Combined phacoemulsification and transpupillary drainage of silicone oil: results and complications

Silicone Oil Tamponade for Therapy of Primary Retinal Detachment in Patients Who Live at High Altitudes

BACKGROUND

Uncomplicated rhegmatogenous retinal detachment (RRD) is mainly treated with vitrectomy and gas tamponade or, alternatively, scleral buckling surgery. However, gas tamponade inflates at high altitudes, causing significant complications. Silicone oil (SO) tamponade volume is unaffected by atmospheric pressure and may be used in patients who live or must undertake travel at high altitudes.

PURPOSE

To determine the anatomical and functional outcomes after pars plana vitrectomy (PPV) with SO tamponade in primary uncomplicated RRD.

METHODS

Twenty-eight consecutive cases of patients operated between January 2017 and December 2022 in Jules-Gonin University Eye Hospital in Lausanne were included in this retrospective study. All patients had a follow-up of at least 3 months after SO removal.

RESULTS

Primary reattachment was achieved in all 28 eyes. Mean follow-up was 17.2 months (range: 3 - 51 months) after SO removal. Mean age at the time of intervention was 60 years (range: 21 - 80 years). Vision was stabilized or improved in 27 eyes (96%). One patient demonstrated a slight visual acuity decrease due to cataract formation at the last follow-up. In all patients, SO was removed 2 to 5 months after primary repair. In 14 of the 21 phakic patients, concomitant cataract surgery was performed. No surgical complications were encountered. Postoperatively, 5 (18%) patients had ocular hypertension, presumably steroid related, that was successfully controlled with topical treatment.

CONCLUSION

PPV with SO injection seems to be a safe and efficient surgical approach in the treatment of primary uncomplicated RRD in patients living at high altitudes and was associated with good anatomical and functional outcome in our series. However, the need for a follow-up surgery to remove SO should be weighed in these cases.

Corneal Astigmatism Alteration after Combined Silicone Oil Removal and Cataract Surgery with Intraocular Lens Implantation

Purpose

To explore short-term changes in corneal astigmatism after combined silicone oil removal and cataract (SORC) surgery.

Methods

We enrolled 89 patients (43 men and 46 women). Zeiss IOLMaster was used to measure corneal astigmatism status and axial length on the day before and after the SORC surgery. Best-corrected visual acuity (BCVA) and intraocular pressure (IOP) were recorded. The results were compared to the outcomes at 3 days, 1 week, and 1 month postoperatively.

Results

Compared to baseline, K1 decreased significantly at 3 days postoperatively (P = 0.016), 1 week (P = 0.009), and 1 month (P = 0.035), while K2 increased significantly at 3 days postoperatively (P = 0.002), 1 week (P < 0.001), and 1 month (P = 0.001), as well as corneal astigmatism (all P < 0.001). Compared to that at the baseline, BCVA significantly improved at 3 days, 1 week, and 1 month postoperatively (all P < 0.001). Meanwhile, IOP decreased significantly at 3 days postoperatively (P < 0.001), 1 week (P = 0.005), and 1 month (P = 0.007). Similarly, axial length decreased at all follow-up time points (all P < 0.001).

Conclusion

Corneal astigmatism increased in the short term after the SORC operation but gradually decreased at 1 month postoperatively. BCVA improved steadily, and SORC was widely used in the clinic.

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.

Microincision phacoemulsification combined with sutureless transpupillary passive silicone oil removal

Purpose

To evaluate the outcomes of combined microincision phacoemulsification with sutureless transpupillary silicone oil (SO) removal using an irrigation probe of bimanual irrigation/aspiration.

Methods

We conducted a single-center retrospective study, including patients who had undergone phacoemulsification with transpupillary removal of SO, which had been used for intraocular tamponade after a previous pars plana vitrectomy. Outcome measures were corrected distance visual acuity (CDVA), refractive error, intraocular pressure (IOP), and endothelial cell count (ECC) evaluated preoperatively and postoperatively at 3-month follow-up. Any intraoperative or postoperative complications, duration of surgery, and final retinal status at 3 months were also noted.

