Pachymetry Changes Research Articles

Comparison of pachymetry values during crosslinking with different riboflavin solutions

Objectives: To compare the effect of two different riboflavin solutions we use in the accelerated crosslinking (CXL) process on the pachymetry value. Materials and Methods: Patients who had accelerated CXL treatment with dextran-free riboflavin solution due to progressive keratoconus were retrospectively screened. Thirty-seven eyes of 27 patients (group 1) treated with Hydroxyl Propyl MethylCellulose (HPMC) and 0.1% riboflavin containing solution and 29 eyes of 23 patients (group 2) treated with D-alpha-tocopheryl polyethylene-glycol 1000 succinate (VE-TPGS) and 0.1% riboflavin containing solution were compared in terms of pachymetry changes during treatment. Results: In groups 1 and 2, the mean age was 23.92 ± 5.66 and 23.30 ± 4.89, respectively. Mean age, gender, initial keratometry values, mean central corneal thickness (CCT) before and after epithelial debridement did not differ significantly between the two groups. The CCT measured after riboflavin instillation was 453.22 ± 37.48 μ in the group 1 and 479.34 ± 38.54 μ in the group 2. After instillation of riboflavin, according to the initial CCT, there was an average thinning of 21.57 ± 16 μ in the group 1 and 18.72 ± 22.13 μ thickening in the group 2. According to the CCT measured after epithelial debridement, a thickening of 20.70 ± 21.77 μ in the group 1 and 62.76 ± 21.65 μ in the group 2 was observed. The rate of change of CCT after riboflavin instillation of significant differences existed between both groups. (p<0.001). Conclusion: VE-TPGS, which is utilized to increase the cornea's permeability to riboflavin tissue during crosslinking treatment, significantly increases the corneal thickness compared to HPMC and provides a safer tissue thickness for ultraviolet A.

Low Dose Atropine in Preventing the Progression of Childhood Myopia: A Randomised Controlled Trial

Purpose To study the efficacy of low dose atropine (0.01%) eye drops in preventing myopia progression in children by comparing the mean change in spherical equivalent (diopter) and axial length (mm) over a period of one year to a control group and study its effect on near vision, pupil size, keratometry and pachymetry. Methods 200 eyes of 100 myopic children were randomized into two groups based on a computer-generated random number table. The treatment group was administered 0.01% atropine eye drop once at bedtime and control group was administered a placebo. The follow up was done 3-monthly for 12 months by assessing the mean change in spherical equivalent and mean change in axial length. Other parameters like near vision, pupil size, keratometry and pachymetry were assessed at each follow up. Result The study was age and sex matched. The mean change in spherical equivalent refraction and axial length was significantly lower in the treatment group (0.31 ± 0.55 D; 0.11 ± 0.22 mm) than the placebo group (0.80 ± 1.65 D; 0.23 ± 0.44 D) (p-value: 0.003). Less steepening of the corneal curvature was observed in the treatment group (0.16 ± 0.28 D vs 0.29 ± 0.3 D; p < 0.001) and the mean change in pachymetry was comparable between the groups (0.00 ± 0.01) (p-value 0.489). No significant change was seen in near vision (96% of the eyes with atropine had no change in near vision; 2% of the eyes had a change of near vision by one line (p-value 0.500); 2% had a change by 3 lines (p-value: 0.07) or pupil size following treatment. Conclusion The use of 0.01% atropine eye drop reduced the progression of myopia over the study period of one year with no significant changes in near vision, pupil size. No patient reported any systemic and local side effects with administration of 0.01% atropine eye drop.

Pachymetric Assessment After EpiSmart® Epithelium-on Cross-Linking for Keratoconus and Post-Surgical Ectasia

