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PubMed2006

Toric phakic intraocular lens for the correction of hyperopia and astigmatism.

PURPOSE: To evaluate the Artisan toric phakic intraocular lens (pIOL) for the correction of hyperopia and astigmatism. SETTING: Department of Ophthalmology, Erasmus MC, Rotterdam, The Netherlands, and Department of Ophthalmology, Sint Truiden, Belgium. METHODS: In this prospective study of 47 eyes of 28 patients with hyperopia and astigmatism, Artisan toric pIOLs were implanted between April 1999 and June 2004. Uncorrected visual acuity (UCVA), best corrected visual acuity, refraction, astigmatism, safety, and predictability were analyzed. Change in astigmatism was analyzed with vector analysis. Refractive cylinders are expressed in minus form. RESULTS: Mean preoperative spherical equivalent was +4.33 diopters (D) +/- 2.26 (SD). Mean follow-up was 11.1 months (range 6 to 36 months). A gain of 1 or more lines in best spectacle-corrected visual acuity (BSCVA) was seen in 36.2%. Safety index and efficacy index after 6 months were 1.06 and 0.87, respectively. The mean postoperative astigmatism at 6 months was 0.19 D at an axis of 144 degrees. At 6 months, about three quarters (76.6%) of the eyes had a UCVA of 20/40 or better. One eye lost 2 lines of BSCVA. In 1 eye, the lens position had to be changed because of a large axis misalignment. No serious complications developed in any of the treated eyes during follow-up. CONCLUSIONS: Artisan toric pIOLs can correct moderate to high hyperopia combined with astigmatism with good refractive results. In this study, there were no serious complications. However, the predictability of the refractive results appeared to be lower than those in the correction of myopia and astigmatism with toric Artisan lenses.

Adult↗

PubMed2006

Conductive keratoplasty to correct residual hyperopia after cataract surgery.

PURPOSE: To evaluate the efficacy, predictability, safety, and stability of conductive keratoplasty (CK) for correcting residual hyperopia after cataract surgery with intraocular lens implantation. SETTING: Vissum-Instituto Oftalmologico de Alicante, Alicante, and Vissum-Instituto de Albacete, Albacete, Spain. METHODS: Sixteen eyes of 16 patients had CK for the correction of residual hyperopia after cataract surgery. The CK was performed with the CK View Point Refractec (RCS-200, Refractec, Inc.). The follow-up was 12 months. RESULTS: One year after CK, 10 eyes (62.5%) achieved an uncorrected visual acuity (UCVA) of 0.50 or better. The mean UCVA was 0.50 +/- 0.21 (SD), and the mean best spectacle-corrected visual acuity (BSCVA) was 0.68 +/- 0.24. One eye lost 1 line of BSCVA, and none lost 2 or more lines. The mean spherical equivalent refraction was +0.39 +/- 0.84 D 1 year after CK. No vision-threatening complications occurred. CONCLUSIONS: One-year data show that CK for the correction of low to moderate hyperopia after cataract surgery was safe, stable, relatively predictable, and efficient. No complications occurred when CK was performed after phacoemulsification.

Aged↗

PubMed2005

5-year follow-up of LASIK for hyperopia.

PURPOSE: To assess the long-term efficacy and stability of LASIK for hyperopia (+0.75 to +7.00 diopters [D]). DESIGN: Retrospective follow-up study of a previous phase III multicenter clinical trial (unpublished data). PARTICIPANTS: Patients who had been treated for hyperopia (33 individuals, 47 eyes) attended follow-up 5 years after surgery. The preoperative mean spherical equivalent at the spectacle plane was +3.58 D (range, +0.75 to 7.00 D), and the attempted mean spherical correction at the corneal plane was +3.18 D (range, +1.00 to +6.00 D). INTERVENTION: Treatments were performed using a Moria LSK One microkeratome and a Summit Technology SVS Apex Plus excimer laser fitted with an Axicon. MAIN OUTCOME MEASURES: Manifest refraction, uncorrected visual acuity, best spectacle-corrected visual acuity, corneal transparency, complications, and patient satisfaction were recorded. RESULTS: At 5 years, for treatments between +1.00 to +3.00 D, 71.0% of eyes were within +/-1.00 D of the intended correction, and for treatments between +3.5 to +6.0 D, 37.5% of eyes were within +/-1.00 D of intended correction. From 12 to 54 months after surgery for all patients, there was a hyperopic shift of +0.53 D (range, -0.13 to +3.13 D), with 51.1% of eyes experiencing an increase of +0.50 D or more and 27.7% of eyes showing a hyperopic shift of more than +1.00 D. This hyperopic shift was +0.67 D (range, 0 to +1.125 D) for patients younger than 40 years of age and +0.44 D (range, -1.33 to +1.50 D) for patients between 43 and 55 years of age. CONCLUSIONS: LASIK was moderately effective for the correction of low degrees of hyperopia. However, there was regression throughout the 5-year follow-up that was greater than would be expected as a result of aging. Long-term stability of hyperopic LASIK refractive corrections, therefore, is uncertain.

