Biomechanics in DALK: Big bubble vs manual lamellar dissection / Biomecânica no DALK: grande bolha versus dissecção manual lamelar

ABSTRACT Purpose: The present study's aim was to compare the biomechanical properties of corneal tissue in patients who underwent deep anterior lamellar keratoplasty (DALK) surgery, with successful big bubble formation and manual lamellar dissection, during failed big bubble formation. Methods: This retrospective comparative study included 60 eyes from 60 keratoconus patients who previously underwent DALK surgery. These patients were categorized as big bubble (+) or big bubble (−) based on the success or failure of big bubble formation during the surgery. The big bubble (+) group included 42 eyes, while the big bubble (−) group had 18 eyes. Moreover, the patients were regrouped as 0.25 mm and 0.50 mm to evaluate the effects of the disparity between donor and trephine punches on the biomechanical properties of the cornea. These biomechanical properties, characterized by corneal hysteresis and the corneal resistance factor, were measured using the Ocular Response Analyzer 12 months after the surgery. Results: There was no statistically significant difference between the big bubble (+) and big bubble (−) groups in the biomechanical properties of the cornea (corneal hysteresis: 10.06, 10.25; p=0.716/corneal resistance factor: 10.15, 10.07; p=0.805, respectively). In addition, pachymetry results were not statistically different between the two groups. Multivariate regression analysis revealed that corneal hysteresis and corneal resistance factor were positively associated with central corneal thickness (p<0.001/r2=0.506; p<0.001/r2=0.561, respectively). However, the study did not demonstrate a relationship between any of the punch sizes and corneal hysteresis or between the punch sizes (p=0.673) and the corneal resistance factor (p=0.643). Conclusions: The corneal hysteresis and corneal resistance factor values were similar in big bubble and manual lamellar dissection after DALK. Thus, manual lamellar dissection was not a disadvantage considering the cornea's biomechanical properties.

RESUMO Objetivo: O objetivo do estudo foi comparar pa râmetros biomecânicos corneanos de pacientes com cirurgia de ceratoplastia lamelar anterior profunda com formação bem-sucedida de bolha e dissecção lamelar manual, frente à falha de formação da grande bolha. Métodos: Este estudo comparativo retrospectivo incluiu 60 olhos de 60 pacientes com ceratocone submetidos à cirurgia de ceratoplastia lamelar anterior profunda. Os pacientes foram agrupados como grande bolha (+) e grande bolha (-) de acordo com o sucesso da formação da grande bolha durante a cirurgia. O grupo grande bolha (+) incluiu 42 olhos, enquanto o grupo grande bolha (-) tinha 18 olhos. Além disso, para a avaliação dos efeitos da disparidade entre alterações individuais nas propriedades biomecânicas da córnea, reagrupamos os pacientes em 0,25 mm e 0,50 mm. Parâmetros biomecânicos da córnea, caracterizados por histerese corneana e fator de resistência corneana foram medidos com o ORA 12 meses após a cirurgia. Resultados: Não houve diferença estatisticamente significativa entre os grupos grande bolha (+) e grande bolha (-) em relação aos parâmetros biomecânicos da córnea (histerese corneana: 10,06, 10,25, p=0,716/fator de resistência da córnea: 10,15, 10,07, p=0,805, respectivamente). Além disso, os resultados de paquimetria não diferiram estatisticamente entre os dois grupos. A análise de regressão multivariada demonstrou que a histerese da córnea e o fator de resistência corneana estavam associados positivamente com a espessura corneana central (p<0,001/r2=0,506, p<0,001/r2=0,561 respectivamente). No entanto, o estudo não revelou associação entre qualquer um dos tamanhos de punção e histerese corneana, bem como entre os tamanhos de punção e o fator de resistência corneano (p=0,673, p=0,643). Conclusões: A histerese da córnea e os valores do fator de resistência da córnea foram comparáveis com formação de grande bolha e dissecção manual lamelar na ceratoplastia lamelar anterior profunda. Assim, a dissecção manual lamelar não foi uma desvantagem, considerando os fatores biomecânicos da córnea.

