Changes In Corneal Thickness Research Articles

Efficacy of Topical Timolol Eye Drops in Treatment of Myopic Regression After Small Incision Lenticule Extraction: A Case Report

Purpose: To describe a patient with high myopia who experienced slight myopic regression twice during follow-up after small incision lenticule extraction (SMILE), which can be eased by topical treatment of timolol. Methods: Case report. Results: Six months after a SMILE procedure for high myopia in both eyes, the patient's uncorrected distance visual acuity (UDVA) was 0.8 and both eyes lost one line compared to preoperative corrected distance visual acuity (CDVA) by myopic shift, which was accompanied by central corneal epithelial thickening. After 2 months of treatment with topical timolol eye drops, the UDVA improved two more lines with flattened corneal curvature and thinned epithelial thickness. After 5 months without timolol treatment, he lost two lines of UDVA again with thicker epithelial thickness. After another 2 months of treatment with timolol, the epithelial thickness could be seen to have thinned month by month, and the UDVA improved two or more lines. There was no notable myopic shift in both eyes for the next 3 months with medication withdrawal. During the whole follow-up period, the change in corneal and epithelial thickness remarkably fluctuated with the timolol treatment, but the posterior corneal curvature was stable. Conclusions: This case report describes refractive regression that can repeatedly occur in the middle and long term after a SMILE procedure for high myopia, which could be correlated with the thickening of the central corneal epithelium. Treatment with timolol eye drops can help to improve visual acuity by thinning the compensated epithelial thickness to flatten corneal curvature. [ Journal of Refractive Surgery Case Reports. 2023;3(4):e47–e52.]

A comparative study of corneal topographical and central corneal thickness changes in diabetics and non-diabetics before and after phacoemulsification: A study protocol

Diabetes is a chronic metabolic disorder and it has its effects in the eye causing various ocular complications. It is also found that diabetes causes changes in the corneal morphology. Corneal components such as epithelium, endothelium, nerves, and immune cells are affected by hyperglycemia. These changes cause a significant effect on vision in individuals with diabetes. Assessment of corneal parameters like central corneal thickness and corneal topography changes related to diabetes are essential in patients undergoing modern-day cataract surgery like phacoemulsification. Systemic condition like diabetes along with cataract surgery like phacoemulsification can influence corneal healing and fluid balance leading to changes in corneal thickness. Postoperative changes in the cornea are also important to assess the corneal health after the surgery. Comparison of preoperative and postoperative corneal measurements help in assessing the effect of phacoemulsification and health status of the cornea. Study of these changes help in preventing complications and effect on visual outcome and specialised management for individuals with diabetes undergoing cataract surgery. In diabetic patients the risk of intraoperative and postoperative complications in cataract surgery increases compared to non diabetic patients. The aim of the study is to compare corneal curvature and astigmatism by corneal topography and central corneal thickness in diabetic patients and controls before and after phacoemulsification. CTRI registration number: REF/2023/08/071341

Development and validation of a reliable rabbit model of limbal stem cell deficiency by mechanical debridement using an ophthalmic burr

A simple and reproducible method is necessary to generate reliable animal models of limbal stem cell deficiency (LSCD) for assessing the safety and efficacy of new therapeutic modalities. This study aimed to develop and validate a rabbit model of LSCD through mechanical injury. The corneal and limbal epithelium of New Zealand White rabbits (n = 18) were mechanically debrided using an ophthalmic burr (Algerbrush II) with a 1.0-mm rotating head after 360° conjunctival peritomy. The debrided eyes were serially evaluated for changes in corneal opacity, neo-vascularization, epithelial defect and corneal thickness using clinical photography, slit lamp imaging, fluorescein staining, and anterior segment optical coherence tomography scanning (AS-OCT). Following this, an assessment of histopathology and phenotypic marker expression of the excised corneas was conducted. The experimental eyes were grouped as mild (n = 4), moderate (n = 10), and severe (n = 4) based on the grade of LSCD. The moderate group exhibited abnormal epithelium, cellular infiltration in the stroma, and vascularization in the central, peripheral, and limbal regions of the cornea. The severe group demonstrated central epithelial edema, peripheral epithelial thinning with sparse goblet cell population, extensive cellular infiltration in the stroma, and dense vascularization in the limbal region of the cornea. A significant decrease in the expression of K12 and p63 (p < 0.0001) was observed, indicating the loss of corneal epithelium and limbal epithelial stem cells in the LSCD cornea. This study demonstrates that the Alger brush-induced mechanical debridement model provides a reliable model of LSCD with comprehensive clinic-pathological features and that is well suited for evaluating novel therapeutic and regenerative approaches.

