The effects of ambient narrowband long-wavelength light on lens-induced myopia and form-deprivation myopia in tree shrews

Here we examine the effects of ambient red light on lens-induced myopia and diffuser-induced myopia in tree shrews, small diurnal mammals closely related to primates. Starting at 24 days of visual experience (DVE), seventeen tree shrews were reared in red light (624 ± 10 or 634 ± 10 nm, 527-749 human lux) for 12-14 days wearing either a -5D lens (RL-5D, n = 5) or a diffuser (RLFD, n = 5) monocularly, or without visual restriction (RL-Control, n = 7). Refractive errors and ocular dimensions were compared to those obtained from tree shrews raised in broad-spectrum white light (WL-5D, n = 5; WLFD, n = 10; WL Control, n = 7). The RL-5D tree shrews developed less myopia in their lens-treated eyes than WL-5D tree shrews at the end of the experiment (-1.1 ± 0.9D vs. -3.8 ± 0.3D, p = 0.007). The diffuser-treated eyes of the RLFD tree shrews were near-emmetropic (-0.3 ± 0.6D, vs. -5.4 ± 0.7D in the WLFD group). Red light induced hyperopia in control animals (RL-vs. WL-Control, +3.0 ± 0.7 vs. +1.0 ± 0.2D, p = 0.02), the no-lens eyes of the RL-5D animals, and the no-diffuser eyes of the RLFD animals (+2.5 ± 0.5D and +2.3 ± 0.3D, respectively). The refractive alterations were consistent with the alterations in vitreous chamber depth. The lens-induced myopia developed in red light suggests that a non-chromatic cue could signal defocus to a less accurate extent, although it could also be a result of "form-deprivation" caused by defocus blur. As with previous studies in rhesus monkeys, the ability of red light to promote hyperopia appears to correlate with its ability to retard lens-induced myopia and form-deprivation myopia, the latter of which might be related to non-visual ocular mechanisms.

Descemet Membrane Endothelial Keratoplasty-Induced Refractive Shift and Descemet Membrane Endothelial Keratoplasty-Induced Intraocular Lens Calculation Error

PURPOSE

The aim of this study was to determine the mechanisms leading to the refractive shift and intraocular lens calculation error induced by Descemet membrane endothelial keratoplasty (DMEK), using ocular biometry and corneal elevation tomography data.

METHODS

This is a retrospective, monocentric cohort study. Eyes which underwent uncomplicated DMEK surgery with available pre-DMEK and post-DMEK Scheimpflug rotating camera data (Pentacam, Oculus, Wetzlar, Germany) were considered for inclusion with an age-matched control group of healthy corneas. Cataract surgery data were collected for triple-DMEK cases. DMEK-induced refractive shift (DIRS) and intraocular lens calculation error (DICE) were calculated. Pearson r correlation coefficient was calculated between each corneal parameter variation and both DIRS and DICE.

RESULTS

DIRS was calculable for 49 eyes from 43 patients. It was 30.61% neutral, 53.06% hyperopic (36.73% > 1D), and 16.32% myopic (6.12% > 1 D). DICE was calculable for 30 eyes of 26 patients: It was 46.67% neutral, 40.00% hyperopic (10.00% > 1D), and 13.33% myopic (3.33% > 1D). DIRS and DICE were mainly associated with variations in PRC/ARC ratio, anterior average radii of curvature (ARC), posterior average radii of curvature (PRC), and posterior Q.

CONCLUSIONS

Our results suggest that ARC variations, PRC/ARC ratio variations, PRC variations, and posterior Q variations are the most influential parameters for both DIRS and DICE. We suggest that a distinction between those different phenomenons, both currently described as "hyperopic shift" in the literature, should be made by researchers and clinicians.

Chorio-Retinal Folds Associated With Orbital Cavernous Venous Malformations

PURPOSE

To determine the incidence of clinically detectable chorio-retinal folds (CRFs) with orbital cavernous venous malformations (OCVMs) and their recovery.

METHODS

Retrospective case-note and imaging review, with estimation of odds ratios in relation to the position and volume of the mass.

RESULTS

Records for 402 patients were reviewed, 83 (21%) having CRFs. The mean logarithm of minimum angle of resolution acuity was similar with or without CRFs (0.37 and 0.31, respectively; p = 0.46), but induced hyperopia was commoner with CRFs (76% vs. 12%; p < 0.001), exophthalmos greater (4.52 mm vs. 2.97 mm; p < 0.001), eye movement restriction commoner (37% vs. 21%; p = 0.004), and disc swelling more prevalent (42%, vs. 17%; p < 0.001). Orbital cavernous venous malformations with CRFs were almost all intraconal (98%; odds ratio 9.96; p = 0.002), and 93% (77/83) midorbital (odds ratio 6.02; p < 0.001). The median size with CRFs was twice that of those without (3.85 ml vs. 1.92 ml; p < 0.001), and two-thirds OCVMs with folds had volumes >2.5 ml ( p < 0.001). The OCVM was excised in 76 of 83 (92%) of CRF group and 213 of 319 (67%) of those without ( p < 0.001). The postoperative acuity was improved or unchanged in 67 of 76 (88%) eyes with folds, and 184 of 213 (83%) without CRFs ( p = 0.84). The proportion recovering an acuity within 1 Snellen line (or better than) the unaffected side was 80% with CRFs and 77% in their absence ( p = 0.63). Induced hyperopia persisted in 39% of all patients, with the mean being higher with CRFs (2.22D vs. 1.02D; p = 0.017).

CONCLUSIONS

CRFs occur in ~25% of mid-intraconal OCVMs. Despite OCVM excision, 39% of operated patients retain significant residual hyperopia (54% if CRFs present before surgery), and 41% of such CRFs remain clinically detectable after surgery (with variable visual impairment). Earlier surgery might, therefore, be advisable in patients with CRFs and/or induced hyperopia.

Effects of air pollution on myopia: an update on clinical evidence and biological mechanisms

Myopia is one of the most common forms of refractive eye disease and considered as a worldwide pandemic experienced by half of the global population by 2050. During the past several decades, myopia has become a leading cause of visual impairment, whereas several factors are believed to be associated with its occurrence and development. In terms of environmental factors, air pollution has gained more attention in recent years, as exposure to ambient air pollution seems to increase peripheral hyperopia defocus, affect the dopamine pathways, and cause retinal ischemia. In this review, we highlight epidemiological evidence and potential biological mechanisms that may link exposure to air pollutants to myopia. A thorough understanding of these mechanisms is a key for establishing and implementing targeting strategies. Regulatory efforts to control air pollution through effective policies and limit individual exposure to preventable risks are required in reducing this global public health burden.

