Ocular Surface Surgery Research Articles

Utilização de adesivo de fibrina em cirurgias oftalmológicas

To evaluate the use of fibrin glue and its complications in different ophthalmic surgeries. A retrospective and non-comparative case series study. 161 eyes were evaluated. The mean age was 51.8 years. Fibrin glue (Beriplast--Aventis Behring, Germany) was used in all patients for tissue adherence or incisional closure. Main preoperatives diseases were pterygium (76 patients), superior limbic keratoconjunctivitis (4 patients), limbal tumor (4 patients), conjunctivochalasis (21 patients), bullous keratopathy (31 patients), limbal stem cell deficiency (7 patients), alkali injury (6 patients), Stevens-Johnson syndrome (2 patients), cataract (5 patients) and glaucoma (5 patients). Complications occurred in 28 patients (17.4%). Detachment of the fixed tissue and granulomatous foreign body reaction were the main complications. Detachment occurred in 10 cases (5.6%) (7 in amniotic membrane transplantation in bullous keratopathy, 2 in autologous conjunctival grafting for pterygium surgery, 1 in autologous limbal transplantation in a Stevens-Johnson syndrome). Granulomatous foreign body reaction was described in 9 patients (5.6%) (5 in amniotic membrane transplantation due to acute alkali injury, 1 in autologous limbal graft due to chronic burn injury, and 3 in autologous conjunctival transplant due to pterygium surgery). All the complications described occurred in the first week after surgery. Despite the limitations related to the retrospective and non-comparative setting, this study suggests that the use of fibrin glue seems to be safe and effective for tissue fixation or incisional closure presenting low rates of complications in ocular surface and anterior segment surgeries.

Long‐term visual prognosis of corneal and ocular surface surgery in patients with congenital aniridia

To evaluate the long-term visual prognosis of corneal and ocular surface surgery in patients with congenital aniridia. Retrospective comparative interventional case series on 88 eyes of 45 patients with congenital aniridia treated and/or operated on from 1956 to present. Corneal and ocular surface findings were identified and patients were classified into operated (group I) or not operated (group II). Long-term best-ever best-corrected visual acuity (BCVA), final BCVA and long-term delta BCVA (long-term best-ever BCVA - final BCVA) were recorded and compared between the two groups, and between the limbal transplant (LT) (group I-A) and the penetrating keratoplasty (PK) (group I-B) patients. Postoperative results were also compared. Limbal insufficiency was present in 58% of eyes and dense central corneal opacities were present in 27% of eyes. As a primary surgery, limbal allograft was performed in 10 eyes and PK in 13 eyes. The mean long-term follow-up times were 23 years in group I and 16 years in group II. The mean long-term delta BCVA was 0.032 in group I and 0.028 in group II. Comparisons of the VA means were insignificant (long-term best-ever, final BCVA and long-term delta BCVA). When comparing the LT and PK groups, mean long-term delta BCVA was 0.0328 in group I-A and 0.0382 in group I-B. Mean postoperative delta BCVA was 0.028 in group I-A and 0.048 in group I-B. We found no statistical significance between the LT and the PK groups as regards long-term postoperative BCVA results. Long-term visual prognosis does not differ whether or not the patient undergoes surgery for aniridic keratopathy. LT and PK have comparable results over 5 years of follow-up because of the eventual failure of transplanted allografts.

Sutureless Amniotic Surgery for Pterygium

P terygium is one of the oldest pathologies known to ophthalmologists. Surgery for this condition can range from simple excision to techniques with exotic detail and meticulous maneuvers with task-specific instruments beckoning an era of raised expectations and cosmetic outcomes in the field of ocular surface surgery itself. In my previous publications, I had emphasized on complete removal along with amniotic grafting as a key concept for success. The part of the pterygium that is visible is only the tip of the iceberg (iceberg concept). By removing only this visible portion, the main pathology with its tentacles is not addressed and remains hidden under the conjunctiva. Theories about the etiology of pterygia are diverse and range from hereditary, neurotrophic, angioplastic, and immunologic causes to ultraviolet light exposure. Regardless of the cause, the result is elastotic degeneration with vesiculation of Bowman’s membrane in the cornea and formation of epithelial islets (Fuchs patches) as cysts around the pterygium (seen as glove-finger appearance on histopathologic study). Anatomically, the pterygium is composed of several segments, including Fuchs patches and Stocker line (the iron line), the hood, the head, the body, and the superior and inferior edges. Having previously classified pterygia into 4 categories, I have continuously studied the presentations and the outcomes in improving the surgical approach and outcomes over the years to add an additional way to classify the pterygium based on the adhesion of the head to the ocular surface and vascularity along with the draw test on the cornea. Pterygia can therefore have the following: Head/neck adhesion. Peripheral or central adhesion. In cases of peripheral adhesion, the pterygium easily peels off the cornea. Vascularity. Engorged, tortuous vessels and simultaneous conjunctival fold contracture signifies a more aggressive pterygium. This same concept can be used to determine outcomes postoperatively. Draw test. On tugging on the cornea, some pterygia may be small but outright gritty and deep into the cornea resulting in thin cornea when removed. Preparation for this before surgery helps plan a smooth outcome (amniotic graft itself can be used as a lamellar fill). Also, removal of these pterygia is more difficult from the corneal surface. Amniotic membrane. The advantages of the commercially available membrane are that there is no immune reaction, and it has anti-inflammatory functions, is antiadhesive and antibacterial, encourages epithelial differentiation and growth, and has an antitissue growth factor effect.

