Evaluation of Choroidal Vascularity Index in Keratoconus Patients: Does Choroidal Vascularity Change in Keratoconus?

Purpose: To investigate the choroidal structure in keratoconic patients with different severity using the choroidal vascularity index (CVI) derived from image binarization on enhanced depth imaging optical coherence tomography scans (EDI-OCT). Methods: Sixty-eight eyes from 34 keratoconus (KCN) patients and 72 eyes from 36 healthy subjects were recruited in this prospective, noninterventional, comparative cross-sectional study. EDI-OCT was employed to measure choroidal parameters, including choroidal thickness (CT), total choroidal area (TCA), luminal area, stromal area, and CVI. Results: Subfoveal CT was 354.6 ± 66.8 µm in the control group and 371 ± 64.5 µm in the KCN group (P = 0.86). There was no significant difference between control and KCN groups in terms of TCA (0.66 ± 0.14 mm2 vs. 0.7 ± 0.12 mm2; P = 0.70), luminal area (0.49 ± 0.10 mm2 vs. 0.53 ± 0.08 mm2; P = 0.67), and stromal area (0.16 ± 0.05 mm2 vs. 0.17 ± 0.05 mm2; P = 0.84). CVI was also comparable in the control group (75.4% ±3.4%) and the KCN group (75.6% ±4.5%; P = 0.43). There was also no significant correlation between other choroidal parameters and KCN severity indices. Conclusion: It seems that CVI as well as other choroidal biomarkers were not significantly different between patients with KCN and healthy subjects.

Effects of Descemet Stripping Automated Endothelial Keratoplasty on Corneal Densitometry of Cases with Long-Standing Pseudophakic Bullous Keratopathy.

Purpose: To quantify the effects of Descemet stripping automated endothelial keratoplasty (DSAEK) on corneal clarity and densitometry of patients with long-standing pseudophakic bullous keratopathy (PBK) complicated with subepithelial fibrosis. Methods: Thirty-four eyes with PBK complicated with corneal edema for more than 6 months and subepithelial fibrosis were enrolled. All subjects underwent complete ophthalmic examination and corneal densitometry module of Pentacam HR, before and 1, 3, and 6 months after DSAEK. Results: Thirteen patients were excluded due to postoperative complications or missed to follow-up visits. Finally, twenty-one patients' data were analyzed. Corneal densitometry measures significantly decreased in all three layers (anterior, central, and posterior) 3 and 6 months after surgery compared to preoperative values; however, the differences did not reach statistical significance in the 1st month. Moreover, densitometry measurements were significantly lower at month 6 compared to month 1, but not at month 3 compared to month 1. Corneal densitometry of the anterior layer was significantly higher than central and posterior layers in 2 mm and 6 mm zones preoperatively and at all postoperative visits. Corneal light backscatter of each three layers was not statistically different between 0-2 mm and 2-6 mm in all pre- and postoperative visits. Conclusions: Corneal densitometry in cases of PBK begins to improve after DSAEK in different layers in a slow and continued trend which takes up to 6 months for an effect to be seen. Interestingly, this improvement is possible even in complicated corneas with long-standing edema. Hence, corneal densitometry can be used as an objective method for quantification of the outcome of DSAEK in complicated cases of PBK.

Role of Different Types of Contact Lenses in Epithelial Thickness.

OBJECTIVE: To evaluate the potential role of different types of contact lenses, such as soft (SCL), hard (HCL), and mini scleral (SCCL), in corneal epithelial thickness with anterior segment optical coherence tomography (AS-OCT). METHODS: In this cross-sectional study, patients who used contact lens at recent 6 months were recruited consecutively from September 2019 to October 2019, and the epithelial thicknesses of the cornea were obtained by AS-OCT and compared with control subjects who did not use contact lens. RESULTS: In total, 184 eyes (115 subjects) were included; of them, 75 eyes were keratoconic (KCN) and 109 eyes were nonkeratoconic (non-KCN). Twenty eyes in KCN and 79 eyes of non-KCN group had no history of contact lens use and were included for comparison with KCN and non-KCN contact lens users, respectively. Mean duration of contact lens wearing was 75.63±50.42 months. The epithelial thickness of non-KCN SCL group was thinner than that of non-KCN control subjects all over the cornea, whereas the epithelium of non-KCN HCL was thinner at central site as well as nasal and temporal paracentral and midperipheral areas. Epithelial thickness of the KCN HCL group was not different from the KCN control subjects in all sectors. The KCN SCCL group had thinner epithelium at nearly all peripheral sectors as well as inferior, inferotemporal, inferonasal, and nasal midperipheral sectors compared with KCN control subjects. CONCLUSION: The corneal epithelium was thinner at the peripheral zones in KCN SCCL users; at both peripheral and central zones in non-KCN SCL users and in central zones in non-KCN HCL users.

