Intraoperative biometry for intraocular lens (IOL) power calculation at silicone oil removal

Simplifying biometry in oil-filled eyes: A novel formula for axial length calculation in eyes with 1000 cSt silicone oil

Purpose

To derive a formula for accurate axial length (AL) assessment using routine ultrasound in silicone oil-filled eyes, where optical biometry is unavailable or not possible.

Methods

This was a prospective, consecutive, nonrandomized study of 50 eyes of 50 patients conducted in a tertiary care hospital in North India. AL measurements were taken using both manual A-scan and IOL master, both in silicone oil-filled status and 3 weeks after silicone oil removal. A correction factor of 0.7 was used for AL adjustment in oil-filled eyes. The corrected AL (cAL) was compared with IOL master values in oil-filled eyes. Agreement analysis was carried out using Bland Altman plot. Linear regression analysis was done using uncorrected manual AL to find a new equation. Data was analyzed using Stata 14. A P value <0.05 was taken as significant.

Results

The study included 40 males and 10 females, with an age range of 6-83 years (mean 41.9 years). The mean AL of the oil-filled eye as measured by manual A-scan was 31.76 mm ± 3.09 and by IOL master was 24.7 mm ± 1.74. Linear regression analysis was performed in randomly selected 35 eyes of the observed data to obtain a new equation: predicted AL (PAL) = 14 + 0.3 × manual AL. The mean difference between PAL and optically measured AL with silicone oil in situ was 0.98 ± 1.67.

Conclusion

We propose a new formula for better prediction of the correct AL in silicone oil-filled eyes using ultrasound-based AL measurement.

Evaluation and comparison of ocular biometric parameters obtained with Tomey OA-2000 in silicone oil-filled aphakic eyes

PURPOSE

To evaluate a new non-contact instrument (OA-2000) measuring the ocular biometry parameters of silicone oil (SO)-filled aphakic eyes, as compared with IOLMaster 700.

METHODS

Forty SO-filled aphakic eyes of 40 patients were enrolled in this cross-sectional clinical trial. The axial length (AL), central corneal thickness (CCT), keratometry ((flattest keratometry) Kf and (steep keratometry, 90° apart from Kf) Ks), and axis of the Kf (Ax1) were measured with OA-2000 and IOLMaster 700. The coefficient of variation (CoV) was calculated to assess the repeatability. The correlation was evaluated by the Pearson coefficient. Bland-Altman analysis and paired t test were used to analyze the agreements and differences of parameters measured by the two devices, respectively.

RESULTS

The mean AL obtained with the OA-2000 was 23.57 ± 0.93 mm (range: 21.50 to 25.68 mm), and that obtained with the IOLMaster 700 was 23.69 ± 0.94 mm (range: 21.85 to 25.86 mm), resulting in a mean offset of 0.124 ± 0.125 mm (p < 0.001). The mean offset of CCT measured by OA-2000 and IOLMaster 700 was 14.6 ± 7.5 μm (p < 0.001). However, the Kf, Ks and Ax1 values from the two devices were comparable (p > 0.05). All the measured parameters of the two devices showed strong linear correlations (all r ≥ 0.966). The Bland-Altman analysis showed a narrow 95% limits of agreement (LoA) of Kf, Ks and AL, but 95%LoA of CCT and Ax1 was wide, which were - 29.3 ~ 0.1 μm and-25.9 ~ 30.7°respectively. The CoVs of the biometric parameters obtained with OA-2000 were lower than 1%.

CONCLUSION

In SO-filled aphakic eyes, the ocular parameters (including AL, Kf, Ks, Ax1, and CCT) measured by the OA-2000 and IOLMaster 700 had a good correlation. Two devices had an excellent agreement on ocular biometric measurements of Kf, Ks and AL. The OA-2000 provided excellent repeatability of ocular parameters in SO-filled aphakic eyes.

Outcomes of combined phacoemulsification/intraocular lens implantation and silicon oil removal

PURPOSE

To evaluate the outcomes and complications of simultaneous silicon oil removal (SOR) and phacoemulsification and intra ocular lens implantation.

METHODS

In this retrospective non-comparative case series, the visual, refractive and anatomical outcomes of patients who underwent combined phacoemulsification/silicone oil removal (5700 centistokes) surgery between 2017 and 2019 in a single center were evaluated.

RESULTS

Forty-four eyes of 44 patients (eighteen males) were included. The mean age of the patients was 51.45 ± 11.59 years. The primary pathology was tractional retinal detachment (TRD) secondary to diabetic retinopathy in 36 eyes and rhegmatogenous retinal detachment (RRD) in 8 eyes. The median time period between silicone oil tamponade and removal was 9 months. There was no statistically significant difference between best corrected visual acuity (-0.14 ± 0.69 LogMAR, p= 0.19) and intraocular pressure (p= 0.26) before and after the surgery. Mean post-operative spherical equivalent (SE) at last visit was 0.36 ± 1.64 which was different from the target refraction (- 0.5D). After cataract/SOR surgery, one eye (2.3%) developed retinal re-detachment in RRD patient. Vitreous hemorrhage occurred in nine eyes (20.5%) which all had TRD as the primary pathology.

