Permalens Hydrogel Intracorneal Lenses for Spherical Ametropia

Permavision intracorneal inlay after sixteen years. Regression of initial refractive hyperopia

According to the available scientific literature, 77 patients underwent Permavision inlay worldwide, between 2004 and 2007. This study reported about the use of Permavision intracorneal inlay to increase the central corneal curvature and to correct hyperopia. A 32-year-old male patient went to the Tecnolaser Clinic Vision ® facilities for a refractive study. Preoperative refraction without cycloplegia was +6.00 D in the right eye (RE) and +4.00 in the left eye (LE). The surgery was performed for both eyes on December 2, 2003. The Carriazo-Barraquer mechanical microkeratome (Moria) was used to create a 180 μm-thick corneal flap with a diameter of 8.5 mm. After lifting the flap, the corneal inlay was placed centrally above the pupil and the flap was re-positioned. In this case report, the patient reverted to the initial refractive situation. The first refractive regression appeared at twelve-month follow-up. After sixteen years, it was found a decrease in maximum corneal curvature, an increase in mean corneal densitometry percentage, and no important changes in the central corneal thickness. In the reported case, the cornea reverted to its original shape. In the scientific literature, this is the first case report of a non-explanted Permavision inlay after sixteen years.

Correction of hyperopia by intrastromal cutting and liquid filler injection

Correction of hyperopia requires an increase of the refractive power by steepening of the corneal surface. Present refractive surgical techniques based on corneal ablation (LASIK) or intrastromal lenticule extraction (SMILE) are problematic due to epithelial regrowth. Recently, it was shown that correction of low hyperopia can be achieved by implanting intracorneal inlays or allogeneic lenticules. We demonstrate a steepening of the anterior corneal surface after injection of a transparent, liquid filler material into a laser-dissected intrastromal pocket. We performed the study on ex-vivo porcine eyes. The increase of the refractive power was evaluated by optical coherence tomography (OCT). For a circular pocket, injection of 1 μl filler material increased the refractive power by +4.5 diopters. An astigmatism correction is possible when ellipsoidal intrastromal pockets are created. Injection of 2 μl filler material into an ellipsoidal pocket increased the refractive power by +10.9  dpt on the short and +5.1  dpt on the long axis. OCT will enable to monitor the refractive change during filler injection and is thus a promising technique for real-time dosimetry.

Flap Melting Over Corneal Inlay for Hyperopic Correction

PURPOSE

To report two cases of flap melting over corneal inlays for hyperopic correction several years after implantation.

METHODS

The corneal inlay (+6.00 diopters [D]; PermaVision intracorneal lens; Anamed Inc., Lake Forest, CA) was implanted underneath a LASIK flap in two patients.

RESULTS

Visual acuity and slit-lamp findings of both patients were stable for several years. At 9 years postoperatively, the first patient presented with a sudden loss of corrected distance visual acuity (CDVA) due to partial flap melting over the inlay while the surrounding anterior cornea showed opacification. The inlay was explanted immediately. Three years after explantation, CDVA returned to 1.0. Similarly, the second patient presented 11 years postoperatively with loss of vision, opacification, and partial flap melting. The inlay was explanted. Two years later, CDVA recovered.

CONCLUSIONS

Potentially severe biocompatibility issues of corneal inlays may occur even after several uneventful years. [J Refract Surg. 2018;34(11):775-778.].

Intracorneal Inlays for the Correction of Ametropias

Various materials have been placed in the corneal stroma to modify a spherical refractive error (usually hyperopic). As the surgical procedures evolved to simplify the insertion process so has the quality and biocompatibility of the implanted materials. Failures have been due to excessive inlay dimensions, bioincompatibility of the materials used, poor choice of test model, or combinations of the above. We present a thorough analysis of the history of the intracorneal inlay and the materials and techniques used up to and including the current materials and techniques available for the correction of spherical refractive errors.

