Giuseppe Ferreri

Corneal endothelium evaluation in type I and type II diabetes mellitus.

Background: The purpose of this study is to evaluate the corneal endothelium in type I and type II diabetic patients. Methods: Seventy-five diabetics divided into type I and type II groups and 62 healthy volunteers took part in the study. The mean endothelial cell density and morphology, and the central corneal thickness were evaluated and statistical analysis was done. Results: All evaluated parameters were found to be significantly different in both diabetic groups with reduction of the mean cell density of 5% in type II and of 11% in type I diabetes with respect to the normal age-matched control group. Important alterations of endothelial morphology were observed. The central corneal pachymetry was significantly higher in diabetics, with p < 0.01 in the type I group and p < 0.05 in the type II group. Conclusion: It is concluded that corneal endothelium in diabetices should still be considered as a tissue under continuous metabolic stress with consequent high vulnerability, especially in case of any external insult such as a surgical procedure.

Impression cytology of the conjunctival epithelium in patients with vernal conjunctivitis.

The alterations in the conjunctival epithelium during the course of vernal conjunctivitis were examined by conjunctival impression cytology. The study was carried out on 53 patients with vernal conjunctivitis and 20 normal subjects as control. The results of impression cytology demonstrated that all cytological parameters were significantly modified in vernal conjunctivitis patients; the earliest alterations were found in the distribution of goblet cells, in the intercellular junctions, in the chromatin morphology and in the degree of keratinisation. The morphometric comparison showed that in vernal conjunctivitis patients the mean number of goblet cells per field was significantly higher than in controls. Moreover the mean diameter of goblet cells was smaller in patients than in controls. Impression cytology can, therefore, be a simple, non-invasive and cheap method for the study of the ocular surface in vernal conjunctivitis.

The effects of the topical administration of non-steroidal anti-inflammatory drugs on corneal epithelium and corneal sensitivity in normal subjects

Purpose To study the changes in the corneal epithelium and corneal sensitivity of healthy subjects after the topical administration of non-steroidal anti-inflammatory drugs (NSAIDs; diclofenac, indomethacin, flurbiprofen and ketorolac) frequently used in ocular therapy.Methods A double-masked parallel clinical study was undertaken on 90 subjects (45 men, 45 women; Caucasian; age 21–46 years, mean SD 27.1 5 years). The subjects were divided into six groups: group 1 was treated with placebo, group 2 with 0.1% diclofenac, group 3 with 0.1% indomethacin, group 4 with 0.03% flurbiprofen, group 5 with 0.5% ketorolac and group 6 with 0.4% oxybuprocaine. One eye was randomly treated with the study drug and the fellow eye was treated with placebo. The medications were instilled four times, at 5 min intervals. Assessment of the corneal epithelium was carried out by vital fluorescein stain before instillation and 5, 15, 30 and 60 min after instillation of the last drop. Subjective burning sensation was assessed by asking participants to rate burning on a scale from 0 (none) to 3 (severe). After 1 week, assessment of corneal sensitivity was carried out by the Cochet-Bonnet method, repeating the above scheme of instillation and measurement times.Results None of the study drugs, with the exception of oxybuprocaine, produced evident epithelial damage. All the drugs caused a mean burning sensation greater than the placebo. The diclofenac-treated group showed a statistically significant decrease in corneal sensitivity (p 0.001) at the measurement carried out 15 min after instillation of the last drop and lasting up to the end of the study, when the corneal anaesthesia was similar to that induced by the topical anaesthetic treatment. No significant changes weredemonstrated for the other NSAIDs when compared either with the placebo-treated eyes or with the fellow eyes.Conclusions Despite a similar mechanism of action and analgesic activity to the other NSAIDs tested, diclofenac was able to induce a reduction in corneal sensitivity. More studies are needed to determine the mechanism of action responsible for this effect.

