Clinical overview and treatment options for non-skeletal manifestations of mucopolysaccharidosis type IVA

Mucopolysaccharidosis type IVA (MPS IVA) or Morquio syndrome is a multisystem disorder caused by galactosamine-6-sulfatase deficiency. Skeletal manifestations, including short stature, skeletal dysplasia, cervical instability, and joint destruction, are known to be associated with this condition. Due to the severity of these skeletal manifestations, the non-skeletal manifestations are frequently overlooked despite their significant contribution to disease progression and impact on quality of life. This review provides detailed information regarding the non-skeletal manifestations and suggests long-term assessment guidelines. The visual, auditory, digestive, cardiovascular, and respiratory systems are addressed and overall quality of life as measured by endurance and other functional abilities is discussed. Impairments such as corneal clouding, astigmatism, glaucoma, hearing loss, hernias, hepatomegaly, dental abnormalities, cardiac valve thickening and regurgitation, obstructive sleep apnea, tracheomalacia, restrictive and obstructive respiratory compromise, and muscular weakness are discussed. Increased awareness of these non-skeletal features is needed to improve patient care.

Correlation of recognition visual acuity with posterior retinal structure in advanced retinopathy of prematurity

OBJECTIVE To compare Early Treatment Diabetic Retinopathy Study visual acuity outcome with retinal structural outcome at the 6-year follow-up examination of infants randomized in the Early Treatment for Retinopathy of Prematurity study. METHODS We compared the results in 606 eyes of subjects in whom both functional (visual acuity) and retinal structural assessments were obtained at age 6 years. Visual acuity assessments were performed by masked testers, and retinal examinations were performed by certified ophthalmologists. MAIN OUTCOME MEASURES Visual acuity and retinal structure at age 6 years. RESULTS Concordant outcomes occurred in 462 eyes (76.2%): 402 eyes had favorable functional and structural outcomes and 60 eyes had unfavorable functional and structural outcomes. Discordant outcomes occurred in 92 eyes (15.2%): 86 eyes had unfavorable functional and favorable structural outcomes and 6 eyes had favorable functional and unfavorable structural outcomes. Of the 86 eyes with unfavorable functional and favorable structural outcomes, 43 had optic atrophy (23 eyes) and/or retinal abnormalities that were less severe than those considered to be unfavorable (32 eyes). In 52 eyes (8.6%), retinal structure could not be assessed or the visual acuity was untestable. CONCLUSION Posterior pole appearance correlates well with visual acuity in 6-year-old infants with a history of advanced retinopathy of prematurity. APPLICATION TO CLINICAL PRACTICE When the retinal structure is normal but visual acuity is poor in infants with a history of severe retinopathy of prematurity, other diagnoses such as optic atrophy and cortical visual impairment could at least partially account for the discrepancy. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00027222.

Clinical guidelines for diagnosing and managing ocular manifestations in children with mucopolysaccharidosis

The mucopolysaccharidoses (MPS) are a group of rare lysosomal storage disorders characterized by the accumulation of glycosaminoglycans in several tissues and organs. This accumulation results in an array of clinical manifestations and premature death in severe cases. Ocular problems are very common in children with MPS and may involve the cornea, sclera, trabecular meshwork, retina, optic nerve and also the posterior visual pathways. The aims of this study are to give an overview of ocular problems in MPS and to provide clinical guidelines for paediatric ophthalmologists for early diagnosis and management of ocular manifestations in children with MPS. Diagnostic problems may arise in children with severe corneal clouding, hampering visualization of the fundus. Intraocular pressures may be falsely high, even leading to suspicion and unnecessary pressure-lowering treatment. Simple interventions such as the use of prescription glasses or photochromatic glasses can considerably improve quality of life in children with MPS.

Reading skills in children and adults with albinism: the role of visual impairment

PURPOSE

To evaluate whether visual impairment in albinism contributes significantly to the acquisition of normal reading skills.

METHODS

The authors administered standardized reading tests to 41 children and 18 adults with albinism. The Young Children's Achievement Test was used for children between 4 and 6 years old and the Woodcock-Johnson III was used for children 7 years and older and adults. Parents of children and adult subjects also completed a questionnaire to document developmental, academic, and/or work experiences. The Spearman test was used to evaluate the relationship between binocular best-corrected visual acuity (BCVA) and reading test results.

