Phakic intraocular lenses

Evaluation of the agreement of optical biometry and Scheimpflug corneal topography with different axial lengths

PURPOSE

To compare anterior segment parameters evaluated with optical low coherence reflectometry and combined Scheimpflug-Placido disc topography in eyes with different axial lengths.

METHODS

Deux cent quatre patients were divided into 3 groups according to their axial lengths. Central corneal thickness (CCT), anterior chamber depth (AD), mean keratometry value (K mean) and white-to-white distances (WTW) obtained from both devices were compared. All measurements were performed 3 times and averaged.

RESULTS

In group 1, a significant difference was detected between the two devices for CCT, WTW and Kmean measurements (P<0.001, P<0.001, p:0.005 respectively). In group 2, a significant difference was detected between the two devices for WTW measurement (P<0.001). In group 3, a significant difference was detected between the two devices for CCT and WTW measurement (P<0.001, P<0.001 respectively). In the Bland-Altman analysis, there was no match for Kmean obtained with both devices in group 1. In group 2, there was no agreement for AD obtained with both devices. In group 3, there was no match for AD, WTW or Kmean values obtained with both devices.

CONCLUSION

Some anterior segment parameters are not suitable for interchangeability in eyes with different axial lengths evaluated by Lenstar and Sirius anterior segment imaging systems. When planning critical surgery and treatment, more attention should be paid to measurements in eyes of different axial lengths.

A Novel Concept of Correcting Presbyopia: First Clinical Results with a Phakic Diffractive Intraocular Lens

Purpose

To evaluate the effect of a novel technique to correct presbyopia. A phakic IOL (presbyopic IPCL; implantable phakic contact lens) with a diffractive optic is implanted and its impact on visual acuity, refraction, patient satisfaction in patients striving for spectacle-independence is evaluated.

Design

Retrospective noncomparative open-label clinical trial.

Methods

Sixteen eyes of 8 patients (average age 47 years) had a presbyopic IPCL implanted in the posterior chamber. The visual acuity on different distances, refractive status, corneal topography, endothelial cell density, anterior chamber depth, white-to-white, mesopic pupil size and intraocular pressure (IOP) were measured before implantation of this novel phakic IOL with diffractive optic and four weeks after surgery.

Results

At follow-up four weeks after surgery, 9 of the 16 eyes were emmetropic and uncorrected distance visual acuity was at least 0.8. Near vision was excellent in all patients without the need to wear reading glasses. There was neither a significant change in IOP nor a significant surgical impact on endothelial cells. Patient satisfaction was high. There was no major complaint of halos or glare.

Conclusion

The presbyopic IPCL can provide the presbyopic patient with good visual acuity and spectacle-independence for far and near distance. We found this novel technique to have a good safety profile during the surgical procedure and our short follow-up period. Further long-term follow-up is mandatory.

The effect of light and outdoor activity in natural lighting on the progression of myopia in children

PURPOSE

To investigate potential risk factors for the progression of myopia.

METHODS

Prospective study. Myopic progression was evaluated by cycloplegic autorefraction and axial length (AL) every 6 months in children 6 to 15 years old. Univariate analysis and multiple logistic regression were applied.

RESULTS

Around 82 children with median age of 10.3±2.3 years. Myopia progressed by -0.816±0.6 D over 18 months. Increased myopic spherical equivalent refraction (SER) was correlated with increase in AL (P<0.001). Univariate analysis found SER to be significantly associated with: age, especially between 6 and 9.4 years old (P=0.001), parental myopia (P=0.028), and less time spent outdoors (P=0.009). There was a significantly greater increase in SER during months with the least daylight hours (P<0.001).

CONCLUSION

Outdoor activities and daylight have a protective effect against increased AL and progression of myopia. Younger children with significant myopia should be monitored closely, especially those around 6 years old with myopic parents.

