold technique was simulated in 12 caprine eyes with moderate lens changes using 12 IOLs (six acrylic hydrophilic and six polymethyl methacrylate IOL) in experimental set up. IOLs (6 mm optic diameter) were explanted from the caprine eyes immediately after the surgery and examined under light microscopy and phase contrast microscopy for anterior and posterior optic changes, and again after 24 hours. Scanning electron microscopy (SEM) was performed in IOLs with abnormalities. Two IOLs placed in caprine eyes that did not undergo scaffold procedure acted as controls. A trocar anterior chamber maintainer was used in four eyes. RESULTS: Four out of 12 IOLs showed mark defects on the surface in mid periphery. Linear mark defects measured IOL 1 (190 µm), IOL 6 (18 µm), IOL 2 (2.33 µm, 2.3 µm, 14 µm, 14 µm) and IOL 5 (12 µm). The marks do not change after 24 hours. There were no mark defects (micro abrasions or scratches) seen on any of the IOL's in the central 4 mm of the optic anterior surface. The control IOLs showed no surface changes. The pre-experiment mark defects (n = 0) in study IOLs changed to post-experiment (n = 7), with no statistical significance obtained (p = 0.059). CONCLUSION: IOL scaffold technique can cause microscopic optic surface changes seen as linear marks defects in the mid periphery and intraoperative fluid maintenance can reduce its incidence.

A novel method for measuring anterior segment area of the eye on ultrasound biomicroscopic images using photoshop.

PURPOSE: To describe a novel method for quantitative measurement of area parameters in ocular anterior segment ultrasound biomicroscopy (UBM) images using Photoshop software and to assess its intraobserver and interobserver reproducibility. METHODS: Twenty healthy volunteers with wide angles and twenty patients with narrow or closed angles were consecutively recruited. UBM images were obtained and analyzed using Photoshop software by two physicians with different-level training on two occasions. Borders of anterior segment structures including cornea, iris, lens, and zonules in the UBM image were semi-automatically defined by the Magnetic Lasso Tool in the Photoshop software according to the pixel contrast and modified by the observers. Anterior chamber area (ACA), posterior chamber area (PCA), iris cross-section area (ICA) and angle recess area (ARA) were drawn and measured. The intraobserver and interobserver reproducibilities of the anterior segment area parameters and scleral spur location were assessed by limits of agreement, coefficient of variation (CV), and intraclass correlation coefficient (ICC). RESULTS: All of the parameters were successfully measured by Photoshop. The intraobserver and interobserver reproducibilities of ACA, PCA, and ICA were good, with no more than 5% CV and more than 0.95 ICC, while the CVs of ARA were within 20%. The intraobserver and interobserver reproducibilities for defining the spur location were more than 0.97 ICCs. Although the operating times for both observers were less than 3 minutes per image, there was significant difference in the measuring time between two observers with different levels of training (p<0.001). CONCLUSION: Measurements of ocular anterior segment areas on UBM images by Photoshop showed good intraobserver and interobserver reproducibilties. The methodology was easy to adopt and effective in measuring.

Utilidad de la gonioscopía diagnóstica en el glaucoma / Usefulness of gonioscopy for diagnosing glaucoma

Se realizó una revisión bibliográfica con el objetivo de exponer las principales características gonioscópicas presentes en los pacientes glaucomatosos; efectuando una búsqueda de los principales artículos científicos de los últimos años, así como de la literatura impresa que incluye el tema, siendo seleccionados los contenidos más relevantes para la confección del informe final. Se obtuvo que la gonioscopía, como método diagnóstico, le permite al oftalmólogo el reconocimiento de signos relacionados a las diferentes enfermedades glaucomatosas, por lo que constituye un método necesario y válido en el diagnóstico y clasificación de un glaucoma. Se hace imprescindible para todo profesional de esta rama de la medicina, dominar la técnica e interpretar sus hallazgos(AU)

A bibliographical review was made aiming at exposing the fundamental gonioscopical characteristics present in glaucoma patients; searching the main scientific articles in recent years, and also within the printed literature including the topic, being chosen the most relevant contents for the elaboration of the final report. It was concluded that gonioscopy, as a diagnostic means, allows the ophthalmologist to recognize signs related with the several glaucomatous diseases, a reason why it constitutes a necessary and valid method for diagnosing and classifying glaucoma. It is indispensable for any professional worker in this area of medicine to dominate the technique and interpret its findings(AU)

Morphology of the eyeball from the Humpback whale (Megaptera novaeangliae).

