Medical Hypothesis, Discovery, and Innovation in Ophthalmology最新文献

Background: Linear-regression analysis is a well-known statistical technique that serves as a basis for understanding the relationships between variables. Its simplicity and interpretability render it the preferred choice in healthcare research, including vision science, as it enables researchers and practitioners to model and predict outcomes effectively. This article presents the fundamentals of linear-regression modeling and reviews the applications and interpretations of the main linear-regression analysis.

Methods: The primary objective of linear regression is to fit a linear equation to observed data, thus allowing one to predict and interpret the effects of predictor variables. A simple linear regression involves a single independent variable, whereas multiple linear regression includes multiple predictors. A linear-regression model is used to identify the general underlying pattern connecting independent and dependent variables, prove the relationship between these variables, and predict the dependent variables for a specified value of the independent variables. This review demonstrates the appropriate interpretation of linear-regression results using examples from publications in the field of vision science.

Results: Simple and multiple linear regressions are performed, with emphasis on the correct interpretation of standardized and unstandardized regression coefficients, the coefficient of determination, the method for variable selection, assumptions in linear regression, dummy variables, and sample size, along with common mistakes in reporting linear-regression analysis. Finally, a checklist is presented to the editors and peer reviewers for a systematic assessment of submissions that used linear-regression models.

Conclusions: Medical practitioners and researchers should acquire basic knowledge of linear-regression such that they can contribute meaningfully to the development of technology by accurately interpreting research outcomes. Incorrect use or interpretation of appropriate linear-regression models may result in inaccurate results. Appointing an expert statistician in an interdisciplinary research team may offer added value to the study design by preventing overstated results.

Background: Age-related macular degeneration (ARMD) leads to impaired vision and potential blindness. Globally, it accounts for approximately 9% of vision loss cases, and a projected 288 million individuals will be affected by 2040. Current treatments have limitations such as variable effectiveness, high costs, and potential side effects. Additionally, atrophic ARMD management remains challenging. As saffron has shown promising neuroprotective and antioxidant effects by potentially delaying disease progression, this study aims to review the mechanistic, pre-clinical, and clinical evidence of the effects, safety, and tolerability of saffron in ARMD treatment.

Methods: The Scale for the Assessment of Narrative Review Articles was applied in this narrative review. To find relevant literature, the syntax "(saffron OR crocus) AND (retin* OR "geographic atrophy" OR "choroidal neovascular*" OR "macular degeneration")" was searched in PubMed/MEDLINE. Pre-clinical and clinical original investigations of the effects of saffron in ARMD along with the eligible studies cited in their reference lists were identified and included.

Results: Saffron and its active compounds, crocin and crocetin, have shown promising results in improving visual function and delaying ARMD progression. Several clinical studies have found that daily supplementation with 20-50 mg of saffron or 5-15 mg of crocin for 3-12 months significantly improved best-corrected visual acuity, contrast sensitivity, and retinal function as measured by electroretinogram and microperimetry, with benefits observed in both dry and wet forms of ARMD. The effects were independent of genetic risk factors and maintained during the follow-up periods, suggesting the potential role of saffron as a long-term treatment option. Saffron reduces ARMD progression via anti-angiogenic, neuroprotective, and antioxidant mechanisms. Moreover, saffron is safe and well tolerated.

Conclusions: Although further research is needed to confirm long-term safety and efficacy, current evidence supports the use of saffron or crocin supplements as a safe and tolerable adjunct therapy for ARMD management.

Background: The association between keratoconus and thyroid gland dysfunction (TGD) remains controversial. We aimed to determine the frequency of keratoconus among patients with laboratory-confirmed, treatment-naive TGD compared with that of age- and sex-matched healthy controls. Moreover, we investigated the potential relationship between TGD and corneal topographic and tomographic parameters.

Methods: This multicenter, cross-sectional study recruited individuals with treatment-naive, laboratory-confirmed TGD and sex- and age-matched healthy controls. Demographic and ophthalmic data of all participants were recorded. All participants underwent comprehensive ocular examinations and corneal tomography. Patterns of symmetric bowtie, asymmetric bowtie, asymmetric bowtie/superior steep, asymmetric bowtie/inferior steep, or asymmetric bowtie pattern with a skewed radial axis were documented if present. Furthermore, the maximum simulated keratometry value (Kmax), corneal thinnest thickness (CTT), and back elevation (BE) values were recorded. We measured the serum concentrations of thyroid-stimulating hormone (TSH) and thyroid hormones (free thyroxine [FT4] and free tri-iodothyronine [FT3]) using an immunoassay method.

