Comparison of two different 360-degree intrastromal corneal rings combined with simultaneous accelerated-corneal cross-linking.

PURPOSE: to compare five-year outcomes of two complete intracorneal implants (MyoRing versus annular-shaped intracorneal implant [AICI]) combined with accelerated corneal cross-linking (A-CXL) in progressive KCN. METHODS: In this historical cohort study, preoperative and postoperative visual, refractive, tomographic, biomechanical, and aberrometric parameters of 27 eyes of 27 patients who underwent implantation of two complete rings (13 AICI and 14 MyoRing) combined with A-CXL were recorded. RESULTS: The mean age of patients in "AICI plus A-CXL" and "MyoRing plus A-CXL" groups were 28.1 ± 4.6 and 26.3 ± 3.8 years, respectively. All pre- and postoperative visual and refractive parameters between the two groups were not significantly different (p > 0.05). Comparing pre- and postoperative tomographic measurements showed that anterior corneal surface (ACS) flat-K and corneal thickness at pachymetric apex significantly improved for MyoRing plus A-CXL group after five years (p < 0.05). On the other hand, ACS K-max and mean-K values were significantly improved for AICI plus A-CXL group after five years (p < 0.05). Both groups revealed significant improvements in ACS steep-K and corneal astigmatism (p < 0.05). Five years after surgery, the high order aberration in the AICI group (2.60 ± 0.83) was significantly better than the MyoRing group (1.70 ± 0.43) (p = 0.007). CONCLUSIONS: Both complete intrastromal rings (MyoRing or AICI) combined with A-CXL significantly Improved visual, refractive, and corneal aberrometric, biomechanical, and tomographic parameters and halt the progression of KCN with comparable long-term outcomes.

Corneal layer thickness in keratoconus using optical coherence tomography.

CLINICAL RELEVANCE: Accurate thickness measurement of corneal layers using anterior segment OCT can be used to improve visual outcomes. Understanding its applications is essential for optometric practices to enhance eye care procedures. BACKGROUND: To evaluate the thicknesses of different corneal layers for identifying keratoconus (KCN) and subclinical keratoconus (SKCN) using spectral-domain optical coherence tomography (SD-OCT). METHODS: This prospective study analyzed 60 eyes with KCN, 48 eyes with SKCN, and 53 normal eyes. The central corneal thickness (CCT) and thicknesses of the epithelium, Bowman, stroma, and Descemet-endothelium layers were measured using SD-OCT. One way analysis of variance and the area under the curve (AUC) were used to evaluate the parameters. The Delong method was used to compare AUCs. RESULTS: In KCN, CCT and thicknesses of epithelium, Bowman, stroma, and Descemet-endothelium layers were 495.5 ± 41.7, 52.6 ± 6.4,11.5 ± 1.4, 415.5 ± 38.9, and 12.3 ± 1.7 µm, respectively. These thickness values were respectively 524.5 ± 33.3, 56.8 ± 6.8, 11.5 ± 1.6, 439.8 ± 30.6, and 12.4 ± 1.7 µm in SKCN and 563.8 ± 37.9, 57.7 ± 6.9, 12.2 ± 1.6, 469.5 ± 33.7, and 12.8 ± 2.1µm in normal group. Total cornea and stroma in KCN and SKCN, and epithelium in KCN were significantly thinner compared to the normal group (P < 0.001). The highest AUC values were observed for CCT in KCN (AUC 0.90) and SKCN (AUC 0.782). The diagnostic accuracy was significantly higher for stromal thickness in KCN (sensitivity 81.7%, specificity 73.6%, AUC 0.871) and SKCN (sensitivity 80.0%, specificity 56.6%, AUC 0.751) than other individual corneal layers (Delong, P < 0.001) . CONCLUSION: CCT can accurately distinguish keratoconus from normal eyes. However, central corneal stromal thinning was the most sensitive diagnostic index for early detection of SKCN. Developing standardized stromal maps may be helpful for detecting SKCN.

Seven-year follow-up of a novel 360-degree implant (annular intracorneal inlay) plus accelerated corneal cross-linking: A case study.