Morphological changes of the conjunctival epithelium in contact lens wearers evaluated by impression cytology

Purpose Conjunctival changes induced by rigid, gas-permeable and soft contact lenses (CL) were investigated using impression cytology. A scoring system based on seven parameters (specimen cellularity, cell-to-cell contacts, nucleus/cytoplasm ratio, chromatin, goblet cell distribution, keratinisation, inflammatory cells) was used to evaluate the morphological results.Methods One hundred and seventy-two CL-wearing eyes and 40 control eyes were examined. The population was divided into three groups: group 1, control eyes; group 2, asymptomatic CL-wearing eyes; group 3, CL-wearing eyes with intolerance problems. Impression cytology was carried out and all specimens were evaluated according to a scoring system.Results Group 1 specimens always showed normal features in the conjunctival epithelium. In group 2, rigid and gas-permeable lenses produced greater changes in conjunctival morphology than soft lenses, especially as regards cellularity, nucleus/ cytoplasm ratio, goblet cell distribution and total score. On the contrary, in group 3 wearers of soft lenses showed higher partial and total scores than wearers of gas-permeable and rigid lenses.Conclusions In asymptomatic CL wearers conjunctival morphology was better preserved in wearers of soft lenses. In patients with intolerance problems, wearers of soft lenses showed the worst cytological features. Impression cytology, evaluated with this scoring system, can be used to demonstrate epithelial damage occurring in CL-wearing patients.

Prospective, Multicenter Demographic and Epidemiological Study on Vernal Keratoconjunctivitis: A Glimpse of Ocular Surface in Italian Population

Purpose: To evaluate the frequency and epidemiological features of vernal keratoconjunctivitis (VKC) in Italy. Methods: a specific electronic clinical chart for vernal keratoconjunctivitis was created to standardize: 1) medical history; 2) diagnostic criteria; 3) signs and symptoms; and 4) treatments. This study involved 6 Italian referral centers for ocular surface diseases: between March 2005 and March 2006, all referred patients were included, clinical data collected and statistically examined. Results: The mean age of the vernal keratoconjunctivitis population (n = 156) was 13.8 ± 8.8 with 64.1% of subjects under 14 years of age and a male/female ratio of 3.5:1. Among VKC patients, 48.7% showed associated systemic allergic diseases. Only 32.1% of patients were positive for RAST and/or prick test. The limbal form (53.8%) was the most frequent subtype of vernal keratoconjunctivitis. Approximately 9% of patients showed a severe form of vernal keratoconjunctivitis. At the first visit patients were treated with: multiple action or mast cell stabilizer eye drops (58.1% and 41.3% of cases, respectively), topical corticosteroids alone (0.6%) or in association (26.8% of cases). All patients used topical steroids at least once in the studied year. Systemic antihistamine therapy was used by 25.6% of patients. In this cohort, 32.7% of patients required two or more examinations per year for exacerbations of their symptoms. Conclusion: Vernal keratoconjunctivitis is a severe ocular condition that mainly affects young males. Vernal keratoconjunctivitis is characterized by different clinical features and therapeutic responses, suggesting the need for a standardized therapeutic approach on the basis of a grading of disease severity.

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.

Age and Metabolic Control Influence Lens Opacity in Type I, Insulin-Dependent Diabetic Patients

Cataract is a frequent ocular complication in diabetic patients, but few data are available concerning early modifications occurring in the lens of these patients and their relationship with metabolic control and other clinical parameters. We measured lens opacity in 73 type I, insulin-dependent diabetic patients aging 50 years or less and without clinical evidence of cataract, and in 46 healthy volunteers of similar age. We used a quick, simple, and reliable instrument, the Lensmeter 701, which is based on a back-light scattering quantification system and is able to quantify lens transparency along the nuclear axis. Mean lens opacity was significantly (p = 0.0001) higher in diabetic patients than in the control group, and multiple regression analysis showed that it correlated with age (p = 0.0001) and HbA1c levels (p = 0.009). Moreover in the younger group of patients (age < or =20 years) the only observed correlation was that with Hba1c (p = 0.03), whereas in the older ones (age 21-30 and >30 years) lens opacity correlated with age (p = 0.02 and p = 0.01). These data indicate that early opacifications of the lens occur in type I, insulin-dependent diabetic patients and are influenced by the degree of the metabolic control in the younger ones, whereas the well-known role of aging on lens transparency became prevalent in the older patients. Only longitudinal studies, however, can demonstrate whether these alterations represent any early stage of cataractagenesis and the role of good metabolic control in preventing this ocular complication.

