[Assessment of hoffer correction factor for biometry in eyes with phakic intraocular lens implants]

To assess Hoffer correction factor in measurement of axial length [AL] in eyes with phakic IOL implants. In this descriptive historical cohort study, axial length was measured by ultrasound [US] and IOL Master in both phakic and pseudophakic modes in 24 eyes of 14 patients with Artisan intraocular lenses [IOLs] implanted for refractive purposes, Hoffer's suggested formula for correcting ultrasound AL was applied to the data [cor-US] and all four datasets were compared to preoperative ultrasound AL values as standards. The mean difference between preoperative ultrasound measurements and postoperative readings by US [ALpo], IOL Master in phakic mode [AL IOL Mp], IOL Master in pesudophakic mode [AL IOL Mpp] and US corrected with Hoffer factor [ALhc], were 0.01, 0.022, 0.13, and 0.61mm, with mean absolute differences of 0.23, 0.23, 0.26, and 0.25mm, respectively. In these readings, respectively 42.3%, 37.5%, 57.50%, and 46.2% of differences were greater than 0.2 mm, which is considered to be clinically important. Use of the Hoffer correction factor has no clinical application for a more accurate biometry in patients with an Artisan implant. The most reliable method in this type of patients is making an accurate record of their preoperative AL measured with ultrasound or IOL Master

Molecular investigation of Leber's hereditary optic neuropathy common mutation in suspected patients

LHON is a mitochondrial neurodegenerative disorder often manifesting itself in the second or third decade of life, and hence resulting in progressive central vision loss sually in a short period of 2-8 weeks within which different degrees of blindness may occur. Etiologically, more than twenty missense mutations have been reported for LHON, amongst which the three mutations of G11778A, G3460A and T14484C, affecting NADH dehydrogenase complex activity, are recognized as primary mutations. The three primary mutations account for 90% of LHON patients, emphasizing the importance of molecular investigation of these mutations for differential diagnosis of LHON. Using PCR-RFLP, this research resulted in the detection of two LHON families carrying the G11778A mutation in homoplasmy and described the clinical and molecular features of the disease in the patients