Results: We included 200 eyes of 200 individuals with TGD and 200 eyes of 200 healthy age- and sex-matched controls, with female predominance in both groups. The mean FT4 concentration was significantly higher and the TSH concentration was significantly lower in the TGD group than in the control group (both P < 0.0001), whereas the FT3 level was comparable between groups (P > 0.05). In the TGD group, the frequencies of hyperthyroidism and hypothyroidism were 190 (95%) and 10 (5%), respectively. We found significantly lower mean CTT, higher Kmax, and greater BE values with a significantly higher frequency of abnormal topographic patterns among eyes in the TGD group than in controls (all P < 0.05). The frequency of eyes with keratoconus was significantly higher in the TGD (7.5%) group than in the control (0.5%) group (P < 0.0001). Except for a statistically significant correlation of Kmax (r = - 0.23, P < 0.05) and CTT (r = + 0.15, P < 0.05) with TSH level in the TGD group, no significant correlation was found between corneal characteristics and thyroid profile in either group (all P > 0.05).

Conclusions: We observed a higher frequency of keratoconus, with female predominance, in the TGD group. TGD was associated with significant changes in certain corneal topographic and tomographic parameters. Compared with healthy controls, individuals with TGD demonstrated increased Kmax and BE values with more corneal thinning, highlighting the potential association between keratoconus and TGD. However, further large-scale longitudinal studies are essential to confirm our findings.

Background: Astigmatism is the most prevalent refractive error among children and adults, and it can lead to visual impairment if left uncorrected. The management of compound hyperopic astigmatism is more challenging. This study presents the 12-month outcomes of toric implantable collamer lens (ICL) implantation in eyes with hyperopic astigmatism.

Methods: This interventional case series included patients with simple or compound hyperopic astigmatism who underwent toric ICL implantation. All eligible individuals underwent a detailed ocular examination. Uncorrected and corrected distance visual acuities (UDVA and CDVA, respectively), intraocular pressure, and manifest and cycloplegic refraction results were documented. Pentacam corneal tomography was performed to assess the central corneal thickness, iridocorneal angle width, and anterior chamber depth. Endothelioscopy was performed to determine endothelial cell density. The ICL V4b model was implanted in all the included eyes. Safety and efficacy indices were calculated as postoperative CDVA/preoperative CDVA and postoperative UDVA/preoperative CDVA, respectively.

Results: Twenty-six eyes with low-grade simple or compound hyperopic astigmatism were included. All eyes experienced a significant improvement of four lines in postoperative UDVA (P < 0.001), and their postoperative CDVA remained stable at the 12-month follow-up (P > 0.05). The safety and efficacy indices were 1.0. None of the eyes lost two or more lines of CDVA; in 81% of the eyes, CDVA was unchanged, and the proportion of eyes with 20/30 or better postoperative UDVA was identical to that with 20/30 or better preoperative CDVA (81% for each). The mean manifest spherical equivalent at the 12-month postoperative visit had significantly improved (P < 0.001). The percentages of eyes with postoperative spherical equivalent within ± 0.50 D and ± 1.00 D were 81% and 96%, respectively. The postoperative refractive cylinder improved significantly (P < 0.05), and the percentage of eyes with refractive cylinder within ± 0.50 DC and ± 1.00 DC were 50% and 77%, respectively.

Conclusions: Our outcomes indicate that toric ICL implantation is safe and effective for managing low-grade simple or compound hyperopic astigmatism. The proportion of eyes with 20/30 or better postoperative UDVA was identical to that with a 20/30 or better preoperative CDVA. The manifest spherical equivalent and refractive cylinder were significantly reduced. No serious safety concerns were observed. Further prospective large-scale studies with a wide range of ages and grades of hyperopic astigmatism are required to verify these preliminary outcomes.