PurposeTo assess the change in corneal pachymetry after a novel epithelium-on (EpiSmart®) corneal crosslinking procedure (CXL).MethodsEyes treated as part of the open-label, non-controlled arm of the study “Collagen Crosslinking with Ultraviolet-A in Asymmetric Corneas” (NCT01097447) were examined at baseline, 3-, 6- and 12-months post-CXL. Thinnest pachymetry readings based on Pentacam (OCULUS GmbH, Wetzlar, Germany) were recorded.ResultsA total of 101 eyes met the study inclusion criteria. Thinnest pachymetric readings at baseline averaged 451 ± 50 microns. The mean (± SD) minimum thickness was 450 ± 46 microns at 3 months, 452 ± 47 microns at 6 months, and 451 ± 48 microns at 12 months post-CXL. The changes from baseline (mean ± SE) at 3, 6, and 12 months post-CXL were −1.2 ± 1.5 microns, 0.5 ± 1.6 microns, and 0.4 ± 1.6 microns, respectively. Student’s t-tests showed no statistically significant change in pachymetry from baseline for any exam period.ConclusionThis study demonstrated that, after EpiSmart® epithelium-on CXL, there was no substantial corneal thinning observable on Scheimpflug tomography out to 12 months.

Long-Term Outcomes of Big Bubble Deep Anterior Lamellar Keratoplasty in Mucopolysaccharidoses: A Retrospective Case Series and Review of the Literature.

The purpose of this study was to report the long-term surgical and visual outcomes of patients with mucopolysaccharidoses (MPS) after big bubble deep anterior lamellar keratoplasty (BB-DALK). This was a retrospective case series of patients with MPS who underwent BB-DALK at a single academic institution. All patients had corneal clouding secondary to MPS limiting visual acuity for which keratoplasty was indicated. Each patient was evaluated and underwent surgery by a single surgeon. Reported data included age at keratoplasty, sex, MPS type, best spectacle-corrected visual acuity, change in pachymetry, ocular comorbidities, surgical complications, and MPS-related medication use. Outcomes of 12 eyes from 7 patients with MPS type I (Hurler, Scheie, and Hurler-Scheie) are reported using the newest nomenclature. The mean follow-up was 5.58 years (range: 1-10 years). All cases underwent BB-DALK with a type 1 big bubble during the surgery. Two cases (16.6%) required rebubbling because of partial Descemet membrane detachment. One case was complicated by a suture abscess and required a penetrating keratoplasty. No episodes of rejection occurred. Statistically significant improvement in the best spectacle-corrected visual acuity (from a mean 0.85-0.33 logarithm of the minimum angle of resolution, P = logarithm of the minimum angle of resolution 0.0054) and pachymetry (mean reduction of -145.4 μm, P = 0.0018) was observed. BB-DALK seems to be an acceptable long-term surgical option in patients with MPS. Our findings suggest that this technique is reproducible and can achieve clear corneal grafts with good visual results on a long-term follow-up.

Early corneal pachymetry maps after cataract surgery and influence of 3D digital visualization system in minimizing corneal oedema.

To describe the early topography of corneal swelling occurring after cataract surgery and to evaluate the impact of the three-dimensional (3D) digital visualization system in minimizing corneal oedema. Prospective observational, single-centre, consecutive case series of 134 patients undergoing cataract surgery performed by the same surgeon, with either 3D or conventional visualization systems. Eyes were assigned to two groups based on their anterior chamber depth (group ACD ≤3 mm and group ACD >3 mm). Optical coherence tomography was performed to evaluate postoperative corneal swelling. Three corneal swelling profiles were identified on the first postoperative day type 1, limited corneal oedema near peripheral corneal incisions; type 2, dome-shaped corneal swelling spreading from the principal corneal incision and reaching the paracentral cornea; type 3, continuous oedema spreading from the principal incision to central cornea, with a generalized oedema predominating in the upper part of the cornea. On the first day after surgery, in group ACD ≤3 mm, visual acuity was significantly better in patients undergoing surgery with 3D visualization (0.023 vs 0.072 logMar, p = 0.014) with reduced central corneal thickening 17.3 µm (±3.2) in comparison with conventional visualization 44.0 µm (±9.3) (p = 0.0082). In group ACD >3 mm, no significant association was found between the use of the 3D system and pachymetry changes and early visual rehabilitation. On day 21 after surgery, no significant differences in corneal pachymetry values were observed between the two surgical approaches in both groups. We describe early postoperative corneal map profiles providing insight into the pathogenesis of postoperative corneal swelling and possible prevention strategies. By improving visualization of the narrow surgical space in patients with shallow anterior chambers, the 3D system could help to minimize postoperative corneal oedema.

The Intraoperative Corneal Pachymetry Changes during Accelerated Corneal Cross-linking in Progressive Keratoconus Patients with Thin Corneas.