AIM: to report late visual, refractive, and tomographic findings of a patient with progressive keratoconus (KCN) over 7-year follow-up examinations after treatment with an advanced intrastromal implant known as annular intracorneal inlay (AICI) combined with accelerated corneal cross-linking (ACXL). METHODS: Slit-lamp photography of anterior segment, corneal tomography maps, and manifest refractions were recorded. RESULTS: A 30-year-old female presented with the complaint of gradual decreased visual acuity in recent years that was remarkable in her left eye (LE). After clinical examinations, she underwent AICI implantation plus ACXL on her LE. Seven years later, notable improvements were observed in some visual, refractive, and tomographic parameters. The most obvious change was ascribed to the uncorrected distance visual acuity (UDVA) that was 1.3logMAR and 0.4logMAR, before and 7 years after the operation, respectively. However, the preoperative corrected distance visual acuity (CDVA) improved slightly from 0.3logMAR to 0.22logMAR after 7 years. The values of anterior K-max, mean-K, flat-K, and steep-K were flattened by 1.80 D, 1.10 D, 1.00 D, and 1.30 D, respectively. Most visual, refractive, and tomographic data improved or remained stable after 7 years and no remarkable ocular complication was observed at the end of the 7th year. CONCLUSION: AICI implantation plus ACXL could be considered as a safe and effective strategy in halting the KCN progression and improving the visual and tomographic properties of the KCN patients. However, future prospective studies with more participants are needed to evaluate the potential effect of AICI implantation on KCN progression.

Best indices of dual Scheimpflug/Placido tomographer for keratoconus detection.

PURPOSE: To evaluate the accuracy of different corneal parameters in detecting keratoconus using a dual Scheimpflug/Placido system (Sirius, CSO, Italy). METHODS: Sixty-eight eyes of 68 keratoconus patients and 77 eyes of 77 normal subjects were prospectively assessed in a diagnostic test study. The mean differences of the corneal parameters were compared using the independent t-test. The accuracy of curvature, elevation, pachymetry, and aberrometry indices, aqueous depth, and corneal volume in 10 mm was evaluated using the area under the curve (AUC), and the DeLong method was used for the comparison of AUCs. Multiple tests in a parallel manner and multiple logistic regression analysis were applied to determine the best predictor indices. RESULTS: All indices except aqueous depth and corneal volume were significantly different between the two groups (P < 0.001). Back keratoconus vertex (KVb) and front Baiocchi-Calossi-Versaci index (BCVf) had the highest sensitivity (for both 98.53%) followed by front symmetry index (SIf) (96.12%) and thinnest point of the cornea (88.24%) in elevation, aberrometry, curvature, and pachymetry parameters, respectively. The highest diagnostic ability was observed in KVb (AUC 0.993) and BCVf index (AUC 0.992) (DeLong > 0.05). Multiple test analysis showed a combination of indices with the highest accuracy that was similar to the performance of each one individually, and keratoconus was diagnosed correctly in 98.5% of the cases (R2 = 93%). CONCLUSION: The parameters extracted from Sirius can differentiate keratoconus from normal corneas with high accuracy without the need for complex computational algorithms. Elevation-based and combined aberrometry indices had the highest diagnostic power.

Modified big bubble technique for deep anterior lamellar keratoplasty in keratoconus.

We describe a modified technique for deep anterior lamellar keratoplasty with three modifications in big bubble pneumodissection technique; including two staged stromal trephination to avoid inadvertent full-thickness trephination, deep bevel-up needle air injection for better visualization and deeper air injection and, vicoseperation by refilling the pre-Descemet space with a viscoelastic after removing the air bubble for safe removal of the deep stromal layers. Patients with advanced keratoconus underwent deep anterior lamellar keratoplasty with pneumodissection by two-staged trephination followed by bevel-up needle deep air injection and viscoseperation. The big bubble was successfully formed in all cases and there was no case with the rupture of the Descemet's membrane (DM) during air injection or baring of DM.

Herpetic endotheliitis and stromal keratitis following inactivated COVID-19 vaccination.

Given the scarcity of data regarding ocular complications following COVID-19 vaccination, the approach toward patients with suggestive symptoms and established clinical practice is lacking. Herein, we report the first case of herpetic endotheliithis and secondary stromal keratitis following inactivated COVID-19 vaccination who experienced a relapse due to poor adherence.