[Anatomical and morphometric features of anterior eye segment structures in hyperopia and the risk of developing primary angle-closure glaucoma]

PURPOSE

To study features of anatomical and morphometric parameters of the structures of anterior eye segment in young patients with moderate and high hyperopia in order to identify the signs of an increased risk of developing primary angle-closure glaucoma (PACG) and its acute attack.

MATERIAL AND METHODS

The study included 160 eyes (80 patients) with axial length (AL) of less than 23 mm. Patients with moderate or high hyperopia were divided into two groups according to their age ranges (the 1^st - 27 patients (54 eyes) under 40 years old; the 2^nd - 27 patients (54 eyes) of 41-50 years old, the comparison group - 26 patients (52 eyes) of 42-50 years old with the initial stage of PACG. AL of the eyes, anterior chamber (AC) depth in the central zone, lens thickness (LT) in the optical zone were measured using IOL Master 700 («Carl Zeiss Meditec AG», Germany). AC volume and peripheral AC depth were measured using rotating Scheimpflug camera Pentacam («Oculus», Germany).

RESULTS

While the average values of AL in patients of the 1^st and 2^nd groups were comparable, a statistically significant decrease in AC depth and a significant increase in LT were revealed in the 2^nd group. There was a statistically significant increase in LT, a decrease in peripheral AC depth and AC volume in the comparison group relative to the 2^nd group. In the 1^st group: in 2 eyes of one 38-year-old patient the maximum proximity of all 3 indices to the median values of the group of patients with PACG was found; in 4 eyes of two other patients (35 and 38 years old), a combination of small AC volume with increased LT or small AC volume with small AC on the periphery was noted.

CONCLUSION

Significant differences in terms of LT, peripheral AC depth and AC volume were found between age-comparable (41-50 years old) healthy individuals with short eyes and patients with initial PACG. In 11% of the eyes of healthy patients with hyperopia aged 21 to 40 years, there was a combination of two or three of the studied morphometric signs, which may indicate the risk of developing PACG.

Quantitative proteomic analysis of scleras in guinea pig exposed to wavelength defocus

Myopia is the most common optical disorder in the world, and wavelength defocus induced ametropia and myopia have attracted great attention. The objective was to identify and quantify scleral proteins involved in the response to the wavelength defocus. Guinea pigs were randomly divided into 3 groups that received different lighting conditions for 8 weeks: white light, short wavelength light, and long wavelength light. Refraction and axial length were measured, Hematoxylin-Eosin staining and transmission electron microscope were adopted to observe the scleral structure, and scleral proteome was also detected to analyze protein abundance by employing TMT labeling method. After light stimulation, the long- and short -wavelength light induced myopic and hyperopic effect on the guinea pig's eye and induced distinct protein signature, respectively. 186 dyregulated proteins between the short- and long-wavelength group were identified, which were mainly located in extracellular region and involved in metabolic process. We also found that 5 proteins in the guinea pigs scleras in response to wavelength defocus were also human myopic candidate targets, suggesting functional overlap between dyregulated proteins in scleral upon exposure to wavelength defocus and genes causing myopia in humans. SIGNIFICANCE: Wavelength defocus induces refractive errors and leads to myopia or hyperopia. However, sclera proteomics respond to wavelength defocus is lacking, which is crucial to understanding how wavelength defocus influences refractive development and induces myopia. In this proteome analysis, we identified unique protein signatures response to wavelength defocus in sclera of guinea pigs, identified potential mechanisms contributing to myopia formation, and found that several human myopia-related genes may involve in response to wavelength defocus. The results of this study provide a foundation to understand the mechanisms of myopia and wavelength defocus induced ametropia.

Visual disturbances during prolonged space missions

PURPOSE OF REVIEW

During prolonged spaceflight, astronauts often experience ocular changes, due to constant head-ward fluid shifts in space as compared with Earth. This article reviews symptoms, likely causes, and potential solutions, such as lower body negative pressure, to counteract space-associated neuroocular syndrome (SANS).

RECENT FINDINGS

Low gravity conditions and other aspects of spaceflight affect the eye detrimentally, causing SANS which is characterized by optic disc edema, choroidal thickening, cotton wool spots, and a hyperopic shift. SANS is probably caused by altered hemodynamic flows in the head and neck as well as mildly elevated intracranial and intraocular pressures. Carbon dioxide and other chemicals in space-craft may influence SANS as well. SANS may be counteracted by using lower body negative pressure, thigh cuffs, spacecraft engineering, and/or artificial gravity by a centrifuge.

SUMMARY

Prolonged space missions are associated with optic disc edema, choroidal thickening, cotton wool spots, and a hyperopic shift. Possible causes and countermeasures are currently being researched to reduce the risk of SANS. Although many countermeasures to SANS are under investigation lower body negative pressure exhibits great promise in counteracting the headward fluid shifts in space. Understanding and prevention of SANS is critical to future space exploration, especially to long-duration missions to the moon and Mars.

Hyperopic Shift after 4-8 Incision Radial Keratotomy: Eight-Year Follow-Up

PURPOSE

To evaluate the prevalence, amount and possible factors connected with the hyperopic shift after radial keratotomy.

BASIC PROCEDURES

We studied 86 eyes (51 patients) which underwent 4-8 incision radial keratotomy (delayed technique), consecutively performed by the same surgeon between February 1983 and November 1988. The diamond-bladed knife was set at 95% of the smallest paracentral ultrasonic corneal thickness measurement and the clear zone diameter was between 3.0 and 3.5 mm. Preoperative myopia ranged from -2.00 to -7.25 diopters (D). The average follow-up was 97.4 months (range 78 to 122 months).

MAIN FINDINGS

After eight years of follow-up, the cycloplegic spherical equivalent was satisfactory: 66.2% of the eyes showed a refractive error within 0.5 D, 17.4% were myopic by more than 0.5 D and 16.2% were hyperopic by more than 0.5 D. The mean refractive error was 0.02 D (SD +/- 0.75 D). Between six months and eight years after surgery a hyperopic shift of more than 0.5 D was found in 40.6% of the eyes. The mean hyperopic shift was higher (0.78 D) in the eyes which had keratometry less than 36 D six months after surgery. Compared to the eyes with keratometry greater than 36 D (mean hyperopic shift 0.38 D), the difference was statistically significant (p < 0.02).

CONCLUSIONS

These results show that keratometry, measured six months postoperatively, plays a fundamental role in the stability of postsurgical refraction, as the risk of hyperopic shift is higher in eyes with keratometry < 36 D.

