Cataract surgery in highly myopic eyes corrected by phakic anterior chamber angle-supported lenses(1)

Retinal complications post posterior chamber phakic intraocular lens implantation at a tertiary eye hospital in the Eastern Province of Saudi Arabia

PURPOSE

Phakic intraocular lenses treat higher degrees of myopia not possible previously with conventional refractive surgery. The aim of this study is to report the incidence and risk factors of retinal complications after posterior chamber PIOL implantation and assess the differences in biometric parameters between patients who developed such complications versus those who did not.

METHODS

This retrospective study recruited 514 patients who underwent ICL implantation to correct myopia at a tertiary eye hospital center in the Eastern province of Saudi Arabia. Follow up period was at least one year. Medical records of the patients were reviewed to obtain the required data. Associations between respondents' characteristics and retinal complications were evaluated using the Chi-squared test.

RESULTS

The mean (SD) age was 27.7 (± 6.5) years ranging from 18 to 47. Laser treatment was performed in 14 cases (2.7%). Retinal complications occurred in six cases (1.2%). The risk of retinal complication was significantly higher among patients with high axial length (OR = 1.3, 95% CI 1.2, 1.4) and patients with high pre-spherical equivalent before ICL (OR = 1.09, 95% CI 1.03, 1.4).

CONCLUSION

Patients with higher axial length and higher pre-spherical equivalent before ICL implantation are at high risk of retinal complications.

Bilensectomy: Safety and Visual Outcomes in Angle-Supported, Iris-Fixated, and Posterior Chamber Phakic Intraocular Lenses

PURPOSE

To report the visual and refractive outcomes, intraoperative and postoperative complications, and main causes of bilensectomy in the different types of phakic intraocular lenses (pIOLs).

METHODS

This was a retrospective multicenter study that included 234 eyes of 185 patients that underwent bilensectomy. Patients were divided into three groups depending on the pIOL that was explanted (angle-supported, iris-fixated, or posterior chamber). The main reasons leading to the indication for bilensectomy, time elapsed between pIOL implantation and bilensectomy, intraoperative and postoperative complications, uncorrected and corrected distance visual acuity (UDVA and CDVA), and endothelial cell density loss 1 year after bilensectomy were evaluated.

RESULTS

There was a statistically significant improvement in UDVA and CDVA after bilensectomy in all groups. Cataract development was the main reason for bilensectomy, followed by significant endothelial cell density loss. Time between pIOL implantation and bilensectomy was significantly greater in eyes with an anterior chamber pIOL.

CONCLUSIONS

Bilensectomy outcomes in general are good. Iris-fixated lenses, particularly hyperopic, are more prone to intraoperative complications and endothelial cell loss than the other pIOLs models. The results show that bilensectomy is a safe and effective procedure with a relatively low rate of intraoperative and postoperative complications and acceptable refractive predictability. [J Refract Surg. 2023;39(3):128-134.].

Refractive outcomes and complications following angle supported, iris fixated, and posterior chamber phakic intraocular lenses bilensectomy

PURPOSE OF REVIEW

The manuscript presents a review of published studies regarding the outcomes, causes, and complications of phakic intraocular lens (pIOLs) bilensectomy.All pIOLs will be explanted at some point, therefore is important to know the visual and refractive outcomes following bilensectomy.

RECENT FINDINGS

There are few publications about the outcomes following pIOL bilensectomy; in all of them, cataract remains the main cause of bilensectomy. Other causes are endothelial cell density loss and pupil ovalization. The mean time between pIOL implantation and bilensectomy is longer in eyes implanted with an anterior chamber pIOL than in eyes implanted with a posterior chamber pIOL. There is a significant improvement in uncorrected and corrected distance visual acuity after bilensectomy. Some sight-threatening complications like retinal detachment and low endothelial cell density (ECD) after surgery have been reported. Current publications suggest that endothelial cell density loss is more frequent in eyes that underwent bilensectomy for an anterior chamber pIOL.

SUMMARY

Good visual and refractive outcomes are achieved after bilensectomy, regular endothelial cell density measurements should be performed in all patients implanted with an anterior chamber pIOL to perform a safe bilensectomy.

An angle-supported foldable phakic intraocular lens for correction of myopia: A five-year follow-up

OBJECTIVE

To evaluate the efficacy and safety of an angle-supported foldable phakic intraocular lens (pIOL) for the correction of moderate to high myopia after 5 years follow-up.

