Medical Hypothesis, Discovery & Innovation (MEHDI) Ophthalmology Journal
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Pediatric cycloplegic refraction
Get PDFBackground: Cycloplegic refraction is an essential part of the pediatric ophthalmic assessment and is the cornerstone of strabismus evaluation. This narrative review aimed to ascertain the current scope of practice for cycloplegic refraction in the pediatric population.
Methods: An extensive literature review was conducted using ScienceDirect, PubMed/MEDLINE, Scopus, and Google Scholar databases using the following search terms: cyclopentolate, tropicamide, pediatric cycloplegia, atropine, homatropine, manual retinoscope, handheld autorefractometer, spherical errors, and no spherical errors of refraction in articles published from January 2000 to December 2022. Relevant retrieved references and practical points concerning pediatric cycloplegic refraction were summarized.
Results: Atropine has the most potent cycloplegic effect and is best used in cases of severe accommodative esotropia. Because of the unfavorable side effects and risks associated with atropine, cyclopentolate has been found to provide quite effective cycloplegia, even for moderate to severe hyperopia, and has become the standard agent for traditional pediatric cycloplegic exams. Tropicamide has also been shown to provide adequate cycloplegia while being less toxic and causing fewer side effects. Tropicamide has the fewest side effects and toxicity of all agents, while atropine has the most. Cyclopentolate is an exceptionally safe cycloplegic agent. To detect spherical and non-spherical refractive errors, refraction can be performed using a handheld autorefractometer or a manual retinoscope, as well as under general anesthesia in some cases. The optimal time to wear eyeglasses to maintain binocular vision and avoid amblyopia is also considered.
Conclusions: Accommodative power in children is at its maximum, and this interferes with reliable - assessment of refraction. Therefore, the use of cycloplegic refraction is mandatory during childhood to obtain actual refraction, which is considered the cornerstone for eyeglass prescription. Knowledge of the various cycloplegic agents used in childhood refraction is important for ophthalmologists and optometrists to obtain safe and effective cycloplegia. High refractive errors, as well as the presence of anisometropia or squint, necessitate the use of eyeglasses as early as childhood to maintain binocularity and depth perception
Neuro-ophthalmic features of patients with spontaneous cerebrospinal fluid leaks
Get PDFBackground: Increased intracranial pressure is a potential cause of spontaneous cerebrospinal fluid (sCSF) leak. Associated neuro-ophthalmic features have not been well studied, particularly relationships with idiopathic intracranial hypertension (IIH). We hypothesized that neuro-ophthalmic features routinely used in evaluations for IIH can be useful in the investigation of a causal relationship between IIH and sCSF leak. We reviewed the neuro-ophthalmic examination and office-based ophthalmic imaging data of all consecutive patients with sCSF leaks and at least one repair to investigate the clinical and neuro-ophthalmic features of increased intracranial pressure.
Methods: We conducted a retrospective longitudinal study at a single institution by querying the electronic medical record system for CSF leak Current Procedural Terminology (CPT) codes (G96.00 and G96.01) from June 1, 2019, to July 31, 2022. For patients with a confirmed diagnosis of sCSF leak, demographic information, eye examination results, and ophthalmic imaging details for both eyes were collected.
Results: A total of 189 patients with CSF leaks were identified through CPT coding; 159 had iatrogenic or traumatic CSF leaks, and 30 individuals (3 male, 27 female) had confirmed sCSF leaks. The mean age of patients with sCSF leaks was 46 years (range: 29 – 81), with a mean body mass index of 35.2 kg/m2 (range: 18.2 – 54.1). Only 11 of 30 underwent eye examinations (8 before surgical repair and 10 after). The mean pre-repair and post-repair best-corrected visual acuity were 20/30 (range: 20/20 – 20/55) and 20/25 (range: 20/20 – 20/40), respectively (P = 0.188). The mean retinal nerve fiber layer thickness was 99 mm (range: 96 – 104) pre-repair and 97 mm (range: 84 – 103) post-repair (P = 0.195). The mean ganglion cell complex thickness was 84 mm (range: 72 – 94) pre-repair and 82 mm (range: 71 – 94) post-repair (P = 0.500). Humphrey visual field average mean deviation was -5.1 (range: -12.4 – -1.8) pre-repair and -1.0 (range: -10.1 – 2.1) post-repair (P = 0.063).
