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Biomedical subjects

I C Lloyd

Publications and source records attributed to I C Lloyd.

At least 19 recordsLinked to original sources
PubMed2006

Refractive outcomes after primary intraocular lens implantation in infants.

BACKGROUND: Intraocular lens (IOL) implantation is becoming increasingly accepted as a primary procedure in infants. AIM: To evaluate the accuracy of IOL power calculation, the rate of myopic shift and the refractive outcome after primary IOL implantation in infants aged <12 months at the time of cataract surgery. METHOD: A retrospective case review of 25 patients (8 with bilateral cataracts and 17 with unilateral cataracts) who underwent cataract surgery with primary IOL implantation at <12 months of age. Outcomes measured were actual early postoperative refraction, lens power calculation error, myopic shift and refractive outcome. RESULTS: In 83% of cases, actual postoperative refraction was within 2 dioptres (D) of the target refraction. Lens power calculation error did not depend on axial length, age at surgery or target refraction. Mean (SD) myopic shift was 5.43 (3.7) D in the first 12 months after surgery, but was significantly greater when surgery was performed at <10 weeks of age. CONCLUSION: This study demonstrates that IOL power can be calculated with reasonable accuracy in infants using current formulas. Factors such as age at the time of surgery, axial length, whether surgery is unilateral or bilateral, and the presence of systemic pathologies do not seem to influence the accuracy of lens power calculation or myopic shift up to 36 months of age.

Age Factors↗
PubMed2006

The ocular features of the mucopolysaccharidoses.

AIMS: The mucopolysaccharidoses (MPS) are a heterogeneous group of rare disorders characterised by accumulation of glycosaminoglycans within multiple organ systems. This study aimed to determine the prevalence and severity of ocular complications in patients with MPS. METHODS: Clinical ophthalmic features and electrodiagnostic results of 50 patients with a diagnosis of MPS were retrospectively reviewed. RESULTS: A total of 79% of MPS IH patients had a visual acuity of less than 6/12 equivalent in their better eye, compared to 44% of MPS IH/S and 25% of MPS VI patients. In total, 16% of MPS IH and 25% of MPS IH/S had severe corneal opacification, compared to 38% of MPS VI patients. 16% of MPS IH patients had optic atrophy; 21% of MPS VI patients had mild disc swelling, 29% had markedly swollen discs, and 14% had optic atrophy. One patient with MPS IH, one with MPS IH/S and six with MPS VI had ocular hypertension. One MPS VI patient had glaucoma that required topical therapy. Nine patients with MPS IH had electrodiagnostic evidence of retinopathy, as did one MPS VI patient. CONCLUSIONS: Ocular complications causing significant reduction in vision are common in MPS. The majority of MPS I and MPS VI patients have corneal opacification, which can lead to difficulties in diagnosis and monitoring of glaucoma, optic disc changes, and retinopathy.

Adolescent↗
PubMed2006

Grading infantile cataracts.

PURPOSE: To introduce and describe two methods of grading the severity of infantile cataracts, and thereby propose a useful clinical guide for early surgical intervention. METHODS: Thirty-three subjects, aged 1 week to 8 years, participated in the study. Twenty-two were evaluated soon after birth (1 week), and 11 in childhood (3-8 years). All had isolated infantile cataracts, of which 16 were bilateral and 17 unilateral. Nine cataract types were examined; nuclear (n = 9), lamellar (n = 9), posterior lenticonus (n = 4), persistent hyperplastic primary vitreous (n = 4), posterior polar (n = 3) and single cases of total, cortical, sutural and anterior polar. Grading the infantile cataracts was performed subjectively based on the cataract morphology, density and position using an 11-point (0-10) ordinal scale. Objective measures of the cataracts were performed by scanning and then digitising photo-slit lamp images to provide cataract intensity profiles. Subjects without cataracts acted as controls. RESULTS: Subjective gradings of 0 and 10 were assigned to the clear, cataract-free lens and the total cataract, respectively. Fixed grades of 1 (anterior polar, sutural) and 6 (posterior polar) were assigned to the three remaining cataracts with static morphologies. The five cataracts which were all progressive were given grading ranges, reflecting the initial and likely final morphological states. Objective measures were found to be valuable in indicating the exact position and relative density of the cataract, as well as accurately defining boundaries. CONCLUSIONS: The magnitude and severity of infantile cataracts can be usefully characterised by an 11-point ordinal subjective grading scale. Although subjective grading alone is satisfactory, it can be greatly assisted by objective measures, particularly in the documentation of cataract progression. Cataracts assigned grades 1-4 were considered minor obstructions to vision and therefore not candidates for early surgery. Cataracts graded 5 and above were considered major visual defects, and ideally should be removed early in life.

Cataract↗
PubMed2005

Bimedial hang-back recession -- outcomes and surgical response.