METHODS

Prospective and retrospective, observational, longitudinal, non-randomised consecutive series of cases conducted on a total of 100 eyes of 67 patients with moderate to high myopia implanted with an Acrysof Cachet pIOL (Alcon Laboratories Inc.) with the aim of minimising the refractive error. The ages ranged between 18 to 60years. Uncorrected distance visual acuity (UDVA), manifest refraction, corrected distance visual acuity (CDVA), endothelial cells density, pIOL position, intraocular pressure, and complications were recorded preoperatively and during the 5 year follow-up.

RESULTS

Five years after implantation, the mean manifest spherical equivalent refraction reduced significantly from -11.62±3.35 dioptres (D) to -0.33±0.85D. UDVA was 20/20 or better in 5 of 25 cases (20%), and 20/40 or better in 22 cases (88%). CDVA was 20/20 or better in 17 cases (68%), and 20/32 or better in 23 cases (92%) of eyes. The residual refractive error was within ±0.50D of emmetropia in 12 cases (48%), and within ±1.00D in 19 cases (76%). Mean endothelial cell loss at 5 years was 11.8% central, and 13.7% peripheral. Mean endothelium-pIOL distance was 2.11±0.18mm, and mean pIOL-crystalline distance was 0.88±0.20mm.

CONCLUSIONS

This angle supported pIOL provided a favourable refractive correction and predictability, as well as acceptable safety in patients with moderate to high myopia. Although endothelial cell density decreased over 5years, the results are within the range reported in previous studies with other pIOLs.

Long-Term Observation of Triplex Surgery for Cataract after Phakic 6H Implantation for Super High Myopia

Purpose. To analyze the safety, effectiveness, and stability of triplex surgery for phakic 6H anterior chamber phakic intraocular lens explantation and phacoemulsification with in-the-bag IOL implantation for super high myopia in long-term observations. Methods. This retrospective case series evaluated 16 eyes of 10 patients who underwent triplex surgery. Best corrected visual acuity (BCVA), endothelial cell density (ECD), and associated adverse events were evaluated. Results. The mean follow-up time after the triplex surgery was 46 ± 14 months. The mean logMAR BCVA was significantly improved after triplex surgery (P = 0.047). One eye developed endophthalmitis five days postoperatively and underwent pars plana vitrectomy (PPV). Five eyes with preoperative severe endothelial cell loss developed corneal decompensation and underwent keratoplasty at a mean time of 9.4 ± 2.6 months after the triplex surgery. One eye had graft failure and underwent a second keratoplasty. The eye developed rhegmatogenous retinal detachment and underwent PPV with silicone oil 18 months later. ECD before the triplex surgery was not significantly different compared with that at last follow-up (P = 0.495) apart from these five eyes. Three eyes (18.8%) developed posterior capsule opacification. Conclusions. Triplex surgery was safe and effective for phakic 6H related complicated cataracts. Early extraction before severe ECD loss is recommended.

Phakic intraocular lens explantation: causes in 240 cases

PURPOSE

To describe the main causes of explantation of phakic intraocular lenses (PIOLs) according to the anatomical site of implantation (angle supported, iris fixated, or posterior chamber).

METHODS

This multicentric, retrospective, and consecutive study sponsored by the Spanish Ministry of Health comprised a total of 240 eyes (226 patients) explanted due to PIOL complications. Clinical data of 144 angle-supported lenses, 24 iris-fixated lenses, and 72 posterior chamber lenses explanted were recorded preoperatively and postoperatively.

RESULTS

Mean age of the patients at explantation was 46.30 ± 11.84 years (range: 25 to 80 years). The mean time between implantation and explantation was 381.14 ± 293.55 weeks (range: 0.00 to 1,551.17 weeks). It was 422.33 ± 287.81 weeks for the angle-supported group, 488.03 ± 351.95 weeks for the iris-fixated group, and 234.11 ± 4,221.60 weeks for the posterior chamber group. It was 8.10 ± 5.52 years for the angle-supported group, 9.36 ± 6.75 years for the iris-fixated group, and 4.49 ± 4.25 years for the posterior chamber group. This period of time was significantly shorter in the posterior chamber group (P < .001). Overall, the main causes of explantation were cataract formation (132 eyes, 55%), endothelial cell loss (26 eyes, 10.83%), corneal decompensation (22 eyes, 9.17%), PIOL dislocation/decentration (16 eyes, 6.67%), inadequate PIOL size or power (12 eyes, 5%), and pupil ovalization (10 cases, 4.17%). Cataract development was the cause of explantation in 51.39% of angle-supported cases, 45.83% of iris-fixated cases, and 65.28% of posterior chamber cases. Endothelial cell loss was the cause of explantation in 15.97% of angle-supported PIOLs, 8.33% of iris-fixated PIOLs, and 1.39% of posterior chamber PIOLs.