PurposeTo report the intraoperative corneal pachymetry changes during accelerated corneal cross-linking (A-CXL) in progressive keratoconus patients with thin corneas.MethodsThirty-six eyes (mean age, 22.26 ± 4.02 years) with progressive keratoconic thin corneas (<400 μm without epithelium) who underwent A-CXL with ultraviolet (UV)-A (UVA) (9 mW/cm2) using isotonic riboflavin5-phosphate 0.1% with 1.1% hydroxypropyl methycellulose (RF-HPMC, MedioCROSS M) were included in this retrospective study. Intraoperative corneal pachymetric changes were noted before the procedure, after removal of epithelium, after RF-HPMC instillation, before and after UV irradiation. The mean of corneal pachymetric values were compared statistically.ResultsThe mean corneal pachymetry reduced from 415.72 ± 29.66 to 369.50 ± 23.45 μm after removal of the epithelium (p < 0.05). After the application of RF-HPMC solution the mean thinnest corneal pachymetry (TCP) increased to 412.89 ± 26.94 μm. Statistically significant increase was observed in TCP after saturation with RF-HPMC (p = 0.001). The mean corneal pachymetry before and after UVA irradiation was 419.86 ± 10.41 and 417.47 ± 8.25 μm, respectively (p > 0.05).ConclusionsIsotonic RF-HPMC lead to a significant increase in intraoperative mean TCP. RF-HPMC seems to be a favorable riboflavin option in keratoconus patients with thin corneas.

Compaction of very thin corneas from ultraviolet A riboflavin-vitamin E transepithelial cross-linking

The purpose of the study was to determine the decrease in pachymetry of very thin corneas with advanced keratoconus due to corneal compaction from the ultraviolet-A (UV-A) irradiation phase of transepithelial (epi-on) cross-linking.Twenty removed corneal buttons were obtained from patients who underwent penetrating keratoplasty for advanced keratoconus. Removed corneal buttons selected from among the post-surgical specimens for this study had intact epithelium, no scarring or surgical cautery, endothelial cell density >2500 cells/mm2, and average pachymetry over the measured points of below 400 μm. Corneas were mounted in a Franz chamber. Each epithelial surface was soaked in isotonic riboflavin and D-alpha-tocopheryl polyethylene glycol 1000 succinate (Ribocross® IROMED Group, Italy) for 15 min. Pachymetry was measured at three points over both the shielded and unshielded corneal halves for each corneal button. Surfaces were then washed in saline to remove the Ribocross®. Shields from UV-A irradiation over half of each cornea were then fixed to stand 5 mm above the test corneas. UV-A irradiation using the custom fast cross-linking (CF-CXL) protocol was then performed for the typical 10 ± 1.5 min, for a total energy of 1.08 ± 0.6 J/cm2 after which pachymetry was re-measured.The average percent change in pachymetry was −0.43% ± 0.38% (maximum −1.06%) in the shielded half. Pachymetry change was −6.2% ± 2.2% (maximum 12%) in the cross-linked halves.In conclusion, we estimate that the change in corneal thickness from corneal compaction due to the cross-linking reaction itself was −5.8% ± 2.2%. Scanning electron microscopy of cross-linked corneal segments showed stromal fiber contraction.

Transepithelial Corneal Cross-linking With Supplemental Oxygen in Keratoconus: 1-Year Clinical Results

To evaluate the efficacy and safety of transepithelial corneal cross-linking (CXL) with supplemental oxygen. This was a prospective, non-comparative, pilot cohort study conducted at the National Reference Center for Keratoconus (Toulouse, France) on patients with progressive keratoconus. Transepithelial, pulsed, accelerated CXL was performed in an oxygen-rich atmosphere. Oxygen goggles were applied to the eyes to maintain a high level of oxygen during treatment. The main efficacy outcome was the mean change from baseline in maximum keratometry (Kmax) and the secondary outcomes were the mean changes in flat keratometry (K1), steep keratometry (K2), mean keratometry (Km), corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), and demarcation line depth. The safety outcomes were the incidence of adverse events, the mean change in pachymetry, and endothelial cell count. Thirty-four eyes of 34 patients were included. At 12 months postoperatively, the Kmax decreased by 1.56 ± 1.71 diopters (D) (P < .0001) and CDVA improved by 0.093 ± 0.193 logMAR (P < .02). The K2 and Km decreased by 0.51 ± 1.03 D (P < .02) and 0.40 ± 0.78 D (P < .01), respectively. There was no change in K1 and UDVA. The most frequent adverse event was corneal haze (64.78%). There were neither cases of infectious keratitis or loss of more than two lines in CDVA nor changes in pachymetry or endothelial cell count. Transepithelial CXL performed in an oxygen-rich atmosphere results in improved Kmax and CDVA with good safety. These promising findings suggest that this procedure could be safe and capable of halting the progression of keratoconus. [J Refract Surg. 2021;37(1):42-48.].

