Efficacy and Safety of the Modified Cretan Protocol in Patients with Post-LASIK Ectasia

Objectives: To investigate the clinical efficacy and safety of the modified Cretan protocol in patients with post-laser in situ keratomileusis ectasia (PLE). Materials and Methods: In this retrospective study, 26 eyes of 16 patients with PLE were treated with the modified Cretan protocol (combined transepithelial phototherapeutic keratectomy and accelerated corneal collagen cross-linking). Visual, refractive, tomographic, and aberrometric outcomes and point spread function (PSF) were recorded preoperatively and at 6, 12, and 24 months after treatment. Results: Both uncorrected and best corrected visual acuity were stable at 24 months postoperatively compared to baseline (from 0.89±0.36 to 0.79±0.33 logarithm of the minimum angle of resolution [LogMAR] and 0.31±0.25 to 0.24±0.19 LogMAR, respectively, p>0.05 for all values). The mean K1, K2, Kmean, thinnest corneal thickness, and spherical aberration at baseline were 45.76±5.75 diopters (D), 48.62±6.17 D, 47.13±5.89 D, 433.16±56.86 µm, and -0.21±0.63 µm respectively. These values were reduced to 42.86±6.34 D, 45.92±6.74 D, 44.21±6.4 D, 391.07±54.76 µm, and -0.51±0.58 µm at 24 months postoperatively (p<0.001, p=0.002, p<0.001, p=0.001, and p=0.02, respectively). The mean spherical equivalent, manifest cylinder, Kmax, central corneal thickness, other corneal aberrations (root mean square, trefoil, coma, quatrefoil, astigmatism), and PSF remained stable (p>0.05 for all variables), while anterior and posterior elevation were significantly improved at 24 months postoperatively (p<0.001 and p=0.02, respectively). No surgical complications occurred during the 24-month follow-up. Conclusion: The modified Cretan protocol is a safe and effective treatment option for PLE patients that provides visual stabilization and significant improvement in topographic parameters during the 24-month follow-up. Further studies are needed to support our results.

A Review of the Categorizations of Mild, Moderate, and Severe Bacterial Keratitis Ulcers and Day-1 Treatment Regimen When Using the Topical Fluoroquinolones 0.3% Ciprofloxacin and 0.3% Ofloxacin.

Background: There are published suggestions that bacterial keratitis (BK) can be classified as mild, moderate, or severe and that the day-1 antibiotic drop regimen may differ for each category using the topical second-generation fluoroquinolones 0.3% ciprofloxacin and 0.3% ofloxacin (2FQ). The classification criteria are not consistently defined and the suggested regimens are often unreferenced and so here, the evidence base for applying such regimens in clinical practice is examined. Objective: To examine the evidence base regarding the categorization criteria used for BK and determine whether any evidence exists to support suggestions that different day-1 treatment regimen using the 2FQ may be applied based on any assigned categorization. Methods: The literature on BK treatment was reviewed, as were the clinical studies involving the commercially available 2FQ. All statements pertaining to classification and treatment paradigms involving BK were then collated and reviewed, as were the methodologies employed in the 2FQ clinical studies. Results: There have been no clinical trials using the 2FQ, or indeed any other topical antibiotics, which have used different day-1 drop regimen depending on the size, depth, and location of the ulcer or for ulcers classified as mild, moderate, or severe. Thus, there is no evidence to support the suggestion that a lower number of drops on day 1 is as effective as a higher number on categorized BK ulcers. Conclusions: No standardized method of categorizing BK was found, and there is no evidence to support the contention that mild, moderate, or smaller BK ulcers should be treated any differently to larger or severe ulcers on day 1. The manufacturers of 2FQ do not supply different treatment regimens for different ulcer sizes and severity categories. When using the 2FQ, all BK ulcers should be treated equally in line with the manufacturers' recommended day-1 treatment regimen.

Comparison of Hybrid Contact Lenses and Rigid Gas-Permeable Contact Lenses in Moderate and Advanced Keratoconus.

