Indications and treatment of keratoconus using epikeratophakia

Nineteen patients with keratoconus underwent epikeratophakia by one of the authors (DSD) and were followed from 3 to 29 months. Patient selection criteria included contact lens failure, and minimal or no central corneal scarring. Uncorrected visual acuity improved by three or more Snellen lines in 13 of 19 patients (68%). Postoperatively, after more than 6 months follow-up, 81% of the patients had best-corrected visual acuity of 20/40 or better. A mean flattening of 4.73 diopters (D) occurred on keratometry readings. There was a mean decrease in refractive cylinder of 2.84 D. Spherical equivalent refraction showed a mean decrease in myopia of 4.64 D. Five patients had postoperative refractive cylinder greater than 4 D requiring relaxing incision(s). With some patients having been followed for more than 2 years, no recurrences of keratoconus have been noted. In properly selected patients, epikeratophakia can effectively be used to treat keratoconus and thus avoid potential intraocular surgical complications and immunogenic phenomena.     

Long-term functional and topographic results seven years after epikeratophakia for keratoconus

PURPOSE: To analyze the long-term effect of epikeratophakia (EKP) on corneal topography and visual acuity of eyes with keratoconus. METHODS: Retrospective study of 36 eyes 7.2 years after EKP. Four eyes underwent penetrating keratoplasty (PKP) and were excluded from further evaluation. Best-corrected visual acuity (BCVA) values were obtained from 32 eyes, corneal refraction and astigmatism from 23 eyes, surface asymmetry index (SAI) and surface regularity index (SRI) from 17 consecutive eyes that were operated upon after 1991, when the Tomey Topographic Modeling System became available. RESULTS: Only four eyes needed PKP. In addition to EKP six eyes had compression sutures and/or relaxing incisions, and one eye underwent photorefractive keratectomy. Mean refractive power of the cornea decreased from 51.8 to 45.8 and astigmatism from 7.2 to 3.8. SAI improved from 3.2 to 0.9 and SRI from 3.7 to 0.9. Mean BCVA was 0.3 preoperatively and 0.6 upon last follow-up. CONCLUSIONS: EKP was able to render PKP unnecessary in 32 of 36 eyes during the entire observation period. It was successful in permanently flattening the ectatic cornea and reducing astigmatism while restoring a symmetrical and smooth corneal surface. As a result, visual acuity improved considerably. In view of the young age of keratoconus patients needing surgery, and the fact that the lifetime of full-thickness corneal grafts is limited, EKP should be considered a valuable alternative to PKP in contact-lens-intolerant cases of keratoconus without central scarring.     

Results of penetrating keratoplasty after epikeratophakia for keratoconus in the nationwide study

In the Nationwide Study of Epikeratophakia, 22 eyes underwent penetrating keratoplasty (PKP) after epikeratophakia for keratoconus. Reasons for PKP included visual acuity unsatisfactory to the patients (6 eyes), recipient corneal scarring (4 eyes), recipient Descemet's folds (3 eyes), scarring in the tissue lens (2 eyes), vascularization of the tissue lens (2 eyes), astigmatism (2 eyes), failure of the tissue lens to reepithelialize (1 eye), corneal ulcer (1 eye), and scarring of the donor and recipient cornea (1 eye). After PKP, all patients had clear grafts and 20/40 or better visual acuity. Average follow-up was 17 months. Three of the 22 patients (13.6%) had graft reaction episodes, all of which were treated successfully, resulting in clear grafts. The authors conclude that previous epikeratophakia does not adversely affect the outcome of subsequent PKP for keratoconus.     