Clinical outcomes of transepithelial photorefractive keratectomy with epithelial ablation targeting actual epithelial thickness vs default laser platform values.

PURPOSE: To investigate the clinical outcomes of transepithelial photorefractive keratectomy (tPRK) with actual epithelial thickness vs default software values. SETTING: Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. DESIGN: Prospective controlled study. METHODS: Patients with refractive spherical error of -1.50 to -7.00 diopters (D) and refractive astigmatism up to 4.00 D were consecutively enrolled and divided into 2 groups: group 1 undergone tPRK with actual central and peripheral epithelial thickness input in right eyes, group 2 undergone tPRK with actual central and 10 mm higher peripheral epithelial thickness in right eyes. Left eyes in both groups underwent tPRK with default protocol. Outcome measures were induced refractive error, achieved optical zone (OZ), and wasted stromal tissue. RESULTS: 83 patients were included in this study. Mean ± SD of induced spherical equivalent was +0.15 ± 0.39 D and +0.01 ± 0.35 D in right and left eyes of group 1 (P = .01) and +0.04 ± 0.22 D and +0.03 ± 0.23 D in right and left eyes of group 2 (P = .75), respectively. There was no statistically significant difference between wasted tissue between right and left eyes in group 1 and group 2 (P = .77 and P = .49, respectively). OZ contraction was significantly higher in right compared with left eyes in group 1 (P = .05), but not in group 2 (P = .95). CONCLUSIONS: In tPRK, refractive outcomes, wasted tissue, and OZ contraction depend little on preexisting corneal epithelial thickness in corneas with normal range epithelial thickness. However, OZ contraction may be a concern in lower amount of ablations.

Effect of venting incisions on graft attachment in Descemet's stripping automated endothelial keratoplasty.

PURPOSE: To investigate the impact of venting incisions on the adherence of graft to the recipient's stroma in Descemet's stripping automated endothelial keratoplasty (DSAEK). METHODS: Fifty-six patients were enrolled in this study. Patients were randomly allocated into two groups. Twenty-eight patients had a DSAEK procedure with venting incisions. The second group was treated by conventional DSAEK with no venting incisions. Slit-lamp examination and anterior segment optical coherence tomography (AS-OCT) were performed in day one and 14 days after surgery to investigate graft attachment. The thickness of cornea and lenticle were also evaluated by AS-OCT. BCVA (logMAR) was measured the day before the surgery and 14 days postoperatively. RESULTS: Subclinical graft detachment in the first day after surgery was significantly lower in patients who had a DSAEK procedure and venting incisions (P = 0.02), but no difference was noted in the rate of clinical graft detachment on day one (P = 0.24) and subclinical and clinical graft detachment on day 14 (P = 0.24, P = 0.50, respectively). The thickness of the cornea and lenticle after the surgery were statistically similar between the two groups (P = 0.903, P = 0.402, respectively). No difference in the improvement of BCVA was observed between the venting and non-venting group (P = 0.143). CONCLUSIONS: Routine use of venting incisions may not be necessary in the standard DSAEK procedures. More studies with larger sample sizes are needed to better confirm the results of this study.

3D-Printed membrane as an alternative to amniotic membrane for ocular surface/conjunctival defect reconstruction: An in vitro & in vivo study.

