Factors affecting refractive outcome after cataract surgery in primary angle-closure glaucoma

Comparison of intraocular lens power calculation formulas in patients with a history of acute primary angle-closure attack

BACKGROUND

To compare the accuracy of nine intraocular lens (IOL) power calculation formulas, including three traditional formulas (SRK/T, Haigis, and Hoffer Q) and six new-generation formulas (Barrett Universal II [BUII], Hill-Radial Basis Function [RBF] 3.0, Kane, Emmetropia verifying optical [EVO], Ladas Super, and Pearl-DGS) in patients who underwent cataract surgery after acute primary angle closure (APAC).

METHODS

In this retrospective cross-sectional study, 44 eyes of 44 patients (APAC) and 60 eyes of 60 patients (control) were included. We compared the mean absolute error, median absolute error (MedAE), and prediction error after surgery. Subgroup analyses were performed on whether axial length (AL) or preoperative laser peripheral iridotomy affected the postoperative refractive outcomes.

RESULTS

In the APAC group, all formulas showed higher MedAE and more myopic shift than the control group (all P < 0.05). In APAC eyes with AL ≥ 22 mm, there were no differences in MedAEs according to the IOL formulas; however, in APAC eyes with AL < 22 mm, Haigis (0.49 D) showed lower MedAE than SRK/T (0.82 D) (P = 0.036) and Hill-RBF 3.0 (0.54 D) showed lower MedAE than SRK/T (0.82 D), Hoffer Q (0.75 D) or Kane (0.83 D) (P = 0.045, 0.036 and 0.027, respectively). Pearl-DGS (0.63 D) showed lower MedAE than Hoffer Q (0.75 D) and Kane (0.83 D) (P = 0.045 and 0.036, respectively). Haigis and Hill-RBF 3.0 showed the highest percentage (46.7%) of eyes with PE within ± 0.5 D in APAC eyes with AL < 22 mm. Iridectomized eyes did not show superior precision than the non-iridotomized eyes in the APAC group.

CONCLUSIONS

Refractive errors in the APAC group were more myopic than those in the control group. Haigis and Hill-RBF 3.0 showed high precision in the eyes with AL < 22 mm in the APAC group.

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.

A systemic review and network meta-analysis of accuracy of intraocular lens power calculation formulas in primary angle-closure conditions

BACKGROUND

For primary angle-closure and angle-closure glaucoma, the fact that refractive error sometimes deviates from predictions after intraocular lens (IOL) implantation is familiar to cataract surgeons. Since controversy remains in the accuracy of IOL power calculation formulas, both traditional and network meta-analysis on formula accuracy were conducted in patients with primary angle-closure conditions.

METHODS

A comprehensive literature search was conducted through Aug 2022, focusing on studies on intraocular lens power calculation in primary angle-closure (PAC) and primary angle-closure glaucoma (PACG). A systemic review and network meta-analysis was performed. Quality of studies were assessed. Primary outcomes were the mean absolute errors (MAE) and the percentages of eyes with a prediction error within ±0.50 diopiters (D) or ±1.00 D (% ±0.50/1.00 D) by different formulas.

RESULTS

Six retrospective studies involving 419 eyes and 8 formulas (Barrett Universal II, Kane, SRK/T, Hoffer Q, Haigis, Holladay I, RBF 3.0 and LSF) were included. SRK/T was used as a reference as it had been investigated in all the studies included. Direct comparison showed that none of the involved formula outperformed or was defeated by SRK/T significantly in terms of either MAE or % ±0.50/1.00 D (all P>0.05). Network comparison and ranking possibilities disclosed BUII, Kane, RBF 3.0 with statistically insignificant advantage. No significant publication bias was detected by network funnel plot.

CONCLUSIONS

No absolute advantage was disclosed among the formulas involved in this study for PAC/PACG eyes. Further carefully designed studies are warranted to evaluate IOL calculation formulae in this target population.

TRAIL REGISTRATION

Registration: PROSEPRO ID: CRD42022326541.

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

PURPOSE

To explore the impact of preoperative lens vault (LV) on the accuracy of the Barrett Universal Ⅱ, Haigis, Hoffer Q, Hoffer QST, Holladay 1, Kane, and SRK/T formulas in eyes with a shallow anterior chamber.

DESIGN

Retrospective case series.

