Older age as risk factor for deviation from emmetropia in pseudophakia

The effect of patient age on some new and older IOL power calculation formulas

PURPOSE

To assess the accuracy of intraocular lens (IOL) power calculation in different age groups using various IOL calculation formulas.

METHODS

Data from 421 eyes of 421 patients ≥60 years old (ages: 60-69, n = 131; 70-74, n = 105; 75-84, n = 158 and ≥85, n = 27), who underwent uneventful cataract surgery with SN60WF IOL implantation at John A. Moran Eye Center, Salt Lake City, USA, were retrospectively obtained. The SD of the prediction error (PE), median and mean absolute PEs and the percentage of eyes within ±0.25, ±0.50, ±0.75 and ±1.00 D were calculated after constant optimizations for the following formulas: Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO) 2.0, Haigis, Hoffer Q, Hoffer QST, Holladay 1, Kane, Radial Basis Function (RBF) 3.0 and SRK/T. Results were compared between the different age groups.

RESULTS

Predictability rates within 0.25D were lower for the eldest age group compared with the other groups using the EVO 2.0 (33% vs. 37%-53%, p = 0.045), Kane (26% vs. 35%-50%, p = 0.034) and SRK/T (22% vs. 31%-49%, p = 0.002). Higher median absolute refractive errors for all formulas were observed in the oldest group [range: 0.39 D (Haigis, Hoffer QSR)-0.48 D (Kane)], followed by the youngest group [range: 0.30 D (RBF 3.0)-0.39 D (Holladay 1, SRK/T)] but did not reach statistical significance. No significant differences between the groups in the distribution parameter were seen.

CONCLUSION

Current IOL power calculation formulas may have variable accuracy for different age groups. This should be taken into account when planning cataract surgery to improve refractive outcomes.

Risk factors affecting cataract surgery outcome: The Malaysian cataract surgery registry

This is a 5 years multicentre database study that recruited subjects from the Malaysian Ministry of Health Cataract Surgery Registry (MOH CSR), aimed to determine risk factors that affect cataract surgery visual outcome and evaluates post-cataract surgery vision. All age-related cataract surgeries with primary intraocular lens (IOL) implantation were included. Cases with secondary cataract, previous ocular surgeries and incomplete data were excluded. A total of 131425 cases were included in the study. Amongst all types of cataract surgery, 92.9% attained post-operative best-corrected visual acuity better than 6/18 and the outcome improved to 97.1% when ocular comorbidities were excluded. Factors with Odds Ratio (OR) >1.5 associated with an impaired visual outcome included: elderly patients of 80 years old and above; systemic disease such as renal failure; ocular co-morbidities; pre-operative vision worse than 6/60; general anaesthesia, retrobulbar anaesthesia or subconjunctival anaesthesia; extracapsular cataract extraction (ECCE), intracapsular cataract extraction (ICCE), anterior chamber intraocular lens (ACIOL) implantation or combined cataract surgery; the presence of intra- and post-operative complications. In conclusion, a good visual outcome was achieved after cataract surgery in most cases. This large multicentre study provides information about risk factors for poor visual outcome post-cataract surgery and may serve as a basis for evidence-based guidelines.

Long-term outcomes of prediction error after combined phacoemulsification and trabeculectomy in glaucoma patients

Background

To investigate long-term outcomes of prediction error after phacotrabeculectomy and to determine risk factors that may cause unstable prediction error after phacotrabeculectomy in glaucoma patients.

Methods

A total 120 eyes of 120 patients who had underwent uncomplicated phacotrabeculectomy (combined group) or phacoemulsification (phaco-only group) were included. Best-corrected visual acuity (BCVA), intraocular pressure (IOP) were measured before and after surgery, and anterior segment parameters including anterior chamber depth (ACD), lens vault (LV), and anterior vault (AV) measured using anterior-segment optical coherence tomography were compared between the two groups. The mean absolute error (MAE) at 3, 6, 12, and 24 months postoperatively were compared. Risk factors associated with unstable prediction error (MAE ≥ 0.5) were investigated in the combined group.

