Comparison between post-operative anterior chamber depth after cataract alone and combined with 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.

Prediction of Postoperative Intraocular Lens Position with Angle-to-Angle Depth Using Anterior Segment Optical Coherence Tomography

Purpose: To predict the postoperative anterior chamber (AC) depth from the preoperative in situ position of the lens central clear zone (CCZ) using Scheimpflug slit photography. Methods: 111 eyes of 78 cases that underwent phacoemulsification and intraocular lens (IOL) implantation were examined. 748 eyes of 383 healthy subjects with transparent lenses were used as the control. Scheimpflug slit photography was done under maximal mydriasis, and biometry was performed on the photographs. Two types of acrylic IOLs (MA30BA and MA60BM, both from Alcon) were used in this study. The preoperative AC depth (L1), the distance between the anterior lens capsule and lens CCZ (L2) and the postoperative AC depth (I1) were determined. I2, the predicted postoperative AC depth, was then determined from a linear regression of L1 + L2 and I1. Results: L2 thickened by 0.014 mm/year, and L1 decreased by 0.016 mm/year in the transparent lenses. L1 + L2 changed little with aging in both cataractous and transparent lenses. L1 + L2 and I1 showed a linear correlation with r = 0.80 in the MA30BA and r = 0.77 in the MA60BM groups. The mean error values between I1 and I2 were 0.095 ± 0.096 and 0.123 ± 0.114 mm in MA30BA and MA60BM, respectively. The error between I1 and I2 was within ± 0.17 and ± 0.33 mm or less in 72.9 and 91.5% of MA30BA and in 82.7 and 96.2% of MA60BM. In contrast, the error between I2 and I1 when calculated using the SRK/T formula was much larger – in excess of ± 0.33 mm in 38.7% of the eyes. Conclusions: L1 + L2 changes little with aging and is considered a useful marker of the position of the crystalline lens in situ. There was a high correlation between I1 and L1 + L2. These allow a far more accurate prediction of I1 than previous methods. In combination with the conventional regression formula and ray tracing, a highly accurate IOL power calculation can be attained.

PSS4 - Efficacy And Safety of Surgical Treatment Options for Primary Angle Closure Glaucoma: a Meta-Analysis of Randomised Controlled Trials

To evaluate the changes of the anterior chamber depth (ACD) and the related factors after cataract surgery with IOL implantation in order to achieve the intended postoperative refraction. Preoperative and postoperative ACD were examined in 117 patients (177 eyes) who underwent cataract surgery (phacoemulsification and posterior chamber IOL implantation). Correlations between changes of ACD and the axial lengths of the eyes, K-readings and IOL A-constants were assessed. Patients were followed-up for 3 to 24 months. (1) There was significant difference between preoperative ACD (3.19 +/- 0.39) mm and postoperative ACD (4.22 +/- 0.65) mm (P = 0.000). (2) The mean postoperative ACD change was (1.03 +/- 0.61) mm. The correlations between the ACD changes and the axial lengths of the eye and K-readings were statistically significant. (r = 0.866, r = 0.946, P = 0.001). (3) There was significant difference between preoperative ACD and postoperative ACD in the three different A-constants groups (118.9, 118.0 and 118.4) (P = 0.004, 0.001 and 0.001). There was significant difference between ACD changes in patients with A-constant 118.9 and that of 118.0 or 118.4 (P = 0.007, P = 0.01). There was no significant difference between ACD changes in patients with A-constant 118.0 and that of 118.4 (P = 0.957). Cataract surgery deepened anterior chambers at varying degrees, depending on the axial lengths of the eye, K-readings and the IOL A-constants. ACD changes and relevant factors should be considered in studying the accuracy of IOL refraction formula and in adjusting the calculated data.

