Corneal Incision Architecture Research Articles

Comparison of Postoperative Corneal Astigmatism Induced by Two Different Corneal Incisions during Microincisional Cataract Surgery.

Objectives:Clear corneal incision (CCI) architecture in modern microincision cataract surgery (MICS) plays an undeniable role in postoperative refraction. The goal of this study was to evaluate the effect of hinge incision prior to two-step CCI on postoperative refractive astigmatism after cataract surgery and to demonstrate the schematic presentation of these postoperative astigmatic changes via double-angle polar plots.Methods:This study involved a consecutive case series of patients who had MICS. The first incision was performed as a two-step CCI, whereas the second was made as a hinge incision prior to 2-step CCI. The preoperative corneal and postoperative refractive astigmatism and surgically induced astigmatism (SIA) were calculated by vectorial analysis. Hotelling’s T2 test was performed to compare the centroid values of preoperative and postoperative corneal astigmatism.Results:A total of 63 eyes from 57 subjects were evaluated. Group I consisted of 27 eyes with the two-step CCI, and Group II included 36 eyes with the hinge incision prior to two-step CCI. No significant difference was found between the groups in terms of age, sex, axial length, keratometry readings, implanted intraocular lens power, and postoperative spherical equivalent. The centroids of corneal astigmatism postoperatively increased to 0.21 D at 87.6°±0.61 with no significance in Group I (p=0.525) and to 0.70 D at 90.6°±0.47 with significance in Group II (p=0.032). The difference in postoperative centroids between the two groups was also significantly different (p=0.043). Finally, the centroids of SIA were 0.12 D at 85.5°±0.50 and 0.22 D at 91.1°±0.49 for Group I and Group II, respectively, with no significance.Conclusion:A hinge incision did not have an unfavorable effect on postoperative refractive astigmatism; therefore, it may be preferred for controlled entrance to the anterior chamber.

Effect of manual, preloaded, and automated preloaded injectors on corneal incision architecture after IOL implantation.

To analyze the effects on corneal morphology of manual, preloaded, and automated preloaded intraocular lens (IOL) injectors in eye bank human corneas by environmental scanning electron microscopy (ESEM) and in patients after phacoemulsification using anterior segment optical coherence tomography (AS-OCT). Eye Clinic, Careggi University Hospital, Florence, Italy. Retrospective and experimental study. Seventy-eight corneal incisions were examined after IOL implantation: 30 in human corneas mounted on an artificial chamber using ESEM (ex vivo); 48 in patients undergoing phacoemulsification (in vivo). Three different injectors were used for both analyses: manual (Monarch III, n = 26), manual preloaded (UltraSert, n = 26), and automated preloaded system (AutonoMe, n = 26). Thirty IOLs were implanted in the ex vivo study: 5 intermediate and 5 high dioptric powers for AcrySof IQ (Monarch and UltraSert) and for Clareon (AutonoMe) IOLs. In the in vivo analysis, 16 corneal wounds for each injector were evaluated using AS-OCT; in the ex vivo study, incision width was measured and Descemet membrane detachment, posterior wound retraction, and posterior gape were analyzed. In the eye bank corneas, the incision width was significantly wider in the high dioptric power IOL manual subgroup (P < .05), with more Descemet tearing compared with AutonoMe. In the in vivo study, the incidence of Descemet membrane detachment, posterior gape, and wound retraction was lower in the automated preloaded group at 1 postoperative day 1. The automated preloaded injector ensured less trauma to the wound and contributed to preserving the endothelial side of the incision even during the implantation of high-power IOLs and in the early postoperative period.

Intraoperative Optical Coherence Tomography Analysis of Clear Corneal Incision: Effect of the Lateral Stromal Hydration.

