Medical hypothesis, discovery & innovation in optometry

Background: Feedback is an important component of vision therapy, providing information about visual performance and helping reinforce appropriate binocular responses. However, the frequency of different perceptual responses to commonly used vision therapy feedback techniques has not been well characterized in adults with normal binocular vision. This study aimed to determine the frequency and distribution of responses to the Small In, Large Out (SILO) and Luster vision therapy feedback techniques in a population of adults with normal ocular and binocular vision.
Methods: This cross-sectional observational study included participants with normal ocular examinations and binocular vision. A comprehensive ophthalmic and binocular vision examination was performed, including assessment of refractive error, corrected distance visual acuity (CDVA), stereoacuity, amplitude of accommodation, ocular alignment, and negative and positive fusional vergences (NFV and PFV) at distance and near. SILO feedback responses were assessed using eccentric circles and free-space fusion cards, while Luster feedback was evaluated using variable tranaglyphs (Bernell Corp., USA). SILO responses were classified as SILO, Small Out, Large In (SOLI), other responses, or no response. Luster responses were categorized as Shimmer, Half-half, Blended, Red, or Green.
Results: The study included 195 participants with a mean (standard deviation [SD]) age of 23.7 (4.3) years, 80 (41.0%) females and 115 (59.0%) males. SILO response categories differed significantly from an equal distribution (Chi-Square (3) = 96.47, P < 0.001). SOLI was the most frequently reported response (n = 106, 54.4%), followed by other responses (n = 44, 22.6%), SILO (n = 26, 13.3%), and no response (19, 9.7%). Luster response categories also differed significantly from an equal distribution (Chi-Square (4) = 73.18, P < 0.001). Half-half, Shimmer, Blended, Red, and Green responses were reported by 70 (35.9%), 66 (33.8%), 25 (12.8%), 17 (8.7%), and 17 (8.7%) participants, respectively.
Conclusions: Responses to both SILO and Luster feedback techniques varied considerably in adults with normal ocular and binocular vision, with SOLI predominating in the SILO test and Half-half and Shimmer predominating in the Luster test. These findings characterize the distribution of perceptual responses to these commonly used vision therapy techniques and provide descriptive reference data for interpreting feedback responses in similar adult populations. Future studies should investigate the reproducibility of these response patterns across diverse populations and determine their clinical relevance to vision therapy outcomes.

Background: Hydroxychloroquine (HCQ)-associated retinal toxicity may lead to irreversible visual loss, which highlights the importance of accurately characterizing retinal structural measurements in patients receiving long-term treatment. This study aimed to describe device-derived total retinal thickness (TRT) and outer retinal thickness (ORT) measurements obtained using spectral-domain optical coherence tomography (SD-OCT) in women with rheumatoid arthritis (RA) receiving HCQ and healthy female controls.
Methods: This descriptive, exploratory cross-sectional study included 64 eye records from 32 women with RA receiving HCQ and 64 eye records from 32 healthy control women. Spectral-domain optical coherence tomography was performed using the REVO FC 130 system (Optopol Technology, Poland). TRT and ORT were summarized for the central, parafoveal, and perifoveal regions of the Early Treatment Diabetic Retinopathy Study grid. The analysis was restricted to descriptive summaries, without inferential comparisons.
Results: Mean (SD) age was 46.66 (8.90) years in the HCQ-treated RA group and 46.84 (9.13) years in the control group. The corresponding mean (SD) best-corrected visual acuity was 0.04 (0.08) and 0.02 (0.06) logMAR, respectively. In the HCQ-treated RA group, the mean (SD) treatment duration, weight-adjusted daily dose, and cumulative dose were 8.22 (6.85) years, 3.74 (0.97) mg/kg/day, and 1,006.03 (977.80) g, respectively. Mean (SD) central, parafoveal-average, and perifoveal-average TRT measurements were 230.75 (19.41), 305.46 (14.16), and 268.44 (10.11) micrometre, respectively, in the HCQ-treated RA group and 235.81 (8.15), 314.68 (6.10), and 275.14 (6.78) micrometre, respectively, in the control group. The corresponding ORT measurements were 165.48 (13.51), 148.62 (8.56), and 128.21 (5.78) micrometre in the HCQ-treated RA group and 168.42 (6.77), 155.22 (2.68), and 133.00 (4.34) micrometre in the control group.
Conclusions: In this selected cross-sectional sample, descriptive eye-record summaries showed numerically lower mean TRT and ORT measurements in HCQ-treated women with RA than in healthy controls. These observations do not establish population-level differences, HCQ-specific toxicity, selective outer-retinal involvement, temporal progression, or diagnostic biomarker performance. Interpretation is limited by fellow-eye dependence, complete overlap between HCQ exposure and RA status, and the study’s selection and measurement limitations. Future longitudinal studies incorporating an appropriate RA comparison group, accounting for fellow-eye correlation, and using independently defined toxicity outcomes are needed to determine whether ORT has value in detecting early HCQ-related retinal changes.