Short and long-term outcomes of angle supported phakic intraocular lens implantation in high myopic eyes

This cohort study included 36 eyes of 21 patients with high myopia treated with angle supported phakic intraocular lens (pIOL). Endothelial cell density (ECD) at baseline, 6mo and 3y were 3017±296, 2775±265 and 2558±299 cells/mm2 respectively. ECD loss at 6mo was 7.2% and annual ECD loss was 3% over 36mo. Corrected distance visual acuity at 36mo was 0.4 logMAR or better in 32 (88.9%) eyes. Intraocular pressure did not change (P=0.9). No eyes developed cataract, retinal detachment or pupillary distortion. Angle supported pIOL gives good visual outcome. Endothelial cell loss should be monitored.

Comparison of Implantable Collamer Lens Visian ICL V4 and ICL V4c for high myopia: A cohort study

The aim of this study was to investigate the visual quality of the 2 kinds of intraocular lens: Visian implantable collamer lens (ICL) V4 and Visian ICL V4c implantations for high myopia.Twenty cases (20 eyes) with high myopia who received Visian ICL V4 implantation and 18 cases (18 eyes) with high myopia who received Visian ICL V4c implantation in our hospital from April 1, 2014 to November 31, 2016 were enrolled. In 1-month follow-up, near vision, best corrected distant visual acuity (BCVA), uncorrected distant visual acuity (UDVA), and wavefront aberrations were measured, and compensation factor was calculated.Near vision, UDVA, and BCVA showed no significant difference between ICL V4 implantation and ICL V4c implantation (P >.05). However, high-order aberrations and spherical aberrations were higher in ICL V4c implantation than in ICL V4 implantation (P <.05). Low-order aberrations (defocus and astigmatism), coma, and subjective visual quality had no significant difference between ICL V4 implantation and ICL V4c implantation (P >.05).The 2 kinds of ICL Visian ICL V4 and Visian ICL V4c had similar efficacy of visual quality for high myopia. The presence of the central hole of Visian ICL V4c has no significant effect on visual quality.

Comparison of keratometry and white-to-white measurements obtained by Lenstar with those obtained by autokeratometry and corneal topography

PURPOSE

To compare anterior eye segment measurements obtained using low optical coherence reflectometry (LENSTAR LS900, Haag-Streit), autokeratometry (RC-5000, Tomey) and corneal topography (Topolyzer, Wavelight).

METHODS

In 46 healthy subjects, flat keratometry (Kf), steep keratometry (Ks), mean keratometry (Km) and white-to-white (WTW) distance were measured by Lenstar, Tomey RC-5000 and Topolyzer.

RESULTS

Kf and Km measurements of Lenstar were significantly steeper than Tomey RC-5000 (both p<0.001), but the 95% LoA of them were narrow (-0.22 to 0.46D, -0.16 to 0.36D, respectively). There were no significant differences between the Kf and Km measurements of Lenstar and Topolyzer, with a narrow 95% LoA. There were no significant differences between the Ks measurements of Lenstar and Tomey RC-5000, and Lenstar and Topolyzer. A good agreement was found between them with 95% LoA of -0.40 to 0.56D, and -0.56 to 0.64D, respectively. WTW measurements with Lenstar were greater than those with Tomey RC-5000 and Topolyzer (p=0.042, p<0.01, respectively). A good agreement existed between the WTW obtained by Lenstar and Topolyzer, Tomey RC-5000, with 95% LoA ranging from -0.13 to 0.74mm and -0.33 to 0.51mm.

CONCLUSIONS

Generally good agreement was found between the Lenstar and Tomey RC-5000, Topolyzer for K and WTW measurements. In clinical practice, K and WTW measurements obtained by Lenstar and Tomey RC-5000, Topolyzer can be used interchangeably.

Posterior sclera reinforcement and phakic intraocular lens implantation for highly myopic amblyopia in children: a 3-year follow-up

PURPOSE

To study the safety and efficacy of posterior scleral reinforcement (PSR) combined with phakic intraocular lens (PIOLs) implantation for highly myopic amblyopia in children.

METHODS

This study included eight highly myopic children (11 eyes) who failed in conventional therapy for amblyopia using various combination of spectacles, contact lenses, and intensive patching before enrollment into this study. They were treated sequentially with PSR and PIOL implantation, and were followed up for 3 years after surgery. Uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) in LogMAR, spherical equivalent power (SE), and complications were evaluated.