CONCLUSION

Combined phacoemulsification, silicone oil and IOL implantation removal surgery seems to be a safe and useful procedure with high success rate and acceptable visual, refractive and anatomical outcomes.

Different lens power calculation formulas for the prediction of refractive outcome after phacoemulsification with silicone oil removal

Background

Formulas predicting intraocular lens power have not been compared in silicone oil-tamponaded eyes. The study aims to compare six intraocular lens power assessment formulas in silicone oil-tamponaded eyes.

Methods

This prospective study included patients with silicone oil-tamponaded eyes scheduled for silicone oil removal, phacoemulsification, and intraocular lens implantation at Chongqing Aier Eye Hospital (June 2019 to December 2019). Implanted intraocular lens power was used to predict postsurgical spherical equivalence using SRK/T, Holladay 1, Holladay 2, Haigis, Hoffer Q, and Barrett Universal II, and assess those formula’s predictive accuracy with predictive error.

Results

The analysis included 47 eyes in 47 patients (28 and 19 eyes with normal and long axial length, respectively). Postoperative spherical equivalence at 6 months in normal and long axial length eyes was − 0.6 ± 0.96 and − 0.8 ± 1.52 D, respectively. Predictive error values for SRK/T, Holladay 1, Holladay 2, Haigis, and Hoffer Q and Barrett Universal II were − 0.18 ± 0.92, − 0.15 ± 0.88, − 0.06 ± 0.94, − 0.15 ± 0.87, and − 0.05 ± 0.90 D and − 0.06 ± 0.90, respectively, for normal axial length eyes and 0.15 ± 1.16, 0.46 ± 1.17, 0.28 ± 1.11, − 0.04 ± 1.12, 0.49 ± 1.09 D and 0.11 ± 0.99, respectively, for long axial length eyes. For normal axial length eyes, predicted outcomes were similar to actual outcomes for all formulas. For long axial length eyes, predicted outcomes differed significantly from measured postsurgical values for Holladay 1, Holladay 2, and Hoffer Q (P < 0.05) but not SRK/T or Haigis or Barrett Universal II .

Conclusions

The formulas had comparable predictive accuracy in silicone oil-tamponaded eyes with normal axial length, but Haigis or SRK/T or Barrett Universal II may be preferable in long axial length eyes.

Trial registration

ChiCTR1900023215.

Refractive outcomes of a single-step and a two-step approach for silicone oil removal and cataract surgery

Purpose:

To compare the intermediate-term refractive outcomes of a single-step and a two-step approach for silicone oil removal (SOR) and cataract surgery.

Methods:

Case records of patients who had SOR and phacoemulsification (PE) from 2011 to 2013 at a tertiary center in South India were retrospectively analyzed. A total of 135 eyes that underwent ultrasound biometry (UB) were studied. Eighty-seven eyes had SOR and PE at a single surgery (Group A), where as UB was done in a silicone oil (SO) filled eye. Forty-eight eyes had SOR followed by PE later (Group B), where UB was done in a fluid-filled eye. The refractive error (RE) and best-corrected visual acuity (BCVA) at postoperative day 45 (D45) and postoperative month 3 (M3) were compared.

Results:

Baseline axial length, intraocular lens (IOL) power, and RE in both groups were comparable. A myopic shift (4.18 ± 5.47 diopters [D]) was noted in 92% eyes at M3. Forty-nine percent eyes had a RE of ≤±1.5D at M3. RE at D45 and at M3 was significantly lesser in Group B (−1.73 ± 2.04 vs. −0.64 ± 1.75; P, 0.002). BCVA was significantly lesser in Group A at baseline, at D45, and at M3 (P < 0.01 for all). There was no difference in other baseline characteristics of eyes that had RE ≤±1.5D and those that had RE >±1.5D at M3.

Conclusion:

SO-filled eyes had a myopic shift in refraction after SOR and PE. When UB is used for IOL power calculation, better refractive outcomes are obtained when SOR and PE are performed in a two-step approach.

Visual Outcomes and Refractive Status after Combined Silicone Oil Removal/Cataract Surgery with Intraocular Lens Implantation

Purpose:

To evaluate refractive status and identify predictors of surgical success following a combined silicone oil removal/cataract surgery with intraocular lens (IOL) implantation procedure.

Methods:

In this single-armed, retrospective study, we reviewed patients who underwent vitreoretinal surgery followed by a combined silicone oil removal/cataract surgery procedure between 2009 and 2013. Preoperative data included patient demographics, refractive status, IOL power, and axial length (measured with the IOL Master). Postoperative data were obtained from the 8-week follow-up visit and from the last follow-up visit attended that included refractive error (RE) evaluation (e.g., myopic, hyperopic, and astigmatic). Associations between variables and refractive status were examined. Blindness was defined as a best-corrected visual acuity (BCVA) worse than 3/60.