Evaluation of the corneal thickness and endothelial changes following uncomplicated phacoemulsification in diabetic and non-diabetic patients with pseudo-exfoliation syndrome by specular microscopy.

To evaluate corneal endothelial cell changes following uncomplicated phacoemulsification in diabetic patients with PEX, compared with diabetic patients and non-diabetic patients with PEX. This prospective, comparative, non-randomized cohort study included 61 eyes of 61 patients who were diagnosed as having senile cataract. Patients were divided into three groups: Group (1) included 19 eyes of patients with DM and PEX, group (2) included 22 eyes of diabetic patients, and group (3) included 20 eyes of patients with PEX. All included patients had uncomplicated phacoemulsification with IOL implantation. Patients were examined by non-contact specular microscopy (NIDEK, CEM-530, Japan), preoperatively and postoperatively at regular follow-up periods (one, three, and six months postoperatively) with analysis of the endothelial cell density, percentage of hexagonal cells, CV, and CCT. By the end of follow-up period, there was a statistically significant reduction in ECD and HEX with a significant increase in CV and CCT in group one (DM-PEX). In group two (DM), a statistically significant decrease in ECD and HEX with a significant increase in CCT was reported, while in group three (PEX), the only significant difference was found in the form of ECD reduction. Patients with DM and PEX had significant changes regarding ECD, CV, HEX, and CCT which were more pronounced than in patients with DM only or PEX only. More attention should be paid while operating on diabetic patients with PEX to save corneal endothelium and decrease postoperative complications. The study was retrospectively registered (16 July 2021) on ClinicalTrials.gov (NCT04965168).

Changes in Corneal Epithelial Thickness in Relation to Vision, Contrast Sensitivity and Ocular Aberrations After Lasik

Purpose: The assessment of changes in corneal epithelial thickness at the center of the cornea (ET center) and at the apex of the cornea (ET peak) in relation to vision, corneal aberrations (LOAs and HOAs) and contrast sensitivity (C.S) after LASIK. Material and Methods: Twenty-seven patients (27 eyes) with a mean age of 32 years (range 22-50), 9 males and 18 females were included in the study and underwent LASIK. Mean follow up was 12.18 +/- 1.48 (range from 9 to 18 months). Results: A statistically significant difference was found between preoperative and postoperative measurements of ET center and ET peak as well as Zernike coefficients. No statistically significant difference was found for the variable of CS. Conclusion: Changes in corneal aberrations after refractive surgery can be attributed to epithelial thickness increase which can be seen in patients that have undergone LASIK.

Long-Term Real-World Outcomes of Corneal Changes in Proliferative Diabetic Retinopathy: Panretinal Photocoagulation vs. Intravitreal Conbercept

PurposeTo compare long-term real-world outcomes of corneal thickness (CT) alterations in proliferative diabetic retinopathy (PDR) patients treated with panretinal photocoagulation (PRP) and intravitreal conbercept (IVC). MethodsThis retrospective study included 69 eyes of 69 patients with PDR (42 PRP and 27 IVC). Full corneal thickness (FCT), corneal epithelial thickness (CET) and corneal stromal thickness (CST) measured by anterior segment optical coherence tomography at baseline were compared between groups. These CT changes at last follow-up from baseline were also compared between groups and within each group. ResultsDuring a mean follow-up of more than two years, the IVC group demonstrated a significantly increased corneal thickness from baseline compared to the PRP group in some areas (PRP vs. IVC: FCT 0-2 mm: -0.59 ± 9.31 vs. 5.59 ± 9.23 μm, p = 0.009; CST 0-2 mm: -2.05 ± 8.79 vs. 3.48 ± 7.52 μm, p = 0.015; CST 2-5 mm: -1.78 ± 13.27 vs. 5.68 ± 14.53 μm, p = 0.046). In within-group comparisons, a significantly increased FCT from baseline was found in the 0-2 mm area in the IVC group (p = 0.004), but no significant change was observed in the PRP group (p = 0.691). For CET changes, a significantly increased CT was observed in the 0-2 mm, 2-5 mm and 5-7 mm areas in both groups respectively (all p < 0.05). Regarding CST, an increased CT was found in the 0-2 mm area in the IVC group (p = 0.037), while a decreased trend was observed in 0-2 mm and 2-5 mm areas in the PRP group (all p > 0.05). ConclusionWhen using PRP or IVC in the long-term management of PDR, CT changes should be considered. This may provide evidence for corneal protection during PDR treatment.