Comparison of endothelial cell changes by specular microscopy between Ringer’s and Ringer’s lactate during phacoemulsification

AIM: To compare the difference between using Ringer’s and Ringer’s lactate (RL) solutions as irrigating solutions during phacoemulsification and investigate their effect on corneal endothelium. METHODS: This was a prospective interventional double blinded clinical study that included 100 eyes of 100 patients aged between 50 to 65y suffering from a visually significant age-related cataract and scheduled for routine uncomplicated phacoemulsification. The included eyes were randomly divided into two equal groups (each group included 50 eyes). Group 1 received Ringer’s solution and group 2 received Ringer’s lactate as an irrigating solution. RESULTS: The first group with Ringer’s solution had a mean age of 57.5±8y and the second group with RL solution had a mean age of 58.6±9y. After 3mo, endothelial cell density decreased in group 1 by a mean of 8.5%, and in group 2 by a mean of 3.6% (P=0.013). Additionally, central corneal thickness increased in group 1 by a mean of 6.9% and in group 2 by a mean of 1.5% (P=0.006). By correlating the percentage of change in pachymetry and specular microscopic parameters with volume of irrigation solution used, there was no significant correlation. CONCLUSION: The use of Ringer’s lactate as an irrigating solution is associated with less endothelial cell loss postoperatively in comparison to Ringer’s solution and associated with decreased postoperative edema.

Remodeling of Cornea With Isotretinoin Treatment.

To evaluate the change of corneal epithelial thickness (ET) in subjects using isotretinoin with spectral-domain optical coherence tomography and further to explore reflection of changes on corneal topography. Forty eyes of 40 subjects with acne vulgaris scheduled for oral isotretinoin were included in this prospective study. Subjects were examined with RTVue-XR and Pentacam at baseline, 1th, 3rd, and 6th months of treatment, and 3rd month of isotretinoin cessation. A statistically significant increase was detected in each sector of ET map except inferonasal 7 to 9 mm between baseline and following visits (P<0.05, for all visits). The increase in superior (2-7 mm), inferior (2-7 mm), and maximum values in epithelium statistics and the decrease in superior (2-7 mm), inferior (2-7 mm), minimum, and maximum values in stroma statistics at follow-up visits were significant (P<0.05, for all visits). Central corneal thickness, maximum Ambrosio-relational thickness, average pachymetric-progression index at 1th, 3rd, and 6th months, and thinnest pachymetry, index of surface variance (ISV) at 3rd, and 6th months differed significantly (P<0.05, for specified visits). The regression in parameters was observed at 3rd month of isotretinoin cessation. Isotretinoin treatment induces epithelial thickening and stromal thinning. Remodeling of corneal layers causes statistical differences in ISV and pachymetry-related parameters of Pentacam. The pachymetry changes in cornea return to baseline at the 3rd month of discontinuation of treatment.

Fourier Analysis of Keratometric Data in Epithelium Removal versus Epithelial Disruption Corneal Cross-linking.