CONCLUSIONS

Cataract is the main cause of PIOL explantation, especially in posterior chamber PIOLs. In the angle-supported group, endothelial cell loss was the second cause of explantation.

Incidence rate and occurrence of visually significant cataract formation and corneal decompensation after implantation of Verisyse/Artisan phakic intraocular lens

Purpose

To evaluate the incidence rate and indications for explantation of Verisyse phakic intraocular lenses (pIOLs) over a 13.6 year period.

Subjects and methods

Case series describing six cases of explantation of Verisyse pIOLs, out of 213 eyes with Verisyse pIOLs, implanted over a 13.6 year period by one surgeon at one institution, with mean follow-up of 5.6 years per eye.

Results

Four pIOLs were removed to facilitate extraction of a visually significant cataract, one was removed due to both cataract formation and development of corneal decompensation, and another was removed due to development of localized peripheral corneal decompensation. The incidence rate of pIOL removal was five per 1,000 patient-years with pIOL. Mean time from insertion of pIOL to cataract removal was 9.3 years (range 4.0–12.6 years). Mean time from insertion of pIOL to development of corneal decompensation was 10 years (range 6.9–13 years). There was no increase in the rate of cataract extraction in the pIOL population compared to the general population.

Conclusion

Cataracts may develop in patients with pIOLs, necessitating removal of the pIOL. Corneal decompensation is a serious complication that appears to be directly related to pIOLs. Corneal decompensation can occur up to 13 years following implantation of pIOLs, and long-term follow-up is important to monitor for this complication.

Modulation transfer function of intraocular collamer lens with a central artificial hole

BACKGROUND

A modified implantable collamer lens (ICL) with a central hole (diameter 0.36 mm), "Hole-ICL", was created to improve aqueous humour circulation. The aim of this study is to investigate the effects of ICL power and the relationship between pupil size and modulation-transfer functions (MTFs) in a Hole-ICL in vitro.

METHODS

The ICL and intraocular lens (IOL) studied were the Collamer ICL (Model ICM, STAAR Surginal) and the monofocal IOL AF-1 (VA-60BBR, HOYA). The ICLs' powers were -20.0 diopters (D), -10.0 D, -5.0 D, +3.0 D, and +10.0 D. A modified ICL with a central hole (diameter 0.36 mm), "Hole-ICL", was created. The monofocal IOL, which was used as an artificial crystalline lens, was +30.0 D in power, and it was 13.0 mm in length with an optic diameter of 6.0 mm. The line-spread function (LSF) was recorded with the OPAL Vector System (Image Science Ltd.), and a model eye (Menicon Co.) was used that consisted of a wet cell. A conventional ICL or Hole-ICL was placed in the posterior chamber of the model eye. The MTF was calculated from the LSF using fast Fourier transform techniques. Furthermore, we investigated the relationship between pupil size and the MTF of the ICL for -5.0 D. The sizes of the effective aperture were 2.0, 3.0, 4.0, and 5.0 mm.

RESULTS

The in-focus contrasts of the conventional ICL at 100 cyc/mm for a 3.0-mm effective aperture were 37%, 40%, 39%, 38%, and 39% for -20.0 D, -10.0 D, -5.0 D, +3.0 D, and +10.0 D respectively. The in-focus contrasts of the Hole-ICL at 100 cyc/mm for a 3.0-mm effective aperture were 37%, 40%, 39%, 38%, and 38% for -20.0 D, -10.0 D, -5.0 D, +3.0 D, and +10.0 D respectively. The results for a 2.0-mm effective diameter showed that the in-focus MTF in the Hole-ICL was lower than in the conventional ICL, although the difference was small.

CONCLUSION

These results suggest that differences in MTF between the Hole-ICL and the conventional ICL for various ICL powers and effective pupil diameters were small and clinically negligible.

