Anterior Chamber Depth In Eyes Research Articles

Age-related increase in lens thickness and changes in the profile of anterior chamber angle in patients with moderate and high axial hyperopia

PURPOSE. To determine the age-related increase in lens thickness (LT), decrease in anterior chamber depth (ACD) and anterior chamber angle (ACA) in patients with short axial length (APA) of the eyes.METHODS. The study included 100 patients (200 eyes) with short AL (23 mm or less), with a transparent lens or with initial stage of age-related cataract: 46 men and 54 women, aged 19 to 85 years. The LT and ACD, ACA parameters were assessed using optical coherence tomography.RESULTS. In the total population of patients, LT increased by an average of 32 μm per year. At the same time, ACD and ACA decreased by an average of 14 µm and 0.3° per year, respectively (p<0.001). In men, LT increased by 35 μm per year, while in women it increased by 29 μm per year, the difference was not statistically significant (p=0.071). But the decrease in ACA in men averaged 0.38° per year, while in women it was 0.23° per year, this difference was statistically significant (p=0.003). In addition, the rate of decrease in the ACD in men and women also differed statistically significantly: 18 µm versus 11 µm per year (p=0.018).CONCLUSION. 1. According to our data, the annual increase in LT in eyes with short AL averages 32 μm, the decrease in ACD and ACA is on average 14 μm and 0.3° per year, respectively.2. We did not find a statistically significant gender difference in the rate of annual increase in LT, although the rate of decrease in ACA and ACD in men turned out to be statistically significantly higher.3. The obtained data on the annual changes in such morphometric parameters as LT, ACA and ACD in eyes with short AL are key in the formation of primary angle-closure glaucoma (PACG). It may allow a more precise prediction of the timeline of an increased risk of PACG in each particular case.

Improving Accuracy of In-The-Bag Intraocular Lens Power Calculation in Adult Eyes with Unilateral Subluxated Lenses by Using the Anterior Chamber Depth of the Unaffected Eye.

This study aimed to determine the interchangeability of bilateral anterior chamber depth (ACD) in intraocular lens (IOL) power calculations for cataractous eyes and refractive outcomes using the unaffected fellow eye's ACD in subluxated crystalline lenses. The predicted postoperative spherical equivalent (SE) calculated using the Kane formula with and without fellow eye's ACD in 202 cataract patients was compared. Refractive outcomes of the newer formulas (the Kane, Barrett Universal II [BUII], and Pearl-DGS formulas) with affected eye's ACD and with unaffected fellow eye's ACD were compared in 33 eyes with lens subluxation (the affected eye) undergoing in-the-bag IOL implantation. The SD of the prediction error (PE) was assessed using the heteroscedastic method. In 202 paired cataractous eyes, no marked ACD difference was found bilaterally; the predicted SE obtained without the fellow eye's ACD was comparable with that calculated with the fellow eye one (p = 0.90), with a mean absolute difference of 0.03 ± 0.03 D. With the affected eye AL, keratometry, and ACD, the median absolute error (MedAE) was 0.38-0.64 D, and the percentage of PE within ±0.50 D was 30.30-57.58%. The unaffected eye's ACD improved the results (MedAE, 0.35-0.49 D; the percentage of PE within ±0.50 D, 54.55-63.64%). The SDs of the BUII (0.82 D) and Pearl-DGS formulas (0.87 D) with the affected eye's ACD were significantly larger than those of the Kane and Pearl-DGS formulas (both 0.69 D) with the unaffected eye's ACD. Bilateral ACD was interchangeable in IOL power calculation for cataractous eyes when using the Kane formula. Unaffected eye's ACD in lieu of affected eye's ACD can enhance the accuracy of newer formulas in patients with unilateral subluxated lenses undergoing in-the-bag IOL implantation.