Adult↗

PubMed2003

Two-year follow-up of noncontact holmium laser thermokeratoplasty for the correction of low hyperopia.

PURPOSE: To summarize the 2-year results of laser thermal keratoplasty with a holmium:yttrium-aluminum-garnet (Ho:YAG) laser and the Sunrise Corneal Shaping System and assess the procedure's safety, efficacy and predictability in correcting hyperopia in a phase III clinical intervention case series. METHODS: The Ho:YAG laser was used to correct low hyperopia (manifest spherical equivalent of +0.75 to +2.50 dioptres [D], with manifest cylinder of 1.00 D or less) in 38 eyes of 28 patients 40 years of age or older. Laser pulses were delivered to the cornea in 2 radially placed, concentric, 8-spot rings 6.0 and 7.0 mm in diameter. The last follow-up was at 2 years. RESULTS: The preoperative uncorrected visual acuity (UCVA) at distance was less than 20/40 in 82% of the eyes and at near was less than 20/32 in 42%. At 2 years the distance UCVA was 20/40 or better in 100% of the eyes and 20/20 or better in 84%, and the near UCVA was 20/32 or better in 97% of the eyes and 20/20 or better in 8%. The difference between the preoperative and postoperative UCVA was statistically significant (p < 0.01). The correction at 2 years was within 0.50 D of that intended in 92% of the eyes and within 1.00 D in 100%. The reduction in mean spherical equivalent at 2 years was statistically significant (p < 0.0001). No loss of 2 lines or more in best-corrected visual acuity occurred after the 1st month of follow-up. INTERPRETATION: The Ho:YAG Sunrise Corneal Shaping System is safe and effective for the treatment of low hyperopia and astigmatism. It provides a predictable refractive outcome at 2 years of follow-up. However, our results show a tendency towards regression by 2 years.

Adult↗

PubMed2002

Hyperopic laser-assisted in situ keratomileusis for radial keratotomy induced hyperopia.

PURPOSE: To evaluate hyperopic laser in situ keratomileusis (H-LASIK) for radial keratotomy (RK)-induced hyperopia. DESIGN: Noncomparative interventional retrospective nonconsecutive case series. PARTICIPANTS: Sixty-nine eyes of 47 patients who had undergone RK and were seen with induced hyperopia. METHODS: H-LASIK was performed with an excimer laser. MAIN OUTCOME MEASURES: The mean refractive error, in spherical equivalents (SE), uncorrected visual acuity (UCVA), and best spectacle-corrected visual acuity (BSCVA) before and after H-LASIK are reported. Safety was analyzed using a mean follow-up time of 6.6 plus minus 3.24 months. RESULTS: Preoperative mean SE was +3.4 plus minus 1.6 diopters (D). Postoperative mean SE was -0.32 plus minus 1.2 D. A high percentage of eyes (79.7%; n = 55) were between plus minus1.0 D of emmetropia and 88% within plus minus 2.0 D. Preoperative BSCVA was 20/20 in 53.6% of eyes (n = 37) and 20/40 or better in 100% (n = 69). Postoperative BSCVA was 20/20 in 55% of eyes (n = 38) and 20/40 or better in 95.6% (n = 66) of eyes. Preoperative UCVA was less-than-or-equal20/50 in 52 cases (75.4%). Postoperative UCVA was 20/20 in 13 cases (18.8%) and greater-than-or-equal20/40 in 45 cases (65.2%). Four eyes lost 2 Snellen lines because of epithelial ingrowth in the interface (n = 3) and diffuse lamellar keratitis (Sands of the Sahara syndrome; n = 2). One of the eyes with Sahara syndrome also had epithelial ingrowth and flap necrosis. Thirteen eyes lost 1 Snellen line, and 50 eyes maintained or gained Snellen lines. The only intraoperative complication was incision opening (n = 8) while the flap was lifted; there were no further complications. These patients did not lose any Snellen lines of their BSCVA. CONCLUSIONS: H-LASIK can be used successfully to correct RK-induced hyperopia.

