Refractive Results after Implantation of a Light-Adjustable Intraocular Lens in Postrefractive Surgery Cataract Patients

Potential role of the light-adjustable lens in flanged intrascleral haptic fixation

PURPOSE

To compare maximum tensile strength between commonly used 3-piece intraocular lens (IOL) for flanged intrascleral haptic fixation (FISHF).

SETTING

Willis-Knight Eye Institute, Shreveport, Louisiana.

DESIGN

Laboratory investigation.

METHODS

Haptic tensile strength was compared with MA60AC, CT Lucia 602, AR40E, and the light-adjustable lens (LAL). Haptic strength with a 24-diopter (D) IOL was compared across all lenses, as well as across a range of 10 to 30 D with the MA60AC. A custom device was created to hold the IOL in correct haptic orientation. The maximum tension (mean ± SD) was recorded in Newtons (N) when the haptic lost tension or broke.

RESULTS

CT Lucia was the strongest at 1.53 ± 0.11 N vs 1.00 ± 0.15 (MA60AC), 0.87 ± 0.19 (AR40E), and 0.83 ± 0.14 N (LAL) ( P < .001). The LAL and AR40E were similar to a 9-0 polypropylene suture while being significantly stronger than 10-0 polypropylene suture ( P < .001). No difference in haptic tension for the MA60AC from 10 to 30 D ( P > .05). High magnification revealed the highest haptic fractures for MA60AC at 40% compared with LAL, AR40E, and CT Lucia at 0%. CT Lucia and AR40E had 100% of haptics disinserted from the IOL without any damage compared with 60% LAL and 60% MA60AC. CT Lucia, AR40E, and LAL have a flatter haptic angulation at 5 degrees.

CONCLUSIONS

Haptic strength, durability, and angulation of the LAL may support the possibility of FISHF in the hands of experienced surgeons. However, further testing is strongly recommended to verify whether physiologic conditions or light treatments may compromise long-term haptic stability.

An update on intraocular lens power calculations in eyes with previous laser refractive surgery

PURPOSE OF REVIEW

There is an ever-growing body of research regarding intraocular lens (IOL) power calculations following photorefractive keratectomy (PRK), laser-assisted in-situ keratomileusis (LASIK), and small-incision lenticule extraction (SMILE). This review intends to summarize recent data and offer updated recommendations.

RECENT FINDINGS

Postmyopic LASIK/PRK eyes have the best refractive outcomes when multiple methods are averaged, or when Barrett True-K is used. Posthyperopic LASIK/PRK eyes also seem to do best when Barrett True-K is used, but with more variable results. With both aforementioned methods, using measured total corneal power incrementally improves results. For post-SMILE eyes, the first nontheoretical data favors raytracing.

SUMMARY

Refractive outcomes after cataract surgery in eyes with prior laser refractive surgery are less accurate and more variable compared to virgin eyes. Surgeons may simplify their approach to IOL power calculations in postmyopic and posthyperopic LASIK/PRK by using Barrett True-K, and employing measured total corneal power when available. For post-SMILE eyes, ray tracing seems to work well, but lack of accessibility may hamper its adoption.

Cataract surgery following refractive surgery: Principles to achieve optical success and patient satisfaction

A growing number of patients with prior refractive surgery are now presenting for cataract surgery. Surgeons face a number of unique challenges in this patient population that tends to be highly motivated to retain or regain functional uncorrected acuity postoperatively. Primary challenges include recognition of the specific type of prior surgery, use of appropriate intraocular lens (IOL) power calculation formulas, matching IOL style with spherical aberration profile, the recognition of corneal imaging patterns that are and are not compatible with toric and/or presbyopia-correcting lens implantation, and surgical technique modifications, which are particularly relevant in eyes with prior radial keratotomy or phakic IOL implantation. Despite advancements in IOL power formulae, corneal imaging, and IOL options that have improved our ability to achieve targeted postoperative refractive outcomes, accuracy and predictability remain inferior to eyes that undergo cataract surgery without a history of corneal refractive surgery. Thus, preoperative evaluation of patients who will and will not be candidates for postoperative refractive surgical enhancements is also paramount. We provide an overview of the specific challenges in this population and offer evidence-based strategies and considerations for optimizing surgical outcomes.