Interchangeability of bilateral anterior chamber depth in intraocular lens power calculation and its application in unilateral lens subluxation

Aims/Purpose: To assess the interchangeability of bilateral anterior chamber depth (ACD) in intraocular lens (IOL) power calculation, and to evaluate whether using the unaffected fellow eye's ACD can enhance refractive results in unilateral lens subluxation.Methods: Axial length (AL), keratometry (K) and ACD were obtained by IOLMaster 700. In cataract surgery candidates (Group 1), the virtual implantation of the same IOL model was used. The predictive results closest to the Plano of the Kane formula, using the right eye's biometry (AL, K and ACD), served as a benchmark. The results of the corresponding IOL power were further calculated by substituting the left eye's ACD for the right eye's one and compared with the benchmark. Eyes with unilateral lens subluxation (Group 2) underwent in‐the‐bag IOL placement after the capsular hook(s) implantation, with refraction conducted at least 1 month post‐operatively. Prediction errors (PE) of the Kane formula with or without the unaffected fellow eye's ACD were compared.Results: 392 eyes of 196 patients were analysed, including 173 candidates and 23 patients with unilateral subluxated lenses. In Group 1, there was no significant difference in bilateral ACD (p = 0.30). The predictive refraction using the right eye's ACD was −0.16 ± 0.10 diopter (D), and that obtained by the left eye's one was −0.16 ± 0.11 D (p = 0.64), with an absolute difference of 0.03 ± 0.03 D. In Group 2, the ACD was 2.89 ± 0.86 mm of the affected eye and 3.14 ± 0.37 mm of the fellow eye (p = 0.17). The median absolute PE, mean absolute PE and the percentage of PEs within ±0.50 D using the affected eye's ACD were 0.50 D, 0.59 D and 52.17%. Using the unaffected eye's ACD improved the outcomes to 0.45D, 0.52 D and 60.87%.Conclusions: Bilateral ACD values are interchangeable in routine IOL power calculation, and using the unaffected fellow eye's ACD can improve its accuracy in cases of unilateral lens subluxation undergoing in‐the‐bag IOL implantation.

Short-term Changes in Anterior Chamber Depth after Traumatic Hyphema

Purpose: To analyze short-term changes in anterior chamber depth (ACD) immediately and 1 month after traumatic hyphema.Methods: Thirty-two patients with traumatic hyphema treated from October 2015 to July 2019 were retrospectively reviewed. Nineteen were followed-up for 1 month. The ACDs were measured using an IOL Master 500 platform and the differences between the affected and contralateral eyes immediately after trauma and 1 month after treatment analyzed. The ACD differences between the affected and contralateral eyes of those with gross and microscopic hyphema and the correlations between the ACD differences of the two eyes were analyzed by age.Results: The average age was 36.0 ± 14.2 years and 24 patients were male (75%). The ACDs of affected eyes were greater than those of contralateral eyes both immediately after trauma (3.81 ± 0.38 vs. 3.55 ± 0.43 mm; p = 0.021) and 1 month after trauma (3.73 ± 0.37 vs. 3.61 ± 0.37 mm; p = 0.001). The ACD gaps and ACD/axial length ratios (%) did not differ significantly between the injured and contralateral eyes of the gross and microscopic hyphema groups immediately after trauma (p = 0.951/0.981). The ACDs of affected eyes decreased 1 month after trauma compared to immediately after trauma (3.73 ± 0.37 vs. 3.87 ± 0.40 mm; p = 0.013). The ACD difference immediately after trauma increased significantly with older age (R = 0.387, p = 0.018).Conclusions: The ACDs of eyes with traumatic hyphema increased significantly compared to those of the contralateral eyes immediately after trauma. The ACDs decreased after treatment but 1 month later were still significantly greater than the ACDs of the contralateral side.

Anterior Segment Characteristics of Eyes with Anterior Chamber Depth Less than 2.8mm and Axial Length Greater than 25mm.