Adult↗

PubMed2002

Conductive keratoplasty for the correction of low to moderate hyperopia: 1-year results on the first 54 eyes.

OBJECTIVE: To document the 1-year postoperative clinical results of the safety, efficacy, and stability of conductive keratoplasty (CK) to correct low to moderate hyperopia. DESIGN: Prospective, nonrandomized, self-controlled trial. PARTICIPANTS: Five surgeons at four centers performed CK on the first 54 eyes of a multicenter, 2-year clinical trial. Treated eyes had +0.875 to +4.00 diopters (D) of hyperopia and < or =0.75 D of cylinder. The nature of this procedure was explained to all participating patients who signed informed consent forms prior to undergoing the procedure. INTERVENTION: Low energy, high-frequency current was applied directly into the peripheral corneal stroma through a delivery tip inserted at 16 or more treatment spots. An early nomogram was used for the first 54 eyes with an intended refraction of plano. MAIN OUTCOME MEASURES: Data from all 54 eyes were analyzed for safety and stability. A subset of 30 of the 54 eyes was found that had been treated with the appropriate number of spots with the early nomogram. These eyes were categorized as current nomogram eyes; the data for these eyes were analyzed for efficacy and predictability, as well as stability and safety. All patients reported on satisfaction and quality of vision after surgery. RESULTS: Preoperatively, the manifest refractive spherical equivalent refraction (MRSE) of the 30 current nomogram eyes was +1.57 D. At 1 year postoperatively, uncorrected visual acuity was 20/20 or better in 57% of the eyes and 20/40 or better in 93%. The MRSE was within 0.50 D in 46%, within +/-1.00 D in 93%, and within +/-2.00 D in 100%. No eye lost > or =2 lines of best spectacle-corrected visual acuity at 1 year postoperatively nor had an induced cylinder of > or =2.00 D. The MRSE changed a mean of 0.25 D +/- 0.43 between 3 and 6 postoperative months, 0.16 D +/- 0.38 between 6 and 9 postoperative months, and 0.07 D +/- 0.38 between 9 and 12 postoperative months. Refractive stability appeared to be attained by 6 months postoperatively. CONCLUSIONS: Conductive keratoplasty appears to be safe, effective, and stable for correcting low to moderate spherical hyperopia. Stability appeared by the 6-month follow-up visit. For the eyes treated with the current CK nomogram, uncorrected visual acuity, predictability, and stability are as good as or better than those obtained with hyperopic laser in situ keratomileusis or noncontact laser thermal keratoplasty.

Adult↗

PubMed1997

Excimer laser photorefractive keratectomy for the correction of hyperopia using an erodible mask and axicon system.

PURPOSE: The purpose of the study is to evaluate photorefractive keratectomy for the correction of hyperopia using the erodible mask and Axicon system. METHODS: Forty-three patients (43 eyes) with a mean refraction (spherical equivalent) of +4.54 diopter (D) (range, +1.75 to +7.50 D) were treated using a Summit Technology "Apex Plus" excimer laser. This system uses an erodible mask to create a 6.50-mm diameter hyperopic correction over the axial cornea. An Axicon then is used to fashion a 1.50-mm "blend zone" around the correction. On the basis of preoperative refractions, patients were assigned to 3 groups: 2 groups of 14 patients underwent either "+2.00 D" or "+3.00 D" corrections and 15 patients had "+4.00 D" corrections. RESULTS: All patients had a reduction in their hyperopia with an overcorrection, especially in the first month after surgery and some stability in the refractive change at 3 to 6 months. The mean manifest refraction (n = 43) at 6 months was -0.17 D (range, +4.50 D to -3.125 D). Patient satisfaction was high. At 6 months, all eyes had an improvement in unaided near visual acuity. Unaided distance acuity was improved in 37 eyes (86%). A ring of haze 6.5 mm in diameter appeared in all eyes 1 month after surgery. Night halo measurements at 6 months showed no differences from preoperative levels. Flicker contrast sensitivity and forward light scatter (glare) measurements showed no differences after surgery. CONCLUSIONS: In this short-term study, photorefractive keratectomy for hyperopia using the erodible mask and Axicon system appeared to be a promising procedure. Visual performance, in terms of flicker contrast sensitivity, forward light scatter, and night halos, was not compromised. There was an overcorrection based on the manufacturer's algorithms. Manipulation of the treatment algorithms should improve future predictability.

