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CASE REPORT
Year : 2021  |  Volume : 1  |  Issue : 1  |  Page : 88-90

Femtosecond laser-assisted intrastromal MyoRing implantation for correction of irregular astigmatism after penetrating keratoplasty and high myopia


The Cheboksary Branch of the S. Fyodorov Eye Microsurgery Federal State Institution, Cheboksary, Russia

Date of Submission27-Apr-2020
Date of Acceptance23-Jul-2020
Date of Web Publication31-Dec-2020

Correspondence Address:
Dr. Sinitsyn Maksim Vladimirovich
10, Tractorostroiteley Avenue, 428028, Cheboksary
Russia
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijo.IJO_1053_20

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  Abstract 


MyoRing was implanted using a femtosecond laser to correct a high irregular corneal astigmatism after penetrating keratoplasty and high myopia. Femtosecond laser-assisted intrastromal MyoRing implantation allows to increase its sphericity, regularity and at the same time to correct high myopia. The creation of an additional “framework” in the corneal transplant by the MyoRing increased its biomechanical properties and prevented regression of the obtained refractive result. Femtosecond laser-assisted intrastromal MyoRing implantation allows to correct irregular astigmatism after penetrating keratoplasty and high myopia.

Keywords: Femtosecond laser, high myopia, irregular astigmatism, MyoRing


How to cite this article:
Aleksandrovna PN, Vladimirovich SM. Femtosecond laser-assisted intrastromal MyoRing implantation for correction of irregular astigmatism after penetrating keratoplasty and high myopia. Indian J Ophthalmol Case Rep 2021;1:88-90

How to cite this URL:
Aleksandrovna PN, Vladimirovich SM. Femtosecond laser-assisted intrastromal MyoRing implantation for correction of irregular astigmatism after penetrating keratoplasty and high myopia. Indian J Ophthalmol Case Rep [serial online] 2021 [cited 2021 Feb 26];1:88-90. Available from: https://www.ijoreports.in/text.asp?2021/1/1/88/305472



One of the main problems after penetrating keratoplasty is postoperative astigmatism.[1] The irregular postoperative astigmatism reduces vision, causes difficulties in selecting spectacle and contact correction, and leads to patient dissatisfaction with the postoperative result.[2],[3],[4]

In 2007, A. Daxer proposed MyoRing (Dioptex, Austria) implantation to correct the spherical component of myopia to –20.0 D and the corneal astigmatism to –4.5 D.[5] We decided to use this technology to correct induced irregular astigmatism after penetrating keratoplasty and high myopia at the same time.


  Case Report Top


Patient K., 31 years old, was admitted to the hospital with a diagnosis of the right eye: Induced irregular astigmatism of a high degree, a condition after femtosecond laser-assisted penetrating keratoplasty; left eye: Condition after MyoRing implantation, the third stage of keratoconus (according to the Amsler-Krumich classification); both eyes: High myopia.

Femtosecond laser-assisted penetrating keratoplasty on the right eye was performed in 2017 at the fourth stage of keratoconus (according to the Amsler-Krumich classification). The length of the right eye was 30.8 mm, the length of the left eye was 30.6 mm. Visual acuity of the both eyes was not corrected with spectacles or contact lens.

During biomicroscopy the corneal transplant of the right eye was clear, 8.0 mm in diameter. The cornea of the left eye was clear, cone-shaped with a thinning in the center, the MyoRing was centered.

Before and after the operation we examined the anterior eye segment of the right eye with an optical coherence tomography OCT Visante (Zeiss, Germany), a corneal topographer TMS-4 (Tomey, Japan), an ocular response analyzer ORA (Reichert, USA), a confocal microscope ConfoScan-4 (Nidek, Japan) and a laser flare cell meter FC-2000 (Kowa, Japan).

Femtosecond laser-assisted intrastromal MyoRing implantation was performed on the right eye. The operation was performed under local instillation anesthesia in two stages. Stage I represented the creation of an intrastromal pocket in a corneal transplant with diameter 7.0 mm at the depth of 400 μm and an incision tunnel 1.0 mm long and 4.0 mm wide using femtosecond laser Femto Visum 1 MHz (Troitsk, Russia). At stage II the MyoRing was inserted in the corneal pocket. The diameter of MyoRing diameter was 5.0 mm, its height was 280 μm, the width was 0.5 mm. The MyoRing was centered relative to the visual axis of the patient. Observation period was 2 years.