This study aimed to investigate anterior segment parameters of eyes, with anterior chamber depth (ACD) less than 2.8mm and axial length greater than 25.0mm. This cross-sectional study included 180 myopic eyes of 180 consecutive patients with axial length greater than 25.0mm. Patients were divided into low ACD (ACD < 2.8mm, n = 56) and normal ACD (ACD ≥ 2.8mm, n = 124) groups. Anterior segment parameters were measured using Scheimpflug imaging and ultrasound biomicroscopy. A general linear model was used to compare parameters between the two groups, after adjusting for age and spherical equivalent. Compared with the normal ACD group, the low ACD group had lower values for the following parameters: corneal diameter, trabecular-anterior iris surface angle, angle-opening distance at 500μm, anterior chamber volume, anterior chamber width, anterior vault, iris thickness at 500μm, ciliary sulcus-to-sulcus diameter, distance between cornea and sulcus, trabecular-ciliary process distance, maximum ciliary body thickness, ciliary process length, relative anterior vault, relative distance between cornea and sulcus, and relative lens position (general linear model, p < 0.05). In contrast, central corneal thickness, iris curvature, lens thickness, lens vault, and iris-ciliary angle were greater in the low ACD group (general linear model, p < 0.05). A smaller anterior segment, as well as a thicker and more anteriorly positioned lens, may correlate with shallow ACD in eyes with long axial length.

Changes in the Postoperative Anterior Chamber Depth in Eyes Following Phacovitrectomy in Several Vitreoretinal Diseases

Aim: To investigate the difference in postoperative Anterior Chamber Depth (ACD) following phacovitrectomy depending on the type of the vitreoretinal diseases, measured using optical biometry. Methods: We investigated 14 eyes of 14 patients (11 males, 3 females; mean age 59.4 ± 8.4 years) with Rhegmatogenous Retinal Detachment (RRD) without macular involvement who underwent phacovitrectomy (RRD group), 14 eyes of 14 patients (10 males, 4 females; mean age 68.4 ± 4.7 years) with a macular hole (MH) who underwent phacovitrectomy (MH group), 24 eyes of 24 patients (14 males, 10 females; mean age 66.5 ± 7.6 years) with Epi Retinal Membrane (ERM) who underwent phacovitrectomy (ERM group), and 42 eyes of 29 patients (15 males, 14 females; mean age 71.4 ± 11.8 years) without macular disease who underwent cataract surgery (cataract group). ACD was measured prior to surgery and one month after surgery using optical biometry and was compared between groups. Results: The mean difference in ACD (postoperative ACD minus preoperative ACD) was 0.68 ± 0.38 mm in the RRD group, 1.12 ± 0.32 mm in the MH group, 1.04 ± 0.56 mm in the ERM group, and 1.00 ± 0.47 mm in the cataract group. Postoperative ACD in the RRD group was shallower compared to the other groups. Conclusion: Postoperative ACD in patients with RRD is shallower compared to other groups, including patients with MH, making it one of the suspected causes of myopic shift in patients with RRD.

Correlation between Axial Length and Anterior Chamber Depth in Eyes with High, Low and Average Axial Length

Abstract Background To achieve optimal refractive outcomes after cataract surgeries, accurate IOL power calculation is mandatory. IOL power is calculated using preoperative biometric measurements such as AL, corneal power, ACD and an estimation of postoperative effective lens position. Choosing the formula of IOL calculation depends mainly on AL and ACD. Objective The objective of this study is to investigate the correlation between AL and ACD in short eyes, normal eyes and long eyes. Patients and Methods The study was conducted at Ain Shams University Hospitals after the approval of the research ethical committee in the Faculty of Medicine, Ain Shams University. Study Period: 6 months (from July 2018 to January 2019). Results The results of our study showed that the correlation between the axial length and the anterior chamber depth among short eyes was statistically significant and they were negatively correlated, while no statistically significant correlation existed between AL and ACD in normal and long eyes. Discussion IOL power is calculated using preoperative biometric measurements such as AL, corneal power, ACD and an estimation of postoperative effective lens position. In the study by Holladay, 82% had normal AL and only 0.9% of patients had short eyes. Holladay et al. found that among patients with long eyes, 90% have normal ACD, 10% have high ACD and none of them have short ACD. In the group of patients with normal AL, they found that 90% of patients had normal ACD, none of them had low ACD and 10% had high ACD. In patients with short eyes they found that 20% have low ACD, 80% have normal ACD and none of them have high ACD. Sedaghat et al. documented that linear relationship was only seen in patients with normal AL and not in short and long sighted patients. Chang and Lau have concluded in their study that there was no statistically significant correlation between AL and ACD in eyes with AL of 27.5 mm or greater while positive statistically significant correlation existed in eyes shorter than 27.5 mm. Our study included ninety eyes of patients presenting for IOL or phakic lens implantation in Ain Shams University Hospitals. Patients were divided into three groups according to the AL; the short, normal and long eyes with AL ≤ 22 mm, &amp;gt; 22 mm and &amp;lt;24.50 mm and ≥24.50 mm, respectively. AL and ACD of each patient were measured using The ZEISS IOL Master 500. The results shows that the correlation between the axial length and the anterior chamber depth among short eyes is statistically significant and they are negatively correlated (r = -0.458. P value 0.011), while no statistically significant correlation exists between AL and ACD in normal and long eyes, i.e.: when AL &amp;gt; 22 mm. This lack of correlation might influence the ELP predictions in third generation formulas, which do not consider the preoperative ACD. Our study results agree with most of the previous studies regarding long eyes &amp;gt;27.5 mm that there is no statistically significant correlation between AL and ACD. While in short eyes it disagrees with Chang and Lau who concluded that there was no statistically significant correlation in short eyes and Sedaghat et al. who showed positive correlation between AL and ACD in short eyes. Our study results disagrees with most of the previous studies regarding normal eyes showing that there is no statistically significant correlation between AL and ACD in normal eyes, while previous studies concluded that a positive linear correlation exists. Conclusion The AL and ACD are inversely related in short eyes with AL ≤ 22 mm while no correlation exists in normal and long eyes with AL &amp;gt; 22 mm.

