Correction of hyperopia by intrastromal cutting and liquid filler injection

Freidank, Sebastian; Vogel, Alfred; Anderson, R. Rox; Birngruber, Reginald; Linz, Norbert

doi:10.1117/1.jbo.24.5.058001

Cited by 7 publications

(7 citation statements)

References 48 publications

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“…Other groups have tried to use a peripheral corneal gel injection to demonstrate myopia correction 13 and a pilot in vitro study in pig eyes demonstrated the feasibility of the central approach for hyperopia. 14 Analogous to the previous studies, which used firm corneal extension materials, a change in both the anterior and posterior surfaces was observed to correct hyperopia. This study reports the first systematic evaluation of refractive changes after filler injection in 120 rabbit eyes and provides a quantitative analysis of the achieved surgical results and demonstrates the adjustability of the approach.…”

mentioning

confidence: 68%

Refractive Changes After Corneal Stromal Filler Injection for the Correction of Hyperopia

Wertheimer¹,

Brandt²,

Kaminsky³

et al. 2020

J Refract Surg

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Hyperopia affects approximately 25% of the general population. 1 Currently available surgical options for the correction of hyperopia have significant disadvantages. Laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) can only be used for low hyperopia and are accompanied by an increased risk of regression, repeated corrective surgery, and higher order aberrations, 2 mainly due to ABSTRACT PURPOSE: To evaluate a new non-ablative and adjustable procedure for laser ablative refractive corneal surgery in hyperopia using the injection of a biocompatible liquid filler material into a stromal pocket. METHODS:A total of 120 stromal pockets were created using a clinical femtosecond laser system in 96 rabbit corneoscleral discs and 24 whole globes. Pockets were cut at a depth of 120 or 250 µm below the epithelial surface. Hyaluronic acid was injected manually into the pocket. To determine the refractive changes, three-dimensional optical coherence tomography images and a specifically developed picture recognition Matlab (The Mathworks) routine were used. RESULTS:After injection, a steepening of the anterior and flattening of the posterior corneal surface was observed, which led to hyperopic correction. The two main factors determining the amount of correction were the pocket depth and the injected volume. After the pocket was homogeneously filled, an initial refractive increase was observed, followed by a linear relation between the injected volume and the refraction increase. CONCLUSIONS:This possible clinical protocol for controlled refraction correction of hyperopia suggests a potential readjustable clinical application.

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mentioning

confidence: 68%

Refractive Changes After Corneal Stromal Filler Injection for the Correction of Hyperopia

Wertheimer¹,

Brandt²,

Kaminsky³

et al. 2020

J Refract Surg

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“…The increased precision and reduction in mechanical side effects in intrastromal cutting by the use of a vortex beam make this a promising approach for flap cutting in LASIK 4 and intrastromal pocket dissection for hyperopia correction 13,14 and offers even greater potential for improving SMILE. 10 In SMILE, a small lenticule is dissected and removed through a small side cut to achieve refractive correction in one step.…”

Section: Potential Improvements Of Refractive Surgery By Focus Shapingmentioning

confidence: 99%

“…Recently, a novel approach for hyperopia correction based on dissection of an intrastromal pocket followed by the injection of a biocompatible filler material has been introduced. 13,14 Despite more than 20 years of experience with LASIK and SMILE, there is still room for improvement with regard to efficiency, precision, and safety. Significant improvements can be achieved by addressing the key step of the refractive laser procedure: intrastromal dissection.…”

Section: Introductionmentioning

confidence: 99%

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Optical Vortex Beam for Gentle and Ultraprecise Intrastromal Corneal Dissection in Refractive Surgery

Freidank

Vogel

Linz

2020

Trans. Vis. Sci. Tech.