The effects of female sex hormones on the human cornea across a woman’s life cycle

The cornea is a hormone-responsive tissue that responds to changing levels of female sex hormones. This review focuses on the structural and functional changes in the human cornea associated with the hormonal milestones of menarche, pregnancy, and menopause, as well as consequences stemming from the use of exogenous sex hormones for fertility control and replacement. Articles were identified by searching PubMed without language or region restrictions. The primary outcomes evaluated were changes in central corneal thickness (CCT), intraocular pressure (IOP), and quality of the ocular tear film. The potential impact of hormone-associated changes on the diagnosis and surgical management of common eye diseases, as well as the potential use of sex hormones as therapeutic agents is also considered. Understanding the physiological effects of female sex hormones on the cornea is important because that knowledge can shape the management decisions physicians and women face about ocular health across their life stages.

Safety and efficacy of cataract surgery performed with a low-energy femtosecond laser compared with conventional phacoemulsification in Chinese patients: a randomized clinical trial

BackgroundTo compare the safety and efficacy of femtosecond laser-assisted cataract surgery (FLACS) performed with the low-energy FEMTO LDV Z8 (Ziemer Ophthalmic Systems AG, Port, Switzerland) laser compared with conventional phacoemulsification (CP) in Chinese patients.MethodsThis prospective, multicenter, interventional study included 126 patients who were randomized (1:1) to undergo either FLACS or CP followed by intraocular lens (IOL) implantation between January 2019 and April 2020. The primary endpoint included the comparison of the endothelial cell loss (ECL) between the two groups at 3 months. Secondary endpoints included the comparison of cumulative dissipated energy (CDE), change in central corneal thickness (CCT) from baseline, and postoperative uncorrected and corrected distance visual acuities (UDVA and CDVA) in the two groups.ResultsAt all postoperative time points, the FLACS group was found to be non-inferior to CP for the mean ECL (− 409.3 versus − 436.9 cells/mm2 at 3 months) and mean CDE (4.1 versus 4.5 percent-seconds). The increase in CCT was significantly lower in the FLACS group compared with the CP group at Day 7 (4.9 versus 9.2 µm; P = 0.04); however, the difference was not statistically significant at 1 and 3 months. Postoperatively, mean UDVA and CDVA were comparable between the two groups. No intraoperative complications occurred.ConclusionsCataract surgery performed with a low-energy femtosecond laser was non-inferior to CP; however, the FLACS group had a statistically significantly lower increase in CCT at Day 7 compared with CP.Trial registration This trial is registered at ClinicalTrials.gov on May 15, 2019, with trial registration number: NCT03953053.

Corneal Outcomes Following Cataract Surgery Using Ophthalmic Viscosurgical Devices Composed of Chondroitin Sulfate-Hyaluronic Acid: A Systematic Review and Meta-Analysis.