Aquatic mammals underwent morphological and physiological adaptations due to the transition from terrestrial to aquatic environment. One of the morphological changes regards their vision since cetaceans' eyes are able to withstand mechanical, chemical, osmotic, and optical water conditions. Due to insufficient information about these animals, especially regarding their sense organs, this study aimed to describe the morphology of the Humpback whale (Megaptera novaeangliae) eyeball. Three newborn females, stranded dead on the coast of Sergipe and Bahia, Brazil, were used. Samples were fixed in a 10% formalin solution, dissected, photographed, collected, and evaluated through light and electron microscopy techniques. The Humpback whale sclera was thick and had an irregular surface with mechanoreceptors in its lamina propria. Lens was dense, transparent, and ellipsoidal, consisting of three layers, and the vascularized choroid contains melanocytes, mechanoreceptors, and a fibrous tapetum lucidum. The Humpback whale eyeball is similar to other cetaceans and suggests an adaptation to diving and migration, contributing to the perception of differences in temperature, pressure, and lighting.

Dysfunctional uveoscleral pathway in a rat model of congenital glaucoma.

UNLABELLED: The purpose of the study was to investigate the presence of the uveoscleral pathway in the normotensive rat (NR) and in a rat model of congenital glaucoma (CGR). We injected the fluorescent tracer 70-kDa dextran rhodamine B in the anterior chamber of four NRs and four CGRs. At 10 and 60 minutes after injection, rats were euthanized by CO2 inhalation and eyes were enucleated. Cryosections were prepared and analyzed using fluorescent microscopy. Hematoxylin-eosin staining and electron microscopy of the anterior chamber angle (ACA) were performed. At 10 minutes after injection, fluorescent tracer was detected in the iris root and ciliary processes of NRs and CGRs. At 60 minutes, NRs showed prominent signal in the suprachoroidal, whereas, in the CGRs, tracer was barely detectable. Histology of the anterior chamber revealed the presence of an open ACA and electron microscopy confirmed the normal structure of the ciliary body in CGRs. CONCLUSIONS: Our results document the presence of an uveoscleral pathway in the normotensive rat. The rat model of congenital glaucoma shows severe impairment of the uveoscleral pathway, suggesting that alterations of the uveoscleral outflow might play a role in the pathogenesis of CG.

[Comparison between Lenstar LS 900 non-contact biometry and OcuScan RXP contact biometry for task delegation]. / Comparaison de la biométrie sans contact cornéen par LENSTAR LS 900 et de la biométrie contact par OCUSCAN RXP dans le cadre de la délégation de tâches.

INTRODUCTION: Non-contact biometers have many advantages including the delegation of tasks to orthoptists. This study analyses the reliability of measurements comparing contact and non-contacts techniques. PATIENTS AND METHODS: Comparative measurements were taken on 86 eyes of 45 patients (mean age: 74 years; 44.4 % males) in preoperative phacoemulsification by three orthoptists with experience in this task. Each patient had non-contact measurements (Lenstar LS 900, Haag-Streit) and contact measurements (corneal biometry and ultrasound pachymetry with OcuScan RXP, Alcon) and a keratometry refractometer (TONOREF II, Nidek). The axial length data, pachymetry, power of the intraocular lens (SRK/T formula), anterior chamber depth, and the average keratometry were analyzed by paired comparisons. RESULTS: The non-contact biometer was ineffective in 5.8 % of cases (Parkinson's disease, two cases; dense posterior subcapsular cataracts, three cases). The non-contact pachymetry was statistically significantly higher (546.4 µm vs. 538.6 µm; p<0.001). The axial length was significantly longer for the non-contact measurement (23.21 mm vs. 23.05 mm; p<0.0001). In 25.9 % of patients, this difference was greater than or equal to 0.3mm and affected the power of the implant chosen. The anterior chamber depth measured on non-contact biometry was statistically greater (3.33 mm vs. 3.03 mm; p<0.0001). However, there was no significant difference regarding the average keratometry (43.82 D vs. 43.78 D; p=0327). CONCLUSION: Besides the infectious benefit for patients, absence of cleaning and decontamination of biometric probes, non-contact measurements using Lenstar are an example of a safe activity that can be delegated to assistants. This technique has been used to optimize the refractive outcome of 25.9 % of our patients undergoing refractive cataract surgery.

Morphofunctional interactions of peripheral nerve fibers of the iris with neurons developing in the anterior chamber of the eye in rats.

