Sensitivity Change in Cornea and Tear Layer due to Incision Difference on Cataract Surgery with Either Manual Small-Incision Cataract Surgery or Phacoemulsification

Preoperative Treatment of Meibomian Gland Dysfunction with a Vectored Thermal Pulsation System Prior to Extended Depth of Focus IOL Implantation

INTRODUCTION

Patients implanted with a range-of-vision intraocular lens (IOL) (multifocal or extended depth of focus, EDOF) may be more susceptible to visual disturbances from poor tear film quality, and prophylactic treatment of meibomian gland dysfunction (MGD) has been recommended. The purpose was to evaluate whether vectored thermal pulsation (LipiFlow™) treatment prior to cataract surgery with a range-of-vision IOL safely improves postoperative outcomes.

METHODS

This is a prospective, randomized, open-label, crossover, multicenter study of patients with mild-to-moderate MGD and cataract. The test group underwent LipiFlow treatment prior to cataract surgery and implantation of an EDOF IOL, while the control group did not. Both groups were evaluated 3 months postoperatively, after which the control group received LipiFlow treatment (crossover). The control group was re-evaluated 4 months postoperatively.

RESULTS

A total of 121 subjects were randomized, with 117 eyes in the test group and 115 eyes in the control group. At 3 months after surgery, the test group had a significantly greater improvement from baseline in total meibomian gland score compared with the control group (P = 0.046). At 1 month after surgery, the test group had a significant decrease in corneal (P = 0.04) and conjunctival (P = 0.002) staining compared to the control group. At 3 months after surgery, the test group had significantly lower incidence of being bothered by halos compared with the control group (P = 0.019). The control group had a significantly lower incidence of being bothered by multiple or double vision compared with the test group (P = 0.016). After crossover, patients had significant improvement in vision (P = 0.03) and total meibomian gland score (P < 0.0001). No safety concerns or relevant safety findings were uncovered.

CONCLUSION

Presurgical LipiFlow treatment of patients implanted with range-of-vision IOLs improved meibomian gland function and postoperative ocular surface health. This supports guidelines recommending proactive diagnosis and management of MGD in patients with cataracts to improve patient experience.

TRIAL REGISTRATION

The study was registered on www.

CLINICALTRIALS

gov (NCT03708367).

Effects of cataract surgery on blinking

PURPOSE

To assess the effects of cataract surgery on the spontaneous blinking pattern and blinking kinematics.

SETTING

FISABIO Oftalmología Médica Eye Hospital, Valencia, Spain.

DESIGN

Observational descriptive clinical study.

METHOD

Patients with senile cataract were evaluated before (visit 1) and at 1 month (visit 2) and 3 months (visit 3) after undergoing phacoemulsification cataract surgery. The blinking of patients was recorded for 90 seconds using an eye-tracking device. Blinks were analyzed by means of image analysis to obtain a noninvasive detailed description of blinking including blink rate, number of complete and incomplete blinks, percentage of incomplete blinks, and kinematic parameters, including amplitude, closing, contact, opening, and total durations and closing and opening speeds.

RESULTS

50 patients were included in this study. The blink rate was significantly smaller at visit 3 compared with baseline ( P = .03) and visit 2 ( P = .001). Likewise, the number of complete blinks was significantly smaller, and the percentage of incomplete blinks was significantly higher at 3 months postoperatively compared with baseline ( P = .02 and P = .01, respectively), although no differences were observed at 1 month postoperatively ( P > .05). Conversely, no differences in the number of incomplete blinks or any kinematic parameter were observed between visits ( P = .12).

CONCLUSIONS

Cataract surgery significantly altered the blinking pattern at 3 months postoperatively, although kinematic parameters remained unvaried. Clinicians should be aware of potential alterations in blinking after phacoemulsification cataract surgery and the implications this may have on the ocular surface of patients.

Randomised, Single Blind, Controlled, Three-Month Clinical Trial on the Evaluation and Treatment of the Ocular Surface Damage Following Phacoemulsification

Background: To determine efficacy of two lacrimal substitutes on signs and symptoms of ocular surface disease after phacoemulsification; to determine impact of surgery on patients’ vision related quality of life. Monocentric, randomised, physician blinded, three parallel groups clinical trial. Design and Methods: Patients in the operative list for phacoemulsification have been screened for eligibility; they underwent (at time 0, 15, 45 and 90 days): slit lamp examination; tear film break-up time (BUT); corneal staining; tear volume; 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ); Ocular Surface Disease Index (OSDI). Treatments to be compared were: 1. standard of care-SOC (lomefloxacine and tobramicine/dexamethasone fixed combination 4 times a day for 2 weeks), 2. SOC + carboxymethylcellulose sodium 0.5% and glycerin 0.9%, 3. SOC + Sodium Hyaluronate 0.15%. Study treatment started at T15. Groups were compared with parametric or nonparametric tests, and with Pearson’s χ2 test. Correlation between continuous variables was assessed by means of Pearson’s or Spearman’s coefficient. Results: Fifty-three patients were enrolled. At 45 and at 90 days from surgery, the group receiving lacrimal substitutes presented better BUT and Schirmer I test (p = 0.009, <0.001, <0.001 and 0.001, respectively); dry eye presence showed significant difference by group at time 90 (p = 0.019). General vision, near activity and vision-specific dependency subscales improved after surgery (p = <0.001, 0.004 and 0.048, respectively). At 45 and 90 days from surgery, the OSDI score significantly changed (p < 0.001).Conclusions: Cataract surgery causes the onset or the worsening of dry eye. Use of artificial tears can significantly reduce symptoms and signs of dry eye in patients after phacoemulsification.

Alpha-Glycerylphosphorylcholine and D-Panthenol Eye Drops in Patients Undergoing Cataract Surgery

Cataract surgery is widespread. The surgical procedure is associated with damage to the epithelial barrier and interruption of the corneal innervation. In addition, pathological events sustain signs and symptoms that may persist for a long time. Recently, a fixed combination of alpha-glycerylphosphorylcholine and D-Panthenol (Oftassiale) has been available as eye drops. The present study investigated the effects of an Oftassiale therapy in 20 patients undergoing cataract surgery. A comparison group included 20 patients treated with topical hyaluronic acid. Standard prophylactic and anti-inflammatory treatment was prescribed to all patients. Clinical signs and symptoms were assessed over time. In vivo confocal microscopy (IVCM) was performed accordingly. Oftassiale treatment significantly reduced clinical features and improved IVCM outcomes. In addition, therapy was well-tolerated, and no clinically significant adverse events occurred. In conclusion, this study confirmed that IVCM helps assess the tunnel after cataract surgery due to its ability to provide microscopic details in vivo. Topical therapy with alpha-glycerylphosphorylcholine and D-Panthenol eye drops promoted and stabilized the reepithelialization process. This fixed combination also accelerated and modulated the repair of the corneal innervation. Moreover, this treatment was well-tolerated and safe.