Biomechanics in DALK: Big bubble vs manual lamellar dissection.

PURPOSE: The present study's aim was to compare the biomechanical properties of corneal tissue in patients who underwent deep anterior lamellar keratoplasty (DALK) surgery, with successful big bubble formation and manual lamellar dissection, during failed big bubble formation. METHODS: This retrospective comparative study included 60 eyes from 60 keratoconus patients who previously underwent DALK surgery. These patients were categorized as big bubble (+) or big bubble (-) based on the success or failure of big bubble formation during the surgery. The big bubble (+) group included 42 eyes, while the big bubble (-) group had 18 eyes. Moreover, the patients were regrouped as 0.25 mm and 0.50 mm to evaluate the effects of the disparity between donor and trephine punches on the biomechanical properties of the cornea. These biomechanical properties, characterized by corneal hysteresis and the corneal resistance factor, were measured using the Ocular Response Analyzer 12 months after the surgery. RESULTS: There was no statistically significant difference between the big bubble (+) and big bubble (-) groups in the biomechanical properties of the cornea (corneal hysteresis: 10.06, 10.25; p=0.716/corneal resistance factor: 10.15, 10.07; p=0.805, respectively). In addition, pachymetry results were not statistically different between the two groups. Multivariate regression analysis revealed that corneal hysteresis and corneal resistance factor were positively associated with central corneal thickness (p<0.001/r2=0.506; p<0.001/r2=0.561, respectively). However, the study did not demonstrate a relationship between any of the punch sizes and corneal hysteresis or between the punch sizes (p=0.673) and the corneal resistance factor (p=0.643). CONCLUSIONS: The corneal hysteresis and corneal resistance factor values were similar in big bubble and manual lamellar dissection after DALK. Thus, manual lamellar dissection was not a disadvantage considering the cornea's biomechanical properties.

Bilateral cloudy cornea: is the usual suspect congenital hereditary endothelial dystrophy or stromal dystrophy?

We provide the diagnosis, treatment and follow-up period of a patient with cloudy cornea in both eyes from birth. A 4-year-old girl presented with blurring in both eyes. Penetrating keratoplasty (PK) was performed with the preliminary diagnosis of congenital hereditary endothelial dystrophy in June 2012. According to the pathology report for extracted host tissue, the Descemet's membrane (DM) and endothelium were healthy and diagnosis was reported to be congenital hereditary stromal dystrophy. Deep anterior lamellar keratoplasty was performed on the left eye. The DM was transparent at follow-up. Cornea transplantation is the only choice to provide visual rehabilitation in children with congenital cloudy cornea. However, it is known that the prognosis of traditional PK in the paediatric age group is not good. Therefore, when using alternative keratoplasty (deep anterior lamellar keratoplasty, Descemet's stripping automated endothelial keratoplasty) options, pathological examination of the host tissue should be made.

Clinical outcomes of trabeculectomy vs. Ahmed glaucoma valve implantation in patients with penetrating keratoplasty : (Trabeculectomy vs. Ahmed galucoma valve in patients with penetrating keratoplasty).

The aim of this study was to compare the visual outcomes, intraocular pressure (IOP), and endothelial cell loss caused by trabeculectomy (TRAB) and Ahmed glaucoma valve (AGV) implantation in patients who had previously undergone penetrating keratoplasty (PKP). The data from all patients who underwent surgical treatment of glaucoma after PKP were reviewed at the Cornea Department of Haydarpasa Numune Education and Research Hospital. Eighteen patients who had undergone surgical treatment of glaucoma after PKP were included in this retrospective study. Time between PKP and glaucoma surgeries, visual acuity results, IOP results, endothelial cell counts (ECC) before the surgery, at 1st, 6th, and 12th month of surgery were recorded. Differences between two groups were evaluated. Mean loss of ECC was 315 cells/mm(2) in the AGV group and 197 cells/mm(2) in TRAB group at 12th month of glaucoma surgery. The difference between endothelial cell loss at 12th month of surgery was statistically significant and higher in AGV group (p < 0.001). The decrease in IOP was 64.2 % in AGV group and 46.9 % in TRAB group at 12th month of surgery. Both differences were statistically significant between 2 groups (p = 0.001, 0.001). TRAB successfully decreased both the IOP and endothelial cell loss in patients with post-PKP glaucoma. Ahmed glaucoma valve had a significantly better IOP lowering but higher endothelial cell loss effect.

