The role of the vitreous body in effective IOL positioning

Refractive outcome in combined phacovitrectomy: Anterior segment changes and corrective factor for IOL power calculation improvement

PURPOSE

To analyze differences in refractive outcome Δ (difference between postoperative and expected refractive error) and in anterior segment changes between cataract surgery patients and combined phacovitrectomy patients. We also aimed to provide a corrective formula allowing to minimise the refractive outcome Δ in combined surgery patients.

METHODS

Candidates for phacoemulsification and combined phacovitrectomy (respectively PHACO and COMBINED groups) were prospectively enrolled in two specialised centres. Patients underwent best corrected visual acuity (BCVA) assessment, ultra-high speed anterior segment optical coherence tomography (OCT), gonioscopy, retinal OCT, slit lamp examination and biometry at baseline, 6 weeks postoperatively and 3 months postoperatively.

RESULTS

No differences in refractive Δ, refractive error and anterior segment parameters were noted between PHACO and COMBINED group (109 and 110 patients respectively) at 6 weeks. At 3 months, COMBINED group showed a spherical equivalent of -0.29 ± 0.10 D versus -0.03 ± 0.15 D in PHACO group (p = 0.023). COMBINED group showed a significantly higher Crystalline Lens Rise (CLR), angle-to-angle (ATA) and anterior chamber width (ACW) and a significantly lower anterior chamber depth (ACD) and refractive Δ with all 4 considered formulas at 3 months. For IOL power lower than 15, a hyperopic shift was observed instead.

CONCLUSIONS

Anterior segment OCT suggests anterior displacement of the effective lens position in patients undergoing phacovitrectomy. A corrective formula can be applied to IOL power calculation to minimize undesired refractive error.

Outcomes of Secondary Intracapsular Intraocular Lens Implantation in Patients following Rhegmatogenous Retinal Detachment

This study reports the outcomes of a secondary IOL implantation technique in patients that suffered from rhegmatogenous retinal detachment combined with a cataract, which included reopening the capsular bag, enabling secondary intracapsular intraocular lens (IOL) implantation. We included consecutive cases with rhegmatogenous retinal detachment (RRD) treated with vitrectomy and silicone oil tamponade, and subsequent secondary IOL implantation during silicone oil removal between September 2019 and June 2022. Demographics, pre- and postoperative clinical data, and complications were collected. Visual and refractive outcomes and IOL position were evaluated. Thirty eyes were included and followed up for a mean of 24.2 ± 5.06 months. Compared with the preoperative values, no significant changes were observed in the intraocular pressure (p = 0.170) and endothelial cell density (p = 0.336); however, the best-corrected visual acuity (Snellen: 20/83 vs. 20/38; logMAR: 0.66 ± 0.23 vs. 0.37 ± 0.32; p < 0.001) and spherical equivalent (p < 0.001) improved significantly. The mean prediction error (ME) was -0.45 ± 0.68 D (-1.9-0.54 D), and the mean absolute prediction error (MAE) was 0.62 ± 0.52 D (0.01-1.9 D). The macula-on subgroup demonstrated significantly better refractive outcomes than the macula-off subgroup (ME, p = 0.046; MAE, p = 0.008). The IOL was well positioned, with a mean horizontal and vertical tilt and decentration of 0.53 ± 0.49° and 0.21 ± 0.16 mm, and 0.54 ± 0.45° and 0.22 ± 0.16 mm, respectively. Secondary intracapsular IOL implantation provided a good and stable IOL position and satisfactory refractive outcomes, and is a feasible treatment option for patients with RRD.

The Postvitrectomy Cataract

To review the recent literature regarding risk factors for cataract formation after vitrectomy, the challenges and management strategies for anterior segment surgeons when facing post-vitrectomy cataract surgery, and the visual outcomes of patients undergoing post-vitrectomy cataract surgery. Cataract surgery after vitrectomy can be safely performed to significantly improve the visual outcome in most post-vitrectomy patients, although final visual acuity is primarily limited by the patient’s underlying vitreoretinal pathology.

Influence of combined phacovitrectomy without tamponade on intraocular lens displacement and postoperative refraction

PURPOSE

To compare phacoemulsification versus phacovitrectomy regarding postoperative intraocular lens (IOL) shift and refraction.