RESULTS

Standardized reading tests in both children and adults with albinism showed a normal distribution of scores. BCVA did not appear to play a significant role in the development of normal reading ability in these individuals who were visually impaired except for a mild correlation of decreased reading fluency on the Woodcock-Johnson III with decreased BCVA (r = 0.287, P = .046). Many young children with albinism had superior reading skills despite having a BCVA of 20/200 or worse (legal blindness).

CONCLUSION

This study of cognitively normal children and adults with albinism demonstrates that impaired vision during childhood does not by itself significantly impede a child's ability to acquire normal reading skills. However, the lower reading fluency that occurs in the more visually impaired individuals suggests they would benefit, both in the school system and workplace, with an accommodation involving more time to complete reading tasks.

Use of a Driving Simulator to Assess Performance under Adverse Weather Conditions in Adults with Albinism

Participants with albinism have reduced vision and nystagmus with reduced foveation times. This prospective study evaluated driving in 12 participants with albinism and 12 matched controls. Participants drove a vehicle simulator through a virtual rural course in sunny and foggy conditions. Under sunny conditions, participants with albinism showed a narrower preferred minimum safety boundary during car-following tasks than did controls, but there was no difference under foggy conditions. Their driving did not differ significantly from that of controls when approaching a stop sign or when choosing gap size between oncoming vehicles when crossing an intersection. However, when compared to control drivers, participants with albinism had a decreased minimum safety boundary for car-following that should be included in counseling regarding driving safety.

Change in visual acuity in albinism in the early school years

PURPOSE

To determine whether binocular best-corrected visual acuity (B-BCVA) improves in the early school years in patients with albinism and whether this is related to type of albinism, ocular pigment, or appearance of the macula.

METHODS

Patients with albinism seen between 5.5 and 9 years (Visit A) and 9.5 and 14 years of age (Visit B), with visits separated by at least 2.5 years, were included. Type of albinism, B-BCVA, glasses wear, iris pigment and macular transparency grade, and presence or absence of an annular reflex and melanin in the macula were recorded.

RESULTS

Mean B-BCVA was 20/84 at Visit A and 20/61 at Visit B (P < .001). B-BCVA improved in 80%. Improvement in B-BCVA and glasses wear, iris grade, macular grade, macular melanin, and annular reflex were weakly correlated. However, a moderate correlation was found between measured B-BCVA and iris grade at Visit A (r = 0.485, P < .001) and Visit B (r = 0.467, P < .001), and the presence of macular melanin at Visit A (r = 0.436, P < .001) and Visit B (r = 0.482, P < .001).

CONCLUSIONS

B-BCVA often improves in albinism in the early school years and this observation should be included in counseling. The etiology is unknown but may be related to change in nystagmus, use of precise null point, developmental maturation, and/or some of the ocular characteristics evaluated in this study.

Axenfeld-Rieger syndrome: new perspectives

Axenfeld-Rieger syndrome is a genetic disease affecting multiple organ systems. In the eye, this condition manifests with varying degrees of anterior segment dysgenesis and carries a high risk of glaucoma. Other associated systemic issues include cardiovascular outflow tract malformations, craniofacial abnormalities and pituitary abnormalities, which can result in severe endocrinological sequelae. Recent advances in molecular genetics have identified two major genes, PITX2 and FOXC1, demonstrating a wide spectrum of mutations, which aids in the molecular diagnosis of the disease, although evidence exists to implicate other loci in this condition. The management of individuals affected by Axenfeld-Rieger syndrome requires a multidisciplinary approach and would include dedicated surveillance and management of glaucoma, sensorineural hearing loss, and cardiac, endocrinological, craniofacial and orthopaedic abnormalities.

Ocular manifestations as key features for diagnosing mucopolysaccharidoses

Diagnosis of mucopolysaccharidosis (MPS) requires awareness of the multisystem disease manifestations and their diverse presentation in terms of time of onset and severity. Many patients with MPS remain undiagnosed for years and progressively develop irreversible pathologies, which ultimately lead to premature death. To foster timely treatment and ensure a better outcome, it is of utmost importance to recognize and evaluate the typical ocular features that present fairly early in the course of the disease in many children with MPS. These include corneal clouding, ocular hypertension/glaucoma, retinal degeneration, optic disc swelling and optic nerve atrophy. Other associations include pseudo-exophthalmos, amblyopia, strabismus and large refractive errors requiring spectacle correction. While some ocular manifestations require specialized equipment for detecting abnormalities, light sensitivity, pseudo-exophthalmos and strabismus are often apparent on a routine physical examination. In addition, patients may be symptomatic from vision impairment, photosensitivity, night blindness and visual field constriction. Combined with the skeletal/joint complications and other manifestations, these ocular features are key in the differential diagnosis of children with joint abnormalities. Rheumatologists should have a high index of suspicion for MPS to facilitate early diagnosis. Referral to a geneticist, a metabolic specialist or physician who specializes in MPS can confirm the diagnosis and provide disease management. Consultation with an ophthalmologist who has expertise in MPS is also needed for thorough examination of the eyes and regular follow-up care.

