Comparison of the long-term effects of high and low altitude on the choroidal thickness

The aim is to evaluate the long-term effects of high and low altitudes on the choroid. This study was a cross-sectional retrospective study. The individuals were divided into two groups according to the altitude where those lived. Those living at low altitude (Sakarya) were included in the low altitude group (LAG), and those living at high altitude (Ağrı) were included in the high altitude group (HAG). Sub-foveal choroidal thicknesses of both groups were compared. Spectral domain optical coherence tomography (SD-OCT) was used to measure the subfoveal choroidal thickness. The average of subfoveal CT in LAG was 270.3±22.2µm, whereas it was 275.1±21.0 µm in HAG. No significant difference in choroid thickness was observed in between the groups ( P= 0.334).The choroid may have the ability to autoregulate and maintain a constant blood flow to the retina under different conditions. [Med-Science 2022; 11(1.000): 335-7

Intraocular pressure measurement over soft contact lens by rebound tonometer:a comparative study

<b>AIM:</b> To evaluate the intraocular pressure (IOP) measurements by Icare rebound tonometer over a contact lens in comparison with Goldmann applanation tonometry (GAT).<b>METHODS:</b> Fifty patients using contact lens were included in this study. One of the eyes of the patients was selected randomly and their IOP were measured by rebound tonometer with and without contact lens (RTCL, RT respectively) and by GAT, as well as their central corneal thickness (CCT) by optical pachymeter. The results of both methods were compared by correlation analysis, general linear method repeated measure and Bland-Altman analysis.<b>RESULTS:</b> Mean IOP values measured by RTCL, RT and GAT were 15.68±3.7, 14.50±3.4 and 14.16±2.8 (<i>P</i>&lt;0.001), respectively. Mean IOP by RTCL was significantly higher than the measurements implemented by RT and GAT (<i>P</i>&lt;0.001), while there was no difference between the measurements by GAT and RT (<i>P</i>=0.629). There was a good level of positive correlation between GAT and RTCL as well as RT (<i>r</i>=0.786 <i>P</i>&lt;0.001, <i>r</i>=0.833 <i>P</i>&lt;0.001, respectively). We have observed that CCT increase did not show any correlation with the differences of the measurements between RTCL and RT (<i>P</i>=0.329), RTCL and GAT (<i>P</i>=0.07) as well as RT and GAT (<i>P</i>=0.189) in linear regression model.<b>CONCLUSION:</b> The average of the measurements over contact lens by rebound tonometer was found to be higher than what was measured by GAT. Although this difference is statistically significant, it may be clinically negligible in the normal population

Ocular surface epithelial thickness changes with SD-OCT in patients treated with oral isotretinoin

AIM: To use in vivo spectral-domain optical coherence tomography(SD-OCT)to investigate ocular surface epithelial thickness changes in patients treated with oral isotretinoin.METHODS: A total of 64 eyes of 64 acne vulgaris patients were enrolled into two group: thirty-two patients received 0.5 mg/kg isotretinoin daily(Group A), and the other 32 patients received 0.8 mg/kg daily(Group B). The central corneal thickness(CCT), central corneal epithelium thickness(CCET), central corneal epithelium basal membrane thickness(CCEBMT), non-epithelial central corneal thickness(NECCT)and bulbar conjunctival epithelium thickness(BCET)were evaluated using SD-OCT at baseline, at the 45th day, at the fourth month of treatment and at the first month after the end of treatment. RESULTS: There were 44 females(68.75%)and 20 males(31.25%)with a mean age of 21.68±3.75y. In both groups, CCET, CCT and BCET were significantly thinner at the 45th day, at the fourth month of the treatment and at the first month after the end of treatment as compared with baseline. CCEBMT decreased significantly at the 45th day and at the fourth month of treatment, but there was no difference between the baseline and the last visit. There were no significant difference in NECCT during and after treatment as compared with the baseline.CONCLUSION:Ocular surface epithelial thickness decreased in patients treated with oral isotretinoin, whereas NECCT was not affected. The decreasing corneal thickness in patients treated with isotretinon is mainly due to epithelial thinning. After a one-month cessation of isotretinoin treatment, CCEBMT returned to the baseline value, and ocular surface epithelial thickness increased