RESULTS

Before surgery, the mean UCVA was 1.59±0.33, BCVA, 0.74±0.37, SE, -17.57±5.56D, the axial length (AL), 30.09±2.18 mm. After PSR, BCVA improved one line in three patients, the rest were unchanged, and AL was unchanged among all cases. Six eyes of three patients were implanted with an iris-claw PIOL and five eyes of five patients were implanted with a posterior PIOL. After completion of treatment, the mean UCVA was 0.44±0.21, BCVA 0.38±0.24, SE -0.54±0.74 D, and AL 30.35±2.29 mm. No patient experienced complications.

CONCLUSION

Combined PSR and PIOL implantation treatment for highly myopic amblyopia in children is safe and effective.

Excimer laser refractive surgery versus phakic intraocular lenses for the correction of moderate to high myopia

BACKGROUND

Myopia is a condition in which the focusing power (refraction) of the eye is greater than that required for clear distance vision. There are two main types of surgical correction for moderate to high myopia; excimer laser and phakic intraocular lenses (IOLs). Excimer laser refractive surgery for myopia works by removing corneal stroma to lessen the refractive power of the cornea and to bring the image of a viewed object into focus onto the retina rather than in front of it. Phakic IOLs for the treatment of myopia work by diverging light rays so that the image of a viewed object is brought into focus onto the retina rather than in front of the retina. They can be placed either in the anterior chamber of the eye in front of the iris or in the posterior chamber of the eye between the iris and the natural lens.

OBJECTIVES

To compare excimer laser refractive surgery and phakic IOLs for the correction of moderate to high myopia by evaluating postoperative uncorrected visual acuity, refractive outcome, potential loss of best spectacle corrected visual acuity (BSCVA) and the incidence of adverse outcomes.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 1), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to February 2014), EMBASE (January 1980 to February 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 11 February 2014.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing excimer laser refractive surgery and phakic IOLs for the correction of myopia greater than 6.0 diopters (D) spherical equivalent.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We performed data analysis. We summarised data for outcomes using odds ratios. We used a fixed-effect model as only three trials were included in the review.

MAIN RESULTS

This review included three RCTs with a total of 228 eyes. The range of myopia of included patients was -6.0 D to -20.0 D of myopia with up to 4.0 D of myopic astigmatism. The percentage of eyes with uncorrected visual acuity (UCVA) of 20/20 or better at 12 months postoperative was not significantly different between the two groups. Phakic IOL surgery was safer than excimer laser surgical correction for moderate to high myopia as it results in significantly less loss of best spectacle corrected visual acuity (BSCVA) at 12 months postoperatively. However there is a low risk of developing early cataract with phakic IOLs. Phakic IOL surgery appears to result in better contrast sensitivity than excimer laser correction for moderate to high myopia. Phakic IOL surgery also scored more highly on patient satisfaction/preference questionnaires.

AUTHORS' CONCLUSIONS

The results of this review suggest that, at one year post surgery, phakic IOLs are safer than excimer laser surgical correction for moderate to high myopia in the range of -6.0 to -20.0 D and phakic IOLs are preferred by patients. While phakic IOLs might be accepted clinical practice for higher levels of myopia (greater than or equal to 7.0 D of myopic spherical equivalent with or without astigmatism), it may be worth considering phakic IOL treatment over excimer laser correction for more moderate levels of myopia (less than or equal to 7.0 D of myopic spherical equivalent with or without astigmatism). Further RCTs adequately powered for subgroup analysis are necessary to further elucidate the ideal range of myopia for phakic IOLs. This data should be considered alongside comparative data addressing long-term safety as it emerges.

Stability of cachet phakic intraocular lens position during 6-months follow-up

Purpose:

To evaluate the position stability of a phakic intraocular lens (Cachet pIOL; Alcon, Laboratories, Inc., Fort Worth, TX) in the anterior chamber (AC) during a 6-months follow-up.