Background: Elevated uveitis-associated intraocular pressure (IOP) may result from inflammatory, structural, and corticosteroid-related mechanisms and lead to secondary glaucoma. This study aimed to describe patients with uveitis who subsequently developed glaucoma or treatment-requiring ocular hypertension (OHT) in a tertiary referral clinic.
Methods: This retrospective study was conducted at the Uveitis Clinic of Nikookari Eye Hospital, Tabriz University of Medical Sciences. Records of patients with uveitis diagnosed or managed during the preceding 10 years were reviewed. Patients were eligible if, after uveitis onset, they had IOP > 21 mmHg documented on at least two occasions separated by at least one week and requiring intervention, or documented glaucomatous findings based on available clinical assessment. Patients with IOP elevation or glaucomatous findings predating uveitis or insufficient documentation to establish the temporal relationship were excluded. Demographic, clinical, and treatment variables were extracted.
Results: Among 441 patients with uveitis, 93 (21.1%) subsequently developed glaucoma or treatment-requiring OHT. Mean (standard deviation [SD]; range) age was 42.5 (17.4; 5–80) years, and 58 patients (62.4%) were female. Mean (SD) uveitis duration was 5.2 (4.3) years, and mean (SD) interval from uveitis diagnosis to glaucoma/OHT diagnosis was 2.1 (2.6) years. Panuveitis was the most frequent anatomical category (33.3%), followed by anterior (31.2%), intermediate (29.0%), and posterior uveitis (6.5%). Chronic uveitis was present in 76.3%, infectious uveitis in 39.8%. Herpes-family infection accounted for 14.0% of the cohort, Fuchs heterochromic iridocyclitis for 16.1%. Topical and systemic corticosteroid exposure was documented in 94.6% and 50.5%, respectively. The anterior chamber angle was open in 82.8% and closed in 17.2%. Medical, laser, and surgical treatment were documented in 95.7%, 15.1%, and 10.8%, respectively.
Conclusions: In this tertiary referral cohort, approximately one in five patients with uveitis subsequently developed glaucoma or treatment-requiring OHT. The affected population was clinically heterogeneous, with chronic and panuveitic disease, infectious etiologies, Fuchs heterochromic iridocyclitis, corticosteroid exposure, and predominantly open-angle findings. These findings support continued IOP surveillance throughout uveitis, with attention to inflammatory activity, corticosteroid exposure, angle status, and glaucomatous changes. Given the retrospective design and lack of a comparator group, these characteristics cannot be considered independent risk factors. Prospective multicenter studies are needed to clarify risk factors, clinical course, and treatment outcomes.

Background: Training school students to screen vision and communicate eye-health messages may extend the reach of community eye-care initiatives. This study assessed the screening accuracy and agreement of trained senior secondary school students relative to ophthalmologist classifications among adults in Dass, North-East Nigeria.
Methods: This community-based study evaluated screening accuracy and agreement between trained senior secondary school students and ophthalmologists among adults in Dass, North-East Nigeria, between July and September 2021. Ninety students were randomly selected from three schools and received three hours of training from two qualified ophthalmologists. Each student approached four eligible adults from their household or adjacent households through non-probability recruitment. Adults were eligible if they were aged 18 years or older and had resided locally for at least six months. Screening procedures were adapted from the World Health Organization Primary Eye Care Training Manual and comprised visual acuity testing at the 6/12 threshold and assessment of conjunctival appearance, cornea/lens appearance, eye size, and ocular alignment. Ophthalmologist classifications served as the reference standard. Sensitivity, specificity, positive and negative predictive values, overall agreement and Cohen’s kappa were calculated from five aggregate participant-level 2 × 2 tables.
Results: All 90 students participated, and 358 of 360 recruited adults were assessed (99.4%), including 234 women (65.4%). Students classified 143 adults (39.9%) as having impaired visual acuity, compared with 88 (24.6%) classified by the ophthalmologists. Visual acuity screening had 71.6% sensitivity, 70.4% specificity, 44.1% positive predictive value, and 88.4% negative predictive value, with Cohen’s kappa = 0.347. Sensitivity, specificity and kappa were 91.0%, 85.3%, and 0.701 for conjunctival assessment; 80.2%, 67.0%, and 0.377 for cornea/lens assessment; and 70.0%, 94.0%, and 0.640 for eye-size assessment, respectively. Ocular-alignment assessment had 25.0% sensitivity, 93.4% specificity, and kappa = 0.171, detecting six of 24 reference-positive classifications. Conjunctival assessment had the highest sensitivity and kappa, whereas eye-size assessment had the highest overall agreement (89.9%).
Conclusions: Screening accuracy and agreement varied substantially by task. Conjunctival assessment showed the highest sensitivity and agreement beyond chance, whereas ocular-alignment assessment missed most reference-positive findings. These findings warrant caution before wider implementation of student-led screening. Future studies should evaluate standardised training and screening procedures, retained competence, referral completion, and clinical outcomes.