Conclusions: Serial neuro-ophthalmic examinations are recommended for patients with sCSF leaks to screen for signs of current or prior increased intracranial pressure. Larger studies are required to clarify the longitudinal changes in neuro-ophthalmic features, to investigate the incidence of IIH in cases of sCSF leak development or recurrence after surgical repair, and to explore potential causal relationships to guide post-repair management and prevent recurrent leaks. A multicenter consortium is also suggested to develop a standard clinical protocol for comprehensive management of sCSF leaks.
 
Optic nerve head perfusion changes in eyes with proliferative diabetic retinopathy treated with intravitreal ranibizumab or photocoagulation: a randomized controlled trial
Get PDFBackground: Proliferative diabetic retinopathy (PDR) is a serious sight-threatening disease, and half of the patients with high-risk PDR can develop legal blindness within 5 years, if left untreated. This study was aimed at comparing panretinal photocoagulation (PRP) and intravitreal ranibizumab injections in terms of radial peripapillary capillary (RPC) density on optical coherence tomography angiography (OCTA) in patients with treatment-naive PDR.
Methods: This open-label, prospective, randomized clinical trial included 50 patients with treatment-naive PDR with optic disc neovascularization and randomized them into two groups: group 1, with patients undergoing two sessions of PRP 2 weeks apart, and group 2, with patients received three intravitreal ranibizumab injections (0.5 mg) 1 month apart for 3 consecutive months. Patients underwent a full ophthalmological examination, including best-corrected distance visual acuity (BCDVA) measurement in the logarithm of minimal angle of resolution (logMAR) notation and OCTA before intervention and monthly after the last laser session or the first intravitreal ranibizumab injection for 3 months of follow-up. Visual field (VF) was tested at the beginning and end of 3 months.
Results: Forty-two (84%) eyes completed the 3-month follow-up, including 22 eyes in the PRP group (88%) and 20 (80%) eyes in the ranibizumab group. The two groups were comparable in terms of demographic characteristics, diabetes duration, baseline BCDVA, glycated hemoglobin level, OCTA parameters, VF indices, and intraocular pressure (all P > 0.05). The RPC density change from baseline to the 3-month follow-up was significantly lower in the PRP group than in the ranibizumab group (mean difference in RPC density change: - 3.61%; 95% confidence interval: - 5.57% to - 1.60%; P = 0.001). The median (interquartile range) logMAR change from baseline to the 3-month follow-up (0.0 [0.2]) was significantly higher in the PRP group than in the ranibizumab group (- 0.15 [0.3]; P < 0.05). The median changes in central foveal thickness from baseline to the 3-month follow-up differed significantly between the two groups (P = 0.001).
Conclusions: In eyes with PDR and neovascularization of the disc RPC density on OCTA increased in the ranibizumab group and decreased in the PRP group. Visual acuity gain was higher in the ranibizumab group than in the PRP group. Future multicenter trials addressing our limitations are required to verify the findings of this study
Corneal topography and higher-order aberrations in patients with type 2 diabetes mellitus
Get PDFBackground: Changes in blood sugar levels cause alterations in the anterior segment and retina of the eye. This study was aimed at evaluating corneal topography, aberrometry, and corneal asphericity in patients with treatment-naive type 2 diabetes mellitus (T2DM).
Methods: Participants with treatment-naive T2DM were enrolled in this cross-sectional study. The inclusion criteria were glycated hemoglobin A1c (Hb A1c) greater than or equal to 7.5% and absence of other ocular or systemic diseases. Patients who refused to participate or had a history of topical or systemic steroid use, hyperlipidemia, hypertension, anemia, prior ocular disorder or surgery, diabetic retinopathy, glaucoma, cataract, active ocular inflammatory or infectious disease, or contact lens use were excluded. All participants underwent a comprehensive ophthalmic examination. The Pentacam HR Scheimpflug tomography system (Pentacam High Resolution; Oculus, Wetzlar, Germany) was used to measure the anterior-segment parameters.
