Akkommodation und Presbyopie: Teil 2: Operative Verfahren zur Presbyopiekorrektur

Increasing depth of focus with allogeneic presbyopic inlays: 3-year results

PURPOSE

To demonstrate the safety and efficacy of allogenic corneal inlays designed to increase the depth of focus (DoF) in treated eyes.

SETTINGS

Medipol University Hospital, Istanbul, Turkey.

DESIGN

Prospective case series.

METHODS

This study includes 50 eyes of 25 patients with a follow-up of 3 years. Emmetropic patients with presbyopia had implantation of allogenic corneal inlays in the nondominant eye. The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and uncorrected near visual acuity (UNVA) were evaluated in all eyes. A subjective visual acuity test system (Multifocal Lens Analyzer 3.0 application) was used to analyze the DoF by measuring the defocus curves.

RESULTS

No significant difference between the treated and fellow eyes in UDVA and CDVA was found, whereas UNVA was significantly better in the treated eyes ( P = .20, P = .07, P < .01, respectively). Comparing to the preoperative CDVA, there was a 1-line decrease in CDVA in 6 (%24) patients. The mean defocus curves reveal a DoF of 1.1 diopters (D) for the untreated eye at the logMAR = 0.2 threshold. By contrast, the mean DoF of the treated eye and binocularly was 2.8 D. The areas under the curve were significantly better in the near, intermediate, and total distances in the treated eyes, whereas it was better for the far distances in the untreated eyes. All values were significant ( P = .023 total, P < .01 others).

CONCLUSIONS

Allogenic presbyopic inlay implantation may be safe and provided a clinically and statistically significant increase in the DoF leading to good far, intermediate, and near-visual acuity in emmetropic presbyopic patients.

Evaluation of a Device for Standardized Measurements of Reading Performance in a Prepresbyopic Population

PURPOSE

Automated measurements of reading performance are required for clinical trials involving presbyopia-correcting surgery options. Repeatability of a testing device for reading (Salzburg Reading Desk) was evaluated in a prepresbyopic population.

METHODS

Subjective reading performance of 50 subjects divided into 2 age groups (23-30 years and 38-49 years) with distance-corrected eyes was investigated with different log-scaled reading charts. At study entry, refractive parameters were measured and distance visual acuity assessed. Two standardized binocular measurements were performed for each subject (32.24 ± 9.87 days apart [mean ± SD]). The repeatability of the tests was estimated using correlation coefficients, Wilcoxon signed-rank test, and Bland-Altman method.

RESULTS

The test parameters at both maximum reading rate (MRR) measurements demonstrate a strong relationship of age group 2 subjects (correlation coefficient [r] = 0.74 p = 10^-4) and of younger subjects (age group 1: r = 0.69, p = 10^-4). Prepresbyopic subjects of age group 2 showed moderate results for near reading distance (r = 0.67, p = 10^-4); by contrast, younger subjects had poorer results (r = 0.55, p = 10^-3). The Wilcoxon signed-rank test revealed agreement between measurements and Bland-Altman plots showed a wide data spread for MRR and near reading distance in both groups.

CONCLUSIONS

The device measures repeatedly selected reading performance parameters of near real world conditions, such as MRR, in prepresbyopic populations if several factors are taken into account. The option to choose preferred distance leads to more variance in measuring repeated reading performance.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS) registration reference number: DRKS00000784.

A Review of Presbyopia Treatment with Corneal Inlays

The prevalence of presbyopia continues to increase every year. The therapeutic approaches to presbyopia cover the spectrum of non-surgical to surgical techniques. With recent advances in biocompatible materials, corneal inlays make a strong case for their place within the treatment spectrum. This article takes a closer look at three of the current corneal inlay models: KAMRA, Raindrop, and Presbia Flexivue Microlens. Each design approach and mode of action is described with data from key clinical trials. Furthermore, the ability to choose the most suitable corneal inlay is presented by comparing each model and identifying their similarities and differences. The article then concludes by touching on the future of corneal inlays, looking at associated conditions and complications and how to manage them, as well as an expert’s personal point of view of enhanced ideas for continuing the growth and success of corneal inlays in the market.

Bifocal refractive corneal inlay implantation to improve near vision in emmetropic presbyopic patients

PURPOSE

To evaluate the safety and effectiveness of the Flexivue Microlens corneal inlay for the improvement of near vision in emmetropic presbyopic patients.

SETTING

Ophthalmology Department, Misericordia e Dolce Hospital, Prato, Italy.

DESIGN

Prospective interventional case series.

METHODS

Corneal inlay implantation was performed in nondominant eyes using a 150 kHz femtosecond laser (iFS). Refraction, uncorrected (UNVA) and corrected (CNVA) near visual acuities, uncorrected (UDVA) and corrected (CDVA) distance visual acuities, slitlamp evaluation, wavefront aberrometry, photopic and mesopic contrast sensitivity, anterior segment optical coherence tomography, endothelial cell density, and central corneal thickness measurements were assessed preoperatively and at each postoperative visit.

