[Role of optical coherence tomography in unilateral amblyopia]. / Apport de la tomographie en cohérence optique dans l'amblyopie unilatérale.

PURPOSE: To compare the macular and papillary parameters on optical coherence tomography (OCT) between the amblyopic eye and the healthy eye in subjects with unilateral strabismic or anisometropic amblyopia. PATIENTS AND METHODS: This is a cross-sectional and comparative study carried out over two years, from April 1, 2019, to March 31, 2021. We included patients aged over 5years, followed for unilateral amblyopia, free of any neurological and/or ocular pathology. The evaluation of the macular and papillary parameters in the amblyopic and healthy eyes was performed with Swept-Source Optical Coherence Tomography (OCT-SS). The parameters were compared according to age group and type of amblyopia. RESULTS: We collected 50 patients, 29 children, and 21 adults, with a mean age of 19.8years. Amblyopia was secondary to anisometropia in 40 patients and strabismus in 10 patients. Analysis of macular tomographic parameters found no significant difference between amblyopic eyes and healthy eyes for mean macular thickness (P=0.86), central macular thickness (P=0.86), or mean macular volume (P=0.54). The mean retinal peripapillary fiber thickness (RNFL) was 107.48µm in the amblyopic eye and 103.8µm in the healthy eye, with a statistically significant difference (P<0.001). This significant thickening of the RNFL in amblyopic eyes was present in adults (P<0.001), children (P<0.001), anisometropic (P<0.001), and strabismic amblyopia (P=0.024). Analysis of the other optic nerve head parameters revealed no significant difference between amblyopic eyes and healthy eyes in terms of optic disc surface area (P=0.89), neuro-retinal annulus surface area (P=0.47), vertical (P=0.98) or horizontal (P=0.74) cup to disc ratio. CONCLUSION: Amblyopia is accompanied by thickening of the peripapillary retinal fibers without macular repercussions. However, larger prospective studies are needed to confirm these results.

[Incidence and causes of visual impairment in the district of Mahdia, in east Tunisia: Retrospective study of 1487 cases]. / Incidence et causes de déficiences visuelles au Gouvernorat de Mahdia, à l'est de la Tunisie : étude rétrospective à propos de 1487 cas.

OBJECTIVE: To study socio-demographic characteristics and main causes related to visual impairment (VI) as a function of age bracket and to analyze their trends over time in the district of Mahdia. METHOD: A retrospective review was performed on 1487 cases of visual impairment registered with the social authorities in Mahdia, between 1980 and 2013. The social, demographic, vision exam findings and causes were ascertained and analyzed in an SPSS database. Incidence rates of VI and blindness due to various causes were calculated based on the demographic data from the NSI to estimate the time trends using the general linear regression model and Spearman correlation. RESULTS: Analyses included 1487 participants with a median age of 47 years, 40.6% of cases were aged under 45 years. Children accounted for 11.1% (165 patients), while age was between 16 and 45 years in 29.5% (439 patients), between 46 and 65 years in 31.5% (469 patients) and greater than 65 years in 27.8% (414 patients). The sex-ratio (M/F) was 1.78. Socially, 51% came from rural areas, 62% were illiterate, and 84% were unemployed. We observed blindness in 70% of participants and low vision in 30%. In children, the causes were dominated by congenital cataract and congenital glaucoma, each present in 31 children (18.8%). Between 16 and 45 years, glaucoma and hereditary dystrophies of the retina were found in 62 and 61 patients respectively (14% each). For age between 46 and 65 years, trachoma was responsible for 19.8% of cases of VI, glaucoma in 15.8% and cataract in 15.1%. Beyond 65 years, glaucoma accounted for 30.7% of the causes of VI and cataract 27.8% of cases. Trend analysis shows a significant increase in the incidence rate of visual impairment with an average of 12% per year (P=0.001). The mean age increased by 46% (P=0.003). Trachoma increased by 118% (P<0.0001) between 1980 and 1990, then declined by 42% (P=0.0013) between 1991 and 2013. Incidence of VI significantly increased by 4% for cataract (P=0.001), 23% (P=0.001) for glaucoma and 20% (P=0.02) for diabetic retinopathy, while VI related to refractive errors and AMD showed no significant change. CONCLUSION: Advanced age, lower educational and socio-economic status were associated with bilateral VI. Age related eye problems are the main causes of VI, and their incidence is tending to increase. Public health policies and procedures should be targeted to risk related populations and age-related diseases in order to control the incidence of visual impairment and avoid its consequences.