AIM: To report outcomes and identify factors affecting surgical response for constant esotropia using 'hang-back' bimedial rectus recession. STUDY TYPE: Retrospective case series analysis. METHODS: Patients managed by a single surgeon over a 4-year study period were categorized into esotropia types: infantile, partially accommodative, nonaccommodative and secondary esotropia. Postoperative alignment was compared between types, and regression modelling used to examine factors predicting surgical response. RESULTS: In all, 95% (18/19) of children with partially accommodative esotropia achieved postoperative deviation <15 prism dioptres from orthotropia, compared to 56% (15/27) of children with infantile esotropia, 69% (11/16) of children with non-accommodative esotropia and all (2/2) of those with secondary esotropia. Surgical response (Delta/mm recession performed) increased with the magnitude of both preoperative deviation (P<0.001) and anisometropia (P<0.001); the effect of deviation on surgical response was reduced by amblyopia (P=0.02). Age at surgery was statistically associated (P=0.002) but had negligible clinical effect on response. CONCLUSIONS: Surgical response to hang-back recession may be partially predicted by preoperative factors.

Accommodation, Ocular↗
PubMed2004

Autosomal dominant brachydactyly, coloboma and anterior segment dysgenesis.

A three-generation family presenting with ocular developmental abnormalities, including anterior segment dysgenesis and coloboma, associated with brachydactyly and clinodactyly is presented. Several conditions incorporating ocular and bony limb abnormalities have been described. However, we believe that this family manifests a previously undescribed syndrome due to autosomal dominant or possibly x-linked inheritance with variable expression.

Adult↗
PubMed2004

Primary IOL implantation in children: a risk analysis of foldable acrylic v PMMA lenses.

BACKGROUND: /aims: To compare the relative risks of poly (methylmethacrylate) (PMMA) and soft acrylic (AcrySof) primary intraocular lens (IOL) implantation in paediatric cataract surgery. METHODS: A retrospective analysis of clinical data was performed on eyes of 61 infants and children who underwent cataract surgery with primary IOL implantation. Age at operation ranged from 3 weeks to 15 years. Mean follow up duration was 24.5 months (range 0.5-68 months). Factors examined included type of IOL (PMMA, acrylic), performance of a primary posterior continuous curvilinear capsulorhexis (PCCC) or capsulotomy with limited anterior vitrectomy, perioperative complications, and subsequent intervention for posterior capsule opacification (PCO). Risk factors for perioperative complications were examined with 2x2 tables to give odds ratios (OR) as measures of association. A survival analysis was performed to assess risk of subsequent intervention for PCO with different IOL types. Relative risks (hazards) and confidence intervals (CI) were calculated with Cox regression to adjust for potential confounding. RESULTS: Compared to acrylic, PMMA IOLs were significantly associated with perioperative complications (OR 5.2, 95% CI 1.4 to 19, p = 0.01). However, IOL and type of section were highly correlated factors, and this finding may reflect risks associated with larger scleral wounds used for PMMA IOLs. No statistically significant difference in risk of subsequent intervention for PCO was found between different IOL types. Mean times till intervention for PMMA and acrylic IOLs were 30.1 months (95% CI 22 to 38) and 19.8 months (95% CI 12 to 27) respectively (log rank test statistic 1.53, one degree of freedom, p = 0.22). At 12 months post-implant surgery, 76% (95% CI 59 to 93) of PMMA cases and 54% (95% CI 35 to 72) of acrylic cases had not required intervention for PCO; these proportions fell to 55% (95% CI 35 to 75) and 38% (95% CI 14 to 61) for PMMA and acrylic cases respectively at 2 years post-surgery. After adjustment for age at surgery, primary posterior capsulorhexis, and perioperative complications relative risk of intervention after acrylic IOL implantation was 1.6 (95% CI 0.66 to 3.9, p = 0.29). CONCLUSION: Primary implantation of foldable soft acrylic IOLs in paediatric eyes may allow fewer perioperative complications than rigid PMMA IOLs. Short term safety profiles of primary implantation in paediatric cataract surgery are otherwise comparable for PMMA and soft acrylic IOLs.

Acrylic Resins↗
PubMed2003

Endocrine status in patients with optic nerve hypoplasia: relationship to midline central nervous system abnormalities and appearance of the hypothalamic-pituitary axis on magnetic resonance imaging.

