Medical hypothesis, discovery & innovation in optometry

Background: Humanitarian missions and mobile camp surgeries have pivotal roles in the uptake of cataract surgery in areas with limited resources. Ocular biometry is an important preoperative evaluation tool for cataract surgery candidates. Herein, we report the distributions of ocular biometric values among cataract surgery candidates in camp settings in southern Nigeria.
Methods: In this cross-sectional study, we retrieved data from consecutive patients scheduled for cataract surgery. All patients underwent a full ophthalmic examination using a slit-lamp biomicroscope. Age, sex, and preoperative biometric values, including anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD), and axial length (AL), together with intraocular lens (IOL) power, were documented. Biometric values were obtained using A-mode ultrasonography.
Results: Records of 567 patients with a mean (standard deviation) age of 66.0 (13.4) years revealed a male-to-female sex ratio of 1:1.24. Most participants were in the 66–70-year age group. Mean IOL power was significantly different between males and females (P < 0.001). However, the biometric values were comparable between sexes (all P > 0.05). There were significant differences in the mean IOL power (P < 0.001) and ACD (P < 0.05) between the age groups, indicating a decrease in ACD with age. However, the other biometric parameters were comparable between the age groups (all P > 0.05). ACD had a significant weak negative correlation with LT (r = - 0.16; P < 0.001) and IOL power (r = - 0.22; P < 0.001) and a positive correlation with AL (r = + 0.24; P < 0.001). LT had a significant weak negative correlation with VCD (r = - 0.16; P < 0.001) and a positive correlation with AL (r = + 0.09; P < 0.05). VCD had significant moderate positive and negative correlations with AL (r = + 0.39; P < 0.001) and IOL power (r = - 0.34; P < 0.001), respectively. AL had a significant strong negative correlation with IOL power (r = - 0.78; P < 0.001).
Conclusions: This study presents the mean distributions of ocular biometric parameters among cataract surgery candidates in camp settings in southern Nigeria. Age and sex were important determinants of IOL power and should be considered when planning eye camp supplies. AL had a strong inverse correlation with IOL power. Further multicenter national studies are required to verify these preliminary findings.

Background: Astigmatism is a common refractive error. If left untreated, it may result in blurred or distorted vision. We determined the prevalence of astigmatism in schoolchildren aged 6–16 years in Mumbai, India.
Methods: A cross-sectional study was conducted using a stratified cluster random sampling method. We included primary and secondary schoolchildren aged 6–16 years. All children underwent a comprehensive eye examination. Astigmatism was characterized as having a diopter cylinder (DC) power of 0.50 or more in at least one eye, and for prevalence estimation, we reported the number of children with astigmatism. Astigmatism severity was defined as mild (less than or equal to - 1.50 DC), moderate (- 1.50 DC to - 2.50 DC), and severe (> - 2.50 DC). Based on the axis orientation, astigmatism was categorized as with-the-rule, against-the-rule, and oblique.
Results: A total of 3151 schoolchildren with a mean (standard deviation) age of 12.1 (2.9) years were screened; boys and girls accounted for 49.22% and 50.78%, respectively. Age groups of 6–9, 10–13, and 14–16 years accounted for 51.35%, 28.53%, and 20.12%, respectively. The overall prevalence of astigmatism was 11.46%, with no significant difference between sexes (P > 0.05). The prevalences of astigmatism in the groups aged 6–9-, 10–13-, and 14–16 years were 5.24%, 3.49%, and 2.73%, respectively. Prevalence differed significantly among age groups (P < 0.05), with a trend of decreasing prevalence with increasing age. No significant association was found between age and severity of astigmatism (P > 0.05). The prevalences of mild, moderate, and severe astigmatism were 6.51%, 3.11%, and 1.84%, respectively. Mild astigmatism was significantly more prevalent than moderate (P < 0.05) or severe astigmatism (P < 0.05). The prevalence of astigmatism differed significantly among the three orientations of axis (P < 0.001). The prevalences were 9.20%, 1.68%, and 0.57% for with-the-rule, against-the-rule, and oblique astigmatism, respectively. We found a statistically significant difference in the prevalences of astigmatism based on the axis orientation between boys and girls (P < 0.05) and between age groups (P < 0.001), with a decreasing trend observed with increasing age.
Conclusions: We found a prevalence of 11.46% for astigmatism among schoolchildren aged 6–16 years in Mumbai, India. There was a decreasing trend in prevalence with increasing age, with no difference between sexes. The prevalence was the highest for mild astigmatism, followed by moderate and severe astigmatism. Prevalence differed significantly based on the axis orientation among the three subtypes, age groups, and between the two sexes, with a decreasing trend with increasing age. With-the-rule astigmatism was the most common, followed by against-the-rule astigmatism; oblique astigmatism was the least common.

