A 29-year-old male was referred following a flap loss after the creation of a thin, irregular flap with a visual acuity of logMAR 0.1 with -2.0 DS-2.75 DC × 175°. Corneal topography and anterior ...segment optical coherence tomography revealed an irregular corneal curvature and epithelial profile. Phototherapeutic keratectomy (PTK) followed by Topography - Guided Custom Ablation Treatment (TCAT), as a modification of the topographic neutralization technique protocol, was planned to regularize the corneal surface and treat the residual refractive error. Postoperatively, the patient showed a best-corrected visual acuity of logMAR 0 with a refractive error of -1 DC × 90°. Regularization of topography and epithelial thickness was seen along with a reduction in astigmatism and higher order aberrations. We report the use of PTK followed by TCAT as a novel method to treat a case of intraoperative flap loss during laser in situ keratomileusis.
The purpose of this case report is to bring forth a rare clinical scenario where preclinical cataract mimics post-LASIK regression and to describe the role of aberrometry in detecting higher order ...aberrations (HOAs) and early lens changes. A 36-year-old female presented with blurring of vision since 1 year after having undergone an uneventful LASIK surgery 3 years prior. Corneal topography and aberrometry were within normal limits. Although the lens was morphologically normal on slit lamp examination, increased HOAs and lenticular density were detected. Since there were no cataractous changes, the patient was advised regular follow-up. A year later, the patient had developed lenticular changes along with a further increase in aberrations and worsening of scatter on densitometry. Increase in aberrations and lenticular density may serve as a marker for cataract development before clinically detectable lenticular changes. This report shows how preclinical cataract can mimic post-LASIK regression with a change in spherical and cylindrical power of the eye. This could result in patients undergoing re-correction in eyes where the primary pathology is in the lens.
Migraine is a multifactorial disorder that presents with unilateral headache and several sensory symptoms. Photophobia is one of the ophthalmic manifestations that cause significant morbidity. The ...trigeminal pathway that innervates the cornea in the form of afferents has been implicated in photophobia associated with chronic migraine. This study investigates changes in the corneal subbasal nerve plexus (SBNP) in chronic migraine patients with and without photophobia.
Thirty-six patients with migraine and photophobia (group 1), 24 patients with migraine without photophobia (group 2), and 24 age- and sex-matched controls (group 3) were studied. A detailed history analysis and ophthalmic evaluation were performed on all subjects. In vivo confocal microscopy (IVCM) with automated CCMetrics software was used to quantify changes in the SBNP in all 3 groups. Measured parameters were compared using analysis of variance.
Analysis of corneal SBNP features revealed a significant decrease in the corneal nerve fiber length (14.76 ± 3.98 mm/mm), total branch density (43.37 ± 21.63 branch points/mm), nerve branch density (30.19 ± 15.76 number of branches/mm), and fiber area (0.005 ± 0.001 total nerve fiber area/mm) in patients of group 1 compared with group 2 (P < 0.05).
Structural changes in nociceptive corneal axons in the SBNP of patients with migraine with photophobia lend further support to the hypothesis that the trigeminal system plays a critical role in the pathogenesis of ocular symptoms in migraine. Our observations demonstrate that SBNP changes on IVCM may serve as a potential imaging marker for ocular symptoms of chronic migraine, and this warrants further investigation.
