Lens Opacity, Thickness, and Position in Subjects With Acute Primary Angle Closure
Singapore National Eye Centre, Singapore. Journal of Glaucoma
(Impact Factor: 2.11).
07/2006; 15(3):260-3. DOI: 10.1097/01.ijg.0000212212.10395.76
To compare lens thickness (LT), lens position (LP), relative lens position (RLP), and degree and type of lens opacity between affected and fellow eyes of subjects with acute primary angle closure (APAC) to identify any differences in lens characteristics that may be contributory to the acute episode. In addition, axial length (AL) and anterior chamber depth (ACD) measurements were evaluated.
Seventy-three study subjects with unilateral APAC were treated with sequential laser iridotomy (LI) in both eyes. Two weeks after LI, ACD, LT, and AL measurements were made in both eyes using ultrasound pachymetry. LP was defined as ACD+1/2LT and RLP as LP/AL. The Lens Opacity Classification III (LOCS III) System was used for grading lens opacity.
The subjects were 90% Chinese and 63% female. Mean age was 61.0+/-10.9 years. Significant differences between the affected and fellow eyes were found in the ACD (2.11+/-0.35 vs 2.18+/-0.23; P=0.02) and LP (4.61+/-0.47 vs 4.75+/-0.29; P=0.02). Cortical opacity was greater in fellow eyes (0.32+/-0.72 vs 0.53+/-0.95; P=0.02). There was no difference in LT, RLP, or degree of lens opacity in the nuclear and posterior subcapsular regions.
Compared with fellow eyes, APAC-affected eyes have shallower ACD, more anterior LP, and less cortical opacity. These differences may be contributory to APAC.
Available from: M Reza Razeghinejad
- "Six measurements were performed per subject; if the standard deviation (SD) of these measurements was 0.12 mm or greater, all six readings were discarded and the process was repeated until the SD was less than 0.12 mm.14 The measured parameters were used to calculate corrected ACD (CACD=ACD-CCT), lens-axial length factor (LAF=LT/AL×10), lens position (ACD+½LT), relative lens position (RLP=[ACD+½LT]/AL×10), and corrected lens position (CLP=CACD+½ LT).11,15 "
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ABSTRACT: To compare ocular biometric parameters in primary angle closure suspects (PACS), primary angle closure glaucoma (PACG) and acute primary angle closure (APAC).
This cross-sectional study was performed on 113 patients including 33 cases of PACS, 45 patients with PACG and 35 subjects with APAC. Central corneal thickness (CCT), axial length (AL), anterior chamber depth (ACD) and lens thickness (LT) were measured with an ultrasonic biometer. Lens-axial length factor (LAF), relative lens position, corrected ACD (CACD) and corrected lens position were calculated. The parameters were measured bilaterally but only data from the right eyes were compared. In the APAC group, biometric parameters were also compared between affected and unaffected fellow eyes. Logistic regression analysis was performed to identify risk factors.
No statistically significant difference was observed in biometric parameters between PACS and PACG eyes, or between affected and fellow eyes in the APAC group (P>0.05 for all comparisons). However, eyes with APAC had thicker cornea (P=0.001), thicker lens (P<0.0001), shallower ACD (P=0.009), shallower CACD (P=0.003) and larger LAF (P<0.0001). Based on ROC curve analysis, lower ACD, and larger LT, LAF and CCT values were associated with APAC. In the APAC group, LAF (P<0.0001) and CCT (P=0.001) were significant risk factors.
This study revealed no significant difference in biometric characteristics in eyes with PACS and PACG. However, larger LAF and CCT were predictive of APAC.
Available from: onlinelibrary.wiley.com
- "Because body height was correlated with the anterior chamber depth and because a shallow anterior chamber is the major risk factor for primary angle-closure glaucoma (Congdon et al. 1997; Lim et al.2006), one may assume that angle-closure glaucoma may be more prevalent in shorter individuals than in tall individuals . In a parallel manner, the tendency between short stature and marked hyperopia also points to an association between primary angleclosure glaucoma and shorter stature because marked hyperopia, parallel to a shallow anterior chamber, is a risk factor for angle-closure glaucoma (Congdon et al. 1997; Lim et al.2006). Correspondingly, the Beijing Eye Study suggested that shorter individuals have a higher prevalence of angleclosure glaucoma (Xu et al. 2007). "
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ABSTRACT: To determine whether anthropomorphic measurements are associated with ocular and general parameters.