The influence of congenital and developmental cataract surgery on the ocular surface in a six-month follow-up prospective clinical study

BACKGROUND

The purpose of this study was to identify changes in tear film function and meibomian gland function in children after congenital/developmental cataract surgery.

METHODS

This study enrolled 16 eyes of 16 congenital/developmental cataract patients (mean age: 8.05 ± 1.43 years) who underwent cataract surgery and 16 eyes of 16 normal volunteers (mean age: 8.31 ± 2.18 years). Clinical assessments were conducted preoperatively and at 1 week, 1, 3 and 6 months postoperatively. Symptom questionnaires, non-invasive tear film break-up time, tear meniscus height, corneal fluorescein staining, lid margin abnormality, meibomian gland expressibility, and meibography were assessed.

RESULTS

The ocular symptom score was significantly higher in congenital/developmental cataract patients compared to normal controls during the 5 visits (P = 0.009). And the average non-invasive tear film break-up time was significantly lower in congenital/developmental cataract patients compared to normal controls (P = 0.017). The first non-invasive tear film break-up time and average non-invasive tear film break-up time were lowest at 1 month postoperatively compared to baseline levels (P = 0.008 and P = 0.012, respectively). The lid margin score of the upper eyelid was significantly higher in congenital/developmental cataract patients compared to normal controls at 1 week postoperatively (P = 0.027). The meibum expressibility score decreased significantly during the 5 visits (P = 0.024). No significant difference was observed in meibomian gland tortuosity, meibomian gland width, meibomian gland area and meibomian gland length between the congenital/developmental group and normal controls preoperatively and at 6 months postoperatively (P > 0.05).

CONCLUSION

Tear film stability and meibomian gland function are worsened transiently after congenital/developmental cataract surgery without accompanying meibomian gland morphological changes.

The Incidence of Post Phacoemulsification Surgery Induced Dry Eye Disease in Upper Egypt

Background

Dry eye is described as a multifactorial disorder of the tear film that occurs due to excessive tear evaporation or tears insufficiency, and so leads to ocular discomfort sensation and ocular tissue damage with time.

Objective

To assess the incidence of dry eye disease after uncomplicated phacoemulsification surgery in patients with no pre-existed dry eye.

Patients and Methods

This hospital-based cross-sectional study was conducted to assess the incidence of dry eye at 100 eyes of 100 patients who underwent uncomplicated phacoemulsification surgery, with age more than 45 years old. It is measured by dry eye tests Schirmer 1 and tear break up time.

Results

This study showed that 22% of the patients who underwent uncomplicated phacoemulsification surgery suffered from dry eye with significant results at 1st week post-operative that improved over time.

Conclusion

There was a statistically significant drop in the results of the Schirmer test 1 and TBUT post phacoemulsification surgery, but with no clinical significance as they still at the normal range. The tear film assessment results at the 1st week post-operative were out of the normal range with TBUT and were borderline with ST1 in 22% of the patients. These results improved over time to return to the normal values within 12 weeks postoperatively.

Dry Eye Disease after Cataract Surgery: Study of its Determinants and Risk Factors

Objectives

To study the incidence of dry eye and its determinants in patients undergoing cataract surgery.

Materials and Methods

One hundred twenty patients with senile cataract underwent Schirmer's test, tear break-up time (TBUT) test, lissamine green staining of the cornea and conjunctiva, and Ocular Surface Disease Index (OSDI) for evaluation of dry eye preoperatively and again at first and second follow-up examinations at 1 week and 1 month after cataract surgery.

Results

Mean age of the patients was 59.25+9.77 years and 73 (60.8%) were men. None of the patients had dry eye at the time of enrollment as per the criteria of our study. Postoperatively, Schirmer's test values ranged from 12-35 mm and 8-24 mm at first and second follow-ups, respectively. Mean TBUT was 13.16±2.45 and 9.64±2.20 seconds, while lissamine green staining score was 3 in 67 (55.8%) and 1 in 67 (55.8%) subjects at first and second follow-up, respectively. OSDI values ranged from 1-30 and 10-33 with a mean of 25.97±5.34 and 11.96±7.47 respectively at first and second follow-up. At first follow-up, 89.1% of the 56 patients who underwent phacoemulsification were found to have grade 2 dry eye (p<0.001), while 92.2% of the 64 patients who underwent small-incision cataract surgery (SICS) had grade 2 dry eye (p<0.001). At second follow-up, grade 0 dry eye was observed in 92.2% of the patients who underwent phacoemulsification and 82.1% of the patients who underwent SICS (p<0.001).

Conclusion

The incidence of dry eye after cataract surgery was high and mostly independent of demographic and anthropometric profile, type of surgical procedure, time of microscope exposure, and amount of energy used. This dryness was transient in nature and showed a declining trend, tending to achieve normalization by the end of 1 month.

Relationship between ocular surface disease and patient's satisfaction among cataract surgical patients in Nigeria

PURPOSE

To determine the effect of clinical and cytological features of ocular surface disease on patient's satisfaction following small incision cataract surgery at a tertiary eye care centre.

METHOD

This is a prospective observational study of 70 consecutive consenting patients who underwent manual small incision cataract surgery(MSICS) at a tertiary eye care centre. All participants underwent ocular surface profile assessment using Schirmer I test (ST1), tear film break-up time (TBUT), conjunctival impression cytology (CIC) and ocular surface disease index (OSDI) at pre-operative visit, 1-week and 4-week post-operative visit. Patient's satisfaction with surgical outcome was evaluated at 6-week post-operative visit using a rating scale of 1 to 10. Data were analysed using IBM Statistical Package for the Social Sciences (SPSS) version 20.0 (IBM Corp., Armonk, NY USA).

RESULTS

The mean age was 68 ± 9.4 years with a male/female ratio of 1:1.1. The mean OSDI score decreased significantly (p < 0.001) from 33.1 ± 8.4 pre-operatively to 20.8 ± 7.4 four weeks after surgery. The TBUT was 12 ± 4.1 s pre-operatively, but significantly reduced to 11.2 ± 3.9 s (p < 0.001) at 4-week post-operative period. At 6 weeks, patients with normal CIC reduced from 53 (75.8%) pre-operatively to 8 (11.4%) (p < 0.001, z = - 7.24). Fifty percent of patients with severe post-operative ocular surface disease reported dissatisfaction with their surgical outcome (p = 0.024).

CONCLUSION

Manual small incision cataract surgery can significantly impair the ocular surface health profile of patients. The presence of ocular surface disease in patients pre-operatively can negatively impact their level of satisfaction with surgical outcome.

[Methods and clinical significance of the condition of corneal nerve fibers]

The review provides basic information about embryology, structural features, biochemical composition, functions and classification of corneal nerve fibers, and describes anatomical, histological and functional diagnostic techniques for corneal nerves. Each method for analyzing the structure of the nerve fiber, its advantages and disadvantages are described in detail, including the history of the development of confocal microscopy (laser and light) and esthesiometry (contact and non-contact). The article also presents the criteria according to which the structure of the nerve fiber is estimated using laser confocal microscopy, and the shortcomings of these criteria. Additionally, the article reports on the futility of the use of modern esthesiometry methods.

