Medical hypothesis discovery and innovation in ophthalmology

Background: Nasolacrimal duct obstruction (NLDO) is characterized by epiphora and recurrent episodes of acute dacryocystitis. Despite the temporary effect of antibiotics in the acute phase, it is primarily managed by dacryocystorhinostomy (DCR). There is a new modification of external DCR that is performed without either anterior or posterior flaps. This study aimed to compare the outcomes of flapless and single-flap external DCR in adult patients with chronic symptomatic dacryocystitis secondary to NLDO.
Methods: In this retrospective, non-randomized, interventional, comparative study of patients with chronic dacryocystitis secondary to primary acquired NLDO, we compared the surgical outcomes and complication rates of flapless external DCR to those of external DCR with only anterior flap suturing. We excluded patients who declined participation and those with soft stops, nasal problems, lid margin abnormalities, lid malposition or laxity, previous lacrimal surgery, lacrimal fistula, trauma involving the lacrimal drainage system, lack of adequate follow-up, or severe septal deviation or turbinate hypertrophy. Anatomical and functional success rates were determined at the last follow-up visit and were compared. Postoperative complications were recorded and compared between groups.
Results: We included 53 patients with a male-to-female ratio of 16 (30.2%) to 37 (69.8%); 25 eyes underwent flapless DCR (group 1) and 28 eyes underwent anterior flap suturing DCR (group 2). The two groups had comparable demographic characteristics (all P > 0.05). Furthermore, anatomical (92.0% in group 1 and 92.9% in group 2) and functional (84.0% in group 1 and 92.9% in group 2) success rates at final follow-up were comparable between groups (both P > 0.05). At the one-month postoperative examination, premature tube extrusion was more often reported in group 1 (12.0%) compared to group 2 (7.1%). At the two-month follow-up examination, tube extrusion was noted in 4.0% in group 1 and 0.0% in group 2, yet the difference failed to attain statistical significance (P > 0.05).
Conclusions: We found that neither surgical method was superior in terms of anatomical or functional success rate at a maximum of one year after external DCR. Flapless DCR is a simple, effective, and reproducible alternative to the single anterior flap suturing technique for managing NLDO in adults with chronic dacryocystitis. However, further randomized clinical trials with larger sample sizes and longer follow-up periods are recommended before generalization can be justified.

Background: Myopic regression is a major complication of photorefractive keratectomy (PRK). The rates and causes vary considerably among different studies. This study aimed to investigate myopic regression at six months after myopic PRK.
Methods: In this retrospective cohort study, we included all eligible patients with myopia ranging from - 0.75 to - 9 D, aged 18 to 50 years, who underwent PRK by a single surgeon with the availability of preoperative and postoperative data at six months after the initial procedure. All participants underwent comprehensive ophthalmic examinations preoperatively and at six months post-PRK. Overcorrection was planned based on the participant’s age range to achieve the desired refractive result after PRK. All patients received the same postoperative antibiotic and steroid eye drops in a similar dosage regimen, and the contact lenses were removed after complete corneal epithelial healing. Based on the spherical equivalent of refraction six months after PRK, eyes without and with myopic regression were allocated into groups 1 and 2, respectively.
Results: We included 254 eyes of 132 patients who underwent myopic PRK with a mean (standard deviation) age of 30.12 (7.48) years; 82 (62.12%) were women and 50 (37.88%) were men. The frequency of myopic regression was significantly lower in patients with younger age, lower preoperative cylindrical refraction, and lower ablation depth (all P < 0.05). Overcorrection was more successful in eyes with low myopia than in eyes with high myopia (P < 0.05). The highest frequency of myopic regression occurred in eyes with moderate myopia (25.68%), followed by eyes with high myopia (20.0%) and low myopia (6.54%). Among different age groups, patients aged less than or equal to 30 years had a lower frequency of myopic regression. The frequency of myopic regression in the different age groups was 5.0% at 18-20 years, 7.46% at 26-30 years, 12.28% at 21-25 years, 21.31% at 31-35 years, and 26.53% at 36-50 years.
Conclusions: Overcorrection was more successful in eyes with low myopia than in eyes with high myopia. The success rate was higher in younger patients with lower astigmatism and ablation depths. Myopic regression was most frequent in eyes with moderate myopia, followed by those with high and low myopia. Further studies should replicate our findings over a longer follow-up period with a larger sample size before generalization is warranted.