Purpose To compare epithelium-removal and epithelium-disruption corneal crosslinking (CXL) methods in Fourier analysis of keratometric data and clinical outcomes.MethodsIn this double masked randomized clinical trial, each eye of 34 patients with bilateral keratoconus was randomly allocated to either the epithelium-removal or epithelium-disruption CXL treatment groups. Ocular examination, refraction, uncorrected and best spectacle-corrected visual acuity (UCVA and BSCVA, respectively) measurements, and Pentacam imaging (keratometry, pachymetry, and Fourier analysis) were performed at baseline and at six-month follow-up period.Results Patients' mean age was 23.3 3.6 years. The preoperative thickness of the thinnest point was 459.20 37.40 µm and 455.80 32.70 µm in the epithelium-removal and epithelial-disruption CXL groups, respectively (P > 0.05). The corresponding figures were 433.50 33.50 µm and 451.90 39.70 µm, respectively, six months after the treatment (P = 0.0001). Irregularity component of the fourier analysis was 0.030 0.016 µm in the epithelium-removal group and 0.028 0.011 µm in the epithelium-disruption group preoperatively (P > 0.05). This measurement was 0.031 0.016 µm and 0.024 0.009 µm, respectively at month 6 (P = 0.04). The epithelium-disruption CXL group had better results in terms of the thickness of the thinnest point and the irregularity component as compared to the epithelium-removal group. The two study groups were comparable in spherical equivalent, mean keratometry, UCVA, BSCVA, or other Fourier analysis components (spherical R min, spherical eccentricity, central, peripheral regular astigmatism, and maximum decentration) (P 0.05).ConclusionThis study shows that epithelium-disruption CXL is superior to epithelium-removal CXL regarding the short-term changes in pachymetry and corneal irregularity. Other evaluated parameters were comparable between the two techniques.

Effect of Riboflavin Solution With Hydroxypropyl Methylcellulose and Eyelid Speculum on Pachymetry Changes During Accelerated Collagen Crosslinking.

To assess corneal thickness changes with isotonic riboflavin (RF) solution with hydroxylpropyl methylcellulose in patients undergoing accelerated corneal collagen crosslinking (CXL) with and without an eyelid speculum. Fifty-two eyes of 48 patients with progressive keratoconus were enrolled in this study. The patients in this study were divided into 2 groups: in group 1 an eyelid speculum was removed during 20-minute RF (0.1%) + hydroxylpropyl methylcellulose (Mediocross M; Avedro Inc, Waltham, MA) instillation, and in group 2 the eyelid speculum was retained in place during the entire CXL procedure. All patients underwent accelerated CXL using continuous ultraviolet-A (UVA) light exposure at 9 mW/cm for 10 minutes; total energy dose was 5.4 J/cm. Intraoperative ultrasound pachymetry measurements were obtained before and after epithelial removal, after RF loading, and after UVA light exposure at 5 and 10 minutes. The preoperative pachymetric measurements decreased in both groups after the removal of epithelium [group 1 (n = 26): -25 μm, group 2 (n = 26): -31 μm, P = 0.234]. Although the thinnest pachymetry significantly increased after soaking in both group 1 (52.26 μm) and group 2 (27.88 μm, P < 0.001), closure of the eyelids during RF instillation further increased the pachymetry readings (P < 0.0001). The corneal thickness remained stable in both groups during UVA irradiation at 5 and 10 minutes (P > 0.05). Closure of the eyelids further induces corneal swelling that may offer an advantage to improve safety of the procedure particularly in thin corneas.

Biomechanical changes in the cornea following cataract surgery: A prospective assessment with the Corneal Visualisation Scheimpflug Technology.

Intraocular pressure (IOP) is often reduced following cataract surgery. Postoperative changes in corneal stiffness are likely to be at least partly responsible for any reduction in IOP measured with applanation tonometry. To determine the effect of cataract surgery and corneal incision size on corneal biomechanics. Prospective randomized trial. One hundred prospectively enrolled patients qualifying for cataract surgery. Participants were randomized to clear corneal incisions with a 2.20 or 2.85 mm keratome. Corneal Visualisation Scheimpflug Technology (Corvis-ST) tonometry and dynamic corneal response measurements were obtained preoperatively, and 3 mo postoperatively. Multiple regression analysis was completed using R software. Corvis-ST biomechanical parameters. Ninety-three eyes of 93 patients were included in the final analysis. Mean Corvis-ST biomechanically corrected IOP decreased by 3.63 mmHg postoperatively (95% confidence interval = 2.97-4.35, P ≤ 0.01), and central pachymetry increased by 6.96 μm (4.33-9.59, P ≤ 0.01). Independent of IOP and pachymetry changes, mean (±SE) corneal first applanation stiffness parameter reduced by 9.761 ± 3.729 (P = 0.01) postoperatively. First applanation velocity increased by 0.007 ± 0.002 ms, second applanation velocity increased by 0.012 ± 0.004 ms (P ≤ 0.01), the first applanation deformation amplitude increased by 0.008 ± 0.002 mm (P ≤ 0.01) and the deflection amplitude at highest concavity increased by 0.030 ± 0.069 (P ≤ 0.01). There were no significant differences between different incision size groups. Corneal stiffness is reduced 3 mo following cataract surgery and is associated with falsely low IOP measurements. This finding may be important for glaucoma patients and in particular when assessing the effectivity of minimally invasive glaucoma surgery devices.