Ophthalmic viscosurgical devices (OVDs) are commonly used during cataract surgery to protect the corneal endothelium. A systematic literature review and meta-analysis were conducted to assess the clinical evidence of OVDs composed of chondroitin sulfate-hyaluronic acid (CS-HA) versus other OVDs in maintaining endothelial cell density (ECD) and corneal thickness (CT). MEDLINE and EMBASE databases were searched from 2000 to 2020. Randomized controlled trials (RCTs, N ≥ 20 per group) comparing an OVD containing CS-HA (ie, VISCOAT®, DuoVisc® or DisCoVisc®) to any other OVD were included. The identified comparators were limited to the OVDs found in the literature, which included those composed of HA-only or hydroxypropyl methylcellulose (HPMC). Outcomes of focus included changes in ECD (baseline to 3 months) and CT (baseline to 24 hours). Meta-analyses were performed using R software, to assess mean differences (MD) in ECD and CT change between CS-HA OVDs and HA-only or HPMC OVDs. A total of 966 abstracts were screened, and data were extracted from 12 RCTs. Meta-analyses using a random-effects model revealed significantly lower percent (%) decrease in ECD for CS-HA OVDs compared to both HA-only (MD: -4.10%; 95% CI: -5.81 to -2.40; p < 0.0001; 9 studies) and HPMC (MD: -6.47%; 95% CI: -10.41 to -2.52; p = 0.001; 2 studies) products. Similarly, % CT increase was significantly lower with CS-HA than with HA-only OVDs (MD: -3.22%; 95% CI: -6.24% to -0.20%; p = 0.04; 4 studies). However, there were no significant differences when comparing % CT change between CS-HA and HPMC OVDs (MD: 2.65%; 95% CI: -0.43% to 0.95%; p = 0.4; 2 studies). CS-HA OVDs lead to less postoperative loss of endothelial cells and may better protect corneal endothelium during cataract surgery, relative to other OVDs. Future randomized studies may be needed to solidify these findings.

Combination of violet light irradiation and collagenase treatments in a rabbit model of keratoconus.

We evaluated the use of collagenase treatment to generate a rabbit model of keratoconus and the impact of violet light (VL) irradiation on the disease model in six Japanese White rabbits. After epithelial debridement, the collagenase group was treated with a collagenase type II solution for 30 min; the control group was treated with a solution without collagenase. Three rabbits also underwent VL irradiation (375 nm, irradiance 310 μW/cm2) for 3 h daily for 7 days after topical collagenase application. Slit-lamp microscopy results, steep keratometry (Ks), corneal astigmatism, central corneal thickness, and axial length were examined before and after the procedure. The corneas were obtained on day 7 for biomechanical evaluation. A significant increase in Ks and corneal astigmatism was observed in the collagenase and VL irradiation groups compared with the control group on day 7. No significant difference was found in the change in corneal thickness between the groups. The elastic modulus at 3, 5, and 10% strain was significantly lower in the collagenase group than in the control group. There was no significant difference in the elastic modulus at any level of strain between the collagenase and VL irradiation groups. The average axial length at day 7 was significantly longer in the collagenase and VL irradiation groups than in the control group. Collagenase treatment induced a model of keratoconus by steepening the keratometric and astigmatic values. There was no significant difference in the observed elastic behavior of normal and ectatic corneas under physiologically relevant stress levels. VL irradiation did not cause regression of corneal steepening in a collagenase-induced model during short-term observation.

Comparison of endothelial cell loss in diabetic patients after conventional phacoemulsification and femtosecond laser-assisted cataract surgery

PurposeThis study aims to comparatively evaluate the morphological changes of the cornea after phacoemulsification (PHACO) and femtosecond laser-assisted cataract surgery (FLACS) without intercurrences in patients with type 2 diabetes mellitus.MethodsA total of 95 diabetic patients with moderate cataracts (N2 + and N3+), 47 undergoing PHACO and 48 undergoing FLACS, were selected randomly for the study. Surgeries were performed by a single surgeon between July 2021 and December 2021. Cumulative dissipated energy (CDE) and total balanced saline solution (BSS) data were obtained at the end of each surgery. Changes in corneal endothelial cell density (ECD) and central corneal thickness (CCT) at three months postoperatively were investigated.ResultsAfter three months, evidence is lacking between groups in the CCT measures; the difference was neither statistically nor clinically relevant. However, for ECD, a significant and clinically significant difference was found; if all patients were treated with laser, the mean ECD would be 423.55 greater (RSE: 86.09; p-value < 0.001; 95% CI: 254.81–592.29) than the ECD potential means of 1656.423 among the conventional group (RSE: 74.90; p-value < 0.001; 95% CI: 1509.62–1803.23).ConclusionsDiabetic patients under treatment with moderate cataracts may predispose themselves to a more significant loss of endothelial cells after conventional phacoemulsification than femtosecond laser-assisted cataract surgery.Trial registrationIt was registered at The Brazilian Registry of Clinical Trials (ReBEC) with the code RBR-6d8whb5 (UTN code: U1111-1277-6020) on 17/05/2022.