Results

Seventy-four eyes (74 patients) were analyzed. The mean interval between SO placement and cataract surgery was 4.73 months (standard deviation [SD]: 1.02). CDVA improved in 66 (89.2%) eyes and remained the same in 8 (10.8%) eyes (P < 0.001). The mean postoperative spherical equivalent was -0.96D (SD: 0.75) at 3 months (P < 0.001). There was a significant drop in IOP from 15.08 mmHg (SD: 2.67) preoperatively to 11.64 mmHg (SD: 2.02) postoperatively (P < 0.001). The average ECC loss was only 5.7% at 3 months postoperatively. The mean surgical duration was 17.20 min (SD: 7.02). One patient had retinal redetachment and required resurgery. At 3 months, the retina was attached in all patients.

Conclusion

Combined microincision phacoemulsification with transpupillary passive SO removal using irrigation probe of bimanual irrigation/aspiration is a safe, effective, and less invasive technique that offers the main advantage of reduced surgical trauma, and should be reserved for patients with a stable retina, not requiring additional surgical intervention.

Topical Review: Causes of Refractive Error After Silicone-oil Removal Combined with Cataract Surgery

SIGNIFICANCE

This review summarizes the main factors of refractive error after silicone oil removal combined with cataract surgery.The post-operative refractive results of silicone oil removal combined with cataract surgery are closely related to the patient's future vision quality. This report summarizes the factors that influence the difference between the actual post-operative refractive power and the pre-operatively predicted refractive power after silicone oil removal combined with cataract surgery, including axial length, anterior chamber depth, silicone oil, commonly used tools for measuring intraocular lens power, and intraocular lens power calculation formulas, among others. The aim of the report is to assist clinical and scientific research on the elimination of refractive error after silicone oil removal combined with cataract surgery.

Safety and efficacy of transpupillary silicone oil removal in combination with micro-incision phacoemulsification cataract surgery: comparison with 23-gauge approach

Background

To evaluate safety and efficacy of transpupillary silicone oil removal combined with micro-incision phacoemulsification cataract surgery, and to compare results of transpupillary with 23-gauge three-port vitrectomy approach.

Methods

Consecutive cases that underwent silicone oil removal using either transpupillary or three-port approach in combination with micro-incision phacoemulsification cataract surgery were retrospectively reviewed. The main outcome measures were postoperative detachment rate, silicone oil residuals, best corrected visual acuity (BCVA) and intraocular pressure (IOP).

Results

A total of 64 cases were included, 19 in transpupillary and 45 in three-port. Postoperative detachment rate within 3 months in transpupillary versus three-port was 15.8% versus 4.4% (p = 0.14), Silicone oil residuals was 7.4 ± 3.2% versus 7.1 ± 2.8% (transpupillary vs. three-port, p = 0.71). Preoperative versus postoperative BCVA (logMAR) was 1.49 ± 0.61 versus 1.42 ± 0.61 in transpupillary approach (p = 0.28) and 1.53 ± 0.48 versus 1.45 ± 0.57 in three-port approach (p = 0.11). Transpupillary approach resulted in lower IOP at postoperative day 2 (12.2 ± 2.3 mmHg vs. 13.5 ± 2.2 mmHg, p < 0.05), while postoperative follow-up at 1 month revealed no significant difference (p = 0.21).

Conclusions

Transpupillary silicone oil removal combined with micro-incision phacoemulsification cataract surgery is less invasive and can be an alternative in some circumstances.

Final anatomic and visual outcomes appear independent of duration of silicone oil intraocular tamponade in complex retinal detachment surgery

AIM

To report anatomic and visual outcomes following silicone oil removal in a cohort of patients with complex retinal detachment, to determine association between duration of tamponade and outcomes and to compare patients with oil removed and those with oil in situ in terms of demographic, surgical and visual factors.

METHODS

We reported a four years retrospective case series of 143 patients with complex retinal detachments who underwent intraocular silicone oil tamponade. Analysis between anatomic and visual outcomes, baseline demographics, duration of tamponade and number of surgical procedures were carried out using Fisher's exact test and unpaired two-tailed t-test.