Long-wavelength (red) light produces hyperopia in juvenile and adolescent tree shrews

In infant tree shrews, exposure to narrow-band long-wavelength (red) light, that stimulates long-wavelength sensitive cones almost exclusively, slows axial elongation and produces hyperopia. We asked if red light produces hyperopia in juvenile and adolescent animals, ages when plus lenses are ineffective. Animals were raised in fluorescent colony lighting (100-300 lux) until they began 13days of red-light treatment at 11 (n=5, "infant"), 35 (n=5, "juvenile") or 95 (n=5, "adolescent") days of visual experience (DVE). LEDs provided 527-749 lux on the cage floor. To control for the higher red illuminance, a fluorescent control group (n=5) of juvenile (35 DVE) animals was exposed to ∼975 lux. Refractions were measured daily; ocular component dimensions at the start and end of treatment and end of recovery in colony lighting. These groups were compared with normals (n=7). In red light, the refractive state of both juvenile and adolescent animals became significantly (P<0.05) hyperopic: juvenile 3.9±1.0 diopters (D, mean±SEM) vs. normal 0.8±0.1D; adolescent 1.6±0.2D vs. normal 0.4±0.1D. The fluorescent control group refractions (0.6±0.3D) were normal. In red-treated juveniles the vitreous chamber was significantly smaller than normal (P<0.05): juvenile 2.67±0.03mmvs. normal 2.75±0.02mm. The choroid was also significantly thicker: juvenile 77±4μmvs. normal 57±3μm (P<0.05). Although plus lenses do not restrain eye growth in juvenile tree shrews, the red light-induced slowed growth and hyperopia in juvenile and adolescent tree shrews demonstrates that the emmetropization mechanism is still capable of restraining eye growth at these ages.

[Analysis of corneal biomechanical changes after femtosecond laser-assisted laser in situ keratomileusis in children with hyperopic anisometropia]

AIM

to analyze corneal hysteresis (CH) and corneal resistance factor (RF) readings obtained with the Reichert Ocular Response Analyzer (ORA) before and after hyperopic femtolaser-assisted laser in situ keratomileusis (FS-LASIK) in children with anisometropia as well as to establish factors that may cause changes in these parameters.

MATERIAL AND METHODS

CH and RF were evaluated before and 1.5 years after FS-LASIK performed on amblyopic eyes of 28 patients aged 6-14 years. Preoperatively, there was a correlation between CH and RF (r=0.41, p=0.03). No correlation was found between CH and age (r=-0.02, p=0.82) or between CH (r=0.00, p=0.98), RF (r=0.04, p=0.83), and cornea thickness.

RESULTS

The mean preoperative CH was 12.56±1.21 mmHg, RF 12.31±1.57 mmHg. Postoperatively, a statistically significant change occurred to both CH (by 0.97±1.51 mmHg, p=0.002) and RF (by 1.42±1.55 mmHg, p=0.000). No correlation was found between CH before and after surgery (r=0.11, p=0.57) as well as between the ablation depth and changes in CH (r=0,04, p=0.83) and RF (r=0.21, p=0.28). Regression analysis showed that the extent of CH (r2=0.52, p=0.00) and RF (r2=0,48, p=0.00) changes was closely related to their preoperative values.

CONCLUSION

The statistically significant relative change in CH and RF after hyperopic FS-LASIK was 8% and 12%, respectively. CH and RF changes correlated with their preoperative values, but not with the ablation depth or cornea thickness.

Femtosecond-assisted laser in situ keratomileusis for consecutive hyperopia after radial keratotomy

PURPOSE

To evaluate femtosecond-assisted laser in situ keratomileusis (LASIK) for the treatment of hyperopic shift after radial keratotomy (RK).

SETTING

Private practice, Siena, Italy.

DESIGN

Prospective case series.

METHODS

Eyes with a spherical equivalent (SE) of +1.0 diopters (D) to +4.0 D after RK with 6 or 8 incisions had LASIK. The flap (nominal thickness 130 μm) was created with a femtosecond laser (LDV Z2); the refractive ablation was performed with an excimer laser (217P). The flap was dissected in a centrifugal fashion along previous RK cuts.

RESULTS

Eighteen eyes of 10 patients were treated. Preoperatively, the mean defocus equivalent was 3.13 diopters (D) ± 0.71 (SD); the corrected distance visual acuity (CDVA) was 0.09 ± 0.06 logMAR. At 9 months, the mean defocus equivalent was 0.51 ± 0.47 D (P < .05), with 13 eyes (72%) having 0.50 D or less of defocus equivalent and 16 eyes (89%) having 1.0 D or less of defocus equivalent. The mean CDVA was 0.04 ± 0.06 logMAR (P < .05). No lines of logMAR CDVA were lost. The mean uncorrected distance visual acuity was 0.11 ± 0.10 logMAR. The safety index was 1.11; the efficacy index was 0.97. No retreatments were performed. Flap complications were limited to an RK incision opening larger than 2 mm in 3 eyes and 1 case of a small, self-limiting epithelial ingrowth.

CONCLUSION

Laser in situ keratomileusis with a low-energy femtosecond laser was a safe and effective approach to treat post-RK hyperopia, causing no relevant inflammation.

FINANCIAL DISCLOSURE

Neither author has a financial or proprietary interest in any material or method mentioned.

Femtosecond Laser Flap Creation for Laser In Situ Keratomileusis in the Setting of Previous Radial Keratotomy

PURPOSE

The aim of the study was to report the outcomes of laser in situ keratomileusis (LASIK) in subjects with previous radial keratotomy (RK) using a novel femtosecond laser setting on a proprietary femtosecond laser platform.

DESIGN

This was a retrospective, consecutive chart review of patients at a single private practice institution.

METHODS

The medical records of 16 eyes of 8 subjects who underwent femtosecond-assisted LASIK for consecutive hyperopia after RK were retrospectively reviewed. The preoperative characteristics, intraoperative details, and postoperative outcomes were analyzed.

RESULTS

All 16 eyes had successful femtosecond laser flap creation without significant intraoperative or postoperative complications. Uncorrected visual acuity significantly improved postoperatively (P = 0.0142) and remained stable through the final follow-up interval at 9 to 12 months postoperatively. None of the subjects lost any lines of best spectacle-corrected visual acuity in the postoperative period.

CONCLUSIONS

The novel femtosecond laser technique described in this study can provide a safe and effective method for patients undergoing LASIK after previous RK. Future investigations are required to further validate the findings reported in this study.

Variations of vitelliform macular degeneration

In this study, 33 patients with proven vitelliform macular degeneration were examined. 3 of the 33 (9%) had multiple extrafoveal lesions rather than the typical macular changes. In addition, hyperopia of more than 3 dptr was present in 44% of patients and the condition was noted to produce vision of less than 20/50 in one eye in 40% of cases, indicating that vitelliform patients often are not legally blind.