Grating visual acuity results in the early treatment for retinopathy of prematurity study

OBJECTIVE

To compare grating (resolution) visual acuity at 6 years of age in eyes that received early treatment (ET) for high-risk prethreshold retinopathy of prematurity (ROP) with that in eyes that underwent conventional management (CM).

METHODS

In a randomized clinical trial, infants with bilateral, high-risk prethreshold ROP (n = 317) had one eye undergo ET and the other eye undergo CM, with treatment only if ROP progressed to threshold severity. For asymmetric cases (n = 84), the high-risk prethreshold eye was randomized to ET or CM.

MAIN OUTCOME MEASURE

Grating visual acuity measured at 6 years of age by masked testers using Teller acuity cards.

RESULTS

Monocular grating acuity results were obtained from 317 of 370 surviving children (85.6%). Analysis of grating acuity results for all study participants with high-risk prethreshold ROP showed no statistically significant overall benefit of ET (18.1% vs 22.8% unfavorable outcomes; P = .08). When the 6-year grating acuity results were analyzed according to a clinical algorithm (high-risk types 1 and 2 prethreshold ROP), a benefit was seen in type 1 eyes (16.4% vs 25.2%; P = .004) undergoing ET, but not in type 2 eyes (21.3% vs 15.9%; P = .29).

CONCLUSION

Early treatment of eyes with type 1 ROP improves grating acuity outcomes, but ET for eyes with type 2 ROP does not. APPLICATION TO CLINICAL MEDICINE: Type 1 eyes should be treated early; however, based on acuity results at 6 years of age, type 2 eyes should be cautiously monitored for progression to type 1 ROP. Trial Registration clinicaltrials.gov Identifier: NCT00027222.

Outcome of penetrating keratoplasty for mucopolysaccharidoses

OBJECTIVE

To describe the outcome of penetrating keratoplasty (PK) for corneal opacification in the setting of systemic mucopolysaccharidoses (MPS).

METHODS

A consecutive case series and literature review.

RESULTS

Eight eyes from 5 patients with MPS (MPS I, MPS IV, and MPS VI) and a history of PK met inclusion criteria for our case series at the University of Minnesota Medical Center. The mean age at the time of PK was 40.5 years (range, 11.7-65.3 years). Mean follow-up time after the PK was 4.9 years (range, 1-11 years). Mean (SD) visual acuity before PK was 0.90 (0.38) logMAR. The mean (SD) visual acuity at the last visit for all 8 eyes was 0.32 (0.16) logMAR. Visual acuity improved in 7 of 8 eyes (P = .002). Although early rejection led to repeat PK in 1 eye, no recurrent opacity consistent with MPS was noted in any of the corneal grafts. In a literature review, we found 23 reports documenting 40 initial and 3 repeat cases of PK in the setting of MPS. Of these, 31 initial and 2 repeat corneal grafts were reportedly clear during follow-up, ranging from 0.25 to 13 years.

CONCLUSIONS

Penetrating keratoplasty is often a beneficial intervention in appropriate patients with corneal clouding due to MPS. Improvement in vision can be obtained with stable, clear corneal grafts in this population.

Reading acuity in albinism: evaluation with MNREAD charts

INTRODUCTION

The MNREAD reading acuity (RA) charts use continuous-text reading to measure (1) RA, ie, the smallest size of print that the patient can resolve; (2) maximum reading speed (MRS); and (3) critical print size (CPS), ie, the smallest print that the patient can read with maximum speed. This project used the MNREAD charts to evaluate reading performance in children and adults with albinism to determine the smallest print size recommended to facilitate effortless reading.

METHODS

A total of 63 subjects with albinism were administered the MNREAD test to determine the critical print size for effortless reading. The subjects read continuous, high-contrast text print until they could no longer discern the words. The MRS and CPS were determined with the MNREAD protocol. Presence or absence of nystagmus and strabismus was recorded. Distance visual acuity was measured with ETDRS charts.

