Refractive lens exchange versus phakic intraocular lenses

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.

Effectiveness of SMILE Combined with Micro-Monovision in Presbyopic Patients: A Pilot Study

Binocular summation along all defocus range after a micro-monovision procedure has scarcely been studied. The aim of this pilot study was to evaluate the efficacy of SMILE combined with different levels of micro-monovision in presbyopic patients and to assess the binocular summation effect on contrast sensitivity defocus curves (CSDC) at the 6-month follow-up. Efficacy was assessed on the basis of visual acuity (VA) and stereopsis at far, intermediate, and near distances. Patient-reported outcomes (PROs) and binocular CSDC were also evaluated. Six patients completed the study with a programmed median anisometropia of 0.81 Diopter. The median binocular uncorrected VA was better than 0 logMAR at the three evaluated distances, and stereopsis was not impaired in any patient, achieving a median of ≤119 arcsec at any distance. CSDC increased binocularly after surgery, significantly in the range of -2 to -3 D (p < 0.05). No clinically relevant changes were observed in PROs compared with the preoperative period, and all patients achieved spectacle independence at intermediate/near distance and were likely or very likely to undergo the same surgery. In conclusion, micro-monovision with SMILE could be an effective procedure, with results that might be comparable to other laser correction techniques specifically designed for presbyopia correction.

Near visual acuity and patient-reported outcomes in presbyopic patients after bilateral multifocal aspheric laser in situ keratomileusis excimer laser surgery

PURPOSE

To determine improvement of near visual acuity by bilateral multifocal aspheric laser in situ keratomileusis (LASIK) treatments in presbyopic patients.

SETTING

Goethe-University, Frankfurt, Germany.

DESIGN

Prospective, nonrandomized trial.

METHODS

Thirty presbyopic patients underwent LASIK treatment with a multifocal aspheric ablation profile using an excimer laser (PresbyMAX). The first 15 patients received a multifocal aspheric ablation profile combined with micromonovision. For the consecutive 15 patients, less depth of focus was included on the distance eye (hybrid). Outcome parameters were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected and distance-corrected intermediate visual acuities, uncorrected near visual acuity (UNVA), and distance-corrected near visual acuity (DCNVA); manifest refraction spherical equivalent; subjective quality of vision; and spectacle independence.

RESULTS

The data of 29 patients were analyzed and showed that binocular CDVA changed from -0.16 ± 0.10 logarithm of the minimum angle of resolution (logMAR) preoperatively to 0.05 ± 0.20 logMAR UDVA and -0.06 ± 0.14 logMAR CDVA (P = .000, P = .001) 1 year postoperatively. Near visual acuity improved from 0.47 ± 0.13 logMAR (DCNVA) and 0.48 ± 0.26 logMAR (UNVA) to 0.19 ± 0.19 logMAR (DCNVA, P < .001) and 0.05 ± 0.15 logMAR (UNVA, P < .001). The hybrid and the μ-monovision group did not differ statistically except for a better DCNVA in the µ-monovision patients (0.21 ± 0.15 logMAR vs 0.34 ± 0.17 logMAR, P = .034). Of the hybrid and µ-monovision patients, 21 (72%) and 12 (41%) had a binocular CDVA and UDVA of 20/20 or better, 8 patients (28%) lost 1 line, 3 (10%) lost 2 lines, 4 (14%) lost 3 lines, and 2 (7%) lost 4 lines of CDVA.

CONCLUSIONS

The PresbyMAX laser seemed to satisfy most of the patients, although they experienced a loss of CDVA. The gain of near visual acuity and therefore reported less need of spectacles seemed to compensate for this loss.

Posterior chamber phakic intraocular lens for the correction of presbyopia in highly myopic patients

PURPOSE

To report the initial experience with a new presbyopic phakic intraocular lens (pIOL) in the correction of high myopia and presbyopia.

SETTING

Gemini Eye Clinic, Zlin, Czech Republic.

DESIGN

Prospective cohort study.

METHODS

Presbyopic eyes with moderate to high myopia were implanted with a presbyopic posterior chamber pIOL (IPCL). The visual acuities at near and distance, endothelial cell density, and ocular condition were examined 1 week, 3 months, 1 year and 2 years postoperatively.

