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Yu XT, Rong SS. Genome-Wide Associations and Confirmatory Meta-Analyses in Diabetic Retinopathy. Genes (Basel) 2023;14(3)Abstract
The present study aimed to summarize and validate the genomic association signals for diabetic retinopathy (DR), proliferative DR, and diabetic macular edema/diabetic maculopathy. A systematic search of the genome-wide association study (GWAS) catalog and PubMed/MELINE databases was conducted to curate a comprehensive list of significant GWAS discoveries. The top signals were then subjected to meta-analysis using established protocols. The results indicate the need for improved consensus among DR GWASs, highlighting the importance of validation efforts. A subsequent meta-analysis confirmed the association of two SNPs, rs4462262 (ZWINT-MRPS35P3) (odds ratio = 1.38, p = 0.001) and rs7903146 (TCF7L2) (odd ratio = 1.30, p < 0.001), with DR in independent populations, strengthening the evidence of their true association. We also compiled a list of candidate SNPs for further validation. This study highlights the importance of consistent validation and replication efforts in the field of DR genetics. The two identified gene loci warrant further functional investigation to understand their role in DR pathogenesis.
Resnick HH, Bear MF, Gaier ED. Partial Recovery of Amblyopia After Fellow Eye Ischemic Optic Neuropathy. J Neuroophthalmol 2023;43(1):76-81.Abstract
BACKGROUND: Recovery from amblyopia in adulthood after fellow eye (FE) vision loss is a well-known phenomenon. Incidence of recovery varies widely following different FE pathologies, and the rate of recovery after FE ischemic optic neuropathy (ION) has not been examined. We aimed to determine the frequency and degree of improvement in amblyopic eye (AE) visual function after ION in the FE. METHODS: We performed a retrospective chart review of patients between 2007 and 2021 confirmed to have amblyopia and ischemic optic neuropathy in different eyes. Patients with unstable ocular pathology potentially limiting vision were excluded. We compared the best-corrected visual acuity (VA) in each eye before and after FE ION over time. For patients with available data, we examined change in perimetric performance over time. RESULTS: Among the 12 patients who met the inclusion criteria (mean age 67 ± 8 years), 9 (75%) improved ≥1 line and 2 (17%) improved ≥3 lines. The median time from ION symptom onset to maximal improvement was 6 months (range: 2-101 months). Reliable perimetric data were available for 6 patients. Mean sensitivity improved in the AE for all patients, with mean improvement of 1.9 ± 1.1 dB. There was no correspondence between foci of ION-related field loss and gains in field sensitivity in the AE. CONCLUSIONS: A high proportion of patients with amblyopia and contralateral ION experience improvement in AEVA. Modest gains in perimetric sensitivity in the AE may accompany FE ION. These findings support the view that residual plasticity in the adult visual cortex can be tapped to support functional improvement in amblyopia.
Philip AM, Fernandez-Santos CC, Ramezani K, Dolinko AH, Manhapra A, Look-Why S, Chang PY, Foster SC, Anesi SD. Ocular Mucus Membrane Pemphigoid: A Primary Versus Secondary Entity. Cornea 2023;42(3):280-283.Abstract
PURPOSE: The purpose of this review was to investigate the idea that inflammatory events of the conjunctiva and ocular surface may act as triggering events for the onset of ocular mucus membrane pemphigoid (oMMP). METHODS: A retrospective chart review of patients with biopsy-proven oMMP and no systemic pemphigoid disease. The presence, or absence, of the following inflammatory conditions at the time of OMMP diagnosis was noted: significant eyelid disease, significant atopic eye disease, Stevens-Johnson syndrome, graft-versus-host disease, viral keratitis, sarcoidosis with ocular involvement, chemical burns, medicamentosa, Sjogren syndrome, systemic lupus erythematosus with ocular involvement, and epidemic keratoconjunctivitis. Response to immunomodulatory therapy (IMT) was also recorded. RESULTS: A total of 779 patient records were identified. Conjunctival biopsy was present in 724 patients, with 646 (89.2%) being positive. One hundred thirty-nine patients (21.5%) with positive biopsies had extraocular pemphigoid disease and were excluded from further analysis. Of the 507 included patients, 154 (30.4%) had at least one of the specified inflammatory conditions present at the time of OMMP diagnosis. One hundred eighteen patients (23.3%) had only 1 such condition, 35 (6.9%) had 2, and 1 patient had 3. In patients with at least one of these conditions present, response to IMT was seen in 84.9% of patients with sufficient follow-up. CONCLUSIONS: Our study suggests that oMMP may arise as a secondary pathology to acute inflammatory events or chronic inflammatory states of the conjunctiva and ocular surface.
