Efficacy of three different methods for side port incision wound sealing

PURPOSE: To evaluate wound leakage and bacteria-sized particle influx in differently corneal sealed side port incisions. METHODS: Four 1.5mm tunnel squared incisions were created in each of four cadaveric human eyes. In each cornea, one incision was left unsealed, whereas the other three incisions were sealed using a 10-0 nylon suture, cyanoacrylate glue, or stromal hydration, respectively. A Seidel and an India ink test were performed on each eye. During each Seidel test, flourescein was applied, the IOP increased from 15 to 80mmHg, and the IOP at which each incision started to leak recorded. During each India ink test, ink was placed on the eye and rinsed out with balanced salt solution (BSS). Ink penetration was then measured by planimetry at physiologic conditions and after an IOP plunge from 80mmHg to 0mmHg. RESULTS: Regardless of IOP variations, no leakage or ink inflow was observed through the glued incisions. In contrast, leakage did occur in the other three sealing methods, albeit at significantly different IOP levels in each one (p=0.013). Ink inflow occurred in these sealing methods at physiologic IOP and, to a significantly greater extent, after the IOP challenge (p<0.05). At both of these IOP conditions, the differences in ink influx among these three incision-sealing methods were deemed statistically insignificant. CONCLUSION: This study showed that glue was more effective at preventing wound leakage and bacteria-sized particle influx than other commonly used methods especially hydrosealing.

OBJETIVO: Avaliar o sinal de Seidel positivo e a penetração de tinta da Índia em incisões corneanas acessórias seladas por diferentes métodos. MÉTODOS: Quatro incisões de 1,5 x 1,5mm foram criadas em cada um dos quatro olhos provindos do banco de olhos. Em cada córnea, uma incisão foi mantida sem manipulação, enquanto que as outras três incisões foram seladas respectivamente com Nylon 10-0, cola de cianoacrilato e hidratação estromal. Foram realizados dois testes: Sinal de Seidel positivo e penetração da tinta da Índia. No primeiro, foi aplicado fluoresceína gotas e a pressão intraocular (PIO) elevada de 15 para 80mmHg. No segundo, a tinta da Índia foi aplicada sobre o olho estudado em duas situações: sob PIO fisiológica e sob variação súbita da pressão, de 80 para 0mmHg. RESULTADOS: Na incisão selada com cola, apesar da variação da PIO, não houve vazamento e nem penetração de partículas de tinta. Por outro lado, o sinal de Seidel foi positivo nas outras três incisões em diferentes níveis de PIO (p=0,013). A penetração da tinta da Índia ocorreu nestas três incisões sob pressão fisiológica e com maior extensão após a variação da PIO (p<0,05). Esta diferença, no entanto não foi considerada estatisticamente significante quando comparadas as incisões entre si. CONCLUSÃO: No presente estudo, a cola foi mais eficaz em prevenir Seidel e entrada de partículas do que outro método comumente usado especialmente, hidratação estromal.

Influence of patient race on the autcome of photorefractive keratectomy for myopia correction

Purpose: To examine the effect of patient race on clinicai outcomes following excimer kaer surgery for myopia and myopic astigmatism. Methods: A total of 116 eyes from Caucasian patients,16 eyes from Asian patients and 16 eyes from Hispanic patients who underwent PRK were evaluated retrospectively. PRK procedures were performed by the same surgeon using a 193 mm argon- fluoride excimer laser (VISX) with 160 mJ/ cmz fluence and a 6.5 Hz repetition rate at the Doheny Eye Institute. During 6 months of follow-up, changes in the uncorrected visual acuity (UCVA), refraction and spectacle-corrected visual acuity (SCVA) were evaluated. Pairwise comparisons between races were performed for age, sphere and cylinder using independent sample t tests, while UCVA and SCVA were compared using Fisher' s exact tests. The accepted level of significance for ali tests was a=0.05/3 =0.0167. Results: The only differences found were between the Asian versus Caucasian groups related to the spectacle-corrected visual acuity of 20/15 (p=0.01) and in the Asian versus Hispanic groups related to the mean cylinder (p=0.04) at 3 months postoperatively. The comparison of the mean cylinder showed a statistically significam difference between the Asian versus Hispanic groups at 6 months posto-peratively (p=0.04). After 6 months, 72.7 percent of the eyes in the Asian group, 85.7 percent of the eyes in the Hispanic group and 87.1 percent of the eyes in the Caucasian group had uncorrected visual acuity of 20/40 or better and the mean sphere andcylinder(ñSD) were:-0.55 (ñ0.88) and0.97 (ñ0.79);-0.75 (ñ 1.24) and 0.40 (ñ 0.45); -1.21(ñ 2.55) and 0.75 (ñ 0.89), respectively. Conclusion: In this study, there were no statistically significant differences between the three race groups related to the final visual outcome following photorefractive keratectomy. These prefminary results suggest that the clinicai outcomes of PRK are not significantly affected by patient race. Larger populations and longer-term studies are needed to definitely determine whether racial differences exist.