Objectives: We aimed to compare the clinical results and topographic data of the new generation hybrid contact lens (HCL) and rigid gas-permeable contact lens (RGPCL) in patients with moderate and advanced keratoconus. Materials and Methods: In this prospective study, HCL users comprised group 1 and RGPCL users comprised group 2. Snellen uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and lens-corrected visual acuity (LCVA); manifest spherical-cylindrical values; corneal topography measurements (flat keratometry [K1], vertical keratometry [K2], mean K, maximum K [Kmax], central corneal thickness [CCT], and thinnest corneal thickness [TCT]); and cone location were recorded. Results: The study included 83 eyes of 51 patients in group 1 and 61 eyes of 40 patients in group 2. The groups were similar in age and gender (p>0.05). Mean LCVA (logMAR) was significantly lower than BCVA in both groups (p<0.001). The mean visual gain with contact lenses (Snellen chart) was 3.4±1.8 lines in group 1 and 4.0±2.1 lines in group 2. There was no significant difference between the two groups in BCVA, LCVA, or lines gained (p>0.05). There was also no significant difference between the two groups in terms of keratoconus stages, mean Kmax, CCT, TCT, or cone location (p>0.05), while mean UCVA (logMAR) and mean K were higher in group 2 (p<0.05). In both groups, the visual gain with lenses was higher in eyes with central cones, and there was significantly greater visual increase in group 2 (p=0.039). Conclusion: In moderate and advanced keratoconus, HCLs improved vision as much as RGPCLs and both lenses were more effective for central cones. Nevertheless, longer term of follow-up and larger numbers of patients are needed for long term follow-up results of HCL.

Incidence and Pattern of Neuro-Ophthalmological Disorders Presenting to Vitreoretinal Clinics in Bhutan: A 3-Year National Study.

Purpose: To inform national health policy, we quantified the pattern of neuro-ophthalmological disorders (NODs) presenting to the national vitreoretinal clinics in Bhutan. Study Design: Retrospective cross-sectional study. Methods: We reviewed all new NODs patients over three years. Demographic data, presenting complaints, treatment history, systemic diseases, diagnostic procedures, and diagnoses were quantified. Logistic regression examined the odds of factors linked to more common NODs. Results: Of 226 patients, the majority were males (54.0%), farmers (60.2%), and urbanites (55.8%). Loss of vision was the most common presenting complaint (57.9%), followed by head or orbital trauma (19.5%). The best corrected visual acuity (BCVA) of 216 eyes (47.8%) was ≤6/60. Hypertension was the most common systemic disease (16.4%), followed by diabetes (3.5%), and intracranial space-occupying lesions (3.5%). Neuroimaging (37.6%) was the most common diagnostic test performed, followed by visual field testings (VFTs) (22.9%). With a NOD incidence of 7.8% p.a. (226/2913), optic atrophy (OA) was diagnosed in 134 patients (59.3%). Other common NODs were optic neuritis (15.5%), papilloedema (9.3%), and traumatic optic neuropathy (8.4%). Female gender increased the odds for glaucomatous OA by 2.65× (p = 0.044), and age by 1.09× per year (p < 0.001). Being female increased the odds of optic neuritis by 2.57× (p = 0.03). Conclusion: Over half of the NODs were OA, which could be curable with timely treatment. Improved treatment of glaucoma and non-communicable diseases would reduce the risk of NODs-induced visual loss in Bhutan. The need for improved neuro-ophthalmological assessment and a coordinated multidisciplinary approach to NODs are the highest priorities.

36-Month Outcomes of Mechanical and Transepithelial PTK Epithelium Removal Techniques Prior to Accelerated CXL for Progressive Keratoconus.

PURPOSE: To compare the 36-month visual, refractive, and topographic results and the optical quality of the cornea between mechanical and transepithelial phototherapeutic keratectomy (PTK) epithelium removal techniques prior to the accelerated corneal cross-linking (CXL) procedure in patients with progressive keratoconus. METHODS: Keratoconic eyes that received either mechanical epithelium removal or transepithelial PTK epithelium removal prior to accelerated CXL with 36 months of follow-up were included. The uncorrected (UDVA) and corrected (CDVA) distance visual acuity, spherical equivalent (SE), manifest astigmatism, flat keratometry (K1), steep keratometry (K2), maximum keratometry (Kmax) readings, thinnest corneal thickness (TCT), topographic astigmatism, point spread function (PSF), and aberrometric parameters including root mean square higher order aberrations (RMS HOAs), vertical coma, and spherical aberration (SA) were assessed preoperatively and 12, 24, and 36 months postoperatively. RESULTS: One hundred ten eyes of 110 patients with keratoconus were included (mechanical epithelium removal group: 69 eyes, transepithelial PTK epithelium removal group: 41 eyes). After the CXL procedure, the mean UDVA, CDVA, manifest astigmatism, RMS HOAs, SA, vertical coma, and PSF improved significantly throughout the follow-up visits in both groups (P < .05 for all variables). The improvement in the mean UDVA, CDVA, manifest astigmatism, K1, K2, Kmax, RMS HOAs, SA, vertical coma, and PSF were significantly better in eyes that underwent transepithelial PTK epithelium removal when compared to eyes that underwent mechanical epithelium removal during the follow-up period (P < .05 for all variables). CONCLUSIONS: Transepithelial PTK-assisted accelerated CXL seems to be more efficient in improving the visual acuity and the optical quality while stabilizing the cornea compared to the accelerated CXL with mechanical epithelium removal in patients with progressive keratoconus. [J Refract Surg. 2022;38(3):191-200.].

