Iris Base Research Articles

Classifications of Qualitative Characteristics on Angle Configurations via Ultrasound Biomicroscopy in Acute Primary Angle Closure.

PurposeTo study the classifications of qualitative characteristics on the angle configurations in the acute primary angle closure (APAC) and fellow eyes by ultrasound biomicroscopy (UBM).MethodsA total of 131 patients (262 eyes) were researched retrospectively. The qualitative parameters from UBM images were classified into iris form (IF), ciliary body configuration (CBC), basal iris thickness (BIT), iris convexity (IC), iris insert (II), iris angulation (IA), ciliary body size (CBS) and ciliary body position (CBP). Comparative analyses between the APAC (case group) and fellow (control group) eyes were performed.ResultsThere were significant differences in IF, CBC, IC, II, CBS, CBP between the case group and control group in all quadrants (P<0.001). The IA of the case group and control group presented significant difference in all quadrants (P=0.001). However, there was not a significant difference in BIT between the case group and control group in all quadrants (P=0.495). The case group had fewer parallelogram-like and mushroom-like and more cone-like and hook-like CBCs than the control group (P<0.001).ConclusionMultiple ciliary body configurations can influence the stability of the lens and the anatomic configuration of the anterior chamber angle indirectly. New qualitative classification system of UBM may be more intuitionistic and refined to reflect the angle configurations to help clinical practice.

The ocular biometry characteristics of young patients with primary angle-closure glaucoma

BackgroundAlthough primary angle-closure glaucoma (PACG) mainly occurs in elderly people, diagnosis of PACG in young patients is not uncommon. So far, there is no article specialized on the ocular anatomical characteristics in these patients.In this study, ocular anatomical characteristics in young PACG patients are analyzed.MethodsIn this retrospective, comparative study, patients diagnosed with PACG and received ultrasound biomicroscopy (UBM) examination in our department were included. Patients were divided into two groups: a young group composed of patients ≤ 45 years and an old group composed of patients > 45 years. A-scan ultrasonography and ultrasound biomicroscopy (UBM) were used to measure ocular biometric parameters of patients in the two groups including axial length (AL), lens thickness (LT), central anterior chamber depth (ACD), anterior chamber width (ACW), angle opening distance 500 (AOD500), anterior chamber angle 500 (ACA500), iris thickness 1000 μm from the iris root (IT1000), iris thickness 500 μm from the iris root (IT500), trabecular-ciliary process angle (TCPA), trabecular-ciliary process distance (TCPD), scleral– ciliary process angle (SCPA), lens vault (LV), and pupil diameter (PD). Plateau iris (PI) and basal iris insertion were determined from UBM images, and the prevalence of PI and basal iris insertion were compared between the two groups. The incidence of postoperative malignant glaucoma (MG) was also determined in both groups and ocular anatomical predictors for the development of MG were evaluated in young PACG patients.ResultsOne hundred fifteen patients were included into young group and 480 patients were included into old group. The young group had shorter TCPD, shorter AL, narrower TCPA, narrower SCPA thinner Lens compared to the old group. There were no significant differences in ACD, AOD 500, ACA500, LV, IT500, IT1000, PD or ACW between the two groups. The prevalence of PI was 22.6% in old group and 66.1% in young group (P < 0.001). More young PACG patients displayed basal iris insertion compared to old PACG patients (P < 0.001). 87 patients in the young group and 201 patients in the old group underwent trabeculectomy in our study. Among these patients, 21 young patients and 11 old patients developed MG after trabeculectomy (P < 0.001).ConclusionsShorter AL, more anteriorly positioned ciliary body, higher prevalence of PI may be responsible for the etiology of young PACG patients. Our results suggest that shorter AL, shorter TCPD and narrower TCPA may be predictors for development of MG in young PACG patients after trabeculectomy.

Predictors of angle widening after laser iridotomy in Chinese patients with primary angle-closure suspect using ultrasound biomicroscopy.