Yadav AK, Choudhary SS, Pawar NM, Velaga NR. Investigating the role of beliefs in influencing the hand-held and hands-free mobile phone use among pedestrians in India. Int J Inj Contr Saf Promot 2023;30(1):79-90.Abstract
Mobile phone distraction is a significant contributor to pedestrian injuries. However, mobile phone engagement among pedestrians has been scarcely explored in a developing country like India. The present study utilized the beliefs-based theory of planned behaviour to examine the association between pedestrian beliefs towards distracted walking (behavioural, normative, and control) and their mobile phone use frequencies. Based on a survey of 560 pedestrians (64.6% males), it was found that the major use of mobile phones was for listening to music (30.7%), followed by receiving a call (25%), making a call (18.9%), texting (9.8%), navigation (8.5%) and internet browsing (7.1%). A series of multivariate ANOVAs and logistic regression models were developed to investigate the relationships between the beliefs and frequencies of mobile phone use in hands-free and hand-held conditions. Significant multivariate differences were found for behavioural and normative beliefs in hands-free conditions and all three types of beliefs in hand-held conditions. The frequency of mobile phone use was significantly predicted by normative beliefs (p < 0.001) in the hands-free condition, and by behavioural (p = 0.041) and normative beliefs (p = 0.004) in the hand-held condition. The findings may assist the road safety countermeasures in addressing the issue of pedestrian distraction.
Trofimov AV, Aronow ME, Bussière MR, Gragoudas ES, Keane FK, Kim IK, Shih HA, Bhagwat MS. In Reply to Elmali and Yazici. Int J Radiat Oncol Biol Phys 2023;115(3):810-811.
Butler NJ, Cohen D, Yu Y, Kempen JH, Sobrin L, VanderBeek BL. Dual-Energy X-Ray Absorptiometry Scan Utilization and Skeletal Fragility Among Non-Infectious Uveitis Patients Exposed to Oral Glucocorticoids. Ocul Immunol Inflamm 2023;:1-9.Abstract
INTRODUCTION: Currently, little is known regarding bone health surveillance for glucocorticoid-exposed non-infectious uveitis (NIU) patients or their baseline risks of skeletal fragility outcomes. METHODS: Using claims data, we calculated rates of dual-energy x-ray absorptiometry (DXA) screening for glucocorticoid-exposed NIU and rheumatoid arthritis (RA) patients. Separately, we compared risks of skeletal fragility metrics amongst NIU patients, RA patients, and controls, independent of glucocorticoid use. RESULTS: The adjusted hazard ratio (aHR) of NIU patients to have a DXA scan was 0.64 (95% CI, 0.63-0.65; p < .001) compared to RA patients. The aHR for any skeletal fragility outcome amongst NIU patients was 0.97 (p < .02) compared to normal controls, while RA patients had excess risk (aHR, 1.15; p < .001). CONCLUSIONS: NIU patients are 36% less likely to receive a DXA scan after high-dose glucocorticoid exposure compared with RA patients. No elevated risk of osteoporosis for NIU patients was found compared to normal controls.
