Dysphotopsia in phakic and pseudophakic patients: incidence and relation to intraocular lens type(2)

Wavefront analysis, contrast sensitivity, and depth of focus after cataract surgery with aspherical intraocular lens implantation

PURPOSE

To determine whether implantation of an aspherical intraocular lens (IOL) results in reduced ocular aberrations and improved contrast sensitivity after cataract surgery without critical reduction of depth of focus.

DESIGN

Double-blinded, randomized, prospective study.

METHODS

In an intraindividual study of 25 patients with bilateral cataract, an aspherical IOL (Akreos Advanced Optic [AO]; Bausch & Lomb, Inc., Rochester, New York, USA) was implanted in one eye and a spherical IOL (Akreos Fit; Bausch & Lomb, Inc) in the fellow eye. Higher-order aberrations with a 5- and 6-mm pupil were measured with a dynamic retinoscopy aberrometer at 1 and 3 months after surgery. Uncorrected and best-corrected visual acuity and contrast sensitivity under mesopic and photopic conditions also were measured. Distance-corrected near and intermediate visual acuity were studied as a measurement of depth of focus.

RESULTS

There was no statistically significant difference between eyes in uncorrected and best-corrected visual acuity at 1 and 3 months after surgery. There was a statistically significant between-group difference in contrast sensitivity under photopic conditions at 12 cycles per degree and under mesopic conditions at all spatial frequencies. The Akreos AO group obtained statistically significant lower values of higher-order aberrations and spherical aberration with 5- and 6-mm pupils compared with the Akreos Fit group (P < .05). There was no significant difference in distance-corrected near and intermediate visual acuity between both groups.

CONCLUSIONS

Aspherical aberration-free Akreos AO IOL induced significantly less higher-order aberrations and spherical aberration than the Akreos Fit. Contrast sensitivity was better under mesopic conditions with the Akreos AO with similar results of depth of focus.

Effects of white-to-white diameter and anterior chamber depth on implantable collamer lens vault and visual outcome

PURPOSE

To investigate the effects of anterior chamber depth (ACD) and white-to-white (WTW) diameter on vault in eyes with implantable collamer lenses (ICL V4, STAAR Surgical AG) and to evaluate the effect of vault on visual outcomes and other biometric changes.

METHODS

Twenty-eight eyes of 16 patients who underwent ICL implantation were retrospectively reviewed. Patients were divided into two groups (A1, A2) according to preoperative ACD (> or = 3.3 mm and < 3.3 mm, respectively), two groups (B1, B2) based on WTW diameter (> or = 11.55 mm and < 11.55 mm, respectively), and two groups (C1, C2) according to the difference of ICL diameter and sulcus length (> or = 0.25 mm and < 0.25 mm, respectively). Vault, endothelial cell density, and visual performance were compared between each set of groups. Correlations of vault with WTW diameter, ACD, and diametric difference of the ICL from the sulcus were analyzed.

RESULTS

The high ACD and WTW groups showed significantly higher vaults (0.59 +/- 0.32 mm and 0.57 +/- 0.36 mm, respectively) than the low ACD and WTW groups (0.26 +/- 0.17 mm and 0.25 +/- 0.14 mm, respectively; P = .01 and .01), whereas the differences of diameter between the sulcus and ICL were not related to significant vault differences. The WTW diameter wascorrelated more closely to the vault than the ACD or sulcus diameter (r = 0.70, P < .001), whereas the vault difference did not affect visual quality or endothelial cell density.

CONCLUSIONS

A high WTW diameter or ACD is likely to render a high vault, regardless of any difference in the ICL and sulcus diameters.

The development and assessment of a self-perceived quality of vision questionnaire to test pseudophakic patients

PURPOSE

To develop and test a questionnaire to assess quality of vision in pseudophakic patients.

METHODS

The problems with existing health measurement scales and the need for a new questionnaire are first discussed. Development of the new questionnaire from concept to completion is presented and all stages discussed. The questionnaire is then tested for internal consistency, reliability and validity.

RESULTS

The Cronbach Alpha for internal consistency was 0.92. British Standards Institution repeatability coefficient was satisfactory at 6.6. Discriminant construct validity testing by extreme groups demonstrated excellent discrimination between patients with functionally significant posterior capsule opacification (PCO) and no significant PCO (Mann-Whitney U test, p = 0.001).

CONCLUSION

The questionnaire is validated as a robust, stable measure of pseudophakic visual symptoms with a high degree of clinical utility. It should be invaluable for the many studies that compare outcomes from different forms of modern cataract surgery with implantation of different intraocular lenses.

Comparing the Multifocal Electroretinogram Topography before and after Cataract Surgery

PURPOSE

To investigate whether multifocal electroretinogram (mfERG) topography would be affected by nuclear cataract.

METHODS

Multifocal electroretinograms were recorded from 10 elderly subjects (10 eyes) with nuclear cataract of grade five (LOCS III) before and after cataract surgery (phacoemulsification). Their visual acuity before the cataract surgery was between 6/12 and 6/18. The postoperative period was from 2 to 3 months. None of the subjects had any significant eye disease apart from cataract. The mfERG responses were grouped into six concentric rings for analysis. Both the amplitudes and the latencies of N1 and P1 of first-order responses were used for analysis.

RESULTS

N1 amplitude only from ring 1 increased significantly after cataract surgery. P1 amplitude from ring 1 and ring 2 also increased significantly after cataract surgery. The latencies of neither N1 nor P1 from all rings changed significantly.

CONCLUSIONS

Nuclear cataract could affect the topography of mfERG, so clinicians should be aware of the effects of cataract when interpreting mfERG responses in cataract patients.

Negative dysphotopsia: long-term study and possible explanation for transient symptoms

PURPOSE

To study the incidence, course, and common factors of patients with negative dysphotopsia and consider the possible role of the corneal incision in cases in which symptoms are transient.

SETTING

Private practice and the University of Cincinnati, College of Medicine, Cincinnati, Ohio, USA.

METHODS

Phacoemulsification with implantation of a single-piece acrylic intraocular lens (IOL) was performed in 250 consecutive routine cataract procedures. Patients were asked whether they noticed a temporal shadow on the day after surgery and were followed by serial evaluations for 3 years. Evaluations included subjective questionnaires and objective testing.

RESULTS

The incidence of negative dysphotopsia was 15.2% on the first postoperative day, decreasing to 3.2% after 1 year, then 2.4% after 2 and 3 years. Common findings included a shallow orbit, prominent globe, space greater than 0.45 mm between the iris and IOL by ultrasound biomicroscopy, and perimetric comet-shaped light in the area corresponding to the shadow. Slitlamp revealed a transparent peripheral capsule and a shadow sign in which a linear shadow on the iris became curvilinear as the light from the slit beam was projected through the incision toward the pupil.

CONCLUSIONS

Two groups of patients experienced negative dysphotopsia that rapidly resolved or remained unchanged from the first postoperative day. It is hypothesized that the corneal edema associated with a beveled temporal incision contributes to transient negative dysphotopsia.