Distribution Pattern of Total Corneal Thickness in Keratoconus versus Normal Eyes Using an Optical Coherence Tomography.

Purpose: To evaluate the total corneal thickness distribution pattern using a high-resolution spectral-domain optical coherence tomography (HR SD-OCT) for distinguishing normal eyes from keratoconus (KCN). Methods: One hundred and forty-four patients were enrolled in three groups (55 normal, 45 mild KCN, and 44 moderate-to-severe KCN eyes) in this prospective diagnostic test study. Total corneal thickness was measured in 8 semi-meridians using HR SD-OCT (Heidelberg Engineering, Heidelberg, Germany) in 5 and 7 mm zones. The central corneal thickness (CCT), corneal focal thinning (minimum thickness [Min], min minus median and maximum [Min-Med, Min-Max]), and asymmetry indices (inferior minus superior [I-S] and supranasal minus infratemporal [SN-IT]) were calculated. One-way analysis of variance and the area under the receiver operating characteristic curve (AUC) were used for the analysis. Results: Thinner CCT, lower Min thickness, more negative Min-Max, Min-Med, and greater I-S and SN-IT were found in KCN eyes compared to the control group (P < 0.001). The inferior and IT semi-meridians were the thinnest locations in KCN cases in the 5 mm central zone (P < 0.001). CCT followed by Min-Med had the highest discriminative ability for differentiating mild KCN (AUC, sensitivity and specificity: 0.822, 87.0%, 60.37% and 0.805, 82.93%, 66.0%, respectively) and moderate-to-severe KCN (0.902, 87.82%, 73.08% and 0.892, 85.37%, and 78.85%, respectively) from normal corneas. Conclusion: The inferior and IT sectors of the cornea with the largest thickness changes in the 5 mm zone are the most common thinning sites in keratoconic corneas, and CCT and Min-Med are the most sensitive indices for the diagnosis of KCN.

Comparison of Artificial Intelligence-Based Machine Learning Classifiers for Early Detection of Keratoconus.

PURPOSE: To compare the agreement between artificial intelligence (AI)-based classifiers and clinical experts in categorizing normal cornea from ectatic conditions. METHODS: Prospective diagnostic test study at Noor Eye Hospital. Two hundred twelve eyes of 212 patients were categorized into three groups of 92 normal, 52 subclinical keratoconus (SKCN), and 68 KCN eyes based on clinical findings by 3 independent expert examiners. All cases were then categorized using four different classifiers: Pentacam Belin/Ambrosio enhanced ectasia total deviation value (BADD) and Topographic Keratoconus Classification (TKC), Sirius Phoenix, and OPD-Scan III Corneal Navigator. The performance of classifiers and their agreement with expert opinion were investigated using the sensitivity, specificity, and Kappa index (κ). RESULTS: For detecting SKCN, Phoenix had the highest agreement with the clinical diagnosis (sensitivity, specificity, and κ of 84.62%, 90.0%, and 0.70, respectively) followed by BADD (55.56%, 86.08%, 0.42), TKC (26.92%, 97.50%, 0.30), and Corneal Navigator (30.77%, 93.75%, 0.29). For KCN diagnosis, the highest agreement with expert opinion was seen for Phoenix (80.02%, 96.60%, 0.79), BADD (95.59%, 85.42%, 0.75), TKC (95.59%, 84.03%, 0.73), and Corneal Navigator (67.65%, 96.45%, 0.68). Analysis of different classifiers showed that Phoenix had the highest accuracy for differentiating KCN (91.24%) and SKCN (88.68%) compared to other classifiers. CONCLUSIONS: Although AI-based classifiers, especially Sirius Phoenix, can be very helpful in detecting early keratoconus, they cannot replace clinical experts' opinions, particularly for decision-making before refractive surgery. Albeit, there may be concerns about the accuracy of clinical experts as well.

Topical Minoxidil Solution-Induced Central Toxic Keratopathy following Photorefractive Keratectomy: A Case Study.

