Human corneal thickness and its impact on intraocular pressure measures: a review and meta-analysis approach.

The reactive oxygen species (ROS) form under normal physiological conditions and may have both beneficial and harmful role. We search the literature and current knowledge in the aspect of ROS participation in the pathogenesis of anterior and posterior eye segment diseases in adults. ROS take part in the pathogenesis of keratoconus, Fuchs endothelial corneal dystrophy, and granular corneal dystrophy type 2, stimulating apoptosis of corneal cells. ROS play a role in the pathogenesis of glaucoma stimulating apoptotic and inflammatory pathways on the level of the trabecular meshwork and promoting retinal ganglion cells apoptosis and glial dysfunction in the posterior eye segment. ROS play a role in the pathogenesis of Leber's hereditary optic neuropathy and traumatic optic neuropathy. ROS induce apoptosis of human lens epithelial cells. ROS promote apoptosis of vascular and neuronal cells and stimulate inflammation and pathological angiogenesis in the course of diabetic retinopathy. ROS are associated with the pathophysiological parainflammation and autophagy process in the course of the age-related macular degeneration.

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The Role of the Reactive Oxygen Species and Oxidative Stress in the Pathomechanism of the Age-Related Ocular Diseases and Other Pathologies of the Anterior and Posterior Eye Segments in Adults

Familial adenomatous polyposis (FAP) is an autosomal dominant inherited disease characterized by the presence of adenomatous polyps in the colon and rectum, with inevitable development of colorectal cancer if left untreated. FAP is caused by germline mutations in the adenomatous polyposis coli (APC) gene. Somatic mutations in the APC gene are an early event in colorectal tumorigenesis, and can be detected in the majority of colorectal tumours. The APC gene encodes a large protein with multiple cellular functions and interactions, including roles in signal transduction in the wnt-signalling pathway, mediation of intercellular adhesion, stabilization of the cytoskeleton and possibly regulation of the cell cycle and apoptosis. The fact that APC is an integral part of so many different pathways makes it an ideal target for mutation in carcinogenesis. This review deals with our understanding to date of how mutations in the APC gene translate into changes at the protein level, which in turn contribute to the role of APC in tumorigenesis.

The ABC of APC

Familial Adenomatous Polyposis

Comparison of Conjunctival Autografts, Amniotic Membrane Grafts, and Primary Closure for Pterygium Excision

Purpose To assess the Artisan intraocular lens to correct myopia in phakic eyes. Setting European multicenter study sponsored by Ophtec BV, Groningen, The Netherlands. Methods In this prospective multicenter clinical study, the Artisan lens was implanted in 518 eyes between September 1991 and October 1999. The power of the lenses ranged from −5.0 to −20.0 diopters (D). Follow-up examinations were performed at 6 months and 1, 2, and 3 years. Follow-up ranged from 6 months (n = 454) to 3 years (n = 249). The preoperative uncorrected visual acuity (UCVA) was not recorded but was estimated to be worse than 0.1. The preoperative mean best spectacle-corrected visual acuity (BSCVA) was 0.67 ± 0.26 (SD). Endothelial cell counts were done at 6 months and 1, 2, and 3 years in a subgroup of 129 eyes. Results A UCVA of 20/40 or better was observed in 76.8% of eyes regardless of the postoperative goal. A BSCVA of 20/40 or better was observed in 93.9% of eyes and remained stable throughout the follow-up. Of the eyes with extremely high myopia (>−15.0 D), 63.3% gained 2 or more lines of BSCVA; of those with moderate myopia (−5.0 to −10.0 D), 23.5% gained 2 or more lines. The mean endothelial cell density change was 4.8% at 6 months, 2.4% at 1 year, 1.7% at 2 years, and 0.7% at 3 years. The incidence of persistent adverse events at 3 years was relatively low. Secondary surgical interventions included repositioning of the lens because of poor initial placement and lens exchange because of preoperative power calculation errors. Glare and halo effects during night driving were noted and were related to large pupils in young patients. Conclusion The Artisan lens is a safe, stable, efficacious, and predictable method to correct −5.0 to −20.0 D of myopia. This study suggests that the corneal endothelial cell loss is stabilized to the physiologically normal level after 3 years.

