Felix K. Jacobi

The complete form of X-linked congenital stationary night blindness is caused by mutations in a gene encoding a leucine-rich repeat protein

X-linked congenital stationary night blindness (XLCSNB) is characterized by impaired scotopic vision with associated ocular symptoms such as myopia, hyperopia, nystagmus and reduced visual acuity. Genetic mapping in families with XLCSNB revealed two different loci on the proximal short arm of the X chromosome. These two genetic subtypes can be distinguished on the basis of electroretinogram (ERG) responses and psychophysical testing as a complete (CSNB1) and an incomplete (CSNB2) form. The CSNB1 locus has been mapped to a 5-cM linkage interval in Xp11.4 (refs 2,5–7). Here we construct and analyse a contig between the markers DXS993 and DXS228, leading to the identification of a new gene mutated in CSNB1 patients. It is partially deleted in 3 families and mutation analysis in a further 21 families detected another 13 different mutations. This gene, designated NYX, encodes a protein of 481 amino acids (nyctalopin) and is expressed at low levels in tissues including retina, brain, testis and muscle. The predicted polypeptide is a glycosylphosphatidylinositol (GPI)-anchored extracellular protein with 11 typical and 2 cysteine-rich, leucine-rich repeats (LRRs). This motif is important for protein-protein interactions and members of the LRR superfamily are involved in cell adhesion and axon guidance. Future functional analysis of nyctalopin might therefore give insight into the fine-regulation of cell-cell contacts in the retina.

Long-term endothelial cell loss following phacoemulsification through a temporal clear corneal incision

Purpose: To evaluate central endothelial cell loss (ECL) following clear corneal cataract surgery using two different incision sizes and the effect of ultrasound time (UST) and power on postoperative ECL and various cell parameters. Methods: Fifty‐eight patients had phacoemulsification through temporal, two‐step clear corneal tunnel incisions. In Group A (n = 28), a one‐piece, plate‐haptic, foldable silicone intraocular lens (IOL) was implanted through a 3.5 mm sutureless incision. In Group B (n = 30), a poly(methyl methacrylate) IOL was implanted through a 5.0 mm incision with one radial suture. The central endothelial cell counts were recorded preoperatively and postoperatively at 2 to 5 days, after 6 months, and after 1 year. Color‐coded, computer‐assisted specular microscopy was used for special cell analysis after 1 year. Results: Collective data showed an ECL of 7.9 ± 4.1 % (mean ± standard deviation) at 2 to 5 days postoperatively, 6.7 ± 2.9% after 6 months, and 7.3 ± 3.3% after 1 year. A direct linear relationship was found between ECL and UST and power: ECL increased as UST and power increased. After 1 year, ECL in Group A was 4.2% with UST ≤1 1/2 minutes, 6.7% with UST ≥ 1 1/2 to 2 1/2 min, and 9.6% with UST > 2 1/2 to 3 1/2 min; in Group B, it was 6.0%, 7.5%, and 11.4%, respectively. Specular microscopy showed normal, age‐related cell parameters 1 year postoperatively. Conclusions: Phacoemulsification with 3.5 mm clear corneal incisions produced slightly less ECL (6.7%) than phacoemulsification with 5.0 mm incisions (7.9%). Total ECL of 7.3% at 1 year postoperatively compared favorably with ECL rates of other cataract extraction methods.

Pseudophakic retinal detachment in high axial myopia

Purpose: To investigate the effect of extracapsular cataract surgery with intraocular lens (IOL) implantation and neodymium:YAG (Nd:YAG) laser posterior capsulotomy on the rate of retinal detachment (RD) in myopic eyes with an axial length of 27 mm or more. Setting: Department of Ophthalmology, University of Giessen, Germany. Methods: This retrospective, nonrandomized study comprised the records of 386 consecutive surgical procedures in 275 patients performed between December 1985 and December 1993. In May 1994, all patients were asked by a mailed questionnaire whether they had had an RD in either eye or laser treatment for posterior capsule opacification. Responses from 190 patients concerning 253 surgical procedures were evaluated. Results: The pseudophakic RD rate was 0.8% (two cases). One patient developed aphakic RD after IOL mplantation. One expulsive choroidal hemorrhage occurred during secondary IOL implantation. Four eyes (1.6%) had vitreous loss, and 74 eyes (29.2%) had an Nd:YAG capsulotomy. Mean axial length was 29.2 mm ± 1.71 (SD), mean follow‐up was 3.8 ± 2 years, and mean age at surgery was 69.8 ± 12 years. Conclusion: Pseudophakia with no other risk factor posed little additional risk for RD in eyes with high axial myopia; however, Nd:YAG laser posterior capsulotomy was a risk factor for pseudophakic RD. Complicated surgery, such as a secondary procedure or vitreous loss, and young age were major causative factors.