Electron microscopic studies were performed on intraocular transplants of embryonic septal and hippocampal tissue developing in the anterior chamber of the eye in rats for 3-4 months. The aim of the study was to seek ultrastructural identification of peripheral nerve fibers entering transplants from the iris, and to assess their ability to establish true synaptic contacts with transplanted CNS neurons. Bundles of myelinated and unmyelinated axons surrounded by Schwann cell cytoplasm were seen within the perivascular spaces of ingrowing blood vessels. Both types of peripheral fiber were also identified in the neuropil areas of transplants. At the ultrastructural level, unmyelinated axons were found to be free of glial Schwann cell sheaths and to form typical asymmetrical synapses with the dendrites and dendritic spines of transplant neurons. These results provide evidence of the high morphofunctional plasticity of both parts (central, peripheral) of the nervous system.

[Morpho-functional interactions of the iris peripheral nervous fibers with the neurons developing in the rat anterior eye chamber].

The intraocular grafts of the septal or hippocampal embryonic tissues developing in the rat anterior eye chamber for three to four months were investigated by electron microscopy. The aim of this study was both the ultrastructural identification of the peripheral nervous fibers entering the grafts from host iris and the estimation of their capacity to establish true synaptic contacts with the central nervous system neurons of the grafts. The bundles of myelinated and unmyelinated axons, surrounded by the Schwann cell cytoplasm, were observed within the perivascular spaces of the ingrowing blood vessels. In the neuropil areas of the grafts, both types of the peripheral nervous fibers were also identified. It was demonstrated on the ultrastructural level that the unmyelinated axons lost their glial envelope of the Schwann cell and formed the typical asymmetric synapses with the dendrites and dendritic spines of the grafted neurons. The results are indicative of the high morpho-functional plasticity of both parts of the nervous system.

Sphingosine-1-phosphate effects on the inner wall of Schlemm's canal and outflow facility in perfused human eyes.

Previous work has shown that sphingosine 1-phosphate (S1P) decreases outflow facility in perfused porcine eyes while dramatically increasing giant vacuole density in the inner wall of the aqueous plexus, with no obvious changes in the trabecular meshwork (TM). Due to known effects of S1P on cell-cell junction assembly in vascular endothelia, we hypothesized that S1P would decrease outflow facility in human eyes by increasing the complexity of cell-cell junctions in Schlemm's canal (SC) inner wall endothelia. Perfusion of enucleated post mortem human eyes at 8 mmHg constant pressure in the presence or absence of 5 microM S1P showed that S1P decreased outflow facility by 36 +/- 20% (n = 10 pairs; p = 0.0004); an effect likely mediated by activation of S1P(1) and/or S1P(3) receptor subtypes, which were found to be the principal S1P receptors expressed by both TM and SC cells by RT-PCR, confocal immunofluorescence microscopy and western blot analyses. Examination of SC's inner wall using confocal microscopy revealed no consistent differences in VE-cadherin, beta-catenin, phosphotyrosine or filamentous actin abundance/distribution between S1P-treated eyes and controls. Moreover, morphological inspection of conventional outflow tissues by light and scanning electron microscopy showed no significant differences between S1P-treated and control eyes, particularly in giant vacuole density. Thus, unlike the situation in porcine eyes, we did not observe changes in inner wall morphology in human eyes treated with S1P, despite a significant and immediate decrease in outflow facility in both species. Regardless, S1P receptor antagonists represent novel therapeutic prospects for ocular hypertension in humans.

Ab interno trabeculectomy: ultrastructural evidence and early tissue response in a human eye.

PURPOSE: To report the results of ultrastructural analysis of the postoperative effects of ab interno trabeculectomy in a human eye. SETTING: Department of Ophthalmology, Palmanova Hospital, Palmanova, Udine, Italy. METHODS: A 60-year-old woman with cataract and glaucoma had enucleation for a choroidal melanoma 10 days after ab interno trabeculectomy combined with phacoemulsification. A second ab interno trabeculectomy was performed after enucleation to evaluate the outcomes of the previous trabeculectomy. Light and transmission electron microscopy analyses were performed on samples excised from areas (1) not subjected to a procedure (control samples), (2) that had ab interno trabeculectomy before enucleation, and (3) that had ab interno trabeculectomy immediately after enucleation. RESULTS: Control samples showed normal trabecular features. Semithin sections of all ab interno trabeculectomy samples showed full-thickness removal of trabeculum segments, with Schlemm's canal lumen opening into the anterior chamber and apparent preservation of the adjacent structures. On ultrathin sections of samples that had ab interno trabeculectomy before enucleation, the endothelium lining the outer wall of Schlemm's canal and other angle components showed intact ultrastructural features. In trabecular beams that were not removed, the extracellular matrix appeared to have maintained its fine texture and was free of activated fibroblasts or leucocyte infiltrates. CONCLUSIONS: Observations confirm that ab interno trabeculectomy causes direct communication between Schlemm's canal lumen and the anterior chamber in vivo and immediately after enucleation during the early postoperative period. The absence of an evident inflammatory reaction in the examined case should be considered with caution because of possible tumor-induced immune suppression.

