Comparison of corneal flap thickness predictability and architecture between femtosecond laser and sub-Bowman keratomileusis microkeratome in laser in situ keratomileusis.

PURPOSE OF THE STUDY: The purpose of the study is to assess and compare the corneal flap thickness predictability and uniformity between Visumax femtosecond laser and Moria sub-Bowman keratomileusis microkeratome in laser in situ keratomileusis procedure to correct myopic and myopic astigmatism refractive errors. METHODS: One hundred eyes from 100 patients were enrolled in this study. Only one eye (right eye) of each patient was chosen for this study. They were divided into two groups of equal size (50 each). Target flap thickness was 90 µm. Flap thickness was measured by anterior segment optical coherence tomography in 7 specified positions at 3 months postoperative. RESULTS: For femtosecond laser group, the average central flap thickness (CFT) was 91.35 µm ± 4.97. There was no statistically significant difference between the target flap thickness and the resultant flap thickness (p = 0.12). When the central, nasal and temporal thicknesses in the same flap were compared, there was no statistically significant difference among these measurements (p = 0.9). For the microkeratome group, CFT was 102.18 µm ± 5.63. There was statistically significant difference between the target flap thickness and the resultant flap thickness (p = 0.001). The central, nasal and temporal thicknesses were compared and there was a statistically significant difference (p = 0.000). CONCLUSIONS: Our study is among few studies in the literature comparing femtosecond laser flap to SBK microkeratome flap. Femtosecond laser creates more predictable flap thickness and more uniform flap architecture. Trial registration Trial registration number: NCT04684888. Trial Registration date: December 2020. Registered at www. CLINICALTRIALS: gov .

A novel de novo KIF21A mutation in a patient with congenital fibrosis of the extraocular muscles and Möbius syndrome.

PURPOSE: To describe the phenotypic characteristics and clinical course of a sporadic case of congenital fibrosis of the extraocular muscles (CFEOM) and Möbius syndrome with a de novo mutation in the KIF21A gene encoding a kinesin motor protein. METHODS: An individual with the rare combination of CFEOM and Möbius syndrome underwent comprehensive ophthalmologic and neurological evaluations. Magnetic resonance imaging (MRI) including diffusion tensor imaging (DTI) tractigraphy at 3T field strength was used to evaluate orbital, encephalic, and intracranial nerve integrity. The proband and her healthy parents underwent screening for mutations in the KIF21A, PHOX2A, and TUBB3 genes. RESULTS: The patient exhibited congenital, nonprogressive, bilateral external ophthalmoplegia, bilateral ptosis, bilateral facial palsy, and developmental delay. Her inability to blink resulted in severe exposure keratopathy and subsequent corneal perforation requiring a penetrating keratoplasty. MRI revealed an unremarkable configuration of the axial central nervous system and preservation of the intracranial portion of cranial nerves I, II, III, V, VI, VII, and VIII (cranial nerve IV is not normally visualized by MRI). A novel and de novo heterozygous KIF21A mutation (c.1056C>G, p.Asp352Glu) in a highly conserved region of the gene was present in the proband. CONCLUSIONS: The reported KIF21A D352E mutation and associated phenotype further expand the clinical and mutational spectrum of CFEOM and Möbius syndrome.

Comparison of corneal epithelial thickness profile in dry eye patients, keratoconus suspect, and healthy eyes.

PURPOSE: To compare the corneal epithelial thickness profile in patients with dry eyes and keratoconus suspect with normal healthy eyes. METHODS: The study involved 120 eyes with an age range from 19 to 30 years. Forty eyes had normal corneal topography and no dry eyes. Forty eyes had dry eyes but had normal corneal topography. The last 40 eyes were keratoconus suspect and had no symptoms or signs of dry eyes. RESULTS: Central epithelial thickness was not different statistically for all eyes. (p-value: 0.1). The superior epithelial thickness was 53.5 µm ±3.1 in the control group, 53.4 µm ±3.5 in the dry eye group, and 53.6 µm ±2.8 in the keratoconus suspect group. No statistically significant difference was found (p-value = 0.7). The inferior epithelial thickness was 55.7 µm ±3.5 in the control, 57.2 µm ±3.19 in the dry eyes, and 52.2 µm ±3.12 in the KC suspects. There was inferior thickening in the dry eyes and thinning in the KC suspects and this was statistically significant (p-value < 0.01). Minimum epithelial thickness was 52.8 µm ±2.91 in the control and 53.2 µm ±3.51 in the dry eyes and it was located superiorly for both groups. In the KC suspects, the minimum thickness was 52.3 µm ±3.19 and was located inferiorly. CONCLUSION: In our study the epithelium appears to be thicker inferiorly in dry eyes and thinner in KC suspects. Displacement of thinnest location on epithelial map may be a helpful early sign of keratoconus. However, follow-up study is necessary to confirm the thinnest location displacement helped in this diagnosis.