Effect of anterior chamber depth on predictive accuracy of seven intraocular lens formulas in eyes with axial length less than 22 mm.

PurposeThis study aimed to evaluate whether different anterior chamber depth (ACD) affects the predictive accuracy of intraocular lens formulas in eyes with axial length (AL) less than 22 mm.MethodsEighty-five eyes of 85 patients with AL less than 22 mm were included in this retrospective study, which were divided into three groups: Group 1, ACD less than 2.4 mm; Group 2, ACD between 2.4 and 2.9 mm; and Group 3, ACD greater than 2.9 mm. Optical biometry with partial coherence interferometry was performed in all cases. The median absolute error (MedAE) was compared by Friedman’s test, using the optimized lens constant, among seven formulas (Barrett Universal II, Haigis, Hill-RBF, Hoffer Q, Holladay 1, Holladay 2, and SRK/T) in each group.ResultsFriedman’s test showed no significant difference in MedAE among all formulas in Groups 1 and 3. However, as the Haigis formula had the highest MedAE and lowest percentage of eyes within ±0.25 Diopter, it is least preferred in Group 1. On the contrary, in Group 3 it fared the best, having the least MedAE and highest percentage of eyes within ±0.25 Diopter. In Group 2, Friedman’s test gave significant difference, and post-hoc analysis showed statistical superiority of Haigis over the Holladay 1 (p=0.02), Holladay 2 (p=0.01), Hill-RBF (p=0.04), and SRK/T (p=0.02) formulas. However, there was no statistical difference between the Barrett Universal II, Haigis, and Hoffer Q formulas.ConclusionConsidering the ACD in eyes with AL less than 22 mm, Haigis is the preferred formula while SRK/T proved to be the worst formula in Groups 2 and 3.

Correlation between ocular axial length and anterior chamber depth and a differential analysis in same-sized eyes

Purpose: To study correlation between ocular axial length and anterior chamber depth in eyes and to differentially analyse strength of this correlation in eyes with near-equal axial length. Materials and Methods: We conducted an observational study where keratometry and optical biometry records of 872 patients reporting for cataract surgery were taken. A comparative analysis using Optical Biometry (Zeiss IOL master) for pre-operative measurement of Axial length (AL), Anterior chamber depth (ACD) and calculated IOL power was done. Statistical Analysis: Data was analysed to determine overall correlation between two parameters. Patients were then classified into various groups of near-equal AL for a differential comparison within the group. Kendall-Pearson product-moment correlation test was used to assess relationship between AL and ACD, overall and within each subgroup. A P-value

Longitudinal Change in Peripheral Anterior Chamber Depth of Eyes with Angle Closure after Laser Iridotomy.