Investigation of Mitophagy Biomarkers in Corneal Epithelium of Keratoconus Patients.

PURPOSE: The pathological mechanisms of keratoconus (KC) have not been elucidated yet. Mitophagy is an important mechanism that eliminates damaged mitochondria under oxidative stress, and it could be one of the leading pathological causes of KC. This study aimed to find out the role of mitophagy in the keratoconic corneal epithelium. METHODS: The corneal epithelia were collected from the 103 progressive KC patients and the 46 control subjects. The real-time quantitative PCR was performed for PTEN-putative kinase-1 (PINK1), PARKIN, p62, and BNIP3 gene expressions in 31 KC and 9 control subjects. Western blot analyses were performed to investigate the protein expressions of PINK1, PARKIN, LC3B, ATG5, and BECLIN in the remaining 109 corneal epithelium samples from 72 patients and 37 control subjects. RESULTS: mRNA and protein expressions of PINK1 decreased significantly in the corneal epithelium of KC patients compared to the control subjects. No significant change was found in mRNA levels of PARKIN, p62, and BNIP3 in KC patients. The protein expression of PARKIN, LC3B, ATG5, and Beclin did not significantly differ between KC patients and control subjects. Gene expression levels of mitophagy biomarkers were not affected by the KC grade. CONCLUSIONS: PINK1/PARKIN-dependent mitophagy is affected in the keratoconic corneal epithelium. We found significant decreases in both mRNA and protein expressions of PINK1 in the keratoconic corneal epithelium. However, we did not observe any other significant change in mitophagy markers. Mitochondrial stress-related mitophagy pathways could be interrupted by the decreased levels of PINK1 in the keratoconic corneal epithelium, but solely PINK1 dysregulation is not likely to induce KC pathogenesis.

Dynamics of keratoconus progression after a previous successful accelerated crosslinking treatment during and after pregnancy.

PURPOSE: To evaluate the effectiveness of previously applied successful accelerated corneal crosslinking (CXL) treatment in keratoconus stabilization during and after pregnancy. SETTING: Ankara Yildirim Beyazit University, Ataturk Training and Research Hospital, Turkey. DESIGN: Prospective clinical study. METHODS: Patients with stable keratoconus (after having an accelerated CXL procedure) who became pregnant were included. Uncorrected (UDVA) and corrected distance visual acuity (CDVA), manifest astigmatism (MA), keratometry (K)1, K2, Kmax, central corneal thickness (CCT), thinnest corneal thickness (TCT), and anterior (AE) and posterior elevation (PE) were recorded at baseline (before CXL), before pregnancy (the last visit after CXL), during pregnancy (third trimester), and after pregnancy (the last visit after pregnancy). RESULTS: 24 eyes of 19 patients were included. The mean time between CXL and conception was 12.4 ± 5.1 months. The mean postpartum follow-up period was 27.6 ± 13.3 months. The mean UDVA, CDVA, MA, and PE values did not show any statistically significant differences during and after pregnancy compared with the post-CXL values (P > .05). The mean Kmax flattened significantly after the CXL procedure (P = .011); however, it increased during pregnancy (P = .037, after CXL vs pregnancy) and then decreased back to the prepregnancy level after pregnancy (P = .035, pregnancy vs after pregnancy). The mean K1, K2, AE, CCT, and TCT remained stable during pregnancy and significantly decreased after pregnancy (P < .05). CONCLUSIONS: Keratoconus seems to progress during pregnancy in corneas that have previously received successful accelerated CXL treatment. However, this progress was mostly temporary, and generally, regression occurred after delivery.