Ahmed I, Hoyek S, Patel NA. Global Disparities in Retinopathy of Prematurity: A Literature Review. Semin Ophthalmol 2023;38(2):151-157.Abstract
PURPOSE: To provide an overview of the impact of retinopathy of prematurity (ROP), and the challenges in the screening, diagnosis, and treatment of ROP worldwide. METHODS: A comprehensive search was conducted using the PubMed database from January 2011 to October 2021 using the following keywords: retinopathy of prematurity, laser, and anti-vascular endothelial growth factor (VEGF). Data on patient characteristics, ROP treatment type, and recurrence rates were collected. The countries included in these studies were classified based on 2021-2022 World Bank definitions of high, upper-middle, lower-middle, and low-income groups. Moreover, a search for surgical outcomes for ROP and screening algorithms and artificial intelligence for ROP was conducted. RESULTS: Thirty-nine studies met the inclusion criteria. ROP treatment and outcomes showed a trend towards intravitreal anti-VEGF injections as the initial treatment for ROP globally and the treatment of recurrent ROP in high-income countries. However, laser remains the treatment of choice for ROP recurrence in middle-income countries. Surgical outcomes for ROP stage 4A, 4B and 5 are similar worldwide. The incidence of ROP and ROP-related visual impairment continue to increase globally. Although telemedicine and artificial intelligence offer potential solutions to ROP screening in resource-limited areas, the current models require further optimization to reflect the global diversity of ROP patients. CONCLUSION: ROP screening and treatment paradigms vary widely based on country income group due to disparities in resources, limited access to care, and lack of universal guidelines.
Singh T, Ichhpujani P, Singh RB, Arya S, Kumar S. Is ultra-thin Descemet stripping automated endothelial keratoplasty a viable alternative to Descemet membrane endothelial keratoplasty? A systematic review and meta-analysis. Ther Adv Ophthalmol 2023;15:25158414221147823.Abstract
BACKGROUND: Ultra-thin Descemet stripping automated endothelial keratoplasty (UT-DSAEK) is a recently developed surgical procedure that has shown promising results for the management of various corneal endothelial diseases. OBJECTIVES: To evaluate the outcomes of the UT-DSAEK to the Descemet membrane endothelial keratoplasty (DMEK). DESIGN: A systematic analysis of the studies comparing UT-DSAEK with DMEK by evaluating one or more outcomes (vision, complications, and post-operative endothelial cell counts) was performed. The meta-analysis was done if two or more studies reported a common outcome. METHODS: We used PubMed, EMBASE, and SCOPUS databases to identify articles comparing the outcomes of UT-DSAEK with DMEK and performed a meta-analysis using RevMan, version 5.4. RESULTS: A total of six studies were included in this review (two randomized clinical trials and four non-randomized comparative studies). Our analysis showed the patients who underwent DMEK cases showed better visual outcomes with a mean difference of 0.06 LogMAR (95% CI: 0.04-0.09) in BCVA, albeit with i 2 of 52% (heterogenous values). The evidence was weak, with the most weightage on retrospective studies. UT-DSAEK showed significantly fewer complications such as graft dislocations, with an odds ratio of 0.25 (95% CI: 0.13-0.48). There was no significant difference in the endothelial cell counts with a mean difference of 86.34 (95%CI: -133.09 to -305.77). CONCLUSION: Although the literature is limited on UT-DSAEK with post-operative visual acuity that could be practically at par with DMEK, lesser complication rates and comparable post-operative endothelial cells could be a suitable alternative to DMEK for corneal endothelial pathologies.