Descemet Endothelial Thickness Comparison Trial: A Randomized Trial Comparing Ultrathin Descemet Stripping Automated Endothelial Keratoplasty with Descemet Membrane Endothelial Keratoplasty

To compare clinical outcomes of ultrathin Descemet stripping automated endothelial keratoplasty (UT-DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) in the treatment of corneal endothelial dysfunction. Patient and outcome-masked, randomized controlled clinical trial. Patients with damaged or diseased endothelium from Fuchs endothelial dystrophy or pseudophakic bullous keratopathy who were considered good candidates for DMEK or UT-DSAEK. Study eyes were randomized by the eye bank to UT-DSAEK or DMEK 1 to 2 days before surgery. The primary outcome of the trial was best spectacle-corrected visual acuity (BSCVA) at 6 months. Secondary outcomes included 3- and 12-month BSCVA; 3-, 6-, and 12-month endothelial cell counts; intraoperative and postoperative complications; and change in pachymetry. A total of 216 patients with endothelial dysfunction were screened, and 50 eyes of 38 patients were enrolled by 2 surgeons at Casey Eye Institute at Oregon Health & Science University in Portland, Oregon, and at Byers Eye Institute at Stanford University in Palo Alto, California. Overall, we found DMEK to have better visual acuity outcomes compared with UT-DSAEK after correcting for baseline visual acuity: compared with UT-DSAEK, those randomized to DMEK had 1.5 lines better BSCVA at 3 months (95% confidence interval [CI], 2.5-0.6 lines better; P= 0.002), 1.8 lines better BSCVA at 6 months (95% CI, 2.8-1.0 lines better; P < 0.001), and 1.4 lines better BSCVA at 12 months (95% CI, 2.2-0.7 lines better; P < 0.001). Average endothelial cell counts were 1963 cells/mm2 in DMEK and 2113 cells/mm2 in UT-DSAEK at 6 months (P= 0.17) and 1855 cells/mm2 in DMEK and 2070 cells/mm2 in UT-DSAEK at 12 months (P= 0.051). Intraoperative and postoperative complication rates were similar between groups. Descemet membrane endothelial keratoplasty had superior visual acuity results compared with UT-DSAEK at 3, 6, and 12 months in patients with isolated endothelial dysfunction with similar complication rates.

Biomechanical assessment of healthy and keratoconic corneas (with/without crosslinking) using dynamic ultrahigh-speed Scheimpflug technology and the relevance of the parameter (A1L-A2L).

To examine corneal biomechanics in healthy and keratoconic eyes, with or without crosslinking obtained by ultrahigh-speed Scheimpflug measurements (Corvis ST). One hundred and seventeeneyes were studied in three groups: group 1 (n=39) contained keratoconic eyes without crosslinking. Group 2 (CXL; n=28) comprised keratoconic eyes after crosslinking. These were compared with a control group (n=50 matched healthy eyes). In addition, 10 keratoconus patients, before and after CXL treatment, respectively, were examined. The novel parameter A1L-A2L demonstrated highly significant differences between crosslinked corneas and untreated keratoconic or healthy corneas. Velocity during second applanation (A2V) and deformation amplitude (DA) were significantly increased in crosslinked keratoconic eyes both compared with untreated keratoconic eyes and with healthy controls. Radius at highest curvaturealso was significant among all groups. Inward applanation length (A1L) was significantly increased in controls, whereas outward applanation length (A2L) was significantly reduced in crosslinked keratoconic eyes compared with both other groups. The follow-up analysis revealed statistically significant changes in pachymetry and intraocular pressure and showed tendencies towards significance in applanation times 1 and 2 and in DA. Both A2V and A2L are viable parameters to discriminate healthy from keratoconic but also crosslinked from non-crosslinked keratoconic corneas. The difference of A1L-A2L could reliably discriminate crosslinked from non-crosslinked and healthy corneas. Follow-up examination in a small cohort allows distinction between crosslinked and untreated keratoconus in follow-up examinations. The difference of A1L-A2L could reliably discriminate crosslinked from non-crosslinked and healthy corneas. Measurements of corneal deformation using dynamic ultrahigh-speed Scheimpflug technology are reproducible and provide useful information about keratoconus assessment and biomechanics. Therefore, the Corvis ST seems to provide useful technology to monitor therapeutic success of crosslinking treatment.