Location and Gaze-Dependent Shift of Inferior Oblique Muscle Position: Anatomic Contributors to Vertical Strabismus Following Lower Lid Blepharoplasty?

PURPOSE

This study investigated, using high-resolution magnetic resonance imaging (MRI), inferior oblique muscle (IO) position relative to the adnexa in normal controls, subjects with and without vertical strabismus following lower lid blepharoplasty, and subjects with other hypertropia.

METHODS

Sagittal plane MRI was obtained in central gaze, infraduction, and supraduction in 19 controls, 11 subjects with and 2 without hypertropia following bilateral lower lid blepharoplasty, and 13 subjects with hypertropia unrelated to blepharoplasty. In the plane passing through the center of the inferior rectus muscle (IR), we analyzed IO position relative to the globe, as well as the distance from IO to the skin or orbital floor.

RESULTS

The IO was located approximately 1 mm more anteriorly and 1.2 mm more inferiorly in hypertropic than hypotropic fellow orbits of the blepharoplasty group and controls (P < 0.05). From central gaze to infraduction, IO shift in subjects with blepharoplasty was redirected inferiorly, rather than posteriorly as in all other groups. However, from central gaze to supraduction, IO motion was similar in all groups. There was scarring between the IO-IR pulley and orbital floor in the hypertropic eye after lower lid blepharoplasty.

CONCLUSIONS

Subjects with strabismus following lower lid blepharoplasty exhibit anterior and inferior IO pulley displacement in central gaze, as well as hindrance to normal posterior shift in infraduction. Proximity of IO to the orbital rim and lower eyelid skin is associated with strabismus following blepharoplasty, possibly because lower lid blepharoplasty may change lid forces on the IO-IR pulley system via scar tissue.

Acute corneal edema with subsequent thinning and hyperopic shift following selective laser trabeculoplasty

We report 4 cases of acute corneal edema with subsequent thinning and hyperopic shift following routine selective laser trabeculoplasty (SLT) for the treatment of primary open-angle glaucoma. Four women from 3 clinical sites developed acute corneal edema and haze within 2 days of uneventful SLT. In the following weeks to months, all treated corneas thinned to below pre-procedure thicknesses with resultant hyperopic shifts of nearly 2.0 diopters (D) to greater than 6.0 D. All eyes were moderately to highly myopic prior to SLT (spherical equivalent from -5.00 to -12.5 D). The corrected distance visual acuity 6 to 11 months after SLT was within 2 Snellen lines of the pre-procedure acuity in all patients; 2 patients required contact lenses. Corneal edema with subsequent corneal thinning and resultant hyperopic shift is an uncommon but possibly underrecognized complication of SLT, the etiology of which remains unknown but may be associated with moderate to high myopia.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

[Progressive hyperopic shift after radial keratotomy: possible causes]

AIM

To describe possible causes of progressive hyperopia in patients who underwent radial keratotomy.

MATERIAL AND METHODS

The study enrolled 33 subjects who underwent radial keratotomy earlier in their lives, of them 15 controls (29 eyes, group 1) with no refractive error and 18 patients (35 eyes, group II) with progressive hyperopia. The number and type of keratotomy scars was determined during biomicroscopy. Biomechanical properties of the cornea were assessed by means of bidirectional applanation (Ocular Response Analyzer). Dynamic contour tonometry (Pascal) was also used for intraocular pressure (IOP) measurement. Evaluation of the optic nerve head and retina included standard automated perimetry (Humphrey Field Analyzer) and confocal scanning laser ophthalmoscopy with Heidelberg Retinal Tomograph (HRT III).

RESULTS

Group II showed reliable signs of low corneal rigidity, namely reduction of CH and CRF values (by 2.4 and 1.6 mmHg respectively) and central corneal thickness (by 56 microns) as compared to the controls. Tonometry results differed inconsiderably showing a tendency toward hypertension in both groups. The interquartile range of IOP was 17.8 ÷ 22.4 mmHg in group II and 16.3 ÷ 20.6 mmHg in group I. Changes in retinal light sensitivity and optic nerve head parameters were more pronounced in the controls.

CONCLUSION

Several reasons for lowering of corneal rigidity can be suggested: initial biomechanical parameters of the cornea, surgical interference, and age-related changes. We think that hyperopic shift results from the combination of low corneal rigidity and increased IOP, i.e. not the lamina cribrosa but the cornea becomes the target of ocular hypertension. Thus, patients with weakened corneal refraction after radial keratotomy are at risk for developing glaucoma in the late postoperative period.

Axial eye growth and refractive error development can be modified by exposing the peripheral retina to relative myopic or hyperopic defocus

PURPOSE

Bifocal contact lenses were used to impose hyperopic and myopic defocus on the peripheral retina of marmosets. Eye growth and refractive state were compared with untreated animals and those treated with single-vision or multizone contact lenses from earlier studies.

METHODS

Thirty juvenile marmosets wore one of three experimental annular bifocal contact lens designs on their right eyes and a plano contact lens on the left eye as a control for 10 weeks from 70 days of age (10 marmosets/group). The experimental designs had plano center zones (1.5 or 3 mm) and +5 diopters [D] or -5 D in the periphery (referred to as +5 D/1.5 mm, +5 D/3 mm and -5 D/3 mm). We measured the central and peripheral mean spherical refractive error (MSE), vitreous chamber depth (VC), pupil diameter (PD), calculated eye growth, and myopia progression rates prior to and during treatment. The results were compared with age-matched untreated (N=25), single-vision positive (N=19), negative (N=16), and +5/-5 D multizone lens-reared marmosets (N=10).

RESULTS

At the end of treatment, animals in the -5 D/3 mm group had larger (P<0.01) and more myopic eyes (P<0.05) than animals in the +5 D/1.5 mm group. There was a dose-dependent relationship between the peripheral treatment zone area and the treatment-induced changes in eye growth and refractive state. Pretreatment ocular growth rates and baseline peripheral refraction accounted for 40% of the induced refraction and axial growth rate changes.

CONCLUSIONS

Eye growth and refractive state can be manipulated by altering peripheral retinal defocus. Imposing peripheral hyperopic defocus produces axial myopia, whereas peripheral myopic defocus produces axial hyperopia. The effects are smaller than using single-vision contact lenses that impose full-field defocus, but support the use of bifocal or multifocal contact lenses as an effective treatment for myopia control.