All the procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation and with the Helsinki Declaration.

No preoperative and postoperative complications were observed. The patient noted a subjective improvement in vision the day after the operation. Mean uncorrected, corrected distance visual acuity values increased after operation and reached their final values by 6 months after surgery [Table 1]. The spherical refraction component, the average keratometry, the corneal astigmatism, the surface regularity index, the surface asymmetry index decreased after operation and reached their final values by 6 months after surgery. These parameters did not change during the observation period from 6 months to 2 years.
Table 1: Preoperative and postoperative clinical findings of the patient's right ey

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During biomicroscopy, the corneal transplant was clear; the MyoRing was centered [Figure 1].
Figure 1: Eye of patient K. the day after femtosecond laser-assisted intrastromal MyoRing implantation into a corneal transplant

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On the corneal OCT, the MyoRing was in the correct position in the deep layers of the stroma, according to the calculated depth. The minimum value of pachymetry in the central zone on the first day after operation slightly increased by 37 μm. This is due to a small swelling of the corneal stroma. After 6 months, the minimum value of pachymetry in the central zone reached preoperative values and did not change anymore.

The day after the operation the corneal hysteresis (CH) increased by 6.0%, the corneal resistance factor (CRF) increased by 11.0%. CH and CRF increased by another 7.0% 6 months after surgery. During the observation period from 6 months to 2 years, CH and CRF did not change.

The density of endothelial cells did not change during the entire observation period.

There was a slight increase in protein flow and the number of cells in the moisture of the anterior chamber on the first day after surgery. However, an increase in these indicators remained within the normal range. These indicators reached normal on the 3rd day after the operation and did not change anymore.


  Discussion Top


A keratotopogram of the right eye before surgery shows irregular astigmatism of a high degree [Figure 2]. The MyoRing implantation created in the corneal transplant an “additional limb”. Relative to the “additional limb” there was a uniform flattening of the corneal transplant. This led to a large decrease in corneal astigmatism and increased its regularity. This was confirmed by a decrease in keratometry average value, corneal astigmatism, surface regularity index and surface asymmetry index.
Figure 2: Differential keratotopogram of patient K. the day after femtosecond laser-assisted intrastromal MyoRing implantation into a corneal transplant

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The MyoRing provides the possibility of additional correction of concomitant high myopia by increasing the height and reducing the diameter of the ring. This was confirmed by a decrease in the spherical refraction component. As a result, the patient increased uncorrected and corrected distance visual acuity values.

The MyoRing created an additional “framework” in the corneal transplant, which led to an increase in its biomechanical properties. An increase in the biomechanical properties of the corneal transplant did not allow regression of the refractive result. This was confirmed by the lack of regression of clinical and functional parameters in the period from 6 to 12 months after the operation.


  Conclusion Top


Femtosecond laser-assisted intrastromal MyoRing implantation allows to correct irregular astigmatism after penetrating keratoplasty and high myopia.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Lim L, Pesudovs K, Goggin M, Coster DJ. Late onset post-keratoplasty astigmatism in patients with keratoconus. Br J Ophthalmol 2004;88:371-6.  Back to cited text no. 1
    
2.
Lisa C, Miriam G, David M, Leonardo T, Jesús M, José F. Femtosecond laser–assisted intrastromal corneal ring segment implantation for high astigmatism correction after penetrating keratoplasty. Cataract Refract Surg 2013;39:1660-7.  Back to cited text no. 2
    
3.
Kuryan J, Channa P. Refractive surgery after corneal transplant. Ophthalmology 2010;21:259-64.  Back to cited text no. 3
    
4.
Lee HS, Kim MS. Factors related to the correction of astigmatism by LASIK after penetrating keratoplasty. J Refract Surg 2010;26:960-5.  Back to cited text no. 4
    
5.
Sinitsyn MV, Pozdeyeva NA, Pashtayev NP. Comparative analysis of the intrastromal MyoRing implantation performed with the femtosecond laser. Int J Kerat Ect Cor Dis 2017;6:49-57.  Back to cited text no. 5
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1]



 

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