Blunt scissors stromal dissection technique for deep anterior lamellar keratoplasty.

OBJECTIVE: We describe a modified technique for performing lamellar dissection in deep anterior lamellar keratoplasty after failure to achieve a "big bubble" detachment of Descemet's membrane (DM) with deep intrastromal pneumatic injection. METHODS: The technique utilizes blunt lamellar dissection with blunt-tipped corneal mini scissors as an alternative to a crescent blade, which can be difficult for surgeons to master and is associated with a high risk of perforation. RESULTS: Other techniques of blunt dissection, such as the Melles technique, cannot be utilized after failure to achieve a big bubble, as emphysema in the stroma prevents visualization of the spatula. In contrast, our blunt scissors lamellar dissection technique takes advantage of the emphysema and microdetachments of DM created by the pneumatic injection. CONCLUSION: This technique provides deep anterior lamellar keratoplasty surgeons with a simple, alternative method of baring DM or achieving a pre-DM plane with minimal residual stroma, after failure to achieve a big bubble.

Differentiating bilateral superior oblique paresis from sensory extorsion.

PURPOSE: To determine whether patients historically diagnosed with bilateral superior oblique paresis (BSOP) categorized into (1) immediate-onset and (2) gradual-onset torsional diplopia groups are also distinguishable on the basis of patterns of subjective misalignment in various directions of gaze, consistent with the gradual-onset group being caused by sensory extorsion rather than by BSOP. METHODS: The medical records of all patients diagnosed with BSOP, V-pattern esotropia, or V-pattern exotropia between 1978 and 2009 were retrospectively reviewed. Those patients with torsional diplopia were classified into immediate- or gradual-onset diplopia groups. The torsional misalignments measured by Lancaster red-green plots were compared, and the surgical outcomes were evaluated. RESULTS: Of 38 patients identified, 27 had immediate-onset and 11 gradual-onset diplopia. There was a statistically significant difference in the increase in extorsion from up- to downgaze between the immediate- versus gradual-onset group (17.8° versus -1.5°, P < 0.001). Patients in the immediate-onset group fared significantly better with bilateral Harada-Ito procedures than with bilateral inferior oblique-weakening procedures (P = 0.02), whereas patients in the gradual-onset group fared equally well with either procedure (P = 0.72). CONCLUSIONS: Extorsion in upgaze is largely absent in patients with immediate-onset BSOP but is present in both up- and downgaze in patients with gradual-onset sensory extorsion. Lancaster red-green testing aids in distinguishing these two groups. The bilateral Harada-Ito procedure is a better procedure for true BSOP, whereas a bilateral inferior oblique-weakening procedure may be preferred for patients with sensory extorsion.

Fusion can mask the relationships between fundus torsion, oblique muscle overaction/underaction, and A- and V-pattern strabismus.