RESULTS

The mean uncorrected distance visual acuity improved significantly from 1.25 logarithm of the minimum angle of resolution (logMAR) (1.15 to 1.35 95% confidence interval [CI]) to 0.11 logMAR (95% CI, 0.03 to 0.17) (P < .0001). No eye lost 1 or more lines of corrected distance visual acuity. The mean distance refraction improved significantly from -6.9 diopters (D) (range -8.6 to -5.3 D) preoperatively to -0.35 D (range -0.55 to -0.15 D, P < .0001) with less than -0.5 D residual refraction in 11 of 17 eyes. Fifteen of 17 eyes had improved uncorrected near visual acuity to J1 (Jaeger chart) at the 2-year follow-up. The near addition at the 2-year follow-up decreased from preoperatively +1.26 D (range 0.19 to 2.34 D) to +0.39 D (range 0.18 to 0.60 D). The mean endothelial cell density was reduced from 2552 cells/mm (range 2421 to 2682 cells/mm) to 2299 cells/mm (range 2108 to 2490 cells/mm) after 2 years. All patients were subjectively satisfied with the outcomes.

CONCLUSIONS

The new pIOL provided good visual outcomes in near and far distances in an initial case series of patients.

Middle- and long-term results after iris-fixated phakic intraocular lens implantation in myopic and hyperopic patients: a meta-analysis

The iris-fixated phakic intraocular lens (pIOL) has been available for over 25 years. To provide a clear picture of outcomes and risks, for this systematic review and meta-analysis, the literature was searched for reports on middle- and long-term effects. The iris-fixated phakic intraocular lens (pIOL) has been available for over 25 years. To provide a clear picture of outcomes and risks, for this systematic review and meta-analysis, the literature was searched for reports on middle- and long-term effects of iris-fixated pIOLs on myopic and hyperopic eyes with a follow-up of at least 2 to 4 years. Visual and refractive results after implantation for correction of myopia are positive and the complication rate is low. Endothelial cell loss appears to be at an acceptable rate, although the range of endothelial cell change is too wide to draw firm conclusions. Care should be taken when considering an iris-fixated pIOL for hyperopic eyes because complication rates, particularly pigment dispersion, might be higher than those in myopic eyes. More well-designed, long-term studies are needed, especially in hyperopic eyes. The authors advocate for standardized reporting of refractive surgery data. Initiatives proposed by journal authors and editors to achieve uniformity should be supported.

Myopia

Myopia, also known as short-sightedness or near-sightedness, is a very common condition that typically starts in childhood. Severe forms of myopia (pathologic myopia) are associated with a risk of other associated ophthalmic problems. This disorder affects all populations and is reaching epidemic proportions in East Asia, although there are differences in prevalence between countries. Myopia is caused by both environmental and genetic risk factors. A range of myopia management and control strategies are available that can treat this condition, but it is clear that understanding the factors involved in delaying myopia onset and slowing its progression will be key to reducing the rapid rise in its global prevalence. To achieve this goal, improved data collection using wearable technology, in combination with collection and assessment of data on demographic, genetic and environmental risk factors and with artificial intelligence are needed. Improved public health strategies focusing on early detection or prevention combined with additional effective therapeutic interventions to limit myopia progression are also needed.

Review of current status of refractive lens exchange and role of dysfunctional lens index as its new indication

Advances in phacodynamics and intraocular lenses (IOLs) has given second life to clear lens extraction (CLE) or refractive lens exchange (RLE) in recent years for the treatment of patients with high degrees of myopia, hyperopia, and astigmatism who are unsuitable for laser surgery. Furthermore, presbyopia treatment with RLE supplemented with multifocal or accommodating IOLs gives the dual benefit of correcting refractive errors with eliminating the need for cataract surgery. RLE should be consistent and effective for a good refractive outcome along with safety during the surgical procedure and in the postoperative period. Therefore, proper patient selection and accurate preoperative protocols for IOL power calculations and selection are important along with an appropriate choice of surgical procedure. Dysfunctional lens index is a new objective tool that helps surgeon to aid in diagnosing, counseling, and educating patients with dysfunctional clear lens. In this article, we give a brief overview about the application of RLE for individuals with presbyopia and refractive errors like myopia, hyperopia, and astigmatism who are not suitable for laser correction.

