Medical hypothesis discovery and innovation in ophthalmology

Background: To report the posterior segment (uvea and retinal) manifestations and imaging characteristics of eyes of patients with and after coronavirus disease 2019 (COVID-19).
Methods: We searched the PubMed/MEDLINE database to identify relevant articles using the following search terms: COVID-19, SARS-CoV-2, retina, uvea, optic nerve, retinal findings, posterior segment manifestations, and endophthalmitis. Articles published from December 1, 2019, to May 30, 2021, and indexed in PubMed/MEDLINE were screened.
Results: For the purpose of this review, we included clinical features of 26 case reports and 8 case series. The posterior segment manifestations reported included cotton wool spots, retinal hemorrhages, central serous retinopathy, papillophlebitis, optic neuritis, panuveitis, multifocal retinitis, necrotizing retinitis, central retinal artery/vein occlusion, and Purtschner like retinopathy. In this review, we have also included optical coherence tomography angiography (OCTA) features that have been described in COVID-19 patients with pneumonia.
Conclusions: COVID-19 patients can experience uveo-retinal manifestations even after recovery. These patients, even if asymptomatic for eye symptoms, should undergo an eye evaluation to rule out posterior segment involvement. OCTA performed in these patients revealed microvascular changes in the superficial and deep retinal plexuses. Some of these patients may require anticoagulant or antiplatelet therapy.

Background: Refractive amblyopia is the most common cause of amblyopia in the Gaza Strip. However, the pattern of this condition has not yet been studied in this region. This study aimed to determine the pattern of refractive amblyopia in Gazan children aged 4–12 years.
Methods: This was a hospital-based cross-sectional study using a purposive sampling method. Children aged 4–12 years who attended the Children’s Unit at Gaza Ophthalmic Hospital, Gaza Strip, Palestine from September 2019 to July 2020, were examined. A comprehensive eye test was conducted for all participants. Those who failed the eye examinations and were diagnosed with refractive amblyopia were included in the study. Demographic data and amblyopic refractive error patterns were analyzed accordingly.
Results: Of the 107 children, 72.9% were newly diagnosed with refractive amblyopia. The mean ± standard deviation (SD) of age of the children who participated was 7.85 ± 1.55 years. Approximately two-thirds of the patients were female (57.9%). Unilateral amblyopia was predominant in 60.7% of the cases. Moderate amblyopia was common (81.9%). A total of 149 amblyopic eyes were examined in total, with a mean ± SD (range) of best-corrected distance visual acuity and spherical equivalent of 0.45 ± 0.19 (0.2 to 1.3) logarithm of the minimum angle of resolution and + 0.76 ± 4.51 diopters (- 10.25 to + 11.50). Astigmatism was the most common amblyogenic factor (53.7%) among children with amblyopia.
Conclusions: The frequency of refractive amblyopia was 72.9%, and meridional amblyopia accounted for the highest percentage. Girls were more commonly affected than boys. The majority were in the 7-year-old age group. Most cases were unilateral with moderate refractive amblyopia. Our study yields insights into the patterns of refractive amblyopia among children in the Gaza Strip.

Background: To correlate multifocal visual evoked potential (mfVEP) findings with static automated perimetry (SAP) and spectral-domain optical coherence tomography (SD-OCT) in eyes with primary open angle glaucoma (POAG).
Methods: This cross-sectional study included a consecutive sample of 40 eyes of 40 patients with POAG. The participants underwent a complete ophthalmologic assessment, axial length (AL) measurement, and assessments with SAP, SD-OCT, and mfVEP.
Results: POAG cases were aged 49.70 ± 14.16 years (mean ± SD) and most were females (n = 24, 60%). For eyes of patients with POAG, the mfVEP upper-ring signal-to-noise ratio (SNR) showed a significant negative correlation with best-corrected logMAR visual acuity (r = - 0.33; P = 0.038), and a significant positive correlation with the superior hemifield of the visual field (VF) and the inferior-quadrant retinal nerve fiber layer (RNFL) thickness (r = + 0.34; P = 0.030; r = + 0.51; P < 0.001, respectively). Similarly, the mfVEP lower-ring SNR showed a significant negative correlation with best-corrected logMAR visual acuity (r = - 0.36; P = 0.024) and a significant positive correlation with the inferior hemifield of the VF and superior quadrant RNFL thickness (r = + 0.55; P < 0.001 and r = + 0.70; P < 0.001, respectively).
Conclusions: mfVEP is a promising tool for objective assessment of the VF in patients with POAG, as it is positively correlated with the VF and OCT RNFL thickness. Future longitudinal studies with a larger sample size and a specific glaucoma subtype, along with multiple follow-up evaluations, are warranted to confirm our preliminary results.