Non-topography-guided photorefractive keratectomy for the correction of residual mild refractive errors after ICRS implantation and CXL in keratoconus

PURPOSE

To evaluate the safety and clinical outcomes of non-topography-guided photorefractive keratectomy (PRK) for the treatment of residual mild refractive errors 6 months after sequential intracorneal ring segment (ICRS) implantation and corneal collagen cross-linking (CXL) in stable keratoconus.

METHODS

This retrospective study included 17 eyes of 14 patients with mild to moderate keratoconus. The ICRS implantation and CXL were performed sequentially with a 4-week interval and non-topography-guided PRK was performed at least 6 months after CXL. Data were collected preoperatively and at the 6-month follow-up visits.

RESULTS

ICRS implantation and CXL induced a significant decrease in keratometry and refraction and an increase in visual acuity. At the 6-month follow-up after ICRS implantation and CXL, uncorrected and corrected distance visual acuity (UDVA and CDVA) significantly improved from 1.17 ± 0.38 and 0.44 ± 0.09 logMAR preoperatively to 0.45 ± 0.11 and 0.17 ± 0.08 logMAR (P = .001) postoperatively, respectively. The mean spherical error decreased from -5.45 ± 1.64 to -2.57 ± 1.15 D (P = .01) and the mean cylinder from 3.86 ± 1.15 to 2.13 ± 1.11 D (P = .01). At the 6-month follow-up after PRK, UDVA significantly improved to 0.18 ± 0.06 logMAR and CDVA was 0.15 ± 0.05 logMAR. The mean spherical error and mean cylinder significantly decreased to -1.10 ± 0.41 D (P = .02) and 0.98 ± 0.37 D (P = .046), respectively. No intraoperative or postoperative complications occurred.

CONCLUSIONS

At the 6-month follow-up, non-topography-guided PRK after ICRS implantation and CXL was found to be an effective and safe option for correcting residual refractive error and improving visual acuity in patients with moderate keratoconus.

Novel membrane frizzled-related protein gene mutation as cause of posterior microphthalmia resulting in high hyperopia with macular folds

PURPOSE

We present a genetic and clinical analysis of two sisters, 3 and 4 years of age, with nanophthalmos and macular folds.

METHODS

Ophthalmological examination, general paediatric examination and molecular genetic analysis of the MFRP gene were performed in both affected siblings.

RESULTS

Clinical analysis showed high hyperopia (+11 D and +12 D), short axial lengths (15 mm) and the presence of macular folds and optic nerve head drusen. Autofluorescence of the retina was generally normal with subtle macular abnormalities. Sequence analysis showed compound heterozygosity for severe MFRP mutations in both sisters: a previously reported p.Asn167fs (c.498dupC) and a novel stop codon mutation p.Gln91X (c.271C>T).

CONCLUSION

These are the youngest nanophthalmos patients in the literature identified with severe loss of MFRP function, showing already the known structural abnormalities for this disease. Adult patients affected by homozygous or compound heterozygous MFRP mutations generally show signs of retinal dystrophy, with ERG disturbances and RPE abnormalities on autofluorescence imaging. ERG examination could not be performed in these children, but extensive RPE abnormalities were not seen at this young age.

[Choroidal melanoma - evolution and prognosis]

Choroidal melanoma is the most common primary intraocular malignant tumor. We present the case of a 62 year old patient who was diagnosed with intraocular tumor in his right eye, for about three years. Regarding the fact that the patient refused any kind of treatment during this period, we just had the opportunity to monitor this case. Finally, the diagnosis was choroidal melanoma, confirmed by the histopathological exam.

[Regularities of structural and functional visual system changes in patients with myopic refraction and presbyopia]

Two age groups of 57 patients with noncomplicated low or moderate myopia were examined to reveal the regularities of structural and functional visual system changes in patients with myopic refraction and presbyopia. Characteristics of visual impression, anatomic and physiologic parameters were studied. Presbyopia development in patients with myopic refraction was found to occur on the background of significant changes in anatomic proportions and optic parameters of the eye, decrease of functional capability of visual system and development of abnormal functional system of visual perception. The key mechanisms of presbyopia development in myopia besides the accommodation decrease are pupil dysfunction and binocular interactions disintegration i. e. all the near vision reflex components.

[How can the shift of refraction due to vitreous substitutes be avoided? Posterior chamber intraocular lens for patients suffering from diabetic retinopathy]

Silicone filling of pseudophakic eyes usually results in strong unilateral hyperopia and binocularity is severely disturbed. This problem can be avoided by designing a concave posterior lens surface with the centre of curvature in the macula (Acri.Lyc 59RET®, haptics in capsular bag, body in vitreous cavity). The prospective study on 40 eyes with idiopathic macular foramen yields a mean refraction difference of 0.22 D with and without oil. The A-constant of the lens was found to be 115.7. Clinically relevant aniseikonia did not occur. The main indication is cataracts combined with diabetic retinopathy.

Refractive lens exchange with intraocular lens implantation in hyperopic eyes of a patient with Angelman syndrome

We describe a patient with Angelman syndrome with severe developmental delay who was visually impaired by uncorrected high hyperopia and poor control of accommodation. Refractive lens exchange with intraocular lens implantation was performed in both eyes when the patient was 22 years of age. Satisfactory anatomical and functional outcomes were achieved and maintained during 3 years of follow-up. Refractive lens exchange can be useful in patients with severe neurobehavioral disorders in the presence of high refractive error and poor accommodative control.

FINANCIAL DISCLOSURE

Neither author has a financial or proprietary interest in any material or method mentioned.

Hemiretinal form deprivation: evidence for local control of eye growth and refractive development in infant monkeys

PURPOSE

To determine whether refractive development in primates is mediated by local retinal mechanisms, the authors examined the effects of hemiretinal form deprivation on ocular growth and the pattern of peripheral refractions in rhesus monkeys.

METHODS

Beginning at approximately 3 weeks of age, nine infant monkeys were reared wearing monocular diffuser lenses that eliminated form vision in the nasal field (nasal field diffuser [NFD]). Control data were obtained from the nontreated fellow eyes, 24 normal monkeys, and 19 monkeys treated with full-field diffusers. Refractive development was assessed by retinoscopy performed along the pupillary axis and at eccentricities of 15 degrees, 30 degrees, and 45 degrees. Central axial dimensions and eye shape were assessed by A-scan ultrasonography and magnetic resonance imaging, respectively.

RESULTS

Hemiretinal form deprivation altered refractive development in a regionally selective manner, typically producing myopia in the treated hemifields. In particular, six of the NFD monkeys exhibited substantial amounts (-1.81 to -9.00 D) of relative myopia in the nasal field that were most obvious at the 15 degrees and 30 degrees nasal field eccentricities. The other three NFD monkeys exhibited small amounts of relative hyperopia in the treated field. The alterations in peripheral refraction were associated with local, region-specific alterations in vitreous chamber depth in the treated hemiretina.