To assess the predictive value of baseline parameters of ultrasound biomicroscopy (UBM) for angle widening after prophylactic laser peripheral iridotomy (LPI) in patients with primary angle-closure suspect (PACS). Angle-opening distance (AOD), trabecular iris angle (TIA), iris thickness, trabecular-ciliary process angle, and trabecular-ciliary process distance were measured using UBM performed before and two weeks after LPI. Iris convexity (IC), iris insertion, angulation, and ciliary body (CB) size and position were graded. Uni- and multivariate regression analyses were used to determine factors predicting the change in AOD (ΔAOD500, calculated as an angle width change before and after LPI) in all quadrants and in subgroup quadrants based on IC. In 94 eyes of 94 patients with PACS, LPI led to angle widening with increases in AOD500 and TIA (P<0.01). Multivariable regression analysis showed that IC (P<0.001), CB position (P=0.007) and iris insertion (P=0.049) were significantly predictive for ΔAOD500. All quadrants were categorized into extreme IC (27.8%), moderate IC (62.3%), and absent IC (9.9%) subgroups. The AOD500 increased by 220% and no other predictive factor was found in the extreme IC quadrants. The AOD500 increased by 55%, and baseline iris angulation was predictive for smaller changes in ΔAOD500 in the moderate IC quadrants. In PACS patients, quadrants with greater iris bowing predict substantial angle widening after LPI. Quadrants with a flatter iris, anteriorly positioned CB, and basal iris insertion are associated with less angle widening after LPI. Quadrants with iris angulation as well as a flatter iris configuration predict a smaller angle change after LPI.

Iris thickness and volume be measured using iris base instead of scleral spur as reference in anterior optical coherence tomography scan.

PURPOSE:To compare the iris parameters (iris thickness [IT] and volume) measured at different locations on iris determined using iris base (IB) and scleral spur (SS) in healthy Saudi eyes and factors affecting the differences.METHODS:Healthy eyes of Saudi persons were evaluated using anterior segment optical coherence tomography (AS-OCT). The IT was measured using Image J software and OCT scans in the horizontal axis in light on and light off condition. First IB was used as reference, and then, SS was used as reference for these measurements.RESULTS:One hundred healthy eye's AS-OCT scan was studied. The IT at the temporal side of the horizontal axis at 750 µ away from IB with lights on was 0.526 ± 0.08 µ, whereas it was 0.52 ± 0.08 µ from SS. The difference was significantly more in IB than SS method (P = 0.005). This difference if IT in SS and IB method was not affected by gender (Mann–Whitney P = 0.3), type of refractive error (K W P = 0.7), and level of illumination (K W P = 0.7).CONCLUSION:IT and IV measured using IB provided reliable data but overestimates compared to SS method. In the absence of SS visibility, IB could be alternative to assess iris parameters.

Qualitative Evaluation of the Iris and Ciliary Body by Ultrasound Biomicroscopy in Subjects With Angle Closure

To qualitatively analyze anterior chamber structures imaged by ultrasound biomicroscopy (UBM) in primary angle-closure patients. Subjects diagnosed as primary angle-closure suspect (PACS), primary angle-closure glaucoma (PACG), and previous acute primary angle closure (APAC) were recruited prospectively along with a group of normal controls. UBM was performed under standardized dark room conditions and qualitative assessment was carried out using a set of reference photographs of standard UBM images to categorize the various anatomic features related to angle configuration. These included overall and basal iris thicknesses, iris convexity, iris angulation, ciliary body size, and ciliary sulcus. A total of 60 PACS, 114 PACG, 41 APAC, and 33 normal controls were included. Patients were predominantly older Chinese females. After controlling the confounding effect of age and sex, eyes with overall thicker irides [medium odds ratio (OR) 3.58, thick OR 2.84] when compared with thin irides have a significantly higher likelihood of having PACS/PACG/APAC versus controls. Thicker basal iris component (medium OR 4.13, thick OR 3.39) also have higher likelihood of having angle closure when compared with thin basal iris thickness. Subjects with basal iris insertion, mild iris angulation, and large ciliary body have a higher OR of having angle closure. In contrast, the presence/absence of a ciliary sulcus did not influence the likelihood of angle closure. Eyes with thicker overall and basal iris thicknesses are more likely to have angle closure than controls. Other features that increase the likelihood of angle closure include basal iris insertion, mild iris angulation, and large ciliary body.