We here: 1) describe the phenotypic spectrum, including magnetic resonance imaging (MRI) appearances of the pituitary stalk and anterior and posterior pituitary [H-P (hypothalamic-pituitary) axis], in children with optic nerve hypoplasia (ONH) with or without an abnormal septum pellucidum (SP); and 2) define endocrine dysfunction according to the MRI findings. Medical records of 55 children with ONH who had been assessed by ophthalmology and endocrine services were reviewed. All had MRI of the brain and H-P axis. Forty-nine percent of the ONH patients had an abnormal SP on MRI, and 64% had a H-P axis abnormality. Twenty-seven patients (49%) had endocrine dysfunction, and 23 of these had H-P axis abnormality. The frequency of endocrinopathy was higher in patients with an abnormal SP (56%) than a normal SP (39%). Patients were divided into four groups based on SP and H-P axis appearance: 1) both normal; 2) abnormal SP and normal H-P axis; 3) normal SP and abnormal H-P axis; and 4) both abnormal. The frequency of multiple pituitary hormone deficiency was highest (56%) in group 4, lower (35%) in group 3, and even lower (22%) in group 2. Precocious puberty was most common in group 2. None of the patients in group 1 had endocrine dysfunction. Thus, SP and H-P axis appearances on MRI can be used to predict the likely spectrum of endocrinopathy.

Adolescent↗
PubMed2002

Association of the congenital bone marrow failure syndromes with retinopathy, intracerebral calcification and progressive neurological impairment.

We present a child with Fanconi anaemia and congenital hypopituitarism, who developed intracerebral calcifications, progressive spasticity and retinopathy. The chromosome fragility with mitomycin C was increased in both the patient and his sibling, confirming a diagnosis of Fanconi anaemia. Aplastic anaemia in association with intracerebral calcifications has been described in patients with dyskeratosis congenita and Revesz syndrome, but not so far in confirmed cases of Fanconi anaemia. This case further illustrates the greater overlap of associated features in congenital bone marrow failure syndromes. It also indicates that Fanconi anaemia should be actively excluded where such associated features are found.

Adolescent↗
PubMed2002

The ophthalmic findings in Cohen syndrome.

AIM: Cohen syndrome is an uncommon autosomal recessive condition comprising a characteristic facial appearance, mental retardation, benign neutropenia, and retinal dystrophy. This study aimed to identify patients with Cohen syndrome from across the United Kingdom in order to define the variability of ophthalmic manifestations. METHODS: Ophthalmic assessment was undertaken and past ophthalmic records reviewed in 22 patients with classic features of Cohen syndrome. RESULTS: All patients had visual problems which commonly started in the preschool years. 82% developed strabismus or refractive error during the first 5 years of life. 70% developed high myopia by the second decade. By contrast with the findings of others, early onset retinal dystrophy was common, occurring in 80% of study patients under age 5 years. 35% of patients were registered partially sighted or blind. CONCLUSION: The ophthalmic abnormalities associated with Cohen syndrome, including high myopia and a generalised, severe retinal dystrophy, are of early onset and frequently result in severe visual handicap. Cohen syndrome should be considered in the young, developmentally delayed child who presents with severe myopia and nyctalopia.

Adolescent↗
PubMed2001

A clinical evaluation of random dot stereoacuity cards in infants.

PURPOSE: To clinically evaluate the random dot stereoacuity cards developed by Birch and Salomao on a population of infants within the first 12 months of life and to generate baseline normative data. METHODS: Random dot stereoacuity cards were constructed using vectographic vertical bar stimuli with cross disparities ranging from 45 to 1735 seconds of arc (1.65 to 3.2 log seconds of arc). Wearing polarising goggles, infants were assessed using a two-alternative forced choice preferential looking staircase procedure. Success rate and stereoacuity values for performance as a function of age were evaluated. RESULTS: One hundred and seventy-seven tests were completed on 41 infants with ages ranging from 5 to 56 weeks. The random dot stereoacuity procedure was successful in 128 (72.3%) infants, success being dependent upon age. At 0-8 weeks of age, none of the infants produced a fixation preferance towards even the coarsest stereogram. The success rate increased to 50% at 9-16 weeks, 97% at 17-24 weeks, 93% at 25-36 weeks, dropping to 69% at 37-56 weeks due to increasing intolerance to the goggles. Stereopsis was not demonstrable in infants under 8 weeks of age. By 9-16 weeks the mean stereoacuity level was 2.91 log seconds of arc, further increasing to 2.53 at 17-24 weeks, reducing slightly to 2.65 at 25-36 weeks. At 37-56 weeks the mean stereoacuity value was recorded as 2.53 log seconds of arc. CONCLUSION: Our results indicate that the infant random dot stereoacuity cards provide a simple, quick and portable test for the clinical assessment of stereopsis in infants aged between 17 and 36 weeks, and should prove to be a useful clinical tool to monitor infants at risk of binocular vision disorders.

Age Factors↗
PubMed2001

Accuracy of intraocular lens power calculation in paediatric cataract surgery.