Purpose To investigate longitudinal changes in peripheral anterior chamber depth (pACD) of eyes with angle closure after laser iridotomy (LI) and factors related to prognosis. Design Retrospective cohort study. Methods Eyes with primary angle closure (PAC), acute PAC, or chronic angle closure glaucoma (CACG) that underwent LI (LI group) and eyes that underwent phacoemulsification and intraocular lens insertion (PEA + IOL group) were employed. Longitudinal changes in pACD were evaluated with a scanning peripheral anterior chamber depth analyzer (SPAC) in addition to routine ophthalmic examination. Results Forty-eight eyes of LI groups (69.8 ± 8.5 years) and 21 eyes of PEA + IOL group (65.6 ± 12.7 years) were enrolled. Mean follow-up times of LI group and PEA + IOL group were 43.4 ± 12.7 months and 36.5 ± 2.5 months, respectively. LI significantly increased pACD as indicated by the SPAC grade change from 3.8 ± 1.1 to 4.6 ± 1.2 (p < 0.001). However, SPAC grade was gradually reduced and reached the pre-LI level by the third year of follow up. PEA + IOL also significantly increased SPAC grade from 6.7 ± 1.6 to 8.7 ± 2.0 (p < 0.001), but no time-related change was observed. Twenty-three cases of LI group presented with deterioration of glaucoma control. The type of angle closure, plateau iris configuration, peripheral anterior synechia, and glaucomatous visual field defects were significantly associated with prognosis of glaucoma after LI. Conclusions Peripheral ACD is temporarily deepened by LI, but returns to the pre-LI level in approximately three years. The type of angle closure and some factors may be related to glaucoma prognosis after LI.

Interchangeability among five devices that measure anterior eye distances

PurposeThe aim was to study the interchangeability of various devices that measure anterior chamber depth (ACD) and white‐to‐white (WTW) distance.MethodsEighty right eyes of eighty patients aged 20 to 40 years were included. Their spherical equivalent ranged from ‐4.25 to +1.00 dioptres. Each eye's ACD and the WTW distance were measured using the following devices: a Castroviejo surgical calliper, CA‐200F Corneal Analyser, Orbscan II, Pentacam HR and IOLMaster 500.ResultsThe Pentacam HR measured significantly greater ACD (p < 0.01) than the other two devices, whereas IOLMaster 500 and Orbscan II yielded comparable (p > 0.01) distances. Nonetheless, in every device comparison, the mean difference was within clinically acceptable limits. The device comparison showed that for WTW distance measurements IOLMaster 500 yields the greatest value (p < 0.01), whereas CA‐200F Corneal Analyser yields the smallest one (p < 0.01).ConclusionPentacam HR, Orbscan II and IOLMaster 500 can be used interchangeably to measure ACD, whereas Orbscan II, IOLMaster 500, Castroviejo surgical calliper and CA‐200F Corneal Analyser cannot be considered interchangeable, when it comes to measuring WTW distance.

Measurements of anterior chamber depth, white-to-white distance, anterior chamber angle, and pupil diameter using two Scheimpflug imaging devices.

To compare the ocular anterior chamber depth, white-to-white distance, anterior chamber angle, and pupil diameter, as measured with two different Scheimpflug imaging devices. This transversal study included 80 right eyes from 80 subjects aged from 20 to 40 years. Their spherical equivalents ranged from -4.25 to +1.00 diopters (D). Each eye's anterior chamber depth, white-to-white distance, anterior chamber angle, and pupil diameter, were measured for far vision using both the Galilei G4 (double Scheimpflug camera) and the Pentacam HR (single Scheimpflug camera) systems. Mean anterior chamber depths were calculated as 3.12 ± 0.23 mm and 3.19 ± 0.24 mm when measured with the Galilei G4 and the Pentacam HR, respectively. The mean white-to-white distance measured was 11.84 ± 0.31 mm and 11.90 ± 0.43 mm when measured with the Galilei G4 and the Pentacam HR, respectively. Mean pupil diameters were measured as 3.22 ± 0.58 mm and 3.22 ± 0.52 mm when measured with the Galilei G4 and the Pentacam HR, respectively. Finally, the mean anterior chamber angle was 34.30 ± 2.86 degrees when it was measured with the Galilei G4, and 39.26 ± 2.85 degrees when measured with the Pentacam HR. A comparative analysis revealed that the Galilei G4 yielded a significantly lower (P<0.05) measurement for the anterior chamber depth, anterior chamber angle, and pupil diameter, than the Pentacam HR system. Comparable values (P>0.05) for both devices were obtained for the white-to-white distance measurements. The Galilei G4 and Pentacam HR Scheimpflug systems cannot be used interchangeably because they produce significant measurement differences.