Results:

Nighty-eight eyes were ultimately included in analyses. Following surgery, 37.0% of eyes achieved BCVA better than 6/18. The incidence of blindness (BCVA worse than 3/60) was reduced from 47.0% before surgery to 17.3% after surgery. Additionally, 33.7% of eyes did not require refractive correction. Forty-two percent of eyes were under-corrected (>0.5 D hyperopia) following surgery. Age, gender, silicone oil viscosity, axial length, IOL type, initial vitreoretinal pathology, surgeon, and IOL calculation formula were not significantly associated with surgical outcomes (all P > 0.05).

Conclusion:

A combined silicone oil removal/cataract surgery with IOL implantation procedure restored functional vision in approximately one-third of cases. However, nearly half of patients were under-corrected. Unfortunately, we did not identify any factors that predicted surgical success.

Phacoemulsification combined with transpupillary removal of silicone oil and intracapsular intraocular lens implantation

AIM

To estimate the effectiveness of phacoemulsification and foldable intraocular lens (IOL) implantation combined with transpupillary silicone oil removal.

METHODS

There were 168 eyes of 168 candidate patients with cataract and silicone oil-filled eyes recruited in our study. All of the patients received the intraocular silicone oil removal surgery by transpupillary drainage and cataract extraction by phacoemulsification. Then the IOL implantation were also performed through corneal incision.

RESULTS

The surgery was successfully completed in all eyes. Best corrected visual acuity (BCVA) and postoperative complications were recorded in three months after surgery. There were 143 eyes with BCVA improved, otherwise 25 eyes remained stable at the last follow-up visit. The mean BCVA statistically improved from 20/400±0.02 to 20/100±0.15 (P<0.001) and mean postoperative IOP was 13.85±2.18 mm Hg (P=0.415). No intra-operative complications were reported.

CONCLUSION

Phacoemulsification combined with transpupillary removal of silicone oil is a safe and simple effective method. In general, it enables quick recovery of visual acuity with less complication rate.

Accuracy and reliability of IOL master and A-scan immersion biometry in silicone oil-filled eyes

PURPOSE

To compare the accuracy and reliability of intraocular lens (IOL) master and A-scan immersion biometry in silicone oil (SO)-filled eyes.

METHODS

A prospective, consecutive, nonrandomized study was performed in 34 SO-filled eyes of 34 patients, who underwent a pars plana vitrectomy, with SO removal and cataract surgery, as well as IOL implantation. Both IOL master and immersion A-scan were performed to measure the axial length (AXL) before SO removal. Three months after removal of the SO, AXL measurements using IOL master and refraction was performed. Accuracy of the two techniques was determined by a mean postoperative AXL using an IOL master and reliability was determined by mean actual postoperative refractive error.

RESULTS

Preoperative mean AXL was 23.91±0.24 mm (range 21.33-28.61 mm) and 23.71±0.59 mm (range 19.27-36.18 mm) by IOL master and A-scan immersion, respectively. Postoperative mean AXL by IOL master was 23.90±0.23 mm (range 21.58-27.94 mm), which showed a statistically significant difference from the preoperative mean AXL by A-scan immersion (P=0.005). The AXL measurement by IOL master also was more accurate than A-scan immersion by Pearson's correlation (0.966 vs 0.410). For reliability of the two techniques, the predictive postoperative refractive error in A-scan immersion (mean 1.79±1.04 D, range -14.62 to 16.41 D) was greater than that in IOL master (mean 0.60±0.23 D, range -2.74 to 2.33 D), with a statistically significant difference (P=0.049).

CONCLUSION

IOL master had more accuracy and less deviation in predictive postoperative refractive error than A-scan immersion in SO-filled eyes.

Reliability of the IOLMaster in axial length evaluation in silicone oil-filled eyes

PURPOSE

To assess the reliability of IOLMaster in axial length (AL) measurement in phakic silicone oil-filled vs pseudophakic saline-filled eyes.

METHODS

Ten eyes of 10 patients, vitrectomized with silicone oil tamponade and scleral buckled with significant lens opacity were enrolled. Optical biometry with IOLMaster (Carl Zeiss Meditec AG, Germany) was performed 1 day before and 1 week after silicone oil removal and phacoemulsification with artificial intraocular lens (IOL) implantation in order to assess changes in AL measurements.

RESULTS

Mean AL was 26.16+/-1.23 mm (range 24.64-28.8 mm) and 26.27+/-1.46 mm (range 25.26-29.6 mm), respectively, the day before and 1 week after silicone oil removal and cataract surgery, and the difference was not statistically significant (P=0.2).

CONCLUSIONS

Presence vs absence of silicone oil tamponade as well as phakic vs pseudophakic status in buckled and vitrectomized eyes did not influence the AL measurement by means of no-contact optical biometry, suggesting that such eyes might be candidate for silicone oil removal and cataract surgery at one time.