Continuous Corneal Intrastromal Ring Implantation for Treatment of Keratoconus in an Iranian Population

doi:10.1016/j.ajo.2012.11.015

American Journal of Ophthalmology

Volume 155, Issue 5, May 2013, Pages 837-842.e2

https://doi.org/10.1016/j.ajo.2012.11.015 Get rights and content

Purpose

To evaluate the effect of mechanical implantation of a continuous intrastromal ring in keratoconus.

Design

Prospective, interventional, nonrandomized, case series.

Methods

The MyoRing (Dioptex GmbH) was implanted after creation of an intrastromal pocket for 95 eyes of 95 patients with moderate and advanced keratoconus. All patients had at least 12 months of follow-up. Preoperative and postoperative visual acuity, keratometry, aberrometry, and refraction were the main outcome measures of the study.

Results

A significant improvement in uncorrected and corrected distance visual acuity was observed 1 month after surgery, which was consistent with the significant reduction in sphere (5.74 diopters [D]) and cylinder (3.02 D). No significant changes were detected in these parameters afterward. Furthermore, a significant corneal flattening of a mean value of 9.78 D was found. Both spherical myopia and astigmatism underwent reduction, but the reduction in myopia was more remarkable than astigmatism. Higher-order aberrations and coma-like aberrations decreased significantly, but spherical aberrations increased after surgery. No significant change in central corneal thickness was observed at any point after operation. There were no significant differences between 2 keratometry groups (higher or lower than 53 D) in visual gain after the procedure. There were no major complications during or after surgery. MyoRing explantation was performed in 4 eyes (4%). The refraction, visual acuity, and corneal topography returned to the preoperative status 1 month later for all 4 eyes.

Conclusions

MyoRing implantation has an acceptable efficacy profile in moderate and advanced keratoconus.

Section snippets

Methods

The present study was an interventional case series. All procedures were performed by 2 surgeons (M.J. and A.S.) in 2010, with identical surgical techniques. All patients gave informed consent to participate in research and to undergo the proposed treatment, after explanation of other options of treatment. The tenets of the Helsinki Declaration were followed, and the Institutional Review Board of Tehran University approved both the procedures and use of the MyoRing for keratoconic patients

Results

The mean preoperative sphere was −4.6 ± 4.36 D (range, −16.00 to 2.00 D), mean cylinder was −5.3 ± 2.17 D (range, −2.00 to −11.00 D), and mean spherical equivalent was −7.28 ± 4.69 D. Also, the mean keratometry reading was 51.77 ± 3.65 D (range, 48 to 59 D).

Preoperative and postoperative measurements are shown in Table 2. Before surgery, 58% eyes had a UDVA of 20/200 or worse, whereas after 12 months, 42% eyes had a UDVA of 20/40 or better. No significant change in central corneal thickness was

Discussion

The concept of continuous ring implantation into an intrastromal pocket was proposed first in 2008.¹⁰ Its safety and efficacy for myopia correction and keratoconus have been shown and proved in many prior studies.6, 10, 11 In the present study, we demonstrated a reduction in corneal power and astigmatism after MyoRing placement. The reduction in the mean corneal keratometry (9.78 D) and spherical power (5.74 D) was more significant than the cylindrical power reduction (3.02 D; Figure 1).

Mahmoud Jabbarvand, MD, is Professor and Chairman of the Department of Ophthalmology, Tehran University of Medical Sciences (TUMS), Iran. He received his cornea fellowship from TUMS in 1997 and joined the faculty at the Department of Ophthalmology of TUMS. His main areas of research interests are corneal diseases, esp. refractive surgery and keratoconus. Dr Jabbarvand has published extensively in his research fields, with over 50 publications in peer reviewed journals.

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Cited by (41)