Lee HJ, Alipour F, Cruzat A, Posarelli M, Zheng L, Hamrah P. Utility of In Vivo Confocal Microscopy in Diagnosis of Acanthamoeba Keratitis: A Comparison of Patient Outcomes. Cornea 2023;42(2):135-140.Abstract
PURPOSE: The aim of this study was to compare outcomes between cases of Acanthamoeba keratitis (AK) diagnosed and treated with or without the use of in vivo confocal microscopy (IVCM). METHODS: We performed a retrospective comparative case series of 26 eyes of 23 patients diagnosed with AK at the Massachusetts Eye and Ear Infirmary over a 5-year period. The characteristics of all identified cases were summarized. We compared the time from presentation to diagnosis of AK (primary outcome), visual acuity, and rates of therapeutic penetrating keratoplasty between eyes diagnosed by culture-only group (n = 8) and by IVCM to diagnose AK (n = 9) and later confirmed by culture (IVCM/C group). RESULTS: The diagnostic delay was significantly longer in the culture only group (25 ± 29 days) compared with the IVCM/C group (3 ± 3 days, P < 0.01). At 6 months, there was a significant difference in best-corrected visual acuity between the culture-only group (1.46 ± 1.07, n = 7) and the IVCM/C group (0.22 ± 0.22, n = 8), after adjusting for initial baseline visual acuity (P = 0.02). Therapeutic penetrating keratoplasty was performed in 50% of culture-only (n = 7) and 11% of IVCM/C group eyes (n = 9), but this was not statistically significant (P = 0.13). CONCLUSIONS: IVCM can expedite the diagnosis of AK, and its use as an adjunct tool in the diagnosis of AK may result in better patient outcomes compared with basing treatment decisions on corneal cultures alone.
Maturi RK, Glassman AR, Josic K, Baker CW, Gerstenblith AT, Jampol LM, Meleth A, Martin DF, Melia M, Punjabi OS, Rofagha S, Salehi-Had H, Stockdale CR, Sun JK, Sun JK. Four-Year Visual Outcomes in the Protocol W Randomized Trial of Intravitreous Aflibercept for Prevention of Vision-Threatening Complications of Diabetic Retinopathy. JAMA 2023;329(5):376-385.Abstract
IMPORTANCE: Anti-vascular endothelial growth factor (VEGF) injections in eyes with nonproliferative diabetic retinopathy (NPDR) without center-involved diabetic macular edema (CI-DME) reduce development of vision-threatening complications from diabetes over at least 2 years, but whether this treatment has a longer-term benefit on visual acuity is unknown. OBJECTIVE: To compare the primary 4-year outcomes of visual acuity and rates of vision-threatening complications in eyes with moderate to severe NPDR treated with intravitreal aflibercept compared with sham. The primary 2-year analysis of this study has been reported. DESIGN, SETTING, AND PARTICIPANTS: Randomized clinical trial conducted at 64 clinical sites in the US and Canada from January 2016 to March 2018, enrolling 328 adults (399 eyes) with moderate to severe NPDR (Early Treatment Diabetic Retinopathy Study [ETDRS] severity level 43-53; range, 0 [worst] to 100 [best]) without CI-DME. INTERVENTIONS: Eyes were randomly assigned to 2.0 mg aflibercept (n = 200) or sham (n = 199). Eight injections were administered at defined intervals through 2 years, continuing quarterly through 4 years unless the eye improved to mild NPDR or better. Aflibercept was given in both groups to treat development of high-risk proliferative diabetic retinopathy (PDR) or CI-DME with vision loss. MAIN OUTCOMES AND MEASURES: Development of PDR or CI-DME with vision loss (≥10 letters at 1 visit or ≥5 letters at 2 consecutive visits) and change in visual acuity (best corrected ETDRS letter score) from baseline to 4 years. RESULTS: Among participants (mean age 56 years; 42.4% female; 5% Asian, 15% Black, 32% Hispanic, 45% White), the 4-year cumulative probability of developing PDR or CI-DME with vision loss was 33.9% with aflibercept vs 56.9% with sham (adjusted hazard ratio, 0.40 [97.5% CI, 0.28 to 0.57]; P < .001). The mean (SD) change in visual acuity from baseline to 4 years was -2.7 (6.5) letters with aflibercept and -2.4 (5.8) letters with sham (adjusted mean difference, -0.5 letters [97.5% CI, -2.3 to 1.3]; P = .52). Antiplatelet Trialists' Collaboration cardiovascular/cerebrovascular event rates were 9.9% (7 of 71) in bilateral participants, 10.9% (14 of 129) in unilateral aflibercept participants, and 7.8% (10 of 128) in unilateral sham participants. CONCLUSIONS AND RELEVANCE: Among patients with NPDR but without CI-DME at 4 years treatment with aflibercept vs sham, initiating aflibercept treatment only if vision-threatening complications developed, resulted in statistically significant anatomic improvement but no improvement in visual acuity. Aflibercept as a preventive strategy, as used in this trial, may not be generally warranted for patients with NPDR without CI-DME. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02634333.