Background: Optical coherence tomography angiography (OCTA) is used to quantify optic nerve blood flow in patients with primary open-angle glaucoma (POAG). Intrapapillary vessel density (iVD) has a high diagnostic accuracy for differentiating healthy from glaucomatous eyes. We compared the iVD of patients with POAG with that of healthy controls in an Egyptian tertiary referral center.
Methods: This cross-sectional study consecutively recruited patients with medically controlled POAG and age- and sex-matched healthy individuals. All study participants underwent a detailed medical history evaluation and comprehensive ophthalmic examination, with recording of the cup-to-disc ratio (C/D ratio) and intraocular pressure (IOP). Humphrey visual field evaluation using the standard 24-2 program was performed and global indices, including mean deviation (MD) and pattern standard deviation (PSD), were extracted. OCTA and spectral-domain (SD) OCT images were obtained. Average thickness of the retinal nerve fiber layer (RNFL) and thicknesses in the superior, inferior, nasal, and temporal quadrants were recorded. OCTA imaging was used to measure vessel density, and the automatically processed data for iVD were extracted.
Results: We included 86 eyes, 43 in the POAG and 43 in the healthy control group, with male predominance in both groups and mean (standard deviation [SD]) ages of 42.1 (9.4) and 39.3 (9.6) years, respectively. The two groups were comparable in terms of mean age, sex ratio, laterality of the included eyes, and mean IOP (all P > 0.05). The mean (SD) C/D ratio, MD, and PSD were significantly higher in the POAG group than in the control group (all P < 0.01). The mean (SD) average RNFL thickness and RNFL thicknesses in the four quadrants were significantly less in glaucomatous eyes than in healthy control eyes (all P < 0.05). Eyes with POAG had a significantly lower mean (SD) iVD than healthy control eyes (P < 0.01). Linear regression analysis revealed a significant positive correlation between iVD and average RNFL thickness (r = + 0.52; P < 0.001) and a significant negative correlation between iVD and PSD (r = - 0.31; P = 0.042) in eyes with POAG.
Conclusions: The structural, vascular, and functional parameters measured in this study deteriorated in eyes with POAG compared to controls. Significant circumpapillary RNFL thinning correlated well with reduced iVD in eyes with POAG. Similarly, a lower iVD detected using OCTA had a significant inverse correlation with PSD in the perimetry of eyes with POAG. Further studies with additional parameters and longer follow-up periods are required to verify our preliminary findings.

Background: Band keratopathy is a chronic, degenerative corneal disease resulting from gradual calcium deposition in the superficial cornea. Herein, we report the spectrum of causes, treatment outcomes, and recurrence rates of band keratopathy at a tertiary referral center throughout one decade.
Methods: This retrospective study included patients with clinical diagnoses of band keratopathy who were treated with combined ethylenediaminetetraacetic acid (EDTA) and superficial keratectomy with or without amniotic membrane transplantation (AMT). Patient medical records were reviewed, and detailed demographic and ophthalmological data, such as baseline and last follow-up best-corrected distance visual acuity (BCDVA), ocular or medical comorbidities, type of intervention, postoperative follow-up duration, relevant complications, and recurrence were recorded.
Results: A total of 32 eyes of 29 patients with 3 (10.3%) bilateral and 26 (89.7%) unilateral cases of treatment-requiring bank keratopathy were included. The mean (standard deviation [SD]) (range) age was 39.4 (22.4) (2–74) years, and most patients were female. The most common secondary cause was previous vitreoretinal surgery with silicone oil tamponade (15.6%); however, idiopathic cases were the most common (18.8%). Systemic comorbidities were present in 27.6% of patients, consisting of hypertension, diabetes mellitus, epilepsy, coronary artery disease, Behcet’s disease, and juvenile idiopathic arthritis; however, none of the patients had systemic diseases associated with hypercalcemia. Two of the 3 patients with bilateral involvement had chronic uveitis secondary to systemic rheumatological disease. The mean (SD) follow-up duration was 5.6 (4.0) years, and no serious postoperative complications occurred. The mean (SD) baseline and final BCDVA in logarithm of the minimum angle of resolution (logMAR) were 1.98 (1.0) and 1.7 (1.0), respectively (P > 0.05). Combined EDTA chelation and superficial keratectomy with and without AMT were performed in 12.5% and 87.5% of eyes, respectively. Recurrence was observed in 37.5% of eyes within the mean (SD) (range) follow-up of 9.4 (9.1) (1–32) months. Seven of the 12 eyes with recurrence underwent re-EDTA chelation combined with superficial keratectomy and AMT; however, 5 patients managed conservatively.
Conclusions: In this study, band keratopathy requiring intervention more commonly affected female individuals and was unilateral. Most cases were idiopathic. Systemic comorbidities were present in approximately one-third of cases. Managing band keratopathy using a combination of EDTA chelation and superficial keratectomy with or without AMT could be a potential treatment modality. Further large-scale studies are required to provide robust conclusions regarding the efficacy and safety of this management approach.