Refractive surgery beyond 2020

Refractive surgery refers to any procedure that corrects or minimizes refractive errors. Today, refractive surgery has evolved beyond the traditional laser refractive surgery, embodied by the popular laser in situ keratomileusis or 'LASIK'. New keratorefractive techniques such as small incision lenticule extraction (SMILE) avoids corneal flap creation and uses a single laser device, while advances in surface ablation techniques have seen a resurgence in its popularity. Presbyopic treatment options have also expanded to include new ablation profiles, intracorneal implants, and phakic intraocular implants. With the improved safety and efficacy of refractive lens exchange, a wider variety of intraocular lens implants with advanced optics provide more options for refractive correction in carefully selected patients. In this review, we also discuss possible developments in refractive surgery beyond 2020, such as preoperative evaluation of refractive patients using machine learning and artificial intelligence, potential use of stromal lenticules harvested from SMILE for presbyopic treatments, and various advances in intraocular lens implants that may provide a closer to 'physiological correction' of refractive errors.

[Refractive surgery for children with developmental delay : Indications, techniques and results]

Visual stimulation and communication with the surroundings are crucial factors for childhood development. In children with intellectual disability the developmental delay can be exacerbated by visual impairment leading to visual autism. Uncorrected refractive error is one of the leading causes of visual impairment and spectacles are the gold standard for treatment. For some children with developmental delay or intellectual disability, the fitting and wearing of spectacles can be impossible due to severe craniofacial malformations, poor neck control or involuntary head movements. In these cases, if wearing contact lenses is also impossible the refractive error remains untreated and the child visually impaired. In certain situations cornea-based laser refractive surgery or lens-based refractive surgery can treat these refractive errors to enable better unaided visual acuity and therefore enhanced stimulation and integration of these developmentally delayed children. This article describes and discusses the indications, technical aspects and results of refractive surgery for children with developmental delay and intellectual disability.

Refractive surgery

Refractive surgery has evolved beyond laser refractive techniques over the past decade. Laser refractive surgery procedures (such as laser in-situ keratomileusis), surface ablation techniques (such as laser epithelial keratomileusis), and photorefractive keratectomy have now been established as fairly safe procedures that produce excellent visual outcomes for patients with low-to-moderate amounts of ametropia. Additionally, a broader selection of options are now available to treat a wider range of refractive errors. Small incision lenticule extraction uses a femtosecond laser to shape a refractive lenticule, which is removed through a small wound. The potential advantages of this procedure include greater tectonic strength and less dry eye. In the future, intracorneal implants could be used to treat hyperopia or presbyopia. Phakic intraocular implants and refractive lens exchange might be useful options in carefully selected patients for correcting high degrees of ametropia. Thus, physicians are now able to provide patients with the appropriate refractive corrective option based on the individual's risk-benefit profile.

Clear lens extraction for the management of primary angle closure glaucoma: surgical technique and refractive outcomes in the EAGLE cohort

BACKGROUND

To describe the surgical technique and refractive outcomes following clear lens extraction (CLE) in the Effectiveness, in Angle-closure Glaucoma, of Lens Extraction trial.

METHODS

Review of prospectively collected data from a multicentre, randomised controlled trial comparing CLE and laser peripheral iridotomy. Eligible participants were ≥50 years old and newly diagnosed with (1) primary angle closure (PAC) with intraocular pressure above 30 mm Hg or (2) PAC glaucoma. We report the postoperative corrected distance visual acuity (CDVA) and refractive outcomes at 12 and 36 months postoperatively for those who underwent CLE.

RESULTS

Of the 419 participants, 208 were randomised to CLE. Mean baseline CDVA was 77.9 (SD 12.4) letters and did not change significantly at 36 months when mean CDVA was 79.9 (SD 10.9) letters. Mean preoperative spherical equivalents were +1.7 (SD 2.3) and +0.08 (SD 0.95) diopters (D) at 36 months. Fifty-nine per cent and 85% eyes were within ±0.5D and ±1.0D of predicted refraction, respectively, at 36 months.

CONCLUSIONS

Mean CDVA in patients undergoing CLE for angle-closure glaucoma appeared stable over the 3-year study period. Refractive error was significantly reduced with surgery but refractive predictability was suboptimal.