Purpose: To report the clinical findings of unilateral central toxic keratopathy (CTK) associated with inadvertent exposure to topical minoxidil 5% solution 1 day after bilateral photorefractive keratectomy (PRK). Methods: Anterior segment slit-lamp photography, anterior segment optical coherence tomography (AS-OCT), pachymetry map, epithelial map, and manifest refractions were recorded. Results: This is a case of a 27-year-old male who underwent bilateral PRK and presented 5 days after surgery with the complaint of acute decreased visual acuity in the left eye (LE). His LE was reportedly exposed to topical ethanol-based minoxidil 5% on postoperative day 1, which he was using as a posthair transplant treatment. Clinical examination showed hyperopic shift, poor visual acuity, central corneal opacity, epithelial irregularity, central corneal thinning, and flattening on AS-OCT. These findings were consistent with a diagnosis of CTK. The patient was monitored with conservative treatment and demonstrated full recovery after 6 months. Conclusion: It is recommended to warn patients who have undergone refractive surgery concerning the use of ethanol-containing agents, such as minoxidil solution, because of the possible risk of CTK, a complication not formally recognized.

Update on Pain Management After Advanced Surface Ablation.

PURPOSE: To provide an update for postoperative pain control strategies to help ophthalmic surgeons establish a more effective management plan for patients who underwent advanced surface ablation surgeries. METHODS: Google Scholar, Scopus, ScienceDirect, and PubMed were the main resources used to search the medical literature. RESULTS: The postoperative cornea's healing process is accompanied by intense pain as the chief complaint in the first days after the operation. Several strategies were developed to relieve postoperative pain after surface ablation procedures. These strategies included different preoperative, intraoperative, and postoperative methods. Considering the preoperative demographic and emotional factors, underlying dry eye, alternative epithelial removal techniques, bandage contact lenses, and topical or oral therapeutic agents are some examples of postoperative pain treatments after surface ablation procedures. CONCLUSIONS: The current review revealed that despite the development of numerous protocols to relieve postoperative pain following surface ablations, the best approach could be a combination of different strategies. In practice, no validated and standardized strategy is available for total elimination of postoperative pain following advanced surface ablation surgeries. [J Refract Surg. 2021;37(11):782-790.].

Comparison of Postoperative Symptoms of Alcohol-Assisted Versus Mechanical Epithelial Removal in Photorefractive Keratectomy: A Contralateral Double Blind Clinical Trial.

PURPOSE: To compare the short-term complaints of postoperative pain, and other ocular discomfort symptoms in patients who underwent photorefractive keratectomy (PRK) with alcohol-assisted epithelial removal in one eye versus mechanical debridement in the other eye. METHOD: A prospective, interventional, contralateral double blind clinical trial was performed on 164 eyes of 82 candidates of PRK surgery. The patients were divided into two groups. The first group was alcohol-assisted PRK group in which the epithelial removal was performed on their right eye. The second group was mechanical PRK group in which epithelial removal was performed on their left eye. A numerical rating scale was given to the patients to describe the severity of postoperative pain on the first day following PRK. Postoperative discomfort symptoms including the complaints of light sensitivity, tearing, blurring, and foreign body sensation was also provided by the survey form. RESULTS: One day following PRK, the mean pain score of the alcohol-assisted PRK group and the mechanical PRK group was 3.4±3.1 and 4.1±3.3, respectively (P=0.019). The highest scores recorded for alcohol-assisted and mechanical treated groups were burning (5.22) and light sensitivity (5.46), respectively. Sixty-eight (82.9%) of all patients experienced postoperative pain, and in 52 (76.5%) of them, the time of pain onset was less than 2 hrs. CONCLUSION: We found less pain and discomfort using alcohol-assisted technique compared with mechanical epithelial removal that was provided by a detailed pain and ocular discomfort symptoms assessment one day following PRK surgery.

Role of artificial tears with and without hyaluronic acid in controlling ocular discomfort following PRK: a randomized clinical trial.

