Factors associated with axial length elongation in high myopia in adults

AIM: To investigate the association of axial length (AL) and ocular factors on AL elongation. METHODS: A retrospective chart review of patients who underwent two or more AL examinations for more than two years. Totally 4 groups were divided according to initial AL (<24 mm, 24-26 mm, 26-28 mm, ≥28 mm). Initial fundus photograph was used to find risk factors associated AL elongation. RESULTS: The mean age of the patients was 47.21±7.79y. AL remained almost unchanged in the groups with AL<24 mm and 24≤AL<26 mm. On the contrary, AL increased by 0.011 mm/y in the group with 26≤AL<28 mm and 0.035 mm/y in the group with AL≥28 mm (P<0.001). In high myopia, AL elongation increased in eye with longer AL (r=0.003, P=0.024), female gender (r=0.014, P=0.019), eye with larger peripapillary chorioretinal atrophic area (r=0.002, P=0.019), and smaller vascular arcade angle (r=-0.004, P=0.006). The risk of elongation 0.03 mm/y in high myopia was increased in female gender (P=0.040), and gradually increased in eye with large peripapillary chorioretinal atrophy area (P<0.01). CONCLUSION: AL elongate significantly in the eye with longer AL, female gender, and the eye with larger atrophic area and smaller arcade angle on fundus photography.

Predictors of Visual outcome in Post Fever Retinitis: A Retrospective Analysis

Purpose: To identify the predictors of final visual outcome in cases with post fever retinitis (PFR).Methods : This is a retrospective study of cases with diagnosis of post fever retinitis. Color fundus photograph and optical coherence tomography (OCT) parameters at presentation and final visit were analysed. Various factors at presentation [age, systemic illness, best corrected visual acuity (BCVA), area of retinitis and hard exudates, OCT parameters], at final visit (optic disc pallor, OCT parameters) and the treatment modalities used were correlated with BCVA at final visit.Results : Twenty four eyes of 16 patients with PFR were included in the study. Median BCVA at presentation was 6/60 and at final visit was 6/9. By multiple linear regression after adjusting for other variables, for every 1 unit increase in height of SRF at fovea at presentation, the value of final BCVA decreased by 0.001 unit. For every 1 unit increase in extent of EZ loss and subfoveal deposit height, the value of final BCVA decreased by 0.0001unit and 0.004 unit respectively.Conclusion: Height of SRF at presentation, extent of EZ loss and subfoveal deposit height at final visit were associated with poor final BCVA in PFR.

Detection of Diabetic Retinopathy Using Bichannel Convolutional Neural Network

Deep learning of fundus photograph has emerged as a practical and cost-effective technique for automatic screening and diagnosis of severer diabetic retinopathy (DR). The entropy image of luminance of fundus photograph has been demonstrated to increase the detection performance for referable DR using a convolutional neural network- (CNN-) based system. In this paper, the entropy image computed by using the green component of fundus photograph is proposed. In addition, image enhancement by unsharp masking (UM) is utilized for preprocessing before calculating the entropy images. The bichannel CNN incorporating the features of both the entropy images of the gray level and the green component preprocessed by UM is also proposed to improve the detection performance of referable DR by deep learning.

Contrast and color balance enhancement for non-uniform illumination retinal images

Color retinal images play an important role in supporting a medical diagnosis. However, some retinal images are unsuitable for diagnosis due to the non-uniform illumination. In order to solve this problem, we propose a method for improving non-uniform illumination that can enhance the image quality of a color fundus photograph suitable for reliable visual diagnosis. Firstly, a hidden anatomical structure in dark regions of the retinal images is revealed by improving the image luminosity with gamma correction. Secondly, multi-scale tone manipulation is then used to adjust the image contrast in the lightness channel of L*a*b* color space. Finally, color balance is adjusted by specifying the image brightness based on Hubbard’s specification. The performance of the applied method has been evaluated against the data from the DIARETDB1 dataset. The results obtained show that the proposed algorithm performs well for correcting the non-uniform illumination of color retinal images.

Unilateral visual impairment in a patient undergoing chemotherapy: a case report and clinical findings

Background Visual impairment occurred as an infrequent form of chemotherapeutic toxicity and was often underestimated despite of several reports. We described a case of acute unilateral visual impairment after one cycle of intravenous chemotherapy of a normal dose, aiming at raising attention to chemotherapy-induced ocular toxicity. Case presentation The patient developed a progressive vision loss in the right eye during the chemotherapy. After one cycle of intravenous chemotherapy, her visual acuity decreased by 0.6 in the right eye (VOD = 0.4) compared to the previous value of 1.0 (VOD = 1.0). No evidence of ocular infiltration was observed from the cerebral magnetic resonance imaging (MRI). During her follow-up period, we documented the ophthalmologic examinations including visual acuity, visual field (VF), visual evoked potential (VEP), electroretinogram (ERG), fundus photograph (FP), fundus fluorescein angiography (FFA) and optical coherence tomography (OCT). Ophthalmoscope examination and fundus photograph showed optic disc edema, fuzzy boundary and linear hemorrhages in her right eye. Fundus fluorescein angiography (FFA) revealed capillary underdevelopment at the nasal and superior temporal area of the optic disc in the early phase and capillary fluorescein leakage in the late phase. The result of VEP test suggested the impaired function of the optic nerve. Thus, a diagnosis of nonarteritic anterior ischemic optic neuropathy (NAION) was made by the ophthalmologist according to these results. The patient was prescribed prednisone combined with neuroprotective drugs, which did not work. After the cessation of chemotherapy, her impaired vision gradually recovered. Conclusions This is the first reported case of acute visual impairment in a patient who underwent chemotherapy of a normal dose. It is indicated that while receiving benefits from chemotherapy, cancer patients simultaneously suffer from the risk of vision loss.