TRIAL REGISTRATION NUMBER

Modern Phacoemulsification and Intraocular Lens Implantation (Refractive Lens Exchange) Is Safe and Effective in Treating High Myopia

Improved efficacy, predictability, and safety of modern phacoemulsification have resulted in cataract surgery being considered as a refractive procedure. Refractive lens exchange by definition is a surgery aimed at replacing the cataractous or clear crystalline lens with an intraocular lens (IOL) in cases of high ametropia. The excellent intraocular optics of this procedure provide a better visual outcome as compared with laser refractive surgery in high myopia. With advances in technology and IOL formulas, the predictability of refractive outcome after cataract surgery in high myopes has improved. The option of addressing presbyopia using multifocal/accommodating IOLs or monovision results in patients achieving reasonable spectacle independence. The most important concern with respect to phacoemulsification in high myopia is the risk of pseudophakic retinal detachment. High myopia is an independent risk factor for retinal detachment, and recent publications have reported a much lesser risk of retinal detachment specifically attributable to phacoemulsification in high myopes, especially if a thorough posterior segment evaluation is done and patients are followed up until development of complete posterior vitreous detachment. Refractive lens exchange is an effective and safe option to correct high myopia and can significantly improve quality of life in select patients.

Epidemiology and outcomes in refractive lens exchange surgery

PURPOSE

To assess demographics and refractive outcomes in patients undergoing refractive lens exchange surgery (RLE), with a population of cataract patients as a reference.

METHODS

A RLE cohort from a private eye clinic (n = 675) and a cataract cohort from the outcome registration of the Swedish National Cataract Register were studied and compared from an epidemiological perspective regarding age, gender, preoperative refraction and postoperative refractive outcome.

RESULTS

The RLE patients were younger (52.1 ± 7.7 versus 73.84 ± 9.32 years) with a smaller percentage of women (45.28% versus 60.46%; p < 0.001) and were more often myopic than the cataract patients. Astigmatism and hyperopia did not differ between the cohorts. Uncorrected visual acuity after RLE equalled the best corrected visual acuity in best cases after cataract surgery. The absolute biometry prediction was more accurate in RLE (0.17 ± 0.27 D versus 0.40 ± 0.58 D; p < 0.001), particularly in patients given a customized toric IOL (0.12 ± 0.27 D; p < 0.05). In cataracts, the Haigis' formula showed higher accuracy than the SRK/T formula (0.39 ± 0.53 D versus 0.43 ± 0.61 D; p < 0.01). Postoperatively after RLE, Laser Epithelial Keratomileusis was performed in 9.04% and Yttrium Aluminium Garnet capsulotomy in 7.41% of the eyes. Other reoperations were performed in three cases, and five postoperative retinal detachments occurred after RLE.

CONCLUSION

Compared with patients undergoing cataract surgery, we see many similarities, but also many interesting differences in patients undergoing RLE. Basic information about the growing population choosing to undergo RLE can help us plan future ophthalmic care.

Refractive lens exchange in modern practice: when and when not to do it?

Cataract surgery due to advances in small incision surgery evolved from a procedure concerned with the primary focus on the safe removal of cataractous lens to a procedure focused on the best possible postoperative refractive result. As the outcomes of cataract surgery became better, the use of lens surgery as a refractive modality in patients without cataracts has increased in interest and in popularity. Removal of the crystalline lens for refractive purposes or refractive lens exchange (RLE) presents several advantages over corneal refractive surgery. Patients with high degrees of myopia, hyperopia and astigmatism are still not good candidates for laser surgery. Moreover, presbyopia can currently only be corrected with monovision or reading spectacles.

RLE supplemented with multifocal or accommodating intraocular lenses (IOLs) in combination with corneal astigmatic procedures might address all refractive errors including presbyopia, and eliminate the future need for cataract surgery.

A paired comparison of intracameral mydriatics in refractive lens exchange surgery

PURPOSE

To compare the efficacy and intra-operative safety of intracameral mydriatics to topical mydriatics in patients undergoing refractive lens exchange (RLE) surgery.

METHODS

In a randomized intra-individually comparing study performed at Koskelas Eye Clinic, Luleå, and Department of Clinical Sciences/Ophthalmology, Umeå University Hospital, Umeå, Sweden, 56 patients undergoing same-day bilateral RLE were included. Pupils were randomly dilated with topical mydriatics in one eye and intracameral mydriatics in the fellow eye. Pupil sizes were recorded intra-operatively throughout the procedures. Perceived pain/discomfort and glare were assessed immediately postoperatively using a visual analogue scale from 0 to 10.

RESULTS

Topical mydriatics and intracameral mydriatics both give satisfactory pupil dilation in routine RLE. However, there was noticeable iris billowing in 17 eyes dilated with topical mydriatics but only one eye with intracameral mydriatics (p < 0.001). Pupils were initially slightly larger in the topical mydriatics group but contracted during surgery. There was no perceived difference with regards to glare, pain or discomfort between the treatments. The surgeon graded intracameral mydriatics eyes as easier to operate on.