Post-capsulotomy dysphotopsia in monofocal versus multifocal lenses

PURPOSE

To compare the photic symptoms experienced by patients with the monofocal SI30 intraocular lens (IOL) with the refractive multifocal SA40 Array IOL after capsulotomy.

METHODS

In this prospective cohort study, 49 eyes of 49 patients (20 multifocal, 29 monofocal IOLs) were assessed following uncomplicated cataract extraction and Nd:YAG capsulotomy equal to the scotopic pupillary diameter. Subjects with post-operative refraction of +/-1.00 or more DS, +/-1.00 or more DC, concurrent ocular pathology, LogMAR acuity of worse than 0.3 for distance or 1.0 for near were excluded. Glare and halo were assessed objectively with computer-generated psychophysical tests (Glare and Halo) and subjective dysphotopic symptoms were evaluated with Tester, Javitt, Winther-Neilsen and Sedgewick questionnaires.

RESULTS

No significant difference was found for mean halo size (square degrees) between monofocals (121.33) and multifocals (97.32, p = 0.207) or for mean glare (percentage contrast), monofocals (7.881) and multifocals (7.353, p = 0.812). No significant differences in the subjective appreciation of dysphotopsia were found: Tester (p = 0.358), Javitt (p = 0.29), Winther-Neilson (p = 0.54) and Sedgewick questionnaires (p = 0.134).

CONCLUSION

The posterior capsule is an important optical medium, which has not been fully considered in other comparative studies and its complete removal eliminates any confounding contribution. The results suggest that after capsulotomy, there is no significant difference in objective or subjective photic phenomena between monofocal and multifocal silicone lenses. Dysphotopic symptoms in patients with refractive multifocal IOLs were comparable to monofocal IOL patients after capsulotomy.

Complications of foldable intraocular lenses requiring explantation or secondary intervention--2007 survey update

The tenth annual survey of complications associated with foldable intraocular lenses (IOLs) requiring explantation or secondary intervention was sent to members of the American Society of Cataract and Refractive Surgery and the European Society of Cataract and Refractive Surgeons. Preoperative data about visual acuity, patient signs and symptoms, and complications requiring IOL removal were evaluated. Complications were then tabulated for each of the following major foldable IOL groups: 1-piece (plate) silicone, 1-piece hydrophobic acrylic with haptics, 3-piece silicone, 3-piece hydrophobic acrylic, 3-piece hydrophilic acrylic (hydrogel), 3-piece unknown, multifocal acrylic, and multifocal silicone. One hundred forty-two surveys were returned for evaluation. Dislocation/decentration, incorrect IOL power, glare/optical aberrations, and IOL calcification were the most common reasons for removing foldable IOLs. Good surgical technique, accurate IOL power measurements, and high manufacturing standards for foldable IOL materials and designs are the most important factors in preventing complications.

Dysphotopsia after cataract surgery: comparison of four different intraocular lenses

AIM

To assess the risk of dysphotopsia after phacoemulsification, with the use of four different intraocular lens (IOL) models.

METHODS

In this prospective randomized study, 600 patients underwent phacoemulsification surgery. Four study groups were formed, according to the type of the IOL implanted: Meridian HP60M [Bausch & Lomb, hydrogel, 6 mm, three piece (3P), square edge, refraction index (RI): 1.470], Acrysof MA60BM (Alcon, acrylic, 6 mm, 3P, square edge, RI: 1.550), Acrysof MA30BA (Alcon, acrylic, 5.5 mm, 3P, square edge, RI: 1.550) and Clariflex (AMO, silicone, 6 mm, 3P, anterior round and posterior square edge, RI: 1.460). Patients were examined for dysphotopsia symptoms after 1 week, 1, 3 and 6 months.

RESULTS

During the first follow-up visit, 117 patients (19.5%) reported dysphotopsia. During the next visits, the actual number of patients still reporting phenomena declined. Optic phenomena occurred less frequently in patients with AMO Clariflex lens, especially when compared to Acrysof (5.5 and 6 mm); IOL odds ratios ranged from 2.27 to 6.7, depending on follow-up time (p value < 0.05). IOL optic diameter was negatively but significantly associated with the risk of dysphotopsia.

CONCLUSIONS

The design of the optic edge and the optic diameter of the IOL play an important role in the occurrence of dysphotopsia. AMO Clariflex, with round anterior and square posterior edge, overcomes the problem of dysphotopsia to a considerable extent.

Visual and optical performance of the Akreos Adapt Advanced Optics and Tecnis Z9000 intraocular lenses: Swedish multicenter study

PURPOSE

To compare the subjective visual and objective optical performance of 2 aspherical intraocular lenses (IOLs), the Akreos Adapt Advanced Optics (AO) (Bausch & Lomb, Inc.) and the Tecnis Z9000 (Advanced Medical Optics, Inc.).

SETTING

Four university hospitals in Sweden.

METHODS

This study comprised 80 patients, 20 each from 4 university hospital centers in Sweden. All patients had bilateral clear corneal phacoemulsification with implantation of an Akreos Adapt AO IOL in 1 eye and Tecnis Z9000 IOL in the other eye according to a randomization protocol. Preoperatively, 90% contrast Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity was measured and the mesopic pupil sizes were determined. Ten to 12 weeks postoperatively, 12.5% and 90% contrast ETDRS visual acuities and photopic and mesopic Functional Acuity Contrast Test chart contrast sensitivities were determined. Wavefront analysis was performed with the Zywave II aberrometer (Bausch & Lomb, Inc.), and a questionnaire on the subjective quality of vision was completed by each patient.

RESULTS

The Akreos AO IOL and Tecnis Z9000 IOL produced similar high- and low-contrast visual acuities as well as photopic and mesopic contrast sensitivities. The Tecnis Z9000 IOL resulted in lower spherical aberrations of the eye (mean 0.05 +/- 0.13 microm versus 0.35 +/- 0.13 microm root mean square, 6.0 mm pupil) (P<.001); however, the Akreos AO IOL provided a larger depth of field (mean 1.22 diopter [D] +/- 0.48 [SD] versus 0.86 +/- 0.50 D, 6.0 mm pupil) (P<.001). Patient satisfaction was generally high, although 68.8% of the patients reported some type of visual disturbance postoperatively. Twenty-eight percent of patients reported better subjective visual quality in the Akreos AO eye and 14%, in the Tecnis Z9000 eye (P<.0001). Accordingly, 33% perceived more visual disturbances in the Tecnis Z9000 eye and 11%, in the Akreos AO eye (P<.0001).

CONCLUSIONS

Maximum reduction of spherical aberration did not maximize subjective visual quality. The higher perceived quality of vision with the Akreos AO IOL could be because of differences in depth of field, IOL material, or IOL design.

Binocular implantation of the Tecnis Z9000 or AcrySof MA60AC intraocular lens in routine cataract surgery

PURPOSE

To compare vision-related quality of life after binocular implantation of the Tecnis Z9000 intraocular lens (IOL) (Advanced Medical Optics) or the AcrySof MA60AC IOL (Alcon).