Visual acuity and endothelial cell density with respect to the graft thickness in Descemet's stripping automated endothelial keratoplasty: one year results.

AIM: To evaluate the visual acuity and endothelial cell density according to the thickness in Descemet's stripping automated endothelial keratoplasty (DSAEK) one year after surgery. METHODS: DSAEK patients' data were reviewed. Thirty-seven eyes of 37 patients who underwent DSAEK for pseudophakic bullous keratopathy (PBK) were included in this study. Graft thickness was measured with optical coherence tomography (OCT) 12mo after DSAEK. Eyes were divided into 3 groups based on the graft thickness: thick (>200 µm), medium-thick (150-200 µm) and thin (<150 µm). Best corrected visual acuity (BCVA), endothelial cells density (ECD) and complications were assessed and comparisons were done between groups. RESULTS: There was no significant difference in age, sex, preoperative BCVA, or follow-up period between DSAEK groups. At postoperative 12mo, mean BCVA was 0.28±0.10 in thick graft group, 0.52±0.08 in medium-thick graft group, and 0.72±0.06 in thin graft group. Thin grafts showed better postoperative BCVA as compared with the medium-thick and thick grafts (P=0.001). Thick graft group had 1637.44±88.19-mm(2), medium thick graft had 1764.50±34.28-mm(2) and thin graft group had 1845.30±65.62-mm(2) ECD at 12mo after the surgery. Thin graft group had better ECD at 12mo after surgery (P=0.001). CONCLUSION: Thin grafts after DSAEK ensure better visual rehabilitation. Eyes with thin grafts had significantly lesser loss of ECD compared to eyes with medium-thick and thick grafts one year after surgery.

Can the effect of transepithelial corneal collagen cross-linking be improved by increasing the duration of topical riboflavin application? An in vivo confocal microscopy study.

OBJECTIVE: To evaluate the effect of transepithelial corneal collagen cross-linking (CXL) with prolonged riboflavin application by in vivo confocal microscopy and to compare this effect with that of standard CXL with complete epithelial debridement. METHODS: In eyes with progressive keratoconus, CXL procedure was performed with standard technique and transepithelial technique after prolonged riboflavin drop application for 2 hr. Patients were evaluated with in vivo confocal microscopic examination preoperatively and at postoperative months 1 and 6. RESULTS: The depth of CXL effect was similar in both groups (i.e., 380.86 ± 103.23 µm in standard CXL group and 342.2 ± 68.6 µm in transepithelial CXL group) (P=0.4). The endothelial cell counts and morphological parameters (i.e., pleomorphism and polymegathism) were not significantly affected in both groups (P>0.05 for all). In the standard CXL group, in vivo confocal microscopy revealed anterior stromal acellular hyperreflective honeycomb edema with posteriorly gradually decreasing reflectivity and increasing number of keratocytes and some sheets of longitudinally aligned filamentary deposits. The keratocytes were seen to repopulate in the posterior-to-anterior direction. In transepithelial CXL group, although the depth of CXL effect was similar, less pronounced keratocyte damage, extracellular matrix hyperreflectivity, and sheets of filamentary deposits at the posterior stroma was observed. CONCLUSIONS: Transepithelial CXL with prolonged peroperative riboflavin application can achieve similar depth of effect in the stroma with less pronounced confocal microscopic changes as compared with the standard CXL with complete epithelial debridement.

Comparison of sulfur hexafluoride and air for donor attachment in Descemet stripping endothelial keratoplasty in patients with pseudophakic bullous keratopathy.