Evaluation of corneal topography, tear film function and conjunctival impression cytology after long-term scleral contact lens wear in keratoconus patients.

Purpose: To investigate the impact of long-term scleral contact lens (ScCL) wear on corneal curvature, corneal thickness, tear film function, and ocular surface in patients with keratoconus.Methods: Sixteen keratoconus patients wearing ScCLs for 6 months were enrolled in the study. Corneal topography, tear osmolarity test, Schirmer 1 test, tear film break-up time (TBUT) test, and impression cytology analysis were assessed at baseline and follow-up examinations.Results: There were no significant differences in visual acuity, keratometric and pachymetric values after 6 months of ScCL wear compared to baseline (p>0.05 for all). Tear osmolarity, Schirmer 1 test, and TBUT test results showed no significant change during follow-up (p>0.05 for all). Median goblet cell density and grade of squamous metaplasia did not differ significantly at 1-month. However, there was a gradual deterioration in goblet cell density and Nelson grade until the third-month visit compared to baseline (p for goblet cell, p=0.003; p for Nelson grade, p=0.003). These impaired cytological features observed at 3-month visit persisted at 6-month visit (p for goblet cell, p=0.008; p for Nelson grade, p<0.001).Conclusion: Six months of ScCL wear did not induce any changes in corneal curvature and thickness and also did not affect tear function tests in keratoconic eyes. The only significant changes observed were a decrease in goblet cell density and metaplastic changes in conjunctival epithelium in impression cytology analysis. Further investigations may be needed to better understand the cause of impairment in cytological features of ocular surface and its clinical implications.

Xanthine oxidase enzyme activity in keratoconic corneal epithelium.

PURPOSE: To assess the activity of xanthine oxidase (XO) enzyme in keratoconic corneal epithelium and to evaluate its relationship with the keratoconus (KC) severity. METHODS: This prospective and randomized study included 66 eyes of 54 KC patients who received corneal collagen cross-linking treatment and 43 eyes of 32 patients who underwent photorefractive keratectomy due to their refractive error. During surgical procedures, the corneal epithelium was mechanically scraped and gathered to analyze the XO enzyme activity spectrophotometrically. The KC group was subdivided into three groups (stages 1, 2, and 3) according to the Amsler-Krumeich classification. The results were compared between the KC and the control group and in between KC subgroups. RESULTS: No significant differences in age and gender were found between the KC and control groups (p = 0.064 and p = 0.296, respectively). The mean XO activity levels of the KC and control groups were 173.57 ± 87.61 and 223.70 ± 99.52 mIU/mg, respectively (p < 0.001). In KC group, 33 eyes were at stage 1, 19 were at stage 2, and 14 were at stage 3. No significant difference was observed between KC subgroups regarding XO activity levels (p = 0.681). CONCLUSION: In this study, our findings revealed that ultraviolet-related pro-oxidant XO enzyme may have a role in the etiopathogenesis of KC. Further studies are needed to support our result. CLINICAL TRIALS REGISTRATION: When we started this study in 2018, we did not have a "Clinical Trials Registration." However, we have ethics committee approval (date: 21. 02. 2018/No: 22).

Five-Year Long-Term Results of Standard Collagen Cross-Linking Therapy in Patients with Keratoconus

Objectives: We aimed to demonstrate the 5-year visual, topographic, and aberrometry long-term results of standard collagen cross-linking (CCL) treatment in keratoconus patients. Materials and Methods: The files and topographic measurements of patients who underwent standard CCL treatment for progressive keratoconus were retrospectively reviewed. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refraction values, and topographic values were evaluated. Results: Thirty-seven eyes of 27 patients were included in the study. The female to male ratio was 15 (56%)/12 (44%) and the mean age was 22.16±6.4 (12-39) years. The increase in UCVA and BCVA was statistically significant at postoperative 1-5 years (all p values <0.05). The changes in the spherical equivalent after CCL were not statistically significant (p>0.05), but the decrease in the manifest astigmatism values were significant after CCL at 3-5 years (p<0.05). Decrease in K2 (steep keratometry) and K apex values were statistically significant at 1-5 years (p<0.05). There was a significant decrease in the thinnest corneal thickness compared to the preoperative values up to 6 months and 1-4 years (p<0.05), but the change at 5 years was not significant (p=0.08). Post-CCL reductions in high-order aberrations and spherical aberrations were significant at postoperative 5 years and 3-5 years (p<0.05). Conclusion: In long-term follow-up, CCL treatment is seen to arrest keratoconus progression, increase vision, and improve visual quality by reducing higher-order aberrations and spherical aberrations. For these reasons, CCL treatment continues to be the first treatment modality in patients with progressive keratoconus.