RESULTS

One hundred and six patients (76.2%) had undergone silicone oil removal at the time of review with 96 patients (90.6%) showing retinal reattachment following oil removal. Duration of tamponade was not associated with final reattachment rate or with a deterioration in best corrected visual acuity (BCVA). Patients with oil removed had a significantly better baseline and final BCVA compared to those under oil tamponade (P=0.0001, <0.0001 respectively).

CONCLUSION

Anatomic and visual outcomes in this cohort are in keeping with those reported in the literature. Favorable outcomes were seen with oil removal but duration of oil tamponade does not affect final attachment rate with modern surgical techniques and should be managed on a case by case basis.

Timing and outcomes after silicone oil removal in proliferative vitreoretinopathy: a retrospective clinical series

OBJECTIVE

To evaluate anatomical and functional outcomes after silicone oil extraction in patients with retinal detachment and proliferative vitreoretinopathy in an eye care referral center in Joinville, SC, southern Brazil.

METHODS

Retrospective, noncomparative study of patients with retinal detachment and posterior proliferative vitreoretinopathy followed up after silicone oil removal. Prophylactic 360-degree peripheral laser photocoagulation was performed one to three months before silicone oil extraction. Patients with cataract underwent a combined clear corneal phacoemulsification with intraocular lens implantation in the same procedure. Anatomical outcomes were related to the duration of silicone oil tamponade and the surgical procedure performed. Functional outcomes were divided into three categories (stability, worsening, or improvement) according to visual acuity variation before the surgery and at the last follow-up visit.

RESULTS

Fifty-three patients were followed up for a mean period of 1,262 days. Fourteen eyes (26.4%) underwent cataract surgery combined with silicone oil extraction. Forty-eight eyes (90.5%) had attached retina at the last follow-up examination. Time of intraocular tamponade and association of phacoemulsification with silicone oil extraction were not considered as risk factors for retinal redetachment. Twenty-three cases (43.4%) showed visual acuity improvement, whereas 11 cases (20.8%) were stable and 19 cases (35.8%) showed visual acuity worsening. Five patients with attached retina had unexplained optic disc atrophy.

CONCLUSION

Most patients had good anatomical and visual outcomes after silicone oil extraction. Prophylactic 360-degree laser retinopexy may have led to favorable outcomes. Benefits of silicone oil extraction and the associated risks of complications due to a new surgical procedure must be carefully evaluated before surgical indication.

Refractive outcomes after silicone oil removal and intraocular lens implantation

PURPOSE

To evaluate the accuracy of intraocular lens (IOL) calculations in eyes undergoing silicone oil removal and IOL implantation using ultrasound biometry and partial coherence interferometry (PCI) (IOLMaster).

METHODS

This was a retrospective consecutive series of eyes that underwent silicone oil removal and IOL implantation from 1999 to 2009. Data were collected on preoperative and intraoperative characteristics that could affect the refractive outcome. The predicted refraction, as measured with ultrasound biometry or PCI, was compared with the postoperative refraction.

RESULTS

Overall, the mean difference between observed and predicted refraction was -0.97 diopters (D). Thirty-five of 64 eyes (55%) were measured by ultrasound biometry, and 29 of 64 eyes (45%) were measured by PCI. The mean (SD) difference between the predicted refraction and the observed spherical equivalent was -1.34 D (2.18 D) when measured by biometry and -0.51 D (2.03 D) when measured by PCI (P = 0.13).

CONCLUSION

Refractive outcomes after silicone oil removal and secondary IOL implantation are fairly accurate, with most ending up slightly myopic. Measurement by PCI may be more accurate than biometry. The IOL power should be selected to yield a target refraction about 0.5 D to 1.25 D more hyperopic than desired, depending on the method used to measure it.

Evaluation of limbal and pars plana silicone oil removal in aphakic eyes

PURPOSE

To compare limbal and pars plana silicone oil removal (SOR) in aphakic eyes and to evaluate the acute effect of silicone oil flow to the corneal endothelium.