Repeatability and reproducibility of anterior ocular biometric measurements with 2-dimensional and 3-dimensional optical coherence tomography

PURPOSE

To evaluate the repeatability and reproducibility of central corneal thickness (CCT), anterior chamber depth (ACD), and anterior chamber width (ACW) measurements using 3-dimensional (3-D) corneal and anterior segment optical coherence tomography (CAS-OCT) and 2-dimensional (2-D) anterior segment OCT (AS-OCT).

SETTING

Department of Ophthalmology, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan.

DESIGN

Nonrandomized clinical trial.

METHODS

The CCT, ACD, and ACW were measured in normal eyes using a prototype 3-D swept-source CAS-OCT device and a 2-D time-domain AS-OCT device (Visante). The coefficient of repeatability and reproducibility and the intraclass correlation coefficient (ICC) were calculated to evaluate the repeatability and reproducibility of the measurements.

RESULTS

Eighty-five eyes (85 subjects) were evaluated. The mean CCT measurement was 557.5 μm ± 40.5 (SD) with CAS-OCT and 556.4 ± 39.4 μm with AS-OCT; the mean ACD measurement, 3.13 ± 0.40 mm and 3.16 ± 0.39 mm, respectively; and the mean ACW, 11.80 ± 0.47 mm and 11.79 ± 0.49 mm, respectively. There was no statistically significant difference in CCT or ACW measurements between the 2 devices (P>.05, Wilcoxon signed rank test). Although the ACD measurements were significantly different (P<.0001), the difference was small (0.03 mm). Significant linear correlations were found between the measurements of the 2 devices (P<.0001). The ICC was greater than 0.99 for CAS-OCT and greater than 0.96 for AS-OCT.

CONCLUSION

Corneal and anterior segment OCT and AS-OCT provided comparable and well-correlated anterior ocular biometric measurements, with sufficient repeatability and reproducibility.

Refractive stability of LASIK with the Visx 20/20 excimer laser vs ZB5m phakic iol implantation in patients with high myopia (>-10.00 d): a 10-year retrospective study

PURPOSE

To compare the long-term outcomes of LASIK and ZB5M phakic intraocular lens implantation (PIOL) (Domilens) for high myopia (>-10.00 diopters [D]).

METHODS

This long-term (10 years) follow-up retrospective interventional case series study included 126 eyes that underwent LASIK and 52 eyes that underwent ZB5M angle-supported PIOL implantation. Both groups of eyes were similar in terms of preoperative spherical equivalent refraction (SE), corrected distance visual acuity (CDVA), and age.

RESULTS

Mean preoperative SE was -14.33 D in the LASIK group and -14.84 D in the PIOL group. At 10-year follow-up, mean postoperative SE was -1.47±2.00 D in the LASIK group and -1.01±1.36 D in the PIOL group (P=.21). In the LASIK group, 67% of eyes were within ±1.00 D of emmetropia at 2 years after surgery, compared to 42% at 10 years. In the PIOL group, 68% of eyes were within ±1.00 D of emmetropia 2 years after implantation compared to 53% at 10 years. In the LASIK group, 43.5% of eyes achieved UDVA of 20/40 or better 10 years after surgery compared to 67.9% in the PIOL group (P=.02).

CONCLUSIONS

The ZB5M angle-supported PIOL was shown to have better predictability and stability compared to LASIK over 10 years. However, reductions in endothelial cell count over time were observed in eyes with PIOLs.

Comparison of clear lens extraction and collamer lens implantation in high myopia

Aim:

To compare the outcomes of clear lens extraction and collamer lens implantation in high myopia.

Patients and methods:

Myopic patients younger than 40 years old with more than 12 diopters of myopia or who were not fit for laser-assisted in situ keratomileusis were included. Group 1 comprised patients undergoing clear lens extraction and Group 2 patients received the Visian implantable collamer lens. Outcome and complications were evaluated.

Results:

Postoperative best corrected visual acuity was −0.61 ± 0.18 in Group 1 and 0.79 ± 0.16 in Group 2. In Group 1, 71.4% achieved a postoperative uncorrected visual acuity better than the preoperative best corrected visual acuity, while only 51.8% patients achieved this in Group 2. Intraocular pressure decreased by 12.55% in Group 1, and increased by 15.11% in Group 2. Corneal endothelial cell density decreased by 4.47% in Group 1 and decreased by 5.67% in Group 2. Posterior capsule opacification occurred in Group 1. In Group 2, lens opacification occurred in 11.11%, significant pigment dispersion in 3.7%, and pupillary block glaucoma in 3.7%.