Adult↗

PubMed1997

Photorefractive keratectomy for hyperopia: six months results in 45 eyes.

OBJECTIVE: To evaluate the safety and efficacy of photorefractive and photoastigmatic keratectomy for hyperopia. METHODS: The Chiron Keracor 116 excimer laser (Chiron Technolas, Munich, Germany) was used to create a peripheral annular ablation profile for the correction of hyperopia and a prior cylindrical ablation in the negative axis for correction of the astigmatic component in 45 consecutive eyes with up to +6.50 diopters (D). All patients were followed for a minimum of 6 months. RESULTS: At 6 months, mean subjective refraction was +0.12 D (standard deviation, 0.70), with 87% within 1 D of emmetropia. Ninety-three percent achieved uncorrected visual acuity of 20/40 or better. Three eyes (6.7%) lost 2 lines of best spectacle-corrected visual acuity and six eyes (13.3%) gained 2 lines or more. CONCLUSIONS: Photorefractive and photoastigmatic keratectomy effectively and predictably reduced hyperopia, improving uncorrected visual acuity in all patients at 6 months. Longer follow-up is required to be certain that refractive changes are stable.

Astigmatism↗

PubMed1998

Laser vision correction for low hyperopia. An 18-month assessment of safety and efficacy.

OBJECTIVE: This study aimed to assess the efficacy and safety of hyperopic photorefractive keratectomy (PRK) and to evaluate the effect of degree of hyperopia, two epithelial removal methods, and various postoperative patient management techniques on clinical outcomes. DESIGN: Prospective, nonrandomized, open-label clinical trial. PARTICIPANTS: A total of 38 patients with mean follow-up of 13.9 months (n = 65 eyes with hyperopia from +1.00 diopter [D] to +4.00 D) participated. INTERVENTION: Hyperopic PRK with the VISX STAR Excimer Laser System was performed. MAIN OUTCOME MEASURES: Spherical equivalent (SE) including vector analysis of SE; uncorrected visual acuity (UCVA); best-spectacle corrected visual acuity (BSCVA); low-, medium- and high-contrast visual acuities; topography; keratometry; pachymetry; and intraocular pressure, haze, and all other potential complications were measured. RESULTS: A total of 80% of eyes were within +/- 0.5 D and all but 1 eye (98%) were within +/- 1.0 D of intended manifest SE at 1 year. There was no induced astigmatism at 1 year. At 12 months, 72% of eyes had UCVA of 20/25 or better and 70% had achieved preoperative BSCVA, with no eye seeing worse than 20/25. These results remained constant at 18 months. There was a tendency toward regression between months 1 and 6 with stabilization of SEs between months 6 and 12. Thereafter, up to 18 months, there was some regression with a mean of +0.31 D, but the number of patients was small. There was one mild decentration and very slight decreases in mean intraocular pressure and central corneal thickness. One patient had grade 1.0 haze develop in both eyes at 12 and 18 months; all other patients experienced trace or no haze. There were no significant complications. CONCLUSIONS: The results of this study support the hypothesis that laser vision correction is safe and effective for treating low hyperopia. The predictability of the hyperopic laser vision correction procedure used in this study was very good. Other than the slower recovery of BSCVA and UCVA seen with this procedure, as compared with myopic PRK, there were no significant complications. The trend toward some later regression needs to be further evaluated in a larger number of patients. Overall, patients were very pleased with the treatment, even in the first 6 months.

