Effect of ageing on keratoconic corneas / Efecto del envejecimiento sobre las córneas con queratocono

Purpose: To explore the potential effect of ageing on the corneal curvature and corrected visual acuity in patients with long-term keratoconus because of the paucity of these patients older than 50 years. Methods: Records of keratoconic patients, who had initially presented to a specialized contact lens clinic and followed for more than 20 years after disease onset, were reviewed. Collected information included age, gender, date of first and last examination, date of onset of the disease, central corneal curvature, refraction, best corrected visual acuity (BCVA), therapeutic modality and clinical signs. Results: Age of patients at last examination was 53.8 years±7.2 (range 44-67 years). Disease onset was self-reported to be at age 18.4 years±3.8. First examination was at age 25.1 years±9.4 and the mean number of years between first and last examination was 28.7 years. Mean central corneal curvature was 6.87mm (48.77D)±0.65 and 6.56mm (51.09D)±0.74, at first and last examination, respectively, a difference which was significant (p<0.001). However, the last measurement of corneal curvature was found to remain approximately constant over the years from about 20 to 50 years after onset. Mean BCVA was not significantly different between first and last examination and was found to be approximately constant over the years. Conclusion: Corneal curvature became steeper possibly within the first 20 years after disease onset but remained approximately unchanged afterwards. Likewise, BCVA remaine (AU)

Objetivo: Explorar el efecto potencial del envejecimiento sobre la curvatura de la córnea y la agudeza visual corregida en pacientes con queratocono a largo plazo, ya que hay una insuficiencia de estos pacientes con edades superiores a 50 años. Métodos: Revisión de las historias de los pacientes con queratocono, que habían acudido inicialmente a una clínica especializada en lentes de contacto, y seguimiento durante más de 20 años desde el inicio de la enfermedad. La información recolectada incluyó edad, sexo, fecha de la primera y la última valoración, fecha de aparición de la enfermedad, curvatura central de la córnea, agudeza visual mejor corregida (BCVA), modalidad terapéutica y signos clínicos. Resultados: La edad de los pacientes en el último examen fue de 53,8 años±7,2 (rango de 44 a 67 años). Los pacientes auto-reportaron el inicio de la enfermedad a los 18,4 años±3,8. El primer examen se realizó a los 25,1 años±9,4, siendo el número medio de años entre el primero y el último examen de 28,7 años. La media de la curvatura central de la córnea fue de 6,87mm (48,77D)±0,65 y 6,56mm (51,09D)±0,74, en el primero y el último examen, respectivamente, una diferencia que resultó significativa (p<0,001). Sin embargo, se comprobó que la última medición de la curvatura de la córnea permanecía más o menos constante durante el transcurso de los años, durante 20 a 50 años desde el inicio. La BCVA media no resultó estadísticamente diferente entre el primero y el último examen, siendo más o menos constante con el paso de los años. Conclusión: La curvatura de la córnea resultó más elevada dentro de los 20 primeros años desde la aparición de la enfermedad, pero no sufrió cambios posteriores. De igual modo, la BCVA permaneció prácticamente constante con el paso de los años, lo que indica una estabilidad relativa de la enfermedad con el transcurso de 20 años (AU)

Effect of ageing on keratoconic corneas.

PURPOSE: To explore the potential effect of ageing on the corneal curvature and corrected visual acuity in patients with long-term keratoconus because of the paucity of these patients older than 50 years. METHODS: Records of keratoconic patients, who had initially presented to a specialized contact lens clinic and followed for more than 20 years after disease onset, were reviewed. Collected information included age, gender, date of first and last examination, date of onset of the disease, central corneal curvature, refraction, best corrected visual acuity (BCVA), therapeutic modality and clinical signs. RESULTS: Age of patients at last examination was 53.8 years±7.2 (range 44-67 years). Disease onset was self-reported to be at age 18.4 years±3.8. First examination was at age 25.1 years±9.4 and the mean number of years between first and last examination was 28.7 years. Mean central corneal curvature was 6.87mm (48.77D)±0.65 and 6.56mm (51.09D)±0.74, at first and last examination, respectively, a difference which was significant (p<0.001). However, the last measurement of corneal curvature was found to remain approximately constant over the years from about 20 to 50 years after onset. Mean BCVA was not significantly different between first and last examination and was found to be approximately constant over the years. CONCLUSION: Corneal curvature became steeper possibly within the first 20 years after disease onset but remained approximately unchanged afterwards. Likewise, BCVA remained practically constant over the years indicating relative stability of the disease after 20 years.

Scleral contact lenses for visual rehabilitation after penetrating keratoplasty: long term outcomes.

PURPOSE: To evaluate the success rate of highly gas permeable scleral contact lenses (SCL) for visual rehabilitation after penetrating keratoplasty (PK), over a period of up to 9 years. METHODS: A total database of 31 consecutive patient fitted with SCL between January 2004 and December 2009 was retrospectively reviewed. Demographic data, etiology prior to lens fitting, visual outcomes, follow up time and complications were analyzed. RESULTS: All eyes were fitted due to inadequate spectacle-corrected vision after successful penetrating keratoplasty or failure of other contact lens modalities. Out of 31 patients fitted, 28 (33 eyes) continue to wear SCL for periods between 0.5 and 8.8 years. The mean duration of follow-up after contact lens fitting was 5.2 ± 2.2 years. The mean age of corneal graft was 17.6 ± 11.4 years (range 4.3-42), and the mean interval between PK and initial contact lens fitting was 12.2 ± 10.7 years (range 0.7-36.0). The average steepest keratometry of our cohort was 55.0 ± 7.5 diopter (D) and the refractive astigmatism was 8.0 ± 4.4 D. The mean contact lens corrected visual acuity (BCVAcl) was 0.78 ± 0.25 (range 0.3-1.2). Twenty-three (82%) patients achieved a functional vision of 0.5 or more. During the studied period, ten (30.0%) eyes presented at least one graft rejection episode and two eyes (6%) had an episode of microbial keratitis. Corneal transplants of 20 years or more show a higher rate of refits due to ectasia recurrence. CONCLUSIONS: Scleral lenses should be considered as lens of choice in eyes with complex corneal geometry, as besides visual rehabilitation, their use may delay or prevent further surgical involvement.

