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Purpose To report a case series of the first clinical application of a new method of astigmatic keratotomy termed full-arc, depth-dependent astigmatic keratotomy (FDAK). Methods The type of astigmatism was analyzed by corneal topography. If the astigmatism was regular, paired arcuate incisions of 90 degrees length were used. Incision depth varied between 40% and 75% of local corneal thickness for controlling the level of astigmatic correction. Results All 13 cases had regular astigmatism, and paired arcuate incisions of 90 degrees length were used. Four cases with incisions at 40% depth, five cases at 50% depth, three cases at 60% depth, and one case at 75% depth induced vector astigmatic change of 0.93 +/- 0.33 D, 1.92 +/- 0.24 D, 3.17 +/- 0.26 D, and 4.44 D, respectively, 3 months after surgery. From 3 months to 1 year or 3 years, the postoperative astigmatism was stable, and no cases showed astigmatic regression of 0.50 D or more. Every topographic difference map indicated effective flattening and steepening occurring with a 1:1 coupling ratio. All postoperative color maps showed a marked improvement in corneal sphericity. Conclusions In FDAK using paired 90 degrees incisions at 40-75% depth, an almost linear relationship between the incision depth and degree of astigmatic change was observed. FDAK may be an effective and safe method of astigmatic keratotomy that accurately controls the level of astigmatic correction. More clinical applications are necessary for drawing final conclusions and making a nomogram.

To manage posterior capsule rupture during phacoemulsification, we use a dry technique in which all procedures are performed without an irrigation/aspiration system. The dry technique is characterized by (1) continuous viscoelastic injection instead of fluid irrigation to maintain anterior chamber depth with the posterior capsule and vitreous located posteriorly and (2) static removal of most residual lens material by viscoexpression and/or manual small incision extracapsular cataract extraction without aspiration and dynamic water flow. In 16 cases of posterior capsule rupture managed using the dry technique, the residual nucleus and cortex were readily removed with minimum extension of the ruptured area and new vitreous loss. Although large amounts of viscoelastic material (mean 5.8 mL) were required, rapid and stable visual recovery was comparable to that in patients having uneventful surgery. The dry system is a safe and reliable technique for managing posterior capsule rupture during phacoemulsification.

The effects of varying the incision length and depth were analyzed using pig eyes to acquire information for realizing an ideal method of astigmatic keratotomy (AK).Single and paired arcuate incisions were made on pig corneas using a diamond knife. Incisions with varying lengths of 40 degrees, 60 degrees, and 90 degrees were made with the incision depth fixed at 90% of corneal thickness. Next, paired incisions with varying incision depth from 20% to 95% of corneal thickness were made with the incision length fixed at 90 degrees. The changes in corneal shape were analyzed using corneal topography and the degrees of astigmatic change were measured using a surgical keratometer.For short single and paired incisions (40 degrees or 60 degrees in length), narrow areas of flattenings occurred, and steepenings were observed on both sides adjacent to the flattened areas. For long paired incisions of 90 degrees length, wide areas of flattenings and steepenings were observed with an approximately 1:1 coupling ratio, and a positive linear relationship between the incision depth and degree of astigmatic change was observed in the range of incision depth between 40% and 80% of corneal thickness.This experimental study suggests that for achieving ideal corneal sphericity after AK, long incisions covering the entire steep areas (paired 90 degrees incisions for regular astigmatism) should be used and the degree of astigmatic correction may be controlled by varying the incision depth.

Purpose To evaluate the results of a modified self-sealing incision for achieving astigmatic neutrality in cataract surgery requiring a 6.0 to 7.0 mm incision as well as the methods of correcting preexisting astigmatism using these incisions. Setting Department of Ophthalmology, Kushimoto Rehabilitation Center, Kushimoto, Japan. Methods To achieve astigmatic neutrality, a frown-shaped, oblique incision—the BENT (between 9 and 12 o’clock) frown—was used. To reduce preexisting against-the-rule or with-the-rule astigmatism, the incisions were placed on the temporal or superior steep astigmatic axis, respectively. A frown incision was used when aiming for mild astigmatic reduction and an arcuate incision when aiming for relatively large astigmatic reduction. Results In the 6.0 to 7.0 mm BENT frown incision group, mean flattening was minimal throughout 6 months of follow-up, with a maximum of 0.18 diopter (D) 1 week postoperatively. Surgically induced astigmatism was less than that with other incisions. Ninety-four percent of cases had a difference in absolute astigmatism of less than 0.50 D between preoperatively and 6 months postoperatively. Relatively large flattening was observed in eyes with 6.0 to 7.0 mm steep-axis incisions of superior arcuate, temporal arcuate, superior frown, and temporal frown, with means of 1.03, 0.79, 0.64, and 0.52 D, respectively, at 6 months. Ninety-eight percent of cases had a reduction in preexisting absolute astigmatism postoperatively. Conclusion In cataract surgery using relatively large scleral self-sealing incisions, the BENT frown incision effectively achieved astigmatic neutrality. The incisions on the temporal or superior steep astigmatic axis (with selective shape) reduced astigmatism in almost all cases.