Preoperative Management of MGD with Vectored Thermal Pulsation before Cataract Surgery: A Prospective, Controlled Clinical Trial

Purpose: To investigate the efficacy of preoperative monocular treatment in elderly cataract patients with Meibomian Gland Dysfunction (MGD) utilizing vectored thermal pulsation treatment.Materials and Methods: This study was a prospective, examiner-masked contralateral eye clinical trial. Patients previously diagnosed with MGD undergoing uncomplicated cataract surgery in two eyes were enrolled. The eye perceived by the patient to be more symptomatic of MGD received a 12 min vectored thermal pulsation treatment using the LipiFlow Thermal Pulsation System, and was referred to as the LipiFlow-surgery eye. The contralateral eye then served as the nonLipiFlow-surgery eye. Patients with MGD not undergoing cataract surgery were enrolled as the control group. Within the control group, the eye that received LipiFlow treatment was considered the LipiFlow-nonsurgery eye, while the contralateral eye served as the nonLipiFlow-nonsurgery eye. All patients were examined before treatment and at one-week, one-month, and three-month intervals after treatment. Clinical parameters included dry eye symptoms, average lipid layer thickness (LLT-ave), tear breakup time (TBUT), corneal staining, Schirmer I tests, Meibomian glands yielding liquid secretion (MGYLS), and meibomian gland dropout.Results: A total of 32 patients (64 eyes) were examined during the three-month follow-up. There was a significant reduction in dry eye symptoms in non-surgery patients with monocular treatment of MGD, while no change in surgery patients was observed. Significant improvement of MGYLS in LipiFlow-surgery and LipiFlow-nonsurgery eyes during the follow-up time (p < .001) was reported, while no difference was observed in nonLipiFlow-surgery and nonLipiFlow-nonsurgery eyes. A statistically significant difference was seen in TBUT between LipiFlow-surgery and nonLipiFlow-surgery eyes at one-week and one-month intervals (p = .019 and 0.019, respectively). Differences in other clinical parameters were not statistically significant.Conclusions: Our findings suggest that although subjective symptoms were not alleviated, a single application of LipiFlow treatment before cataract surgery is effective in alleviating blockage of meibomian glands and preventing the decline of TBUT after cataract surgery.

Efficacy of bandage contact lens for the management of dry eye disease after cataract surgery

Purpose

We aimed to evaluate the efficacy of bandage contact lens (BCL) for the management of dry eye disease (DED) after cataract surgery.

Methods

A total of 120 patients (140 eyes) with age-related cataract and DED were enrolled in this study. Patients underwent standard micro-incision phacoemulsification surgeries and were divided into control or BCL groups. Slit-lamp biomicroscopic examination, Ocular Surface Disease Index, keratograph analysis and Schirmer I test were executed, and the levels of tear inflammatory molecules were detected.

Results

In the control group, the NIAvg-BUT and Schirmer I test scores were significantly decreased at 1 week post-operation compared with baseline levels (P = 0.035 and P = 0.009, respectively). In the BCL group, the NIF-BUT and Schemer I test scores were significantly improved at 1 month after operation compared with the control group (P = 0.012 and P < 0.001, respectively). Levels of IL-6, IL-8 and ICAM-1 were significantly increased in the control group at 1 month after the operation (P = 0.005, P = 0.038 and P = 0.022, respectively), while there was no difference in the BCL group. The increase in the IL-6 level in the control group was significantly higher compared with that in the BCL group (P = 0.047). In DED patients, there were significant correlations between ocular surface parameters and inflammatory molecules.

Conclusions

Cataract surgery could lead to the development or worsening of DED. The application of BCLs after cataract surgery could stabilize the ocular surface and tear film, improve the corneal healing and reduce the inflammation. Collectively, our findings suggested that proper use of BCLs after cataract surgery played an effective role in the management of DED.

Trial registration

ClinicalTrials, NCT04100031. Registered 18 September 2019—retrospectively registered

Protecting the Ocular Surface at the Time of Cataract Surgery: Intracameral Mydriatic and Anaesthetic Combination Versus A Standard Topical Protocol

Introduction

An intracameral mydriatic and anaesthetic combination has been approved for injection into the anterior chamber in order to provide rapid and stable mydriasis and sustained intraocular anaesthesia during cataract surgery.

Methods

In this prospective study, conducted at the Eye Clinic, University of Florence, Italy, we compared phacoemulsification using the standard mydriatic-anaesthetic eye-drop protocol with that using the standard protocol in terms of corneal changes, ocular surface parameters and visual quality. Sixty patients (60 eyes) were included in the study, with 30 eyes receiving Mydrane®, a novel injectable intracameral solution, during phacoemulsification (Mydrane protocol, MP) and 30 eyes receiving the standard mydriatic-anaesthetic eye drops (standard protocol, SP). The following parameters were assessed using in vivo confocal microscopy (IVCM): central corneal thickness (CCT); flare and cells in the aqueous humor (Flare); keratocyte activation (KA), Langerhans’ cell density (LCD), nerve fibre density (NFD) and endothelial cell density (ECD). The Ocular Surface Disease Index (OSDI) score, tear breakup time (TBUT) and Schirmer’s test I (STI) were also evaluated. The Optical Scattering Index (OSI) and its standard deviation (OSI-SD) were assessed using the Optical Quality Analysing System (Visiometrics SL, Terrassa, Spain).

Results

In the MP group, CCT, Flare, KA and LCD values returned to baseline values within 15 postoperative days. The mean ECD and NFD decreased significantly in both groups from baseline at all follow-up assessments, with no statistically significant difference between groups. TBUT returned to the preoperative level at postoperative day 15 in the MP group. OSDI scores and STI were significantly worse in both groups at all follow-up assessments compared to baseline. At postoperative day 15 OSI and OSI-SD values were significantly better in the MP group than in the SP group.

Conclusions

The use of Mydrane during cataract surgery showed a good safety profile and few toxic side effects, ensuring better optical quality and tear film stability.

[Changes in corneal nerve fibers after microinvasive cataract surgery (a preliminary report)]

INTRODUCTION

Potential changes in corneal nerve fibers (CNF) induced by cataract phacoemulsification remain insufficiently studied. The need for research in this direction is dictated by a number of circumstances: introduction of corneal confocal microscopy into clinical practice, the need for phaco surgery in the presence of corneal changes of various genesis, the possible negative impact of laser radiation during hybrid (femtosecond laser-assisted) phacoemulsification.

PURPOSE

To assess the changes in CNF after various methods of microinvasive cataract surgery.

MATERIAL AND METHODS

The studies were conducted in patients aged 50 to 60 years who underwent standard ultrasound and hybrid phacoemulsification; the patients were respectively divided into two groups (30 surgeries each). The algorithm for assessing the state of CNF involved laser confocal microscopy using original software. To quantify the state of the nerves, two coefficients were used: CNF orientation anisotropy (KΔL) and CNF orientation symmetry (K_sym).

