Ablation of mpeg+ Macrophages Exacerbates mfrp-Related Hyperopia.

Purpose: Proper refractive development of the eye, termed emmetropization, is critical for focused vision and is impacted by both genetic determinants and several visual environment factors. Improper emmetropization caused by genetic variants can lead to congenital hyperopia, which is characterized by small eyes and relatively short ocular axial length. To date, variants in only four genes have been firmly associated with human hyperopia, one of which is MFRP. Zebrafish mfrp mutants also have hyperopia and, similar to reports in mice, exhibit increased macrophage recruitment to the retina. The goal of this research was to examine the effects of macrophage ablation on emmetropization and mfrp-related hyperopia. Methods: We utilized a chemically inducible, cell-specific ablation system to deplete macrophages in both wild-type and mfrp mutant zebrafish. Spectral-domain optical coherence tomography was then used to measure components of the eye and determine relative refractive state. Histology, immunohistochemistry, and transmission electron microscopy were used to further study the eyes. Results: Although macrophage ablation does not cause significant changes to the relative refractive state of wild-type zebrafish, macrophage ablation in mfrp mutants significantly exacerbates their hyperopic phenotype, resulting in a relative refractive error 1.3 times higher than that of non-ablated mfrp siblings. Conclusions: Genetic inactivation of mfrp leads to hyperopia, as well as abnormal accumulation of macrophages in the retina. Ablation of the mpeg1-positive macrophage population exacerbates the hyperopia, suggesting that macrophages may be recruited in an effort help preserve emmetropization and ameliorate hyperopia.

Screening Thresholds for the Corneal Tomography in Hyperopic Pakistani Population.

OBJECTIVE: To evaluate key corneal tomography parameters for screening mixed astigmatism and hyperopic males and females for refractive surgery and to compare the data to a previously studied myopic group in Pakistani population. STUDY DESIGN: Cross-sectional, observational study. PLACE AND DURATION OF STUDY: Armed Forces Institute of Ophthalmology AFIO, National University of Medical Sciences, Rawalpindi, Pakistan, from August 2013 to August 2018. METHODOLOGY: WaveLight Allegro Oculyzer II diagnostic device was used to examine eyes of 106 adult hyperopic patients in order to determine normal values of 20 parameters, which are considered most clinically applicable for refractive surgery screening. Kolmogorov-Smirnov test was used to evaluate normality of data. Results for outliers were displayed as 2.5%, 5%, 95% and 97.5% percentiles. RESULTS: Two hundred and nine eyes were examined; 110 men and 99 women with overall mean age of 31+11.7 years. Normal mean anterior segment values included: flat simulated keratometry (K1) 42.1±1.84 diopters (D), steep K2 43.8 ± 1.93 D, K maximum 44.4 ± 1.93 D, K mean 42.9 ± 1.75 D, astigmatism -1.3 ± 1.75 D, pachymetry at thinnest point 546.9 ± 33.3 um, front elevation at thinnest point 5.2 ± 3.47 um, and at the back was 14.1 ± 6.60 um, Ambrosio relational thickness maximum 472.0 ± 88.73, progression index (PI) maximum 1.2 ± 0.18, and anterior chamber depth (ACD) 2.7 ± 0.35 mm. CONCLUSION: Hyperopic patients had greater front and back elevation and pachymetry but lesser keratometry, anterior chamber depth and chamber volume as compared to myopic patients in Pakistani population. Front and back elevation data in this hyperopic study population was slightly higher than previously published studies. Key Words: Refractive surgery, Corneal tomography, Screening, Hyperope.

Refractive Changes After Corneal Stromal Filler Injection for the Correction of Hyperopia.