Relationship between tear eotaxin-2 and MMP-9 with ocular allergy and corneal topography in keratoconus patients.

PURPOSE: To analyze the relationship between the seasonal allergic conjunctivitis (SAC), eotaxin-2, matrix metalloproteinase-9 (MMP-9), and the topographical findings in the keratoconus patients. METHODS: Thirty-four eyes of patients without SAC (Group 1), 34 eyes of patients with SAC (Group 2), and 20 eyes of control subjects (control group) were enrolled. Tear samples of the subjects were collected by Schirmer method. Corneal topography parameters, tear MMP-9, and tear eotaxin-2 levels were analyzed. RESULTS: The mean tear MMP-9 levels in Groups 1 and 2 were significantly higher than in the control group (p = 0.004). MMP-9 level exhibited a positive correlation with the keratoconus stage and a negative correlation with the thinnest corneal thickness (r = 0.294, p = 0.018, and r = - 0.302, p = 0.006, respectively). The tear eotaxin-2 level was higher in Group 2 than in Group 1 and control group which is not statistically significant (p = 0.17). CONCLUSION: The tear eotaxin-2 did not exhibit any difference in the presence of keratoconus. The tear MMP-9 level was higher in the keratoconic eyes, and it showed a correlation with the stage of the disease and the corneal thickness.

Recovery dynamics of multifocal pupillographic objective perimetry from tropicamide dilation.

PURPOSE: To study the pupillary system by combining mydriasis and multifocal pupillographic objective perimetry (mfPOP). In particular, we explored how the dynamics of recovery differ for concurrently measured direct and consensual sensitivity, response delay, and signal-to-noise ratios (SNRs) for binocular mydriasis. METHODS: We recruited 26 normal participants, all with brown irides. The dichoptic mfPOP stimuli concurrently assessed 44-region/eye and both pupils. Two pre-dilation tests were followed by pairs of repeated tests at 1, 2, 4, 6, 8, 12, 24, and 48 h following dilation of both pupils with 1% tropicamide. Three subjects were retested with only the right pupil dilated. Linear models determined the independent effects of mydriasis upon the per-region and pupil measures over time. RESULTS: Post-dilation, the per-region delays initially decreased by 16.3 ± 6.02 ms (mean ± SE) (p < 0.0001, cf. baseline of 471.1 ± 4.36 ms), then increased to slower than baseline by 17.42 ± 5.57 ms after 4 h (p < 0.002), recovering to baseline at 8 h. By comparison, per-region sensitivities (constriction amplitudes) were still reduced by - 6.20 ± 0.70 µm at 8 h (p < 0.0001, cf. baseline of 21.1 ± 0.55 µm), recovered at 24 h, but rebounded at 48 h (p = 0.005). The SNRs for sensitivities and delays both recovered by 8-12 h. Across all the data, sensitivities reduced by 2.67 ± 0.25 µm/decade of age, and delay increased by 15.4 ± 1.98 ms/decade (both p < 0.00001). Data from 3 of the 26 subjects who repeated the testing for monocular dilation found that consensual response sensitivities were larger than direct for 8 h (p < 0.018). CONCLUSIONS: The per-region sensitivities were affected for longer than SNRs or delays. Strong early SNRs indicated proportionately lower pupil noise for larger pupil diameters. Following mydriasis with tropicamide 1%, the constriction amplitude measurements with mfPOP should be considered only after 48 h, but time-to-peak can be measured after 8-12 h.