Ultrastructural and biochemical evaluation of the porcine anterior chamber perfusion model.

PURPOSE: To evaluate a porcine anterior chamber perfusion model and to test the transferability of data obtained with this model to the human system. METHODS: Porcine eyes were obtained from a local abattoir and processed within 2 hours after death. Anterior chambers of 42 pairs of eyes were dissected with removal of lens, vitreous, iris, and ciliary processes and perfused for 72 (40 pairs) or 140 (2 pairs) hours with medium or medium supplemented with 10 ng/mL transforming growth factor (TGF)-beta2. Facility was continuously measured. Afterward, trabecular meshwork (TM) specimens from all quadrants were prepared, and sections were analyzed morphologically and with immunohistochemical methods. TM sections of 10 nonperfused pairs of eyes were used as the control. RNA and protein was extracted from the TM specimens. Expression of alphaB-crystallin, fibronectin (FN), plasminogen activator inhibitor (PAI)-1, thrombospondin (TSP)-1, and connective tissue growth factor (CTGF) mRNA and protein in medium-perfused and TGF-beta2-perfused anterior segments was examined by Northern and Western blot analyses. RESULTS: The nonperfused TM showed prominent differences between the temporal and nasal quadrants. Temporally, the ciliary muscle (CM) was pronounced, the scleral sulcus was long and flat, and the scleral spur extended toward the iris root. Nasally, the CM was thin, the sulcus deep, and the spur compact. The outer TM was expanded between the scleral spur and cornea throughout the entire circumference. On the ultrastructural level, the elastic network was connected to the cribriform TM cells and the aqueous plexus endothelium. Perfusion itself had only small effects on the morphology of the outer TM. Aqueous plexus loops remained open, and TM cells showed no signs of necrosis or pyknosis. alphaB-crystallin expression was significantly increased in perfused eyes. Perfusion with TGF-beta2 for 72 hours reduced outflow facility to approximately 60% of that of the medium-perfused control. TM cells adjacent to putative drainage pathways showed enlarged cisterns of rough endoplasmic reticulum (rER), a sign of active protein synthesis. Expression of alphaB-crystallin and FN mRNA were elevated by factors of 5 and 3, respectively. The proteins were upregulated by a factor of 2.5. In addition, TGF-beta2 upregulated PAI-1 (1.7-fold) and TSP-1 (1.6-fold) proteins, two factors shown to be TGF-beta2 responsive in human TM cell culture experiments. CTGF expression was not altered. CONCLUSIONS: These new ultrastructural investigations indicate that the cribriform and subendothelial regions of the porcine TM have an architecture similar to that of the primate TM. The biochemical and physiological response to TGF-beta2 was identical with that described in human TM cell culture and anterior chamber perfusion. The porcine anterior chamber perfusion model is valid for the human system.

[Structural changes of the anterior chamber angle in primary congenital glaucoma with respect to normal development]. / Cambios estructurales del ángulo de la cámara anterior en el glaucoma congénito. Comparación con el desarrollo normal.

PURPOSE: To compare findings of normal angles with those from primary congenital glaucoma in order to clarify the pathogenic mechanisms of the disease and to explain the success of surgical treatment in some of these patients. METHODS: Adult normal eyes from cadavers and fragments of surgical trabeculectomies from patients with primary congenital glaucoma previously treated with goniotomy were studied. Eyes were processed for examination using light microscopy and scanning electron microscopy techniques. RESULTS: The following was evident in congenital glaucoma: 1) high iris insertion; 2) no observable pre-trabecular membrane, but enlarged trabeculae with diminished inter-trabecular spaces; 3) Schlemm's canal (SC) apparently normal, with vacuoles in the wall indicating normal functioning; 4) sectioning of the abnormal trabecular tissue during goniotomy allowed repositioning of the angle structures and hence the appearance of the angular recess. CONCLUSIONS: Anomalies of the trabecular structures in primary congenital glaucoma do not always parallel an abnormal development of the SC and the collector channels. This fact could explain the success of goniotomy in this type of glaucoma.

Urate deposition in the iris and anterior chamber.

OBJECTIVE: To report on a patient with clear gelatinoid deposits on the iris and in the anterior chamber (AC). DESIGN: Observational case report. METHODS: Examination of AC aspirate and iris and conjunctival biopsies by light and transmission electron microscopy. MAIN OUTCOME MEASURES: Clinical and histopathological findings. RESULTS: Analysis of the aqueous humor and iris ultrastructure disclosed the presence of urate deposits. CONCLUSIONS: Urate deposition in the iris and anterior chamber rarely occurs.