Changes in anterior chamber depth following vitrectomy

Background Anterior segment morphometry is crucial for ophthalmologists to understand the visual outcomes of cataract surgery, keratorefractive surgery, as well as some other anterior segment disorders. Previous reports in literature have shown that anterior chamber depth (ACD) may shift slightly after vitrectomy. This study aimed to characterize the short-term changes in ACD in eyes after vitrectomy by means of A-scan ultrasound. Methods A prospective case series study was carried out on 29 eyes of 29 patients who underwent vitrectomy as the sole procedure. ACD was measured using A-scan ultrasound biometry shortly before vitrectomy and 1 week, 1 month, and 3 months after the surgery. Postoperative ACDs were compared with baseline. Results Twenty-nine patients (16 males and 13 females) were enrolled in the study, with mean age of (50±11) (25-65) years. Twenty-three eyes of 23 patients were vitrectomized for vitreous hemorrhage (VH) and the other six were operated for idiopathic epiretinal membrane (ERM). The mean preoperative ACD of the VH eyes was (2.98±0.38) mm. No significant difference was found between the ACD of the VH eyes and their fellow eyes (P=0.058). The average preoperative ACD in the ERM eyes was (2.94±0.31) mm, which was statistically deeper than that of their fellow eyes ((2.85±0.28) mm, P=0.008). No statistical difference was found in the postoperative average ACD of the VH eyes compared with baseline. In the ERM group, the postoperative ACD in the surgical eyes was still statistically deeper than the fellow eyes 1 week after surgery (P=0.034). However, such statistical difference disappeared at 1 or 3 months postoperative (P=0.186 and 0.682). Conclusions ERM may induce deepening of the ACD, which can be recovered by uneventful vitrectomy. VH does not cause shift of ACD, neither does vitrectomy.

Effects of Postural Variation on Anterior Chamber Depth in Pseudoexfoliative Eyes with Normal Intraocular Pressure

Purpose: Pseudoexfoliation (PEX) is a condition characterized by widespread intraocular and systemic production and deposition of an abnormal fibrillar extracellular material. Zonular instability is frequently associated with PEX. Anterior chamber depth (ACD) and intraocular pressure (IOP) changes in normotensive eyes with PEX after prone position was investigated in this study.Methods: Thirty subjects with normotensive pseudoexfoliative eyes and 30 healthy control subjects were enrolled. None of the eyes had cataract or posterior synechia. Central ACD, axial length (AL), and IOP were measured 5 min after supine and prone positions by using A-scan ultrasonography and TonoPen.Results: Mean ACD decreased from 2.89 ± 0.27 mm to 2.71 ± 0.23 mm in eyes with PEX and from 2.94 ± 0.25 mm to 2.84 ± 0.30 mm in normal eyes with postural change. The ACD decreased significantly in both group of eyes in prone position (p < 0.001 in PEX group, p = 0.005 in normal group), but the decrease in ACD in eyes with PEX was significantly greater than the decrease in normal control eyes (p = 0.03). Mean IOP was 16.9 ± 2.1 mmHg after supine position and 17.1 ± 2.04 mmHg after prone position in eyes with PEX, 16.1 ± 2.7 mmHg after supine position and 16.3 ± 2.6 mmHg after prone position in normal eyes. Postural changes in IOP and AL were not statistically significant in both groups of eyes (p = 0.096 in the PEX group and p = 0.484 in the normal group for IOP; p = 0.177 in the PEX group and p = 0.276 in the normal group for AL).Conclusion: The lens is more mobile in pseudoexfoliative eyes than normal eyes after supine to prone position. Although the ACD of pseuodoexfoliative eyes decreased statistically significantly after 5 min of prone position, IOP did not change significantly.