AIM: To compare outcomes of applying preservative free artificial tears (PFAT) with and without hyaluronic acid (HA) in early postoperative course following photorefractive keratectomy (PRK). METHODS: In this triple-blinded randomized clinical trial, PRK procedure was performed on both eyes of 230 patients. Following PRK, patients were divided into three groups: the HA+ group, 44 patients PFAT containing HA; the HA- group, 71 patients PFAT without HA were administered 5 times per day (every 4h); the third group, 115 patients received no PFAT before lens removal. On the 1st and 4th postoperative day, Visual Analogue Score (VAS) was utilized to evaluate patient's level of pain. Participants were asked to complete a questionnaire about the severity of eye discomfort ranked from 0 to 10 (0=no complaint; 10=most severe complaint experienced). RESULTS: In eyes receiving PFAT with or without HA (Drop group), mean scores for epiphora, foreign body sensation, and blurred vision on the 1st postoperative day were statistically lower (P<0.05). Filamentous keratitis (FK) was detected in 11 (4.7%) eyes, and recurrent corneal erosion (RCE) was observed in 5 (2.1%) eyes. In the control group, FK was noted in 16 (6.9%) eyes while 13 (5.6%) eyes had RCE and 5 (2.1%) eyes had corneal haze. The rate of complications was statistically lower in Drop group (P=0.009). However, the aforementioned scores were not statically different between HA+ and HA- group one and two (P=0.29). CONCLUSION: Following PRK, applying PFAT with and without HA yields faster visual recovery, decreases postoperative ocular discomfort and haze formation; however there is no additive effect for HA.

Quantitative real-time polymerase chain reaction analysis in herpes simplex virus keratitis with and without epithelial involvement.

PURPOSE: To evaluate the quantitative real-time polymerase chain reaction (qRT-PCR) analysis in herpes simplex virus (HSV) keratitis with and without epithelial involvement. METHODS: This cross-sectional study was performed on 70 patients with different HSV types and an active ocular lesion in Farabi Eye Hospital, Tehran, Iran. From these 70 patients, 171 samples were collected, including seventy tear samples and 33 scraping samples from involved eyes; and 68 samples from uninvolved fellow eyes. Samples were frozen at - 70 °C until DNA extraction was performed. Quantity of HSV was measured using qRT-PCR in all three samples. RESULTS: The mean age of HSV patients was 52.19 ± 20.42 years (range, 4-85 years). Forty-one (58.6%) HSV patients had epithelial involvement, and 29 (41.4%) patients did not have epithelial involvement. In PCR-positive cases, the mean number of viruses in affected eyes' tears (8,831,234 ± 4,051,979) was significantly higher than uninvolved eyes' tears (182,603 ± 69,141) (P = 0.02). The mean of PCR in HSV patients with and without epithelial involvement was 10,320,269 ± 5,329,800 and 1,469,419 ± 1,070,396, respectively (P = 0.04). The qRT-PCR of involved tears in both groups (with and without epithelial involvement) was significantly higher than unaffected eyes' tears (P < 0.0001 and P = 0.01, respectively). In cases with and without epithelial involvement, the cutoff points of viral load in involved eyes' tears were 281,000 and 126,000 copies, respectively. CONCLUSION: The results indicated that qRT-PCR is an excellent method for the detection of herpes simplex keratitis.

Evaluation of corneal topographic, tomographic and biomechanical indices for detecting clinical and subclinical keratoconus: a comprehensive three-device study.

AIM: To evaluate the diagnostic ability of topographic and tomographic indices with Pentacam and Sirius as well as biomechanical parameters with Corvis ST for the detection of clinical and subclinical forms of keratoconus (KCN). METHODS: In this prospective diagnostic test study, 70 patients with clinical KCN, 79 patients with abnormal findings in topography and tomography maps with no evidence on clinical examination (subclinical KCN), and 68 normal control subjects were enrolled. The accuracy of topographic, tomographic, and biomechanical parameters was evaluated using the area under the receiver operating characteristic curve (AUC) and cross-validation analysis. The Delong method was used for comparing AUCs. RESULTS: In distinguishing KCN from normal, all parameters showed statistically significant differences between the two groups (P<0.001). Indices with the perfect diagnostic ability (AUC≥0.999) were Sirius KCN vertex of back (KVb), Pentacam random forest index (PRFI), Pentacam index of height decentration (IHD), and Corvis integrated tomographic/biomechanical index (TBI). In distinguishing subclinical KCN from normal, Sirius symmetry index of back (SIb; AUC=0.908), Pentacam inferior-superior difference (IS) value (AUC=0.862), PRFI (AUC=0.847), and Corvis TBI (AUC=0.820) performed best. There were no significant differences between the highest AUCs within keratoconic groups (DeLong, P>0.05). CONCLUSION: In clinical KCN, all topographic, tomographic, and biomechanical indices have acceptable outcomes in terms of sensitivity and specificity. However, in differentiating subclinical forms of KCN from normal corneas, curvature-based parameters (SIb and IS value) followed by integrated indices (PRFI and TBI) are the most powerful tools for early detection of KCN.

