Peripheral hypertrophic subepithelial corneal degeneration: nomenclature, phenotypes, and long-term outcomes.

PURPOSE: To describe the long-term outcomes of peripheral hypertrophic subepithelial corneal degeneration. DESIGN: Retrospective case series. PARTICIPANTS: Twenty-two patients under the care of the External Disease Service, Moorfields Eye Hospital. METHODS: All patients matching clinical diagnostic criteria were included. Symptomatic patients were managed either conservatively or were offered superficial keratectomy in progressive cases where symptom control was inadequate. All excised tissue was examined histologically. MAIN OUTCOME MEASURES: Clinical phenotype, symptoms, recurrence rate after surgery, and histopathologic results. RESULTS: Twenty-two white patients (20 women and 2 men; age range, 27-88 years; median age, 42 years) had peripheral, usually bilateral (20/22 [91%]), elevated circumferential peripheral subepithelial corneal opacities and adjacent abnormal limbal vasculature, with or without pseudopterygia in 9 patients (41%), among whom 7 (32%) patients had bilateral disease. Apart from the abnormal vasculature, there were no signs of chronic ocular surface inflammation. Symptoms were ocular surface discomfort in 10 patients (45%), reduced vision in 4 patients (18%), and both of these in 5 patients (23%). Three patients (14%) were asymptomatic. There was no treatment in 6 patients (27%), topical lubricants in 8 patients (36%), spectacles in 1 patient (5%), and superficial keratectomy in 7 patients (32%; 5 bilateral), which was repeated for incomplete primary excision in 1 eye of 2 patients (9%) and for a bilateral recurrence in 1 patient (5%). Median follow-up after excision was 5 years (range, 1-11 years). Histopathologic changes were similar to those observed in pterygia (vascular component) and Salzmann's nodular degeneration (corneal component). CONCLUSIONS: Peripheral hypertrophic subepithelial corneal degeneration is an uncommon, usually bilateral, idiopathic disorder, occurring mostly in white women with a distinct phenotype. The condition was first described in 2003. Further cases among some patients have been described in more recent case series of Salzmann's nodular degeneration and diffuse keratoconjunctival proliferation, as well as in the previously described familial pterygoid corneal degeneration. Surgical excision was required in 30% of patients in this series, with infrequent short-term recurrences. The cause is uncertain. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

A Comparison of Refractive Accuracy Between Conventional and Femtosecond Laser Cataract Surgery Techniques Using Modern IOL Formulas.

PURPOSE: To compare the refractive outcome prediction accuracy between conventional (CCS) and femtosecond laser assisted (FLACS) cataract surgery techniques using optimized lens constants for modern intraocular lens (IOL) formulas. PATIENTS AND METHODS: Our retrospective, comparative, interventional case series, compared data from 196 eyes undergoing CCS and 456 eyes undergoing FLACS with Acrysof IOL (Alcon laboratories, Inc) implantation. After optimizing IOL constants, the predicted refractive outcome was calculated for all formulas for each case. This was compared to the actual refractive outcome to provide the prediction error. The performance of CCS and FLACS was compared by the absolute prediction error and percentage of eyes within 0.25D, 0.5D and 1.0D of anticipated refractive outcome. RESULTS: There was no statistically significant difference in median absolute error between the CCS and LACS groups for the Kane (0.256, 0.236; p=0.389), SRK T (0.298, 0.302, p=0.910), Holladay (0.312, 0.275; p=0.090), Hoffer Q (0.314, 0.289; p=0.330), Haigis (0.309, 0.258; p=0.177), Barrett Universal 2(0.250, 0.250; p=0.866), Holladay 2 (0.250, 0.258; p=0.860) and Olsen (0.260, 0.255; p=0.570) formulas. Similarly, there was no consistent difference between the two techniques for percentage of patients within 0.25, 0.50 and 1.0D of predicted refractive outcome for each formula. CONCLUSION: There was no difference in refractive outcome prediction accuracy between the CCS and FLACS techniques.

Comparison of the Kane formula with existing formulas for intraocular lens power selection.

