Changes in Anterior Chamber Depth after Phacoemulsification in Pseudoexfoliative Eyes and their Effect on Accuracy of Intraocular Lens Power Calculation

Accuracy of intra ocular lens calculation formulae in patients with pseudoexfoliation syndrome

BACKGROUND

The purpose of this study was to investigate the visual and refractive outcomes in patients with pseudoexfoliation (PXF) undergoing routine cataract surgery and to compare the accuracy of intraocular lens (IOL) power calculation formulae.

METHODS

Retrospective case-series study from Shamir medical center, a public hospital, Israel. Medical records of patients who underwent routine cataract surgery between January 2019 and August 2021 were investigated. Postoperative visual acuity and manifest refraction were examined. The error in predicted refraction and IOL power calculation accuracy within a range of ± 0.50 to ± 1.00 diopters were compared between different IOL calculating formulae.

RESULTS

151 eyes of 151 patients ages 73.9 ± 7.1 years were included in this study- 58 eyes in the PXF group and 93 eyes in the control group. The mean absolute error (MAE) for the BUII formula was 0.63D ± 0.87 for the PXF group and 0.36D ± 0.48 for the control group (p < 0.05). The MAE for the Hill-RBF 3.0 formula was 0.61D ± 0.84 for the PXF group and 0.42D ± 0.55 for the control group (p = 0.05). There were significant differences in MAE and MedAE between PXF group and control group measures (p < 0.05). In the PXF group there were no significant differences between the different formulae.

CONCLUSIONS

There were significant differences in accuracy of IOL power calculations in all formulae between PXF group and control group measures. PXF patients show hyperopic shift from predicted refraction. Barret universal II formula had the highest proportion of eyes with absolute error in prediction below or equal to 0.50 D in both PXF and control groups.

Medium-term visual and refractive outcomes in patients with pseudoexfoliation implanted with a toric or multifocal intraocular lens

PURPOSE

To report medium-term visual acuity and refractive outcomes of patients with pseudoexfoliation implanted with toric or multifocal intraocular lenses (IOLs).

METHODS

We retrospectively reviewed patients with pseudoexfoliation who had undergone phacoemulsification between 2016 and 2020 with at least 24 months follow-up.

RESULTS

Mean follow-up was 44.17 ± 14.95 months. Toric IOLs were implanted in 48 eyes: mean uncorrected LogMAR visual acuity one month after surgery was 0.03 ± 0.09, decreasing to 0.08 ± 0.11 at the last visit (p = .01). Mean refractive cylinder was -0.12 ± 0.36 diopters one month after surgery and -0.25 ± 0.44 diopters at the last follow-up visit, p = .012. Multifocal IOLs were implanted in 42 patients: binocular uncorrected distance visual acuity was -0.02 ± 0.04 one month after surgery and 0.01 ± 0.05 at the last visit (p = .004); near acuity was 0.01 ± 0.03 and 0.04 ± 0.06 respectively (p = .001). In eyes with pseudoexfoliation, absolute spherical equivalent prediction error was 0.22 ± 0.20 diopters for toric and 0.21 ± 0.19 diopters for multifocal IOLs. One month after surgery 68.6% of eyes with toric IOLs and 74.2% of eyes with multifocal IOLs were within ±0.25 diopters of target spherical equivalent and 91.6% and 90.5% were within ±0.5 diopters, respectively. Spherical equivalent did not change significantly during follow-up for either group.

CONCLUSION

Prediction error in eyes with pseudoexfoliation implanted with toric or multifocal IOLs was low and similar to values reported for normal eyes. Postoperative refractive cylinder with toric IOLs was low, with little change during follow-up. Visual function in patients receiving multifocal IOLs was excellent. Therefore, the implantation of these IOLs in eyes with pseudoexfoliation does not seem to cause medium-term problems.