Scanning electron microscope study of the rabbit anterior chamber angle.

The three-dimensional fine structure and the collagenous framework of the anterior chamber angle (chamber angle) of albino rabbits, which does not posses a Schlemm's canal, were examined, with or without NaOH maceration, by scanning electron microscopy. The chamber angle is ill defined because the deep ciliary cleft appears parceled by iris pillars. The collagenous framework of the pectinate ligaments and iris pillars arising from the iris root join to the collagen bundles of the trabecular sheet, and the surface of the ciliary cleft is covered by an endothelial cell layer that screens the trabecular meshwork. Round openings are apparent in the recesses of the ciliary cleft, with junctions between more superficial or deeper trabecular sheets resulting in direct communication between adjacent trabecular spaces. Openings of the angular aqueous plexus/sinus in place of Schlemm's canal were seen on the inner surface of the corneosclera after removing the trabecular meshwork. The framework of the trabecular sheet is basically formed of circumferentially arranged flat collagen bundles and reticularly diverged narrow collagen bundles extending from them. There is no shift between collagen bundles of the trabecular meshwork and the corneosclera, suggesting a frail connection between the two tissues.

Effect of microkeratome suction during LASIK on ocular structures.

PURPOSE: To study the effect of microkeratome suction on ocular structures during LASIK. DESIGN: Observational, prospective case series. PARTICIPANTS: Twenty-one eyes of 11 patients with myopia or astigmatic myopia (8 females, 3 males) were included. The mean patient age was 36.3 years (median, 37 years; range, 24-48 years), and the mean spherical equivalent was -5.03 diopters (D) (median, -4.63 D; range, -2.38 to -8.38 D). METHODS: We performed preoperative and intraoperative A-scan ultrasonography during application of suction using the Hansatome microkeratome (Bausch & Lomb Surgical, Munich, Germany) to create corneal flaps during LASIK. We also performed preoperative and postoperative B-scan ultrasonography of the posterior ocular segment with special attention to the presence and size of posterior vitreous detachment (PVD). MAIN OUTCOME MEASURES: We measured changes in the axial length, anterior chamber depth, lens thickness, and vitreous distance (distance from the posterior lens capsule to the posterior pole) during application of the microkeratome suction ring and recorded new occurrences of or increases in the size of the PVD after surgery. RESULTS: The lens thickness decreased (mean change, -0.20 mm; P = 0.001; 95% confidence interval [CI], -0.11 to -0.30) in 18 eyes during application of the suction ring. The vitreous distance increased (mean change, 0.20 mm; P = 0.004; 95% CI, 0.08-0.32) in 16 eyes. No statistically significant changes were found in the anterior chamber depth (P = 0.75) or axial length (P = 0.51). After surgery, 3 of 14 eyes (21.4%) experienced PVD that did not have echographic signs of PVD before surgery. Of 7 eyes with preoperative PVD, the PVD enlarged in 1 eye (14.3%). CONCLUSIONS: During application of microkeratome suction, the lens thickness decreases, whereas the vitreous distance increases, suggesting anterior traction on the posterior segment. The relationship between the observed PVD and LASIK merits further investigation.

[Ultrasound biomicroscopy in pigmentary glaucoma]. / Estudio de glaucoma pigmentario mediante biomicroscopia ultrasónica.

OBJECTIVE: To study the anterior chamber in pigmentary glaucoma by anterior ultrasound biomicroscopy (UBM), and to determine the effect of the YAG-laser iridotomy on intraocular pressure (IOP) and the iris morphology in pigmentary glaucoma. MATERIAL AND METHODS: Seven patients (14 eyes) with a diagnosis of pigmentary glaucoma were studied. YAG-laser iridotomy was performed on all the patients with demonstrable iris concavity by UBM, performing UBM one week post-iridotomy and control of the IOP at one week, six months and at one year following treatment. RESULTS: The existence of iris concavity was demonstrated in 6 of the 7 patients (12 of the 14 eyes), performing a YAG-laser iridotomy in all of them. Remission of the iris concavity was observed in 5 of the 6 patients (10 of the 12 eyes) and good control of the IOP was achieved without additional topical treatment in 3 (6 eyes). At one year, the number of drugs needed for IOP control decreases (p<0,005, Wilcoxon test, correction for small samples). CONCLUSIONS: In our sample, the YAG-laser iridotomy rectifies the iris concavity present in pigmentary glaucoma, reducing the IOP and the number of drugs needed for its control.