Methods:

Thirty eyes of 16 subjects underwent a Cachet pIOL implantation for the correction of high myopia from -6.50 to -16.00 D with plano targeted refraction. The position stability of the Cachet pIOL was evaluated using an Anterior Segment-OCT (AS-OCT, Carl Zeiss AG, Oberkochen, Germany) at 1- and 6-months postoperatively. Three measurements have been taken into account: 1) the minimum distance between the anterior surface of the Cachet pIOL optic disk and the central corneal endothelium; 2) the minimum distance between the optic disk’s edges of the pIOL and the endothelium; 3) the minimum distance between the posterior surface of the pIOL optic disk and the anterior surface of the crystalline lens. The endothelial cell density (ECD) was also recorded.

Results:

No statistically significant changes of the Cachet pIOL position in the AC were found during follow-up. The average changes were ≤0.1 mm between 1- and 6-months postoperatively (P>0.05). At the end of follow-up, The mean ECD loss was 0.7 % (from 2794 ± 337 cell/mm² to 2776 ± 388 cell/mm²; P>0.05).

Conclusion:

A high position stability of the Cachet pIOL in the anterior chamber was shown during a 6-months follow-up.

Retinal detachment after phakic intraocular lens implantation in severe myopic eyes

BACKGROUND

To report the incidence, clinical presentation, and surgical outcomes of retinal detachment in highly myopic patients corrected by implantation of phakic intraocular lenses (PIOLs).

METHODS

This is a retrospective interventional non-comparative case series. A total of 530 highly myopic eyes that underwent PIOLs implantation were included in the study. All patients completed at least a 2-year follow-up after PIOL implantation. The incidence of retinal detachment (RD) and subsequent treatments were reviewed. The refractive errors, axial lengths, time between refractive surgery and RD detection, vitreoretinal findings, rate of retinal reattachment, and the pre- and postoperative best-corrected visual acuity (BCVA) were analyzed.

RESULTS

The overall incidence of RD was 1.5 % (eight eyes of seven patients) with a mean time between PIOL implantation and detachment of 23.63 ± 18.12 months (range, 2 days-51 months). Mean spherical equivalent (SE) before PIOL implantation was -17.53 ± 3.86 diopters (D) (range, -11.5D to -23.5D). Six patients underwent bilateral PIOL implantation. Five eyes were implanted with anterior chamber PIOLs and the other three received posterior chamber PIOLs. A traumatic history was presented before RD detection in four cases. Horseshoe tears, atrophic holes, or giant retinal tears were found in four (50 %), two (25 %), and two (25 %) eyes, respectively. Two eyes (25 %) underwent scleral buckling surgery, five eyes (62.5 %) underwent pars plana vitrectomy surgery, and one eye (12.5 %) underwent both procedures. Anatomical retinal attachment was achieved after first RD surgery in seven eyes. Mean BCVA after PIOL implantation and before RD was 20/40 (decimal refraction, 0.51 ± 0.31) compared to that of 20/80 (decimal refraction, 0.26 ± 0.12) after the RD surgery. Mean follow-up after RD surgery was 20.63 ± 12.93 months (range, 8-42 months).

CONCLUSIONS

The incidence of RD after PIOLs implantation is low. Its characteristics do not differ significantly from the natural history of RD in high myopic eyes. PIOL implantation for surgical correction of severe myopia does not seem to increase the risk of RD. Good visual prognosis can be obtained with early surgical intervention.

Excimer laser refractive surgery versus phakic intraocular lenses for the correction of moderate to high myopia

BACKGROUND

Myopia is a condition in which the focusing power (refraction) of the eye is greater than that required for clear distance vision. There are two main types of surgical correction for moderate to high myopia; excimer laser and phakic intraocular lenses (IOLs). Excimer laser refractive surgery for myopia works by removing corneal stroma to lessen the refractive power of the cornea and to bring the image of a viewed object into focus onto the retina rather than in front of it. Phakic IOLs for the treatment of myopia work by diverging light rays so that the image of a viewed object is brought into focus onto the retina rather than in front of the retina. They can be placed either in the anterior chamber of the eye in front of the iris or in the posterior chamber of the eye between the iris and the natural lens.