Evaluation of changes of anterior segment parameters in patients with pseudoexfoliation syndrome after cataract surgery using anterior segment optical coherence tomography

The aim of the study was to compare the anterior segment parameters after cataract surgery in pseudoexfoliation syndrome (PEX) and control eyes. We conducted a prospective comparative study of 36 eyes (PEX group), 16 eyes (PEXG group) and 46 eyes (control group) of 98 patients after phacoemulsification with intraocular lens implantation. Before surgery, 1 week, 1 month and 3 months postoperatively, anterior chamber parameters were evaluated by swept source anterior segment optical coherence tomography (AS-OCT). Anterior chamber depth (ACD), angle opening distance (AOD500/750), trabecular-iris space area (TISA500/750), trabecular-iris angle (TIA500/750) and lens vault (LV) were assessed at each study visit. Preoperatively, ACD, AOD500/750 and TISA500/750 were significantly smaller, while LV was significantly greater in PEX and PEXG eyes than in controls. 3 months postoperatively all irido-corneal parameters and ACD were significantly greater in all study groups without intergroup differences. ACD and LV significantly increased in PEX group between 1 and 3 months after surgery while being stable in control group. Relative increases in ACD, AOD500, TISA750, TIA500/750 were significantly higher in PEX and PEXG groups than in controls. Our study finds that ACD and iridocorneal parameters in AS-OCT demonstrated significantly greater relative increases 3 months after phacoemulsification in PEX and PEXG groups than in control eyes. Significantly greater deepening of anterior chamber and opening of the irido-corneal angle may be a reason for different refractive outcomes and IOP control in patients with PEX and PEXG after routine cataract surgery.

The effect of uneventful cataract surgery on Schlemm's canal and the trabecular meshwork in cases with pseudoexfoliation

PURPOSE

To evaluate the effect of uneventful cataract surgery on Schlemm's canal (SC) and the trabecular meshwork (TM) in cases with pseudoexfoliation (PX).

METHODS

In this prospective study, 37 PX and 37 normal eyes, who underwent cataract surgery, were included. The PX group was further divided into two subgroups: PX syndrome (PXS) and PX glaucoma (PXG). Preoperative complete ophthalmologic examination, anterior segment (AS) imaging using a Scheimpflug camera, and measurements of SC length and area and TM thickness and length using AS optical coherence tomography (AS-OCT) were performed in all cases. All measurements were repeated at the first and third months after surgery.

RESULTS

Preoperative intraocular pressure (IOP), AS parameters, SC, and TM values showed no significant differences between the groups (p > 0.05). After surgery, there was a significant increase in AS parameter values and a significant decrease in IOP values in both the PX and control groups (p < 0.05). The nasal and temporal SC area showed a significant increase in the PX group after surgery (p = 0.007, p = 0.003, respectively). In the subgroup analysis, the only significant change in the nasal and temporal SC area was in the PXS group (p = 0.006, p = 0.003, respectively).

CONCLUSION

Cataract surgery resulted in an increase in the SC area in patients with PXS. This increase may be due to multiple mechanisms including the IOP-lowering effect of cataract removal, change in AS, and removal of intraocular PX material after surgery.

Pseudoexfoliation Glaucoma as a Predictor of Refractive Surprise After Uneventful Cataract Surgery

PRCIS

The pseudoexfoliation glaucoma group produced higher mean absolute error (MAE) and higher percentages of large-magnitude prediction error, in all investigated intraocular lens formulas. Postoperative anterior chamber angle and change in intraocular pressure (IOP) were associated with absolute error.

PURPOSE

The purpose of this study is to evaluate refractive outcomes of cataract surgery in patients with pseudoexfoliation glaucoma (PXG) and to determine the predictive factors for refractive errors.

MATERIALS AND METHODS

Fifty-four eyes with PXG, 33 eyes with primary open angle glaucoma (POAG) and 58 normal eyes undergoing phacoemulsification, in Haydarpasa Numune Training and Research Hospital, Istanbul, Turkey, were included in this prospective study. The follow-up was 3 months. Preoperative and postoperative anterior segment parameters measured by Scheimpflug camera were compared after adjusting for age, sex, and axial length. The mean prediction error, MAE, and percentages of large-magnitude prediction error (>±1.0 D) in SRK/T, Barrett Universal II, and Hill-RBF formulas were compared.