Conclusion:

Clear lens extraction presents less of a financial load up front, and less likelihood of the need for a secondary intervention in the future. Clear lens extraction is a more viable solution in developing countries with limited financial resources.

Iridocyclitis associated with angle-supported phakic intraocular lenses

PURPOSE

To evaluate incidence, features, risk factors, and prognosis of iridocyclitis after angle-supported phakic intraocular lens (IOL) implantation.

SETTING

Private practice, Siena, Italy.

METHODS

This retrospective analysis comprised 356 consecutive eyes of 212 patients. In myopic eyes, the ZSAL-4 IOL (205 eyes of 125 patients) or the ZSAL-4 Plus IOL (106 eyes of 63 patients) was used. In hyperopic eyes (45 eyes of 24 patients), the Type 54 IOL was implanted. Haptic posterior angulation was 19 degrees (ZSAL-4), 23 degrees (ZSAL-4 Plus), and 14 degrees (Type 54).

RESULTS

Clinically significant iridocyclitis occurred in 11 eyes (3.1%) of 11 patients. Mean patient age was 37.3 years +/- 9.4 (SD). Sixty-four percent were male (odds ratio [OR], 3.0; 95% confidence interval [CI], 0.8 to 7.4, not statistically significant). Iridocyclitis was observed in 4.4% of hyperopic eyes (OR, 1.6; 95% CI, 0.3 to 7.4; not statistically significant) and in 2.9% of myopic eyes. In myopic eyes, it followed the implantation of ZSAL-4 IOL in 3.9% of eyes (OR, 4.1; 95% CI, 0.5 to 33.6; not statistically significant), and of ZSAL-4 Plus IOL in 1%. Mean time from surgery was 8.5 +/- 10.6 months). Presentation included aqueous flare (100%), posterior synechiae (82%), blurred vision (82%), redness (36%), pain (27%), IOL precipitates (18%), and angular synechiae (9%). Only 1 patient had recurrences, leading to IOL explantation and cataract surgery. After topical therapy, best spectacle-corrected visual acuity was fully recovered in 9 of 11 eyes.

CONCLUSION

Iridocyclitis can occur months or years after the implantation of angle-supported phakic IOLs. No statistically significant risk factors were identified. Functional prognosis is generally good.

Corneal edema and penetrating keratoplasty after anterior chamber phakic intraocular lens implantation

Phakic intraocular lens (IOL) implantation is an increasingly popular option in surgical correction of refractive error. To date, reports of long-term morbidity are infrequent in the literature. We encountered 3 patients who experienced corneal decompensation and cataract progression following angle-fixated anterior chamber phakic IOL placement.

Phakic Intraocular Lenses

An analytical review of the data available in the field of phakic intraocular lens implantation was conducted. Particular attention was paid to the more critical issues of intraocular lens sizing and safety guidelines. A comprehensive, competitive analysis of different implantation sites, intraocular lens model designs, and safety guidelines has been included. Specialized biometry techniques, such as very high frequency ultrasound and Scheimpflug imaging, have been reviewed, and a critical review of commercial claims regarding intraocular lens technologies has been included. Clinical studies of phakic intraocular lenses demonstrate increasing promise for the correction of refractive errors not amenable to mainstream excimer laser refractive surgery. The main issues currently revolve around adequate lens design (VHF ultrasound study suggests that custom-design and sizing may be the most effective and safest approach for every phakic IOL model), because these devices will be required to remain physiologically inert and anatomically compatible with internal ocular structures and relations for several decades. The possibility of safe removing or exchanging the IOL should remain a feasible option over time. It is of utmost importance that we continue to critically evaluate current encouraging short-term outcomes, which are being extrapolated to the longer term by ongoing high resolution imaging and monitoring of the anatomical and functional relations of implanted phakic IOLs.