Adult↗

PubMed2002

Laser in situ keratomileusis enhancement for consecutive hyperopia after myopic overcorrection.

PURPOSE: To assess the efficacy, predictability, and safety of laser in situ keratomileusis (LASIK) for the treatment of consecutive hyperopia after myopic LASIK. SETTING: Stanford University School of Medicine, Stanford, California, USA. METHODS: In a retrospective study, 36 eyes of 30 patients with consecutive hyperopia after myopic LASIK had LASIK retreatment using the VISX S2 excimer laser. Primary outcome variables including uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, complications, and vector analysis were evaluated preoperatively and 1 day and 3 months postoperatively. RESULTS: The mean spherical equivalent decreased from +1.52 diopters (D) +/- 0.55 (SD) (range +0.63 to +2.63 D) preoperatively to -0.10 +/- 0.52 D (range -1.25 to +1.50 D) 3 months after retreatment. The UCVA was 20/20 or better in 24 eyes (66.7%) and 20/40 or better in 34 eyes (94.4%). Twenty eyes (55.5%) were within +/-0.5 D of the intended correction and 34 eyes (94.4%), within +/-1.0 D. No eye lost 2 or more lines of BSCVA. One eye (2.8%) developed diffuse lamellar keratitis that resolved without sequelae, and 2 eyes (5.6%) developed nonprogressive epithelial ingrowth that did not require removal. CONCLUSIONS: Laser in situ keratomileusis retreatment for consecutive hyperopia following myopic LASIK was an effective, predictable, and safe procedure. Long-term follow-up is needed to assess stability.

Adult↗

PubMed1988

Hexagonal keratotomy for correction of low hyperopia: preliminary results of a prospective study.

Fifteen sighted eyes of 11 patients had hexagonal keratotomy for the correction of low hyperopia. Mean preoperative hyperopia of +3.21 diopters (range +1.75 to +5.50) was reduced a mean of 2.16 diopters (range 0 to -3.25) and keratometry was increased a mean of +2.22 diopters (range +0.75 to +3.71). Follow-up averaged 9.5 months (range 2.0 to 17.5). Ten of the 15 eyes (67%) had at least six months follow-up. No eye had better than 20/80 uncorrected visual acuity preoperatively. Fourteen eyes (93%) had 20/80 or better uncorrected acuity at the most recent postoperative visit. Nine of the 15 eyes (60%) had uncorrected acuity of 20/40 or better. Refractive spherical equivalent appeared to stabilize by three months for most patients. Astigmatism was increased a mean of only +0.02 diopter and no serious complications occurred. Further follow-up is required to assess the safety and efficacy of hexagonal keratotomy for reducing low levels of hyperopia.

Astigmatism↗

PubMed1997

Excimer laser photorefractive keratectomy for low hyperopia: safety and efficacy.

PURPOSE: To assess the safety and efficacy of photorefractive keratectomy (PRK) to correct low hyperopia. SETTING: University of Ottawa Eye Institute, Ottawa General Hospital, Ontario, Canada. METHODS: Twenty-five eyes with refractions of +1.00 to +4.00 diopters (D) and cylinder of 1.00 D or less were treated for hyperopia with the VISX Star excimer laser system using a refined ablation architecture. Thorough visual assessments were performed preoperatively (baseline) and 1, 3, and 6 months postoperatively. Complications were recorded and the level of patient satisfaction was noted. RESULTS: Mean spherical equivalent at 6 months was +0.27 D +/- 0.55 (SD), which was an 89% reduction over baseline. Eighty-four percent of patients gained two to seven lines of near uncorrected visual acuity (UCVA) and 1 patient (4%) lost more than one line. Eight percent achieved 20/25 or better UCVA. Approximately half realized their preoperative distance best corrected visual acuity (BCVA) by 1 month. By the end of the study, all patients had improved, achieved, or were within one line of their baseline distance BCVA. There were some slight reductions in lower contrast acuity at 6 months, although dim lighting conditions did not further reduce these acuities. Most patients had no clinically meaningful change in cylinder. The most common complications included early, transient corneal surface irregularities and visual symptoms and trace haze (grade < or = 0.5) in 14 of 23 patients at 6 months. All but 1 patient expressed a high degree of satisfaction. CONCLUSIONS: These results support the hypothesis that PRK shows great promise as a safe and effective treatment for low hyperopia. There were no significant complications and no decentered ablations. The slight regression occurred with or without the presence of trace haze. Overall, refractive stability was encouraging, although longer follow-up is needed.