RESULTS

The sample included 25 male and 38 female subjects with a median age of 16 years. Median MRS was 150 words per minute. The mean CPS was 0.84 logMAR, notably larger than the mean RA of 0.53 logMAR.

CONCLUSIONS

The MNREAD acuity charts can be used to determine functional reading ability and critical print size for effortless reading in individuals with albinism. The amount of enlargement in print size can be used in educational and vocational recommendations to facilitate reading.

Diagnosis and management of ophthalmological features in patients with mucopolysaccharidosis

Ocular pathology is common in patients with mucopolysaccharidosis (MPS), a hereditary lysosomal storage disorder, where the eye as well as other tissues accumulate excessive amounts of glycosaminoglycans. Despite genetic and phenotypic heterogeneity within and between different types of MPS, the disease symptoms and clinical signs often manifest during the first 6 months of life with increasing head size, recurrent infections, umbilical hernia, growth retardation and skeletal problems. Typical ocular features include corneal clouding, ocular hypertension/glaucoma, retinal degeneration and optic nerve atrophy. Visual deterioration and sensitivity to light may substantially reduce the quality of life in MPS patients, particularly when left untreated. As an early intervention, haematopoietic stem cell transplantation and/or enzyme replacement therapy are likely to improve patients' symptoms and survival, as well as visual outcome. Thus, it is of utmost importance to ensure proper detection and accurate diagnosis of MPS at an early age. It is of fundamental value to increase awareness and knowledge among ophthalmologists of the ocular problems affecting MPS patients and to highlight potential diagnostic pitfalls and difficulties in patient care. This review provides insight into the prevalence and severity of ocular features in patients with MPS and gives guidance for early diagnosis and follow-up of MPS patients. MPS poses therapeutic challenges in ocular management, which places ophthalmologists next to paediatricians at the forefront of interventions to prevent long-term sequelae of this rare but serious disease.

Periocular granuloma annulare in four children

Subcutaneous granuloma annulare is a skin condition that occurs on the lower extremities, hands, and scalp of healthy children. It rarely occurs in the periocular area, and when it does, the annular pattern is often absent. Histopathology is diagnostic and shows palisading histiocytes around areas of necrobiosis. Although benign in nature, the lesions tend to multiply, grow in size, and often recur. They usually resolve spontaneously and do not require treatment. Four cases of periocular subcutaneous granuloma annulare, from four different geographical areas, were identified through on-line postings on the worldwide mailing list of the Organization for Pediatric Ophthalmology and Strabismus (http://lists.ucsd.edu/mailman/listinfo/ped-ophth-1). These 4 patients are reported here, and a brief review of the literature is presented.

Outcome of angle surgery in children with aphakic glaucoma

PURPOSE

To investigate the outcome of trabeculotomy and/or goniotomy for pediatric aphakic glaucoma.

METHODS

Retrospective chart review of consecutive children who had congenital cataract surgery between 1990 and 2006 and required goniotomy and/or trabeculotomy for aphakic glaucoma. Treatment success was defined as postoperative intraocular pressure of <or=24 mm Hg despite topical medication use, avoidance of trabeculectomy or shunt placement, and no visually significant complications in the follow-up period. Exclusion criteria included a diagnosis of anterior segment dysgenesis, microcornea, and glaucoma at the time of cataract surgery, and follow-up less than 1 year.

RESULTS

A total of 14 eyes of 11 patients met inclusion criteria, with a mean follow-up of 4.7 years. Of theses, 2 eyes had goniotomy alone, 3 eyes had goniotomy followed by trabeculotomy, and 9 eyes had trabeculotomy alone. Mean IOP before angle surgery was 35 +/- 10 mm Hg. Mean IOP at the last recorded visit was 22 +/- 4 mm Hg (p = 0.0005). Treatment success was observed in 8 of the 14 eyes (57.1%), with a mean number of angle procedures of 1.4 per eye: 6 eyes (42.8%) were successful after a single angle surgery, each involving an initial trabeculotomy; 3 eyes (21.4%) underwent subsequent shunt placement after initial goniotomy at 6 months, 1.3 years, and 5.5 years after the last angle surgery.

CONCLUSIONS

When intraocular surgery is indicated to control IOP in pediatric aphakic glaucoma, trabeculotomy and/or goniotomy can be successful in the majority of eyes and may decrease the need for filtering and shunting procedures.

