BCLA CLEAR Presbyopia: Management with corneal techniques

Corneal techniques for enhancing near and intermediate vision to correct presbyopia include surgical and contact lens treatment modalities. Broad approaches used independently or in combination include correcting one eye for distant and the other for near or intermediate vision, (termed monovision or mini-monovision depending on the degree of anisometropia) and/or extending the eye's depth of focus [1]. This report reviews the evidence for the treatment profile, safety, and efficacy of the current range of corneal techniques for managing presbyopia. The visual needs and expectations of the patient, their ocular characteristics, and prior history of surgery are critical considerations for patient selection and preoperative evaluation. Contraindications to refractive surgery include unstable refraction, corneal abnormalities, inadequate corneal thickness for the proposed ablation depth, ocular and systemic co-morbidities, uncontrolled mental health issues and unrealistic patient expectations. Laser refractive options for monovision include surface/stromal ablation techniques and keratorefractive lenticule extraction. Alteration of spherical aberration and multifocal ablation profiles are the primary means for increasing ocular depth of focus, using surface and non-surface laser refractive techniques. Corneal inlays use either small aperture optics to increase depth of field or modify the anterior corneal curvature to induce corneal multifocality. In presbyopia correction by conductive keratoplasty, radiofrequency energy is applied to the mid-peripheral corneal stroma, leading to mid-peripheral corneal shrinkage and central corneal steepening. Hyperopic orthokeratology lens fitting can induce spherical aberration and correct some level of presbyopia. Postoperative management, and consideration of potential complications, varies according to technique applied and the time to restore corneal stability, but a minimum of 3 months of follow-up is recommended after corneal refractive procedures. Ongoing follow-up is important in orthokeratology and longer-term follow-up may be required in the event of late complications following corneal inlay surgery.

BCLA CLEAR Presbyopia: Evaluation and diagnosis

It is important to be able to measure the range of clear focus in clinical practice to advise on presbyopia correction techniques and to optimise the correction power. Both subjective and objective techniques are necessary: subjective techniques (such as patient reported outcome questionnaires and defocus curves) assess the impact of presbyopia on a patient and how the combination of residual objective accommodation and their natural DoF work for them; objective techniques (such as autorefraction, corneal topography and lens imaging) allow the clinician to understand how well a technique is working optically and whether it is the right choice or how adjustments can be made to optimise performance. Techniques to assess visual performance and adverse effects must be carefully conducted to gain a reliable end-point, considering the target size, contrast and illumination. Objective techniques are generally more reliable, can help to explain unexpected subjective results and imaging can be a powerful communication tool with patients. A clear diagnosis, excluding factors such as binocular vision issues or digital eye strain that can also cause similar symptoms, is critical for the patient to understand and adapt to presbyopia. Some corrective options are more permanent, such as implanted inlays / intraocular lenses or laser refractive surgery, so the optics can be trialled with contact lenses in advance (including differences between the eyes) to better communicate with the patient how the optics will work for them so they can make an informed choice.

IRIS® Registry (Intelligent Research In Sight) Analysis of the Incidence of Monovision in Cataract Patients with Bilateral Monofocal Intraocular Lens Implantation

Purpose

To determine the incidence of pseudophakic monovision among patients bilaterally implanted with monofocal intraocular lenses (IOLs) and to characterize the distribution of myopic offsets achieved.

Patients and Methods

This retrospective database study included data on patients receiving care from ophthalmologists who contributed to the Academy IRIS® (Intelligent Research In Sight) Registry. Anonymized data were collected, including patient age, ethnicity, procedure data (CPT code, date, laterality), and postoperative manifest refractive spherical equivalent (MRSE) in both eyes implanted with monofocal or monofocal toric IOLs. No data regarding IOL manufacturer, model, or power were collected. One primary outcome measure was the percentage of patients achieving monovision (defined as emmetropia within ±0.25 diopters [D] in one eye and a myopic offset of ≥0.50 D in the fellow eye) among all patients receiving bilateral monofocal IOLs at the time of cataract surgery between January 1, 2016, and September 1, 2019, with at least 90 days of follow-up. Other primary outcomes included the distribution and frequency of myopic offsets (anisometropia) between eyes.