OBJECTIVES

The aim of this review is to compare the effect of excimer laser refractive surgery versus phakic IOLs for the correction of moderate to high myopia.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 11), MEDLINE (January 1950 to November 2011), EMBASE (January 1980 to November 2011), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to November 2011), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 28 November 2011.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing excimer laser refractive surgery and phakic IOLs for the correction of myopia greater than 6.0 diopters (D) spherical equivalent.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We performed data analysis. We summarised data for outcomes using odds ratios. We used a fixed-effect model as only three trials were included in the review.

MAIN RESULTS

This review included three RCTs with a total of 228 eyes. The range of myopia of included patients was -6.0 D to -20.0 D of myopia with up to 4.0 D of myopic astigmatism. The percentage of eyes with uncorrected visual acuity (UCVA) of 20/20 or better at 12 months postoperative was not significantly different between the two groups. Phakic IOL surgery was safer than excimer laser surgical correction for moderate to high myopia as it results in significantly less loss of best spectacle corrected visual acuity (BSCVA) at 12 months postoperatively. However there is a low risk of developing early cataract with phakic IOLs. Phakic IOL surgery appears to result in better contrast sensitivity than excimer laser correction for moderate to high myopia. Phakic IOL surgery also scored more highly on patient satisfaction/preference questionnaires.

AUTHORS' CONCLUSIONS

The results of this review suggest that phakic IOLs are safer than excimer laser surgical correction for moderate to high myopia in the range of -6.0 to -20.0 D and phakic IOLs are preferred by patients. While phakic IOLs might be accepted clinical practice for higher levels of myopia (greater than or equal to 7.0 D of myopic spherical equivalent with or without astigmatism), it may be worth considering phakic IOL treatment over excimer laser correction for more moderate levels of myopia (less than or equal to 7.0 D of myopic spherical equivalent with or without astigmatism). Further RCTs adequately powered for subgroup analysis are necessary to further elucidate the ideal range of myopia for phakic IOLs.

Comparative analysis of white-to-white and angle-to-angle distance measurements with partial coherence interferometry and optical coherence tomography

PURPOSE

To perform white-to-white (WTW) and angle-to-angle (ATA) distance measurements with 2 optical devices and analyze the correlation with other anterior segment parameters.

SETTING

Department of Ophthalmology, Medical Health and Science Center, University of Debrecen, Debrecen, Hungary.

DESIGN

Comparative case series.

METHODS

In this prospective study, the WTW distance, axial length (AL), and anterior chamber depth (ACD) were measured by partial coherence interferometry (PCI) (IOLMaster). The horizontal and vertical ATA distances and ACD were assessed by anterior segment optical coherence tomography (AS-OCT) (Visante).

RESULTS

The mean PCI values were AL, 23.31 mm ± 1.52 (SD); WTW distance, 11.99 ± 0.47 mm; ACD, 2.99 ± 0.4 mm. On AS-OCT, the mean horizontal ATA was 11.43 ± 0.51 mm and the mean vertical ATA, 10.72 ± 0.66 mm. The WTW distance was significantly greater than the horizontal ATA distance, and the horizontal ATA distance was significantly greater than the vertical ATA distance (P<.0001). The correlations between WTW and horizontal ATA (r = 0.51; P<.0001), vertical ATA (r = 0.32; P<.0021), AL (r = 0.45; P<.0001), and patient age (r = -0.28; P = .023) were significant. The PCI WTW distance and ACD were significantly correlated (r = 0.55; P<.0001). There were no significant correlations between AS-OCT horizontal and vertical ATA measurements (r = -0.02; P = 0.79) or between same-device ACD measurements (r = 0.18; P = .15).

CONCLUSIONS

Although PCI WTW and AS-OCT ATA measurements are not clinically interchangeable, the WTW values correlated well with horizontal and vertical measurements and other anterior segment parameters.

Intraocular stability of an angle-supported phakic intraocular lens with changes in pupil diameter

PURPOSE

To use anterior segment optical coherence tomography (AS-OCT) to evaluate the stability of a recently released angle-supported phakic intraocular lens (pIOL) in the anterior segment with changes in pupil diameter.

SETTING

Keratoconus Unit, Vissum Corporation, Alicante, Spain.