PURPOSE: To evaluate relationships between fundus torsion, A- or V-pattern strabismus, and oblique muscle over- or underaction, and to explore the influence of stereopsis on these relationships. METHODS: The medical records of patients with A or V patterns and/or abnormal ocular torsion seen at a single institution over nearly 30 years were retrospectively reviewed. Data collected were age, objective fundus torsion (estimated by indirect ophthalmoscopy), horizontal deviations in up- and downgaze, oblique muscle over- or underaction, and stereopsis. RESULTS: A total of 396 patients were included. A patterns were observed in 121 patients (30.6%); V patterns in 90 (22.7%). Of the A-pattern patients, 73.6% had superior oblique muscle overaction, whereas 71.1% of the V-pattern patients had inferior oblique muscle overaction (P < 0.0001, r = 0.71), increasing to 78.6% and 86.3%, respectively, for patients without stereopsis (r = 0.78). Of the patients with fundus intorsion, 78.7% had superior oblique muscle overaction, whereas 74.4% of those with fundus extorsion had inferior oblique muscle overaction (P < 0.0001, r = 0.79), increasing to 83.5% and 82.8%, respectively, for patients without stereopsis (r = 0.82). Fundus intorsion occurred in 76% of the A-pattern patients, whereas fundus extorsion occurred in 71.1% of the V-pattern patients (P < 0.0001, r = 0.73), increasing to 78.6% and 86.3%, respectively, for patients without stereopsis (r = 0.79). CONCLUSIONS: Strong correlations were found between fundus intorsion, superior oblique muscle overaction, and A patterns, and between fundus extorsion, inferior oblique muscle overaction, and V patterns. These correlations increased in patients without stereopsis, suggesting that the presence of binocular fusion can partially interfere with the close correlation of these parameters.

Incidence of esotropia developing in subjects previously diagnosed with pseudoesotropia: a pilot study.

PURPOSE: To assess the rate of development of esotropia following the diagnosis of pseudoesotropia among young children. METHODS: Retrospective records review of children diagnosed during an eye examination with pseudoesotropia prior to age 5 years with a reassessment for strabismus completed after age 5 years. RESULTS: Thirty-one patients met the inclusion criteria. The median age at diagnosis of pseudoesotropia was 1.3 years. Fourteen were boys (45%). Six (19.4%) children were subsequently diagnosed with esotropia (95% confidence interval: 7.5 to 37.5%). CONCLUSION: Even when experienced examiners find no misalignment in young children, a small number will later be found with esotropia. Serial examinations and parent education about this possibility need to be considered.

Features of Urrets-Zavalia syndrome after descemet stripping automated endothelial keratoplasty.

PURPOSE: To report a case series of pupil abnormalities consistent with features of Urrets-Zavalia syndrome (UZS) after Descemet stripping automated endothelial keratoplasty (DSAEK) for corneal edema secondary to corneal endothelial cell dysfunction. METHODS: Retrospective chart analysis of subjects who developed UZS after DSAEK at the University of Texas Southwestern Medical Center. RESULTS: We present a series of 7 eyes with features consistent with UZS, after undergoing DSAEK. Elevated intraocular pressures (IOP) were noted in the early postoperative period in all cases. Five of 7 had graft dislocation in the postoperative period and required rebubbling or repeat DSAEK to obtain a well-apposed graft. Patients were followed for 3 to 14 months and showed improvement in visual acuity and IOP, but fixed dilated pupils persisted. CONCLUSION: A fixed irregular or dilated pupil is a rare complication that can be associated with DSAEK surgery. Patients with an elevated IOP and complicated postoperative course seem to be at greater risk for developing iris ischemia and pupil abnormalities consistent with the diagnosis of UZS.

Adjustable suture technique for enhanced transposition surgery for extraocular muscles.

PURPOSE: To evaluate the results of 2 methods of vertical rectus muscle transposition surgery for sixth (abducens) nerve palsy. METHODS: Retrospective, comparative case series. Historically at our institution, transposed vertical rectus muscles were adjusted toward or attached at the adjacent corners of the lateral rectus muscle ("conventional transposition") before the development of a technique in which adjustable sutures are passed beneath the lateral rectus muscle to attach at its opposite corners ("crossed-adjustable transposition"). Comparative outcomes with these 2 techniques were analyzed in a consecutive series of sixth nerve palsy patients. RESULTS: The change from preoperative to postoperative deviation at distance was 39.3(Δ) ± 22.7(Δ) in 23 conventional transposition cases and 48.5(Δ) ± 27.8(Δ) in 19 crossed-adjustable transposition cases, which demonstrated no statistically significant difference (p = 0.24, t-test). Simultaneous medial rectus weakening was needed less in the crossed-adjustable transposition group (37%) than in the conventional transposition group (83%), and this difference was statistically significant. (p = 0.004, Fisher exact test). CONCLUSIONS: Adjustable vertical rectus muscle transposition surgery for the management of chronic sixth nerve palsy, enhanced by passing the adjustable sutures beneath the lateral rectus muscle, requires simultaneous medial rectus muscle weakening less than half as often for satisfactory results.