METHODS

Sixteen aphakic patients with silicone oil endotamponade requiring SOR were recruited for this prospective study and randomly scheduled for limbal or pars plana SOR. The central corneal thickness (CCT), visual acuity (VA) and intraocular pressure were measured preoperatively, on the first postoperative day and 4 months after surgery. Endothelial cell density (ECD) was measured preoperatively and at the end of follow-up. The in vitro study was performed on ten enucleated porcine eyes. Corneoscleral discs were prepared and fixed on artificial anterior chamber followed by 2.5-mm limbal incision and 5-ml silicone oil injection in six cases and 5 ml balanced salt solution (BSS) in four cases.

RESULTS

The ECD decreased by 239.2 ± 86.7 (13.9%) and 86.7 ± 22.4 cells/mm(2) (5%) after limbal (n = 8) and pars plana SOR (n = 8), respectively (p < 0.001 for both). The difference between the groups was significant (p < 0.001). A significant increase in CCT and corresponding decrease in VA was noted on the first postoperative day using both procedures. At the end of follow-up, the CCT and VA were comparable to initial values. Postoperative hypotony (≤6 mmHg) was observed more frequently after limbal SOR. In the experiment, lamellar abrasions of corneal endothelium were observed after silicone oil injection, whereas no changes were observed after BSS injection.

CONCLUSION

Limbal SOR causes more considerable damage to the corneal endothelium than the pars plana approach because of mechanical abrasion.

Combined phacoemulsification and transpupillary removal of heavy silicone oil

We describe a technique for heavy silicone oil removal combined with phacoemulsification and intraocular lens insertion without scleral incisions or sutures using a modified 16-gauge cannula. The technique is less invasive than other techniques for removing silicone oil and does not interfere with the uveal tract or the peripheral retina.

REFRACTIVE OUTCOME OF SILICONE OIL REMOVAL AND INTRAOCULAR LENS IMPLANTATION USING LASER INTERFEROMETRY

PURPOSE

To evaluate the refractive outcome of silicone oil removal and intraocular lens (IOL) implantation using laser interferometry.

METHODS

Thirteen silicone oil-filled eyes of 12 patients were included in the study. IOL power calculation was performed using laser interferometry (IOLMaster V1.1; Carl Zeiss, Jena, Germany). All of these eyes underwent silicone oil removal and cataract extraction with IOL implantation. Post-operative refraction was evaluated.

RESULTS

The mean deviation of the final post-operative refraction (spherical equivalent) was -0.30+/-0.91 D (range, -1.87 to +1.3) at 12 weeks. The mean axial length of the eyes was 22.99+/-0.84 mm (range, 22.07-25.24 mm). No major complications occurred intra- or post-operatively.

CONCLUSION

Laser interferometry appears to be a feasible and satisfactorily accurate method to calculate IOL power in some silicone oil-filled eyes. Further studies comparing this technique to others are warranted.

Cataract surgery and transpupillary silicone oil removal through a single scleral tunnel incision under topical anesthesia; sutureless surgery

The author evaluated the results of combined cataract extraction and transpupillary silicone oil removal through a single scleral tunnel incision, in eyes that had undergone pars plana vitrectomy with silicone oil tamponade. Twenty-four of the 46 eyes were operated on under topical anesthesia with Blumenthal mode mini-nucleus manual extracapsular cataract extraction technique (mini-nuc ECCE), and silicone oil was removed passively through planned posterior capsulorhexis via the scleral tunnel, followed by endocapsular intraocular lens (IOL) implantation. The operation was completed without any suturing. The remaining 22 eyes were similarly operated on with the same cataract extraction technique, but in these cases silicone oil was classically aspirated actively through pars plana sclerotomies. Results were evaluated by visual acuity measurement, duration of operation, and complications. The transpupillary silicone oil removal group had significantly less vitreous hemorrhage (0- 31.8%) and posterior capsule opacification (0-36.4%). Also, the mean duration of the operation was significantly shorter in this group. There was no significant difference between the two groups with regard to postoperative recurrence of retinal detachment (12.5-18.1%) and visual acuity outcome. The combination of mini-nuc ECCE with transpupillary silicone oil removal compares favorably with the combination of silicone oil aspiration through pars plana sclerotomies. This combined technique allows the surgeon to perform the operation under topical anesthesia and no sutures are required. The intervention period is shorter and no posterior capsule opacification or vitreous hemorrhage develops.