PURPOSE: The aim of this study was to evaluate the clinical efficacy and safety of sulfur hexafluoride (SF6) as a tamponading agent after donor placement during Descemet stripping endothelial keratoplasty (DSEK) surgery and to compare the outcomes with those of air. METHODS: Forty-four eyes of 44 consecutive patients who underwent DSEK were included in the study. Air was used in 22 eyes of 22 patients (air group), and SF6 was used in 22 eyes of 22 patients (SF6 group) to attach the donor lenticule. The complications, corrected visual acuity (CVA), and the endothelial cell density (ECD) results were compared between these 2 groups. RESULTS: Six eyes had graft dislocation in the air group that underwent successful rebubbling on postoperative day 1. There was no graft dislocation in the SF6 group. There was no other complication observed in both the groups. The mean increase in the CVA was 1.09 ± 0.36 logarithm of the minimum angle of resolution in the air group, whereas it was 0.80 ± 0.57 logarithm of the minimum angle of resolution in the SF6 group. The mean increase in the CVA was not statistically different between the 2 groups (P = 0.060). Compared with the mean ECD in donor grafts, the mean decrease in the ECD was 222 ± 86 (44%) cells per square millimeter in the air group and 178 ± 52 (39%) cells per square millimeter in the SF6 group at the 1-year follow-up. The mean decrease in the ECD was statistically significantly higher in the air group compared with that in the SF6 group (P = 0.049). CONCLUSIONS: SF6 is comparable to air for attaching the donor graft as a tamponading agent in DSEK surgery.

The effect of different doses of subconjunctival bevacizumab injection on corneal neovascularization.

To evaluate the effects of various doses of subconjunctival bevacizumab injections in the treatment of patients with corneal neovascularization. During the 6-month-follow-up, no significant ocular or systemic adverse events were observed related to the subconjunctival bevacizumab injection. In Group 1, the total area of corneal neovascularization before injection was 14.8 ± 3.2 % of the corneal surface and 10.2 ± 2.8 % 6 months after injection (p < 0.01). The mean decrease in Group 1 was 32.0 ± 3.0 %. In Group 2, the total area of corneal neovascularization before and 6 months after the injection was 14.2 ± 2.5 and 9.8 ± 2.3 %, respectively (p < 0.01). The mean decrease in Group 2 was 31.0 ± 2.3 %. The difference between the two groups was not statistically significant (p > 0.05). Twenty-four eyes of 24 patients with corneal neovascularization who were treated with a subconjunctival injection of bevacizumab were included in this retrospective study. Fourteen eyes were treated with 2.5 mg/0.1 ml (Group 1), and 10 eyes were treated with 5.0 mg/0.2 ml (Group 2) of subconjunctival bevacizumab. Digital photographs of the cornea were used to determine the area of corneal neovascularization before injection and at 1 month, 3 months, and 6 months after treatment. Subconjunctival injection of bevacizumab is well tolerated and associated with a partial regression of corneal neovascularization. The efficacy of this treatment is not correlated to the injection dose.

Ability of fourier-domain optical coherence tomography to detect retinal ganglion cell complex atrophy in glaucoma patients.

PURPOSE: To evaluate the diagnostic ability of Fourier-domain optical coherence tomography (FD-OCT) measurements in both normal individuals and patients with different stages of glaucoma. PATIENTS AND METHODS: A total of 113 patients diagnosed with glaucoma and classified into different stages of glaucoma according to Glaucoma Staging System 2 and 30 healthy individuals were included in this study. In all patients, parameters of both the retinal ganglion cell complex (GCC) and the peripapillary retinal nerve fiber layer were measured by FD-OCT (RTVue-100). Comparisons were made from measurements in patients with different stages of glaucoma. RESULTS: Both GCC and retinal nerve fiber layer thickness values of patients with glaucoma were statistically significantly lower compared with those of healthy individuals. As the stage of glaucoma progressed, the mean GCC and retinal nerve fiber layer thickness values decreased. CONCLUSIONS: GCC and retinal nerve fiber layer thickness measurements performed by FD-OCT showed high diagnostic ability in detecting glaucoma. Mean thickness values can be determined for each glaucoma stage.

