Noel Alpins A.M

University of Melbourne | MSD · Department Ophthalmology CERA

Purpose To demonstrate how hemidivisional vector planning of refractive laser treatments of astigmatism can be used to directly address idiopathic corneal irregular astigmatism that has an asymmetrical, non-orthogonal bow tie topography appearance. Design Case study. Methods The cornea is conceptually divided into two hemidivisions along the flat...

Purpose: To evaluate how the Total Keratometry astigmatism measure from a swept-source optical biometer compares with simulated keratometry astigmatism from the same device, and total corneal topographic astigmatism (CorT Total) derived from a Scheimpflug tomographer. Methods: For normal virgin eyes, the ocular residual astigmatism (ORA) magnitu...

Ophthalmologists have adopted the ASSORT (Alpins Statistical System for Ophthalmic Refractive surgery Techniques) calculators as their preferred method of astigmatism analyses as demonstrated by their frequency of use and the prevalence of citations in the literature. The calculators’ ability to import unlimited amounts of data and graphically disp...

Jun et al. should be congratulated on their important study comparing clinical outcomes between vector planning (VP) and conventional manifest refraction (MR) for the treatment of myopic astigmatism with small-incision lenticule extraction (SMILE).1,2 The findings of this groundbreaking study demonstrated statistically significant better outcomes f...

Ophthalmologists have adopted the ASSORT (Alpins Statistical System for Ophthalmic Refractive surgery Techniques) calculators as their preferred method of astigmatism analyses as demonstrated by their frequency of use and the prevalence of citations in the literature. The calculators' ability to import unlimited amounts of data and graphically disp...

Purpose: To compare the manufacturer-provided measures of total corneal power (TCP) generated by Scheimpflug and dual Scheimpflug/Placido imaging as compared to corneal topographic astigmatism calculated on the basis of measured TCP data (CorT Total). Setting: Emory University, Atlanta, Georgia, USA. Design: Retrospective case series. Methods...

This ground-breaking study conducted by Dr’s Jun, Kang and colleagues in South Korea is an outstanding example of the use of Vector Planning for correcting astigmatism in SMILE surgery. It is now available for download from the JCRS website for accepted articles “in print”. The paper demonstrates statistically significant better results in Vector...

Purpose: To evaluate how closely manufacturer-provided measures of total corneal astigmatism correspond with the manifest refractive cylinder, as compared to a benchmark of corneal topographic astigmatism calculated on the basis of measured total corneal power (TCP) data (CorT Total). Methods: The SD of the ocular residual astigmatism magnitude...

Purpose: To objectively evaluate the image quality obtained with toric intraocular lenses (IOLs) when misaligned from the intended axis. Setting: University Eye Clinic and the Department of Industrial and Information Engineering, University of Trieste, Trieste, Italy. Design: Experimental study. Methods: An experimental optoelectronic test b...

Misalignment of the surgical treatment is the major source of refractive surprise in relation to astigmatism. Sources of misalignment include cyclotorsion from the seated to supine position, a physical turning of the patients head or intentionally placing a cataract incision on a meridian other than the steepest corneal meridian due to ergonomic fa...

The concept of planning refractive laser treatments using parameters other than manifest or wavefront refraction was somewhat of a novelty until topography-guided treatments came to the forefront more recently. However, both forms of treatment still have their limitations: manifest and wavefront refraction-based treatments do not take into account...

Purpose: To evaluate clinical outcomes of laser in situ keratomileusis (LASIK) with an aberration-neutral profile centered on the estimated visual axis (considering 70% of the pupil offset toward the corneal vertex) comparing vector planning with manifest refraction planning for the treatment of myopic astigmatism. Setting: Muscat Eye Laser Cent...

The surgical correction of astigmatism is the last frontier to optimizing visual outcomes for patients. Practical Astigmatism: Planning and Analysis is a comprehensive guide to correcting astigmatism from preoperative planning to postoperative analysis. This provides readers with unique insight to what actually happened surgically: did the astigmat...

Purpose: To demonstrate how the concept of hemidivisional corneal topographic astigmatism (hemiCorT) enables the planning of hemidivisional corneal treatments to reduce irregularity and overall astigmatism. Methods: Whole-of-cornea corneal topographic astigmatism (CorT) is calculated from topography data derived from a corneal topographer or tom...