Cataract surgery and silicone oil removal: visual outcome and complications in a combined vs. two step surgical approach

PURPOSE

To compare visual outcome and complications of two surgical strategies for patients who needed cataract surgery and silicone oil removal.

METHODS

A prospective, nonrandomized study was performed to compare two groups of patients who had cataract surgery and silicone oil removal from April 1998 to January 2002. From April 1998 to November 1999, patients had two surgical sessions with cataract surgery before silicone oil removal (Group 1), and from December 1999 to January 2002, patients underwent combined cataract surgery and silicone oil removal in a single session (Group 2).

RESULTS

Thirty-five patients were included in each group. The postoperative visual acuity improved by at least two lines of Snellen in 13 patients (37.1%) in Group 1 and 15 (42.8%) patients in Group 2 (P=0.63). The mean visual improvement was 0.12 lines and 0.13 lines in groups 1 and 2 (P=0.62). Complications in groups 1 and 2 included transient intraocular pressure rise (25.7% versus 28.5%), retinal detachment (14.2% versus 11.4%), fibrin reaction (5.7% in both groups), and persistent intraocular pressure rise (2.8% in both groups).

CONCLUSION

The visual outcome and complication rates were similar in both groups. Combined surgery offers the advantages of a single surgical event and a faster visual rehabilitation. We therefore suggest a surgical approach with combined cataract surgery and silicone oil removal in selected patients with a stable retinal situation.

Phacoemulsification with transpupillary silicone oil removal and lens implantation through a corneal incision using topical anesthesia

PURPOSE

To evaluate phacoemulsification combined with transpupillary silicone oil removal and foldable intraocular lens (IOL) implantation through a single corneal incision and planned posterior capsulorhexis after pars plana vitrectomy using topical anesthesia.

SETTING

Department of Ophthalmology, University of Bari, Bari, Italy.

METHODS

This noncomparative nonrandomized noncontrolled interventional case series comprised 34 consecutive patients (34 eyes). The mean age of the 25 men and 9 women was 54.4 years +/- 13.3 (SD). A mean of 8.2 +/- 9.4 months after silicone oil injection, patients had phacoemulsification with transpupillary silicone oil removal and foldable acrylic IOL implantation through a single corneal incision and a planned posterior capsulorhexis under topical anesthesia. Patients were operated on by the same surgeon. Visual acuity, the frequency of retinal redetachment, secondary cataract and vitreous hemorrhage formation, subjective pain and discomfort, the duration of surgery, and intraocular pressure (IOP) were noted. The mean follow-up was 9.4 +/- 5.1 months (range 4 to 21 months).

RESULTS

Vision improved or stabilized in 88.2% of eyes. Retinal redetachment occurred in 4 eyes (11.8%) and transient vitreous hemorrhage in 1 (2.9%). All patients reported minimal discomfort during the procedure. The mean duration of surgery was 17 +/- 4 minutes. There was no significant intraoperative or postoperative IOP variation.

CONCLUSIONS

Combined phacoemulsification, transpupillary silicone oil removal, and IOL implantation through a single corneal incision under topical anesthesia was safe and effective. In general, the visual outcomes were good with improvement in visual acuity.

Evaluation of corneal damage by combined phacoemulsification and passive efflux of silicone oil in vitrectomized eyes

PURPOSE

To evaluate the effect on the corneal endothelium of phacoemulsification combined with passive silicone oil removal and intraocular lens (IOL) implantation under topical anesthesia after pars plana vitrectomy.

SETTING

Department of Ophthalmology and Otolaryngology, University of Bari, Bari, Italy.