Early Visibility of Cellular Aggregates and Changes in Central Corneal Thickness as Predictors of Successful Corneal Endothelial Cell Injection Therapy.

(1) Background: Cell injection therapy is an emerging treatment for bullous keratopathy (BK). Anterior segment optical coherence tomography (AS-OCT) imaging allows the high-resolution assessment of the anterior chamber. Our study aimed to investigate the predictive value of the visibility of cellular aggregates for corneal deturgescence in an animal model of bullous keratopathy. (2) Methods: Cell injections of corneal endothelial cells were performed in 45 eyes in a rabbit model of BK. AS-OCT imaging and central corneal thickness (CCT) measurement were performed at baseline and on day 1, day 4, day 7 and day 14 following cell injection. A logistic regression was modelled to predict successful corneal deturgescence and its failure with cell aggregate visibility and CCT. Receiver-operating characteristic (ROC) curves were plotted, and areas under the curve (AUC) calculated for each time point in these models. (3) Results: Cellular aggregates were identified on days 1, 4, 7 and 14 in 86.7%, 39.5%, 20.0% and 4.4% of eyes, respectively. The positive predictive value of cellular aggregate visibility for successful corneal deturgescence was 71.8%, 64.7%, 66.7% and 100.0% at each time point, respectively. Using logistic regression modelling, the visibility of cellular aggregates on day 1 appeared to increase the likelihood of successful corneal deturgescence, but this did not reach statistical significance. An increase in pachymetry, however, resulted in a small but statistically significant decreased likelihood of success, with an odds ratio of 0.996 for days 1 (95% CI 0.993-1.000), 2 (95% CI 0.993-0.999) and 14 (95% CI 0.994-0.998) and an odds ratio of 0.994 (95% CI 0.991-0.998) for day 7. The ROC curves were plotted, and the AUC values were 0.72 (95% CI 0.55-0.89), 0.80 (95% CI 0. 62-0.98), 0.86 (95% CI 0.71-1.00) and 0.90 (95% CI 0.80-0.99) for days 1, 4, 7 and 14, respectively. (4) Conclusions: Logistic regression modelling of cell aggregate visibility and CCT was predictive of successful corneal endothelial cell injection therapy.

Ten-Year Changes in Vision, Refractive Error, and Corneal Thickness After Descemet Stripping Automated Endothelial Keratoplasty for Fuchs Endothelial Corneal Dystrophy.

The goal of this study was to determine changes in best-corrected visual acuity (BCVA), refractive error, and central corneal thickness (CCT) during the first decade after Descemet stripping automated endothelial keratoplasty (DSAEK). Outcomes of all consecutive eyes undergoing DSAEK for Fuchs endothelial corneal dystrophy (FECD) were reviewed; eyes with untreatable comorbidities before DSAEK were excluded. DSAEK was performed through a temporal incision and all eyes were pseudophakic postoperatively. Changes in BCVA, manifest spherical equivalent, manifest cylinder (vector analysis), and CCT were assessed by using generalized estimating equation models. BCVA improved between 6 months (0.18 ± 0.12 logarithm of the minimum angle of resolution (logMAR); Snellen equivalent, 20/30) and 5 years (0.10 ± 0.10 logMAR; 20/25; n = 74, P < 0.001) and then remained stable at 10 years (0.09 ± 0.10 logMAR, n = 48, P = 0.22). There was a myopic shift of -0.20 ± 0.51 D between 6 months and 5 years (n = 65, P = 0.002) that remained stable at 10 years (-0.09 ± 0.44 D; 20/25; n = 34, P = 0.33). Manifest cylinder drifted with-the-rule between 6 months and 5 years (n = 65, P < 0.001) and between 5 and 10 years (n = 34, P < 0.001). CCT was stable between 6 months (672 ± 57 μm) and 5 years (677 ± 55 μm, n = 67, P = 0.47), but increased at 10 years (702 ± 60 μm, n = 39, P = 0.001). Excellent BCVA can be achieved during the first decade after DSAEK for FECD, although improvement seems to plateau after 5 years. Changes in manifest refractive error were not clinically significant. The gradual increase in CCT was consistent with longer-term changes found after other types of keratoplasty.