Background: Wound construction is a critical step in phacoemulsification. Using anterior segment optical coherence tomography (AS-OCT), we compared the morphological features and complications of main incisions made by junior or senior residents during phacoemulsification.
Methods: This cross-sectional comparative study included eyes with senile cataracts that underwent uneventful phacoemulsification with a clear corneal incision made by seven senior and eight junior ophthalmology residents. All eyes underwent postoperative image acquisition using AS-OCT on day one and at three months, examining for morphological features and potential complications of the main incision.
Results: We included 50 eyes of 50 patients with a male-to-female ratio of 22 (44%) to 28 (56%); 26 (52%) were operated on by junior residents and 24 (48%) by seniors. The mean geometric features of the main incisions and the frequency of early and late wound complications were comparable between the two groups (all P > 0.05). A significant correlation was found between the incision length and angle with the superior (r = + 0.80; P < 0.001 and r = - 0.63; P < 0.001, respectively) and inferior (r = + 0.84; P < 0.001 and r = - 0.68; P < 0.001, respectively) areas of the incision, as well as between the length and angle of incision (r = - 0.74; P < 0.001). The number of planes in the wound architecture was not significantly different according to senior or junior resident status (P > 0.05). Although the number of eyes with stromal hydration was significantly greater for junior residents than for seniors (P < 0.001), the corneal thickness at the entrance to the cornea or the anterior chamber, presence of endothelial wound gaping, and Descemet’s membrane detachment were comparable between eyes with and without stromal hydration (all P > 0.05). At three months, 29 (58%) patients returned for examination, in whom seven (24%) had late wound complications.
Conclusions: This study found no significant differences in the performances of junior and senior residents in terms of wound construction or its associated complications. However, considering the overall rate of some observed wound-related complications, we recommended revision of the resident educational curriculum concerning the structure and complications of the main incision.

Background: In non-glaucomatous eyes, many factors impact intraocular pressure (IOP) reduction following phacoemulsification. This study aimed to determine the relationship between changes in IOP and alterations in anterior chamber biometric measurements using the Pentacam Scheimpflug anterior segment imaging system before and after uneventful phacoemulsification in non-glaucomatous eyes.
Methods: This prospective interventional study included patients with ages of 20 – 80 years, no known systemic diseases, and visually significant cataracts necessitating phacoemulsification with posterior chamber intraocular lens implantation. The preoperative and two-month postoperative IOPs were measured using a Goldmann applanation tonometer, and the iridocorneal angle (ICA) in four quadrants (superior, inferior, nasal, and temporal), anterior chamber depth (ACD), and anterior chamber volume (ACV) were measured using the Pentacam.
Results: Forty-two eyes of 42 patients with a mean (standard deviation [SD]) age of 56.8 (10.7) years were included; 22 (52%) were men and 20 (48%) were women. The eyes demonstrated statistically significant changes in postoperative IOP, ACD, ACV, and in widening of the ICA (all P < 0.05), with a mean (SD) IOP reduction of 4.5 (2.7) mmHg, ACD deepening of 0.7 (0.6) mm, ACV increase of 33.2 (21.1) mm3, and ICA widening of 7.5o (6.4o), 12.4o (7.7o), 9.1o (7.1o), and 11.5o (6.1o) in the superior, inferior, temporal, and nasal quadrants, respectively. A significant positive correlation was detected between pre- and postoperative IOP (r = + 0.58; P < 0.001) and between pre- and postoperative ACD (r = + 0.50; P < 0.001). Significant negative correlations were detected between preoperative ACV and changes in ACV (r = - 0.42; P < 0.001) and between preoperative ICA and changes in ICA (r = - 0.02; P = 0.001). However, no significant correlations were observed between the changes in IOP and patient age (r = + 0.001; P = 0.957) and axial length of the eye (r = + 0.13; P = 0.221), or changes in ICA (r = - 0.01; P = 0.945), ACD (r = + 0.01; P = 0.945), and ACV (r = - 0.12; P = 0.599).
Conclusions: We observed a significant reduction in IOP, widening of the ICA, and increases in ACD and ACV after phacoemulsification; however, there was no significant correlation between changes in IOP and other biometric variables. Further studies are required to determine the exact mechanisms underlying these effects.