Intraokularlinsen zur Korrektur von Refraktionsfehlern

In this overview, the current status of intraocular lens surgery to correct refractive error is reviewed. The interventions are divided into additive surgery with intraocular lens implantation without extraction of the crystalline lens (phakic intraocular lens, PIOL) or removal of the crystalline lens with implantation of an IOL (refractive lens exchange, RLE). Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and posterior chamber lenses which are fixated in the ciliary sulcus. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and differ for the three types of PIOL; for posterior chamber lenses these are mainly cataract formation and pigment dispersion. RLE is preferable in cases of high ametropia in which the natural lens has lost its accommodative effect. The main complications for myopic RLA include retinal detachment, while hyperopic refractive lens exchange may be associated with surgical problems in the narrower anterior eye segment.

Intraokularlinsen zur Korrektur von Refraktionsfehlern

In this overview, the current status of intraocular lens surgery to correct refractive error is reviewed. The interventions are divided into additive surgery with intraocular lens implantation without extraction of the crystalline lens (phakic intraocular lens, PIOL) or the removal of the crystalline lens with implantation of an IOL (refractive lens exchange, RLE). Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and posterior chamber lenses that are fixated in the ciliary sulcus. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and differ for the three types of PIOL; for anterior chamber lenses these are mainly pupil ovalization and endothelial cell loss.

Refractive lens exchange for myopia: a new perspective?

PURPOSE OF REVIEW

Although lens surgery for high myopia has a long History, it has been extremely controversial. Colin's study of 1999 indicated a much higher than expected rate of retinal detachment. The purpose of this review is to reassess the place of refractive lens exchange in high myopia in the light of more recent reports in the literature and a more critical examination of Colin's data.

RECENT FINDINGS

A meta analysis of papers on refractive lens exchange and cataract in high myopia between 1996 and 2004 included some 2036 eyes. The mean follow up was 43.5 months and overall incidence of retinal detachment was 1.85%. This is only slightly different from that expected in the highly myopic population as reported by Burton at 1.5%. The recent reports in 2003 of Ravalico et al. and Guell et al., with 4 year follow up, show only 1 detachment for 422 eyes. Further Colin's study had a group very high in risk factors having a low incidence of posterior detachment and 30% pre-existing retinal lesions.

SUMMARY

Modern surgical techniques, IOLs and choosing the appropriate group to whom this procedure should be offered should lead to it becoming an accepted, safe and common refractive operation.

Contact entre le cristallin naturel et différents modèles d’implants réfractifs phakes. Étude avec l’OCT de chambre antérieure

Three patients received three different models of phakic implants. With the usual slit-lamp examination method, we were not able to establish whether there was contact between the implants and the natural crystalline lens. Using the anterior chamber optical coherence tomography scanner (AC-OCT), we were able to demonstrate that there was direct contact between the natural crystalline lens and the three different phakic implants. A dynamic study of these contacts was carried out during accommodation. These observations show that examination of the anterior segment with the optical coherence tomography scanner is essential in refractive surgery.

Anterior chamber width measurement by high-speed optical coherence tomography

OBJECTIVE

To measure anterior chamber (AC) width and other dimensions relevant to the sizing of phakic intraocular lenses (IOLs) with a high-speed optical coherence tomography (OCT) system.

DESIGN

Cross-sectional observational study.

PARTICIPANTS

Both eyes of 20 normal volunteers.

METHODS

A novel high-speed (4000 axial scans/second) OCT prototype was developed for anterior segment scanning. The system uses long wavelength (1310 nm) for deeper angle penetration, rectangular scanning for undistorted imaging, and short image acquisition time (0.125 seconds) to reduce motion error. Three horizontal cross-sectional OCT images (15.5 mm wide and 6 mm deep) of the anterior segment were obtained from each eye with real-time image display to guide centration on the corneal apex. Image processing software was developed to correct for image warping resulting from index transitions. Anterior chamber dimensions were measured using computer calipers by 3 expert raters (ophthalmologists). Analysis of variance was used to determine interrater, interimage, right versus left eye, and intersubject standard deviation (SD) of OCT measurements.

MAIN OUTCOME MEASURES

Anterior chamber width (recess to recess), AC depth, and crystalline lens vault as measured by OCT; external white-to-white (WTW) corneal diameter (CD) as measured by Holladay-Godwin gauge.

RESULTS

The mean AC width was 12.53+/-0.47 mm (intereye SD), and the mean corneal diameter was 11.78+/-0.57 mm. Optical coherence tomography measurement of AC width has good repeatability from image to image (SD, 0.134 mm), but there was significant difference between raters (SD, 0.215 mm). Estimation of AC width from WTW CD by linear regression was relatively inaccurate (residual SD, 0.41 mm). The mean AC depth was 2.99+/-0.323 mm (intereye SD), with repeatability of less than 0.001 mm (interimage SD), and the mean crystalline lens vault was 0.39+/-0.27 mm with 0.023 mm repeatability.