Multifocal Intraocular Lens Implantation in Prepresbyopic Patients with Unilateral Cataract

OBJECTIVE To evaluate the benefits of implantation of a zonal-progressive multifocal intraocular lens (IOL) in prepresbyopic patients with unilateral cataract. STUDY DESIGN Prospective, nonrandomized, comparative trial. PARTICIPANTS Ninety-five eyes of 95 prepresbyopic patients aged between 14 and 40 years with either multifocal or monofocal IOL implantation at two institutions and with more than 6 months follow-up. INTERVENTIONS Temporal clear corneal phacoemulsification and foldable IOL implantation was performed in all eyes. In 54 patients, a zonal-progressive optic multifocal IOL (Array SA40-N, Allergan, Irvine, CA) was implanted, whereas 41 patients received a monofocal IOL and served as controls. RESULTS Preoperative patient demographics, mean postoperative spherical equivalent, astigmatism, and uncorrected and best-corrected distance visual acuities were similar in the two groups. Patients with a multifocal IOL achieved a significantly better uncorrected near visual acuity than patients with monofocal IOL (0.18 versus 0.37; P = 0.0001). With distance correction only, mean near visual acuity was 0.17 versus 0.43 (P = 0.0001). Best-corrected near visual acuity was 0.11 for both groups (P = 0.91), with +1.43 diopters (D) for the multifocal group and +2.35 D for the monofocal group (P = 0.0001). Spectacle dependency differed significantly between the two groups, with 21 patients (51%) of the monofocal group commonly requiring an additional plus add for near tasks compared with 5 patients (9%) in the multifocal group (P = 0.001). Stereopsis was superior in the multifocal group (P < 0.001), with 42 (77%) and 33 (61%) patients with a multifocal IOL responding positively to the Lang and Titmus tests, respectively. In the monofocal group; only 20 (48%) and 9 (22%) patients gave correct answers. CONCLUSIONS Multifocal IOL implantation is a viable alternative to monofocal pseudophakia in prepresbyopic patients with unilateral cataract.

Scleral fixation of secondary foldable multifocal intraocular lens implants in children and young adults