Results

In both groups, BCVA was improved and IOP was decreased significantly. MAE at 3, 6, 12, 24 months postoperatively were not significantly different between two groups. The risk factors for unstable prediction error after 12 months of phacotrabeculectomy were old age and LV. Whereas, the only factor predicting unstable prediction error after 24 months of phacotrabeculectomy was LV. The cut-off value of LV for predicting unstable refractive error analyzed by the ROC curve was 0.855 mm.

Conclusions

Phacotrabeculectomy may be an effective treatment with stable long-term outcomes of prediction error similar to phacoemulsification in patients with glaucoma. However, elderly patients or patients with large LV may be predisposed to unstable prediction error after phacotrabeculectomy.

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.

Prediction Error of Intraocular Lens Power Calculation in Very Elderly Patients over 90 Years Old

BACKGROUND

To investigate the influence of age on prediction error (PE) after cataract surgery in very elderly (VE) patients aged more than 90 years.

METHODS

We retrospectively analyzed 66 eyes of patients aged ≥90 years (VE group) who underwent phacoemulsification and intraocular lens (IOL) implantation. As the control group (CG), we investigated 121 eyes of patients aged 70-89 years who underwent the same surgery. PE was calculated 1 month post-surgery as the actual postoperative spherical equivalent minus the target diopter, which was calculated using the Sanders-Retzlaff-Kraff/T formula. The absolute and arithmetic PE were compared between the two groups. The factors affecting absolute PE outside ±0.5 diopter (D) and ±1.0 D were determined through logistic regression analysis with the variables age, sex, axial length (AL), average corneal power, preoperative best-corrected visual acuity, target diopter, and coexisting pseudoexfoliation syndrome.

RESULTS

The absolute PE was significantly larger in the VE group than that in the CG (0.60 ± 0.52 D and 0.34 ± 0.25 D, respectively; P < .001). There was no significant difference in terms of arithmetic PE between the two groups (-0.06 ± 0.79 D and -0.07 ± 0.42 D, respectively; P = .653). In the logistic regression analysis, age was significantly associated with absolute PE outside ±0.50 D (Odds ratio [OR]: 1.05). Age and AL were significantly associated with absolute PE outside ±1.0 D (OR: 1.24 and 0.20, respectively).

CONCLUSIONS

Absolute PE tended to increase in the cataract surgery of VE patients.

Intraocular lens power calculation in the elderly population using the Kane formula in comparison with existing methods

PURPOSE

To assess the accuracy of the Kane formula for intraocualr lens (IOL) power calculation in comparison with established formulas in the elderly population.

SETTING

Shiley Eye Institute, University of California San Diego, USA.

DESIGN

Retrospective cohort.

METHODS

Retrospective data from 90 patients (90 eyes) aged 75 years or older who underwent uneventful cataract surgery with SN60WF intraocular lens (IOL) implantation were evaluated. The first operated eyes of patients with final corrected distance visual acuity 20/40 or better and axial length 22 to 26 mm were included. Prediction errors were calculated for Barrett Universal (BU) II, Haigis, Hoffer Q, Holladay 1, Kane, and SRK/T formulas. A subgroup analysis based on age (75-84 and ≥85 years old) was performed.

RESULTS

Use of both BUII and Kane formulas resulted in the highest percentage of eyes with prediction errors within ±0.50 diopters (D) (72% each) and significantly higher than Hoffer Q, Holladay 1, and SRK/T (P = .001). Rates of predictability within ±0.25 D and ±1.00 D were 31% to 38% and 87% to 92%, respectively, with no significant differences between formulas. No statistically significant difference was seen between formulas in the median absolute error. These tendencies remained consistent in both age groups when analyzed separately. Subgroup analysis showed better predictability of all formulas in the younger age group.