BACKGROUND: The aim of this study was to evaluate the surgical handling and clinical applicability of a specific 3D-printed membrane design fabricated using a gelatin, elastin and sodium hyaluronate blend for conjunctival reconstruction and compare it with amniotic membrane (AM), which is normally used in such surgeries. METHODS: 3D printing technique was employed to fabricate the membrane based on gradient design. Prior to printing, rheometry was employed to optimize the ink composition. The printed membranes were then fully characterized in terms of physical and mechanical properties. In vitro viability, proliferation and adhesion of human limbal epithelial cells were assessed using MTT assay and scanning electron microscopy (SEM), respectively. Prior to in vivo experiment, surgical handling of each membrane was evaluated by three surgeons. In vivo evaluation was conducted through implanting the gelatin-based membranes and AM on induced conjunctival defects in rabbits (n = 8). Clinical observations, including epithelialization, inflammation severity, scar tissue formation and presence of granulation tissue, were recorded from day 1 through day 28. Histological examination was performed on all enucleated eyes on day 28. In addition to H&E staining, specific stains including Periodic Acid Schiff staining, Masson's Trichrome staining and immuno-histochemical staining for α-SMA were further used to assess goblet cell proliferation, healed sub-epithelial stroma and scar tissue formation and the presence of myofibroblasts, respectively. RESULTS: Among all the examined compositions, a blend of 8% w/v gelatin, 2% w/v elastin and 0.5% w/v sodium hyaluronate was found to be appropriate for printing. The printed membranes had favorable optical characteristics (colorless and transparent), and the surgical handling was significantly easier compared to AM. Epithelial cells cultivated on the membranes indicated suitable viability and proliferation, and SEM images presented appropriate cell adhesion on the surface of the membranes. Clinical observations suggested similar epithelialization time (approximately 3 weeks) for both the membrane and AM grafted eyes but significantly lower levels of clinical inflammation in the membrane group from day 1 through day 28 (p = 0.01), which is a key advantage of using the printed membranes over the AM. Histological examination showed similar qualities in the healed epithelium in terms of cell morphology and cell layers. However, twice the density of goblet cells per 100 cells was observed in the gelatin-based membrane grafted group. Remnant of the degraded implant was seen in only 3 of the membranes, but in 7 of the AM grafted eyes. Inflammation and granulomatous reaction was significantly higher in sections containing the AM compared to membrane (p < 0.01 and p = 0.01, respectively). α-SMA staining was more evident, but not significantly different from the gelatin-based membrane, for the AM group (p = 0.25). CONCLUSION: The designed gelatin-based membrane offers the necessary physical and mechanical characteristics needed for successful ocular surface/conjunctival defect construction and may be considered a promising alternative to AM due to a more predictable degradation pattern, higher goblet cell density on the healed epithelium, less inflammation and reduced scar tissue formation.

Selective Localized Tenonplasty for Corneal Burns Based on the Findings of Ocular Surface Fluorescein Angiography.

PURPOSE: To report the results of a selective localized tenonplasty procedure based on findings of ocular surface fluorescein angiography (FA). METHODS: Six consecutive patients with severe chemical burns were included in this study. Using fluorescein angiogram images, patients underwent selective localized tenonplasty to cover the identified ischemic areas in FA. RESULTS: FA 1 week after surgery showed a perfused ocular surface in all eyes except for 1 quadrant of limbal ischemia in 1 eye. After the second tenonplasty, recirculation was also detected in that quadrant. None of the eyes perforated during the follow-up period. CONCLUSIONS: We observed acceptable outcomes in our patients after selective tenonplasty based on ocular surface angiography.

Femtosecond laser arcuate keratotomy for the correction of postkeratoplasty high astigmatism in keratoconus.