Visual Outcomes of a Second-Generation, Enhanced UV Protected Light Adjustable Lens in Cataract Patients with Previous LASIK and/or PRK

Purpose

To report on the visual outcomes of the second-generation (ActivShieldTM) Light Adjustable Lens (LAL) used in cataract surgery for patients with a history of laser refractive surgery (LASIK and/or photorefractive keratectomy [PRK]) using a co-managed, open-access methodology.

Patients and Methods

This retrospective case series of consecutive patients with history of laser refractive surgery implanted with the second-generation LAL with an emmetropic target were included in the study. Following surgery, all patients received their ultraviolet (UV) light treatments at a separate open-access facility through a co-managed arrangement. Uncorrected distance visual acuity (UDVA), spherical equivalent (SE), and residual cylinder for eyes with an emmetropic refractive target were the primary outcome measures as documented at the patient's final, stable, refractive postoperative exam.

Results

Thirty-three patients (34 eyes) with a history of laser refractive surgery were included in the study and implanted with the second-generation LAL with a postoperative emmetropic refractive target. Twenty-eight (82.4%) saw 20/20 or better and 9 (26.5%) saw 20/15 or better. The mean SE was 0.01 ± 0.31 D and 33 (97.1%) were within ±0.50 D SE of plano. The mean residual cylinder was -0.28 ± 0.32 D and 30 (88.2%) were within ±0.50 D.

Conclusion

Use of the second-generation LAL was efficacious in cataract surgical patients with a history of LASIK and/or PRK using a co-managed, open-access methodology.

Refractive Outcomes of Cataract Surgery in Patients With Intrastromal Femtosecond Laser Treatment of Presbyopia (INTRACOR)

PURPOSE

To evaluate the outcomes of cataract surgery with intraocular lens (IOL) implantation in patients who underwent intrastromal femtosecond laser treatment of presbyopia (INTRACOR).

METHODS

This was an interventional case series of 8 patients (10 eyes) who presented for cataract surgery 6.1 ± 3.2 years (mean ± standard deviation [SD]) after INTRACOR (Technolas Perfect Vision GmbH) treatment. A monofocal IOL was implanted in 9 eyes (7 patients) and a small-aperture IOL was implanted in 1 eye. The IOL power was calculated without adjustments using biometry obtained after the INTRACOR treatment. For additional calculations, keratometry obtained before the INTRACOR treatment was used. Postoperative examinations included visual acuity testing, manifest refraction, defocus curve, ocular biometry, corneal tomography, aberrometry, anterior segment optical coherence tomography, and slit-lamp examination.

RESULTS

After the cataract surgery, the mean ± SD uncorrected distance visual acuity was 0.37 ± 0.17 logMAR, the corrected distance visual acuity was 0.10 ± 0.10 logMAR, and the manifest refraction spherical equivalent, adjusted to infinity, was +0.39 ± 0.63 diopters (D). Intermediate and near visual acuity, both uncorrected and distance-corrected, and distance-corrected defocus curves varied considerably among patients. Using biometry performed after INTRACOR, the traditional IOL power calculation formulas produced hyperopic outcomes, with the mean ± SD prediction error ranging from +0.72 ± 0.34 to +0.96 ± 0.41 D. Although the mean ± SD prediction error decreased (range: -0.34 ± 0.56 to -0.15 ± 0.53 D) when using keratometry obtained before INTRACOR, the accuracy remained low due to high variability.

CONCLUSIONS

In patients with cataract who had previous INTRACOR treatment, IOL power calculation could be inaccurate, with a tendency toward hyperopic outcomes. These results require confirmation in more extensive studies. [J Refract Surg. 2023;39(10):676-682.].

Comparing Visual Outcomes of Light Adjustable Intraocular Lenses in Patients With and Without Prior History of Corneal Refractive Surgery

PURPOSE

To assess visual outcomes of light adjustable intraocular lens (LAL; Calhoun Vision, Inc) implantation after cataract extraction in patients with a history of corneal refractive surgery.