PURPOSE:To evaluate the intraocular lens (IOL) subluxation after cataract surgery in patients with zonular weakness.METHODS:This study assessed the medical records of cataract patients with zonular weakness treated at Naresuan University Hospital, Thailand-country between November 2014 and October 2019. Preoperative and postoperative values of uncorrected visual acuity (UCVA), refractive error, corneal refractive power (k-value), axial length, and anterior chamber depth (ACD) were examined and compared. The refractive power was converted to spherical equivalent (SE). During the operation, grading of the zonular weakness was evaluated by the surgeon. The IOLs and the capsular tension rings were then inserted. The estimated error (EE) was considered as the difference between the theoretical IOL lens position (effective lens position [ELP]) and the clinical postoperative IOL position (postoperative ACD).RESULTS:This study included nine participants (nine eyes) with an average age of 64.7 ± 11.42 years. The median preoperative and postoperative UCVA were 1.39 (0.94–1.82) and 0.00 (0.00–0.37) logMAR, respectively. All of the participants achieved a better postoperative UCVA than preoperative UCVA. The preoperative SE was not able to be measured using an automated refractometer. The postoperative SE of all participants had improved compared with the preoperative SE. The median preoperative and postoperative ACD were 3.15 (2.59–3.48) and 3.98 (2.93–4.33) mm, respectively. The value of postoperative ACD was significantly increased from preoperative ACD. For a subluxation of IOL position, there was a statistically significant difference between the values of ELP and postoperative ACD (P = 0.008). The mean EE was 0.96 ± 0.65 mm. The EE was a positive value in all participants, and the IOL position after cataract surgery was shifted to the front.CONCLUSION:After cataract surgery, the UCVA of all participants was improved, and the postoperative ACD was statistically significantly smaller than ELP. The EE was positive, and the IOL position after cataract surgery was shifted to the front of the eye.

To calculate the necessary pseudophakic intraocular lens (IOL) power to approximate emmetropia in adult tigers. 17 clinically normal adult tigers. 33 eyes of 17 clinically normal adult tigers underwent routine ophthalmic examination and B-scan ultrasonography while anesthetized for unrelated procedures. Specific ultrasound data (globe measurements and corneal curvature) and estimated postoperative IOL positions were utilized to calculate predicted IOL power by use of Retzlaff and Binkhorst theoretical formulas. Applanation tonometry and refraction were also performed. Mean ± SD axial globe length was 29.36 ± 0.82 mm, preoperative anterior chamber depth was 7.00 ± 0.74 mm, and crystalline lens thickness was 8.72 ± 0.56 mm. Mean net refractive error (n = 33 eyes) was +0.27 ± 0.30 diopters (D). By use of the Retzlaff formula, mean predicted IOL power for the postoperative anterior chamber depth (PACD), PACD - 2 mm, and PACD + 2 mm was 43.72 ± 4.84 D, 37.62 ± 4.19 D, and 51.57 ± 5.72 D, respectively. By use of the Binkhorst equation, these values were 45.11 ± 4.91 D, 38.84 ± 4.25 D, and 53.18 ± 5.81 D, respectively. Mean intraocular pressure for all eyes was 14.7 ± 2.69 mm Hg. The calculated tiger IOL was lower than reported values for adult domestic felids. Further studies evaluating actual PACD and pseudophakic refraction would help determine the appropriate IOL power to achieve emmetropia in this species.

AimsTo assess whether incorporating a machine learning (ML) method for accurate prediction of postoperative anterior chamber depth (ACD) improves cataract surgery refraction prediction performance of a commonly used ray tracing...