Jacoba CMP, Salongcay RP, Aquino LAC, Salva CMG, Saunar AV, Alog GP, Peto T, Silva PS. Comparisons of handheld retinal imaging devices with ultrawide field images for determining diabetic retinopathy severity. Acta Ophthalmol 2023;101(6):670-678.Abstract
PURPOSE: To compare diabetic retinopathy (DR) severity identified on handheld retinal imaging with ultrawide field (UWF) images. METHODS: Mydriatic images of 225 eyes of 118 diabetic patients were prospectively imaged with the Aurora (AU) handheld retinal camera [5-field protocol (macula-centred, disc-centred, temporal, superior, inferior)] and compared with UWF images. Images were classified based on the international classification for DR. Sensitivity, specificity, kappa statistics (K/Kw) were calculated on an eye and person-level. RESULTS: Distribution of DR severity by AU/UWF images (%) by eye was no DR 41.3/36.0, mild non-proliferative DR (NPDR) 18.7/17.8, moderate 10.2/10.7, severe 16.4/15.1, proliferative DR (PDR) 13.3/20.4. Agreement between UWF and AU was exact in 64.4%, within 1-step 90.7%, k = 0.55 (95% CI:0.45-0.65), and kw = 0.79 (95% CI:0.73-0.85) by eye, and exact in 68%, within 1-step 92.9%, k = 0.58 (95% CI:0.50-0.66), and kw = 0.76 (95% CI:0.70-0.81) by person. Sensitivity/specificity for any DR, refDR, vtDR and PDR were as follows: 0.90/0.83, 0.90/0.97, 0.82/0.95 and 0.69/1.00 by person and 0.86/0.90, 0.84/0.98, 0.75/0.95 and 0.63/0.99 by eye. Handheld imaging missed 37% (17/46) eyes and 30.8% (8/26) persons with PDR. Only 3.9% (1/26) persons or 6.5% (3/46) eyes with PDR were missed if a referral threshold of moderate NPDR was used. CONCLUSIONS: Data from this study show that comparing UWF and handheld images, when PDR was the referral threshold for handheld devices, 37.0% of eyes or 30.8% of patients with PDR were missed. Due to the identification of neovascular lesions outside of the handheld fields, lower referral thresholds are needed if handheld devices are used.
Guo X, Boland MV, Swenor BK, Goldstein JE. Low Vision Rehabilitation Service Utilization Before and After Implementation of a Clinical Decision Support System in Ophthalmology. JAMA Netw Open 2023;6(2):e2254006.Abstract
IMPORTANCE: Electronic clinical decision support systems apply clinical guidelines in real time and offer a new approach to improve referral and utilization of low vision rehabilitation (LVR) care. OBJECTIVE: To characterize patients and factors associated with LVR service utilization with and without the use of an electronic health record (EHR) clinical decision support system (CDSS) alert. DESIGN, SETTING, AND PARTICIPANTS: Quality improvement study using EHR data to compare patients who did and did not utilize LVR service after referral between November 6, 2017, and October 5, 2019, (primary) and to assess overall service utilization rate from September 1, 2016, to April 2, 2021, regardless of referral status (secondary). Participants in the primary analysis were patients at a large ophthalmology department in an academic medical center in the US who received an LVR referral recommendation from their ophthalmologist according to the CDSS alert. The secondary analysis included patients with best documented visual acuity (BDVA) worse than 20/40 before, during, and after the CDSS implementation. Data were analyzed from August 2021 to April 2022. EXPOSURES: Number and locations of referral recommendations for LVR service according to the CDSS alert in the primary analysis; active CDSS implementation in the secondary analysis. MAIN OUTCOMES AND MEASURES: LVR service