Wearing time as a measure of success of scleral lenses for patients with irregular astigmatism.

OBJECTIVES: To evaluate the visual correction and clinical performance with scleral contact lenses (CL) for the visual rehabilitation of irregular astigmatism and to report the effect of brief wearing breaks on the wearing time and success rate. METHODS: A retrospective review was performed on consecutive patients who were fitted with scleral CL because of irregular astigmatism following failure of other optical corrections. Visual acuity (VA) and wearing times were abstracted. RESULTS: The 97 consecutive identified patients (155 eyes) were divided according to the diagnosis: (1) keratoconus (105 eyes; 67.7%), (2) postpenetrating keratoplasty (PK) (28 eyes; 18.1%); (3) multiple diagnoses (22 eyes; 14.2%)-postradial keratotomy, keratoglobus, pellucid marginal degeneration, PK with aphakia, and iatrogenic ectasia. The mean follow-up was 34.9 ± 18.5 months (range, 2-71 months). There was a significant increase in best VA-scleral when compared with the previous best VA-prescleral (P<0.001). The best VA-scleral was similar in the 3 groups (P>0.5). Patients who took brief breaks every 4 to 5 continuous wearing hours had a significantly higher success rate (P<0.001) among all diagnosis groups. The success rate in wearing time in the keratoconus group was significantly higher than in the PK group (P<0.001). Twenty-six patients (27%) discontinued to wear scleral lenses. CONCLUSION: Scleral lenses can be used successfully for visual rehabilitation and management of irregular astigmatism from various causative factors. The daily wearing time was significantly improved by taking brief breaks for replenishing the CL.

Characteristics of 244 patients with keratoconus seen in an optometric contact lens practice.

BACKGROUND: The purpose of this study was to describe the characteristics of keratoconic patients seen in a specialised contact lens practice from a general population with a high prevalence of the disease. METHODS: Patients attending a contact lens practice for management of keratoconus were asked to complete a questionnaire. Data were collected on demographic characteristics, general health, family history, eye rubbing, allergy, asthma, eczema, education level, history of keratoplasty and smoking. RESULTS: Two hundred and forty-four patients completed the questionnaire. There was a male bias (54.5 per cent). The majority of the patients (78.7 per cent) wore contact lenses, of whom 67.7 per cent wore hard, 13 per cent soft and 4.2 per cent scleral contact lenses. Some of the patients (21.3 per cent) had undergone corneal graft surgery. Eighteen per cent had an associated systemic disease, the most common of which was type 2 diabetes, although this disease was less prevalent, but not significantly, in the keratoconic sample than in the general population (p = 0.19). The prevalence of eye rubbing (65.6 per cent) was similar to other studies. Compared to the general population, asthma (13.2 per cent) was slightly, but not significantly, less prevalent (p = 0.17), eczema (6.6 per cent) was significantly less (p < 0.001) and allergy (34.4 per cent) was more prevalent (p < 0.001). A high proportion of patients reported a family history of the disease (27.9 per cent) and most were better educated than the general population. CONCLUSION: The results of this survey concur with those of other studies with regard to most known characteristics of keratoconus; however, the proportion of asthma and eczema tended to be less than in other surveys and may be linked to the environmental influence of a hot and sunny country. The high prevalence of positive family history of the disease in this cohort suggests a genetic influence.

Scleral contact lenses may help where other modalities fail.

PURPOSE: To describe the vision-correcting and therapeutic benefits of gas-permeable scleral contact lenses (GP-ScCL) in the management of irregular corneal surface disorders and ocular surface diseases. METHODS: The charts of 48 consecutive patients (66 eyes) whose management included the use of GP-ScCL were reviewed. RESULTS: The most common indication for fitting the lenses was keratoconus in patients who had to stop wearing other types of corneal lenses (44 eyes, 74.6%). Other indications included extreme corneal irregularity after penetrating keratoplasty, nonhealing corneal ulcer, postoperative dry eye syndrome following laser in situ keratomileusis (LASIK), severe exposure keratitis and acid burn. Mean follow-up was 17 months (range, 2-96). Mean wearing time of the GP-ScCL was 16.2 hours per day (range, 3-18). Visual acuity of 20/40 or better was achieved in 90.9% of keratoconus patients and in 81.8% of postkeratoplasty patients. A gain of two or more Snellen lines was observed in 94.5% of eyes treated for improving vision. Marked subjective improvement in quality of life was reported by 86% of the patients, mainly as a result of improvement in their visual function and reduction in discomfort. Five patients (seven eyes) failed to wear GP-ScCL. CONCLUSION: GP-ScCL can provide successful and safe visual and therapeutic solutions for ocular conditions when conventional contact lenses and medical treatment have failed and where surgery is undesirable or contraindicated.