Mahmoud M Ismail | PubMed Health

PubMed2006

Correction of hyperopia by intracorneal lenses: two-year follow-up.

PURPOSE: To assess the safety and efficacy of intracorneal lenses as a surgical alternative for the correction of hyperopia. SETTING: Al-Azhar University and El Magrabi Eye Hospital, Cairo, Egypt. METHODS: Twenty-three eyes of 21 patients who had a mean hyperopia of 4.3 diopters (D) +/- 0.71 (SD) (range +2.5 to +6.0 D) received Permavision lenses (Anamed Inc.), which are made of a highly permeable hydrogel with a water content of 78% and a refractive index close to that of corneal tissue (1.376). The Moria M2 microkeratome was used to make a 160 microm corneal flap with a diameter of +/-8.5 mm. The intracorneal lens was placed beneath the flap after minimal interface irrigation. RESULTS: Clinical examination showed mild corneal edema and a myopic shift during the first week postoperatively. In 17 eyes (73.9%), the postoperative uncorrected visual acuity was similar to the preoperative best corrected visual acuity (BCVA); 1 eye (4.3%) lost 1 line of preoperative BCVA. In 5 eyes (21.7%), various degrees of lens opacification with some degree of corneal haze were seen after uneventful follow-up. Decentration of 0.5 to 1.0 mm was seen in 2 eyes (8.6%), 1 of which had the lens explanted because of significant opacification. Induced astigmatism was evident in 1 eye (-1.5 D). A total of 16 eyes (69.6%) were within +/-0.5 D of target, and 20 eyes (86.9%) were within +/-1.0 D (87%). No flap melting or extrusion of the lens was recorded in 24 months of follow-up. Night halos and glare were reported in 3 eyes; all had a lens diameter of 5.0 mm. CONCLUSIONS: Intracorneal hydrogel lenses were tolerated relatively well by stromal tissue, providing a reasonably stable and predictable way to correct moderate hyperopia. However, induced astigmatism, stromal opacification, decentration, and night halos and glare occurred in a significant number of eyes. To ensure safety, deep flap cuts are preferred and these eyes should be watched carefully to avoid decentration of the lens in the early postoperative period.

Adult↗

PubMed2002

Correction of hyperopia with intracorneal implants.

PURPOSE: To evaluate the safety and efficacy of intracorneal lenses as a surgical alternative for the correction of hyperopia. SETTING: Al-Azhar University, Cairo, Egypt, and Louisiana State University Eye Center, New Orleans, Louisiana, USA. METHODS: PermaVision lenses (Anamed Inc.) were implanted in the left eye of 20 albino rabbits that were followed for 6 months by confocal microscopy. The lenses are made of a highly permeable hydrogel with 70% water content and a refractive index close to that of corneal tissue (1.376). The Carriazo-Barraquer microkeratome (Moria) was used to create a 150 microm corneal flap with a diameter of 8.5 mm or larger. The intracorneal lens was placed under the flap after minimal interface irrigation. RESULTS: At 3 days, confocal microscopy showed interface edema that resolved after 1 week. No flap melting or excursion of the lens was noted. In 1 eye, a deep lamellar keratitis was seen. At 6 months, the edge of the lens showed excellent compatibility, with no keratocytic activity or intrastromal fibrosis. CONCLUSIONS: Intracorneal hydrogel lenses were well tolerated by stromal tissue in rabbits. They are potentially safe and can be considered as an alternative for the correction of hyperopia. Further clinical studies are required to confirm their safety in humans.

Animals↗