Results

Of the 16,765 people receiving bilateral monofocal IOLs within the study period, 4796 (28.6%) achieved emmetropia in at least one eye, as defined by an MRSE within ± 0.25 D. The incidence of monovision among these patients was 34.2% (1638/4796). One-quarter (24.7%; 405/1638) of patients who achieved monovision had a myopic offset between 0.50 and 0.74 D, with more than one-third (35.2%; 576/1638) falling within 0.75-1.24 D and 18.0% within 1.25-1.74 D. A myopic offset ≥1.75 D was observed in 22.1% (362/1638) of patients who achieved monovision.

Conclusion

Pseudophakic monovision for presbyopia correction was achieved in ~34% of patients in the IRIS Registry bilaterally implanted with monofocal IOLs, with myopic offsets typically ranging from 0.5 to 1.24 D.

Pharmacological Treatment in Presbyopia

Pharmacological treatment of presbyopia may be an alternative for those who want a spectacle-free scenario and an easy-to-use method with lower risk of irreversible ocular adverse events. There are two main agents, miotics and lens softeners, investigated as agents for the pharmacological treatment. Miotic agents treat presbyopia by creating a pinhole effect which may increase the depth of focus at all working distances. The miotic agents have been studied for application to only one eye for monovision or both eyes. Their effect is temporary with common adverse events, such as headache and dim vision at nighttime, with no known long-term safety and efficacy. There have been studies on the miotic agents in combination with other agents for additive treatment effects or lessening adverse events, however, these combination effects are not clear. Lens softeners increase the elasticity of the lens, which is targeted at one of the etiologic mechanisms of presbyopia. There is only one lens softener being investigated in only a few trials. The results were inconclusive. The recent approval of 1.25% pilocarpine for treatment of presbyopia by the US FDA may be an important milestone for investigation of real-world data of pharmacological treatment of presbyopia.

Presbyopia Treatments by Mechanism of Action: A New Classification System Based on a Review of the Literature

Presbyopia, a loss of accommodative ability associated with aging, is a significant cause of vision impairment globally. At the clinical level, it is a frustrating and difficult issue that negatively impacts patients’ quality of life. Less appreciated is the fact that loss of accommodative ability and its current treatments methods may present safety concerns, for example, increasing the risk of falls. Therefore, a more complete understanding of treatment options with respect to how they relate to the natural ability of the eye is needed to improve decision making and to aid clinicians in individualizing treatment options. This article reviews the options for expanding functional through focus—a term coined to describe the ability of the eye to see at all distances with minimal latency—by how they vary the refractive power over time, across the visual field, between eyes, or across a range of distances.

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Correcting Presbyopia With Autofocusing Liquid-Lens Eyeglasses

OBJECTIVE

Presbyopia, an age-related ocular disorder, is characterized by the loss in the accommodative abilities of the human eye. Conventional methods of correcting presbyopia divide the field of view, thereby resulting in significant vision impairment. We demonstrate the design, assembly and evaluation of autofocusing eyeglasses for restoration of accommodation without dividing the field of view.

METHODS

The adaptive optics eyeglasses comprise of two variable-focus liquid lenses, a time-of-flight range sensor and low-power, dual microprocessor control electronics, housed within an ergonomic frame. Subject-specific accommodation deficiency models were utilized to demonstrate high-fidelity accommodative correction. The abilities of this system to reduce accommodation deficiency, its power consumption, response time, optical performance and MTF were evaluated.

RESULTS

Average corrected accommodation deficiencies for 5 subjects ranged from -0.021 D to 0.016 D. Each accommodation correction calculation was performed in ∼67 ms which consumed 4.86 mJ of energy. The optical resolution of the system was 10.5 cycles/degree, and featured a restorative accommodative range of 4.3 D. This system was capable of running for up to 19 hours between charge cycles and weighed ∼132 g.

CONCLUSION

The design, assembly and performance of an autofocusing eyeglasses system to restore accommodation in presbyopes has been demonstrated.

SIGNIFICANCE

The new autofocusing eyeglasses system presented in this article has the potential to restore pre-presbyopic levels of accommodation in subjects diagnosed with presbyopia.