One-year visual outcomes and patient satisfaction after surgical correction of presbyopia with an intracorneal inlay of a new design

PURPOSE

To evaluate the safety and efficacy of the third-generation Kamra corneal inlay (ACI 7000PDT) implanted monocularly in corneal pockets of emmetropic presbyopic patients to improve near and intermediate vision.

SETTING

University Eye Clinic, Paracelsus Medical University, Salzburg, Austria.

DESIGN

Cohort study.

METHODS

The corneal inlay was implanted in the nondominant eye over the line of sight by creating a corneal pocket with a femtosecond laser. The minimum postoperative follow-up was 12 months. Distance, intermediate, and near visual acuities were assessed over the follow-up. Other examinations included slitlamp evaluation, central keratometry, computerized corneal topography, endothelial cell count, and central corneal thickness. Patients completed satisfaction questionnaires preoperatively and 3, 6, and 12 months postoperatively.

RESULTS

The study evaluated 24 patients. After a mean follow-up of 12 months, 92% of patients read Jaeger (J) 3 or better with the surgical eye, the mean binocular uncorrected near visual acuity improved from J5 preoperatively to J2, and the mean binocular uncorrected intermediate visual acuity was 20/20 (67% ≥ 20/20). At 12 months, the mean uncorrected distance visual acuity was 20/20 in the surgical eye and 20/16 binocularly. Patients reported no change in distance vision, and their need for reading glasses decreased significantly (P<.001). No inlay was explanted and or recentered during the reported follow-up.

CONCLUSION

The new corneal inlay was a safe and effective treatment for presbyopia over a 1-year follow-up.

Refractive surgical correction of presbyopia with the AcuFocus small aperture corneal inlay: two-year follow-up

PURPOSE

To evaluate the safety and efficacy of the AcuFocus Corneal Inlay 7000 (ACI 7000) implanted in emmetropic presbyopic patients for the improvement of near and intermediate vision over 2-year follow-up.

METHODS

This prospective, non-randomized, non-comparative study included 32 naturally emmetropic presbyopic patients. The intracorneal inlay was implanted in the non-dominant eye over the pupil by creating a superior-hinged flap with the IntraLase 60-kHz femtosecond laser (Abbott Medical Optics). Inlay centration was over the line of sight. Minimum postoperative follow-up was 24 months.

RESULTS

After mean follow-up of 24.2±0.8 months (range: 24 to 26 months), 96.9% of patients read J3 or better in the implanted eye. Mean binocular uncorrected near visual acuity improved from J6 preoperatively to J1 after 24 months. Mean binocular uncorrected intermediate visual acuity (UIVA) was 20/20 at 1 month and remained 20/20 throughout 24-month follow-up, with 71.9% of eyes reaching UIVA of 20/20 or better. At 24 months, mean uncorrected distance visual acuity was 20/20 in the implanted eye and 20/16 binocularly. No inlay was explanted during the study. Two decentered inlays were recentered after 6 months because of in-sufficient increase in near and intermediate visual acuity. Both patients' near and intermediate visual acuity improved significantly after recentration.

CONCLUSIONS

The ACI 7000 seems to provide a safe and effective treatment for presbyopia over follow-up of 2 years.

Hydrogel intracorneal inlays for the correction of hyperopia: outcomes and complications after 5 years of follow-up

PURPOSE

To evaluate safety and efficacy of an intracorneal inlay for the correction of hyperopia.

DESIGN

A prospective, nonrandomized, noncomparative, 2-center study.

PARTICIPANTS

Thirty-four hyperopic eyes were implanted with a hydrogel intracorneal inlay (Permavision, Anamed, Lake Forest, CA). Preoperative hyperopia was +3.9 diopter (D; range, +2 to +7). Uncorrected visual acuity (UCVA) was the logarithm of the minimum angle of resolution (logMAR; the decimal logarithm of decimal visual acuity with a minus sign) 0.6 +/- logMAR 1, and best-corrected visual acuity (BCVA) was logMAR 0.1 +/- 0.7.