RESULTS

Regardless of the surgery technique, tendencies were noted for the orientation anisotropy coefficient to decrease and the orientation symmetry coefficient to increase, which are conditionally comparable with previously identified age-related changes in CNF. After hybrid phacoemulsification, a decrease in the orientation anisotropy coefficient 2-2.5 months after the intervention turned out to be statistically less significant compared to the standard ultrasound technique.

CONCLUSION

Further research should be aimed at analyzing the long-term results of both microinvasive phacosurgery techniques and the «classical» extracapsular cataract extraction, which remains the method of choice in a number of clinical situations.

[Phacosurgery effects on the condition of corneal nerve fibers]

The question of potential changes in the nerve fibers of the cornea induced by phacosurgery remains poorly investigated. This is a review of results of many individual studies aimed at assessing the condition of corneal nerve fibers following different techniques of cataract removal. The authors substantiate the necessity for structural analysis of fiber changes based on in vivo confocal microscopy of the cornea. Functional assessment of corneal sensitivity (esthesiometry) does not allow objective conclusions, for several reasons. Further studies on corneal nerve changes after phacosurgery could be directed at improving software products for objective quantitative assessment of corneal nerve fibers and analyzing long-term results of various phacosurgery techniques.

Presbyopia and the aging eye: Existing refractive approaches and their potential impact on dry eye signs and symptoms

Every part of the human body is subject to aging, including the eye. An increased prevalence of dry eye disease with age is widely acknowledged. Aging threatens ocular surface homeostasis, altering the normal functioning of the lacrimal functional unit and potentially leading to signs and symptoms of dry eye. Additional age-related processes take place within the crystalline lens, leading to presbyopia and cataractogenesis. Correction strategies for presbyopia and cataracts may directly or indirectly challenge the ocular surface. Contact lenses disturb the normal structure of the tear film and can interact negatively with the ocular surface, further deteriorating an already unbalanced tear film in presbyopes, however, newer contact lens designs can overcome some of these issues. Moreover, cataract and corneal refractive surgeries sever corneal nerves and disrupt the corneal epithelium and ocular surface, which can influence surgical outcomes and aggravate dryness symptoms in older age groups. This review summarises the current understanding of how the invasive nature of contact lens wear and cataract and refractive surgery influence signs and symptoms of ocular dryness in an aging population.

Impact of 0.1% sodium hyaluronate and 0.2% sodium hyaluronate artificial tears on postoperative discomfort following cataract extraction surgery: a comparative study

Background

Recent artificial tear preparations have provided 0.2% concentration of sodium hyaluronate. However, no published data exist on their potential superiority against 0.1% in alleviating dry-eye-disease symptoms in cataract extraction surgery.

Methods

A total of 180 patients that underwent cataract extraction surgery were randomly divided into 2 groups according to their postoperative regime: Study group (SG) received fixed combination of tobramycin and dexamethasone (FCTD) quid for 3 weeks, and additionally 0.2% sodium hyaluronate provided in the COMOD® device quid for 6 weeks. Control group (CG) received fixed combination of tobramycin and dexamethasone (FCTD) quid for 3 weeks, and additionally 0.1% sodium hyaluronate provided in the COMOD® device quid for 6 weeks. The following indexes were evaluated at 3 postoperative checkpoints: 1) Surface discomfort index (SDI) which was derived by four direct 10-scale Likert-type questions that were addressed to the patient and pertained to: a) foreign body sensation (FBS), b) blinking discomfort (BD), c) stinging sensation (SS), d) tearing sensation (TS), 2) Tear break-up time (TBUT), 3) Schirmer’s test, 4) Central corneal thickness (CCT), and 4) Central Corneal Sensitivity (CCS).

Results

Both groups showed reduced CCS values at all postoperative examination points; however, SG participants had significantly better CCS (all p < 0.05). SG had better TBUT than CG at the 3rd (p = 0.03) and 6th examination points (p = 0.04). Moreover, SG had better SDI scores at the 3rd (SDI = 9.26 ± 0.55) and 6th weeks (SDI = 9.47 ± 0.48) vs. CG participants (p = 0.03 and p < 0.01, respectively).

Conclusion

The increased 0.2% sodium hyaluronate concentration in the artificial tears provided in the COMOD® device seems to address dry-eye-disease symptoms better in patients who underwent phacoemulsification surgery than the 0.1% concentration.

Trial registration

ClinicalTrials.govIdentifier:NCT03705949 Oct 15, 2018, retrospectively registered.

Dry eye disease and oxidative stress

Dry eye, an age-related condition, is a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance and tear film instability. Environmental factors are also often implicated in dry eye including exposure to pollutants, ultraviolet (UV) radiation and ozone as well as the chronic use of preserved eyedrops such as in the treatment of glaucoma. These factors increase oxidative stress and ocular surface inflammation. Here, we reviewed the cellular, animal and clinical studies that point to the role of oxidative stress in dry eye disease. The biomarkers used to indicate oxidative damage in ocular surface tissues include 8-hydroxy-2 deoxyguanosine (8-OHdG), 4-hydroxynonenal (HNE) and malondialdehyde (MDD). Antioxidative defences in the ocular surface occur in the form of tear proteins such as lactoferrin and S100A proteins, and enzymes such as superoxide dismutase (SOD), peroxidase, catalase and mitochondrial oxidative enzymes. An imbalance between the level of reactive oxygen species (ROS) and the action of protective enzymes will lead to oxidative damage, and possibly inflammation. A small number of interventional studies suggest that oxidative stress may be directly targeted in topical therapy of dry eye treatment. For example, in vitro studies suggest that L-carnitine and pterostilbene, a blueberry component may reduce oxidative stress, and in animal studies, alpha-lipoic acid (ALP) and selenoprotein P may be helpful. Examples of treatments used in clinical trials include vitamin B12 eyedrops and iodide iontophoresis. With recent emphasis on ageing medicine and preventive holistic health, as well as the role of environmental science, research on oxidative stress in the ocular surface is likely to have increasing impact in the coming years.

Influence of glaucoma surgery on the ocular surface using oculus keratograph

PURPOSE

To investigate the influence of trabeculectomy and phacotrabeculectomy on the ocular surface.

DESIGN

Retrospective, case-control study.

METHODS

Eighty-one samples without dry eyes were recruited and divided into three groups, including phacoemulsification group (N = 30) as control group, trabeculectomy group (N = 27) and phacotrabeculectomy group (N = 24) as study groups. Ocular surface parameters, including noninvasive keratograph first (NifBUT) and average (NiaBUT) tear film breakup time, tear meniscus height (TMH) and corneal fluorescein stain (CFS), were estimated preoperatively, at 3 days, 1 month and 3 months postoperatively using oculus keratograph.

