Vitamin A deficiency retinopathy in the setting of celiac disease and liver fibrosis.

PURPOSE: Vitamin A is a lipid-soluble compound that is critical in maintaining phototransduction. Ocular manifestations of hypovitaminosis A may present with anterior segment signs of xeropthalmia, with advanced cases also causing classic retinal and electrophysiologic changes of vitamin A deficiency retinopathy. We present a case of vitamin A deficiency retinopathy, with corresponding retinal imaging and electrophysiology, in an adult patient with celiac disease and liver fibrosis. METHODS: A single case report was conducted in Toronto, Canada. RESULTS: A 77-year-old male with known celiac disease and liver fibrosis presented progressively worsening vision noticed primarily when driving. Vision was 20/50 OD and 20/200 OS. Bitot spots were noted on anterior segment examination. Fundus photography demonstrated bilateral peripheral macular hypopigmentation and far-peripheral granular retinal hypopigmentation with focal yellow dots and hyper-pigmented deposits. Optical coherence tomography (OCT) imaging demonstrated indistinct outer retinal banding with mild outer nuclear layer thinning, focal hyper-reflective deposits, and a thin choroid bilaterally. Full-field electroretinography (ERG) testing demonstrated reduced rod-isolated and combined rod-cone response amplitudes, and multifocal ERG testing demonstrated blunted individual responses throughout the field. The patient was treated with pulse vitamin A therapy. After 6 months of therapy, ERG responses were back within reference range, and the outer retinal changes reversed; visual acuity improved to 20/30 OD and 20/40 OS. CONCLUSION: This case represents the classic findings of vitamin A deficiency retinopathy on fundus examination and electrophysiologic testing secondary to gastrointestinal pathology. Prompt treatment of high dose vitamin A supplementation led to improvement of full-field and multifocal ERG results, as well as reconstitution of outer retinal architecture.

Bilateral compressive optic neuropathy and outer retinopathy due to optic canal hyperostosis in a child with isolated vitamin a deficiency.

PURPOSE: Vitamin A plays a crucial role in rod phototransduction, with deficient levels manifesting as night blindness. Animal models have demonstrated bone dysplasia in the setting of hypovitaminosis A. We present a rare case of bony overgrowth leading to bilateral compressive optic neuropathy, combined with outer retinopathy, in a paediatric patient secondary to isolated vitamin A deficiency. METHODS: A single case report was conducted from Toronto, Canada. RESULTS: A 12-year-old boy with known autism spectrum disorder presented with a 9-month history of progressive painless vision loss. Vision was 20/300 and hand motion in the right and left eye, respectively. Fundus photography demonstrated bilateral optic atrophy and yellow lesions notably in the right eye far periphery. Optical coherence tomography (OCT) imaging demonstrated thinning of the retinal nerve fibre layer, alterations in the ellipsoid zone, as well as retinal pigment epithelium deposits. Computed tomography imaging demonstrated sphenoid bone thickening with narrow optic canals and moderate optic atrophy bilaterally. Full-field electroretinogram (ERG) demonstrated mildly reduced dark adapted (DA) 0.01 b-wave amplitudes and electronegative configuration of DA 3.0 and DA 10.0 ERG; the light adapted ERGs were normal. The patient was treated with pulse vitamin A therapy. Subsequently, the DA ERG normalized, outer retinal changes reversed and vision stabilised; no surgical intervention was conducted. CONCLUSION: This case represents a rare presentation of compressive optic neuropathy with concomitant outer retinopathy secondary to isolated vitamin A deficiency. Despite improvement in outer retinal integrity on OCT imaging and ERG testing results following vitamin A supplementation, no functional improvement was obtained due to severe optic atrophy.

Anesthesia for ophthalmic surgery: an educational review.