Extended depth-of-focus technology in intraocular lenses

The extended depth-of-focus (EDOF) intraocular lens (IOL) is an emerging technology that is designed to improve range of vision, especially at intermediate distances. In this review, we describe the clinical performance of 4 emerging EDOF IOL technologies; that is, small aperture, bioanalogic, diffractive optics, and nondiffractive optical manipulations. The American Academy of Ophthalmology generated a consensus statement for EDOF IOLs that provided benchmarks and recommendations for classifying an implant as an EDOF IOL as well as standardized testing criteria for evaluating performance. Although many types of EDOF technologies are being developed, there are important differences in their performance that require further testing and evaluation.

Crossed versus conventional pseudophakic monovision for high myopic eyes: a prospective, randomized pilot study

BACKGROUND

Aiming at spectacle independence, conventional pseudophakic monovision has been widely used in myopia patients with bilateral monofocal intraocular lens implantation. However, the crossed monovision, which is to correct the dominant eye for near vision and the non-dominant eye for distant vision, has been mentioned preferable for high myopic cataract patients by some studies. We have conducted this study to compare clinical results to assess the feasibility of conventional and crossed monovision for high myopic pseudophakic patients by comparing patient satisfaction, visual function and spectacle independence.

METHOD

Forty-sixth high myopia patients were divided into two groups: 22 in crossed monovision group with patients whose refraction targeted to - 2.00 diopters (D) in the dominant eye and - 0.50D in the non-dominant eye; 24 in conventional monovision group with patients whose refraction targeted to - 0.50D in the dominant eye and - 2.00D in the non-dominant eye. Binocular uncorrected distance visual acuity (BUDVA), binocular uncorrected near visual acuity (BUNVA), binocular corrected distant visual acuity (BCDVA), binocular corrected near visual acuity (BCNVA), contrast visual acuity and stereoacuity were examined at postoperative 2 weeks, 1 month and 3 months. Questionnaires were completed by patients 3 months after binocular surgery to evaluate patients' satisfaction and spectacle independence.

RESULTS

The conventional monovision and the crossed monovision group showed no significant differences of mean BUDVA, BUNVA, BCDVA, BCNVA 2 weeks, 1 month or 3 months postoperatively (P > 0.05). There was no difference in the bilateral contrast sensitivity or stereoscopic function between the convention conventional and crossed monovision groups (P > 0.05). Patient satisfaction with near and distant vision, as well as spectacle dependence did not differ significantly between the two groups (P > 0.05).

CONCLUSION

Crossed pseudophakic monovision exhibited similar visual function when compared with conventional monovision technique, which indicates that it is an effective option to improve the visual functionality and quality of life for high myopic patients who considering bilateral cataract surgery.

TRIAL REGISTRATION

The Institutional Review Board and Ethics committee of the First Affiliated Hospital of Chongqing Medical University, Chongqing, China. The trial registration was submitted in September 2018 and passed on March 18, 2020, and the registration number is: ChiCTR2000030935 .

Monovision with a Bifocal Diffractive Multifocal Intraocular Lens in Presbyopic Patients: A Prospective, Observational Case Series

PURPOSE

We report the visual outcomes and patient satisfaction after bilateral implantation of a bifocal diffractive intraocular lens with monovision.

DESIGN

Prospective, observational case series.

METHODS

Twenty-one subjects underwent cataract surgery or refractive lens exchange with bilateral implantation of the ZMB00 intraocular lens, with the dominant eye and nondominant eye targeted for plano and -1.25 to -1.00 diopters, respectively. Postoperative assessments included visual acuity (VA) at various distances under photopic and mesopic conditions; defocus curve, contrast sensitivity, and stereopsis; and Visual Function Questionnaire-25 and supplementary questionnaire.

RESULTS

Mean binocular uncorrected VA at distance, intermediate (67 cm), and near (30 cm) were -0.03 ± 0.06, 0.12 ± 0.18, and 0.11 ± 0.05, respectively. No eyes lost >1 line of corrected distance VA. Binocular intermediate VA was significantly better in the uncorrected condition (P = .004) whereas binocular distance VA was better in the distance-corrected condition (P = .014). Near VA was similar in both conditions (P > .05). Stereoacuity and contrast sensitivity were within normal limits. All subjects had a composite score of ≥90 for vision-targeted items in the National Eye Institute Visual Function Questionnaire-25. Halos, glare, and starbursts occurred in 52%, 29%, and 24% of subjects, respectively. All subjects reported a satisfaction score of ≥3.5 of 5 and required no spectacles postoperatively. No intraocular lens exchange was required.

