Title: Long‐term follow‐up on intracorneal ring segment inserted for the correction of myopia
Abstract:Editor, Intracorneal ring (ICR, consisting of one segment) or intracorneal ring segments (ICRS, consisting of two semi-rings) refer to plastic ring arcs inserted into the corneal stroma (Ertan A & Col...Editor, Intracorneal ring (ICR, consisting of one segment) or intracorneal ring segments (ICRS, consisting of two semi-rings) refer to plastic ring arcs inserted into the corneal stroma (Ertan A & Colin J 2007). ICR/ICRS can be used for: Correction of low grades of myopia (Schanzlin et al. 1997) (−1 to −4 D) (Ertan A & Colin J 2007). Treatment of keratoconus, sometimes as an alternative to transplantation. Correction of residual myopia after laser treatment of severe myopia. Intacs, Ferrara and Bisantis (Ertan A & Colin J 2007) are the three existing ring models. Each ring consists of two plastic semi-ring segments (ICRS), because they are easier to insert than an ICR. The semi-rings are placed in the corneal stroma mimicking a full circle. The ICR segments measure 0.24–0.45 mm in thickness and cause a reshaping and flattening of the central part of the cornea (Burris et al. 1993; Ertan A & Colin J 2007). The inner diameter of the segments is 6.77 mm. At 12 o’clock a 1 mm radial incision of approximately 70% of the corneal thickness on the flattest axis (Ertan A & Colin J 2007) is made. The mid-stromal channels are formed with special arcuate dissectors. The central part of the cornea remains untouched. There is a positive effect on vision immediately after the operation. Visual acuity improves further over the next couple of days. Even further improvement can be seen 6–12 months after the operation. A 46-year-old man had been myopic since the age of 14. Since the age of 21 the myopia remained stable at about −3 D. He suffered from recurrent headaches when wearing glasses and had the perception of poorer vision when wearing contact lenses. In November 1992 his eyes were found to be myopic (−3 D) and otherwise normal. In December 1992 he had an intracorneal ring (ICR) inserted in the right eye without complications. The first few days after the operation the patient was sensitive to light; after 6 days he had no complaints; and 13 days after the operation his visual acuity was 1.0 with a correction of −1 D. During the following 16 years the visual acuity was always 0.8 or better with correction. The left eye was treated successfully with excimer laser surface ablation in 1994. Considering his age and the residual myopia in the right eye, the aim was −0.5 to −1.0 D (1, 2). The ICR segment in situ nearly 16 years after insertion. Visual acuity and correction before the operation (11.11.92), shortly after insertion of ICR (06.12.92) and, subsequently, at follow-up. In 2008, visual acuity on the ICR-treated right eye was 0.6 uncorrected, 1.0 corrected. Slit-lamp examination revealed a clear cornea and no deposits along the ring. There was no sign of infection or inflammation. IOP was 17 mmHg, central corneal thickness (CCT) 0.56 mm and endothelial cell density approximately 2400/mm2 (3, 4). Corneal cell density in the right eye, nearly 16 years after insertion of ICR. Corneal cell density in the left eye, 15 years after excimer laser treatment. To this day visual acuity is ≥ 1.0 in both eyes with minor correction, and no complications of any kind have occurred. ICR has been stable for almost 16 years. The patient wears glasses only when driving a car or watching television. He has no visual problem in either eye. An important advantage of ICRS is that the operation is reversible, i.e. the ring can be removed or replaced if necessary (Asbell et al. 2001). The main problem with ICRS is that only low degrees of myopia can be corrected with the procedure (Ertan A & Colin J 2007). ICRS is a myopia-reducing technique that has a stable long-term effect. The technique should not be forgotten but in future it probably has a place only in the treatment of keratoconus.Read More
Publication Year: 2009
Publication Date: 2009-06-26
Language: en
Type: letter
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 1
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Title: $Long‐term follow‐up on intracorneal ring segment inserted for the correction of myopia
Abstract: Editor, Intracorneal ring (ICR, consisting of one segment) or intracorneal ring segments (ICRS, consisting of two semi-rings) refer to plastic ring arcs inserted into the corneal stroma (Ertan A & Colin J 2007). ICR/ICRS can be used for: Correction of low grades of myopia (Schanzlin et al. 1997) (−1 to −4 D) (Ertan A & Colin J 2007). Treatment of keratoconus, sometimes as an alternative to transplantation. Correction of residual myopia after laser treatment of severe myopia. Intacs, Ferrara and Bisantis (Ertan A & Colin J 2007) are the three existing ring models. Each ring consists of two plastic semi-ring segments (ICRS), because they are easier to insert than an ICR. The semi-rings are placed in the corneal stroma mimicking a full circle. The ICR segments measure 0.24–0.45 mm in thickness and cause a reshaping and flattening of the central part of the cornea (Burris et al. 1993; Ertan A & Colin J 2007). The inner diameter of the segments is 6.77 mm. At 12 o’clock a 1 mm radial incision of approximately 70% of the corneal thickness on the flattest axis (Ertan A & Colin J 2007) is made. The mid-stromal channels are formed with special arcuate dissectors. The central part of the cornea remains untouched. There is a positive effect on vision immediately after the operation. Visual acuity improves further over the next couple of days. Even further improvement can be seen 6–12 months after the operation. A 46-year-old man had been myopic since the age of 14. Since the age of 21 the myopia remained stable at about −3 D. He suffered from recurrent headaches when wearing glasses and had the perception of poorer vision when wearing contact lenses. In November 1992 his eyes were found to be myopic (−3 D) and otherwise normal. In December 1992 he had an intracorneal ring (ICR) inserted in the right eye without complications. The first few days after the operation the patient was sensitive to light; after 6 days he had no complaints; and 13 days after the operation his visual acuity was 1.0 with a correction of −1 D. During the following 16 years the visual acuity was always 0.8 or better with correction. The left eye was treated successfully with excimer laser surface ablation in 1994. Considering his age and the residual myopia in the right eye, the aim was −0.5 to −1.0 D (1, 2). The ICR segment in situ nearly 16 years after insertion. Visual acuity and correction before the operation (11.11.92), shortly after insertion of ICR (06.12.92) and, subsequently, at follow-up. In 2008, visual acuity on the ICR-treated right eye was 0.6 uncorrected, 1.0 corrected. Slit-lamp examination revealed a clear cornea and no deposits along the ring. There was no sign of infection or inflammation. IOP was 17 mmHg, central corneal thickness (CCT) 0.56 mm and endothelial cell density approximately 2400/mm2 (3, 4). Corneal cell density in the right eye, nearly 16 years after insertion of ICR. Corneal cell density in the left eye, 15 years after excimer laser treatment. To this day visual acuity is ≥ 1.0 in both eyes with minor correction, and no complications of any kind have occurred. ICR has been stable for almost 16 years. The patient wears glasses only when driving a car or watching television. He has no visual problem in either eye. An important advantage of ICRS is that the operation is reversible, i.e. the ring can be removed or replaced if necessary (Asbell et al. 2001). The main problem with ICRS is that only low degrees of myopia can be corrected with the procedure (Ertan A & Colin J 2007). ICRS is a myopia-reducing technique that has a stable long-term effect. The technique should not be forgotten but in future it probably has a place only in the treatment of keratoconus.