METHODS

In this observational cross-sectional study of consecutive eyes with moderate to high myopia, an AcrySof Cachet pIOL was implanted with the aim of minimizing the refractive error. An analysis of the position and stability of the pIOL before and after pharmacologic pupil dilation was performed 3 months postoperatively using the Visante AS-OCT system. A measurement protocol that included several anatomic parameters was developed and applied; the parameter values before and after dilation were compared.

RESULTS

Twenty eyes of 20 patients ranging in age from 24 to 48 years old were evaluated. The anterior chamber depth increased significantly with pupil dilation (mean change 0.06 mm +/- 0.08 [SD]) (P<.01). A significant change was also observed in the distance between the center of the cornea at the endothelial plane and the anterior surface of the pIOL (mean change 0.03 +/- 0.05 mm) (P = .01). The distances between the peripheral edges of the pIOL and the corneal endothelium and the distance between the crystalline lens and the pIOL did not change significantly (P>or=.14).

CONCLUSION

The angle-supported pIOL showed excellent intraocular behavior after pupil dilation, with no shortening of the distance between the pIOL and corneal endothelium at the center or peripheral edges of the pIOL.

Comparison of Eyemetrics and Orbscan automated method to determine horizontal corneal diameter

Purpose:

To compare horizontal corneal diameter measurements using the Orbscan Eyemetrics function and Orbscan corneal topographer.

Materials and Methods:

Seventy-three eyes of 37 patients were included in the study. In all cases, the automated white-to-white (WTW) measurements were obtained using Orbscan by two observers. Using the Eyemetrics function, the WTW was measured manually by the same observers from limbus to limbus using the digital caliper passing through the five point corneal reflections on the Orbscan real image. The data was analyzed using SPSS software for correlation, reliability and inter-rater repeatability.

Results:

The mean horizontal corneal diameter was 11.74 ± 0.32mm (SD) with the Orbscan and 11.92 ± 0.33mm (SD) with Eyemetrics Software-based measurement. A good positive correlation (Spearman r = 0.720, P = 0.026) was found between these two measurements. The coefficient of inter-rater repeatability was 0.89 for the Orbscan and 0.94 for the Eyemetrics software measurements on the anterior segment images. The Bland and Altman analysis showed large limits of agreement between Orbscan WTW and Eyemetrics WTW measurements. The intra-session repeatability scores for repeat measurements for the Orbscan WTW and Eyemetrics measurements were good.

Conclusion:

Eyemetrics can be used to measure WTW and the Eyemetrics measured WTW was longer than the WTW measured by Orbscan.

Excimer laser refractive surgery versus phakic intraocular lenses for the correction of moderate to high myopia

BACKGROUND

Myopia is a condition in which the focusing power (refraction) of the eye is greater than that required for clear distance vision. There are two main types of surgical correction for moderate to high myopia; excimer laser and phakic intraocular lenses (IOLs). Excimer laser refractive surgery for myopia works by removing corneal stroma to lessen the refractive power of the cornea and to bring the image of a viewed object into focus onto the retina rather than in front of it. Phakic IOLs for the treatment of myopia work by diverging light rays so that the image of a viewed object is brought into focus onto the retina rather than in front of the retina. They can be placed either in the anterior chamber of the eye in front of the iris or in the posterior chamber of the eye between the iris and the natural lens.

OBJECTIVES

The aim of this review is to compare the effect of excimer laser refractive surgery versus phakic IOLs for the correction of moderate to high myopia.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library), MEDLINE, EMBASE and Latin American and Caribbean Literature on Health Sciences (LILACS). There were no date or language restrictions in the electronic search for trials. The electronic databases were last searched on 9 December 2009.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing excimer laser refractive surgery and phakic IOLs for the correction of myopia greater than 6.0 diopters (D) spherical equivalent.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We performed data analysis. We summarised data for outcomes using odds ratios. We used a fixed-effect model as only three trials were included in the review.