PURPOSE: Selecting an anesthetic agent for ophthalmic surgery has crucial implications for the surgeon, anesthesiologist, and patient. This educational review explores the common classes of anesthesia used in ophthalmology. Additionally, we discuss the considerations unique to cataract, glaucoma, strabismus, orbital, oculoplastic, and ocular trauma surgeries. METHODS: A comprehensive Embase search was performed using combinations of the subject headings "anesthesia", "eye surgery", "ophthalmology" and "cataract extraction", "glaucoma", "strabismus", "vitreoretinal surgery", "retina surgery", "eye injury", and "eyelid reconstruction". RESULTS: Topical anesthetics are the most commonly used form of ocular anesthesia, used in both an office and surgical setting, and carry a minimal side effect profile. Notably, topical anesthetics offer analgesia, but do not provide akinesia or amnesia. Regional blocks, such as are sub-Tenon's, peribulbar, and retrobulbar blocks, are used when akinesia is required in addition to analgesia. Recently, sub-Tenon's blocks have recently gained popularity due to their improved safety profile compared to other regional blocks. General anesthesia is considered for long, complex surgery, surgery in patients with multiple comorbidities, surgery in young pediatric patients, or surgery in patients intolerant to local or regional anesthetic. CONCLUSION: Anesthetizing the eye has rapidly evolved in recent years, supporting the safety, efficacy and comfort of ocular surgery. Since there are many viable options of anesthetics available for ophthalmic surgery, a robust understanding of the patients needs, the skill of the surgical team, and surgery-specific factors ought to be considered when creating an anesthetic plan for surgery.

Prospective evaluation of medical student accuracy conducting direct ophthalmoscopy with an unmodified iPhone X.

PURPOSE: To evaluate fundus examination accuracy of medical students when using an unmodified iPhone X or a direct ophthalmoscope in comparison to a staff ophthalmologist's retinal examination. METHODS: In this prospective comparative analysis, patients underwent dilated fundus examination by novice medical trainees using either an unmodified iPhone X or standard direct ophthalmoscope. The primary outcome was the mean difference and degree of agreement in cup-to-disc ratio between student examination and the staff ophthalmologist's cup-to-disc observation. RESULTS: A total of 18 medical students conducted 230 retinal examinations, 117 with the iPhone X and 113 with the direct ophthalmoscope. A greater proportion of students were unable to report cup-to-disc ratio using the iPhone X (81.2%) vs direct ophthalmoscope (30.1%). Student examination of cup-to-disc ratio led to a systematic bias (95% limits of agreement) of + 0.16 (-0.22 to + 0.54) and + 0.10 (-0.36 to + 0.56) with the iPhone X and direct ophthalmoscope, respectively. iPhone X and direct ophthalmoscope student observation concordance for optic disc colour (88.7 and 82.4%, respectively) and contour (68.3 and 74.2%, respectively) demonstrated low agreement with staff ophthalmologist findings. Student iPhone X observations demonstrated lower agreement with staff findings compared to direct ophthalmoscope observations for spontaneous venous pulsations (Cohen's Kappa = -0.044 vs 0.099). CONCLUSION: Amongst medical trainees, optic disc visualization using an unmodified iPhone X was inferior to the direct ophthalmoscope. When able to visualize the optic nerve head, there was no significant difference in reported cup-to-disc ratio between modalities. However, both modalities demonstrated poor reliability in comparison to staff ophthalmologist findings.

A proof of concept study to evaluate the treatment response of aflibercept in wARMD using OCT-A (Canada study).

PURPOSE: To Utilize OCT-A to measure the change in size (mm2) and density (flow index) of choroidal neovascular membranes (CNVMs) from baseline to week 52 of treatment-naïve wet age-related macular degeneration (wARMD) patients receiving intravitreal aflibercept injections (IAI). METHODS: Patients were treated with IAI at baseline, month 1 and month 2 and then every other month for a total of 12 months. Along with clinical examination and best corrected visual acuity (BCVA), OCT-A 6- and 3-mm scans were acquired at every visit between May 2017 and January 2019. Data from baseline, week 12 and week 52 were analyzed prospectively and included in the final analysis. RESULTS: Twenty-five eyes from 23 patients were included in the study. The mean BCVA at baseline and week 52 increased from 20/125 to 20/80, respectively (p < 0.001). The mean CST at baseline and week 52 decreased from 330.48 to 222.40 µm, respectively (p < 0.001). 1Seventeen patients (18 eyes) completed all protocol-based 6 × 6 mm and 3 × 3 mm OCT-A scans. In this subgroup, 6-mm OCT-A scans revealed that the mean size of the CNVM before and after IAI was 1.21 mm2 and 0.56 mm2, respectively (p < 0.001), while the 3-mm OCT-A scans at baseline and week 52 demonstrated a decrease in mean size of the CNVM from 0.89 to 0.37 mm2, respectively (p < 0.001). The 6-mm perfusion density map revealed no difference at either time points. CONCLUSIONS: OCT-A provides a useful approach for monitoring and evaluating the treatment of intravitreal aflibercept for CNVMs. Mean size of CNVMs can be identified by 3- or 6-mm scans, but without machine learning, it requires extensive segmentation. While reproducibility and clear delineation of CNVMs in wARMD using OCT-A is challenging, OCT-A does offer the ability to monitor CNVM size changes during treatment and may offer another biomarker to assist in assessing treatment response.