CONCLUSIONS

The effects of form deprivation on refractive development and eye growth in primates are mediated by mechanisms, presumably retinal, that integrate visual signals in a spatially restricted manner and exert their influence locally.

Effects of form deprivation on peripheral refractions and ocular shape in infant rhesus monkeys (Macaca mulatta)

PURPOSE

To determine whether visual experience can alter ocular shape and peripheral refractive error pattern, the authors investigated the effects of form deprivation on refractive development in infant rhesus monkeys.

METHODS

Monocular form deprivation was imposed in 10 rhesus monkeys by securing diffuser lenses in front of their treated eyes between 22 +/- 2 and 163 +/- 17 days of age. Each eye's refractive status was measured longitudinally by retinoscopy along the pupillary axis and at 15 degrees intervals along the horizontal meridian to eccentricities of 45 degrees . Control data for peripheral refraction were obtained from the nontreated fellow eyes and six untreated monkeys. Near the end of the diffuser-rearing period, the shape of the posterior globe was assessed by magnetic resonance imaging. Central axial dimensions were also determined by A-scan ultrasonography.

RESULTS

Form deprivation produced interocular differences in central refractive errors that varied between +2.69 and -10.31 D (treated eye-fellow eye). All seven diffuser-reared monkeys that developed at least 2.00 D of relative central axial myopia also showed relative hyperopia in the periphery that increased in magnitude with eccentricity. Alterations in peripheral refraction were highly correlated with eccentricity-dependent changes in vitreous chamber depth and the shape of the posterior globe.

CONCLUSIONS

Like humans with myopia, monkeys with form-deprivation myopia exhibit relative peripheral hyperopia and eyes that are less oblate and more prolate. Thus, in addition to producing central refractive errors, abnormal visual experience can alter the shape of the posterior globe and the pattern of peripheral refractive errors in infant primates.

Measuring the refractive properties of the diabetic eye during blurred vision and hyperglycaemia using aberrometry and Scheimpflug imaging

PURPOSE

This study aimed to measure the refraction and geometry in the diabetic eye during the presence and absence of hyperglycaemia and blurred vision, using aberrometry and Scheimpflug imaging.

METHODS

Aberrometry and Scheimpflug imaging were used to examine ocular refraction and higher-order aberrations, as well as the shape of the cornea and the lens, in 25 patients with diabetes mellitus. From these parameters, the equivalent refractive index of the lens was calculated. Using paired t-tests, comparisons were made between a first series of measurements (Visit 1) taken in the presence of blurred vision and hyperglycaemia (> 10.0 micromol/l), and a second series of measurements (Visit 2) taken under normal conditions.

RESULTS

The mean difference in blood glucose between Visits 1 and 2 was 5.9 mmol/l (standard deviation [SD] 3.1) (p < 0.0001). Both small hyperopic and myopic shifts of equivalent refractive error (ERE) were found in nine patients (mean absolute difference ERE: 0.38 D [SD 0.12]; p = 0.02). Furthermore, higher-order aberrations (root mean square [RMS] error) were slightly increased in four patients (mean difference RMS error: 0.07 microm [SD 0.02]; p = 0.04) at Visit 1, compared to Visit 2. No significant changes were observed in the shape of the cornea or lens in any of the patients. No significant correlations were found between changes in blood glucose levels and the measured parameters in diabetic eyes.

CONCLUSIONS

The present study suggests that subjective symptoms of blurred vision during hyperglycaemia are not necessarily caused by changes in the refractive properties of the diabetic eye.

Correction of residual hyperopia after cataract surgery using the light adjustable intraocular lens technology

PURPOSE

To determine whether residual hyperopia could be corrected postoperatively using the light adjustable lens technology in patients undergoing cataract surgery and light adjustable lens implantation.

DESIGN

Prospective, nonrandomized clinical trial.

METHODS

Fourteen eyes of 14 patients were studied. The manifest refraction, uncorrected visual acuity (UCVA), and best-corrected visual acuity (BCVA) were determined with follow-up time to determine the achieved refractive corrections and their stability.

RESULTS

Of 14 eyes, 13 eyes (92.9%) achieved +/- 0.25 diopters (D) of the target refraction at one day post lock-in, with 100% of the eyes achieving the targeted refractive adjustment within 0.5 D or better up to six months postoperative follow-up. All eyes treated show no change in manifest spherical refraction >0.25 D between one day post lock-in, and three and six months postoperative visits. The data demonstrate the stability of the achieved refractive change after the adjustment and lock-in procedures. The mean rate of change was 0.006 D per month, which is six times more stable than that of refractive procedures.

CONCLUSIONS

Residual hyperopia errors in the range of +0.25 to +2.0 D were successfully corrected with precision and significant improvement in UCVA and without compromising BCVA using the light adjustable intraocular lens technology.

The convex retina: optical coherence tomography in hypermetropic shift, without choroidal folds, from intraconal cavernous haemangioma

A 36-year-old female referred with improving unaided vision in her left myopic eye was found to have a left 4.5 diopter hypermetropic shift. Examination revealed a left 2 mm proptosis but was otherwise normal with no choroidal folds on fundoscopy and bilateral 6/5 corrected vision. Her visual field and B scan image were also unremarkable. Optical Coherence Tomography (OCT) imaging demonstrated left-sided anterior retinal bowing with a convex retinal appearance. Magnetic Resonance Imaging (MRI) confirmed a well-circumscribed intraconal mass. The intraconal mass was successfully removed via lateral orbitotomy and confirmed as a cavernous haemangioma on histological assessment. We document these OCT findings and review published ultrasound detected scleral deformation from similar retro-orbital mass cases.

[Ophthalmological findings in pediatric brain neoplasms: 58 cases]

PURPOSES

To describe the visual manifestations of brain neoplasms, and to analyze the effect of tumor control on these.

METHODS

This is a descriptive retrospective study, which includes patients under 14 years of age, suffering from different brain neoplasms in our hospital between 1996 and 2005 inclusive.

RESULTS

In the group of patients with low visual acuity, 44% had organic amblyopias. In 28% of cases, the amblyopia was secondary to the strabismus/nystagmus produced by the developing tumor. Corrective treatment was successful in some cases of partial or total organic amblyopia. Ophthalmologic evaluation (including perimetry and fundoscopy) enabled detection of 3 tumor relapses.

