Tuck-and-pull technique for posterior chamber phakic intraocular lens explantation.

The tuck-and-pull technique was developed for practical and safe explantations of posterior chamber phakic intraocular lenses (PCPIOLs). In this technique, after the creation of a side port, viscoelastic (or OVD [ophthalmic viscosurgical device]) is initially injected behind the PCPIOL to widen the space between PCPIOL and the crystalline lens. The old incisions can be used after recent implantations rendering the enlargement of the main incision unnecessary. After additional OVD over and under the PCPIOL, the haptic is tucked by a chopper and pulled through the main incision with a single maneuver. The haptic is grasped by two suture forceps and explanted with a "hand-to-hand" maneuver. The tuck-and-pull technique provided high protection of the corneal endothelium, crystalline lens, anterior chamber structures, and the PCPIOL itself. This technique is a practical, easy, and safe approach for explantations of all PCPIOL types, whatever the reason for its explantation may be.

Management of post laser in situ keratomileusis ectasia with simultaneous topography guided photorefractive keratectomy and collagen cross-linking.

A thirty-nine year old man was referred to our institute due to progressive decreased visual acuity five years after bilateral Laser in situ Keratomileusis (LASIK). Topography revealed signs of post - LASIK ectasia. Patients' left eye was treated with simultaneous Topography Guided Photorefractive Keratectomy (PRK) followed by Corneal Collagen Cross Linking (CXL). Twelve months after the combined procedure both uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) showed significant improvement while topographic findings revealed an improvement of the astigmatic pattern. All higher order aberrations showed a significant decrease twelve months postoperatively. Combined topography guided PRK and corneal cross linking could represent an alternative treatment for post - LASIK ectasia.

Corneal collagen cross-linking outcomes: review.

Keratoconus is a condition characterized by biomechanical instability of the cornea, presenting in a progressive, asymmetric and bilateral way. Corneal collagen cross-linking with riboflavin and UVA (CXL) is a new technique of corneal tissue strengthening that combines the use of riboflavin as a photo sensitizer and UVA irradiation. The studies showed that CXL was effective in halting the progression of keratoconus over a period of up to four years. The published studies also revealed a reduction of max K readings by more than 2 D, while the postoperative SEQ was reduced by an average of more than 1 D, and refractive cylinder decreased by about 1 D. No eyes lost any line of BCDVA. Moreover, there was no significant decrease in endothelial cell density. It was also found that CXL treatment was effective with reducing corneal and total wavefront aberrations. Corneal cross-linking has also led to an arrest and/or even a partial reversal of keratectasia in the treatment of iatrogenic ectasia after excimer laser ablation. A primary intervention such as CXL should be considered to potentially increase the biomechanical stability of the corneal tissue and postpone the need of lamellar or penetrating keratoplasty.

Corneal collagen cross-linking.

Corneal collagen cross-linking (CXL) with riboflavin and ultraviolet-A (UVA) is a new technique of corneal tissue strengthening by using riboflavin as a photosensitizer and UVA to increase the formation of intra and interfibrillar covalent bonds by photosensitized oxidation.Keratocyte apoptosis in the anterior segment of the corneal stroma all the way down to a depth of about 300 microns has been described and a demarcation line between the treated and untreated cornea has been clearly shown. It is important to ensure that the cytotoxic threshold for the endothelium has not been exceeded by strictly respecting the minimal corneal thickness. Confocal microscopy studies show that repopulation of keratocytes is already visible 1 month after the treatment, reaching its pre-operative quantity and quality in terms of functional morphology within 6 months after the treatment. The major indication for the use of CXL is to inhibit the progression of corneal ectasias, such as keratoconus and pellucid marginal degeneration. CXL may also be effective in the treatment and prophylaxis of iatrogenic keratectasia, resulting from excessively aggressive photoablation. This treatment has also been used to treat infectious corneal ulcers with apparent favorable results. Combination with other treatments, such as intracorneal ring segment implantation, limited topography-guided photoablation and conductive keratoplasty have been used with different levels of success.