Background: The intraretinal hyperreflective line (IHL) is a novel posterior segment finding demonstrable using careful optical coherence tomography (OCT) examination. It likely indicates a reaction against photoreceptor, Muller cell, and/or retinal pigment epithelial damage. This study analyzed the spectral-domain OCT characteristics of IHLs to disclose their presence in various retinal conditions.

Methods: A retrospective review of the charted and imaging records of participants with IHL was conducted at Dokuz Eylul University Department of Ophthalmology between January 2019 and August 2023. The inclusion criterion was the detection of an IHL on good-quality B-scan spectral-domain OCT. An IHL was defined as a vertical line extending from the ellipsoid zone band (or lower) through the outer nuclear layer to the internal limiting membrane in the central fovea. Associated retinal conditions were recorded as potential causative factors for the presence of IHL.

Results: IHL was observed on spectral-domain OCT in 40 eyes of 38 participants with several retinal diseases assessment. Fourteen eyes (35%) underwent vitreoretinal surgery pre-IHL detection (12 were operated for full-thickness macular hole [FTMH], one for epiretinal membrane [ERM], and one for rhegmatogenous retinal detachment). In six eyes (15%) a microhole coexisted. Four eyes (10%) had a concurrent lamellar macular hole. The IHL preceded the occurrence of FTMH in three eyes (7.5%), and diabetic macular edema and type 2 idiopathic macular telangiectasia (MacTel-2) were present in three eyes (7.5%) each. The remaining conditions included vitreomacular traction (VMT), nonarteritic anterior ischemic optic neuropathy with central retinal artery occlusion, commotio retinae, exudative age-related macular degeneration, ERM, non-infectious idiopathic posterior uveitis, and Coats' disease, each affecting one eye (2.5%). Of the two participants with bilateral involvement, one was diagnosed with MacTel-2 and the other had IHL with VMT in the right eye that was detected post-vitreoretinal surgery for FTMH in the left eye.

Conclusions: Although IHLs are mostly identified in eyes with vitreomacular surface diseases, clinicians may encounter IHLs in other types of retinal pathology. Further large-scale, multicenter, long-term studies on the presence of IHLs in OCT imaging are required to provide more substantial insight on this biomarker.

Background: Panretinal photocoagulation (PRP) impacts macular function in eyes with early proliferative diabetic retinopathy (PDR). Herein, we used the multifocal electroretinogram (mfERG) to objectively investigate this concept.

Methods: In this prospective interventional case series, we enrolled patients with treatment-naive early PDR, absence of clinically significant macular edema, and requirement for PRP. All participants underwent detailed ocular examinations. We measured the best-corrected distance visual acuity (BCDVA), conducted optical coherence tomography imaging to measure central macular thickness (CMT), and performed mfERG at baseline and 3 months post-PRP. Amplitude and latency of the mfERG response were evaluated within the innermost four of the five concentric rings.

Results: We enrolled 29 eyes of 23 patients with a mean (standard deviation) age of 54.3 (8.8) years and male-to-female ratio of 1:1.3. The mean BCDVA was unchanged post-treatment (P > 0.05), and the BCDVA in 26 eyes (89.7%) was either improved or unchanged, whereas in three eyes (10.3%) it decreased. The mean CMT was unchanged post-PRP (P > 0.05). Concerning the mfERG, the mean P1 amplitudes decreased significantly in all four concentric rings from the foveola at 3 months post-PRP compared with baseline values (all P < 0.05); however, the latencies were unchanged (all P > 0.05). At baseline, BCDVA correlated significantly with both the amplitude (r = + 0.55; P < 0.05) and latency (r = - 0.38; P < 0.05) of the mfERG in the central ring, whereas a significant correlation was detected with only the amplitude at 3 months post-PRP (r = + 0.52; P < 0.05).

Conclusions: Macular function was decreased 3 months post-PRP in patients with early PDR, as indicated by decreased amplitude of the mfERG, whereas the functional and anatomical parameters were stable. The mfERG served as an objective tool for measuring retinal function and predicting visual outcomes post-PRP in eyes with early PDR. A higher amplitude in the mfERG correlated substantially with a better visual outcome post-PRP. Further multi-center longitudinal studies with robust designs including different PDR severity levels may reveal additional objective after-effects of PRP.