RESULTS

There was a significantly greater anterior chamber angle (ACA) enlargement in PXG eyes compared with POAG ( P =0.006) and normals ( P =0.04). The PXG group showed significantly higher MAE in SRK/T, Barrett Universal II, and Hill-RBF (0.72, 0.79, and 0.79 D, respectively) than POAG (0.43, 0.25, and 0.31 D, respectively) and normals (0.34, 0.36, 0.31 D, respectively) ( P <0.0001). The large-magnitude error was significantly more frequent in the PXG group among the 3 groups with SRK/T (37%, 18%, and 12%, respectively) ( P =0.005), Barrett Universal II (32%, 9%, and 10%, respectively) ( P =0.005), and Hill-RBF (32%, 9%, and 9%, respectively) ( P =0.002). The MAE was correlated with postoperative ACA and IOP decrease in Barrett Universal II ( P =0.02 and 0.007, respectively) and Hill-RBF ( P =0.03 and 0.02, respectively).

CONCLUSIONS

PXG may be a predictor for refractive surprise after cataract surgery. Prediction errors may be due to IOP-lowering effect of surgery and larger postoperative ACA than expected, in the presence of zonular weakness.

Surgeon effects on cataract refractive outcomes are minimal compared with patient comorbidity and gender: an analysis of 490 987 cases

AIM

To investigate effect of patient age, gender, comorbidities and surgeon on refractive outcomes following cataract surgery.

METHODS

Study population: patients on UK national ophthalmic cataract database on cataract operations undertaken between 1 April 2010 and 31 August 2018. Variables examined included gender, age, diabetic retinopathy, glaucoma, high myopia, inherited retinal disease, optic nerve disease, uveitis, pseudoexfoliation, vitreous opacities, retinal pathology, cataract type, previous surgery and posterior capsular rupture. A multivariate normal cross-classified model was fitted to the refractive outcome using Markov Chain Monte Carlo (MCMC) methods with diffuse priors to approximate maximum likelihood estimation. A MCMC chain was generated with a burn-in of 5000 iterations and a monitoring chain of 50 000 iterations.

RESULTS

490 987 cataract operations were performed on 351 864 patients by 2567 surgeons. Myopic and astigmatic errors were associated with posterior capsule rupture (-0.38/+0.04×72), glaucoma (-0.10/+0.05×95), previous vitrectomy (-0.049/+0.03×66) and high myopia (-0.07/+0.03×57). Hyperopic and astigmatic errors were associated with diabetic retinopathy (+0.08/+0.03×104), pseudoexfoliation (+0.07/+0.01×158), male gender (+0.12/+0.05×91) and age (-0.01/+0.06×97 per increasing decade). Inherited retinal disease, optic nerve disease, previous trabeculectomy, uveitis, brunescent/white cataract had no significant impact on the error of the refractive outcome. The effect of patient gender and comorbidity was additive. Surgeons only accounted for 4% of the unexplained variance in refractive outcome.

CONCLUSION

Patient comorbidities and gender account for small but statistically significant differences in refractive outcome, which are additive. Surgeon effects are very small.

Refractive Outcomes of Uneventful Cataract Surgery in Pseudoexfoliation Syndrome and Pseudoexfoliation Glaucoma

Purpose

To compare the refractive outcomes after cataract surgery between patients with and without pseudoexfoliation, and to evaluate the risk factors of refractive error.

Methods

Retrospective review of 210 eyes with pseudoexfoliation (study group) and 510 normal eyes (control group) that underwent uneventful phacoemulsification with intraocular lens implantation. The study group included pseudoexfoliation syndrome and pseudoexfoliation glaucoma (PXG) subgroups. The main outcome measure was refractive error, defined as the difference between the target refraction and postoperative refraction in diopter (D). A refractive error >±1.0 D was identified as a large-magnitude refractive error. The frequency of the large-magnitude refractive error was compared between study and control groups, and also between each subgroup and normal eyes. The factors influencing refractive error were analyzed by logistic regression.