METHODS

The records of patients who received LALs with and without a history of corneal refractive surgery were retrospectively reviewed. Data for 51 eyes (30 patients) with a history of corneal refractive surgery and 52 eyes (44 patients) without refractive surgery were analyzed. A total of 36 eyes of patients with and 43 eyes of patients without a history of corneal refractive surgery had 12-month follow-up data available. The primary outcomes evaluated were uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA).

RESULTS

At 12 months, 31% of eyes with a history of corneal refractive surgery had a UDVA of 20/20 or better and 97% of eyes were 20/40 or better. In contrast, 63% of patients with no history of corneal refractive surgery had 20/20 UDVA or better at 12 months and 100% were 20/40 or better. Of patients with a history of corneal refractive surgery, 55% and 83% of eyes at 12 months were within ±0.50 and ±1.00 diopters, respectively, of the target refraction compared to 89% and 96% of eyes without a history of corneal refractive surgery.

CONCLUSIONS

LALs are a promising platform for achieving excellent visual outcomes following cataract surgery. Patients with a prior history of corneal refractive surgery can achieve excellent visual outcomes with the LAL. However, this study found that patients with a history of corneal refractive surgery demonstrated less predictable visual acuity outcomes when compared to patients without a history of corneal refractive surgery. [J Refract Surg. 2023;39(5):311-318.].

Light adjustable intraocular lenses: an updated platform for cataract surgery

PURPOSE OF REVIEW

Light adjustable intraocular lenses (LALs) are a relatively new platform for cataract surgery that is shifting the paradigm for intraocular lens placement following cataract removal.

RECENT FINDINGS

LALs may have additional utility in patients with prior refractive surgery and complex ocular conditions, as they give the surgeon greater latitude in preoperative intraocular power calculations to meet postoperative refractive goals.

SUMMARY

Further study of best candidates for LALs is warranted. Current best candidates are patients who can comply with treatment and have decreased accuracy in calculating the preoperative intraocular power requirement.

Visual Outcomes of an Enhanced UV Protected Light Adjustable Lens Using a Novel Co-Managed, Open-Access Methodology

Purpose

To report on the safety and visual acuity (VA) outcomes using a co-managed, open-access methodology with a second-generation (ActivShield^TM) Light Adjustable Lens (LAL 2.0).

Patients and Methods

This retrospective observational case series of consecutive patients implanted with the LAL 2.0 choosing an emmetropic target in at least one eye were included in the study. All patients were co-managed with light treatments occurring at an open-access facility. Exclusion criteria included pathology of the macula and/or cornea with reduced best corrected visual acuity (BCVA). The primary outcome measures were uncorrected distance visual acuity (UDVA), spherical equivalent (SE), and residual cylinder for emmetropic goal eyes at the final 3- to 9-month postoperative visit.

Results

Thirty-three patients (62 eyes) were included in the study and implanted with the LAL 2.0. Thirty-three (53.2%) eyes had previous corneal refractive treatment(s) with 22 (66.7%) having no original historical refractive records available. Thirty-six (58.1%) total eyes and 20 (32.3%) postrefractive eyes had an emmetropic refractive target. Of all the emmetropic goal eyes, 35 (97.2%) saw 20/20 or better and 36 (100%) were within ±0.50 D SE of plano and had a mean cylinder of −0.15 ± 0.26 D. Of the postrefractive emmetropic goal eyes, 19 (95%) saw 20/20 or better, 20 (100%) were within ±0.50 D SE of plano and had a mean cylinder of −0.17 ± 0.28 D.

Conclusion

A co-managed, open-access methodology using the LAL 2.0 was safe and efficacious even in challenging postrefractive clinical scenarios.

Intraocular lens power calculation after radical keratotomy and photorefractive keratectomy: A case report

RATIONALE

To report a rare case of calculating the IOL power in a cataract patient who underwent both radial keratotomy (RK) and photorefractive keratectomy (PRK).