METHODS

This prospective bilateral comparison study included 40 eyes of 20 patients. Inclusion criteria were combined phacovitrectomy without gas/air tamponade in one eye and cataract surgery in the contralateral eye with implantation of the same IOL. Postoperative anterior chamber depth (ACD) was compared between both groups 1-5 hr, 1 day and 8 weeks after surgery. Postoperative refraction was compared after 8 weeks using the Holladay I, HofferQ, SRK/T, Haigis and Barrett formulae.

RESULTS

There were no intergroup differences in ACD (8 weeks: 0.02 mm absolute difference, SD 0.22, range -0.36 to 0.65, p = 0.401), mean absolute refractive error (8 weeks: Holladay I p = 0.452; HofferQ p = 0.475; SRK/T p = 0.498; Haigis p = 0.869; and Barrett p = 0.352) or percentages within the 0.5 D and 1.0 D range at any time-point. All formulae were optimized for the phacovitrectomy and the cataract groups. There was no correlation of macular thickness change and refractive error (cataract group r²  = -0.13, p = 0.58; phacovitrectomy group r²  = -0.10, p = 0.68).

CONCLUSION

Combined phacovitrectomy without air/ gas tamponade caused neither ACD displacement nor refractive shifts compared to phacoemulsification alone. Surgically induced macular thickness change had no significant influence on postoperative refraction in this study. All five IOL formulae showed comparable postoperative refractive outcomes.

Influence of lens position as detected by an anterior segment analysis system on postoperative refraction in cataract surgery

AIM

To predict postoperative intraocular lens (IOL) position using the Sirius anterior segment analysis system and investigate the effect of lens position and IOL type on postoperative refraction.

METHODS

A total of 97 patients (102 eyes) were enrolled in the final analysis. An anterior segment biometry measurement was performed preoperatively with Sirius and Lenstar. The results of predicted lens position (PLP) and IOL power were automatically calculated by the software used by the instruments. Effective lens position (ELP) was measured manually using Sirius 3mo postoperatively. Pearson's correlation analysis and linear regression analysis were used to determine the correlation of lens position to other parameters.

RESULTS

PLP and ELP were positively correlated to axial length (AL; r=0.42, P<0.0001 and r=0.49, P<0.0001, respectively). There was a weak correlation between the peLP (ELP-PLP) and the prediction error of spherical refraction (peSR; r=0.34, P<0.0001). The peLP of Softec HD IOL differed statistically from those of both the TECNIS ZCB00 and Sensor AR40E IOLs. Multiple linear regression was used to obtain the prediction formula: ELP=0.66+0.63×[aqueous depth (AQD)+0.6LT] (r=0.61, P<0.0001), and a new variable (AQD+0.6 LT) was found to have the strongest correlation with ELP.

CONCLUSION

The Sirius anterior segment analysis system is helpful to predict ELP, which reduces postoperative refraction error.

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

Purpose

To investigate the effect of phacovitrectomy on the post-operative anterior chamber depth (ACD) and refractive outcomes, and to analyze the potential differences between vitreous filling with BSS, air and gas.

Methods

Patients who underwent phacovitrectomy were included in this study and invited for repeated post-operative examination including refraction and biometry at least 3 months after the surgery. Data retrieved included demographic information, indication for phacovitrectomy, surgical details, type of vitreous filling (BSS, air or gas), pre-operative and post-operative biometric data including K-readings, axial length (AL), and ACD, as well as spherical equivalent (SE) values of the target and final refraction.

Results

Forty-three eyes of 43 patients were included in this study, including 10 eyes filled with BSS, 18 with air and 15 with gas. The mean difference between the final measured spherical equivalent (SE) and the SE of the intended target refraction was 0.61±0.68 D (p = 0.019). Only 58.1% of eyes had a final SE within ±0.5D of the target refraction. Following surgery, AL remained unchanged, while mean pre-operative ACD increased significantly from 3.11±0.34 mm to 4.77±0.47 mm (p < 0.001). There was no difference in refractive error between the vitreous fillings and no correlation with AL or ACD.

Conclusions

Phacovitrectomy is associated with lower accuracy of post-operative refraction compared to cataract surgery. This may be attributed to a significant change in ACD, influencing the effective lens position of the IOL, and may require adjustment of the pre-operative calculations.