Preoperative measurements for cataract surgery: a comparison of ultrasound and optical biometric devices.

PURPOSE: To evaluate differences in preoperative measurements and refractive outcomes between ultrasound and optical biometry when using the Barrett Universal II intraocular lens (IOL) power formula. METHODS: In this consecutive case series, cataract extraction and IOL implantation cases from two surgical centers in Toronto, Canada, were recruited between January 2015 and July 2017. Differences between ultrasound (applanation or immersion A-scan) and optical biometry (IOLMaster 500) were compared for axial length (AL), anterior chamber depth and refractive outcomes. The primary outcome was the percentage of cases in each cohort within ± 0.50D of refractive error. RESULTS: In total, 527 cataract cases underwent IOLMaster testing. Of these, 329 eyes (62.4%) were also measured by applanation A-scan, and the other 198 eyes (37.6%) received immersion A-scan testing. Applanation ultrasound led to 5.8%, 16.0% and 46.4% of eyes within ± 0.25D, ± 0.50D and ± 1.00D of refractive error, respectively, whereas the IOLMaster 500 led to 48.5%, 77.1% and 94.9%, respectively (n = 293, ± 0.50D: p < 0.001). Immersion ultrasound led to 31.2%, 57.6% and 91.2% of eyes within ± 0.25D, ± 0.50D and ± 1.00D of refractive error, respectively, whereas the IOLMaster 500 led to 42.4%, 72.0% and 92.0%, respectively (n = 125, ± 0.50D: p = 0.001). Applanation (n = 329, A-scan AL: 23.64 ± 1.67 mm, IOLMaster AL: 24.20 ± 1.70 mm, p < 0.001) and immersion ultrasound (n = 198, A-scan AL: 25.01 ± 2.06 mm, IOLMaster AL: 25.08 ± 2.13 mm, p = 0.002) yielded significantly lower AL values compared to optical biometry measurements. CONCLUSIONS: Optical biometry yielded a significantly larger percentage of cases within ± 0.50D of refractive error compared to ultrasound biometry when using the Barrett Universal II IOL power formula.

A comparative analysis of 12 intraocular lens power formulas.

PURPOSE: To evaluate the accuracy of 12 intraocular lens (IOL) power calculations: Barrett Universal II, EVO, Haigis, Hill-RBF version 2.0, Hoffer Q, Holladay 1, Holladay 2, Kane, Olsen, SRK/T, Super Formula and T2. METHODS: In this retrospective consecutive case series, cataract extraction and IOL implantation cases in Toronto, Canada, were recruited between 2017 and 2019. Refractive predictions were compared to the observed 1-month postoperative spherical equivalent to determine the refractive error for each formula cohort. Subgroup analysis stratified eyes into short (≤ 22.5 mm)-, intermediate (22.5 mm-25.5 mm)- and long (≥ 25.5 mm)-axial length (AL) cohorts. The primary outcome was the percentage of cases within ± 0.50D of refractive error. RESULTS: Overall, 764 cataract cases were analyzed. Formulas with the highest percentage of eyes within ± 0.50D of refractive error, in decreasing order, were: Kane (77.7%), Barrett Universal II (77.4%), EVO (76.6%), T2 (76.4%), Super (75.9%), Holladay 1 (75.4%), Hill-RBF 2.0 (74.7%), SRK/T (72.6%), Hoffer Q (72.5%), Haigis (71.7%), Olsen (67.4%) and Holladay 2 (67.3%). For short-AL eyes, the Holladay 1 formula was most accurate (n = 69, 78.3% within ± 0.50D), and for long-AL eyes, the Barrett Universal II formula was most accurate (n = 116, 76.7% within ± 0.50D). Kane, Barrett, EVO, T2 and Super formulas led to a significantly lower mean absolute error compared to the open-source calculations with optimized lens constants (p-value: < 0.001-0.042). CONCLUSIONS: The Kane formula was the most accurate formula for the overall analysis. The Holladay 1 calculation was most accurate for short-AL cases, whereas the Barrett Universal II was superior for long-AL eyes.