METHODS

Included were 409 eyes with anterior chamber depth (ACD) shallower than 3.0 mm that underwent phacoemulsification. Eyes were divided into a short axial length (AL) group (<22.00 mm) and a normal AL group (22.00 ≤ AL < 24.50 mm). Each group was further divided into a small LV subgroup (LV <0.95 mm) and a large LV subgroup (LV ≥0.95 mm) according to the median of the preoperative LV. Postoperative refraction was measured 3 months after surgery. Mean absolute error (MAE) was calculated and compared for each formula. The correlation between LV and the mean numeric error predicted by each formula was analyzed.

RESULTS

Overall, the Barrett and Kane formulas generated the smallest MAE in both short AL and normal AL groups (P < .05 for both). In short AL eyes with small LV, the Haigis formula performed better than other traditional formulas (P < .05 for all). In normal AL eyes with a small LV, the Barrett and Kane formulas showed higher accuracy (P < .05 for all), and other formulas were comparable. In either subgroup with a large LV, the Haigis formula created a significant higher MAE (P < .001 for all), followed by Hoffer QST. Positive correlations were found between LV and mean numeric errors predicted by all formulas, except for Barrett and Kane formulas (P < .001 for all), indicating a postoperative hyperopic shift with an increased LV.

CONCLUSIONS

In shallow anterior chamber eyes with a large LV, the Haigis and Hoffer QST formulas taking preoperative ACD into calculation surprisingly showed a larger prediction error. However, the Barrett and the Kane formulas, which include both ACD and lens thickness as predictive parameters, showed good accuracy in both small and large LV subgroups. Therefore, although formulas referring to preoperative ACD are generally believed to achieve better refractive results in patients with a shallow anterior chamber, LV may be valuable to consider when choosing an IOL power calculation formula.

Prediction of effective Lens position using anterior segment optical coherence tomography in Chinese subjects with angle closure

Purpose

To assess the accuracy of biometric parameters measured by anterior segment optical coherence tomography (AS-OCT) and partial coherence interferometry (PCI) in prediction of effective lens position (ELP) compared with previous formulas in PACG patients.

Methods

121 PACG eyes were randomly divided into training set (85 eyes) and validation set (36 eyes) with same procedure including AS-OCT, PCI, phacoemulsification and IOL implantation surgery. Preoperative anterior chamber depth (pre-ACD), scleral spur depth (SSD), scleral spur width (SSW), lens vault (LV) and cornea thickness (CT) were measured from AS-OCT image. Axial length (AL) and corneal power (K) were measured by PCI. All the 7 parameters were analyzed by multiple linear regression in training set and a statistic regression formula was developed. In validation set, one-way ANOVA was applied to compare the new regression formula with Sanders-Retzlaff-Kraff theoretic (SRK/T), Holladay 1, Haigis, and a regression formula developed in previous study.

Results

The coefficient of determination (R²) of different parameter combinations are 0.19 (pre-ACD, AL), 0.25 (AL, K) and 0.49 (SSD, AL, SSW) in training set. In validation set, the correlation between predicted and measured ELP are: new formula (R² = 0.50, P = 0.9947) Holladay 1 (R² = 0.12, P < 0.0001), SRK/T (R² = 0.11, P < 0.0001) and Haigis (R² = 0.06, P < 0.0001).

Conclusion

Among 7 tested parameters, pre-ACD contribute little in ELP prediction. Formula consist of SSD, AL and SSW showed better accuracy than other formulas tested.

Development and Evaluation of the Prognostic Nomogram to Predict Refractive Error in Patients With Primary Angle-Closure Glaucoma Who Underwent Cataract Surgery Combined With Goniosynechialysis

Objective: To evaluate the accuracy of different intraocular lens (IOL) power calculation formulas and develop prognostic nomograms to predict the risk of postoperative refractive error in primary angle-closure glaucoma (PACG) patients. Methods: A total of 111 eyes with PACG underwent goniosynechialysis combined with phacoemulsification and IOL implantation were included. SRK/T, Barrett II, Hoffer Q, and Kane formulas were used to predict postoperative refraction. Prediction error (PE) and absolute predictive error (APE) produced by the four formulas were calculated and compared. An APE >0.50 D was defined as the event. Binary logistic regression analysis and prognostic nomogram models were conducted to investigate reliable predictors associated with postoperative refraction. Results: The Kane (-0.06 D) and Barrett II (-0.07 D) formulas had mean prediction error close to zero (p = 0.44, p = 0.41, respectively). The Hoffer Q and SRK/T produced significantly myopic outcomes (p = 0.003, p = 0.013, respectively). The percentage of eyes within ± 0.5 D was 49.5% (55/111), 44.1% (49/111), 43.2% (48/111), and 49.5% (54/111), for the Kane, Barrett II, Hoffer Q, and SRK/T formula, respectively. Nomogram showed that AL had the greatest impact on the refractive outcomes, indicating a shorter preoperative AL is associated with a greater probability of refractive error event. The area under the receiver operator curve (AUC) of the nomogram for the Kane, Barrett II, Hoffer Q, and SRK/T was 0.690, 0.701, 0.708, and 0.676, respectively. Conclusions: The Kane and Barrett II formulas were comparable, and they outperformed Hoffer Q and SRK/T in the total eyes with PACG receiving cataract surgery combined with goniosynechialysis. The developed nomogram models can effectively predict the occurrence of postoperative refractive error events.

