Background: To record the corneal, and anterior chamber depth changes after performing recession versus resection of horizontal recti muscles.
Methods: Consecutive patients who underwent isolated lateral rectus muscle recession or resection February 2014 to January 2015 were prospectively studied. Refractive error (spherical equivalent); K1, K2, and mean k reading, anterior and posterior corneal elevation; and anterior chamber depth were measured (Pentacam) before, 1 month, and 3 months after surgery. Patients who could not maintain reliable fixation and those with a history of eye surgery were excluded. Pre- and postoperative measurements were compared by analysis of variance.
Results: A total of 36 eyes of 23 patients (average age, 16 years) were included. Rectus muscle recession was performed in 24 eyes; and resection was performed in 12 eyes. Statistically significant changes in mean keratometry of recession group only. Central anterior elevation, and central anterior chamber depth were significant when both groups are compared at first month after surgery. Changes became regressive at the end of the third month. Although a significant change of central anterior elevation persisted.
Conclusions: In recession group, the mean K was the only statistically significant variable by the first postoperative month. Comparing the both groups, the anterior corneal elevation, and central anterior chamber depth revealed a significant difference by the end of the first postoperative month. After 3 months, all parameters showed a statistical insignificant difference between the recession and resection groups except the anterior corneal elevation.
Abstract: Glaucoma is a group of eye diseases that seriously threaten human visual health. Increased intraocular pressure is the main clinical manifestation and diagnostic basis of glaucoma and is directly related to increased resistance to aqueous circulation channels. The trabecular meshwork (TM) is a multi-layer spongy tissue that filters aqueous humor. Its structure changes and the filtering capacity decreases, leading to an increase in intraocular pressure. Surgical methods for TM are constantly updated. Compared with traditional glaucoma surgical techniques, such as external trabeculectomy, the development of a new surgical technique—minimally invasive glaucoma surgery (MIGS)—enables the operation to reduce intraocular pressure efficiently while further reducing damage to the eye. MIGS achieves the purpose of surgery mainly by optimizing the TM outflow pathway, uveoscleral outflow pathway, and subconjunctival outflow pathway. A new surgical instrument, the Kahook Dual Blade, appears to optimize the TM outflow pathway in the surgical technique. The Kahook Dual Blade is a new type of angle incision instrument. Because of its unique double-edged design, in the process of goniotomy, it can effectively reduce the damage to the anterior chamber angle structure and accurately remove the appropriate amount of TM so that the aqueous humor can flow out smoothly. Kahook Dual Blade goniotomy has the advantages of avoiding complications and foreign body sensation caused by intraocular implants. The operation time is relatively short, the surgical technique is easy to master, and the TM resection scope can be determined based on the patient’s condition. It can be used to treat some clinically meaningful glaucoma. This article is organized as follows. We present the following article following the Narrative Review reporting checklist.
Abstract: Navigation technology in ophthalmology, colloquially called “eye-tracking”, has been applied to various areas of eye care. This approach encompasses motion-based navigation technology in both ophthalmic imaging and treatment. For instance, modern imaging instruments use a real-time eye-tracking system, which helps to reduce motion artefacts and increase signal-to-noise ratio in imaging acquisition such as optical coherence tomography (OCT), microperimetry, and fluorescence and color imaging. Navigation in ophthalmic surgery has been firstly applied in laser vision corrective surgery and spread to involve navigated retinal photocoagulation, and positioning guidance of intraocular lenses (IOL) during cataract surgery. It has emerged as one of the most reliable representatives of technology as it continues to transform surgical interventions into safer, more standardized, and more predictable procedures with better outcomes. Eye-tracking is essential in refractive surgery with excimer laser ablation. Using this technology for cataract surgery in patients with high preoperative astigmatism has produced better therapeutic outcomes. Navigated retinal laser has proven to be safer and more accurate compared to the use of conventional slit lamp lasers. Eye-tracking has also been used in imaging diagnostics, where it is essential for proper alignment of captured zones of interest and accurate follow-up imaging. This technology is not routinely discussed in the ophthalmic literature even though it has been truly impactful in our clinical practice and represents a small revolution in ophthalmology.