Visual and Refractive Outcomes in Manual versus Femtosecond Laser-Assisted Cataract Surgery: A Single-Center Retrospective Cohort Analysis of 1838 Eyes.

PURPOSE: Femtosecond laser-assisted cataract surgery (FLACS) has emerged as an alternative to manual cataract surgery (MCS) for corneal incision and capsulorhexis creation, as well as nuclear fragmentation. This study compares postoperative refractive and visual outcomes in eyes receiving MCS or FLACS. DESIGN: Single-center, comparative, retrospective cohort analysis. PARTICIPANTS: Consecutive eyes receiving FLACS and MCS from July 1, 2012, to July 31, 2015, at a single tertiary care center. METHODS: Demographic data, ocular history, preoperative measurements and biometry, and postoperative surgical results were retrospectively obtained and statistically analyzed using a generalized linear mixed model adjusting for differences in baseline characteristics and within-patient correlation. A 2-tailed P value <0.05 was considered statistically significant throughout the study. MAIN OUTCOME MEASURES: Percentage of eyes achieving absolute error (AE) ≤0.5 diopters (D). Secondary outcomes included percentage of eyes with AE ≤0.25 D and ≤1.0 D, and percentage of distance-targeted eyes achieving uncorrected distance visual acuity (UDVA) of 20/20 or better, 20/25 or better, and 20/30 or better. RESULTS: A total of 883 eyes received MCS and 955 received FLACS among 1089 patients. Some 82.6% of FLACS eyes and 78.8% of MCS eyes had ≤0.5 D of AE at 3 weeks, representing an adjusted odds ratio (OR) of 1.28 (95% confidence interval [CI], 0.98-1.66) of FLACS relative to MCS being within target. Some 97.1% of FLACS and 97.2% of MCS eyes had ≤1.0 D of AE (OR, 0.96; 95% CI, 0.57-1.60) and 49.3% of FLACS and 46.3% of MCS eyes, ≤0.25 D of AE (OR, 1.13; 95% CI, 0.91-1.39). Factors predictive of a favorable refractive outcome included axial length between 22 and 24.8 mm, receiving a toric intraocular lens, less preoperative cylinder, and greater preoperative average keratometry. There was no significant difference in the percentage of patients targeted for distance who achieved UDVA of 20/20 or better (P = 0.30), 20/25 or better (P = 0.06), or 20/30 or better (P = 0.66) vision. CONCLUSIONS: Postoperatively, there was no statistically significant difference found between eyes undergoing FLACS and eyes undergoing MCS with respect to refractive and visual outcomes.

Subfoveal Choroidal Neovascular Membrane Secondary to Idiopathic Intracranial Hypertension.

Purpose: To present a rare case of subfoveal choroidal neovascular membrane (CNVM) secondary to idiopathic intracranial hypertension. Methods: A case was evaluated. Results: A 21-year-old woman presented with a 2-week history of painless blurred vision in the right eye. She described initial metamorphopsia and intermittent bitemporal headaches lasting 30 minutes. She denied pain with eye movements and a history of trauma. Her body mass index was 49 kg/m2. The visual acuity (VA) was 20/320 OD and 20/20 OS; there was no relative afferent pupillary defect. A dilated fundus examination showed bilateral optic disc edema and a subfoveal CNVM in the right eye. The patient was started on oral acetazolamide 500 mg twice daily and treated with 2 intravitreal antivascular endothelial growth factor (anti-VEGF) injections. Three months later, the VA was 20/30 in the right eye and the disc edema had improved. Conclusions: CNVMs in the setting of idiopathic intracranial hypertension-related papilledema may be subfoveal and have an excellent response to anti-VEGF agents.