Comparison of corneal pachymetry changes and surgically induced astigmatism of microcoaxial phacoemulsification surgery and coaxial phacoemulsification surgery

DOI : 10.26650/IUITFD.396179 Amac: 2,2 mm’lik kesi ile yapilan mikrokoaksiyal fakoemulsifikasyon cerrahisini, 2,75 ve 3,2 mm’lik kesi ile yapilan standart koaksiyal fakoemulsifikasyon cerrahisi ile cerrahiye bagli astigmatizma (CBA) ve pakimetrik degisimler acisindan karsilastirmak. Gerec ve Yontem: Katarakt operasyonu yapilan 39 olgunun kayitlari retrospektif olarak incelendi. Olgularin hangi buyuklukte kesi ile opere edilecekleri rastgele belirlendi. Mikrokoaksiyal grupta 15 goz, standart koaksiyal grupta ise 24 goz bulunmaktaydi, Olgulara preoperatif ve postoperatif 1. ayda Pentacam Scheimpflug kamera (OCULUS Inc., Almanya) ile kornea topografisi analizi yapildi. Pentacam’in iki topografi arasindaki degisikligi hesaplayan fark haritasindaki astigmatizma ve pakimetri degerleri karsilastirildi. Vektoryel analiz programi kullanarak cerrahiye bagli astigmatizma degerleri hesaplandi. Bulgular: Postoperatif 1. aydaki vektoryel analiz programi ile hesaplanan CBA degerleri mikrokoaksiyal cerrahi grubunda 0,55±0,37 D, koaksiyal cerrahi grubundaki 0,53±0,24 D olarak olculdu ve aralarinda anlamli bir fark yoktu (p=0,743). Pentacam fark haritasinda olcumlerde mikrokoaksiyal cerrrahi grubunda astigmatizma degisimi 0,41±0,62 D saptanirken koaksiyal cerrahi grubunda 0,44 ± 0,40 D saptandi. Gruplar arasinda anlamli farklilik yoktu (p=0,578 ). Postoperatif 1. haftadaki gorme keskinligi anlamli bir sekilde mikrokoaksiyal grupta daha yuksek duzeydeydi. (p=0,004).Mikrokoaksial kesi ile opere edilen grupta kornea kalinliginda postoperatif 1. ayda ortalama 6,47 ± 21,16 mikron azalma saptanirken diger grupta ortalama 12,62 ±30,01 mikron artis saptandi. Aralarindaki fark anlamli bulundu (p=0,004). Sonuc: Postoperatif 1. aydaki CBA degerleri, literaturdeki CBA degerleri ile benzer sonuclar vermis ancak iki grup arasinda anlamli bir farklilik saptanmamistir. Mikrokoaksiyal cerrahi grubunda postoperatif gorsel rehabilitasyon daha erken saglanmaktadir.

Intraoperative optical coherence tomography to evaluate the effect of the eyelid speculum on corneal pachymetry during accelerated corneal cross-linking (9 mW/cm2).