Background: The eye undergoes a series of physiological changes during pregnancy in response to metabolic and hormonal adaptation. Preeclampsia (PE) is the main cause of maternal morbidity and is associated with serious pregnancy-related complications. Characterized by hypertension and proteinuria, PE affects 2–8% of pregnancies globally. Previous studies have indicated that PE compromises retinal health. We examined the effects of PE on retinal structure and vasculature.
Methods: We conducted a literature review by searching PubMed/MEDLINE, Embase, and Scopus using terms pertaining to PE and the retina. The review included articles published between January 1, 1990, and May 30, 2024. The articles were selected based on their relevance to the topic. The key findings are summarized to offer a comprehensive overview of current knowledge, highlight the pathophysiology and manifestations of PE-related retinal changes, and propose clinical implications, diagnostic clues, and management strategies.
Results: PE is associated with visual disturbances caused by various retinal changes, including arteriolar narrowing, vasospasm, hemorrhages, exudates, serous retinal detachment, macular edema, retinal vein occlusion, and choroidal ischemia. These are mostly evident on fundus examination and frequently resolve postpartum. The underlying pathophysiology involves endothelial dysfunction, hypertension, inflammation, and coagulopathy. These retinal changes have immediate clinical implications and long-term risks, necessitating early detection, prompt multidisciplinary management, and close follow-up. Although most PE-associated retinal disturbances spontaneously resolve after the termination of pregnancy, one-third of patients are likely to experience long-lasting consequences
Conclusions: Visual disturbances may precede and portend the onset of PE. Early detection and prompt management will mitigate fetal and maternal morbidity and mortality. Understanding the underlying pathophysiology of PE-related retinal manifestations is crucial for optimal management, because the majority of manifestations are reversible. Although retinal changes secondary to PE typically resolves postpartum, some studies demonstrated that women with PE may have a higher long-standing risk of ocular disorders. A multidisciplinary team approach involving obstetricians, ophthalmologists, and healthcare providers is essential for the immediate and long-term management of ocular consequences in pregnancy. Consequently, additional studies associated with robust methodologies are required to develop clinical guidelines.

Background: False-negative and false-positive results in Toxoplasma serology are possible, and this could be misleading. Here, we report the case of a boy with Toxocara-associated panuveitis who was initially treated for toxoplasmosis owing to false-positive Toxoplasma immunoglobulin M (IgM) serology.
Case Presentation: A nine-year-old boy presented with intermittent headaches and blurred vision in the left eye. Close contact with domesticated animals was remarkable in the patient’s history. Upon examination, vision was 20/400 in the left eye. Slit-lamp examination revealed anterior chamber cells and flare without keratic precipitates, with vitreous cells and veils, optic disc edema, and a blurred fundus appearance. A systemic investigation revealed the presence of anti-Toxoplasma IgM antibodies. Treatment was initiated using topical cycloplegic and corticosteroid eye drops, in addition to oral trimethoprim/sulfamethoxazole. Oral corticosteroids were also administered. As the inflammation resolved, an inferior tractional detachment was detected on fundus examination, leading to the ultimate diagnosis of ocular toxocariasis. An enzyme-linked immunosorbent assay was positive for serum Toxocara antibodies. A fourteen-day course of oral albendazole was ordered by the pediatric infectious disease service because of the concern for visceral larva migrans, while topical eye drops were continued and oral prednisone was tapered. One month later, visual acuity in the left eye had improved to 20/70. The anterior chamber inflammation resolved; however, some vitreous cells and optic disc edema persisted. The inferior tractional detachment was much better visualized, and a peripheral granuloma was observed. Four months later, without any oral or topical medications, the patient’s visual acuity had improved to 20/30 and his eye had no active inflammation. The patient has been followed up for two years and has never developed any other lesions.
Conclusions: False-positive results on Toxoplasma serology and diffuse vitritis from toxocariasis that limited retinal visualization complicated the initial diagnosis in this case. In diagnosing the etiology of uveitis, ocular examination and detailed history taking should be emphasized, as laboratory results may be misleading.