CONCLUSIONS

Reproducible OCT AC biometry was demonstrated using a high-speed OCT prototype. Further improvement in reproducibility may be achieved by automating the measurements with a computer. Direct OCT AC width measurement may improve sizing of angle-supported AC IOLs over conventional estimation by WTW CD. The measurement of AC depth and lens vault also may be useful for other types of phakic AC IOLs.

INTACS Before or After Laser in situ Keratomileusis: Correction of Thin Corneas With Moderately High Myopia

PURPOSE

Intrastromal corneal ring segments (INTACS Micro-Thin Prescription Inserts by Addition Technologies, Fremont, Calif) were inserted as a combined surgery with laser in situ keratomileusis (LASIK) in six eyes with thin corneas to correct moderately high myopia.

METHODS

INTACS were implanted before LASIK (INTACS-LASIK) in three eyes and after LASIK (LASIK-INTACS) in three eyes. Mean preoperative manifest spherical equivalent refraction was -7.88 diopters. Mean follow-up was 306 days.

RESULTS

No intraoperative complications occurred. The LASIK-INTACS eyes were slightly more overcorrected than the INTACS-LASIK eyes because of the enhanced performance of INTACS in the thinned corneal tissue. Induced astigmatism by INTACS per se was less in the LASIK-INTACS eyes than in the INTACS-LASIK eyes. At last examination, uncorrected visual acuity was better than 20/25 in all eyes. Best spectacle-corrected visual acuity was within 1 line of the preoperative value in all eyes.

CONCLUSION

Both methods resulted in significant improvement in visual acuity and refraction. Based on our limited experience, however, LASIK followed by INTACS is preferred for reasons of safety, convenience, and lower induced cylinder.

Phakic intraocular lens implantation versus clear lens extraction in highly myopic eyes of 30- to 50-year-old patients

PURPOSE

To compare the outcome of treatment for myopia by phakic intraocular lens (IOL) implantation or by clear lens extraction (CLE).

SETTING

Service d'Ophtalmologie, Hopital Purpan, Toulouse, France.

METHODS

Thirty-nine patients from 32 to 49 years of age were studied. Forty-one eyes of 21 patients received a phakic IOL, and 36 eyes of 18 patients had phacoemulsification of the crystalline lens. The mean preoperative spherical equivalent (SE) was -13.6 diopters (D) +/- 3.0 (SD) in the phakic IOL group and -16.7 +/- 3.8 D in the CLE group.

RESULTS

Postoperatively, the mean SE was -1.06 +/- 0.78 D in the IOL group and -1.88 +/- 0.83 D in the CLE group. At 12 months, the best corrected visual acuity (BCVA) had improved in 78.0% of eyes in the IOL group and 83.3% in the CLE group; no eye lost 1 line of BCVA. In 3 eyes (7.31%) in the IOL group, opacification of the crystalline lens developed 34, 36, and 44 months after implantation. Visual recovery after phacoemulsification was excellent. No eye in this group lost 1 or more lines of BCVA between 1 and 4 years of the initial surgery. In the CLE group, a retinal detachment occurred in 2 eyes at 39 and 43 months. The final BCVA in these eyes was counting fingers and 20/200.

CONCLUSION

Implantation of a phakic IOL in a highly myopic eye of a patient between 30 and 50 years of age can be considered an adequate technique with a lower risk for loss of BCVA than CLE.

Contact between 3 phakic intraocular lens models and the crystalline lens: An anterior chamber optical coherence tomography study

Three phakic intraocular lens (IOL) models were implanted in 3 different patients. With the usual slitlamp examination, it was not possible to determine whether there was contact between the IOLs and the natural crystalline lens. Using the anterior chamber optical coherence tomography (AC OCT) scanner, direct contact between the natural crystalline lens and the 3 phakic IOLs was revealed. A dynamic study of the contact was performed during accommodation. These observations show that examination of the anterior segment with the AC OCT scanner provides new data about the status of the anterior segment after implantation of phakic IOLs.