Two-handed sandwich methods of extracapsular cataract extraction using a self-sealing incision have proved difficult for many inexperienced surgeons. We developed a simpler 1-handed technique using a claw vectis-a vectis with a claw placed on its tip. When the nucleus is pulled through the scleral tunnel, it is fixed by the claw and is smoothly removed from a wound of a size comparable to that in the sandwich method. During nucleus removal, viscoelastic material is constantly injected through the irrigation vectis to maintain the anterior chamber depth, resulting in a low incidence of complications. We have performed 620 cases using the technique and found it safe and easy for both novice and experienced surgeons.

Objective The purpose of this study is to introduce and evaluate a new concept in astigmatic keratotomy (AK) named full-arc, depth-dependent AK (FDAK). Design Noncomparative interventional case series. Participants FDAK was performed on a total of 37 eyes with regular astigmatism; of these, 16 eyes received FDAK alone, and 21 eyes received FDAK combined with cataract surgery. Methods Corneal topography was used to divide the cornea into two discreet regions of “steep” and “flat.” Then, paired arcuate incisions, 90° in length, were placed along the full arc of the steep area. The level of astigmatic correction was controlled by varying the incision depth from 40% to 80% on the basis of a provisional nomogram developed by the authors. Main outcome measures Keratometries, corneal topographies, and visual acuities were measured. Results The FDAK alone group showed a significant improvement from a preoperative corneal astigmatism of 2.90 ± 0.78 diopters (D) to a postoperative value of 0.89 ± 0.52 D. The “combined” group also showed significant improvement from a preoperative corneal astigmatism of 2.97 ± 1.01 D, to a postoperative value of 1.02 ± 0.45 D. The deviation of achieved correction from attempted correction using vector analysis was between 1.37 D of undercorrection and 0.98 D of overcorrection, with 91.9% of cases within the range of ±1.0 D. Slight oblique change caused by axis deviation was observed in seven cases. Both uncorrected and corrected visual acuity showed statistically significant improvement. No serious complications were encountered. Conclusions Controlling the level of correction by varying the incision depth allowed the surgeon to use long incisions (90° in length in regular astigmatism) covering the entire steep area, minimizing the undesirable changes induced by conventional deep and narrow incision AK and resulting in an ideal corneal sphericity after surgery. FDAK enabled the surgeon to accurately control the level of astigmatic correction with minimal risk of corneal perforation.

In macaque monkeys, the age at which neurons in the primary visual cortex (V1) become sensitive to interocular image disparities, a prerequisite for stereopsis, is a matter of conjecture. To resolve this fundamental issue in binocular vision development, we measured the responsiveness of individual V1 neurons in anesthetized and paralyzed infant monkeys as a function of the relative, interocular, spatial phase of dichoptic sine-wave gratings. We found that an adult-like proportion of units were sensitive to interocular image disparity as early as the sixth postnatal day, several weeks before the onset age for stereopsis in monkeys. The ocular dominance distributions of cells in infant monkeys were also indistinguishable from those of adults. Thus, at or only a few days after birth, V1 neurons are capable of combining neural signals from the two eyes as in adults and are sensitive to interocular image disparities. However, the monocular spatial-frequency response properties of these disparity-sensitive units were immature, and their overall responsiveness was far lower than that in adults. During the first 4 postnatal weeks, both the spatial frequency response properties and the peak response amplitude rapidly improved, which resulted in a corresponding increase in the absolute sensitivity of individual units to interocular disparity. The results demonstrate that early binocular vision development in monkeys is not constrained by a paucity of disparity-sensitive V1 neurons but, instead, by the relative immaturity of the spatial response properties and the overall unresponsiveness of existing disparity-sensitive neurons.

Background Surgeons may be unaware of the ability of plant toxins to cause corneal damage. Therefore, corneal damage following intraocular surgery due to plant toxins may be misdiagnosed as postoperative infection. Case presentation A 74-year-old man presented with hyperemia and reduced visual acuity in both eyes 6 weeks after uneventful cataract surgery. We observed extensive hyperemia and corneal stromal edema with Descemet’s folds in both eyes. After obtaining a detailed patient history, we diagnosed plant toxin-induced corneal edema due to Asclepias physocarpa, which can induce corneal edema by inhibiting the Na+/K+ ATPase activity of the corneal endothelium. Antimicrobial and steroid eye drops and an oral steroid were prescribed accordingly. Symptons began to improve on day 3 and had almost completely resolved by day 6. At 1 month, the patient had fully recovered without any sequelae. Conclusion The correct diagnosis was possible in the present case as symptoms were bilateral and the patient was able to report his potential exposure to plant toxins. However, if the symptoms had been unilateral and the patient had been unaware of these toxins, he may have undergone unnecessary surgical interventions to treat non-existent postoperative endophthalmitis.