Adult↗

PubMed1998

Noncontact thermokeratoplasty to correct hyperopia induced by laser in situ keratomileusis.

PURPOSE: To evaluate the efficacy and safety of noncontact holmium:YAG (Ho:YAG) laser thermokeratoplasty (LTK) for treating hyperopia induced by laser in situ keratomileusis (LASIK). SETTING: Department of Ophthalmology, University of Alicante, Instituto Oftalmológico de Alicante, Alicante, Spain, and the University of Al-Azhar, Cairo, Egypt. METHODS: Noncontact LTK was applied to 13 eyes (11 patients) with significant hyperopia after LASIK using a Ho:YAG laser (model gLase 210, Sunrise Technologies). Mean spherical equivalent before LTK was +4.60 diopters (D) +/- 1.40 (SD) (range +2.50 to +7.25 D). The results were evaluated 18 months after the LTK surgery. RESULTS: A significant myopic shift developed in all eyes that gradually receded to emmetropia 6 to 8 weeks after LTK. After 12 months, refraction was relatively stable. At 18 months, there was a statistically significant difference between the mean uncorrected visual acuity (UCVA) before LTK (0.19 +/- 0.09) and mean postoperative UCVA (0.61 +/- 0.22) (P < .005). At the end of the study, there was a mean increase of 4.10 +/- 1.12 D in central keratometric power. Total regression did not occur in any eye. CONCLUSION: Noncontact Ho:YAG LTK was safe and effective in correcting LASIK-induced hyperopia. The cutting of Bowman's layer and a thinner corneal center may contribute to the stability of LTK in such cases.

Adult↗

PubMed1998

Laser in situ keratomileusis for hyperopia.

PURPOSE: To examine the initial results of laser in situ keratomileusis (LASIK) for hyperopia. SETTING: Arzt für Augenheilkunde, Mannheim, and Photoingenieur, Wendelstein, Germany. METHODS: This retrospective study evaluated 43 eyes having hyperopic LASIK using the Automatic Corneal Shaper (Chiron Vision) and the MEL 60 excimer laser (model 94, Aesculap-Meditec). Patients were divided into two groups. Group 1 consisted of 20 eyes with a refraction from +1.00 to +4.00 diopters (D) and Group 2, 23 eyes from +4.25 to +8.00 D. Objective refraction and visual acuity were measured over 12 months. RESULTS: One year after LASIK, Group 1 had a mean spherical equivalent of +0.33 D (range -0.79 to +1.45 D) and Group 2, +1.91 D (range -0.08 to +3.71 D). Best corrected visual acuity remained unchanged in 35.0% in Group 1 and 56.5% in Group 2. Five percent in Group 1 and 7.3% in Group 2 lost more than 2 lines of best corrected visual acuity. CONCLUSIONS: Laser in situ keratomileusis for hyperopia resulted in less regression, minimal haze, and better predictability and stability than surface photorefractive keratectomy. Preoperative corneal radius appeared to be an important factor in eyes with high hyperopia.

Adolescent↗

PubMed1998

Abnormal head posture associated with high hyperopia.

BACKGROUND: An abnormal head posture may be adopted for ocular or nonocular reasons. The most common ocular reasons are to maintain binocularity and to obtain the best possible visual acuity. Patients with undercorrected or overcorrected refractive errors have been reported to adopt a variety of head positions, thought to be an attempt to obtain the best possible visual acuity. METHODS: Five patients with symmetric high hyperopia (at least + 5.00 D) and an abnormal head posture are presented. RESULTS: All five patients demonstrated an abnormal head posture of chin down for fixation without the spectacle correction in place. This abnormal head posture was eliminated by occlusion of either eye and also by wearing of the refractive correction. No patient demonstrated significant strabismus. CONCLUSION: An abnormal head posture when not wearing spectacle correction can occur in children who have high hyperopia and insignificant strabismus. This may be a mechanism by which the best visual acuity is obtained (indicated by the disappearance of the abnormal head posture on wearing of the glasses) and also to maintain binocularity (indicated by the disappearance of the abnormal head posture under monocular testing conditions). The presence of a chin-down abnormal head posture should alert the examiner to the possible presence of high hyperopia and therefore the necessity for a cycloplegic refraction.

