[Accuracy of Optical Coherence Tomography versus Ultrasound in pachymetry]. / Fiabilité de la pachymétrie par OCT comparée à la pachymétrie par ultrasons.

PURPOSE: Measuring the central corneal thickness is an important step in the diagnosis and monitoring of glaucoma. Ultrasound pachymetry was the gold standard before the advent of OCT. The purpose of this study is to assess the reliability of OCT pachymetry compared to ultrasound pachymetry in black patients. PATIENTS AND METHODS: Pachymetry was performed as part of a glaucoma work-up. Ultrasonic pachymetry was measured using the Alcon Ocuscan by the same operator and OCT pachymetry using the Topcon 2000 OCT. The Student's t-test was used to compare means with statistical significance of 5%. The Pearson's correlation coefficient (r2) was used to measure correlations. RESULTS: One-hundred thirty-five right eyes and 135 left eyes, corresponding to 270 eyes of 135 patients, were examined. There was a female predominance (59 men/76 women), with a gender ratio of 0.78. The mean age was 42.3±17.3 [8-86] years. In the right eye, the mean OCT pachymetry was 522.4±36.8µ versus 528.2±37.9µ for ultrasonic pachymetry (P=1.00). In the left eye, the mean OCT pachymetry was 522.0±33.8µ versus 524.9±42.5µ for ultrasonic pachymetry (P=1.00). The overall mean OCT pachymetry was 522.2±35.2µ versus 526.5±40.2µ, with a non-significant difference (P=1.00). There was a strong correlation between ultrasonic pachymetry and OCT pachymetry (r2=0.83; P<0.05). On the other hand, there was a very low correlation between pachymetry and age (r2=0.09; P<0.05). Pachymetry decreased by 5µ per 10 years, corresponding to corneal thinning of 0.5µ per year. CONCLUSION: OCT pachymetry can be a reliable alternative to ultrasound pachymetry and could be performed at the same time as the OCT for glaucoma assessment.

[Optic disc features on OCT in glaucomatous and normal black Africans]. / Caractéristiques de la papille chez les sujets glaucomateux et normaux à l'OCT dans une population Noire Africaine.

PURPOSE: To determine the correlations between the size of the optic disc and glaucomatous defects in black Africans. DESIGN: Retrospective observational study. METHODS: The study was conducted over a two-year period from November 2014 to October 2016, based on records of black Togolese patients who had undergone optic nerve head (ONH) OCT or ganglion cell complex OCT for assessment of glaucoma. The population was divided into 3 groups (I, II and III) depending on the size of the ONH. The ONH was considered small (Group I) if its size was less than the mean -1 SD, medium (Group II) if its size was within 1 SD of the mean, and large (Group III) if its size was greater than the mean+1 SD. Glaucomatous lesions were qualitatively identified on RNFL and or GCC. The ONH parameters were compared in the 3 groups. The Chi-square test was used to compare the percentages, and the t test to compare the means with statistical significance of 5%. The Pearson correlation coefficient (r2) was used to measure correlations. RESULTS: A total of 586 eyes of 298 patients were examined, 314 glaucomatous eyes and 272 healthy eyes. The mean age was 41.0±15.7 [6; 86] years. There were 159 men vs. 137 women, with a sex ratio of 1.2. The mean surface area of the ONH was 2.80±0.55mm2. Small ONH's (Group I) were defined as a surface area of less than 2.25mm2, medium-sized ONH's (Group II) as an area between 2.25 and 3.35mm2 and large ONH's (Group III) as an area greater than 3.35mm2. Small ONH's represented 14.7%, (86 eyes), medium-sized 68.6% (408 eyes) and large ONH's 16.8% (98 eyes). The mean surface area of the neuroretinal rim, cup, the cup-disc ratio and the RNFL thickness were statistically significant in the 3 groups. Similarly, all these parameters were significant in groups of glaucomatous or non-glaucomatous eyes, except for the surface area of the cup. The RNFL thickness was weakly correlated with the surface area of the ONH (r2=0.39), moderately correlated with the surface area of the neuroretinal rim (r2=0.57). The surface area of the ONH was strongly correlated with the surface area of the cup (r2=0.7). The neuroretinal rim surface area was strongly correlated with the cup-disc ratio (r2=0.66). CONCLUSION: The size of the ONH was correlated with the size of the cup, but it was not correlated to the surface area of the neuroretinal rim or the thickness of the nerve fibers. Analysis of the RNFL and GCC is essential for the diagnosis, especially in the case of large ONH's.

[Severe ametropia in children in Lomé (Togo)]. / Les amétropies fortes chez l'enfant à Lomé (Togo).

AIMS: To determine the features of severe ametropia (refractive errors, including myopia, hyperopia, and astigmatism) in children in general practice in Lomé. PATIENTS AND METHODS: We conducted a retrospective study based on records of patients aged 5-16 years seen in a private clinic in Lomé from 1 January, 2001, to 31 December, 2010. We analyzed subjective refraction after automated refraction or retinoscopy. RESULTS: Among 1303 cases of ametropia in children, 58 cases were severe, for a frequency of 4.5%. The mean age of these patients was 12.7 years. The sex ratio (M/F) was 0.7. Among these severe cases, astigmatism was most frequent, accounting for 46.6%, followed by myopia (27.6%) and hyperopia (25.6%). Among children with hyperopia, 80% were assessed at +3.50 D to +6.50 D and 20% from +6.75 D to +9.50 D; among those with myopia, 75% were assessed at -6D to -9.50 D and 25% from -10 D to -14 D. Bilateral amblyopia was found in 9 cases for a frequency of 0.45%. The amblyopia was caused by astigmatism in 1 case, hyperopia in 4 cases, and by myopia in 4 cases. CONCLUSION: The relative frequency of severe ametropia underlines the importance of a routine ophthalmology examination for children starting school.