Refractive lensectomy to correct ametropia

Refractive Lens Exchange: A Review

In recent decades, technical advancements in lens surgery have considerably improved safety and refractive outcomes. This has led to a much broader range of indications for refractive lens exchange (RLE). Effective restoration of uncorrected distance and near visual acuity is possible with modern presbyopia correcting intraocular lenses (IOLs). Hyperopic patients who are fully presbyopic were identified as ideal candidates for RLE. For myopic patients, an increased risk of retinal detachment has been reported, which leads to a higher threshold to perform RLE in this patient group. The most frequent postoperative complications include posterior capsular opacification, deviation from the target refraction and cystoid macular edema. Thus, adequate planning of surgery, careful patient selection, as well as comprehensive counseling are crucial for successful RLE.

Refractive lens exchange: What are the red lines?

Practical advancements in phacoemulsification techniques and intraocular lenses and the wide availability of phacoemulsification machines have led refractive lens exchange (RLE) to increase in popularity. Ethical boundaries in RLE have subsequently been pushed to include patients at higher risk of complications. In this editorial, we consider RLE outcomes and complications per type of refractive error, together with preoperative, intraoperative and postoperative ethical obligations for refractive surgeons. In the conclusions section, we propose an algorithm for ethics-guided indications to RLE.

Retinal detachment after refractive lens exchange: A narrative review

Refractive lens exchange (RLE) allows to correct ametropias and presbyopia by replacing the crystalline lens with an extended depth of focus or multifocal intraocular lens (IOL). Retinal detachment (RD) is one of the most serious adverse events after RLE. This study aimed to review the evidence related to the risk of RD after RLE and clinical outcomes. A search using PubMed and a snowball search approach was conducted to identify articles and case reports. According to the literature, the risks of RD should be considered in patients <60 years old with axial lengths >23 mm. Only nine articles reported visual acuity (VA) after RD in RLE, and only 25% of eyes had a VA > 20/40. Considering that the decrease in VA might be uniform for all types of IOLs after RD, surgeons should focus on selecting the patient to prevent RD rather than on a particular IOL optical design based on the potential risk of DR.

Refractive Results: Safety and Efficacy of Secondary Piggyback Sensar™ AR40 Intraocular Lens Implantation to Correct Pseudophakic Refractive Error

In this study we evaluate the visual outcomes, safety, efficacy, and stability of implanting of second sulcus intraocular lens (IOL) to correct unsatisfied ametropic patients after phacoemulsification. Methods. Retrospective study of 15 eyes (15 patients) underwent secondary intraocular lens implanted into the ciliary sulcus. The IOL used was a Sensar IOL three-piece foldable hydrophobic acrylic IOL. The first IOL in all patients was acrylic intrabagal IOL implanted in uncomplicated phacoemulsification surgery. Results. Fifteen eyes (15 patients) were involved in this study. Preoperatively, mean log⁡MAR UDVA and CDVA were 0.88 ± 0.22 and 0.19 ± 0.13, respectively, with a mean follow-up of 28 months (range: 24 to 36 months). At the end of the follow-up, all eyes achieved log⁡MAR UDVA of 0.20 ± 0.12 with postoperative refraction ranging from 0.00 to −0.50 D of attempted emmetropia. Conclusions. Implantation of the second sulcus SensarAR40 IOL was found to be safe, easy, and simple technique for management of ametropia following uncomplicated phacoemulsification.

Surgical options for correction of refractive error following cataract surgery

Refractive errors are frequently found following cataract surgery and refractive lens exchange. Accurate biometric analysis, selection and calculation of the adequate intraocular lens (IOL) and modern techniques for cataract surgery all contribute to achieving the goal of cataract surgery as a refractive procedure with no refractive error. However, in spite of all these advances, residual refractive error still occasionally occurs after cataract surgery and laser in situ keratomileusis (LASIK) can be considered the most accurate method for its correction. Lens-based procedures, such as IOL exchange or piggyback lens implantation are also possible alternatives especially in cases with extreme ametropia, corneal abnormalities, or in situations where excimer laser is unavailable. In our review, we have found that piggyback IOL is safer and more accurate than IOL exchange. Our aim is to provide a review of the recent literature regarding target refraction and residual refractive error in cataract surgery.

Management of residual refractive error after cataract surgery

PURPOSE OF REVIEW

To provide a review of the recent literature on the management of residual refractive error after cataract surgery.

RECENT FINDINGS

Laser in-situ keratomileusis (LASIK) is the most accurate procedure to correct residual refractive error after cataract surgery. Lens-based procedures, such as intraocular lens (IOL) exchange or piggyback lens implantation, are also possible alternatives in cases with extreme ametropia, corneal abnormalities, or in situations where excimer laser is not available. In this review, we found that Piggyback IOL were safer and more accurate than IOL exchange.

SUMMARY

Emmetropia is our main target today in modern cataract surgery. Accurate biometric analysis, selection and calculation of the adequate IOL, and modern techniques for cataract surgery all help surgeons to move toward the goal of cataract surgery as a refractive procedure free from refractive error. However, in spite of all these inputs, residual refractive error still occasionally occurs after cataract surgery and LASIK seems to be the most accurate method for its correction.