RESULTS

No significant difference was observed in ocular surface parameters at baseline among three groups (p > 0.05). The magnitude of NifBUT and NiaBUT was reduced at 3 days and 1 month postoperatively in phacotrabeculectomy group, but greater than that in the other two groups (All p < 0.001). In all the groups, both the NifBUT and NiaBUT tended to recover at 1 and 3 months postoperatively, whereas both of them did not recover to baseline at 3 months postoperatively in trabeculectomy (NifBUT, p = 0.001; NiaBUT, p < 0.001) and phacotrabeculectomy group (NifBUT, p < 0.001; NiaBUT, p = 0.020). TMH was raised at 3 days postoperatively and restored to the baseline level at 1 and 3 months postoperatively for three groups (p > 0.05). CFS was elevated at 3 days postoperatively and different in recovery at 1 and 3 months postoperatively for three groups.

CONCLUSIONS

The influence of phacotrabeculectomy on ocular surface is worse than that of trabeculectomy for the short run and is not distinct different for a long time.

Long-term impact of dry eye symptoms on vision-related quality of life after phacoemulsification surgery

PURPOSE

To observe the long-term changes in dry eye symptoms and vision-related quality of life in age-related cataract patients after phacoemulsification.

METHODS

A total of 101 cataract patients after phacoemulsification combined with IOL implantation (Ph-IOL) in one eye were enrolled. Visual acuity, tear film breakup time (BUT), and Schirmer test 1 (ST1) were measured before and 1, 3, and 6 months after surgery. Ocular Surface Disease Index (OSDI) scores were used to evaluate the severity of dry eye symptoms. Utility values were assessed by the time trade-off (TTO), standard gamble for death (SGD), standard gamble for blindness (SGB) and rating scale (RS).

RESULTS

The average LogMAR visual acuity in the operated eye was 1.35 ± 0.50 and increased rapidly after Ph-IOL, approaching a peak at 3 months (0.26 ± 0.15). The BUT and ST1 results decreased abruptly 1 month after surgery and gradually recovered until 6 months. OSDI scores increased significantly after surgery and gradually decreased until 6 months. Utility values evaluated by TTO, SGD, SGB and RS before surgery were 0.67 ± 0.19, 0.75 ± 0.15, 0.67 ± 0.20 and 0.2 ± 0.18, respectively, and increased to 0.91 ± 0.06, 0.98 ± 0.04, 0.92 ± 0.52 and 0.91 ± 0.06, 6 months after. Utility values measured with TTO, SGB or RS correlated significantly (P < 0.05) with visual acuity and OSDI scores pre- and postoperatively.

CONCLUSIONS

Dry eye symptoms persist more than 3 months after Ph-IOL. Utility values were negatively influenced by dry eye symptoms.

The improvement of dry eye after cataract surgery by intraoperative using ophthalmic viscosurgical devices on the surface of cornea: The results of a consort-compliant randomized controlled trial

BACKGROUD

This study aimed to investigate the protective effect of intraoperative used hydroxypropyl methylcellulose (HPMC 2%) on the ocular surface after cataract surgery.

METHODS

A total of 149 eyes (149 patients) diagnosed with age-related cataract, age 69.19 ± 9.74 years, were enrolled in this prospective, parallel-design, continuous, randomised controlled study. Patients were randomly assigned to receive HPMC 2% (study group) or balanced salt solution (control group) during the surgery to moisturize the cornea surface. The Ocular Surface Disease Index, Schirmer test without topical anesthetics, tear break-up time, and corneal fluorescein staining were assessed preoperatively, 1 day, 1 week, and 1 month after the surgery, respectively.

RESULTS

The Schirmer test value of male patients in the study group at 1 week postoperation was higher than that of male patients in the control group (P = .019). For patients diagnosed with dry eye before the surgery, Schirmer test value in the male patients in the study group at 1 month after surgery was higher than that in the male patients in the control group (P = .037). Furthermore, for the cluster of preoperative dry eye patients whose surgical time was longer than median, corneal fluorescein staining of the patients in the study group was superior to that of the patients in the control group (P = .032).

CONCLUSION

Intraoperative use of HPMC 2% on the cornea surface could improve clinical outcomes of tear film and ocular surface health to some degree, especially in the patients diagnosed with dry eye before the surgery, male patients, and patients whose surgical time was relatively longer.

TFOS DEWS II iatrogenic report

Dry eye can be caused by a variety of iatrogenic interventions. The increasing number of patients looking for eye care or cosmetic procedures involving the eyes, together with a better understanding of the pathophysiological mechanisms of dry eye disease (DED), have led to the need for a specific report about iatrogenic dry eye within the TFOS DEWS II. Topical medications can cause DED due to their allergic, toxic and immuno-inflammatory effects on the ocular surface. Preservatives, such as benzalkonium chloride, may further aggravate DED. A variety of systemic drugs can also induce DED secondary to multiple mechanisms. Moreover, the use of contact lens induces or is associated with DED. However, one of the most emblematic situations is DED caused by surgical procedures such as corneal refractive surgery as in laser-assisted in situ keratomileusis (LASIK) and keratoplasty due to mechanisms intrinsic to the procedure (i.e. corneal nerve cutting) or even by the use of postoperative topical drugs. Cataract surgery, lid surgeries, botulinum toxin application and cosmetic procedures are also considered risk factors to iatrogenic DED, which can cause patient dissatisfaction, visual disturbance and poor surgical outcomes. This report also presents future directions to address iatrogenic DED, including the need for more in-depth epidemiological studies about the risk factors, development of less toxic medications and preservatives, as well as new techniques for less invasive eye surgeries. Novel research into detection of early dry eye prior to surgeries, efforts to establish appropriate therapeutics and a greater attempt to regulate and oversee medications, preservatives and procedures should be considered.

Impact of polyethylene glycol 400/propylene glycol/hydroxypropyl-guar and 0.1% sodium hyaluronate on postoperative discomfort following cataract extraction surgery: a comparative study

Background

Universal postoperative guidelines for cataract extraction surgery are yet to be introduced. Artificial tears are gaining popularity as an additional integral component of the postoperative regime. The primary objective of this study was to explore the impact of two prevalent artificial tear preparations on postoperative discomfort following cataract extraction surgery.

Methods

A total of 180 patients that underwent cataract extraction surgery were randomly divided into three groups according to their postoperative regime: a) Study group 1 (SG1) received a fixed combination of tobramycin and dexamethasone (FCTD) quid for 3 weeks and, additionally polyethylene glycol 400/propylene glycol/hydroxypropyl-guar quid, for 6 weeks, b) Study group 2 (SG2) received FCTD quid for 3 weeks and, additionally 0.1% sodium hyaluronate provided in the COMOD® device quid, for 6 weeks, and, c) Control Group (CG) received only FCTD quid for 3 weeks. The following indexes were evaluated at three postoperative checkpoints: 1) Subjective discomfort index (SDI) derived from four direct 10-scale Likert-type questions that were addressed to the patient and pertained to: a) foreign body sensation (FBS), b) blinking discomfort (BD), c) stinging sensation (SS), d) tearing sensation (TS), 2) Tear break-up time (TBUT), 3) Central corneal thickness (CCT) and, 4) Central Corneal Sensitivity (CCS).