Long-term outcomes of photorefractive keratectomy in eyes with previous epikeratophakia for keratoconus

PURPOSE: To determine the long-term safety and effectiveness of photorefractive keratectomy (PRK) in the treatment of refractive errors after epikeratophakia (EP) for keratoconus. METHODS: Ten patients (14 eyes) who had refractive errors after EP for keratoconus received PRK surgery. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refractive error, corneal astigmatism, pachymetry, corneal topography, and complications were monitored. RESULTS: Mean follow-up after PRK was 63.4 +/- 19.8 months. Mean spherical equivalent was -5.5 +/- 3.9 D before PRK, -0.9 +/- 0.5 D at 1 month after PRK, and -1.5 +/- 1.0 D at 3 years. Mean astigmatism was 4.2 +/- 2.1 D before PRK, 1.2 +/- 0.5 D at 1 month after PRK, and 1.5 +/- 0.6 D at 3 years. Thirteen (93%) eyes had an UCVA <20/40, and 12 (86%) had a BSCVA of 20/40 or better before PRK. At 1 year, the UCVA was 20/40 or better in 8 (57%) eyes, and the BSCVA was 20/40 or better in all eyes. Mean central corneal thickness was 749 +/- 35 microm before PRK and 621 +/- 56 mum at 3 years. During the follow-up period, haze (grade no more than 1.0) was observed in 2 eyes. No immune rejection episode or recurrent keratoconus was found. CONCLUSIONS: PRK appears to be reliable and safe for the correction of residual ametropia after EP for keratoconus, and the visual acuity can remain stable after PRK for a long time.     

Five year follow-up of epikeratophakia in children

Epikeratophakia alters the anterior curvature of the cornea by the addition of a machine-carved donor lenticule. Since March 1980, 88 patients under eight years of age have had epikeratophakia, with at least six months of follow-up. Eighty percent of the original surgeries were successful; some failed grafts were replaced successfully, so that in all, 89% of the patients had successful grafts. The average increase in curvature of the cornea was 14.7 diopters, and the average spectacle overcorrection was +0.56 diopters. In these growing eyes, we documented a myopic shift of 1.5 diopters per year. Visual acuity results varied with the timing of refractive surgery, density of the amblyopia, and the parents' ability to maintain the patching schedule. The largest group of children were those who had unilateral traumatic cataracts. In this group, 7 of 15 patients who had surgery under 4 years of age had final verbal acuities of 20/40 or better. Long-term follow-up has demonstrated that epikeratophakia safely and successfully corrects refractive errors in aphakic children either as a primary procedure, or as a secondary procedure after cataract extraction.     

Ten-year follow-up of epikeratophakia for the correction of high myopia

OBJECTIVE: To determine the long-term functional results of epikeratophakia for myopic patients. DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Twenty-two patients (32 eyes; average age, 43+/-6 years) who underwent epikeratophakia surgery for high myopia. Mean preoperative myopia was -18.74+/-9.16 diopters (D; range, -7 D to -49 D). Follow-up was 12+/-2 years. MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), change in mean keratometry, visual acuity under glare conditions, BCVA versus potential acuity meter reading, and patient satisfaction with the visual outcome. RESULTS: Mean preoperative UCVA increased from 20/800+/-20/400 (range, counting fingers-20/400) to 20/80+/-20/200 (range, 20/250-20/32) in 24 eyes. Mean preoperative BCVA of 20/32+/-20/64 increased only in five eyes, whereas six eyes had no change and 18 eyes had a more than one line loss of Snellen BCVA. Mean preoperative keratometry reading decreased from 43.67+/-0.90 D (range, 41.0-46.25 D) to 37.40+/-2.92 D (range, 29.43-47.68 D). In the presence of glare, mean BCVA decreased to 20/100+/-20/100 (range, counting fingers-20/32). Potential acuity meter (PAM) readings were significantly (P<0.05) higher than BCVA. Mean PAM reading was 20/25+/-20/100 (range, 20/100-20/16). Seven patients (11 eyes) were extremely satisfied with the operative result more than 10 years after the operation, whereas four patients (four eyes) were not satisfied at all. CONCLUSIONS: Epikeratophakia for the correction of myopia improved UCVA significantly, but BCVA decreased. The removal of the lenticules in patients who were not satisfied with their visual acuity was uncomplicated, and acceptable vision could be achieved with either contact lenses or intraocular lens implantation.     