Color perception with AcrySof Natural and AcrySof single-piece intraocular lenses under photopic and mesopic conditions

PURPOSE

To examine color perception in patients receiving bilateral implantation of an ultraviolet (UV) and blue-light filtering intraocular lens (IOL) (AcrySof Natural SN60AT, Alcon Laboratories Inc.) or a UV-only filtering IOL (AcrySof SA60AT) and to compare the results with those in a phakic group.

SETTING

Cincinnati, Ohio, USA.

METHODS

In this prospective study, age-matched subjects who passed the Ishihara test and had visual acuities of 20/25 or better were recruited. There were 2 pseudophakic groups (bilateral SN60AT or SA60AT IOLs) and 1 phakic group. The Farnsworth-Munsell (FM) 100-hue test was administered to each subject twice under different conditions. The phakic and AcrySof Natural SN60AT groups were tested under photopic and mesopic conditions. The SA60AT subjects were further divided into subgroups (with and without yellow clip-on lenses) and tested under photopic and mesopic conditions.

RESULTS

A 1-way analysis of variance (ANOVA) of the square-root-transformed total error score showed no statistical differences (P = .637) between the treatment groups. Similarly, a 1-way ANOVA of the red-green error score (P = .729) and blue-yellow error score (P = .484) indicated no statistically significant differences between the treatment groups. The ANOVA results of the FM 100-hue test under mesopic conditions showed that the total error score in the AcrySof Natural IOL group was significantly lower (P = .046) than in the phakic group. There were no between-group differences in error scores under mesopic conditions.

CONCLUSION

The FM 100-hue testing showed no difference in color perception between subjects with AcrySof Natural IOLs and those in an age-matched phakic control group or in those with a UV-only filtering AcrySof IOL with or without yellow clip-on lenses.

Refractive lens exchange for myopia: a new perspective?

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Pseudophakic retinal detachment

Pseudophakic retinal detachment is a rare, but potentially serious, complication of cataract surgery. The incidence of pseudophakic retinal detachment following current surgical techniques of cataract extraction, including extracapsular cataract extraction by nuclear expression and phacoemulsification, is lower than that found after intracapsular cataract extraction. The risk of pseudophakic retinal detachment appears to be increased in myopic patients, in those patients in whom vitreous loss had occurred at the time of cataract surgery, and in patients undergoing Nd:YAG posterior capsulotomy. Most cases present to the clinician when the macula is already detached and the central vision is affected. When evaluating patients with pseudophakic retinal detachment, the fundal view is often impaired by anterior or posterior capsular opacification, reflections related to the intraocular lens, or poor mydriasis. Scleral buckling, pneumatic retinopexy, and primary pars plana vitrectomy, with or without combined scleral buckling, are the surgical techniques used to treat pseudophakic retinal detachment. Anatomical success rates are high after vitreo-retinal surgery for pseudophakic retinal detachment, although a smaller proportion of patients recover good vision following surgery.

Analysis of elements of interlenticular opacification

PURPOSE

To report the histopathologic and ultrastructural features of three cases of interlenticular opacification (ILO) between piggyback intraocular lenses.

DESIGN

Interventional case series with clinicopathologic correlation.

METHODS

Three pairs of acrylic piggyback lenses were explanted due to decrease in visual acuity associated with ILO. Lenses were evaluated with gross and light microscopic examinations in all cases. The anterior lens in one case was examined with scanning electron microscopy and energy dispersive x-ray spectroscopy.

RESULTS

The material opacifying the interlenticular space was composed mostly of retained/regenerative cortical material in all cases. From the peripheral interface towards the central interface, the opacifying material changed as the interlenticular space was progressively narrower. The material attached to the peripheral interface, where the interlenticular space was wider, was very thick. At the midperipheral interface, the thick cortical material was broken into multiple globules due to liquefactive degeneration. At the paracentral zone, compression of the globules formed a flat, compact layer of an amorphous material. At the central interface (contact zone), almost no material could be found between the piggyback lenses.

CONCLUSIONS

Analyses of ILO cases where all the components of the opacifying material were in situ allowed us to confirm that the pathogenesis of this complication is similar to that of posterior capsule opacification; thus, careful removal of lens epithelial cells and cortical material is mandatory in piggyback implantation.

Accuracy and predictability of intraocular lens power calculation after laser in situ keratomileusis

PURPOSE

To study the accuracy and predictability of intraocular lens (IOL) power calculation in eyes that had laser in situ keratomileusis (LASIK).

SETTING

Gimbel Eye Centre, Calgary, Alberta, Canada.

METHODS

Refractive outcomes in 6 cataract surgery and lensectomy eyes after previous LASIK were analyzed retrospectively. Target refractions based on measured and refraction-derived keratometric values were compared with postoperative achieved refractions. Differences between target refractions calculated using 5 IOL formulas and 2 A-constants and achieved refractions were also compared.

RESULTS

The refractive error of IOL power calculation in postoperative LASIK eyes was significantly reduced when refraction-derived keratometric values were used for IOL power calculation. Persistent residual hyperopia still occurred in some cases; this was corrected by hyperopic LASIK. Refractive results appeared more accurate and predictable when the Holladay 2 or Binkhorst 2 formula was used for IOL power calculation.

CONCLUSION

Hyperopic error after cataract surgery in post-LASIK eyes was significantly reduced by using refraction-derived keratometric values for IOL power calculation. Persistent hyperopic error was corrected by hyperopic LASIK.