CONCLUSIONS

To the authors' knowledge, this is the first study evaluating the Kane formula exclusively in the elderly population. The Kane formula was found to be of equal accuracy to the BUII and superior to the Hoffer Q, Holladay 1, and SRK/T formulas. Very elderly patients might have reduced refractive precision using all formulas.

Inter-ocular and inter-visit differences in ocular biometry and refractive outcomes after cataract surgery

This study aimed to determine whether inter-ocular differences in axial length (AL), corneal power (K), and adjusted emmetropic intraocular lens power (EIOLP) and inter-visit differences in these ocular biometric values, measured on different days, are related to refractive outcomes after cataract surgery. We retrospectively reviewed 279 patients who underwent phacoemulsification. Patients underwent ocular biometry twice (1–4 weeks before and on the day of surgery). Patients were divided into three groups: group S (similar inter-ocular biometry in different measurements; n = 201), group P (inter-ocular differences persisted in the second measurement; n = 37), and group D (inter-ocular difference diminished in the second measurement; n = 41). Postoperative refractive outcomes (mean absolute errors [MAEs]) were compared among the groups. Postoperative MAE2, based on second measurement with reduced inter-ocular biometry difference, was smaller than that calculated using the first measurement (MAE1) with borderline significance in group D (MAE1, 0.49 ± 0.45 diopters vs. MAE2, 0.41 ± 0.33 diopters, p = 0.062). Postoperative MAE2 was greater in group P compared to the other two groups (p = 0.034). Large inter-ocular biometry differences were associated with poor refractive outcomes after cataract surgery. These results indicate that measurements with smaller inter-ocular differences were associated with better refractive outcomes in cases with inter-visit biometry differences.

Accuracy of IOL power calculations in the very elderly

Background/objectives

To analyze the refractive predictability and outcomes of cataract surgery in the very elderly (≥85 years old).

Subjects/methods

A retrospective case-series performed at the Shiley Eye Institute, University of California San Diego, USA. Electronically pulled data of 2444 surgeries revealed 147 surgeries on 133 very elderly patients. Chart review was conducted for all very elderly and corresponding control patients (75–84 years old). The first operated eyes of patients with final best-corrected visual acuity ≥20/40, axial length (AL) 22–26 mm, and implanted SN60WF IOL were included. Patients with ocular comorbidities and/or intra- or post-operative complications were excluded. Prediction errors of refractive outcome and percentage of eyes within ±0.50D and ±1.00D were compared between the groups for the Holladay 1 and Barrett Universal II (Barrett) formulas. Logistic regression analysis for achievement of ±1.00D was conducted.

Results

Final analysis included 90 eyes (n = 44, very elderly, n = 46, control patients). Median absolute refractive error (MedAE) with Holladay 1, but not Barrett formula, was significantly higher in the older group (p = 0.02 and p = 0.07, respectively). The MedAE in the older group was lower using the Barrett compared to Holladay 1 (p = 0.02). Fewer older patients than younger patients achieved refraction within ±0.50D and ±1.00D from goal, using the Holladay 1 (p = 0.049 and p = 0.002 respectively). Logistic regression analysis supported the relationship between Holladay 1 predictive refractive error of >1.00D and patient’s age (p = 0.046).

Conclusions

Very elderly patients undergoing cataract surgery may be prone to reduced refractive precision, particularly with utilization of the Holladay 1 formula.

Influence of Patient Age on Intraocular Lens Power Prediction Error

PURPOSE

To examine whether intraocular lens (IOL) power prediction error (PE) after cataract surgery differs according to patient age.

DESIGN

Prospective cohort study.

METHODS

We consecutively enrolled 75 eyes of 75 patients 59 years of age or younger, and 150 eyes of 150 patients in each of 3 age groups (60-69, 70-79, and 80-89 years), for whom phacoemulsification and implantation of a single-piece acrylic IOL was planned. The IOL power was calculated using the optimized SRK/T formula. Objective refraction was measured using an autorefractometer at approximately 3 months postoperatively, and the mean arithmetic PE and median absolute PE were compared among age groups.