Femtosecond laser implantation of a 340-degree intrastromal corneal ring segment in keratoconus: Short-term outcomes
2017, Journal of Cataract and Refractive Surgery
To evaluate the short-term outcomes of femtosecond laser–assisted implantation of a 340-degree intracorneal ring (ICR) (Keraring) in patients with keratoconus.
Four centers in Iran.
Prospective case series.
All cases had implantation of the 340-degree ICR after tunnel creation with a femtosecond laser. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities, sphere, cylinder, manifest refraction spherical equivalent (MRSE), mean keratometry (K), steep K, and flat K were evaluated preoperatively and 1, 3, and 6 months postoperatively.
Eighteen eyes of 17 patients were included. The mean follow-up was 4.33 months (range 1 to 6 months). The mean UDVA improved from 0.95 logarithm of the minimum angle of resolution (logMAR) ± 0.33 (SD) to 0.53 ± 0.35 logMAR (P = .001) and the mean CDVA from 0.39 ± 0.22 logMAR to 0.26 ± 0.21 logMAR (P = .09). The mean sphere decreased from −5.08 ± 3.74 diopters (D) to −1.67 ± 2.59 D, the mean cylinder from −5.83 ± 2.02 D to −2.72 ± 1.81 D, and the mean MRSE from −8.03 ± 3.88 D to −3.01 ± 2.82 D (P < .001). The mean K decreased from 51.43 ± 3.59 D to 47.42 ± 3.59 D (P < .001). All patients with a preoperative mean K greater than 55.0 D had worse CDVA.
Implantation of a 340-degree ICR using femtosecond laser improved the visual, refractive, and topographic parameters in keratoconic patients. The findings indicate that patients with severe keratoconus (mean K >55.0 D) are not good candidates for this type of ICR.
Confocal biomicroscopic changes of the corneal layers following femtosecond laser-assisted MyoRing implantation in keratoconus
2017, Journal of Current Ophthalmology
Citation Excerpt :
Our study demonstrated additional information, including improved uncorrected visual acuity and spherical equivalent 6 months after the operation, about effectivity of the procedure. The improvement in the uncorrected visual acuity and spherical equivalent after the procedure was similar to other studies.5–9 Thus, the femtolaser-assisted MyoRing implantation might be an effective procedure to treat patients with keratoconus.
To evaluate the effect of the femtosecond laser-assisted MyoRing implantation on the confocal biomicroscopic findings in different corneal layers of the patients with keratoconus.
Twelve eyes of 12 patients with mild to moderate keratoconus (keratometry between 48 and 52 diopters) and intolerance to hard contact lens entered the study. All the included patients underwent femtosecond laser-assisted MyoRing (Dioptex GmBH, Linz, Austria) implantation. The confocal biomicroscopy of the cornea was performed for all corneal layers in the center and periphery preoperatively and 3 and 6 months postoperatively. The cell counts and the qualitative findings in each layer of the cornea were compared between preoperative and 3 and 6 months postoperative images.
Compared with preoperative values, the central epithelial and the central and peripheral midstromal cell counts were significantly decreased 6 months after MyoRing implantation (P = 0.015, P = 0.010 and 0.005, respectively). Furthermore, compared with preoperative values, the peripheral posterior stromal cell count was significantly decreased 3 months after MyoRing implantation (P = 0.033). In the qualitative analysis, highly reflective nuclei in the basal epithelium, transient disruption in the subepithelial nerve plexus, increase in the reflectivity of the stromal keratocyte, and normal endothelial cell morphology were seen.
Our study demonstrated some findings similar to that reported in intrastromal corneal ring segments (ICRS): decreased central epithelial cell counts, highly reflective nuclei in the basal epithelium, transient disruption in the subepithelial nerve plexus, and normal endothelial cell count and morphology. In addition, a decrease in the central and peripheral midstromal, transient decrease in posterior stromal cell counts, and absence of amorphous depositions were in contrast with the findings reported in ICRS.
MyoRing treatment of myopia
2017, Journal of Optometry
Citation Excerpt :
The presented data therefore describe the visual results which can be achieved by that method if the patients are properly selected according to the criteria described above. In agreement with the experience with the treatment of keratoconus, no intra- or postoperative complications have been observed in the treatment of myopia.8–11 In conclusion, MyoRing treatment is a safe, effective and fully reversible refractive surgery procedure which gives excellent results in a particular group of myopic patients suffering from moderate and high myopia.
Laser Vision Correction is not always possible for the treatment of myopia. The aim of this paper is to present results after MyoRing implantation in myopic eyes who in their majority were not eligible for LVC. Safety, effectivity and patient selection is discussed. The aim of the treatment was to be spectacle independent in everyday-life.