Fixed dilated pupilla as a common complication of deep anterior lamellar keratoplasty complicated with Descemet membrane perforation.

PURPOSE: To report 8 cases of fixed dilated pupilla (FDP) (Urrets-Zavalia syndrome) following deep anterior lamellar keratoplasty (DALK) with Descemet membrane (DM) perforation and change of management to avoid FDP. METHODS: Retrospective analysis of 106 eyes of 94 patients who underwent DALK for various diagnoses was performed. Intraoperative and postoperative details of eyes that developed DM detachment, FDP, as well as change of management to prevent rise of intraocular pressure (IOP) (as a common trait of these eyes) were evaluated. RESULTS: Descemet membrane perforation developed in 17 (16%) eyes. Fixed dilated pupilla was diagnosed in 8 (7.5%) eyes. Seven of the eyes with FDP experienced DM perforation and air bubble was left in anterior chamber (AC) to tamponade DM perforation at the end of the surgeries. Five eyes developed FDP in the early postoperative period and the remaining 2 eyes, which were diagnosed as double AC and managed by repeated air injections, developed FDP in the third postoperative week. The last patient who experienced intense postoperative inflammation had a fixed dilated pupil in the third postoperative week. CONCLUSIONS: Fixed dilated pupilla is an uncommon but well-known complication of keratoplasty. The exact mechanism remains unknown but postoperative high IOP seems to be an important risk factor following complicated DALK. Rise in IOP during the management of complications following DALK related to DM was found to be important in the development of FDP in this series.

Corneal biomechanical properties in eyes with no previous surgery, with previous penetrating keratoplasty and with deep anterior lamellar keratoplasty.

PURPOSE: To compare the biomechanical properties of the cornea in eyes with no previous surgery, with keratoconus with previous penetrating keratoplasty (PK) and with keratoconus with previous deep anterior lamellar keratoplasty (DALK) using the Reichert Ocular Response Analyzer (ORA). METHODS: One hundred twenty eyes of 120 patients were included in this prospective comparative study. Forty eyes were with no previous ocular surgery (group 1), 40 eyes were with previous PK for keratoconus (group 2), and 40 eyes were with previous DALK for keratoconus (group 3). Corneal hysteresis (CH) and the corneal resistance factor (CRF) were measured with ORA. RESULTS: The CH and CRF values in group 2 were significantly lower than in group 1 and group 3 (p = 0.001). The CH and CRF values were similar in group 1 and group 3. There was no statistically significant difference between group 1 and 3. CONCLUSION: Although the post-PK keratoconus cornea has weaker biomechanical properties, post-DALK keratoconus cornea is similar to normal cornea. A cornea weakened by keratoconus can be strengthened with lamellar keratoplasty.

Management of detached graft donor by SF6 injection following Descemet stripping automated endothelial keratoplasty of an eye with iridocorneal endothelial syndrome and Ahmed glaucoma drainage tube.

A 65-year-old woman with iridocorneal endothelial syndrome and a history of Ahmed glaucoma drainage (AGD) tube implantation underwent Descemet stripping automated endothelial keratoplasty (DSAEK) in her right eye. During the procedure, filling the anterior chamber with air was quite difficult due to escape of air via the AGD tube and a complete air fill of the anterior chamber could only be managed after multiple attempts. On operation night, there was no air left in the anterior chamber. On postoperative day 1, graft detachment was determined by slit-lamp biomicroscopy. For rebubbling, sulfur hexafluoride (SF(6)) 20 % was injected into the anterior chamber. Two days later, there was still some SF(6) in the anterior chamber and the graft was completely attached. At postoperative week 2, visual acuity was 2/10. SF(6) use may be considered for DSAEK in cases of previous AGD tube implantation history due to its potential for longer duration in order to obtain a better tamponade with the bubble due to its expanding nature.