Dry eye disease (DED) has evolved into a major public health concern with ocular discomfort and pain being responsible for significant morbidity associated with DED. However, the etiopathological ...factors contributing to ocular pain associated with DED are not well understood. The current IVCM based study investigated the association between corneal dendritic cell density (DCD), corneal subbasal nerve plexus (SBNP) features, and serum vitamin D and symptoms of evaporative dry eye (EDE). The study included age and sex matched 52 EDE patients and 43 heathy controls. A significant increase in the OSDI scores (discomfort subscale) was observed between EDE (median, 20.8) and control (median, 4.2) cohorts ( P < 0.001 ) . Similarly, an increase in DCD was observed between EDE (median, 48.1 cells/mm2) patients and controls (median, 5.6 cells/mm2) ( P < 0.001 ) . A significant decrease in SBNP features (corneal nerve fiber length, fiber density, fiber width, total branch density, nerve branch density, and fiber area) was observed in EDE patients with OSDI score >23 ( P < 0.05 ) . A positive correlation was observed between DCD and OSDI discomfort subscale ( r = 0.348 ; P < 0.0003 ) and SBNP features. An inverse correlation was observed between vitamin D and OSDI scores ( r = - 0.332 ; P = 0.0095 ) and DCD with dendritic processes ( r = - 0.322 ; P = 0.0122 ). The findings implicate DCD, SBNP features, and vitamin D with EDE symptoms.
To evaluate transient corneal tissue healing and biomechanical changes between laser in situ keratomileusis (LASIK) and small incision lenticule extraction (SMILE) eyes.
In each patient, one eye ...underwent LASIK and the other underwent SMILE. Optical coherence tomography (OCT) and dynamic Scheimpflug imaging (Corvis-ST) was used to assess tissue healing and biomechanics, respectively. Analyses of OCT scans yielded corneal speckle distribution (CSD) and Bowman's roughness index (BRI). Waveform analyses of deformation amplitude yielded corneal stiffness. Further, corneal force versus corneal deformation data helped compare the two procedures.
BRI increased and then decreased transiently after both treatments (P < 0.05). However, SMILE eyes had BRI similar to that of their preoperative state compared to LASIK eyes at 6-month follow-up. CSD indicated a marked increase in the number of bright pixels and a decrease in the number of dark pixels after SMILE (1-month follow-up) and LASIK eyes (3-month follow-up), respectively. CSD returned to near preoperative state thereafter, respectively. Corneal stiffness change from preoperative state was similar between LASIK and SMILE eyes. However, deformation at discrete values of corneal force indicated some recovery of biomechanical strength after SMILE, but not in LASIK eyes.
BRI and CSD indicated earlier tissue healing in SMILE eyes than in LASIK. CSD results may indicate delayed cell death in LASIK eyes and increased light scatter due to interface fluid in SMILE eyes. Corneal biomechanical strength remodeled better in SMILE. This may indicate some hydration-related recovery.
To report the case of a 40-year-old patient with persistent bilateral ocular pain and discomfort for 2 years in whom conventional management of dry eye had failed. Detailed ocular examination, ...meibography, and tear film evaluation were suggestive of bilateral meibomian gland dysfunction and evaporative dry eye. Topical medication failed to alleviate the patient's symptoms. To identify the cause of pain, imaging was performed with in vivo confocal microscopy and anterior segment spectral domain optical coherence tomography. Systemic evaluation revealed severe vitamin D deficiency with a value of 5.86 ng/mL.
Case report.
In vivo confocal microscopy showed abnormal subbasal nerve plexus morphology, increased dendritic cell density, and enlarged terminal nerve sprouts. A breach in the Bowman layer was detected in both eyes on spectral domain optical coherence tomography. Conventional management having failed, LipiFlow treatment (TearScience, Morrisville, NC) was performed and topical therapy with cyclosporine 0.05%, steroids, and lubricating eye drops was initiated with incomplete symptomatic relief. However, with parenteral therapy for vitamin D deficiency, there was a dramatic improvement in the patient's symptoms.
Inflammation aggravated by vitamin D deficiency results in an altered epithelial profile, Bowman layer damage, recruitment of dendritic cells, and altered subbasal nerve plexus features in patients with chronic dry eye disease. These can serve as potential imaging markers for studying the underlying mechanisms in patients with dry eye disease with persisting symptoms despite aggressive conventional treatment.
To analyze refractive outcomes of wavefront-optimized (WFO) ablation and topography-guided custom ablation (TCAT) profiles using the Allegretto Wave excimer laser platform (Alcon Laboratories, Inc., ...Fort Worth, TX) in the treatment of myopia.