Refractive outcomes among glaucoma patients undergoing phacoemulsification cataract extraction with and without Kahook Dual Blade goniotomy

BACKGROUND

Glaucoma patients undergoing phacoemulsification alone have a higher rate of refractive surprise compared to patients without glaucoma. This risk is further increased with combined filtering procedures. Indeed, there are few and conflicting reports on the effect of combined phacoemulsification and micro-invasive glaucoma surgery (MIGS). Here, we look at refractive outcomes of glaucoma patients undergoing phacoemulsification with and without Kahook Dual Blade (KDB) goniotomy.

METHODS

Retrospective chart review of 385 glaucomatous eyes of 281 patients, which underwent either phacoemulsification alone (n = 309) or phacoemulsification with KDB goniotomy (n = 76, phaco-KDB) at the University of Colorado. The main outcome was refractive surprise defined as the difference in target and postoperative refraction spherical equivalent greater than ±0.5 Diopter (D).

RESULTS

Refractive surprise greater than ±0.5 D occurred in 26.3% of eyes in the phaco-KDB group and 36.2% in the phacoemulsification group (p = 0.11). Refractive surprise greater than ±1.0 D occurred in 6.6% for the phaco-KDB group and 9.7% for the phacoemulsification group (p = 0.08). There was no significant difference in risk of refractive surprise when pre-operative IOP, axial length, keratometry or performance of KDB goniotomy were assessed in univariate analyses.

CONCLUSION

There was no difference between refractive outcomes of glaucomatous patients undergoing phacoemulsification with or without KDB goniotomy.

Accuracy of the refractive prediction determined by intraocular lens power calculation formulas in high myopia

Purpose:

Our study was conducted to evaluate and compare the accuracy of the refractive prediction determined by the calculation formulas for different intraocular lens (IOL) powers for high myopia.

Methods:

This study reviewed 217 eyes from 135 patients who had received cataract aspiration treatment and IOL implantation. The refractive mean numerical error (MNE) and mean absolute error (MAE) of the IOL power calculation formulas (SRK/T, Haigis, Holladay, Hoffer Q, and Barrett Universal II) were examined and compared. The MNE and MAE at different axial lengths (AL) were compared, and the percentage of every refractive error absolute value for each formula was calculated at ±0.25D, ±0.50D, ±1.00D, and ±2.00D.

Results:

In all, 98 patients were recruited into this study and 98 eyes of them were analyzed. We found that Barrett Universal II formula had the lowest MNE and MAE, SRK/T and Haigis formulas arrived at similar MNE and MAE, and the MNE and MAE calculated by Holladay and Hoffer Q formula were the highest. Barrett Universal II formulas have the lowest MAE among different AL patients, whereas it reached the highest percentage of refractive error absolute value within 0.5D in this study. The MAE of each formula is positively correlated with AL.

Conclusion:

Barrett Universal II formula rendered the lowest predictive error compared with SRK/T, Haigis, Holladay, and Hoffer Q formulas. Thus, Barrett Universal II formula may be regarded as a more reliable formula for high myopia.

Effects of Choroidal Thickness on Refractive Outcome Following Cataract Surgery in Primary Angle Closure

Purpose

To identify the preoperative biometric factors, including subfoveal choroidal thickness (CT), associated with refractive outcome after cataract surgery in eyes with primary angle closure (PAC).

Methods

This study included 50 eyes of 50 PAC patients who underwent uneventful cataract surgery. Preoperatively, anterior segment parameters including anterior chamber depth (ACD) and lens vault were determined by anterior segment optical coherence tomography. Subfoveal CT was measured by spectral domain optical coherence tomography enhanced depth imaging before and at one month after surgery. Mean refractive error (MRE) was calculated as the difference in spherical equivalent between actual postoperative refraction determined one month postoperatively and that predicted using each of three IOL calculation formulas (SRK/II, SRK/T, and Haigis). Regression analyses were performed to investigate potential associations between MRE and putative factors.

