Medical hypothesis discovery and innovation in ophthalmology

Chalazion is a chronic, localized lipogranulomatous inflammation of the sebaceous glands of the lids. Chalazion occurs often secondary to blockage of the sebaceous gland ducts. Some studies have reported vitamin A deficiency as a risk factor for chalazion. In this study, we determined the serum levels of vitamin A in patients with chalazion. The study involved a total of 107 subjects (52 patients with chalazion and 55 control subjects). The study was conducted at the Ophthalmology Clinics of Imam Khomeini Hospital, Ahwaz Jundishapur University of Medical Sciences, Ahwaz, Iran between September 2014 and February 2015. The subjects were divided into three groups according to age: 7–12 years old, 13–19 years old, and >19 years old. Patients were further divided into four subgroups based on the type of chalazion: single, multiple, primary, and recurrent. Blood samples were collected and the serum was tested for levels of vitamin A using high-performance liquid chromatography (HPLC). The average serum vitamin A levels in patients with chalazion in the age groups of 7–12 and 13–19 years were significantly lower than in their control counterparts. Serum vitamin A levels in patients with recurrent, multiple chalazia were significantly lower than in patients with primary, multiple chalazia (P = 0.026) and patients with a recurrent, single chalazion (P = 0.029). In conclusion, chalazion could be one of the ocular presentations of vitamin A deficiency. This information could be useful in the early diagnosis and treatment of vitamin A deficiency, which could prevent further complications, such as xerosis and nyctalopia. 

The aim of this study was to compare the effect of intravitreal diclofenac, a non-steroidal anti-inflammatory drug (NSAID), with that of bevacizumab, a well-known anti-vascular endothelial growth factor (VEGF) drug, in the treatment of diabetic macular edema (DME). Diclofenac was chosen in this study because it has both features of NSAIDs and corticosteroids by inhibiting the cyclooxygenase (COX) and lipoxygenase pathways, respectively. In this non-randomized comparative interventional case series, 64 eyes from 32 patients with bilateral naïve DME were selected and every eye was randomly assigned to intravitreal injection of bevacizumab (IVB) or diclofenac (IVD). After exclusion of some patients because of short follow-up duration or less than two intravitreal injections, finally, 52 eyes from 26 patients were analyzed. Of those, 26 eyes received 500 µg/0.1 mL IVD and 26 eyes received 1.25 mg IVB. After 6 months of follow-up, the results indicated that visual acuity was significantly improved from 0.50 ± 0.13 in IVB and 0.52 ± 0.12 LogMAR in IVD at baseline to 0.2 ± 0.1 and 0.29 ± 0.07, respectively. Central macular thickness (CMT) and macular volume were measured based on spectral-domain optical coherence tomography (OCT) at month 1, 3, and 6. Both groups showed a significant reduction in CMT and macular volume from baseline but there was no significant difference between the IVB and IVD groups. Interestingly, IVD, but not IVB, decreased intraocular pressure (IOP), which is a desirable effect. There was no serious complication due to injections. This study sheds light into the long-term effects of NSAIDs and may support the idea that inflammation suppression by NSAIDs may have the same results as anti-VEGF administration. 

Patients with proliferative diabetic retinopathy (PDR) who are refractory to complete panretinal photocoagulation (PRP) have a high risk of severe vision loss. The aim of this study was to evaluate the effectiveness of single-dose intravitreal bevacizumab (IVB) after complete PRP in patients with refractory PDR. Patients with retinal neovascularization (NV) secondary to diabetes mellitus and refractory to complete PRP were enrolled in this study. All patients received a single dose of 1.25 mg IVB at 3 months after completing the PRP. Patients underwent complete ophthalmic evaluation and fluorescein angiography (FA) at baseline and 1 month after injection. The main outcome measure was a reduction in the areas of leakage (mm2) on FA. All patients were evaluated at baseline and on every visit at 1 day, 1 week, and 1 month after the injection. A total of 21 consecutive patients (32 eyes) with PDR completed this study. Thirteen (61.9%) patients were female. The mean ± standard deviation (SD) age was 64.1 ± 5.6 years. Complete and partial response of angiographic leakage of NV was noted in 7 (21.9%) and 18 (56.2%) of 32 eyes after a single IVB injection, respectively. No satisfactory response of retinal NV was observed in 7 eyes (21.9%) at 1 month after the injection. There was a significant difference in age between response groups (partial and complete; 61.9 ± 4.4 years) versus the no-satisfactory response group (67.7 ± 5.9 years) (P = 0.007). No significant ocular or systemic adverse events were observed. A single-dose of IVB could be associated with a satisfactory response of retinal NV, secondary to PDR, in patients who are refractory to complete PRP. 

