The Role of Anterior Chamber Depth on Post-operative Refractive Error After Phacovitrectomy

The predictive value of anterior segment optical coherence tomography for postoperative corneal edema in cataract patients

OBJECTIVE

To evaluate the predictive value of anterior segment optical coherence tomography (AS-OCT) for postoperative corneal edema in cataract patients.

METHODS

A retrospective cohort study of 144 cataract patients from December 2020 to December 2021 was conducted. Patients were divided into edema eyes (84 cases) and observation (60 cases) group based on postoperative corneal edema occurrence. Relevant indicators were compared between groups. Logistic regression identified risk factors for postoperative corneal edema. Receiver operating characteristic curves evaluated the predictive value.

RESULTS

The edema eyes group had significantly higher postoperative central corneal thickness (CCT) and lower postoperative endothelial cell density (ECD) than the observation group (P < 0.05). The edema eyes group also had significantly lower preoperative ECD, anterior chamber depth (ACD), anterior chamber angle (ACA), and preoperative lens position (LP) than the observation group (P < 0.05). Logistic regression analysis showed that preoperative ECD, ACD, ACA, and LP were independent risk factors for postoperative corneal edema (P < 0.05), all of which also showed good predictive value for postoperative corneal edema, with areas under the curve (AUCs) of 0.854, 0.812, 0.791, and 0.778, respectively, under the ROC curve analysis.

CONCLUSION

AS-OCT can provide useful information for predicting postoperative corneal edema in cataract patients. Preoperative ECD, preoperative ACD, preoperative ACA, and preoperative LP are important parameters that can be measured by AS-OCT and used as risk factors for postoperative corneal edema.

Comparing clinical outcomes of Optiwave Refractive Analysis, Lenstar, and surgeon's modified method for intraocular lens power calculation in Asian eyes

The study aimed to compare the accuracy of intraocular lens (IOL) calculation to predict postoperative refraction by Optiwave Refractive Analysis (ORA), Lenstar LS 900, and the surgeon's Modify method in normal Asian eyes. The IOL power of the Lenstar group was calculated according to Lenstar LS 900, whereas the surgeon's Modify group used topography, axial length (AL) of Lenstar, and Barrett Universal II online formula. Intraoperative aphakic measurements and IOL power calculations were obtained with the ORA system. From the results acquired through Lenstar, Modify, and ORA, the surgeon used his judgment to select the actual IOL power. Postoperative manifest refraction spherical equivalent (MRSE) was obtained 2 months after surgery. The prediction error (PE) was calculated as the difference between the postoperative MRSE and the target refraction proposed by three methods. AL, anterior chamber depth (ACD, measured from corneal endothelium to lens), lens thickness (LT), and ACD + 1/2LT were also included in the survey. In 67 eyes, the average real PE was smaller for the Lenstar (0.06 ± 0.44) and Modify (- 0.05 ± 0.40) than for the ORA group (- 0.25 ± 0.60, p < 0.05). The ORA system demonstrated the best results of IOL power selection in eyes with a normal range of ACD + 0.5 LT (5.2-5.6 mm) in Asian eyes.

ACCURACY OF NEW INTRAOCULAR LENS CALCULATION FORMULAE IN EYES UNDERGOING SILICONE OIL REMOVAL/PARS PLANA VITRECTOMY-CATARACT SURGERY

PURPOSE

To investigate the performance of novel intraocular lens calculation formulae (Barrett Universal II, Emmetropia Verifying Optical, and Kane) and conventional formulae (Haigis, Hoffer Q, Holladay 1, and Sanders-Retzlaff-Kraff/T [SRK/T]) in patients who underwent pars plana vitrectomy or silicone oil removal combined with cataract surgery.

METHODS

In total, 301 eyes from 301 patients who underwent pars plana vitrectomy/silicone oil removal with concomitant cataract surgery were enrolled and divided into the following four groups according to preoperative diagnosis: silicone oil-filled eyes after pars plana vitrectomy, epiretinal membrane, primary retinal detachment, and macular hole.

RESULTS

Barrett Universal II exhibited the smallest mean absolute error (0.65 diopters [D]) and median absolute error (0.39 D) in total. In patients with primary retinal detachment, each formula exhibited the worst refractive outcomes in diverse vitreoretinal pathologies ( P < 0.01), and no difference in accuracy between the seven formulas was observed ( P = 0.075). For long eyes, the second linear (Wang-Koch 2) version of the Wang-Koch adjustment significantly reduced the median absolute error for Holladay 1 and SRK/T ( P < 0.001 and P = 0.019).

CONCLUSION

In combined surgery, both new and conventional formulas using the second linear version of the Wang-Koch 2 adjustment demonstrated satisfactory performance, with Barrett Universal II exhibiting the best overall performance. However, in patients with primary retinal detachment, all seven formulas showed less favorable performance.

Rotational stability of plate haptic toric intraocular lenses after combined 25-gauge vitrectomy and cataract surgery

AIM

To evaluate the postoperative intraocular lens (IOL) rotational stability and residual refractive astigmatism following combined 25-gauge vitrectomy and cataract surgery with implantation of a plate haptic toric IOL.

METHODS

In this retrospective case series, 32 eyes of 32 patients underwent a combined 25-gauge vitrectomy and phacoemulsification for vitreoretinal diseases and cataract with regular corneal astigmatism of at least 1 diopter (D). A plate haptic toric IOL (AT Torbi 709M, Carl Zeiss Meditec AG) was implanted in all eyes. The outcome measures were rotational stability and refractive astigmatism up to 6mo postoperatively as well as the best corrected visual acuity (BCVA).

