Optometry Research Today is a free monthly online journal that collates and summarizes the latest research about Optometry, including details on myopia, optometric practice, therapy.

A structural investigation of corneal graft failure in suspected recurrent keratoconus.

Hayes S, Young R, Boote C, Hawksworth N, Huang Y, Meek KM

Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.

PurposePenetrating keratoplasty was performed on the right eye of a 51-year-old patient diagnosed with advanced bilateral keratoconus. Thirteen years later, an 8.5 mm regraft was required as a result of gross vascularisation, a poor epithelium, and suspected recurrent keratoconus. To learn more about the structural basis for graft failure, we examined the removed tissue for the presence of abnormalities in the stroma and limiting membranes.MethodsX-ray scattering and electron microscopy were used to study the failed-graft tissue to provide information on the integrity of the limiting membranes and the diameter, dominant orientation, and distribution of collagen within the corneal stroma. The findings were compared with similar structural data from normal and keratoconus corneas.ResultsIn contrast to the keratoconus cornea, a normal orientation and distribution of collagen was seen throughout most of the failed-graft tissue, although abnormalities were observed in the infero-nasal quadrant at the original graft/host junction. The average diameter of collagen fibrils in the failed-graft button did not differ from that of normal corneas.ConclusionsThe structural abnormalities identified in this case of graft failure were not consistent with those typically seen in keratoconus. The clear demarcation of the graft/host boundary 13 years after surgery suggests that a normal stromal collagen arrangement may never be fully achieved in corneal graft wounds.Eye advance online publication, 3 July 2009; doi:10.1038/eye.2009.159.

Published 3 July 2009 in Eye.
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Articles on Optometry published 3 July 2009:

Lifetime costs and effectiveness of ReSTOR compared with a monofocal IOL and Array-SA40 in the Netherlands.   Eye.

PurposeTo estimate the lifetime cost consequences for society and the National Health Service (NHS) of bilateral monofocal (SI40NB) or multifocal (ReSTOR or Array-SA40) intraocular lense (IOL) implantation after cataract surgery.SettingPublic hospital in the Netherlands.MethodsA Markov model simulated three cohorts of patients followed 69 until 100 years of age, or death. Spectacle independence rates for each IOL were adjusted to the results of a randomized clinical trial that compared ... [Abstract] [Full-text]

Corneal Sensitivity and Slit Scanning In Vivo Confocal Microscopy of the Subbasal Nerve Plexus of the Normal Central and Peripheral Human Cornea.   Cornea.

PURPOSE:: To determine the subbasal nerve density and tortuosity at 5 corneal locations and to investigate whether these microstructural observations correlate with corneal sensitivity. METHOD:: Sixty eyes of 60 normal human subjects were recruited into 1 of 3 age groups, group 1: aged <35 years, group 2: aged 35-50 years, and group 3: aged >50 years. All eyes were examined using slit-lamp biomicroscopy, noncontact corneal esthesiometry, and slit scanning in vivo confocal microscopy. ... [Abstract] [Full-text]

Articles on Optometry published 2 July 2009:

Retinal Nerve Fiber Layer Thickness in Normal Hong Kong Chinese Children Measured With Optical Coherence Tomography.   J Glaucoma.

PURPOSE: To obtain the retinal nerve fiber layer (RNFL) thickness normative values of Hong Kong children by using optical coherence tomography (OCT) and to investigate the effect of age and axial length (AL) on RNFL thickness. PATIENTS AND METHODS: One hundred and four normal children aged between 6 and 17 years were recruited for this study. The RNFL thickness was measured by OCT (Stratus OCT). AL was measured by the IOLMaster. RESULTS: The median age of our subjects was 9.75 years (range: ... [Abstract] [Full-text]

Optometrists Association Australia Universal (entry-level) and Therapeutic Competency Standards for Optometry 2008.   Clin Exp Optom, 92(4): 362-5, 366-86.

BACKGROUND: Competency standards for entry-level to the profession of optometry in Australia were first developed in 1993, revised in 1997 and expanded in 2000 to include therapeutic competency standards. The entry-level standards cover the competencies required by a person entering the profession without therapeutic endorsement of their registration. The therapeutic competency standards address the additional competencies required for therapeutic endorsement of registration. This paper ... [Abstract] [Full-text]

Patient and Practitioner Compliance With Silicone Hydrogel and Daily Disposable Lens Replacement in the United States.   Eye Contact Lens.

OBJECTIVE: The objectives of this study were to assess current recommendations for replacement frequency (RF) of silicone hydrogel (SH) and daily disposable (DD) lenses, to determine compliance with these recommendations, and to investigate the reasons given for noncompliance. METHODS: A package containing 20 patient surveys was sent to 309 eye care practitioners (ECPs) in the United States who had agreed to participate in the study. One thousand eight hundred fifty-nine completed surveys were ... [Abstract] [Full-text]

Advances in cataract surgery.   Clin Exp Optom, 92(4): 333-42.

Cataract surgery is a technique described since recorded history, yet it has greatly evolved only in the latter half of the past century. The development of the intraocular lens and phacoemulsification as a technique for cataract removal could be considered as the two most significant strides that have been made in this surgical field. This review takes a comprehensive look at all aspects of cataract surgery, starting from patient selection through the process of consent, anaesthesia, biometry, ... [Abstract] [Full-text]

Clinical assessment of the lower tear meniscus height.   Ophthalmic Physiol Opt.

Purpose: Different values of the lower tear meniscus height (TMH) can be obtained depending on the method and technique of measurement employed. This study aimed to assess (1) differences between the absolute (TMH-A), reflex (TMH-R) and fluorescein (TMH-F) lower tear meniscus heights, (2) differences between the central (TMH-R), nasal (TMH-RN) and temporal (TMH-RT) reflex lower tear meniscus heights and (3) the amount of fluorescein present in the lower tear meniscus, 5 min after fluorescein ... [Abstract] [Full-text]

Articles on Optometry published 30 June 2009:

The effect of head turn on the perception of gaze.   Vision Res, 49(15): 1979-93.

When subjects viewed straight and turned eyes that were isolated singly or in pairs from a head that was straight or turned, they underestimated their true direction of gaze. They also underestimated the direction of head turn when both eyes were closed. However, the judged direction of gaze was improved when the eyes were layered against the heads. Judged direction of averted gaze was primarily based on the abducting eye. The effect that the deviation between an eye's optical axis and its true ... [Abstract] [Full-text]

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