CONCLUSIONS

Monovision with bilateral bifocal multifocal intraocular lens was safe and provided satisfactory vision at various distances, with good stereopsis and contrast sensitivity. Complete spectacle independence and high satisfaction score were achieved. In comparison with bilateral emmetropic bifocal multifocal intraocular lens, it provided better vision at intermediate and at very near distances without inducing more dysphotopsia.

Varifocal Versus Monofocal LASIK in Presbyopic Hyperopic Eyes

PURPOSE

To compare varifocal (SupraCor; Technolas Perfect Vision GmbH, Munich, Germany) to monofocal (Zyoptix TissueSaving; Bausch & Lomb, Rochester, NY) LASIK in patients with hyperopic presbyopia.

METHODS

In this prospective, non-randomized, comparative case series, consecutive patients with hyperopia, presbyopia, and emmetropia as target refraction were bilaterally treated with varifocal (8 patients) or monofocal (7 patients) LASIK. The study was designed for 35 patients, but was terminated early after interim analysis. Outcomes (preoperative and 1 day, 1 week, 1 month, and 3 months postoperative) were: monocular and binocular uncorrected near visual acuity (UNVA), distance-corrected near visual acuity (DCNVA), uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), low-contrast UDVA and CDVA, efficacy, and safety.

RESULTS

Preoperative data were similar in both groups. Monocular and binocular UNVA were not significantly different between both groups at any follow-up visit. At 3 months, mean monocular UNVA was 0.40 logMAR in both groups. Monocular DCNVA and binocular CDVA were not significantly different between groups. Monocular mean CDVA was 0.00 ± 0.06 logMAR after varifocal LASIK and -0.06 ± 0.04 logMAR after monofocal LASIK. The efficacy index was 0.9 after vari-focal LASIK and 0.88 after monofocal LASIK (not significant). The safety index was 1.08 after varifocal LASIK and 1.125 after monofocal LASIK (not significant).

CONCLUSIONS

With emmetropia as target refraction, varifocal ablations yielded no additional benefit compared to monofocal ablations in hyperopic presbyopic LASIK. The authors speculate that epithelial remodeling masks the impact of a varifocal ablation pattern and that a myopic postoperative refraction (modified monovision) may be necessary to further improve near and intermediate vision. These results demonstrate the value of a control group in studies evaluating presbyopia corrections. [J Refract Surg. 2019;35(7):459-466.].

Spectacle Independence And Patient Satisfaction With Pseudophakic Mini-Monovision Using Aberration-Free Intraocular Lens

Purpose

To assess spectacle independence and patient satisfaction with pseudophakic mini-monovision in patients undergoing routine bilateral cataract surgery with implantation of an aspherical aberration-free intraocular lens (Akreos AO, Bausch and Lomb, USA).

Methods

This study was a retrospective analysis that included 60 eyes of 30 consecutive patients between 2016 and 2018. The included patients had undergone sequential bilateral routine phacoemulsification after choosing the mini-monovision option. Test for ocular dominance was done using a sighting test. Emmetropia was aimed at in the dominant eye, while in the non-dominant eye the aim was myopia between -1 D and -1.5 D. The main outcome parameters were uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), and data reported from a questionnaire given to the patients at 3 months postoperative visit.

Results

The study included 60 eyes of 30 consecutive patients. The mean binocular UDVA was 0.09 ± 0.07 logMAR. Twenty-eight patients (93%) had binocular UDVA of 0.2 logMAR or better. The mean binocular uncorrected intermediate distance visual acuity (at 65 cm) was 0.16 ± 0.12 logMAR. Twenty-six patients (87%) had binocular uncorrected intermediate distance visual acuity of 0.2 logMAR or better. The mean binocular UNVA (at 35 cm) was 0.30 ± 0.21 logMAR. Fourteen patients (47%) had binocular UNVA of 0.2 logMAR or better. The patients score in the questionnaire was significantly higher in far and intermediate vision than near vision (p = 0.022). The patients score was significantly higher in day vision than night vision (p = 0.031). The mean overall patient satisfaction was good (9.1 ± 1.54). Twenty-eight patients (93%) reported high spectacle independence for far vision (score 8, 9, or 10).