PurposeTo investigate intraoperative anterior segment optical coherence tomography (AS-OCT) to compare pachymetry changes between two methods (group 1: speculum-on, group 2: speculum-off during riboflavin instillation stage) during corneal cross-linking /CXL) (9 mW/cm2 for 10 min) in keratoconic patients.MethodsIn this interventional case series, 11 eyes (11 patients) in group 1 and 14 eyes (14 patients) in group 2 were enrolled. Pachymetry measurements by spectral domain OCT was performed at baseline, after epithelial removal, after 30 min of imbibition with riboflavin, and after UV irradiation. Repeated measures analysis of variance was used to compare the trend of changes in different stages of the procedure within and between two groups.ResultsThe corneal thinnest pachymerty (CTP) at baseline, after epithelial removal, 30 min of riboflavin instillation, and irradiation was 469.8±26.5, 438.0±27.1, 354.3±28.4, 367.1±31.8 microns in group 1 and 463.2±25.1, 438.0±27.1, 421.6±54.0, 386.9±34.0 microns in group 2, respectively. Group 1 showed a significantly greater decrease in the corneal pachymetry (P<0.001) during riboflavin instillation, while in group 2 a greater decrease in CTP was observed during the UV irradiation phase (P=0.002).ConclusionsUsing the intraoperative OCT, the speculum-off group had a more stable corneal pachymetry during riboflavin instillation time. Despite this, the effect was not lasting throughout the procedure; significant changes were noted in the corneal pachymetry at the end of operation in both groups; further highlighting the limitations imposed by corneal stromal shrinkage using isotonic dextran containing riboflavin solution for CXL.

Assessment of the Effects of Intense Pulsed Light Procedure in Porcine Eyes with Different Treatment Strategies

1.1.Introduction: The use of intense pulsed light (IPL) increased in recent years. This study aimed to identify the types and degrees of eye injury caused by IPL in ‘’ex vivo’’ porcine eye, correlating the distance from the shooting location of the ocular region, power and pulse duration used. 1.2.Methods: Experimental study. Intense pulsed light (IPL) was applied in five different treatment strategies (7J/5ms, 9 J/12ms, 10J/18 ms, 11J/26ms and 12J/34 ms) with corneal thickness evaluation pre and post procedure and classification of degree of eye injury observed in biomicroscopy slit lamp in the phase after the procedure. 1.3.Results: There was no change in pachymetry in the group of lower power and frequency - Group 1 (7J/5 ms), but from 9J/12 ms (groups 2, 3, 4 and 5) all groups presented reduction of corneal thickness. The biomicroscopy analysis in slit lamp showed that inferior keratitis was observed a greater number of eyes subjected to intense pulsed light procedure with minor powers (7 and 9J) and iris lesion were observed a greater number of eyes subjected to light procedure intense pulsed with greater powers (12J). 1.4.Conclusion: Ocular adverse effects were observed in all strategies of the intense light pulse procedure in porcine eye. The intraocular effects such as iris lesions were more evident in treatments with higher powers. Change of corneal thickness was observed with intense pulsed light from 9J and 12 ms. Because of the lesions observed in the evaluation after the procedure we corroborate the recommendation of using scleral lenses, possibly made of stainless steel, to dissipate the energy of the IPL when ophthalmic procedures or esthetic procedure near the eyeball margin.

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.

Isotonic riboflavin and HPMC with accelerated cross-linking protocol.

The aim of this study was to monitor corneal pachymetry changes during accelerated collagen cross-linking (CXL) for keratoconus while using isotonic riboflavin with HPMC. All consecutive patients who underwent CXL for progressive keratoconus, using accelerated protocol and isotonic riboflavin with HPMC, from December 2012 to September 2013 were included in the study. The corneal pachymetry measurements were obtained at different time points: after epithelial removal, after riboflavin application for 20 minutes, and after ultraviolet A irradiation for 10 minutes at 9 mW/cm. A total of 14 eyes of 14 consecutive patients were included in this study. The mean age of the patients was 19 ± 8 years. There were 8 left eyes and 6 right eyes. After epithelial debridement, the thinnest pachymetric readings were between 324 and 452 μm (average, 401.4 ± 40.7 μm). No significant difference (P = 0.80) was found between the deepithelialized corneal thickness and after 20 minutes of isotonic riboflavin with HPMC (pachymetric average, 405.3 ± 37.5 μm). Pachymetric average after ultraviolet A irradiation was 419.29 ± 20.60 μm. There was no statistical significant change in the corneal thickness after the irradiation (P = 0.24). During corneal CXL using isotonic riboflavin and HPMC with accelerated cross-linking protocol, no significant decline in the corneal thickness was demonstrated.