METHODS

Corneal flaps were created with a mechanical microkeratome (M2 [Moria, Anthony, France] or Amadeus [Advanced Medical Optics Inc, Santa Ana, CA]; 180 microm), followed by inlay implantation onto the stromal bed over the pupillary center and covered by the corneal flap. Follow-up was 5 years.

MAIN OUTCOME MEASURES

We measured UCVA and BCVA; patients underwent, slit-lamp examination, pachymetry, and confocal microscopy. The follow-up was up to 6 years.

RESULTS

The UCVA improved during 3 months and was stable for up to 2 years. There was a loss of > or =2 lines of spectacle-corrected visual acuity in 35% of eyes at 2 years, and a loss of > or =2 lines in 55.5% of the eyes at 5 years. Refractive predictability was poor, with 60% of the eyes having +/-3.00 D of emmetropia. A decentration of the inlay occurred in 29.4%, progressive perilenticular deposits were observed in 88.2%, haze was seen in 73.5%, and the inlay was explanted in 58.8%, with a cumulative survival rate of 58.4%.

CONCLUSIONS

An intracorneal inlay may be an option to treat hyperopia, but the tested inlay caused significant visual loss and scarring and had to be explanted in the majority of cases.

Hyperopic LASIK Following Intracorneal Hydrogel Lens Explantation

PURPOSE

To report hyperopic LASIK results after intracorneal hydrogel lens explantation in a bilateral hyperopic patient.

METHODS

Slit-lamp examination showed diffuse corneal opacity around the lens edge and over the anterior lens surface affecting both eyes with uncorrected visual acuity of 0.4 in the right eye and 0.5 in the left eye.

RESULTS

The intracorneal hydrogel lenses were explanted, and 6 months later hyperopic LASIK using the Schwind ESIRIS excimer laser (Schwind, Kleinostheim, Germany) was performed after lifting the same flap for the intracorneal hydrogel lens implantation. Six months after hyperopic LASIK, visual acuity recovered to the initial preoperative best spectacle-corrected levels: right eye 0.8 with +1.50 D sphere and left eye 0.9 with +1.00 -0.50 x 90 degrees. Central corneal transparency also fully recovered.

CONCLUSIONS

Hyperopic LASIK is a possible alternative after intracorneal hydrogel lens explantation in hyperopic eyes.

Intracorneal Hydrogel Lenses and Corneal Aberrations

PURPOSE

To investigate the optical performance of the cornea based on corneal aberrometry following intracorneal hydrogel lens implantation.

METHODS

A retrospective, nonconsecutive, observational study of the anterior corneal surface aberration profile of four hyperopic eyes previously implanted with an intracorneal hydrogel lens were studied by videokeratographic elevation maps before and 6 months after surgery.

RESULTS

Intracorneal hydrogel lenses reduced the optical performance in all four eyes by increasing the spherical aberrations by a mean factor of 1.87 and 1.95, coma aberrations by a mean factor of 2.98 and 3.01, and total higher order aberrations by a mean factor of 2.6 and 2.17 at 3.0-mm and 6.5-mm pupils, respectively (P<.005).

CONCLUSIONS

Intracorneal hydrogel lenses decreased the optical performance of the cornea by significantly increasing spherical, coma, and total higher order aberrations.

Photoablative inlay laser in situ keratomileusis (PAI-LASIK) in the rabbit model

PURPOSE

To evaluate the suitability, biocompatibility, and efficacy of a proprietary hydrogel photoablative inlay (PAI) for use during laser in situ keratomileusis (LASIK).

SETTING

Laboratory study, Tulane University Health Sciences Center, New Orleans, Louisiana, USA.

METHODS

Eight rabbits (1 eye each) underwent the PAI-LASIK procedure; 4 eyes had a disk-shaped inlay and 4, a donut-shaped inlay. Preoperatively, the hydrogel material was ablated with a programmed correction of 5.0 diopters of hyperopia or myopia.