Conclusion

Pseudophakic mini-monovision shows good results for spectacle independence and high patient satisfaction. It is a safe and inexpensive option after bilateral cataract surgery for correcting distance and intermediate vision. However, it might show lower results with near and night vision which is generally acceptable. Using aberration-free monofocal IOL allows for the residual normal positive corneal aberration that may augment the effect of monovision.

Presbyopia: Effectiveness of correction strategies

Presbyopia is a global problem affecting over a billion people worldwide. The prevalence of unmanaged presbyopia is as high as 50% of those over 50 years of age in developing world populations, due to a lack of awareness and accessibility to affordable treatment, and is even as high as 34% in developed countries. Definitions of presbyopia are inconsistent and varied, so we propose a redefinition that states "presbyopia occurs when the physiologically normal age-related reduction in the eye's focusing range reaches a point, when optimally corrected for distance vision, that the clarity of vision at near is insufficient to satisfy an individual's requirements". Strategies for correcting presbyopia include separate optical devices located in front of the visual system (reading glasses) or a change in the direction of gaze to view through optical zones of different optical powers (bifocal, trifocal or progressive addition spectacle lenses), monovision (with contact lenses, intraocular lenses, laser refractive surgery and corneal collagen shrinkage), simultaneous images (with contact lenses, intraocular lenses and corneal inlays), pinhole depth of focus expansion (with intraocular lenses, corneal inlays and pharmaceuticals), crystalline lens softening (with lasers or pharmaceuticals) or restored dynamics (with 'accommodating' intraocular lenses, scleral expansion techniques and ciliary muscle electrostimulation); these strategies may be applied differently to the two eyes to optimise the range of clear focus for an individual's task requirements and minimise adverse visual effects. However, none fully overcome presbyopia in all patients. While the restoration of natural accommodation or an equivalent remains elusive, guidance is given on presbyopic correction evaluation techniques.

Monovision LASIK in emmetropic presbyopic patients

Background

To evaluate the efficacy and patient satisfaction of laser in situ keratomileusis (LASIK) monovision correction in presbyopic emmetropic patients.

Methods

A retrospective review of 294 patients who underwent LASIK for monovision was conducted. All patients had preoperative uncorrected distance visual acuity in each eye of 20/25 or better in both eyes and underwent primary LASIK treatment in one eye with a near target; 82 patients underwent surgery in the distant eye for hypermetropia. Patients completed a patient-reported-outcome questionnaire at their one-month postoperative visit. Analysis was performed on a per patient basis with a logistic regression model.

Results

Patients achieved a postoperative mean spherical equivalent of -0.05 diopters (D) in the distant eye and -1.92 D in the near eye. Prior to surgery, 64.7% (n=178) of patients reported they were satisfied or very satisfied with their vision; postoperatively, this increased to 85.4% (n=251). The greatest predictor of dissatisfaction after surgery was severe patient-reported visual phenomena (glare, halos, starbursts, ghosting) (odds ratio 1.18, P=0.001).

Conclusions

LASIK monovision for presbyopic patients with low refractive error and good preoperative uncorrected distance visual acuity is both safe and effective with high patient satisfaction. Patients who were dissatisfied in the postoperative period tended to be those with postoperative visual symptoms.

A systematic review of pseudophakic monovision for presbyopia correction

A systematic review of the recent literature regarding pseudophakic monovision as a reliable methods for presbyopia correction was performed based on the PubMed, MEDLINE, Nature and the American Academy of Ophthalmology databases in July 2015 and data from 18 descriptive and 12 comparative studies were included in this narrative review. Pseudophakic monosvision seems to be an effective method for presbyopia with high rates of spectacles independence and minimal dysphotopsia side-effects, that should be considered by the modern cataract surgeons.