Results

Both groups showed increased CCT values at the first examination point and reduced CCS values at all examination points. Furthermore, both SGs had better TBUT times at all examination points compared to CG (CG: 8.86 ± 1.08, SG1: 9.59 ± 1.45, CG2: 9.45 ± 1.33, p < 0.05). BD was significantly better in both SGs only at the 1^st week of examination, while SDI values were better until the 3^rd week and only borderline better at 6^th week. Lastly, no significant differences were detected between SGs, regarding all parameters, at all examination points.

Conclusion

Polyethylene glycol 400/propylene glycol/hydroxypropyl-guar and 0.1% sodium hyaluronate provided in the COMOD® device seem to be equally efficient in alleviating OSD symptoms following cataract extraction surgery and any of them should be routinely added to the postoperative regime.

Trial registration

ClinicalTrials.gov Identifier: https://clinicaltrials.gov/ct2/show/NCT02558218NCT02558218

Electronic supplementary material

The online version of this article (doi:10.1186/s40662-017-0079-5) contains supplementary material, which is available to authorized users.

Evaluation of dry eye after femtosecond laser-assisted cataract surgery

PURPOSE

To compare dry-eye signs and symptoms after femtosecond laser-assisted cataract surgery and conventional phacoemulsification.

SETTING

Eye Center of the 2nd Affiliated Hospital, Medical College of Zhejiang University, Hangzhou, China.

DESIGN

Prospective consecutive nonrandomized comparative cohort study.

METHODS

Consecutive patients who had femtosecond laser-assisted or phacoemulsification cataract surgery were assessed. Dry-eye markers including the ocular surface disease index (OSDI) and subjective symptom questionnaire, tear-film assessment using Keratograph 4 corneal topography, Schirmer testing I, and fluorescein staining were sequentially evaluated preoperatively and postoperatively at 1 day, 1 week, and 1 month.

RESULTS

The study recruited 137 eyes (137 patients) with similar baseline characteristics. Most patients developed dry eye postoperatively. Subjective symptoms and fluorescein staining scores elevated from baseline, tear breakup time and Schirmer testing I values decreased postoperatively, which peaked at 1 week and did not return to baseline within 1 month. There were no significant differences between the 2 groups (all P > .05) except for a higher fluorescein staining score in the femtosecond group at 1 day (P = .001), 1 week (P = .047), and 1 month (P = .025). OSDI score and subjective symptoms were greater in the laser group at 1 week (P = .014 and P = .016, respectively). Subgroup analysis showed obvious worsening by fluorescein staining at 1 day (P = .016) and 1 month (P = .009) in preoperative dry-eye patients.

CONCLUSIONS

Both methods worsened dry eye postoperatively. Femtosecond-assisted surgery had a higher risk for staining and dry-eye symptoms. Patients with preexisting dry eye who had femtosecond-assisted surgery had more severe ocular surface staining than those having conventional surgery.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Effects of 3% diquafosol sodium ophthalmic solution on higher-order aberrations in patients diagnosed with dry eye after cataract surgery

Purpose

To evaluate the effects of diquafosol sodium ophthalmic solution 3% (DQS) and artificial tears (AT) on higher-order aberrations (HOAs) in patients with dry eye after cataract surgery.

Design

This was a post hoc analysis of a previously conducted randomized clinical study.

Methods

Fifty-nine eyes from 42 patients (17 males and 25 females, aged 72.6±8.0 years) with verified or suspected dry eye at 4 weeks after cataract surgery were evaluated. The dry eye patients were randomly assigned to receive DQS or AT for 4 weeks. Tear breakup time (BUT), corneal and conjunctival fluorescein staining scores, and HOAs were analyzed before and after instillation. HOAs were measured consecutively for 10 seconds with a wavefront analyzer. Average HOAs, HOA fluctuations (fluctuation index [FI]) and changes in HOAs (stability index [SI]) were compared within and between the two groups.

Results

After 4 weeks of instillation, BUT significantly increased (P=0.001) compared with preinstillation values in the DQS group, but not in the AT group. This increase in BUT in the DQS group was significantly greater than in the AT group (P=0.014). Corneal and conjunctival fluorescein staining scores after instillation significantly improved compared with preinstillation values in the DQS group (P=0.018). In HOAs, the cornea aberration changed from an upward curve (a sawtooth pattern) to an almost constant value (a stable pattern) in the DQS group, but not in the AT group. In FI and SI, there were no significant changes in either group; however, FI and SI were significantly lower in the DQS group than in the AT group (both, P=0.004).

Conclusion

The dry eye patients after cataract surgery had a visual dysfunction in HOAs. DQS is effective to treat dry eye disease after cataract surgery with improvement of visual function.

Trehalose efficacy in dry eye syndrome treatment after phacoemulsification

Purpose to estimate the efficacy of “artificial tear” preparation on the trehalose base in dry eye syndrome treatment in cataract patients after phacoemulsification.Materials and methods: in 40 patients with incipient cataract phacoemulsification with IOL implantation was performed. During 1 week, all patients received eye gel with dexpanthenol in addition to postoperative therapy. Then, all patients were divided into two groups (randomization using envelopes): in the main group, the gel was replaced by Thealoz®, in the control group, the gel was discontinued. Special investigation tests (OSDI score, TBUT test, conjunctival hyperemia, corneal confocal tomography) were performed before surgery, in one week and one month after it. Statistical analysis was performed using SAS 9.4 program.Results: all investigated parameters had significant differences with time and between groups (р < 0.001). TBUT test result decreased in one week after surgery from 7.4 ± 2.1 to 4.6 ± 1.9 sec in the main group and from 7.5 ± 2.3 to 4.4 ± 2 sec in the control group. Return to baseline results in the control group was slowed down and made 6.4 ± 2.8 sec (compared with 7.9 ± 2.4 sec in the main one). In the trehalose group, OSDI score ameliorated from 35.1 ± 8.7 (in one week) to 14.2 ± 5.3 (in one month), in the control group, from 40.1 ± 11.5 to 24.8 ± 9. Conjunctival hyperemia was also less pronounced in the main group in one month after surgery: 0.45 ± 0.6 (1.6 ± 0.7 in one week), in the control group, these indices were equal to 1.7 ± 0.5 (in one week) and 1.3 ± 0.7 (in one month).Conclusions: Thealoz® use as a part of combined postoperative therapy helps to effectively fight against dry eye syndrome main signs and enhances treatment tolerance.

Mechanisms and management of dry eye in cataract surgery patients

PURPOSE OF REVIEW

To provide a summary of the mechanisms that may cause dry eye after cataract surgery and discuss available and upcoming treatment modalities.

RECENT FINDINGS

Development or worsening of dry eye symptoms after cataract surgery is multifactorial with corneal nerve transection, inflammation, goblet cell loss, and meibomian gland dysfunction commonly cited as underlying disorders. With increasing awareness of the prevalence of dry eye disease, current surgical techniques are being analyzed for their contribution to the issue. Although many classic interventions, such as artificial tears and anti-inflammatory drops, remain first-line treatment options, they may not adequately address abnormalities of the tear film. The trend has been to create new drugs and technologies that target meibomian gland deficiencies and restore goblet cell numbers.