PURPOSE: To evaluate a new non-ablative and adjustable procedure for laser ablative refractive corneal surgery in hyperopia using the injection of a biocompatible liquid filler material into a stromal pocket. METHODS: A total of 120 stromal pockets were created using a clinical femtosecond laser system in 96 rabbit corneoscleral discs and 24 whole globes. Pockets were cut at a depth of 120 or 250 µm below the epithelial surface. Hyaluronic acid was injected manually into the pocket. To determine the refractive changes, three-dimensional optical coherence tomography images and a specifically developed picture recognition Matlab (The Mathworks) routine were used. RESULTS: After injection, a steepening of the anterior and flattening of the posterior corneal surface was observed, which led to hyperopic correction. The two main factors determining the amount of correction were the pocket depth and the injected volume. After the pocket was homogeneously filled, an initial refractive increase was observed, followed by a linear relation between the injected volume and the refraction increase. CONCLUSIONS: This possible clinical protocol for controlled refraction correction of hyperopia suggests a potential readjustable clinical application. [J Refract Surg. 2020;36(6):406-414.].

Human allograft refractive lenticular implantation for high hyperopiccorrection.

Hyperopia is a common form of refractive error in the United States. Many refractive errors can be treated with refractive surgery methods such as laser in-situ keratomileusis and photorefractive keratectomy; however, in patients with large degrees of hyperopia (≥+5.0 diopters [D]), these surgical methods are limited because of higher rates of refractive regression. Lenticule Intrastromal Keratoplasty (LIKE) is a surgical procedure that can be used to correct refractive errors in patients with high hyperopia. The authors describe the first intrastromal implantation of an allograft lenticule performed for the primary correction of hyperopia in the United States, and demonstrate that LIKE is potentially an effective procedure for the correction of high hyperopia. Mechanisms for achieving the intended refractive correction and the complications our patient experienced, including epithelial ingrowth and flap necrosis, are discussed.

Assessing Repeatability of Pupillometric Measurements in the Eyes of Refractive Surgery Candidates Using Infrared Pupillometer.

PURPOSE: To assess the repeatability of measuring pupil dynamics using an infrared pupillometer. METHODS: A total of 124 eyes of 124 patients scheduled for corneal laser refractive surgery were separated into myopic and hyperopic groups and further subdivided based on high or low levels of astigmatism. Measurements were taken using dynamic pupillometry (Topolyzer Vario; Alcon Laboratories, Inc., Sinking Spring, PA). Main outcome measures were pupil diameter size, the distance between the pupil center and the keratoscopic axis, and the spatial shift of the pupil center. Repeatability of measurements was assessed from test-retest repeatability (2.77 Sw), coefficient of variation, and intraclass correlation coefficient (ICC). RESULTS: The 2.77 Sw of all measured parameters was lower than 0.36 and 0.44 mm for myopic and hyperopic eyes, respectively. ICCs of the pupil diameter measurements were higher than 0.963 and 0.926 in myopic and hyperopic eyes, respectively. ICCs of the distance between the pupil center and the corneal vertex along the x-axis were higher than 0.934 and 0.994 in myopic and hyperopic eyes, respectively. Along the y-axis, ICCs of this distance were higher than 0.417 in myopic eyes and higher than 0.504 in hyperopic eyes. The pupil center shift measurement ICCs were lower than 0.482 and 0.526 for myopic and hyperopic eyes, respectively. CONCLUSIONS: In all groups, the Topolyzer Vario showed excellent repeatability when measuring pupil dynamic parameters except when measuring pupil center shift and distance between the pupil center and the corneal vertex along the vertical axis. [J Refract Surg. 2017;33(8):552-557.].

Hyperopic shift from posterior migration of hydrophilic acrylic intraocular lens optic.

UNLABELLED: Two cases that developed a delayed hyperopic shift in refraction following implantation of a single-piece hydrophilic intraocular lens (IOL) are described. The haptics of the Akreos Adapt IOL were flexed anteriorly by capsular contraction, leaving a marked gap between the optic and the anterior capsule. A third case that had marked capsule phimosis and similar anterior flexion of the haptics but with a stable refraction is also described. In this case, the anterior and posterior leaves of the capsule fused peripherally and the IOL optic position was normal. The effective power of an IOL depends on the distance between the apex of the cornea and the center of the optic. Capsule contraction without fusion of the peripheral capsule can make the haptics of this IOL design flex anteriorly with posterior movement of the optic and a hyperopic shift in refraction. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Variation in Schlemm's canal diameter and location by ultrasound biomicroscopy.