CONCLUSIONS

Visual analysis (visual acuity, perimetry, fundoscopy) should be an essential component of assessment during brain neoplasm treatment and follow-up. Corrective treatment is sometimes successful in organic amblyopias

Femtosecond laser for residual refractive error correction after refractive lens exchange with multifocal intraocular lens implantation

PURPOSE

To assess visual and refractive outcomes of femtosecond laser for residual refractive error correction after refractive lens exchange (RLE) with multifocal intraocular lens (IOL) implantation.

DESIGN

Prospective, nonrandomized, masked observational case series (self-controlled).

METHODS

Fifty-three eyes of 31 consecutive patients were submitted to femtosecond laser surgery after RLE with multifocal IOL implantation. Patients showed an average manifest refractive error (D) of M, 0.200 +/- 0.490; J(0), -0.051 +/- 0.532; and J45, -0.007 +/- 0.371. Visual acuity (VA) was measured at distance and near vision before and six months after the surgery.

RESULTS

At six months after surgery, mean uncorrected VA was 0.83 +/- 0.20 and improved in 100% of the eyes. No eye lost two or more lines of best-corrected distance VA; five eyes lost one line, 31 eyes did not change after the surgery, 13 eyes gained one line, and four eyes gained two lines. All eyes were within +/- 1.00 diopters (D) and 96.2% were within +/- 0.50 D of the desired refraction. The average manifest refractive error (D) after surgery was M, 0.014 +/- 0.170; J0, 0.029 +/- 0.118; and J45, 0.007 +/- 0.061. No eye lost two or more line of best distance-corrected near VA; two eyes lost one line, 40 eyes did not change, and 11 eyes gained one line. Mean uncorrected distance near VA was 0.88 +/- 0.12 at six months. Best distance-corrected near VA changed from 0.89 +/- 0.14 before surgery to 0.90 +/- 0.13 at six months.

CONCLUSIONS

Femtosecond laser after RLE with multifocal IOL implantation is an effective procedure for correcting residual ametropia and resulted in better distance visual outcomes.

[Refractive state in patients with phacoemulsification of cataract in uncommon situations]

BACKGROUND

We undertook this study to determine the refractive state in patients who underwent non-complicated phacoemulsification under unusual situations.

METHODS

This was a clinical, open, transversal, prospective and comparative study. Patients had the following conditions: congenital cataracts, hyperopia, myopia, and emetropia with previous corneal transplantation or vitreous cavity filled with silicone oil.

RESULTS

Thirty-six eyes were included in our study vs. control group (52 emetropic eyes). There was no statistical significance in spherical equivalent 6 weeks postoperatively, with 59% of patients within +1.00 D, 73% +2.00 D and 28% > +2.00 D.

CONCLUSIONS

Refractive state was favorable with an average of 0.96 D +/- 6.27.

Two siblings with small eyes

Posterior microphthalmos is a rare congenital bilateral eye disorder, of which the posterior segment is abnormally small. Additional features include high hypermetropia and a tendency to uveal effusion. We report two siblings who present with high hypermetropia and other features of posterior microphthalmos. Fundus examination revealed the typical crowding of the optic disc and retinal folds. We discuss clinical characteristics, pathogenesis and complications of this disorder.

[Infant ametropias and their evolutions (myopia, hyperopia, astigmatism)]

Infant ametropias are defined as the whole optic caracteristics of the eyeball which do not allow a clear vision whithout functional disorder. As the sensorial maturity is only achieved at 4 to 5 years, the limits of ametropias are variable before that age. The majority of ametropias is constituted as early as 9 months and may be detected by a refractive examination under cycloplegia. This situation is especially true for hyperopia and astigmatism. The more important are initial ametropias the more unchanged they remain. At 9 months, 1 infant out of 5 present a non-physiological refraction. From 4 to 5 years, 1 child out of 4 needs a refractive correction. Significant myopias are uncommon in infants. They generally appear between 7 and 12 years.

Stereoacuity and ocular associations at age 12 years: findings from a population-based study

PURPOSE

To report the distribution of stereoacuity thresholds and ocular characteristics associated with reduced stereoacuity in a representative sample of 12-year-old Australian children.

METHODS

Stereoacuity thresholds were determined using the three quantitative plates of the TNO test in 2343 children, either unaided or with spectacles, if worn. Logarithm of minimum angle of resolution (logMAR) visual acuity was measured. Cycloplegic autorefraction (using cyclopentolate), cover testing, and dilated fundus examination were performed. Reduced stereoacuity was defined as > 120 arcsec. Myopia was defined as spherical equivalent refraction (SER) < or = -0.50 D hyperopia as spherical equivalent refraction > or = +2.0 D, anisometropia as spherical equivalent refraction difference between eyes > or =1.00 D, and astigmatism as cylinder > or = 1.0 D.

RESULTS

Stereoacuity was based on unaided visual acuity in 1975 children (84.3%) and on spectacle-corrected visual acuity in 368 children (15.7%); 87 children (3.7%) had reduced stereoacuity. Amblyopia was the most common identifiable cause, accounting for 32%, followed by strabismus (15%) and anisometropia (14%). Presence of anisometropia was significantly associated with reduced stereoacuity; 78.6% of anisometropic children achieved normal stereoacuity versus 98.9% without anisometropia (p < 0.0001).

CONCLUSIONS

Reduced stereoacuity was relatively uncommon in a population of 12-year-old Australian children. Its functional and psychosocial impact on individuals and on the whole population remains uncertain.

Primary intraocular lens implantation in the first two years of life: safety profile and visual results

PURPOSE

To study the safety profile of primary intraocular lens (IOL) implantation in the first two years of life.

MATERIALS AND METHODS

A prospective nonrandomized, interventional study was done at the tertiary care center. Forty-five eyes of 27 children (aged three weeks to two years) with congenital cataract who underwent phacoaspiration with continuous curvilinear capsulorrhexis combined with primary posterior capsulotomy and anterior vitrectomy with in the bag placement of IOL at primary surgery were included. Outcome measures were clarity of visual axis, postoperative inflammation, fixation pattern and retinoscopy.

RESULTS

The mean IOL power was 23.95 +/- 0.87 diopter (D) (range 22D to 27D). Follow-up ranged from 12 months to 48 months (mean 18 +/- 9.13 months). In infants, hypermetropia decreased from 6.60D +/- 2.64D at one week postoperatively to 3.03D +/- 2.53D at one year following surgery and 4.78D +/- 1.93D to 2.56D +/- 1.5D in children older than one year at the time of surgery. Re-opacification of the central visual axis was observed in six eyes (13.3%). Significant posterior synechiae due to irido-capsular adhesion was seen in seven eyes (15.6%). Five of these seven eyes also had significant posterior capsular opacification.