Accuracy of Intraocular Lens Power Calculations According to the Formulas and Anterior Chamber Depth in Short Eyes

Purpose: To evaluate the accuracy of intraocular lens (IOL) power calculations according to the chosen formulas and anterior chamber depths in eyes with short axial lengths. Methods: A retrospective analysis was performed on 57 eyes of 50 patients (axial length axial length

Morphological changes of the anterior segment after laser peripheral iridotomy in primary angle closure

To study changes in anterior segment morphology after laser peripheral iridotomy (LPI) in primary angle closure (PAC) using anterior segment optical coherence tomography (AS-OCT). LPI was performed on 15 consecutive primary angle closure patients (15 eyes). AS-OCT was used to record the morphology of the anterior segment before and after LPI. The central anterior chamber (AC) depth, the diameter of the pupil, the lens thickness, and the AC volume were measured. The peripheral AC depth and the configuration of iris were also observed qualitatively. The intraocular pressure (IOP) was measured by Goldmann applanation tonometer. The mean central AC depth was 1.939+/-0.228 and 1.970+/-0.235 mm before and after LPI, respectively, increasing by 1.6%, P=0.001. In all eyes but two, the central AC depth increased. The AC volume changed significantly after LPI (73.86+/-14.58 vs 84.14+/-17.45 microl, P<0.001) and it increased in all eyes. The iris flattened and the peripheral AC deepened after LPI in all 15 eyes. The mean IOP was 17.8+/-3.3 and 15.9+/-3.1 mmHg before and after LPI, respectively, P=0.042. The changes of pupil diameter and lens thickness were not statistically significant. LPI leads not only to the increase of peripheral anterior chamber depth and anterior chamber volume but also to an increase of central anterior chamber depth in eyes with primary angle closure.

Insulinlike Growth Factor I Affects Ocular Development: A Study of Untreated and Treated Patients with Laron Syndrome

To evaluate the ocular dimensions in patients with primary growth hormone receptor insensitivity (Laron syndrome [LS]) and to study the effect of supplemental insulinlike growth factor I (IGF-I) on ocular growth. Retrospective case series. Twelve patients with LS, 8 untreated (LS group) and 4 treated (LS-T group) with supplemental IGF-I, and 30 healthy controls. Ocular dimensions and refraction were measured, and a full ophthalmologic examination was performed. Differences in the average ocular dimension data among IGF-I-treated patients, untreated ones, and controls. The average axial length of eyes in the LS group was 21.94 mm (standard deviation [SD], 0.81). Corresponding values for the LS-T and control group eyes were 22.53 mm (SD, 1.74) and 23.20 mm (SD, 1.35) respectively. The average anterior chamber depth of eyes in the LS group was 2.55 mm (SD, 0.26). Corresponding values for eyes in the LS-T and control groups were 3.48 mm (SD, 0.09) and 3.84 mm (SD, 0.16) respectively. The average lens thickness of eyes in the LS group was 4.56 mm (SD, 0.36). Corresponding values for the LS-T and control groups were 3.77 mm (SD, 0.23) and 3.51 mm (SD, 0.25), respectively. The average corneal curvature of eyes in the LS group was 46.9 diopters (D) (SD, 2.32). Corresponding values for the LS-T and control groups were 47.6 D (SD, 2.83) and 44.4 D (SD, 1.5), respectively. Insulinlike growth factor I seems to be an important regulator of ocular growth as documented in patients with primary growth hormone insensitivity. The mechanism of this observation should be investigated further.