SETTING

Moorfields Eye Hospital, London, United Kingdom.

METHODS

The study was a double-masked prospective randomized controlled trial. The main outcome measure was the percentage of patients achieving a Visual Function-14 (VF-14) score of 90 or higher. Additional outcome measures were dysphotopsia symptom scores, a 5-point subjective grading of overall satisfaction, refraction, photopic and mesopic best corrected visual acuities, uncorrected visual acuity, Pelli-Robson contrast sensitivity, aberrometry, infrared pupillometry, and evaluation of posterior capsule opacification scores.

RESULTS

Seventy-nine patients who had bilateral implantation of the Z9000 IOL and 100 patients who had bilateral implantation of the MA60AC IOL were assessed a mean of 7.9 months +/- 2.9 (SD) (range 4 to 16 months) after second-eye surgery. Spherical aberration (mean: Z9000, 0.00 microm +/- 0.06 [SD]; MA60AC, +0.14 +/- 0.09 microm) and root mean square scores for higher-order aberrations combined (mean: Z9000, 0.26 +/- 0.11 microm; MA60AC, 0.32 +/- 0.14 microm) were significantly lower in patients with the Z9000 IOL (P<.001 and P = .007, respectively). The VF-14 scores were 90 or higher in 96.2% of Z9000 patients and 90.0% of MA60AC patients (P = .15). It is unlikely that this weak trend in favor of the Z9000 IOL was clinically significant. The VF-14 scores were heavily skewed toward a perfect outcome and similarly distributed in both groups (median 100; interquartile range 98 to 100). Results for all other outcomes, including measures of acuity, were similarly distributed in Z9000 patients and MA60AC patients.

CONCLUSIONS

The Z9000 IOL reduced spherical aberration compared with the MA60AC IOL. No improvement in subjective visual function using the VF-14 questionnaire was detected.

Long-term Effect of 1-Piece and 3-Piece Hydrophobic Acrylic Intraocular Lens on Posterior Capsule Opacification

PURPOSE

To compare the intensity of posterior capsule opacification (PCO) between the 1-piece and 3-piece haptic designs of the foldable hydrophobic acrylic AcrySof intraocular lens (IOL) over a 5-year period.

DESIGN

Randomized, prospective, patient- and examiner-masked clinical trial with intraindividual comparison.

PARTICIPANTS

Fifty-two patients with bilateral age-related cataract (104 eyes).

METHODS

Each study patient had cataract surgery in both eyes and received a 1-piece AcrySof IOL in 1 eye and a 3-piece AcrySof IOL in the other eye. Follow-up examinations were performed at 1 week, 1 month, 6 months, and 1, 2, and 5 years. Digital retroillumination images were obtained of each eye. The amount of posterior capsule opacification (score range, 0-10) was assessed subjectively at the slit lamp and objectively using automated image analysis software 1, 2, and 5 years after surgery.

MAIN OUTCOME MEASURE

Posterior capsule opacification score (scale, 0-10).

RESULTS

There was no significant difference between the 1-piece and 3-piece AcrySof IOL in best-corrected visual acuity, overlap of rhexis and IOL, capsular folds, anterior capsule opacification, and posterior capsule opacification (1-piece AcrySof PCO score, 1.7+/-1.7; 3-piece AcrySof PCO score, 1.3+/-1.4; P = 0.30).

CONCLUSIONS

Modification of the IOL haptic design of the sharp optic edged AcrySof IOL from a 3-piece to a 1-piece haptic design caused no significant change in PCO intensity and neodymium:yttrium-aluminium-garnet laser treatment rate 5 years after surgery.

Comparison of pseudophakic dysphotopsia with Akreos Adapt and SN60-AT intraocular lenses

PURPOSE

To determine the relative incidence of unwanted light images with the AcrySof SN60-AT intraocular lens (IOL) (Alcon) and the Akreos Adapt (Bausch & Lomb) IOL.

SETTING

The Eye Clinic, Sir Charles Gairdner Hospital, Nedlands, Australia.

METHODS

In a prospective randomized study of 61 patients who had cataract surgery, the relative incidence of unwanted light images with 2 biconvex acrylic double square-edged IOLs, the SN60-AT and Akreos Adapt, was compared. Patients were followed at 1 week and for a minimum of 6 weeks. At both follow-ups, patients were asked to rate their experience of dysphotopic phenomenon according to a set of questionnaire criteria. The Mann-Whitney test was used to analyze the ordinal data.

RESULTS

All 61 patients were interviewed at both stages of follow-up. The mean follow-up was 8 weeks +/- 2 (SD). At 1 week, there was significantly more dysphotopsia (positive and negative) with the SN60-AT IOL (37.5%) than with the Akreos Adapt IOL (24.1%) (P = .042). Significantly more patients with the SN60-AT IOL reported negative dysphotopsia at 1 week only. At 8 weeks, the incidence of positive and negative dysphotopsia declined to 31.3% and 20.7% in the SN60-AT group and Akreos Adapt group, respectively, and there was no longer a statistically significant difference between the 2 groups.

CONCLUSIONS

More patients with the SN60-AT IOL than with the Akreos Adapt IOL reported dysphotopsia. One week postoperatively, the difference was significant. The difference was primarily a result of the higher incidence of negative dysphotopsia with the SN60-AT IOL. At 8 weeks, the incidence of all types of light phenomena was significantly lower in both groups.

Routine posterior optic buttonholing for eradication of posterior capsule opacification in adults: report of 500 consecutive cases

PURPOSE

To study the efficacy of posterior optic buttonholing (POBH) through a primary posterior capsulorhexis (PPCCC) to preserve full capsular transparency, and its potential as a routine alternative to standard in-the-bag implantation of sharp-edged optic intraocular lenses (IOLs).

SETTING

Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.

METHODS

After standard cataract removal, a PPCCC 4.0 to 5.0 mm in diameter was performed and the optic of a 3-piece IOL buttonholed posteriorly. One third of the eyes additionally had extensive anterior capsule polishing. All surgeries were performed under topical anesthesia.

RESULTS

The first 500 consecutive surgeries were evaluated. In 11 eyes, POBH was not performed as planned. In 4 cases, anterior capsulorhexis fixation of the optic was used as an alternative. In the early series, vitreous entanglement was seen in 5 eyes, of which 1 case prompted translimbal anterior vitrectomy. No case of cystoid macula edema was observed. One case of peripheral retinal detachment in a highly-myopic eye 4 months postoperatively appeared to be unrelated to the surgery. All lenses were well-centered without tilt, and both capsule leaves remained clear especially after additional polishing.

CONCLUSION

Posterior optic buttonholing precludes lens epithelial cells from accessing the retrolental space. The sandwiched posterior capsule blocks optic contact and thus fibrosis of the anterior capsule. Posterior optic buttonholing avoids after-cataract independent of optic edge design. Anterior capsule polishing adds to its efficacy by excluding any residual fibrosis. Surgery under topical anesthesia was well-controlled and safe. Posterior optic buttonholing may become a routine alternative to standard in-the-bag IOL implantation when supported by a longer follow-up.