PATIENT CONCERNS

A 48-year-old woman underwent bilateral RK at age 22 and bilateral PRK at age 46. She developed bilateral corneal haze and corneal endothelial inflammation and received steroids therapy for long time after PRK. Then she was referred to our hospital due to decreased vision in the both eyes.

DIAGNOSES

The patient was diagnosed with binocular complicated cataract, corneal haze, high myopia and post corneal refractive surgery (RK and PRK).

INTERVENTIONS

The patient underwent bilateral phacoemulsification. The IOL power was calculated using SRK/T formula for RK and Haigis-L formula for PRK, respectively. We finally selected the Haigis-L formula and the intraocular lens (SN60WF) was implanted within the capsular bag.

OUTCOMES

After the surgery, both eyes showed myopia drift, and the right eye continuously fluctuated in refractive results. However, by nearly 1 year later, refractive results in both eyes had stabilized, and no other complications had occurred.

LESSONS

IOL power in patients who undergo both RK and PRK can be reliably calculated using the Shammas-PL, Average of multiple formulas, or Barret True-K No History formulas. Haigis-L formula is not suitable. Such patients require at least three months after surgery to attain refractive stability in both eyes.

Intraocular lens power calculations in eyes with previous corneal refractive surgery: Challenges, approaches, and outcomes

In eyes with previous corneal refractive surgery, difficulties in accurately determining corneal refractive power and in predicting the effective lens position create challenges in intraocular lens (IOL) power calculations. There are three categories of methods proposed based on the use of historical data acquired prior to the corneal refractive surgery. The American Society of Cataract and Refractive Surgery postrefractive IOL calculator incorporates many commonly used methods. Accuracy of refractive prediction errors within ± 0.5 D is achieved in 0% to 85% of eyes with previous myopic LASIK/photorefractive keratectomy (PRK), 38.1% to 71.9% of eyes with prior hyperopic LASIK/PRK, and 29% to 87.5% of eyes with previous radial keratotomy. IOLs with negative spherical aberration (SA) may reduce the positive corneal SA induced by myopic correction, and IOLs with zero SA best match corneal SA in eyes with prior hyperopic correction. Toric, extended-depth-of-focus, and multifocal IOLs may provide excellent outcomes in selected cases that meet certain corneal topographic criteria. Further advances are needed to improve the accuracy of IOL power calculation in eyes with previous corneal refractive surgery.

Use of presbyopia-correcting intraocular lenses in patients with prior corneal refractive surgery

PURPOSE OF REVIEW

Corneal refractive surgery has achieved spectacle-free vision for millions of patients, but this aging population is now developing cataracts. Many of these patients may wish to avoid reliance on glasses after cataract surgery. Presbyopia-correcting intraocular lenses (IOLs) offer a solution, but corneal changes after refractive surgery may compound higher order aberrations and dysphotopic symptoms associated with these IOLs. This review aims to discuss potential factors that could aid in determining suitable postkeratorefractive candidates for presbyopia-correcting IOLs.

RECENT FINDINGS

Studies investigating which preoperative measures influence outcomes are lacking. The few studies that have examined presbyopia-correcting IOLs in postkeratorefractive patients report that satisfactory outcomes are possible. However, recommendations for preoperative thresholds appear limited to expert opinion and studies involving virgin corneas.

SUMMARY

As the number of presbyopia-correcting IOLs and postkeratorefractive patients grows, continued investigation into relevant preoperative factors and appropriate IOLs is required to make evidence-based decisions. The current literature shows that with rigorous counseling and appropriate patient selection, presbyopia-correcting IOLs can provide postkeratorefractive patients with satisfactory results and spectacle independence. In addition, the development of postoperative modifiable IOLs may prove to be the preferred option.