Methods The cohort included 65 clear corneal incisions of 49 patients who underwent cataract surgery. Corneal incisions were recorded using a Leica Proveo 8 microscope with an intraoperative OCT EnFocus™ device continuously during the surgery. Corneal incision morphology before and after lateral stromal hydration was analysed. Results Good adaptation of the corneal incision before hydration was present in 39 cases (60%), in 16 cases (24.6%), the prominence of posterior lip was present, and, in 10 cases (15.4%), the posterior lip tongue was inverted/retracted into the incision. In 38 cases (58.5%), hydration had no effect on the incision architecture; most often, it was primarily a well-adapted corneal incision (46.2%), less often an incision with posterior lip prominence (10.8%), or tongue inversion into the incision (1.6%) prior to hydration. Hydration worsened the incision architecture in 14 cases (21.5%); most often, it induced/worsened posterior lip prominence (15.4%), less often posterior lip retraction (1.6%), tongue inversion into the incision (1.6%), gap development in the peripheral part of the corneal incision (1.6%), or incomplete opening of the corneal incision (1.6%). In 13 cases (20%), hydration improved the incision architecture, especially in cases with inverted or retracted posterior lip tongue (12.3%), less often in cases with posterior lip prominence (7.7%). Conclusion Lateral stromal hydration seldom affects the condition of the corneal incision. Still, it can cause both deterioration and improvement of the corneal incision architecture. Intraoperative OCT provides real-time monitoring of corneal incision morphology during hydration procedure.

Variations in intraocular lens injector dimensions and corneal incision architecture after cataract surgery

To evaluate the differences in intraocular lens (IOL) injectors and to assess the effect of IOL insertion on injector tips and eyes after cataract surgery in a rabbit model. Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, USA. Experimental study. A modified optical comparator was used to measure the tips of 13 IOL injector models to determine the perimeter, tip angle, and cone angle of each. Injectors were analyzed before and after IOL insertion. Surgery was performed on rabbits with 71 IOL injectors of 13 models, and custom gauges were used to determine the incision size before and after surgery. The injector dimensions varied by model; tip diameter, tip angle, and cone angle ranged from 1.44 to 2.12mm, 29.7 to 66.5 degrees and 0.6 to 10.8 degrees, respectively. The incision size through which surgery was successfully performed also varied by injector model; the initial incision sizes ranged from 2.0 to 2.63mm. For all injectors, there was wound enlargement after IOL insertion that ranged from a 0.1 to 0.65mm increase in incision length. The dimensions and injection systems varied with each IOL injector. All injectors led to postoperative wound stretch after IOL insertion, with no final incision measuring less than 2.0mm. These findings suggest that the clear cornea incision should have a width corresponding to the injector diameter.

Corneal incision architecture after IOL implantation with three different injectors: an environmental scanning electron microscopy study.

To evaluate by Environmental Scanning Electron Microscopy (ESEM) the corneal incision architecture after intraocular lens (IOL) implantation in pig eyes, using manual, automated injectors or preloaded delivery systems. Twenty-four pig eyes underwent IOL implantation in the anterior chamber using three different injectors: manual (Monarch III) (n=8), automated (AutoSert) (n=8), or a preloaded system (UltraSert) (n=8). Acrysof IQ IOLs, 21 Dioptres (D) (n=12) and 27D (n=12), were implanted through 2.2mm clear corneal incisions. Incision width was measured using corneal calipers. The endothelial side of the incision was analyzed with ESEM. In each group, the final size of the corneal wound after IOL implantation, measured by calipers, was 2.3-2.4mm. The incision architecture resulted more irregular in the Monarch group compared with the other injectors. In every group the 27D IOL-implanted specimens showed more alterations than in 21D IOL-implanted samples, and this was less evident in the UltraSert group. The Descemet tear length was higher in the Monarch group than AutoSert and UltraSert group. The automated and preloaded delivery systems provided a good corneal incision architecture; after high-power IOL implantation the incisions were more regular and less damaged with the preloaded system than with the other devices.

The Effect of Eye Patching on Clear Corneal Incision Architecture in Phacoemulsification: A Randomized Controlled Trial.

