Protective effects of trehalose on the corneal epithelial cells.

PURPOSE: Aim of the present work was to evaluate the effects of the trehalose on the corneal epithelium undergoing alcohol delamination. METHODS: Twelve patients undergoing laser subepithelial keratomileusis (LASEK) were consecutively included in the study. The right eyes were pretreated with 3% trehalose eye drops, whilst left eyes were used as control. Epithelial specimens were processed for cells vitality assessment, apoptosis, and light and transmission electron microscopy; a morphometric analysis was performed in both groups. RESULTS: In both trehalose-untreated eyes (TUE) and trehalose-treated eyes (TTE), the percentage of vital cells was similar and no apoptotic cells were observed. In TUE, the corneal epithelium showed superficial cells with reduced microfolds, wing cells with vesicles and dilated intercellular spaces, and dark basal cells with vesicles and wide clefts. In TTE, superficial and wing cells were better preserved, and basal cells were generally clear with intracytoplasmatic vesicles. The morphometric analysis showed statistically significant differences between the two groups: the TTE epithelial height was higher, the basal cells showed larger area and clearer cytoplasm. The distribution of desmosomes and hemidesmosomes was significantly different between the groups. CONCLUSIONS: Trehalose administration better preserved morphological and morphometric features of alcohol-treated corneal epithelium, when compared to controls.

One year outcome of manual alcohol-assisted removal of Salzmann's nodular degeneration.

BACKGROUND: To analyze visual and refractive modifications and corneal topography changes in a patient treated for bilateral advanced Salzmann's nodular degeneration (SND). METHODS: A forty-three-year-old man with bilateral advanced SND underwent manual, alcohol-assisted removal of the altered layer. Visual acuity, refraction, corneal topography and corneal aberrations were examined before and after the treatment after 7 days and 1, 6 and 12 months. RESULTS: The uncorrected visual acuity changed from 0.1 to 1.0 in both eyes. Refraction changed from sphere +3.00 and cylinder +4.50 x 180 degrees in the right eye and sphere +6 and cylinder +4.0 x 170 degrees in the left eye to bilateral emetropia. Corneal topography recovered from an extremely flat profile to a normal shape and it was unvaried during the follow-up period. Main topographic indices, highly altered before the treatment, normalized and were normal at control examinations. The quality of vision improved significantly with reduction of high-order aberrations from RMS of 5,07 microm to 0,66 microm in the right eye and RMS of 4,89 microm to 0,57 microm in the left eye respectively. CONCLUSIONS: Salzmann nodules produce an impressive central corneal flattening with high hyperopic refractive error and significant increment of corneal aberrations. After manual removal of the altered layer, the visual and refractive recovery, corneal topography and aberrometry normalization were immediate and stable during the observational period.

Age-related modifications of corneal sensitivity.

PURPOSE: To evaluate central and peripheral corneal sensitivity (CS) in relation to age. METHODS: Five hundred eyes of 320 healthy subjects (185 males and 135 females) were examined. The age of participants ranged from 20 to 90 years. All subjects were divided into 3 groups according to age. CS was assessed with the Cochet-Bonnet esthesiometer in the central cornea and in 8 peripheral points. The averages were used as the values of central and peripheral CS. RESULTS: In the young population, CS was equal in both examined zones (p > 0.05); although, with respect to the periphery after the fifth decade, it was significantly higher in the centre (p < 0.05). Both central and peripheral sensitivity decreased with age (p < 0.05), and such variations are represented by parabolic curves. No differences were observed between males and females. CONCLUSIONS: The age-related decrement of CS involves at first the corneal periphery and successively spreads toward the central zone. Topographical distribution and age-related modifications should be considered in clinical investigations of CS, especially in patients who underwent any corneal surgical procedure.

Age-related modifications of the corneal endothelium in adults.

PURPOSE: To obtain the topographical distribution of the corneal endothelial cell density, in different age ranges. METHODS: Three hundred eyes of 204 healthy subjects (110 males (M) and 94 females (F)) aged from 20 to 83 years were evaluated. Participants were divided into three groups according to age. First group (120 eyes) comprised patients aged from 20 to 44 years (mean 32.27 +/- 7.5), the second group (110 eyes) comprised patients aged from 45 to 70 years (mean 54.13 +/- 7.1) and the third group (70 eyes), comprised participants older than 70 years (mean 79.28 +/- 5.9). Specular microscopy was performed in the central zone and in four peripheral points. RESULTS: Central and peripheral cell densities decrease with age (p < 0.05). In young adults the endothelial cell density did not show any significant variation in the central area with respect to the periphery (p > 0.05). In older adults the difference between central and peripheral endothelial cell densities showed the significance level of p = 0.05. CONCLUSIONS: Topographical distribution of the corneal endotheliul cell density is maintained lifelong. Age-related changes involve both center and periphery. The higher peripheral decrement observed in the ancient subjects could be considered as a major finding and in elderly a topographical disparity might occur.