utilization rate was defined as the number of patients who accessed service among those who were referred (primary) and among those with BDVA worse than 20/40 (secondary). EHR data on patient demographics (age, sex, race, ethnicity) and ophthalmology encounter characteristics (numbers of referral recommendations, encounter location, and BDVA) were extracted. RESULTS: Of the 429 patients (median [IQR] age, 71 [53 to 83] years; 233 female [54%]) who received a CDSS-based referral recommendation, 184 (42.9%) utilized LVR service. Compared with nonusers of LVR, users were more likely to have received at least 2 referral recommendations (12.5% vs 6.1%; χ21 = 5.29; P = .02) and at an ophthalmology location with onsite LVR service (87.5% vs 78.0%; χ21 = 6.50; P = .01). Onsite LVR service (odds ratio, 2.06; 95% CI, 1.18-3.61) persisted as the only statistically significant factor after adjusting for patient demographics and other referral characteristics. Among patients whose BDVA was worse than 20/40 before, during, and after the CDSS implementation regardless of referral status, the LVR service utilization rate was 6.1%, 13.8%, and 7.5%, respectively. CONCLUSIONS AND RELEVANCE: In this quality improvement study, ophthalmologist referral recommendations and onsite LVR services at the location where patients receive other ophthalmic care were significantly associated with service utilization. Ophthalmology CDSSs are promising tools to apply clinical guidelines in real time to improve connection to care.
Reshef ER, Marsiglia M, Bouhadjer K, Chiou CA, O'Brien-Coon D, Reinshagen KL, Freitag SK. Reduction in Extraocular Muscle Cross-sectional Area and Correlation With Extraocular Motility and Diplopia Following Teprotumumab for Thyroid Eye Disease. Ophthalmic Plast Reconstr Surg 2023;39(5):433-439.Abstract
PURPOSE: To quantify changes in extraocular muscle (EOM) cross-sectional areas (CSA) on orbital imaging in patients with thyroid eye disease before and after teprotumumab treatment, and assess for correlation with clinical outcomes. METHODS: This retrospective study included thyroid eye disease patients treated with teprotumumab who had pre- and post-treatment CT imaging. Reformatted oblique coronal images were created for each orbit in a plane perpendicular to the optic nerve. EOM CSA measurements were performed by 2 radiographic reviewers and averaged. Primary outcomes included change in ratio of total EOM to orbit CSA, and of each individual muscle group to orbit CSA, before and after treatment. Secondary outcomes included subanalysis based on age (≥40, <40 years) and Clinical Activity Score (CAS) (≥4, <4), and comparison with clinical outcomes including CAS, Hertel exophthalmometry, Gorman diplopia score, and extraocular motility. RESULTS: Forty-eight orbits of 24 patients (16 female, mean age 57.9 years) were included. There was a significant reduction in the total EOM to orbit CSA ratio ( p < 0.01) and for each individual rectus muscle to orbit CSA ratio ( p < 0.01 for all groups). Total EOM to orbit CSA ratios were reduced for 21 patients (87.5%); this was statistically significant in 13 patients (54.2%). There was significant improvement in CAS, proptosis, diplopia, and EOM motility ( p < 0.01 for all categories). There was a significant correlation between reduction of EOM CSA, and reduction of diplopia ( p < 0.01) and EOM motility ( p < 0.01). CONCLUSIONS: EOM CSA is significantly reduced following treatment with teprotumumab, and correlates with clinical findings including improvement in extraocular motility and diplopia.