Extra-muscle involvement in dystrophinopathies: an electroretinography and evoked potential study

Dystrophin is present in various tissues other than skeletal and cardiac muscles, including the central nervous system (CNS) and the outer plexiform layer of the retina. Therefore lack of dystrophin might be related to mental retardation or to changes in electrophysiological tests exploring retina and CNS. We performed electroretinography, VEPs, BAEPs, SEPs and MEPs in 18 patients with Duchenne muscular dystrophy (DMD), 18 with Becker muscular dystrophy (BMD) and 12 obligate carriers. We observed a marked reduction of the b-wave amplitude in the scotopic ERG, mainly in DMD patients. Oscillatory potentials were altered in all groups, even in carriers, suggesting that dystrophin may be also involved in retinal circulation. VEPs changes confirmed the role of dystrophin in visual function. The other evoked potentials were altered only in a small percentage of subjects but changes of different tests did not overlap in individual subjects. Neurophysiological abnormalities did not correlate with type, site and size of alteration in the dystrophin gene.

The eye in cystic fibrosis.

Purpose To investigate modifications of ocular surface and lens transparency in patients with cystic fibrosis in relation to the stage of digestive insufficiency. Methods Forty consecutive patients with cystic fibrosis and 24 age- and sex-matched healthy volunteers were examined. The tear tests (Schirmers basic test, tear film break-up time) and conjunctival exfoliative cytology (CC) were used to study the ocular surface. The lens transparency was measured with the Opacity Lens Meter 701 (OLM 701, Interzeag AG, Switzerland). Digestive insufficiency was evaluated by the steatocrit method. Results Significant changes in conjunctival cytology and lens opacity, and abnormal tear tests were detected in CF patients; the alterations were more pronunced in patients with severe digestive insufficiency. Conclusions Cystic fibrosis patients present ocular surface abnormalities and lens transparency modifications and their severity is related to the digestive insufficiency. Simple, rapid and non-invasive tear tests and cytological procedures might be used as additional tests for assessing the severity of cystic fibrosis.

Experimental and clinical investigation of efficiency and ablation profiles of new solid-state deep-ultraviolet laser for vision correction

Purpose: To investigate the efficiency and ablation profiles of a newly developed, all‐solid‐state laser platform. Setting: Experimental investigations performed at Katana Technologies GmbH, Kleinmachnow, Germany, and clinical study, at the Ophthalmology Clinic, University of Messina, Messina, Italy. Methods: Experimental studies were performed on poly(methyl methacrylate) (PMMA) and in porcine eyes using an all‐solid‐state, Q‐switched, frequency‐shifted laser (LaserSoft, Katana Technologies GmbH) with a Gaussian spot with a diameter of 0.2 mm in the target plane, a peak fluence of 350 mJ/cm2, and a repetition rate of 1 kHz. The ablation profiles were determined using a profile meter (MicroProf, Fries Research and Technology GmbH), corneal topography was analyzed with a TMS 2N (Tomey Inc.), and corneal thickness was measured with an ultrasound pachymeter (DGH Technology). In the clinical study, 9 human eyes were treated with photorefractive keratectomy. The mean outcome measures were uncorrected visual acuity (UCVA), best spectacle‐corrected visual acuity (BSCVA), corneal topography, and corneal transparency. The follow‐up was 1 month for all eyes and 3 months for 4 eyes. Safety, efficacy, and predictability were evaluated. Results: Smooth profiles were found in the PMMA and the porcine eyes. The topographic maps showed central steepening after the hyperopic ablation and slight central flattening of the surface after the myopic treatment. No eye lost lines of BSCVA; the UCVA improved in all eyes. All eyes were within ±1.00 diopter (D) of emmetropia, and 89% were within ±0.50 D. Conclusion: The efficacy of the ablation was good, with the profile meter results confirmed by the topographic measurements.