Comparison of Visual, Tomographic, and Biomechanical Outcomes of 360 Degrees Intracorneal Ring Implantation With and Without Corneal Crosslinking for Progressive Keratoconus: A 5-Year Follow-up.

PURPOSE: To evaluate the long-term (5 years) results of 360 degrees intracorneal ring (ICR) implantation with and without corneal crosslinking (CXL) in patients with progressive keratoconus (KCN). METHOD: This historical cohort study was performed on 35 eyes with progressive KCN, which was randomly divided into 2 groups. Fourteen patients were implanted only with ICR, and 21 patients with KCN were treated with ICR plus CXL simultaneously. Uncorrected distance visual acuity (UCDVA), corrected distance visual acuity (CDVA), and refractive components were collected from patients' medical records. The biomechanical properties of patients were measured using the Corvis ST (Oculus, Inc, Weltzar, Germany). Corneal topography and aberrometry parameters were also recorded from the Pentacam HR device (Oculus). RESULTS: Both UCVA and CDVA increased in both groups after ICR implantation; however, this improvement was more significant in the ICR plus CXL group (P = 0.002 and P = 0.001, respectively). The mean improvement of CDVA in patients with ICR implantation with and without CXL was 0.56 ± 0.67 and 0.33 ± 0.61, respectively. A comparison of the long-term postoperative Tomographic and Biomechanical Index between 2 groups showed a better result in the ICR plus CXL group (P = 0.012). Topographic findings of the anterior corneal surface (flat-K, steep-K, mean-K, and astigmatism) after surgery were significantly better than before surgery in both groups (P < 0.05). CONCLUSIONS: Although ICR implantation alone might halt the KCN progression with acceptable visual, topographic, and biomechanical outcomes, the combination of ICR and CXL has an adjuvant and synergistic effect, especially in long-term follow-up.

Post-LASIK keratectasia in the context of a thicker than intended flap detected by anterior segment optical coherence tomography.

The corneal flap created in LASIK is responsible for most of its advantages in comparison with surface ablation. However, lamellar dissection of the corneal layers in LASIK can also result in serious complications such as corneal ectasia. A 23-year-old man underwent LASIK for correction of -4.75 -2.00@15 in the right eye and -4.50 -2.00@160 in the left eye with a preoperative thinnest corneal thickness of 518 µm/right eye and 513 µm/left eye in 2009. An intended flap thickness and ablation depth in both eyes were 160 µm and 94 µm, respectively, and subsequently, residual stromal bed thickness was 264 µm/right eye and 259 µm/left eye. Several years after surgery, he was referred for the decreased vision. His corrected-distance visual acuity was 0.50 in both eyes. A scissoring reflex was found in retinoscopy. Orbscan imaging was compatible with keratoconus. Anterior segment optical coherence tomography was performed to measure the LASIK flap. It was much thicker (200 µm) than intended (160 µm), and therefore, the residual stromal bed thickness was much thinner. In summary, keratectasia may develop in cases where thicker than expected flaps result in excessive thinning of the residual stromal bed. The obtained results from this case emphasize and remind the importance of intraoperative measurement of flap thickness and using femtosecond and new criteria for patient selection to avoid post-LASIK keratectasia.

MyoRing Implantation with and without Corneal Collagen Crosslinking for the Management of Keratoconus.