Purpose: To demonstrate how to determine the historical coupling adjustments of bitoric mixed astigmatism ablative treatments and how to use these historical coupling adjustments to adjust future bitoric treatments. Methods: The individual coupling adjustments of the myopic and hyperopic cylindrical components of a bitoric treatment were derived...

Noel Alpins1,2 1NewVision Clinics, Melbourne, VIC, Australia; 2Department Ophthalmology, Melbourne University, Melbourne, VIC, Australia It is encouraging to see the results in the article by Kanellopoulos “Topography-modified refraction (TMR): adjustment of treated cylinder amount and axis to the topography versus standard clinical refraction in m...

With so many toric intraocular lens (IOL) calculators available online it is important for the doctor to know what is included to improve the accuracy of the toric IOL recommended. Does it allow for long eyes, short eyes, personalised IOL constants, posterior corneal power, and what are the options available after a refractive surprise? There is mo...

Purpose: To determine whether the flattening effect of corneal incisions differs between the right and left eye. Methods: A retrospective study of preoperative and postoperative corneal astigmatism was performed for patients who had bilateral cataract surgery by a right-handed surgeon. The change in corneal astigmatism was attributed to the 2.2-...

Terminology in the subject of astigmatism is an important aspect of a clear understanding. Employing incorrect terminology in any publication is confusing to readers who want consistency to avoid complicating a subject necessarily The use of source references is also an important component of avoiding conflicting terms.

This case highlights some of the interesting complications resulting from an unrecognised low correlation between corneal and refractive values in a refractive lens exchange. A refractive lens exchange with a toric IOL was called for in this case. Although one would have expected the toric implant to correct for corneal astigmatism, subsequent exci...

Toric IOL calculation involves many variables to achieve an accurate implant power. These are all included in the free Assort online calculator at www.assort.com and include ELP factors Refractive surprise toric calculation requires the same set of contributing factors to determine whether IOL rotation would assist and by how much. Also necessary i...

To evaluate the performance of corneal topographic astigmatism (CorT) based on total corneal power measurements. Anterior, posterior, and total corneal power measurements of 526 virgin eyes obtained using the CSO Sirius tomographer (Costuzione Strumenti Oftalmici, Scandicci, Florence, Italy) were analyzed. Individual CorTs were created from each se...

The fundamental concepts underpinning the vectorial analysis of astigmatism are straightforward and intuitive, easily understood by employing a simple golf-putting analogy. The Alpins methodology utilizes three principal vectors and the various ratios between them to provide an aggregate analysis for astigmatic change with parallel indices for sphe...

To redefine measures of corneal coupling for use with incisional and ablation procedures for astigmatism. Private clinics, Melbourne, Victoria, Australia. Retrospective nonrandomized study. The measures known as the coupling ratio (CR) and coupling constant (CC) were redefined to ensure validity in most cases of incisional procedures and laser visi...

A 44-year-old male chief of police had photorefractive keratectomy (PRK) approximately 1.5 years ago in both eyes; the procedures were performed 1 month apart. The preoperative manifest refraction (MR) was ÿ7.50 diop-ters (D) sphere in the right eye and ÿ6.50 ÿ0.50 Â 105 in the left eye. The preoperative cycloplegic refraction (CR) was ÿ6.75 ÿ0.25...

Techniques are disclosed in which a topographic parameter is determined in each semi-meridian of the eye by considering the topography in each of three concentric zones from the central axis at 3 mm, 5 mm, and 7 mm and assigning weighting factors for each zone, By selectively treating the weighted values in the three zones, parameters of magnitude...

To determine the refractive cylinder effect of rotating a toric intraocular lens (IOL) and identify the sources of refractive astigmatic surprise after toric IOL implantation. Private practice, Melbourne, Australia. Experimental study. Vergence formulas using a standard reduced eye model were used to bring all lens powers to the corneal plane. Doub...

Corneal astigmatism measurement has many modes will variability in quantifying magnitude and meridian. Simulated Keratometry (SimK) which depends on only one ring is unreliable in the presence of any irregularity. The parameter of Corneal Topographic Astigmatism (CorT) is derived from the vectorial mean of many corneal rings and is the most accurat...

To derive a method of quantifying corneal topographic astigmatism (CorT) that accurately represents manifest refractive cylinder. Private practice, Melbourne, Australia. Retrospective study. Axial power measurements obtained using topography in right eyes and left eyes were analyzed. For each Placido ring, an astigmatism value was calculated. The r...