Changes in Keratometric Values and Corneal High Order Aberrations After Hydrogel Inlay Implantation

PURPOSE

We sought to analyze surgically induced refractive change (SIRC) and change in high-order aberration after Raindrop corneal inlay insertion (ReVision Optics, Lake Forest, CA), and assess the extent to which Raindrop corneal inlay insertion could correct presbyopia.

DESIGN

Interventional case series.

METHODS

Seventeen patients were included if they had a corneal thickness ≥500 μm and a stable manifest spherical equivalent refraction between 0.50 and +1.00 diopters (D). The Raindrop corneal inlay was implanted on the stromal bed of a femtosecond laser-assisted generated flap of nondominant eyes. Manifest refraction, corneal powers, and corneal high-order aberrations were measured preoperatively and at 3 and 12 months postoperatively.

RESULTS

The SIRC by manifest refraction was 0.99 ± 0.26 D. The changes derived from simulated keratometry (K), true net power, and equivalent K reading (EKR) at 1.0-4.0 mm were greater than the SIRC (all P < .01) while the change in EKR at 6.0 mm was less than the SIRC (P < .01). The changes in EKR 5.0 mm, automated K, and EKR 4.5 mm did not differ significantly from the SIRC (P = .81, .29, and .09, respectively), and the difference was the least for EKR 5.0 mm. In analysis of high-order aberrations, only spherical aberration showed statistically significant difference between preoperative and postoperative on both anterior cornea and total cornea (all P < .01).

CONCLUSION

Raindrop corneal inlay corrects presbyopia via increasing negative spherical aberration. The equivalent K reading at 5.0 mm accurately reflected the SIRC, and would be applicable for intraocular power prediction before cataract surgery.

Short-term outcomes of combined implantation of diffractive multifocal intraocular lenses with different addition power

PURPOSE

To compare short-term binocular visual function between patients implanted with diffractive multifocal intraocular lenses (MIOLs) of different near addition powers in each eye or the same MIOLs bilaterally.

METHODS

Seventy patients scheduled for implantation of diffractive MIOLs were divided into two groups: (i) mix and match group, a MIOL with +3.0 dioptre (D) addition power implanted in the dominant eye (Alcon SN60D1) and a MIOL with +4.0D power implanted in the non-dominant eye (SN60D3) or (ii) same MIOL group, same MIOL (SN60D1) implanted bilaterally. At 3 months postoperatively, we examined binocular visual acuity (VA) at various distances, binocular contrast VA and that with a glare (glare VA), and near stereoacuity.

RESULTS

Mean binocular uncorrected (UNVA) or corrected near VA (CNVA) at 0.3 m was significantly better in the mix and match group than in the same MIOL group (p ≤ 0.0066). Binocular uncorrected and distance-corrected VA at other distances was similar. Binocular UNVA of 0.8 or better was achieved in 77.1% of patients in the mix and match group and 45.7% in the same MIOL group (p = 0.0144). Binocular contrast and glare VA, and stereoacuity did not significantly differ between groups. Spectacle independence and patient satisfaction with near vision were significantly better in the mix and match group (p ≤ 0.0195).

CONCLUSION

Mix and match implantation of diffractive MIOLs with different addition power provides a better binocular VA curve and spectacle independence than bilateral implantation of the same MIOLs, without compromising contrast sensitivity and stereopsis.

Binocular visual function of modified pseudophakic monovision

PURPOSE

To compare binocular visual function of pseudophakic patients having modified monovision (0.75 diopter [D] anisometropia) with that of patients having conventional monovision (1.75 D anisometropia).

DESIGN

Prospective observational study.

METHODS

Eighty-two patients that underwent bilateral implantation of a monofocal intraocular lens were recruited at 3 months postoperatively. Modified monovision was simulated by adding a +0.75 D spherical lens to the nondominant eye, while conventional monovision was simulated by adding a +1.75 D spherical lens. Binocular corrected visual acuity (VA) at various distances, binocular contrast VA (contrast VA) and that with glare (glare VA), and stereoacuity were evaluated.