Arrested development: high-resolution imaging of foveal morphology in albinism

Albinism, an inherited disorder of melanin biosynthesis, disrupts normal retinal development, with foveal hypoplasia as one of the more commonly associated ocular phenotypes. However the cellular integrity of the fovea in albinism is not well understood - there likely exist important anatomical differences that underlie phenotypic variability within the disease and that also may affect responsiveness to therapeutic intervention. Here, using spectral-domain optical coherence tomography (SD-OCT) and adaptive optics (AO) retinal imaging, we obtained high-resolution images of the foveal region in six individuals with albinism. We provide a quantitative analysis of cone density and outer segment elongation demonstrating that foveal cone specialization is variable in albinism. In addition, our data reveal a continuum of foveal pit morphology, roughly aligning with schematics of normal foveal development based on post-mortem analyses. Different albinism subtypes, genetic mutations, and constitutional pigment background likely play a role in determining the degree of foveal maturation.

Evaluation of vision-specific quality-of-life in albinism

INTRODUCTION

Human albinism is a genetic condition associated with visual impairment that affects many aspects of daily life. Office measurements of visual acuity do not necessarily reflect daily visual function and health status. This study used the National Eye Institute Visual Function Questionnaire (NEI-VFQ) to determine the effect of albinism-associated ophthalmopathy on quality of life (QOL).

METHODS

We administered the NEI-VFQ, which consists of 25 questions about QOL (VFQ-25) and 14 questions about well-being (VFQ-39), to 44 consenting participants with albinism older than the age of 18 years.

RESULTS

Nineteen male and 25 female subjects completed the study. Median age was 30.5 years (range, 18-79 years). Mean best-corrected visual acuity was 20/83 (range, 20/20 to 20/320). Forty-eight percent reported that they were currently able to drive with their condition. Participants perceived midscale problems with their general vision (median subscale score 60.0). Visual acuity correlated moderately with overall NEI-VFQ composite scores (r(s) = 0.40, p = 0.01 for VFQ-25 and r(s) = 0.36, p = 0.02 for VFQ-39). Most notable impairment was recorded for distance acuity, vision-specific mental health, and vision-specific role difficulties (VFQ-39 median subscale scores 66.7, 70.0, and 75.0, respectively). Differences by sex were insignificant. Greater ceiling effects were noted for the VFQ-25 than for the VFQ-39.

CONCLUSIONS

The NEI-VFQ-39 is a method to evaluate self-reported effects of vision-related QOL in albinism and may be used as a baseline for evaluating outcomes in interventional studies in these patients.

The prevalence of attention-deficit/hyperactivity disorder among persons with albinism

Attention-deficit/hyperactivity disorder (ADHD) is a common diagnosis in children and adults. Human albinism is an uncommon genetic condition associated with visual impairment that may affect behavior. To determine if there is a relationship between albinism and ADHD, the prevalence of ADHD was examined among 78 children (age range, 4-18 years) and among 44 adults (age range, 19-79 years) with ocular or oculocutaneous albinism. ADHD was diagnosed in the pediatric population using a combination of Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) criteria, Conners' Parent Rating Scale, and physician observation. Adults were diagnosed using the Utah criteria for ADHD as confirmed by physician history and interview. Seventeen children (22.7% [17 of 75]) (3 children with existing diagnoses of pervasive developmental disorder were identified but were not included in the data analysis) and 3 adults (6.8%) met the criteria for ADHD. The combined hyperactivity and impulsivity subtype of ADHD was most common, accounting for 50% of the diagnoses. Binocular best-corrected visual acuity and genetic type of albinism were not found to correlate with a diagnosis of ADHD. The prevalence of ADHD among children and adults with albinism is more frequent than that reported among the general population and is not related to binocular best-corrected visual acuity.

Sectoral iris heterochromia and retinal pigment variation in 13q-syndrome

Chromosome 13q deletion syndrome is characterized by growth retardation, cognitive delays, and organ and musculoskeletal deformities. Typical ocular associations include retinoblastoma, microphthalmia, and colobomas. We report a case of bilateral iris heterochromia and retinal pigment abnormalities in a child with 13q-syndrome.

Spectrum of foveal development in albinism detected with optical coherence tomography

BACKGROUND

Optical coherence tomography (OCT) has shown the absence of a foveal depression in an individual with oculocutaneous albinism, type 1 (OCA1) and best-corrected visual acuity (BCVA) of 20/400. However, the presence of an annular light reflex in the macula has been noted with indirect ophthalmoscopy in other patients with albinism who have better vision. We studied macular architecture in albinism with OCT when binocular BCVA was > or = 20/60 and compared this to detection of foveal development with binocular indirect ophthalmoscopy.

