The results of the fundus examination were normal in both eyes. Intraocular pressure, evaluated by Goldmann applanation tonometry, was 12 mmHg in both eyes. A noncontact endothelial specular microscopy (KONAN Medical Inc., Model NSP 9900, Hyogo, Japan) recorded endothelial cell densities of 2294 cells/mm 2 in the right eye and 2545 cells/mm 2 in the left eye. The thinnest corneal thickness was 486 μ in the right eye and 499 μ in the left eye. A corneal topography obtained by Pentacam (Pentacam, OCULUS GmbH, Wetzlar, Germany) showed an irregular astigmatism with inferior corneal steepening (Figures 1 and 2). In the left eye, UDVA and BCDVA were 8/40 and 12/20, respectively, with a correction of +1.00 −4.00 × 105. In the right eye, UDVA and BCDVA were 12/40 and 16/40, respectively, with a correction of −1.00 −3.00 × 85. The first patient was a 35-year-old contact lens-intolerant woman with bilateral PMD who had reported a progressive impairment of vision for the past 6 years. At the end of the treatment, a therapeutic bandage soft contact lenses were applied for one-week period, and an antibiotic regimen of moxifloxacin (Vigamox %0.5, Alcon, Fort Worth, Texas, USA) drops four times a day for 2 weeks and topical corticosteroid (dexamethasone, Dexa-sine Se 0.4 mL/1.3 mg, Liba, Istanbul, Turkey) drops twice a day for 3 weeks was administered. Patients and MethodsĪfter signing an informed consent form and receiving topical anesthetic riboflavin UVA-induced, a corneal collagen CXL was performed in the following stages: pilocarpine 2% drops for 30 minutes preoperatively topical anesthesia with proparacaine HCl 0.5% drops (Alcaine, Alcon, Fort Worth, Texas, USA) before epithelial removal corneal mechanical epithelial scraping of an area 9 mm in diameter preirradiation riboflavin solution (Ricrolin SOOFT Italia S.p.A., Montegiorgio, Italy) applied every 3 minutes for 30 minutes exposure to a solid-state UVA illuminator (CBM, Vega CSO, Florence, Italy) for 30 minutes and irradiation of a slightly inferiorly decentered area 9 mm in diameter and approximately 1 mm from the limbus (energy delivered at 3 mW/cm 2). In this study we present the long-term results of corneal collagen CXL with riboflavin and UVA irradiation in the eyes of two patients affected by PMD. Ĭorneal collagen cross-linking (CXL) with riboflavin and ultraviolet-A (UVA) light is a corneal tissue strengthening technique, which uses riboflavin as a photosensitizer and UVA to increase the formation of intra- and interfibrillar covalent bonds by photosensitized oxidation. Surgical options include intrastromal corneal rings, thermocauterization, and keratoplasty. Nonsurgical approaches to the management of PMD include spectacles and contact lenses. Patients present with a decrease of visual acuity in their thirties to fifties because of high and irregular astigmatism.
A 1-2 mm margin of normal cornea lies between the thinning and the limbus. It is characterized by a peripheral band of thinning, usually occurring in the inferior quadrant in a crescentic fashion. Pellucid marginal degeneration (PMD) is a rare, idiopathic, bilateral, progressive noninflammatory thinning corneal disorder. CXL is a safe tool for the management of PMD, and it can help to stop the progression of this disease. No complications were recorded during or after the treatment. Patient 2’s right eye showed an improvement in his BCDVA, from 18/20 to 20/20 in 43 months, and his left eye improved from 16/20 to 18/20 in 22 months. The right eye of Patient 1 showed an improvement in her BCDVA, from 16/40 to 18/20 in 15 months, and her left eye improved from 12/20 to 18/20 in 20 months. Patient 1 was a woman, aged 35, and Patient 2 was a man, aged 33.
We have pre- and postoperatively evaluated uncorrected distance visual acuity (UDVA), best corrected distance visual acuity (BCDVA), corneal topography (Pentacam), specular microscopy, and pachymetry. Of the eyes, three had only CXL treatment and one had CXL treatment after an intrastromal corneal ring segment implantation.
This study involved the retrospective analysis of 4 eyes of 2 patients with PMD that underwent CXL treatment. To report the long-term results of corneal collagen cross-linking (CXL) with riboflavin and ultraviolet-A irradiation in 4 eyes of 2 patients affected by pellucid marginal degeneration (PMD).
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