To investigate the effects of postoperative eye patching on clear corneal incision architecture in phacoemulsification. A single-center, randomized controlled trial. A total of 132 patients with uncomplicated phacoemulsification were randomly allocated to the intervention or control group. The intervention group received postoperative eye patching for approximately 18 hours, whereas the control group received eye shield. The clear corneal incision architecture was examined postoperatively at 2 hours, 1 day, and 7 days after surgery using optical coherence tomography. Epithelial gaping was significantly reduced on postoperative day 1 in the intervention group (52.4%) compared with control (74.2%) (P = 0.01). No differences were found for other architectural defects. Descemet membrane detachment was associated with lower intraocular pressure on postoperative day 7 (P = 0.02). Presence of underlying diabetes mellitus did not seem to influence architectural defects. Postoperative eye patching facilitated epithelial healing and reduced the occurrence of epithelial gaping on postoperative day 1. It may play a role in protecting and improving corneal wounds during the critical immediate postoperative period.

Long-term follow-up for bimanual microincision cataract surgery: comparison of results obtained by surgeons in training and experienced surgeons.

PurposeTo determine the efficacy of bimanual microincision cataract surgery (B-MICS) performed by surgeons in training, evaluating clinical results, posterior capsule opacification (PCO) incidence, and clear corneal incision (CCI) architecture in a long-term follow-up and comparing results with those obtained by experienced surgeons.Patients and methodsEighty eyes of 62 patients operated on by three surgeons in training who used B-MICS technique for the first time were included in the study (Group A). Eighty eyes of 59 patients who underwent B-MICS by three experienced surgeons were included as a control group (Group B). Best corrected visual acuity, astigmatism, corneal pachymetry, and endothelial cell count were evaluated before surgery and at 1 month and 18 months after surgery. Anterior segment optical coherence tomography images were obtained to study the morphology of CCIs. PCO incidence was evaluated using EPCO2000 software.ResultsOut of 160 surgeries included in the study, mean best-corrected visual acuity improvement at 18 months was 0.343±0.246 logMAR for Group A, and 0.388±0.175 logMAR for Group B, respectively. We found no statistically significant induced astigmatism nor corneal pachymetry changes in either group, while we noticed a statistically significant endothelial cell loss postoperatively in both groups (P<0.05). In Group A, mean PCO score was 0.163±0.196, while for Group B, it was 0.057±0.132 (P=0.0025). Mean length and inclination of the CCIs for Group A and Group B were, respectively, 1,358±175 µm and 1,437±256 µm and 141.8°±6.4° and 148.7°±5.1°. As regards corneal architecture in the 320 CCIs considered, we found posterior wound retractions and endothelial gaps, respectively, 9.8% and 11.6% for Group A and 7.8% and 10.8% for Group B.ConclusionB-MICS performed by surgeons in training is an effective surgical technique even when assessed after a long-term follow-up. PCO incidence resulted in being higher for less experienced surgeons. Corneal incisions were shorter and less angled in surgeons in training in comparison with results obtained by expert surgeons.

Study of fluid ingress through clear corneal incisions following phacoemulsification with or without the use of a hydrogel ocular bandage: a prospective comparative randomised study.