Background: To evaluate the normative values of corneal endothelial cell parameters within a group of healthy young Egyptian adults using specular microscopy and to examine any correlations between endothelial parameters and refractive or biometric parameters.
Methods: In this cross-sectional study, specular microscopy was used to study the right eyes of 150 healthy young volunteers and evaluated endothelial cell parameters, including cellular density, hexagonality (HEX), and coefficient of variation (CV) at 15 different points on the back corneal surface, which were later grouped into the central zone and either four quadrants or three annular zones. The same eyes underwent refractive and biometric assessments.
Results: Hundred fifty healthy adults were examined, and the age ranged from 20 to 30 years, with a median of 23 (interquartile range, 21–27) years. The mean ± standard deviation of central cell density was 2902.7 ± 270.7 cells/square millimeter. The superior paracentral area had the lowest mean density (2895.8 cells/square millimeter), but the highest mean HEX (67.7%), while the inferior peripheral area had the highest mean density (3100.5 cells/square millimeter) but the lowest mean HEX (64%). The difference in cell density among the three annular zones was not statistically significant (P = 0.365). However, HEX and CV in the central and paracentral zones differed statistically significantly from those of the peripheral zone (P < 0.001 and P = 0.014, respectively). Weak but non-significant correlations were detected between endothelial cell density and all measured refractive and biometric parameters.
Conclusions: The findings of this study provided useful normative biometric and specular data in a specific age group and a specific population, and could be useful in planning intraocular surgery in young Egyptian adults. However, future longitudinal studies with a larger sample could refine more endothelial cell parameter specifications over time.

Background: Many studies have used functional optical zone (FOZ) as a measure to compare different refractive laser treatment modalities. However, to our knowledge, no study has compared wavefrontoptimized (WFO) and wavefront-guided (WFG) laser in situ keratomileusis (LASIK) using FOZ. We compared the FOZ after WFO versus WFG LASIK in patients with myopia and myopic astigmatism.
Methods: In this prospective comparative study, we included 100 myopic eyes of 50 patients with or without astigmatism. They were divided into two groups according to the platform used: WFO or WFG femtosecond LASIK. Using Holladay’s equivalent keratometry reading (EKR) report of Pentacam HR, FOZ was defined as a zone centered on the pupil center with a standard deviation (SD) of 0.5 D, around the mean EKR. The differences in FOZ between the two platforms were analyzed at 3 months postoperatively. Visual acuity, refractive error, corneal asphericity (Q-value), and root mean square of higher-order aberrations (RMS for HOAs) were evaluated and compared.
Results: The mean ± SD of patient age was 26.64 ± 5.67 years. The preoperative characteristics of the two groups were comparable (all P > 0.05). The intended optical zone (IOZ) was 6 mm in both groups. The mean laser ablation depth was significantly greater in the WFG group (18 micrometre per D) than in the WFO group (16 micrometre per D) (P = 0.035). At 3 months postoperatively, the mean ± SD of FOZ diameter was 4.32 ± 0.94 mm (71.99 ± 15.68% of intended optical zone) in the WFO group and 4.16 ± 1.13 mm (69.33 ± 18.78% of intended optical zone) in the WFG group, with no significant difference between the two groups (P = 0.622). The change in corneal asphericity was greater in the WFG group than in the WFO group (P = 0.034). Postoperative mean corrected and uncorrected distance visual acuity, manifest refraction, and RMS for HOAs showed no significant difference between the two groups (all P > 0.05).
Conclusions: We found that WFG LASIK resulted in greater ablation depth and change in corneal asphericity than WFO LASIK at 3 months postoperatively. However, there was no significant difference in FOZ diameter, refractive error, and RMS for HOAs between the two groups. Further research is needed to confirm these findings.

Background: Surgical procedures are used as 1 of the main treatment modalities for pediatric glaucoma, even though progression may occur. In this study, we aimed to investigate the risk factors affecting the progression of pediatric glaucoma.
Methods: In this retrospective cohort study, we reviewed the medical records of patients diagnosed with pediatric glaucoma between April 2009 and March 2017. Pediatric glaucoma patients who underwent regular follow-up for at least 1 year were included. Demographics, intraocular pressure (IOP), central corneal thickness (CCT), axial length (AL), cup-to-disc ratio (C/D ratio), corneal diameter, type of glaucoma, age at time ofdiagnosis, and age at surgery were recorded. Progression was defined as an increase in AL > 2 mm, C/D ratio > 0.2, or corneal diameter > 1 mm during 1 year of follow-up.
Results: Eighty-three eyes from 46 patients were included: 37 eyes (45%) with primary congenital glaucoma (PCG), 46 eyes (55%) with secondary glaucoma, and 27 of these 83 eyes (32.5%) showed progression. Progression was comparable between eyes with PCG and secondary glaucoma (PCG, 22%; secondary glaucoma, 41%; P = 0.152). Age at the time of diagnosis and age at the time of the first surgery were significantly lower in the eyes with progression (P = 0.046 and 0.012, respectively). The mean ± standard deviation of surgeries in progressed versus non-progressed eyes was 1.88 ± 1.1 versus 1 ± 0.8 (P = 0.015). The frequency of comorbid systemic disease was significantly higher in patients with glaucoma progression (P = 0.043). The progressed and non-progressed eyes were comparable in terms of other demographic characteristics and ocular parameters (all P > 0.05).
Conclusions: Pediatric glaucoma patients who were younger at the time of diagnosis and the first glaucoma surgery and those with comorbid systemic disease are at higher risk of glaucoma progression. These findings are useful for clinicians when counseling parents of children with pediatric glaucoma about disease outcomes. However, future prospective studies with larger sample sizes and longer follow-up periods are needed to confirm our findings.