PURPOSE: To evaluate the safety and efficacy of femtosecond laser-assisted MyoRing implantation with concurrent corneal collagen crosslinking (CXL) compared to MyoRing alone for the treatment of progressive keratoconus. METHODS: A total of 60 patients were enrolled in this randomized controlled trial. The patients were randomly allocated into two groups. In the first group, MyoRing was implanted, while in the second, it was inserted in the corneal stroma using the same technique, along with simultaneous CXL. Visual, refractive, topographic, and abberometric outcomes were measured preoperatively and at every postoperative visit. RESULTS: Data of 47 patients were available at the end of the study; 28 in the MyoRing group and 19 in the MyoRing + CXL group. The mean uncorrected distance visual acuity (UDVA) improved from 0.79 ± 0.39 logMAR to 0.52 ± 0.31 logMAR (P < 0.05) in the MyoRing + CXL group and from 0.65 ± 0.38 logMAR to 0.62 ± 0.23 logMAR (P = 0.70) in the MyoRing group. CDVA changed from 0.33 ± 0.19 logMAR to 0.25 ± 0.16 logMAR (P = 0.10) in the MyoRing + CXL group and 0.32 ± 0.22 logMAR to 0.33 ± 0.17 logMAR (P > 0.50) in the MyoRing group. The mean keratometry (Km) decreased from 47.5 ± 2.7 D to 43.8 ± 3.2 D (P < 0.001) in the MyoRing group and 49.3 ± 3.4 D to 45.1 ± 3.0 D (P < 0.001) in the MyoRing + CXL group. Besides, horizontal coma was significantly lower in the MyoRing + CXL group (P = 0.022). CONCLUSION: MyoRing insertion combined with CXL is a safe and effective method for the treatment of keratoconus. The visual and topographic outcomes were comparable to that for MyoRing insertion after 10 months; however, horizontal coma was significantly lower in the MyoRing + CXL group.

Simultaneous photorefractive keratectomy and accelerated collagen cross-linking in high-risk refractive surgery (Tehran protocol): 3-year outcomes.

PURPOSE: To evaluate safety and efficacy of performing simultaneous photorefractive keratectomy (PRK) and collagen cross-linking (CXL) in myopic patients with preoperative risk factors for developing keratectasia. METHODS: Seventeen eyes of 15 patients with at least one of the following risk factors were recruited: central keratometry (Kmax) between 48 and 50, difference between inferior, superior corneal power (I-S value) between 1.4 and 1.9 and corneal thickness between 450 and 480 µm. Upon final stage of standard PRK, 0.02% mitomycin was applied for 30-50 s, and then, accelerated CXL was performed for 5 min. Pre- and postoperative Oculus Pentacam® imaging for keratometry values, measurement of uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were done for all patients. RESULTS: Mean follow-up time was 32.08 ± 7.79 months (range 25-49 months). Mean age of patients was 28.78 ± 3.80 years. Mean postoperative spherical equivalent was + 0.19 ± 0.42 (- 0.5 to + 1.0 [D]). Mean UDVA and CDVA improved from 0.9062 ± 0.485 log MAR and 0.0148 ± 0.043 log MAR to 0.0173 ± 0.040 log MAR and 0.0057 ± 0.023 log MAR, respectively (P = 0.011, P = 0.735). Mild degree of early postoperative stromal haze was seen which did not persist more than 6 months. There was no late stromal haze, corneal ectasia or other major postoperative complication in the follow-up period. CONCLUSION: Combined PRK and accelerated CXL is an efficient and safe procedure for high-risk refractive surgery candidates, with no increased risk of persistent corneal haze.

Anterior Uveitis with Posterior Synechia and Iris Atrophy Following Implantation of a Phakic Intraocular Lens.

PURPOSE: To describe a case with acute postoperative uveitis, posterior synechia and iris atrophy following iris-claw phakic intraocular lens (pIOL) implantation. METHODS: A case report. RESULTS: A 26-year-old man with high myopia had implantation of a -14.0 diopter, foldable, iris-claw Artiflex (model 401) anterior chamber pIOL (Ophtec B.V.) in both eyes. On the third postoperative day, the patient had significant postoperative inflammation in the left eye and received topical steroids and mydriatic eye drops. On the fifth postoperative day, the right eye had a round pupil and centered pIOL, but the left eye had an atrophic iris and dilated pupil with significant posterior synechias over the inferior half of the pupil. Despite intensive topical steroid application, the synechias remained one year after surgery. CONCLUSION: Severe uveitis with posterior synechia can occur after iris-claw pIOL implantation. We hypothesized that excessive iris tissue enclavation in the pIOLs haptics and large iridotomies may be an associated factor.