Severe photic phenomenon

A 69-year-old man who had uneventful bilateral cataract surgery with visual acuity of 20/15 without correction presented with severe dysphotopsia. Treatment with brimonidine (Alphagan) or pilocarpine did not resolve the symptoms. A multipiece silicone intraocular lens was piggybacked into the sulcus, and the patient no longer reported dysphotopsia.

Recent developments in pseudophakic dysphotopsia

PURPOSE OF REVIEW

Photic phenomena associated with intraocular lenses can degrade visual performance following intraocular lens implantation. Postoperative dysphotopsia introduces glare, halos, starbursts and shadows in a small number of patients. Understanding the optical mechanisms behind the introduction of these artifacts can lead to improved lens design and a reduction in the deleterious effects of stray light. This review looks at the improvement efforts of recent years to illustrate the systematic hunt for lens problems.

RECENT FINDINGS

Improvements in edge designs have diminished the effects of positive dysphotopsia. However, negative dysphotopsia remains poorly understood and a variety of lens designs and materials can cause negative dysphotopsia. In other efforts, a testing procedure has been developed to improve understanding of the visual percept of a patient suffering dysphotopsia. This test should enlighten practitioners to the deficits their patients face and provide clues to the root causes of the problems.

SUMMARY

Intraocular lenses can introduce stray light artifacts into the eye. These artifacts manifest themselves as glare, halos, starbursts and shadows. While positive dysphotopsia (glare, halos and starbursts) has been largely attributed to edge effects of the implant, negative dysphotopsia remains somewhat mysterious and appears to be more related to the patient's anatomical structure than to specific lens designs or materials.

A Comparison of Higher Order Aberrations Following Implantation of Four Foldable Intraocular Lens Designs

PURPOSE

To determine the higher order aberrations following implantation of four foldable intraocular lens (IOL) designs.

METHODS

One hundred twenty-two eyes were randomly assigned to undergo implantation with one of four foldable IOL designs--Collamer (STAAR Surgical, Monrovia, Calif), plate haptic silicone (STAAR Surgical), AcrySof (Alcon, Ft Worth, Tex), or the Sensar (Advanced Medical Optics, Santa Ana, Calif). All enrolled eyes underwent wavefront assessment using the Tracey Visual Function Analyzer (Tracey Technologies, Houston, Tex).

RESULTS

Preoperatively, no significant differences were noted in higher order aberrations between the four lens groups. No significant differences were noted among the plate haptic silicone, Sensar, or AcrySof lenses at 1 week or 1 month postoperatively, or among the Collamer, plate haptic silicone, or Sensar lenses, with regard to total higher order aberrations, although differences were observed in individual aberration terms. At 1 week and 1 month postoperatively, the Collamer IOL had significantly less higher order aberrations than the AcrySof lens (P < .01). Significantly less third and fourth order aberrations, coma, trefoil, spherical aberration, and tetrafoil were observed postoperatively with the Collamer than the AcrySof IOL. There were no parameters where the AcrySof had significantly less optical aberrations than the Collamer.

CONCLUSIONS

The Collamer IOL design is associated with fewer higher order aberrations than the AcrySof lens.

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.

Changing indications for and improving outcomes of intraocular lens exchange

PURPOSE

To evaluate the indications for and outcomes of intraocular lens (IOL) exchange at the same clinical setting over the past decade, as well as compare the efficacy and safety of anterior chamber lens (AC-IOL) and posterior chamber lens (PC-IOL) implantation for IOL exchange.

DESIGN

Retrospective, nonrandomized case series.

METHODS

The charts of all patients who had an IOL exchange at the Eye Institute of Utah between January 1998 and December 2004 were reviewed. The rate, indications, and outcomes are compared with the data of our previous study conducted between 1986 and 1990.

RESULTS

This study comprised 51 eyes of 51 consecutive patients. The rate of IOL exchange was 0.77% of all cataract surgeries during the time considered. Incorrect IOL power (41.2%), decentration/dislocation (37.3%), and glare (7.8%) were the most common indications for IOL exchange. An AC-IOL was used in 14 eyes (27.5%) and a PC-IOL in 37 eyes (72.5%) for IOL exchange. None of the PC-IOLs was sutured to the sclera or iris. Overall, 90.2% of patients obtained a best-spectacle corrected visual acuity (BSCVA) of 20/40 or better. All eyes in AC-IOL group and 94.6% of eyes in PC-IOL group maintained within 1 line or improved 2 to 5 lines of the pre-exchange vision.

CONCLUSIONS

The improvements in IOL design and materials as well as surgical techniques have greatly minimized the incidence, changed the indications for, and improved the visual outcomes of IOL exchange over the past decade. Our study suggests that the open loop, flexible AC-IOL poses no greater risk than PC-IOL with respect to visual outcome and safety for IOL exchange. An AC-IOL may be preferable to a PC-IOL suture fixation for IOL exchange in the absence of posterior capsular support.

Acute haptic-induced ciliary sulcus irritation associated with single-piece AcrySof intraocular lenses

We report an analysis of 3 single-piece hydrophobic acrylic intraocular lenses (IOLs) that were explanted because of complications related to the presence of their haptics in the ciliary sulcus. In 2 cases, the IOL was primarily implanted in the ciliary sulcus because of inadequate posterior capsule support. In the third case, postoperative displacement of 1 haptic in the sulcus was associated with hyphema and vitreous hemorrhage. Ultrasound biomicroscopy confirmed the contact between the haptic and iris. Areas of iris atrophy were observed in all cases. Light microscopy and scanning electron microscopy of the explanted lenses revealed the presence of pigmentary dispersion on the anterior surfaces. In Case 3, the pigments were concentrated on the surface of the haptic that was displaced from the capsular bag and on the corresponding optic-haptic junction. Scanning electron microscopy also showed the IOL's squared edges and unpolished side walls. The flexibility and thickness of the single-piece hydrophobic acrylic haptics, as well as the square optic and haptic edges, may increase the risk for iris chafing when the haptics are in the sulcus. Therefore, sulcus fixation of this IOL design is not recommended.

The effect of lens design on dysphotopsia in different acrylic IOLs

PURPOSE

To compare the incidence and severity of all grades of dysphotopsia in three types of acrylic intraocular lenses: the Acrysof MA30 BA and MA60 BM IOLs (Alcon) and the Akreos Fit one-piece IOL (Bausch and Lomb).

METHODS

In all 111 patients were prospectively recruited who had undergone uncomplicated cataract surgery in the previous 12 months. Patients were assessed using a combination of a questionnaire and standardised provocation test, and were scored on a grading scale of 0-6 (0 indicating no glare and 6 indicating the most severe symptoms).