RESULTS

The eyes were followed for 1 to 16 months. No eye showed signs of rejection or extrusion of the PAI. There was no significant difference in corneal clarity or the healing rate between eyes with donut-shaped PAIs and those with disk-shaped PAIs. One eye with a donut-shaped PAI had minimal corneal haze. The remaining inlays did not opacify or fracture during ablation.

CONCLUSION

The hydrogel material can be used for the proposed PAI-LASIK procedure.

PermaVision intracorneal lens for the correction of hyperopia

PURPOSE

To evaluate the safety, predictability, and efficacy of sutureless synthetic keratophakia (SSK) with PermaVision intracorneal lens (Anamed) implantation.

SETTING

Ophthalmic Hospital, Rome, Italy.

METHODS

This retrospective study analyzed the refractive outcomes in 10 eyes of 6 patients who had SSK with PermaVision lens implantation for spherical hyperopia (cylinder less than 1.0 diopter [D]). Preoperatively, the mean spherical equivalent (SE) refraction was +4.33 D +/- 1.52 (SD) (range +3.00 to +6.37 D). All procedures were performed using the Hansatome microkeratome (Bausch & Lomb) with a superior hinge except in 1 eye in which the flap was cut using the Amadeus microkeratome (Allergan) with a nasal hinge.

RESULTS

Six months after PermaVision lens insertion, the mean SE refraction was +0.03 +/- 0.36 D (range -0.50 to +0.38 D), the mean uncorrected visual acuity was 0.85 +/- 0.13 (range 0.63 to 1.00), and the mean best corrected visual acuity was 0.99 +/- 0.19 (range 0.63 to 1.25). No eye lost lines of visual acuity. In 1 eye, the lens was acutely decentered and had to be explanted.

CONCLUSIONS

Sutureless synthetic keratophakia with the PermaVision intracorneal lens is a new technique for the correction of hyperopia. It is easy to perform as well as reversible, and the learning curve of the experienced laser in situ keratomileusis surgeon is short. The technique was safe and effective for spherical hyperopia, but longer follow-up and additional cases are needed to draw conclusions about the efficacy of the technique.

Confocal Microscopy of Corneas With an Intracorneal Lens for Hyperopia

PURPOSE

We evaluated short-term results and confocal microscopic corneal changes following intracorneal lens implantation.

METHODS

In six eyes of three patients with hyperopia between +3.00 and +6.00 diopters (D), an intrastromal hydrogel lens (Permavision, Anamed, Anaheim, Calif) was implanted. Mean baseline hyperopia was +3.90 D. Manifest refraction, uncorrected visual acuity, and spectacle-corrected visual acuity were evaluated. We also performed confocal real-time microscopy with a water immersion objective. Corneal optical sections were recorded and reviewed frame by frame. Examinations were done at months 3, 6, and 12 after intracorneal lens implantation.

RESULTS

After surgery, the spherical equivalent refraction was within +/- 0.50 D in 83% (five of six eyes) at 3 months and 100% (six eyes) at 6 and 12 months. Uncorrected visual acuity (UCVA) at 3 months was within 20/40 or better in 67% (four eyes) and in 100% (six eyes) at 6 and 12 months; no eyes had 20/20 or better UCVA at 3 and 6 months. One eye (17%) had 20/20 or better UCVA at 12 months. On confocal microscopy, one eye had an amorphous deposit adjacent to the lens and presumed fibroblastic activity in the same stromal area at 6 months, which was non-progressive up to 12 months.

CONCLUSION

Intracorneal lenses may be a treatment option for correction of spherical hyperopia. Predictability must be improved but results in these six eyes were stable up to 1 year. Confocal miscroscopy confirmed biocompatibility and showed no abnormal changes, except two spots of hypercellularity in one eye.