Amniotic membrane preservation in RPMI‐1640 medium – 5 years experience

Abstract Purpose: Present amniotic membrane preservation method using RPMI‐1640 medium and brief analysis of performed surgeries. Methods: Amniotic memmbrane preservation and transplantation surgeries in Vilnius University Hospital Center of eye Diseases was started at the end of 2001. Till the June 2007 amniotic membrane was prepared from 5 placentas obtained during the caesarean delivery. The essence of the preparation of the amniotic membrane was as described by H.Dua and other authors. However, because of the supply disturbances in our hospital instead of the traditional mediums we used RPMI‐1640 medium. Before the cuting amniotic membrane to a small pieces we put the whole membrane in RPMI‐1640 medium with high concentration of antibiotics and antifungals and stored in +5ºC temperature for 24 hours. After that amniotic membrane we put on paper cut to small peaces and stored in RPMI‐1640 medium and glicerol in ‐ 80°C. Results: Before the surgery amniotic membrane was warmed in room temperature. No damage of the structure was observed. Hystopathological slides of membrane samples were performed. Preservation medium specimens for microbiological investigation were taken. From all 5 placentas series no growth was observed. Amniotic membrane was used during 179 ocular surface surgeries. Conclusions: 1. RPMI‐1640 medium can be successfully used for amniotic membrane preservation. 2. Before final frosting in ‐ 80°C, 24 hours in high concentration of antibiotics and antifungals can guaranty high impregnation of amniotic membrane with antimicrobial medication. 3. After preservation in RPMI‐ 1640 medium amniotic membrane retains it appearance, clarity and physical durability.

Defensin Expression in Tears in Response to Ocular Surface Surgery and Corneal Wounding

The optical behaviour of a hitherto unexplored compound GdScO3 is investigated. The orthorhombic GdScO3 was obtained by gel combustion synthesis which yielded phase pure product at temperatures as low as 650 °C. Despite the absence of any activator, undoped GdScO3 showed distinct excitation and emission spectra attributed to various shallow and deep defects present in the system. Annealing temperature altered the emission characteristics which exhibited prevalence of more deep defects on increasing the temperature. An efficient host to activator energy transfer was observed in the Eu3+ and Tb3+-doped GdScO3. However, an incomplete energy transfer to Dy3+ resulted in an extensive host emission band along with characteristic Dy3+ emission peaks. Ab-initio theoretical studies suggested that partial energy transfer to Dy3+ could be ascribed to contribution of Dy 4f orbitals to valence band predominantly formed by O 2p orbitals which enhances the probability of back transfer. Time resolved studies yielded single lifetimes for Eu3+ and Tb3+ but two lifetimes for Dy3+. The fact that the lifetime for excited states of Dy3+ was ∼10 times lesser than Eu3+ and Tb3+ also supported the existence of alternate pathways for the excited state of Dy3+. Various photophysical parameters were determined for GdScO3:Eu composition. Co-doping of all the three activators (Eu, Tb and Dy) led to a near white light emission suggesting its applicability as white-light and muticolored phosphors.

Proteomic analysis of human tears: defensin expression after ocular surface surgery.

Human tear protein profiles were monitored by surface enhanced laser desorption/ionization-time-of-flight mass spectrometry ProteinChip technology (SELDI-TOF ProteinChip) and liquid chromatography-mass spectrometry (LC-MS). Tears were collected from 21 patients scheduled for surgery to remove an ocular surface neoplasm prior to surgery (day 0) and on days 1, 3, and 30 postoperatively. Using this proteomic approach, we verified that three human alpha-defensins (HNP-1, HNP-2, and HNP-3) were significantly up-regulated in their expression after surgery and that their levels decreased to approximately normal by day 30 by which time healing was complete. Further confirmation of the identity of the alpha-defensins in human tears was made by LC purification, trypsin digestion, and ESI-MS/MS analysis of their tryptic digests. The concentrations of HNP-1 and HNP-2 were determined and shown to be markedly increased after ocular surface surgery. The results of the study suggest that human alpha-defensins HNP-1, HNP-2, and HNP-3 are up-regulated after surgery, and may in addition to their antimicrobial properties have an important role in wound healing.