RESULTS

The overall incidence of dysphotopsia was 77.7%. Patients with absent or mild symptoms (scoring 2 or less on the grading scale) were greater in the group implanted with the Akreos IOLs (49/65 eyes, 75%) as opposed to (44/92 eyes, 48%) of the eyes implanted with Acrysof lenses. Patients with more marked symptoms of glare as judged by scores of 5-6 were uncommon, but more prevalent in the Acrysof lenses (12/92 eyes, 13%) compared to the Akreos lenses (3/65 eyes, 4.6%) respectively. Statistically the Mann-Whitney test showed that there was significantly less dysphotopsia with the Akreos lens when compared to the Acrysof MA30 (P=0.005) and MA60 lenses (P=0.002).

CONCLUSION

This study demonstrates that dysphotopsia symptoms are commonly seen in certain brands of Acrylic IOLs. However, differences in design (not only related to the edge) significantly reduce the incidence of moderate and severe grades of dysphotopic symptoms.

Negative dysphotopsia associated with implantation of the Z9000 intraocular lens

Uneventful small-incision cataract surgery was performed in a 70-year-old man and a 62-year-old woman with implantation of a Tecnis Z9000 intraocular lens (IOL) (Pharmacia). No ocular pathology was present in the patients preoperatively. Unsolicited complaints of negative dysphotopsia were made postoperatively, and the symptoms have persisted for more than 1 year in both patients. Symptomatic negative dysphotopsia may be seen in association with the Z9000 IOL.

Glare disability and spherical aberration with five foldable intraocular lenses: a prospective randomized study

PURPOSE

To compare differences in subjective glare and spherical aberration between five foldable intraocular lenses (IOLs) made of different materials and to different designs.

METHODS

This prospective study comprised 175 cataract patients who underwent phacoemulsification and were randomized to receive one of five types of foldable IOL (AcrySof MA30BA, Alcon; Sensar AR40, AMO; AcrySof SA30AL, Alcon; Sensar AR40e, AMO, and Tecnis Z9000, Pharmacia & Upjohn). All patients received a questionnaire investigating the incidence of subjective photic phenomena. Two months postoperatively, we collected data regarding subjective glare and evaluated pupil size, visual acuity and wavefront aberration of the cornea and eye.

RESULTS

With regard to difficulty in performing ordinary activities under different light conditions and light and dark adaptation, the difference between the groups was not significant (p > 0.05, chi-squared test). With respect to difficulty in driving at night, the MA30BA group had a significant higher incidence of photic phenomena than the SA30AL, AR40e and Z9000 groups (p < 0.05, chi-squared test). Wavefront measurements revealed a significant difference between the Z9000, AR40e and SA30AL groups, which showed the lowest values, and the MA30BA group, which showed the highest value (p < 0.05, anova with Tamhane posthoc test).

CONCLUSIONS

New generation IOLs such as the Pharmacia Z9000, AMO AR40e and AcrySof SA30AL have a lower incidence of glare and spherical aberrations; however, their impact on future IOL design should be conditioned by further data, especially regarding posterior capsule opacification.

Complications of foldable intraocular lenses requiring explantation or secondary intervention--2003 survey update

The sixth annual survey of complications associated with foldable intraocular lenses (IOLs) requiring explantation or secondary intervention was sent to members of the American Society of Cataract and Refractive Surgery and the European Society of Cataract and Refractive Surgeons. Preoperative data about visual acuity, patient signs and symptoms, and complications requiring IOL removal were evaluated. Complications were then tabulated for each of the following major foldable IOL groups: 3-piece monofocal silicone, 3-piece hydrophobic acrylic, 1-piece hydrophobic acrylic with haptics, 3-piece hydrophilic acrylic (hydrogel), 1-piece hydrophilic acrylic (hydrogel), 1-piece plate-type silicone, 3-piece multifocal silicone, and Collamer. Two hundred seventy-three surveys were returned for evaluation. Dislocation/decentration, incorrect lens power, IOL calcification, and glare/optical aberrations were the most common reasons for removing foldable IOLs. Good surgical technique, accurate IOL power measurements, and high manufacturing standards for foldable IOL materials and designs are the most important factors in avoiding complications with foldable IOLs.

Development of a Forced Choice Photographic Questionnaire for Photic Phenomena and Its Testing – Repeatability, Reliability and Validity

AIM

To design, develop and test a system for analysis of photic phenomena.

METHOD

Extensive background research, patient interviews and theoretical studies led to development of a set of photographic images resembling photic phenomena experienced by patients. These photographic images were processed and digitally altered to create scales of severity for each photic phenomenon in which patients indicated their severity of symptoms by choice of image. The system was tested for stability and validity.

RESULTS

The system showed excellent repeatability and reliability. Face, content, criterion and construct validity were all found to be acceptable.

CONCLUSION

The photographic images of photic phenomena analyser is an acceptable, validated measure for the assessment of photic phenomena, in both pseudophakic patients and those with cataract.

Comparison of posterior capsule opacification between the 1-piece and 3-piece Acrysof intraocular lenses: two-year results of a randomized trial

PURPOSE

To compare intensity of posterior capsule opacification (PCO) between the 1-piece and 3-piece haptic designs of an open-loop hydrophobic acrylic intraocular lens (IOL).

DESIGN

A randomized, patient- and examiner-masked clinical trial with intraindividual comparison.

PARTICIPANTS

Fifty-two patients with bilateral age-related cataract (104 eyes).

METHODS

Each patient had cataract surgery in both eyes and received a 1-piece Acrysof IOL in one eye and a 3-piece Acrysof IOL in the fellow eye. Follow-up examinations were at 1 week, 1 month, 6 months, 1 year, and 2 years. Patients were examined at the slit lamp, visual acuity (VA) was determined, and standardized high-resolution digital retroillumination images of the posterior capsule were taken. The intensity of PCO was assessed subjectively at the slit lamp and objectively using automated image analysis software.

MAIN OUTCOME MEASURE

Posterior capsule opacification score (scale, 0-10).

RESULTS

There was no significant difference between IOL styles in best-corrected VA, rhexis/IOL overlap, capsular folds, and amount of anterior capsule opacification during the follow-up period. One year postoperatively, the amount of regeneratory PCO was higher for the 1-piece Acrysof eyes (image analysis software score: 1.3) than for the 3-piece Acrysof eyes (score: 0.9; P = 0.002). However, 2 years postoperatively, there was no significant difference between the 2 IOL styles (1-piece: 1.5; 3-piece: 1.3; P = 0.3). Neodymium:yttrium-aluminum-garnet capsulotomy was not performed in the study.

CONCLUSION

One year postoperatively, the 1-piece Acrysof showed slightly more regeneratory PCO than the 3-piece Acrysof. However, 2 years postoperatively, the barrier effect of the 1-piece design was comparable to that of the 3-piece haptic design, with low PCO intensity.

Effect of a modified optic edge design on visual function

PURPOSE

To compare the impairment in visual function caused by glare with 2 acrylic intraocular lenses (IOLs) with different modified optic edges.