RESULTS

With modified monovision, mean binocular corrected intermediate VA at 1.0 m was 20/19 and near VA at 0.3 m was 20/51, and stereoacuity was 125 ± 100 seconds of arc. Mean binocular intermediate VA at 1.0 m was significantly better with modified monovision than with conventional monovision (P = .0001), while near VA and intermediate VA at 0.5 m were significantly worse (P < .0001). Mean binocular photopic and mesopic contrast VA and glare VA tended to be better with modified monovision than with conventional monovision, but the difference was not significant. Mean stereoacuity was significantly better with modified monovision than with conventional monovision (P = .0020).

CONCLUSIONS

Modified pseudophakic monovision provided excellent binocular VA from far to intermediate distances, although near VA was worse than that with conventional monovision. Contrast VA with and without glare tended to be better and stereoacuity was significantly better with modified monovision, suggesting that this method is useful for correcting presbyopia without marked impairment of binocular function.

Extended depth of focus with induced spherical aberration in light-adjustable intraocular lenses

PURPOSE

To evaluate the quality of vision and depth of focus induced by controlled amounts of negative spherical aberration in patients implanted bilaterally with light-adjustable intraocular lenses.

DESIGN

Prospective, nonrandomized clinical trial.

METHODS

Seventeen patients were implanted and treated with appropriate spatial irradiance light profiles. One eye was set for emmetropia, and the fellow eye received an additional aspheric light treatment to induce controlled amounts of negative spherical aberration. We used a Hartmann-Shack sensor to measure the eye's refraction and aberrations for a 4-mm pupil diameter. Decimal visual acuity (VA) was measured using a micro-display placed at 10 m, 60 cm, 40 cm, and 30 cm.

RESULTS

Eyes treated with aspheric profiles were divided into 2 groups depending on the final amount of induced negative spherical aberration: low [-0.05, -0.10 μm] and high [-0.13, -0.23 μm]. In both groups, the mean uncorrected decimal VA at 60 cm was over 0.90. In the first group, distance VA was 0.97 ± 0.16, but in the second group it was lower (0.76 ± 0.16). As expected, the VA for nearer distances is higher in the eyes with a larger magnitude of spherical aberration (P value < .01): 0.94 ± 0.10 and 0.73 ± 0.16 at 40 and 30 cm, respectively, in comparison with 0.71 ± 0.15 and 0.50 ± 0.14. Binocular summation with the fellow eye, adjusted for emmetropia, produces an excellent binocular distance VA (>1.10) in both groups.

CONCLUSIONS

Controlled amounts of negative spherical aberration and defocus can be induced in eyes implanted with adjustable intraocular lenses to enhance near vision.

Intentional extreme anisometropic pseudophakic monovision: new approach to the cataract patient with longstanding diplopia

PURPOSE

To determine whether extreme pseudophakic monovision can reduce or eliminate diplopia in patients with cataract and longstanding acquired strabismus.

SETTING

Department of Ophthalmology, University of Cincinnati, and the Cincinnati Eye Institute, Cincinnati, Ohio, USA.

DESIGN

Case series.

METHODS

Intentional extreme monovision was created in patients with stable diplopia having cataract surgery. Intraocular lens selection was targeted for emmetropia in 1 eye and at least 3.0 diopters of myopia in the fellow eye.

RESULTS

Twelve patients with stable diplopia attained excellent uncorrected distance and near vision with a marked reduction in or elimination of double vision.

CONCLUSION

Patients with stable acquired strabismus with diplopia may be candidates for extreme pseudophakic monovision, which may be a new strategy to eliminate double vision.

FINANCIAL DISCLOSURE

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

Pseudophakic monovision is an important surgical approach to being spectacle-free

There are few studies on pseudophakic monovision even though it is widely applied. We reviewed the published literature on pseudophakic monovision. Surgeons select patients who not only have a strong desire to be free of glasses after surgery, but also fully understand monovision design and its drawbacks. However, other criteria adopted for pseudophakic monovision are very different. Both traditional monovision and cross monovision are used in pseudophakic monovision, and the target binocular anisometropia ranges from -1.0 D to -2.75 D. Postoperative results were acceptable in every study and most patients were satisfied, with vision being improved and presbyopia corrected. Complications were decreased stereopsis, contrast sensitivity, and visual fields, similar to other types of monovision. The term "pseudophakic monovision" should include more than just monocular intraocular lens implantation in two eyes, and further studies are required.