Background: The effects of trabeculectomy on anterior segment parameters have been widely investigated. However, the stabilization time for various glaucoma types after trabeculectomy remains debatable. We investigated the effect of mitomycin C-augmented trabeculectomy on ocular anterior segment parameters in primary open-angle glaucoma (POAG) and pseudoexfoliation glaucoma (PXG) during short-term follow-up using the Pentacam HR.

Methods: In this retrospective observational study, consecutive patients diagnosed with medically uncontrolled POAG or PXG who underwent MMC-augmented trabeculectomy were recruited. All individuals underwent detailed ocular examinations. All trabeculectomies were performed by a single surgeon using the same technique. Anterior segment parameters, including anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), and central corneal thickness (CCT) were measured using the Pentacam HR, along with intraocular pressure (IOP) using a Goldmann applanation tonometer, pre-operatively and at 1-week, 1-month, and 3-month post-operative visits.

Results: We included 80 patients with a median (range) age of 58.0 (41.0-86.0) years having a nearly similar sex ratio. The study groups were matched according to sex and age (both P > 0.05). The group-by-time interaction was significant for CCT and ACV (both P < 0.05) but not for IOP, ACD, and ACA (all P > 0.05). The mean (standard deviation [SD]) IOP, ACD, and ACA were comparable between groups (all P > 0.05) during the 3-month period; however, they changed significantly over time in both groups (all P < 0.001). The mean CCT and ACV were comparable between groups at each time point (all P > 0.05), except at the 1-month post-operative visit, at which the mean (SD) ACV was significantly lower in the PXG group (P < 0.05). We found a comparable mean (SD) CCT between paired visits in each group (all P > 0.05), except for the mean (SD) CCT at 3 months, which was significantly lower than that at the 1-month post-operative visit in the PXG group (P < 0.05). We found a comparable mean (SD) ACV between paired visits in each group (all P > 0.05); however, it was significantly lower at the 1-month post-operative versus the baseline visit in both groups and resumed a significantly higher value at the 1-month versus the 1-week visit and at the 3-month versus the 1-month visit in the PXG group (all P < 0.05).

Conclusions: We observed significant changes in IOP, ACD, and ACA over 3 months after post-augmented trabeculectomy in eyes with POAG and PXG; however, the majority of anterior segment parameters were comparable between the two groups. Further large-scale studies with longer follow-up periods should be conducted to verify the post-operative fluctuations in these parameters in POAG and PXG.

Background: Monotherapy, age, and side effects are significant risk factors for the discontinuation of antiglaucoma therapy. Long-term therapy persistence is crucial for slowing disease progression and preventing irreversible blindness. Therefore, it is essential to identify patients at higher risk of discontinuation. In this study, we aimed to evaluate the real-world persistence of antiglaucoma therapy in patients diagnosed with glaucoma in the primary healthcare units of the Lisbon and Tagus Valley regions.

Methods: We conducted a retrospective longitudinal study by collecting data from the prescription records of new antiglaucoma drug users diagnosed with glaucoma between 2012 and 2013 in the Primary Health Care Units of the Lisbon and Tagus Valley Region. These patients were followed over 3 years. Therapy persistence was measured as the proportion of patients remaining on any antiglaucoma drug, regardless of any modifications or switching of drugs over time. Persistence was assessed at three time points: the end of the first, second, and third years of the observation period.

Results: A total of 2138 patients treated using new antiglaucoma drugs (867 [40.6%] male patients; 1271 [59.4%] female patients) were included in the study. Over the observation period, the overall persistence rate decreased from 91.9% (n = 1965) in the first year to 67.3% (n = 1439) in the third year. Older patients (≥ 65 years) showed higher persistence rates, although there was a decrease over the 3-year follow-up period (from 1481 [92.7%] to 1124 [70.4%]). Additionally, participants initially treated with monotherapy showed higher persistence rates, ranging from 92.4% (n = 1186) in the first year to 70.2% (n = 901) in the third year.

Conclusions: The findings highlight the importance of patient follow-up over time, as almost one in three new antiglaucoma therapy users completely discontinued treatment, potentially risking disease progression. This could be mitigated with proper use of these drugs. Further studies should utilize recent health information systems to explore the impact of medication adherence and persistence on the functional and structural outcomes in patients with glaucoma.