BACKGROUND: Astigmatism is the leading complication in visual recovery after penetrating keratoplasty (PKP) and deep anterior lamellar keratoplasty (DALK); in this study, we evaluated the outcome of femtosecond laser arcuate keratotomy (FLAK) after DALK and PKP in Iranian keratoconic patients. MATERIALS AND METHODS: In this prospective interventional case series, refractive and keratometric predictability, efficacy, and complications of FLAK for postkeratoplasty astigmatism in keratoconus were evaluated; 23 eyes of 23 consecutive patients (mean age of 32.43 ± 9.11 years) with high astigmatism were enrolled. The femtosecond laser performed paired 90°-angled arcuate incisions. RESULTS: Mean logarithm of the minimum angle of resolution of corrected and uncorrected visual acuity improved from preoperative values of 0.30 ± 0.18 and 0.85 ± 0.32 to 6-month values of 0.19 ± 0.17 and 0.65 ± 0.33, respectively (P < 0.05). Mean subjective astigmatism was 7.79 ± 2.64 diopter (D) preoperatively and 3.69 ± 2.25D at 6-month after surgery (P < 0.05). Surgically induced astigmatism was 9.27 ± 5.00D. Mean refractive spherical equivalent showed no significant (P = 0.69) hyperopic shift from - 4.21 ± 4.84D preoperatively to - 2.16 ± 6.09D postoperatively. Two (8.7%) microperforations were observed. CONCLUSION: FLAK is a relatively safe and effective method for the treatment of postkeratoplasty astigmatism.

Mini-scleral Contact Lens for Management of Poor Visual Outcomes after Intrastromal Corneal Ring Segments Implantation in Keratoconus.

PURPOSE: To evaluate the feasibility and efficacy of mini-scleral design (MSD) contact lenses to treat keratoconus patients who were unsatisfied with the results of corneal inlay. METHODS: In this prospective interventional case series, 9 eyes of 6 keratoconus patients who were unsatisfied with the results of corneal inlay were fitted with MSD contact lenses. Demographic data, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and higher order aberrations (HOAs) were evaluated before contact lens fitting. Corrected visual acuity by placing the MSD contact lens with or without over-refraction, and HOAs were measured one hour after contact lens fitting. One month after contact lens wearing, corrected visual acuity by placing the MSD contact lens with over-refraction and possible contact lens related problems were assessed. Ocular comfort and contact lens handling problems were asked in follow-up visits. The data was analyzed using descriptive statistical tests. RESULTS: Nine eyes of 6 patients were successfully fitted with the mini-scleral lens. Fitting was ideal in 7 eyes and acceptable in 2 eyes. Mean corrected visual acuity by placing the MSD lens without over-refraction was 0.09 (range, 0.00-0.15) LogMAR which was significantly better than the mean BSCVA of 0.38 (range, 0.2-0.6) LogMAR (P = 0.007). The mean root mean square (RMS) of third-order coma and trefoil significantly decreased after MSD contact lens fitting (P = 0.012 and P = 0.015, respectively); however, changes in the fourth-order spherical aberration were not statistically significant (P = 0.336). CONCLUSION: Mini-scleral contact lenses may be helpful in the management of visually unsatisfied patients after corneal inlay.

Comparison of Lotrafilcon B and Balafilcon A silicone hydrogel bandage contact lenses in reducing pain and discomfort after photorefractive keratectomy: A contralateral eye study.

PURPOSE: To assess the effect of two silicone hydrogel contact lenses with high oxygen permeability in patients having photorefractive keratectomy (PRK). SETTING: Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. METHODS: Sixty patients (120 eyes) who had bilateral PRK were enrolled in this double blind clinical trial. Each patient was fitted with a Lotrafilcon B (Air Optix(®)AQUA, Ciba Vision, Duluth, GA, USA) lens in one eye and a Balafilcon A (PureVision™ Bausch & Lomb, Rochester, NY, USA) lens in the fellow eye. Patients' responses to a subjective questionnaire in terms of pain, foreign body sensation, photophobia, blurred vision and epiphora were evaluated on the first and third postoperative days. RESULTS: Mean pain score for Lotrafilcon B and Balafilcon A contact lenses was 4.43±3.18 vs. 5.45±3.37 on the first postoperative day and 3.43±3.23 vs. 3.88±3.01 on the third postoperative day. However, the difference was only significant in the first 24h after surgery (P=0.032). Foreign body sensation was clinically higher with Balafilcon A contact lens (5.0±3.47 vs. 4.08±3.34 on day 1 and 4.98±3.52 vs. 3.55±3.20 on day 3) and the difference was statistically significant on the first and the third postoperative days (P=0.042 and 0.002, respectively). There was no statistically significant difference between two contact lenses in terms of photophobia, epiphora and blurred vision (P>0.05). CONCLUSION: The Lotrafilcon B lens resulted in significantly less postoperative pain and discomfort after PRK, especially in the first 24h after PRK.