To assess the use of a hydrogel ocular bandage (HOB) on clear corneal incisions in phacoemulsification cataract surgery and determine whether HOB reduces ocular surface contaminants ingress after routine surgery. In this prospective randomized controlled study, thirty eyes of patients undergoing uneventful phacoemulsification were recruited consecutively and randomly assigned to have a HOB applied to the corneal incision at the end of the surgery or not. At the end of the surgery, trypan blue (TRB) was instilled on the ocular surface, aqueous fluid was aspirated from the anterior chamber (AC) and its optical density was measured using ultraviolet spectrophotometry. The corneal incisions were examined postoperatively using anterior segment optical coherence tomography. Main outcome measures were concentration of TRB in the AC, corneal incision architecture, intraocular pressure (IOP) and Seidel test. All incisions were Seidel negative. The mean IOP in the immediate postoperative period was 18.1 ± 5.48 mmHg for the intervention group and 16.9 ± 5.7 mmHg for the control group (p > 0.05). No architectural differences of the incisions between the two groups were noted. The total mean length of the three-step corneal incisions in the two groups was 2261.2 ± 96.92 μm and 2263 ± 119.75 μm, respectively (p > 0.05). No trace of TRB was detected in any of the samples. Proper surgical wound construction without the use of a HOB is efficient in preventing the ingress of fluid through the main corneal incision postoperatively.

The LENSAR® Laser System–fs 3D for Femtosecond Cataract Surgery

The LENSAR® Laser System’s ergonomic design permits flexible functionality in any operating environment. Its low-pressure liquid interface eliminates corneal compression and facilitates accurate and complete capsulotomy construction. The Augmented Reality™ imaging system utilises a variable super luminescent diode for scanning structured illumination to provide high-contrast, high-definition targets, which guide the laser. Real-time imaging adjustments compensate for minute degrees of tissue displacement, permitting unrivalled precision in corneal incision architecture. Precise laser spot application allows fragmentation of all grades of cataract, without the need for unnecessarily large safety margins. Iris registration compensates for cyclotorsion in the construction of arcuate incisions by aligning preoperative corneal biometry to intraoperative imaging. The ability to define the cataract grade intraoperatively facilitates efficient phacofragmentation by permitting surgeon-specified preset patterns for the full range of nuclear densities. The LENSAR Laser System represents the state of the art in femtosecond cataract surgery.

The LENSAR® Laser System–fs 3D for Femtosecond Cataract Surgery

The LENSAR® Laser System’s ergonomic design permits flexible functionality in any operating environment. Its low-pressure liquid interface eliminates corneal compression and facilitates accurate and complete capsulotomy construction. The Augmented Reality™ imaging system utilizes a variable super luminescent diode for scanning structured illumination to provide high-contrast, high-definition targets, which guide the laser. Real-time imaging adjustments compensate for minute degrees of tissue displacement, permitting unrivalled precision in corneal incision architecture. Precise laser spot application allows fragmentation of all grades of cataract, without the need for unnecessarily large safety margins. Iris registration compensates for cyclotorsion in the construction of arcuate incisions by aligning preoperative corneal biometry to intraoperative imaging. The ability to define the cataract grade intraoperatively facilitates efficient phacofragmentation by permitting surgeon-specified preset patterns for the full range of nuclear densities. The LENSAR Laser System represents the state of the art in femtosecond cataract surgery.

Clear Corneal Incision Architecture Imaging after Torsional Phacoemulsification of Hard Nuclear Cataract through a 2.2 mm and a 3.0 mm Large Tunnel

Purpose: To compare the morphological characteristics and the wound edema degree of clear-cornea microincisions and small-incisions for hard cataract removal.Setting: The Eye Hospital of Wenzhou Medical College.Design: Prospective randomized study. Methods: Fifty eyes from 36 consecutive patients with hard cataract were included. They were randomized to have phacoemulsification through a clear-cornea microincision (2.2 mm, n=25) or small-incision (3.0 mm, n=25). Anterior segment optical coherence tomography evaluation was performed preoperatively and postoperatively, including wound architecture and incisional corneal thickness (ICT).Results: Endothelial gaping was more common in the 2.2 mm group than in the 3.0 mm group at 2 hours (48 vs 12%) and 1 week (28 vs 12%) postoperatively, although the statistical difference was significant only at 2 hours. There was no statistically significant difference between the two groups in the incidence of epithelial gaping, local detachment of Descemet’s membrane, loss of coaptation, and posterior wound retraction. At 2 hours and 1 week after surgery, the mean ICTd was slightly higher in 3.0 mm group (52.1±12.5% and 46.4±12.3%, respectively) than in 2.2 mm group(51.4±11.6% and 40.6±15.1%, respectively), with no statistically significant differences. On the contrary, the ICTd was statistically higher in 3.0 mm group than 2.2 mm group at 1 month (16.8±10.0% vs 10.2±5.8%, P = 0.007) and 3 months (12.1±8.1% vs 6.0±4.5%, P = 0.002).Conclusion: In hard cataract phacoemulsification, microincisions increase the risk of endothelial gaping in the early postoperative period, compared to small incisions. However, they induce a lower amount of corneal edema.