RESULTS

Preoperative refractive astigmatism was 2.14±1.17 D, which was significantly reduced to 0.77±0.37 D six to eight weeks postoperatively and remained stable throughout the observation period (0.67±0.44 D at three months and 0.75±0.25 D at six months; for all groups: P<0.0001 compared to baseline). BCVA improved significantly from 0.36±0.33 logMAR preoperatively to 0.10±0.15 logMAR following surgery (P=0.02). Mean IOL axis deviation from the target axis was 3.4°±2.9° after six to eight weeks and significantly decreased over time (2.4°±2.6° six months after surgery; P=0.04). In one patient IOL, re-alignment was performed.

CONCLUSION

Corneal astigmatism is significantly reduced following combined 25-gauge vitrectomy and cataract surgery. The plate haptic toric IOL position and axis remain stable during the observation period of six months.

Postoperative Refractive Outcomes of Biometric Formulas in Phacovitrectomy with Gas Tamponade

PURPOSE

To investigate the refractive accuracy of intraocular lens (IOL) power calculation for biometric formulas in phacovitrectomy.

METHODS

This retrospective study included 357 eyes of 357 patients who underwent phacovitrectomy using four commonly available IOL power formulas: Hoffer Q (87 eyes), Holladay 1 (78 eyes), Holladay 2 (91 eyes), and SRK/T (101 eyes). The mean refractive error (ME) and the mean absolute refractive error (MAE) were calculated based on the predicted postoperative refraction error, and they were compared using analysis of variance test. Subjects were divided into high myopic eyes (axial length, ≥26 mm) and nonhigh myopic eyes (axial length, <26 mm).

RESULTS

The ME and the MAE after phacovitrectomy did not show a significant difference among the four IOL power formulas (p = 0.546 and p = 0.495, respectively). There was no significant statistical difference in formulas when the eyes were grouped into high myopia and nonhigh myopia (ME: p = 0.526 and p = 0.482, respectively; MAE: p = 0.715 and p = 0.627, respectively). The ME showed myopic shift in all formulas regardless of IOL formula used. The ME showed greater myopic shift in high myopia group than nonhigh myopia group in all formulas.

CONCLUSIONS

Our study did not find evidence for superiority of any formula in phacovitrectomy. However, in phacovitrectomy, possible myopic shift should be considered for IOL power calculation. Especially, in phacovitrecotmy in patients with high myopia, more myopic shift should be considered when selecting IOL.

Influence of endotamponade on anterior chamber depth and refractive outcome after combined phacovitrectomy: case-control study

PURPOSE

To compare the changes in the anterior chamber depth (ACD) and in the refractive outcomes after combined phacovitrectomy with respect to the endotamponade (balanced salt solution, air, sulfur hexafluoride [SF 6 , gas]).

SETTING

Department of Ophthalmology, University Hospital Ulm, Ulm, Germany.

DESIGN

Retrospective, longitudinal case-control study.

METHODS

160 eyes of 160 patients were included in the study. 120 eyes underwent phacoemulsification with in-the-bag implantation combined with vitrectomy and were divided into 3 groups according to tamponade (balanced salt solution, air, gas). 40 control eyes with cataract surgery only were included. Further inclusion criteria were uneventful surgery, no postoperative complications and absence of corneal pathology. Endpoints were ACD as measured by swept-source optical coherence tomography-based biometry (IOLMaster 700) preoperatively, 1 to 2 days and 6 weeks postoperatively and refractive prediction error (PE) using the Barrett and Haigis formulas.

RESULTS

Within the first 2 days after surgery the ACD was shallower in the eyes left with gas or air tamponade, when compared with balanced salt solution or cataract surgery alone ( P < .001). This effect diminished 6 weeks later, and all eyes reached comparable ACD ( P = .396). The refractive PE was slightly, but statistically significantly higher in the gas group when compared with cataract surgery alone ( P = .012 for Barrett, P = .006 for Haigis).

CONCLUSIONS

The resulting ACD after combined phacovitrectomy was independent of the tamponade used, but a gas-tamponade was associated with a higher refractive PE.

Detection of Anterior Hyaloid Membrane Detachment Using Deep-Range Anterior Segment Optical Coherence Tomography

The visibility of anterior hyaloid membrane (AHM) and Berger’s space in phakic eyes was investigated. In 624 eyes of 624 patients, the retrolental space was scanned with the deep-range anterior segment optical coherence tomography (AS-OCT, CASIA2, Tomey). Subgroup analysis was conducted in 223 eyes undergoing cataract surgery. The logistic regression analysis using the backward-elimination method was performed to evaluate the influence of various factors on the visibility of AHM (dependent variable). Explanatory variables included age, gender, axial length, corneal power, corneal cylinder, and the Co III gradings. Intrarater repeatability for AHM visibility was excellent with the prevalence-adjusted bias-adjusted kappa (κ coefficient) of 0.90. AHM was observed in 43 eyes (6.9%). The patients with visible AHM (68.1 ± 8.8 years) were significantly older than those without visible AHM (52.6 ± 25.6 years) (p < 0.001). The logistic regression analysis in the cataract surgery subgroup revealed that axial length (p = 0.030) and corneal power (p = 0.043) were significantly associated with AHM visibility. The mean absolute refractive error from target was significantly larger in eyes with visible AHM (0.670 ± 0.384 D) than with invisible AHM (0.494 ± 0.412 D) (p = 0.037). The postoperative refractive prediction was less accurate in eyes with visible AHM, but no significant tendency existed in terms of myopic or hyperopic shifts.