Spherical aberration and contrast sensitivity in eyes implanted with aspheric and spherical intraocular lenses: a comparative study.

PURPOSE: To determine whether implantation of an intraocular lens (IOL) with a modified anterior aspheric surface results in reduced spherical aberration and improved contrast sensitivity after cataract surgery. DESIGN: Prospective, comparative, interventional case series. METHODS: In an intraindividual randomized prospective study of 25 patients with bilateral cataract, an IOL with a modified anterior surface (Tecnis Z9001; Advanced Medical Optics, Santa Ana, California, USA; group 1) was compared with biconvex lens with spherical surfaces (ClariFlex; Advanced Medical Optics; group 2). Ocular aberrations for a 5.0-mm pupil and 6.0-mm pupil were measured with Hartmann-Shack aberrometer. Quality of vision was measured by visual acuity and contrast sensitivity under mesopic and photopic conditions. All patients were followed up for three months. RESULTS: No statistically significant difference in postoperative uncorrected and best-corrected distance vision acuity after a follow-up of three months existed between the groups. Postoperative contrast sensitivity testing revealed significant differences between the groups under photopic and mesopic conditions. These differences reached statistical significance under photopic conditions at three spatial frequencies and under mesopic conditions at all spatial frequencies. When analyzing higher-order aberrations, the difference between the groups was statistically significant at the 5.00-mm and 6.00-mm pupil diameters, with the group 1 inducing less higher-order aberration and also less spherical aberration compared with group 2. CONCLUSIONS: Results show the Tecnis Z9001 IOL with a modified anterior aspheric surface induced significantly less higher-order aberration and spherical aberration compared with the ClariFlex IOL. Contrast sensitivity revealed better values under photopic and mesopic conditions with the Tecnis Z9001 IOL.

Ocular aberrations and contrast sensitivity after cataract surgery with AcrySof IQ intraocular lens implantation Clinical comparative study.

PURPOSE: To determine whether implantation of an intraocular lens (IOL) with a modified posterior aspherical surface (AcrySof IQ, Alcon Surgical Laboratories) results in reduced ocular aberrations (spherical aberration) and improved contrast sensitivity after cataract surgery. SETTING: Brasilia Ophthalmologic Hospital, Brasilia, and Sao Geraldo Eye Hospital, Federal University of Minas Gerais, Belo Horizonte, Brazil. METHODS: In an intraindividual randomized prospective study of 25 patients with bilateral cataract, an IOL with a modified posterior surface (AcrySof IQ) was compared with a biconvex IOL with spherical surfaces (AcrySof Natural, Alcon). Ocular aberrations with a 5.0 mm and 6.0 mm pupil were measured with a Hartmann-Shack aberrometer. Quality of vision was measured by visual acuity and contrast sensitivity under mesopic and photopic conditions. All patients were followed for 3 months. RESULTS: There were no statistically significant differences between eyes in postoperative uncorrected and best corrected distance visual acuities after a follow-up of 1 month and 3 months. Postoperatively, there was a statistically significant between-group difference in contrast sensitivity under photopic conditions without glare at 18 cycles per degree (cpd) (P = .04) and under mesopic conditions without glare at all spatial frequencies (3 cpd, 6 cpd, 12 cpd, and 18 cpd; P = .03, P = .009, P = .003, and P = .003, respectively) and with glare at 3 cpd and 6 cpd (P = .001 and P = .02, respectively). The difference in higher-order aberration (HOA) values between groups was statistically significant with a 5.0 mm and 6.0 mm pupil, with the AcrySof IQ IOL inducing less HOA than the AcrySof Natural IOL. Eyes with an AcrySof IQ IOL also had statistically significant less spherical aberration than eyes with an AcrySof Natural IOL with both pupil diameters (P<.001). CONCLUSIONS: The AcrySof IQ IOL with a modified posterior surface induced significantly less HOA and spherical aberration than the AcrySof Natural IOL. Contrast sensitivity was better under mesopic conditions with the AcrySof IQ IOL.

The effect of hinge position and depth plate on the rate of recovery of corneal sensation following LASIK.

PURPOSE: To evaluate and compare the effect of hinge position and flap thickness on recovery rate of corneal sensation after (LASIK). DESIGN: Prospective, randomized clinical study. METHODS: Forty eyes of 40 patients underwent LASIK to correct myopia ranging from -1.00 to -2.50 diopters. Corneal sensitivity was measured preoperatively and each month after surgery until recovery to preoperative level. The nasal-hinged ACS microkeratome (NH) with depth plates of 130 and 160 microm and the superior-hinged Hansatome microkeratome (SH) with depth plates of 160 and 180 microm were used for corneal flap creation. The eyes were divided into four groups according to the hinge position and depth plate (DP): group 1, NH and 130 microm DP; group 2, NH and 160 microm DP; group 3, SH and 160 microm DP; group 4, SH and 180 microm DP. RESULTS: Corneal sensitivity returned to preoperative level after 3.7 (+/- 0.4), 4.4 (+/- 0.6), 5.4 (+/- 0.8), and 5.8 (+/- 0.9) months, respectively, in groups 1, 2, 3, and 4. Statistically significant differences were found between groups 1 and 2, but not between groups 3 and 4. Corneal sensitivity gradually returned to preoperative levels in all groups. Sensitivity of the hinge area was higher than other areas at every time point. CONCLUSIONS: The results suggest that after LASIK, hinge position and flap thickness seem to be important factors in the rate of return of corneal sensitivity. A thin flap with a nasally placed hinge is associated with the most rapid recovery of corneal sensitivity.

Aspectos epidemiológicos e terapêuticos das infecções oculares em serviços de referência / Epidemiology and therapy of ocular infections in eye's hospitals

Introdução: As infecções oculares são um desafio constante na prática oftalmológica diária. Material e Métodos: Foram analisados 155 casos de infecções oculares supostamente bacterianas, atendidos nos serviços do Instituto/Fundação Hilton Rocha, de janeiro de 1996 a dezembro de 1999. Resultados: O quadro clínico predominante foi a conjuntivite (29,6 por cento), seguido pela blefarite (27,09 por cento) e úlcera de córnea (21,29 por cento). Nos casos de cultura positiva, os microorganismos mais comumente isolados foram o estafilococos epidermidis (48,12 por cento) e o estafilococos aureus (38,34 por cento). Dentre os agentes patológicos detectados, o estafilococos aureus foi o que apresentou maior resistência aos antibióticos utilizados na prática oftalmológica (41,18 por cento a ofloxacina). Conclusão: A análise laboratorial rigorosa e a escolha criteriosa dos medicamentos, muitas vezes com associação de drogas, são passos fundamentasis para o sucesso nestes casos.