Is it really important to form a big bubble in DALK to enhance the visual acuity?

OBJECTIVES: The aim of this study was to investigate the prognosis of visual acuity (VA) in the patients with keratoconus, who underwent deep anterior lamellar keratoplasty (DALK) with a successful big bubble or lamellar dissection. METHODS: Sixty-eight eyes of 60 patients with keratoconus, who underwent DALK using the big-bubble technique, were enrolled in this retrospective comparative study. The VA and refractive errors were assessed before the operation and, thereafter, at months 1, 3, 6, and 12 after the operation (1) in the patients who achieved a big-bubble formation, and in those who required layer-by-layer lamellar dissection (2) to reach the Descemet membrane. RESULTS: Successful big bubble was achieved in 50 eyes (73.5 %) (group 1), and lamellar dissection was performed in 18 eyes (26.5 %) (group 2). The mean follow-up period was 22.4±6.2 months in group 1 and 23.7±7.8 months in group 2 (P=0.562). Although best-corrected visual acuity (BCVA) values observed at months 1 and 3 were significantly higher in group 1 than in group 2 (P=0.016 and P=0.024, respectively), there was no statistically significant difference between the two groups for BCVA values observed at months 6 and 12 (P=0.412 and P=0.528, respectively). CONCLUSIONS: Although the visual recovery was delayed in the early postoperative follow-up because of residual stroma in lamellar dissection, the final results were comparable between the achievement of big-bubble formation and lamellar dissection.

Laser in situ keratomileusis to manage refractive errors after deep anterior lamellar keratoplasty.

PURPOSE: To analyze the visual and refractive outcomes of laser in situ keratomileusis (LASIK) after deep anterior lamellar keratoplasty (DALK) for keratoconus. SETTING: Haydarpasa Numune Education and Research Hospital, Ophthalmology Clinic, Istanbul, Turkey. DESIGN: Cohort study. METHODS: Patients with compound myopic astigmatism after DALK and a spherical equivalent (SE) between -2.50 diopters (D) and -8.00 D had LASIK as a single-step procedure, correcting the manifest refraction error. The visual and refractive results at 1 month, 3 months, and the last follow-up were compared with preoperative values. RESULTS: The mean follow-up was 11.17 months ± 3.61 (SD). The mean manifest refraction SE (MRSE) and autorefractometer measurements and the autokeratorefractometer and corneal topography keratometry readings decreased significantly from preoperatively to 1 month postoperatively (P<.01) but did not change significantly thereafter (P>.05). Preoperatively, the mean uncorrected (UDVA) and corrected (CDVA) distance visual acuities were 0.21 ± 0.08 and 0.73 ± 0.08, respectively; postoperatively, the means were 0.73 ± 0.10 and 0.98 ± 0.05, respectively. All eyes achieved a postoperative UDVA better than 0.5. No eye lost CDVA lines. The safety index was 1.34. The mean MRSE was -5.18 ± 1.74 D preoperatively and -1.05 ± 0.64 D postoperatively (P<.01). Postoperatively, 11 eyes (91.67%) were within ± 2.00 D of the SE, 8 (6.67%) were within ± 1.00 D, and 5 (41.67%) were within ± 0.50 D. No complications were encountered. CONCLUSION: Treatment of post-DALK keratoconus patients with LASIK to correct manifest refraction error seems to be a viable option.

The efficacy of topical interferon alpha 2b treatment in refractory vernal keratoconjunctivitis.