Assessment of the visual pathways in patients with neurofibromatosis-1 by 3S-space technique with 3-Tesla MRI

Background/aim/AIM: We aimed to evaluate the size/tortuosity of the optic nerve (ON) and the dilatation of the ON sheath (ONS) in neurofibromatosis type 1 (NF-1) patients with 3T-MRI, and to assess the usefulness of 3D-SPACE in imaging the optic pathway, ON, and ONS in NF-1 patients. Materials and methods: Twenty consecutive NF-1 patients without optic pathway glioma (OPG) (Group 1), 16 consecutive NF-1 patients with OPG (Group 2), and 19 controls were included in this study. The thickness and tortuosity of the ON and the diameter of the ONS were measured on STIR and 3D-SPACE images. Results: The thickness of the ON was similar in all groups on STIR images (P>0.05). The mean ONS diameter was higher in Group 2 with this sequence (P=0.009). Controls had significantly lower grades of ON tortuosity than Groups 1 and 2 (P=0.001), and Group 1 had significantly lower ON tortuosity compared to Group 2 (P=0.001). Severe tortuosity was only detected in Group 2. Conclusion: ON tortuosity and ONS diameter were increased in NF-1 patients in the presence of OPG. High-resolution cranium imaging with the 3D-SPACE technique using 3T-MRI seems to be helpful for detection of the optic pathway morphology and pathologies in NF-1 patients.

Transepithelial Phototherapeutic Keratectomy Followed by Corneal Collagen Crosslinking for the Treatment of Pellucid Marginal Degeneration: Long-term Results.

PURPOSE: To evaluate visual, refractive, topographic, and aberrometric outcomes of transepithelial phototherapeutic keratectomy (PTK) + corneal collagen crosslinking in the treatment of pellucid marginal degeneration. METHODS: This retrospective study includes 20 eyes of 15 patients with pellucid marginal degeneration treated with transepithelial PTK + accelerated corneal collagen crosslinking. Visual acuity, refraction, topographic keratometry, pachymetry, and aberrations were recorded pretreatment and 6, 12, 24, and 36 months after treatment. RESULTS: Stabilization in visual acuity was observed throughout the 36 months of follow-up (P > 0.05). The cylindrical value was significantly lower (P < 0.05) during the follow-up compared with the baseline (4.97 ± 2.00, 3.86 ± 2.01, 3.92 ± 2.27, 2.87 ± 1.70, and 3.28 ± 3.12 D at the baseline and postoperative 6th, 12th, 24th, and 36th month, respectively). Spherical equivalent was significantly lower at the 24th (P = 0.02) and 36th month (P = 0.01) follow-up intervals. A significant decrease (P < 0.05) in average keratometry readings was observed in all follow-up points (47.12 ± 4.66, 46.65 ± 4.38, 46.57 ± 4.57, 46.46 ± 4.81, and 46.27 ± 4.46 D, respectively). The maximum keratometry value remained stable (P > 0.05) in all visits (64.30 ± 10.70, 63.49 ± 10.05, 62.97 ± 9.50, 63.33 ± 10.06, and 62.27 ± 10.36 D, respectively). The Baiocchi Calossi Versaci index was significantly lower (P < 0.05) at all follow-up points compared with the baseline (3.21 ± 1.93, 2.99 ± 1.96, 2.96 ± 1.93, 2.82 ± 1.95, and 2.86 ± 1.99 µm, respectively). Central and minimum corneal thicknesses were significantly lower (P ≤ 0.01) compared with the baseline throughout the follow-up. Higher order aberration, trefoil, coma, and spherical aberration values remained stable during the follow-up compared with the baseline (P > 0.05). CONCLUSIONS: The combination of transepithelial PTK with accelerated corneal collagen crosslinking seems to be an effective treatment in patients with pellucid marginal degeneration in the long-term.

Clinical evaluation of different types of contact lenses in keratoconus management.

PURPOSE: To compare the clinical and topographical findings of the keratoconus patients according to the prescribed contact lens type and to investigate the effects of corneal collagen cross-linking (CXL) and cone location on lens selection. METHODS: The records of 301 eyes of 195 keratoconus patients who were prescribed contact lenses were analyzed retrospectively. The eyes were grouped according to the lens type: Soft toric contact lens (STCL), rigid gas-permeable contact lens (RGPCL), hybrid contact lens (HCL) and mini-scleral contact lens (MSCL). The history of having CXL, ophthalmological examination findings, and the topographical findings were compared between the groups. Brown-Forsythe, Chi-square, and post-hoc tests were used to compare the groups. Mann-Whitney U test was used for subgroup analysis. Comparison of the lens-corrected visual acuity (LCVA) and spectacle-corrected visual acuity (SCVA) levels was made with Wilcoxon signed-ranks test. RESULTS: There was no significant difference between the groups regarding topographical cone location, CXL history, spherical refraction, and LCVA. The difference between spectacle-corrected visual acuity and LCVA was higher in RGPCL and MSCL groups than STCL group (p=0.01). Keratometry of RGPCL and MSCL groups were higher than STCL and HCL groups (p=0.01, p<0.001). In RGPCL group, eyes with central cones had a higher increase in visual acuity with contact lenses compared to eyes with paracentral cones (p=0.043). STCL and MSCL were mostly prescribed in mild and severe keratoconic eyes, respectively. In RGPCL group, the increase in visual acuity with contact lens was higher in eyes treated with CXL (p= <0.01). CONCLUSIONS: While STCL and HCL were mostly prescribed in mild keratoconus, RGPCL and MSCL were selected for moderate or advanced disease. If appropriately chosen, all types of contact lenses could result in a good visual acuity level. CXL history did not affect the prescribed lens type. Having central cone location and CXL history in RGPCL group improved visual acuity more efficiently.