Thermokeratoplasty for the treatment of hyperopia: a clinical follow-up

Corneal curvature can be altered by shrinking stromal collagen with a retractable cautery probe tip that produces controlled thermal burns in a procedure termed hyperopic thermokeratoplasty (HTK). This procedure induces steepening of the central cornea. We performed HTK in 12 sighted eyes from eight patients placing a radical pattern of spots on the peripheral cornea, using the Fyodorov thermal unit. The number of spots and the shape of the optical zone (rounded or ovoid) was determined by a computer software provided by the manufacturer. Follow-up ranged from 24 to 54 weeks (mean of 31.50 weeks). Spherical equivalent changed from a preoperative mean of 4.10 +/- 1.12 diopters to -0.85 +/- 0.86 (P=0.001), 1.05 +/- 1.34 (P=0.001) and 3.84 +/- 1.13 diopters (P+o.16), respectively at 4,12 and 24 weeks after the surgery and at the last follow-up. The induced keratometric steepening at 4 weeks postoperatively (4.50 +/- 1.31, P+0.001), reduced to 1.04 +/- 0.43 diopters of corneal steepening at the last Follow-up (P=0.25). Uncorrected visual acuity improved at least two lines in nine eyes (75.0 percent), remained unchanged in twho eyes (16.7 percent), Eight eyes (66,6 percent) had uncorrected visual acuity equal to or better than 20/40 at the last visit. None of the patients had recurrent erosions, stromal necrosis or vascularizations. Endothelial cell counts performend six mouths after surgery in two patients that underwent unilateral surgery indicated no quantitative effects from HTK. These data support previous studies indicating that central corneal topography can be modified by heating corneal stroma in a controlled fashion. Regression of effect and induction of astigmatism limited the success of our series. Surgical correction of hyperopia includes hyperopic keratomileusis, hyperopic epikeratophakia, hexagonal keratotomy, thermokeratoplasty and more recently photorefractive keratectomy. 1-5 Thermokeratoplasty, a surgical procedure that involves heating of the corneal tissues, was initially attempted in patients with keratoconus. 6 Initial reports of success 6 were followed by reports of profound initial flattening but with subsequsnt return to preoperative topography, 7 and complications such as delayed epithelial healing, recurrent epithelial erosions, aseptic stromal necrosis and melting and vascularization 8...

Corneal topography

O sistema de topografia corneana baseada num mapa criado por um computador é útil para determinar as curvas de cada porçäo da córnea, além da área central geralmente determinada pelo ceratômetro. Ao medir 100% da superfície corneana, podemos saber em cada ponto da córnea qual o valor exato do poder de K neste ponto, e programar melhor as cirurgias para correçäo dee astigmatismo, adaptar as lentes de contacto que cabem para os operados e ceratotomia e estudar as assimetrias do astigmatismo normal

Epikeratophakia

A epiceratofacia é um procedimento cirúrgico relativamente simples, porque näo é invasivo e evita as complicaçöes encontradas com cirurgias intra-oculares. Entretanto os resultados visuais säo inferiores aos encontrados com implantes secundários. Após 6 meses, mais de 1/3 dos pacientes näo apresenta m acuidade situada entre uma linha da existente antes da Catarata, e a maioria apresenta astigmatismos de 3 ou mais dioptrias

Keratoplasty in aphakic and pseudophakic patients

A ceratopatia bolhosa da pseudofacia é hoje a principal causa de transplantes de córnea nos EEUU. A maioria destes casos apresenta lentes fixadas na íris ou lentes rígidas de câmara anterior. A cirurgia do transplante deve associar-se com a substituiçäo da lente causadora do problema com uma lente de câmara posterior, apoiada na cápsula posterior quando presente, ou fixada na íris ou sulco ciliar. A incidência de complicaçöes nos casos com lentes de câmara posterior é muito menor. Embora a maioria dos transplantes permaneça transparente, a visäo näo melhora muito, em virtude de edema macular cistóide