METHODS

This retrospective study evaluated the corneal endothelium in 17 consecutive patients (17 eyes) who had phacoemulsification with transpupillary passive silicone oil washout (1300 centistokes) through a posterior capsulorhexis and single clear corneal incision and foldable acrylic IOL implantation. The findings were compared with those in a control group of 17 patients (17 eyes) who had phacoemulsification with acrylic IOL implantation through a single clear corneal incision. All procedures were performed by the same surgeon using topical anesthesia. The preoperative and postoperative endothelial cell densities, coefficient of variation (CV), and percentage of hexagonal cells at the corneal center and peripheral temporal position, evaluated by noncontact specular microscopy, were compared between the 2 groups. The central corneal thickness and occurrence of keratopathy were also noted.

RESULTS

The mean phacoemulsification and total ultrasound times did not differ significantly between the 2 groups. At 6 months, the mean endothelial cell loss was 284.50 cell/mm(2) +/- 462.3 (SD) (11.2%) in the study group and 200.15 +/- 117.9 cell/mm(2) (8.3%) in the control group (P=.87, unpaired t test). There were no significant between-group differences in the increase in the mean CV and the percentage of hexagonal cells. The mean pachymetry remained at preoperative values, with no difference between groups. Keratopathy was not observed in any patient.

CONCLUSIONS

Passive silicone oil efflux caused significant endothelial cell loss and changes in endothelial morphology. Nevertheless, these modifications were well tolerated and minimally different from the results of trauma caused by standard phacoemulsification with posterior chamber IOL implantation.

The problems of biometry in combined silicone oil removal and cataract extraction: a clinical trial

PURPOSE

To evaluate the problems and accuracy of biometry in eyes that have been operated on by silicone oil removal combined with cataract extraction with or without intraocular lens implantation.

SUBJECTS AND METHODS

Twenty-nine consecutive cases that have been operated on for silicone oil removal and cataract, with or without intraocular lens implantation, were included in a prospective study. Axial length measurement was done in silicone oil-filled eyes after changing the sound speed in vitreous cavity to 987 m/sec. The SRKT formula was used for intraocular lens calculation. The cataract was removed by phacoemulsification through corneal section or phacofragmentation through the standard vitrectomy sclerotomy. Intraocular lens implantation was done either on the peripheral anterior capsule (single piece, PMMA) or in the bag (acrylic foldable three pieces). The final refraction after at least 3 months' follow-up was measured. The difference between the predicted and the actual refraction was evaluated. A control group of 30 consecutive cases (20 nonmyopic and 10 highly myopic) of cataract extraction and intraocular lens implantation in eyes not filled with silicone oil was included using the same evaluation methods.

RESULTS

The mean deviation of the final from the predicted refraction was 1.87 +/- 2.11 diopters (range, +3.25 to -9 diopters). A total of 72.4% had a deviation of +/-2 diopters. The mean deviation in high myopia was 3.04 +/- 2.68 diopters (12 cases) (range, +/-1.75 to -9 diopters), while in nonmyopic patients, the mean deviation was 1.04 +/- 1.04 diopters (17 cases) (range, +3.25 to -3.25 diopters). The difference between highly myopic and nonmyopic eyes was statistically significant (P < 0.05). Most high errors occurred in highly myopic eyes. There was no statistical difference between the types of silicone oil (1000 versus 5000) or the mode of cataract extraction (phacoemulsification versus pars plana phacofragmentation). In the control group, the mean deviation in high myopia was 1.48 +/- 1.02 diopters (10 cases) (range, +/-0.5 to -3.5 diopters), while in nonmyopic patients, the mean deviation was 0.65 +/- 0.75 diopters (20 cases) (range, +2.75 to -1.75 diopters). The difference was statistically significant (P < 0.05).

CONCLUSION

Intraocular lens calculation in silicone oil-filled eyes is accurate in eyes that are not highly myopic. Some highly myopic eyes with posterior staphyloma have great deviation. Unsuitable formula, artifacts, or large eyes beyond the machine range may be the cause of errors of deviation of refraction. Comparable results are obtained in eyes regardless of the type of silicone oil (1000 or 5000) and techniques of intraocular lens implantation (in the sulcus or in the bag).