Sterile keratitis after uneventful corneal collagen cross-linking in a patient with Axenfeld-Rieger syndrome.

PURPOSE: To report on a keratoconus (KC) patient with Axenfeld-Rieger syndrome (ARS) who developed sterile keratitis after accelerated corneal collagen cross-linking (CXL). METHODS: An 18-year-old patient with ARS and KC who had previously undergone intrastromal ring segment implantation underwent accelerated CXL (9 mW/cm2 UVA intensity for 10 min). RESULTS: After uneventful surgery, the patient presented with severe photophobia, redness of the eye, and decreased vision 72 h following the procedure. Slit-lamp examination showed anterior multiple superficial stromal infiltrates in the central cornea with an overlying epithelium defect. Due to the lack of pain and absence of any pathogen from corneal samples, a diagnosis of sterile keratitis was considered. A combination of topical antibiotic and corticosteroid regimen was administered. Three months after CXL slit-lamp examination showed a mild stromal scar overlying the central cornea, which did not decrease visual acuity. CONCLUSIONS: The mechanism by which the sterile keratitis occurs following CXL remains unclear. For our case, the reason of post-CXL sterile keratitis could be considered as an immune response due to the staphylococcal antigens. Furthermore, the possible developmental disturbance of corneal stroma in ARS might have contributed to the development of post-CXL sterile keratitis.

Investigation of Heme Oxygenase 2 Enzyme Protein Expression in Keratoconus and Normal Human Corneal Epithelium: An Immunohistochemical Study.

PURPOSE: To compare heme oxygenase 2 (HO-2) enzyme levels detected by immunohistochemical staining methods in the cornea epithelium obtained from keratoconus patients and normal subjects. MATERIALS AND METHODS: The keratoconus group included 69 eyes of 69 patients with keratoconus scheduled for cross-linking surgery. The control group included 52 eyes of 52 patients with refractive error scheduled for photorefractive keratectomy surgery. After a detailed ophthalmologic examination, corneal topographic maps of each patient were generated, and then the patients underwent surgery. The corneal epithelium was collected mechanically during the surgery, fixed with formalin, embedded in paraffin blocks, and sectioned by microtomes. HO-2 antibodies were applied to the samples for immunohistochemical evaluation. The intensity of the staining was identified as negative, weak, moderate or strong. The keratoconus group was classified as early (average keratometry (AvrK) ≤ 47 D), moderate (AvrK 47-55 D) and advanced keratoconus (AvrK ≥ 55 D). Finally, intergroup and intragroup comparison analyses were made statistically. RESULTS: In the keratoconus group, 20 (29%) (14 weak and 6 moderate staining) of the 69 corneal epithelial specimens were identified with HO-2 expression. In the control group, 40 (76.9%) (16 moderate and 24 strong staining) of the 52 corneal epithelial specimens were identified with HO-2 expression. HO-2 expression in the corneal epithelial specimens was significantly less in the keratoconus group than in the control group (p < 0.001). There was no substantial difference among the keratoconus subgroups in terms of staining with the HO-2 antibody (p = 0.797). CONCLUSIONS: The HO-2 enzyme staining using immunohistochemical methods was at lower amounts in the keratoconic corneal epithelial cells as compared with normal corneal epithelial cells. The HO-2 enzyme may play a role in the etiopathogenesis of keratoconus.

Optical Performance of the Cornea One Year Following Keratoconus Treatment with Corneal Collagen Cross-Linking.