Corneal Wound Architecture and Integrity After Torsional and Mixed Phacoemulsification: Evaluation of Standard and Microincisional Coaxial Techniques

To compare the effects of torsional and mixed ultrasound on clear corneal incision architecture, wound integrity, and apposition using standard (2.75 mm) and microincisional (2.2 mm) coaxial phacoemulsification. Twenty human cadaver eyes (4 groups of 5 eyes) underwent simulated coaxial phacoemulsification for 45 seconds of ultrasound time (group 1 = 2.75 mm, 100% torsional; group 2 = 2.2 mm, 70% torsional; group 3 = 2.2 mm, 100% torsional; group 4 = 2.2 mm, mixed ultrasound). All phacoemulsification settings were kept constant across each group. Following phacoemulsification, intraocular pressure (IOP) was cyclically raised and lowered from 0 to 125 mm Hg. Two eyes from each group had India ink placed over the wound and were observed for leakage and for histopathologic examination. Eyes not exposed to India ink (three eyes of each group) were examined using anterior segment optical coherence tomography (OCT) and scanning electron microscopy (SEM). Wound leakage was evident in one eye from group 1 and no eyes from the other three groups. Histopathologic examination revealed no India ink penetration in any of the eyes studied. Anterior segment OCT showed good wound apposition in each group. SEM demonstrated partially compromised endothelium and Descemet's membrane in all eyes studied from each group. No differences in corneal wound architecture and integrity were observed. Torsional and mixed ultrasound settings do not appear to induce any adverse effects on corneal wound architecture and integrity in standard and microincisional coaxial phacoemulsification techniques.

Optical coherence tomography of the effects of stromal hydration on clear corneal incision architecture

To evaluate the effects of stromal hydration on clear corneal incision (CCI) architecture immediately after surgery using anterior segment optical coherence tomography (AS-OCT). Department of Ophthalmology, Royal Berkshire Hospital, Reading, United Kingdom. Clear corneal incisions in adult eyes were examined using a Visante AS-OCT imaging system within 1 hour of surgery. Half the CCIs had stromal hydration with a balanced salt solution and half did not. Incisions were made with a 2.75 mm steel keratome. Intraocular pressure (IOP) was measured within 90 minutes after surgery. The CCI length and corneal thickness at the CCI site were measured using software built into the AS-OCT system. Thirty CCIs were evaluated. Stromal hydration significantly increased the measured CCI length (P<.05, t test); this was the result of a trend toward increased corneal thickness at the CCI site with hydration (P<.1, t test). The mean CCI length was 1.69 mm +/- 0.27 (SD) (range 1.31 to 2.32 mm) with hydration and 1.51 +/- 0.23 mm (range 1.30 to 1.95 mm) without hydration. The mean IOP was 20.9 +/- 8.18 mm Hg and 15.8 +/- 8.20 mm Hg, respectively. The IOP tended to be higher with hydration (P<.1, t test). Local detachment of Descemet membrane was more likely with stromal hydration (63%) than without (25%). Stromal hydration significantly increased CCI length and tended to leave the eye with a higher early postoperative IOP, showing the importance of taking stromal hydration into account when designing similar OCT studies of CCI architecture.