Multicenter study of the Artisan phakic intraocular lens

Visual performance with multifocal intraocular lenses: Mesopic contrast sensitivity under distance and near conditions

Purpose: To study quantitative and morphometric endothelial changes in phakic eyes implanted with the Worst iris-claw lens to correct high myopia. Setting: Department of Ophthalmology, University Hospital “La Fe”, Valencia, Spain. Material and Methods: This retrospective study involved 111 phakic eyes (73 patients) implanted with the Worst iris-claw lens. Noncontact specular microscopy and computer-assisted analysis was performed preoperatively and 6 months and 1, 2, 3, and 4 years postoperatively. Results: The mean cell loss was 3.85% at 6 months, 6.59% at 1 year, 9.22% at 2 years, 11.68% at 3 years, and 13.42% at 4 years. At 2 years, the hexagonality and coefficient variation in cell size were close to the preoperative levels. No major complications were seen; early postoperative corneal touch required intraocular lens (IOL) removal in 1 case (0.9%). Four eyes (3.6%) needed a reoperation because of poor IOL fixation (2 eyes), traumatic subluxation of the IOL (1 eye), and miscalculation of the IOL power (1 eye). Conclusions: Although there was a slight, progressive cell loss after IOL implantation, the morphometric changes recovered and were close to the preoperative levels. This suggests that endothelial damage occurred primarily during the surgical procedure.

Endothelial study of iris-claw phakic lens: Four year follow-up

PURPOSE The purpose of this study was to establish the alterations of oxidative stress-related markers in keratoconus (KC) corneas. METHODS A total of 6 healthy and 11 ectatic corneas (7 KC and 4 post-LASIK) were studied. Different oxidative stress-related markers were determined to assess their implication in the KC pathophysiology. Total antioxidant capacity and total nitrites present in the samples were assayed. Furthermore, lipid peroxidation products and the glutathione contents were determined, together with 4-hydroxynonenal (4-HNE) immunohistochemistry, to establish the relationship between KC and oxidative stress. RESULTS The antioxidant capacity and glutathione content in KC corneas were decreased significantly when compared with healthy corneas. Moreover, the total nitrites and lipid peroxidation were significantly elevated in the corneas with KC when compared with the controls. There was a statistically significant difference in the amount of HNE-positive cells in KC corneas when compared with healthy corneas by immunohistochemistry. Post-LASIK ectatic corneas and KC corneas showed similar results. CONCLUSIONS The increased levels of oxidative stress markers and the decreased antioxidant capacity and antioxidant defenses in KC corneas, as well as in the post-LASIK ectatic corneas, indicate that oxidative stress might be involved in the development of this disease and may provide new insights for its prevention and treatment in the future.

Oxidative stress in keratoconus

Purpose To analyze the image quality with a refractive and 2 hybrid refractive–diffractive multifocal intraocular lenses (IOLs) in vitro to determine the IOL modulation transfer function (MTF) following the EN-ISO international standard for distance and near vision and to study the IOLs' behavior with different pupil sizes. Setting Fundacion Oftalmologica del Mediterraneo, Valencia, Spain. Methods This study evaluated 4 IOLs: the hybrid refractive–diffractive AcrySof ReSTOR SN60D3 (Alcon) and Tecnis ZM900 (AMO), the refractive ReZoom NXG (AMO), and the monofocal AcrySof SN60WF (Alcon). The MTF was calculated from the cross-line spread function recorded with the OPAL Vector System (Image Science Ltd.) using fast Fourier transform techniques. The artificial eye model simulated in vivo conditions of the anterior chamber and included an artificial cornea and physiological solution, in which the IOLs were positioned. The pupil sizes varied between 2.0 mm and 5.0 mm in steps of 0.5 mm. Results For distance vision and small pupils (2.0 to 3.5 mm), the refractive IOL provided better image quality than the 2 hybrid IOLs. When the pupil was larger, the distance vision was similar with all IOLs. The 2 hybrid IOLs gave better image quality than the refractive IOL for near vision with any pupil size. With the refractive IOL and pupils smaller than 3.5 mm, near focusing did not occur, resulting in poor image quality. Of the hybrid IOLs, the AcrySof ReSTOR SN60D3 provided better distance image quality and the Tecnis ZM900 provided better near image quality. Conclusions The refractive IOL gave better image quality than the hybrid IOLs at distance and with small pupils. With pupils larger than 3.5 mm, the quality was similar. Hybrid IOLs gave significantly better image quality for near vision with all pupil sizes. AcrySof ReSTOR SN60D3 IOLs give better distance vision than Tecnis ZM900 IOLs; the latter gave better near vision. The reference monofocal IOL provided better distance images than any multifocal IOL with all pupil sizes.

José L. Menezo

Papers

Multicenter study of the Artisan phakic intraocular lens

Visual performance with multifocal intraocular lenses: Mesopic contrast sensitivity under distance and near conditions

Endothelial study of iris-claw phakic lens: Four year follow-up

Oxidative stress in keratoconus

Image quality with multifocal intraocular lenses and the effect of pupil size Comparison of refractive and hybrid refractive-diffractive designs