Comparison of topographic corneal irregularity after LASIK and intrastromal corneal ring segments in the same patients.

PURPOSE: To retrospectively compare the irregularity of the corneal surfaces of 14 patients after LASIK in 1 eye and placement of intrastromal corneal ring segments (ICRS) in the other eye. METHODS: In a within-patient comparison, Orbscan corneal topography was used to retrospectively compare the corneal surface irregularity of LASIK-treated and ICRS-treated eyes at an outpatient tertiary-care ophthalmology clinic in Sao Paulo, Brazil. For the anterior corneal surface, irregularity measurements were compared for both the central and peripheral areas of the cornea. The differences between each group were analyzed for statistical significance. RESULTS: The corneal surfaces of eyes treated with ICRS were found to be more irregular than the corneal surfaces of eyes treated with LASIK, the mean irregularity being 1.91 for LASIK-treated eyes and 3.12 for ICRS-treated eyes in the anterior corneal surface and 0.51 for LASIK-treated eyes and 0.87 for ICRS-treated eyes in the posterior corneal surface. A statistically significant difference was noted only in the posterior surfaces. CONCLUSIONS: When measured with Orbscan topography, ICRS-treated eyes show more corneal surface irregularity than LASIK-treated eyes. The difference in outcome for the two types of treatment may be due to the mechanical effect of the ICRS on the shape of the cornea.

Cell cycle regulators at the ocular surface.

The ocular surface provides an outstanding model to examine the regulation of the proliferative cell cycle. Cells within the cornea and conjunctiva exhibit a wide range of proliferative abilities ranging from the rapidly proliferating cells in the basal cell layer of the epithelium to the quiescent keratocytes and endothelial cells. In this review, dedicated to Dr David Maurice, we will discuss four families of proteins known to regulate the cell cycle. These families include: (1) the cyclins; (2) the CIP/KIP family of cell cycle inhibitors--consisting of p21, p27, and p57; (3) the INK4 family of cell cycle inhibitors--including p16, p15, p18, and p19; and (4) the retinoblastoma family--consisting of pRb, p107, and p130. Members of all of these families have been localized in various cells in the ocular surface. We will discuss how these proteins are involved in regulating cell proliferation both in normal homeostasis and during wound healing.

Hyperopic laser-assisted in situ keratomileusis for radial keratotomy induced hyperopia.

PURPOSE: To evaluate hyperopic laser in situ keratomileusis (H-LASIK) for radial keratotomy (RK)-induced hyperopia. DESIGN: Noncomparative interventional retrospective nonconsecutive case series. PARTICIPANTS: Sixty-nine eyes of 47 patients who had undergone RK and were seen with induced hyperopia. METHODS: H-LASIK was performed with an excimer laser. MAIN OUTCOME MEASURES: The mean refractive error, in spherical equivalents (SE), uncorrected visual acuity (UCVA), and best spectacle-corrected visual acuity (BSCVA) before and after H-LASIK are reported. Safety was analyzed using a mean follow-up time of 6.6 plus minus 3.24 months. RESULTS: Preoperative mean SE was +3.4 plus minus 1.6 diopters (D). Postoperative mean SE was -0.32 plus minus 1.2 D. A high percentage of eyes (79.7%; n = 55) were between plus minus1.0 D of emmetropia and 88% within plus minus 2.0 D. Preoperative BSCVA was 20/20 in 53.6% of eyes (n = 37) and 20/40 or better in 100% (n = 69). Postoperative BSCVA was 20/20 in 55% of eyes (n = 38) and 20/40 or better in 95.6% (n = 66) of eyes. Preoperative UCVA was less-than-or-equal20/50 in 52 cases (75.4%). Postoperative UCVA was 20/20 in 13 cases (18.8%) and greater-than-or-equal20/40 in 45 cases (65.2%). Four eyes lost 2 Snellen lines because of epithelial ingrowth in the interface (n = 3) and diffuse lamellar keratitis (Sands of the Sahara syndrome; n = 2). One of the eyes with Sahara syndrome also had epithelial ingrowth and flap necrosis. Thirteen eyes lost 1 Snellen line, and 50 eyes maintained or gained Snellen lines. The only intraoperative complication was incision opening (n = 8) while the flap was lifted; there were no further complications. These patients did not lose any Snellen lines of their BSCVA. CONCLUSIONS: H-LASIK can be used successfully to correct RK-induced hyperopia.

Ceratoplastia lamelar profunda com viscodissecçäo da membrana de Descemet / Deep lamellar keratoplasty with viscodissection of Descemet's membrane

Objetivo: Avaliar a eficácia da técnica de ceratoplastia lamelar profunda preservando a membrana de Descemet e as células endoteliais do paciente, com a utilizaçäo de botäo esclero-corneano. Métodos: Foram realizadas 14 ceratoplastias lamelares com viscodissecçäo da membrana de Descemet do receptor usando sulfato de condroitina 4 por cento e hialuronato de sódio 3 por cento. Dez (10) pacientes apresentavam ceratocone avançado, 3 tinham leucoma por herpes simples eem 1 havia irregularidade corneana pós-ceratotomia radial. O acompanhamento pós-operatório variou de 12 a 48 meses (média 24 ñ10,5 meses). Resultados: Após a retirada de todas as suturas a média do equivalente esférico no último exame oftalmológico foi de -2,0 ñ 3,6 dioptrias (D) (-10,3 D a +4,74 D). O astigmatismo final variou de -6,0 DC a-0,75 DC com média de -3,3 ñ 1,9 DC. Dos 14 pacientes 12 apresentaram na visita final acuidade visual com correçäo de 20/40 ou melhor. Todos os pacientes ganharam linha de visäo pela tabela de Snellen. Näo houve presença de edema corneano, descompensaçäo endotelial ou rejeiçäo. Nenhuma opacidade ou depósito na interface foi observado. Dois pacientes apresentaram dobras na membrana de Descemet com baixa da acuidade visual. Conclusäo: Apesar das dificuldades técnicas relacionadas à ceratoplastia lamelar e viscodissecçäo da membrana de Descemet, acreditamos que este seja um procedimento de escolha em pacientes cuja populaçäo de células endoteliais esteja preservada. Esta técnica resulta em melhor acuidade visual final quando comparada ao transplante lamelar tradicional e menor reaçäo imunológica quando comparada a ceratoplastia penetrante. Independentemente da qualidade do tecido doador, conseguimos córneas transparentes como resultado, pois o endotélio do receptor foi preservado.