Background Pentacam anterior segment analysis system(Pentacam) is more accurate in the quantitative evaluation of ocular anterior segment in primary angle-closure glaucoma (PACG) eyes than slit lamp microscope and ultrasound biomicroscope (UBM). However, its accuracy in the earlier stage of PACG before and after YAG laser peripheral iridotomy (LPI) is not fully elucidated. Objective This study was to assess the effect of YAG LPI in PACG patients with Pentacam. Methods A prospective self-controlled study was performed.Thirty-five fellow eyes (pre-clinical stage of PACG) of acute PACG and 35 fellow eyes of chronic PACG were included in the Second Hospital of Hebei Medical University from July, 2012 to December, 2013.YAG LPI was performed on the eyes, and the parameters of ocular anterior segment including central anterior chamber depth (ACD), anterior chamber volume (ACV) and peripheral anterior chamber angle (ACA) were measured and compared by Pentacam before and 1 day, 7 days, 28 days after operation.This study was approved by the Ethic Committee of the Second Hospital of Hebei Medical University and informed consent was obtained from all subjects. Results In pre-clinical stage of PACG eyes, the postoperative ACD and ACV values were increased in comparison with preoperation, showing significant differences among various time points (ACD: F=6.783, P=0.004; ACV: F=19.090, P=0.000), and no significant difference was found in ACA among different time points (F=0.153, P=0.928). In the fellow eyes of chronic PACG, the postoperative ACD and ACV values were larger than those of preoperation, with significant differences among various time points (ACD: F=21.576, P=0.000; ACV: F=47.506, P=0.000), and no significant difference was found in ACA among different time points (F=0.581, P=0.629). The change values of ACD and ACV were (0.064±0.022)mm and (27.840±4.963)mm3 in the eyes of pre-clinical stage of PACG, and those in the fellow eyes of chronic PACG were (0.047±0.020)mm and (21.000±3.278)mm3, showing significant differences between the two groups (ACD: t=2.783, P=0.008; ACV: t=5.749, P=0.000). Conclusions Pentacam allows easy, fast, automatic and non-contact quantification and three-dimension image of the anterior chamber parameters before and after YAG LPI in pre-clinical stage of PACG eyes and fellow eyes of chronic PACG.The ACD deepens and ACV increases after LPI in glaucomous eyes, especially in the pre-clinical stage of PACG eyes. Key words: Glaucoma, angle-closure/surgery; Anterior chamber/pathology; Biometry; Imaging, three-dimensional; Diagnostic techniques, ophthalmological/instrumentation; Laser therapy; Iridectomy; Pentacam anterior segment analysis system

To determine appropriate intraocular lens (IOL) implant strength to approximate emmetropia in horses. 16 enucleated globes and 4 adult horses. Lens diameter of 10 enucleated globes was measured. Results were used to determine the appropriate-sized IOL implant for insertion in 6 enucleated globes and 4 eyes of adult horses. Streak retinoscopy and ocular ultrasonography were performed before and after insertion of 30-diopter (D) IOL implants (enucleated globes) and insertion of 25-D IOL implants (adult horses). In enucleated globes, mean +/- SD lens diameter was 20.14 +/- 0.75 mm. Preoperative and postoperative refractive state of enucleated globes with 30-D IOL implants was -0.46 +/- 1.03 D and -2.47 +/- 1.03 D, respectively; preoperative and postoperative difference in refraction was 2.96 +/- 0.84 D. Preoperative anterior chamber (AC) depth, crystalline lens thickness (CLT), and axial globe length (AxL) were 712 +/- 0.82 mm, 11.32 +/- 0.81 mm, and 40.52 +/- 1.26 mm, respectively; postoperative AC depth was 10.76 +/- 1.16 mm. Mean ratio of preoperative to postoperative AC depth was 0.68. In eyes receiving 25-D IOL implants, preoperative and postoperative mean refractive error was 0.08 +/- 0.68 D and -3.94 +/- 1.88 D, respectively. Preoperative AC depth, CLT, and AxL were 6.36 +/- 0.22 mm, 10.92 +/- 1.92 mm, and 38.64 +/- 2.59 mm, respectively. Postoperative AC depth was 8.99 +/- 1.68 mm. Mean ratio of preoperative to postoperative AC depth was 0.73. Insertion of 30-D (enucleated globes) and 25-D IOL implants (adult horses) resulted in overcorrection of refractive error.

