Clinical Outcomes of Femtosecond Laser-assisted Implantation of 325-Degree Versus 340-Degree Arc Length Intracorneal Ring Segments in Naive Keratoconic Eyes

Amir Faramarzi; Kiana Hassanpour; Marjan Mazouchi; Bahram Einollahi; Sepehr Feizi; Hamed Esfandiari; Mohammad-Mehdi Sadoughi; Majid Moshirfar

doi:10.18502/jovr.v18i4.14545

Clinical Outcomes of Femtosecond Laser-assisted Implantation of 325-Degree Versus 340-Degree Arc Length Intracorneal Ring Segments in Naive Keratoconic Eyes

J Ophthalmic Vis Res. 2023 Nov 30;18(4):369-378. doi: 10.18502/jovr.v18i4.14545. eCollection 2023 Oct-Dec.

Authors

Amir Faramarzi^{1

2}, Kiana Hassanpour^{1

2}, Marjan Mazouchi¹, Bahram Einollahi², Sepehr Feizi^{1

2}, Hamed Esfandiari³, Mohammad-Mehdi Sadoughi^{1

2}, Majid Moshirfar⁴

Affiliations

¹ Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
² Department of Ophthalmology, Labbafinejad Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
³ Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, USA.
⁴ John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, Salt Lake City, UT, USA.

Abstract

Purpose: To evaluate and compare clinical outcomes after femtosecond laser-assisted implantation of 325-degree versus 340-degree arc length intracorneal ring segments (ICRS) in eyes with keratoconus (KCN).

Methods: In this prospective non-randomized interventional case series, 23 eyes of 21 patients diagnosed with KCN, underwent femtosecond laser-assisted implantation of two types of ICRS, which included a 325-degree ICRS (Group 325) and a 340-degree ICRS (Group 340). The primary outcome measures were uncorrected distance visual acuity (UDVA), and the secondary outcome measures included corrected distance visual acuity (CDVA), sphere, cylinder, mean refractive spherical equivalent (MRSE), keratometry, vectorial change in corneal astigmatism, and the location of maximum keratometry relative to the corneal apex. The study groups were compared using the primary and secondary outcome measures obtained at postoperative months six and 12.

Results: Groups 325 and 340 consisted of 10 and 13 eyes, respectively. The two groups were comparable in terms of parameters measured preoperatively. On comparison to the baseline values, both study groups exhibited a significant increase in UDVA and CDVA measured at postoperative month six (Ps $<$ 0.05) and a significant decrease in the sphere, cylinder, spherical equivalent refraction, and keratometry readings measured at postoperative months six and 12 (Ps $<$ 0.05). No significant differences were observed between the two groups in terms of visual, refractive, and keratometric outcomes at any time point. No intraoperative or postoperative complications were observed in any of the study groups.

Conclusion: Both the 325-degree ICRS and the 340-degree ICRS effectively and equally improved visual, refractive, and keratometric outcomes in keratoconic eyes.

Keywords: Femtosecond Laser; Keratoconus; Intrastromal Corneal Ring Segment.