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We introduce a novel focus shaping concept for intrastromal corneal dissection that facilitates cleavage along corneal lamellae, and we analyze laser-tissue interactions governing cutting effectiveness and mechanical side effects. Methods: Focus shaping was achieved by a spiral phase plate that converts an incident Gaussian beam into a Laguerre-Gaussian beam with a helical phase. Such vortex beams have zero intensity at their center, are propagation invariant, and possess a ring focus equal in length to the Gaussian focus but with a larger diameter. Cutting precision and the required absorbed energy for flap dissection were compared for Gaussian and vortex beams on ex vivo porcine corneal specimens at pulse durations between 480 fs and 9 ps. Cutting quality and bubble formation were characterized by scanning electron microscopy and macro photography. Results: With the vortex beam, the cuts were much smoother. Bubble formation was markedly reduced because cutting can be performed close to the bubble threshold, whereas with the Gaussian beam energies well above threshold are needed. Although the incident energy at the flap dissection threshold was slightly larger for the vortex beam, the absorbed energy was much smaller and contributed more effectively to cutting. This reduced plasma-induced pressure more than sevenfold. Conclusions: The vortex beam approach for corneal dissection is a simple, versatile, and cost-effective way of improving the precision of refractive surgery while reducing bubble formation and pressure-related mechanical side effects. Translational Relevance: Phase plates for propagation invariant vortex beams are easily implemented in the beam path of next-generation clinical devices.

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“…A previous ex vivo study showed that corneal filler injection is feasible for correcting hyperopia. 17 The following ex vivo pilot study explores the principle of corneal filler injection to establish corneal bifocality to correct presbyopia in an individual and adjustable manner.…”

Section: Introductionmentioning

confidence: 99%

Corneal Stromal Filler Injection as a Novel Approach to Correct Presbyopia—An Ex Vivo Pilot Study

Kassumeh

Luther

Wertheimer

et al. 2020

Trans. Vis. Sci. Tech.

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To evaluate the ex vivo feasibility of corneal stromal filler injection to create bifocality to correct presbyopia by flattening the central posterior corneal surface and thus increase refractive power. Methods: Femtosecond laser-assisted corneal stromal pockets of varying diameters close to the posterior corneal curvature were cut into rabbit eyes ex vivo. Subsequently, hyaluronic acid was injected to flatten the central posterior curvature. Refractive parameters were determined using perioperatively acquired three-dimensional optical coherence tomography (OCT) scans. Using micrometer-resolution OCT, corneal endothelial cell morphology and density were evaluated. Results: Following filler injection into the corneal stromal pockets, a fair volumedependent increase of central refractive power up to 4 diopters (dpt) was observed. Unremarkable refractive changes of the peripheral posterior (3 mm, 0.20 ± 0.11 dpt; 2 mm, 0.11 ± 0.10 dpt) and the anterior corneal curvature (3 mm, 0.20 ± 0.34 dpt; 2 mm, 0.33 ± 0.31 dpt) occurred. Only negligible changes in astigmatism were observed. Different sizes of optical zones could be established. Furthermore, no alterations of corneal endothelial morphology or endothelial cell density (2831 ± 356 cells/mm 2 vs. 2734 ± 292 cells/mm 2 ; P = 0.552) due to the adjacent laser treatment were observed. Conclusions: The ex vivo investigations proved the principle of injecting a filler material into femtosecond laser-created corneal stromal pockets close to the posterior corneal curvature as an efficacious, individually adjustable, and novel approach to correct presbyopia without ablating corneal tissue. Translational Relevance: Due to the aging population worldwide, presbyopia is an increasing problem; thus, our study may encourage further exploration to extend the treatment spectrum of clinically used femtosecond laser systems to correct presbyopia.

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Correction of hyperopia by intrastromal cutting and liquid filler injection

Cited by 7 publications

References 48 publications

Refractive Changes After Corneal Stromal Filler Injection for the Correction of Hyperopia

Refractive Changes After Corneal Stromal Filler Injection for the Correction of Hyperopia

Optical Vortex Beam for Gentle and Ultraprecise Intrastromal Corneal Dissection in Refractive Surgery

Corneal Stromal Filler Injection as a Novel Approach to Correct Presbyopia—An Ex Vivo Pilot Study

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