The main purpose of this study was to assess the differences in the peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell-inner plexiform layer (GCIPL) thicknesses between subjects with megalopapilla (MP) and those with large (physiological) cup discs (LCD) measured by spectral-domain optical coherence tomography. The secondary purpose was to determine whether pRNFL and GCIPL thicknesses increase with the optic nerve head (ONH) area. This cross-sectional study included 184 eyes (92 eyes with MP and 92 eyes with LCD). The subjects with LCD were used as sex-and-age-matched controls. All subjects were imaged using the Cirrus HD-OCT system. Macula and pRNFL thickness maps were obtained for all subjects. The inferior quadrant pRNFL thickness was higher in the MP group than in the LCD group (P < 0.05). There were no differences in the GCIPL thickness between the two groups. A positive correlation was found between average, superior, and inferior quadrant pRNFL thicknesses and the ONH area (P < 0.05). The slope of the correlation curve was higher for the inferior quadrant. No correlation was found between the GCIPL thickness and the ONH area. In comparison to patients with LCD, the inferior quadrant pRNFL thickness of patients with MP was higher. As the ONH area increased, the average, superior, and inferior quadrant pRNFL thicknesses also increased. In patients with MP, the assessment of a glaucomatous lesion based on pRNFL thickness measurements may not be reliable. It is recommended that in these patients, the evaluation of glaucomatous damage be based on the GCIPL thickness map analysis rather than on the pRNFL thickness. 

This study aimed to assess the possible relationship of body mass index (BMI) and blood pressure (BP) with corneal biomechanical parameters in healthy subjects. The study included 88 eyes of 88 healthy subjects aged 20–40 years. After a thorough medical history, a digital sphygmomanometer was used to measure the systolic blood pressure (SBP) and diastolic blood pressure (DBP). In addition, several hematological and biochemical parameters were determined to assess general health. Before the ophthalmic examination, the body height and weight were measured; then, the BMI was calculated. Finally, after comprehensive ophthalmic examination, all cases were evaluated with Pentacam (Oculus) in order to rule out corneal ectasia; then, the corneal biomechanical parameters of all individuals were measured using the Scheimpflug-based Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany). If the measurements of the hematological and biochemical parameters were within normal range, the results of the Corvis ST, BMI, and BP were included in the analysis carried out with SPSS software. The mean (± standard deviation [SD]) BMI, SBP, DBP, intraocular pressure (IOP), central corneal thickness (CCT), deformation amplitude, radius, and peak distance was 27.24 ± 4.80 kg/m2, 116.47 ± 11.21 mmHg, 80.51 ± 5.68 mmHg, 15.10 ± 1.70 mmHg, 533.10 ± 30.97 ï­m, 1.03 ± 0.11 mm, 7.51 ± 0.86 mm, and 5.03 ± 0.30 mm, respectively. According to the World Health Organization’s classification of BMI, the results showed no significant difference in IOP, CCT, peak distance, radius, and deformation amplitude between different BMI subcategories (all P > 0.05). The results of the Corvis ST showed that corneal biomechanical parameters had no significant correlation with BMI, SBP, and DBP in three subgroups of BMI and all participants (all P > 0.05) but the results showed a positive correlation between CCT and IOP (P < 0.001, r = 0.504) in all participants. CCT and IOP had no correlation with BMI, SBP, and DBP (all P > 0.05). This study showed that BMI and BP had no correlation with corneal biomechanical parameters in healthy subjects using the Corvis ST. Our results can be used in clinical practice. 

This study aimed to compare second-generation frequency-doubling technology (FDT) perimetry with standard automated perimetry (SAP) in mild glaucoma. Forty-seven eyes of 47 participants who had mild visual field defect by SAP were included in this study. All participants were examined using SITA 24-2 (SITA-SAP) and matrix 24-2 (Matrix-FDT). The correlations of global indices and the number of defects on pattern deviation (PD) plots were determined. Agreement between two sets regarding the stage of visual field damage was assessed. Pearson’s correlation, intra-cluster comparison, paired t-test, and 95% limit of agreement were calculated using SPSS 24.0. The level of significance was set at P < 0.05. Although there was no significant difference between global indices, the agreement between the two devices regarding the global indices was weak (the limit of agreement for mean deviation was -6.08 to 6.08 and that for pattern standard deviation was -4.42 to 3.42). The agreement between SITA-SAP and Matrix-FDT regarding the Glaucoma Hemifield Test (GHT) and the number of defective points in each quadrant and staging of the visual field damage was also weak. Because the correlation between SITA-SAP and Matrix-FDT regarding global indices, GHT, number of defective points, and stage of the visual field damage in mild glaucoma is weak, Matrix-FDT cannot be used interchangeably with SITA-SAP in the early stages of glaucoma.