Long-term follow-up of wound healing following epikeratophakia in rabbits

Epikeratophakia was performed on rabbit corneas using cryolathed keratolens and histological examinations were performed after long-term follow-up. On days 254 and 360 after the operation, pachymetry was performed, and corneas were excised, labeled with 3H-proline (10 muCi/ml) in DME for 4 hours, fixed by 2% glutaraldehyde and analyzed histologically using light and electron microscopy and by autoradiography. The results of pachometry revealed that postoperative increases of the corneal thickness on days 254 and 360 were both smaller than the expected value, 350 microns. However, on days 254 and 360, collagen fibril density (CFD) in the keratolens stroma to 95% and 99% of that of the control cornea (264 +/- 16/microns2). On day 254, activated keratocytes with well developed rough endoplasmic reticulum which were suggestive of active collagen production and keratocytes with extended pseudopoidia that suggested phagocytic activity were observed in the keratolens stroma. On day 360, most keratocytes in the keratolens stroma revealed a normal shape. In the epithelium over the keratolens, poor differentiation of basal cells and irregularity or lack of basement membrane were still observed. At both postoperative periods, the endothelium showed no remarkable morphologic abnormality on histological analysis under light and electron microscopy. These findings and the results of our previous study indicated that the reconstruction of the keratolens stroma continued for about one year postoperatively and complete healing after epikeratophakia including epithelial repair needs more than one year.     

Intacs for the correction of keratoconus: two-year follow-up

PURPOSE: To evaluate the long-term safety and efficacy of Intacs segments (Addition Technology, Inc.) for the treatment of keratoconus in terms of intraoperative and postoperative complications, visual outcome, restoration of contact lens tolerance, and inhibition of disease progression. SETTING: Service d'Ophtalmologie, CHU Pellegrin, Bordeaux, France. METHODS: This prospective, 2-year follow-up study comprised 100 keratoconic eyes with clear central corneas and contact lens intolerance. The best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity (UCVA), refractive error, keratometry, pachymetry, and slitlamp examination were assessed preoperatively and 1 and 2 years after Intacs implantation. RESULTS: At 2 years, the UCVA and BCVA improved in 80.5% and 68.3% of eyes, respectively (P<.001). The proportion of eyes with a BCVA >or=0.5 (20/40) increased from 22.0% at baseline to 51.2% and 53.7% at 1 year and 2 years, respectively (P<.001). The manifest refraction spherical equivalent improved from a mean of -6.93 diopters (D) +/- 3.91 (SD) preoperatively to -4.01 +/- 3.16 D at 1 year and -3.80 +/- 2.73 D at 2 years (P<.001). The mean keratometry readings decreased from 50.1 +/- 5.6 D preoperatively to 46.4 +/- 5.3 D at 1 year and 46.8 +/- 4.9 D at 2 years (P<.001). Contact lens tolerance was restored in over 80% of cases. Postoperative slitlamp observations revealed no clinically significant issues. The segments were removed from 4 eyes without complications or sequelae. CONCLUSION: Intacs implantation was a safe and efficacious treatment for keratoconus. Significant and sustained improvements in objective visual outcomes were achieved in most cases, with restoration of contact lens tolerance.     