Results: Sixty eyes of 30 patients with a male-to-female ratio of 1:1 were included; the mean (standard deviation [SD]) age and Hb A1c were 51.63 (6.73) years and 8.82% (1.31%), respectively. The mean (SD) values of central corneal thickness, root mean square (RMS) of total aberration, RMS of lower-order aberrations, RMS of higher-order aberrations, spherical aberration, 0° coma, 90° coma, flat anterior keratometry (K), steep anterior K, mean anterior K, anterior topographic astigmatism, flat posterior K, steep posterior K, mean posterior K, posterior topographic astigmatism, anterior corneal asphericity, and posterior corneal asphericity were 540.22 (24.47) µm, 1.72 (0.73) µm, 1.63 (0.73) µm, 0.51 (0.17) µm, + 0.31 (0.09) µm, - 0.06 (0.15) diopters (D), 0.003 (0.21) D, 43.87 (1.49) D, 44.69 (1.50) D, 44.28 (1.44) D, + 0.82 (0.83) D, - 6.25 (0.27) D, - 6.55 (0.31) D, - 6.40 (0.28) D, - 0.30 (0.15) D, - 0.32 (0.12) Q-value, and - 0.47 (0.17) Q-value, respectively.
Conclusions: We presented the mean values of Pentacam parameters for aberrometry, keratometry, and corneal asphericity in patients with treatment-naive T2DM. These values could serve as a baseline for prospective monitoring of the ocular health status of this cohort and for comparison with future cohorts of patients with well-controlled T2DM. Further studies are required to assess the presence and applicability of ocular changes following intensive blood glucose control in T2DM and further understand the related pathophysiology
Impact of vision correction on the visual impairment status and quality of life score in patients with type II diabetes mellitus
Get PDFBackground: Visual impairment (VI) in patients with diabetes mellitus (DM) worsens as the disease progresses. Therefore, quality of life (QOL) may also be affected. Furthermore, in the absence of macular involvement, some patients may benefit from visual intervention. However, not many Malaysians with known DM had their eyes screened or used correctable spectacles. Consequently, the QOL and VI status of patients with DM in Malaysia remain unclear. This study was aimed at determining the impact of optometric intervention on the QOL and VI status of adults with type II DM.
Methods: This was a quasi-self-controlled, experimental study involving adults with known type II DM. We conducted face-to-face interviews using the low vision quality-of-life questionnaire (LVQOL). The habitual visual acuity (VA) of all participants was recorded. All participants underwent fundus photography to grade diabetic retinopathy (DR) in both eyes. Correctable VA was determined following subjective refraction when the best-corrected distance visual acuity (BCDVA) was 6 /9 and better. After a 3-week adaptation to the prescribed refractive error correction, LVQOL was repeated via a phone interview.
Results: A total of 47 participants with type II DM, including 16 (34%) men and 31 (66%) women, with a mean (standard deviation [SD]) age of 49.0 (7.9) years were recruited. The age range was 32 – 59 years, and the baseline mean (SD) habitual binocular VA was 0.52 (0.31) decimal. Only 15% (n = 7 patients) of the participants had their vision tested and wore glasses; however, some were uncomfortable with the current corrections. All patients had undercorrected or uncorrected refractive errors, namely, hyperopic astigmatism (47%), myopic astigmatism (38%), hyperopia (6%), myopia (4%), and antimetropia (4%). Among the 47 participants, 89% (n = 42) had uncorrected presbyopia. The mean (SD) LVQOL score at baseline was 91.9 (17.3), which improved significantly with visual intervention to 122.8 (3.2) (P < 0.05). Refractive error corrections significantly improved the VI status (P < 0.05), as all participants achieved a BCDVA of 6 / 9 and better.
Conclusions: Our findings indicate that optometric intervention is effective in improving the LVQOL and VI status of adults with type II DM. Further clinical optometric studies on type II DM with DR with a longer follow-up should be carried out to understand the clinical characteristics of this cohort and the impact of meticulous refractions on QOL in providing better services in the future
Association of WDR36 polymorphisms with primary open-angle glaucoma
Get PDFBackground: Various genes contribute to the pathophysiology of primary open-angle glaucoma (POAG). The WD repeat domain 36 (WDR36) gene may participate in T cell activation and, hence, in the pathogenesis of POAG. We investigated the association of two WDR36 gene single nucleotide polymorphisms (SNPs) with POAG.