SUMMARY

Therapy for postoperative dry eye symptoms should be determined based on symptom severity and which underlying cause is most prominent at a given time. Patients with high-level risk factors for dry eye should be evaluated preoperatively to determine whether they have preexisting dry eye disease or if they are susceptible to developing disease after surgery.

Outcomes of phacoemulsification in patients with chronic ocular graft-versus-host disease

PURPOSE

The purpose of this study was to evaluate the outcomes of phacoemulsification in patients with ocular graft-versus-host disease (GVHD).

METHODS

The occurrence of cataracts, cataract surgery, and its outcomes were analyzed in the medical records of 229 patients (458 eyes) with ocular GVHD. Outcome measures included pre- and postoperative corrected distance visual acuity (CDVA) and the rate of postoperative complications.

RESULTS

Of the 458 eyes evaluated, 58 were pseudophakic; from the 400 phakic eyes, 238 (59 %) presented with cataracts and 62 (26 %) underwent cataract surgery. Analysis of postoperative complications and visual outcomes at 1 month was performed in 51 eyes in which detailed surgical and immediate postoperative records were available. Preoperatively, the mean CDVA was 0.67 ± 0.57 LogMAR (Snellen 20/93), improving postoperatively to 0.17 ± 0.18 (Snellen 20/29) at 1 month (P < 0.0001), and to 0.13 ± 0.14 (Snellen 20/26) by the final follow-up visit (P < 0.0001). Postoperative complications included corneal epithelial defects (8 %), filamentary keratitis (6 %), worsening of corneal epitheliopathy (16 %), posterior capsular opacification (18 %), and cystoid macular edema (4 %). A corrected distance visual acuity of 20/30 or better was achieved in 87 % of the eyes; suboptimal CDVA improvement was attributable to severe ocular surface disease, pre-existing advanced glaucoma, and prior macular surgery.

CONCLUSIONS

Phacoemulsification in patients with chronic ocular GVHD is a safe and efficacious procedure resulting in significant visual improvement. Overall, postoperative adverse events responded well to timely management.

Comparison of treatment with preservative-free versus preserved sodium hyaluronate 0.1% and fluorometholone 0.1% eyedrops after cataract surgery in patients with preexisting dry-eye syndrome

PURPOSE

To compare treatment with preservative-free and preserved sodium hyaluronate 0.1% and fluorometholone 0.1% eyedrops after cataract surgery in patients with preexisting dry-eye syndrome.

SETTING

Bucheon St. Mary's Hospital, Catholic University of Korea, Seoul, Korea.

DESIGN

Randomized controlled study.

METHODS

Patients with cataract and dry-eye syndrome were randomly divided into 2 groups. Group 1 patients were treated with preservative-free sodium hyaluronate 0.1% and preservative-free fluorometholone 0.1% eyedrops 4 times a day in the first month and twice a day in the second month. Group 2 patients were treated with preserved eyedrops using the same schedule. Ocular Surface Disease Index (OSDI) score, tear-film breakup time (TBUT), Schirmer I test, corneal fluorescein staining, impression cytology, and antioxidant and inflammatory cytokine activities in tears were evaluated.

RESULTS

Both groups comprised 40 patients. At 2 months, the OSDI score, TBUT, Schirmer I score, fluorescein staining score, impression cytology findings, and goblet cell count were significantly better in Group 1 than in Group 2 (P<.05). The interleukin-1β and tumor necrosis factor-α concentrations were significantly less in the tears of Group 1 patients than in the tears of Group 2 patients, and catalase and superoxide dismutase 2 fluorescence intensities were significantly greater in the tears of Group 1 patients than in the tears of Group 2 patients (P<.05).

CONCLUSIONS

Preservative-free sodium hyaluronate 0.1% and fluorometholone 0.1% eyedrops can improve the symptoms and signs of dry-eye syndrome after cataract surgery. Preservative-free fluorometholone eyedrops may have antiinflammatory and antioxidant effects in tears of patients with dry-eye syndrome.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Effects of vitamin B12 on the corneal nerve regeneration in rats

The study was designed to investigate the effects of a new ophthalmic solution containing 0.05% vitamin B12 0.05% on corneal nerve regeneration in rats after corneal injury. Eyes of anesthetized male Wistar rats were subjected to corneal injury by removing the corneal epithelium with corneal brush (Algerbrush). After the epithelial debridement, the right eye of each animal received the instillation of one drop of the ophthalmic solution containing vitamin B12 0.05% plus taurine 0.5% and sodium hyaluronate 0.5% four time per day for 10 or 30 days. Left eyes were used as control and treated with solution containing taurine 0.5% and sodium hyaluronate 0.5% alone following the same regimen. Fluorescein staining by slit-lamp and morphological analysis was used to determine corneal wound healing. Immunohistochemistry, immunoblot and confocal microscopy were used to examine corneal re-innervation. Slit-lamp and histological analyses showed that re-epithelization of the corneas was accelerated in rats treated with vitamin B12. A clear-cut difference between the two groups of rats was seen after 10 days of treatment, whereas a near-to-complete re-epithelization was observed in both groups at 30 days. Vitamin B12 treatment had also a remarkable effect on corneal re-innervation, as shown by substantial increased in the expression of neurofilament 160 and β-III tubulin at both 10 and 30 days. The presence of SV2A-positive nerve endings suggests the presence of synapse-like specialized structures in corneal epithelium of the eye treated with vitamin B12. Our findings suggest that vitamin B12 treatment represents a powerful strategy to accelerate not only re-epithelization but also corneal re-innervation after mechanical injury.

Incidence and pattern of dry eye after cataract surgery

PURPOSE

To evaluate the incidence and severity pattern of dry eye after phacoemulsification.

SETTING

King Chulalongkorn Memorial Hospital, Bangkok, Thailand.

DESIGN

Prospective descriptive study.

METHODS

Samples were collected from ninety-two uncomplicated cataract patients who were 18 years old or older. Dry eye incidence and pattern were analyzed at days 0, 7, 30 and 90 after phacoemulsification using (1) Ocular Surface Disease Index (OSDI) questionnaire, (2) tear break up time (TBUT), (3) Oxford ocular surface staining system, and (4) Schirmer I test without anesthesia.

RESULTS

Seven days after phacoemulsification, the incidence of dry eye was 9.8% (95% confidence interval; 3.6-16.0%). The severity of dry eye peaked seven days post-phacoemulsification and was measured by OSDI questionnaire and all three clinical tests. Within thirty days and 3 months post-surgery, both the symptoms and signs showed rapid and gradual improvements, respectively. However, dry eye post-phacoemulsification was not significantly associated with sex and systemic hypertension (P = 0.26, 0.17 and 0.73, respectively).