To evaluate outcomes of laser in situ keratomileusis (LASIK) guided by wavefront alone versus wavefront plus topographic data. NewVision Clinics, Cheltenham, Australia. Twenty-one eyes (14 patients) were distributed into 2 groups in a prospective double-masked study. One group was treated by wavefront parameters alone (WF, n = 11), and the other, b...

Although a refractive surprise due to an error in the sphere is quiet uncommon using excimer technology, its clinical impact may be devastating for the patient and the surgeon. There are several sources of mistakes that may cause a refractive surprise: a human source, laser-related condition, laser suite conditions, and the patient’s response to su...

This article discusses the factors that give accuracy in lens implant surgery, which parameters have the greatest influence on outcomes and which formulae are preferred for particularly shaped eyes with their respective refractions

To examine the outcomes of photoastigmatic refractive keratectomy using corneal and refractive parameters for myopia and astigmatism in eyes with forme fruste and mild keratoconus. Private practice, Melbourne, Australia. Photoastigmatic refractive keratectomy was performed with a Star 1 or Star 2 laser (Visx) in 45 eyes with forme fruste or mild ke...

surgery. The patient's ophthalmologist reports unstable keratometry data obtained by corneal topography and the IOL-Master (Carl Zeiss Meditec). Subjective manifest re-fraction is C1.25 À6.50 Â 91 in the right eye and C4.75 À5.25 Â 162 in the left eye with a BCVA of 20/50 and 20/80, respectively. Corneal topography shows corneal astigmatism of À3.4...

Refractive laser surgery techniques such as laser in situ keratomileusis (LASIK) and photore-fractive keratectomy (PRK) are effective methods of treating spherical myopic errors up to 12D and hyperopic errors up to 6D, with good visual out-comes. However, generally more than half of the people who are suitable candidates for refractive sur-gery hav...

Studies of corneal biomechanics show that excessive central flattening can be expected after PRK or LASIK in case of excessive tissue removal. However, this does not explain the difference between the 2 eyes of this patient, nor does it explain the differences in corneal pachymetry. Progressive corneal thinning has been associated with ectasia lead...

The fundamental concepts underpinning the vectorial analysis of astigmatism are straightforward and intuitive, easily understood by employing a simple golf-putting analogy. The Alpins methodology utilizes three principal vectors and the various ratios between them to provide an aggregate analysis for astigmatic change with parallel indices for sphe...

Corneal astigmatism measured by keratometry should be included as a component of "wavefront-guided" excimer laser corneal surgery.

In a recent perspective by Morlet et al 1 there are a number of omissions and fundamental errors of content that lead to erroneous conclusions. These significant inaccuracies overlooked in the review process compromise the article's broad contribution. In Morlet et al 's attempt to detail “the use and limitations of vectors . . . for the analysis...

Comment on Holladay article in JCRS January 2001 Astigmatism Issue, to demonstrate analytical methods for evaluating the results of kerato-refractive surgical procedures and emphasize the importance of intraocular astigmatism. This article along with five other authors' contributions in this Astigmatism Issue, responded to a data set provided by t...

To determine the effectiveness of correcting astigmatism by laser refractive surgery by a vectorial astigmatism outcome analysis that uses 3 fundamental vectors: target induced astigmatism vector (TIA), surgically induced astigmatism vector, and difference vector, as described by the Alpins method. A data set of 100 eyes that had laser in situ kera...

PurposeTo determine the effectiveness of correcting astigmatism by laser refractive surgery by a vectorial astigmatism outcome analysis that uses 3 fundamental vectors: target induced astigmatism vector (TIA®), surgically induced astigmatism vector, and difference vector, as described by the Alpins method.

Using a liberal definition of corneal irregularity, modern videokeratoscopy may define approximately 40% of normal corneas with a toric refractive error as possessing primary irregular astigmatism. The causes of secondary forms of irregular astigmatism include corneal surgery, trauma, dystrophies, and infections. Internal refractive surface and med...

Lasik Lasek and PRK

To define measures of assessing success and subsequent ways to improve excimer laser treatment of astigmatism. We studied 97 eyes of 79 patients, followed for 12 months, that underwent photorefractive keratectomy (PRK) for myopia and astigmatism with a VISX 20/20 excimer laser. Preoperative spherical equivalent refraction at the corneal plane was b...