PURPOSE: To measure variations in diameter and location of Schlemm's canal in vivo by ultrasound biomicroscopy. DESIGN: Prospective, single-institution, consecutive case series. PARTICIPANTS: Ninety-four patients with and without glaucoma. METHODS: Under topical anesthesia, an 80-MHz iUltrasound probe (iScience Interventional, Inc., Menlo Park, CA) placed at the 12-o'clock position was used to measure the canal's diameter and its distance from both the anatomic limbus (corneoscleral junction) and the angle (the base of the canal and the angle of iris insertion). MAIN OUTCOME MEASURES: Diameter and location of the canal were measured relative to gender, age, intraocular pressure, race, diagnosis, previous glaucoma surgery, pachymetry, refraction, lens type, axial length, and keratometry. RESULTS: The average canal diameter was 121 microm (+/-45 microm). The canal diameter in hyperopes was larger than the canal diameter in myopes (180+/-69 microm vs. 122+/-45 microm; P<0.001). The diameter of Schlemm's canal was smaller in patients with previous glaucoma surgery compared with patients without glaucoma surgery (98+/-20 microm vs. 125+/-4 microm; P<0.01). The mean distance between the angle and Schlemm's canal was found to be smaller in hyperopes than in myopes (281 vs. 335 microm; P = 0.03). The location of the canal in black patients compared with white patients was found to be more posterior from the limbus (659+/-92 microm vs. 624+/-73 microm; P = 0.05). Similarly, canal location in patients with corneal thickness of more than 555 microm was found to be more posterior to the limbus (702 vs. 625 microm; P<0.01) compared with those with thinner corneas. CONCLUSIONS: When measured in vivo with ultrasound biomicroscopy, Schlemm's canal diameter was significantly smaller (121 microm) than demonstrated in previous histopathologic studies.

High-frequency ultrasound biomicroscopy of silicone posterior chamber phakic intraocular lens for hyperopia.

PURPOSE: To study the intraocular position and anatomic relationships of the PRL-III phakic refractive lens (PRL), a posterior chamber phakic intraocular lens (PCP IOL), in cases of hyperopia using ultrasound biomicroscopy (UBM). SETTING: Centro Oftalmológico Real Vision, Madrid, Spain, and Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Universidad Complutense, Madrid, Spain. METHODS: Eleven phakic hyperopic eyes of 6 patients who had PRL implantation were examined by UBM 1 month after surgery. The PRL position, PRL-crystalline lens peripheral distance, and central distance between the corneal endothelium and the PRL were measured. RESULTS: Eight eyes had both haptics on the zonule, 2 had 1 haptic in the sulcus and 1 on the zonule, and 1 had 1 haptic in the sulcus and the other in the ciliary body. The mean PCP IOL-crystalline lens peripheral distance in the minor axis was 239.7 microm +/- 179.4 (SD) and the mean PCP IOL-endothelium central distance, 2146.98 +/- 219.6 microm. Contact between the PCP IOL and crystalline lens was observed in 1 eye. CONCLUSIONS: In this study of hyperopic eyes, the PRL was located on the zonule in most cases. However, the location of the haptics in the sulcus and contact between the PCP IOL and the crystalline lens that occurred in some cases suggest further study of possible long-term complications is needed.

Refractive lensectomy and accommodating lens implantation in a case of hyperopia.