Results

There was a significantly higher frequency of a refractive error >± 1.0 D and hyperopic error >1.0 D in the study group than in the control group (p = 0.001 and p = 0.003, respectively). In the multivariate logistic regression analysis, PXG and poor preoperative visual acuity were related with a large-magnitude refractive error (p = 0.001 and p = 0.02, respectively) Refractive error >± 1.0 D and hyperopic error >1.0 D were noted more often in PXG eyes that had an intraocular pressure spike >25 mmHg at postoperative first 24 hours (p = 0.01 and p=0.03, respectively).

Conclusions

The eyes with pseudoexfoliation were at a high risk for refractive error, especially in the presence of glaucoma. In PXG, the only significant risk factor for refractive error was observed to be the presence of an intraocular pressure spike.

Intraocular lens power calculations in eyes with pseudoexfoliation syndrome

To compare refractive outcomes after cataract surgery in pseudoexfoliation syndrome (PEX) and control eyes and to investigate the accuracy of 3 intraocular lens (IOL) calculation formulas in these eyes. In this prospective comparative study 42 eyes (PEX group) and 38 eyes (control group) of 80 patients were included. The follow-up was 3 months. The refractive prediction error (RPE), mean absolute error (MAE), median absolute error (MedAE) and the percentages of eyes within ± 0.25 D, ± 0.5 D, ± 1.0 D and ± 2.0 D of prediction error were calculated. Three IOL calculation formulas (SRK/T, Barrett Universal II and Hill-RBF) were evaluated. PEX produced statistically significantly higher mean absolute errors and lower percentages of eyes within ± 0.5 D than control eyes in all investigated IOL calculation formulas. There were no statistically significant differences in the median absolute errors between the 3 formulas in either PEX or control eyes. Refractive outcomes after cataract surgery are statistically significantly worse in PEX than in control eyes. All three IOL calculation formulas produced similar results in both PEX and control eyes.Trial registration: ClinicalTrials.gov registration number NCT04783909.

Anterior chamber depth measurement using Pentacam and Biograph in children

CLINICAL RELEVANCE

Accurate measurement of the anterior chamber depth is very important. There is no report regarding the agreement between rotating Scheimpflug imaging (Pentacam HR) and biograph (Lenstar LS 900) in children. This study therefore explores the agreement between Pentacam and Biograph in measuring anterior chamber depth in children.

BACKGROUND

This study aims to determine the agreement between Pentacam and Biograph in measuring anterior chamber depth in children.

METHODS

The participants were students living in urban and rural areas of Shahroud, Iran, selected through cluster sampling. The students were transported to the examination site to undergo imaging and optometric tests. Pentacam imaging was then conducted, and biograph was used to measure biometric components. In this report, the anterior chamber depth was calculated from the corneal endothelium.

RESULTS

Of 6624 students selected randomly, 5620 participated in the study. After applying the exclusion criteria, 4882 eyes were included in the final analysis. The mean anterior chamber depth measured by the Pentacam (3.09 ± 0.26 mm) was higher than that of biograph (3.04 ± 0.24 mm) (p < 0.001). The 95% limit of agreement (LOA) between the two devices was -0.19 to 0.09 mm. The variation of the difference between the two devices decreased, LOA became narrower, and the correlation coefficient of the devices increased with ageing. The highest intraclass correlation coefficient was seen among myopic (0.974) participants. The 95% LOA was -0.20 to 0.12 mm in hyperopic, -0.17 to 0.07 mm in myopic and -0.19 to 0.09 mm in emmetropic participants.

CONCLUSION

The Pentacam and Biograph can be used interchangeably for measuring the anterior chamber depth in children.

Refractive precision in uncomplicated eyes with pseudoexfoliation: three-piece versus one-piece intraocular lens implantation

PURPOSE

To evaluate the refractive precision of three-piece versus one-piece intraocular lenses (IOLs) in eyes with pseudoexfoliation (PXF) and changes in anterior chamber depth (ACD) following cataract surgery.