MAIN RESULTS

This review included three RCTs with a total of 228 eyes. The range of myopia of included patients was -6.0 D to -20.0 D of myopia with up to 4.0 D of myopic astigmatism. The percentage of eyes with uncorrected visual acuity (UCVA) of 20/20 or better at 12 months postoperative was not significantly different between the two groups. Phakic IOL surgery was safer than excimer laser surgical correction for moderate to high myopia as it results in significantly less loss of best spectacle corrected visual acuity (BSCVA) at 12 months postoperatively. However there is a low risk of developing early cataract with phakic IOLs. Phakic IOL surgery appears to result in better contrast sensitivity than excimer laser correction for moderate to high myopia. Phakic IOL surgery also scored more highly on patient satisfaction/preference questionnaires.

AUTHORS' CONCLUSIONS

The results of this review suggest that phakic IOLs are safer than excimer laser surgical correction for moderate to high myopia in the range of -6.0 to -20.0 D and phakic IOLs are preferred by patients. While phakic IOLs might be accepted clinical practice for higher levels of myopia (greater than or equal to 7.0 D of myopic spherical equivalent with or without astigmatism), it may be worth considering phakic IOL treatment over excimer laser correction for more moderate levels of myopia (less than or equal to 7.0 D of myopic spherical equivalent with or without astigmatism). Further RCTs adequately powered for subgroup analysis are necessary to further elucidate the ideal range of myopia for phakic IOLs.

Determination of albumin sorption to intraocular lenses by radiolabeling and confocal laser scanning microscopy

PURPOSE

To determine albumin adsorption profiles and penetration depth of 3 intraocular lens (IOL) materials over time using confocal laser scanning microscopy (CLSM) and radiolabeling.

SETTING

Centre for Contact Lens Research, School of Optometry, and Department of Biology, University of Waterloo, Waterloo, Ontario, Canada.

METHODS

Poly(methyl methacrylate) (PMMA), silicone, and foldable hydrophilic acrylic IOLs were incubated in 0.5 mg/mL bovine serum albumin (BSA) for 1, 7, and 14 days. The BSA was conjugated with lucifer yellow VS to allow identification of the protein location by fluorescent imaging with CLSM. Next, the protein uptake was quantified using 2% (125)I-labeled BSA.

RESULTS

Confocal laser scanning microscopy showed increasing BSA uptake for silicone and PMMA IOLs after 14 days of incubation (P<.05), with an apparent penetration depth of 8.7 microm +/- 1.9 (SD) and 9.2 +/- 1.4 microm, respectively. For hydrophilic acrylic IOLs, BSA was detected at a depth of 38 +/- 7.4 microm after 1 day, followed by an increase to 192.7 +/- 16.2 microm after 14 days. Despite the penetration depth into the hydrophilic acrylic IOLs, quantitative results confirmed that PMMA and hydrophilic acrylic deposited significantly less BSA (mean 278.3 +/- 41.7 ng and 296.5 +/- 33.1 ng, respectively) than silicone IOLs (mean 392.6 +/- 37.6 ng) (P<.05).

CONCLUSIONS

Silicone and PMMA IOL materials showed BSA sorption near the lens surface only, while BSA penetrated deep into the hydrophilic acrylic IOL matrix. Combining the qualitative CLSM method and quantitative radiolabeling technique provided detailed information on protein interactions with implantable biomaterials.

Factors affecting contrast sensitivity with the Artisan phakic intraocular lens for high myopia

PURPOSE

To evaluate the factors affecting postoperative visual function in eyes with Artisan phakic intraocular lenses (PIOLs).

METHODS

This study examined a retrospective noncomparative case series. Phakic IOLs were implanted in 60 eyes of 36 patients with high myopia. Contrast sensitivity for spatial frequencies of 1.1, 1.7, 2.6, 4.2, 6.6, and 10:4 cycles per degree with and without glare and wavefront aberrations were measured before and 3 months after surgery. The area under the log contrast sensitivity function (AULCSF) was calculated from the contrast sensitivity. Stepwise regression analysis was used to assess the factors that affected the postoperative AULCSF.