Anterior chamber depth measurement: A-scan versus optical methods

Purpose: To evaluate methods of measuring anterior chamber depth (ACD) before and after cataract surgery. Setting: St. Erik’s Eye Hospital, Stockholm, Sweden. Methods: A-scan (BVI Axis) and Scheimpflug imaging (Nidek EAS-1000) were used to measure ACD preoperatively and 6 and 18 weeks after phacoemulsification with implantation of a poly(methyl methacrylate) (PMMA) intraocular lens (IOL) in 23 patients. Because of a large systematic difference between the 2 methods, measurement with Orbscan (Orbtek) and optical pachymetry (Haag-Streit) were included when measurements were repeated 36 weeks postoperatively. A t test for paired observations was used for statistical analysis. Results: Preoperatively, the mean A-scan measurements were significantly shorter than the Scheimpflug values: 3.05 mm ± 0.36 (SD) and 3.37 ± 0.35 mm, respectively ( P < .001). At 6 weeks, the difference was more pronounced: 3.73 ± 0.26 mm and 4.65 ± 0.33 mm, respectively ( P < .001). At 36 weeks, the A-scan and Scheimpflug values remained unchanged. The results of the Scheimpflug measurements were confirmed with optical pachymetry and Orbscan analysis. Conclusions: There was good agreement between results obtained with 3 methods based on optical principles. Considering the basic and simple measurement principle of these instruments, they appear to provide the correct result. The A-scan equipment used in this study is unsuitable for determination of ACD in eyes with PMMA IOLs.

Does head positioning influence anterior chamber depth in pseudoexfoliation syndrome?

Phacodonesis can occur in pseudoexfoliation syndrome because of impaired zonular support. This study investigates whether the increased mobility of the lens influences anterior chamber depth in patients with pseudoexfoliation while assuming a prone position. Central anterior chamber depth was measured in 39 patients with clinically apparent unilateral pseudoexfoliation and elevated intraocular pressure. Patients were placed in a face-up position for 5 minutes, at which time anterior chamber depth and axial length were measured by A scan, and intraocular pressure was measured by Tonopen (Oculab, La Jolla, CA) in both eyes. The measurements were repeated on both eyes after 5 minutes in a face-down position. No significant differences in intraocular pressure or axial length between the prone and supine positions were found in either eye. Anterior chamber depth in eyes with pseudoexfoliation decreased from a mean of 3.08 mm in the supine position to a mean of 2.95 mm in the prone position, whereas mean anterior chamber depth in the fellow eyes decreased from 3.01 mm to 2.97 mm. The decrease in anterior chamber depth when facing down in the eyes with pseudoexfoliation was significantly greater than in the fellow eyes. In patients with clinically apparent unilateral pseudoexfoliation, the lens seems to be more mobile in the affected eye. This results in a shallower anterior chamber when the head is placed in a prone position. Whether this fact might potentially lead to transient pupillary block when engaging in activities such as facing down while reading warrants further study.

Ultrasound biomicroscopic study of ciliary body thickness in eyes with narrow angles

PURPOSE: To determine the ciliary body thickness and other biometric findings in eyes with narrow angles. METHODS: Eighteen otherwise normal eyes with narrow angles in 18 Japanese patients and 18 normal control eyes with open angles in 18 age-matched and sex-matched Japanese patients were studied. A-scan ultrasonography was performed to measure anterior chamber depth, lens thickness, axial length, and relative lens position. Ultrasound biomicroscopy was also performed to obtain measurements of the anterior ocular structures, including anterior chamber depth and ciliary body thickness at sites 1 mm and 2 mm posterior to the scleral spur (positions 1 and 2, respectively). RESULTS: Compared with normal control eyes, the narrow-angle eyes showed a shallower anterior chamber (narrow angle, 1.87 ± 0.27 mm; control, 2.69 ± 0.26 mm; P < .0001), a thicker lens (4.97 ± 0.49 mm, 4.26 ± 0.53 mm; P < .0001), a more anteriorly located lens (2.21 ± 0.13, 2.35 ± 0.14; P < .0001), a shorter axial length (22.70 ± 0.97 mm, 23.41 ± 0.86 mm; P = .012), and a thinner ciliary body (position 1: 454 ± 107 μm, 602 ± 86 μm; P < .0001; position 2: 203 ± 50 μm, 321 ± 68 μm; P < .0001). Lens thickness was significantly correlated with ciliary body thickness at positions 1 ( R 2 = 0.34; P = .0001) and 2 ( R 2 = 0.43; P < .0001). Anterior chamber depth was significantly correlated with ciliary body thickness at positions 1 ( R 2 = 0.48; P < .0001) and 2 ( R 2 = 0.56; P < .0001). CONCLUSION: Thinning of the ciliary body may be one of the important factors associated with the anterior location of the lens, the increased lens thickness, and the decreased anterior chamber depth in eyes with a narrow angle.