准分子激光角膜切削术治疗圆锥角膜行角膜表层镜片术后的屈光不正

目的探讨角膜表层镜片术（EP）联合Ⅱ期准分子激光角膜切削术（PRK）治疗圆锥角膜完成期的临床疗效。方法（1）病例入选标准：①EP入选标准：圆锥角膜完成期患者,角膜中央区无瘢痕,最佳矫正视力（BCVA）≤0．3,角膜曲率≤60．0D;②Ⅱ期行PRK入选标准：角膜拆线后3个月内散光变化〈0．5D,年龄〉18岁,无其他眼部疾病。（2）手术治疗：对进入手术入选标准的患者常规Ⅰ期行EP,Ⅱ期行PRK。（3）术后随访：观察术后植片情况,记录视力、散光变化及并发症发生情况。结果8例（10只眼）患者接受了Ⅰ期EP联合Ⅱ期PRK,术后平均随访时间为40．6（30～94）个月。（1）视力：EP术后12～18个月（角膜全拆线行PRK术前）,10只眼BCVA均〉0．3,其中0．3～0．5者1只眼,≥0．5者9只眼;行PRK术后〉12个月,10只眼BCVA均≥0．5,其中5只眼BCVA达到1．0。（2）角膜散光：EP术前平均角膜散光为（7．3±1．8）D,EP术后12～18个月平均角膜散光为（3．8±1．6）D,PRK术后24个月以上,平均角膜散光为（1．6±0．9）D。（3）植片情况：EP术后所有植片透明,无免疫排斥反应发生。PRK术后1只眼发生0．5级的角膜上皮下雾状混浊,未见圆锥角膜复发。（4）术后并发症与处理：1例（1只眼）患者EP术后当天继发青光眼,前房消失,急诊行前房重建后缓解;1例（1只眼）患者EP术后植床出现较大皱褶,1例（1只眼）患者EP术后3个月内缝线松动,行植片重缝后缓解。结论Ⅰ期EP联合Ⅱ期PRK可能是治疗圆锥角膜完成期的有效方法,行PRK术后视力长期稳定。     

One-year follow-up evaluation of combined phacovitrectomy for idiopathic epiretinal membrane

AIM: To study the imaging characteristics of lacrimal punctum lesions with optical coherence tomography (OCT), and provide imaging basis for the diagnosis and treatment of lacrimal punctum diseases. METHODS: A total of 25 patients (28 eyes) with epiphora and lacrimal punctum lesions were enrolled. Lacrimal punctum lesions included: punctum membrane obstruction in 7 cases (9 eyes), punctum agenesis in 1 case (1 eye), a mass protruded from the punctum in 1 case (1 eye), slit puncta in 1 case (1 eye), peripunctal mass in 2 cases (2 eyes), chronic dacryocystitis in 4 cases (4 eyes), and primary punctum stenosis in 9 cases (10 eyes; 3 eyes mild, 4 eyes moderate and 3 eyes severe). All patients were examined by slit lamp microscopy and OCT to observe the morphological characteristics of abnormal punctum.RESULTS: Two types of complete membrane obstruction and incomplete membrane obstruction of punctum were observed in OCT images of 7 patients. No lacrimal punctum and lacrimal canalicular cavity were found in 1 case with punctum agenesis. OCT images showed that a narrow lumen remained in the lacrimal puncta in 1 patient with a mass protruded from the punctum. OCT of punctum in a patient with slit puncta after stent placement showed stent and abnormal lacrimal structure. No abnormal intraluminal structure was found in 2 cases of peripunctal mass after OCT scan, and the lacunar space was narrower than that of the contralateral eye. OCT of punctum in 4 patients with chronic dacryocystitis showed that pus floated in tear with lump-like medium-low reflex. In 9 patients with primary lacrimal punctal stenosis, OCT image could clearly show the changes of punctum lumen in different degrees and shapes. CONCLUSION: OCT is feasible for the examination of pathological punctum, and can provide imaging basis for the diagnosis and treatment of punctum diseases.     

Intracorneal ring segments for keratoconus correction: long-term follow-up

PURPOSE: To evaluate long-term results and stability of intracorneal ring segment (Intacs) implantation for keratoconus correction. SETTING: Vissum, Instituto Oftalmológico de Alicante and University of Miguel Hernandez, Alicante, Spain. METHODS: This retrospective study comprised 13 eyes operated on between April 2000 and December 2001 that had Intacs implantation for keratoconus correction. The outcomes were evaluated at 6, 12, 24, and 36 months in all eyes and at 48 months (6 eyes). RESULTS: Mean best spectacle-corrected visual acuity (BSCVA) increased from 0.46 (20/50) preoperatively to 0.66 (20/30) postoperatively (P< or =.001). Mean decrease of inferior-superior (I-S) asymmetry was 2.81 diopters (D) (P< or =.02), and the average K-value was 3.13 D (P< or =.001). Mean difference between 6 and 36 months (stability) showed no significant difference regarding BSCVA (P< or =.5) and I-S asymmetry (P< or =.6). Although a significant increase was noticed in the average K by 1.67 D (P< or =.002), at 36 months it did not reach the initial preoperative values. CONCLUSION: Intacs increased the BSCVA and decreased I-S asymmetry with stability up to 36 months. In spite of the decrease of the K-values at 6 months, a further significant increase was detected 36 months after surgery.     

