Refractive Error In Patients Research Articles

Intraoperative cauterization of the cornea can reduce postkeratoplasty refractive error in patients with keratoconus

Objective This study aimed to evaluate the effect of intraoperative corneal cauterization on the postkeratoplasty refraction of patients with keratoconus. Design A randomized clinical trial. Participants Thirty eyes of 29 patients with keratoconus undergoing standard penetrating keratoplasty by the same surgeon were evaluated (MB). Intervention Standard penetrating keratoplasty included the use of an 8.0-mm donor button sutured into a 7.5-mm recipient bed by means of two running 10-0 nylon sutures with 16 bites each. Before trephination of the recipient bed, superficial cauterization causing tissue shrinkage was applied to a 6-mm central area of the cornea of only 15 eyes (group A). The remaining 15 eyes (group B) did not undergo intraoperative cauterization. Before surgery, 6 months, and 13 months after surgery, a complete ophthalmologic examination was performed on each patient, including uncorrected and best-corrected visual acuity, refraction, keratometry, computerized corneal topography, as well as A-scan contact ultrasonography. Main outcome measures Postkeratoplasty refractive error was measured. Results Both 6 months (sutures still in place) and 13 months (suture removal performed in all patients) after surgery, the average spherical equivalent was significantly less myopic in the patients undergoing cauterization. At 6 months, it was +1.72 diopters (D) ± 1.13 D in group A and −3.16 D ± 2.84 D in group B; at 13 months, it was +0.09 D 1.52 D in group A and −3.89 D ± 3.01 D in group B. The average keratometric astigmatism also was significantly lower in group A than in group B both at 6 (2.5 D ± 1.6 D vs. 4.1 D ± 2.3 D) and 13 months (2.7 D ± 1.5 D vs. 4.4 D ± 2.4 D) after surgery. Conclusion Cauterization of the central cornea improves the postkeratoplasty refractive results of patients with keratoconus.

Refractive errors in young children with Down syndrome.

Significant refractive errors are common among older children and adults with Down syndrome. We examined infants and children with Down syndrome to determine the prevalence of these errors at younger ages. Noncycloplegic retinoscopy was used to determine the refractive state of 92 infants and children with Down syndrome, aged 4 months to 12 years. The results for infants show a similar distribution of refractive errors in patients with Down syndrome and an age-matched control group. However, rather than a narrower distribution for the older age groups, as is the case with the controls, the distribution is wider, and the prevalence of refractive errors (including astigmatism) is higher among young children with Down syndrome than among controls. This high prevalence of refractive defects cannot be explained by the presence of strabismus or other pathologies.

Electroretinogram responses and refractive errors in patients with a history of retinopathy prematurity.

Ametropias, particularly myopia, and mild retinal dysfunction are found in eyes with a history of retinopathy of prematurity. The retina is an important controller of refractive development. The aims of this study were to find out whether altered measures of retinal function and ametropias are associated and to consider mechanisms by which the retina might control refractive development. Nine infants and children with a history of stage 1, 2 or 3 retinopathy of prematurity and known courses of refractive development were studied. Spherical equivalents at the time of the electroretinogram ranged from +5.50 to -9.00 diopters. Rod photoresponse characteristics were derived from the a-wave, and postreceptoral components were also analyzed with calculation of the sensitivity and saturated amplitude of the b-wave, the sensitivity of oscillatory wavelet OP2, and average amplitudes of OP3 and OP4. In hyperopic and myopic patients alike, the saturated amplitude and gain of the rod cell response were attenuated. In all patients, b-wave sensitivity was low, but in most there was little effect on saturated b-wave amplitude. In patients with courses toward myopia, the amplitude of OP4, an 'OFF' signal, is relatively more attenuated than that of OP3, an 'ON' signal. OP4 is relatively larger in patients with courses toward hyperopia. The OP results suggest that an imbalance of 'ON' and 'OFF' activity in the retina is associated with development of ametropias in retinopathy of prematurity.