METHODS

This prospective, nonrandomized, interventional, comparative case series included PXF eyes, which were implanted with one-piece acrylic IOL or three-piece acrylic IOLs (Group A; n = 31, Group B; n = 30). Non-PXF control eyes were implanted with one-piece acrylic IOL (Group C; n = 30). Postoperative refractive error (RE) and absolute RE, as well as pre- to postoperative ACD changes, were statistically analysed. A p value < 0.05 was considered statistically significant.

RESULTS

Changes in ACD (mean ± standard deviation) in Groups A, B and C were 0.9 ± 0.4, 1.0 ± 0.3 and 0.7 ± 0.4 mm, respectively. Significant differences were found between Groups A and C (p = 0.043) and between Groups B and C (p = 0.008). In Groups A, B and C, the median and interquartile (Q1 to Q3) values were 0.3 (-0.8 to 1.0), -0.5 (-0.8 to -0.3) and 0.1 (-0.4 to 0.3) for RE and 1.0 (0.4 to 1.3), 0.5 (0.3 to 0.8) and 0.3 (0.3 to 0.5) for absolute RE, respectively. The RE differences between Group A and B (p = 0.009) and Group B and C (p < 0.001) were statistically significant. For absolute RE, the differences were significant for all comparisons (p < 0.05).

CONCLUSION

Refractive precision in PXF eyes may be better with three-piece than with one-piece IOL implantation, but worse than with one-piece IOL implantation in non-PXF eyes. Significant changes in ACD in PXF eyes may be related to RE.

[Optimization of intraocular lens power calculation in pseudoexfoliation syndrome]

PURPOSE

To assess the impact of pseudoexfoliation syndrome (PEX) on the accuracy of intraocular lens (IOL) power calculation.

MATERIAL AND METHODS

The study included 243 patients who underwent phacoemulsification (PE); they were divided into the control (no PEX signs, n=131) and study (signs of PEX, n=112) groups. Barrett Universal II formula was used for IOL calculation by optical biometry (IOL-Master 500). Obtained refraction (autorefractometer Topcon-8800) was compared with target refraction to assess IOL calculation accuracy 1 month after PE.

RESULTS

Patients with PEX had significantly shallower anterior chamber compared to the control group (2.86±0.43 versus 3.0±0.43 mm, p=0.003) and steeper corneal curvature (44.31±1.5 versus 43.7±2.59 D, p=0.052). There was significant difference in absolute error of IOL calculation between the groups (-0.02±0.45 versus 0.17±0.55 D for control and study groups, respectively, p=0.004). There was no difference in IOL calculation error depending on the implanted IOL models (AcrySof SA60AT and Akreos Adapt AO) in the control group. However, implantation of SA60AT in the study group showed significant difference in IOL calculation error compared with Akreos (0.3±0.57 versus 0.04±0.51 D, p=0.01). Using linear regression, optimized A-constants were suggested for these types of IOLs for patients with PEX (118.83 for SA60AT and 118.44 for Akreos).

Impact of Pseudoexfoliative Syndrome on Effective Lens Position, Anterior Chamber Depth Changes, and Visual Outcome After Cataract Surgery

Purpose

To compare the effective lens position (ELP), anterior chamber depth (ACD) changes, and visual outcomes in patients with and without pseudoexfoliation syndrome (PEX) after cataract surgery.

Design

Prospective, randomized, fellow-eye controlled clinical case series.

Methods

This prospective comparative case series enrolled 56 eyes of 56 consecutive patients with (n = 28) or without PEX (n = 28) and clinically significant cataract who underwent standard phacoemulsification and were implanted with single-piece acrylic posterior chamber intraocular lenses (IOLs). The primary outcome parameters were the ACD referring to the distance between the corneal anterior surface and the lens anterior surface, which is an indicator of the postoperative axial position of the IOL (the so-called ELP) and distance corrected visual acuity (DCVA).