RESULTS

No significant difference was noted between the preoperative AULCSF without glare and the postoperative AULCSF without glare (P=.886). The mean AULCSF with glare improved significantly after surgery (P=.018). The variables affecting the postoperative AULCSF without glare were axial length (partial regression coefficient B=-0.101, P=.0002) and age (B=-0.008, P=.0063). The variables affecting the postoperative AULCSF with glare were axial length (B=-0.127, P<.0001) and age (B=-0.012, P=.0294). The preoperative refraction showed multicollinearity with the axial length, and coma-like aberration and spherical aberration showed multicollinearity with age.

CONCLUSIONS

Contrast sensitivity without glare was the same before and after surgery and contrast sensitivity with glare improved after surgery. Longer axial length and older age predispose patients to degradation of the postoperative visual function in eyes with Artisan PIOLs.

Corneal diameter measurements by corneal topography and angle-to-angle measurements by optical coherence tomography: evaluation of equivalence

PURPOSE

To determine the equivalence of corneal white-to-white (WTW) diameter and anterior segment angle-to-angle (ATA) measurements.

SETTING

Vissum Instituto Oftalmologico de Alicante, Alicante, Spain.

METHODS

Thirty eyes of 19 patients ranging in age from 20 to 51 years old with no previous ocular surgeries were included in this study. In all cases, the horizontal WTW diameter was measured with a tool provided by the CSO corneal topography system (Costruzione Strumenti Oftalmici) and the horizontal ATA was measured using an optical coherence tomography (OCT) system (Visante, Carl Zeiss Meditec AG). All measurements were repeated 3 times to evaluate intrasession repeatability. The correlation between WTW and ATA measurements was studied, and the interchangeability of the 2 parameters was assessed using the Bland and Altman method.

RESULTS

The mean corneal WTW diameter was 12.25 mm +/- 0.49 (SD) (range 11.34 to 13.16 mm), and the mean ATA distance was 11.76 +/- 0.52 mm (range 10.03 to 12.92 mm). The difference between the 2 parameters was statistically significant (P<.01). A weak, although statistically significant, positive correlation (r = 0.39; P = .03) and a nonpredictive linear model were found. The Bland and Altman analysis showed large limits of agreement between WTW and ATA measurements that are clinically relevant (limits of agreement, -1.59 mm and 0.61 mm). The intrasession repeatability scores for the WTW and ATA measurements were good.

CONCLUSIONS

The WTW and ATA distance measurements were not equivalent and thus are not interchangeable. There was no linear model for an accurate prediction of the ATA from the WTW.

Long-term endothelial changes in phakic eyes after Artisan intraocular lens implantation to correct myopia: five-year study

PURPOSE

To evaluate long-term endothelial cell changes in eyes that had implantation of an iris-fixated phakic Artisan intraocular lens (IOL) for moderate to high myopia.

SETTING

Casa di Cura Villa Igea, Ancona, Italy.

METHODS

Forty-nine eyes of 30 patients having implantation of Artisan IOL for moderate to high myopia were prospectively examined. Preoperative specular microscopy and serial postoperative specular microscopy (Noncon Robo SP 8000, Konan Medical) were performed to evaluate endothelial cell changes over 5 years. Endothelial cell images were collected in the central region of the cornea before surgery and 4, 12, 24, 36, 48, and 60 months after surgery. The endothelial cell density (ECD), coefficient of variation, and percentage of hexagonal cells were determined.

RESULTS

Preoperatively, the mean ECD was 2616 cells/mm(2) +/- 347 (SD), the mean coefficient of variation was 39.6% +/- 4.7%, and the mean percentage of hexagonal cells was 49.2% +/- 6.7%. The mean endothelial cell loss from preoperatively was 2.3% at 4 months, 3.5% at 12 months, 4.7% at 24 months, 6.7% at 3 years, 8.3% at 4 years, and 9.0% at 5 years. Five years after surgery, the mean coefficient of variation was 35.9% +/- 6.9% (P = .1946) and the percentage of hexagonal cells was significantly higher (mean 54.7% +/- 10.3%) (P = .087).

CONCLUSIONS

Continuous endothelial cell loss was observed after surgery during a 5-year follow-up, especially during the first 2 years. A decrease in the coefficient of variation and an increase in the percentage of hexagonal cells were observed over time, reflecting the increasing stability and remodeling of the corneal endothelial cells 5 years postoperatively.