The Duet-Kelman Lens: A New Exchangeable Angle-supported Phakic Intraocular Lens

PURPOSE

We describe a new model of angle-supported phakic intraocular lens, the Duet-Kelman lens, the design of which incorporates two separate supporting parts. The haptic and the optic are separately implanted and then fixed together inside the eye. The lens allows optic or haptic exchange depending on the anatomical, refractive, and visual outcome of the patient. Results of the initial pilot study are presented.

METHODS

Three patients (three eyes) were implanted with the Duet-Kelman lens and were followed for a minimum of 6 months. Surgery was performed under topical anesthesia.

RESULTS

Surgery was feasible through a 2.5-mm incision, without complications. Refractive and visual results were stable in all eyes. Haptic exchange was done in one eye that developed pupil ovalization.

CONCLUSION

In this pilot study of three eyes, the Duet-Kelman phakic intraocular lens offered small incision size and potential exchange of the haptic or the optic.

Incidence of Lens Opacities and Clinically Significant Cataracts With the Implantable Contact Lens: Comparison of Two Lens Designs

PURPOSE

To compare the incidence of anterior subcapsular lens opacities, clinically significant cataracts, secondary lens-related surgical reinterventions, and vaulting characteristics of the now discontinued V3 and currently used V4 Staar Surgical Implantable Contact Lens (ICL) phakic intraocular lens designs.

METHODS

In this non-randomized prospective clinical trial, 87 eyes were implanted with the V3 and 523 eyes with the V4 ICL as part of the U.S. FDA clinical trial for myopia. LOCS III assessment of lens opacities, clinically significant cataract, ICL vaulting (clearance between ICL and crystalline lens), and secondary ICL-related surgeries were the main outcome measures. Mean follow-up in the V3 series was 30.7 +/- 10.0 months (range 10.8 to 49.3 mo) and in the V4 series, 17.3 +/- 6.9 months (range 0.25 to 38.5 mo).

RESULTS

Incidence of anterior subcapsular opacities was significantly higher with the V3 vs. V4 ICL (12.6% vs. 2.9%, P<.001). The difference was largely due to the higher rate of late-appearing opacities (> or = 1 year after surgery; 9.2% vs. 0.6%, P<.001). The V3 group had a greater proportion of eyes with poor vault (23.6% vs. 4.3%, P<.001) and the presence of poor vault was highly associated with the development of late anterior subcapsular opacities (P<.001). Clinically significant cataract was more frequent in the V3 vs. V4 ICL (9.2% vs. 0.8%, P<.001), as was cataract extraction (6.9% vs. 0.2%, P<.001), and need for ICL replacement (5.7% vs. 1.1%, P<.001). Differences in opacity rate between the V3 and V4 designs were not due to differences in postoperative follow-up.

CONCLUSION

Implantation of the currently used V4 Staar Surgical model ICL resulted in significantly less anterior subcapsular opacities, clinically significant cataracts, and secondary ICL-related surgery.

Phakic intraocular lenses

Since Zaldivar's review of phakic intraocular lenses in these pages in 2000 [1**], further reports of experience with this technology have emerged. Their relative advantages and disadvantages over competing technologies are becoming clearer. Clinical trials, including Food & Drug Administration (FDA) trials, have shown predictability, stability, and efficacy. Safety of these implants over the long term remains a concern, but in some situations, at least, phakic intraocular lenses are becoming the refractive correction of choice. This brief review looks at the most recent data to emerge regarding phakic intraocular lenses.

Vitreous hemorrhage following phakic anterior chamber intraocular lens implantation in severe myopia

PURPOSE

To describe two cases of vitreous hemorrhage following phakic anterior chamber lens (AC-IOL) implantation in high myopia.

CASE REPORT

In case 1, hemorrhage developed one month after surgery, without retinal involvement, and visual acuity (VA) resulted 20/200 after pars-plana vitrectomy (PPV). In Case 2, vitreous hemorrhage was complicated by retinal detachment (RD). PPV and silicone oil injection were performed, with AC-IOL removal and cristalline lens extraction. After 2 years the retina was attached and VA was 20/80.

DISCUSSION

Only few cases of RD, posterior uveitis and endophthalmitis are reported following phakic AC-IOL implant. Vitreous hemorrhage could represent an additional posterior segment complication. Intraoperative manoeuvres, hypotony-induced posterior vitreous detachment and/or peripheral retina traction could play a role in engendering this complication in highly myopic eyes.