19 myopic eyes of 12 patients ranging from −2.25 to −16.5 dioptres (D) in sphere and from 0 to −4 D in cylinder were analyzed.
After treatment, 84% of the eyes reached uncorrected distance visual acuity (UDVA) of 0.5 or better, 42% reached UDVA of 0.8 or better and 16% reached UDVA of 1.0 or better. Before treatment, no eye reached UDVA of 0.5 or better. Corrected distance visual acuity (CDVA) preoperatively and postoperatively did not differ. The treatment changed the average spherical equivalent from −10.27 D to −0.93 D. Efficacy index was 0.76 and safety index was 1.02.
MyoRing implantation for myopia is safe and effective with highly satisfied patents in a particular subgroup of myopic patients. Patient selection is important.
La corrección de la visión con láser (CVL) no es siempre posible en el tratamiento de la miopía. El objetivo de este artículo es presentar los resultados tras la implantación de MyoRing en ojos miopes que, en su mayoría, no son aptos para la CVL. Se tratan cuestiones tales como la seguridad, la efectividad y la selección de los pacientes. El objetivo del tratamiento fue el de eliminar el uso de gafas en la vida diaria.
Se analizaron 19 ojos miopes de 12 pacientes, con un rango de -2,25 a -16,5 dioptrías (D) de esfera, y de 0 a -4 D de cilindro.
Tras el tratamiento, el 84% de los ojos logró una agudeza visual lejana sin corrección (UDVA) de 0,5 o superior, el 42% logró una UDVA de 0,8 o superior, y el 16% logró una UDVA de 1,0 o superior. Con anterioridad al tratamiento, ningún ojo logró una UDVA de 0,5 o superior. La agudeza visual lejana corregida (CDVA) no difirió con anterioridad y posterioridad a la operación. El tratamiento modificó el equivalente esférico medio de -10,27 D a -0,93 D. El índice de eficacia fue de 0,76 y el índice de seguridad de 1,02.
La implantación de MyoRing en pacientes miopes es segura y efectiva, con elevada satisfacción por parte de un subgrupo específico de pacientes miopes. Es importante la selección de los pacientes.
Long-term results of MyoRing treatment of keratoconus
2017, Journal of Optometry
To study long-term results of MyoRing treatment of keratoconus.
Retrospective study of MyoRing implantation into a corneal pocket for keratoconus.
Corneal thickness at the thinnest point remained unchanged, SIM K's, manifest sphere and cylinder were significantly improved at the first follow-up 9 months postoperatively and remained stable until the last follow-up about 5 years after surgery. Uncorrected and corrected distance visual acuity (UDVA, CDVA) were significantly improved at the first follow-up 9 months postoperatively and were further ameliorated until the last follow-up about 5 years after surgery.
The treatment was safe and effective with continuing improvement of visual acuity during the 5 years after surgery.
Estudiar los resultados a largo plazo del tratamiento del queratocono con MyoRing.
Estudio retrospectivo de la implantación del MyoRing en un bolsillo corneal en los casos de queratocono.
El espesor de la córnea en el punto más fino no reflejó cambios, mejorando los valores de SIM K, esfera y cilindro manifiesto durante el seguimiento a los 9 meses de la intervención y permaneciendo entonces estables hasta el último seguimiento a los 5 años de la misma. La agudeza visual no corregida y corregida (UDVA, CDVA) mejoró considerablemente a los 9 meses de la intervención, y continuaron mejorando significativamente hasta el último seguimiento a los 5 años de la misma.
El tratamiento resultó seguro y efectivo, con mejora continua de la agudeza visual durante los 5 años posteriores a la cirugía.
Efficacy of MyoRing implantation in the treatment of keratoconus
2024, International Eye Science
Clinical Outcomes of Femtosecond Laser-assisted Implantation of 325-Degree Versus 340-Degree Arc Length Intracorneal Ring Segments in Naive Keratoconic Eyes
2023, Journal of Ophthalmic and Vision Research

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Hesam Hashemian, MD, received his medical degree and internship in Tehran University of Medical Sciences (TUMS), Iran, followed by a residency at Farabi Eye Hospital at 2010. He is now an Assistant Professor at the Department of Ophthalmology, TUMS. His main areas of research interests are corneal diseases, cataract and refractive surgery, and keratoconus. Dr Hashemian has published 10 publications in peer reviewed journals, and edited one international book.

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Original articleContinuous Corneal Intrastromal Ring Implantation for Treatment of Keratoconus in an Iranian Population

Purpose

Design

Methods

Results

Conclusions

Section snippets

Methods

Results

Discussion

J Cataract Refract Surg

J Cataract Refract Surg

J Cataract Refract Surg

J Cataract Refract Surg

Ophthalmology

J Cataract Refract Surg

J Cataract Refract Surg

J Cataract Refract Surg

Ophthalmology

Ophthalmology

Original article
Continuous Corneal Intrastromal Ring Implantation for Treatment of Keratoconus in an Iranian Population