Amblyopia and refractive error in patients who suffered from eyelid haemangioma in early childhood

15 patients with eyelid haemangioma in early childhood had been reevaluated concerning amblyopia and refractive error. There was myopia in 3 of 15 and astigmatism in 9 patients on the tumor side. Amblyopia could be found in all patients with astigmatism higher than 2 diopters, all myopic patients and all patients with localisation of the haemangioma in the lower eyelid. The lower incidence of myopia in our group is discussed In connection with the x-ray therapy which 10 of our patients underwent. It seems necessary in patients with lid haemangioma in early childhood to discover and correct a possible refractive error as soon as possible and in some cases to start orthoptic treatment.

Refractive errors associated with hemangiomas of the eyelids and orbit in infancy

Asymmetrical refractive errors, both astigmatic and myopic, were associated with infantile hemangiomas of the eyelids and orbit in 46% of 37 patients who had large lesions and upper eyelid involvement predisposing to the ammetropia. The axis of the astigmatic error related to the location of the eyelid hemangioma and correlated closely with keratometric measurements of corneal astigmatism. The refractive errors tended to be stable despite eventual resolution of the hemangiomas. Efforts to combat strabismic and refractive amblyopia were rewarding in many patients. A history of complete eyelid occlusion during part of the first year of life was associated with dense amblyopia and eccentric fixation in some patients, but in other patients this history was compatible with the eventual development of useful vision. Absence of an asymmetrical refractive error in patients with eyelid and orbital hemangiomas rendered the prognosis for vision good in involved eyes.

Refractive Errors Associated With Hemangiomas of the Eyelids and Orbit in Infancy

Asymmetrical refractive errors, both astigmatic and myopic, were associated with infantile hemangiomas of the eyelids and orbit in 46% of 37 patients who had large lesions and upper eyelid involvement predisposing to the ammetropia. The axis of the astigmatic error related to the location of the eyelid hemangioma and correlated closely with keratometric measurements of corneal astigmatism. The refractive errors tended to be stable despite eventual resolution of the hemangiomas. Efforts to combat strabismic and refractive amblyopia were rewarding in many patients. A history of complete eyelid occlusion during part of the first year of life was associated with dense amblyopia and eccentric fixation in some patients, but in other patients this history was compatible with the eventual development of useful vision. Absence of an asymmetrical refractive error in patients with eyelid and orbital hemangiomas rendered the prognosis for vision good in involved eyes.

Refractive errors in patients with newly diagnosed diabetes mellitus.

Background and Objective:Diabetes mellitus is a complex metabolic disorder that involves the small blood vessels, often causing widespread damage to tissues, including the eyes’ optic refractive error. In patients with newly diagnosed diabetes mellitus who have unstable blood glucose levels, refraction may be incorrect. We aimed to investigate refraction in patients who were recently diagnosed with diabetes and treated at our centre.Methods:This prospective study was performed from February 2013 to January 2014. Patients were diagnosed with diabetes mellitus using laboratory biochemical tests and clinical examination. Venous fasting plasma glucose (fpg) levels were measured along with refractive errors. Two measurements were taken: initially and after four weeks. The last difference between the initial and end refractive measurements were evaluated.Results:Our patients were 100 males and 30 females who had been newly diagnosed with type II DM. The refractive and fpg levels were measured twice in all patients. The average values of the initial measurements were as follows: fpg level, 415 mg/dl; average refractive value, +2.5 D (Dioptres). The average end of period measurements were fpg, 203 mg/dl; average refractive value, +0.75 D. There is a statistically significant difference between after four weeks measurements with initially measurements of fasting plasma glucose (fpg) levels (p<0.05) and there is a statistically significant relationship between changes in fpg changes with glasses ID (p<0.05) and the disappearance of blurred vision (to be greater than 50% success rate) were statistically significant (p<0.05). Also, were detected upon all these results the absence of any age and sex effects (p>0.05).Conclusions:Refractive error is affected in patients with newly diagnosed diabetes mellitus; therefore, plasma glucose levels should be considered in the selection of glasses.