Changes in corneal thickness in poorly controlled type-II diabetics after reaching a properly controlled diabetic status

Purpose The aim of this study was to evaluate the corneal thickness changes in the uncontrolled diabetics when proper control was achieved. Design This is a retrospective, randomized, clinical trial. Patients and methods The charts of 198 eyes of 99 uncontrolled diabetic patients (with glycosylated hemoglobin≥7%) were selected using standard random tables. Complete ophthalmologic examination with central corneal thickness (CCT) measurement using the Nidek tonoref III was extrapolated. The glycemic status of the patients was controlled (glycosylated hemoglobin &lt;7%) in a 3-month period. The CCT of all patients was recorded before and after the glycemic control and was compared. Results The mean CCT value of the uncontrolled diabetic patients’ eyes was 531.38±35.56 μm (range=465–602 μm). After achieving the glycemic control, the mean CCT value was 533.95±32.33 μm (range=478–626 μm), with no statistically significant difference (t=−0.524, P=0.601). Conclusion The CCT values did not show any significant change in type-II diabetics after their transit from the uncontrolled to the controlled states.

Corneal Epithelial Thickness Changes After Topical Treatment of Dry Eye Disease in Primary Sjögren Syndrome.

To evaluate the changes on epithelial thickness before and after topical treatment in primary Sjögren syndrome-associated dry eye disease (SS-DED). This was a prospective study that included referred women with SS-DED and healthy age-matched controls. Corneal epithelial thickness was evaluated using high-definition anterior segment optical coherence tomography (Cirrus 5000 HD-OCT) in the baseline first consultation, and four weeks after treatment with preservative free 1mg/1mL sodium hyaluronate. Schirmer test 1 (ST1), tear break-up time (TBUT), tear meniscus height (TMH), SICCA Ocular Surface Score (SICCA OSS) and Ocular Surface Disease Index (OSDI) were evaluated. Statistical significance was defined as p-value <0.05. The study included 40 eyes, 20 with SS-DED and 20 controls. At baseline, SS-DED patients had lower ST1 (11.1 ± 2.2mm vs 14.1 ± 3.1mm, p<0.01), faster TBUT (9.1 ± 1.8s vs 13.2 ± 1.1s, p<0.01) and lower TMH (211.2 ± 68.4 µm vs 217.2 ± 60.1µm; p<0.01) than the control group, whereas SICCA OSS and OSDI were higher (p<0.01). The superior epithelium was thinner in SS-DED group (41.1 ± 3.2 µm vs 43.1± 2.3 µm, p<0.01). After treatment, ST1, TBUT, TMH, SICCA OSS, and OSDI improved (p<0.01), and superior epithelium thickened (p<0.01) in the SS-DED group. Treatment with sodium hyaluronate improved ST1, TBUT, TMH, SICCA-OSS, and OSDI score. Superior epithelium tends to be thinner in SS-DED but becomes thicker with treatment. Our results seem to illustrate the morphological changes in the corneal epithelium in DED, which could be further recognized as a clinical biomarker of SS-DED.

Central Corneal Thickness and Intraocular Pressure Changes Post- Phacoemulsification Surgery in Glaucoma Patients with Cataract