PURPOSE: The purpose of the study is to assess changes in optical performance of the cornea in patients with keratoconus following treatment with corneal collagen crosslinking (CXL). MATERIALS AND METHODS: One hundred and eleven eyes of 111 consecutive keratoconus patients with 12-month follow-up after CXL were included. The changes in the visual acuity, manifest refractive errors, and corneal topographic parameters were evaluated. Sirius dual-scanning corneal tomography was used to determine the effectiveness of CXL on each patient's total corneal optical quality; preoperative and 12-month postoperative measurements were analyzed over a 4-mm stimulated pupil and were compared with regards to higher order corneal aberrations (total amount of higher order aberrations [HOAs], vertical coma, horizontal coma, vertical trefoil, oblique trefoil, and spherical aberration), vertical and horizontal modulation transfer function (MTF), and Strehl ratio of point spread function (PSF). RESULTS: At 12 months, there was a significant improvement in mean uncorrected visual acuity (UCVA) (P < 0.001), best corrected visual acuity (BCVA) (P < 0.001), spherical equivalent refraction (P = 0.007), and manifest astigmatic refraction (P < 0.001). The corneal topographic measurements revealed a significant decrease in the mean simulated keratometry-1, simulated keratometry -2, and maximum keratometry compared with the baseline measurements (P < 0.001, for all). In addition, there were significant improvements in mean root mean square error values for corneal total HOA (P < 0.001), vertical coma (P < 0.001), and vertical trefoil (P = 0.008) following CXL. Mean MTF and Strehl ratio did not change after CXL (P > 0.05). The improvement in UCVA significantly correlated with the changes in vertical trefoil (r = -0.191, P = 0.044), and the improvement in BCVA and the changes in manifest astigmatic correction were also significantly correlated (r = -0.247, P = 0.009) 12 months after CXL. CONCLUSIONS: CXL treatment for keratoconus led to an improvement in visual, refractive, topographic, and most corneal HOAs outcomes at the 12-month follow-up. However, these improvements were not enough to increase corneal MTF and the Strehl ratio of PSF.

Chiari 1 malformation with optic disc drusen.

A 32 year old female patient with CM 1 diagnosis was referred for the management of papilledema. Ophthalmologic examination revealed normal visual acuity (20/20 in both eyes), normal optic nerve function tests and normal slit-lamp biomicroscopic findings. Fundoscopy revealed bilateral irregular optic nerve heads with blurred margins. B scan ultrasonography (USG) and Spectral domain optical coherence tomography were performed and bilateral optic nerve heads were diagnosed as ODD. We concluded that the pseudopapilledema must be taken into account before making papilledema diagnosis in patients with CM 1 to protect the patients from redundant interventional procedures.

Mechanical versus transepithelial phototherapeutic keratectomy epithelial removal followed by accelerated corneal crosslinking for pediatric keratoconus: Long-term results.

PURPOSE: To compare the 36-month outcomes of mechanical or transepithelial phototherapeutic keratectomy (PTK) epithelial removal before accelerated corneal crosslinking (CXL) for pediatric keratoconus. SETTING: Atatürk Training and Research Hospital, Ankara, Turkey. DESIGN: Retrospective case series. METHODS: Eyes that had accelerated CXL after mechanical (Group 1) or transepithelial PTK (Group 2) epithelial removal were evaluated preoperatively and 12, 24, and 36 months postoperatively. The uncorrected (UDVA) and corrected distance visual acuities, spherical equivalent (SE), manifest astigmatism, and corneal tomographic and aberrometric parameters were assessed. RESULTS: The study included 40 eyes of 35 consecutive keratoconus patients younger than 18 years with a 36-month follow-up. Group 1 comprised 15 patients, and Group 2 comprised 20 patients. Both groups had a significant improvement in UDVA (P = .001 and P = .02, respectively) and a significant decrease in maximum keratometry (K) and thinnest corneal thickness (all P < .001) 36 months postoperatively. The improvements in maximum K, topographic astigmatism, and spherical aberration were greater in Group 2 than in Group 1 at 12 months (P = .03, P = .01, and P = .04, respectively). After 12 months, the outcomes in the 2 groups were more similar. CONCLUSIONS: The initial visual and topographic outcomes of transepithelial PTK ablation were better than those of mechanical epithelium removal before accelerated CXL in pediatric patients with keratoconus. Over the long-term, the results were similar between the 2 groups.