Ultra B2 - Promoção de ligações covalentes do colágeno corneal (Corneal cross-linking) no tratamento de ceratocone: resultados preliminares / Corneal Cross-linking for the treatment of keratoconus: preliminary results

OBJETIVO: Apresentar os resultados visuais e ceratométricos, seis meses após tratamento foto-terapêutico com luz ultravioleta (UV) e vitamina B2 (Ultra B2), em pacientes com ceratocone progressivo. MÉTODOS: Vinte e cinco olhos de 20 pacientes (15 homens e 5 mulheres) com ceratocone progressivo, determinado pelo aumento de curvatura em exames seriados de topografia corneal, nos últimos seis meses foram avaliados. Acuidade visual não corrigida (UVA), acuidade visual melhor corrigida com óculos (BSCVA), equivalente esférico (SEQ), cilindro refrativo manifesto e a curvatura máxima (max K) pré e pós-operatórios (1, 3 e 6 meses) foram determinadas. Todos os pacientes foram submetidos ao tratamento Ultra B2 usando riboflavina (vitamina B2) e a luz ultravioleta (UV, 370 nm). O epitélio corneal foi removido após assepsia, colocação de blefarostato e anestesia tópica com proparacaína, por meio de solução de álcool hidratado (20 por cento) utilizada por 30 segundos. A córnea foi saturada com vitamina B2 por 15 minutos; em seguida, foi irradiada por luz UV por 30 minutos. Ao final do procedimento, foi colocada lente de contato terapêutica (LCT), mantida até a epitelização total. RESULTADOS: Houve melhora na UVA após o primeiro mês (de 0,15 ± 0,15 para 0,23 ± 0,20), com contínua mudança no terceiro e sexto mês pós-operatório, atingindo a diferença estatisticamente significante nesse período (p=0,025 e p=0,037 respectivamente). BSCVA melhorou de 0,41 ± 0,27 para 0,49 ± 0,29 no sexto mês, sem atingir a diferença estatisticamente significante. A progressão do ceratocone após o procedimento não foi notada em nenhum paciente, em comparação com o avanço topográfico nos 6 meses precedentes. Após 6 meses do procedimento, max K diminuiu em mais que 2,00 D (de 53,02 ± 8,42 para 50,88 ± 6,05 D), SEQ em menos que 1 D (de -3,27 ± 4,08 para -2,68 ± 3,02 D) e o cilindro refrativo em menos que 0,5 D (de -2,29 ± 1,77 para -1,86 ± 0,92), sem atingir diferença estatisticamente...

PURPOSE: To present early visual and keratometric results for corneal cross-linking with riboflavin and UV irradiation in patients with progressive keratoconus. METHODS: Twenty-five eyes of twenty patients (15 males and 5 females) with a progressive keratoconus in the previous 6 months were followed. Unaided visual acuity (UVA), best spectacle corrected visual acuity (BSCVA), spherical equivalent (SEQ), manifest cylinder, and maximal corneal curvature (max K) values were followed at 1, 3 and 6 months. All patients were submitted to corneal cross-linking using riboflavin (vitamin B2) as the photosensitizer and ultraviolet light (UV, wavelength 370 nm). Epithelium was removed with 20 percent alcohol, cornea was soaked with vitamin B2 for 15 min, and then irradiated with UV light for 30 min, after which a bandage contact lens (BCL) was placed. RESULTS: UVA increased after one month (from 0.15 ± 0.15 to 0.23 ± 0.20), and went on increasing at 3 and 6 months, reaching statistical significance (p=0.025 e p=0.037, respectively). BSCVA increased from 0.41 ± 0.27 to 0.49 ± 0.29 at month six, without reaching statistical significance at any time point. Progression of keratoconus stopped in all patients, in contrast with progression in all of them in the six-month period prior to the surgery. Max K decreased by more than 2 D (from 53.02 ± 8.42 to 50.88 ± 6.05 D), SEQ less that 1 D (from -3.27 ± 4.08 to -2.68 ± 3.02 D), while refractive cylinder decreased less than 0.5 D (from -2.29 ± 1.77 to -1.86 ± 0.92 D), without reaching a statistically significant difference. None of the eyes lost any line of BSCVA, 12 maintained the preoperative BSCVA, 7 gained one line, 5 gained two lines, and 1 patient gained three lines of BSCVA. CONCLUSIONS: Corneal cross-linking with riboflavin and UV light seems to be a safe (no loss of BSCVA) and effective (anatomical and optical properties maintained) procedure, which has shown to stop the progression of the keratoconus...