Effect of Lens Vault on the Accuracy of Intraocular Lens Calculation Formulas in Shallow Anterior Chamber Eyes

Automated expert-level scleral spur detection and quantitative biometric analysis on the ANTERION anterior segment OCT system

AIM

To perform an independent validation of deep learning (DL) algorithms for automated scleral spur detection and measurement of scleral spur-based biometric parameters in anterior segment optical coherence tomography (AS-OCT) images.

METHODS

Patients receiving routine eye care underwent AS-OCT imaging using the ANTERION OCT system (Heidelberg Engineering, Heidelberg, Germany). Scleral spur locations were marked by three human graders (reference, expert and novice) and predicted using DL algorithms developed by Heidelberg Engineering that prioritise a false positive rate <4% (FPR4) or true positive rate >95% (TPR95). Performance of human graders and DL algorithms were evaluated based on agreement of scleral spur locations and biometric measurements with the reference grader.

RESULTS

1308 AS-OCT images were obtained from 117 participants. Median differences in scleral spur locations from reference locations were significantly smaller (p<0.001) for the FPR4 (52.6±48.6 µm) and TPR95 (55.5±50.6 µm) algorithms compared with the expert (61.1±65.7 µm) and novice (79.4±74.9 µm) graders. Intergrader reproducibility of biometric measurements was excellent overall for all four (intraclass correlation coefficient range 0.918-0.997). Intergrader reproducibility of the expert grader (0.567-0.965) and DL algorithms (0.746-0.979) exceeded that of the novice grader (0.146-0.929) for images with narrow angles defined by OCT measurement of angle opening distance 500 µm anterior to the scleral spur (AOD500)<150 µm.

CONCLUSIONS

DL algorithms on the ANTERION approximate expert-level measurement of scleral spur-based biometric parameters in an independent patient population. These algorithms could enhance clinical utility of AS-OCT imaging, especially for evaluating patients with angle closure and performing intraocular lens calculations.

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.

Intraocular lens power calculation in eyes with a shallow anterior chamber depth and normal axial length

We compared the accuracy of three intraocular lens (IOL) calculation formulas in eyes with a shallow anterior chamber depth (ACD) and normal axial length (AXL) and control eyes. We retrospectively reviewed eyes with a shallow ACD (<2.5 mm from the corneal epithelium) with normal AXL (22.5≤AXL<24.0 mm) and controls (3.0≤ACD<3.5 mm and normal AXL). Prediction error (PE) and median absolute error (MedAE) were evaluated with SRK/T, Barrett Universal II (BUII), and Kane formulas after adjusting the mean PE to zero for all patients. Percentages of eyes achieving a PE within 0.25 to 1.00 D, and correlations between ACD, lens thickness (LT), and PE were analyzed. Thirty-five shallow ACD and 63 control eyes were included. PE in the shallow ACD group showed more hyperopic results with BUII and Kane but not with SRK/T compared to controls. Within the shallow ACD group, PE showed more hyperopic results in BUII and Kane compared to SRK/T. However, the standard deviation (SD) of PE among formulas was not different. In the shallow ACD group, SRK/T showed a higher percentage of PE within 0.25 D than BUII and Kane, but the percentages within 0.50 to 1.00 D were similar. PE was negatively correlated with ACD in BUII and Kane, and positively correlated with LT in all formulas. BUII and Kane may induce slight hyperopic shift in eyes with a shallow ACD and normal AXL. However, the performance of the three formulas was comparable in the shallow ACD group in terms of MedAE, the SD of PE, and the percentage of eyes achieving PE within 0.50 D.

Prediction of postoperative effective lens position using iris root depth in primary angle-closure diseases

PURPOSE

To evaluate the role of a new parameter, iris root depth (IRD), in intraocular lens power calculation using ultrasound biomicroscopy (UBM) in primary angle-closure diseases (PACDs), and to compare the accuracy of 6 formulas in PACDs: Barrett Universal II (BUII), Haigis, Hill-Radial Basis Function (RBF) v. 3.0, Hoffer Q, Kane and Sanders Retzlaff Kraff/Theoretical (SRK)/T.

SETTING

Zhongshan Ophthalmic Center, Guangzhou, China.

DESIGN

Retrospective consecutive case series.

METHODS

Patients diagnosed with PACDs who had undergone cataract surgery were reviewed to first evaluate the performance of 6 formulas. Then preoperative UBM examinations of 58 eyes were used to measure IRD and predict effective lens position (ELP) to generate the Haigis IRD formula. The accuracy of Haigis IRD was compared with BUII, Haigis and Kane formulas. The SD of predicted error was the main indicator evaluating formula performance, according to heteroscedastic analysis.