Prevention of corneal neovascularization: comparison of different doses of subconjunctival bevacizumab with its topical form in experimental rats.

BACKGROUND: To compare the effect of different dosages of subconjunctival bevacizumab with its topical administration on preventing the development of corneal neovascularization (CNV) in a rat model of corneal chemical injury. METHODS: Neovascularization was induced by pressing a 2-mm diameter alkaline-coated applicator on the central cornea of the right eye of 50 anesthetized male rats. Immediately after cauterization, rats were divided randomly into 5 groups. Groups 1-4 received a subconjunctival injection of 0.02 ml of normal saline (control) or 1, 5 and 25 mg/ml of bevacizumab, respectively. In the fifth group, topical bevacizumab was instilled daily for 7 consecutive days. After 7 days, digital photographs of the cornea were taken and the area of the neovascularized cornea was calculated. RESULTS: Analysis of digital photographs showed that, compared with the controls, a single subconjunctival injection of at least 0.1 mg of bevacizumab (5 mg/ml) - immediately after corneal cauterization - effectively decreased CNV after 7 days. Injection of 25 mg/ml of bevacizumab in the fourth group increased the avascular area more than twofold, compared with the saline-treated group (32.2% compared with 15%, p < 0.001). This difference between groups 4 and 2 was statistically significant (p = 0.04). Although topical delivery of 25 mg/ml bevacizumab was effective to inhibit CNV (p = 0.004), the results were similar to those of the third group. Qualitative microscopic evaluation of the cornea was compatible with the gross findings, as bevacizumab-treated groups had less intense corneal vessel channels and inflammation. CONCLUSION: Both subconjunctival and topical bevacizumab can prevent CNV in rats.

Deep intrastromal bevacizumab injection for management of corneal stromal vascularization after deep anterior lamellar keratoplasty, a novel technique.

PURPOSE: To report the effect of intrastromal injection of bevacizumab in an eye with extensive corneal stromal vascularization after deep anterior lamellar keratoplasty. METHODS: Bevacizumab (2.5 mg/1 mL) was injected into the deep corneal stroma of an eye with severe and extensive stromal vascularization. RESULTS: Corneal vascularization regressed dramatically after deep stromal injection of bevacizumab with no recurrence after 6 months. Visual acuity was improved, and the patient's complaints subsided. CONCLUSIONS: Corneal intrastromal injection of bevacizumab can be considered for management of intrastromal vascularization after deep anterior lamellar keratoplasty.

Efficacy of intralesional bevacizumab injection in decreasing pterygium size.

PURPOSE: To evaluate the efficacy of intralesional bevacizumab injection in decreasing size of pterygium. METHODS: Seventeen patients with pterygium (14 with primary and 3 with recurrent pterygium) received intralesional injections of bevacizumab (2.5 mg/0.1 mL). Digital photographs were analyzed by image analysis software to determine the change of corneal involvement as a percentage of the total corneal surface. RESULTS: The mean age of the patients was 45.5 ± 15.8 years. The mean percentage size of lesions before injection was 17.2% ± 4.3% of corneal surface. The mean percentage size of lesions 1 week, 1 month, and 3 months after injection was 15.1% ± 4.3%, 13.4% ± 4.0%, and 14.1% ± 4.4% of corneal surface, respectively. The mean percentage decrease of lesion size was 3.97% ± 3.84%. There were statistically significant differences between percentage of lesion size before and 1 week (P < 0.001), 1 month (P < 0.001), and 3 months (P < 0.001) after injection of bevacizumab. There were neither postinjection ocular complications such as rise of intraocular pressure nor systemic adverse events. Visual acuity did not change after injection of bevacizumab. Despite statistically significant decrease in pterygium size, this decrease does not seem to be clinically significant. CONCLUSIONS: Intralesional bevacizumab injection is fairly effective in reducing the size of pterygium and is well tolerated; however, this effect is not clinically significant.