RESULTS

The study evaluated 81 eyes. In 26 eyes, the mean preoperative UNVA and UDVA were 0.76 logMAR and 0.00 logMAR, respectively, compared with 0.10 logMAR and 0.15 logMAR, respectively, 36 months postoperatively. Sixteen (62%) of 26 treated eyes lost more than 1 line of UDVA, and 5 (19%) lost more than 2 lines of UDVA. Two eyes (8%) lost more than 1 line of CDVA at 36 months. The mean binocular UDVA was 0.00 logMAR preoperatively and 0.02 logMAR at 36 months. The mean spherical aberration increased after surgery. Statistically significant differences in the mean mesopic and photopic contrast sensitivities at higher spatial frequencies were found between treated eyes and nontreated eyes. Explantation was performed in 6 treated eyes because of halos, glare, and a reduced UDVA.

CONCLUSION

The corneal inlay might be a safe and effective method of improving UNVA in emmetropic presbyopic patients.

FINANCIAL DISCLOSURE

Dr. Fantozzi is a member of the Presbia medical advisory board. No other author has a financial or proprietary interest in any material or method mentioned.

Implantable inlay devices for presbyopia: the evidence to date

By 2020, it is estimated that 2.1 billion people will be presbyopic, and the demand for spectacle independence in this group is growing. This review article provides an overview of the three commercially available corneal inlays for the correction of presbyopia. Safety, efficacy, visual outcomes, and complications are analyzed for all three inlays according to published peer-reviewed data.

Corneal hysteresis, corneal resistance factor, and intraocular pressure measurements in eyes implanted with a small aperture corneal inlay

PURPOSE

To compare the postoperative corneal hysteresis (CH) and corneal resistance factor (CRF) of eyes implanted with a small aperture corneal inlay versus fellow eyes.

METHODS

Medical records of patients who underwent small aperture corneal inlay (KAMRA; AcuFocus, Inc., Irvine, CA) implantation were retrospectively reviewed. There were two groups: the implanted and non-implanted. Main outcome measures were CH, CRF, Goldmann-correlated intraocular pressure (IOPg), corneal-compensated IOP (IOPcc), and Goldmann applanation tonometry measurements performed preoperatively and at postoperative week 1 and months 1, 3, and 6.

RESULTS

The study included 68 eyes of 34 patients. CH was higher in the implanted group when compared with the non-implanted group at postoperative week 1 (12.2 ± 3.1 vs 10.9 ± 1.7 mm Hg; P = .007) and month 1 (12.3 ± 2.5 vs 10.9 ± 1.8 mm Hg; P = .001). CRF was higher in the implanted group when compared with the non-implanted group at postoperative week 1 (11.9 ± 2.9 vs 10.7 ± 1.6 mm Hg; P = .003) and month 1 (12.5 ± 2.5 vs 10.4 ± 1.8 mm Hg; P < .001). IOPcc was higher in the implanted group when compared with the non-implanted group at only the first postoperative month (17.1 ± 3.5 vs 14.3 ± 2.9 mm Hg; P < .001). There were no statistically significant differences in Goldmann applanation tonometry or IOPg measurements between the two groups (P > .05). At the 3-month postoperative visit, all parameters had returned to baseline and there was no change at the 6-month visit.

CONCLUSIONS

Implantation of the KAMRA corneal inlay does not induce a permanent change in CH or CRF. A transient increase in both was seen in the early postoperative period.

[Intrastromal femtosecond laser-based presbyopia correction]

The surgical correction of presbyopia is gaining more and more popularity in the field of refractive surgery. Besides intraocular treatment with multifocal or accommodative intraocular lenses more and more corneal laser approaches are being established. These are performed either with the Excimer laser as laser in situ keratomileusis (LASIK) or the femtosecond laser. The femtosecond laser treatment is done purely intrastromally without dissection of the epithelium and is characterized by an extremely low risk of infection and inflammation. The procedure leads to a central corneal steepening with more prolate shape and increase in depth of field. This leads to a better uncorrected near visual acuity, however, corrected distance visual acuity might be reduced due to these changes.

Cataract surgery with implantation of an artificial lens

BACKGROUND

Cataract surgery, the most frequently performed operative procedure worldwide, typically concludes with the implantation of an artificial intraocular lens (IOL) to correct aphakia (absence of the crystalline lens).

METHOD

Selective literature review including current regulations, guidelines and recommendations for cataract surgery.

RESULTS

The main symptom of cataract is loss of visual acuity, which usually progresses slowly. It can arise in one eye or both. There is a basic distinction between congenital and acquired cataracts. The probability of developing a cataract rises with age because of biochemical aging processes. The development of a cataract becomes highly likely from the sixth decade of life onward.

CONCLUSIONS

As no effective medications for cataract are available at present, its current standard treatment is the removal of the clouded lens. In industrialized countries, this is usually done with ultrasound (phacoemulsification), followed by the implantation of an IOL.