OBJECTIVE To assess the feasibility of transscleral fixation of a foldable, multifocal intraocular lens (IOL) as an alternative form of optical correction to monofocal IOL implantation in aphakic children and young adults intolerant of contact lenses in the absence of sufficient capsular support. STUDY DESIGN Prospective, nonrandomized, comparative trial. PARTICIPANTS Twenty-six eyes of 26 unilateral aphakic patients in the age group 6 to 29 years (mean, 13.2 years) at two university institutions with more than 6 months of follow-up. INTERVENTIONS Anterior vitrectomy and secondary scleral-fixated foldable IOL implantation were performed in all cases. In 12 patients, a zonal-progressive optic multifocal IOL (Array SA40-N; Allergan, Irvine, CA) was implanted, whereas 14 patients received a monofocal IOL (SI40NB; Allergan). The follow-up ranged from 6 to 20 months (mean, 13.4 months). RESULTS Preoperative patient demographics, mean postoperative spherical equivalent, astigmatism, and uncorrected and best-corrected distance visual acuity (BCDVA) were similar in the two groups. After surgery, BCDVA within one Snellen line of the preoperative BCDVA was achieved by 83% of the multifocal group and by 85% of the monofocal group. Patients with a multifocal IOL achieved a significantly better uncorrected near visual acuity than patients with monofocal IOL (019 versus 0.34; P = 0.02). With distance correction only, mean near visual acuity was 0.25 versus 0.44 (P = 0.01). Best-corrected near visual acuity was approximately 0.18 for both groups (P = 0.77), with +1.32 diopters (D) for the multifocal group and +2.54 D for the monofocal group (P = 0.001). Spectacle dependency differed significantly between the two groups, with 10 patients (71%) of the monofocal group commonly requiring an additional plus add for near tasks compared with two patients (16%) in the multifocal group (P = 0.001). The Lang test showed stereopsis to be superior in the multifocal group (P = 0.04). Complications encountered were: pressure increase in three eyes (11.5%), which was permanent in one case (3.8%); marked postoperative anterior chamber reaction in four eyes (15.4%); IOL decentration in five eyes (19.2%), one (3.8%) requiring surgical reintervention; and suture erosion through the conjunctiva in two eyes (7.4%). There was no statistically significant difference between the two groups. CONCLUSIONS Secondary scleral-fixated multifocal IOL implantation was as successful as monofocal IOL implantation in achieving BCDVA comparable with preoperative BCDVA. Moreover, stereopsis, uncorrected and distance-corrected near visual acuities were better in the multifocal patients than in the monofocal eyes. Multifocal IOL seems a viable alternative to monofocal scleral fixation in children and young patients with contact lens-intolerant aphakia.

A novel CACNA1F mutation in a french family with the incomplete type of X-linked congenital stationary night blindness.

PURPOSE To describe a French family with the incomplete type of X-linked congenital stationary night blindness (CSNB2) associated with a novel mutation in the retina-specific calcium channel alpha(1) subunit gene (CACNA1F). DESIGN Interventional case report. METHODS Two family members with a history of nonprogressive night blindness and subnormal visual acuity were clinically examined and the genotype determined by molecular genetic analysis. RESULT Both patients had clinical manifestations characteristic of CSNB2. Electrophysiologically, we found a predominant reduction of the ERG B-wave in the maximal response. Both rod and cone function were subnormal, with the latter tending to be more attenuated. We identified a C deletion at nucleotide position 4548, resulting in a frameshift with a predicted premature termination at codon 1524. CONCLUSIONS The clinical and genetic study of a novel mutation in the CACNA1F gene adds further support to the contention that CSNB2 represents a genetically distinct retinal disorder of a calcium channel.

Silicone intraocular lens implantation in children: preliminary results

PURPOSE To evaluate the safety and outcome of foldable silicone intraocular lens (IOL) implantation in children. SETTING Department of Ophthalmology, University of Giessen, Giessen, Germany. METHODS The results of cataract extraction and silicone IOL implantation in children having surgery between 1992 and 1997 were retrospectively analyzed in 8 eyes (7 patients). All IOLs were implanted in the capsular bag through a 3.5 mm clear corneal incision. In 4 eyes, primary posterior capsulectomy and anterior vitrectomy were performed. RESULTS Mean patient age at the time of surgery was 5.1 years (range 8 months to 15 years). The surgeries were uneventful. All IOLs remained anatomically stable and well centered during the mean follow-up of 29.6 months (range 18 to 46 months). Postoperative inflammatory reaction was minimal. Neither fibrinoid exudation nor posterior synechias occurred postoperatively. Postoperative best spectacle-corrected visual acuity ranged from 20/800 to 20/20. All eyes with an intact posterior capsule developed posterior capsule opacification. In the 4 eyes that had primary posterior capsulectomy and anterior vitrectomy, the visual axis remained clear. CONCLUSIONS These preliminary results suggest that silicone IOL implantation in children is a safe procedure with good and stable short-term anatomic results. Longer follow-up is necessary to answer questions about the long-term safety of silicone lens implantation in a childs eye.