Methods: This cross-sectional study recruited patients aged >40 years with POAG and investigated the rs10038177 and rs1971050 SNPs of WDR36 using polymerase chain reaction and direct DNA sequencing. All participants underwent comprehensive ocular examination, visual field assessment using the Swedish Interactive Threshold Algorithm standard 24-2 threshold test, and measurement of peripapillary retinal nerve fiber layer thickness (RNFLT) using spectral domain optical coherence tomography.
Results: We enrolled 105 patients with a mean (standard deviation) age of 55.41 (8.56) years and a male-to-female ratio of 56 (53.3%) to 49 (46.7%), most of whom had a diagnosis of POAG for 2 to 5 years (60.0%). Most participants had diabetes (90.5%) but not hypertension (88.6%). There was a significant association of rs10038177 (P<0.05), but not rs1971050 (P>0.05), with family history of glaucoma. The association between rs10038177 and intraocular pressure was significant (P<0.05), but that between rs1971050 and intraocular pressure was not (P>0.05). No significant association was observed between mean cup-to-disc ratio and either SNP (both P>0.05). For rs10038177, a significant association was found only with the RNFLT of the superior quadrant (P<0.05), whereas for rs1971050, a significant association was found with the RNFLT of all four quadrants and average RNFLT (all P<0.05). However, pairwise comparisons revealed no significant differences between genotypes (P>0.05 for all pairwise comparisons). The association of rs10038177 with glaucoma severity was insignificant (P>0.05), and most patients with the TC genotype (71.7%) had moderate severity. There was no significant association between rs1971050 and glaucoma severity (P>0.05).
Conclusions: We observed genetic links between some, but not all, characteristics of POAG and the rs10038177 and rs1971050 SNPs of WDR36. Follow-up studies on these and other WDR36 SNPs in populations with different genetic backgrounds are necessary to confirm this genetic association
Monkeypox and the eye
Get PDFKEYWORDS
monkey pox, Orthopoxviruses, transmission, communicable disease, conjunctivitides, blepharitides, scleritides, keratitides, uveitides, acquired blindness, pandemic, COVID 1
Binocular vision parameters and body mass index
Get PDFBackground: Abnormal body mass Index (BMI) can adversely affect binocular vision. We aimed to assess the presence of possible differences in binocular vision parameters among the four BMI categories.
Methods: In this comparative cross-sectional study, we enrolled young adults and categorized them into underweight, normal weight, overweight, and obese groups based on their BMI. A complete orthoptic evaluation was performed to assess the mean values of binocular vision skills.
Results: We recruited 120 participants with a mean (standard deviation) age of 21.30 (1.80) years with best-corrected distance and near visual acuities of 6/6 and N6, respectively. The frequency of exophoria > 4 PD was high in the obese group. The frequency of binocular vision dysfunction was higher in the obese and underweight groups, with vergence dysfunction being the most common. The mean values for near negative fusional vergence (NFV), distance positive fusional vergence (PFV), negative relative accommodation, positive relative accommodation, monocular accommodation facility (AF), and monocular estimation method were comparable among the groups (all P > 0.05). The obese group had significantly receded near point of convergence, and reduced accommodative convergence to accommodation ratio and binocular AF than the normal, overweight, and underweight groups (all P < 0.05). The distance and near vergence facilities were significantly lower in the obese group than in the overweight and normal groups, and the distance vergence facility was significantly lower than in the underweight group (all P < 0.05). The mean values of distance NFV and near PFV in the obese group were significantly lower compared to the normal and overweight groups, and the mean values of distance NFV were significantly lower compared to the underweight group (all P < 0.05). The mean values of near PFV were significantly lower in the underweight group than in the overweight group (both P < 0.05). Both the underweight and obese groups had a significantly lower amplitude of accommodation compared to the normal group (both P < 0.05).