Sixty eyes of 30 patients who underwent LASIK were included in this prospective interventional study. WFO ablation was performed in one eye (WFO group) and TCAT in the fellow eye (TCAT group). The WaveLight FS200 femtosecond laser (Alcon Laboratories, Inc.) was used to create the flap and Allegretto Wave excimer laser (Alcon Laboratories, Inc.) was used for photoablation. The Pentacam HR (Oculus Optikgeräte GmbH, Wetzlar, Germany) and Allegretto Topolyzer (Alcon Laboratories, Inc.) were used to measure the corneal aberrations. Refractive visual outcomes were also compared.
Accuracy, safety, and efficacy were similar in the two groups. The total root mean square (RMS) and RMS of lower order aberrations were significantly better in eyes that underwent TCAT (P < .05). There was a decrease in individual higher order aberrations in the TCAT group, with a statistically significant difference in the spherical aberrations (P = .02). The corneal asphericity (Q value) was not significantly different between the WFO (0.6 ± 0.1) and TCAT (0.51 ± 0.09) groups. The postoperative total RMS of higher order aberrations was lower in the TCAT group, but this was not statistically significant (P > .05). There was a more positive change in Q value and spherical aberrations in the WFO group, but this was not statistically significant.
TCAT and WFO ablation provided essentially equivalent outcomes after myopic LASIK, with induction of fewer lower order aberrations and higher order aberrations following TCAT ablation. J Refract Surg. 2017;33(1):6-10..
In this study, we elucidated the differential expression of a set of local molecular factors in ectatic cone area of the cornea to uncover a functional cause for focal corneal weakening ...characteristic of the keratoconus (KC) disease.
All human corneal samples were collected after approval of Institutional Ethics Committee and informed consent. Keratoconus patients were classified based on clinical parameters, topographical features, and structural deformity. Epithelial cells were collected from KC patients (n = 66) undergoing corneal cross-linking procedures from cone apex and periphery. Nonectatic refractive surgery patients (n = 23) served as controls. The ratio of epithelial gene expression in cone and periphery of each eye was estimated by quantitative PCR and correlated with clinical data. Similar cone versus periphery analysis was done from the KC stroma and from KC patients with Bowman's layer (BL) breach observed by anterior segment optical coherence tomography (OCT).
Epithelium from the cone apex of KC patients had elevated levels of inflammatory factors TNF-α, IL-6, and matrix metalloproteinase 9 (MMP-9) but reduced Lysyl oxidase (LOX) and Collagen IVA1, which also demonstrated correlation with corneal curvature and deformity parameters. Stromal gene expression from KC patients showed trends similar to epithelium. Epithelium collected from the cone apex of BL breached KC patients showed significantly elevated MMP-9, TNF-α, and IL-6 levels but reduced IL-10, tissue inhibitor of metalloproteinases 1 (TIMP-1), and Collagen IVA1 expression.
This study provides the first evidence that altered corneal epithelial and stromal expression of specific genes at the corneal cone apex drives focal structural weakness in KC.
Keratoconus (KC) is a progressive ectatic corneal disorder. There are multiple topographic devices and their varied indices used for diagnosis, detecting progression, and deciding management. It is ...important to understand the repeatablility, intra- test variabililty, and comparability amongst various topographic devices. The Scheimpflug camera-based devices, such as the Pentacam (Oculus, Wetzlar, Germany), Galilei (Ziemer, Biel, Switzerland), and Sirius (Costruzione Strumenti Oftalmici, Florence, Italy) are known to assist in the detection of early keratoconus and subclinical keratoconus. This article reviews the various Scheimpflug camera-based devices in depth, addressing their different indices, diagnostic accuracy, repeatability, and agreement and identifying the strongest parameter of each device. It will guide the practicing clinician by giving practical tips for decision making in the diagnosis and management of keratoconus.
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