Histological and ultrastructural study of corneal tunnel incisions using diamond and steel keratomes

Purpose: To study the morphology of corneal tunnel incisions using diamond and steel keratomes. Setting: Department of Ophthalmology, University of Giessen, Germany. Methods: Corneal tunnel incisions were performed in six human cadaver eyes using three types of diamond keratomes and a steel keratome. The incision profile and morphology were evaluated and compared using light and scanning electron microscopy. Results: The steel keratome caused more disruption of corneal stromal tissue, while the diamond keratomes produced a more regular, smoother incision. The dissecting incision resulted in a smoother surface of cut stromal tissue than the stab incision. Conclusions: The high quality of corneal tunnel incisions produced with diamond keratomes is the result of their exceptional sharpness, which may have a beneficial effect on wound healing.

Multifocal intraocular lens implantation in patients with traumatic cataract

OBJECTIVE To evaluate the postoperative outcome and complication rate of cataract extraction with implantation of a zonal-progressive multifocal intraocular lens (IOL) for traumatic cataract. DESIGN Prospective, nonrandomized, comparative trial. PARTICIPANTS Fifty-one eyes of 51 subjects with traumatic cataract caused by nonpenetrating, penetrating, and perforating ocular trauma at two university institutions with more than 12 months follow-up. INTERVENTIONS Temporal clear corneal phacoemulsification with foldable IOL implantation was performed in all eyes. In 29 subjects, a zonal-progressive optic multifocal IOL (Array SA40-N Allergan, Irvine, CA) was implanted, whereas 22 subjects received a monofocal IOL and served as controls. RESULTS Preoperative subjects demographics, mean postoperative spherical equivalent, astigmatism, and uncorrected and best-corrected distance visual acuity were similar in the two groups. Subjects with a multifocal IOL achieved a significantly better uncorrected near visual acuity than subjects with monofocal IOL (0.24 vs. 0.40; P = 0.0001). With distance correction only, mean near visual acuity was 0.21 vs. 0.43 (P = 0.0001). Best-corrected near visual acuity was 0.17 for both groups (P = 0.91), with +1.24 diopters (D) for the multifocal group and +2.45 D for the monofocal group (P = 0.0001). Spectacle dependency differed significantly between the two groups, with 18 (81%) subjects of the monofocal group commonly requiring an additional plus add for near tasks compared with 5 (17%) subjects in the multifocal group (P = 0.001). Stereopsis was superior in the multifocal group (P < 0.001), with 20 (69%) and 16 (55%) patients with a multifocal IOL responding positively to the Lang and Titmus tests, respectively. In the monofocal group, only eight (36%) and five (22%) subjects gave correct answers. CONCLUSIONS Multifocal IOL implantation is a viable alternative to monofocal pseudophakia in subjects with traumatic cataract.

Cataract surgery under topical anesthesia in patients with coexisting glaucoma

Purpose: To evaluate and compare levels of patient discomfort and complications during phacoemulsification with implantation of a foldable intraocular lens (IOL) under topical lidocaine hydrochloride in patients with and without various forms of chronic open‐angle and chronic angle‐closure glaucoma. Setting: Two university eye centers in Germany. Methods: This prospective nonrandomized comparative study comprised 176 eyes of 176 patients with various forms of chronic open‐angle glaucoma and chronic angle‐closure glaucoma. Eyes with cataract and without a glaucoma diagnosis or history of intraocular surgery served as a control group (n = 212). All patients received a minimum of 5 doses (2 drops per dose) of topical lidocaine hydrochloride 2% before standard temporal clear corneal phacoemulsification and foldable IOL implantation. No intracameral anesthetic injection was given, and no systemic sedatives were used. The main outcome measures were the number of complications and adverse events. Results: The intraoperative complication rate in all patients (n = 388) was capsule tear, 1.3%; zonule tear, 1.8%; vitreous loss, 1.0%; iris prolapse, 0.8%. No statistically significant differences in intraoperative or early postoperative complications were found between the glaucoma and control groups. The mean pain scores of patients were 0.38 ± 1.1 (SD) in the glaucoma group and 0.36 ± 0.8 in the control group (P = .21) Patient preference for cataract surgery under topical anesthesia was similar in both groups. Conclusions: Surgery‐related complications and patient discomfort were similar in patients with and without glaucoma who had phacoemulsification and IOL implantation under topical anesthesia. These results indicate that topical anesthesia is safe for routine phacoemulsification with foldable IOL implantation in patients with glaucoma and does not compromise patient comfort.