Accuracy of an Artificial Intelligence Chatbot's Interpretation of Clinical Ophthalmic Images.

Importance: Ophthalmology is reliant on effective interpretation of multimodal imaging to ensure diagnostic accuracy. The new ability of ChatGPT-4 (OpenAI) to interpret ophthalmic images has not yet been explored. Objective: To evaluate the performance of the novel release of an artificial intelligence chatbot that is capable of processing imaging data. Design, Setting, and Participants: This cross-sectional study used a publicly available dataset of ophthalmic cases from OCTCases, a medical education platform based out of the Department of Ophthalmology and Vision Sciences at the University of Toronto, with accompanying clinical multimodal imaging and multiple-choice questions. Across 137 available cases, 136 contained multiple-choice questions (99%). Exposures: The chatbot answered questions requiring multimodal input from October 16 to October 23, 2023. Main Outcomes and Measures: The primary outcome was the accuracy of the chatbot in answering multiple-choice questions pertaining to image recognition in ophthalmic cases, measured as the proportion of correct responses. χ2 Tests were conducted to compare the proportion of correct responses across different ophthalmic subspecialties. Results: A total of 429 multiple-choice questions from 136 ophthalmic cases and 448 images were included in the analysis. The chatbot answered 299 of multiple-choice questions correctly across all cases (70%). The chatbot's performance was better on retina questions than neuro-ophthalmology questions (77% vs 58%; difference = 18%; 95% CI, 7.5%-29.4%; χ21 = 11.4; P < .001). The chatbot achieved a better performance on nonimage-based questions compared with image-based questions (82% vs 65%; difference = 17%; 95% CI, 7.8%-25.1%; χ21 = 12.2; P < .001).The chatbot performed best on questions in the retina category (77% correct) and poorest in the neuro-ophthalmology category (58% correct). The chatbot demonstrated intermediate performance on questions from the ocular oncology (72% correct), pediatric ophthalmology (68% correct), uveitis (67% correct), and glaucoma (61% correct) categories. Conclusions and Relevance: In this study, the recent version of the chatbot accurately responded to approximately two-thirds of multiple-choice questions pertaining to ophthalmic cases based on imaging interpretation. The multimodal chatbot performed better on questions that did not rely on the interpretation of imaging modalities. As the use of multimodal chatbots becomes increasingly widespread, it is imperative to stress their appropriate integration within medical contexts.

Full-Thickness Macular Hole Due to Choroidal Neovascularization in the Setting of Pathologic Myopia.

Purpose: To present a case of myopic choroidal neovascularization (CNV) leading to a full-thickness macular hole (MH) in a patient with macular schisis. Methods: A single case was evaluated. Results: A 65-year-old woman presented with myopic staphyloma and foveoschisis in both eyes. One month after the baseline presentation for myopic macular schisis, the patient presented with a paracentral scotoma in the left eye. Examination showed a submacular hemorrhage in the left eye. Optical coherence tomography of the left eye showed subretinal fluid and subretinal hyperreflective material in the fovea, suggestive of exudative myopia, and a small full-thickness MH (diameter 86 µm). After anti-vascular endothelial growth factor injections, the CNV showed interval improvement; however, a larger full-thickness MH (diameter 287 µm) developed in the left eye. Conclusions: A full-thickness MH developed secondary to CNV, leading to foveal dehiscence in an eye with baseline macular schisis.

SPONTANEOUS RESOLUTION OF RETINOSCHISIS IN THE SETTING OF NARROW-ANGLE GLAUCOMA: A CASE REPORT.