RESULTS

103 eyes (103 patients) were included. The SDs of Kane (0.59, P = .01), RBF 3.0 (0.61, P = .02) and SRK/T formula (0.62, P = .04) were significantly lower than Hoffer Q. Modified with IRD, Haigis IRD generated the lowest SD (0.41), which was significantly lower than Haigis formula (0.54, P = .03) and was equal to Kane formula (0.45, P = .37).

CONCLUSIONS

Kane, RBF 3.0 and SRK/T were more accurate in PACD eyes. Optimized with IRD, Haigis IRD formula achieved the lowest SD and had comparable accuracy with Kane formula. IRD could be a promising parameter to improve accuracy of IOL power calculation for PACDs.

A Comparative Study on the Accuracy of IOL Calculation Formulas in Nanophthalmos and Relative Anterior Microphthalmos

PURPOSE

We sought to compare the prediction accuracy of 6 intraocular lens (IOL) formulas, namely, the Haigis, Hoffer Q, Holladay I, SRK/T, Barrett Universal II and Hoffer QST formulas, in microphthalmic eyes, including those with nanophthalmos and relative anterior microphthalmos (RAM).

DESIGN

Retrospective case series.

METHODS

Twenty-six eyes with nanophthalmos (axial length [AL] 16.84 ± 1.36 mm, range 15.25 mm-19.82 mm) and 12 eyes with RAM (corneal diameter 8.41 ± 0.92 mm, range 7.00 mm-9.50 mm) receiving cataract surgery were included. The IOL Master 500 was used for biometry; thus, lens thickness (LT) was omitted in the IOL power calculation. The mean and median arithmetic and absolute prediction errors (PEs) of the 6 original calculation formulas, the absolute PEs of the 6 formulas after optimization, and the proportion of PEs within ±0.25 diopters (D), ±0.5 D, ±1 D, and ±2 D with each formula were compared. The factors influencing PE were analyzed by multivariate regression.

RESULTS

In the nanophthalmos group, the overall prediction results were shifted to myopia. The original Haigis formula had the smallest median absolute PE (1.61 D, P < 0.001), and the optimized Haigis formula had the highest proportion of PEs within ±0.25 D, ±0.5 D, and ±1 D. In the RAM group, the overall prediction results were not significantly different from 0 (P > .05). No significant difference was found among the formulas before optimization (P = .146) and after optimization (P = .161), but the optimized Barrett Universal II formula had the highest proportion of PEs within ±1 D and ±2 D.

CONCLUSIONS

When omitting the LT parameter in the calculation, the Haigis formula was the most accurate in cataract patients with nanophthalmos (AL <20 mm) among the 6 IOL calculation formulas, and the Barrett Universal II formula had the highest accuracy in cataract patients with RAM (corneal diameter ≤9.5 mm).

A Comparative Study of Two Extended Depth of Focus Intraocular Lenses

OBJECTIVE

To assess and compare the visual performance of two extended depth-of-focus intraocular lenses (IOLs), Tecnis Symfony (Symfony; Johnson & Johnson Vision, Santa Ana, CA) and Acrysof IQ Vivity (Vivity; Alcon Inc, Fort Worth, TX).

METHODS

The medical records of patients undergoing cataract surgery with Symfony or Vivity implantation from May 2021 to September 2021 and the data available for the 3-month follow-up were reviewed. The main measures of the findings were uncorrected and corrected distance (4 m) visual acuity (VA), uncorrected intermediate (66 cm) VA (UIVA) and uncorrected near (40 and 33 cm) VA (UNVA), refractive error (RE), defocus profiles analysis, optical quality parameters, and patient-reported quality of vision questionnaire results.

RESULTS

Of the 40 patients, 19 patients (31 eyes) were treated with the Symfony IOL and 21 (32 eyes) with the Vivity IOL. The mean age of the patients was 63.4±7.8 (range, 40-76) years in the Symfony group and 61.8±9.7 (range, 40-77) years in the Vivity group. There was no meaningful difference between the two groups in the preoperative parameters, except that the Vivity group had a better CDVA. Among the main measures of results, there was no statistically significant difference, except for the UNVA (33 cm). The Symfony group also showed a smoother defocus curve at 3 months postoperatively.

CONCLUSION

There was no significant difference between the two groups regarding uncorrected/corrected distance VA, UIVA, UNVA (40 cm), RE, optical quality parameters, and patient-reported quality of vision questionnaire results. The Symfony group demonstrated a significantly superior UNVA (33 cm) and a smoother defocus curve with a broad landing zone.

Comparison of Formula-Specific Factors and Artificial Intelligence Formulas with Axial Length Adjustments in Bilateral Cataract Patients with Long Axial Length

Introduction

To evaluate and compare the effectiveness for reducing the prediction error (PE) of the second eye using formula-specific factors, artificial intelligence (AI) formulas (PEARL-DGS and Kane), and the Cooke-modified axial length (CMAL) methods in bilateral cataract patients with long axial length (AL).