To compare the changes of central corneal thickness (CCT) and intraocular pressure (IOP) post-phacoemulsification between cataract patients with and without pre-existing glaucoma. A prospective cohort study of 86 patients with visually significant cataract: 43 with pre-existing glaucoma (GC group) and 43 without pre-existing glaucoma (CO group). CCT and IOP were evaluated at baseline (pre-phacoemulsification), as well as at 2 hours, 1 day, 1 week and 6 weeks post-phacoemulsification. The GC group have significantly thinner CCT pre-operatively (p = 0.003). There was a steady increase of CCT with the highest peak at 1 day post-phacoemulsification, followed by a steady decline of CCT and back to baseline at 6 weeks post-phacoemulsification in both groups. The GC group demonstrated a significant difference in CCT at 2 hours (mean difference 60.2 μm, p = 0.003) and 1 day (mean difference 70.6 μm, p = 0.002) post-phacoemulsification, compared to the CO group. There was a sudden increase in IOP at 2 hours post-phacoemulsification measured by GAT and DCT in both groups. This was followed by a gradual reduction of IOP, with significant reduction at 6 weeks post-phacoemulsification in both groups. However, there was no significant difference in IOP between the two groups. IOP measured by GAT and DCT showed strong correlation (r &gt; 0.75, p &lt; 0.001) in both groups. There was no significant correlation between GAT-IOP and CCT changes; nor between DCT-IOP and CCT changes in both groups. CCT changes post-phacoemulsification in patients with pre-existing glaucoma were similar, in spite of having thinner CCT pre-operatively. IOP measurement was not affected by CCT changes in glaucoma patients post-phacoemulsification. IOP measurement using GAT is comparable with DCT post-phacoemulsification.

Corneal Epithelial Remodeling in a 6-Month Follow-up Period in Myopic Corneal Refractive Surgeries

To investigate corneal epithelial thickness changes during a 6-month follow-up period after transepithelial photorefractive keratectomy (tPRK), femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK), and small incision lenticule extraction (SMILE). This prospective study included 76 eyes of 76 participants who underwent myopic refractive surgery (23 FS-LASIK, 22 SMILE, and 31 tPRK). Epithelial thickness and anterior curvature were averaged over 4 regions (subdivided into 25 areas) and measured by spectral-domain optical coherence tomography and Scheimpflug tomography before the operation (pre) and at 1 or 3 days (pos1-3d), 1 week (pos1w), and 1 month (pos1m), 3 months (pos3m), and 6 months (pos6m) postoperatively. The epithelial thickness of the three groups was similar in both the pre and pos6m (all P > .05), but the tPRK group fluctuated the most during the follow-up period. The largest increase was in the inferior-temporal paracentral area (7.25 ± 2.58 μm for FS-LASIK; 5.79 ± 2.41 μm for SMILE; 4.88 ± 5.84 μm for tPRK; all P < .001). Only the epithelial thickness of tPRK increased from pos3m to pos6m (P < .05), whereas all changes for FS-LASIK and SMILE were not significant (P > .05). A positive correlation of thickness changes with curvature gradient in the paracentral region of tPRK was found (r = 0.549, P = .018), but not in other regions in all groups. Epithelial remodeling followed different trends after different surgeries from the early postoperative stage onward, but exhibited similar values at pos6m. Although remodeling after FS-LASIK and SMILE stabilized by pos3m, it remained unstable at pos6m after tPRK. These changes may affect corneal profile and lead to deviation from the intended surgical outcome. [J Refract Surg. 2023;39(3):187-196.].

Corneal Ectasia detection by epithelium pattern standard deviation from optical coherence tomography.

To test the ability of the corneal epithelial pattern standard deviation to distinguish between normal and cases with corneal ectatic condition. Instituto de Olhos Renato Ambrósio, Rio de janeiro, Brazil. Cross-sectional retrospective study. Patients were stratified into four groups based on clinical data and. (Groups 1 and 2 comprised one eye randomly selected from 105 patients with normal corneas (N) and 86 patients with bilateral keratoconus (KC). Groups 3 and 4, respectively comprised 11 ectatic eyes with no surgical treatment for keratoconus (VAE-E) from patients whose fellow eyes (61) presented with normal topographic patterns (VAE-NT). Corneas were scanned using an OCT system (RT Vue) and Scheimpflug corneal tomography (Pentacam), and also had biomechanical assessment through the Corvis ST. Corneal epithelial thickness maps were analyzed and the pattern standard deviation (PSD) value was calculated. The area under the ROC curve analysis was used to evaluate the diagnostic accuracy of the indices. Epithelial PSD was significantly different across the four groups (p<0.0001). The pairwise comparison revealed that the normal group presented significantly lower values than both ectasia groups (KC and VAE-E, p<0.0001) and the VAE-NT group (p=0.0008). There was no significant difference between KC and VAE-E (p=0.4284), while they were significantly higher than the VAE-NT group (p<0.0001 and p=0.0004). Epithelial PSD can be used to detect abnormal epithelial thickness patterns. Corneal epithelial thickness changes could be detected accurately in keratoconus patients, even in the form fruste of the disease.