SETTING

Hayashi Eye Hospital, Fukuoka, Japan.

METHODS

Fifty-four patients had implantation of an IOL with a textured edge (Alcon MA60AC) in 1 eye and an IOL with a round-anterior, sloped-sided edge (AMO AR40e) in the opposite eye. Visual acuity was measured at 5 contrast visual targets (100%, 25%, 10%, 5%, and 2.5%) (contrast visual acuity) under photopic and mesopic conditions with and without a glare source approximately 1 month after surgery using the Contrast Sensitivity Accurate Tester (Menicon CAT-2000).

RESULTS

The mean mesopic contrast visual acuity at moderate- to low-contrast visual targets was significantly worse in the presence of a glare source in both groups, whereas photopic contrast visual acuity did not change significantly. There were no significant differences between the 2 groups in the mean visual acuity or in photopic or mesopic lighting contrast visual acuity with and without a glare source. Furthermore, there was no significant difference in loss of contrast visual acuity in the presence of glare.

CONCLUSION

Mesopic contrast sensitivity with both acrylic IOLs was impaired significantly in the presence of glare, but the impairment of contrast sensitivity from glare was approximately the same between eyes with a textured-edge IOL and eyes with a round-anterior, sloped-sided edge IOL.

Peripheral light focusing as a potential mechanism for phakic dysphotopsia and lens phototoxicity

Our aim was to examine secondary image formation in the anterior segment caused by peripheral light focusing (PLF) in the human cornea, and in particular the crystalline lens. Non-sequential ray-tracing (OptiCAD) was applied to an anatomically based human eye model, which incorporates a gradient index crystalline lens. For analysis of the limbal effect, we varied the incident angle from 100 to 122 degrees, while for the crystalline lens effect, the incident angle was varied from 60 to 90 degrees. The corneal shapes studied included central radii from 7.4 to 8.2 mm with a range of shape factors. In each case, we computed the peak and average intensities, and the area of exposure at the limbus or lens periphery. The computation was repeated with a previous model eye for comparison. For the limbal effect, a peak intensity gain of x22.5 was found at an incident angle of 104 degrees which compares well with previous results. The average intensity gain at this angle was x7.5 over an area of 0.23 mm2. Steeper corneal curvature produced a greater PLF effect. For the crystalline lens effect, maximum UVA (365 nm) intensity gain peaked at x8.6 at 84 degrees with average intensity gain of x2.3. The area of UVA exposure peaked at 4.7 mm2 at 70 degrees. A relatively wide range (30 degrees ) of incident angles produced peak PLF gains of x3 or more in the lens. Significant focusing of light is directed to the nasal limbus, and to a lesser extent to the crystalline lens over a broad range of incident angles. PLF in the nasal cornea is reduced by an order of magnitude when a UV-blocking soft contact lens is used. The concentration levels and intraocular sites of PLF action on UV and visible light suggest a new mechanism of phakic dysphotopsia and lens phototoxicity.

Analysis of stray-light effects related to intraocular lens edge design

PURPOSE

To study the behavior of light rays that impact the frosted, double-square edge of an intraocular lens (IOL).

SETTING

Optical Phisiophatological Department, University of Florence, Florence, Italy.

METHODS

The interaction of light rays as a function of the edge design of a frosted, sharp-edged IOL was evaluated using an experimental eye model and an advanced ray-tracing program. The model simulates the irregularities of the frosted edge by the random overlap of sinusoidal phase gratings that have a random phase, an orientation, and a fixed period.

RESULTS

The reduction in the maximum intensity of the ghost image by frosting the square edge was linked to the period of the microroughness. At a maximum microroughness, when the period is less than 5 microm, the reduction in the value of an unfrosted, square-edged IOL was 17.5%.

CONCLUSIONS

The frosted edge had a small impact on reducing the intensity of the ghost image caused by the reflection of light from the double square edge of the IOL. Furthermore, in optics, the stray light from microroughness is generally considered to be a drawback because it can decrease contrast sensitivity.

Eccentric capsulorhexis and postoperative dysphotopsia following phacoemulsification

We report a case of troublesome visual symptoms or dysphotopsia in a 68-year-old patient after right phacoemulsification and implantation of a 3-piece AcrySof(R) MA60BM acrylic intraocular lens (IOL) (Alcon) in the capsular bag. The patient described multiple horizontal streaks in dim lighting conditions with light sources in the right temporal visual field. The anterior capsulorhexis was eccentric, leaving the nasal optic edge and site of polypropylene haptic insertion uncovered by the semi-opaque anterior capsule and the probable source of the flare images. Miotic therapy was poorly tolerated and IOL exchange declined. The case illustrates the importance of creating a central capsulorhexis smaller than the IOL optic to reduce the risk photic phenomena and edge effect with square-edged IOLs.

Single-piece hydrophobic acrylic intraocular lens explanted within the capsular bag

A 74-year-old woman had uneventful phacoemulsification with implantation of a single-piece hydrophobic acrylic intraocular lens (IOL) (SA30AL) in her left eye. Two weeks after the surgery, the patient presented for ophthalmological consultation reporting pseudophakic dysphotopsia, which she had subjectively noted since surgery. Explantation/exchange of the IOL was performed 3 months after the surgery. The IOL was strongly attached to the capsule, which was fibrotic and contracted; explantation of the capsular bag complex in toto was done. To our knowledge, this is the first case of explantation of this IOL design with clinicopathological correlation.

Principles of Pseudophakic Photic Phenomena

As ophthalmic science develops, the expectations of surgeons and patients undergoing cataract or refractive surgery also advance. Good Snellen visual acuity is not always an indicator for patient satisfaction, and the surgeon must understand the nature and pathogenesis of problems with other less recognised visual functions. This paper discusses the phenomenon of unwanted light images that may occur after surgery due to optical media imperfections, termed pseudophakic photic phenomena. It covers definitions, assessment, high-risk groups and possible explanations for the occurrence of such phenomena.

A clinical comparison of single-piece and three-piece truncated hydrophobic acrylic intraocular lenses

PURPOSE

To determine the clinical differences between three-piece (3P) and single-piece (SP) truncated hydrophobic acrylic intraocular lenses (IOL).

DESIGN

Retrospective cohort clinical study.

METHODS

The setting was an academic clinical practice. The patient population consisted of subjects without confounding comorbidity that could effect central vision with at least 1-year follow-up after uncomplicated surgical placement of 3P or SP IOLs in the capsular bag and at least 20/25 best-corrected postoperative vision documented. Observation procedures were as follows: logarithm of the minimal angle of resolution (LogMAR) visual acuity (uncorrected and best corrected), digital retroillumination photographs to ascertain posterior capsular opacification (PCO), anterior capsular opacification (ACO), IOL centration, and refractive stability by comparing this refraction with the early postoperative refraction. Patients completed a dysphotopsia questionnaire. Main outcome measures were as follows: LogMAR visual acuity (uncorrected and best corrected), PCO, ACO, IOL centration, refractive stability, and dysphotopsia outcomes comparing 3P and SP.