Conclusions: The frequency of binocular vision dysfunction was higher in the obese and underweight groups. Most convergence and some accommodation parameters were adversely affected in individuals with obesity. Being underweight adversely affects certain binocular vision skills. Further studies are required to determine the relevance of BMI as a predictor of binocular vision abnormalities
Association of metformin use with age-related macular degeneration risk
Get PDFBackground: The association between metformin use and reduced age-related macular degeneration (AMD) risk has been explored. Studies have shown a positive association, no association, or ambiguous results. The aim of this narrative review is to compile these divergent findings, and thereby, better assess the potential of metformin use in reducing the AMD risk.
Methods: Studies were extracted in two ways. First, a standard Google Scholar™ search was performed using the keywords “metformin” AND “macular degeneration” without language or time restrictions. The full texts of relevant articles identified in this search were retrieved and assessed, and articles of peer-reviewed original studies and meta-analyses were included. Second, the reference lists of the included articles were used to identify additional articles that satisfied the search algorithm and included in this review.
Results: Of the 12 studies included in this review, eight showed a positive correlation between metformin use and a reduced AMD risk, while one showed no association. Of the eight positive studies, seven were retrospective. Apart from the design, the studies were also diverse. The number of participants in each study ranged from over 300 to 30 million person-years. The study populations included those with type 2 diabetes mellitus, those with AMD, and those without either. The study locations were the United States, Europe, and Asia. The ambiguous or negative results from four studies could largely be rationalized based on the confounding factor of study design.
Conclusions: Most studies examined in this review demonstrated a positive association between metformin use and a reduced AMD risk. Studies not reporting such an association did not definitively demonstrate its absence. Overall, the studies reviewed herein support further clinical investigation of metformin as a prophylactic and potential treatment modality for AMD. Further randomized clinical trials with reasonably longer follow-up periods are necessary to determine the generalizability of the findings of studies reporting positive results
Vortex keratopathy after photorefractive keratectomy in a patient on long-term clozapine treatment
Get PDFBackground: Vortex keratopathy is a corneal entity characterized by corneal deposits at the level of the basal epithelium in the form of a whorl-like pattern in the interpalpebral portions of the cornea. Medications such as amiodarone, chloroquine, hydroxychloroquine, indomethacin, phenothiazines, ibuprofen, and naproxen bind to the cellular lipids of the basal epithelial layer of the cornea, producing a characteristic whorl pattern. Here, we report a case of bilateral central vortex keratopathy with slight vision impairment 3 weeks after uneventful photorefractive keratectomy (PRK) in a woman on long-term clozapine treatment.
Case Presentation: A 42-year-old woman presented to the outpatient clinic for refractive surgery for the correction of bilateral moderate myopia. Her best-corrected distance visual acuity was 20 / 20 in both eyes. She had been on antipsychotic clozapine tablets 400 mg / day for the past 6 years to manage a psychiatric disorder. On detailed preoperative slit-lamp examination, her corneas were clear, with perilimbal conjunctival pigmentations. Other ocular examination results were unremarkable. At the 3-week follow-up after an uneventful PRK, her uncorrected distance visual acuity was 20 / 25 in the right eye and 20 / 20 in the left eye, with complaints of slightly unclear vision in both eyes. Slit-lamp examination revealed bilateral corneal subepithelial deposits in a whorl-like pattern reminiscent of vortex keratopathy. The deposits were restricted to the epithelial and subepithelial regions and did not extend to the stroma without evident stromal haze. Dilated fundus examination results were normal bilaterally. Despite excellent refractive outcomes and visual acuity in both eyes, she was dissatisfied and complained of unclear vision. She was administered with lubricating eye drops and placed on regular follow-ups. At the 4-month follow-up, the vortex lines were cleared centrally, and she reported improvement in vision. Anterior-segment optical coherence tomography of the cornea revealed no epithelial deposits in the central part of the cornea and residual deposits in the temporal peripheral cornea, indicating clearing of the deposits from the central cornea and explaining the subjective improvement in vision. Her final best-corrected distance visual acuity was 20/20 in both eyes with an unremarkable ocular examination.
Conclusions: Our case indicates a potential causal relationship between long-term clozapine treatment and development of temporary, visually significant vortex keratopathy after uneventful PRK. Further large-scale studies are required to verify the causal relationship between the long-term clozapine administration and the development of vortex keratopathy following surface ablation photorefractive procedures