The population-based Beijing Eye Study, which included 4439 participants (age > 40 years) out of 5324 individuals invited to be examined in 2001, was repeated in 2006 with 3251 (73.2% of 4439, or 61.1% of 5324) participants. The anthropomorphic measurements body height and weight, socioeconomic variables and ocular parameters were evaluated.
Of the 3251 individuals included in the study, measurements of body height and weight were available for 3214 (98.9%) participants. In multivariate analysis, body height was significantly associated with the systemic parameters higher level of education (p = 0.004), higher income (p < 0.001), lower body mass index (p < 0.001), lower systolic blood pressure (p = 0.012), higher diastolic blood pressure (p < 0.001), male gender (p < 0.001), lower age (p < 0.001) and living in an urban region (p < 0.001), and with the ocular parameter of a deep anterior chamber (p < 0.001). The association between marked hyperopia and low body height was statistically marginal (p = 0.11).
In adult Chinese, body height is associated with higher level of education, higher income, lower systolic blood pressure, higher diastolic blood pressure and lower body mass index, in addition to living in an urban region and being male. From an ophthalmic point of view, tall individuals had deeper anterior chambers. There was a tendency towards lower body height and marked hyperopia. Because the socioeconomic, systemic and ocular parameters examined influence the occurrence and therapy of ocular diseases, these data may be helpful in the assessment of risk factors and in the diagnosis and treatment of ocular diseases.
Available from: ncbi.nlm.nih.gov
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To evaluate the prevalence of primary iris and/or ciliary body cysts in eyes with shallow anterior chamber and their effect on the narrowing of the anterior chamber angle.
Among the general physical check-up population, subjects with shallow anterior chambers, as judged by van Herick technique, were recruited for further investigation. Ultrasound biomicroscope (UBM) was used to detect and measure the cysts located in the iris and/or ciliary body, the anterior chamber depth (ACD), the angle opening distance at 500 µm (AOD500), and the trabecular-iris angle (TIA). A-scan ultrasonography was used to measure the ocular biometry, including lens thickness, axial length, lens/axial length factor (LAF), and relative lens position (RLP). The effect of the cyst on narrowing the corresponding anterior chamber angle and the entire angle was evaluated by the UBM images, ocular biometry, and gonioscopic grading. The eye with unilateral cyst was compared with the eye without the cyst for further analysis.
Among the 727 subjects with shallow anterior chamber, primary iris and ciliary body cysts were detected in 250 (34.4%) patients; among them 96 (38.4%) patients showed unilateral single cyst, 21 (8.4%) patients had unilateral double cysts, and 42 (16.8%) patients manifested unilateral multiple and multi-quadrants cysts. Plateau iris configuration was found in 140 of 361 (38.8%) eyes with cysts. The mean size of total cysts was (0.6547 ± 0.2319) mm. In evaluation of the effect of the cyst size and location on narrowing the corresponding angle to their position, the proportion of the cysts causing corresponding angle narrowing or closure among the cysts larger than 0.8 mm (113/121, 93.4%) was found to be significantly higher than that of the cysts smaller than 0.8 mm (373/801, 46.6%), and a significant higher proportion was also found in the cysts located at iridociliary sulcus (354/437, 81.0%) than in that at the pars plicata (131/484, 27.1%). In evaluating the effect of the cyst on the entire anterior chamber angle, the eyes with multiple and multi-quadrants cysts manifested significant narrowing of the entire anterior chamber angle as compared with the eyes without cysts, based on the data analysis in comparison of TIA, AOD500, and gonioscopic grading evaluation. The unilateral single or double cysts in the eyes had no significant effect on narrowing of anterior chamber angle as compared with eyes without cysts. The iris and/or ciliary body cysts did not seem to affect the axial length, ACD, lens thickness, RLP, LAF.
The prevalence of primary iris and ciliary body cyst was 34.4% in the subjects with shallow anterior chamber. The cysts larger than 0.8 mm, locating at iridociliary sulcus, or multiple and extensive cysts were inclined to cause the angle narrowing or closure.
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