We present a 39-year-old woman with high hyperopia who developed an intolerance to contact lenses due to dry-eye syndrome and Grave's disease. Refractive lensectomy with implantation of a custom-made +31.00 diopter (D) accommodating intraocular lens (IOL) (1CU, HumanOptics) was performed in both eyes. This foldable IOL has modified haptics with transmission elements that allow axial movement of the IOL optic and capsular bag secondary to contraction of the ciliary muscle. The calculated pseudophakic accommodation induced by the anterior shift of a +31.00 D IOL is 2.20 D per millimeter of axial displacement. After 6 months, the accommodative range determined by defocusing was 3.00 D. The subjective near point with best distance correction was 32.00 cm. Refractive lensectomy and implantation of an accommodating IOL based on focus shift may be a refractive solution in eyes with high hyperopia and a short axial length.

Ultrasound biomicroscopy of the Artisan phakic intraocular lens in hyperopic eyes.

PURPOSE: To study in situ the intraocular position of the Artisan iris-claw intraocular lens (IOL) (model 203) (Ophtec) in phakic hyperopic eyes using ultrasound biomicroscopy (UBM). METHODS: Echograms of the anterior chamber were taken preoperatively and 24 to 317 days postoperatively in 4 eyes implanted with the Artisan IOL (power +4.0 to +6.0 diopters). The preoperative anterior chamber depth (ACD) and the postoperative distance between the IOL and the corneal endothelium (endothelium-optic distance) and between the IOL and the lens were measured. The echograms were assessed for the effect of the IOL on iris tissue. RESULTS: The preoperative ACD ranged from 3.10 to 3.56 mm and the postoperative endothelium-optic distance, from 2.03 to 2.54 mm. The distance between the lens and the posterior surface of the IOL ranged from 0.35 to 0.79 mm. Several UBM echograms showed indentation of iris tissue by the IOL haptics and optic edge, although no pigmentary dispersion was noted. CONCLUSIONS: Adequate space was maintained between the Artisan hyperopic IOL and the corneal endothelium, angle, and crystalline lens. Haptic indentation of the iris, which could lead to pigment erosion, was observed. Preoperative gonioscopy and maintenance of normal intraocular pressure postoperatively suggest the indentation was secondary to inadequate lens vaulting relative to the high natural arch of the iris in hyperopic eyes. Shortening the haptics or increasing the lens vault might resolve this problem.

Primary polypseudophakia for cataract surgery in hypermetropic eyes: refractive results and long term stability of the implants within the capsular bag.

AIM: To determine the long term visual and refractive results, and stability and complications of primary polypseudophakia using poly(methylmethacrylate) (PMMA) intraocular lenses (IOLs) for cataract surgery in hypermetropic eyes. METHODS: Prospective study of 15 short or hypermetropic eyes undergoing phacoemulsification with primary polypseudophakia with two PMMA IOLs implanted within the capsular bag. RESULTS: The spherical equivalent was reduced from a mean +4.87 (SD 3.00) dioptres (D) to -0.12 (1.40 D), and the deviation from the intended refraction was +0.005 (1.30) D, 23.6 (12.36) months post-implantation. The deviation from intended refraction was not statistically significant (p = 0.989; paired t test). Postoperative best corrected visual acuity (BCVA) was 6/12 or better in all eyes without macular or optic nerve co-morbidity. Interlenticular opacification (ILO) in the form of peripheral Elschnig pearls was seen in four (26.67%) eyes. A new type of ILO in the form of usually pigmented deposits in the central interface developed in five (33.33%) eyes and resulted in the appearance of Newton's rings in three. None of the eyes with ILO had any loss of BCVA or hyperopic shift. Six (40%) eyes were within 1 D from the intended refraction and 14 (93.33%) within 2 D. There was no statistically significant difference in the accuracy of the two intraocular lens calculation formulas used (SRK II and SRK/T). CONCLUSION: Peripheral Elschnig pearl-type ILO can occur as a late complication of primary in the bag implantation of two PMMA IOLs. A new type of ILO is described. Both types of ILO have not to date resulted in deterioration of visual acuity in our cohort. Use of appropriate biometry techniques and IOL calculation formulas may yield more accurate refractive results.