Results

Before surgery, the ACD was 2.54 ± 0.42 mm in the PEX group and 2.53 ± 0.38 mm in the control group (p = 0.941). Postoperatively, the ACD was 4.29 ± 0.71 mm in the PEX group and 4.33 ± 0.72 mm in the normal group, respectively (p = 0.533). There was no significant difference in ACD changes between groups (PEX group: 1.75 ± 0.74 mm, control group: 1.81 ± 0.61 mm, p = 0.806) and DCVA pre- (p = 0.469) and postoperatively (PEX group: 0.11 ± 0.13 logMAR, control group: 0.09 ± 0.17 logMAR, p = 0.245) between groups.

Conclusion

Preoperative and postoperative ACD, as an indicator of ELP, between PEX eyes and healthy eyes after cataract surgery showed no significant difference. Phacoemulsification induced similar changes in eyes with PEX compared to healthy eyes.

Effect of capsular tension ring on refractive results in cases with pseudoexfoliation syndrome

PURPOSE

To investigate the effect of capsular tension rings (CTRs) on postoperative refractive results in patients with pseudoexfoliation (PSX) syndrome.

MATERIALS AND METHODS

Sixty-nine patients with PSX syndrome who had uncomplicated cataract surgery between March 2016 and February 2019 were reviewed retrospectively. The patients were divided into two groups. The 35 patients in Group 1 received CTRs prior to intraocular lens implantation during cataract surgery, and the 34 patients in Group 2 had cataract surgery without CTRs. Significant zonular weakness, uncontrolled glaucoma, and ocular pathologies causing low visual acuity were excluded. The preoperative and postoperative keratometry and autorefraction measurements, preoperative expected refractive values, and absolute refractive error were recorded.

RESULTS

The mean ages of patients were 73.54 ± 9.78 years in Group 1 and 72.23 ± 6.72 years in Group 2 (p = 0.521). There was no statistically significant difference between Group 1 and Group 2 in terms of expected preoperative refraction values (-0.52 ± 0.12,-0.56 ± 0.08, respectively, p = 0.118). There was a statistically significant difference in postoperative spherical equivalent values between Group 1 and Group 2 (-0.05 ± 0.97 and -0.92 ± 0.57, respectively, p < 0.01). A statistically significant difference was found between the two groups in terms of absolute refractive error (0.46 ± 0.74 in Group 1 and -0.34 ± 0.59 in Group 2 p < 0.01).

CONCLUSION

CTR implantation causes hyperopic shift, which should be taken into consideration when calculating the lens power of intraocular lens in patients with PSX syndrome.

Effect of capsular tension ring implantation on predicted refractive error after cataract surgery in patients with pseudoexfoliation syndrome

AIM

To investigate the effect of capsular tension ring (CTR) implantation on predicted refractive error after cataract surgery in patients with pseudoexfoliation (PEX) syndrome.

METHODS

This double-blind randomized clinical trial was conducted on 60 patients with PEX syndrome referring to Imam Khomeini Hospital affiliated to Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran, for undergoing cataract surgery. The study population was divided into two groups, namely CTR group (n=30) and non-CTR group (control group; n=30). The refractive error and anterior chamber depth (ACD) were measured 1wk, 1mo, and 3mo after phacoemulsification (PE) surgery.

RESULTS

The results indicated no statistically significant difference between the two groups in terms of predicted refractive error (obtained by subtracting preoperative predicted refractive error from actual postoperative refractive error) 1wk (P=0.47), 1mo (P=0.30), and 3mo (P=0.06) after the PE surgery. Regarding the CTR group, the changes of ACD was statistically significant 1 and 3mo after the PE surgery, compared to those obtained 1wk post-surgery (P=0.005).

CONCLUSION

The CTR implantation in PEX cataractous patients without zonulysis has no statistically significant effect on the predicted refraction and ACD changes after PE. The predicted refraction error has a hyperopic shift in both groups. The results reveal the unnecessary of calculating modified IOL in CTR implantation.