Child↗

PubMedDate not supplied

Axial length and hyperopia in eyes with retinal vein occlusions.

We performed a prospective study in order to elucidate the predisposing role of axial length and hyperopia in retinal vein occlusions. The study group comprised 39 patients with unilateral central retinal vein occlusion (CRVO), 50 patients with unilateral branch retinal vein occlusion (BRVO), 13 patients with unilateral hemispheric retinal vein occlusion (HRVO) and 45 control eyes. The axial length of affected eyes was compared to fellow eyes and control eyes in each subgroup of patients with retinal vein occlusion. No statistical difference was noted for any of the subgroups (p > 0.05). Hyperopia was detected in 12 of 39 eyes (31%) with CRVO, 14 of 50 eyes (28%) with BRVO, 4 of 13 eyes (31%) with HRVO and 15 of 45 eyes (33%) in the control group. No statistically significant difference was discovered (p > 0.05). In the light of our study, we believe that axial length and hyperopia may not be risk factors in retinal vein occlusions, in contrast to common belief.

Adult↗

PubMed2005

Extreme hyperopia is the result of null mutations in MFRP, which encodes a Frizzled-related protein.

Nanophthalmos is a rare disorder of eye development characterized by extreme hyperopia (farsightedness), with refractive error in the range of +8.00 to +25.00 diopters. Because the cornea and lens are normal in size and shape, hyperopia occurs because insufficient growth along the visual axis places these lensing components too close to the retina. Nanophthalmic eyes show considerable thickening of both the choroidal vascular bed and scleral coat, which provide nutritive and structural support for the retina. Thickening of these tissues is a general feature of axial hyperopia, whereas the opposite occurs in myopia. We have mapped recessive nanophthalmos to a unique locus at 11q23.3 and identified four independent mutations in MFRP, a gene that is selectively expressed in the eye and encodes a protein with homology to Tolloid proteases and the Wnt-binding domain of the Frizzled transmembrane receptors. This gene is not critical for retinal function, as patients entirely lacking MFRP can still have good refraction-corrected vision, produce clinically normal electro-retinograms, and show only modest anomalies in the dark adaptation of photoreceptors. MFRP appears primarily devoted to regulating axial length of the eye. It remains to be determined whether natural variation in its activity plays a role in common refractive errors.

Animals↗

PubMed1998

Autosomal dominant nanophthalmos (NNO1) with high hyperopia and angle-closure glaucoma maps to chromosome 11.

Nanophthalmos is an uncommon developmental ocular disorder characterized by a small eye, as indicated by short axial length, high hyperopia (severe farsightedness), high lens/eye volume ratio, and a high incidence of angle-closure glaucoma. We performed clinical and genetic evaluations of members of a large family in which nanophthalmos is transmitted in an autosomal dominant manner. Ocular examinations of 22 affected family members revealed high hyperopia (range +7.25-+13.00 diopters; mean +9.88 diopters) and short axial length (range 17.55-19.28 mm; mean 18.13 mm). Twelve affected family members had angle-closure glaucoma or occludable anterior-chamber angles. Linkage analysis of a genome scan demonstrated highly significant evidence that nanophthalmos in this family is the result of a defect in a previously unidentified locus (NNO1) on chromosome 11. The gene was localized to a 14.7-cM interval between D11S905 and D11S987, with a maximum LOD score of 5. 92 at a recombination fraction of .00 for marker D11S903 and a multipoint maximum LOD score of 6.31 for marker D11S1313. NNO1 is the first human locus associated with nanophthalmos or with an angle-closure glaucoma phenotype, and the identification of the NNO1 locus is the first step toward the cloning of the gene. A cloned copy of the gene will enable examination of the relationship, if any, between nanophthalmos and less severe forms of hyperopia and between nanophthalmos and other conditions in which angle-closure glaucoma is a feature.

Chromosome Mapping↗