RESULTS

Seventy-five patients were enrolled (36 3P and 39 SP). Corrected and uncorrected visual acuity, refractive stability, and IOL centration were similar. Single piece truncated hydrophobic acrylic intraocular lenses had more PCO (P =.013), less ACO (P =.001), less central flash looking at a peripheral light (P =.044), and less unwanted images to the side of a light source (P =.025) .

CONCLUSIONS

Although similar in centration and refractive stability, SP has more PCO, less ACO, and less dysphotopsia than 3P.

Off-axis edge glare in pseudophakic dysphotopsia

PURPOSE

To characterize peripheral light focusing of oblique off-axis light in the edge-glare phenomenon associated with pseudophakic dysphotopsia.

SETTING

Department of Ophthalmology, Prince of Wales Hospital, The University of New South Wales, Sydney, Australia.

METHODS

Nonsequential optical ray-tracing (OptiCAD) was performed on a model pseudophakic human eye with an intraocular lens (IOL). The acrylic IOL had an anterior radius of 14.23 mm, posterior radius of 25.00 mm, center thickness of 0.72 mm, diameter of 6.00 mm, and refractive index of 1.5597. Peripheral light focusing caused by off-axis light was calculated for light rays incident on the temporal cornea at angles between 0 degrees and 120 degrees to the sagittal plane.

RESULTS

Light incident on the temporal cornea at oblique angles was able to strike the nasal portion of the IOL and the nasal retina. The focusing gain was 2.56 times the incident intensity. The critical incidence window at the temporal cornea was between 71 degrees and 89 degrees to the sagittal plane. The light-focusing effect created foci of light in the nasal edge region of the IOL. In the mid range of permissive angles, up to 3 secondary images were formed, some of which may be apparent only under scotopic conditions.

CONCLUSION

Off-axis light incident at the temporal cornea formed intense foci in the nasal edge of the IOL. Multiple secondary images can be formed. These spots constitute glare sources and may be of sufficient intensity to disturb vision. These findings indicate that off-axis light may be an important contributor to some disability glare problems and that IOL edge design should be reevaluated to minimize dysphotopsia associated with peripheral focusing effects.

Cataract treatment in the beginning of the 21st century

PURPOSE

To describe the principles upon which present day cataract treatment success resides.

DESIGN

Literature review and collective experience of the authors.

RESULTS

Surgical removal remains the standard treatment for cataract now and in the foreseeable future. Ultrasound cataract removal with a foldable "in-the-bag" intraocular lens with a truncated edge treated for dysphotopsia best correlates with core treatment principles, as we now understand them. Improving refractive results is an important trend. The worldwide burden of this problem is immense.

CONCLUSIONS

While results for treatment of cataracts are excellent today, improvements in safety and refraction precision are needed. Other approaches are desperately needed to stem the worldwide tide of cataract related ocular dysfunction.

Intraocular lens surfaces and their relationship to postoperative glare

PURPOSE

To estimate the potential for surface reflections in recently introduced intraocular lenses (IOLs) and to determine optic surface designs that will reduce surface reflections.

SETTING

Mayo Clinic, Rochester, Minnesota, USA.

METHODS

Surface-reflected glare in the unaccommodated human crystalline lens and in 6 IOLs (Bausch & Lomb SoFlex LI61U, Pharmacia CeeOn 911A, Allergan Sensar AR40, Bausch & Lomb Hydroview H60M, Alcon AcrySof MA60BM, Alcon AcrySof SA30AL) was examined in a physiologic eye model using the ZEMAX optical design program. Internal and external surface reflections were described and compared in terms of IOL surface reflectivity (%), area of the reflected glare image (mm(2)), and relative intensity of the reflected glare image.

RESULTS

Compared to surface reflections from the unaccommodated human lens with a corneal power of 43.0 diopters, all the IOLs increased the relative intensity of internal and external reflections by 3- to 36-fold except the MA60BM and the SA30AL, which increased the relative intensity of internal and external reflections by 730- to 1090-fold.

CONCLUSIONS

All the IOLs studied variably increased internal and external surface reflections when compared to the human crystalline lens. Surface reflections were minimized in optic designs with an anterior radius of curvature of approximately 17.0 mm or less.

Computerized analysis of the effects of intraocular lens edge design on the quality of vision in pseudophakic patients

PURPOSE

To study the distribution and intensity of reflected glare images from 3 intraocular lens (IOL) edge designs.

SETTING

Eye Institute, University of Florence, Florence, Italy.

METHODS

The interaction of light rays as a function of edge design was evaluated using an experimental eye model and an advanced ray-tracing program. Three hydrophobic acrylic IOLs were studied: an acrylic square-edged (sharp) design, an acrylic round-edged design, and a new acrylic IOL with a rounded anterior edge and a sharp posterior edge.

RESULTS

The rays hitting the sharp edge of an IOL caused peripheral arcs or circles of light on the side of the retina opposite the focused image. Edge reflections also occurred with the round-edged IOL, but the intensity of the reflected image was one tenth that of the intensity with the sharp-edged design. The new round-/sharp-edged design reduced the maximum intensity of the reflected image to one third the intensity of the sharp-edged reflected image.

CONCLUSIONS

The experimental findings with an acrylic IOL that combines a sharp posterior edge with a low incidence of reflected edge glare are promising.

Complications of foldable intraocular lenses requiring explantation or secondary intervention--2001 survey update

A survey of the complications associated with foldable intraocular lenses (IOLs) that required explantation or secondary intervention was sent to members of the American Society of Cataract and Refractive Surgery and the European Society of Cataract and Refractive Surgeons. Preoperative data about visual acuity, patient signs and symptoms, and complications requiring IOL removal were assessed. Postoperative results and outcomes were also analyzed. Complications and symptoms for each of the following major groups of foldable IOLs explanted were tabulated separately: 3-piece hydrophilic acrylic or hydrogel; 3-piece monofocal silicone; 3-piece hydrophobic acrylic; 1-piece hydrophobic acrylic with haptics; 3-piece multifocal silicone; 1-piece plate-type silicone. A total of 286 surveys were returned for evaluation. Intraocular lens calcification, incorrect lens power, optical visual aberrations, and decentration/dislocation were the most common reasons for removing a foldable IOL. Accurate IOL measurements, meticulous surgical technique, proper patient counseling, and careful manufacture of foldable IOL materials are the most important factors in avoiding complications with foldable IOLs.

Forceps insertion with incisional anesthesia for Sensar intraocular lenses

This technique to prevent self-adherence of the Sensar acrylic intraocular lens (IOL) optic during forceps insertion with wound stretch includes modifications to the 3-and-9 insertion technique to prevent difficulties that may be encountered with this phenomenon. To decrease patient sensation during IOL insertion and thus improve surgeon control, the corneal tunnel incision is directly anesthetized.

Clinical performance of Alcon SA30AL and SA60AT single-piece acrylic intraocular lenses

PURPOSE

To report the clinical performance characteristics of single-piece acrylic Alcon SA30AL and SA60AT intraocular lenses (IOLs).