Corneal collagen crosslinking for progressive keratoconus in Saudi Arabia: One-year controlled clinical trial analysis

Aims

To determine the short-term efficacy of corneal collagen crosslinking (CXL) treatment in patients with progressive Keratoconus (KCN) in comparison with no treatment.

Settings and design

This controlled clinical trial study was carried out at a tertiary eye hospital, Eastern Province, Saudi Arabia.

Methods and material

A prospective controlled clinical study of patients being treated for Keratoconus at a tertiary eye care hospital in the Eastern province of Saudi Arabia. 51 eyes of 43 patients with progressive KCN who received corneal collagen crosslinking (treatment group) and 50 eyes of 34 patients with KCN and no treatment (control group) were included in our study. A one year clinical data were collected preoperatively as well as at 1, 3, 6 and 12 months postoperatively for the treatment group patients. A baseline and 1 year clinical data were collected for the control group patients. The short-term efficacy of the treatment in preventing progression of KCN in comparison with no treatment was analysed at one year.

Results

At one year after crosslinking there was significant flattening of the average keratometry by 0.61 D (p = 0.001) [95% CI: 0.25, 0.97] compared to 0.40 D (p = 0.210) steepening in the control group; difference between treatment and control was 1.01 D (p = 0.006) [95%CI: 0.29, 1.72]. Pachymetry in treatment group thinned by 20.21 μm (p < 0.0001) [95% CI: 12.77, 27.66] compared to 0.32 μm (p = 0.912) in the control group. Visual acuity remained stable at the preoperative level of 20/30 (p = 0.397) in the treatment group and 20/40 (p = 0.553) in the control group at one year.

Conclusions

Corneal CXL is an effective treatment for halting the progression of KCN as shown by reduced keratometry and stability of vision.     

One-year follow-up of selective laser trabeculoplasty in open-angle glaucoma

BACKGROUND: Selective laser trabeculoplasty (SLT) targets the pigmented trabecular meshwork (TM) cells without damage to the adjacent non-pigmented tissue. A study was conducted to evaluate the efficacy and safety of SLT in the treatment of uncontrolled open-angle glaucoma. METHODS: In a prospective non-randomized study 44 eyes of 31 patients with uncontrolled open-angle glaucoma were treated with a frequency-doubled, Q-switched Nd:YAG laser. A total of approximately 50 spots were placed over 180 degrees of the TM at energy levels ranging from 0.7 to 0.9 mJ. Intraocular pressure (IOP) was measured 1, 2, and 24 h, 1 and 2 weeks and 1, 2, 3, 6, 9, and 12 months after treatment. RESULTS: The average pre-operative IOP was 25.6 (SD 2.6) mm Hg (range 22-34). The mean IOP reduction from baseline at 24 h, 3, 6 and 12 months was 7.1 mm Hg (SD 3.5) or 27.6%; 4.2 mm Hg (SD 3.5) or 16.4%; 4.7 mm Hg (SD 4.2) or 18.6%, and 4.4 mm Hg (SD 3.8) or 17.1%, respectively. The percent of eyes with IOP reduction of 3 mm Hg or more at 3, 6 and 12 months was 66, 78 and 62%. A pressure spike of 8 mm Hg or more was detected in 4 eyes (9.1%). Anterior chamber reaction was seen 1 h after SLT and was mild to moderate in 16 eyes (40.4%) and marked in 3 eyes (6.8%). CONCLUSIONS: SLT has shown reasonable efficacy in lowering IOP over 1-year follow-up, but there was a tendency for IOP to increase with a longer follow-up. Long-term follow-up studies with a large sample size are needed to determine whether the IOP lowering effect is sustained over time, and to assess the efficacy of repeated SLT.