CONCLUSION

Both topical mydriatics and intracameral mydriatics give satisfactory mydriasis for RLE, but pupil constriction and iris billowing are more pronounced with topical mydriatics.

Long-term refractive outcomes of posterior chamber phakic (spheric and toric implantable collamer lens) intraocular lens implantation

To report the long-term refractive outcomes, safety, predictability, efficacy and complications of 349 eyes treated with posterior chamber phakic intraocular lenses (pIOLs). A retrospective review of consecutive clinical cases of patients who underwent spheric implantable collamer lens (ICL) and toric ICL (TICL) implantation. The study included 349 eyes of 216 patients with sphere between +8 to −24 diopters (D) and 0 to −6.5 D of astigmatism. Statistical analysis was performed to identify differences between preoperative and postoperative refractive outcomes. Main outcome measures were preoperative and postoperative uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical and cylindrical errors and spherical equivalent and significant postoperative complications. 194 eyes were treated with TICL and 155 eyes with ICL. The mean age of the patients was 29 ± 6.7 years. The mean preoperative sphere was −10.35 ± 5.1 D (+8 to −24) and the postoperative sphere was −0.09 ± 1.06 D (+3.25 to −6.5), p < 0.001. Preoperative cylinder was −2.63 ± 1.44 (0 to −6.5 D) and postoperative cylinder was −0.97 ± 0.89 D (0 to −3.5), p < 0.001. The preoperative mean spherical equivalent was −11.6 ± 5.12 D (+7.875 to −25.625) and postoperative spherical equivalent was −0.52 ± 1.03 (+2.25 to −6.75), p < 0.001. The mean preoperative UDVA was 1.72 ± 0.49 and postoperative UDVA was 0.23 ± 0.22, p < 0.001. The mean preoperative CDVA was 0.21 ± 0.17 and postoperative CDVA was 0.12 ± 0.138, p < 0.001. The implantation of posterior chamber pIOLs is a safe, predictable and effective strategy to manage refractive errors during long-term follow-up.

Influence of anterior segment power on the scan path and RNFL thickness using SD-OCT

PURPOSE

Retinal nerve fiber layer (RNFL) thickness measures with spectral domain-optical coherence tomography (SD-OCT) provide important information on the health of the optic nerve. As with most retinal imaging technologies, ocular magnification characteristics of the eye must be considered for accurate analysis. While effects of axial length have been reported, the effects of anterior segment optical power on RNFL thickness measures have not been described fully to our knowledge. The purpose of our study was to determine the influence of the optical power change at the anterior corneal surface, using contact lenses, on the location of the scan path and measurements of RNFL thickness in normal healthy eyes.

METHODS

We recruited 15 normal subjects with less than 6 diopters (D) of ametropia and no ocular pathology. One eye of each subject was selected randomly for scanning. Baseline SD-OCT scans included raster cubes centered on the optic nerve and macula, and a standard 12-degree diameter RNFL scan. Standard 12-degree RNFL scans were repeated with 10 separate contact lenses, (Proclear daily, Omafilcon A/60%) ranging from +8 to -12 D in 2-D steps. The extent of the retinal scan, and RNFL thickness and area measures were quantified using custom MATLAB programs that included ocular biometry measures (IOL Master).

RESULTS

RNFL thickness decreased (0.52 μm/D, r = -0.33, P < 0.01) and the retinal region scanned increased (0.52%/D, r = 0.97, P < 0.01) with increase in contact lens power (-12 to +8). The normalized/percentage rates of change of RNFL thickness (-0.11/mm, r = -0.67, P < 0.01) and image size (0.11/mm, r = 0.96, P < 0.01) were related to axial length. Changes in the retinal region scanned were in agreement with transverse scaling, computed with a three surface schematic eye (R(2) = 0.97, P < 0.01). RNFL area measures, that incorporated the computed transverse scaling, were not related significantly to contact lens power (863 μm(2)/D, r = 0.06, P = 0.47).

CONCLUSIONS

Measurements of RNFL thickness by SD-OCT are dependent on the optics of the eye, including anterior segment power and axial length. The relationships between RNFL thickness measures and optical power are a direct reflection of scan path location with respect to the optic nerve head rim, caused by relative magnification. An incorporation of transverse scaling to RNFL area measures, based on individualized ocular biometry, eliminated the magnification effect.