SETTING

A private practice in Marshalltown, Iowa, USA.

METHODS

In a review of 2630 consecutive cases operated on from January 2000 through July 2001, ease of IOL insertion and integrity of the haptic architecture were evaluated in a prospective fashion at implantation. Subgroups of cases were studied prospectively to evaluate 3 factors: same-day incision competence after implantation (postoperative intraoperative pressure [IOP], 107 cases); 2- to 5-week A-constant validation (200 cases); 1-day, 2-week, and 1- and 5-month descriptions of optic centration with respect to pupil and capsule anatomy (79 cases); and a 1-day versus 9-month photographic comparison of IOL centration (70 cases). A retrospective evaluation of the population's diagnostic codes tabulated complications including increased postoperative iritis, cystoid macular edema, neodymium:YAG (Nd:YAG) laser intervention for posterior capsule opacification, and pseudophakic dysphotopsia. A retrospective review of a subgroup of 140 consecutive cases was done to categorize postoperative optic clarity.

RESULTS

Overall, the IOLs were easy to implant with no haptic or optic damage using a forceps or the Monarch injector. Subgroup studies confirmed good performance in the following parameters: There were no cases of incision incompetence evidenced by an abnormally low postoperative IOP. The lowest postoperative IOP was 6 mm Hg, with the overall mean IOP increasing to 29 mm Hg from the 17 mm Hg measured a mean of 102 minutes after surgery. The manufacturer's published A-constant was almost identical to that obtained in review (118.4 versus 118.38 for the SA30AL and 118.35 for the SA60AT). In verbal descriptions, IOL optic centration was assessed to be within 0.4 mm of perfect in 75 (95%) of 79 cases. Slitlamp photographs showed that 52 (98%) of 53 IOLs were in the same position 9 months after surgery as on the day of surgery. One IOL optic appeared to rotate 14 degrees. There were no cases of decentration greater than 1.0 mm in either optic centration subgroup. Given a normal postoperative topical steroid regimen, there were no cases of substantially increased or prolonged iritis. There were 17 cases (0.65%) of macular edema. An Nd:YAG laser posterior capsulotomy was performed in 0.64% (13/2044) in the SA30AL group over a mean of 9 months (range 2 to 23 months) and in 0.34% (2/586) in the SA60AL group over a mean of 5.5 months (range 5 to 6 months). Pseudophakic dysphotopsia was diagnosed in 26 eyes of 18 patients (1% of 2630 cases), with 1 patient requiring an IOL exchange. Optic glistenings were observed in 11 (11%) of 100 SA30AL cases at a mean follow-up of 8 months. No glistenings in 40 cases were seen in the SA60AT group at a mean follow-up of 3 months.

CONCLUSIONS

The single-piece acrylic lenses performed well in all regards. Although not as intense as observed with the earlier 3-piece designs, pseudophakic dysphotopsia occurred in a few patients with the single-piece acrylic lens. Intraocular lens exchanges with single-piece IOLs may be accomplished with less difficulty early rather than late.

Use of bipolar diathermy to prevent posterior capsule opacification(1)

PURPOSE

To determine the feasibility of using directed bipolar diathermy to eliminate or reduce the formation of new cortical lens material following phacoemulsification in a rabbit model.

SETTING

Department of Research & Development, Bausch & Lomb Surgical, and Department of Ophthalmology, St. Louis University, St. Louis, Missouri, USA.

METHODS

A rabbit model for posterior capsule opacification (PCO) was used. A continuous curvilinear capsulorhexis was performed followed by phacoemulsification to remove cortical lens material. In 2 experimental groups, modified bipolar instruments were used to apply diathermy to residual lens epithelial cells using an intracapsular or extracapsular method of application. Postoperative clinical examinations were at 1, 3, and 7 days and then weekly up to 60 days. Selected animals were followed for a longer period. Capsule integrity was evaluated by measuring the pressure required to rupture the capsule in similarly treated porcine eyes.

RESULTS

Diathermy prevented PCO in 4 of 4 eyes in the intracapsular treatment group and 4 of 5 in the extracapsular group. Eyes remained free of new lens cortex for the life of the animal, which was as long as 18 months. New cortical material was detected after 35 days in 1 animal in the extracapsular group. Mean time for the formation of observable cortical material was 29 days +/- 5 (SD) in the control animals. Physical measurements did not detect a reduction in capsule integrity with diathermy treatment. The extracapsular treatment method resulted in fewer iris complications.

CONCLUSIONS

Directed diathermy has the potential to eliminate secondary cataract formation with minimal damage to collateral tissues.

Patient satisfaction after uneventful cataract surgery with implantation of a silicone or acrylic foldable intraocular lens. Comparative study

PURPOSE

To compare patient satisfaction with vision 12 months after implantation of a silicone or acrylic foldable intraocular lens (IOL).

SETTING

John A. Moran Eye Center, University of Utah Medical Center, Salt Lake City, Utah, USA.

METHODS

Selection criteria included patients who had uneventful cataract extraction by phacoemulsification with a temporal clear corneal incision or superior scleral tunnel incision, a curvilinear capsulorhexis, and in-the-bag IOL placement. One hundred sixty-two patients surveyed had a mean follow-up of approximately 15 months (range 12 to 18 months). Patients were divided into 3 groups of 54 each based on IOL type: AMO SI-30/40, Alcon MA30BA, and Alcon MA60BA. All patients were surveyed over the telephone using a standardized questionnaire protocol. They were questioned about their perception of vision with best optical correction in relation to visual blurring symptoms, glare symptoms, night vision, near vision, and overall vision.

RESULTS

There were no significant differences in patient satisfaction among the 3 IOL groups in visual blurring or night vision. Patients in the SI-30/40 and MA60BA groups reported significantly higher satisfaction with glare symptoms, near vision, and overall satisfaction than patients in the MA30BA group.

CONCLUSION

The SI-30/SI-40 and the MA60BA IOLs received significantly higher patient satisfaction scores than the MA30BA IOL in glare symptoms, near vision, and overall satisfaction.

Complications of foldable intraocular lenses requiring explantation or secondary intervention--2000 survey update

A survey of the complications associated with foldable intraocular lenses (IOLs) that required explantation or secondary intervention was sent to members of the American Society of Cataract and Refractive Surgery and was also available to members of the European Society of Cataract and Refractive Surgeons. Preoperative data about visual acuity, patient signs and symptoms, and complications were assessed, and postoperative results and outcomes were analyzed. Complications and symptoms for each of the major groups of foldable IOLs explanted were tabulated separately: 3-piece monofocal silicone; 3-piece acrylic; 1-piece (plate-type) silicone; and multifocal silicone. A total of 259 surveys returned for evaluation. Accurate IOL power measurements as well as meticulous surgical technique, IOL loading and insertion, and proper patient counseling/selection remain the most important factors in avoiding complications with foldable IOLs.