METHODS

Eleven patients with albinism and BCVA > or = 20/60 were recruited for OCT. Average central macular thickness was recorded. Presence of an oval annular reflex was determined with binocular indirect ophthalmoscopy.

RESULTS

Mean binocular BCVA was 20/39 (range: 20/20 to 20/50). Twelve eyes had a rudimentary annular reflex detected with ophthalmoscopy. OCT was reliable in 20 of 22 eyes. A foveal depression was identified with OCT in four eyes. Mean macular thickness for these four eyes was 233 microm (+/- 22.5 microm). We found a weak inverse correlation between BCVA (logMAR) and thickness (r = -0.21).

CONCLUSIONS

OCT shows the spectrum of foveal development in albinism, from complete absence of development to a central depression corresponding to a rudimentary annular reflex detected with ophthalmoscopy. The reduced rate of detection of foveal development with OCT compared with ophthalmoscopy is likely related to poor fixation in patients with nystagmus.

Strabismus and amblyopia in bilateral Peters anomaly

BACKGROUND

Peters anomaly is a rare form of anterior segment dysgenesis in which abnormal cleavage of the anterior chamber occurs at the end of the third week of gestation. We examined the prevalence of strabismus and amblyopia and analyzed predictive factors for their development, as well as the visual outcome and associated anomalies in patients with bilateral Peters anomaly.

METHODS

Using a retrospective review, we identified 25 consecutive patients with bilateral Peters anomaly who were observed between August 1995 and February 2005. Ocular structural and systemic anomalies, amblyopia therapy, visual acuity, and binocular alignment at last visit were recorded. Fisher's exact test was used to identify any association between defined predictive factors and the development of strabismus.

RESULTS

Mean follow-up time was 5.1 year (range, 0.5-21 years). Median age at presentation was 2.5 months (range, 1 day to 13 years). Penetrating keratoplasties were performed on 34 eyes in 20 patients. Final best-corrected visual acuity ranged from 20/25 to no light perception. Thirteen of 18 patients with recorded motility (72%) developed strabismus: esotropia (n = 7), exotropia (n = 5), and variable (n = 1); one also had dissociated vertical deviation. Patients with equal vision were either orthophoric (n = 4) or had intermittent esotropia (n = 1), whereas strabismus occurred in 100% of patients whose vision was asymmetric by more than 1.5 octaves. Asymmetric vision was the only statistically significant predictive factor for the development of strabismus (P = 0.002). Amblyopia treatment resulted in improved vision in 3 of 5 patients.

CONCLUSION

Strabismus occurs frequently in bilateral Peters anomaly. Asymmetric vision, (because of ocular structural anomalies) postoperative complications, and amblyopia may predispose to strabismus. Despite ocular structural limitations, amblyopia therapy is recommended in the aggressive rehabilitation of these eyes.

Correlation of grating acuity with letter recognition acuity in children with albinism

PURPOSE

This study was undertaken to determine whether grating acuity in early childhood can be used as a predictor of letter recognition acuity in patients with albinism.

METHODS

In this retrospective study, we compared the binocular grating acuities of children with albinism (30 at age 1, 29 at age 2, and 19 at age 3) to their letter recognition acuity at age 4-6 years.

RESULTS

Mean binocular grating acuity was 2.0, 1.9, and 1.5 octaves below age matched norms at ages 1, 2, and 3 years, respectively (P<0.001 at all ages). Mean grating acuity at ages 1, 2, and 3 correlated moderately (r=0.458, 0.502, and 0.471, respectively; all with P<0.05) with mean binocular letter recognition acuity of the same children at ages 4-6. A subgroup analysis of 9 patients followed longitudinally showed strong correlation of binocular grating acuity at ages 1 and 2 with letter acuity (r=0.745, P=0.021; r=0.930, P<0.001, respectively) and moderate correlation at age 3 (r=0.685, P=0.042). In the larger group and the longitudinal subgroup, mean binocular grating acuity at ages 1 and 2 was worse than mean binocular letter recognition acuity at age 4-6 (paired-samples t-test, P<0.001). Mean binocular grating acuity at age 3 in both groups was not significantly different than mean binocular letter recognition acuity at age 4-6 (paired-samples t-test, P=0.790, 0.215, respectively).

CONCLUSION

Parents should be informed that vision measured as grating acuity at age 3 provides an estimate of future letter recognition acuity in children with albinism.