Real-time corneal thickness changes during phacoemulsification cataract surgery.

To observe the changes in corneal thickness during phacoemulsification cataract surgery and to analyze the influencing factors. One hundred two patients (102 eyes) with cataracts undergoing phacoemulsification cataract surgery at Shandong Eye Hospital between July and October 2021 were included. Intraoperative OCT was applied to capture real-time images preoperatively, before and after ultrasonic emulsification, at the end of irrigation aspiration and the end of surgery. Then, the corneal thickness at the above time points was measured using Photoshop software. The corneal thickness of 102 cataract patients was 511.79 ± 31.46μm before operation and 512.71 ± 31.51μm at the beginning of phacoemulsification, which increased by 0.91 ± 1.48μm (0.2%). At the end of ultrasonic emulsification, the corneal thickness was 521.58 ± 32.75μm and 8.87 ± 8.71μm (1.7%) thicker than that before the procedure. After irrigation aspiration, the corneal thickness reached 528.09 ± 33.87μm, which increased by 6.52 ± 6.38μm (1.3%) compared with that of the previous step. At the end of the operation, the corneal thickness was 539.19 ± 33.88μm, 11.09 ± 10.92μm, and 27.37 ± 13.64μm thicker than that of the previous step and the preoperative thickness, respectively, with an overall increase of 5.3%. The differences were statistically significant at all time points (all P < 0.001). Correlation analysis showed that postoperative corneal thickness changes were correlated with age, cataract lens nuclear grade, actual phacoemulsification time (APT), effective phacoemulsification time (EPT), average phacoemulsification energy (APE), total surgery time (TST), cell density (CD), maximum cell area (MAX), and cell area standard deviation (SD) (all P < 0.05), while the changes in thickness were not correlated with gender, cell area coefficient of variation (CV), percentage of hexagonal cells (6A), average cell area (AVE), or minimum cell area (MIN) (all P > 0.05). During phacoemulsification cataract surgery, corneal thickness gradually increases in real time with the increase of perfusion pressure and intraocular manipulation time. The real-time magnitude of intraoperative corneal thickness change is closely related to lens nucleus hardness, corneal endothelial cell density, ultrasound energy, and time for emulsification.

Outcomes of primary surgical treatment of medically recalcitrant post-keratoplasty glaucoma with transscleral cyclophotocoagulation.

To report the outcomes of slow-coagulation continuous-wave transscleral cyclophotocoagulation (CW-TSCPC) in post-keratoplasty glaucoma refractory to medical therapy. Medical records of 47 patients (mean age of 70.7 ± 15.7 years and follow-up of 13.9 ± 7.1 months) were retrospectively enrolled. All patients had the diagnosis of secondary glaucoma after penetrating keratoplasty (PKP; n = 28) or Descemet's stripping automated endothelial keratoplasty (DSAEK; n = 19) with no previous history of incisional glaucoma or TSCPC surgeries. Study participants underwent slow-coagulation CW-TSCPC (1250-milliwatt power and 4-second duration). A statically significant reduction of IOP from 31.8 ± 8.0 mmHg preoperatively to 16.9 ± 9.0 mmHg postoperatively was noted (p < 0.001). Similarly, the number of glaucoma medications decreased from 4.0 ± 1.0 to 2.7 ± 1.4 (p < 0.001). The overall success rates at 12 and 24 months were 68.1% and 66.0%, respectively, with no difference in success rates between post-PKP and post-DSAEK subgroups (p = 0.836). No significant changes in VA or central corneal thickness (CCT) were observed (p = 0.345 and 0.311, respectively). One (3.3%) patient had a graft rejection. The majority of the complications noted during this study were mild and transient. Our study suggests that slow-coagulation TSCPC may be a safe and efficient surgical glaucoma treatment modality in patients with medically uncontrolled post-keratoplasty glaucoma.