Subthreshold lasers operate below the threshold of visible tissue damage, thereby preventing ophthalmoscopically visible thermal damage to the chorio-retinal layers. They could represent a safe and effective alternative and/or adjunctive procedure to conventional lasers in treating diabetic macula edema (DME), central serous chorioretinopathy (CSCR), and branch retina vein occlusion (BRVO). This review focuses on the use of subthreshold micropulse laser (SMPL), its settings, and clinical applications. Despite their widespread use, a standardized protocol for sub-threshold laser settings has not been established yet, and thus, there is uncertainty in selecting effective and safe parameters for any specific situation. We conducted a comprehensive overview of the existing indications for subthreshold laser therapy and their settings for different retinal diseases. The debate revolves around which parameters could guarantee the safety of the procedure for each case, depending on the duty cycle, the laser wavelength, the spot duration, and the power, with laser power titration on one side or choosing a fixed lowered power value on the other side. SMPL therapy for DME, CSCR, and BRVO-associated macular edema has shown significant effectiveness in reducing the macular thickness, facilitating subretinal fluid absorptions, increasing the best corrected visual acuity (BCVA) and reducing the number of intravitreal injections (IVI) required annually. We presented a broad list of the laser parameters reported in the literature, organized into different tables divided based on the specific pathology, with the aim of providing a useful tool for future studies.

Background/Objectives: This study assessed the reliability of the Barrett True-K formula in patients who had undergone laser-based corneal refractive surgery by comparing outcomes using measured vs. predicted posterior corneal astigmatism (PCA) within the Barrett True-K No History formula. Methods: We selected 49 eyes out of 41 patients with a history of uncomplicated laser visual correction (LVC) that underwent cataract surgery between 2020 and 2024. The Front K1 and K2, the Back K1 and K2, the anterior chamber depth, the lens thickness, the horizontal white-to-white, and the central corneal thickness were measured using Pentacam. The axial length was measured using the IOL Master 500 or NIDEK AL-Scan. These data were then imported into the freely available online Barrett True-K calculator for post-LVC eyes, and the postoperative results were compared with the predicted IOL target. The cumulative distribution of the refractive prediction error, absolute refractive prediction error, and refractive prediction error were calculated as the difference between the postoperative spherical equivalent and the expected spherical equivalent for both the predicted and measured PCA calculations. Results: The results suggest improved accuracy with the Barrett True-K formula when incorporating measured PCA values, supporting the use of corneal tomography for optimized refractive outcomes in post-LVC cataract patients. Conclusions: It is always advisable to measure the posterior corneal surface using corneal tomography in all patients who have undergone LVC to achieve better refractive outcomes after cataract surgery.

Background/Objectives: Accurate intraocular lens (IOL) power calculation is vital for achieving the desired postoperative spherical equivalent (SE) in cataract surgery. Generative Artificial-Intelligence (AI) systems are increasingly being used in ophthalmology to refine diagnostic and surgical planning. However, it is still unknown whether a low-cost, easily accessible generative AI model like DeepSeek can match the accuracy of conventional biometric formulas. To evaluate the accuracy of DeepSeek, an open-source generative artificial intelligence (AI), in predicting postoperative refractive spherical equivalent compared to the Barrett Universal II formula in uncomplicated cataract surgeries. Methods: This study analyzed biometric data from 50 eyes of 50 patients who underwent cataract surgery between July 2024 and January 2025 at Humanitas Research Hospital in Milan, Italy. Only uncomplicated cases of emmetropia with Alcon AcrySof^® SA60WF IOL implantation were included. 30–40 days postoperative subjective refraction was measured with a calibrated trial-frame and 6 m logMAR chart by an experienced optometrist. Prediction error (PE), median absolute error (MedAE), standard deviation (SD), and cumulative frequency of PE diopters range were calculated. A Wilcoxon signed-rank test was performed to assess statistical significance. Results: Barrett showed MedAE 0.36 D [0.16–0.64] and MAE 0.43 D (95% CI, 0.34–0.52) while DeepSeek-R1 showed MedAE 0.76 D [0.52–1.01] and MAE 0.77 D (95% CI, 0.67–0.87). Cumulative accuracy (AE threshold) at ±0.25/±0.50/±0.75/±1.00/±1.25/±1.50/±1.75 D was 37.7/71.7/81.1/92.5/100.0/100.0/100.0% for Barrett Universal II and 11.1/25.9/50.0/74.1/88.9/96.3/100.0% for DeepSeek-R1 (McNemar p < 0.01 at each threshold). The paired comparison of per-eye absolute errors favored Barrett (Wilcoxon signed-rank test, p < 0.0001). Conclusions: In this cohort, Barrett Universal II outperformed DeepSeek-R1 across MedAE/MAE and cumulative accuracy thresholds, with a significant paired difference. A general-purpose generative model used off-the-shelf (fixed A-constant, no ophthalmology-specific tuning) did not match the accuracy of a validated vergence-based formula; established formulas remain the reference standard for clinical IOL power calculation.

Purpose: This review consolidates current evidence on how chronic kidney disease (CKD)-especially end-stage kidney disease (ESKD) and its treatments-alters choroidal and retinal vascular permeability, leading to changes in intraocular fluid homeostasis. Methods: A literature search of Medical Literature Analysis and Retrieval System Online (MEDLINE), reference lists, and key ophthalmology-nephrology texts was performed for studies published between 1980 and 2025. One-hundred-forty-four articles (clinical trials, observational cohorts, and case reports) met the inclusion criteria. Data were abstracted on choroidal thickness changes, blood-retinal barrier integrity, incidence of Central Serous Chororioretinopathy (CSCR) and Serous Retinal Detachment (SRD) in dialysis and transplant populations, and systemic variables such as oncotic pressure, hypertension, and corticosteroid exposure, with special attention to retinal pigment epithelium (RPE) pump function. Findings were synthesized qualitatively and tabulated where appropriate. Results: ESKD induces a triad of lowered plasma oncotic pressure, fluctuating hydrostatic forces, and impaired RPE pump function that collectively drive subretinal fluid accumulation. Hemodialysis acutely reduces sub-foveal choroidal thickness by a mean of ≈15–25 µm yet shows inconsistent effects on retinal thickness. Large population data demonstrate a three- to four-fold higher SRD risk and ~1.5-fold higher CSCR risk in dialysis patients versus controls, with peritoneal dialysis conferring the greatest hazard. After kidney transplantation, CSCR prevalence approaches 6%, driven by combined stresses of surgery, hypertension, and long-term corticosteroid or calcineurin-inhibitor therapy. Most reported SRDs resolve as systemic parameters normalize, underscoring the importance of promptly identifying systemic drivers. Conclusions: Systemic fluid-pressure imbalances and treatment-related factors in CKD significantly perturb the outer blood-retinal barrier. Regular ophthalmic surveillance, early visual-symptom screening (e.g., Amsler grid), and close nephrologist-ophthalmologist collaboration are essential for timely detection and management. Future research should quantify the relative contribution of hypoalbuminemia, hypertension, and immunosuppression to ocular permeability changes, and evaluate preventive strategies tailored to high-risk CKD subgroups.