PURPOSE: To present a rare case of retinoschisis in the setting of narrow-angle glaucoma that demonstrated spontaneous resolution with conservative management. METHODS: Case report presentation from the Vitreous Retina Macula Specialists of Toronto in December 2020. RESULTS: A 65-year-old woman with previous bilateral laser peripheral iridotomies for narrow-angle glaucoma was referred to a tertiary retina clinic for the assessment of query macular edema in the left eye. The patient presented with a blunted foveal reflex in the left eye, and optical coherence tomography imaging demonstrated diffuse retinoschisis of outer retinal layers in the peripapillary region and nasal macula. The patient elected for conservative management, and by 10-month follow-up, her retinoschisis resolved spontaneously. CONCLUSION: Only seven cases of retinoschisis in the setting of narrow-angle glaucoma have been identified in the literature. This is the first case in this setting to demonstrate spontaneous resolution with conservative management. Although laser peripheral iridotomies have been shown to resolve retinoschisis in narrow-angle glaucoma patients, clinicians should be aware of a conservative management approach to yield a positive improvement in retinal integrity.

Factors contributing to the carbon footprint of cataract surgery.

The healthcare sector is a significant greenhouse gas emitter. Cataract surgery is a procedure that results in a large amount of carbon dioxide (CO2) emissions. We sought to review the literature for factors contributing to the carbon footprint of this procedure. The literature, although limited, varies greatly by region. The carbon footprint of cataract surgery ranged from approximately 6 kg CO2 equivalents in a center in India to 181.9 kg CO2 equivalents in a center in the United Kingdom. Factors contributing to the carbon footprint of cataract surgery included the procurement of materials, energy use, and the emissions associated with travel. Factors facilitating a lower carbon footprint include the reuse of surgical materials and more efficient autoclave settings. Potential areas for improvement to consider include the reduction in packaging material, the reuse of materials, and potentially reducing travel emissions by performing simultaneous bilateral cataract surgery.

Association Between Vitamin Deficiencies and Ophthalmological Conditions.

Vitamin deficiencies can have adverse effects on health, including on the visual system. The ocular manifestations of a vitamin deficiency are related to the underlying biochemical function of the particular nutrient. While vitamin deficiencies are not common in developed counties, they are still prevalent in parts of the developing world and in specific, vulnerable populations. Vitamin deficiencies can cause or contribute to many ophthalmological conditions and eye diseases may even be the first presenting finding of a vitamin deficiency. As such, it is important for ophthalmologists to be aware of the ocular manifestations of vitamin deficiencies, especially given that the complications can be severe and effectively treated if identified early. This review summarizes the literature on the main vitamins known to have characteristic ocular manifestations: vitamins A, B1, B2, B9, B12, C, D, E and K. The function, epidemiology, manifestations, workup, and management of each vitamin is discussed in detail.

Deep learning model to identify homonymous defects on automated perimetry.

BACKGROUND: Homonymous visual field (VF) defects are usually an indicator of serious intracranial pathology but may be subtle and difficult to detect. Artificial intelligence (AI) models could play a key role in simplifying the detection of these defects. This study aimed to develop an automated deep learning AI model to accurately identify homonymous VF defects from automated perimetry. METHODS: VFs performed on Humphrey field analyser (24-2 algorithm) were collected and run through an in-house optical character recognition program that extracted mean deviation data and prepared it for use in the proposed AI model. The deep learning AI model, Deep Homonymous Classifier, was developed using PyTorch framework and used convolutional neural networks to extract spatial features for binary classification. Total collected dataset underwent 7-fold cross validation for model training and evaluation. To address dataset class imbalance, data augmentation techniques and state-of-the-art loss function that uses complement cross entropy were used to train and enhance the proposed AI model. RESULTS: The proposed model was evaluated using 7-fold cross validation and achieved an average accuracy of 87% for detecting homonymous VF defects in previously unseen VFs. Recall, which is a critical value for this model as reducing false negatives is a priority in disease detection, was found to be on average 92%. The calculated F2 score for the proposed model was 0.89 with a Cohen's kappa value of 0.70. CONCLUSION: This newly developed deep learning model achieved an overall average accuracy of 87%, making it highly effective in identifying homonymous VF defects on automated perimetry.