Future Intraocular Lens Technologies

The future of intraocular lens (IOL) technology has already begun with a number of recent innovations. The postoperative change of refractive power will lead to a customized fine-tuning that provides patients with the individual vision they expect and with as much spectacle independence as possible. The latest-generation (2.0) Light-Adjustable Lens (RxSight) was recently introduced into clinical practice, with the first results being very encouraging. Other methods of altering the power of an already implanted IOL are under development. The same can be said about the correction of presbyopia, the so-called last frontier in refractive surgery. Extended depth-of-focus IOLs have been introduced, as has the technology of the pinhole IOL. The latter has therapeutic potential beyond the refractive aspect and has already proven helpful in cases of iris defects and irregular corneas. Several technologies are currently being tested to achieve-finally-an accommodative IOL. One such concept uses the (remaining) strength of the ciliary muscle, whereas another is triggered by the pupil reaction when shifting focus from far to near. Not an IOL itself, but rather a high-tech innovation that so far has mostly been implanted during cataract surgery, is a microelectronic sensor that measures habitual intraocular pressure (IOP) at any given time and promises to revolutionize the management of glaucoma patients. The last generation of this device (Eyemate; Implandata Opthalmics Products GmbH) is implanted during small-incision cataract surgery; the latest development is an even smaller sensor that will be inserted suprachoroidally before, in the near future, such a device will be part of a capsular ring. These IOP sensors are a prime example that IOL technology will continue to be a driving force in ophthalmology, with a positive impact far beyond cataract surgery.

Handling regular and irregular astigmatism during cataract surgery

PURPOSE OF REVIEW

There are several different approaches to handling regular and irregular astigmatism during cataract surgery, but still much debate on which solutions are most effective given unique patient circumstances. In this review, we examine recent literature and studies to highlight some of the most effective ways to plan preoperatively, manage regular and irregular astigmatism during cataract surgery, as well as managing postoperative complications.

RECENT FINDINGS

Recent developments in technology have provided increased courses of action for astigmatism management during cataract surgery. Additional options of toric IOLs with presbyopic platforms, light adjustable lenses, intraocular pinhole lenses, online technological tools and platforms, wavefront or topographic laser technology, and phototherapeutic keratectomy are all effective solutions to managing regular and irregular astigmatism. In this review, we will explore optimal approaches for unique situations.

SUMMARY

With increased technology, research, and methods, correcting regular and irregular astigmatism during cataract surgery is achievable in most patients. With in-depth preoperative planning, analysis of patient-specific factors, and a tailored approach, surgeons can obtain excellent uncorrected vision for patients.

Disruptive Innovation and Refractive IOLs: How the Game Will Change With Adjustable IOLs

The light-adjustable lens is the first Food and Drug Administration (FDA)-approved product from an entirely new category of intraocular lenses (IOLs). The 3-piece foldable silicone light-adjustable lens is implanted through a small incision after phacoemulsification. A slit-lamp-based digital light delivery device is used to adjust and then lock-in the IOL power during the first postoperative month. Up to 4.5 diopters (D) of cylindrical or spherical adjustment can be achieved. This should offer significant advantages in difficult IOL power calculation cases, such as postrefractive eyes. In addition to achieving better refractive accuracy, an adjustable IOL will now allow patients to test and elect a different refractive target postoperatively. This paradigm shift will change how cataract patients choose their refractive objectives, and how ophthalmologists will be able to achieve them. For example, adjustable IOLs may increase the popularity of pseudophakic monovision and bilateral same-day sequential surgery. For those electing adjustable IOL, preoperative patient counseling will change and certain pre- and intraoperative technologies, such as intraoperative aberrometry and digital astigmatic axis marking, would become superfluous.

Astigmatic correction with implantation of a light adjustable vs monofocal lens: a single site analysis of a randomized controlled trial

AIM

To evaluate the light adjustable lens (LAL) vs a standard monofocal lens in achieving target astigmatic refraction and improving postoperative uncorrected distance visual acuity (UDVA).

METHODS

This randomized controlled clinical trial included 40 patients with pre-existing astigmatism and visually significant cataract. Twenty-eight patients received the LAL and 12 control patients received a monofocal intraocular lens (IOL) after cataract extraction at a single institution. The patients with the LAL underwent adjustment by ultraviolet (UV) light postoperatively plus subsequent lock-in procedures and all patients returned to clinic for follow up of study parameters at 6, 9, and 12mo. Manifest refraction, distance visual acuity, and adverse events were recorded at each visit.