OBJECTIVE: To compare the accuracy of a new intraocular lens (IOL) power formula (Kane formula) with existing formulas using IOLMaster, predominantly model 3, biometry (measures variables axial length, keratometry and anterior chamber depth) and optimised lens constants. To compare the accuracy of three new or updated IOL power formulas (Kane, Hill-RBF V.2.0 and Holladay 2 with new axial length adjustment) compared with existing formulas (Olsen, Barrett Universal 2, Haigis, Holladay 1, Hoffer Q, SRK/T). METHODS AND ANALYSIS: A single surgeon retrospective case review was performed from patients having uneventful cataract surgery with Acrysof IQ SN60WF IOL implantation over 11 years in a Melbourne private practice. Using optimised lens constants, the predicted refractive outcome for each formula was calculated for each patient. This was compared with the actual refractive outcome to give the prediction error. Eyes were separated into subgroups based on axial length as follows: short (≤22.0 mm), medium (>22.0 to <26.0 mm) and long (≥26.0 mm). RESULTS: The study included 846 patients. Over the entire axial length range, the Kane formula had the lowest mean absolute prediction error (p<0.001, all formulas). The mean postoperative difference from intended outcome for the Kane formula was -0.14+0.27×1 (95% LCL -1.52+0.93×43; 95% UCL +0.54+1.03×149). The formula demonstrated the lowest absolute error in the medium axial length range (p<0.001). In the short and long axial length groups, no formula demonstrated a significantly lower absolute mean prediction error. CONCLUSION: Using three variables (AL, K, ACD), the Kane formula was a more accurate predictor of actual postoperative refraction than the other formulae under investigation. There were not enough eyes of short or long axial length to adequately power statistical comparisons within axial length subgroups.

Are Duane syndrome and infantile esotropia allelic?

PURPOSE: To evaluate the clinical overlap of families with Duane syndrome and infantile esotropia to determine whether the identification of genes for Duane syndrome may explain some cases of infantile esotropia. METHODS: Three separate groups of patients were evaluated. 1) Families with features of infantile esotropia were identified through the Strabismus Inheritance Study Tasmania (SIST). Clinical details of participants and their families were reviewed for any cases of Duane syndrome. 2) Cases of Duane syndrome were identified through the clinical diagnostic database at the Royal Children's Hospital, Melbourne, and private ophthalmology clinics in Melbourne and Tasmania. Previous medical notes were reviewed and family history of strabismus noted. All affected individuals were invited for re-examination in cases where a positive family history of strabismus was reported; siblings, parents, and other family members, where appropriate, were invited to be examined for signs of Duane syndrome or infantile esotropia. 3) Cases of mosaic trisomy 8, which has been associated with Duane syndrome and infantile esotropia, were reviewed for signs of strabismus. RESULTS: A total of 133 families from the SIST were reviewed, but no 'pure' families of Duane syndrome were identified. Two families with infantile esotropia had several members affected with Duane syndrome. Of the 40 index cases with Duane syndrome whose families agreed to be involved in the study, 21 had a family history of ocular motility disorders, but only two of these families had multiple cases of Duane syndrome. From 24 cases with mosaic trisomy 8, one individual case had Duane syndrome and another had mild congenital cataracts and infantile esotropia. CONCLUSIONS: There is clinical overlap in families with Duane syndrome and infantile esotropia. We confirmed the previous association of mosaic trisomy 8 with both Duane syndrome and infantile esotropia. These data suggest that the two conditions may be allelic and may be due to a gene on chromosome 8.

Contact lens management of keratoconus in a patient with residual astigmatism resulting from implantation of a toric intraocular lens.

Toric intraocular lenses (IOLs) are increasingly being used at the time of cataract surgery to treat regular refractive astigmatism. This paper outlines the contact lens management of a patient with keratoconus, who had marked residual astigmatism post-operatively due to implantation of a toric IOL during cataract surgery. It is strongly recommended that toric IOLs should only be prescribed for patients who have mild forms of keratoconus, with only slight irregular astigmatism that has been stable for at least the previous 12 months and acceptable vision with spectacles.