Background: Pseudoexfoliation syndrome (PES) is an age-related systemic condition that predominantly affects ocular structures and is characterized by the deposition of material on the lens, ciliary body, zonules, corneal endothelium, iris, and pupillary margin. We compared the corneal endothelial morphology, anterior segment parameters, corneal densitometry, and corneal topographic characteristics between the clinically affected and apparently normal fellow eyes of patients with clinically unilateral PES.

Methods: This was a comparative, cross-sectional study of 34 patients with clinically unilateral PES. The anterior segment was examined using a Scheimpflug imaging system, and the corneal endothelium was assessed using a noncontact specular microscope. Corneal endothelial cell density, polymegathism, and pleomorphism were assessed using the specular microscope. Furthermore, the Scheimpflug camera was used to measure the corneal power of the flat and steep axis, mean corneal power, maximum keratometry, anterior chamber angle, anterior chamber depth, anterior chamber volume, corneal volume, and the corneal thickness at the apex point, center of the pupil, and the thinnest point. Corneal densitometry was evaluated at two concentric zones (0-2 mm and 0-12 mm).

Results: In total, 68 eyes from 34 patients were ultimately included in the study. The mean (standard deviation) age of the patients was 73.38 (8.75) years (range: 50-87 years). Among the included patients, 17 (50%) were male and 17 (50%) were female. The anterior segment parameters did not significantly differ between eyes with PES and their clinically unaffected fellow eyes (all P > 0.05). Similarly, no statistically significant difference was observed in corneal endothelial morphology (all P > 0.05).

Conclusions: Our measured parameters do not differ between the clinically affected eye and the clinically unaffected fellow eye. This supports the theory that PES is a bilateral disorder. Considering the variety of complications associated with PES, bilateral involvement should be assumed in the clinical and surgical management of patients with clinically unilateral PES. In the future, new research could increase our understanding of this syndrome.

Background: Strengthening of extraocular muscles is a conventional procedure in the management of strabismus. Plication may be an alternative strengthening technique, and is less invasive than resection. This study compared plication and resection, each combined with antagonist muscle recession, in terms of success rates and changes in ocular deviation in the management of horizontal strabismus.

Methods: This retrospective study recruited individuals with horizontal strabismus who underwent plication (group I) or resection (group II) coupled with antagonist muscle recession. All participants underwent a detailed baseline eye and ocular motility evaluation. Demographic and clinical data were collected, including age, sex, type of preoperative strabismus (exotropia or esotropia), baseline visual acuity, mean follow-up duration, laterality of operated eye, surgical doses of correction (resection, plication, or recession) in millimeters, preoperative strabismus magnitude in prism diopters (PD), and postoperative strabismus magnitude in PD. Successful postoperative deviation was defined as ≤10 PD. At final follow-up, the success rates and degrees of change in angle of deviation were recorded.

Results: Forty-four patients were enrolled: 19 patients in group I (plication) and 25 patients in group II (resection). The groups had comparable ages, sex ratios, types of strabismus, and preoperative and postoperative angles of deviation (all P > 0.05). Despite comparable success rates between groups (73.7% in group I versus 64.0% in group II, P > 0.05), the difference (9.7%) was marginally close to the predefined clinically meaningful difference of 10%. In the esotropia subgroup, despite comparable alignment between the plication and resection groups (P > 0.05), the difference was clinically meaningful (17.3%), and both groups had higher success rates in the esotropia subtype than in the exotropia subtype. The rate of over- or undercorrection was not statistically or clinically different in the total and in each subtype of strabismus (all P > 0.05). Success rates for unilateral and bilateral cases were similar between groups (both P > 0.05). Changes in angle of deviation were similar for individuals with esotropia and exotropia between groups (both P > 0.05).

Conclusions: In esotropic and exotropic strabismus, plication and resection procedures combined with antagonist recession were similarly effective. However, further randomized, large-scale, longitudinal studies with clinical and subjective evaluations could comitant strabismus, squint, esotropias, primary exotropia, exodeviation, plication, resection, recession, amblyopias.