Femto second laser assisted wedge resection for the treatment of PMD
Year: 2024
Type: article
Abstract: Dear Editor, Recently, we published an article on air-assisted endothelium sparring wedge resection for PMD. This new technique involved the controlled injection of air in the area of the diseased cornea in order to facilitate easier separation from the surrounding tissue, similar to the big bumble technique. Following the great interest that our article on air-assisted endothelium sparring wedge resection for PMD[1] has attracted, we would like to share our experience with femtosecond laser assisted wedge resection that could minimise the risks associated with manual surgery. The implementation of femtosecond lasers in corneal surgery has resulted in the modification and modernization of several manually performed surgical procedures, offering precision and repeatability in a number of surgical interventions.[2] As femtosecond laser technology is now available in several eye units across the world, we have initially used it in an attempt to minimise the potential risks of perforation and irregular dissection whilst maintaining or even increasing the repeatability of the endothelium-sparring wedge resection, even in advanced cases of PMD. A 70-year-old male patient presented to our clinic with a long-standing diagnosis of PMD. His preoperative measurements for anterior Ks were K1: 34,10 D, K2: 48,80 D, and cylinder: 14.70 D at 8° [Fig. 1].Figure 1: Photo collage of Placido topographies. a: Preoperative topographies with K1: 34,10 D, K2: 48,80 D, and cylinder: 14.70 D at 8°. b: Postoperative topographies after femtosecond laser and CXL with K1: +37.90 D, K2: +42.03 D, and cylinder: +4.13 D at 67°We proposed surgical management by performing a wedge excision utilising femtosecond technology (VICTUS femtosecond laser platform system, version 3.2, Bausch and Lomb, Technolas Perfect Vision, Germany). The initial outer cut had the following parameters at the commencement of the operation: a depth of 80% for a 9.5 mm optical zone, an 80° thickness amplitude, and a 70° side cut angle. The second inner cut measured a 7.2 mm optical zone with an amplitude of 80°, a side cut angle of 110°, and the same depth of 80% [Fig. 2].Figure 2: Photo collage of various stages of femtosecond laser (a–c) and a schematic of the surgery’s principal (d)After two femtosecond laser incisions, a 0.3 mm wide corneal wedge was effortlessly extracted. The two vacant margins were closed using a nylon/prolene 10 zero suture. [Fig. 3].Figure 3: Photo collage of slit lamp photos and AS-OCT scans at 3 and 12 months postoperativelyThe patient continued to use lubricants frequently after completing a 10-day course of ofloxacin + dexamethasone eye drops administered postoperatively. On the first postoperative day, the cornea was clear and devoid of oedema, with well-apposed corneal margins. The use of tight sutures led to a reduction and inversion of corneal astigmatism, as evidenced by the Placid topography. Subsequently, the sutures were relaxed, resulting in an astigmatism of 4.33 D three months later [Fig. 1]. In an effort to stabilise the incision, collagen crosslinking was conducted three months after the operation.[3] A ten-minute accelerated collagen corneal cross-linking protocol (9 mW/cm2) was implemented using a procedure that has been previously documented.[4] Postoperatively, the astigmatism remained stable. The topographic measurements for anterior Ks one year later were K1: +37.90 D, K2: +42.03 D, and cylinder: +4.13 D at 67°. The utilisation of femtosecond laser-assisted wedge excision for PMD treatment is characterised by its safety, efficacy, and repeatability. By creating symmetrical and oblique incisions down to the deep stroma, femtosecond laser therapy effectively reduces the corneal ectatic region while concurrently augmenting corneal thickness in the targeted area. The procedure improves both corneal astigmatism and the patient’s best-corrected visual acuity. The implementation of a femtosecond laser enables enhanced accuracy while minimising the risk of perforation; thus, the intrastromal air injection is not necessary to assist with smooth lamellar dissection. To enhance and fortify the rigidity of the corneal structure, we integrated collagen crosslinking into our procedure. We opted for a less invasive strategy by eliminating a 0.3 mm corneal crescent, which proved to be adequate. Further research is required to ascertain the optimal thickness and morphology of the tissue that needs to be excised. Cataract surgery and toric IOL implantation effectively resolved the residual stable refractive defects in our patient, thereby establishing this surgical approach as a safe and effective treatment for mild to moderate PMD. Femtosecond laser-assisted wedge resection may be of particular interest to physicians who have access to a femtosecond laser platform. The procedure demonstrates a high level of accuracy and efficacy, which can be further enhanced with the use of CXL in the inferior part of the ectatic cornea. Further research may help optimise the laser parameters and improve the efficacy of the procedure. 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.
Source: Indian Journal of Ophthalmology
Institution: Birmingham and Midland Eye Centre
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W4403781911