Methods

A total of 98 patients with long AL who underwent sequential bilateral cataract surgeries were retrospectively enrolled. The second-eye IOL power was calculated by the formula-specific factors, AI formulas, and CMAL methods when the first eye suffered from refraction surprise. The correction factors of eight formulas were calculated by regression analysis.

Results

There was a significant correlation between bilateral preoperative biometric parameters (P < 0.05) as well as bilateral PE (P < 0.05). The Kane formula displayed the lowest median absolute error (MedAE) and highest proportion of PE within ± 0.50 and ± 1.00 D compared with other formulas for the first eye. For the second-eye refinement, all three methods could reduce the second-eye MedAE. The formula-specific correction factors were 0.250, 0.331, 0.343, 0.394, 0.409, 0.452, 0.503, and 0.520 for Kane, Barrett Universal II (BUII), PEARL-DGS, Holladay 2, Holladay 1, Haigis, Hoffer Q, and SRK/T, respectively. The new AI-based Kane and PEARL-DGS with or without the CMAL methods could improve the refractive outcomes of the second eye in sequential bilateral cataract patients with long AL. The Kane, BUII, and PEARL-DGS with specific correction factors displayed higher accuracy compared with the other two methods (P < 0.05).

Conclusions

The new AI-based Kane and PEARL-DGS with or without the CMAL methods could improve the refractive outcomes of the second eye in sequential bilateral cataract patients with long AL. Notably, the Kane, PEARL-DGS, and BUII with specific correction factors displayed higher accuracy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40123-022-00551-6.

Efficacy of the Image-Guided Alignment System for a Four-Haptic Hydrophobic Monofocal Toric Intraocular Lens

OBJECTIVE

To compare the difference in performance between the image-guided alignment system and the manual-marking method in the four-haptic hydrophobic monofocal toric intraocular lens (IOL).

METHODS

Medical records of patients who underwent cataract surgery with a four-haptic hydrophobic monofocal toric IOL implantation between May 2020 and April 2021 and with 3-month visit data available were investigated. Toric IOL misalignment, residual astigmatism, and mean prediction errors between the two groups were compared.

RESULTS

This study included 49 eyes of 44 patients (women: 68%; mean age: 67.2±7.0 [range: 47-82] years). Twenty-nine eyes of 26 patients were treated with toric IOL implantation using the image-guided system and 20 eyes of 18 patients were treated using the manual-marking method. No statistical differences were observed regarding the baseline characteristics of the two groups. Three months after the surgery, the misalignment of the toric IOL was significantly lower in the image-guided group (2.18°±0.65°, range: 1.26°-3.95°) than in the manual; marking group (4.72°±0.74°, range: 3.44°-6.21°; P<0.001).

CONCLUSION

In comparison to the manual-marking method, the image-guided system reduced the misalignment of a four-haptic hydrophobic monofocal toric IOL.

Comparison of visual results and optical quality of two presbyopia-correcting intraocular lenses: TECNIS symfony versus TECNIS synergy

PURPOSE

This study compared the extended depth of focus (EDOF) intraocular lens (IOL) (ZXR00; Tecnis® Symfony^®, Johnson & Johnson Vision, Santa Ana, CA, USA) and a new presbyopia-correcting IOL that combines EDOF and multifocal profiles (ZFR00; Tecnis^® Synergy^®, Johnson & Johnson Vision, Santa Ana, CA, USA) with the same material.

METHODS

The medical records of patients undergoing cataract surgery with ZXR00 or ZFR00 implantation between March 2021 and July 2021 and with the data available for the 3-month visit were reviewed. The uncorrected near, intermediate, and distance visual acuity (VA), corrected distance VA, defocus curves, refractive errors (RE), optical quality parameters, and patient-reported visual performance parameters were the main outcome measures.

RESULTS

Among the twenty-three enrolled patients, twelve patients (21 eyes) received ZXR00 and nine patients (17 eyes) received ZFR00. The mean age of the patients was 59.6 ± 10.6 (range: 49 to 70) and 65.2 ± 8.2 (range: 45 to 82) years in ZXR00 and ZFR00 groups, respectively, without significant difference. There was not a significant difference between the two groups in terms of baseline parameters and postoperative RE. The ZFR00 group showed markedly superior intermediate and near VA (p < 0.001 for all) at 3 months postoperatively. In terms of optical quality, ZXR00 was significantly better than ZFR00 (p < 0.001).

CONCLUSIONS

Both IOLs had comparable distance VA. ZFR00 IOL was superior for intermediate and near visual acuity, but ZXR00 IOL was better for optical quality. Research with more participants is needed to support this finding.