L V Prasad Eye Institute, Andhra Pradesh, India is a tertiary care eye hospital and a WHO collaborating centre in prevention of blindness. Data pertaining to all cataract surgeries performed by trainees during one quarter (1 July 2007 to 30 September 2007) were analysed. A trainee is defined as someone who has completed his/her ophthalmology residency and has joined for fellowship programme at the institute. All cataract surgeries performed by 22 trainees using either MSICS or phacoemulsification were included in the study. Surgeries which were primarily large incision extracapsular or intracapsular cataract extraction and performed on patients less than 20 years of age were excluded. Approval of the Ethics Committee of the Institute was obtained for the data collection.
All the trainees had completed their basic residency in ophthalmology from different centres across India and as a part of training; they are supposed to be trained in microsurgery. However, unlike the developed West, the training standards are quiet variable across the country.21
Hence, to have a uniform standard for these trainees, all of them performed surgeries under supervision, for their first 25–30 cases at our institute. After this, they were allowed to perform surgeries independently.
Preoperative data collection for each eye included the patient age and gender, preoperative visual acuity (uncorrected and best corrected visual acuity; UCVA and BCVA, respectively), details of slit lamp examination of the anterior segment and preexisting ocular conditions likely to influence either the operative course or the final visual acuity.The intraocular pressure was recorded by applanation tonometry in all cases. The posterior pole was examined with slit-lamp biomicroscopy using +90 D or +78 D lens. Indirect ophthalmoscopy was done to evaluate the retinal periphery. The status of the other eye was similarly documented. In the case of non-visibility of posterior segment, B-scan was performed for the eye.
Axial length measurements and keratometry recordings were done and SRK-II formula22
was used to calculate the intraocular lens (IOL) power required. The systemic status of the patient was evaluated to ensure fitness for surgery under local anaesthesia.
Operative data included the name of the resident, consultant in-charge, date of the surgery, technique of surgery employed—including the details of each step and details of the IOL implanted. The occurrence of any intraoperative complication was documented along with the details of the subsequent management.
All surgeries were performed under local (peribulbar) anaesthesia. MSICS was performed by a modified Blumenthal technique.2
After cleaning and draping the eye, a barraquer speculum was applied. A superior rectus bridle suture was applied with 4'0 silk. A paracentesis was made at 10 o'clock position with a micro vitreoretinal (MVR) blade. In cases of total/dense cataracts where the fundal glow was not visible, trypan blue dye was used to stain the anterior capsule. Viscoelastic was injected into the anterior chamber. A capsulorrhexis was performed with the help of a cystitome through the paracentesis. Whenever the capsulorrhexis threatened to extend to the periphery, it was converted to a can-opener capsulotomy. If the size of the rhexis was deemed insufficient for prolapsing of the nucleus into the anterior chamber, two relaxing incisions were made on the rhexis margin. A fornix-based conjunctival flap was made from 10 to 2 o’clock position. A 5.5–6 mm-long scleral incision was made with a No. 15 blade about 1–2 mm posterior to the limbus. Two back cuts (1–2 mm long) were made at the ends, at approximately 45° angulations. A sclero-corneal tunnel was dissected with a crescent, with 1–2 mm dissection into the cornea (and always cutting backwards with the sides of the crescent). An anterior chamber maintainer (ACM) was inserted into the anterior chamber through a slightly longer paracentesis at the infero-lateral aspect of the cornea (7 o’clock for right eye and 5 o'clock for left eye). With the ACM switched on, the anterior chamber was entered with a keratome, and the internal opening was extended up to 7–8 mm, taking care to cut inwards. Hydrodissection and hydrodelineation were performed as deemed appropriate for the case. The nucleus was prolapsed into the anterior chamber either during hydrodissection or by using a sinsky hook and the nucleus was delivered out. Cortical matter was aspirated using the single-port Blumenthal canula with the ACM on. A 6.5 mm polymethyl methacrylate (PMMA) posterior chamber IOL was implanted into the bag, under viscoelastic. Viscoelastic was removed and paracenteses were hydrated. Wound was checked for the absence of leak and if present, it was sutured. Conjunctival flap reposited over the incision. Speculum was removed and the eye was patched after instilling a drop of 2.5% betadine in the conjunctival cul-de-sac.
Phacoemulsification was performed using a peristaltic, Universal-II machine of Alcon Pharmaceuticals (Alcon Laboratories, Fort Worth, Texas, USA), with standard ‘divide and conquer’ technique. A capsulorrhexis was performed from the paracentesis as described earlier. A 5 mm scleral straight incision was made superiorly and a sclera tunnel created. A second paracentesis was made at 2 o'clock position. Hydrodissection and hydrodelineation were performed. After ensuring the free rotation of the nucleus, a four-quadrant technique was used during trenching. Each quadrant was then emulsified and aspirated. Cortical matter was cleaned using automated irrigation and aspiration. A non-foldable PMMA posterior chamber IOL with a 5.25 mm optic was implanted into the capsular bag under viscoelastic. Viscoelastic was removed using automated irrigation and aspiration. Wound was checked for the absence of leak, and if present, was sutured. Conjunctival flap reposited over the incision. Speculum was removed and the eye was patched, after instilling a drop of 2.5% betadine.
In the event of complications or impending complications, the consultants guided the trainees and helped in averting the complication or in managing the problem.
Postoperative data were documented on the first day, between 1 and 3 weeks and finally at 4–11 weeks visit. Prednisolone acetate 1% eye drops six times per day and ofloxacin 0.3% eye drops four times per day were given for the first week. From the second week onwards, antibiotic drops were discontinued and topical steroids were tapered over the next 5 weeks. On each of the visits, uncorrected visual acuity and pin-hole improvement was noted along with detailed slit lamp examination of the anterior segment along with fundus examination, when needed. On the last follow-up (4–11 week visit), in addition to above, refraction was performed and BCVA was noted, and glasses were prescribed.
Statistical analysis was performed using Stata 11.23
For categorical variables, χ2
or Fischer's exact test were used and for continuous variables, Independent sample t test was used. Normality of continuous variable was checked using Shapiro-Wilk test. Logistic regression was used for univariate and multivariate analysis to look for risk factors for poor outcomes (defined as BCVA<6/60 in final follow-up visit). Multicollinearity between variables was assessed looking at the variance inflation factor and fitness of the model was assessed using the Hosmer Lemeshow test for goodness of fit.24