Results

Mean ACD was 1.9 ± 0.4 mm, and preoperative subfoveal CT was 250.8 ± 56.9 µm. The SRK/T (MRE, 0.199 ± 0.567 diopters [D]) and Haigis (MRE, 0.190 ± 0.727 D) formulas showed slight hyperopic shift, while the SRK/II formula demonstrated a myopic shift (MRE, −0.077 ± 0.623 D) compared with that expected after cataract surgery. Mean absolute refractive error was not significantly different between formulas. Higher preoperative lens vault and shallower ACD were associated with a hyperopic shift in all formulas, but not in a statistically significant manner. Thicker preoperative subfoveal choroid was associated with a myopic shift after cataract surgery in all formulas (SRK/II: β = −0.511, p < 0.001; SRK/T: β = −0.652, p < 0.001; Haigis: β = −0.671, p < 0.001). Greater postoperative reduction of subfoveal CT was associated with a myopic shift after cataract surgery in all formulas (SRK/II: β = −0.511, p < 0.001; SRK/T: β = −0.652, p < 0.001; Haigis: β = −0.671, p < 0.001).

Conclusions

Our results indicate that preoperative subfoveal CT and the difference between pre- and postoperative subfoveal CT are significant factors for predicting refractive error after cataract surgery in PAC patients. These findings should be considered when performing cataract surgery to optimize visual outcomes.

Clear lens extraction for the management of primary angle closure glaucoma: surgical technique and refractive outcomes in the EAGLE cohort

BACKGROUND

To describe the surgical technique and refractive outcomes following clear lens extraction (CLE) in the Effectiveness, in Angle-closure Glaucoma, of Lens Extraction trial.

METHODS

Review of prospectively collected data from a multicentre, randomised controlled trial comparing CLE and laser peripheral iridotomy. Eligible participants were ≥50 years old and newly diagnosed with (1) primary angle closure (PAC) with intraocular pressure above 30 mm Hg or (2) PAC glaucoma. We report the postoperative corrected distance visual acuity (CDVA) and refractive outcomes at 12 and 36 months postoperatively for those who underwent CLE.

RESULTS

Of the 419 participants, 208 were randomised to CLE. Mean baseline CDVA was 77.9 (SD 12.4) letters and did not change significantly at 36 months when mean CDVA was 79.9 (SD 10.9) letters. Mean preoperative spherical equivalents were +1.7 (SD 2.3) and +0.08 (SD 0.95) diopters (D) at 36 months. Fifty-nine per cent and 85% eyes were within ±0.5D and ±1.0D of predicted refraction, respectively, at 36 months.

CONCLUSIONS

Mean CDVA in patients undergoing CLE for angle-closure glaucoma appeared stable over the 3-year study period. Refractive error was significantly reduced with surgery but refractive predictability was suboptimal.

TRIAL REGISTRATION NUMBER

Preoperative Expectations and Postoperative Outcomes of Visual Functioning among Cataract Patients in Urban Southern China

Purpose

To investigate the relationship between preoperative expectations and actual postoperative outcomes of visual function (VF) among patients undergoing first eye cataract surgery.

Methods

A longitudinal study of 182 patients from hospitals in urban Southern China were surveyed prior to surgery and 3 month after cataract surgery regarding their preoperative, expected postoperative and actual postoperative VF for each of the items on the Catquest-9SF and their satisfaction with cataract surgery. In addition, detailed clinical data were collected preoperatively and postoperatively.

Results

The majority of cataract patients in urban Southern China had high expectations for VF outcomes after cataract surgery and in most cases postoperative outcomes achieved the expected level of improvement. The mean (standard deviation, SD) preoperative Catquest-9SF score was 15.7 (5.86) and the mean (SD) expected postoperative score was 26.3 (2.93). The discrepancy between actual and expected improvement was significantly correlated with patients’ health literacy, presence of systemic and ocular comorbidity, preoperative visual acuity of the surgery eye, LOCS III nuclear opalescence and cortical cataract grading.

Conclusion

Cataract patients in urban Southern China had high expectations for surgery outcomes. Patients with low level of health literacy and the presence of systemic and ocular comorbidity may need a comprehensive counseling to decrease the discrepancy regarding expected and actual outcomes.