Background: Implantation of multifocal intraocular lenses (IOLs) is becoming increasingly popular for the treatment of visual demands at various distances in patients undergoing phacoemulsification cataract surgery. We aimed to assess the visual performance and rates of photic phenomena, posterior capsule opacification (PCO), and spectacle independence in patients with bilateral implantation of the AcrySof® IQ PanOptix® multifocal IOL model TFNT00 at one and six months postoperatively.
Methods: This prospective interventional cohort study included adult patients who underwent uneventful phacoemulsification cataract surgery with bilateral implantation of AcrySof® IQ PanOptix® IOL. Uncorrected and corrected visual acuities at far, intermediate, and near distances were measured preoperatively and at the one- and six-month postoperative follow-up examinations. The rates of photic phenomena, postoperative need for near and distance spectacles, and PCO were also recorded.
Results: We included 164 eyes of 82 patients with a male-to-female ratio of 38 (46.3%) to 44 (53.7%) and a mean (standard deviation [SD]) age of 52.37 (7.62) years. There were statistically significant improvements in the visual acuities of both eyes across all distances at the one- and six-month follow-up examinations compared to the preoperative values (all P < 0.001), except for corrected near visual acuity in the right eye (P > 0.05) at six-month. We also detected significant postoperative improvements in visual acuities of both eyes across all distances at the six-month follow-up compared to values at the one-month follow-up (all P < 0.05), except for corrected near visual acuity in the right eye (P > 0.05). The photic phenomenon was reported by 12 (14.6%) of the 82 patients at the six-month postoperative follow-up. Five (6.1%) and eight (9.8%) of the 82 patients reported using spectacles for distance and near, respectively. Additionally, PCO developed in 19 (11.6%) of the 164 included eyes, although it was not clinically significant at six months.
Conclusions: The AcrySof® IQ PanOptix® IOL model TFNT00 is recommended for use, given its excellent performance in all ranges of vision, a high rate of spectacle independence, and a good safety profile. Future comparative studies with longer follow-up periods are warranted to verify superiority of its performance over that of other available multifocal IOLs.

Background: Keen vision is one of the most important qualities required of athletes. It enables players to perform sports-related drills and apply decision-making skills. To accurately measure the visual ability of athletes, it is important to first identify the variety of visual skills involved in the particular sport. The objectives of this novel review are to identify the most important visual skills required for rugby, and to create a reference point for further studies to include visual skills essential to rugby players.
Methods: We conducted an electronic search with various combinations of relevant keywords using the following databases: Sport Discuss, Ovid’s Evidence-Based Medicine Reviews, PubMed/MEDLINE, Current Contents, Science Direct, the National Research Council’s Canada Institute for Scientific and Technical Information, Cochrane Database of Systematic Reviews, Google Scholar, and international electronic catalogues to assess the scientific literature related to the visual skills required for rugby. Only the articles published in English were included. We extracted data on the relationship between vision and match performance, the defined problem or purpose of the study, and the inclusion of theoretical definitions of tactical behaviors.
Results: Our search yielded 80 records, 51 of which fulfilled the inclusion criteria. The most important visual skills in rugby are classified based on whether they meet the requirements for visual hardware or visual software skills. Visual hardware skills include visual acuity, depth perception, fusion flexibility, and contrast sensitivity; visual software skills include eye tracking, hand-eye coordination, eye focusing, peripheral vision, speed and span of recognition, visual response time, and visual memory.
Conclusions: Rugby players must use both visual hardware and software skills to reliably observe their teammates’ positions, understand their opponents’ actions and tactics, handle the ball, analyze the immediate circumstances, and anticipate what will occur. Further studies are needed to verify the significance of each visual skill in actual competition to determine a relationship between vision and the results of a championship.