Refractive Outcomes and Anterior Chamber Depth after Cataract Surgery in Eyes with and without Previous Pars Plana Vitrectomy

Purpose: To compare the differences in refractive outcome and anterior chamber depth (ACD) after phacoemulsification between eyes with and without previous pars plana vitrectomy (PPV).Materials and Methods: Patients who had significant cataracts after PPV were included in the study group, and patients with a matched axial length (AL) who had cataracts without PPV were selected as the control group. The performance of new generation intraocular lens (IOL) power calculation formulas (Barrett Universal II, Kane, Ladas Super formulas), and the traditional formulas (SRK/T, Holladay 1, Hoffer Q, Haigis) with and without the Wang-Koch (WK) AL adjustment were compared between the two groups. The postoperative ACD was measured using the Scheimpflug imaging system with manual correction at least three months after surgery. Results: In total, there were 193 eyes from 193 patients in each group. The mean prediction errors (MEs) of the new generation formulas had no significant systemic bias in the study group; the hyperopic shift was displayed in the traditional formulas for eyes with AL > 26mm. However, the difference of MEs between the two groups among all the formulas were not significant. The absolute prediction error (MAE) and median prediction error (Med AE) in the study group were larger than those in the control group among all the formulas. The postoperative ACD of the study group was deeper but not significant than that of the control group. Conclusions: There was no refractive shift in vitrectomized eyes compared with non-vitrectomized eyes no matter in new generation formulas or traditional vergence formulas. The prediction error among all the formulas in vitrectomized eyes were significantly higher than those in non-vitrectomized eyes. The ACD after phacoemulsification in vitrectomized eyes was not significantly different from non-vitrectomized eyes.

Prospective Comparison of Intraocular Lens Dynamics and Refractive Error between Phacovitrectomy and Phacoemulsification Alone

PURPOSE

To compare intraocular lens (IOL) dynamics and refractive prediction errors between eyes that underwent phacovitrectomy and eyes that underwent phacoemulsification alone.

DESIGN

Prospective, nonrandomized, comparative, observational study.

PARTICIPANTS

Sixty eyes of 60 patients who underwent 25-gauge phacovitrectomy without gas injection for macular pathology and 60 eyes of 60 patients who underwent phacoemulsification alone for cataract were enrolled.

METHODS

Preoperative optical biometry was performed using the IOLMaster 700 (Carl Zeiss Meditec, Inc, Dublin, CA) to calculate the IOL power with the Barrett Universal II formula. Monofocal, nontoric, single-piece foldable aspherical IOLs were implanted in each patient. Comprehensive ocular examinations, including CASIA2 (Tomey Corp, Nagoya, Japan) evaluations of the preoperative crystalline lens and postoperative IOL positions (i.e., decentration, tilt, and aqueous depth), were performed before and 3 days, 1 month, and 3 months after surgery.

MAIN OUTCOME MEASURES

Refractive prediction errors and IOL dynamics.

RESULTS

Mean refractive prediction errors at 3 days, 1 month, and 3 months after phacovitrectomy were 0.51±0.59 diopters (D), 0.11±0.40 D, and 0.05±0.41 D, respectively, whereas those after phacoemulsification alone were 0.43±0.38 D, 0.11±0.37 D, and 0.07±0.34 D, respectively. There was no significant difference in the refractive error between the 2 groups at any time point. A myopic shift of -0.50 D or more negative refractive error occurred in 4 (6.7%) of 60 eyes with phacovitrectomy and 3 (5.0%) of 60 eyes with phacoemulsification alone; there was no significant between-group difference. At 3 months postoperatively, refractive errors within ±0.50 D and ±1.00 D were achieved in 49 (81.7%) and 58 (96.7%) of 60 eyes in the phacovitrectomy group and 52 (86.7%) and 60 (100.0%) of 60 eyes in the phacoemulsification alone group, again without any significant between-group differences. There were no significant differences in the preoperative lens and postoperative IOL positions between the 2 study groups, except for a significantly deeper mean aqueous depth at 3 days after surgery in the phacovitrectomy group.

CONCLUSIONS

Neither myopic shift nor IOL displacement occurs after 25-gauge phacovitrectomy with a single-piece IOL without gas injection for macular pathology compared with phacoemulsification alone.