Qualitative assessment of ultrasound biomicroscopic images using standard photographs: the liwan eye study.

Objective. To classify anatomic features related to anterior chamber angles by a qualitative assessment system based on ultrasound biomicroscopy (UBM) images. Methods. Cases of primary angle-closure suspect (PACS), defined by pigmented trabecular meshwork that is not visible in two or more quadrants on static gonioscopy (cases) and systematically selected subjects (1 of every 10) who did not meet this criterion (controls) were enrolled during a population-based survey in Guangzhou, China. All subjects underwent UBM examination. A set of standard UBM images was used to qualitatively classify anatomic features related to the angle configuration, including iris thickness, iris convexity, iris angulation, ciliary body size, and ciliary process position. All analysis was conducted on right eye images. Results. Based on the qualitative grades, the difference in overall iris thickness between gonioscopically narrow eyes (n = 117) and control eyes (n = 57) was not statistically significant. The peripheral one third of the iris tended to be thicker in all quadrants of the PACS eyes, although the difference was statistically significant only in the superior quadrant (P = 0.008). No significant differences were found in the qualitative classifications of iris insertion, iris angulation, ciliary body size, and ciliary process position. The findings were similar when compared with the control group of eyes with wide angles in all quadrants. Conclusions. Basal iris thickness seems to be more relevant to narrow angle configuration than to overall iris thickness. Otherwise, the anterior rotation and size of the ciliary body, the iris insertion, and the overall iris thickness are comparable in narrow- and wide-angle eyes.

Effect of Age on the Development of a Latanoprost-Induced Increase in Iris Pigmentation

To study the effect of patient age on the incidence of latanoprost-induced increases in iris pigmentation. Prospective observational observer-masked study. Thirty-six patients younger than 60 years (group 1) and 36 patients older than 75 years (group 2) with primary open-angle glaucoma. We photographed both irises of each patient before and 6 months after unilateral latanoprost therapy. The basal iris colors were matched in both groups. Iris heterochromia identification at the 6-month evaluation of the photographs. Twenty-eight patients (77.78%) in group 2 developed an increase in iris pigmentation compared with eight patients (22.22%) in group 1 (P = 0.0001, chi-square test). Age seems to be an important risk factor for latanoprost-induced iris color change.

Gonioscopic findings in patients with type 1 neurofibromatosis (Von Recklinghausen disease).

Based on the known neurocristopathic etiology of type 1 neurofibromatosis (NF1) and the neuroectodermal embryologic derivation of the iridocorneal angle, we examined a sample of young patients affected with NF1 to see if they have evidence of underdevelopment of the angular region. We designed a case-controlled clinical study. Forty-two consecutive patients (42 eyes), 24 male and 18 female, affected with NF1 were recruited for the study. Forty-two eyes of 42 consecutive young patients (19 male and 23 female) served as a control group for the iridocorneal angle features studied. Indirect gonioscopy was performed by the means of a Goldmann lens. The intraocular pressure was measured with a Goldmann applanation tonometer. Photographs were taken of the anterior segment and of all the four quadrants of the iridocorneal angle to record the presence of abnormalities. The iridocorneal angle was graded according to the classification proposed by Spaeth. Evaluation of the angle also included the gonioscopic width of ciliary body band (CBB). In this study we found that 29 of 42 eyes (69%) of the NF1 group had mild anteriorization, even if within normal limits, of the iris insertion and abundant basal iris processes. The CBB was either invisible (54.84%) or very narrow (21.4%). Three NF1 patients had bilateral juvenile congenital glaucoma. It seems that patients affected with NF1 often have characteristic gonioscopic findings consistent with underdevelopment of the iridocorneal angle.

Cataract surgery in a patient with severe chronic iritis and corneal endothelial damage

We report a patient with broad anterior synechias and corneal endothelial damage. The patient had chronic iritis and cataracts secondary to the chronic iritis in both eyes. Because the right eye had broad anterior synechias and severe corneal endothelial damage, extracapsuiar cataract extraction and intraocular lens implantation were performed through the basal iris. Good postoperative visual acuity was obtained. The cornea showed little trauma from the surgery and remained clear 36 months postoperatively.