Perception is the ability to see, hear, or become aware of external stimuli through the senses. Visual stimuli are electromagnetic waves that interact with the eye and elicit a sensation. Sensations, indeed, imply the detection, resolution, and recognition of objects and images, and their accuracy depends on the integrity of the visual system. In clinical practice, evaluating the integrity of the visual system relies greatly on the assessment of visual acuity, that is to say on the capacity to identify a signal. Visual acuity, indeed, is of utmost importance for diagnosing and monitoring ophthalmological diseases. Visual acuity is a function that detects the presence of a stimulation (a signal) and resolves its detail(s). This is the case of a symbol like “E”: the stimulus is detected, then it is resolved as three horizontal bars and a vertical bar. In fact, within the clinical setting visual acuity is usually measured with alphanumeric symbols and is a three-step process that involves not only detection and resolution, but, due to the semantic content of letters and numbers, their recognition. Along with subjective (psychophysical) procedures, objective methods that do not require the active participation of the observer have been proposed to estimate visual acuity in non-collaborating subjects, malingerers, or toddlers. This paper aims to explain the psychophysical rationale underlying the measurement of visual acuity and revise the most common procedures used for its assessment.
Background: Dyop® is a dynamic optotype with a rotating and segmented visual stimulus. It can be used for visual acuity and refractive error measurement. The objective of the study was to compare refractive errormeasurement using the Dyop® acuity and LogMAR E charts.
Methods: Fifty subjects aged 18 or above with aided visual acuity better than 6/12 were recruited. Refractive error was measured by subjective refraction methods using the Dyop® acuity chart and LogMAR E charts and the duration of measurement compared. Thibo’s notation was used to represent the refractive error obtained for analysis.
Results: There was no significant difference in terms of spherical equivalent (M) (P=0.96) or J0 (P=0.78) and J45 (P=0.51) components measured using the Dyop® acuity and LogMAR E charts. However, subjective refraction measurement was significantly faster using the Dyop® acuity chart (t=4.46, P<0.05), with an average measurement time of 419.90±91.17 versus 452.04±74.71 seconds using the LogMAR E chart.
Conclusions: Accuracy of refractive error measurement using a Dyop® chart was comparable with use of a LogMAR E chart. The dynamic optotype Dyop® could be considered as an alternative fixation target to be used in subjective refraction.
Background: Spontaneously resolved primary congenital glaucoma is rare and the mechanism remains unknown. Previous literature described the phenomenon of spontaneous resolution of primary congenital glaucoma, with no further reports on follow-up visits and visual development of patients. We report a case of unilateral spontaneously resolved primary congenital glaucoma at a 7-year follow-up visit and describe the differential development of axial length (AL) between affected eye and healthy eye.
Case Description: A 6-year-old boy firstly presented at Zhongshan Ophthalmic Center with expanded corneas and ruptures in Descemet’s membranes (Haab’s striae) and apparently thin retinal nerve fiber layer (RNFL) in the left eye (LE), but normal intraocular pressure (IOP) of both eyes without anti-glaucoma medications or surgeries. At 7-year follow-up, the IOPs of bilateral eyes were stable ranging from 8 to 11 mmHg. A cup to disc ratio and the RNFL was stable in the LE at the following visit. The AL increased almost 3 mm in the right eye (RE) but 1.5 mm in the LE. Without anti-glaucoma medications or surgeries, the primary congenital glaucoma was spontaneously resolved.
Conclusions: It may figure out the development and influence of the affected eye of the patient, including AL and refraction state with regular ophthalmic examination at periodic follow-up.
Background: Surgically induced astigmatism (SIA) and corneal high-order aberrations (HOAs) are the two main causes of poor visual quality after cataract surgery. Changes in the parameters of corneal HOAs after cataract surgery and their effects on and relationships with changes in corneal curvature have not yet been reported. This study aimed to explore changes in anterior, posterior and total corneal curvature, astigmatism and HOAs after microincision cataract surgery.
Methods: Sixty-one age-related cataract patients (61 eyes) were included in this prospective study. The total, anterior and posterior corneal astigmatism and corneal HOAs were analyzed by anterior segment optical coherence tomography (AS-OCT) and iTrace before, one day, one week and three months after 2.2 mm temporal microincision coaxial phacoemulsification to evaluate the changes in anterior, posterior and total corneal curvature, astigmatism and corneal HOAs.
Results: The mean J0 and J45 values of anterior, posterior and total corneal curvature obtained by AS-OCT showed no statistically significant difference between preoperatively and any postoperative follow-up. SIA occurred on the anterior, posterior and total corneal surfaces and showed no statistically significant difference at any postoperative follow-up. No significant changes in 3rd-order oblique trefoil, vertical coma or 4th-order spherical aberrations were observed after surgery except for a significant increase in horizontal coma at postoperative day 1 (POD1).
Conclusions: There were no significant changes in corneal curvature after 2.2 mm temporal microincision coaxial phacoemulsification, and the corneal HOAs were not changed significantly except for the increase in horizontal coma at POD1, which may be one of the main reasons of poor visual quality at POD1 in some cataract patients who have good uncorrected or corrected distance vision.