Background: Fuchs uveitis syndrome (FUS) is a chronic, typically unilateral, low-grade anterior uveitis characterized by diffuse stellate keratic precipitates, iris stromal atrophy, heterochromia, cataract, and vitreous inflammation. Primary myelofibrosis (PMF) is a chronic myeloproliferative neoplasm associated predominantly with thromboembolic, hemorrhagic, and infiltrative ocular manifestations, whereas inflammatory uveitic presentations are exceedingly uncommon. We report a rare coexistence of FUS in a patient with PMF and discuss potential shared inflammatory mechanisms.
Case Presentation: A 64-year-old Asian Indian man with a 2-year history of PMF, receiving oral prednisolone and hydroxyurea, presented with a 2-month history of decreased vision in the left eye (OS). Bone marrow evaluation evidenced hypercellular marrow with megakaryocytic proliferation and reticulin fibrosis, while next-generation sequencing identified pathogenic variants involving JAK2, TET2, and SH2B3. Best-corrected distance visual acuity was 20/20 in the right eye (OD) and 20/25 in the OS, with normal intraocular pressure in both eyes. Slit-lamp examination of the OS revealed diffuse stellate keratic precipitates, minimal anterior chamber flare, iris sphincter atrophy, and grade-2 nuclear sclerosis with posterior subcapsular cataract, whereas the OD was unremarkable. No posterior synechiae or posterior segment abnormalities were identified. Based on the characteristic unilateral clinical findings, a diagnosis of FUS was established. Systemic evaluation for infectious and granulomatous causes of uveitis, including chest radiography, Mantoux testing, Treponema pallidum hemagglutination assay, and serum angiotensin-converting enzyme levels, was unremarkable. The patient was treated with topical nepafenac ophthalmic suspension and subsequently underwent uneventful phacoemulsification with posterior chamber intraocular lens implantation in the OS, achieving a postoperative visual acuity of 20/20. Over 3.5 years of follow-up, the eye remained clinically quiescent, with stable visual acuity and no evidence of recurrent inflammation or secondary glaucoma.
Conclusions: This case describes a previously unreported occurrence of FUS in a patient with PMF. Although a causal relationship cannot be established from a single case, this coexistence highlights the importance of careful ophthalmic evaluation and clinical documentation of atypical unilateral chronic anterior uveitis in patients with myeloproliferative neoplasms. Further studies are warranted to clarify the potential relationship between PMF and FUS.

Background: Central corneal thickness (CCT) can influence intraocular pressure (IOP) readings, but the relationship varies across tonometers and populations. This study examined the associations between CCT and uncorrected IOP measured using Canon TX-F non-contact tonometry (NCT) and AccuPen contact applanation tonometry in healthy young Malaysian Chinese adults.
Methods: This cross-sectional comparative study was conducted at UCSI University, Kuala Lumpur, Malaysia, between July and October 2019. Participants aged 18–25 years were recruited through voluntary, non-probability sampling. Eligibility required best-corrected visual acuity of 6/6 or better in each eye and clinically healthy anterior segments and optic nerve heads. A single optometrist performed bilateral examinations between 12:00 and 17:00 in a fixed sequence: NCT, ultrasonic pachymetry using AccuPach VI, and AccuPen tonometry. Three valid measurements per eye were averaged for each instrument. IOP readings were analysed without CCT correction.
Results: Of 98 individuals screened, 84 were enrolled, including 30 (35.7%) men and 54 (64.3%) women. Mean (standard deviation [SD]) age was 21.61 (1.88) years, and mean (SD) CCT was 570.11 (36.50) µm. Mean (SD) IOP was 15.50 (2.13) mmHg with NCT and 13.00 (2.35) mmHg with AccuPen. NCT readings were higher by a mean paired difference of 2.50 mmHg (95% confidence interval [CI], 2.11–2.89; P < 0.001). CCT was positively correlated with NCT readings (r = 0.339; 95% CI, 0.134–0.516; P < 0.05) and AccuPen readings (r = 0.310; 95% CI, 0.103–0.491; P < 0.05). CCT accounted for 11.5% and 9.6% of the variance in NCT and AccuPen readings, respectively. The regression slopes were numerically similar, corresponding to approximately 0.20 mmHg higher measured IOP per 10-µm greater CCT.
Conclusions: Greater CCT was associated with higher uncorrected IOP readings from both tonometers, while NCT yielded higher mean readings. These findings support considering CCT and instrument type when interpreting IOP in this population, without establishing device interchangeability or equivalent CCT sensitivity. Future studies in larger, more representative samples should examine how closely IOP readings from Canon TX-F NCT and AccuPen agree and how consistent repeated measurements are with each device.