Tran JH, Stuart KV, de Vries V, Vergroesen JE, Cousins CC, Hysi PG, Do R, Rocheleau G, Kang JH, Wiggs JL, Macgregor S, Khawaja AP, Mackey DA, Klaver CCW, Ramdas WD, Pasquale LR, and for the UK Biobank Eye and Vision Consortium IGGC. Genetic Associations Between Smoking- and Glaucoma-Related Traits. Transl Vis Sci Technol 2023;12(2):20.Abstract
PURPOSE: The purpose of this study was to describe the genetic relationship between smoking and glaucoma. METHODS: We used summary-level genetic data for smoking initiation, smoking intensity (cigarettes per day [CPD]), intraocular pressure (IOP), vertical cup-disc ratio, and open-angle glaucoma (OAG) to estimate global genetic correlations (rg) and perform two-sample Mendelian randomization (MR) experiments that explored relations between traits. Finally, we examined associations between smoking genetic risk scores (GRS) and smoking traits with measured IOP and OAG in Rotterdam Study participants. RESULTS: We identified weak inverse rg between smoking- and glaucoma-related traits that were insignificant after Bonferroni correction. However, MR analysis revealed that genetically predicted smoking initiation was associated with lower IOP (-0.18 mm Hg per SD, 95% confidence interval [CI] = -0.30 to -0.06, P = 0.003). Furthermore, genetically predicted smoking intensity was associated with decreased OAG risk (odds ratio [OR] = 0.74 per SD, 95% CI = 0.61 to 0.90, P = 0.002). In the Rotterdam Study, the smoking initiation GRS was associated with lower IOP (-0.09 mm Hg per SD, 95% CI = -0.17 to -0.01, P = 0.04) and lower odds of OAG (OR = 0.84 per SD, 95% CI = 0.73 to 0.98, P = 0.02) in multivariable-adjusted analyses. In contrast, neither smoking history nor CPD was associated with IOP (P ≥ 0.38) or OAG (P ≥ 0.54). Associations between the smoking intensity GRS and glaucoma traits were null (P ≥ 0.13). CONCLUSIONS: MR experiments and GRS generated from Rotterdam Study participants support an inverse relationship between smoking and glaucoma. TRANSLATIONAL RELEVANCE: Understanding the genetic drivers of the inverse relationship between smoking and glaucoma could yield new insights into glaucoma pathophysiology.
Ghovanloo M-R, Effraim PR, Yuan J-H, Schulman BR, Jacobs DS, Dib-Hajj SD, Waxman SG. Nav1.7 P610T mutation in two siblings with persistent ocular pain after corneal axon transection: impaired slow inactivation and hyperexcitable trigeminal neurons. J Neurophysiol 2023;129(3):609-618.Abstract
Despite extensive study, the mechanisms underlying pain after axonal injury remain incompletely understood. Pain after corneal refractive surgery provides a model, in humans, of the effect of injury to trigeminal afferent nerves. Axons of trigeminal ganglion neurons that innervate the cornea are transected by laser-assisted in situ keratomileusis (LASIK). Although most patients do not experience postoperative pain, a small subgroup develop persistent ocular pain. We previously carried out genomic analysis and determined that some patients with persistent pain after axotomy of corneal axons during refractive surgery carry mutations in genes that encode the electrogenisome of trigeminal ganglion neurons, the ensemble of ion channels and receptors that regulate excitability within these cells, including SCN9A, which encodes sodium channel Nav1.7, a threshold channel abundantly expressed in sensory neurons that has been implicated in a number of pain-related disorders. Here, we describe the biophysical and electrophysiological profiling of the P610T Nav1.7 mutation found in two male siblings with persistent ocular pain after refractive surgery. Our results indicate that this mutation impairs the slow inactivation of Nav1.7. As expected from this proexcitatory change in channel function, we also demonstrate that this mutation produces increased spontaneous activity in trigeminal ganglion neurons. These findings suggest that this gain-of-function mutation in Nav1.7 may contribute to pain after injury to the axons of trigeminal ganglion neurons.NEW & NOTEWORTHY Mechanisms underlying pain after axonal injury remain elusive. A small subgroup of patients experience pain after corneal refractive surgery, providing a human pain model after well-defined injury to axons. Here we analyze a mutation (P610T) in Nav1.7, a threshold sodium channel expressed in nociceptors, found in two siblings with persistent ocular pain after refractive surgery. We show that it impairs channel slow inactivation, thereby triggering inappropriate repetitive activity in trigeminal ganglion axons that signal eye pain.

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