AIMS: To determine the accuracy of intraocular lens (IOL) power calculation in a group of pseudophakic children. METHODS: A retrospective analysis of biometric and refractive data was performed on 52 eyes of 40 infants and children, who successfully underwent cataract extraction and IOL implantation. The following parameters were included: age at the time of surgery, keratometry, axial length, estimated refraction, and the power of IOL implanted. The postoperative refractive outcome was taken as the spherical equivalent of the refraction at 3 months after surgery. The prediction error was taken as the absolute difference between the estimated and actual postoperative refraction. The data were analysed to assess the effects of age at the time of surgery, keratometry, and axial length on the accuracy of calculation of IOL power. RESULTS: For the overall group the mean and median prediction errors were 1.40 D and 0.84 D (SD 1.60). The mean and median prediction errors in eyes with axial lengths > or =20 mm were 1.07 D and 0.71 D (SD 0.98) and in eyes <20 mm were 2.63 D and 2.61 D (SD 2.65). The mean and median prediction errors in eyes in children aged > or =36 months were 1.06 D and 0.68 D (SD 1.02) and in children aged <36 months was 2.56 D and 2.29 D (SD 2.50). The differences between the prediction errors for both axial length and age were statistically significant (p<0.05). CONCLUSIONS: For the overall group IOL power calculation is satisfactory. In eyes with axial lengths less than 20 mm and in children less than 36 months of age larger errors can arise. This study demonstrates the need for an IOL formula specifically designed for paediatric use.

Adolescent↗
PubMed2000

Apple peel atresia in association with bilateral colobomatous malformation of the optic nerve heads, dysmorphic features, and learning disability - a new syndrome?

Apple peel atresia of the small bowel is a rare congenital cause of intestinal obstruction. This case report describes a male patient with apple peel atresia and bilateral colobomatous malformation of the optic nerve heads in association with dysmorphic features and learning disabilities. In the absence of a positive family history, we propose that this collection of clinical findings could be due to a new dominant mutation or chromosomal microdeletion.

Child↗
PubMed2000

Phenotypic variability and asymmetry of Rieger syndrome associated with PITX2 mutations.

PURPOSE: Rieger syndrome is an autosomal dominant condition characterized by a variable combination of anterior segment dysgenesis, dental anomalies, and umbilical hernia. To date, reports have shown mutations within the PITX2 gene associated with Rieger syndrome, iridogoniodysgenesis, and iris hypoplasia. The purposes of this study were to determine the range of expression and intrafamilial variability of PITX2 mutations in patients with anterior segment dysgenesis. METHODS: Seventy-six patients with different forms of anterior segment dysgenesis were classified clinically. DNA was obtained and screened by means of polymerase chain reaction (PCR)-single-stranded conformation polymorphism (SSCP) and heteroduplex analysis followed by direct sequencing. RESULTS: Eight of 76 patients had mutations within the PITX2 gene. Anterior segment phenotypes show wide variability and include a phenocopy of aniridia and Peters', Rieger, and Axenfeld anomalies. Mutations include premature terminations and splice-site and homeobox mutations, confirming that haploinsufficiency the likely pathogenic mechanism in the majority of cases. CONCLUSIONS: There is significant phenotypic variability in patients with PITX2 mutations, both within and between families. Developmental glaucoma is common. The umbilical and dental abnormalities are highly penetrant, define those at risk of carrying mutations in this gene, and guide mutation analysis. In addition, there is a range of other extraocular manifestations.

Anterior Eye Segment↗
PubMed2000

Optic atrophy in association with cobalamin C (cblC) disease.

PURPOSE: To report the association of optic atrophy with cobalamin C (cblC) disease. METHODS: Descriptive case reports on three patients, two of whom were siblings. RESULTS: All three patients with cblC disease exhibited bilateral optic atrophy with decreased visual acuity. Of the two siblings, the younger sister had received cobalamin supplements from birth and the mother had been given cobalamin supplements prenatally. CONCLUSION: These three cases confirm the association of optic atrophy with cblC disease. Early treatment with cobalamin supplements does not appear to prevent the development of optic atrophy.

Age of Onset↗
PubMed1999

Coats' disease of the retina (unilateral retinal telangiectasis) caused by somatic mutation in the NDP gene: a role for norrin in retinal angiogenesis.

Coats' disease is characterized by abnormal retinal vascular development (so-called 'retinal telangiectasis') which results in massive intraretinal and subretinal lipid accumulation (exudative retinal detachment). The classical form of Coats' disease is almost invariably isolated, unilateral and seen in males. A female with a unilateral variant of Coats' disease gave birth to a son affected by Norrie disease. Both carried a missense mutation within the NDP gene on chromosome Xp11.2. Subsequently analysis of the retinas of nine enucleated eyes from males with Coats' disease demonstrated in one a somatic mutation in the NDP gene which was not present within non-retinal tissue. We suggest that Coats' telangiectasis is secondary to somatic mutation in the NDP gene which results in a deficiency of norrin (the protein product of the NDP gene) within the developing retina. This supports recent observations that the protein is critical for normal retinal vasculogenesis.

Amino Acid Substitution↗