PURPOSE: This study aimed to investigate the efficacy and safety of a 2-month topical interferon alpha 2b treatment in patients with refractory vernal keratoconjunctivitis. METHODS: Twelve (10 male, 2 female) patients with refractory vernal keratoconjunctivitis received topical treatment with one million IU/mL interferon alpha 2b 4 times a day for 2 months. Symptom and ophthalmological examination scores were assessed at baseline and during follow-up. RESULTS: No significant complications or side effects associated with the use of topical interferon alpha 2b were observed. Symptom scores for itching, tearing, photophobia, and total symptom score, and objective scores for corneal lesion, hyperemia, chemosis, papillary hypertrophy, secretion, and total examination score significantly improved during the 2-month treatment. Improvements were maintained after discontinuation of the treatment for most parameters. CONCLUSIONS: Topical interferon alpha 2b treatment seems to offer a safe and effective alternative for the treatment of refractory vernal keratoconjunctivitis for a brief period.

Modified capsular tension ring implantation in eyes with traumatic cataract and loss of zonular support.

PURPOSE: To evaluate the outcomes of implantation of a Cionni modified capsular tension ring (CTR) and a posterior chamber intraocular lens (PC IOL) in patients with traumatic cataract and loss of zonular support. SETTING: Eye Clinic II, Haydarpasa Numune Education and Research Hospital, Istanbul, Turkey. DESIGN: Case series. METHODS: Eyes with traumatic cataract and loss of zonular support had phacoemulsification with implantation of a foldable IOL and a 1- or 2-eyelet modified CTR. Preoperative features, preoperative and postoperative corrected distance visual acuity (CDVA), intraoperative performance, IOL position, and complications were evaluated. RESULTS: The study enrolled 16 eyes (16 patients). The mean CDVA was 0.89 logMAR ± 0.41 (SD) preoperatively and 0.33 ± 0.43 logMAR at the last postoperative examination (P=.001). Postoperatively, the mean spherical equivalent was -0.23 diopter (D) (range -1.50 to +1.00 D) and the mean postoperative astigmatism, 1.59 D (range 0.50 to 4.00 D). Eight eyes (50.0%) had phacodonesis preoperatively; no eye had pseudophacodonesis postoperatively. Preoperatively, 10 eyes (62.5%) had symptomatic decentration. Two eyes (12.5%) had asymptomatic nonprogressive decentration in the early postoperative period; no eye had symptomatic decentration throughout the follow-up. Three eyes (18.8%) preoperatively and 1 eye (6.2%) postoperatively had vitreous in the anterior chamber. Four eyes (25.0%) required anterior vitrectomy. Other complications were symptomatic posterior capsule opacification in 8 eyes (50.0%) and transient increased intraocular pressure in 2 eyes (12.5%). CONCLUSION: The use of a modified CTR preserved the capsular bag and resulted in good PC IOL centration with few significant complications in patients with traumatic cataract and loss of zonular support. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Effects of contact lenses on the ocular surface in patients with keratoconus: piggyback versus ClearKone hybrid lenses.

OBJECTIVE: Because patients with keratoconus tend to wear contact lens for a long period of time, they are more prone to ocular surface changes induced by the lenses. This study aimed to compare immunohistochemical changes induced by two different types of contact lenses in patients with keratoconus. METHODS: Twenty-four contact lens-naive keratoconus patients (30 eyes) were included in this prospective study. Group 1 comprised 14 eyes (12 patients) wearing piggyback lenses, and group 2 comprised 16 eyes (12 patients) wearing ClearKone hybrid lenses. The patients were analyzed for bulbar conjunctival impression cytology, tear interleukin-6 (IL-6) and IL-8 levels, and confocal microscopic changes of the cornea before and 6 months after wearing contact lenses. RESULTS: Six months after wearing contact lenses, the groups demonstrated similar epithelial metaplasia rates, tear IL-6 and IL-8 levels, and similar confocal microscopy findings (P>0.05 for all intergroup comparisons). Among the parameters tested in this study, only IL-6 and IL-8 levels and posterior keratocyte density on confocal microscopy showed an increase after 6 months when compared with baseline values but at a similar degree in the two groups. CONCLUSIONS: This small sample was not able to demonstrate a difference between the two types of lenses with regard to the variables examined, and further larger trials would be required to determine if differences truly exist or not. However, clinicians may still consider patient comfort and vision in selecting the lens type in patients with keratoconus.