RESULTS

The mean preoperative refractive error predicted by the SRK/T formula was similar among age groups (P = .4179). The mean postoperative spherical equivalent was significantly more myopic in younger patients (P < .0001). Mean PE was -0.24 diopters (D) in those ≤59 years of age, -0.17 D in those 60-69 years of age, -0.11 D in those 70-79 years of age, and -0.05 D in those 80-89 years of age; the mean PE was less myopic in older patients (P = .0008). The median absolute PE did not differ significantly among groups (P = .6192). Mean PE was positively correlated with age (P < .0001). Multiple regression analysis revealed that age, preoperative axial length, average corneal curvature, and anterior chamber depth were independent predictors of the age-related difference in PE.

CONCLUSION

PE was less myopic by approximately 0.06 D per decade as age increased, suggesting that patient age should be considered when selecting IOL power.

Achieving target refraction after cataract surgery

PURPOSE

To evaluate the difference between target and actual refraction after phacoemulsification and intraocular lens implantation at an academic teaching institution's Comprehensive Ophthalmology Service.

DESIGN

Retrospective study.

PARTICIPANTS

We examined 1275 eye surgeries for this study.

METHODS

All consecutive cataract surgeries were included if they were performed by an attending or resident surgeon from January through December 2010. Postoperative refractions were compared with preoperative target refractions. Patients were excluded if they did not have a preoperative target refraction documented or if they did not have a recorded postoperative manifest refraction within 90 days.

MAIN OUTCOME MEASURES

The main outcome measure was percentage of cases achieving a postoperative spherical equivalent ± 1.0 diopter (D) of target spherical equivalent.

RESULTS

We performed 1368 cataract surgeries from January through December of 2010. Of these, 1275 (93%) had sufficient information for analysis. Of the included cases, 94% (1196 of 1275) achieved ± 1.0 D of target refraction by 90 days after cataract surgery.

CONCLUSIONS

This paper establishes a new benchmark for a teaching hospital, where 94% of patients achieved within 1.0 D of target refraction after cataract surgery. The refractive outcomes after cataract surgery at this academic teaching institution were higher than average international benchmarks.

Paired opposite clear corneal incisions to correct preexisting astigmatism in cataract patients

PURPOSE

To evaluate the astigmatic correcting effect of paired opposite clear corneal incisions on steep axis in cataract patients.

SETTING

Sligo General Hospital, Sligo, Ireland.

METHODS

Fifteen eyes of 14 cataract patients with a mean age of 78.4 years +/- 6.38 (SD) (range 69 to 90 years) were recruited for the study. Inclusion criterion was topographic astigmatism of more than 2 diopters (D) in the cataractous eye. Preoperative refraction, autokeratometry, and topography were performed. The steep axis was marked before sub-Tenon's anesthesia was given. Paired 3-step self-sealing opposite clear corneal incisions were made 1 mm anterior to limbus on the steep axis with a 3.2 mm keratome. One incision was used for standard phacoemulsification, and the other was left unused for astigmatic correction. All the patients had day-case surgery. The first follow-up was at 1 month. Postoperative topography, keratometry, and refraction were performed on all patients.

RESULTS

Mean preoperative and postoperative topographic corneal astigmatism were 3.26 +/- 1.03 D (range 2.30 to 5.80 D) and 2.02 +/- 1.04 D (range 0.20 to 4.00 D), respectively. Mean astigmatic correction was 1.23 +/- 0.49 D (range 0.30 to 2.20 D). Mean surgically induced astigmatism by vector analysis was 2.10 +/- 0.79 D (range 0.80 to 3.36 D). There were no incision-related complications.

CONCLUSION

Paired opposite clear corneal incisions on the steep axis is a useful way to correct astigmatism in cataract patients, requiring no extra skill or instrumentation.