CONCLUSIONS

The incidence of dry eye after phacoemulsification was 9.8%. Symptoms and signs of dry eye occurred as early as seven days post-phacoemulsification and the severity pattern improved over time. We recommend that ophthalmologists should evaluate patients both before and after phacoemulsification to prevent further damage to the ocular surface and able to manage the patient promptly and effectively so the patient will not have a poor quality of life and vision due to dry eye syndrome.

Confocal microscopic evaluation of cornea after AquaLase liquefaction cataract extraction

AIM

The most recent and innovative AquaLase liquefaction technology has offered an alternative to lens extraction. Many studies have investigated its functions and advantages. This article focuses on evaluating the in vivo microscopic cornea changes after AquaLase liquefaction by using a laser confocal microscope.

METHODS

In this perspective, randomized case study, 37 eyes of 35 patients submitted to cataract surgery were chosen to undergo AquaLase liquefaction cataract extraction. Each patient was assessed before the operation, on the 1(st), 7(th), and 30(th) postoperative days, and 6 months after the cataract extraction. The morphologies and quantitative comparisons of corneal cells and corneal nerves layer by layer were evaluated in vivo with the Heidelberg Retina Tomograph III-Rostock Cornea Module (HRT-III RCM) confocal microscope. ANOVA and Post-Hoc Bonferroni test were carried out to compare the results pre- and post-operation.

RESULTS

ANOVA results indicated no post-operation changes for epithelium and anterior stroma cells. Irregular segments of sub-basal nerve fiber were most pronounced seven days post-operation. In the mid and posterior stroma, keratocytes were obvious compared with the preoperative condition. Corneal endothelium cells became obviously swollen in cytoplasm and nucleus. The mid and posterior stroma cell density decreased from the 1(st) to 7(th) postoperative days (P<0.05). The corneal endothelium cell density decreased (P<0.05) and did not revert to the preoperative level after six months (P<0.05).

CONCLUSION

Slight microstructural abnormalities were identified in the corneal recovery process after AquaLase liquefaction. AquaLase liquefaction cataract extraction is safe for cornea.

In vivo confocal microscopy of corneal small fiber damage in diabetes mellitus

BACKGROUND

Advanced diabetic keratopathy includes impaired corneal sensation, reduced tear secretion, conjunctival squamous metaplasia, and goblet cell loss, as well as susceptibility to corneal erosions and ulcerations. It is thought to be a form of generalized diabetic neuropathy. Early diagnosis of nerve fiber degeneration is essential to prevent further damage.

METHODS

We examined the corneal innervation pattern of patients with diabetes mellitus type 1 and 2 of various durations by in vivo confocal microscopy, and correlated our findings to the severity of diabetic retinopathy, corneal sensation, peripheral diabetic neuropathy in the lower limb, and nephropathy.

RESULTS

Nerve fiber length (NFL) was significantly different between patients without diabetic retinopathy and controls (p = 0.028). In patients with non-proliferative diabetic retinopathy (NPDR) and patients with proliferative diabetic retinopathy (PDR), nerve fiber parameters including density (NFD), NFL, and corneal nerve branching (NB) showed a difference with increasing significance compared to healthy persons. A history of nephropathy and/or peripheral neuropathy (all p < 0.001), decreased corneal sensation (all p < or = 0.03), and pathological vibration sensation (p < or = 0.04) were significantly associated with a decrease in NFD, NFL, and NB (except vibration sensation). Unexpectedly, diabetic patients with normal corneal and vibration sensation demonstrated significant changes in NFD (p = 0.005), NFL, and NB (both p = 0.001) compared to healthy volunteers with intact corneal and vibration sensation.

CONCLUSION

Confocal microscopy is a valuable tool for demonstrating subtle corneal nerve alterations in vivo. It is capable of demonstrating diabetic nerve fiber damage earlier than corneal sensation testing and vibration perception assessment in the lower limb.

Anatomy of the human corneal innervation

The anatomy of the human corneal innervation has been the subject of much investigation; however, a comprehensive description remains elusive. The purpose of the present study was to provide a detailed description of the human corneal innervation using a novel approach involving immunohistochemically stained anterior-cornea whole mounts. Sixteen donor corneas aged 19-78 years were cut with a 6.0 mm trephine into a central plug and two peripheral rims. Each specimen was sectioned serially on a cryostat to produce several 100 microm-thick stromal sections and a 100-140 microm-thick anterior-cornea whole mount that contained the entire corneal epithelium and much of the anterior stroma. The corneal innervation was stained with a primary antibody against beta neurotubulin and subjected to rigorous quantitative and qualitative analyses. The results showed that a mean of 71.3 +/- 14.3, uniformly spaced, main stromal nerve bundles entered the cornea at the corneoscleral limbus. The bundles averaged 20.3 +/- 7.0 microm in diameter, were separated by a mean spacing of 0.49 +/- 0.40 mm, and entered the cornea at a mean distance of 293 +/- 106 microm from the ocular surface. Each stromal bundle gave rise through repetitive branching to a moderately dense midstromal plexus and a dense subepithelial plexus (SEP). The SEP was comprised of modest numbers of straight and curvilinear nerves, most of which penetrated Bowman's membrane to supply the corneal epithelium, and a more abundant and anatomically complex population of tortuous, highly anastomotic nerves that remained largely confined in their distribution to the SEP. SEP density and anatomical complexity varied considerably among corneas and was less dense and patchier in the central cornea. A mean of 204 +/- 58.5 stromal nerves penetrated Bowman's membrane to supply the central 10 mm of corneal epithelium (2.60 nerves/mm(2)). The density of Bowman's membrane penetrations was greater peripherally than centrally. After entering the epithelium, stromal nerves branched into groups of up to twenty subbasal nerve fibers known as epithelial leashes. Leashes in the central and intermediate cornea anastomosed extensively to form a dense, continuous subbasal nerve plexus, while leashes in the peripheral cornea demonstrated fewer anastomoses and were less complex anatomically. Viewed in its entirety, the subbasal nerve plexus formed a gentle, whorl-like assemblage of long curvilinear subbasal fibers, 1.0-8.0 mm in length, that converged on an imaginary seam or gentle spiral (vortex) approximately 2.51 +/- 0.23 mm inferonasal to the corneal apex. Mean subbasal nerve fiber density near the corneal apex was 45.94 +/- 5.20 mm/mm(2) and mean subbasal and interconnecting nerve fiber diameters in the same region were 1.51 +/- 0.74 microm and 0.69 +/- 0.26 microm, respectively. Intraepithelial terminals originated exclusively as branches of subbasal nerves and terminated in all epithelial layers. Nerve terminals in the wing and squamous cell layers were morphologically diverse and ranged in total length from 9 to 780 microm. The suprabasal layers of the central corneal epithelium contained approximately 605.8 terminals/mm(2). The results of this study provide a detailed, comprehensive description of human corneal nerve architecture and density that extends and refines existing accounts. An accurate, detailed model of the normal human corneal innervation may predict or help to understand the consequences of corneal nerve damage during refractive, cataract and other ocular surgeries.