The surgical risk and complication rate after cataract surgery are extremely high in patients with nanophthalmos. This study is designed to compare the visual and refractive outcomes before and after coaxial micro-incision phacoemulsification and evaluate postoperative complications. Fifty nine patients (89 eyes) with axial length (AL) < 21 mm diagnosed with nanophthalmos were enrolled in this retrospective study. All patients underwent coaxial micro-incision phacoemulsification and IOL implantation. The main outcome measures included anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (A CA), intraocular pressure (IOP) and best corrected visual acuity (BCVA). Wilcoxon signed rank test or Mann-Whitney test, and Chi-square test and logistic regression analysis were performed for statistical tests as appropriate. The median AL was 19.63 mm. Sixty-six eyes (74.16%) had a history of surgical intervention. Postoperative ACD, ACV and ACA were increased significantly (all P < 0.001), whereas postoperative IOP was decreased significantly (P < 0.001) after surgery. Previous surgical intervention was related to a reduction in the postoperative ACD and ACA (P < 0.01), and both preoperative and postoperative IOP (P < 0.001). Postoperative BCVA was improved in 94.38% of the cases. Intraoperative complications mainly included iridoschisis (6 eyes, 6.74%). Early postoperative complications included temporary corneal edema (TCE) (23 eyes, 25.84%), anterior inflammatory response (AIR) (19 eyes, 21.35%), cystoid macular edema (CME) (14 eyes, 15.73%), and uveal effusion (4 eyes, 4.49%). Late postoperative complications included CME (8 eyes, 8.99%), uveal effusion (8 eyes, 8.99%), malignant glaucoma (2 eyes, 2.25%) and posterior capsular opacification (PCO) (10 eyes, 11.24%). The majority of complications (80%) were successfully resolved by pharmacotherapy or operation. The risk of surgical complications was greater in patients with lower AL, ACD, ACV or ACA and higher nuclear hardness or mean keratometry (Km). With reasonable preoperative management, prudent selection of the lens, rigorous surgical technique and unerring cognition of potential complications, coaxial microincision phacoemulsification lens surgery can be performed in patients with nanophthalmos and yield favorable outcomes and a low incidence of complications.

Measurement and use of postoperative anterior chamber depth of fellow eye in refractive outcomes

Background Following cataract surgery, the focus changed from relieving blindness to achieving precise refractive correction and rapid recovery. A lot of factors influence the visual outcome. The variance in postoperative anterior chamber depth (ACD) is one of the essential factors. Aim To record the differences in postoperative ACD measurements and its effects on postoperative refraction in individuals who had uneventful cataract surgery at Suez General Hospital. Patіents and methods Fifty eyes from fifty patients who underwent uneventful phacoemulsification by the same surgeon. Using the ocular biometer The IOLMaster 500 from ZEISS, (ACD) were assessed pre and postsurgery, 1 and 3 months after the procedure. The postoperative spherical equivalent were recorded. Results Mean age was (58.7±7.5) years. a highly significant difference in ACD values between preoperative and 1 and 3 months post-surgery (P&lt;0.0001). While the ACD difference between 1 and 3 months postsurgery was insignificant (P=0.332). Fourteen (28%) of the eyes had a myopic spherical refractive error, 24 (48%) had a hyperopic refractive error, and 12 (24%) had no refractive error. An inverse association (r=–0.243, P=0.039) between the myopic sphere refractive errors and the variation in ACD. Conclusіon A high incidence of postoperative hyperopic shift spherical errors was linked to more extensive preoperative ACD measurements associated with less ACD deepening. While a more significant incidence of postoperative myopic shift spherical errors was linked to a small preoperative ACD with a greater degree of postoperative ACD deepening; therefore, postoperative ACD changes have a significant impact on postoperative refraction.

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.

Use of the Crystalline Lens Equatorial Plane as a New Parameter for Predicting Postoperative Intraocular Lens Position