CONCLUSIONS

Meticulously performed primary IOL implantation and primary posterior capsulorrhexis with anterior vitrectomy in the first two years of life is a safe and effective method of aphakic correction.

Femtosecond laser in situ keratomileusis for consecutive hyperopia after radial keratotomy

PURPOSE

To assess the use of the femtosecond laser for laser in situ keratomileusis (LASIK) in eyes with consecutive hyperopia after radial keratotomy (RK).

SETTING

Private ambulatory surgical center, Valencia, Spain.

METHODS

This prospective noncomparative interventional case series study included 13 eyes of 9 patients with secondary hyperopia after previous RK. The patients were operated on with the IntraLase femtosecond laser (IntraLase Corp.) and the Star S2 excimer laser (Visx, Inc.). Postoperative uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, flap thickness, flap diameter, and complications were evaluated at 6 months.

RESULTS

The mean spherical equivalent (SE) decreased from 2.00 diopters (D)+/-0.40 (SD) to -0.41+/-0.61 D, with 8 eyes (61.5%) within+/-0.50 D of the targeted refraction. Twelve eyes (92.3%) had a UCVA of 20/40 or better, and 3 eyes (23.1%) lost 1 line of BSCVA. A mean change in SE of 0.10 D was observed at the 6-month follow-up. The mean flap thickness and diameter were 117+/-14 microm and 9.18+/-0.12 mm, respectively. Most complications were in eyes with more than 8 RK incisions than in eyes with 8 RK incisions. These complications were multiple intraoperative incision openings (100% versus 28.6%, respectively), interface inflammation (66.6% versus 0%, respectively), haze (83.3% versus 14.3%, respectively), and loss of BSCVA (50% versus 0%, respectively).

CONCLUSIONS

The femtosecond laser provided large, thin corneal flaps for hyperopic LASIK. However, the procedure should be avoided in eyes with more than 8 RK incisions because of the increased risk for multiple intraoperative incision openings, interface inflammation, haze, and loss of BSCVA.

Corneal Suture for the Correction of Hyperopia Following Radial Keratotomy

PURPOSE

To report the visual and refractive changes observed after double concentric corneal suture to correct hyperopic shift after radial keratotomy (RK).

METHODS

This retrospective consecutive case series comprised 17 eyes (15 patients) that underwent two concentric corneal sutures (modified Grene Lasso suture) to correct hyperopic shift after RK. All surgeries were performed by the same surgeon between 2000 and 2003.

RESULTS

The mean time after RK was 11.6 +/- 3.2 years. The mean follow-up was 20.3 +/- 11.3 months. The spherical equivalent refraction was reduced from a preoperative mean of +4.38 +/- 2.87 diopters (D) to -0.54 +/- 2.59 D at last postoperative follow-up (P < .001). No statistically significant difference was observed in mean refractive astigmatism before and after the corneal suture (P = .15). Before surgery, no eye presented with best spectacle-corrected visual acuity (BSCVA) > or = 20/20. At final follow-up, 3 (17.6%) eyes attained this level. Seven (41.2%) eyes improved their BSCVA by > or = 2 Snellen lines. One (5.9%) eye lost 2 Snellen lines of BSCVA.

CONCLUSIONS

Corneal suture can be used to correct RK-induced hyperopia, improving the corneal asphericity in an attempt to stabilize these corneas. It appeared to be effective even for high degrees of hyperopia and in cases with associated irregular astigmatism or open incisions.

Central toxic keratopathy: description of a syndrome in laser refractive surgery

PURPOSE

To describe the clinical spectrum of a syndrome in laser refractive surgery, which we call central toxic keratopathy, and to present cases that illustrate the range of this syndrome.

DESIGN

Retrospective observational case series.

METHODS

Eyes with noninflammatory central corneal opacification in the immediate postoperative period after photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) were identified, and the charts abstracted.

RESULTS

Twenty-three eyes of 14 patients were identified who developed central corneal opacification three to nine days after laser refractive surgery. Nineteen of these eyes had LASIK and four had PRK. All eyes had central corneal opacification in the area of laser treatment that extended posteriorly from the interface into the stromal bed (in the case of LASIK eyes). The opacification persisted a minimum of two months to a maximum of 18 months before clearing. Nine eyes developed postoperative hyperopia of greater than 2 diopters. Pre- and postoperative best-spectacle corrected acuity was available on 19 eyes; one of these eyes lost two lines of corrected acuity, and two other eyes lost one line. Eighteen of 19 LASIK eyes had diffuse lamellar keratitis preceding the onset of corneal opacification.

CONCLUSIONS

Central toxic keratopathy is characterized by noninflammatory central corneal opacification with a significant hyperopic shift. The opacification gradually clears over a period of months, leaving the eye hyperopic. Enhancement is indicated to treat residual hyperopia and remove residual striae. Topical or oral corticosteroid treatment is not indicated. The cause of central toxic keratopathy is unknown.

Genotype-phenotype correlation in a German family with a novel complex CRX mutation extending the open reading frame

PURPOSE

To describe the genotype-phenotype correlation in a German family with a novel CRX mutation and to perform a comparative analysis of published cases.

DESIGN

Retrospective observational case series, systematic review, and comparative analysis of the literature.

PARTICIPANTS

Four related patients with progressive retinal degeneration.

METHODS

Mutation screening by single-strand polymorphism analysis and direct sequencing. Clinical examination included kinetic visual fields (VFs), 2-color threshold perimetry (2CTP), full-field electroretinography, fundus photography, optical coherence tomography, and fundus autofluorescence (FA) recording.

MAIN OUTCOME MEASURES

Visual fields, subjective and objective cone- and rod-specific function, fundus aspect, retinal stratification, and FA.

RESULTS

A novel heterozygous complex mutation (c.816delCACinsAA) in CRX predicting the substitution of 27 C-terminal amino acids by 44 novel amino acids, thus abolishing the OTX tail, was identified in a 2-generation family finally diagnosed with cone-rod dystrophy (CRD), which was confirmed by 2CTP. Patients presented with variability in progression, nystagmus, and nyctalopia. Most of the patients were hyperopic. Electroretinography recordings showed residual rod and mixed cone-rod responses in 2 of the subjects. Age-dependent VF losses followed funduscopic changes of progressive atrophy of the retinal pigment epithelium and neuroretina in the macula and midperiphery marked by disturbed FA. Optical coherence tomography showed decreased central retinal thickness. Comparative analysis of the 131 published data sets revealed 2 groups: patients with early and late onset.

CONCLUSIONS

We described a 2-generation family with a novel mutation in CRX. The resulting phenotype is that of CRD with variable age at onset and progression. The phenotype description of previously published cases is conclusive only for CRD.