Prevention and treatment of corneal neovascularization: comparison of different doses of subconjunctival bevacizumab with corticosteroid in experimental rats.

BACKGROUND: To evaluate and compare the effect of different doses of subconjunctival bevacizumab with betamethasone on the development of corneal major new vessels in a rat model of corneal chemical injury. METHODS: The right eyes of 100 male Sprague-Dawley rats were randomly divided into 10 experimental groups (n = 10 per group). Chemical cauterization of the cornea was performed by using silver nitrate/potassium nitrate sticks. Immediately following corneal cauterization, the animals in groups 1-5 received subconjunctival injections of 0.02 ml of normal saline (control A), betamethasone LA (6 mg/ml) and different doses of bevacizumab (1, 5 and 25 mg/ml), respectively. In another experiment, the animals in groups 6-10 received subconjunctival injections of 0.02 ml of normal saline (control B), betamethasone LA (6 mg/ml) and different doses of bevacizumab (1, 5 and 25 mg/ml), respectively, 7 days following corneal cauterization. The numbers of major thick-walled vessels originating from the limbus reaching the corneal scar were counted 7 days after corneal cauterization in groups 1-5 and 14 days after corneal cauterization in groups 6-10. RESULTS: The number of major vessels in groups 1-5 was 19.63 +/- 3.77, 17.25 +/- 5.33, 16.10 +/- 5.02, 12.89 +/- 2.70 and 12.36 +/- 4.45 when assessed 7 days after corneal cauterization, respectively. Administration of betamethasone in group 2 had no significant effect on the corneal major vessel count compared to control A. The number of major vessels in groups 4 and 5 (bevacizumab 5 and 25 mg/ml) was significantly lower than that of group 1 (p < 0.01, Student's t test). The number of vessels in groups 6-10 was 12.55 +/- 5.64, 11.30 +/- 9.33, 5.50 +/- 6.34, 2.73 +/- 4.73 and 2.67 +/- 3.77 when assessed 14 days after corneal cauterization, respectively. Subconjunctival administration of betamethasone 7 days after corneal cauterization did not reduce the amount of corneal major vessels compared to control B. Administration of 0.02 ml of bevacizumab in doses of 1, 5 and 25 mg/ml 7 days after corneal cauterization significantly reduced the amount of major vessels compared to group 6 (p = 0.01, p < 0.01 and p < 0.01, respectively). There was no significant difference in percent area of corneal scar between different groups. CONCLUSION: Single subconjunctival injection of bevacizumab is efficacious in the prevention of formation as well as regression of major vessels compared to betamethasone in this rat model of corneal neovascularization. Even lower doses of bevacizumab might be efficacious.

Topical mitomycin-C for treatment of partially-excised ocular surface squamous neoplasia.

BACKGROUND: This study was conducted to determine the treatment outcome of incompletely removed, histopathologically documented ocular surface squamous neoplasia with mitomycin-C. METHODS: Through an interventional case series, 17 eyes of 17 patients presented with incompletely removed ocular surface squamous neoplasia were treated according to a protocol using two to three alternate seven-day courses of 0.04% mitomycin-C. Clinical recurrence was re-treated with the same protocol. All patients had weekly follow-up visits to the end of the treatment course, then biweekly visits for three months, and monthly visits, thereafter. RESULTS: The mean+/-SD follow-up period was 30.76+/-4.4 (range: 24.5 - 41) months. Five patients (29.4%) experienced recurrence after the initial treatment; four of them responded to retreatment and were disease-free till the end of follow-up. Survival analysis with Kaplan-Meier method was performed. Taking into account four recurrences, the 41-month nonrecurrence rate was 70.6%. However, including four of five patients with recurrence who responded to retreatment, the final outcome in survival analysis was 94.1% nonrecurrence for 41 months of follow-up. All patients reported mild to moderate redness and irritation which were controlled with lubricants and mild corticosteroid eye drops. No serious ocular or systemic side effects were observed. CONCLUSION: Point zero four percent (0.04%) mitomycin-C drop used as two to three alternate seven-day courses seems to be a safe and effective treatment for ocular surface squamous neoplasia.