RESULTS

The mean cylinder before adjustment in eyes with the LAL was -0.89±0.58 D (-2.00 to 0.00 D) and -0.34±0.34 D (-1.25 to 0.00 D) after lock-in (P=1.68x10^-8). The mean cylinder in patients with the monofocal lens was -1.00±0.32 D (-1.50 to -0.50 D) at 17-21d postoperatively, which was statistically different from the LAL cylinder post lock-in (P=1.43x10^-6). UDVA in the LAL group was 20/20 or better in 79% of patients post lock-in with good stability over 12mo compared with 33% of the control patients with UDVA of 20/20 or better.

CONCLUSION

These results demonstrate that the LAL is more effective in achieving target refractions and improving postoperative UDVA in patients with pre-existing corneal astigmatism than a standard monofocal lens.

Supplementary IOLs: Monofocal and Multifocal, Their Applications and Limitations

Supplemental intraocular lenses (IOLs) have been developed to replace IOLs designed for in-the-bag placement being used as "piggy-back" IOLs in the sulcus due to unacceptable complications. The new IOLs have unique platform designs to avoid these complications. As a result, a new nomenclature is needed to describe the 4 scenarios when supplemental IOL use is now indicated.

Adjustable intraocular lens power technology

We present an overview of the adjustable intraocular lens (IOL) technologies that are available or under development. This includes IOL technologies that can be adjusted using secondary surgical procedures, such as the multicomponent IOL, the mechanically adjustable IOL, and the repeatedly adjustable IOL; IOLs that can be adjusted noninvasively in the postoperative setting, such as the magnetically adjustable IOL, the liquid crystal IOLs with wireless control; and IOLs that can be adjusted using the femtosecond laser or 2-photon chemistry. Finally, we discuss the preclinical and clinical studies of the light-adjustable intraocular lens (LAL) that is available commercially in Europe and Mexico and in the final stages of clinical evaluation in the United States. The general principles of each technology, as well as their research status, are described.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Corrective Techniques and Future Directions for Treatment of Residual Refractive Error Following Cataract Surgery

Postoperative residual refractive error following cataract surgery is not an uncommon occurrence for a large proportion of modern-day patients. Residual refractive errors can be broadly classified into 3 main categories: myopic, hyperopic, and astigmatic. The degree to which a residual refractive error adversely affects a patient is dependent on the magnitude of the error, as well as the specific type of intraocular lens the patient possesses. There are a variety of strategies for resolving residual refractive errors that must be individualized for each specific patient scenario. In this review, the authors discuss contemporary methods for rectification of residual refractive error, along with their respective indications/contraindications, and efficacies.

Developments in the correction of presbyopia II: surgical approaches

PURPOSE

To discuss the various static and dynamic surgical approaches which attempt to give presbyopes good vision at far, intermediate and near viewing distances.

CONTENT

Static methods broadly adopt the same optical techniques as those used in presbyopic contact lens correction and aim to satisfy the needs of the presbyope by increasing binocular depth-of-focus, often using monovision as well as simultaneous-imagery. Dynamic methods generally attempt to make use of at least some of the still-active elements of the accommodation system. They include procedures which are supposed to modify the relative geometry of the ciliary muscle and lens, or which reduce the stiffness of the presbyopic lens either by replacing it with other natural or man-made material or by subjecting it to femtosecond laser treatment. Alternatively the natural lens may be replaced by some form of intraocular lens which changes power as a result of forces derived from the still-active ciliary muscle, zonule and capsule, or other sources.

CONCLUSIONS

At present, multifocal intraocular lenses appear to offer the most consistent and reliable surgical approach to surgical presbyopic correction. They have obvious advantages in convenience and stability over optically-similar, simultaneous-image presbyopic contact lenses but this must be balanced against their relative inflexibility in cases of patient dissatisfaction. Dynamic methods remain largely experimental. Although some approaches show promise, as yet no method has demonstrated a reliable, long-term ability to correct distance refractive error and to appropriately change ocular power in response to changes in viewing distance over the normal range of interest.