Clear corneal incision architecture in the immediate postoperative period evaluated using optical coherence tomography

Clear corneal incision architecture in the immediate postoperative period evaluated using optical coherence tomography

Clear corneal incision architecture in the immediate postoperative period evaluated using optical coherence tomography

To investigate clear corneal incision (CCI) architecture in the immediate postoperative period using optical coherence tomography (OCT). Prince Charles Eye Unit, King Edward VII Hospital, Windsor, United Kingdom. Thirty-four CCIs in 34 adult eyes were examined prospectively using the Carl Zeiss Visante anterior segment OCT imaging system within 1 hour of uneventful phacoemulsification cataract surgery. The CCIs were created using 4 widths of stainless steel blades (2.20 mm, 2.50 mm, 2.75 mm, and 3.20 mm). Immediately afterward, a Seidel test, an inverse Seidel test, and intraocular pressure (IOP) measurements were performed independently. The OCT images were randomized and masked before evaluation. Approval was obtained from appropriate research and ethics committees. The mean CCI length was 1.61 mm +/- 0.26 (SD) (range 1.10 to 2.25 mm). The mean incision angle was 40.7 +/- 9.43 degrees (range 24 to 56 degrees). Five CCI architectural features were noted with the following frequencies: epithelial gaping (12%), endothelial gaping (41%), endothelial misalignment (65%), local detachment of Descemet's membrane (62%), and loss of coaptation (9%). A reduction in wound apposition up to 20% was caused by endothelial gaping and up to 25%, by loss of coaptation, in a bidimensional image. The mean postoperative IOP was 16.1 +/- 9.02 mm Hg (range 3 to 46 mm Hg). The IOP was lower with local detachment of Descemet's membrane (P<.1). Other CCI architectural features varied predicatively with IOP, but not with blade width. Optical coherence tomography architectural features of endothelial gaping and loss of coaptation theoretically reduce CCI structural integrity in the immediate postoperative period. These features appeared to be more common at low IOP and could represent significant risk factors for endophthalmitis.

Corneal wound architecture and integrity after phacoemulsification: Evaluation of coaxial, microincision coaxial, and microincision bimanual techniques

To compare the effects of microincision bimanual phacoemulsification, standard coaxial phacoemulsification, and microincision coaxial phacoemulsification on clear corneal incision architecture and wound integrity.Department of Ophthalmology, Duke University, Durham, North Carolina, USA.A prospective study of 15 human cadaver eyes (3 groups of 5 eyes) ranging 1 to 4 days postmortem had simulated phacoemulsification by bimanual phacoemulsification (1.2 mm incision), standard coaxial phacoemulsification (2.75 mm), or microincision coaxial phacoemulsification (2.2 mm). All phacoemulsification settings were kept constant across each group. After phacoemulsification, intraocular pressure (IOP) was cyclically raised and lowered from 0 to 125 mm Hg. Two eyes in each group had India ink placed above the wound, and the IOP was varied as above. Entry of India ink into the wound or aqueous leakage from the wound was recorded. The same 2 corneas in each group were removed for histopathologic review of India ink penetration. Scanning electron microscopy was used to evaluate wound architecture in 1 eye in each group.Spontaneous wound leakage was evident in all 5 eyes having bimanual phacoemulsification, in 1 eye (20%) having standard coaxial phacoemulsification, and no eye having microincision coaxial phacoemulsification. India ink penetration was grossly evident in 2 of 2 eyes having bimanual phacoemulsification, 1 of 2 eyes having standard coaxial phacoemulsification, and neither of the 2 eyes having microincision coaxial phacoemulsification. Scanning electron microscopy showed increased endothelial cell loss and greater compromise to Descemet's membrane with bimanual phacoemulsification than with standard coaxial phacoemulsification or microincision coaxial phacoemulsification.Results in this experimental setting suggest microincision coaxial phacoemulsification and standard coaxial phacoemulsification induce less wound stress and alteration of wound morphology leading to wound leakage than microincision bimanual phacoemulsification.